**11. Reference values in neonates: insulin resistance/sensitivity markers**

Our group has defined reference values for insulin resistance/sensitivity markers in neonates [59]. These ranges were obtained considering strict criteria at birth, as only term, normoweight, appropriate for gestational age, and without foetal distress (Apgar test evaluation) neonates whose mothers had normal glucose tolerance (O'Sullivan test evaluation) were studied [61]. The insulin resistance/sensitivity was calculated by the following indexes: quantitative insulin sensitivity check index (QUICKI), using the formula: 1/[(log Insulin)(μUI/mL) + (log Glucose) (mg/dL)]; homeostatic model assessment-insulin resistance (HOMA-IR), calculated as: Glucose (mmol/L) × Insulin (μUI/mL)/22.5.

Taking these criteria into account, the following **hypothesis** was assessed: Term, normoweight, without foetal-distress neonates, presenting high cortisol and insulin levels have altered insulin sensitivity and other hormonal markers (GH, IGF-1). These effects can be modified by maternal glucose tolerance during gestation.

The following **aims** were established: (i) to define the anthropometric, hormonal and insulin sensitivity/resistance markers in a wide cohort of term, normoweight, without foetal-distress neonates; (ii) to know the normality of these parameters with respect to the reference ones; (iii) to define the prevalence of insulin resistance in these neonates; (iv) to know whether the association of high insulin and cortisol levels can explain the insulin resistance/sensitivity in these neonates; (v) to study the effect of maternal glucose tolerance during pregnancy on the anthropometric and insulin resistance markers of those neonates; and (vi) to know how the maternal diet quality during gestation can affect the parameters studied in these neonates.

The main reason that led us to perform this study was the current increase in obesity and type 2 diabetes mellitus, especially in young populations. The early diagnosis of the insulin sensitivity affection will allow us to apply corrective and therapeutic measures in order to reduce the chronicity of the insulin resistance and its clinical posterior manifestations.

Taking into account the reference values for neonates [59], the cut-off point for high insulin concentrations (percentile 75, P75) was set up at 6.4 μUI/mL for females and at 4.8 μUI/mL for males. In the case of cortisol, the cut-off point for high levels (percentile 75, P75) was set up at 9.7 μg/dL for females and 9.4 μg/dL for males.

#### **12. General data of neonates from Merida study**

**Table 3** shows the general characteristics of the studied population.


Data are means ± standard deviations; BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor 1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR, homeostatic model assessment-insulin resistance.

**Table 3.** Characteristics of the studied population: term, normoweight neonates without foetal distress.

Of the 178 neonates studied, 98 were females and 80 males. All of them were Caucasic, singleton, term, normoweight and without foetal distress. The study was performed in accordance with the Declaration of Helsinki and approved by the Management and Ethical Committee of the Merida Hospital. From the 178 mothers, 156 were screened for GD by the O'Sullivan test [61] between weeks 24 and 28 of pregnancy, and 33% had impaired glucose tolerance (IGT). There were 22 mothers who could not be screened.

anthropometric and insulin resistance markers of those neonates; and (vi) to know how the maternal diet quality during gestation can affect the parameters studied in these neonates.

The main reason that led us to perform this study was the current increase in obesity and type 2 diabetes mellitus, especially in young populations. The early diagnosis of the insulin sensitivity affection will allow us to apply corrective and therapeutic measures in order to reduce the chronicity of the insulin resistance and its clinical posterior manifestations.

Taking into account the reference values for neonates [59], the cut-off point for high insulin concentrations (percentile 75, P75) was set up at 6.4 μUI/mL for females and at 4.8 μUI/mL for males. In the case of cortisol, the cut-off point for high levels (percentile 75, P75) was set up at

**Minimum Maximum**

9.7 μg/dL for females and 9.4 μg/dL for males.

*Mothers*

*Neonates*

BMI (kg/m2

Ponderal index (kg/m3

**12. General data of neonates from Merida study**

80 Umbilical Cord Blood Banking for Clinical Application and Regenerative Medicine

**Table 3** shows the general characteristics of the studied population.

Age (years) 30.33 ± 5.24 16 40 Glucose (mg/dL) 83.63 ± 6.72 64.0 101.0

Gestational age (weeks) 39.85 ± 1.10 37 42 Weight (g) 3301 ± 331 2520 3990 Length (cm) 50.0 ± 1.38 44.0 53.0

Cephalic perimeter (cm) 34.19 ± 1.35 30.0 37.0 Thoracic perimeter (cm) 33.66 ± 1.43 30.0 39.0 Apgar 1 8.99 ± 0.72 7 10 Apgar 2 9.95 ± 0.29 9 10 Glucose (mg/dL) 78.23 ± 38.39 18 233 Insulin (μIU/mL) 6.57 ± 8.58 0.2 67.50 Cortisol (μg/dL) 7.54 ± 3.55 2.78 24.15 GH (ng/mL) 15.84 ± 10.19 0.6 73.1 IGF-1 (ng/mL) 57.7 ± 26.31 5.0 232.5 QUICKI 0.43 ± 0.12 0.26 1.18 HOMA-IR 1.53 ± 2.78 0.02 16.73 Glucose/insulin 29.26 ± 43.90 0.79 370.0 Insulin/cortisol 0.99 ± 1.40 0.02 11.05

) 13.19 ± 1.12 10.08 15.80

Data are means ± standard deviations; BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor 1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR, homeostatic model assessment-insulin resistance.

**Table 3.** Characteristics of the studied population: term, normoweight neonates without foetal distress.

) 26.41 ± 2.39 20.16 33.22


Data are means ± standard deviations; BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor-1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR, homeostatic model assessment-IR; P: percentile; NS, not significant; ND, not determined.

**Table 4.** Characteristics of the studied population according to the insulin concentration.

The general anthropometric data found were quite similar to those shown in previous studies [62, 63] with mean values of normality, clearly suggesting the absence of maternal-placental malnutrition. The mean values found in hormonal markers agree with those used as reference values in neonates [59]. Glycaemia in neonates is quite variable even in populations where distress and other factors are well controlled [59, 64]. HOMA-IR and QUICKI are usually studied in adults [65, 66], but this occurred sparingly in neonates [59, 67] and more often in low birthweight populations [68]. The data obtained in this study show that HOMA-IR values are lower than those found in low birthweight neonates [68] suggesting less insulin resistance. In addition, QUICKI was much lower and HOMA-IR much higher than those found in youths suffering or not suffering from obesity and/or metabolic syndrome [66].

#### **12.1. Anthropometric and insulin sensitivity/resistance markers in neonates classified according to insulin values at birth**

Non-significant differences were found between anthropometric characteristics of neonates belonging to both insulin levels (**Table 4**).


Data are means ± standard deviations; BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor-1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR,: homeostatic model assessment-insulin resistance; P, percentile; NS, not significant; ND, not determined.

**Table 5.** Characteristics of the studied population according to cortisol concentrations.

Of the 178 neonates studied, 58 (30 females and 28 males) were hyperinsulinaemic (insulin concentrations >P75). From these 58 hyperinsulinaemic neonates, 86% showed HOMA-IR values ≥P75 taking in account the reference values for neonatal population [63]. As indicated by Gesteiro et al. [67], the increased neonatal insulinaemia was not able to normalize neonatal glycaemia in the >P75 neonates as those newborns presented significantly higher cord-blood insulin levels. Despite the fact that all studied infants were full-term normoweights, about onethird show very high insulin levels (≥15 μIU/mL). No clear reasons are available; however, foetal insulin levels increase under hyperglycaemia and GD [69]. Furthermore, of the 58 hyperinsulinaemic neonates, 25 (43%) were born from mothers presenting IGT and 28 (48%) from mothers without IGT. Thus, neonatal insulin sensitivity/resistance markers could be clearly affected by maternal IGT. This factor effect will be discussed later in this review.

studied in adults [65, 66], but this occurred sparingly in neonates [59, 67] and more often in low birthweight populations [68]. The data obtained in this study show that HOMA-IR values are lower than those found in low birthweight neonates [68] suggesting less insulin resistance. In addition, QUICKI was much lower and HOMA-IR much higher than those found in youths

**12.1. Anthropometric and insulin sensitivity/resistance markers in neonates classified**

**Cortisol <P75 (N = 137)**

Age (years) 30.6 ± 5.24 30.10 ± 5.18 NS Glucose (mg/dL) 83.74 ± 6.85 82.78 ± 6.12 NS

Gestational age (weeks) 39.4 ± 1.16 39.80 ± 1.12 0.067 Birthweight (g) 3338 ± 287 3358 ± 312 NS Length (cm) 50.07 ± 1.37 50.28 ± 1.13 NS

Cephalic perimeter (cm) 34.36 ± 1.15 34.31 ± 1.45 NS Thoracic perimeter (cm) 33.75 ± 1.25 33.79 ± 1.55 NS Apgar 1 8.99 ± 0.76 8.98 ± 0.76 NS Apgar 2 9.94 ± 0.32 9.93 ± 0.26 NS Glucose (mg/dL) 75.33 ± 36.69 88.66 ± 44.63 0.087 Insulin (μIU/mL) 6.39 ± 8.49 7.62 ± 9.38 NS Cortisol (μg/dL) 6.04 ± 1.67 12.74 ± 3.33 ND GH (ng/mL) 16.92 ± 10.26 11.43 ± 8.41 0.001 IGF-1 (ng/mL) 58.27 ± 24.32 58.24 ± 32.73 NS QUICKI 0.44 ± 0.11 0.43 ± 0.15 NS HOMA-IR 1.55 ± 2.87 1.89 ± 3.01 NS Glucose/insulin 25.46 ± 26.58 36.49 ± 42.63 NS Insulin/cortisol 1.16 ± 1.58 0.65 ± 0.91 0.011

) 13.31 ± 1.04 13.27 ± 0.97 NS

Data are means ± standard deviations; BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor-1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR,: homeostatic model assessment-insulin

resistance; P, percentile; NS, not significant; ND, not determined.

**Table 5.** Characteristics of the studied population according to cortisol concentrations.

) 26.62 ± 2.36 26.40 ± 1.93 NS

Non-significant differences were found between anthropometric characteristics of neonates

**Cortisol ≥P75 (N = 41)**

**Significance**

suffering or not suffering from obesity and/or metabolic syndrome [66].

82 Umbilical Cord Blood Banking for Clinical Application and Regenerative Medicine

**according to insulin values at birth**

*Mothers*

*Neonates*

BMI (kg/m2

Ponderal index (kg/m3

belonging to both insulin levels (**Table 4**).

#### **12.2. Anthropometric and insulin sensitivity/resistance markers in neonates classified according to cortisol values at birth**

**Table 5** shows the characteristics of the studied population according to their cortisol levels. In the case of cortisol, from the 178 neonates studied, 20 females and 21 males were hypercortisolaemics as presented cortisol levels ≥ P75.

**Figure 5.** Potential mechanisms implicated in glucocorticoid hormone regulation. Three possibilities are suggested. Note that glucocorticoid sensitivity in the HPA axis and tissues can be independently regulated and the former determines the serum free cortisol levels. Combination of their directions influences net peripheral action of this hormone. The glucocorticoid resistance would be a consequence of glucocorticoid receptors saturation. Modified from Chrousos and Kino [32].

There is a lot of available information about foetal programming and glucocorticoids in low birthweight newborns [16, 17]. However, the present study was done in control neonates where scarce information is available. Cortisol levels at birth were not affected by foetal distress as all of them had a high score in the Apgar test (>7 at the first minute and >9 at the fifth minute). Cortisol levels are highly dependent on stress and type of delivery [70, 71]. As our neonates were strictly selected, other factors, such as low cortisol sensitivity which is different from these factors, should be considered. **Figure 5** shows a model comparison where cortisol and other hormone levels appear clearly related to cortisol resistance. Thus, it can be accepted that high cortisol level at birth would be also associated with low response control of cortisol.

We also find that neonates presenting high cortisolaemia had lower GH (P = 0.001) and an insulin/cortisol ratio (P < 0.05) than those neonates with low–normal cortisol levels.

#### **12.3. Anthropometric and insulin sensitivity/resistance markers in neonates presenting high cortisol and high insulin levels at birth**

This study finds for the first time in the bibliography that the conjunction of high levels of insulin and cortisol together was present in nearly 9% of term, normoweight without foetaldistress neonates, and was associated with low GH concentrations, impaired neonatal insulin sensitivity and high glycaemia at birth.

**Table 6** resumes the anthropometric, hormonal and insulin resistance/sensitivity in neonates attending to their insulin and cortisol levels together. It can be observed that neonates presenting both high insulin and cortisol concentrations showed a slightly higher birthweight without differences in length, body mass index (BMI), ponderal index, cephalic or thoracic perimeters. Although fat was not analysed in these neonates, it can be speculated that as variation in length was lower than in weight, neonates presenting higher levels of both cortisol and insulin tended to accumulate more fat, as it is known that in adults, the troncular fat accumulation is associated with plasma lipids increase [72] and insulin resistance severity in adults [72, 73]. Nonetheless, data in adolescents are controversial and limited [74].

Values of GH (ANOVA, P = 0.009), glucose, insulin, cortisol, QUICKI, HOMA-IR and the glucose/insulin and insulin/cortisol ratios (all P < 0.001) were significantly different between the four groups. When insulin was elevated regardless of cortisol levels, neonates showed higher glucose, IGF-1, HOMA-IR and insulin/cortisol index, but lower QUICKI and glucose/ insulin ratio (at least P < 0.05). Neonates with hypercortisolaemia but not hyperinsulinaemia showed lower values of GH (at least P < 0.05) than those with non-elevated levels of both hormones.

In agreement with our results, where higher IGF-1 correspond to higher birthweight, other groups have found that IGF-1 levels are related to higher birthweight, supporting the premise that IGF-1 plays a major role in promoting the foetal growth [75], but also in keeping the hormonal balance.

Hypercortisolaemia and Hyperinsulinaemia Interaction and Their Impact upon Insulin Resistance/Sensitivity... http://dx.doi.org/10.5772/64946 85

There is a lot of available information about foetal programming and glucocorticoids in low birthweight newborns [16, 17]. However, the present study was done in control neonates where scarce information is available. Cortisol levels at birth were not affected by foetal distress as all of them had a high score in the Apgar test (>7 at the first minute and >9 at the fifth minute). Cortisol levels are highly dependent on stress and type of delivery [70, 71]. As our neonates were strictly selected, other factors, such as low cortisol sensitivity which is different from these factors, should be considered. **Figure 5** shows a model comparison where cortisol and other hormone levels appear clearly related to cortisol resistance. Thus, it can be accepted that high cortisol level at birth would be also associated with low response control

We also find that neonates presenting high cortisolaemia had lower GH (P = 0.001) and an

**12.3. Anthropometric and insulin sensitivity/resistance markers in neonates presenting**

This study finds for the first time in the bibliography that the conjunction of high levels of insulin and cortisol together was present in nearly 9% of term, normoweight without foetaldistress neonates, and was associated with low GH concentrations, impaired neonatal insulin

**Table 6** resumes the anthropometric, hormonal and insulin resistance/sensitivity in neonates attending to their insulin and cortisol levels together. It can be observed that neonates presenting both high insulin and cortisol concentrations showed a slightly higher birthweight without differences in length, body mass index (BMI), ponderal index, cephalic or thoracic perimeters. Although fat was not analysed in these neonates, it can be speculated that as variation in length was lower than in weight, neonates presenting higher levels of both cortisol and insulin tended to accumulate more fat, as it is known that in adults, the troncular fat accumulation is associated with plasma lipids increase [72] and insulin resistance severity in

Values of GH (ANOVA, P = 0.009), glucose, insulin, cortisol, QUICKI, HOMA-IR and the glucose/insulin and insulin/cortisol ratios (all P < 0.001) were significantly different between the four groups. When insulin was elevated regardless of cortisol levels, neonates showed higher glucose, IGF-1, HOMA-IR and insulin/cortisol index, but lower QUICKI and glucose/ insulin ratio (at least P < 0.05). Neonates with hypercortisolaemia but not hyperinsulinaemia showed lower values of GH (at least P < 0.05) than those with non-elevated levels of both

In agreement with our results, where higher IGF-1 correspond to higher birthweight, other groups have found that IGF-1 levels are related to higher birthweight, supporting the premise that IGF-1 plays a major role in promoting the foetal growth [75], but also in keeping the

adults [72, 73]. Nonetheless, data in adolescents are controversial and limited [74].

insulin/cortisol ratio (P < 0.05) than those neonates with low–normal cortisol levels.

**high cortisol and high insulin levels at birth**

84 Umbilical Cord Blood Banking for Clinical Application and Regenerative Medicine

sensitivity and high glycaemia at birth.

of cortisol.

hormones.

hormonal balance.


Data are means ± standard deviations; Different letters for the same parameter are significantly different. BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor-1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR, homeostatic model assessment-insulin resistance.

**Table 6.** Comparison of the different groups of neonates according to their insulin and cortisol levels.

Pancreatic β-cells are very sensitive to substrate and hormone changes during the foetal stage. An inadequate environment *intra utero* would affect the expression of transcription factors and these in turn, the correct β-cell development [1, 7]. Álvarez Escolá and Escrivá Pons [7] observed that impaired intrauterine development due to maternal malnutrition, uterus-placental restriction or GD is related to low IGF-1 concentrations in term rat foetuses. Corticosteriods diminish IGF-2, IGF-1 receptor and transcription factors necessary for β-cell expression at the foetal stage [7, 76]. Although it seems that insulin and cortisol have opposite effects on IGF-1 levels, when hypercortisolaemia and hyperinsulinaemia occurred together, IGF-1 levels were not lower than those of neonates presenting only high insulin levels. Hypercortisolaemia has been related to insulin resistance in adults [17] and low levels of GH in girls aged 3–18 years in increased insulin resistance and hypercortisolaemia situations [77, 78]. Neonates showing high concentrations of insulin and cortisol together showed the lowest concentration of GH and the highest of IGF-1. Although the precise mechanism is unknown, it can be speculated that the inverse relationship between GH and IGF-1 involved in insulin sensitivity [79] could be modulated by cortisol levels. In such a way, high cortisolaemia in neonates with previous impaired insulin sensitivity would tend to reduce GH and increase IGF-1 concentrations. In fact, the mean values of IGF-1 rise up over P75 and GH ones fall under P25 found in the reference population [59]. Thus, paradoxically, the hypercortisolaemia seems to diminish, at least partially, the negative effects ascribed to the hyperinsulinaemia. Circulating IGF-1 plays an important role in maintaining the hormonal balance between GH and insulin and controlling glucose homeostasis. GH antagonizes the action of insulin in liver and peripheral tissues and leads to insulin insensitivity (**Figure 6**).

**Figure 6.** Regulation of insulin secretion by IGF-1 and GH. Notice the inverse relationship between IGF-1 and GH. IGF-1, insulin-like growth factor-1; GH, growth hormone. Modified from Yakar et al. [79].

Neonates presenting hyperinsulinaemia together with hypercortisolaemeia showed low insulin sensitivity and high insuline resistance according to their QUICKY and HOMA-IR values, while neonates with no elevation of both hormones showed QUICKI and HOMA-IR values >P50 and <P50 of the reference population, respectively [59]. Nevertheless, the conjunction of high levels of both hormones does not significantly affect QUICKI and HOMA-IR values with respect to those shown by the neonates presenting only high insulin concentrations. The ROC curve (**Figure 7**) shows that the conjunction of both high insulin and cortisol is a strong predictor for neonates presenting high HOMA-IR and low QUICKI values.

Hypercortisolaemia and Hyperinsulinaemia Interaction and Their Impact upon Insulin Resistance/Sensitivity... http://dx.doi.org/10.5772/64946 87

in increased insulin resistance and hypercortisolaemia situations [77, 78]. Neonates showing high concentrations of insulin and cortisol together showed the lowest concentration of GH and the highest of IGF-1. Although the precise mechanism is unknown, it can be speculated that the inverse relationship between GH and IGF-1 involved in insulin sensitivity [79] could be modulated by cortisol levels. In such a way, high cortisolaemia in neonates with previous impaired insulin sensitivity would tend to reduce GH and increase IGF-1 concentrations. In fact, the mean values of IGF-1 rise up over P75 and GH ones fall under P25 found in the reference population [59]. Thus, paradoxically, the hypercortisolaemia seems to diminish, at least partially, the negative effects ascribed to the hyperinsulinaemia. Circulating IGF-1 plays an important role in maintaining the hormonal balance between GH and insulin and controlling glucose homeostasis. GH antagonizes the action of insulin in liver and peripheral tissues

**Figure 6.** Regulation of insulin secretion by IGF-1 and GH. Notice the inverse relationship between IGF-1 and GH.

Neonates presenting hyperinsulinaemia together with hypercortisolaemeia showed low insulin sensitivity and high insuline resistance according to their QUICKY and HOMA-IR values, while neonates with no elevation of both hormones showed QUICKI and HOMA-IR values >P50 and <P50 of the reference population, respectively [59]. Nevertheless, the conjunction of high levels of both hormones does not significantly affect QUICKI and HOMA-IR values with respect to those shown by the neonates presenting only high insulin concentrations. The ROC curve (**Figure 7**) shows that the conjunction of both high insulin and cortisol is a strong predictor for neonates presenting high HOMA-IR and low QUICKI values.

IGF-1, insulin-like growth factor-1; GH, growth hormone. Modified from Yakar et al. [79].

and leads to insulin insensitivity (**Figure 6**).

86 Umbilical Cord Blood Banking for Clinical Application and Regenerative Medicine

**Figure 7.** ROC curves. Predictive value of both high insulin and cortisol concentrations. GH, growth hormone; QUICKI, quantitative insulin sensitivity check index; HOMA-IR, homeostatic model assessment-insulin resistance; IGF-1, insulin-like growth factor-1. Area under curve: GH = 0.207, QUICKI = 0.205, HOMA-IR = 0.882 (all P < 0.001).

#### **12.4. The effect of maternal impaired glucose tolerance on anthropometric and insulin sensitivity/resistance markers in neonates presenting high cortisol and high insulin levels at birth**

**Table 7** shows neonatal results after considering two factors: the association of high cortisolhigh insulin levels and the presence of IGT during pregnancy. The gestational age did not differ in neonates with high cortisol-high insulin levels whose mother presented or not IGT with respect to those described in a neonatal control population [59].

Neonatal weight and length were significantly affected (P = 0.006 and 0.016, respectively) by the joint effect of high cortisol–high insulin levels but not by IGT. BMI, ponderal index, cephalic and thoracic perimeters, and the Apgar at 1 and 5 min did not change by any of the two studied factors or by their interaction. The maternal glycaemia appeared higher in IGT mothers (P < 0.001) (**Table 7**).

Neonatal cortisolaemia and insulinaemia were significantly affected by maternal IGT and by the interaction of IGT and high cortisol-high insulin levels (all P < 0.001). Neonatal glycaemia increased while GH decreased in children with high insulin–cortisol at birth (P < 0001), but was not affected by IGT presence. IGF-1 was affected by the cortisol–insulin joint (P = 0.031) and by IGT (P = 0.037). The insulin/cortisol ratio was significantly modified by the joint effect of high cortisol–high insulin (P < 0.001), maternal IGT (P = 0.012), as well as the interaction of the two factors (P < 0.001) (**Table 7**).


Data are means ± standard deviations; BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor-1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR, homeostatic model assessment-insulin resistance.

**Table 7.** Effects of high insulin and cortisol levels in neonates and impaired glucose tolerance (IGT) in mothers on anthropometric, foetal distress and insulin sensitivity/resistance markers.

With respect to insulin resistance/sensitivity markers, the glucose/insulin ratio and the QUICKI were not affected by IGT but appeared lower in neonates with high cortisol-high insulin levels (P = 0.032 and <0.001, respectively). HOMA-IR was higher in neonates with high cortisol-high insulin (P < 0.001) and affected by maternal IGT (P = 0.003) and by the interaction of two factors (P = 0.002).

With respect to maternal IGT prevalence, we found that one of two mothers of hyperinsulinaemic children suffered from IGT, while one out of four mothers showed IGT in those groups with insulin below P75. According to Herrera and Ramos Álvarez [19] during the last third of gestation, maternal levels of hPL, oestrogens and progesterone, increase in parallel to the placental mass. These hormones show anti-insulinaemic action, which together with the placenta availability to degrade insulin increases the maternal insulin needs. In fact, during late gestation an increase in the pancreatic β-cell sensibility to the insulintropic stimuli, and also an accelerated insulin turnover have been described. Maternal insulin level effects were partially arrested by insulin resistance. The increased insulinaemia capacitates the future mother to efficiently balance the intense metabolite extraction by the foetus–placenta unity, despite the tendency of insulin resistance occurring in the mother [2, 19].

and by IGT (P = 0.037). The insulin/cortisol ratio was significantly modified by the joint effect of high cortisol–high insulin (P < 0.001), maternal IGT (P = 0.012), as well as the interaction of

> **No IGT (N = 9)**

Age (years) 29.86 ± 4.95 32.22 ± 5.09 28.44 ± 3.09 30.33 ± 5.24 0.76 0.160 0.54 Glucose (mg/dL) 81.97 ± 6.04 86.84 ± 7.03 80.22 ± 4.44 88.83 ± 5.56 0.28 <0.001 0.80

Gestational age (weeks) 39.49 ± 1.14 39.24 ± 1.30 40.11 ± 0.60 40.00 ± 0.00 0.93 0.66 0.17 Birthweight (g) 3336 ± 286 3297 ± 272 3432 ± 402 3488 ± 329 0.26 0.88 0.006 Length (cm) 50.16 ± 1.37 49.82 ± 1.29 50.39 ± 0.99 50.83 ± 1.72 0.17 0.86 0.016

Cephalic perimeter (cm) 34.30 ± 1.35 34.44 ± 1.13 34.42 ± 1.28 34.20 ± 1.15 0.39 0.51 0.51 Thoracic perimeter(cm) 33.75 ± 1.36 33.85 ± 1.25 34.00 ± 1.90 33.40 ± 0.89 0.78 0.33 0.77 Apgar1 8.84 ± 0.89 9.22 ± 0.42 8.78 ± 1.09 9.33 ± 0.52 0.76 0.082 0.93 Apgar2 9.90 ± 0.40 10.0 ± 0.0 9.89 ± 0.33 10.0 ± 0.0 0.99 0.29 0.99 Glucose (mg/dL) 73.92 ± 37.33 79.98 ± 37.77 100.89 ± 48.60 78.33 ± 18.01 0.20 0.065 <0.001 Insulin (μIU/mL) 4.62 ± 5.81 8.96 ± 11.82 18.03 ± 13.95 11.32 ± 4.19 0.012 0.029 <0.001 Cortisol (μg/dL) 7.03 ± 2.89 7.22 ± 3.49 10.35 ± 0.41 16.35 ± 4.62 <0.001 <0.001 <0.001 GH (ng/mL) 17.09 ± 9.40 14.89 ± 12.32 8.44 ± 6.81 8.20 ± 5.04 0.82 0.78 0.020 IGF-1 (ng/mL) 55.87 ± 23.49 58.76 ± 23.32 55.06 ± 16.31 88.58 ± 72.03 0.14 0.037 0.031 QUICKI 0.46 ± 0.14 0.40 ± 0.09 0.35 ± 0.07 0.36 ± 0.06 0.52 0.73 0.001 HOMA-IR 1.12 ± 2.44 2.17 ± 3.42 5.00 ± 5.08 2.10 ± 0.68 0.002 0.003 <0.001 Glucose/insulin 35.80 ± 42.38 18.39 ± 14.29 7.97 ± 4.81 7.93 ± 3.86 0.58 0.54 0.032 Insulin/cortisol 0.80 ± 1.19 1.57 ± 2.11 1.75 ± 1.37 0.76 ± 0.46 0.001 0.012 <0.001 Data are means ± standard deviations; BMI, body mass index; GH, growth hormone; IGF-1, insulin-like growth factor-1; QUICKI, quantitative insulin sensitivity check index; HOMA-IR, homeostatic model assessment-insulin

**Table 7.** Effects of high insulin and cortisol levels in neonates and impaired glucose tolerance (IGT) in mothers on

With respect to insulin resistance/sensitivity markers, the glucose/insulin ratio and the QUICKI were not affected by IGT but appeared lower in neonates with high cortisol-high insulin levels (P = 0.032 and <0.001, respectively). HOMA-IR was higher in neonates with high cortisol-high insulin (P < 0.001) and affected by maternal IGT (P = 0.003) and by the interaction of two factors

anthropometric, foetal distress and insulin sensitivity/resistance markers.

) 13.26 ± 1.02 13.29 ± 1.05 13.49 ± 1.26 13.47 ± 0.66 0.70 0.99 0.14

) 26.47 ± 2.30 26.70 ± 2.40 26.77 ± 2.32 26.52 ± 1.35 0.98 0.97 0.54

**Insulin and cortisol <P75 Insulin and cortisol ≥P75 Two-way ANOVA (significance)**

**IGT (N = 6)** **Interaction IGT High insulin–**

**high cortisol**

the two factors (P < 0.001) (**Table 7**).

*Mothers*

*Neonates*

BMI (kg/m2

resistance.

(P = 0.002).

Ponderal index (kg/m3

**No IGT (N = 96)** **IGT (N = 45)**

88 Umbilical Cord Blood Banking for Clinical Application and Regenerative Medicine

GD is responsible for very high glycaemia that can induce important alterations in foetus size, glucose and insulin production [1, 9]. These premises encouraged us to study whether maternal pregnancy IGT presence could affect the values of insulin resistance (HOMA-IR) or insulin sensitivity (QUICKI) markers in neonates already showing high insulin and high cortisol levels at birth.

Results suggest that neonatal insulin-cortisol levels influence the anthropometric parameters and the insulin resistance/sensitivity markers more than IGT presence. Nonetheless, the effect of IGT on insulin was different in the two study groups, as the level of this hormone decreased remarkably in neonates with high cortisol-high insulin levels. It can be hypothesized that mothers presenting IGT should have high glucose concentrations. This increase would induce, in turn, a neonatal insulin increase in order to avoid the negative effects of glucose excess [1, 9].

It seems interesting to notice that neonates presenting high cortisol-high insulin at birth, whose mothers were presenting IGT showed higher weight and length but the lowest GH and the highest IGF-1 values. Again, the inverse relationship between IGF-1 and GH seems a palliative mechanism against insulin resistance, a highly negative fact for the foetus physiology. Thus, in addition to its role in foetal growth [75], IGF-1 seems crucial in keeping hormonal balance [79]. It also seems relevant that the presence of maternal IGT and high insulin–high cortisol levels at birth reduced the negative effects on glucose, insulin and HOMA-IR but increased cortisol and IGF-1 levels with respect to their non-IGT but high insulin–high cortisol level counterparts. These findings seem paradoxical, as they suggest that the increased maternal glycaemic response to carbohydrate intake would allow the mitigation of the negative effects of reduced GH and increased cortisol levels in the neonates. More studies are needed to understand this interesting metabolic maternal-neonatal interaction.
