Surface markers on microparticles involved in obesity-derived diseases

AIMS

This review aimed to investigate the different types of microparticles playing role in obesity-related diseases. Additionally, the factors participating in changing the microparticles amount in obese people will also be discussed.

MATERIAL & METHODS

The authors collected the relevant articles published until 2023 and these are carefully selected from three scientific databases based on keywords.

KEY FINDINGS

It has been revealed that exercise might change the microparticle content in the body. The other factor which participates in obesity process is the oxidative stress which is increased in microparticles. Moreover, the obesity is implicated in metabolic conditions including diabetes and cardiovascular diseases.

SIGNIFICANCE

More than one-third of people on the planet today are known as overweight individuals. Microparticles (MPs) are small membrane-bound vesicles that are found in healthy people's blood and are elevated in patients with pathological conditions such as obesity. MPs mostly come from platelets, leukocytes, endothelial cells, and vascular smooth muscle cells. Considering the effect of obesity on microparticles, these small membrane-bound vesicles might play a crucial role in preventing or treatment of obesity.

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

Extracellular vesicles (EVs) are nanoparticles released from various cell types that have emerged as powerful new therapeutic option for a variety of diseases. EVs are involved in the transmission of biological signals between cells and in the regulation of a variety of biological processes, highlighting them as potential novel targets/platforms for therapeutics intervention and/or delivery. Therefore, it is necessary to investigate new aspects of EVs' biogenesis, biodistribution, metabolism, and excretion as well as safety/compatibility of both unmodified and engineered EVs upon administration in different pharmaceutical dosage forms and delivery systems. In this review, we summarize the current knowledge of essential physiological and pathological roles of EVs in different organs and organ systems. We provide an overview regarding application of EVs as therapeutic targets, therapeutics, and drug delivery platforms. We also explore various approaches implemented over the years to improve the dosage of specific EV products for different administration routes.

Circulating microparticles as indicators of cardiometabolic risk in PCOS

Polycystic ovary syndrome (PCOS), the most prevalent endocrine disturbance of the female reproductive system, is associated with several pathologic conditions, such as metabolic syndrome, obesity, diabetes, dyslipidemia, and insulin resistance, all of which are tightly connected to its progression. These factors are associated with a type of extracellular vesicle, ie, microparticles (MPs), released by shedding due to cell activation and apoptosis. Circulating MPs (cMPs) are secreted by a variety of cells, such as platelets, endothelial, leukocytes, and erythrocytes, and contain cytoplasmic substances derived from parent cells that account for their biologic activity. Current evidence has clearly shown that increased cMPs contribute to endothelial dysfunction, diabetes, hypertriglyceridemia, metabolic syndrome, cardiovascular abnormalities as well as PCOS. It has also been reported that platelet and endothelial MPs are specifically increased in PCOS thus endangering vascular health and subsequent cardiovascular disease. Given the importance of cMPs in the pathophysiology of PCOS, we review the role of cMPs in PCOS with a special focus on cardiometabolic significance.

Extracellular Vesicles and Their Emerging Roles as Cellular Messengers in Endocrinology: An Endocrine Society Scientific Statement

During the last decade, there has been great interest in elucidating the biological role of extracellular vesicles (EVs), particularly, their hormone-like role in cell-to-cell communication. The field of endocrinology is uniquely placed to provide insight into the functions of EVs, which are secreted from all cells into biological fluids and carry endocrine signals to engage in paracellular and distal interactions. EVs are a heterogeneous population of membrane-bound vesicles of varying size, content, and bioactivity. EVs are specifically packaged with signaling molecules, including lipids, proteins, and nucleic acids, and are released via exocytosis into biofluid compartments. EVs regulate the activity of both proximal and distal target cells, including translational activity, metabolism, growth, and development. As such, EVs signaling represents an integral pathway mediating intercellular communication. Moreover, as the content of EVs is cell-type specific, it is a "fingerprint" of the releasing cell and its metabolic status. Recently, changes in the profile of EV and bioactivity have been described in several endocrine-related conditions including diabetes, obesity, cardiovascular diseases, and cancer. The goal of this statement is to highlight relevant aspects of EV research and their potential role in the field of endocrinology.

Extracellular Vesicles in Atherosclerosis Research

The methodologies described in this chapter inform on how to incorporate extracellular vesicles (EV) in model systems to investigate their role in the initiation and progression of the atherosclerotic plaque. The section will cover application of EV in coagulation and thrombus formation, monocytic migration, and adhesion to endothelial monolayers. These methodologies can be used with EV isolated from any cell type and under any conditions.

In sickness and in health: The functional role of extracellular vesicles in physiology and pathology in vivo: Part II: Pathology: Part II: Pathology

It is clear from Part I of this series that extracellular vesicles (EVs) play a critical role in maintaining the homeostasis of most, if not all, normal physiological systems. However, the majority of our knowledge about EV signalling has come from studying them in disease. Indeed, EVs have consistently been associated with propagating disease pathophysiology. The analysis of EVs in biofluids, obtained in the clinic, has been an essential of the work to improve our understanding of their role in disease. However, to interfere with EV signalling for therapeutic gain, a more fundamental understanding of the mechanisms by which they contribute to pathogenic processes is required. Only by discovering how the EV populations in different biofluids change-size, number, and physicochemical composition-in clinical samples, may we then begin to unravel their functional roles in translational models in vitro and in vivo, which can then feedback to the clinic. In Part II of this review series, the functional role of EVs in pathology and disease will be discussed, with a focus on in vivo evidence and their potential to be used as both biomarkers and points of therapeutic intervention.

Urinary exosomal long noncoding RNAs serve as biomarkers for early detection of non-small cell lung cancer

Objective: Increasing the efficiency of early diagnosis using noninvasive biomarkers is crucial for enhancing the survival rate of lung cancer patients. We explore the differential expression of non-small cell lung cancer (NSCLC)-related long noncoding RNAs (lncRNAs) in urinary exosomes in NSCLC patients and normal controls to diagnose lung cancer.

Methods: A differential expression analysis between NSCLC patients and healthy controls was performed using microarrays. Gene ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to predict potential functions of lncRNAs in NSCLC. quantitative real-time PCR (QT-PCR) was used to verify microarray results.

Results: A total of 640 lncRNAs (70 up- and 570 down-regulated) were differentially expressed in NSCLC patients in comparison to healthy controls. Six lncRNAs were detected by QT-PCR. GO term and KEGG pathway analyses showed that differential lncRNAs were enriched in cellular component organization or biogenesis, as well as other biological processes and signaling pathways, such as the PI3K-AKT, FOXO, p53, and fatty acid biosynthesis.

Conclusions: The differential lncRNAs in urinary exosomes are potential diagnostic biomarkers of NSCLC. The lncRNAs enriched in specific pathways may be associated with tumor cell proliferation, tumor cell apoptosis, and the cell cycle involved in the pathogenesis of NSCLC.

The Emerging Roles and Therapeutic Potential of Extracellular Vesicles in Infertility

Infertility is becoming much more common and affects more couples. The past years witnessed the rapid development of the diagnosis and treatment upon infertility, which give numerous coupled more opportunities become parents. Extracellular vesicles are known as nano-sized membrane vesicles to play a major role in intracellular communication. In recent years, several basic and clinical studies have tried to investigate the correlation between the reproductive health/disorder and extracellular vesicles. However, the mechanism is still unclear. In this review, we reviewed the relationship between reproductive physiology and extracellular vesicles, and then collectively focused on the recent findings on the relationship between extracellular and infertility, and its consequent influence on the novel insight regarding the therapeutic strategies for infertility in the future clinical practice.

Oral contraceptives increase platelet microparticle levels in normal-weight women with polycystic ovary syndrome

PURPOSE

Platelet microparticles (PMPs), which are microvesicles shed from platelets, participate in inflammation, vascular homeostasis, and thrombosis. PMPs are increased in obese women with polycystic ovary syndrome (PCOS). Agents that modulate hormonal aspects of PCOS could affect the levels of PMPs. The aim of the present study was to evaluate the effects of oral contraceptives (OCPs), antiandrogen, and metformin use for 6 and 12 months on PMPs in normal-weight women with PCOS.

METHODS

Forty-five women with PCOS and 13 healthy women were recruited. Biochemical, hormonal, and clinical parameters were recorded. Women with PCOS received treatment with OCPs, OCPs+antiandrogens, or metformin, depending on their main complaint or clinical/biochemical findings. PMPs were measured at baseline and after 6 and 12 months.

RESULTS

At baseline, patients with PCOS had higher levels of PMPs than controls (p = 0.017), which increased after 6-month treatment with OCPs (p = 0.006). Subsequently, they decreased after 12-month treatment (p = 0.046). Metformin had no effect on PMP levels.

CONCLUSION

In conclusion, PMP levels are increased in PCOS and further increase with OCP use. This effect could possibly contribute to the increased risk of venous thromboembolism associated with OCP use. However, further studies are needed to elucidate the exact role of PMPs in PCOS.

Differential expression profile of plasma exosomal microRNAs in women with polycystic ovary syndrome

OBJECTIVE

To examine different expression profiles of plasma exosomal microRNA (miRNA) in polycystic ovary syndrome (PCOS) patients and controls, and their potential roles in PCOS pathogenesis.

DESIGN

Experimental study.

SETTING

Center for reproductive medicine.

PATIENT(S)

Seventy-five PCOS patients and 75 age-matched controls.

INTERVENTION(S)

Plasma exosomes miRNAs sequenced from 15 PCOS patients and 15 controls.

MAIN OUTCOME MEASURE(S)

Plasma exosomal miRNA expression and the correlation between PCOS phenotypes and miRNA expression.

RESULT(S)

The sequenced plasma exosomes miRNAs were further determined by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in a larger cohort, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Correlation analysis and receiver operating characteristic (ROC) curve analysis were used to determine the association between PCOS phenotypes and miRNA expression. The miRNA sequencing revealed 34 exosomal miRNAs were differentially expressed between PCOS patients and controls. Via qRT-PCR, five differentially expressed miRNAs (miR-126-3p, miR-146a-5p, miR-20b-5p, miR-106a-5p, and miR-18a-3p) were identified. The GO and KEGG analyses predicted their target functions included axon guidance, mitogen-activated protein kinase (MAPK) signaling, endocytosis, circadian rhythms, and cancer pathways. The expression of these miRNAs correlated with menstrual cycle, antral follicle count, hormone level, and combined yielded a ROC curve area of 0.781 in discriminating PCOS patients from the controls.

CONCLUSION(S)

Differential expression of plasma exosomal miRNAs may confer a risk of PCOS and may be helpful in distinguishing PCOS patients from controls. Certain miRNA expression may associated to the disease progression, which could help in an epigenetic understanding of the pathophysiology of PCOS.

Extracellular Vesicles: Recent Developments in Aging and Reproductive Diseases

Extracellular vesicles (EVs), present in cell culture media and several body fluids, play a prominent role in intercellular communication under physiological and pathological conditions. We performed a systematic literature search to review evidence regarding the existence, composition, and release of different EVs, as well as the biomarkers, cargos, and separation methods. We also reviewed the potential of EVs to transport cargos and alter the function and phenotype of recipient cells associated with aging and reproductive diseases, including polycystic ovary syndrome and endometriosis. In aging, EVs promote inflammatory reactions and offsetting the occurrence of aging. In the polycystic ovary syndrome and endometriosis, EVs and their cargos are involved in the occurrence of diseases, therapeutic strategies, and perform as non-invasive biomarkers. As the study of EVs is still in the early stages, it is not surprising that most of the current literature only describes their possible roles.

Plasma endothelial microvesicles and their carrying miRNA-155 serve as biomarkers for ischemic stroke

Endothelial microvesicles (EMVs) could reflect the status of endothelial cells (ECs) which are involved in the pathogenesis of ischemic stroke (IS). MiR-155 could regulate EC functions. However, their roles in IS remain unclear. This study aimed to investigate the levels of plasma EMVs and EMVs carrying miRNA-155 (EMVs-miR-155) in IS patients to explore their potential roles as biomarkers. Ninety-three IS patients and 70 controls were recruited in this study. The levels of circulating EMVs and EMVs-miR-155 were detected by fluorescence nanoparticle tracking analysis and quantitative real-time PCR, respectively. The correlations between level of EMVs/EMVs-miR-155 and the onset time, severity, infarct volume, and subtypes of IS were analyzed. The severity and infarct volume were assessed by NIHSS and magnetic resonance imaging, respectively. Multivariate logistic regression analysis was used to investigate the risk factors of IS. The ROC curve and area under ROC curve (AUC) of EMVs and EMVs-miR-155 were determined. The levels of plasma EMVs and EMVs-miR-155 were increased significantly in acute and subacute stages of IS and remained unchanged in chronic stage, and were positively related to the infarct volume and NIHSS scores and were associated with large artery atherosclerosis and cardioembolism subtypes defined by Trial of Org 10 172 in acute stroke treatment (TOAST) classification. Multivariate logistic regression analysis demonstrated that plasma EMVs and EMVs-miR-155 were significant and independent risk factors of IS and their AUC were 0.778 and 0.851, respectively, and increased to 0.892 after combination. Our study suggests that plasma EMVs and EMVs-miR-155 are promising biomarkers for IS. The diagnostic value of EMVs-miR-155 is higher and their combination is the best.

Mesenchymal stromal cell-derived small extracellular vesicles restore lung architecture and improve exercise capacity in a model of neonatal hyperoxia-induced lung injury

Early administration of mesenchymal stromal cell (MSC)-derived small extracellular vesicles (MEx) has shown considerable promise in experimental models of bronchopulmonary dysplasia (BPD). However, the ability of MEx to reverse the long-term pulmonary complications associated with established BPD remains unknown. In this study, MEx were isolated from media conditioned by human Wharton’s Jelly-derived MSC cultures. Newborn mice (FVB strain) were exposed to hyperoxia (HYRX (75% O2)) before returning to room air at postnatal day 14 (PN14). Following prolonged HYRX-exposure, animals received a single MEx dose at PN18 or serial MEx treatments at PN18-39 (“late” intervention). This group was compared to animals that received an early single MEx dose at PN4 (“early” intervention). Animals were harvested at PN28 or 60 for assessment of pulmonary parameters. We found that early and late MEx interventions effectively ameliorated core features of HYRX-induced neonatal lung injury, improving alveolar simplification, pulmonary fibrosis, vascular remodelling and blood vessel loss. Exercise capacity testing and assessment of pulmonary hypertension (PH) showed functional improvements following both early and late MEx interventions. In conclusion, delivery of MEx following prolonged HYRX-exposure improves core features of experimental BPD, restoring lung architecture, decreasing pulmonary fibrosis and vascular muscularization, ameliorating PH and improving exercise capacity. Taken together, delivery of MEx may not only be effective in the immediate neonatal period to prevent the development of BPD but may provide beneficial effects for the management and potentially the reversal of cardiorespiratory complications in infants and children with established BPD.

The Role of Exosomes in Diseases Related to Infertility

Exosomes, small extracellular vesicles with diameters of 40-100nm, are generated through the fusion of multivessel with plasma membrane and secreted by a variety of living cells. Exosomes contain lipid bilayer membrane and releasable functionally active proteins, mRNA and microRNAs (miRNAs). This article reviews the latest progress of researches on exosomes in diseases that lead to infertility.

Hyperandrogenism and Metabolic Syndrome Are Associated With Changes in Serum-Derived microRNAs in Women With Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) remains one of the most common endocrine disorder in premenopausal women with an unfavorable metabolic risk profile. Here, we investigate whether biochemical hyperandrogenism, represented by elevated serum free testosterone, resulted in an aberrant circulating microRNA (miRNAs) expression profile and whether miRNAs can identify those PCOS women with metabolic syndrome (MetS). Accordingly, we measured serum levels of miRNAs as well as biochemical markers related to MetS in a case-control study of 42 PCOS patients and 20 Controls. Patients were diagnosed based on the Rotterdam consensus criteria and stratified based on serum free testosterone levels (≥0.034 nmol/l) into either a normoandrogenic (n = 23) or hyperandrogenic (n = 19) PCOS group. Overall, hyperandrogenic PCOS women were more insulin resistant compared to normoandrogenic PCOS women and had a higher prevalence of MetS. A total of 750 different miRNAs were analyzed using TaqMan Low-Density Arrays. Altered levels of seven miRNAs (miR-485-3p, -1290, -21-3p, -139-3p, -361-5p, -572, and -143-3p) were observed in PCOS patients when compared with healthy Controls. Stratification of PCOS women revealed that 20 miRNAs were differentially expressed between the three groups. Elevated serum free testosterone levels, adjusted for age and BMI, were significantly associated with five miRNAs (miR-1290, -20a-5p, -139-3p, -433-3p, and -361-5p). Using binary logistic regression and receiver operating characteristic curves (ROC), a combination panel of three miRNAs (miR-361-5p, -1225-3p, and -34-3p) could correctly identify all of the MetS cases within the PCOS group. This study is the first to report comprehensive miRNA profiling in different subgroups of PCOS women with respect to MetS and suggests that circulating miRNAs might be useful as diagnostic biomarkers of MetS for a different subset of PCOS.

The CD105:CD106 microparticle ratio is CD106 dominant in polycystic ovary syndrome compared to type 2 diabetes and healthy subjects

BACKGROUND

A retrospective analysis was carried out from patients and controls during the past 5 years from a series of studies investigating endothelial microparticles (MP).

METHODS

In total, 319 samples from 207 individuals were included in this analysis, from patients with type 2 diabetes (T2D, n = 105), women with polycystic ovary syndrome (PCOS, n = 145) and healthy volunteers (n = 69). All data were generated via the same flow cytometry protocol with the same antibody clones. Endothelial markers CD105 (Endoglin) and CD106 (Vascular cell adhesion molecule-1) were used to enumerate MP in venous blood.

RESULTS

The ratio of CD105MP:CD106MP was significantly different between groups (F = 63.43, p < 0.0001). Women with PCOS were found to have a median CD105MP:CD106MP ratio of 0.40 (IQR 0.24-0.57), suggesting approximately two CD106MP were found per CD105MP. The T2D group showed a median ratio of 2.32 (1.51-3.69) whereas in healthy volunteers the ratio was 2.21 (1.63-3.55). Serum intercellular adhesion molecule-1 was also shown to be significantly increased in PCOS when compared with control or T2D groups (F = 14.5, p < 0.001).

CONCLUSION

These data suggest that women with PCOS have an altered endothelial MP release in favour of CD106. Thus a potential activated endothelial state exists in women with PCOS with a shift towards a predominantly CD106MP profile.

Circulating Endothelial Microparticles Reduce in Concentration Following an Exercise Programme in Women With Polycystic Ovary Syndrome

Purpose: Endothelial dysfunction is a known comorbidity in women with polycystic ovary syndrome (PCOS). The aim was to assess if supervised, moderate intensity exercise could potentially impact markers of endothelial disruption; endothelial cell derived microparticles (EMP). Methods: The current study investigated the effects of a supervised 8-week moderate intensity exercise programme on EMP in women with PCOS (n = 11) and control women free from any known disease (n = 10). EMP were enumerated via specific antibody (CD105, CD106) labeling and flow cytometry. Results: CD105+MP significantly reduced in women with PCOS from pre to post-exercise programme, with CD105+ MP reducing from 2114 CD105+ MP per μl platelet free plasma (PFP) to 424 CD105+ MP per μl PFP (p = 0.025). Control women showed no significant change in CD105+ MP (p = 0.25) after completing the same exercise programme. CD106+ MP showed no change in either PCOS (p = 0.95) or control groups (p = 0.99). No significant correlations existed with the changes in EMP compared to body composition changes as a result of exercise. Conclusion: Supervised, moderate intensity exercise independent of substantial weight loss reduced circulating CD105+ MP, likely reflecting an improvement in endothelial function in women with PCOS compared to healthy control women. Additionally, EMP may be a useful marker for physical improvement in exercise programmes for clinical populations.

Extracellular Vesicles in Human Reproduction in Health and Disease

Extensive evidence suggests that the release of membrane-enclosed compartments, more commonly known as extracellular vesicles (EVs), is a potent newly identified mechanism of cell-to-cell communication both in normal physiology and in pathological conditions. This review presents evidence about the formation and release of different EVs, their definitive markers and cargo content in reproductive physiological processes, and their capacity to convey information between cells through the transfer of functional protein and genetic information to alter phenotype and function of recipient cells associated with reproductive biology. In the male reproductive tract, epididymosomes and prostasomes participate in regulating sperm motility activation, capacitation, and acrosome reaction. In the female reproductive tract, follicular fluid, oviduct/tube, and uterine cavity EVs are considered as vehicles to carry information during oocyte maturation, fertilization, and embryo-maternal crosstalk. EVs via their cargo might be also involved in the triggering, maintenance, and progression of reproductive- and obstetric-related pathologies such as endometriosis, polycystic ovarian syndrome, preeclampsia, gestational diabetes, and erectile dysfunction. In this review, we provide current knowledge on the present and future use of EVs not only as biomarkers, but also as therapeutic targeting agents, mainly as vectors for drug or compound delivery into target cells and tissues.

Metformin reduces total microparticles and microparticles-expressing tissue factor in women with polycystic ovary syndrome

PURPOSE

The objective of this study was to evaluate the levels of total microparticles (MPs) and microparticles-expressing tissue factor (TFMPs) in women with polycystic ovarian syndrome (PCOS) who use metformin comparing to those who do not take metformin.

METHODS

We quantified total MPs and TFMPs in the plasma of 50 patients with PCOS-13 of these women used metformin (850 mg 2×/day during at least 6 months) and the other 37 did not. For this purpose, the microparticles (MPs) were purified by differential centrifugation of the plasma and, subsequently, by flow cytometry, using annexin-V and CD142 as markers.

RESULTS

Total MPs levels were lower in treated patients (59.58 ± 28.43 MPs/µL) when compared to untreated group (97.32 ± 59.42; p = 0.033). Plasma levels of TFMPs were also significantly lower in the group of patients who used metformin (1.10 ± 0.94 MPs/µL) when compared to untreated patients (2.20 ± 1.42 MPs/µL) (p = 0.003).

CONCLUSIONS

Considering that metformin reduced the levels of total MPs and TFMPs, our results suggest that this mechanism could be involved in the antithrombotic metformin effect, corroborating with the indication of this drug in the PCOS treatment.

Microparticles: Inflammatory and haemostatic biomarkers in Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is associated with a chronic low-grade inflammation and predisposition to hemostatic and atherosclerotic complications. This case-control study evaluated the microparticles (MPs) profile in patients with the PCOS and related these MPs to clinical and biochemical parameters. MPs derived from platelets (PMPs), leuckocytes (LMPs) and endothelial cells (EMPs) were evaluated, as well as MPs expressing tissue factor (TFMPs), by flow cytometry, comparing women with PCOS (n = 50) and a healthy control group (n = 50). PCOS women presented increased total MPs, PMPs, LMPs and EMPs levels when compared to control group (all p < 0.05). TFMPs was similar between the groups (p = 0.379). In conclusion, these MPs populations could be useful biomarkers for association with thrombosis and cardiovascular disease in PCOS women.

Nitrite-derived nitric oxide reduces hypoxia-inducible factor 1α-mediated extracellular vesicle production by endothelial cells

INTRODUCTION

Extracellular vesicles (EVs) are small, spherical particles enclosed by a phospholipid bilayer (∼30-1000 nm) released from multiple cell types, and have been shown to have pathophysiological roles in a plethora of disease states. The transcription factor hypoxia-inducible factor-1 (HIF-1) allows for adaptation of cellular physiology in hypoxia and may permit the enhanced release of EVs under such conditions. Nitric oxide (NO) plays a pivotal role in vascular homeostasis, and can modulate the cellular response to hypoxia by preventing HIF-1 accumulation. We aimed to selectively target HIF-1 via sodium nitrite (NaNO₂) addition, and examine the effect on endothelial EV, size, concentration and function, and delineate the role of HIF-1 in EV biogenesis.

METHODS

Endothelial (HECV) cells were exposed to hypoxic conditions (1% O₂, 24 h) and compared to endothelial cells exposed to normoxia (21% O₂) with and without the presence of sodium nitrite (NaNO₂) (30 μM). Allopurinol (100 μM), an inhibitor of xanthine oxidoreductase, was added both alone and in combination with NaNO₂ to cells exposed to hypoxia. EV and cell preparations were quantified by nanoparticle tracking analysis and confirmed by electron microscopy. Western blotting and siRNA were used to confirm the role of HIF-1α and HIF-2α in EV biogenesis. Flow cytometry and time-resolved fluorescence were used to assess the surface and intravesicular protein content.

RESULTS

Endothelial (HECV) cells exposed to hypoxia (1% O₂) produced higher levels of EVs compared to cells exposed to normoxia. This increase was confirmed using the hypoxia-mimetic agent desferrioxamine. Treatment of cells with sodium nitrite (NaNO₂) reduced the hypoxic enhancement of EV production. Treatment of cells with the xanthine oxidoreductase inhibitor allopurinol, in addition to NaNO₂ attenuated the NaNO₂-attributed suppression of hypoxia-mediated EV release. Transfection of cells with HIF-1α siRNA, but not HIF-2α siRNA, prior to hypoxic exposure prevented the enhancement of EV release.

CONCLUSION

These data provide evidence that hypoxia enhances the release of EVs in endothelial cells, and that this is mediated by HIF-1α, but not HIF-2α. Furthermore, the reduction of NO₂^- to NO via xanthine oxidoreductase during hypoxia appears to inhibit HIF-1α-mediated EV production.

Role of Platelet-Derived Microvesicles As Crosstalk Mediators in Atherothrombosis and Future Pharmacology Targets: A Link between Inflammation, Atherosclerosis, and Thrombosis

Reports in the last decade have suggested that the role of platelets in atherosclerosis and its thrombotic complications may be mediated, in part, by local secretion of platelet-derived microvesicles (pMVs), small cell blebs released during the platelet activation process. MVs are the most abundant cell-derived microvesicle subtype in the circulation. High concentrations of circulating MVs have been reported in patients with atherosclerosis, acute vascular syndromes, and/or diabetes mellitus, suggesting a potential correlation between the quantity of microvesicles and the clinical severity of the atherosclerotic disease. pMVs are considered to be biomarkers of disease but new information indicates that pMVs are also involved in signaling functions. pMVs evoke or promote haemostatic and inflammatory responses, neovascularization, cell survival, and apoptosis, processes involved in the pathophysiology of cardiovascular disease. This review is focused on the complex cross-talk between platelet-derived microvesicles, inflammatory cells and vascular elements and their relevance in the development of the atherosclerotic disease and its clinical outcomes, providing an updated state-of-the art of pMV involvement in atherothrombosis and pMV potential use as therapeutic agent influencing cardiovascular biomedicine in the future.

The significance of platelet microparticles in patients with chronic hepatitis C and their association with antiviral treatment and smoking

Background

Platelet microparticles (PMPs) are platelet-derived membrane vesicles involved in cardiovascular diseases and atherosclerosis. Chronic hepatitis C (CHC) is associated with increased atherosclerosis, but the effect of therapy on its atherogenic potential has not been adequately studied.

Methods

We evaluated PMP levels before and after treatment with pegylated-interferon-alfa and ribavirin in 28 CHC patients compared with 20 non-alcoholic fatty liver disease (NAFLD) patients and 20 healthy volunteers (HV).

Results

Twenty-four (86%) CHC patients achieved sustained virological response (SVR). PMP levels were determined at baseline in CHC, NAFLD patients, and HV, and at end-of-treatment (EOT) and 24 weeks post-treatment (SVR24) in CHC patients. PMP levels at baseline were higher in CHC than NAFLD patients (P<0.001) and HV (P=0.007). Higher PMPs at baseline were observed in smokers than non-smokers with CHC (P=0.006). Among smokers from all groups, PMPs at baseline were higher in CHC than NAFLD patients (P=0.001) and HV (P=0.024). In CHC patients, PMPs declined from baseline to both EOT (P=0.035) and SVR24 (P=0.006). Only CHC patients with SVR had a significant decline in PMPs from baseline to SVR24 (P=0.018). PMPs at ΕΟΤ and SVR24 in all CHC patients were similar to PMPs in NAFLD patients and HV.

Conclusions

PMP levels are increased in CHC patients, particularly smokers, which further supports the atherosclerotic potential of CHC and suggests a potentially synergistic effect of smoking and CHC on the atherosclerotic process. Since PMP levels in CHC patients with SVR were similar to NAFLD patients and HV, the atherosclerotic potential of CHC seems to be abolished by effective antiviral treatment.

Microvesicles and exosomes: new players in metabolic and cardiovascular disease

The past decade has witnessed an exponential increase in the number of publications referring to extracellular vesicles (EVs). For many years considered to be extracellular debris, EVs are now seen as novel mediators of endocrine signalling via cell-to-cell communication. With the capability of transferring proteins and nucleic acids from one cell to another, they have become an attractive focus of research for different pathological settings and are now regarded as both mediators and biomarkers of disease including cardio-metabolic disease. They also offer therapeutic potential as signalling agents capable of targeting tissues or cells with specific peptides or miRNAs. In this review, we focus on the role that microvesicles (MVs) and exosomes, the two most studied classes of EV, have in diabetes, cardiovascular disease, endothelial dysfunction, coagulopathies, and polycystic ovary syndrome. We also provide an overview of current developments in MV/exosome isolation techniques from plasma and other fluids, comparing different available commercial and non-commercial methods. We describe different techniques for their optical/biochemical characterization and quantitation. We also review the signalling pathways that exosomes and MVs activate in target cells and provide some insight into their use as biomarkers or potential therapeutic agents. In summary, we give an updated focus on the role that these exciting novel nanoparticles offer for the endocrine community.

Characterisation of adipocyte-derived extracellular vesicles released pre- and post-adipogenesis

Extracellular vesicles (EVs) are submicron vesicles released from many cell types, including adipocytes. EVs are implicated in the pathogenesis of obesity-driven cardiovascular disease, although the characteristics of adipocyte-derived EVs are not well described. We sought to define the characteristics of adipocyte-derived EVs before and after adipogenesis, hypothesising that adipogenesis would affect EV structure, molecular composition and function. Using 3T3-L1 cells, EVs were harvested at day 0 and day 15 of differentiation. EV and cell preparations were visualised by electron microscopy and EVs quantified by nanoparticle tracking analysis (NTA). EVs were then assessed for annexin V positivity using flow cytometry; lipid and phospholipid composition using 2D thin layer chromatography and gas chromatography; and vesicular protein content by an immuno-phenotyping assay. Pre-adipogenic cells are connected via a network of protrusions and EVs at both time points display classic EV morphology. EV concentration is elevated prior to adipogenesis, particularly in exosomes and small microvesicles. Parent cells contain higher proportions of phosphatidylserine (PS) and show higher annexin V binding. Both cells and EVs contain an increased proportion of arachidonic acid at day 0. PREF-1 was increased at day 0 whilst adiponectin was higher at day 15 indicating EV protein content reflects the stage of adipogenesis of the cell. Our data suggest that EV production is higher in cells before adipogenesis, particularly in vesicles <300 nm. Cells at this time point possess a greater proportion of PS (required for EV generation) whilst corresponding EVs are enriched in signalling fatty acids, such as arachidonic acid, and markers of adipogenesis, such as PREF-1 and PPARγ.