Endothelial microparticles affect angiogenesis in vitro: role of oxidative stress

Extracellular Vesicles: A Novel Target for Exercise-Mediated Reductions in Type 2 Diabetes and Cardiovascular Disease Risk

Regular exercise is important for reducing type 2 diabetes (T2D) and/or cardiovascular disease (CVD) risk. However, only about 40-50% of this CVD risk reduction is accounted for by adiposity, hyperglycemia, hypertension, and dyslipidemia. Herein, we present the novel hypothesis that extracellular vesicles (EVs) are candidate biomarkers that may relate to impaired endothelial function and insulin resistance independent of obesity risk factors. EVs are small membrane-bound particles that are generated by cells following stimulation, stress, or activation. They carry markers of their parent cell and are thought to be potent bioactivators and communicators. We discuss the underlying physiology of specific cell type EVs, as well as examine how acute and chronic exercise interventions impact EV count and phenotype. We also propose that current gaps in the field are in part related to use of different detection techniques and the lack of standardized measurements of EV affecting the pre- and postanalytical phase. Ultimately, improving the understanding of how EVs impact cardiometabolic health and their function will lead to improved approaches for enhancing diagnostic options as well as designing exercise interventions that treat and/or prevent T2D and CVD.

Putative mechanisms Underlying Myocardial infarction onset and Emotions (PUME): a randomised controlled study protocol

INTRODUCTION

The experience of negative emotions (eg, anger, anxiety and sadness) is associated with an increased short-term risk of incident cardiovascular disease (CVD) events, independent of traditional CVD risk factors. Impairment in endothelial function is one possible biological mechanism which may explain the association between negative emotions and incident CVD events. This laboratory-based, single-blind, randomised controlled experimental study aims to investigate the impact of induced negative emotions including anger, anxiety and sadness on endothelial function.

METHODS AND ANALYSIS

In a between-subjects design, 280 healthy participants are randomised to one of four experimental negative emotion inductions: anger, anxiety, sadness or a neutral condition. Endothelium-dependent vasodilation, circulating levels of endothelial cell-derived microparticles and bone marrow-derived endothelial progenitor cells, and indices of nitric oxide inhibition are assessed before and 3, 40, 70 and 100 min after negative emotion induction. Finally, in a subsample of 84 participants, the potential moderating effects of cardiorespiratory fitness and habitual physical activity on the adverse effects of an acute negative emotion on endothelial function are investigated.

ETHICS AND DISSEMINATION

This study is conducted in compliance with the Helsinki Declaration and the Columbia University Medical Center Institutional Review Board. The results of the study will be disseminated at several research conferences and as published articles in peer reviewed journals. The study will be implemented and reported in line with the SPIRIT statement.

TRIAL REGISTRATION NUMBER

NCT01909895; Pre-results.

Yoga and immune system functioning: a systematic review of randomized controlled trials

Yoga is an ancient mind-body practice that is increasingly recognized to have health benefits in a variety of clinical and non-clinical conditions. This systematic review summarizes the findings of randomized controlled trials examining the effects of yoga on immune system functioning which is imperative to justify its application in the clinic. Fifteen RCTs were eligible for the review. Even though the existing evidence is not entirely consistent, a general pattern emerged suggesting that yoga can downregulate pro-inflammatory markers. In particular, the qualitative evaluation of RCTs revealed decreases in IL-1beta, as well as indications for reductions in IL-6 and TNF-alpha. These results imply that yoga may be implemented as a complementary intervention for populations at risk or already suffering from diseases with an inflammatory component. Beyond this, yoga practice may exert further beneficial effects by enhancing cell-mediated and mucosal immunity. It is hypothesized that longer time spans of yoga practice are required to achieve consistent effects especially on circulating inflammatory markers. Overall, this field of investigation is still young, hence the current body of evidence is small and for most immune parameters, more research is required to draw distinct conclusions.

Microvesicles in Atherosclerosis and Angiogenesis: From Bench to Bedside and Reverse

Atherosclerosis (AT) is a progressive chronic disease involving lipid accumulation, fibrosis, and inflammation in medium and large-sized arteries, and it is the main cause of cardiovascular disease (CVD). AT is caused by dyslipidemia and mediated by both innate and adaptive immune responses. Despite lipid-lowering drugs have shown to decrease the risk of cardiovascular events (CVEs), there is a significant burden of AT-related morbidity and mortality. Identification of subjects at increased risk for CVE as well as discovery of novel therapeutic targets for improved treatment strategies are still unmet clinical needs in CVD. Microvesicles (MVs), small extracellular plasma membrane particles shed by activated and apoptotic cells have been widely linked to the development of CVD. MVs from vascular and resident cells by facilitating exchange of biological information between neighboring cells serve as cellular effectors in the bloodstream and play a key role in all stages of disease progression. This article reviews the current knowledge on the role of MVs in AT and CVD. Attention is focused on novel aspects of MV-mediated regulatory mechanisms from endothelial dysfunction, vascular wall inflammation, oxidative stress, and apoptosis to coagulation and thrombosis in the progression and development of atherothrombosis. MV contribution to vascular remodeling is also discussed, with a particular emphasis on the effect of MVs on the crosstalk between endothelial cells and smooth muscle cells, and their role regulating the active process of AT-driven angiogenesis and neovascularization. This review also highlights the latest findings and main challenges on the potential prognostic, diagnostic, and therapeutic value of cell-derived MVs in CVD. In summary, MVs have emerged as new regulators of biological functions in atherothrombosis and might be instrumental in cardiovascular precision medicine; however, significant efforts are still needed to translate into clinics the latest findings on MV regulation and function.

Vitamin D suppresses oxidative stress-induced microparticle release by human umbilical vein endothelial cells

Endothelial microparticle (MP) release was increased in numerous cardiovascular diseases including preeclampsia. Oxidative stress is a potent inducer of endothelial dysfunction. In this study, we aimed to investigate if vitamin D could protect endothelial cells (ECs) from MP release induced by oxidative stress. Endothelial cell (from human umbilical vein) oxidative stress was induced by cultivation of cells under lowered oxygen condition (2%O2) for 48 h and cells cultured under standard condition (21%O2) served as control. 1,25(OH)2D3 was used as bioactive vitamin D. Using annexin-V as a marker of released MP assessed by flow cytometry and cytochrome c reduction assay to measure EC superoxide generation, we found that MP release and superoxide generation were significantly increased when cells were cultured under 2%O2, which could be significantly inhibited by 1,25(OH)2D3. To study the potential mechanisms of 1,25(OH)2D3 protective effects on ECs, EC expression of endothelial nitric oxide synthase (eNOS), p-eNOSSer1177, p-eNOSThr495, caveolin-1, extracellular signal-regulated kinase (ERK), p-ERK, Akt, p-AktSer473, Rho-associated coiled-coil protein kinase 1 (ROCK1), and vitamin D receptor were determined. Microparticle expression of eNOS and caveolin-1 were also determined. We found that under lowered oxygen condition, 1,25(OH)2D3 could upregulate EC eNOS, p-eNOSSer1177, and p-AktSer473 expression, but inhibit cleaved ROCK1 expression. The upregulatory and inhibitory effects induced by 1,25(OH)2D3 were dose dependent. Strikingly, we also found that oxidative stress-induced decrease in ratio of eNOS and caveolin-1 expression in MP could be attenuated when 1,25(OH)2D3 was present in culture. These results suggest that upregulation of eNOSSer1177 and AktSer473 phosphorylation and inhibition of ROCK1 cleavage in EC and modulation of eNOS and caveolin-1 expression in MP could be plausible mechanisms of vitamin D protective effects on ECs.

Vitamin D suppresses oxidative stress-induced microparticle release by human umbilical vein endothelial cells

Endothelial microparticle (MP) release was increased in numerous cardiovascular diseases including preeclampsia. Oxidative stress is a potent inducer of endothelial dysfunction. In this study, we aimed to investigate if vitamin D could protect endothelial cells (ECs) from MP release induced by oxidative stress. Endothelial cell (from human umbilical vein) oxidative stress was induced by cultivation of cells under lowered oxygen condition (2%O2) for 48 h and cells cultured under standard condition (21%O2) served as control. 1,25(OH)2D3 was used as bioactive vitamin D. Using annexin-V as a marker of released MP assessed by flow cytometry and cytochrome c reduction assay to measure EC superoxide generation, we found that MP release and superoxide generation were significantly increased when cells were cultured under 2%O2, which could be significantly inhibited by 1,25(OH)2D3. To study the potential mechanisms of 1,25(OH)2D3 protective effects on ECs, EC expression of endothelial nitric oxide synthase (eNOS), p-eNOSSer1177, p-eNOSThr495, caveolin-1, extracellular signal-regulated kinase (ERK), p-ERK, Akt, p-AktSer473, Rho-associated coiled-coil protein kinase 1 (ROCK1), and vitamin D receptor were determined. Microparticle expression of eNOS and caveolin-1 were also determined. We found that under lowered oxygen condition, 1,25(OH)2D3 could upregulate EC eNOS, p-eNOSSer1177, and p-AktSer473 expression, but inhibit cleaved ROCK1 expression. The upregulatory and inhibitory effects induced by 1,25(OH)2D3 were dose dependent. Strikingly, we also found that oxidative stress-induced decrease in ratio of eNOS and caveolin-1 expression in MP could be attenuated when 1,25(OH)2D3 was present in culture. These results suggest that upregulation of eNOSSer1177 and AktSer473 phosphorylation and inhibition of ROCK1 cleavage in EC and modulation of eNOS and caveolin-1 expression in MP could be plausible mechanisms of vitamin D protective effects on ECs.

[Membranous microparticles and respiratory disease]

Microparticles (MP) are plasmic membrane fragments released from cells after physiological stimulation or stress conditions like inflammation or infection. Their production is correlated to the rate of cell apoptosis. All types of cells can produce MP but they are produced mainly by platelets, endothelial cells, and leukocytes. They carry many bio-active molecules on their surface, specific to the parental cell, giving them the ability to be biomarkers and bio-effectors. MP are present in circulating blood, tissues and many biological fluids. Circulating MP levels can change during the course of many diseases. They have been the subject of many studies in the fields of cardiovascular disease and oncology. In the lungs, they are present in circulating blood and in the airways. They seem to have a role in pulmonary homeostasis in physiological situations and also in the expression of several disease processes. In this review of the literature, we were interested in the quantitative and qualitative variations in MP and their impact in airway diseases like chronic obstructive pulmonary disease (COPD) and asthma, pulmonary fibrosis and pulmonary hypertension.

Inhibition of Caveolae Contributes to Propofol Preconditioning-Suppressed Microvesicles Release and Cell Injury by Hypoxia-Reoxygenation

Endothelial microvesicles (EMVs), released after endothelial cell (EC) apoptosis or activation, may carry many adverse signals and propagate injury by intercellular transmission. Caveolae are 50–100 nm cell surface plasma membrane invaginations involved in many pathophysiological processes. Recent evidence has indicated EMVs and caveolae may have functional effects in cells undergoing H/R injury. Propofol, a widely used anaesthetic, confers antioxidative stress capability in the same process. But the connection between EMVs, H/R, and caveolae remains largely unclear. Here, we found that H/R significantly increased the release of EMVs, the expression of CAV-1 (the structural protein responsible for maintaining the shape of caveolae), oxidative stress, and the mitochondrial damage, and all these changes were inhibited by propofol preconditioning. Interestingly, the caveolae inhibitor Mβ-CD strengthened the protective effect of propofol preconditioning. We further found that the release of EMVs is more significantly reduced under propofol preconditioning in the presence of the caveolae inhibitor Mβ-CD. EMVs released from H/R-treated cells caused a substantially increased mitochondrial and cellular damage to normal HUVECs after 4 hours of coculture. Thus, we conclude that inhibition of caveolae contributes to propofol preconditioning-suppressed microvesicles release and cell injury by H/R.

Microvesicles Derived from Indoxyl Sulfate Treated Endothelial Cells Induce Endothelial Progenitor Cells Dysfunction

Cardiovascular disease is a major cause of mortality in chronic kidney disease patients. Indoxyl sulfate (IS) is a typical protein-bound uremic toxin that cannot be effectively cleared by conventional dialysis. Increased IS is associated with the progression of chronic kidney disease and development of cardiovascular disease. After endothelial activation by IS, cells release endothelial microvesicles (EMV) that can induce endothelial dysfunction. We developed an in vitro model of endothelial damage mediated by IS to evaluate the functional effect of EMV on the endothelial repair process developed by endothelial progenitor cells (EPCs). EMV derived from IS-treated endothelial cells were isolated by ultracentrifugation and characterized for miRNAs content. The effects of EMV on healthy EPCs in culture were studied. We observed that IS activates endothelial cells and the generated microvesicles (IsEMV) can modulate the classic endothelial roles of progenitor cells as colony forming units and form new vessels in vitro. Moreover, 23 miRNAs were contained in IsEMV including four (miR-181a-5p, miR-4454, miR-150-5p, and hsa-let-7i-5p) that were upregulated in IsEMV compared with control endothelial microvesicles. Other authors have found that miR-181a-5p, miR-4454, and miR-150-5p are involved in promoting inflammation, apoptosis, and cellular senescence. Interestingly, we observed an increase in NFκB and p53, and a decrease in IκBα in EPCs treated with IsEMV. Our data suggest that IS is capable of inducing endothelial vesiculation with different membrane characteristics, miRNAs and other molecules, which makes maintaining of vascular homeostasis of EPCs not fully functional. These specific characteristics of EMV could be used as novel biomarkers for diagnosis and prognosis of vascular disease.

Endothelial microparticles act as novel diagnostic and therapeutic biomarkers of circulatory hypoxia-related diseases: a literature review

Circulatory hypoxia-related diseases (CHRDs), including acute coronary syndromes, stroke and organ transplantation, attract increased attention due to high morbidity and mortality. Mounting evidence shows that hypoxia-induced oxidative stress, coagulation, inflammation and angiogenesis play extremely important roles in the physiological and pathological processes of CHRD-related vascular endothelial injury. Interestingly, hypoxia, even hypoxia-induced oxidative stress, coagulation and inflammation can all induce release of endothelial microparticles (EMPs). EMPs, shed from activated or apoptotic endothelial cells (ECs), reflect the degree of EC damage, and elevated EMP levels are found in several CHRDs. Furthermore, EMPs, which play an important role in cell-to-cell communication and function, have confirmed pro-coagulant, proinflammatory, angiogenic and other functions, affecting pathological processes. These findings suggest that EMPs and CHRDs have a very close relationship, and EMPs may help to identify CHRD phenotypes and stratify the severity of disease, to improve risk stratification for developing CHRDs, to better define prophylactic strategies and to ameliorate prognostic characterization of patients with CHRDs. This review summarizes the known and potential roles of EMPs in the diagnosis, staging, treatment and clinical prognosis of CHRDs.

Extracellular Vesicles in Angiogenesis

During the past decade, extracellular vesicles (EVs), which include apoptotic bodies, microvesicles, and exosomes, have emerged as important players in cell-to-cell communication in normal physiology and pathological conditions. EVs encapsulate and convey various bioactive molecules that are further transmitted to neighboring or more distant cells, where they induce various signaling cascades. The message delivered to the target cells is dependent on EV composition, which, in turn, is determined by the cell of origin and the surrounding microenvironment during EV biogenesis. Among their multifaceted role in the modulation of biological responses, the involvement of EVs in vascular development, growth, and maturation has been widely documented and their potential therapeutic application in regenerative medicine or angiogenesis-related diseases is drawing increasing interest. EVs derived from various cell types have the potential to deliver complex information to endothelial cells and to induce either pro- or antiangiogenic signaling. As dynamic systems, in response to changes in the microenvironment, EVs adapt their cargo composition to fine-tune the process of blood vessel formation. This article reviews the current knowledge on the role of microvesicles and exosomes from various cellular origins in angiogenesis, with a particular emphasis on the underlying mechanisms, and discusses the main challenges and prerequisites for their therapeutic applications.

Extracellular vesicles in renal disease

Extracellular vesicles, such as exosomes and microvesicles, are host cell-derived packages of information that allow cell-cell communication and enable cells to rid themselves of unwanted substances. The release and uptake of extracellular vesicles has important physiological functions and may also contribute to the development and propagation of inflammatory, vascular, malignant, infectious and neurodegenerative diseases. This Review describes the different types of extracellular vesicles, how they are detected and the mechanisms by which they communicate with cells and transfer information. We also describe their physiological functions in cellular interactions, such as in thrombosis, immune modulation, cell proliferation, tissue regeneration and matrix modulation, with an emphasis on renal processes. We discuss how the detection of extracellular vesicles could be utilized as biomarkers of renal disease and how they might contribute to disease processes in the kidney, such as in acute kidney injury, chronic kidney disease, renal transplantation, thrombotic microangiopathies, vasculitides, IgA nephropathy, nephrotic syndrome, urinary tract infection, cystic kidney disease and tubulopathies. Finally, we consider how the release or uptake of extracellular vesicles can be blocked, as well as the associated benefits and risks, and how extracellular vesicles might be used to treat renal diseases by delivering therapeutics to specific cells.

A Meta-Analysis of Circulating Microvesicles in Patients with Myocardial Infarction

BACKGROUND:

Cell-derived microvesicles (MVs) are vesicles released from activated or apoptotic cells. However, the levels of MVs in myocardial infarction have been found inconsistent in researches.

OBJECTIVE:

To assess the association between MVs and myocardial infarction by conducting a meta-analysis.

METHODS:

A systematic literature search on PubMed, Embase, Cochran, Google Scholar electronic database was conducted. Comparison of the MVs levels between myocardial infarction patients and healthy persons were included in our study. Standard Mean Difference (SMD) and 95% confidence interval (CI) in groups were calculated and meta-analyzed.

RESULTS:

11 studies with a total of 436 participants were included. Compared with the health persons, AMVs [SMD = 3.65, 95% CI (1.03, 6.27)], PMVs [SMD = 2.88, 95% CI (1.82, 3.93),] and EMVs [SMD = 2.73, 95% CI (1.13, 4.34)], levels were higher in patients with myocardial infarction. However, LMVs levels [SMD = 0.73, 95% CI (-0.57, 2.03)] were not changed significantly in patients with myocardial infarction.

CONCLUSIONS:

AMVs, PMVs and EMVs might be potential biomarkers for myocardial infarction.

FUNDAMENTOS:

As microvesículas derivadas de células (MVs) são vesículas liberadas de células ativadas ou apoptóticas. No entanto, os níveis de MVs no infarto do miocárdio foram encontrados inconsistentes nas pesquisas.

OBJETIVO:

Avaliar a associação entre MV e infarto do miocárdio por meio de uma meta-análise.

MÉTODOS:

Foi realizada uma pesquisa sistemática na literatura em PubMed, Embase, Cochran e no banco de dados eletrônico do Google Scholar. Uma comparação dos níveis de MV entre pacientes com infarto do miocárdio e pessoas saudáveis foi incluída no nosso estudo. A Diferença Média Padrão (DMP) e o intervalo de confiança (IC) de 95% nos grupos foram calculadas e meta-analisadas.

RESULTADOS:

Foram incluídos 11 estudos com um total de 436 participantes. Em comparação com as pessoas saudáveis, as MVA [DMP = 3,65, IC 95% (1,03, 6,27)], MVPs [DMP = 2,88, IC 95% (1,82, 3,93)] e MVEs [DMP = 2,73, IC 95% (1,13, 4.34)], foram maiores em pacientes com infarto do miocárdio. No entanto, os níveis de MVL [DMP = 0,73, IC 95% (-0,57, 2,03)] não foram alterados significativamente em pacientes com infarto do miocárdio.

CONCLUSÕES:

MVAs, MVPs e MVEs podem ser biomarcadores potenciais para o infarto do miocárdio.

Circulating microparticles are prognostic biomarkers in advanced non-small cell lung cancer patients

We investigated whether circulating microparticles (MPs) could serve as prognostic biomarkers in non-small cell lung cancer (NSCLC) patients. We enrolled 25 control subjects and 136 NSCLC patients categorized into disease-progression (DP, n=42) and disease-control (DC, n=94) groups. Flow cytometric analysis showed that levels of four types of circulating microparticles (EDAc-MPs, EDAp-MPs, PDAc-MPs and PDAp-MPs) were higher in the study patients than the control subjects (P < 0.04). DP patients showed poor initially performance status and more non-adenocarcinomas than DC patients. DC patients showed more EGFR mutations and poorer performance to targeted therapy than DP patients (P < 0.01). Three months after therapy, the levels of all four types of circulating MPs were lower in DC than DP patients (P < 0.02), and were comparable to the levels in control subjects. In addition, the levels of circulating MPs after 3 months accurately predicted one-year prognostic outcomes (P < 0.05). This study showed that circulating MPs are valuable prognostic biomarkers in advanced NSCLC patients.

Microvesicles in vascular homeostasis and diseases. Position Paper of the European Society of Cardiology (ESC) Working Group on Atherosclerosis and Vascular Biology

Microvesicles are members of the family of extracellular vesicles shed from the plasma membrane of activated or apoptotic cells. Microvesicles were initially characterised by their pro-coagulant activity and described as "microparticles". There is mounting evidence revealing a role for microvesicles in intercellular communication, with particular relevance to hemostasis and vascular biology. Coupled with this, the potential of microvesicles as meaningful biomarkers is under intense investigation. This Position Paper will summarise the current knowledge on the mechanisms of formation and composition of microvesicles of endothelial, platelet, red blood cell and leukocyte origin. This paper will also review and discuss the different methods used for their analysis and quantification, will underline the potential biological roles of these vesicles with respect to vascular homeostasis and thrombosis and define important themes for future research.

Endothelial Extracellular Vesicles-Promises and Challenges

Extracellular vesicles, including exosomes, microparticles, and apoptotic bodies, are phospholipid bilayer-enclosed vesicles that have once been considered as cell debris lacking biological functions. However, they have recently gained immense interest in the scientific community due to their role in intercellular communication, immunity, tissue regeneration as well as in the onset, and progression of various pathologic conditions. Extracellular vesicles of endothelial origin have been found to play a versatile role in the human body, since they are on the one hand known to contribute to cardiovascular diseases, but on the other hand have also been reported to promote endothelial cell survival. Hence, endothelial extracellular vesicles hold promising therapeutic potential to be used as a new tool to detect as well as treat a great number of diseases. This calls for clinically approved, standardized, and efficient isolation and characterization protocols to harvest and purify endothelial extracellular vesicles. However, such methods and techniques to fulfill stringent requirements for clinical trials have yet to be developed or are not harmonized internationally. In this review, recent advances and challenges in the field of endothelial extracellular vesicle research are discussed and current problems and limitations regarding isolation and characterization are pointed out.

The answer is blowing in the wind: an uncommon cause for severe ARDS accompanied by circulatory insufficiency requiring extracorporeal membrane oxygenation

We report a rare complication in an immunosuppressed patient with IgA nephropathy who suffered from severe acute respiratory distress syndrome, severe capillary leakage and shock after placement of a double lumen central venous catheter. He could be successfully treated by extracorporeal membrane oxygenation (ECMO) and therapeutic plasma exchange. This report highlights the severity of late-onset complications of catheter placements and shows the potential of ECMO treatment for the management of acute illnesses with bridge to recovery.

Divergent endothelial function but similar platelet microvesicle responses following eccentric and concentric cycling at a similar aerobic power output

Endothelial function and microvesicle concentration changes after acute bouts of continuous eccentric exercise have not been assessed previously nor compared with concentric exercise at similar aerobic power outputs. This method of training may be useful among some clinical populations, but acute responses are not well described. As such, 12 healthy males completed 2 experimental sessions of either 45 min of eccentric or concentric cycling at a matched aerobic power output below the ventilatory threshold. Brachial artery vascular function was assessed throughout 5 min of forearm ischemia and 3 min thereafter, before and at 5 and 40 min of recovery following each exercise session [flow-mediated dilation (FMD)]. Venous blood samples were acquired before each vascular function assessment. FMD significantly decreased after eccentric cycling by 40 min of recovery (P < 0.05), but was unaltered after concentric exercise. No differences in peak hyperemic blood flow velocity occurred neither between modalities nor at any time point (P > 0.05). Platelet-derived microvesicles increased by ~20% after both exercise modalities (P < 0.05) while endothelial-derived microvesicles were unchanged (P > 0.05). Moderate relationships with cardiac output, a surrogate for shear stress, and norepinephrine were apparent (P < 0.05), but there were no relationships with inflammatory or acute phase proteins. In summary, eccentric endurance exercise induced macrovascular endothelial dysfunction; however, endothelial activation determined by endothelial microvesicles did not occur suggesting that this modality may induce oxidative stress but no significant endothelial damage. In addition, the increase in platelet microvesicle concentrations may induce beneficial microvascular adaptations as suggested by previous research.NEW & NOTEWORTHY Continuous eccentric cycling exercise induces substantial skeletal muscle, tendon, and bone strain providing a potentially beneficial stimulus among clinical populations. This modality also induces temporary endothelial dysfunction but no apparent damage or activation of the endothelium indicated by microvesicle production, whereas proangiogenic platelet microvesicles are released similarly following both concentric and eccentric cycling and may relate to the shear stress and catecholamine response to exercise.

Bubble-Induced Endothelial Microparticles Promote Endothelial Dysfunction

Decompression sickness is a systemic pathophysiological process caused by bubbles and endothelial microparticles (EMPs) are established markers reflecting competency of endothelial function and vascular biology. Here, we investigated the effects of bubble-induced EMPs on endothelial cells in vitro and vivo. Rat pulmonary microvascular endothelial cells (PMVECs) were isolated and stimulated by bubbles and bubble-induced EMPs were collected and incubated with normal PMVECs in vitro. Cell viability and apoptosis were detected using Cell Counting Kit-8 assay and Annexin V FITC/PI double staining, respectively. Cell permeability and pro-inflammatory cytokines were determined by electric cell substrate impedance sensing and enzyme-linked immunosorbent assay, respectively. Intracellular nitric oxide and reactive oxygen species production were analyzed microscopically. In vivo study, bubble-induced EMPs were intravenously injected to the rats and soluble thrombomodulin, intercellular adhesion molecule 1, and vascullar adhesion molecule 1 were involved in evaluating endothelial dysfunction. In our study, bubble stimulus resulted in a significant increase of EMPs release by 3 fold. Bubble-induced EMPs significantly decreased cell viability and increased cell apoptosis. Moreover, bubble-induced EMPs induced abnormal increase of cell permeability and over-expression of pro-inflammatory cytokines. Intracellular ROS production increased while NO production decreased. These negative effects caused by bubble-induced EMPs were remarkably suppressed when EMPs pretreated with surfactant FSN-100. Finally, intravenous injection of bubble-induced EMPs caused elevations of soluble thrombomodulin and pro-inflammatory cytokines in the circulation. Altogether, our results demonstrated that bubble-induced EMPs can mediate endothelial dysfunction in vitro and vivo, which can be attenuated by EMPs abatement strategy. These data expanded our horizon of the detrimental effects of bubble-induced EMPs, which may be of great concern in DCS.

Endothelial Microparticles Act as Novel Diagnostic and Therapeutic Biomarkers of Diabetes and Its Complications: A Literature Review

Diabetes mellitus- (DM-) related vascular diseases attract increased attention due to their high morbidity and mortality. The incidence of obesity, atherosclerosis, coronary heart disease, hypertension, and dyslipidemia is significantly higher in DM patients, with an earlier onset and faster progression compared with non-DM patients. DM-related vascular diseases including macrovascular and microvascular complications are characterized by endothelial dysfunction. Therefore, a better understanding of the etiology and mechanisms of endothelial dysfunction is important for the diagnosis and treatment of DM. Endothelial microparticles (EMPs) are new diagnostic and therapeutic targets and biomarkers in DM-related vascular disease. Circulating EMPs containing biologically active substances act as intercellular signals under physiological and pathological conditions. They serve as biological markers of altered vascular endothelium and reflect the pathological progression and diminished endothelial function of blood vessels. Recent evidence suggests that the plasma level of EMPs is significantly higher in DM patients than in healthy population and is significantly correlated with DM-related complications. These observations have prompted speculation that EMPs play a crucial role in the pathophysiology of DM. This review summarizes the known and potential roles of EMPs in the diagnosis, staging, treatment, and clinical prognosis of DM and related vascular diseases.

Effects of 8-Week Hatha Yoga Training on Metabolic and Inflammatory Markers in Healthy, Female Chinese Subjects: A Randomized Clinical Trial

We aimed to determine the effects of an 8 wk Hatha yoga training on blood glucose, insulin, lipid profiles, endothelial microparticles (EMPs), and inflammatory status in healthy, lean, and female Chinese subjects. A total of 30 healthy, female Chinese subjects were recruited and randomized into control or yoga practice group. The yoga practice included 8 wks of yoga practice (2 times/wk) for a total of 16 times. Fasting blood samples were collected before and after yoga training. Plasma was isolated for the measurement of lipid profiles, glucose, insulin, EMPs, and inflammatory cytokines. Whole blood was cultured ex vivo and stimulated with lipopolysaccharide (LPS) and Pam3Cys-SK4. Peripheral blood mononuclear cells (PBMCs) were isolated for the measurement of TLR2 and TLR4 protein expression. Yoga practice significantly reduced plasma cholesterol, LDL-cholesterol, insulin levels, and CD31+/CD42b- EMPs. Cultured whole blood from the yoga group has reduced proinflammatory cytokines secretion both at unstimulated condition and when stimulated with Pam3Cys-SK4; this might be associated with reduced TLR2 protein expression in PBMCs after yoga training. Hatha yoga practice in healthy Chinese female subjects could improve hallmarks related to MetS; thus it can be considered as an ancillary intervention in the primary MetS prevention for the healthy population. This trial is registered with ChiCTR-IOR-14005747.

Microvesicles in Autoimmune Diseases

During apoptosis or activation, cells can release a subcellular structure, called a membrane microvesicle (also known as microparticle) into the extracellular environment. Microvesicles bud-off as a portion of cell membrane with its associated proteins and lipids surrounding a cytosolic core that contains intracellular proteins, lipids, and nucleic acids (DNA, RNA, siRNA, microRNA, lncRNA). Biologically active molecules on the microvesicle surface and encapsulated within can act on recipient cells as a novel mode of intercellular communication. Apoptosis has long been known to be involved in the development of diseases of autoimmunity. Abnormally persistent microvesicles, particularly apoptotic microvesicles, can accelerate autoimmune responses locally in specific organs and tissues as well as systemically. In this review, we focus on studies implicating microvesicles in the pathogenesis of autoimmune diseases and their complications.

Microvesicles derived from hypoxia/reoxygenation-treated human umbilical vein endothelial cells promote apoptosis and oxidative stress in H9c2 cardiomyocytes

Background

Vascular endothelial dysfunction is the closely related determinant of ischemic heart disease (IHD). Endothelial dysfunction and ischemia/reperfusion injury (IRI) have been associated with an increase in microvesicles (MVs) in vivo. However, the potential contribution of endothelial microvesicles (EMVs) to myocardial damage is unclear. Here we aimed to investigate the role of EMVs derived from hypoxia/reoxygenation (H/R) -treated human umbilical vein endothelial cells (HUVECs) on cultured H9c2 cardiomyocytes.

Results

H/R injury model was established to induce HUVECs to release H/R-EMVs. The H/R-EMVs from HUVECs were isolated from the conditioned culture medium and characterized. H9c2 cardiomyocytes were then incubated with 10, 30, 60 μg/mL H/R-EMVs for 6 h. We found that H9c2 cells treated by H/R-EMVs exhibited reduced cell viability, increased cell apoptosis and reactive oxygen species (ROS) production. Moreover mechanism studies demonstrated that H/R-EMVs could induce the phosphorylation of p38 and JNK1/2 in H9c2 cells in a dose-dependent manner. In addition, H/R-EMVs contained significantly higher level of ROS than EMVs generated from untreated HUVECs, which might be a direct source to trigger a cascade of myocardial damage.

Conclusion

We showed that EMVs released during H/R injury are pro-apoptotic, pro-oxidative and directly pathogenic to cardiomyocytes in vitro. EMVs carry ROS and they may impair myocardium by promoting apoptosis and oxidative stress. These findings provide new insights into the pathogenesis of IRI.

Flow Cytometric Quantification of Peripheral Blood Cell β-Adrenergic Receptor Density and Urinary Endothelial Cell-Derived Microparticles in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a heterogeneous disease characterized by severe angiogenic remodeling of the pulmonary artery wall and right ventricular hypertrophy. Thus, there is an increasing need for novel biomarkers to dissect disease heterogeneity, and predict treatment response. Although β-adrenergic receptor (βAR) dysfunction is well documented in left heart disease while endothelial cell-derived microparticles (Ec-MPs) are established biomarkers of angiogenic remodeling, methods for easy large clinical cohort analysis of these biomarkers are currently absent. Here we describe flow cytometric methods for quantification of βAR density on circulating white blood cells (WBC) and Ec-MPs in urine samples that can be used as potential biomarkers of right heart failure in PAH. Biotinylated β-blocker alprenolol was synthesized and validated as a βAR specific probe that was combined with immunophenotyping to quantify βAR density in circulating WBC subsets. Ec-MPs obtained from urine samples were stained for annexin-V and CD144, and analyzed by a micro flow cytometer. Flow cytometric detection of alprenolol showed that βAR density was decreased in most WBC subsets in PAH samples compared to healthy controls. Ec-MPs in urine was increased in PAH compared to controls. Furthermore, there was a direct correlation between Ec-MPs and Tricuspid annular plane systolic excursion (TAPSE) in PAH patients. Therefore, flow cytometric quantification of peripheral blood cell βAR density and urinary Ec-MPs may be useful as potential biomarkers of right ventricular function in PAH.

Endothelial Microparticle-Derived Reactive Oxygen Species: Role in Endothelial Signaling and Vascular Function

Endothelial microparticles are effectors of endothelial damage; however mechanisms involved are unclear. We examined the effects of eMPs on cultured endothelial cells (ECs) and isolated vessels and investigated the role of eMP-derived reactive oxygen species (ROS) and redox signaling in these processes. eMPs were isolated from EC media and their ability to directly produce ROS was assessed by lucigenin and liquid chromatography. Nicotinamide adenine dinucleotide phosphate oxidase (Nox) subunits were probed by Western blot. ECs were treated with eMPs and effects on kinase signaling, superoxide anion (O₂^∙−) generation, and nitric oxide (NO) production were examined. Acetylcholine-mediated vasorelaxation was assessed by myography in eMP-treated mesenteric arteries. eMPs contained Nox1, Nox2, Nox4, p47^phox, p67^phox, and p22^phox and they produced ROS which was inhibited by the Nox inhibitor, apocynin. eMPs increased phosphorylation of ERK1/2 and Src, increased O₂^∙− production, and decreased A23187-induced NO production in ECs. Pretreatment of eMPs with apocynin diminished eMP-mediated effects on ROS and NO production but had no effect on eMP-mediated kinase activation or impairment in vasorelaxation. Our findings identify a novel mechanism whereby eMP-derived ROS contributes to MP bioactivity. These interactions may be important in conditions associated with vascular injury and increased eMP formation.

Activated Stat5 trafficking Via Endothelial Cell-derived Extracellular Vesicles Controls IL-3 Pro-angiogenic Paracrine Action

Soluble factors and cell-derived extracellular vesicles (EVs) control vascular cell fate during inflammation. The present study investigates the impact of Interleukin 3 (IL-3) on EV release by endothelial cells (ECs), the mechanisms involved in EV release and paracrine actions. We found that IL-3 increases EV release, which is prevented by IL-3Ralpha blockade. EVs released upon IL-3 stimulation were able to induce pro-angiogenic signals as shown by chromatin immunoprecipitation (ChIP) assay performed on the promoter region of cyclin D1 and tridimensional tube-like structure formation. We herein demonstrate that these effects rely on the transfer of miR-126-3p, pre-miR-126 and, more importantly, of activated signal transduction and activator of transcription 5 (pSTAT5) from IL-3-EV cargo into recipient ECs. We show, using the dominant negative form (ΔN)STAT5 and an activated STAT5 (1*6STAT5) constructs, that STAT5 drives IL-3-mediated EV release, miR-126-3p and pSTAT5 content. Finally, using EVs recovered from ΔNSTAT5 expressing ECs, we provide evidence that miR-126-3p and pSTAT5 trafficking is relevant for IL-3-mediated paracrine pro-angiogenic signals. These results indicate that IL-3 regulates EC-EV release, cargo and IL-3 angiogenic paracrine action via STAT5. Moreover, these results provide evidence that EC-derived IL-3-EVs can serve as pro-angiogenic clinical delivery wound healing devices.

Multilayer Membranes of Glycosaminoglycans and Collagen I Biomaterials Modulate the Function and Microvesicle Release of Endothelial Progenitor Cells

Multilayer composite membrane of biomaterials can increase the function of adipose stem cells or osteoprogenitor cells. Recent evidence indicates endothelial progenitor cells (EPCs) and EPCs released microvesicles (MVs) play important roles in angiogenesis and vascular repair. Here, we investigated the effects of biomaterial multilayer membranes of hyaluronic acid (HA) or chondroitin sulfate (CS) and Collagen I (Col I) on the functions and MVs release of EPCs. Layer-by-layer (LBL) technology was applied to construct the multilayer composite membranes. Four types of the membranes constructed by adsorbing either HA or CS and Col I alternatively with different top layers were studied. The results showed that all four types of multilayer composite membranes could promote EPCs proliferation and migration and inhibit cell senility, apoptosis, and the expression of activated caspase-3. Interestingly, these biomaterials increased the release and the miR-126 level of EPCs-MVs. Moreover, the CS-Col I membrane with CS on the top layer showed the most effects on promoting EPCs proliferation, EPCs-MV release, and miR-126 level in EPCs-MVs. In conclusion, HA/CS and Collagen I composed multilayer composite membranes can promote EPCs functions and release of miR-126 riched EPCs-MVs, which provides a novel strategy for tissue repair treatment.

Time courses and value of circulating microparticles in patients with operable stage non-small cell lung cancer undergoing surgical intervention

Microparticles (MPs) are substantially increased in patients with operable stage non-small cell lung cancer (NSCLC) prior to lung resection surgery. This study tested the hypothesis that there is a decrease in MPs after surgical intervention. Between March 2012 and January 2015, 33 patients who had operable stage NSCLC were consecutively and prospectively enrolled into the study. Additionally, 31 healthy subjects who were consecutively enrolled in the study period served as age- and gender-matched controls. Circulating MPs (EDAc-MPs, EDAp-MPs, PDAc-MPs, PDAp-MPs) were measured by flow cytometry once in control subjects and twice (i.e., prior to and three months later after surgical intervention) in NSCLC patients. Compared with control subjects, these four types of circulating MPs were significantly higher in NSCLC patients prior to operation (all P < 0.005), but did not differ among the controls and NSCLC patients at 3 months after surgery (all P > 0.2). Additionally, a receiver operating characteristic curve (ROC) showed that these four types of MPs were significantly valuable predictors for detecting early stage NSCLC (all P < 0.004). Circulating MPs which were remarkably increased in the operable stage of NSCLC prior to surgery were substantially decreased 3 months later after surgery. These findings show that circulating MPs might be an accessory biomarker for monitoring those of NSCLC after receiving lung resection surgery.

Endothelial microparticles carrying hedgehog-interacting protein induce continuous endothelial damage in the pathogenesis of acute graft-versus-host disease

Accumulating evidence suggests that endothelial microparticles (EMPs), a marker of endothelial damage, are elevated in acute graft-versus-host disease (aGVHD), and that endothelial damage is implicated in the pathogenesis of aGVHD, but the mechanisms remain elusive. In this study, we detected the plasma EMP levels and endothelial damage in patients and mice with aGVHD in vivo and then examined the effects of EMPs derived from injured endothelial cells (ECs) on endothelial damage and the role of hedgehog-interacting protein (HHIP) carried by EMPs in these effects in vitro. Our results showed that EMPs were persistently increased in the early posttransplantation phase in patients and mice with aGVHD. Meanwhile, endothelial damage was continuous in aGVHD mice, but was temporary in non-aGVHD mice after transplantation. In vitro, EMPs induced endothelial damage, including increased EC apoptosis, enhanced reactive oxygen species, decreased nitric oxide production and impaired angiogenic activity. Enhanced expression of HHIP, an antagonist for the Sonic hedgehog (SHH) signaling pathway, was observed in patients and mice with aGVHD and EMPs from injured ECs. The endothelial damage induced by EMPs was reversed when the HHIP incorporated into EMPs was silenced with an HHIP small interfering RNA or inhibited with the SHH pathway agonist, Smoothened agonist. This work supports a feasible vicious cycle in which EMPs generated during endothelial injury, in turn, aggravate endothelial damage by carrying HHIP into target ECs, contributing to the continuously deteriorating endothelial damage in the development of aGVHD. EMPs harboring HHIP would represent a potential therapeutic target for aGVHD.

Extracellular vesicles in cardiovascular disease: are they Jedi or Sith?

In the recent past, extracellular vesicles have become recognized as important players in cell biology and biomedicine. Extracellular vesicles, including exosomes, microvesicles and apoptotic bodies, are phospholipid bilayer-enclosed structures found to be secreted by most if not all cells. Extracellular vesicle secretion represents a universal and highly conserved active cellular function. Importantly, increasing evidence supports that extracellular vesicles may serve as biomarkers and therapeutic targets or tools in human diseases. Cardiovascular disease undoubtedly represents one of the most intensely studied and rapidly growing areas of the extracellular vesicle field. However, in different studies related to cardiovascular disease, extracellular vesicles have been shown to exert diverse and sometimes discordant biological effects. Therefore, it might seem a puzzle whether these vesicles are in fact beneficial or detrimental to cardiovascular health. In this review we provide a general introduction to extracellular vesicles and an overview of their biological roles in cardiovascular diseases. Furthermore, we aim to untangle the various reasons for the observed discrepancy in biological effects of extracellular vesicles in cardiovascular diseases. To this end, we provide several examples that demonstrate that the observed functional diversity is in fact due to inherent differences among various types of extracellular vesicles.

Circulating Endothelial Microparticles: A Key Hallmark of Atherosclerosis Progression

The levels of circulating microparticles (MPs) are raised in various cardiovascular diseases. Their increased level in plasma is regarded as a biomarker of alteration in vascular function. The prominent MPs present in blood are endothelial microparticles (EMPs) described as complex submicron (0.1 to 1.0 μm) vesicles like structure, released in response to endothelium cell activation or apoptosis. EMPs possess both physiological and pathological effects and may promote oxidative stress and vascular inflammation. EMPs release is triggered by inducer like angiotensin II, lipopolysaccharide, and hydrogen peroxide leading to the progression of atherosclerosis. However, there are multiple physiological pathways for EMPs generation like NADPH oxidase derived endothelial ROS formation, Rho kinase pathway, and mitogen-activated protein kinases. Endothelial dysfunction is a key initiating event in atherosclerotic plaque formation. Atheroemboli, resulting from ruptured carotid plaques, is a major cause of stroke. Increasing evidence suggests that EMPs play an important role in the pathogenesis of cardiovascular disease, acting as a marker of damage, either exacerbating disease progression or triggering a repair response. In this regard, it has been suggested that EMPs have the potential to act as biomarkers of disease status. This review aims to provide updated information of EMPs in relation to atherosclerosis pathogenesis.

Extracellular Vesicles Activate a CD36-Dependent Signaling Pathway to Inhibit Microvascular Endothelial Cell Migration and Tube Formation

OBJECTIVE

Literature on the effect of cell-derived extracellular vesicles (EV), ≤1 μm vesicles shed from various cell types during activation or apoptosis, on microvascular endothelial cell (MVEC) signaling is conflicting. Thrombospondin-1 and related proteins induce anti-angiogenic signals in MVEC via CD36. CD36 binds EV via phosphatidylserine exposed on their surface but the effects of this interaction on MVEC functions are not known. We hypothesized that EV would inhibit angiogenic MVEC functions via CD36.

APPROACH AND RESULTS

EV generated in vitro from various cell types or isolated from plasma inhibited MVEC tube formation in in vitro matrigel assays and endothelial cell migration in Boyden chamber assays. Exosomes derived from the same cells did not have inhibitory activity. Inhibition of migration required endothelial cell expression of CD36. In mouse in vivo matrigel plug assays, EV inhibited cell migration into matrigel plugs in wild type but not in cd36 null animals. Annexin V, an anionic phospholipid binding protein, when incubated with EV partially reversed inhibition of migration, suggesting a phosphatidylserine-dependent effect. EV exposure induced reactive oxygen species generation in MVEC in a NADPH oxidase and Src family kinase-dependent manner, and their inhibition by apocynin and PP2, respectively, partially reversed the EV-mediated inhibition of migration. Annexin V partially reversed EV-induced reactive oxygen species generation in murine CD36 cDNA-transfected HVUEC but not in CD36-negative human umbilical vein endothelial cell.

CONCLUSIONS

These studies establish a general inhibitory effect of EV on endothelial cell proangiogenic responses and identify a CD36-mediated mechanistic pathway through which EV inhibit MVEC migration and tube formation.

TNFα-Damaged-HUVECs Microparticles Modify Endothelial Progenitor Cell Functional Activity

Endothelial progenitor cells (EPCs) have an important role in the maintenance of vascular integrity and homeostasis. While there are many studies that explain EPCs mechanisms action, there are few studies that demonstrate how they interact with other emerging physiological elements such as Endothelial Microparticles (EMPs). EMPs are membranous structures with a size between 100 and 1000 nm that act as molecular information transporter in biological systems and are known as an important elements in develop different pathologies; moreover a lot of works explains that are novel biomarkers. To elucidate these interactions, we proposed an in vitro model of endothelial damage mediated by TNFalpha, in which damaged EMPs and EPCs are in contact to assess EPCs functional effects. We have observed that damaged EMPs can modulate several EPCs classic factors as colony forming units (CFUs), contribution to repair a physically damaged endothelium (wound healing), binding to mature endothelium, and co-adjuvants to the formation of new vessels in vitro (angiogenesis). All of these in a dose-dependent manner. Damaged EMPs at a concentration of 10³ MPs/ml have an activating effect of these capabilities, while at concentrations of 10⁵ MPs/ml these effects are attenuated or reduced. This in vitro model helps explain that in diseases where there is an imbalance between these two elements (EPCs and damaged EMPs), the key cellular elements in the regeneration and maintenance of vascular homeostasis (EPCs) are not fully functional, and could explain, at least in part, endothelial dysfunction associated in various pathologies.

Role of extracellular vesicles in autoimmune diseases

Extracellular vesicles (EVs) consist of exosomes released upon fusion of multivesicular bodies with the cell plasma membrane and microparticles shed directly from the cell membrane of many cell types. EVs can mediate cell-cell communication and are involved in many processes including inflammation, immune signaling, angiogenesis, stress response, senescence, proliferation, and cell differentiation. Accumulating evidence reveals that EVs act in the establishment, maintenance and modulation of autoimmune processes among several others involved in cancer and cardiovascular complications. EVs could also present biomedical applications, as disease biomarkers and therapeutic targets or agents for drug delivery.

Proteomic research of high-glucose-activated endothelial microparticles and related proteins to Alzheimer's disease

The study was designed to discover the biological function of endotheliocyte-derived microparticles in diabetes condition. A quantitative shotgun proteomics methodology was performed to study the proteome of these high-glucose-activated endothelial microparticles. A total of 1428 proteins were identified, containing 1421 and 1423 proteins in control and high-glucose groups, respectively. According to the ExoCarta database, 669 proteins have previously been identified in microparticles. The proteins associated with disease were identified in this study, and notably, 30 proteins have been reported to be associated with Alzheimer's disease, including amyloid beta A4 protein. Besides, the peptide abundance of amyloid beta A4 protein from control group was much less than that from high-glucose group. In conclusion, this work revealed the proteome of endothelial microparticles in mimic diabetes condition and provided a new proteomic evidence for Alzheimer's disease to be counted as the type 3 diabetes.

Pantethine Prevents Murine Systemic Sclerosis Through the Inhibition of Microparticle Shedding

OBJECTIVE

Endothelial cell (EC) damage in systemic sclerosis (SSc) is reflected by the shedding of microparticles (MPs). The aim of this study was to show that inhibiting MP release using pantethine or by inactivating ATP-binding cassette transporter A1 (ABCA1) ameliorates murine SSc.

METHODS

First, the effects of pantethine on MP shedding and on basal oxidative and nitrosative stresses in ECs and fibroblasts were determined in vitro. The effects of pantethine were then tested in vivo. SSc was induced in BALB/c mice by daily intradermal injection of HOCl. Mice were simultaneously treated daily with pantethine by oral gavage.

RESULTS

In vitro, pantethine inhibited MP shedding from tumor necrosis factor-stimulated ECs and abrogated MP-induced oxidative and nitrosative stresses in ECs and fibroblasts. Ex vivo, pantethine also restored redox homeostasis in fibroblasts from mice with SSc. In vivo, mice with SSc displayed skin and lung fibrosis associated with increased levels of circulating MPs and markers of oxidative and endothelial stress, which were normalized by administration of pantethine or inactivation of ABCA1.

CONCLUSION

Pantethine is a well-tolerated molecule that represents a potential treatment of human SSc.

Predictive role of circulating endothelial-derived microparticles in cardiovascular diseases

Endothelial-derived microparticles (EMPs) are a novel biological marker of endothelium injury and vasomotion disorders that are involved in pathogenesis of cardiovascular, metabolic, and inflammatory diseases. Circulating levels of EMPs are thought to reflect a balance between cell stimulation, proliferation, apoptosis, and cell death. Increased EMPs may be defined in several cardiovascular diseases, such as stable and unstable coronary artery disease, acute and chronic heart failure, hypertension, arrhythmias, thromboembolism, asymptomatic atherosclerosis as well as renal failure, metabolic disorders (including type two diabetes mellitus, abdominal obesity, metabolic syndrome, insulin resistance) and dyslipidemia. This review highlights the controversial opinions regarding impact of circulating EMPs in major cardiovascular and metabolic diseases and summarizes the perspective implementation of the EMPs in risk stratification models.

The predictive role of circulating microparticles in patients with chronic heart failure

AIM

The study aim was to evaluate whether circulating microparticles with apoptotic or non-apoptotic phenotypes are useful for risk assessment of 3-year cumulative fatal and non-fatal cardiovascular events in CHF patients.

METHODS

The incidence of fatal and non-fatal cardiovascular events, as well as the frequency of occurrence of death from any cause in a cohort of 388 patients with CHF during 3 years of observation was studied prospectively. Circulating levels of NT-pro brain natriuretic peptide (NT-pro-BNP), high-sensitivity C-reactive protein (hs-CRP), and endothelial apoptotic microparticles (EMPs) were measured at baseline.

RESULTS

Median follow-up was 2.32 years (IQR = 1.8-3.1). During follow-up, 110 cardiovascular events (including 43 fatal cases) were determined. Additionally, 74 subjects were hospitalized repetitively due to worsening CHF and also 16 subjects were readmitted in the hospital due to other cardiovascular reasons. In the univariate logistic regression analysis, the main factors independently related with cumulative endpoints were creatinine, fasting glucose, HbA1c, total cholesterol, uric acid, various types of EPMs, NT-pro-BNP, hs-CRP, NYHA class, decreased left ventricular ejection fraction (LVEF) less 45%, and type 2 diabetes mellitus. In multivariate model NYHA class, decreased LVEF (less 45%), NT-pro-BNP, hs-CRP, CD144 +/CD31 +/annexin V + EMPs, and CD31 +/annexin V + EMPs remained statistically significant for cumulative endpoint. Adding of CD144 +/CD31 +/annexin V + EMCs and CD31 +/annexin V + EMCs to the standard ABC model may improve the relative IDI for cumulative endpoint by 11.4% and 10.5% respectively.

CONCLUSION

Apoptotic phenotype of circulating microparticles may relate 3-year combined clinical outcomes in CHF patients.

MnTBAP stimulates angiogenic functions in endothelial cells through mitofusin-1

AIMS

Angiogenesis is defined as the sprouting of capillaries from pre-existing vasculature. It is a complex process that includes endothelial proliferation, migration, and tube formation. Previous data have demonstrated a high expression level of manganese-superoxide dismutase (MnSOD) in endothelial cells and suggested an important role of MnSOD in several cardiovascular diseases. In addition, manganese (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP) has been shown to mimic some of the effects of MnSOD in various tissues. However, its effect on the vasculature remains unknown.

METHODS AND RESULTS

HUVECs were treated with MnTBAP. Migration, tube formation, and capillary sprouting assays were performed to evaluate the pro-angiogenic effect in vitro. Matrigel plug assay was performed to assess capillary ingrowth in vivo. Compared to control, treatment with MnTBAP revealed increased cell migration, tube formation and capillary sprouting along with more capillary ingrowth in the Matrigel plug assay. This effect was mediated through a mitofusin (Mfn)-1-dependent pathway. Expression of Tie-2, Ang-2 and VEGF mRNA was increased in muscle tissues after ligation in MnTBAP treated mice. However, revascularization in the hindlimb ischemia model was not statistically significant at day 10 in MnTBAP treated mice.

CONCLUSION

In summary, our data demonstrate a strong pro-angiogenic, but less pro-arteriogenic effect of MnTBAP in HUVECs mediated by Mfn-1.

Microvesicles from platelets: novel drivers of vascular inflammation

Microvesicles are receiving increased attention not only as biomarkers but also as mediators of cell communication and as integral effectors of disease. Platelets present a major source of microvesicles and release these microvesicles either spontaneously or upon activation. Platelet-derived microvesicles retain many features of their parent cells and have been shown to exert modulatory effects on vascular and immune cells. Accordingly, microvesicles from platelets can be measured at increased levels in patients with cardiovascular disease or individuals at risk. In addition, isolated microvesicles from platelets were shown to exert immunomodulatory actions on various cell types. In this review the various aspects of platelet-derived microvesicles including release, clearance, measurement, occurrence during disease and relevance for the pathophysiology of vascular inflammation will be discussed.

Icariin promotes angiogenic differentiation and prevents oxidative stress-induced autophagy in endothelial progenitor cells

Reduced tissue levels of endothelial progenitor cells (EPCs) and functional impairment of endothelium are frequently observed in patients with diabetes and cardiovascular disease. The vascular endothelium is specifically sensitive to oxidative stress, and this is one of the mechanisms that causes widespread endothelial dysfunction in most cardiovascular diseases and disorders. Hence attention has increasingly been paid to enhance mobilization and differentiation of EPCs for therapeutic purposes. The aim of this study was to investigate whether Icariin, a natural bioactive component known from traditional Chinese Medicine, can induce angiogenic differentiation and inhibit oxidative stress-induced cell dysfunction in bone marrow-derived EPCs (BM-EPCs), and, if so, through what mechanisms. We observed that treatment of BM-EPCs with Icariin significantly promoted cell migration and capillary tube formation, substantially abrogated hydrogen peroxide (H2 O2 )-induced apoptotic and autophagic programmed cell death that was linked to the reduced intracellular reactive oxygen species levels and restored mitochondrial membrane potential. Icariin downregulated endothelial nitric oxide synthase 3, as well as nicotinamide-adenine dinucleotide phosphate-oxidase expression upon H2 O2 induction. These antiapoptotic and antiautophagic effects of Icariin are possibly mediated by restoring the loss of mammalian target of rapamycin /p70S6K/4EBP1 phosphorylation as well as attenuation of ATF2 and ERK1/2 protein levels after H2 O2 treatment. In summary, favorable modulation of the angiogenesis and redox states in BM-EPCs make Icariin a promising proangiogenic agent both enhancing vasculogenesis and protecting against endothelial dysfunction.

Administered circulating microparticles derived from lung cancer patients markedly improved angiogenesis, blood flow and ischemic recovery in rat critical limb ischemia

BACKGROUND

We hypothesized that lung cancer patient's circulating microparticles (Lc-MPs) could promote angiogenesis, blood flow in ischemic zone and ischemic recovery in rat critical limb ischemia (CLI).

METHODS

To investigate the impact of MP therapy on reversing the setting of CLI, adult-male Sprague-Dawley rats (n=50) equally randomized into sham control (SC) (group 1), SC-Lc-MPs (1.0 x 10(7) particles) (group 2), CLI (group 3), CLI-Hs-MPs (MPs from healthy-subject) (group 4), and CLI-Lc-MPs (group 5) were sacrificed by post-CLI day-14.

RESULTS

In vitro study showed that Lc-MPs enhanced VEGFR2 expression, angiogenesis, nitric-oxide production, and endothelial cell proliferation (all p<0.005). By days 7 and 14, Laser Doppler showed significantly higher ischemic/normal blood-flow ratio in groups 1 and 2 compared with group 3, and was significantly higher in group 4 and further elevated in group 5 (p<0.0001). Numbers of small vessels and endothelial markers (CD31(+) and vWF(+) cells) and protein expressions (eNOS, CD31) exhibited a pattern identical to Lasre Doppler among the five groups (all p<0.001). Pro-angiogenic factors (VEGF, CXCR4, SDF-1α, HGF) at cellular and protein levels showed a significant step-wise increase from groups 1 and 2 to groups 3, 4, and 5 (all p<0.001). Protein expressions of fibrotic (Smad3, TGF-β) and apoptotic (mitochondrial Bax, cleaved caspase 3, and PARP) biomarkers displayed an opposite pattern compared to that of Laser Doppler, whereas the protein expressions of anti-fibrotic (Smad1/5, BMP-2) and anti-apoptotic (Bcl-2) biomarkers showed an identical pattern compared with that of Laser Doppler among groups 1 to 3, and 5 (all p<0.001).

CONCLUSION

Administration of Lc-MPs augmented angiogenesis and restored blood flow in a rat of CLI.

Microparticles as potential biomarkers of cardiovascular disease

Primary prevention of cardiovascular disease is a choice of great relevance because of its impact on health. Some biomarkers, such as microparticles derived from different cell populations, have been considered useful in the assessment of cardiovascular disease. Microparticles are released by the membrane structures of different cell types upon activation or apoptosis, and are present in the plasma of healthy individuals (in levels considered physiological) and in patients with different pathologies. Many studies have suggested an association between microparticles and different pathological conditions, mainly the relationship with the development of cardiovascular diseases. Moreover, the effects of different lipid-lowering therapies have been described in regard to measurement of microparticles. The studies are still controversial regarding the levels of microparticles that can be considered pathological. In addition, the methodologies used still vary, suggesting the need for standardization of the different protocols applied, aiming at using microparticles as biomarkers in clinical practice.

Angiogenic microvascular endothelial cells release microparticles rich in tissue factor that promotes postischemic collateral vessel formation

OBJECTIVE

Therapeutic angiogenesis is a promising strategy for treating ischemia. Our previous work showed that endogenous endothelial tissue factor (TF) expression induces intracrine signaling and switches-on angiogenesis in microvascular endothelial cells (mECs). We have hypothesized that activated mECs could exert a further paracrine regulation through the release of TF-rich microvascular endothelial microparticles (mEMPs) and induce neovascularization of ischemic tissues.

APPROACH AND RESULTS

Here, we describe for the first time that activated mECs are able to induce reparative neovascularization in ischemic zones by releasing TF-rich microparticles. We show in vitro and in vivo that mEMPs released by both wild-type and TF-upregulated-mECs induce angiogenesis and collateral vessel formation, whereas TF-poor mEMPs derived from TF-silenced mECs are not able to trigger angiogenesis. Isolated TF-bearing mEMPs delivered to nonperfused adductor muscles in a murine hindlimb ischemia model enhance collateral flow and capillary formation evidenced by MRI. TF-bearing mEMPs increase angiogenesis operating via paracrine regulation of neighboring endothelial cells, signaling through the β1-integrin pathway Rac1-ERK1/2-ETS1 and triggering CCL2 (chemokine [C-C motif] ligand 2) production to form new and competent mature neovessels.

CONCLUSIONS

These findings demonstrate that TF-rich mEMPs released by microvascular endothelial cells can overcome the consequences of arterial occlusion and tissue ischemia by promoting postischemic neovascularization and tissue reperfusion.

Levels of circulating microparticles in patients with chronic cardiorenal disease

AIM

Cardiac and renal diseases are common disorders that frequently coexist. We tested the hypothesis that the levels of circulating endothelial-derived apoptotic microparticles (EDA-MPs; CD31(＋)CD42b(-)AN(-)V(＋)) and platelet-derived apoptotic microparticles (PDA-MPs; CD31(＋)CD42b(＋)AN(-)V(＋)) are useful biomarkers for predicting the presence of cardiorenal disease (CRD).

METHODS

A total of 68 patients with chronic kidney disease (CKD) and angina pectoris (CKD-AP) undergoing cardiac catheterization were prospectively enrolled into group 1, 10 patients with coronary artery disease (CAD) without CKD were enrolled into group 2 (CAD(＋)CKD(-)) and 10 patients without CAD and CKD were enrolled into group 3 (CAD(-)CKD(-)).

RESULTS

The serum creatinine levels were significantly higher, whereas the estimated glomerular filtration rates (eGFRs) were significantly lower, in group 1 than in the other two groups (all p < 0.02). The circulating levels of EDA-MPs and PDA-MPs did not differ between the patients with and without CKD (all p > 0.2). However, the circulating levels of EDA-MPs and PDA-MPs were significantly higher in group 2 than in groups 1 and 3 (all p < 0.03). In addition, differences were noted in the circulating EDA-MP and PDA-MP levels between groups 1 and 3, although without statistical significance (all p > 0.09). Meanwhile, among the CKD patients, the subgroup analysis showed that the levels of MPs were significantly higher in those with CAD than in those without (all p=0.001), while a multivariate analysis demonstrated that CAD was the only factor independently predictive of high levels of circulating EDA-MPs and PDA-MPs (p=0.033).

CONCLUSIONS

The link with increased circulating levels of MPs is more consistent in patients with CAD than in those with CKD.

In vitro modeling of the neurovascular environment by coculturing adult human brain endothelial cells with human neural stem cells

Brain and vascular cells form a functionally integrated signalling network that is known as the neurovascular unit (NVU). The signalling (autocrine, paracrine and juxtacrine) between different elements of this unit, especially in humans, is difficult to disentangle in vivo. Developing representative in vitro models is therefore essential to better understand the cellular interactions that govern the neurovascular environment. We here describe a novel approach to assay these cellular interactions by combining a human adult cerebral microvascular endothelial cell line (hCMEC/D3) with a fetal ganglionic eminence-derived neural stem cell (hNSC) line. These cell lines provide abundant homogeneous populations of cells to produce a consistently reproducible in vitro model of endothelial morphogenesis and the ensuing NVU. Vasculature-like structures (VLS) interspersed with patches of differentiating neural cells only occurred when hNSCs were seeded onto a differentiated endothelium. These VLS emerged within 3 days of coculture and by day 6 were stabilizing. After 7 days of coculture, neuronal differentiation of hNSCs was increased 3-fold, but had no significant effect on astrocyte or oligodendrocyte differentiation. ZO1, a marker of adherens and tight junctions, was highly expressed in both undifferentiated and differentiated endothelial cells, but the adherens junction markers CD31 and VE-cadherin were significantly reduced in coculture by approximately 20%. A basement membrane, consisting of laminin, vitronectin, and collagen I and IV, separated the VLS from neural patches. This simple assay can assist in elucidating the cellular and molecular signaling involved in the formation of VLS, as well as the enhancement of neuronal differentiation through endothelial signaling.