Current Concepts

[58] Saucedo R, Basurto L, Galván R, Sánchez J, Puello E, Zárate A. Duration of lactation is associated with lower leptin levels in patients with gestational diabetes mellitus. Salud(i)Ciencia. 2014;

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

diabetic mothers. Archives of Pediatrics & Adolescent Medicine. 1998;152:

[66] Dabelea D. The predisposition to obesity and diabetes in offspring of diabetic mothers. Diabetes Care. 2007; 30(Supp. 2):S169-S174. DOI: 10.2337/

[67] Halipchuk J, Temple B, Dart A, Martin D, Sellers EAC. Prenatal,

[68] Savino F, Benetti S, Liguori SA, Sorrenti M, Cordero Di Montezemolo L. Advances on human milk hormones and protection against obesity. Cellular and Molecular Biology. 2013;59:89-98

Adatorwovor R, Schwartz TA, Berry DC. A cluster randomized trial of tailored breastfeeding support for women with gestational diabetes. Breastfeeding Medicine. 2016;11:

[69] Stuebe AM, Bonuck K,

504-513

obstetric and perinatal factors associated with the development of childhoodonset type 2 diabetes. Canadian Journal of Diabetes. 2018;42:71-77. DOI: 10.1016/j.jcjd.2017.04.003

249-254

dc07-s211

[59] Feuermann Y, Mabjeesh SJ, Niv-Spector L, Levin D, Shamay A. Prolactin affects leptin action in the bovine mammary gland via the mammary fat pad. The Journal of Endocrinology.

[60] Halaas JL, Gajiwala KS, Maffei M, Cohen SL, Chait BT, Rabinowitz D, et al. Weight-reducing effects of the plasma protein encoded by the obese gene.

[61] Casabiell X, Piñeiro V, Tomé MA, Peinó R, Diéguez C, Casanueva FF. Presence of leptin in colostrum and/or breast milk from lactating mothers: A potential role in the regulation of neonatal food intake. The Journal of Clinical Endocrinology and Metabolism.

[62] Schueler J, Alexander B, Hart AM, Austin K, Larson-Meyer DE. Presence and dynamics of leptin, GLP-1, and PYY

postpartum. Obesity. 2013;21:1451-1458.

[63] Bouret SG. Early life origins of obesity: Role of hypothalamic programming. Journal of Pediatric Gastroenterology and Nutrition. 2009; 48(Supp. 1):S31-S38. DOI: 10.1097/

[64] Retnakaran R, Hanley AJ, Raif N, Connelly PW, Sermer M, Zinman B. Reduced adiponectin concentration in women with gestational diabetes: A potential factor in progression to type 2 diabetes. Diabetes Care. 2004;27:

[65] Cordero L, Treuer SH, Landon MB, Gabbe SG. Management of infants of

in human breast milk at early

DOI: 10.1002/oby.20345

MPG.0b013e3181977375

799-800

82

20:581-585

2006;191:407-413

1997;82:4270-4273

Science. 1995;269:543-546

**85**

**Chapter 6**

**Abstract**

pregnancy

**1. Introduction**

MicroRNAs

*and Sumaiya Adam*

Screening for Gestational

*Carmen Pheiffer, Stephanie Dias, Paul Rheeder* 

Diabetes Mellitus: The Potential of

Gestational diabetes mellitus (GDM) is associated with short- and long-term complications in both mothers and their offspring. Screening and early diagnosis of GDM is advocated as a strategy to prevent adverse pregnancy outcomes. However, there is currently no test that is amenable to routine screening, particularly in low-and middle-income countries. MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression post-transcriptionally. In recent years, miRNAs have been the focus of increasing research due to their important role in regulating biological pathways and their aberrant expression during disease. The discovery of circulating miRNAs in maternal blood, and their altered expression during pregnancy-associated complications have increased interest into their potential as diagnostic biomarkers for GDM. In this review, we summarise studies that have investigated miRNAs in maternal blood thus providing an update of the current status of miRNAs as biomarkers for GDM. We also discuss the challenges of miRNA profiling, and highlight perspectives and recommendations for research.

**Keywords:** gestational diabetes mellitus, biomarkers, epigenetics, microRNAs,

Gestational diabetes mellitus (GDM) is defined as glucose intolerance that is first diagnosed during pregnancy with glucose homeostasis usually restored shortly after birth. The rate of GDM has constantly increased over the last 20 years [1], and in 2017 the International Diabetes Federation estimated that about 14% of women with live births had GDM [2]. Without appropriate glucose management, GDM is associated with short- and long-term complications in both mothers and their offspring [3–6]. Treatment of GDM is effective in preventing these adverse outcomes [7–11], thus, universal screening and early detection of GDM is widely advocated as a strategy to promote timely treatment and improve pregnancy outcomes [3]. The oral glucose tolerance test (OGTT) conducted between the 24th and 28th week of pregnancy, is currently the gold standard for GDM diagnosis [12]. However, the test is time-consuming, expensive and unfeasible in most countries. The identification of simple and cost-effective biomarkers that do not require fasting and multiple blood draws would be more acceptable to pregnant women, and thereby facilitate

#### **Chapter 6**

## Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs

*Carmen Pheiffer, Stephanie Dias, Paul Rheeder and Sumaiya Adam*

#### **Abstract**

Gestational diabetes mellitus (GDM) is associated with short- and long-term complications in both mothers and their offspring. Screening and early diagnosis of GDM is advocated as a strategy to prevent adverse pregnancy outcomes. However, there is currently no test that is amenable to routine screening, particularly in low-and middle-income countries. MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression post-transcriptionally. In recent years, miRNAs have been the focus of increasing research due to their important role in regulating biological pathways and their aberrant expression during disease. The discovery of circulating miRNAs in maternal blood, and their altered expression during pregnancy-associated complications have increased interest into their potential as diagnostic biomarkers for GDM. In this review, we summarise studies that have investigated miRNAs in maternal blood thus providing an update of the current status of miRNAs as biomarkers for GDM. We also discuss the challenges of miRNA profiling, and highlight perspectives and recommendations for research.

**Keywords:** gestational diabetes mellitus, biomarkers, epigenetics, microRNAs, pregnancy

#### **1. Introduction**

Gestational diabetes mellitus (GDM) is defined as glucose intolerance that is first diagnosed during pregnancy with glucose homeostasis usually restored shortly after birth. The rate of GDM has constantly increased over the last 20 years [1], and in 2017 the International Diabetes Federation estimated that about 14% of women with live births had GDM [2]. Without appropriate glucose management, GDM is associated with short- and long-term complications in both mothers and their offspring [3–6]. Treatment of GDM is effective in preventing these adverse outcomes [7–11], thus, universal screening and early detection of GDM is widely advocated as a strategy to promote timely treatment and improve pregnancy outcomes [3]. The oral glucose tolerance test (OGTT) conducted between the 24th and 28th week of pregnancy, is currently the gold standard for GDM diagnosis [12]. However, the test is time-consuming, expensive and unfeasible in most countries. The identification of simple and cost-effective biomarkers that do not require fasting and multiple blood draws would be more acceptable to pregnant women, and thereby facilitate

screening for GDM. MicroRNAs (miRNAs) are small noncoding RNA molecules that regulate various metabolic pathways. They are implicated in the pathophysiology of various diseases and have attracted considerable interest as biomarkers of metabolic disease. Recently, several studies have explored their potential as biomarkers of GDM. The purpose of this review is to provide an update of the status of miRNAs as biomarkers for GDM. All studies that have profiled miRNAs in maternal blood during GDM to date are summarised. We also discuss the challenges of miRNA research, and highlight perspectives and recommendations for future research.

#### **2. Overview of gestational diabetes**

Hyperglycaemia during pregnancy creates an adverse intrauterine environment that predisposes both mother and offspring to perinatal complications and future metabolic disease [3–6]. Maternal perinatal complications include caesarean section, preeclampsia and birth injuries. Women with pregnancies complicated by GDM also have an increased risk of developing disease in later life. In 2009, Bellamy et al. conducted a comprehensive review of the literature and found that women who have had GDM are at least seven-fold more likely to develop Type 2 diabetes (T2D) compared to women with normoglycaemic pregnancies [4]. Other studies showed that GDM is associated with the development of metabolic disease [13], cardiovascular disease [14] and breast cancer [15].

Foetal and neonatal complications associated with GDM include macrosomia, congenital malformations, perinatal death, hypertrophic cardiomyopathy, intrauterine growth restriction, preterm birth, respiratory distress syndrome, hypoglycaemia, hypocalcaemia, polycythaemia and hyperbilirubinemia [5]. In recent years, increasing evidence support the critical role of the intrauterine environment in programming the foetus and influencing long-term offspring health [16]. In the 1980s, David Barker and his colleagues proposed *Barker's hypothesis* or *the developmental origins of adult disease*, which suggests that metabolic diseases have their origins in early development [17]. Subsequently, several other studies have reported that diabetes during pregnancy is associated with the development of obesity and diabetes in children [5].

The prevalence of GDM is rapidly increasing, spurred by the global obesity pandemic. Pregnant women who are overweight, obese or severely obese have a 2.14-, 3.56- and 8.56-fold risk of developing GDM compared to normal weight women [18]. The short- and long-term consequences of GDM are likely to have a major negative impact, particularly on low- and middle-income countries that already have limited financial and human resources, and are least able to respond to the challenge. Screening and treatment of GDM leads to improved pregnancy outcomes [7–11], thus universal screening for GDM is widely advocated as a strategy to prevent pregnancy complications. However, the OGTT, which is considered the gold standard for GDM diagnosis is not amenable to routine screening [3]. Currently, traditional risk-factor screening based on obesity, age older than ≥35 years, nonwhite ethnicity, and having a family history of diabetes [3] is mostly employed. Unfortunately, these risk factors have poor predictive value [19, 20]. A number of other laboratory tests such as glycated haemoglobin (HbA1c), insulin, adiponectin, glycosylated fibronectin and C-reactive protein have been explored, however, they too have several challenges and are not yet clinically applicable [3].

#### **3. Characteristics of ideal biomarkers**

Biomarkers are defined as "cellular, biochemical or molecular alterations that are measurable in biological media such as human tissues, cells or fluids" [21].

**87**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

to induce predominantly mRNA degradation [25, 26].

prevent or treat T2D, making them attractive therapeutic targets [31].

The identification of circulating miRNAs in biological fluids such as whole blood, serum, plasma and urine has sparked research efforts to investigate their

Screening, diagnostic and prognostic biomarkers offer several advantages and thus efforts to identify biomarkers of disease have intensified. They are clinically useful and can be used to detect or monitor disease progression, thus facilitating earlier diagnosis and disease management. Furthermore, biomarkers are able to monitor pharmacological responses and predict clinical outcome. As recently reviewed by Etheridge et al. [22], characteristics of the ideal biomarker include sensitivity, specificity, cost-effectiveness, reproducibility, robustness, accessibility, stability and ability to differentiate between pathologies. Recent advancements in molecular biology have led to the development of molecular biomarkers that are sensitive and specific, and are easily measured in biological fluids such as whole blood, plasma

MiRNAs are epigenetic mechanisms that reflect gene-environment interactions and are increasingly being implicated in the pathophysiology of metabolic diseases [23]. Since their discovery in *Caenorhabditis elegans* in 1993 [24], miRNAs have emerged as one of the most powerful epigenetic mechanisms regulating diverse biological processes including development, proliferation, differentiation and apoptosis [25]. They are short, single-stranded, highly conserved, non-coding RNA molecules of approximately 22 nucleotides in length that regulate gene expression through post-transcriptional mechanisms. MiRNAs bind to the 3′ untranslated region (UTR) of messenger RNA (mRNA) inducing degradation or translational repression of the mRNA transcript [26]. Using an elegant set of experiments, Guo et al. showed that destabilisation of target mRNAs rather than translational repression is the main mechanism whereby miRNAs reduce protein expression [26]. A single miRNA is able to regulate up to 200 target genes, implying that about 30% of the genome is regulated by miRNAs [27, 28] and confirming the important role of miRNAs as mediators of biological function. More than 2000 miRNAs are present in the human genome, and function in various biological processes [27–29]. Mature miRNAs are produced through a stepwise process. Briefly, primary miRNA transcripts (pri-miRNAs) are transcribed in the nucleus by RNA polymerase II (and possibly by RNA polymerase III), which are then cleaved by Drosha RNase III endonuclease to produce stem-loop precursor miRNAs (pre-miRNAs) that are approximately 70 nucleotides long. Ran-GTP and the export receptor, Exportin-5 transports pre-miRNAs to the cytoplasm, where Dicer, also a RNase III endonuclease, cleaves them to produce mature miRNAs. Mature miRNAs complex with the RNA-induced silencing complex (RISC) and bind to the 3' UTR of mRNA

MiRNAs regulate a wide range of biological processes including cell proliferation and differentiation, apoptosis and metabolism, thus it is not surprising that altered miRNA expression have been shown to associated with various conditions including cancer, obesity, T2D and cardiovascular disease [30]. MiRNAs play a critical role in the pathophysiology of metabolic disease, and their aberrant expression is observed in tissues associated with disease. For example, various *in vitro*, *in vivo* animal models and studies in diabetic patients have demonstrated the altered expression of miRNAs that regulate insulin secretion, adipocyte differentiation, lipid metabolism, inflammation and glucose homeostasis in dysfunctional pancreatic beta cells and insulin-resistant target tissues, such as adipose, liver and muscle during T2D [23]. Increasingly evidence show that correcting aberrant miRNA expression can

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

and serum [22].

**4. MicroRNAs**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs DOI: http://dx.doi.org/10.5772/intechopen.82102*

Screening, diagnostic and prognostic biomarkers offer several advantages and thus efforts to identify biomarkers of disease have intensified. They are clinically useful and can be used to detect or monitor disease progression, thus facilitating earlier diagnosis and disease management. Furthermore, biomarkers are able to monitor pharmacological responses and predict clinical outcome. As recently reviewed by Etheridge et al. [22], characteristics of the ideal biomarker include sensitivity, specificity, cost-effectiveness, reproducibility, robustness, accessibility, stability and ability to differentiate between pathologies. Recent advancements in molecular biology have led to the development of molecular biomarkers that are sensitive and specific, and are easily measured in biological fluids such as whole blood, plasma and serum [22].

#### **4. MicroRNAs**

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

and highlight perspectives and recommendations for future research.

**2. Overview of gestational diabetes**

cardiovascular disease [14] and breast cancer [15].

too have several challenges and are not yet clinically applicable [3].

Biomarkers are defined as "cellular, biochemical or molecular alterations that are measurable in biological media such as human tissues, cells or fluids" [21].

**3. Characteristics of ideal biomarkers**

screening for GDM. MicroRNAs (miRNAs) are small noncoding RNA molecules that regulate various metabolic pathways. They are implicated in the pathophysiology of various diseases and have attracted considerable interest as biomarkers of metabolic disease. Recently, several studies have explored their potential as biomarkers of GDM. The purpose of this review is to provide an update of the status of miRNAs as biomarkers for GDM. All studies that have profiled miRNAs in maternal blood during GDM to date are summarised. We also discuss the challenges of miRNA research,

Hyperglycaemia during pregnancy creates an adverse intrauterine environment that predisposes both mother and offspring to perinatal complications and future metabolic disease [3–6]. Maternal perinatal complications include caesarean section, preeclampsia and birth injuries. Women with pregnancies complicated by GDM also have an increased risk of developing disease in later life. In 2009, Bellamy et al. conducted a comprehensive review of the literature and found that women who have had GDM are at least seven-fold more likely to develop Type 2 diabetes (T2D) compared to women with normoglycaemic pregnancies [4]. Other studies showed that GDM is associated with the development of metabolic disease [13],

Foetal and neonatal complications associated with GDM include macrosomia, congenital malformations, perinatal death, hypertrophic cardiomyopathy, intrauterine growth restriction, preterm birth, respiratory distress syndrome, hypoglycaemia, hypocalcaemia, polycythaemia and hyperbilirubinemia [5]. In recent years, increasing evidence support the critical role of the intrauterine environment in programming the foetus and influencing long-term offspring health [16]. In the 1980s, David Barker and his colleagues proposed *Barker's hypothesis* or *the developmental origins of adult disease*, which suggests that metabolic diseases have their origins in early development [17]. Subsequently, several other studies have reported that diabetes during pregnancy is associated with the development of obesity and diabetes in children [5]. The prevalence of GDM is rapidly increasing, spurred by the global obesity pandemic. Pregnant women who are overweight, obese or severely obese have a 2.14-, 3.56- and 8.56-fold risk of developing GDM compared to normal weight women [18]. The short- and long-term consequences of GDM are likely to have a major negative impact, particularly on low- and middle-income countries that already have limited financial and human resources, and are least able to respond to the challenge. Screening and treatment of GDM leads to improved pregnancy outcomes [7–11], thus universal screening for GDM is widely advocated as a strategy to prevent pregnancy complications. However, the OGTT, which is considered the gold standard for GDM diagnosis is not amenable to routine screening [3]. Currently, traditional risk-factor screening based on obesity, age older than ≥35 years, nonwhite ethnicity, and having a family history of diabetes [3] is mostly employed. Unfortunately, these risk factors have poor predictive value [19, 20]. A number of other laboratory tests such as glycated haemoglobin (HbA1c), insulin, adiponectin, glycosylated fibronectin and C-reactive protein have been explored, however, they

**86**

MiRNAs are epigenetic mechanisms that reflect gene-environment interactions and are increasingly being implicated in the pathophysiology of metabolic diseases [23]. Since their discovery in *Caenorhabditis elegans* in 1993 [24], miRNAs have emerged as one of the most powerful epigenetic mechanisms regulating diverse biological processes including development, proliferation, differentiation and apoptosis [25]. They are short, single-stranded, highly conserved, non-coding RNA molecules of approximately 22 nucleotides in length that regulate gene expression through post-transcriptional mechanisms. MiRNAs bind to the 3′ untranslated region (UTR) of messenger RNA (mRNA) inducing degradation or translational repression of the mRNA transcript [26]. Using an elegant set of experiments, Guo et al. showed that destabilisation of target mRNAs rather than translational repression is the main mechanism whereby miRNAs reduce protein expression [26]. A single miRNA is able to regulate up to 200 target genes, implying that about 30% of the genome is regulated by miRNAs [27, 28] and confirming the important role of miRNAs as mediators of biological function. More than 2000 miRNAs are present in the human genome, and function in various biological processes [27–29].

Mature miRNAs are produced through a stepwise process. Briefly, primary miRNA transcripts (pri-miRNAs) are transcribed in the nucleus by RNA polymerase II (and possibly by RNA polymerase III), which are then cleaved by Drosha RNase III endonuclease to produce stem-loop precursor miRNAs (pre-miRNAs) that are approximately 70 nucleotides long. Ran-GTP and the export receptor, Exportin-5 transports pre-miRNAs to the cytoplasm, where Dicer, also a RNase III endonuclease, cleaves them to produce mature miRNAs. Mature miRNAs complex with the RNA-induced silencing complex (RISC) and bind to the 3' UTR of mRNA to induce predominantly mRNA degradation [25, 26].

MiRNAs regulate a wide range of biological processes including cell proliferation and differentiation, apoptosis and metabolism, thus it is not surprising that altered miRNA expression have been shown to associated with various conditions including cancer, obesity, T2D and cardiovascular disease [30]. MiRNAs play a critical role in the pathophysiology of metabolic disease, and their aberrant expression is observed in tissues associated with disease. For example, various *in vitro*, *in vivo* animal models and studies in diabetic patients have demonstrated the altered expression of miRNAs that regulate insulin secretion, adipocyte differentiation, lipid metabolism, inflammation and glucose homeostasis in dysfunctional pancreatic beta cells and insulin-resistant target tissues, such as adipose, liver and muscle during T2D [23]. Increasingly evidence show that correcting aberrant miRNA expression can prevent or treat T2D, making them attractive therapeutic targets [31].

The identification of circulating miRNAs in biological fluids such as whole blood, serum, plasma and urine has sparked research efforts to investigate their feasibility as diagnostic or prognostic biomarkers of disease [32–34]. Circulating miRNAs are speculated to reflect tissue expression, to play a central role in cell-tocell communication and to be associated with disease progression [33–35]. Other attributes that make miRNAs attractive biomarkers is their stability and robust expression [22], even in degraded RNA samples [36]. Technological advances and the development of various platforms for miRNA profiling have bolstered the popularity of miRNAs [37], and have enabled relative easy and cost-effective methods of quantification using sensitive techniques such as quantitative real time PCR (qRT-PCR) [22, 32, 38]. Circulating miRNAs are thought to be released from cells as exosomes, microvesicles, apoptotic bodies, or are non-vesicle bound and encapsulated in protein or lipid complexes [32]. A number of studies [39–41], have demonstrated that circulating miRNAs are associated with glucose homeostasis and are dysregulated during T2D progression. Recently, we showed that the expression of miR-27b is increased in peripheral blood cells and serum of South African women with impaired glucose tolerance compared to normoglycaemia [42] and identified novel miRNAs associated with dysglycaemia in these women [43]. Putative gene targets of these novel miRNAs were enriched in biological processes involved in key aspects of glucose regulation, and receiver operating characteristic (ROC) curve analysis demonstrated that the diagnostic utility of these miRNAs were similar to fasting insulin [43]. Intriguingly, Parrizas et al. showed that an exercise intervention was able to reverse the aberrant expression of miR-192 and miR-193b induced by impaired glucose tolerance [44], while Luo et al. [45] showed that platelet-derived miR-126 was altered during T2D progression, and that glucose lowering treatment was able to normalise its expression. These studies provide support for the use of miRNAs as diagnostic and prognostic biomarkers to monitor treatment response.

#### **5. MicroRNAs, pregnancy and gestational diabetes**

MiRNAs play an important role as metabolic and developmental regulators during pregnancy. They respond to changing physiological conditions during pregnancy, while their dysregulation contributes to pregnancy-related disorders [46]. Thus far over 600 placental miRNAs have been identified [47]. Altered placental miRNA expression has been demonstrated in several pregnancy related disorders. In 2007, Pineles et al. were the first to demonstrate altered miRNA expression during preeclampsia. They reported that the expression of two miRNAs, miR-210 and miR-182, were increased during preeclampsia [48]. In 2009, using microarrays, Hu et al. and Zhu et al. identified seven and 34 miRNAs, respectively, that are dysregulated in preeclamptic compared to normal pregnancies [49, 50]. Subsequently, other studies have reported differential miRNA expression during preeclampsia and importantly provide experimental evidence to support the involvement of these miRNAs in disease pathophysiology [51, 52]. Altered miRNA expression has also been observed in other pregnancy complications such as macrosomia [53], preterm delivery and small for gestational age [54].

Placental-derived miRNAs in maternal blood have potential as biomarkers for pregnancy monitoring [54, 55]. It is suggested that miRNAs from placental tissue are exported into the maternal circulation via exosomes, and that these miRNAs reflect the physiological status of pregnancy and may thus have diagnostic potential [56]. Many of studies have reported that maternal circulating miRNAs are associated with placental weight [57], placental dysfunction [58, 59] and pregnancy complications [54, 60–63]. MiR-517c was increased in pregnancies complicated with placental abruption [59], miR-515, miR-516a, miR-516b, miR-518b, miR-519d, miR-520a, miR-520h, miR-525, miR-526b and miR-1323 were increased during

**89**

ing the clinical value of miRNAs.

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

miRNAs as predictive biomarkers for pregnancy complications.

Growing evidence implicate miRNAs in the pathogenesis of GDM [47] and suggest that maternal miRNA expression may be used as biomarkers to predict GDM. Indeed, many GDM associated miRNAs are also expressed in placentas of women with Type 1 diabetes and T2D, confirming that miRNAs expressed during GDM play an important role in metabolic regulation and reflects some of the shared aetiology between these different types of diabetes [66]. Interestingly, a subset of miRNAs were distinct for each type of diabetes, illustrating their potential to differentiate between GDM and other manifestations of diabetes. Several other studies have reported that placental miRNA expression is altered in women with GDM. Zhao et al. reported that miR-518d is upregulated in placentas of women with GDM compared to controls, and further showed that increased expression of miR-518d correlated with decreased protein expression of peroxisome proliferatoractivated receptor-α (PPARα) [67], a major regulatory transcription factor in lipid homeostasis and energy metabolism [68, 69]. Li et al. identified nine miRNAs that are dysregulated in placentas of women with GDM, the expression of miR-508 was increased and miR-9, miR-27a, miR-30d, miR-33a, miR-92a, miR-137, miR-362 and miR-502 were decreased. Importantly, the decreased expression of these miRNAs correlated with increased protein expression of their gene targets, epidermal growth factor receptor (EGFR), phosphoinositide 3-Kinase (PI3K) and protein kinase B (Akt), key proteins in placental development and foetal growth [70]. Other studies showed that miR-98 [71] and miR-503 [72] are upregulated and miR-143 is downregulated [73] in placentas of women with GDM compared to women with normoglycaemic pregnancies. Intriguingly, the expression of miR-143 differentiated between GDM managed by diet or medication [71], further support-

Xu et al. showed that the increased expression of miR-503 in the placentas of women with GDM compared to normoglycaemic pregnancies, are reflected in plasma [72]. The studies that have quantified circulating miRNA expression during GDM are summarised in **Table 1**. In 2011, Zhao et al. were the first to profile the expression of serum miRNAs during GDM [74]. Using Taqman low density arrays, followed by confirmation with individual qRT-PCR, they found that serum expression of miR-29a, miR-132 and miR-222 were decreased during GDM. Importantly, these results were validated in an internal and external cohort. Notably, serum for miRNA profiling in the discovery cohort was collected at 16–19 weeks of pregnancy, while GDM was diagnosed at 24–28 weeks of pregnancy, thus illustrating

preeclampsia [63], miR-516, miR-517, miR-520a, miR-525 and miR-526a were upregulated during preeclampsia, gestational hypertension and foetal growth restriction [60], miR-517a was increased and miR-518b was decreased during placenta previa [58], and miR-346 and miR-582 were increased during preeclampsia, preterm delivery and small for gestational age patients compared to normal controls [54]. Importantly, Hromadnikova et al. showed that upregulation of plasma miR-517, miR-518b and miR-520h during the first trimester was associated with the development of preeclampsia, and provided evidence to suggest that miR-517 could predict preeclampsia [61]. Furthermore, a number of studies have reported that circulating miRNAs are associated with macrosomia [62, 64, 65]. Jiang and colleagues demonstrated that maternal expression of miR-21, and to a lesser extent miR-20a in serum samples from pregnant women in the third trimester was associated with macrosomia [62], Hu et al. reported that macrosomia was associated with decreased serum expression of miR-376a [64], while Ge et al. reported that the expression of miR-18a, miR-141, miR-143, miR-200c and miR-221 were decreased, and miR-16, miR-30a and miR-523 were increased in the plasma of pregnant women with foetal macrosomia compared to normal controls [65], further supporting the use of

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

#### *Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs DOI: http://dx.doi.org/10.5772/intechopen.82102*

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

feasibility as diagnostic or prognostic biomarkers of disease [32–34]. Circulating miRNAs are speculated to reflect tissue expression, to play a central role in cell-tocell communication and to be associated with disease progression [33–35]. Other attributes that make miRNAs attractive biomarkers is their stability and robust expression [22], even in degraded RNA samples [36]. Technological advances and the development of various platforms for miRNA profiling have bolstered the popularity of miRNAs [37], and have enabled relative easy and cost-effective methods of quantification using sensitive techniques such as quantitative real time PCR (qRT-PCR) [22, 32, 38]. Circulating miRNAs are thought to be released from cells as exosomes, microvesicles, apoptotic bodies, or are non-vesicle bound and encapsulated in protein or lipid complexes [32]. A number of studies [39–41], have demonstrated that circulating miRNAs are associated with glucose homeostasis and are dysregulated during T2D progression. Recently, we showed that the expression of miR-27b is increased in peripheral blood cells and serum of South African women with impaired glucose tolerance compared to normoglycaemia [42] and identified novel miRNAs associated with dysglycaemia in these women [43]. Putative gene targets of these novel miRNAs were enriched in biological processes involved in key aspects of glucose regulation, and receiver operating characteristic (ROC) curve analysis demonstrated that the diagnostic utility of these miRNAs were similar to fasting insulin [43]. Intriguingly, Parrizas et al. showed that an exercise intervention was able to reverse the aberrant expression of miR-192 and miR-193b induced by impaired glucose tolerance [44], while Luo et al. [45] showed that platelet-derived miR-126 was altered during T2D progression, and that glucose lowering treatment was able to normalise its expression. These studies provide support for the use of miRNAs as

diagnostic and prognostic biomarkers to monitor treatment response.

MiRNAs play an important role as metabolic and developmental regulators during pregnancy. They respond to changing physiological conditions during pregnancy, while their dysregulation contributes to pregnancy-related disorders [46]. Thus far over 600 placental miRNAs have been identified [47]. Altered placental miRNA expression has been demonstrated in several pregnancy related disorders. In 2007, Pineles et al. were the first to demonstrate altered miRNA expression during preeclampsia. They reported that the expression of two miRNAs, miR-210 and miR-182, were increased during preeclampsia [48]. In 2009, using microarrays, Hu et al. and Zhu et al. identified seven and 34 miRNAs, respectively, that are dysregulated in preeclamptic compared to normal pregnancies [49, 50]. Subsequently, other studies have reported differential miRNA expression during preeclampsia and importantly provide experimental evidence to support the involvement of these miRNAs in disease pathophysiology [51, 52]. Altered miRNA expression has also been observed in other pregnancy complications such as macrosomia [53], preterm

Placental-derived miRNAs in maternal blood have potential as biomarkers for pregnancy monitoring [54, 55]. It is suggested that miRNAs from placental tissue are exported into the maternal circulation via exosomes, and that these miRNAs reflect the physiological status of pregnancy and may thus have diagnostic potential [56]. Many of studies have reported that maternal circulating miRNAs are associated with placental weight [57], placental dysfunction [58, 59] and pregnancy complications [54, 60–63]. MiR-517c was increased in pregnancies complicated with placental abruption [59], miR-515, miR-516a, miR-516b, miR-518b, miR-519d, miR-520a, miR-520h, miR-525, miR-526b and miR-1323 were increased during

**5. MicroRNAs, pregnancy and gestational diabetes**

delivery and small for gestational age [54].

**88**

preeclampsia [63], miR-516, miR-517, miR-520a, miR-525 and miR-526a were upregulated during preeclampsia, gestational hypertension and foetal growth restriction [60], miR-517a was increased and miR-518b was decreased during placenta previa [58], and miR-346 and miR-582 were increased during preeclampsia, preterm delivery and small for gestational age patients compared to normal controls [54]. Importantly, Hromadnikova et al. showed that upregulation of plasma miR-517, miR-518b and miR-520h during the first trimester was associated with the development of preeclampsia, and provided evidence to suggest that miR-517 could predict preeclampsia [61]. Furthermore, a number of studies have reported that circulating miRNAs are associated with macrosomia [62, 64, 65]. Jiang and colleagues demonstrated that maternal expression of miR-21, and to a lesser extent miR-20a in serum samples from pregnant women in the third trimester was associated with macrosomia [62], Hu et al. reported that macrosomia was associated with decreased serum expression of miR-376a [64], while Ge et al. reported that the expression of miR-18a, miR-141, miR-143, miR-200c and miR-221 were decreased, and miR-16, miR-30a and miR-523 were increased in the plasma of pregnant women with foetal macrosomia compared to normal controls [65], further supporting the use of miRNAs as predictive biomarkers for pregnancy complications.

Growing evidence implicate miRNAs in the pathogenesis of GDM [47] and suggest that maternal miRNA expression may be used as biomarkers to predict GDM. Indeed, many GDM associated miRNAs are also expressed in placentas of women with Type 1 diabetes and T2D, confirming that miRNAs expressed during GDM play an important role in metabolic regulation and reflects some of the shared aetiology between these different types of diabetes [66]. Interestingly, a subset of miRNAs were distinct for each type of diabetes, illustrating their potential to differentiate between GDM and other manifestations of diabetes. Several other studies have reported that placental miRNA expression is altered in women with GDM. Zhao et al. reported that miR-518d is upregulated in placentas of women with GDM compared to controls, and further showed that increased expression of miR-518d correlated with decreased protein expression of peroxisome proliferatoractivated receptor-α (PPARα) [67], a major regulatory transcription factor in lipid homeostasis and energy metabolism [68, 69]. Li et al. identified nine miRNAs that are dysregulated in placentas of women with GDM, the expression of miR-508 was increased and miR-9, miR-27a, miR-30d, miR-33a, miR-92a, miR-137, miR-362 and miR-502 were decreased. Importantly, the decreased expression of these miRNAs correlated with increased protein expression of their gene targets, epidermal growth factor receptor (EGFR), phosphoinositide 3-Kinase (PI3K) and protein kinase B (Akt), key proteins in placental development and foetal growth [70]. Other studies showed that miR-98 [71] and miR-503 [72] are upregulated and miR-143 is downregulated [73] in placentas of women with GDM compared to women with normoglycaemic pregnancies. Intriguingly, the expression of miR-143 differentiated between GDM managed by diet or medication [71], further supporting the clinical value of miRNAs.

Xu et al. showed that the increased expression of miR-503 in the placentas of women with GDM compared to normoglycaemic pregnancies, are reflected in plasma [72]. The studies that have quantified circulating miRNA expression during GDM are summarised in **Table 1**. In 2011, Zhao et al. were the first to profile the expression of serum miRNAs during GDM [74]. Using Taqman low density arrays, followed by confirmation with individual qRT-PCR, they found that serum expression of miR-29a, miR-132 and miR-222 were decreased during GDM. Importantly, these results were validated in an internal and external cohort. Notably, serum for miRNA profiling in the discovery cohort was collected at 16–19 weeks of pregnancy, while GDM was diagnosed at 24–28 weeks of pregnancy, thus illustrating


**91**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

**Upregulated**

miR-200b miR-125b miR-1290

**Downregulated**

Plasma qRT-PCR miR-137 – – RNU6 [81]

Plasma qRT-PCR miR-503 – – NK [72]

**No change**

– – Cel-

**Normali sation**

miR-39

**Ref**

[95]

**Detection method**

Serum qRT-PCR miR-183

the potential of these miRNAs as screening tools for GDM. Recently, Pheiffer et al. reported that the expression of miR-29a, miR-132 and miR-222 were similarly decreased in the serum of South African women with GDM, however, only the latter was statistically significant [75]. Conflictingly, Tagoma et al. showed that miR-222 was increased in plasma of women with GDM compared to normoglycaemic pregnancies [76]. Moreover, Wander et al., observed no differences in the expression of miR-29a and miR-222 in the plasma of American women with or without GDM [77], thus illustrating the heterogeneity of miRNA expression.

*GDM: gestational diabetes mellitus; qRT-PCR: quantitative real time polymerase chain reaction; NK: not known.*

*Validated in internal (36 GDM/36 controls) and two external cohorts (16 GDM/16 controls each).*

*Studies investigating microRNA expression in maternal blood during gestational diabetes mellitus.*

In 2015, Zhu et al. used high-throughput sequencing and qRT-PCR to investigate

Although these miRNAs were identified in plasma or serum, bioinformatics [75, 78] and experimental [74] functional analyses provided support for their biological relevance and role in the pathogenesis of GDM. Other studies also confirm the importance of miRNAs during GDM. For example, in 2014, Shi et al. reported that the expression of miR-222 is increased in omental tissue from women with GDM compared to women with normoglycaemic pregnancies, and conducted elegant *in vitro* experiments to demonstrate that miR-222 potentially regulates oestrogeninduced insulin resistance during GDM. As shown in **Table 1**, many more miRNAs have been reported to exhibit altered expression in maternal blood during GDM,

Dysregulated miRNA expression has been reported in human umbilical vein endothelial cells (HUVECs) of foetuses exposed to GDM. Floris et al. reported that

however, these were investigated in single studies only.

**6. Gestational diabetes and foetal microRNA expression**

miRNAs in plasma samples of Chinese women with or without GDM [78]. Five miRNAs (miR-16, miR-17, miR-19a, miR-19b and miR-20a) were significantly upregulated in women with GDM compared to controls. Furthermore, the differential expression of these miRNAs were observed at 16–19 weeks of pregnancy, before GDM diagnosis, once again illustrating the diagnostic value of miRNAs [78]. Cao et al. similarly demonstrated increased expression of plasma miR-16, miR-17 and miR-20a in a larger cohort of Chinese women, however, they did not observe differences in the expression of miR-19a and miR-19b [79]. More recently, Pheiffer et al. reported conflicting results. The expression of all five miRNAs were decreased in South African women with GDM, however, only the decreased expression of miR-20a was statistically significant [75]. Interestingly, regression analysis showed that miR-20a was a significant predictor of GDM, while age and body mass index were not.

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

**Bio logical source**

**GDM/ controls**

67/74 (16–20, 20–24 and 24–28)

25/25 NK

*\**

**Table 1.**

11/12 (third trimester)


*\* Validated in internal (36 GDM/36 controls) and two external cohorts (16 GDM/16 controls each). GDM: gestational diabetes mellitus; qRT-PCR: quantitative real time polymerase chain reaction; NK: not known.*

#### **Table 1.**

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

**Detection method**

low density array qRT-PCR

Plasma qRT-PCR let-7e

Plasma qRT-PCR miR-155

Plasma Sequencing qRT-PCR

Plasma qRT-PCR miR-16

Sequencing qRT-PCR

Serum Taqman

**Upregulated**

Serum qRT-PCR – miR-20a

let-7 g miR-100 miR-101 miR-146a miR-8a miR-195 miR-222 miR-23b miR-30b miR-30c miR-30d miR-342 miR-423 miR-92a

miR-21

miR-16 miR-17 miR-19a miR-19b miR-20a

miR-17 miR-20a

Plasma qRT-PCR miR-330 – miR-

**Downregulated**

miR-132 miR-222

miR-222

– miR-29a

**No change**

miR-16 miR-17 miR-19a miR-19b miR-29a miR-132

– – Cel-

miR-146b miR-517 miR-222 miR-210 miR-518a miR-29a miR-223 miR-126

– – miR-221 [78]

miR-19b

548c

miR-340 – – RNU6B [93]

qRT-PCR – miR-494 – RNU6 [94]

– miR-19a

– Cel-

**Normali sation**

miR-39

CelmiR-39

miR-39

CelmiR-39 and miR-423

RNU6 [79]

miR-374 miR-320 [92]

**Ref**

[74]

[75]

[76]

[77]

**GDM/ controls**

24/24\* (16– 19 weeks gestation)

28/53 (13– 31 weeks gestation)

13/9 (23– 31 weeks gestation)

36/80 (7–23 weeks gestation)

10/10 (16– 19 weeks gestation)

85 GDM and 72 controls (16–20, 20–24 and 24–28 weeks gestation)

21/10 (24– 33 weeks gestation)

30/30 (24– 32 weeks gestation)

20/20 NK

Whole blood

Whole blood

**Bio logical source**

**90**

*Studies investigating microRNA expression in maternal blood during gestational diabetes mellitus.*

the potential of these miRNAs as screening tools for GDM. Recently, Pheiffer et al. reported that the expression of miR-29a, miR-132 and miR-222 were similarly decreased in the serum of South African women with GDM, however, only the latter was statistically significant [75]. Conflictingly, Tagoma et al. showed that miR-222 was increased in plasma of women with GDM compared to normoglycaemic pregnancies [76]. Moreover, Wander et al., observed no differences in the expression of miR-29a and miR-222 in the plasma of American women with or without GDM [77], thus illustrating the heterogeneity of miRNA expression.

In 2015, Zhu et al. used high-throughput sequencing and qRT-PCR to investigate miRNAs in plasma samples of Chinese women with or without GDM [78]. Five miRNAs (miR-16, miR-17, miR-19a, miR-19b and miR-20a) were significantly upregulated in women with GDM compared to controls. Furthermore, the differential expression of these miRNAs were observed at 16–19 weeks of pregnancy, before GDM diagnosis, once again illustrating the diagnostic value of miRNAs [78]. Cao et al. similarly demonstrated increased expression of plasma miR-16, miR-17 and miR-20a in a larger cohort of Chinese women, however, they did not observe differences in the expression of miR-19a and miR-19b [79]. More recently, Pheiffer et al. reported conflicting results. The expression of all five miRNAs were decreased in South African women with GDM, however, only the decreased expression of miR-20a was statistically significant [75]. Interestingly, regression analysis showed that miR-20a was a significant predictor of GDM, while age and body mass index were not.

Although these miRNAs were identified in plasma or serum, bioinformatics [75, 78] and experimental [74] functional analyses provided support for their biological relevance and role in the pathogenesis of GDM. Other studies also confirm the importance of miRNAs during GDM. For example, in 2014, Shi et al. reported that the expression of miR-222 is increased in omental tissue from women with GDM compared to women with normoglycaemic pregnancies, and conducted elegant *in vitro* experiments to demonstrate that miR-222 potentially regulates oestrogeninduced insulin resistance during GDM. As shown in **Table 1**, many more miRNAs have been reported to exhibit altered expression in maternal blood during GDM, however, these were investigated in single studies only.

#### **6. Gestational diabetes and foetal microRNA expression**

Dysregulated miRNA expression has been reported in human umbilical vein endothelial cells (HUVECs) of foetuses exposed to GDM. Floris et al. reported that impaired HUVEC function during GDM is associated with altered miR-101 expression [80]. Several other miRNAs, miR-137 [81], miR-let-7a, miR-let-7g, miR-30c, miR-126, miR-130b, miR-148a and miR-452 [82] were upregulated in HUVECs from infants born to mothers with GDM, suggesting that miRNAs reflect the adverse *in utero* environment imposed by GDM. Tryggestad et al. further showed that two of these miRNAs, miR-130b and miR-148a, target and decrease the expression of 5′ Adenosine monophosphate-activated protein kinase (AMPKα1), whose protein expression is decreased in placenta exposed to GDM [82]. Recently, altered miRNA expression in offspring blood was shown to be associated with birth weight [83]. MiR-33b and miR-375 were overexpressed during macrosomia, while miR-454 was overexpressed in blood of both low birth weight and macrosomic compared to normal birth weight offspring [83]. Aberrant miR-346 and miR-582 expression in cord blood were shown to be associated with foetal complications [54]. Taken together, these studies provide evidence that GDM induces dysregulated miRNA expression in offspring, which may predispose them to metabolic disease in later life. Thus, miRNAs offer potential to predict disease in offspring, which could facilitate intervention strategies to prevent future disease.

#### **7. Challenges of microRNA profiling**

Despite their stability and relative ease of quantification, analysis of circulating miRNAs present several pre-analytical and analytical challenges [84] that must be addressed before they can be used clinically. Many studies have reported that miRNA expression is affected by sample type, method of miRNA extraction, and quantification and data normalisation strategies. Differences in miRNA expression between whole blood and serum [42], between different cell types in whole blood [85, 86], between plasma and serum [87, 88] and between placenta, plasma and cord blood [54] have been described. Furthermore, miRNA expression varies according to the extraction kit used [88]. Currently, qRT-PCR is considered the gold standard for miRNA analysis, however variations between qRT-PCR platforms [87] and between qRT-PCR and other measurement platforms [22, 42, 87, 88] have been widely reported. Furthermore, data normalisation is a significant challenge during miRNA profiling, particularly extracellular miRNAs [89]. Currently, there is no consensus on the best normalisation strategy to use when profiling circulating miRNAs, although strategies based on exogenous spike-in-controls such as *C. elegans* miR-39 have been shown to be less variable than using endogenous miRNAs [88]. Moreover, heterogeneous miRNA expression is observed between populations, mediated by both genetic and environmental factors [90, 91]. During pregnancy, gestation time is also reported to affect miRNA expression [55]. Lastly, miRNAs are non-specific. For example, a single miRNA can regulate up to 200 different genes [27, 28], thus miRNAs found to be associated with GDM, may possibly be involved in other conditions as well.

#### **8. Perspectives and recommendations for future research**

MiRNAs offer great potential as biomarkers for GDM. However, they face many challenges that need to be addressed before they can become clinically applicable. Standardisation of pre-analytical and analytical methods for miRNA research may minimise the lack of reproducibility between studies and should be prioritised in miRNA research [22]. MiRNAs are epigenetic mechanisms that are regulated by various factors [90, 91], which need to be considered in miRNA studies. Large

**93**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

prospective cohort studies should be conducted to elucidate how biological, genetic and environmental factors affect miRNA expression, and to identify plausible diagnostic or prognostic candidates. Moreover, due to their non-specificity [27, 28], it is recommended that a panel of miRNAs, either alone, or in combination with other risk factors, should be used to increase the specificity of risk stratification

In this review the current status of miRNAs as biomarkers for GDM was discussed, together with recommendations for research. We provide evidence to show that miRNAs possess tremendous potential as routine screening tools, which could facilitate earlier diagnosis and management of GDM with dietary modifications or therapeutic intervention. A growing number of studies have demonstrated their clinical utility, and technological advances can lead to the development of inexpensive, point-of-care miRNA diagnostic tests in the future. However, at present miRNA profiling during GDM remains inconclusive, largely due to the irreproducibility of results between studies. Many technical, analytical and biological challenges hamper miRNA research, and must be addressed before these small RNA molecules, which are master regulators of gene expression, can become clinically

This work was funded by the South African Medical Research Council.

The authors have no conflict of interest to declare.

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

models for GDM.

**9. Conclusions**

applicable.

**Acknowledgements**

**Conflict of interest**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs DOI: http://dx.doi.org/10.5772/intechopen.82102*

prospective cohort studies should be conducted to elucidate how biological, genetic and environmental factors affect miRNA expression, and to identify plausible diagnostic or prognostic candidates. Moreover, due to their non-specificity [27, 28], it is recommended that a panel of miRNAs, either alone, or in combination with other risk factors, should be used to increase the specificity of risk stratification models for GDM.

#### **9. Conclusions**

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

tate intervention strategies to prevent future disease.

**7. Challenges of microRNA profiling**

impaired HUVEC function during GDM is associated with altered miR-101 expression [80]. Several other miRNAs, miR-137 [81], miR-let-7a, miR-let-7g, miR-30c, miR-126, miR-130b, miR-148a and miR-452 [82] were upregulated in HUVECs from infants born to mothers with GDM, suggesting that miRNAs reflect the adverse *in utero* environment imposed by GDM. Tryggestad et al. further showed that two of these miRNAs, miR-130b and miR-148a, target and decrease the expression of 5′ Adenosine monophosphate-activated protein kinase (AMPKα1), whose protein expression is decreased in placenta exposed to GDM [82]. Recently, altered miRNA expression in offspring blood was shown to be associated with birth weight [83]. MiR-33b and miR-375 were overexpressed during macrosomia, while miR-454 was overexpressed in blood of both low birth weight and macrosomic compared to normal birth weight offspring [83]. Aberrant miR-346 and miR-582 expression in cord blood were shown to be associated with foetal complications [54]. Taken together, these studies provide evidence that GDM induces dysregulated miRNA expression in offspring, which may predispose them to metabolic disease in later life. Thus, miRNAs offer potential to predict disease in offspring, which could facili-

Despite their stability and relative ease of quantification, analysis of circulating miRNAs present several pre-analytical and analytical challenges [84] that must be addressed before they can be used clinically. Many studies have reported that miRNA expression is affected by sample type, method of miRNA extraction, and quantification and data normalisation strategies. Differences in miRNA expression between whole blood and serum [42], between different cell types in whole blood [85, 86], between plasma and serum [87, 88] and between placenta, plasma and cord blood [54] have been described. Furthermore, miRNA expression varies according to the extraction kit used [88]. Currently, qRT-PCR is considered the gold standard for miRNA analysis, however variations between qRT-PCR platforms [87] and between qRT-PCR and other measurement platforms [22, 42, 87, 88] have been widely reported. Furthermore, data normalisation is a significant challenge during miRNA profiling, particularly extracellular miRNAs [89]. Currently, there is no consensus on the best normalisation strategy to use when profiling circulating miRNAs, although strategies based on exogenous spike-in-controls such as *C. elegans* miR-39 have been shown to be less variable than using endogenous miRNAs [88]. Moreover, heterogeneous miRNA expression is observed between populations, mediated by both genetic and environmental factors [90, 91]. During pregnancy, gestation time is also reported to affect miRNA expression [55]. Lastly, miRNAs are non-specific. For example, a single miRNA can regulate up to 200 different genes [27, 28], thus miRNAs found to be associated with GDM, may possibly be involved

**92**

in other conditions as well.

**8. Perspectives and recommendations for future research**

MiRNAs offer great potential as biomarkers for GDM. However, they face many challenges that need to be addressed before they can become clinically applicable. Standardisation of pre-analytical and analytical methods for miRNA research may minimise the lack of reproducibility between studies and should be prioritised in miRNA research [22]. MiRNAs are epigenetic mechanisms that are regulated by various factors [90, 91], which need to be considered in miRNA studies. Large

In this review the current status of miRNAs as biomarkers for GDM was discussed, together with recommendations for research. We provide evidence to show that miRNAs possess tremendous potential as routine screening tools, which could facilitate earlier diagnosis and management of GDM with dietary modifications or therapeutic intervention. A growing number of studies have demonstrated their clinical utility, and technological advances can lead to the development of inexpensive, point-of-care miRNA diagnostic tests in the future. However, at present miRNA profiling during GDM remains inconclusive, largely due to the irreproducibility of results between studies. Many technical, analytical and biological challenges hamper miRNA research, and must be addressed before these small RNA molecules, which are master regulators of gene expression, can become clinically applicable.

#### **Acknowledgements**

This work was funded by the South African Medical Research Council.

### **Conflict of interest**

The authors have no conflict of interest to declare.

#### **Author details**

Carmen Pheiffer1,2\*, Stephanie Dias1,3, Paul Rheeder4 and Sumaiya Adam3

1 Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg, South Africa

2 Division of Medical Physiology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Tygerberg, South Africa

3 Department of Obstetrics and Gynaecology, University of Pretoria, Pretoria, South Africa

4 Department of Internal Medicine, University of Pretoria, Pretoria, South Africa

\*Address all correspondence to: carmen.pheiffer@mrc.ac.za

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**95**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

screening and diagnosis of gestational diabetes mellitus results in improved pregnancy outcomes at a lower cost in a large cohort of pregnant women: The St. Carlos Gestational Diabetes Study. Diabetes Care. 2014;**37**:2442-2450. DOI:

10.2337/dc14-0179

dc13-2411

10.7573/dic.212282

[9] Hernandez TL, Van Pelt RE, Anderson MA, Daniels LJ, West NA, Donahoo WT, et al. A higher-complex carbohydrate diet in gestational diabetes mellitus achieves glucose targets and lowers postprandial lipids: A randomized crossover study. Diabetes Care. 2014;**37**:1254-1262. DOI: 10.2337/

[10] Kelley KW, Carroll DG, Meyer A. A review of current treatment strategies for gestational diabetes mellitus. Drugs in Context. 2015;**4**:212282. DOI:

[11] Santangelo C, Zicari A, Mandosi E, Scazzocchio B, Mari E, Morano S, et al. Could gestational diabetes mellitus be managed through dietary bioactive compounds? Current knowledge and future perspectives. British Journal of Nutrition. 2016;**115**:1129-1144. DOI:

10.1017/S0007114516000222

of Diabetes Mellitus and its

Organization; 1999

pone.0087863

[12] World Health Organization.

Definition, Diagnosis and Classification

Complications. Geneva: World Health

[13] Xu Y, Shen S, Sun L, Yang H, Jin B, Cao X. Metabolic syndrome risk after gestational diabetes: A systematic review and meta-analysis. PLoS One. 2014;**9**:e87863. DOI: 10.1371/journal.

[14] Li J-W, He S-Y, Liu P, Luo L, Zhao L, Xiao Y-B. Association of gestational

subclinical atherosclerosis: A systemic review and meta-analysis. BMC

diabetes mellitus (GDM) with

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

[1] Ferrara A. Increasing prevalence of gestational diabetes mellitus. Diabetes Care. 2007;**30**:S141-S146. DOI: 10.2337/

[2] International Diabetes Federation. IDF Diabetes Atlas. 8th ed. Brussels, Belgium: International Diabetes Federation; 2017. http://www.

[3] Agarwal MM. Gestational diabetes mellitus: Screening with fasting plasma glucose. World Journal of Diabetes. 2016;**7**:279-289. DOI: 10.4239/wjd.

[4] Bellamy L, Casas J-P, Hingorani AD, Williams D. Type 2 diabetes mellitus after gestational diabetes: A systematic review and meta-analysis. Lancet. 2009;**373**:1773-1779. DOI: 10.1016/

S0140-6736(09)60731-5

bpobgyn.2014.08.004

dc07-s223

[5] Mitanchez D, Yzydorczyk C, Siddeek B, Boubred F, Benahmed M, Simeoni U. The offspring of the diabetic mother—Short- and long-term implications. Best Practice & Research. Clinical Obstetrics & Gynaecology. 2015;**29**:256-269. DOI: 10.1016/j.

[6] Ratner RE. Prevention of type 2 diabetes in women with previous gestational diabetes. Diabetes Care. 2007;**30**:S242-S245. DOI: 10.2337/

[7] Falavigna M, Schmidt MI, Trujillo J, Alves LF, Wendland ER, Torloni MR, et al. Effectiveness of gestational diabetes treatment: A systematic review with quality of evidence assessment. Diabetes Research and Clinical Practice.

2012;**98**:396-405. DOI: 10.1016/j.

[8] Duran A, Sáenz S, Torrejón MJ, Bordiú E, Del Valle L, Galindo M, et al. Introduction of IADPSG criteria for the

diabres.2012.09.002

**References**

dc07-s206

diabetesatlas.org

v7.i14.279

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs DOI: http://dx.doi.org/10.5772/intechopen.82102*

#### **References**

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

1 Biomedical Research and Innovation Platform, South African Medical Research

2 Division of Medical Physiology, Faculty of Medicine and Health Sciences,

3 Department of Obstetrics and Gynaecology, University of Pretoria, Pretoria,

4 Department of Internal Medicine, University of Pretoria, Pretoria, South Africa

and Sumaiya Adam3

**94**

**Author details**

South Africa

Council, Tygerberg, South Africa

provided the original work is properly cited.

Carmen Pheiffer1,2\*, Stephanie Dias1,3, Paul Rheeder4

University of Stellenbosch, Tygerberg, South Africa

\*Address all correspondence to: carmen.pheiffer@mrc.ac.za

[1] Ferrara A. Increasing prevalence of gestational diabetes mellitus. Diabetes Care. 2007;**30**:S141-S146. DOI: 10.2337/ dc07-s206

[2] International Diabetes Federation. IDF Diabetes Atlas. 8th ed. Brussels, Belgium: International Diabetes Federation; 2017. http://www. diabetesatlas.org

[3] Agarwal MM. Gestational diabetes mellitus: Screening with fasting plasma glucose. World Journal of Diabetes. 2016;**7**:279-289. DOI: 10.4239/wjd. v7.i14.279

[4] Bellamy L, Casas J-P, Hingorani AD, Williams D. Type 2 diabetes mellitus after gestational diabetes: A systematic review and meta-analysis. Lancet. 2009;**373**:1773-1779. DOI: 10.1016/ S0140-6736(09)60731-5

[5] Mitanchez D, Yzydorczyk C, Siddeek B, Boubred F, Benahmed M, Simeoni U. The offspring of the diabetic mother—Short- and long-term implications. Best Practice & Research. Clinical Obstetrics & Gynaecology. 2015;**29**:256-269. DOI: 10.1016/j. bpobgyn.2014.08.004

[6] Ratner RE. Prevention of type 2 diabetes in women with previous gestational diabetes. Diabetes Care. 2007;**30**:S242-S245. DOI: 10.2337/ dc07-s223

[7] Falavigna M, Schmidt MI, Trujillo J, Alves LF, Wendland ER, Torloni MR, et al. Effectiveness of gestational diabetes treatment: A systematic review with quality of evidence assessment. Diabetes Research and Clinical Practice. 2012;**98**:396-405. DOI: 10.1016/j. diabres.2012.09.002

[8] Duran A, Sáenz S, Torrejón MJ, Bordiú E, Del Valle L, Galindo M, et al. Introduction of IADPSG criteria for the screening and diagnosis of gestational diabetes mellitus results in improved pregnancy outcomes at a lower cost in a large cohort of pregnant women: The St. Carlos Gestational Diabetes Study. Diabetes Care. 2014;**37**:2442-2450. DOI: 10.2337/dc14-0179

[9] Hernandez TL, Van Pelt RE, Anderson MA, Daniels LJ, West NA, Donahoo WT, et al. A higher-complex carbohydrate diet in gestational diabetes mellitus achieves glucose targets and lowers postprandial lipids: A randomized crossover study. Diabetes Care. 2014;**37**:1254-1262. DOI: 10.2337/ dc13-2411

[10] Kelley KW, Carroll DG, Meyer A. A review of current treatment strategies for gestational diabetes mellitus. Drugs in Context. 2015;**4**:212282. DOI: 10.7573/dic.212282

[11] Santangelo C, Zicari A, Mandosi E, Scazzocchio B, Mari E, Morano S, et al. Could gestational diabetes mellitus be managed through dietary bioactive compounds? Current knowledge and future perspectives. British Journal of Nutrition. 2016;**115**:1129-1144. DOI: 10.1017/S0007114516000222

[12] World Health Organization. Definition, Diagnosis and Classification of Diabetes Mellitus and its Complications. Geneva: World Health Organization; 1999

[13] Xu Y, Shen S, Sun L, Yang H, Jin B, Cao X. Metabolic syndrome risk after gestational diabetes: A systematic review and meta-analysis. PLoS One. 2014;**9**:e87863. DOI: 10.1371/journal. pone.0087863

[14] Li J-W, He S-Y, Liu P, Luo L, Zhao L, Xiao Y-B. Association of gestational diabetes mellitus (GDM) with subclinical atherosclerosis: A systemic review and meta-analysis. BMC

Cardiovascular Disorders. 2014;**14**:132. DOI: 10.1186/1471-2261-14-132

[15] Park YM, O'Brien KM, Zhao S, Weinberg CR, Baird DD, Sandler DP. Gestational diabetes mellitus may be associated with increased risk of breast cancer. British Journal of Cancer. 2017;**116**:960-963. DOI: 10.1038/ bjc.2017.34

[16] Silveira PP, Portella AK, Goldani MZ, Barbieri MA. Developmental origins of health and disease (DOHaD). The Journal of Pediatrics. 2007;**83**:494-504. DOI: 10.2223/JPED.1728

[17] Barker DJ. Maternal nutrition, fetal nutrition, and disease in later life. Nutrition. 1997;**13**:807-813

[18] Chu SY, Callaghan WM, Kim SY, Schmid CH, Lau J, England LJ, et al. Maternal obesity and risk of gestational diabetes mellitus. Diabetes Care. 2007;**30**:2070-2076. DOI: 10.2337/ dc06-2559a

[19] Adam S, Pheiffer C, Dias S, Rheeder P. Association between gestational diabetes and biomarkers: A role in diagnosis. Biomarkers. 2018;**23**:386-391. DOI: 10.1080/1354750X.2018.1432690

[20] Cosson E, Benbara A, Pharisien I, Nguyen MT, Revaux A, Lormeau B, et al. Diagnostic and prognostic performances over 9 years of a selective screening strategy for gestational diabetes mellitus in a cohort of 18,775 subjects. Diabetes Care. 2013;**36**:598-603. DOI: 10.2337/ dc12-1428

[21] Hulka B. Overview of biological markers. In: Hulka BS, Griffith JD, Wilcosky TC, editors. Biological Markers in Epidemiology. New York: Oxford University Press; 1990. pp. 3-15

[22] Etheridge A, Lee I, Hood L, Galas D, Wang K. Extracellular microRNA: A new source of biomarkers. Mutation Research. 2011;**717**:85-90. DOI: 10.1016/j.mrfmmm.2011.03.004

[23] Guay C, Roggli E, Nesca V, Jacovetti C, Regazzi R. Diabetes mellitus, a microRNA-related disease? Translational Research. 2011;**157**:253- 264. DOI: 10.1016/j.trsl.2011.01.009

[24] Lee RC, Feinbaum RL, Ambros V. The *C. elegans* heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14. Cell. 1993;**75**:843-854

[25] Bartel DP. MicroRNAs: Genomics, biogenesis, mechanism, and function. Cell. 2004;**116**:281-297

[26] Guo H, Ingolia NT, Weissman JS, Bartel DP. Mammalian microRNAs predominantly act to decrease target mRNA levels. Nature. 2010;**466**:835- 840. DOI: 10.1038/nature09267

[27] Krek A, Grün D, Poy MN, Wolf R, Rosenberg L, Epstein EJ, et al. Combinatorial microRNA target predictions. Nature Genetics. 2005;**37**:495-500. DOI: 10.1038/ng1536

[28] Lewis BP, Burge CB, Bartel DP. Conserved seed pairing, often flanked by adenosines, indicates that thousands of human genes are microRNA targets. Cell. 2005;**120**:15-20. DOI: 10.1016/j.cell.2004.12.035

[29] Friedman RC, Farh KK-H, Burge CB, Bartel DP. Most mammalian mRNAs are conserved targets of microRNAs. Genome Research. 2009;**19**:92-105. DOI: 10.1101/gr.082701.108

[30] Ardekani AM, Naeini MM. The role of MicroRNAs in human diseases. Avicenna Journal of Medical Biotechnology. 2010;**2**:161-179

[31] Regazzi R. MicroRNAs as therapeutic targets for the treatment of diabetes mellitus and its complications. Expert Opinion on Therapeutic

**97**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

Circulation Research. 2010;**107**:810-817. DOI: 10.1161/CIRCRESAHA.110.226357

[40] Zampetaki A, Mayr M. MicroRNAs in vascular and metabolic disease. Circulation Research. 2012;**110**:508-522. DOI: 10.1161/CIRCRESAHA.111.247445

[41] Karolina DS, Armugam A, Tavintharan S, Wong MT, Lim SC, Sum CF, et al. MicroRNA 144 impairs insulin signaling by inhibiting the expression of insulin receptor substrate 1 in type 2 diabetes mellitus. PLoS One. 2011;**6**:e22839. DOI: 10.1371/journal.

[42] Dias HS, Muller C, Louw J, Pheiffer C. MicroRNA expression varies according to glucose tolerance,

measurement platform, and biological source. BioMed Research International. 2017;**2017**:1080157. DOI:

[43] Pheiffer C, Dias S, Willmer T, Pace R, Aagaard K, Louw J. Altered microRNA expression during impaired glucose tolerance and high-fat diet feeding. Experimental and Clinical Endocrinology & Diabetes. 11 Jun 2018. DOI: 10.1055/a-0619-4576. [Epub ahead

[44] Párrizas M, Brugnara L, Esteban Y, González-Franquesa A, Canivell S, Murillo S, et al. Circulating miR-192 and miR-193b are markers of prediabetes and are modulated by an exercise intervention. The Journal of Clinical Endocrinology and Metabolism. 2015;**100**:E407-E415. DOI: 10.1210/

[45] Luo M, Li R, Deng X, Ren M, Chen N, Zeng M, et al. Platelet-derived miR-103b as a novel biomarker for the early diagnosis of type 2 diabetes. Acta Diabetologica. 2015;**52**:943-949. DOI:

10.1007/s00592-015-0733-0

[46] Cai M, Kolluru GK, Ahmed A. Small molecule, big prospects:

10.1155/2017/1080157

of print]

jc.2014-2574

pone.0022839

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

Targets. 2018;**22**:153-160. DOI: 10.1080/14728222.2018.1420168

[32] Creemers EE, Tijsen AJ, Pinto YM. Circulating microRNAs: Novel biomarkers and extracellular communicators in cardiovascular disease? Circulation Research. 2012;**110**:483-495. DOI: 10.1161/ CIRCRESAHA.111.247452

[33] Guay C, Regazzi R. Exosomes as new players in metabolic organ crosstalk. Diabetes, Obesity & Metabolism. 2017;**19**:S137-S146. DOI: 10.1111/

[34] Turchinovich A, Weiz L, Burwinkel B. Extracellular miRNAs: The mystery of their origin and function. Trends in Biochemical Sciences. 2012;**37**:460-465.

[35] Guay C, Regazzi R. New emerging tasks for microRNAs in the control of β-cell activities. Biochimica et Biophysica Acta. 2016;**1861**:2121-2129. DOI: 10.1016/j.bbalip.2016.05.003

DOI: 10.1016/j.tibs.2012.08.003

[36] Jung M, Schaefer A, Steiner I, Kempkensteffen C, Stephan C,

Erbersdobler A, et al. Robust microRNA stability in degraded RNA preparations from human tissue and cell samples. Clinical Chemistry. 2010;**56**:998-1006. DOI: 10.1373/clinchem.2009.141580

[37] Pritchard CC, Cheng HH, Tewari M. MicroRNA profiling: Approaches and considerations. Nature Reviews. Genetics. 2012;**13**:358-369. DOI:

[38] Mayeux R. Biomarkers: Potential uses and limitations. NeuroRx. 2004;**1**:182-188. DOI: 10.1602/

[39] Zampetaki A, Kiechl S, Drozdov I, Willeit P, Mayr U, Prokopi M, et al. Plasma microRNA profiling reveals loss of endothelial miR-126 and other microRNAs in type 2 diabetes.

10.1038/nrg3198

neurorx.1.2.182

dom.13027

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs DOI: http://dx.doi.org/10.5772/intechopen.82102*

Targets. 2018;**22**:153-160. DOI: 10.1080/14728222.2018.1420168

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

Research. 2011;**717**:85-90. DOI: 10.1016/j.mrfmmm.2011.03.004

[23] Guay C, Roggli E, Nesca V, Jacovetti C, Regazzi R. Diabetes mellitus, a microRNA-related disease? Translational Research. 2011;**157**:253- 264. DOI: 10.1016/j.trsl.2011.01.009

[24] Lee RC, Feinbaum RL, Ambros V. The *C. elegans* heterochronic gene lin-4 encodes small RNAs with antisense

complementarity to lin-14. Cell.

[25] Bartel DP. MicroRNAs: Genomics, biogenesis, mechanism, and function.

[26] Guo H, Ingolia NT, Weissman JS, Bartel DP. Mammalian microRNAs predominantly act to decrease target mRNA levels. Nature. 2010;**466**:835- 840. DOI: 10.1038/nature09267

[27] Krek A, Grün D, Poy MN, Wolf R, Rosenberg L, Epstein EJ, et al. Combinatorial microRNA target predictions. Nature Genetics. 2005;**37**:495-500. DOI: 10.1038/ng1536

[28] Lewis BP, Burge CB, Bartel DP. Conserved seed pairing, often flanked by adenosines, indicates that thousands of human genes are microRNA targets. Cell. 2005;**120**:15-20.

DOI: 10.1016/j.cell.2004.12.035

10.1101/gr.082701.108

[29] Friedman RC, Farh KK-H, Burge CB, Bartel DP. Most mammalian mRNAs are conserved targets of microRNAs. Genome Research. 2009;**19**:92-105. DOI:

[30] Ardekani AM, Naeini MM. The role of MicroRNAs in human

diseases. Avicenna Journal of Medical

therapeutic targets for the treatment of diabetes mellitus and its complications.

Biotechnology. 2010;**2**:161-179

[31] Regazzi R. MicroRNAs as

Expert Opinion on Therapeutic

1993;**75**:843-854

Cell. 2004;**116**:281-297

Cardiovascular Disorders. 2014;**14**:132.

DOI: 10.1186/1471-2261-14-132

[15] Park YM, O'Brien KM, Zhao S, Weinberg CR, Baird DD, Sandler DP. Gestational diabetes mellitus may be associated with increased risk of breast cancer. British Journal of Cancer.

2017;**116**:960-963. DOI: 10.1038/

[17] Barker DJ. Maternal nutrition, fetal nutrition, and disease in later life.

[18] Chu SY, Callaghan WM, Kim SY, Schmid CH, Lau J, England LJ, et al. Maternal obesity and risk of gestational diabetes mellitus. Diabetes Care. 2007;**30**:2070-2076. DOI: 10.2337/

[19] Adam S, Pheiffer C, Dias S, Rheeder P. Association between gestational diabetes and biomarkers: A role in diagnosis. Biomarkers. 2018;**23**:386-391. DOI: 10.1080/1354750X.2018.1432690

[20] Cosson E, Benbara A, Pharisien I, Nguyen MT, Revaux A, Lormeau B, et al. Diagnostic and prognostic performances over 9 years of a selective screening strategy for gestational diabetes mellitus in a cohort of 18,775 subjects. Diabetes Care. 2013;**36**:598-603. DOI: 10.2337/

[21] Hulka B. Overview of biological markers. In: Hulka BS, Griffith JD, Wilcosky TC, editors. Biological Markers in Epidemiology. New York: Oxford University Press; 1990. pp. 3-15

[22] Etheridge A, Lee I, Hood L, Galas D, Wang K. Extracellular microRNA: A new source of biomarkers. Mutation

DOI: 10.2223/JPED.1728

Nutrition. 1997;**13**:807-813

[16] Silveira PP, Portella AK, Goldani MZ, Barbieri MA. Developmental origins of health and disease (DOHaD). The Journal of Pediatrics. 2007;**83**:494-504.

bjc.2017.34

dc06-2559a

dc12-1428

**96**

[32] Creemers EE, Tijsen AJ, Pinto YM. Circulating microRNAs: Novel biomarkers and extracellular communicators in cardiovascular disease? Circulation Research. 2012;**110**:483-495. DOI: 10.1161/ CIRCRESAHA.111.247452

[33] Guay C, Regazzi R. Exosomes as new players in metabolic organ crosstalk. Diabetes, Obesity & Metabolism. 2017;**19**:S137-S146. DOI: 10.1111/ dom.13027

[34] Turchinovich A, Weiz L, Burwinkel B. Extracellular miRNAs: The mystery of their origin and function. Trends in Biochemical Sciences. 2012;**37**:460-465. DOI: 10.1016/j.tibs.2012.08.003

[35] Guay C, Regazzi R. New emerging tasks for microRNAs in the control of β-cell activities. Biochimica et Biophysica Acta. 2016;**1861**:2121-2129. DOI: 10.1016/j.bbalip.2016.05.003

[36] Jung M, Schaefer A, Steiner I, Kempkensteffen C, Stephan C, Erbersdobler A, et al. Robust microRNA stability in degraded RNA preparations from human tissue and cell samples. Clinical Chemistry. 2010;**56**:998-1006. DOI: 10.1373/clinchem.2009.141580

[37] Pritchard CC, Cheng HH, Tewari M. MicroRNA profiling: Approaches and considerations. Nature Reviews. Genetics. 2012;**13**:358-369. DOI: 10.1038/nrg3198

[38] Mayeux R. Biomarkers: Potential uses and limitations. NeuroRx. 2004;**1**:182-188. DOI: 10.1602/ neurorx.1.2.182

[39] Zampetaki A, Kiechl S, Drozdov I, Willeit P, Mayr U, Prokopi M, et al. Plasma microRNA profiling reveals loss of endothelial miR-126 and other microRNAs in type 2 diabetes.

Circulation Research. 2010;**107**:810-817. DOI: 10.1161/CIRCRESAHA.110.226357

[40] Zampetaki A, Mayr M. MicroRNAs in vascular and metabolic disease. Circulation Research. 2012;**110**:508-522. DOI: 10.1161/CIRCRESAHA.111.247445

[41] Karolina DS, Armugam A, Tavintharan S, Wong MT, Lim SC, Sum CF, et al. MicroRNA 144 impairs insulin signaling by inhibiting the expression of insulin receptor substrate 1 in type 2 diabetes mellitus. PLoS One. 2011;**6**:e22839. DOI: 10.1371/journal. pone.0022839

[42] Dias HS, Muller C, Louw J, Pheiffer C. MicroRNA expression varies according to glucose tolerance, measurement platform, and biological source. BioMed Research International. 2017;**2017**:1080157. DOI: 10.1155/2017/1080157

[43] Pheiffer C, Dias S, Willmer T, Pace R, Aagaard K, Louw J. Altered microRNA expression during impaired glucose tolerance and high-fat diet feeding. Experimental and Clinical Endocrinology & Diabetes. 11 Jun 2018. DOI: 10.1055/a-0619-4576. [Epub ahead of print]

[44] Párrizas M, Brugnara L, Esteban Y, González-Franquesa A, Canivell S, Murillo S, et al. Circulating miR-192 and miR-193b are markers of prediabetes and are modulated by an exercise intervention. The Journal of Clinical Endocrinology and Metabolism. 2015;**100**:E407-E415. DOI: 10.1210/ jc.2014-2574

[45] Luo M, Li R, Deng X, Ren M, Chen N, Zeng M, et al. Platelet-derived miR-103b as a novel biomarker for the early diagnosis of type 2 diabetes. Acta Diabetologica. 2015;**52**:943-949. DOI: 10.1007/s00592-015-0733-0

[46] Cai M, Kolluru GK, Ahmed A. Small molecule, big prospects: MicroRNA in pregnancy and its complications. Journal of Pregnancy. 2017;**2017**:6972732. DOI: 10.1155/2017/6972732

[47] Poirier C, Desgagné V, Guérin R, Bouchard L. MicroRNAs in pregnancy and gestational diabetes mellitus: Emerging role in maternal metabolic regulation. Current Diabetes Reports. 2017;**17**:35. DOI: 10.1007/ s11892-017-0856-5

[48] Pineles BL, Romero R, Montenegro D, Tarca AL, Han YM, Kim YM, et al. Distinct subsets of microRNAs are expressed differentially in the human placentas of patients with preeclampsia. American Journal of Obstetrics and Gynecology. 2007;**196**:261.e1-261.e6. DOI: 10.1016/j.ajog.2007.01.008

[49] Zhu X, Han T, Sargent IL, Yin G, Yao Y. Differential expression profile of microRNAs in human placentas from preeclamptic pregnancies vs normal pregnancies. American Journal of Obstetrics and Gynecology. 2009;**200**:661.e1-661.e7. DOI: 10.1016/j. ajog.2008.12.045

[50] Hu Y, Li P, Hao S, Liu L, Zhao J, Hou Y. Differential expression of microRNAs in the placentae of Chinese patients with severe pre-eclampsia. Clinical Chemistry and Laboratory Medicine. 2009;**47**:923-929. DOI: 10.1515/ CCLM.2009.228

[51] Wang W, Feng L, Zhang H, Hachy S, Satohisa S, Laurent LC, et al. Preeclampsia up-regulates angiogenesisassociated MicroRNA (i.e., miR-17, -20a, and -20b) that target Ephrin-B2 and EPHB4 in human placenta. The Journal of Clinical Endocrinology and Metabolism. 2012;**97**:E1051-E1059. DOI: 10.1210/jc.2011-3131.

[52] Niu Z-R, Han T, Sun X-L, Luan L-X, Gou W-L, Zhu X-M. MicroRNA-30a-3p is overexpressed in the placentas of patients with preeclampsia and affects

trophoblast invasion and apoptosis by its effects on IGF-1. American Journal of Obstetrics and Gynecology. 2018;**218**:249.e1-249.e12. DOI: 10.1016/j. ajog.2017.11.568

[53] Li J, Chen L, Tang Q, Wu W, Gu H, Liu L, et al. The role, mechanism and potentially novel biomarker of microRNA-17-92 cluster in macrosomia. Scientific Reports. 2015;**5**:17212. DOI: 10.1038/srep17212

[54] Tsai P-Y, Li S-H, Chen W-N, Tsai H-L, Su M-T. Differential miR-346 and miR-582-3p expression in association with selected maternal and fetal complications. International Journal of Molecular Sciences. 2017;**18.pii**:E1570. DOI: 10.3390/ijms18071570

[55] Chim SS, Shing TK, Hung EC, Leung T-Y, Lau T-K, Chiu RW, et al. Detection and characterization of placental microRNAs in maternal plasma. Clinical Chemistry. 2008;**54**:482-490. DOI: 10.1373/ clinchem.2007.097972

[56] Luo S-S, Ishibashi O, Ishikawa G, Ishikawa T, Katayama A, Mishima T, et al. Human villous trophoblasts express and secrete placenta-specific microRNAs into maternal circulation via exosomes. Biology of Reproduction. 2009;**81**:717-729. DOI: 10.1095/ biolreprod.108.075481

[57] Miura K, Morisaki S, Abe S, Higashijima A, Hasegawa Y, Miura S, et al. Circulating levels of maternal plasma cell-free pregnancy-associated placenta-specific microRNAs are associated with placental weight. Placenta. 2014;**35**:848-851. DOI: 10.1016/j.placenta.2014.06.002

[58] Hasegawa Y, Miura K, Higashijima A, Abe S, Miura S, Yoshiura K, et al. Increased levels of cell-free miR-517a and decreased levels of cell-free miR-518b in maternal plasma samples from placenta previa pregnancies at

**99**

jog.12749

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

International. 2014;**2014**:394125. DOI:

[66] Collares CV, Evangelista AF, Xavier DJ, Rassi DM, Arns T, Foss-Freitas MC, et al. Identifying common and specific microRNAs expressed in peripheral blood mononuclear cell of type 1, type 2, and gestational diabetes mellitus patients. BMC Research Notes. 2013;**6**:491. DOI:

[65] Ge Q, Zhu Y, Li H, Tian F, Xie X, Bai Y. Differential expression of circulating miRNAs in maternal plasma in pregnancies with fetal macrosomia. International Journal of Molecular Medicine. 2015;**35**:81-91. DOI: 10.3892/

10.1155/2014/394125

ijmm.2014.1989

10.1186/1756-0500-6-491

10.3892/mmr.2014.2058

[68] Abbott BD. Review of the

2009;**27**:246-257. DOI: 10.1016/j.

[69] Pawlak M, Lefebvre P, Staels B. Molecular mechanism of PPARα action and its impact on lipid

DOI: 10.1016/j.jhep.2014.10.039

[70] Li J, Song L, Zhou L, Wu J, Sheng C, Chen H, et al. A microRNA signature in gestational diabetes mellitus associated with risk of macrosomia. Cellular Physiology and Biochemistry. 2015;**37**:243-252. DOI:

10.1159/000430349

metabolism, inflammation and fibrosis in non-alcoholic fatty liver disease. Journal of Hepatology. 2015;**62**:720-733.

reprotox.2008.10.001

expression of peroxisome proliferatoractivated receptors alpha (PPAR alpha), beta (PPAR beta), and gamma (PPAR gamma) in rodent and human development. Reproductive Toxicology.

[67] Zhao C, Zhang T, Shi Z, Ding H, Ling X. MicroRNA-518d regulates PPARα protein expression in the placentas of females with gestational diabetes mellitus. Molecular Medicine Reports. 2014;**9**:2085-2090. DOI:

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

32 weeks of gestation. Reproductive Sciences. 2015;**22**:1569-1576. DOI:

[60] Hromadnikova I, Kotlabova K, Ondrackova M, Kestlerova A, Novotna V, Hympanova L, et al. Circulating C19MC microRNAs in preeclampsia, gestational hypertension, and fetal growth restriction. Mediators of Inflammation. 2013;**2013**:186041. DOI:

[61] Hromadnikova I, Kotlabova K, Ivankova K, Krofta L. First trimester screening of circulating C19MC microRNAs and the evaluation of their potential to predict the onset of preeclampsia and IUGR. PLoS One. 2017;**12**:e0171756. DOI: 10.1371/journal.

[62] Jiang H, Wen Y, Hu L, Miao T, Zhang M, Dong J. Serum microRNAs as diagnostic biomarkers for macrosomia. Reproductive Sciences. 2015;**22**:664-671.

DOI: 10.1177/1933719114561557

[63] Miura K, Higashijima A, Murakami Y, Tsukamoto O,

[64] Hu L, Han J, Zheng F, Ma H, Chen J, Jiang Y, et al. Early secondtrimester serum microRNAs as potential biomarker for nondiabetic macrosomia. BioMed Research

Hasegawa Y, Abe S, et al. Circulating chromosome 19 miRNA cluster microRNAs in pregnant women with severe pre-eclampsia. The Journal of Obstetrics and Gynaecology Research. 2015;**41**:1526-1532. DOI: 10.1111/

10.1155/2013/186041

pone.0171756

10.1177/1933719115589407

[59] Miura K, Higashijima A, Murakami Y, Fuchi N, Tsukamoto O, Abe S, et al. Circulating levels of pregnancy-associated, placenta-specific microRNAs in pregnant women with placental abruption. Reproductive Sciences. 2017;**24**:148-155. DOI: 10.1177/1933719116653837

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs DOI: http://dx.doi.org/10.5772/intechopen.82102*

32 weeks of gestation. Reproductive Sciences. 2015;**22**:1569-1576. DOI: 10.1177/1933719115589407

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

trophoblast invasion and apoptosis by its effects on IGF-1. American Journal of Obstetrics and Gynecology. 2018;**218**:249.e1-249.e12. DOI: 10.1016/j.

[53] Li J, Chen L, Tang Q, Wu W, Gu H, Liu L, et al. The role, mechanism and potentially novel biomarker of microRNA-17-92 cluster in macrosomia. Scientific Reports. 2015;**5**:17212. DOI:

[54] Tsai P-Y, Li S-H, Chen W-N, Tsai H-L, Su M-T. Differential miR-346 and miR-582-3p expression in association with selected maternal and fetal complications. International Journal of Molecular Sciences. 2017;**18.pii**:E1570.

DOI: 10.3390/ijms18071570

clinchem.2007.097972

[55] Chim SS, Shing TK, Hung EC, Leung T-Y, Lau T-K, Chiu RW, et al. Detection and characterization of placental microRNAs in maternal plasma. Clinical Chemistry. 2008;**54**:482-490. DOI: 10.1373/

[56] Luo S-S, Ishibashi O, Ishikawa G, Ishikawa T, Katayama A, Mishima T, et al. Human villous trophoblasts express and secrete placenta-specific microRNAs into maternal circulation via exosomes. Biology of Reproduction.

2009;**81**:717-729. DOI: 10.1095/

[57] Miura K, Morisaki S, Abe S, Higashijima A, Hasegawa Y, Miura S, et al. Circulating levels of maternal plasma cell-free pregnancy-associated placenta-specific microRNAs are associated with placental weight. Placenta. 2014;**35**:848-851. DOI: 10.1016/j.placenta.2014.06.002

[58] Hasegawa Y, Miura K, Higashijima A, Abe S, Miura S, Yoshiura K, et al. Increased levels of cell-free miR-517a and decreased levels of cell-free miR-518b in maternal plasma samples from placenta previa pregnancies at

biolreprod.108.075481

ajog.2017.11.568

10.1038/srep17212

MicroRNA in pregnancy and its complications. Journal of

10.1155/2017/6972732

s11892-017-0856-5

ajog.2008.12.045

CCLM.2009.228

10.1210/jc.2011-3131.

[51] Wang W, Feng L, Zhang H, Hachy S, Satohisa S, Laurent LC, et al. Preeclampsia up-regulates angiogenesisassociated MicroRNA (i.e., miR-17, -20a, and -20b) that target Ephrin-B2 and EPHB4 in human placenta. The Journal of Clinical Endocrinology and Metabolism. 2012;**97**:E1051-E1059. DOI:

[52] Niu Z-R, Han T, Sun X-L, Luan L-X, Gou W-L, Zhu X-M. MicroRNA-30a-3p is overexpressed in the placentas of patients with preeclampsia and affects

Pregnancy. 2017;**2017**:6972732. DOI:

[47] Poirier C, Desgagné V, Guérin R, Bouchard L. MicroRNAs in pregnancy and gestational diabetes mellitus: Emerging role in maternal metabolic regulation. Current Diabetes Reports. 2017;**17**:35. DOI: 10.1007/

[48] Pineles BL, Romero R, Montenegro D, Tarca AL, Han YM, Kim YM, et al. Distinct subsets of microRNAs are expressed differentially in the human placentas of patients with preeclampsia. American Journal of Obstetrics and Gynecology. 2007;**196**:261.e1-261.e6. DOI: 10.1016/j.ajog.2007.01.008

[49] Zhu X, Han T, Sargent IL, Yin G, Yao Y. Differential expression profile of microRNAs in human placentas from preeclamptic pregnancies vs normal pregnancies. American Journal of Obstetrics and Gynecology. 2009;**200**:661.e1-661.e7. DOI: 10.1016/j.

[50] Hu Y, Li P, Hao S, Liu L, Zhao J, Hou Y. Differential expression of microRNAs in the placentae of Chinese patients with severe pre-eclampsia. Clinical Chemistry and Laboratory Medicine. 2009;**47**:923-929. DOI: 10.1515/

**98**

[59] Miura K, Higashijima A, Murakami Y, Fuchi N, Tsukamoto O, Abe S, et al. Circulating levels of pregnancy-associated, placenta-specific microRNAs in pregnant women with placental abruption. Reproductive Sciences. 2017;**24**:148-155. DOI: 10.1177/1933719116653837

[60] Hromadnikova I, Kotlabova K, Ondrackova M, Kestlerova A, Novotna V, Hympanova L, et al. Circulating C19MC microRNAs in preeclampsia, gestational hypertension, and fetal growth restriction. Mediators of Inflammation. 2013;**2013**:186041. DOI: 10.1155/2013/186041

[61] Hromadnikova I, Kotlabova K, Ivankova K, Krofta L. First trimester screening of circulating C19MC microRNAs and the evaluation of their potential to predict the onset of preeclampsia and IUGR. PLoS One. 2017;**12**:e0171756. DOI: 10.1371/journal. pone.0171756

[62] Jiang H, Wen Y, Hu L, Miao T, Zhang M, Dong J. Serum microRNAs as diagnostic biomarkers for macrosomia. Reproductive Sciences. 2015;**22**:664-671. DOI: 10.1177/1933719114561557

[63] Miura K, Higashijima A, Murakami Y, Tsukamoto O, Hasegawa Y, Abe S, et al. Circulating chromosome 19 miRNA cluster microRNAs in pregnant women with severe pre-eclampsia. The Journal of Obstetrics and Gynaecology Research. 2015;**41**:1526-1532. DOI: 10.1111/ jog.12749

[64] Hu L, Han J, Zheng F, Ma H, Chen J, Jiang Y, et al. Early secondtrimester serum microRNAs as potential biomarker for nondiabetic macrosomia. BioMed Research

International. 2014;**2014**:394125. DOI: 10.1155/2014/394125

[65] Ge Q, Zhu Y, Li H, Tian F, Xie X, Bai Y. Differential expression of circulating miRNAs in maternal plasma in pregnancies with fetal macrosomia. International Journal of Molecular Medicine. 2015;**35**:81-91. DOI: 10.3892/ ijmm.2014.1989

[66] Collares CV, Evangelista AF, Xavier DJ, Rassi DM, Arns T, Foss-Freitas MC, et al. Identifying common and specific microRNAs expressed in peripheral blood mononuclear cell of type 1, type 2, and gestational diabetes mellitus patients. BMC Research Notes. 2013;**6**:491. DOI: 10.1186/1756-0500-6-491

[67] Zhao C, Zhang T, Shi Z, Ding H, Ling X. MicroRNA-518d regulates PPARα protein expression in the placentas of females with gestational diabetes mellitus. Molecular Medicine Reports. 2014;**9**:2085-2090. DOI: 10.3892/mmr.2014.2058

[68] Abbott BD. Review of the expression of peroxisome proliferatoractivated receptors alpha (PPAR alpha), beta (PPAR beta), and gamma (PPAR gamma) in rodent and human development. Reproductive Toxicology. 2009;**27**:246-257. DOI: 10.1016/j. reprotox.2008.10.001

[69] Pawlak M, Lefebvre P, Staels B. Molecular mechanism of PPARα action and its impact on lipid metabolism, inflammation and fibrosis in non-alcoholic fatty liver disease. Journal of Hepatology. 2015;**62**:720-733. DOI: 10.1016/j.jhep.2014.10.039

[70] Li J, Song L, Zhou L, Wu J, Sheng C, Chen H, et al. A microRNA signature in gestational diabetes mellitus associated with risk of macrosomia. Cellular Physiology and Biochemistry. 2015;**37**:243-252. DOI: 10.1159/000430349

[71] Cao J-L, Zhang L, Li J, Tian S, Lv X-D, Wang X-Q, et al. Up-regulation of miR-98 and unraveling regulatory mechanisms in gestational diabetes mellitus. Scientific Reports. 2016;**6**:32268. DOI: 10.1038/srep32268

[72] Xu K, Bian D, Hao L, Huang F, Xu M, Qin J, et al. MicroRNA-503 contribute to pancreatic beta cell dysfunction by targeting the mTOR pathway in gestational diabetes mellitus. EXCLI Journal. 2017;**16**:1177-1187. DOI: 10.17179/excli2017-738

[73] Muralimanoharan S, Maloyan A, Myatt L. Mitochondrial function and glucose metabolism in the placenta with gestational diabetes mellitus: Role of miR-143. Clinical Science. 2016;**130**:931- 941. DOI: 10.1042/CS20160076

[74] Zhao C, Dong J, Jiang T, Shi Z, Yu B, Zhu Y, et al. Early second-trimester serum miRNA profiling predicts gestational diabetes mellitus. PLoS One. 2011;**6**:e23925. DOI: 10.1371/journal. pone.0023925

[75] Pheiffer C, Dias S, Rheeder P, Adam S. Decreased expression of circulating miR-20a-5p in south African women with gestational diabetes mellitus. Molecular Diagnosis & Therapy. 2018;**22**:345-352. DOI: 10.1007/ s40291-018-0325-0

[76] Tagoma A, Alnek K, Kirss A, Uibo R, Haller-Kikkatalo K. MicroRNA profiling of second trimester maternal plasma shows upregulation of miR-195-5p in patients with gestational diabetes. Gene. 2018;**672**:137-142. DOI: 10.1016/j.gene.2018.06.004

[77] Wander PL, Boyko EJ, Hevner K, Parikh VJ, Tadesse MG, Sorensen TK, et al. Circulating early- and midpregnancy microRNAs and risk of gestational diabetes. Diabetes Research and Clinical Practice. 2017;**132**:1-9. DOI: 10.1016/j.diabres.2017.07.024

[78] Zhu Y, Tian F, Li H, Zhou Y, Lu J, Ge Q. Profiling maternal plasma microRNA expression in early pregnancy to predict gestational diabetes mellitus. International Journal of Gynaecology and Obstetrics. 2015;**130**:49-53. DOI: 10.1016/j.ijgo.2015.01.010

[79] Cao Y-L, Jia Y-J, Xing B-H, Shi D-D, Dong X-J. Plasma microRNA-16-5p, -17-5p and -20a-5p: Novel diagnostic biomarkers for gestational diabetes mellitus. The Journal of Obstetrics and Gynaecology Research. 2017;**43**:974- 981. DOI: 10.1111/jog.13317

[80] Floris I, Descamps B, Vardeu A, Mitić T, Posadino AM, Shantikumar S, et al. Gestational diabetes mellitus impairs fetal endothelial cell functions through a mechanism involving microRNA-101 and histone methyltransferase enhancer of zester homolog-2. Arteriosclerosis, Thrombosis, and Vascular Biology. 2015;**35**:664-674. DOI: 10.1161/ ATVBAHA.114.304730

[81] Peng H-Y, Li H-P, Li M-Q. High glucose induces dysfunction of human umbilical vein endothelial cells by upregulating miR-137 in gestational diabetes mellitus. Microvascular Research. 2018;**118**:90-100. DOI: 10.1016/j.mvr.2018.03.002

[82] Tryggestad JB, Vishwanath A, Jiang S, Mallappa A, Teague AM, Takahashi Y, et al. Influence of gestational diabetes mellitus on human umbilical vein endothelial cell miRNA. Clinical Science. 2016;**130**:1955-1967. DOI: 10.1042/CS20160305

[83] Rodil-Garcia P, Arellanes-Licea EDC, Montoya-Contreras A, Salazar-Olivo LA. Analysis of microRNA expression in newborns with differential birth weight using newborn screening cards. International Journal of Molecular Sciences. 2017;**18**(12):pii:E2552. DOI: 10.3390/ijms18122552

**101**

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs*

RNA Biology. 2011;**8**:692-701. DOI:

[91] Gulyaeva LF, Kushlinskiy NE. Regulatory mechanisms of microRNA expression. Journal of Translational Medicine. 2016;**14**:143. DOI: 10.1186/s12967-016-0893-x

10.4161/rna.8.4.16029

*DOI: http://dx.doi.org/10.5772/intechopen.82102*

[85] Leidinger P, Backes C, Dahmke IN, Galata V, Huwer H, Stehle I, et al. What makes a blood cell based miRNA expression pattern disease specific?–A miRNome analysis of blood cell subsets in lung cancer patients and healthy controls. Oncotarget. 2014;**5**:9484-9497. DOI: 10.18632/

[87] Wang K, Yuan Y, Cho J-H, McClarty S, Baxter D, Galas DJ. Comparing the microRNA spectrum between serum and plasma. PLoS One. 2012;**7**:e41561. DOI: 10.1371/journal.pone.0041561

[88] Vigneron N, Meryet-Figuière M, Guttin A, Issartel J-P, Lambert B, Briand M, et al. Towards a new standardized method for circulating miRNAs profiling in clinical studies: Interest of the exogenous normalisation to improve miRNA signature accuracy. Molecular Oncology. 2016;**10**:981-992. DOI: 10.1016/j.molonc.2016.03.005

[89] Schwarzenbach H, da Silva AM, Calin G, Pantel K. Which is the accurate data normalisation strategy for microRNA quantification? Clinical Chemistry. 2015;**61**:1333-1342. DOI: 10.1373/clinchem.2015.239459

[90] Huang RS, Gamazon ER, Ziliak D, Wen Y, Im HK, Zhang W, et al. Population differences in microRNA expression and biological implications.

oncotarget.2419

[86] Leidinger P, Backes C, Meder B, Meese E, Keller A. The human miRNA repertoire of different blood compounds. BMC Genomics. 2014;**15**:474. DOI: 10.1186/1471-2164-15-474

[84] Kroh EM, Parkin RK, Mitchell PS, Tewari M. Analysis of circulating microRNA biomarkers in plasma and serum using quantitative reverse transcription-PCR (qRT-PCR). Methods. 2010;**50**:298-301. DOI: 10.1016/j.ymeth.2010.01.032

*Screening for Gestational Diabetes Mellitus: The Potential of MicroRNAs DOI: http://dx.doi.org/10.5772/intechopen.82102*

[84] Kroh EM, Parkin RK, Mitchell PS, Tewari M. Analysis of circulating microRNA biomarkers in plasma and serum using quantitative reverse transcription-PCR (qRT-PCR). Methods. 2010;**50**:298-301. DOI: 10.1016/j.ymeth.2010.01.032

*Gestational Diabetes Mellitus - An Overview with Some Recent Advances*

[78] Zhu Y, Tian F, Li H, Zhou Y, Lu J, Ge Q. Profiling maternal plasma microRNA

[79] Cao Y-L, Jia Y-J, Xing B-H, Shi D-D, Dong X-J. Plasma microRNA-16-5p, -17-5p and -20a-5p: Novel diagnostic biomarkers for gestational diabetes mellitus. The Journal of Obstetrics and Gynaecology Research. 2017;**43**:974-

expression in early pregnancy to predict gestational diabetes mellitus. International Journal of Gynaecology and Obstetrics. 2015;**130**:49-53. DOI:

10.1016/j.ijgo.2015.01.010

981. DOI: 10.1111/jog.13317

S, et al. Gestational diabetes mellitus impairs fetal endothelial cell functions through a mechanism involving microRNA-101 and histone methyltransferase enhancer of zester homolog-2. Arteriosclerosis, Thrombosis, and Vascular Biology. 2015;**35**:664-674. DOI: 10.1161/

ATVBAHA.114.304730

10.1042/CS20160305

10.3390/ijms18122552

[80] Floris I, Descamps B, Vardeu A, Mitić T, Posadino AM, Shantikumar

[81] Peng H-Y, Li H-P, Li M-Q. High glucose induces dysfunction of human umbilical vein endothelial cells by upregulating miR-137 in gestational diabetes mellitus. Microvascular Research. 2018;**118**:90-100. DOI: 10.1016/j.mvr.2018.03.002

[82] Tryggestad JB, Vishwanath A, Jiang S, Mallappa A, Teague AM, Takahashi Y, et al. Influence of gestational diabetes mellitus on human umbilical vein endothelial cell miRNA. Clinical Science. 2016;**130**:1955-1967. DOI:

[83] Rodil-Garcia P, Arellanes-Licea EDC, Montoya-Contreras A, Salazar-Olivo LA. Analysis of microRNA

expression in newborns with differential birth weight using newborn screening cards. International Journal of Molecular Sciences. 2017;**18**(12):pii:E2552. DOI:

[71] Cao J-L, Zhang L, Li J, Tian S, Lv X-D, Wang X-Q, et al. Up-regulation of miR-98 and unraveling regulatory mechanisms in gestational diabetes

2016;**6**:32268. DOI: 10.1038/srep32268

[72] Xu K, Bian D, Hao L, Huang F, Xu M, Qin J, et al. MicroRNA-503 contribute to pancreatic beta cell dysfunction by targeting the mTOR pathway in gestational diabetes mellitus. EXCLI Journal. 2017;**16**:1177-1187. DOI:

[73] Muralimanoharan S, Maloyan A, Myatt L. Mitochondrial function and glucose metabolism in the placenta with gestational diabetes mellitus: Role of miR-143. Clinical Science. 2016;**130**:931-

[74] Zhao C, Dong J, Jiang T, Shi Z, Yu B, Zhu Y, et al. Early second-trimester serum miRNA profiling predicts

gestational diabetes mellitus. PLoS One. 2011;**6**:e23925. DOI: 10.1371/journal.

[75] Pheiffer C, Dias S, Rheeder P, Adam S. Decreased expression of circulating miR-20a-5p in south African women with gestational diabetes mellitus. Molecular Diagnosis & Therapy. 2018;**22**:345-352. DOI: 10.1007/

[76] Tagoma A, Alnek K, Kirss A, Uibo R, Haller-Kikkatalo K. MicroRNA profiling of second trimester maternal plasma shows upregulation of miR-195-5p in patients with gestational diabetes. Gene. 2018;**672**:137-142. DOI:

941. DOI: 10.1042/CS20160076

mellitus. Scientific Reports.

10.17179/excli2017-738

pone.0023925

s40291-018-0325-0

10.1016/j.gene.2018.06.004

10.1016/j.diabres.2017.07.024

[77] Wander PL, Boyko EJ, Hevner K, Parikh VJ, Tadesse MG, Sorensen TK, et al. Circulating early- and midpregnancy microRNAs and risk of gestational diabetes. Diabetes Research and Clinical Practice. 2017;**132**:1-9. DOI:

**100**

[85] Leidinger P, Backes C, Dahmke IN, Galata V, Huwer H, Stehle I, et al. What makes a blood cell based miRNA expression pattern disease specific?–A miRNome analysis of blood cell subsets in lung cancer patients and healthy controls. Oncotarget. 2014;**5**:9484-9497. DOI: 10.18632/ oncotarget.2419

[86] Leidinger P, Backes C, Meder B, Meese E, Keller A. The human miRNA repertoire of different blood compounds. BMC Genomics. 2014;**15**:474. DOI: 10.1186/1471-2164-15-474

[87] Wang K, Yuan Y, Cho J-H, McClarty S, Baxter D, Galas DJ. Comparing the microRNA spectrum between serum and plasma. PLoS One. 2012;**7**:e41561. DOI: 10.1371/journal.pone.0041561

[88] Vigneron N, Meryet-Figuière M, Guttin A, Issartel J-P, Lambert B, Briand M, et al. Towards a new standardized method for circulating miRNAs profiling in clinical studies: Interest of the exogenous normalisation to improve miRNA signature accuracy. Molecular Oncology. 2016;**10**:981-992. DOI: 10.1016/j.molonc.2016.03.005

[89] Schwarzenbach H, da Silva AM, Calin G, Pantel K. Which is the accurate data normalisation strategy for microRNA quantification? Clinical Chemistry. 2015;**61**:1333-1342. DOI: 10.1373/clinchem.2015.239459

[90] Huang RS, Gamazon ER, Ziliak D, Wen Y, Im HK, Zhang W, et al. Population differences in microRNA expression and biological implications. RNA Biology. 2011;**8**:692-701. DOI: 10.4161/rna.8.4.16029

[91] Gulyaeva LF, Kushlinskiy NE. Regulatory mechanisms of microRNA expression. Journal of Translational Medicine. 2016;**14**:143. DOI: 10.1186/s12967-016-0893-x

Chapter 7

Abstract

and pregnancy.

1. Introduction

103

Mellitus

Leptin and Gestational Diabetes

Pilar Guadix, Antonio Pérez-Pérez,Teresa Vilariño-García,

Emerging research has highlighted the importance of leptin in fetal growth and

development, independent of its essential role in the regulation of feeding and energy metabolism. Leptin is now considered an important signaling molecule of the reproductive system, since it regulates the production of gonadotropins, the blastocyst formation and implantation, the normal placentation, as well as the fetoplacental communication. Placental leptin is an important cytokine which regulates placental functions in an autocrine or paracrine manner. Leptin seems to play a crucial role during the first stages of pregnancy as it modulates critical processes like proliferation, protein synthesis, invasion, and apoptosis in placental cells. Furthermore, deregulation of leptin levels has been correlated with the pathogenesis of various disorders associated with reproduction and gestation, including gestational diabetes mellitus (GDM). Due to the relevant incidence of the GDM and the importance of leptin, we decided to review the latest information available about leptin action in normal and GDM pregnancies to support the idea of leptin as an important factor and/or predictor of diverse disorders associated with reproduction

José L. Dueñas, Julieta Maymó, Cecilia Varone

Keywords: leptin, reproduction, placenta, GDM, microRNAs

Adipose tissue acts as an endocrine organ, secreting different molecules or adipokines. A link between body weight, adipokines, and success of pregnancy has been proposed, although it is not fully understood [1]. Leptin was the first adipokine claimed to be the "missing link" between fat and reproduction [2]. Leptin is considered as a pleiotropic hormone that regulates not only body weight but also many other functions, including the normal physiology of the reproductive system [3]. Importantly, this hormone is also produced by other tissues, especially placenta [4].

Placental formation during human gestation is crucial for embryonic progress and successful pregnancy outcome, allowing metabolic exchange and producing steroids, hormones, growth factors, and cytokines that are critical for the maintenance of pregnancy [5, 6]. Trophoblast cells play an essential role in the development of placenta. These cells differentiate in two distinct types: extravillous and villous trophoblast. In the extravillous pathway, cytotrophoblasts proliferate,

and Víctor Sánchez-Margalet

#### Chapter 7

## Leptin and Gestational Diabetes Mellitus

Pilar Guadix, Antonio Pérez-Pérez,Teresa Vilariño-García, José L. Dueñas, Julieta Maymó, Cecilia Varone and Víctor Sánchez-Margalet

#### Abstract

Emerging research has highlighted the importance of leptin in fetal growth and development, independent of its essential role in the regulation of feeding and energy metabolism. Leptin is now considered an important signaling molecule of the reproductive system, since it regulates the production of gonadotropins, the blastocyst formation and implantation, the normal placentation, as well as the fetoplacental communication. Placental leptin is an important cytokine which regulates placental functions in an autocrine or paracrine manner. Leptin seems to play a crucial role during the first stages of pregnancy as it modulates critical processes like proliferation, protein synthesis, invasion, and apoptosis in placental cells. Furthermore, deregulation of leptin levels has been correlated with the pathogenesis of various disorders associated with reproduction and gestation, including gestational diabetes mellitus (GDM). Due to the relevant incidence of the GDM and the importance of leptin, we decided to review the latest information available about leptin action in normal and GDM pregnancies to support the idea of leptin as an important factor and/or predictor of diverse disorders associated with reproduction and pregnancy.

Keywords: leptin, reproduction, placenta, GDM, microRNAs

#### 1. Introduction

Adipose tissue acts as an endocrine organ, secreting different molecules or adipokines. A link between body weight, adipokines, and success of pregnancy has been proposed, although it is not fully understood [1]. Leptin was the first adipokine claimed to be the "missing link" between fat and reproduction [2]. Leptin is considered as a pleiotropic hormone that regulates not only body weight but also many other functions, including the normal physiology of the reproductive system [3]. Importantly, this hormone is also produced by other tissues, especially placenta [4].

Placental formation during human gestation is crucial for embryonic progress and successful pregnancy outcome, allowing metabolic exchange and producing steroids, hormones, growth factors, and cytokines that are critical for the maintenance of pregnancy [5, 6]. Trophoblast cells play an essential role in the development of placenta. These cells differentiate in two distinct types: extravillous and villous trophoblast. In the extravillous pathway, cytotrophoblasts proliferate,

differentiate into an invasive phenotype, and penetrate in the maternal decidua and myometrium. Meanwhile, in the villous pathway, mononuclear cytotrophoblasts fuse to form a specialized multinuclear syncytium called syncytiotrophoblast [7]. In normal pregnancy, trophoblast invasion is a critical step in remodeling the maternal spiral arteries to adequately perfuse the developing placenta and fetus [8]. In this sense, deregulation of leptin levels has been implicated in the pathogenesis of gestational diabetes mellitus (GDM) [9].

prerequisite of a high-capacity transport interface. In 1997, leptin was described as a new placental hormone in humans [14]. In fact, during pregnancy, circulating leptin levels are also increased due to leptin production by trophoblastic cells [30].

To alter intracellular signaling and function, leptin must bind to the receptor (LEPR) [32]. There are six different isoforms of LEPR (a–f) that are produced by alternative RNA splicing [33]. The only isoform that has a transmembrane domain that is capable of activating signal transduction pathways is LEPRb, whereas the other five short LEPR isoforms have either a truncated or no transmembrane domain and are unable to activate signaling pathways [33]. Activation of LEPRb results in an upregulation of a number of signal transduction pathways, including the Janus kinase/signal transducers and activators of the transcription pathway (JAK/STAT), as well as the mitogen-activated protein kinase (MAPK) and

phosphatidylinositol 3-kinase (PI3K) pathways [34]. Research findings do indicate that there may be fetal-to-maternal leptin exchange across the placenta [35]. However, to date, it is not known which receptor is mediating this transportation.

and immunomodulation [13]. Leptin is now considered an important regulator during the first stages of pregnancy, modulating proliferation, invasion, apoptosis,

Leptin has physiological effects on the placenta, including angiogenesis, growth,

The control of cell proliferation is critical for a correct placental development, and it is finely regulated [42]. Altered rates of cytotrophoblast proliferation are associated with different pathologies; levels are enhanced with increased fetal growth (macrosomia) and diminished in fetal growth restriction [42]. Others factors in maternal circulation might coordinately stimulate proliferation, differentiation, and survival [43, 44] through the activation of multiple kinases [43–45] and

During placentation, cytotrophoblasts and syncytiotrophoblast keep a subset of cells in direct contact to the villous basement membranes. In the extravillous compartment, cell proliferation favors the invasion of the uterine stroma. Similarly, in the villous compartment, cells undergo syncytial fusion directed by specific tran-

The role of MAPK in regulating trophoblast turnover is well documented in both human and animal systems [43, 44, 47]. Moreover, it was shown that leptin induces proliferative activity in many human cell types [48–50], mainly via MAPK activation [51]. We have demonstrated that leptin promotes proliferation of trophoblast cells by this MAPK pathway [41, 52]. We have also found that leptin dose-dependently stimulates protein synthesis by the activation of translation machinery [36, 53]. In this context, it is interesting to mention the role of Sam68, an RNA-binding protein originally identified as the substrate of Src during mitosis and a member of the signal transduction and activation of RNA metabolism (STAR) family [54, 55]. Leptin stimulates Tyr-phosphorylation of Sam68 in the trophoblast, mediating the dissociation from RNA, suggesting that leptin signaling could modulate RNA metabolism [48, 56]. Recent data indicate that microRNAs have a fundamental role in a variety of physiological and pathological processes. In this context, studies of microRNA expression have revealed that some microRNAs are abundantly expressed in the placenta [57]. However, the signature of miRNAs in the placenta

In placental villi, cell turnover is tightly regulated, via apoptotic cascade [49]. In normal pregnancy, apoptosis is an essential feature of placental development, and it is well stablished that trophoblast apoptosis increases with placental growth and advancing gestation [50]. Leptin prevents early and late events of apoptosis via MAPK pathway [41, 52]. The role of leptin was also studied under different stress

After delivery, leptin levels return to normal levels [31].

Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

and protein synthesis, in placenta [36–41].

phosphatases [45].

scription factors [46].

has yet to be elucidated.

105

#### 2. Leptin and reproduction

Reproductive function depends on the energy reserves stored in the adipose tissue. The large energy needs for a hypothetical pregnancy was the original rationale to explain the disruption of reproductive function by low fat reserves. This led to the hypothesis of an endocrine signal that conveys information to the brain about the size of fat stores [10]. Thus, leptin was the first adipokine claimed to be the "missing link" between fat and reproduction [2]. Leptin modulates satiety and energy homeostasis [11, 12] but is also produced by the placenta. Thus, it was suggested that the effects of placental leptin on the mother may contribute to endocrine-mediated alterations in energy balance, such as the mobilization of maternal fat, which occurs during the second half of pregnancy [13, 14]. In addition, leptin has been found to influence several reproductive functions, including embryo development and implantation [15]. Moreover, animal models have demonstrated that leptin-deficient mice are subfertile and fertility can be restored by exogenous leptin [16]. This adipokine may therefore play a critical role in regulating both energy homeostasis and the reproductive system [17].

Leptin increments the secretion of gonadotropin hormones, by acting centrally at the hypothalamus [18]. In addition, because leptin has been shown to be influenced by steroid hormones and can stimulate LH release, leptin may act as a permissive factor in the development of puberty [19].

Leptin can also regulate ovary functions [20–23]. Thus, leptin resistance and hyperleptinemia in obesity lead to altered follicle function, whereas in conditions in which nutritional status is suboptimal, leptin deficiency results in hypothalamicpituitary gonadal axis dysfunction [24, 25].

In addition, a significant role of leptin in embryo implantation was proposed. Leptin receptor (LEPR) is specifically expressed at the blastocyst stage [26], and it was also reported that leptin is present in conditioned media from human blastocysts, promoting embryo development, suggesting a function in the blastocystendometrial dialog [27].

#### 3. Leptin and placenta

The implantation involves complex and synchronized molecular and cellular events between the implanting embryo and uterus, and these events are regulated by autocrine and paracrine factors [5]. Fetal growth depends on the ability of the placenta to supply nutrients adequate to meet fetal demand, which increases as gestation progresses. Villous cytotrophoblast is a progenitor cell population that produces daughter cells to support the expansion of the syncytium as placental surface area increases as well as the expansion of cytotrophoblast columns, which contain the cells destined to invade maternal decidua [28]. The placenta grows exponentially in the first and early second trimester, but growth has slowed down by term [29]. Therefore, placental growth, especially in early gestation, is a

#### Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

differentiate into an invasive phenotype, and penetrate in the maternal decidua and myometrium. Meanwhile, in the villous pathway, mononuclear cytotrophoblasts fuse to form a specialized multinuclear syncytium called syncytiotrophoblast [7]. In normal pregnancy, trophoblast invasion is a critical step in remodeling the maternal spiral arteries to adequately perfuse the developing placenta and fetus [8]. In this sense, deregulation of leptin levels has been implicated in the pathogenesis of

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

Reproductive function depends on the energy reserves stored in the adipose tissue. The large energy needs for a hypothetical pregnancy was the original rationale to explain the disruption of reproductive function by low fat reserves. This led to the hypothesis of an endocrine signal that conveys information to the brain about the size of fat stores [10]. Thus, leptin was the first adipokine claimed to be the "missing link" between fat and reproduction [2]. Leptin modulates satiety and energy homeostasis [11, 12] but is also produced by the placenta. Thus, it was suggested that the effects of placental leptin on the mother may contribute to endocrine-mediated alterations in energy balance, such as the mobilization of maternal fat, which occurs during the second half of pregnancy [13, 14]. In addition, leptin has been found to influence several reproductive functions, including embryo development and implantation [15]. Moreover, animal models have demonstrated that leptin-deficient mice are subfertile and fertility can be restored by exogenous leptin [16]. This adipokine may therefore play a critical role in regulating

Leptin increments the secretion of gonadotropin hormones, by acting centrally

Leptin can also regulate ovary functions [20–23]. Thus, leptin resistance and hyperleptinemia in obesity lead to altered follicle function, whereas in conditions in which nutritional status is suboptimal, leptin deficiency results in hypothalamic-

In addition, a significant role of leptin in embryo implantation was proposed. Leptin receptor (LEPR) is specifically expressed at the blastocyst stage [26], and it was also reported that leptin is present in conditioned media from human blastocysts, promoting embryo development, suggesting a function in the blastocyst-

The implantation involves complex and synchronized molecular and cellular events between the implanting embryo and uterus, and these events are regulated by autocrine and paracrine factors [5]. Fetal growth depends on the ability of the placenta to supply nutrients adequate to meet fetal demand, which increases as gestation progresses. Villous cytotrophoblast is a progenitor cell population that produces daughter cells to support the expansion of the syncytium as placental surface area increases as well as the expansion of cytotrophoblast columns, which contain the cells destined to invade maternal decidua [28]. The placenta grows exponentially in the first and early second trimester, but growth has slowed down by term [29]. Therefore, placental growth, especially in early gestation, is a

at the hypothalamus [18]. In addition, because leptin has been shown to be influenced by steroid hormones and can stimulate LH release, leptin may act as a

both energy homeostasis and the reproductive system [17].

permissive factor in the development of puberty [19].

pituitary gonadal axis dysfunction [24, 25].

endometrial dialog [27].

3. Leptin and placenta

104

gestational diabetes mellitus (GDM) [9].

2. Leptin and reproduction

prerequisite of a high-capacity transport interface. In 1997, leptin was described as a new placental hormone in humans [14]. In fact, during pregnancy, circulating leptin levels are also increased due to leptin production by trophoblastic cells [30]. After delivery, leptin levels return to normal levels [31].

To alter intracellular signaling and function, leptin must bind to the receptor (LEPR) [32]. There are six different isoforms of LEPR (a–f) that are produced by alternative RNA splicing [33]. The only isoform that has a transmembrane domain that is capable of activating signal transduction pathways is LEPRb, whereas the other five short LEPR isoforms have either a truncated or no transmembrane domain and are unable to activate signaling pathways [33]. Activation of LEPRb results in an upregulation of a number of signal transduction pathways, including the Janus kinase/signal transducers and activators of the transcription pathway (JAK/STAT), as well as the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways [34]. Research findings do indicate that there may be fetal-to-maternal leptin exchange across the placenta [35]. However, to date, it is not known which receptor is mediating this transportation.

Leptin has physiological effects on the placenta, including angiogenesis, growth, and immunomodulation [13]. Leptin is now considered an important regulator during the first stages of pregnancy, modulating proliferation, invasion, apoptosis, and protein synthesis, in placenta [36–41].

The control of cell proliferation is critical for a correct placental development, and it is finely regulated [42]. Altered rates of cytotrophoblast proliferation are associated with different pathologies; levels are enhanced with increased fetal growth (macrosomia) and diminished in fetal growth restriction [42]. Others factors in maternal circulation might coordinately stimulate proliferation, differentiation, and survival [43, 44] through the activation of multiple kinases [43–45] and phosphatases [45].

During placentation, cytotrophoblasts and syncytiotrophoblast keep a subset of cells in direct contact to the villous basement membranes. In the extravillous compartment, cell proliferation favors the invasion of the uterine stroma. Similarly, in the villous compartment, cells undergo syncytial fusion directed by specific transcription factors [46].

The role of MAPK in regulating trophoblast turnover is well documented in both human and animal systems [43, 44, 47]. Moreover, it was shown that leptin induces proliferative activity in many human cell types [48–50], mainly via MAPK activation [51]. We have demonstrated that leptin promotes proliferation of trophoblast cells by this MAPK pathway [41, 52]. We have also found that leptin dose-dependently stimulates protein synthesis by the activation of translation machinery [36, 53].

In this context, it is interesting to mention the role of Sam68, an RNA-binding protein originally identified as the substrate of Src during mitosis and a member of the signal transduction and activation of RNA metabolism (STAR) family [54, 55]. Leptin stimulates Tyr-phosphorylation of Sam68 in the trophoblast, mediating the dissociation from RNA, suggesting that leptin signaling could modulate RNA metabolism [48, 56]. Recent data indicate that microRNAs have a fundamental role in a variety of physiological and pathological processes. In this context, studies of microRNA expression have revealed that some microRNAs are abundantly expressed in the placenta [57]. However, the signature of miRNAs in the placenta has yet to be elucidated.

In placental villi, cell turnover is tightly regulated, via apoptotic cascade [49]. In normal pregnancy, apoptosis is an essential feature of placental development, and it is well stablished that trophoblast apoptosis increases with placental growth and advancing gestation [50]. Leptin prevents early and late events of apoptosis via MAPK pathway [41, 52]. The role of leptin was also studied under different stress

conditions like serum deprivation, hyperthermia, and acidic stress [39, 40]. Under serum deprivation, leptin increased the anti-apoptotic BCL-2 protein expression, while it downregulated the pro-apoptotic BAX and BID proteins expression as well as caspase-3 active form and cleaved PARP-1 fragment in Swan-71 cells and placental explants. In addition, it was demonstrated that p53 and its phosphorylation in Ser-46 are downregulated by leptin suggesting that leptin plays a pivotal role for apoptotic signaling by p53 [37]. Recent studies have demonstrated that MAPK and PI3K pathways are necessary for this anti-apoptotic leptin action, and it was also demonstrated that MDM-2 expression is regulated by leptin [38]. In placental explants cultured at high temperatures (40 and 42°C) and a pH acid (<7.3), the expression of Ser-46 p53, p53AIP1, p21, and caspase-3 is increased, and, these effects are significantly attenuated by leptin, indicating that leptin is a pro-survival placental cytokine [39, 40].

affects 3–8% of all pregnancies [72, 73]. The prevalence of GDM has increased in recent decades due to increased average age of pregnant females and increased risk of obesity [74]. However, GDM is associated with numerous complications including macrosomia, neonatal metabolic disorders, respiratory distress syndrome, and neonatal death as well as a predisposition for the development of metabolic syn-

The placenta is thought to have a critical role in the pathogenesis of gestational diabetes mellitus, as GDM-associated complications resolve following delivery. Therefore, aberrant development and functions of the placenta, including placental overgrowth, have been implicated as important factors that contribute to GDMassociated complications [77, 78]. GDM is associated with insulin resistance, hyperinsulinemia, and hyperleptinemia, and these GDM-associated conditions dis-

It has been found that leptin and LEPR expressions are increased in placenta from GDM [9, 70], and, in fact leptin was proposed as a first-trimester biochemical predictor of GDM [81, 82]. In addition it was suggested that hyperinsulinemia may regulate placental leptin production acting as a circulating signal to control fetal homeostasis [73, 83]. Furthermore, it is thought that maternal glucose regulates cord blood leptin levels, and this could explain why newborns exposed to GDM have an increased risk of obesity [84]. Comparison of the placental gene expression profile between normal and diabetic pregnancies indicates that increased leptin synthesis in GDM is correlated with higher production of pro-inflammatory cytokines such as IL-6 and TNFα, causing a chronic inflammatory environment that

Our group has reported that insulin induces leptin expression in trophoblastic cells by increasing leptin promoter activity [86]. It is known that leptin and insulin share several signaling pathways, such as JAK2/STAT-3, MAPK, and PI3K. Moreover, we could demonstrate that in GDM, the basal phosphorylation of STAT-3, MAPK 1/3, and Akt is increased in the placenta, with resistance to a further stimulation with leptin or insulin in vitro, suggesting synergistic interaction between

turb placental nutrient transport and fetal nutrient supply [79, 80].

insulin and leptin signaling and action in human placenta [9].

On the other hand, GDM is associated with increased incidence of polyhydramnios, due to an increase in amniotic fluid volume, suggesting that aquaporins (AQP), such as AQP9 expression, could be altered in GDM [87, 88]. Besides, when maternal circulating glucose levels are controlled, they have normal amniotic fluid volume. AQP9 is also a transporter for glycerol and may also provide this substrate to the fetus. In this context, we have found that AQP9 mRNA and protein expressions are overexpressed in placentas from women with GDM. These data could suggest that during GDM the overexpression of AQP9, which correlates with higher leptin plasma levels, increments glycerol transport to the fetus which may help to cover the increase in energy needs that may occur during this gesta-

Nevertheless, even though any nutritional or lifestyle intervention aimed to reduce weight produce a decrease in leptin levels, both in gestational diabetes and in general population, no therapeutic intervention, using leptin as a pharmacological

Gene expression can be regulated by short (18–22-nucleotide) noncoding RNAs,

microRNAs, derived from long primary transcripts (pre-microRNAs) through sequential processing by two enzymes, Drosha and Dicer, and then incorporated

target, has so far been used in the management of gestational diabetes.

dromes and typ. 2 diabetes [75, 76].

Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

enhances leptin production [85].

tional metabolic disorder [89].

6. Leptin and microRNAs

107

#### 4. Leptin and immune system in placenta

One of the most important placental functions is to prevent embryo rejection by the maternal immune system to enable its correct development [51]. To ensure normal pregnancy, trophoblast differentiation requires potent immunomodulatory mechanisms to prevent rejection of syncytiotrophoblast and invasive trophoblast by alloreactive lymphocytes and natural killer (NK) cells present in maternal blood and decidua [58]. Inflammatory mediators such as IL-6, IL-1β, TNFα, and prostaglandins are produced and secreted by the human placenta, and these cytokines play an important role in a number of normal and abnormal inflammatory processes, including the initiation and progression of human labor [59–61]. There are several homologies between the expression and regulation of cytokines and inflammationrelated genes in the placenta and in the white adipose tissue. In this regard, leptin effects include the promotion of inflammation and the modulation of adaptive and innate immunity [56, 62, 63]. Thus, placental leptin acts as an immune modulator, regulating the generation of matrix metalloproteinases, arachidonic acid products, nitric oxide production, and T cell cytokines [61]. Interestingly, leptin expression is also regulated by IL-6, IL-1α, IL-1β, and IFN-ϒ [31, 64, 65].

It was reported that leptin stimulates IL-6 secretion in human trophoblast cells [66, 67]. In addition, TNFα release from human placenta is also stimulated by leptin, and it was demonstrated that NF-ҡB and PPAR-γ are important mediators of this effect [68]. Recently, we have found that leptin induces HLA-G expression in placenta. HLA-G has potent immunosuppressive effects promoting apoptosis of activated CD8+ T lymphocytes, the generation of tolerogenic antigen-presenting cells, and the prevention of NK cell-mediated cytotoxicity. These data place leptin as a placental cytokine which confers to trophoblast cells a tolerogenic phenotype to prevent immunological damage during the first steps of pregnancy [69].

Pro-inflammatory leptin actions may also have significant implications in the pathogenesis of various disorders during pregnancy, such as GDM, which is characterized by increased leptin expression. In this sense, placental leptin may contribute to the incremented circulating levels of pro-inflammatory mediators that are evident in these pregnancy diseases, whereas successful pregnancy is associated with downregulation of intrauterine pro-inflammatory cytokines [9, 70, 71].

#### 5. Leptin and gestational diabetes mellitus

Gestational diabetes mellitus, characterized by glucose intolerance diagnosed during pregnancy, is one of the most common complications in pregnancy and

#### Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

conditions like serum deprivation, hyperthermia, and acidic stress [39, 40]. Under serum deprivation, leptin increased the anti-apoptotic BCL-2 protein expression, while it downregulated the pro-apoptotic BAX and BID proteins expression as well as caspase-3 active form and cleaved PARP-1 fragment in Swan-71 cells and placental explants. In addition, it was demonstrated that p53 and its phosphorylation in Ser-46 are downregulated by leptin suggesting that leptin plays a pivotal role for apoptotic signaling by p53 [37]. Recent studies have demonstrated that MAPK and PI3K pathways are necessary for this anti-apoptotic leptin action, and it was also demonstrated that MDM-2 expression is regulated by leptin [38]. In placental explants cultured at high temperatures (40 and 42°C) and a pH acid (<7.3), the expression of Ser-46 p53, p53AIP1, p21, and caspase-3 is increased, and, these effects are significantly attenuated by leptin, indicating that leptin is a pro-survival placental cytokine [39, 40].

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

One of the most important placental functions is to prevent embryo rejection by

It was reported that leptin stimulates IL-6 secretion in human trophoblast cells

Pro-inflammatory leptin actions may also have significant implications in the pathogenesis of various disorders during pregnancy, such as GDM, which is characterized by increased leptin expression. In this sense, placental leptin may contribute to the incremented circulating levels of pro-inflammatory mediators that are evident in these pregnancy diseases, whereas successful pregnancy is associated with downregulation of intrauterine pro-inflammatory cytokines [9, 70, 71].

Gestational diabetes mellitus, characterized by glucose intolerance diagnosed during pregnancy, is one of the most common complications in pregnancy and

[66, 67]. In addition, TNFα release from human placenta is also stimulated by leptin, and it was demonstrated that NF-ҡB and PPAR-γ are important mediators of this effect [68]. Recently, we have found that leptin induces HLA-G expression in placenta. HLA-G has potent immunosuppressive effects promoting apoptosis of activated CD8+ T lymphocytes, the generation of tolerogenic antigen-presenting cells, and the prevention of NK cell-mediated cytotoxicity. These data place leptin as a placental cytokine which confers to trophoblast cells a tolerogenic phenotype to

prevent immunological damage during the first steps of pregnancy [69].

the maternal immune system to enable its correct development [51]. To ensure normal pregnancy, trophoblast differentiation requires potent immunomodulatory mechanisms to prevent rejection of syncytiotrophoblast and invasive trophoblast by alloreactive lymphocytes and natural killer (NK) cells present in maternal blood and decidua [58]. Inflammatory mediators such as IL-6, IL-1β, TNFα, and prostaglandins are produced and secreted by the human placenta, and these cytokines play an important role in a number of normal and abnormal inflammatory processes, including the initiation and progression of human labor [59–61]. There are several homologies between the expression and regulation of cytokines and inflammationrelated genes in the placenta and in the white adipose tissue. In this regard, leptin effects include the promotion of inflammation and the modulation of adaptive and innate immunity [56, 62, 63]. Thus, placental leptin acts as an immune modulator, regulating the generation of matrix metalloproteinases, arachidonic acid products, nitric oxide production, and T cell cytokines [61]. Interestingly, leptin expression is

4. Leptin and immune system in placenta

also regulated by IL-6, IL-1α, IL-1β, and IFN-ϒ [31, 64, 65].

5. Leptin and gestational diabetes mellitus

106

affects 3–8% of all pregnancies [72, 73]. The prevalence of GDM has increased in recent decades due to increased average age of pregnant females and increased risk of obesity [74]. However, GDM is associated with numerous complications including macrosomia, neonatal metabolic disorders, respiratory distress syndrome, and neonatal death as well as a predisposition for the development of metabolic syndromes and typ. 2 diabetes [75, 76].

The placenta is thought to have a critical role in the pathogenesis of gestational diabetes mellitus, as GDM-associated complications resolve following delivery. Therefore, aberrant development and functions of the placenta, including placental overgrowth, have been implicated as important factors that contribute to GDMassociated complications [77, 78]. GDM is associated with insulin resistance, hyperinsulinemia, and hyperleptinemia, and these GDM-associated conditions disturb placental nutrient transport and fetal nutrient supply [79, 80].

It has been found that leptin and LEPR expressions are increased in placenta from GDM [9, 70], and, in fact leptin was proposed as a first-trimester biochemical predictor of GDM [81, 82]. In addition it was suggested that hyperinsulinemia may regulate placental leptin production acting as a circulating signal to control fetal homeostasis [73, 83]. Furthermore, it is thought that maternal glucose regulates cord blood leptin levels, and this could explain why newborns exposed to GDM have an increased risk of obesity [84]. Comparison of the placental gene expression profile between normal and diabetic pregnancies indicates that increased leptin synthesis in GDM is correlated with higher production of pro-inflammatory cytokines such as IL-6 and TNFα, causing a chronic inflammatory environment that enhances leptin production [85].

Our group has reported that insulin induces leptin expression in trophoblastic cells by increasing leptin promoter activity [86]. It is known that leptin and insulin share several signaling pathways, such as JAK2/STAT-3, MAPK, and PI3K. Moreover, we could demonstrate that in GDM, the basal phosphorylation of STAT-3, MAPK 1/3, and Akt is increased in the placenta, with resistance to a further stimulation with leptin or insulin in vitro, suggesting synergistic interaction between insulin and leptin signaling and action in human placenta [9].

On the other hand, GDM is associated with increased incidence of polyhydramnios, due to an increase in amniotic fluid volume, suggesting that aquaporins (AQP), such as AQP9 expression, could be altered in GDM [87, 88]. Besides, when maternal circulating glucose levels are controlled, they have normal amniotic fluid volume. AQP9 is also a transporter for glycerol and may also provide this substrate to the fetus. In this context, we have found that AQP9 mRNA and protein expressions are overexpressed in placentas from women with GDM. These data could suggest that during GDM the overexpression of AQP9, which correlates with higher leptin plasma levels, increments glycerol transport to the fetus which may help to cover the increase in energy needs that may occur during this gestational metabolic disorder [89].

Nevertheless, even though any nutritional or lifestyle intervention aimed to reduce weight produce a decrease in leptin levels, both in gestational diabetes and in general population, no therapeutic intervention, using leptin as a pharmacological target, has so far been used in the management of gestational diabetes.

#### 6. Leptin and microRNAs

Gene expression can be regulated by short (18–22-nucleotide) noncoding RNAs, microRNAs, derived from long primary transcripts (pre-microRNAs) through sequential processing by two enzymes, Drosha and Dicer, and then incorporated

into the RNA silencing complex, where they target homologous mRNAs. In mice, loss or inactivation of Dicer leads to multiple developmental defects [90, 91], and it has been demonstrated that in human placenta, cytotrophoblast proliferation is increased following Dicer [92]; however, the individual microRNAs responsible for these effects are unknown. In silico network analysis identified microRNAs (miR-145 and let-7a) that influence the expression of components of nodal signaling pathways. The large network is bridged by nodal molecules, such as mitogenactivated protein kinase (MAPK1/2), and AKT, which are recognized components of pro-mitogenic signaling pathways [20]. In fact, the role of MAPK1/2 in regulating trophoblast turnover is well documented in both human and animal systems [43, 44, 47]. In this context, we have reported an increased activation of MAPK 1/2 in response to leptin in trophoblastic cells from the human placenta. Thus, it is tempting to speculate that altered microRNAs expression influences the leptin expression and contributes to the pathogenesis of the GDM. However, the signature of microRNAs in the leptin expression in the placenta both in normal pregnancy and GDM remains to be elucidated. Therefore, it will be interesting to determine, in future studies, the combined role of these microRNAs in the leptin expression in normal placenta and in placenta from pregnancy pathology associated with altered placental growth (e.g., GDM) in order to clarify the regulation of placental growth by leptin.

cells. These actions are very important since cell proliferation and apoptotic cascades are critical for the correct placental development and function. Moreover, an important role of leptin in the regulation of immune mechanisms at the maternal

association of leptin with GDM and to stablish leptin as a biomarker for this pathology or the development of microRNA-based approaches to therapeutic targeting for correcting the abnormal placental growth and cell turnover seen in

Observational studies have demonstrated that states of leptin overabundance or resistance can be associated with GDM. Moreover, it is also established that obesity may lead to deregulation in leptin function that results in maternal disease and clinical studies demonstrate an impact of obesity with an increased risk of a number of diseases in adulthood, including metabolic disease. In this context, leptin deregulation has been implicated in the pathogenesis of GDM. It is well accepted that leptin and LEPR expressions are increased in placentas from GDM, which may be relevant to control fetal homeostasis. Moreover, a role for microRNAs in the regulation of placental growth has been suggested, and expression profiling in the studies has shown expression and gestational changes in microRNA levels that demand functional evaluation. Further investigation is needed to fully elucidate the

interface has been suggested.

Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

GDM.

Disclosure of interests

Author details

Julieta Maymó<sup>3</sup>

of Seville, Spain

†

109

The authors declare no conflict of interest.

\*Address all correspondence to: margalet@us.es

provided the original work is properly cited.

Pilar Guadix1†, Antonio Pérez-Pérez2†, Teresa Vilariño-García<sup>2</sup>

These authors contribute equally to this work as first authors

, Cecilia Varone<sup>3</sup> and Víctor Sánchez-Margalet<sup>2</sup>

1 Obstetrics and Gynecology Unit, Virgen Macarena University Hospital, University

2 Department of Medical Biochemistry and Molecular Biology, and Immunology,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Virgen Macarena University Hospital, University of Seville, Seville, Spain

3 Laboratory of Placental Molecular Physiology, Department of Biological Chemistry, School of Sciences, University of Buenos Aires, Argentina

, José L. Dueñas<sup>1</sup>

\*

,

#### 7. Leptin in fetal development

Obesity is associated with significantly elevated plasma leptin concentrations due to an increase in white adipose tissue compared with healthy individuals [93]. As obesity rates are increasing rapidly in the Western world, so is increasing the number of obese women who become pregnant. Importantly, obese pregnant women have significantly elevated plasma leptin concentrations compared with nonobese pregnant women throughout pregnancy [94]. Even though no differences in placental leptin production has been shown, there is a downregulation of LEPRb expression in the placenta of obese mothers, which would cause placental leptin resistance (in addition to the central leptin resistance that occurs during normal pregnancy) that may be attempting to modulate fetal growth under high-energy conditions [95, 96]. Despite the complications associated with pregnancies in obese women, the offspring may be growth restricted, normal weight, or macrosomic. However, after birth, babies born from obese mothers are exposed to elevated leptin concentrations in the maternal milk [97], which suggests that the postnatal environment may increase infant growth and development, increasing the risk of developing a number of diseases in adulthood. Therefore, alterations in maternalplacental-fetal leptin exchange may modify the development of the fetus and contribute to the increased risk of developing disease in adulthood.

#### 8. Conclusions

In conclusion, it could be affirmed that leptin controls reproduction depending on the energy state of the body and sufficient leptin levels are a prerequisite for the maintenance of reproductive capacity. The present review was focused in placental leptin effects during gestation, when leptin levels are increased due to leptin production by trophoblastic cells. Thus, leptin has a wide range of biological functions on trophoblast cells and a role in successful establishment of pregnancy. In this sense, leptin promotes proliferation, protein synthesis, and survival of placental

#### Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

into the RNA silencing complex, where they target homologous mRNAs. In mice, loss or inactivation of Dicer leads to multiple developmental defects [90, 91], and it has been demonstrated that in human placenta, cytotrophoblast proliferation is increased following Dicer [92]; however, the individual microRNAs responsible for these effects are unknown. In silico network analysis identified microRNAs (miR-145 and let-7a) that influence the expression of components of nodal signaling pathways. The large network is bridged by nodal molecules, such as mitogenactivated protein kinase (MAPK1/2), and AKT, which are recognized components of pro-mitogenic signaling pathways [20]. In fact, the role of MAPK1/2 in regulating trophoblast turnover is well documented in both human and animal systems [43, 44, 47]. In this context, we have reported an increased activation of MAPK 1/2 in response to leptin in trophoblastic cells from the human placenta. Thus, it is tempting to speculate that altered microRNAs expression influences the leptin expression and contributes to the pathogenesis of the GDM. However, the signature of microRNAs in the leptin expression in the placenta both in normal pregnancy and GDM remains to be elucidated. Therefore, it will be interesting to determine, in future studies, the combined role of these microRNAs in the leptin expression in normal placenta and in placenta from pregnancy pathology associated with altered placental growth (e.g., GDM) in order to clarify the regulation of placental growth

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

Obesity is associated with significantly elevated plasma leptin concentrations due to an increase in white adipose tissue compared with healthy individuals [93]. As obesity rates are increasing rapidly in the Western world, so is increasing the number of obese women who become pregnant. Importantly, obese pregnant women have significantly elevated plasma leptin concentrations compared with nonobese pregnant women throughout pregnancy [94]. Even though no differences in placental leptin production has been shown, there is a downregulation of LEPRb expression in the placenta of obese mothers, which would cause placental leptin resistance (in addition to the central leptin resistance that occurs during normal pregnancy) that may be attempting to modulate fetal growth under high-energy conditions [95, 96]. Despite the complications associated with pregnancies in obese women, the offspring may be growth restricted, normal weight, or macrosomic. However, after birth, babies born from obese mothers are exposed to elevated leptin concentrations in the maternal milk [97], which suggests that the postnatal environment may increase infant growth and development, increasing the risk of developing a number of diseases in adulthood. Therefore, alterations in maternalplacental-fetal leptin exchange may modify the development of the fetus and

contribute to the increased risk of developing disease in adulthood.

In conclusion, it could be affirmed that leptin controls reproduction depending on the energy state of the body and sufficient leptin levels are a prerequisite for the maintenance of reproductive capacity. The present review was focused in placental leptin effects during gestation, when leptin levels are increased due to leptin production by trophoblastic cells. Thus, leptin has a wide range of biological functions on trophoblast cells and a role in successful establishment of pregnancy. In this sense, leptin promotes proliferation, protein synthesis, and survival of placental

by leptin.

8. Conclusions

108

7. Leptin in fetal development

cells. These actions are very important since cell proliferation and apoptotic cascades are critical for the correct placental development and function. Moreover, an important role of leptin in the regulation of immune mechanisms at the maternal interface has been suggested.

Observational studies have demonstrated that states of leptin overabundance or resistance can be associated with GDM. Moreover, it is also established that obesity may lead to deregulation in leptin function that results in maternal disease and clinical studies demonstrate an impact of obesity with an increased risk of a number of diseases in adulthood, including metabolic disease. In this context, leptin deregulation has been implicated in the pathogenesis of GDM. It is well accepted that leptin and LEPR expressions are increased in placentas from GDM, which may be relevant to control fetal homeostasis. Moreover, a role for microRNAs in the regulation of placental growth has been suggested, and expression profiling in the studies has shown expression and gestational changes in microRNA levels that demand functional evaluation. Further investigation is needed to fully elucidate the association of leptin with GDM and to stablish leptin as a biomarker for this pathology or the development of microRNA-based approaches to therapeutic targeting for correcting the abnormal placental growth and cell turnover seen in GDM.

#### Disclosure of interests

The authors declare no conflict of interest.

#### Author details

Pilar Guadix1†, Antonio Pérez-Pérez2†, Teresa Vilariño-García<sup>2</sup> , José L. Dueñas<sup>1</sup> , Julieta Maymó<sup>3</sup> , Cecilia Varone<sup>3</sup> and Víctor Sánchez-Margalet<sup>2</sup> \*

1 Obstetrics and Gynecology Unit, Virgen Macarena University Hospital, University of Seville, Spain

2 Department of Medical Biochemistry and Molecular Biology, and Immunology, Virgen Macarena University Hospital, University of Seville, Seville, Spain

3 Laboratory of Placental Molecular Physiology, Department of Biological Chemistry, School of Sciences, University of Buenos Aires, Argentina

\*Address all correspondence to: margalet@us.es

† These authors contribute equally to this work as first authors

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### References

[1] El husseny MWA, Mamdouh M, Shaban S, Ibrahim Abushouk A, Zaki MMM, Ahmed OM, et al. Adipokines: Potential therapeutic targets for vascular dysfunction in type II diabetes mellitus and obesity. Journal Diabetes Research. 2017;2017:1-11. DOI: 10.1155/ 2017/8095926

[2] Friedman JM, Halaas JL. Leptin and the regulation of body weight in mammals. Nature. 1998;395:763-770. DOI: 10.1038/27376

[3] Pérez-Pérez A, Sánchez-Jiménez F, Maymó J, Dueñas JL, Varone C, Sánchez-Margalet V. Role of leptin in female reproduction. Clinical Chemistry and Laboratory Medicine. 2015;53:15-28. DOI: 10.1515/cclm-2014-0387

[4] Reitman ML, Bi S, Marcus-Samuels B, Gavrilova O. Leptin and its role in pregnancy and fetal development—An overview. Biochemical Society Transactions. 2001;29:68-72

[5] Staun-Ram E, Shalev E. Human trophoblast function during the implantation process. Reproductive Biology and Endocrinology. 2005;3:56. DOI: 10.1186/1477-7827-3-56

[6] Pollheimer J, Knöfler M. Signalling pathways regulating the invasive differentiation of human trophoblasts: A review. Placenta. 2005;26(Suppl A): S21-S30. DOI: 10.1016/j. placenta.2004.11.013

[7] Carson DD, Bagchi I, Dey SK, Enders AC, Fazleabas AT, Lessey BA, et al. Embryo implantation. Developmental Biology. 2000;223:217-237. DOI: 10.1006/dbio.2000.9767

[8] E Davies J, Pollheimer J, Yong HEJ, Kokkinos MI, Kalionis B, Knöfler M, et al. Epithelial-mesenchymal transition during extravillous trophoblast

differentiation. Cell Adhesion & Migration. 2016;10:310-321. DOI: 10.1080/19336918.2016.1170258

[9] Pérez-Pérez A, Guadix P, Maymó J, Dueñas J, Varone C, Fernández-Sánchez M, et al. Insulin and leptin signaling in placenta from gestational diabetic subjects. Hormone and Metabolic Research. 2015;48:62-69. DOI: 10.1055/ s-0035-1559722

Devoto L, et al. Leptin and

Update;6:290-300

reproduction. Human Reproduction

Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

Reproduction. 2006;132:771-780. DOI:

[24] Sir-Petermann T, Recabarren SE, Lobos A, Maliqueo M, Wildt L. Secretory pattern of leptin and LH during lactational amenorrhoea in breastfeeding normal and polycystic ovarian syndrome women. Human Reproduction. 2001;16:244-249

[25] Farooqi IS, Jebb SA, Langmack G, Lawrence E, Cheetham CH, Prentice AM, et al. Effects of recombinant leptin therapy in a child with congenital leptin deficiency. The New England Journal of Medicine. 1999;341:879-884. DOI: 10.1056/NEJM199909163411204

[26] Cervero A, Horcajadas JA, Domínguez F, Pellicer A, Simón C. Leptin system in embryo development and implantation: A protein in search of a function. Reproductive Biomedicine

[27] Kawamura K, Sato N, Fukuda J, Kodama H, Kumagai J, Tanikawa H, et al. Leptin promotes the development of mouse preimplantation embryos in vitro. Endocrinology. 2002;143:

[28] Aplin JD. Implantation, trophoblast differentiation and haemochorial placentation: Mechanistic evidence in vivo and in vitro. Journal of Cell Science. 1991;99(Pt 4):681-692

[29] Schneider H. Ontogenic changes in the nutritive function of the placenta.

[30] Bajoria R, Sooranna SR, Ward BS, Chatterjee R. Prospective function of placental leptin at maternal-fetal interface. Placenta. 2002;23:103-115.

[31] Henson MC, Castracane VD. Leptin in pregnancy: An update. Biology of

Online. 2005;10:217-223

1922-1931. DOI: 10.1210/

Placenta. 1996;17:15-26

DOI: 10.1053/plac.2001.0769

endo.143.5.8818

10.1530/rep.1.01164

[17] Sartori C, Lazzeroni P, Merli S, Patianna VD, Viaroli F, Cirillo F, et al. From placenta to polycystic ovarian syndrome: The role of adipokines. Mediators of Inflammation. 2016;2016: 4981916. DOI: 10.1155/2016/4981916

[18] Louis GW, Greenwald-Yarnell M, Phillips R, Coolen LM, Lehman MN, Myers MG. Molecular mapping of the neural pathways linking leptin to the neuroendocrine reproductive axis. Endocrinology. 2011;152:2302-2310.

[19] Jin L, Zhang S, Burguera BG, Couce ME, Osamura RY, Kulig E, et al. Leptin and leptin receptor expression in rat and mouse pituitary cells. Endocrinology. 2000;141:333-339. DOI: 10.1210/

[20] Archanco M, Muruzábal FJ, Llopiz D, Garayoa M, Gómez-Ambrosi J, Frühbeck G, et al. Leptin expression in the rat ovary depends on estrous cycle. The Journal of Histochemistry and Cytochemistry. 2003;51:1269-1277. DOI:

[21] Karlsson C, Lindell K, Svensson E,

[22] Cioffi JA, Van Blerkom J, Antczak M, Shafer A, Wittmer S, Snodgrass HR.

[23] Ricci AG, Di Yorio MP, Faletti AG. Inhibitory effect of leptin on the rat ovary during the ovulatory process.

The expression of leptin and its receptors in pre-ovulatory human follicles. Molecular Human Reproduction. 1997;3:467-472

10.1177/002215540305101003

Bergh C, Lind P, Billig H, et al. Expression of functional leptin receptors in the human ovary. The Journal of Clinical Endocrinology and Metabolism. 1997;82:4144-4148. DOI:

10.1210/jcem.82.12.4446

111

DOI: 10.1210/en.2011-0096

endo.141.1.7260

[10] Elmquist JK. Anatomic basis of leptin action in the hypothalamus. Frontiers of Hormone Research. 2000; 26:21-41

[11] Zhang Y, Proenca R, Maffei M, Barone M, Leopold L, Friedman JM. Positional cloning of the mouse obese gene and its human homologue. Nature. 1994;372:425-432. DOI: 10.1038/372425a0

[12] Houseknecht KL, Portocarrero CP. Leptin and its receptors: Regulators of whole-body energy homeostasis. Domestic Animal Endocrinology. 1998; 15:457-475

[13] Hoggard N, Haggarty P, Thomas L, Lea RG. Leptin expression in placental and fetal tissues: Does leptin have a functional role? Biochemical Society Transactions. 2001;29:57-63

[14] Masuzaki H, Ogawa Y, Sagawa N, Hosoda K, Matsumoto T, Mise H, et al. Nonadipose tissue production of leptin: Leptin as a novel placenta-derived hormone in humans. Nature Medicine. 1997;3:1029-1033

[15] Acconcia F, Kumar R. Signaling regulation of genomic and nongenomic functions of estrogen receptors. Cancer Letters. 2006;238:1-14. DOI: 10.1016/j. canlet.2005.06.018

[16] González RR, Simón C, Caballero-Campo P, Norman R, Chardonnens D, Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

Devoto L, et al. Leptin and reproduction. Human Reproduction Update;6:290-300

References

2017/8095926

DOI: 10.1038/27376

[1] El husseny MWA, Mamdouh M, Shaban S, Ibrahim Abushouk A, Zaki MMM, Ahmed OM, et al. Adipokines: Potential therapeutic targets for

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

differentiation. Cell Adhesion & Migration. 2016;10:310-321. DOI: 10.1080/19336918.2016.1170258

s-0035-1559722

26:21-41

15:457-475

[9] Pérez-Pérez A, Guadix P, Maymó J, Dueñas J, Varone C, Fernández-Sánchez M, et al. Insulin and leptin signaling in placenta from gestational diabetic subjects. Hormone and Metabolic Research. 2015;48:62-69. DOI: 10.1055/

[10] Elmquist JK. Anatomic basis of leptin action in the hypothalamus. Frontiers of Hormone Research. 2000;

[11] Zhang Y, Proenca R, Maffei M, Barone M, Leopold L, Friedman JM. Positional cloning of the mouse obese gene and its human homologue. Nature. 1994;372:425-432. DOI: 10.1038/372425a0

[12] Houseknecht KL, Portocarrero CP. Leptin and its receptors: Regulators of whole-body energy homeostasis. Domestic Animal Endocrinology. 1998;

[13] Hoggard N, Haggarty P, Thomas L, Lea RG. Leptin expression in placental and fetal tissues: Does leptin have a functional role? Biochemical Society

[14] Masuzaki H, Ogawa Y, Sagawa N, Hosoda K, Matsumoto T, Mise H, et al. Nonadipose tissue production of leptin: Leptin as a novel placenta-derived hormone in humans. Nature Medicine.

[15] Acconcia F, Kumar R. Signaling regulation of genomic and nongenomic functions of estrogen receptors. Cancer Letters. 2006;238:1-14. DOI: 10.1016/j.

[16] González RR, Simón C, Caballero-Campo P, Norman R, Chardonnens D,

Transactions. 2001;29:57-63

1997;3:1029-1033

canlet.2005.06.018

vascular dysfunction in type II diabetes mellitus and obesity. Journal Diabetes Research. 2017;2017:1-11. DOI: 10.1155/

[2] Friedman JM, Halaas JL. Leptin and the regulation of body weight in mammals. Nature. 1998;395:763-770.

[3] Pérez-Pérez A, Sánchez-Jiménez F, Maymó J, Dueñas JL, Varone C, Sánchez-Margalet V. Role of leptin in female reproduction. Clinical Chemistry and Laboratory Medicine. 2015;53:15-28.

[4] Reitman ML, Bi S, Marcus-Samuels B, Gavrilova O. Leptin and its role in pregnancy and fetal development—An

DOI: 10.1515/cclm-2014-0387

overview. Biochemical Society Transactions. 2001;29:68-72

DOI: 10.1186/1477-7827-3-56

S21-S30. DOI: 10.1016/j. placenta.2004.11.013

10.1006/dbio.2000.9767

110

[5] Staun-Ram E, Shalev E. Human trophoblast function during the implantation process. Reproductive Biology and Endocrinology. 2005;3:56.

[6] Pollheimer J, Knöfler M. Signalling pathways regulating the invasive differentiation of human trophoblasts: A review. Placenta. 2005;26(Suppl A):

[7] Carson DD, Bagchi I, Dey SK, Enders AC, Fazleabas AT, Lessey BA, et al. Embryo implantation. Developmental Biology. 2000;223:217-237. DOI:

[8] E Davies J, Pollheimer J, Yong HEJ, Kokkinos MI, Kalionis B, Knöfler M, et al. Epithelial-mesenchymal transition

during extravillous trophoblast

[17] Sartori C, Lazzeroni P, Merli S, Patianna VD, Viaroli F, Cirillo F, et al. From placenta to polycystic ovarian syndrome: The role of adipokines. Mediators of Inflammation. 2016;2016: 4981916. DOI: 10.1155/2016/4981916

[18] Louis GW, Greenwald-Yarnell M, Phillips R, Coolen LM, Lehman MN, Myers MG. Molecular mapping of the neural pathways linking leptin to the neuroendocrine reproductive axis. Endocrinology. 2011;152:2302-2310. DOI: 10.1210/en.2011-0096

[19] Jin L, Zhang S, Burguera BG, Couce ME, Osamura RY, Kulig E, et al. Leptin and leptin receptor expression in rat and mouse pituitary cells. Endocrinology. 2000;141:333-339. DOI: 10.1210/ endo.141.1.7260

[20] Archanco M, Muruzábal FJ, Llopiz D, Garayoa M, Gómez-Ambrosi J, Frühbeck G, et al. Leptin expression in the rat ovary depends on estrous cycle. The Journal of Histochemistry and Cytochemistry. 2003;51:1269-1277. DOI: 10.1177/002215540305101003

[21] Karlsson C, Lindell K, Svensson E, Bergh C, Lind P, Billig H, et al. Expression of functional leptin receptors in the human ovary. The Journal of Clinical Endocrinology and Metabolism. 1997;82:4144-4148. DOI: 10.1210/jcem.82.12.4446

[22] Cioffi JA, Van Blerkom J, Antczak M, Shafer A, Wittmer S, Snodgrass HR. The expression of leptin and its receptors in pre-ovulatory human follicles. Molecular Human Reproduction. 1997;3:467-472

[23] Ricci AG, Di Yorio MP, Faletti AG. Inhibitory effect of leptin on the rat ovary during the ovulatory process.

Reproduction. 2006;132:771-780. DOI: 10.1530/rep.1.01164

[24] Sir-Petermann T, Recabarren SE, Lobos A, Maliqueo M, Wildt L. Secretory pattern of leptin and LH during lactational amenorrhoea in breastfeeding normal and polycystic ovarian syndrome women. Human Reproduction. 2001;16:244-249

[25] Farooqi IS, Jebb SA, Langmack G, Lawrence E, Cheetham CH, Prentice AM, et al. Effects of recombinant leptin therapy in a child with congenital leptin deficiency. The New England Journal of Medicine. 1999;341:879-884. DOI: 10.1056/NEJM199909163411204

[26] Cervero A, Horcajadas JA, Domínguez F, Pellicer A, Simón C. Leptin system in embryo development and implantation: A protein in search of a function. Reproductive Biomedicine Online. 2005;10:217-223

[27] Kawamura K, Sato N, Fukuda J, Kodama H, Kumagai J, Tanikawa H, et al. Leptin promotes the development of mouse preimplantation embryos in vitro. Endocrinology. 2002;143: 1922-1931. DOI: 10.1210/ endo.143.5.8818

[28] Aplin JD. Implantation, trophoblast differentiation and haemochorial placentation: Mechanistic evidence in vivo and in vitro. Journal of Cell Science. 1991;99(Pt 4):681-692

[29] Schneider H. Ontogenic changes in the nutritive function of the placenta. Placenta. 1996;17:15-26

[30] Bajoria R, Sooranna SR, Ward BS, Chatterjee R. Prospective function of placental leptin at maternal-fetal interface. Placenta. 2002;23:103-115. DOI: 10.1053/plac.2001.0769

[31] Henson MC, Castracane VD. Leptin in pregnancy: An update. Biology of

Reproduction. 2006;74:218-229. DOI: 10.1095/biolreprod.105.045120

[32] Ahima RS, Prabakaran D, Mantzoros C, Qu D, Lowell B, Maratos-Flier E, et al. Role of leptin in the neuroendocrine response to fasting. Nature. 1996;382:250-252. DOI: 10.1038/382250a0

[33] Bjørbaek C, Uotani S, da Silva B, Flier JS. Divergent signaling capacities of the long and short isoforms of the leptin receptor. The Journal of Biological Chemistry. 1997;272:32686-32695

[34] Banks AS, Davis SM, Bates SH, Myers MG. Activation of downstream signals by the long form of the leptin receptor. The Journal of Biological Chemistry. 2000;275:14563-14572

[35] Wyrwoll CS, Mark PJ, Waddell BJ. Directional secretion and transport of leptin and expression of leptin receptor isoforms in human placental BeWo cells. Molecular and Cellular Endocrinology. 2005;241:73-79. DOI: 10.1016/j.mce.2005.05.003

[36] Pérez-Pérez A, Maymó J, Gambino Y, Dueñas JL, Goberna R, Varone C, et al. Leptin stimulates protein synthesis-activating translation machinery in human trophoblastic cells. Biology of Reproduction. 2009;81: 826-832. DOI: 10.1095/ biolreprod.109.076513

[37] Toro AR, Maymó JL, Ibarbalz FM, Pérez-Pérez A, Maskin B, Faletti AG, et al. Leptin is an anti-apoptotic effector in placental cells involving p53 downregulation. PLoS One. 2014;9: e99187. DOI: 10.1371/journal. pone.0099187

[38] Toro AR, Pérez-Pérez A, Corrales Gutiérrez I, Sánchez-Margalet V, Varone CL. Mechanisms involved in p53 downregulation by leptin in trophoblastic cells. Placenta. 2015;36:

1266-1275. DOI: 10.1016/j. placenta.2015.08.017

[39] Pérez-Pérez A, Toro A, Vilariño-Garcia T, Guadix P, Maymó J, Dueñas JL, et al. Leptin protects placental cells from apoptosis induced by acidic stress. Cell and Tissue Research. 2018. DOI: 10.1007/s00441-018-2940-9

containing protein tyrosine

DOI: 10.1210/en.2009-0166

sj.embor.embor939

221-227. DOI: 10.1016/j. mce.2010.10.014

placenta.2007.11.002

159-169. DOI: 10.1111/ j.1600-0897.2010.00837.x

113

disease. American Journal of

The placenta: Transcriptional,

phosphatase-2, is a crucial mediator of exogenous insulin-like growth factor signaling to human trophoblast. Endocrinology. 2009;150:4744-4754.

Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

> [52] Pérez-Pérez A, Maymó J, Dueñas JL, Goberna R, Calvo JC, Varone C, et al.

> Biochemistry and Biophysics. 2008;477:

[53] Pérez-Pérez A, Gambino Y, Maymó J, Goberna R, Fabiani F, Varone C, et al. MAPK and PI3K activities are required for leptin stimulation of protein synthesis in human trophoblastic cells. Biochemical and Biophysical Research Communications. 2010;396:956-960. DOI: 10.1016/j.bbrc.2010.05.031

[54] Fumagalli S, Totty NF, Hsuan JJ, Courtneidge SA. A target for Src in mitosis. Nature. 1994;368:871-874. DOI:

[55] Taylor SJ, Shalloway D. An RNAbinding protein associated with Src through its SH2 and SH3 domains in mitosis. Nature. 1994;368:867-871. DOI:

[56] Sánchez-Margalet V, Martín-Romero C, Santos-Alvarez J, Goberna R, Najib S, Gonzalez-Yanes C. Role of leptin as an immunomodulator of blood mononuclear cells: Mechanisms of action. Clinical and Experimental Immunology. 2003;133:11-19

[57] Kotlabova K, Doucha J,

10.1016/j.jri.2011.02.006

1998;6:197-204

Hromadnikova I. Placental-specific microRNA in maternal circulation— Identification of appropriate pregnancyassociated microRNAs with diagnostic potential. Journal of Reproductive Immunology. 2011;89:185-191. DOI:

[58] Hutter H, Hammer A, Dohr G, Hunt JS. HLA expression at the maternal-fetal interface. Developmental Immunology.

[59] Lappas M, Rice GE. Phospholipase

A2 isozymes in pregnancy and

Leptin prevents apoptosis of trophoblastic cells by activation of MAPK pathway. Archives of

390-395. DOI: 10.1016/j.

abb.2008.06.015

10.1038/368871a0

10.1038/368867a0

[46] Huppertz B, Kadyrov M, Kingdom JCP. Apoptosis and its role in the trophoblast. American Journal of Obstetrics and Gynecology. 2006;195: 29-39. DOI: 10.1016/j.ajog.2005.07.039

[47] Saba-El-Leil MK, Vella FDJ, Vernay B, Voisin L, Chen L, Labrecque N, et al. An essential function of the mitogenactivated protein kinase Erk2 in mouse trophoblast development. EMBO Reports. 2003;4:964-968. DOI: 10.1038/

[48] Sánchez-Jiménez F, Pérez-Pérez A, González-Yanes C, Najib S, Varone CL, Sánchez-Margalet V. Leptin receptor activation increases Sam68 tyrosine phosphorylation and expression in human trophoblastic cells. Molecular and Cellular Endocrinology. 2011;332:

[49] Heazell AEP, Lacey HA, Jones CJP, Huppertz B, Baker PN, Crocker IP. Effects of oxygen on cell turnover and expression of regulators of apoptosis in human placental trophoblast. Placenta. 2008;29:175-186. DOI: 10.1016/j.

[50] Sharp AN, Heazell AEP, Crocker IP, Mor G. Placental apoptosis in health and

Reproductive Immunology. 2010;64:

[51] Maltepe E, Bakardjiev AI, Fisher SJ.

epigenetic, and physiological integration during development. The Journal of Clinical Investigation. 2010;120: 1016-1025. DOI: 10.1172/JCI41211

[40] Pérez-Pérez A, Toro AR, Vilarino-Garcia T, Guadix P, Maymó JL, Dueñas JL, et al. Leptin reduces apoptosis triggered by high temperature in human placental villous explants: The role of the p53 pathway. Placenta. 2016;42: 106-113. DOI: 10.1016/j. placenta.2016.03.009

[41] Magariños MP, Sánchez-Margalet V, Kotler M, Calvo JC, Varone CL. Leptin promotes cell proliferation and survival of trophoblastic cells. Biology of Reproduction. 2007;76:203-210. DOI: 10.1095/biolreprod.106.051391

[42] Genbacev O, Miller RK. Postimplantation differentiation and proliferation of cytotrophoblast cells: In vitro models—A review. Placenta. 2000;21(Suppl A):S45-S49

[43] Forbes K, Westwood M, Baker PN, Aplin JD. Insulin-like growth factor I and II regulate the life cycle of trophoblast in the developing human placenta. American Journal of Physiology. Cell Physiology. 2008;294: C1313-C1322. DOI: 10.1152/ ajpcell.00035.2008

[44] Forbes K, Souquet B, Garside R, Aplin JD, Westwood M. Transforming growth factor-{beta} (TGF{beta}) receptors I/II differentially regulate TGF {beta}1 and IGF-binding protein-3 mitogenic effects in the human placenta. Endocrinology. 2010;151: 1723-1731. DOI: 10.1210/en.2009-0896

[45] Forbes K, West G, Garside R, Aplin JD, Westwood M. The protein-tyrosine phosphatase, SRC homology-2 domain

Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

containing protein tyrosine phosphatase-2, is a crucial mediator of exogenous insulin-like growth factor signaling to human trophoblast. Endocrinology. 2009;150:4744-4754. DOI: 10.1210/en.2009-0166

Reproduction. 2006;74:218-229. DOI: 10.1095/biolreprod.105.045120

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

1266-1275. DOI: 10.1016/j. placenta.2015.08.017

10.1007/s00441-018-2940-9

106-113. DOI: 10.1016/j. placenta.2016.03.009

[39] Pérez-Pérez A, Toro A, Vilariño-Garcia T, Guadix P, Maymó J, Dueñas JL, et al. Leptin protects placental cells from apoptosis induced by acidic stress. Cell and Tissue Research. 2018. DOI:

[40] Pérez-Pérez A, Toro AR, Vilarino-Garcia T, Guadix P, Maymó JL, Dueñas JL, et al. Leptin reduces apoptosis triggered by high temperature in human placental villous explants: The role of the p53 pathway. Placenta. 2016;42:

[41] Magariños MP, Sánchez-Margalet V, Kotler M, Calvo JC, Varone CL. Leptin promotes cell proliferation and survival of trophoblastic cells. Biology of Reproduction. 2007;76:203-210. DOI: 10.1095/biolreprod.106.051391

[42] Genbacev O, Miller RK. Postimplantation differentiation and proliferation of cytotrophoblast cells: In vitro models—A review. Placenta. 2000;21(Suppl A):S45-S49

[43] Forbes K, Westwood M, Baker PN, Aplin JD. Insulin-like growth factor I and II regulate the life cycle of trophoblast in the developing human placenta. American Journal of

Physiology. Cell Physiology. 2008;294:

[44] Forbes K, Souquet B, Garside R, Aplin JD, Westwood M. Transforming growth factor-{beta} (TGF{beta}) receptors I/II differentially regulate TGF {beta}1 and IGF-binding protein-3 mitogenic effects in the human placenta. Endocrinology. 2010;151: 1723-1731. DOI: 10.1210/en.2009-0896

[45] Forbes K, West G, Garside R, Aplin JD, Westwood M. The protein-tyrosine phosphatase, SRC homology-2 domain

C1313-C1322. DOI: 10.1152/

ajpcell.00035.2008

Mantzoros C, Qu D, Lowell B, Maratos-Flier E, et al. Role of leptin in the neuroendocrine response to fasting. Nature. 1996;382:250-252. DOI:

[33] Bjørbaek C, Uotani S, da Silva B, Flier JS. Divergent signaling capacities of the long and short isoforms of the leptin receptor. The Journal of Biological Chemistry. 1997;272:32686-32695

[34] Banks AS, Davis SM, Bates SH, Myers MG. Activation of downstream signals by the long form of the leptin receptor. The Journal of Biological Chemistry. 2000;275:14563-14572

[35] Wyrwoll CS, Mark PJ, Waddell BJ. Directional secretion and transport of leptin and expression of leptin receptor isoforms in human placental BeWo cells. Molecular and Cellular

Endocrinology. 2005;241:73-79. DOI:

[36] Pérez-Pérez A, Maymó J, Gambino Y, Dueñas JL, Goberna R, Varone C, et al. Leptin stimulates protein synthesis-activating translation

machinery in human trophoblastic cells. Biology of Reproduction. 2009;81:

[37] Toro AR, Maymó JL, Ibarbalz FM, Pérez-Pérez A, Maskin B, Faletti AG, et al. Leptin is an anti-apoptotic effector

[38] Toro AR, Pérez-Pérez A, Corrales Gutiérrez I, Sánchez-Margalet V, Varone CL. Mechanisms involved in p53

trophoblastic cells. Placenta. 2015;36:

in placental cells involving p53 downregulation. PLoS One. 2014;9: e99187. DOI: 10.1371/journal.

downregulation by leptin in

10.1016/j.mce.2005.05.003

826-832. DOI: 10.1095/ biolreprod.109.076513

pone.0099187

112

[32] Ahima RS, Prabakaran D,

10.1038/382250a0

[46] Huppertz B, Kadyrov M, Kingdom JCP. Apoptosis and its role in the trophoblast. American Journal of Obstetrics and Gynecology. 2006;195: 29-39. DOI: 10.1016/j.ajog.2005.07.039

[47] Saba-El-Leil MK, Vella FDJ, Vernay B, Voisin L, Chen L, Labrecque N, et al. An essential function of the mitogenactivated protein kinase Erk2 in mouse trophoblast development. EMBO Reports. 2003;4:964-968. DOI: 10.1038/ sj.embor.embor939

[48] Sánchez-Jiménez F, Pérez-Pérez A, González-Yanes C, Najib S, Varone CL, Sánchez-Margalet V. Leptin receptor activation increases Sam68 tyrosine phosphorylation and expression in human trophoblastic cells. Molecular and Cellular Endocrinology. 2011;332: 221-227. DOI: 10.1016/j. mce.2010.10.014

[49] Heazell AEP, Lacey HA, Jones CJP, Huppertz B, Baker PN, Crocker IP. Effects of oxygen on cell turnover and expression of regulators of apoptosis in human placental trophoblast. Placenta. 2008;29:175-186. DOI: 10.1016/j. placenta.2007.11.002

[50] Sharp AN, Heazell AEP, Crocker IP, Mor G. Placental apoptosis in health and disease. American Journal of Reproductive Immunology. 2010;64: 159-169. DOI: 10.1111/ j.1600-0897.2010.00837.x

[51] Maltepe E, Bakardjiev AI, Fisher SJ. The placenta: Transcriptional, epigenetic, and physiological integration during development. The Journal of Clinical Investigation. 2010;120: 1016-1025. DOI: 10.1172/JCI41211

[52] Pérez-Pérez A, Maymó J, Dueñas JL, Goberna R, Calvo JC, Varone C, et al. Leptin prevents apoptosis of trophoblastic cells by activation of MAPK pathway. Archives of Biochemistry and Biophysics. 2008;477: 390-395. DOI: 10.1016/j. abb.2008.06.015

[53] Pérez-Pérez A, Gambino Y, Maymó J, Goberna R, Fabiani F, Varone C, et al. MAPK and PI3K activities are required for leptin stimulation of protein synthesis in human trophoblastic cells. Biochemical and Biophysical Research Communications. 2010;396:956-960. DOI: 10.1016/j.bbrc.2010.05.031

[54] Fumagalli S, Totty NF, Hsuan JJ, Courtneidge SA. A target for Src in mitosis. Nature. 1994;368:871-874. DOI: 10.1038/368871a0

[55] Taylor SJ, Shalloway D. An RNAbinding protein associated with Src through its SH2 and SH3 domains in mitosis. Nature. 1994;368:867-871. DOI: 10.1038/368867a0

[56] Sánchez-Margalet V, Martín-Romero C, Santos-Alvarez J, Goberna R, Najib S, Gonzalez-Yanes C. Role of leptin as an immunomodulator of blood mononuclear cells: Mechanisms of action. Clinical and Experimental Immunology. 2003;133:11-19

[57] Kotlabova K, Doucha J, Hromadnikova I. Placental-specific microRNA in maternal circulation— Identification of appropriate pregnancyassociated microRNAs with diagnostic potential. Journal of Reproductive Immunology. 2011;89:185-191. DOI: 10.1016/j.jri.2011.02.006

[58] Hutter H, Hammer A, Dohr G, Hunt JS. HLA expression at the maternal-fetal interface. Developmental Immunology. 1998;6:197-204

[59] Lappas M, Rice GE. Phospholipase A2 isozymes in pregnancy and

parturition. Prostaglandins, Leukotrienes, and Essential Fatty Acids. 2004;70:87-100

[60] Rice GE. Cytokines and the initiation of parturition. Frontiers of Hormone Research. 2001;27:113-146

[61] Lappas M, Yee K, Permezel M, Rice GE. Release and regulation of leptin, resistin and adiponectin from human placenta, fetal membranes, and maternal adipose tissue and skeletal muscle from normal and gestational diabetes mellitus-complicated pregnancies. The Journal of Endocrinology. 2005;186:457-465. DOI: 10.1677/joe.1.06227

[62] Lam QLK, Lu L. Role of leptin in immunity. Cellular & Molecular Immunology. 2007;4:1-13

[63] Fernández-Riejos P, Najib S, Santos-Alvarez J, Martín-Romero C, Pérez-Pérez A, González-Yanes C, et al. Role of leptin in the activation of immune cells. Mediators of Inflammation. 2010; 2010:568343. DOI: 10.1155/2010/568343

[64] Fontana VA, Sanchez M, Cebral E, Calvo JC. Interleukin-1 beta regulates metalloproteinase activity and leptin secretion in a cytotrophoblast model. Biocell. 2010;34:37-43

[65] Fontana VA, Sanchez M, Cebral E, Calvo JC. Interferon-gamma inhibits metalloproteinase activity and cytotrophoblast cell migration. American Journal of Reproductive Immunology. 2010;64:20-26. DOI: 10.1111/j.1600-0897.2010.00816.x

[66] Soh EB, Mitchell MD, Keelan JA. Does leptin exhibit cytokine-like properties in tissues of pregnancy? American Journal of Reproductive Immunology. 2000;43:292-298

[67] Cameo P, Bischof P, Calvo JC. Effect of leptin on progesterone, human chorionic gonadotropin, and

interleukin-6 secretion by human term trophoblast cells in culture. Biology of Reproduction. 2003;68:472-477

[68] Lappas M, Permezel M, Georgiou HM, Rice GE. Nuclear factor kappa B regulation of proinflammatory cytokines in human gestational tissues in vitro. Biology of Reproduction. 2002; 67:668-673

[69] Barrientos G, Toro A, Moschansky P, Cohen M, Garcia MG, Rose M, et al. Leptin promotes HLA-G expression on placental trophoblasts via the MEK/Erk and PI3K signaling pathways. Placenta. 2015;36:419-426. DOI: 10.1016/j. placenta.2015.01.006

[70] Pérez-Pérez A, Maymó JL, Gambino YP, Guadix P, Dueñas JL, Varone CL, et al. Activated translation signaling in placenta from pregnant women with gestational diabetes mellitus: Possible role of leptin. Hormone and Metabolic Research. 2013;45:436-442. DOI: 10.1055/s-0032-1333276

[71] Qiu C, Williams MA, Vadachkoria S, Frederick IO, Luthy DA. Increased maternal plasma leptin in early pregnancy and risk of gestational diabetes mellitus. Obstetrics and Gynecology. 2004;103:519-525. DOI: 10.1097/01.AOG.0000113621.53602.7a

[72] Barnes-Powell LL. Infants of diabetic mothers: The effects of hyperglycemia on the fetus and neonate. Neonatal Network. 2007;26:283-290. DOI: 10.1891/0730-0832.26.5.283

[73] Uzelac PS, Li X, Lin J, Neese LD, Lin L, Nakajima ST, et al. Dysregulation of leptin and testosterone production and their receptor expression in the human placenta with gestational diabetes mellitus. Placenta. 2010;31:581-588. DOI: 10.1016/j.placenta.2010.04.002

[74] Ferrara A. Increasing prevalence of gestational diabetes mellitus: A public health perspective. Diabetes Care. 2007; Leptin and Gestational Diabetes Mellitus DOI: http://dx.doi.org/10.5772/intechopen.84885

30(Supp. 2):S141-S146. DOI: 10.2337/ dc07-s206

parturition. Prostaglandins,

[60] Rice GE. Cytokines and the initiation of parturition. Frontiers of Hormone Research. 2001;27:113-146

2004;70:87-100

10.1677/joe.1.06227

Leukotrienes, and Essential Fatty Acids.

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

interleukin-6 secretion by human term trophoblast cells in culture. Biology of Reproduction. 2003;68:472-477

[68] Lappas M, Permezel M, Georgiou HM, Rice GE. Nuclear factor kappa B regulation of proinflammatory

cytokines in human gestational tissues in vitro. Biology of Reproduction. 2002;

[69] Barrientos G, Toro A, Moschansky P, Cohen M, Garcia MG, Rose M, et al. Leptin promotes HLA-G expression on placental trophoblasts via the MEK/Erk and PI3K signaling pathways. Placenta. 2015;36:419-426. DOI: 10.1016/j.

[70] Pérez-Pérez A, Maymó JL, Gambino YP, Guadix P, Dueñas JL, Varone CL, et al. Activated translation signaling in placenta from pregnant women with gestational diabetes mellitus: Possible role of leptin. Hormone and Metabolic Research. 2013;45:436-442. DOI:

[71] Qiu C, Williams MA, Vadachkoria S, Frederick IO, Luthy DA. Increased maternal plasma leptin in early pregnancy and risk of gestational diabetes mellitus. Obstetrics and Gynecology. 2004;103:519-525. DOI: 10.1097/01.AOG.0000113621.53602.7a

[72] Barnes-Powell LL. Infants of diabetic mothers: The effects of

hyperglycemia on the fetus and neonate. Neonatal Network. 2007;26:283-290. DOI: 10.1891/0730-0832.26.5.283

[73] Uzelac PS, Li X, Lin J, Neese LD, Lin L, Nakajima ST, et al. Dysregulation of leptin and testosterone production and their receptor expression in the human placenta with gestational diabetes mellitus. Placenta. 2010;31:581-588. DOI: 10.1016/j.placenta.2010.04.002

[74] Ferrara A. Increasing prevalence of gestational diabetes mellitus: A public health perspective. Diabetes Care. 2007;

67:668-673

placenta.2015.01.006

10.1055/s-0032-1333276

[61] Lappas M, Yee K, Permezel M, Rice GE. Release and regulation of leptin, resistin and adiponectin from human placenta, fetal membranes, and maternal adipose tissue and skeletal muscle from normal and gestational diabetes mellitus-complicated pregnancies. The Journal of

Endocrinology. 2005;186:457-465. DOI:

[62] Lam QLK, Lu L. Role of leptin in immunity. Cellular & Molecular Immunology. 2007;4:1-13

[63] Fernández-Riejos P, Najib S, Santos-Alvarez J, Martín-Romero C, Pérez-Pérez A, González-Yanes C, et al. Role of leptin in the activation of immune cells. Mediators of Inflammation. 2010; 2010:568343. DOI: 10.1155/2010/568343

[64] Fontana VA, Sanchez M, Cebral E, Calvo JC. Interleukin-1 beta regulates metalloproteinase activity and leptin secretion in a cytotrophoblast model.

[65] Fontana VA, Sanchez M, Cebral E, Calvo JC. Interferon-gamma inhibits metalloproteinase activity and cytotrophoblast cell migration. American Journal of Reproductive Immunology. 2010;64:20-26. DOI: 10.1111/j.1600-0897.2010.00816.x

[66] Soh EB, Mitchell MD, Keelan JA. Does leptin exhibit cytokine-like properties in tissues of pregnancy? American Journal of Reproductive Immunology. 2000;43:292-298

[67] Cameo P, Bischof P, Calvo JC. Effect of leptin on progesterone, human chorionic gonadotropin, and

Biocell. 2010;34:37-43

114

[75] Lee AJ, Hiscock RJ, Wein P, Walker SP, Permezel M. Gestational diabetes mellitus: Clinical predictors and longterm risk of developing typ. 2 diabetes: A retrospective cohort study using survival analysis. Diabetes Care. 2007;30:878-883. DOI: 10.2337/ dc06-1816

[76] Thadhani R, Powe CE, Tjoa ML, Khankin E, Ye J, Ecker J, et al. Firsttrimester follistatin-like-3 levels in pregnancies complicated by subsequent gestational diabetes mellitus. Diabetes Care. 2010;33:664-669. DOI: 10.2337/ dc09-1745

[77] Ericsson A, Säljö K, Sjöstrand E, Jansson N, Prasad PD, Powell TL, et al. Brief hyperglycaemia in the early pregnant rat increases fetal weight at term by stimulating placental growth and affecting placental nutrient transport. The Journal of Physiology. 2007;581:1323-1332. DOI: 10.1113/ jphysiol.2007.131185

[78] Taricco E, Radaelli T, Nobile de Santis MS, Cetin I. Foetal and placental weights in relation to maternal characteristics in gestational diabetes. Placenta. 2003;24:343-347

[79] Desoye G, Hauguel-de Mouzon S. The human placenta in gestational diabetes mellitus. The insulin and cytokine network. Diabetes Care. 2007; 30(Supp. 2):S120-S126. DOI: 10.2337/ dc07-s203

[80] Araújo JR, Keating E, Martel F. Impact of gestational diabetes mellitus in the maternal-to-fetal transport of nutrients. Current Diabetes Reports. 2015;15:569. DOI: 10.1007/s11892-014- 0569-y

[81] Powe CE. Early pregnancy biochemical predictors of gestational diabetes mellitus. Current Diabetes

Reports. 2017;17:12. DOI: 10.1007/ s11892-017-0834-y

[82] Iciek R, Wender-Ozegowska E, Zawiejska A, Mikolajczak P, Mrozikiewicz PM, Pietryga M, et al. Placental leptin and its receptor genes expression in pregnancies complicated by typ. 1 diabetes. Journal of Physiology and Pharmacology. 2013;64:579-585

[83] Lepercq J, Cauzac M, Lahlou N, Timsit J, Girard J, Auwerx J, et al. Overexpression of placental leptin in diabetic pregnancy: A critical role for insulin. Diabetes. 1998;47:847-850

[84] Côté S, Gagné-Ouellet V, Guay SP, Allard C, Houde AA, Perron P, et al. PPARGC1α gene DNA methylation variations in human placenta mediate the link between maternal hyperglycemia and leptin levels in newborns. Clinical Epigenetics. 2016;8: 72. DOI: 10.1186/s13148-016-0239-9

[85] Miehle K, Stepan H, Fasshauer M. Leptin, adiponectin and other adipokines in gestational diabetes mellitus and pre-eclampsia. Clinical Endocrinology. 2012;76:2-11. DOI: 10.1111/j.1365-2265.2011.04234.x

[86] Pérez-Pérez A, Maymó J, Gambino Y, Guadix P, Dueñas JL, Varone C, et al. Insulin enhances leptin expression in human trophoblastic cells. Biology of Reproduction. 2013;89:20. DOI: 10.1095/biolreprod.113.109348

[87] Bednar AD, Beardall MK, Brace RA, Cheung CY. Differential expression and regional distribution of aquaporins in amnion of normal and gestational diabetic pregnancies. Physiological Reports. 2015;3:e12320. DOI: 10.14814/ phy2.12320

[88] Castro Parodi M, Farina M, Dietrich V, Abán C, Szpilbarg N, Zotta E, et al. Evidence for insulin-mediated control of AQP9 expression in human placenta.

Placenta. 2011;32:1050-1056. DOI: 10.1016/j.placenta.2011.09.022

[89] Vilariño-García T, Pérez-Pérez A, Dietrich V, Guadix P, Dueñas JL, Varone CL, et al. Leptin upregulates aquaporin 9 expression in human placenta in vitro. Gynecological Endocrinology. 2018;34:175-177. DOI: 10.1080/09513590.2017.1380184

[90] Bernstein E, Kim SY, Carmell MA, Murchison EP, Alcorn H, Li MZ, et al. Dicer is essential for mouse development. Nature Genetics. 2003;35: 215-217. DOI: 10.1038/ng1253

[91] Yang WJ, Yang DD, Na S, Sandusky GE, Zhang Q, Zhao G. Dicer is required for embryonic angiogenesis during mouse development. The Journal of Biological Chemistry. 2005;280: 9330-9335. DOI: 10.1074/jbc. M413394200

[92] Forbes K, Farrokhnia F, Aplin JD, Westwood M. Dicer-dependent miRNAs provide an endogenous restraint on cytotrophoblast proliferation. Placenta. 2012;33:581-585. DOI: 10.1016/j.placenta.2012.03.006

[93] Garibotto G, Russo R, Franceschini R, Robaudo C, Saffioti S, Sofia A, et al. Inter-organ leptin exchange in humans. Biochemical and Biophysical Research Communications. 1998;247:504-509. DOI: 10.1006/bbrc.1998.8819

[94] Misra VK, Straughen JK, Trudeau S. Maternal serum leptin during pregnancy and infant birth weight: The influence of maternal overweight and obesity. Obesity (Silver Spring). 2013;21: 1064-1069. DOI: 10.1002/oby.20128

[95] Tessier DR, Ferraro ZM, Gruslin A. Role of leptin in pregnancy: Consequences of maternal obesity. Placenta. 2013;34:205-211. DOI: 10.1016/j.placenta.2012.11.035

[96] Farley DM, Choi J, Dudley DJ, Li C, Jenkins SL, Myatt L, et al. Placental amino acid transport and placental leptin resistance in pregnancies complicated by maternal obesity. Placenta. 2010;31:718-724. DOI: 10.1016/j.placenta.2010.06.006

[97] Dundar NO, Anal O, Dundar B, Ozkan H, Caliskan S, Büyükgebiz A. Longitudinal investigation of the relationship between breast milk leptin levels and growth in breast-fed infants. Journal of Pediatric Endocrinology & Metabolism. 2005;18:181-187

### *Edited by Amita Ray*

This book on gestational diabetes does not claim to cover all aspects of this complex and ever-evolving medical condition. It is an attempt by the group of authors to provide an overview, highlight important features, and bring to light certain recent advances in the diagnosis, screening, and understanding of gestational diabetes mellitus. As the book provides an overview of the condition, we are sure that reading it would provide medical undergraduates and postgraduates a quick revision for their exams. The current concepts section of the book may inspire more exploration into this area.It has been a pleasure to work with experts, both senior and junior, for this endeavor but we are particularly grateful to the publisher IntechOpen who have shown commitment and perseverance in completing this work. This new book deserves to be a success and we are sure it will be.

Published in London, UK © 2020 IntechOpen © eriksvoboda / iStock

Gestational Diabetes Mellitus - An Overview with Some Recent Advances

Gestational Diabetes Mellitus

An Overview with Some Recent Advances

*Edited by Amita Ray*