**5. Extracellular vesicles as clinical biomarkers, therapeutic targets, and biomedical tools in diabetic cardiovascular diseases**

#### **5.1 Extracellular vesicles as clinical biomarkers**

Early recognition of prediabetes and diabetes is critical for the prevention or the successful treatment of diabetes-induced cardiovascular complications.

The traditional markers used in clinical practice, such as glycated hemoglobin and glucose determinations, are detected only when diabetes is already established and cannot precisely predict an individual's risk of developing diabetes [75].

Biomarkers for early detection of the disease and identification of individuals at risk of developing complications would greatly improve the care of diabetic patients.

The study of EVs is opening new horizons for their potential application not only as therapeutic tools but also as clinical biomarkers for monitoring disease progression. Even if most clinical data are derived from the studies of tumor patients, increased levels of EVs have been detected in body fluids in a variety of cardiovascular and inflammatory pathologies, obesity, atherosclerosis, diabetes,

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*Part One: Extracellular Vesicles as Valuable Players in Diabetic Cardiovascular Diseases*

diagnosis, progression/severity, and management of diabetes.

presented as active players in vascular complications in diabetes.

link between the risk of DN and CVD progression.

in diabetic kidney complications [87, 88].

SERPINA1 and SERPINA3, are present [90].

More than that, since urinary EVs (UEVs) have been described in diabetic nephropathy (DN), they immediately became to be proposed and a biomarker in kidney complication [85, 86]. Patients with DN have exceptionally high rates of cardiovascular morbidity and mortality; thus, there is an emerging need to find the

Owing that urine is an easily accessible fluid sample, UEVs can be obtained in bulk, which make them emerging as a valuable source for disease stage-specific molecular signatures potentially useful in diagnostics. Therefore, UEVs has been proposed to be a novel biomarker in diagnostics, prognosis, and disease progression

Similar to CVDs, in DN, the profile and concentration of proteases and proteases inhibitors is changing in UEVs. For example, Musante et al. [89] have found that cathepsins (A, C, D, L, and XZP) are significantly increased in UEVs isolated from DN patients. Cathepsins are included to the class of lysosomal proteases and their proteolytic activity is related to ECM remodeling [90]. The proteomic study confirmed that in diabetic UEVs, serine proteases and their inhibitors, including

Besides protein cargo, also miRNA UEVs content have some specific features, strongly related to CVD pathomechanism. Barutta et al. showed a differential expression of 22 exosomal miRNAs between micro- and normoalbuminuric

patients with DN [91]. Among them, miR-130a has been found to play a critical role in cardiac fibrosis by directly targeting peroxisome proliferator-activated receptor-γ (PPAR-γ) [91]. Interestingly, miR-155 was significantly reduced in UEVs from DN patients. This miR is significantly expressed and secreted in Krüppel-like factor 5

and metabolic syndrome—biomarkers of both incidence and progression diabetic

Owing to their association with the onset, progression, and pathogenesis of type 2 diabetes, EVs are emerging as a new and attractive class of biomarkers for prognosis,

EVs are detectable in most of the body fluids, including blood, and their expression pattern appears to provide valuable information about the functional state of

In the study by Sun et al. [77], levels of urinary CD63-positive exosomes were found increased at the early stage of renal injury in diabetic nephropathic subjects. On the other hand, circulating MPs, in particular platelet-derived microparticles (PMPs) and EMPs, have been found elevated in a wide range of thrombotic disorders, with an interesting relationship between their levels and disease pathophysiology, activity, or progression [78, 79]. EMP plasma levels have been associated with several CVDs and risk factors. Circulating PMPs are also shown to be involved in the progressive formation of atherosclerotic plaque and development of arterial thrombosis [80, 81], especially in diabetic patients [59]. Indeed, diabetes is characterized by an increased procoagulant state and by a hyperreactive platelet phenotype, with enhanced adhesion, aggregation, and activation. Elevated MP levels, such as TF-positive MPs, have been shown to be one of the procoagulant determinants in patients with type 2 diabetes mellitus [82]. Also, it was demonstrated that EVs participate in the transport of cytokines and angiogenic factors in diabetic patients with ocular complications [83]. Moreover, a recent study showed that distribution of pro- and anti-angiogenic miRNAs in patients with type 2 diabetes is in close touch with the upregulation or downregulation of miRNAs in the plasma fraction enriched in ectosomes (MVs or MPs) [84]. This topic has been widely discussed in a paper by Alexandru et al. [84], in which MPs and MPs-associated miRNAs were

*DOI: http://dx.doi.org/10.5772/intechopen.85225*

retinopathy in diabetic patients.

their parental cells [76].

#### *Part One: Extracellular Vesicles as Valuable Players in Diabetic Cardiovascular Diseases DOI: http://dx.doi.org/10.5772/intechopen.85225*

and metabolic syndrome—biomarkers of both incidence and progression diabetic retinopathy in diabetic patients.

Owing to their association with the onset, progression, and pathogenesis of type 2 diabetes, EVs are emerging as a new and attractive class of biomarkers for prognosis, diagnosis, progression/severity, and management of diabetes.

EVs are detectable in most of the body fluids, including blood, and their expression pattern appears to provide valuable information about the functional state of their parental cells [76].

In the study by Sun et al. [77], levels of urinary CD63-positive exosomes were found increased at the early stage of renal injury in diabetic nephropathic subjects.

On the other hand, circulating MPs, in particular platelet-derived microparticles (PMPs) and EMPs, have been found elevated in a wide range of thrombotic disorders, with an interesting relationship between their levels and disease pathophysiology, activity, or progression [78, 79]. EMP plasma levels have been associated with several CVDs and risk factors. Circulating PMPs are also shown to be involved in the progressive formation of atherosclerotic plaque and development of arterial thrombosis [80, 81], especially in diabetic patients [59]. Indeed, diabetes is characterized by an increased procoagulant state and by a hyperreactive platelet phenotype, with enhanced adhesion, aggregation, and activation. Elevated MP levels, such as TF-positive MPs, have been shown to be one of the procoagulant determinants in patients with type 2 diabetes mellitus [82]. Also, it was demonstrated that EVs participate in the transport of cytokines and angiogenic factors in diabetic patients with ocular complications [83]. Moreover, a recent study showed that distribution of pro- and anti-angiogenic miRNAs in patients with type 2 diabetes is in close touch with the upregulation or downregulation of miRNAs in the plasma fraction enriched in ectosomes (MVs or MPs) [84]. This topic has been widely discussed in a paper by Alexandru et al. [84], in which MPs and MPs-associated miRNAs were presented as active players in vascular complications in diabetes.

More than that, since urinary EVs (UEVs) have been described in diabetic nephropathy (DN), they immediately became to be proposed and a biomarker in kidney complication [85, 86]. Patients with DN have exceptionally high rates of cardiovascular morbidity and mortality; thus, there is an emerging need to find the link between the risk of DN and CVD progression.

Owing that urine is an easily accessible fluid sample, UEVs can be obtained in bulk, which make them emerging as a valuable source for disease stage-specific molecular signatures potentially useful in diagnostics. Therefore, UEVs has been proposed to be a novel biomarker in diagnostics, prognosis, and disease progression in diabetic kidney complications [87, 88].

Similar to CVDs, in DN, the profile and concentration of proteases and proteases inhibitors is changing in UEVs. For example, Musante et al. [89] have found that cathepsins (A, C, D, L, and XZP) are significantly increased in UEVs isolated from DN patients. Cathepsins are included to the class of lysosomal proteases and their proteolytic activity is related to ECM remodeling [90]. The proteomic study confirmed that in diabetic UEVs, serine proteases and their inhibitors, including SERPINA1 and SERPINA3, are present [90].

Besides protein cargo, also miRNA UEVs content have some specific features, strongly related to CVD pathomechanism. Barutta et al. showed a differential expression of 22 exosomal miRNAs between micro- and normoalbuminuric patients with DN [91]. Among them, miR-130a has been found to play a critical role in cardiac fibrosis by directly targeting peroxisome proliferator-activated receptor-γ (PPAR-γ) [91]. Interestingly, miR-155 was significantly reduced in UEVs from DN patients. This miR is significantly expressed and secreted in Krüppel-like factor 5

*Extracellular Vesicles and Their Importance in Human Health*

ence glucose homeostasis and insulin resistance [68].

of cells from which the EVs are released.

**5.1 Extracellular vesicles as clinical biomarkers**

tissue cells into circulation are enclosed in vesicles. EVs derived from adipose tissue may play a role in the paracrine cross talk between adipocytes and macrophages in adipose tissue in obesity [51], and in endocrine manner for transmission of signals to other cells from cardiovascular system [67]. There are the studies that support the idea that EVs are important mediators for metabolic organ cross talk. Thus, it was hypothesized that insulin-secreting beta (β) cells and insulin-sensitive tissues release exosomes that can be transferred to other metabolic organs, or to immune or endothelial cells. In this way, in an autocrine or paracrine manner, exosomes influ-

When circulating miRNA profile of lean and obese individuals was compared, those miRNAs differentially expressed were predicted to regulate inflammatory and fibrotic signaling pathways [69]. Moreover, in obesity, exosomes from adipose tissue-derived MSCs have reduced pro-angiogenic properties due to decreased content in miR-126, VEGF, and MMP-2. A differential EV proteomic profile has also been observed between obese diabetic and obese nondiabetic rats [70]. In a recent study, the lean mice treated with exosomes from obese mice developed glucose intolerance and insulin resistance. In addition, using exosomes transfected with a specific siRNA targeting PPARα, the phenotype induced by obesity-associated miR-NAs was recapitulated. Importantly, it was demonstrated that obesity-associated

In type 1 diabetes, the imbalances between effector T cells and regulatory T cells, as well as dendritic cell presentation of islet auto-antigens, play an important role in the destruction of islet β cells. It has been shown that MVs derived from endothelial progenitor cells (EPCs) combined with islets can activate angiogenesis, decrease leucocyte-endothelial interaction, and improve pancreatic β cell function [72]. Another study revealed that insulinoma-released exosomes or MPs are immunostimulatory and can activate autoreactive T cells spontaneously developed in nonobese diabetic mice [73]. Exosomes could also serve as triggering factors for specific autoimmunity events leading to diabetes, as shown in another study where in NOD mice exosomes released by islet-derived MSCs trigger autoimmune responses [74]. Thus, specific biological roles of EVs are dependent on functional state and the type

**5. Extracellular vesicles as clinical biomarkers, therapeutic targets, and** 

Early recognition of prediabetes and diabetes is critical for the prevention or the

The traditional markers used in clinical practice, such as glycated hemoglobin and glucose determinations, are detected only when diabetes is already established and cannot precisely predict an individual's risk of developing diabetes [75].

Biomarkers for early detection of the disease and identification of individuals at risk of developing complications would greatly improve the care of diabetic

The study of EVs is opening new horizons for their potential application not only as therapeutic tools but also as clinical biomarkers for monitoring disease progression. Even if most clinical data are derived from the studies of tumor patients, increased levels of EVs have been detected in body fluids in a variety of cardiovascular and inflammatory pathologies, obesity, atherosclerosis, diabetes,

**biomedical tools in diabetic cardiovascular diseases**

successful treatment of diabetes-induced cardiovascular complications.

exosomal miRNAs modulate glucose and lipid metabolism in mice [71].

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patients.

(KLF5)-overexpressing VSMCs and it is considered as a potent regulator of endothelium barrier function through regulating endothelial targeting tight junction protein expression. In murine model of atherosclerosis, VSMCs-derived exosomes mediated the transfer of miR-155 from VSMCs to ECs, which led to an increased endothelial permeability and enhanced atherosclerotic progression [92]. These data suggest the possible role of UEVs in kidney remodeling, which can bring the new insight into vascular complications and vascular risk in diabetes.
