Microparticles and cardiovascular diseases

Advances in the study of microparticles in diabetic retinopathy

Diabetic retinopathy (DR) is one of the common diabetic microangiopathies, which severely impairs vision in diabetic population. The underlying mechanisms regarding the development of DR are not fully understood, and there is a lack of biomarkers to guide clinical, assessment of disease progression. Recently researchers have found that microparticles (MP) and its bioactive molecules are involved in the development of DR. MP is widely distributed in the circulation and can exert autocrine and paracrine benefits in intercellular signalling, provide a catalytic platform for the thrombospondin complex to promote coagulation, and promote the accumulation of reactive oxygen species to cause endothelial damage. MP interacts with advanced glycosylation end products (AGE) and AGE receptor (RAGE) to activate inflammatory pathways. MP carries a variety of miRNAs that regulate the vascular endothelial growth factor generation pathway. MP has also been applied to the exploration of mesenchymal stromal cell replacement therapy to treat DR. In a word, MP provides new ideas for the study of DR. MP has emerged as a marker to assess the progression of DR. As a potential therapeutic target, MP also has considerable research value.

Dietary n-3 polyunsaturated fatty acids alter the number, fatty acid profile and coagulatory activity of circulating and platelet-derived extracellular vesicles: a randomized, controlled crossover trial

BACKGROUND

Extracellular vesicles (EVs) are proposed to play a role in the development of cardiovascular diseases (CVDs) and are considered emerging markers of CVDs. n-3 PUFAs are abundant in oily fish and fish oil and are reported to reduce CVD risk, but there has been little research to date examining the effects of n-3 PUFAs on the generation and function of EVs.

OBJECTIVES

We aimed to investigate the effects of fish oil supplementation on the number, generation, and function of EVs in subjects with moderate risk of CVDs.

METHODS

A total of 40 participants with moderate risk of CVDs were supplemented with capsules containing either fish oil (1.9 g/d n-3 PUFAs) or control oil (high-oleic safflower oil) for 12 wk in a randomized, double-blind, placebo-controlled crossover intervention study. The effects of fish oil supplementation on conventional CVD and thrombogenic risk markers were measured, along with the number and fatty acid composition of circulating and platelet-derived EVs (PDEVs). PDEV proteome profiles were evaluated, and their impact on coagulation was assessed using assays including fibrin clot formation, thrombin generation, fibrinolysis, and ex vivo thrombus formation.

RESULTS

n-3 PUFAs decreased the numbers of circulating EVs by 27%, doubled their n-3 PUFA content, and reduced their capacity to support thrombin generation by >20% in subjects at moderate risk of CVDs. EVs derived from n-3 PUFA-enriched platelets in vitro also resulted in lower thrombin generation, but did not alter thrombus formation in a whole blood ex vivo assay.

CONCLUSIONS

Dietary n-3 PUFAs alter the number, composition, and function of EVs, reducing their coagulatory activity. This study provides clear evidence that EVs support thrombin generation and that this EV-dependent thrombin generation is reduced by n-3 PUFAs, which has implications for prevention and treatment of thrombosis.

CLINICAL TRIAL REGISTRY

This trial was registered at clinicaltrials.gov as NCT03203512.

Update on Hemodialysis-Induced Multiorgan Ischemia: Brains and Beyond

Hemodialysis is a life-saving treatment for patients with kidney failure. However, patients requiring hemodialysis have a 10-20 times higher risk of cardiovascular morbidity and mortality than that of the general population. Patients encounter complications such as episodic intradialytic hypotension, abnormal perfusion to critical organs (heart, brain, liver, and kidney), and damage to vulnerable vascular beds. Recurrent conventional hemodialysis exposes patients to multiple episodes of circulatory stress, exacerbating and being aggravated by microvascular endothelial dysfunction. This promulgates progressive injury that leads to irreversible multiorgan injury and the well-documented higher incidence of cardiovascular disease and premature death. This review aims to examine the underlying pathophysiology of hemodialysis-related vascular injury and consider a range of therapeutic approaches to improving outcomes set within this evolved rubric.‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬.

Clinical significance of small extracellular vesicles in cholangiocarcinoma

Cholangiocarcinoma is an aggressive and heterogeneous malignancy originating from the bile duct epithelium. It is associated with poor prognosis and high mortality. The global incidence of cholangiocarcinoma is rising, and there is an urgent need for effective early diagnosis and treatment strategies to reduce the burden of this devastating tumor. Small extracellular vesicles, including exosomes and microparticles, are nanoscale vesicles formed by membranes that are released both normally and pathologically from cells, mediating the intercellular transfer of substances and information. Recent studies have demonstrated the involvement of small extracellular vesicles in numerous biological processes, as well as the proliferation, invasion, and metastasis of tumor cells. The present review summarizes the tumorigenic roles of small extracellular vesicles in the cholangiocarcinoma microenvironment. Owing to their unique composition, accessibility, and stability in biological fluids, small extracellular vesicles have emerged as ideal biomarkers for use in liquid biopsies for diagnosing and outcome prediction of cholangiocarcinoma. Specific tissue tropism, theoretical biocompatibility, low clearance, and strong biological barrier penetration of small extracellular vesicles make them suitable drug carriers for cancer therapy. Furthermore, the potential value of small extracellular vesicle-based therapies for cholangiocarcinoma is also reviewed.

Extracellular vesicles are a late marker of inflammation, hypercoagulability and COVID-19 severity

Exacerbated inflammation and coagulation are a hallmark of COVID-19 severity. Extracellular vesicles (EVs) are intercellular transmitters involved in inflammatory conditions, which are capable of triggering prothrombotic mechanisms. Since the release of EVs is potentially associated with COVID-19-induced coagulopathy, the aim of this study was to evaluate changes in inflammation- and hypercoagulability-related EVs during the first month after symptom onset and to determine whether they are associated with disease severity. Blood samples of patients with mild or severe forms of the disease were collected on three occasions: in the second, third and fourth weeks after symptom onset for the quantification by flow cytometry of CD41A (platelet glycoprotein IIb/IIIa), CD162 (PSGL-1), CD31 (PECAM-1) and CD142 cells (tissue factor). Analysis of variance (ANOVA) with repeated measures, Kruskal-Wallis and correlation tests were used. Eighty-five patients were enrolled, 71% of whom had mild disease. Seventeen uninfected individuals served as controls. Compared to controls, both mild and severe COVID-19 were associated with higher EV-CD31+, EV-CD41+ and EV-CD142+ levels. All EV levels were higher in severe than in mild COVID-19 only after the third week from symptom onset, as opposed to C-reactive protein and D-dimer levels, which were higher in severe than in mild COVID-19 earlier during disease progression. EV levels were also associated with C-reactive protein and D-dimer levels only after the third week of symptoms. In conclusion, EVs expressing CD41A, CD31, TF, and CD162 appear as late markers of COVID-19 severity. This finding may contribute to the understanding of the pathogenesis of acute and possibly long COVID-19.

Circulating microvesicles across a population with various degree of cardiovascular burden are associated with systolic blood pressure

Circulating microvesicles (MVs) have been studied in heterogeneous, divergent, and rather small patient populations with cardiovascular risk . Therefore, we measured endothelial (EMVs), platelet (PMVs) and erythrocyte (RMVs) MVs in patients with divergent cardiovascular risk. We then compared them to coronary artery disease (CAD) and healthy subjects and identified independent MVs' predictors. We enrolled consecutive patients from our Cardiology, Hypertension, Diabetic, Rheumatic, and Nephrology Outpatient Units with MVs measurements. Central blood pressure (BP) was measured by either applanation tonometry or Mobil-O-graph device, while MVs by a standardized flow cytometry protocol. We studied 369 participants with increased cardiovascular risk: 63 with high cardiovascular risk (47 diabetes mellitus type II/DM and 16 end-stage renal disease/ESRD), 92 with chronic inflammatory disorders and 73 with untreated essential hypertension/UEH. We further included 53 subjects with CAD and 87 otherwise healthy individuals. All MVs were lower in patients with increased cardiovascular risk compared to CAD, showing predictive value with high sensitivity and specificity. Furthermore, PMVs and EMVs were increased in patients with cardiovascular risk compared to healthy individuals. DM and ESRD patients had increased EMVs versus UEH and chronic inflammatory disorders. In the whole study population, RMVs were associated only with history of essential hypertension. In multivariate analysis, systolic BP predicted PMVs. Aage, systolic BP, and DM predicted EMVs. In a large population of patients with divergent cardiovascular risk, MVs are independently associated with systolic blood pressure.

Pravastatin reduces plasma levels of extracellular vesicles in pregnancies at high risk of term preeclampsia

Introduction: Elevated plasma levels of extracellular vesicles have been associated with impaired placentation, angiogenesis imbalance, intravascular inflammation, and endothelial dysfunction in women with preeclampsia, thus suggesting that circulating vesicles may be a good therapeutic target for the treatment of the disease. Recently, statins have been considered a potential treatment for the prevention of preeclampsia because of their pleiotropic effects, including the improvement of endothelial dysfunction and inhibition of inflammatory responses. However, the effects of these drugs on circulating vesicles concentration in women at risk of preeclampsia have not been established. Herein, we aimed to assess the effects of pravastatin on circulating extracellular vesicle generation in women at high risk of term preeclampsia. Methods: In a sample of 68 singleton pregnant women participating in the multicenter, double-blind, placebo-controlled STATIN trial (Nº EducraCT 2016-005206-19 ISRCTN), 35 women received a placebo and 33 women received a 20 mg/day dose of pravastatin for approximately 3 weeks (from 35 to 37 weeks of gestation until delivery). Large extracellular vesicles were characterized and quantified by flow cytometry using annexin V and cell-specific antibodies directed against platelet, endothelial, leukocyte, and syncytiotrophoblast cell surface markers. Results: In women who received the placebo, a significant increase in the plasma levels of large extracellular vesicles from platelets (34%, p < 0.01), leukocytes (33%, p < 0.01), monocytes (60%, p < 0.01), endothelial cells (40%, p < 0.05), and syncytiotrophoblast cells (22%, p < 0.05) were observed. However, treatment with pravastatin significantly reduced the plasma levels of large extracellular vesicles from platelets (42%, p < 0.001), leukocytes (25%, p < 0.001), monocytes (61%, p < 0.001), endothelial cells (69%, p < 0.001), activated endothelial cells (55%, p < 0.001), and syncytiotrophoblast cells (44%, p < 0.001). Discussion: These results indicate that pravastatin reduces the levels of activated cell-derived membrane vesicles from the maternal vasculature, blood, and placental syncytiotrophoblast of women at high risk of term preeclampsia, suggesting that this statin may be beneficial in reducing endothelial dysfunction and pro-inflammatory and pro-coagulatory state characteristics of the disease.

Grafted dinuclear zinc complexes for selective recognition of phosphatidylserine: Application to the capture of extracellular membrane microvesicles

Microvesicles (MVs) are key markers in human body fluids that reflect cellular activation related to diseases as thrombosis. These MVs display phosphatidylserine at the outer leaflet of their plasma membrane as specific recognition moieties. The work reported in this manuscript focuses on the development of an original method where MVs are captured by bimetallic zinc complexes. A set of ligands have been synthetized based on a phenol spacer bearing in para position an amine group appended to a short or a longer alkyl chain (for grafting on surface) and bis(dipicolylamine) arms in ortho position (for zinc coordination). The corresponding dibridged zinc phenoxido and hydroxido complexes have been prepared in acetronitrile in presence of triethylamine and characterized by several spectroscopic techniques. The pH-driven interconversion studies for both complexes in H₂O:DMSO (70:30) evidence that at physiologic pH the main species are mono-bridged by the phenoxido spacer. An X-Ray structure obtained from complex 2 (based on the ligand with the amine group on the short chain) in aqueous medium confirms the presence of a mono-bridged complex. Then, the complexes have been used for interaction studies with short-chain phospholipids. Both have established the selective recognition of the anionic phosphatidylserine model versus zwitterionic phospholipids (in solution by ³¹P NMR and after immobilization on solid support by surface plasmon resonance (SPR)). Moreover, both complexes have also demonstrated their ability to capture MVs isolated from human plasma. These complexes are thus promising candidates for MVs probing by a new approach based on coordination chemistry.

An injectable conductive hydrogel restores electrical transmission at myocardial infarct site to preserve cardiac function and enhance repair

Myocardial infarction (MI) leads to massive cardiomyocyte death and deposition of collagen fibers. This fibrous tissue disrupts electrical signaling in the myocardium, leading to cardiac systolic and diastolic dysfunction, as well as arrhythmias. Conductive hydrogels are a promising therapeutic strategy for MI. Here, we prepared a highly water-soluble conductive material (GP) by grafting polypyrrole (PPy) onto non-conductive gelatin. This component was added to the gel system formed by the Schiff base reaction between oxidized xanthan gum (OXG) and gelatin to construct an injectable conductive hydrogel. The prepared self-healing OGGP3 (3 wt% GP) hydrogel had good biocompatibility, elastic modulus, and electrical conductivity that matched the natural heart. The prepared biomaterials were injected into the rat myocardial scar tissue 2 days after MI. We found that the cardiac function of the rats treated with OGGP3 was improved, making it more difficult to induce arrhythmias. The electrical resistivity of myocardial fibrous tissue was reduced, and the conduction velocity of myocardial tissue was increased. Histological analysis showed reduced infarct size, increased left ventricular wall thickness, increased vessel density, and decreased inflammatory response in the infarcted area. Our findings clearly demonstrate that the OGGP3 hydrogel attenuates ventricular remodeling and inhibits infarct dilation, thus showing its potential for the treatment of MI.

•

An injectable self-healing conductive hydrogel was synthesized for the treatment of myocardial infarction (MI).

•

The OGGP3 hydrogel had elastic modulus (20.77 kPa) and conductivity (5.52 × 10⁻⁴ S/cm) that matched the natural heart.

•

The hydrogel could protect cardiac function, reduce arrhythmia susceptibility and the resistivity of cardiac scar tissue.

•

The hydrogel could increase left ventricular wall thickness, reduce infarct size and cardiac fibrosis in the infarcted area.

•

The hydrogel could promote the expression level of cardiac-specific markers, induce angiogenesis, and reduce inflammation.

Microvesicles with mitochondrial content are increased in patients with sepsis and associated with inflammatory responses

BACKGROUND

Endothelial activation plays an important role in sepsis-mediated inflammation, but the triggering factors have not been fully elucidated. Microvesicles carrying mitochondrial content (mitoMVs) have been implicated in several diseases and shown to induce endothelial activation.

AIM

To explore whether mitoMVs constitute a subset of MVs isolated from plasma of patients with sepsis and contribute to endothelial activation.

METHODS

MVs were isolated from human plasma and characterized by confocal microscopy and flow cytometry. Proinflammatory cytokines, including interleukin (IL)-6, IL-8 and tumour necrosis factor (TNF)-α, and soluble vascular cell adhesion molecule (sVCAM)-1 were detected by ELISA. Human umbilical vein endothelial cells (HUVECs) were stimulated with the circulating MVs to evaluate their effect on endothelial activation.

RESULTS

MitoMVs were observed in plasma from patients with sepsis. Compared with those in healthy controls, expression of MVs, mitoMVs, proinflammatory cytokines and sVCAM-1 was increased. The number of mitoMVs was positively associated with TNF-α and sVCAM-1. In vitro, compared with MVs isolated from the plasma of healthy controls, MVs isolated from the plasma of patients with sepsis induced expression of OAS2, RSAD2, and CXCL10 in HUVECs. MitoMVs were taken up by HUVECs, and sonication of MVs significantly reduced the uptake of mitoMVs by HUVECs and expression of the above three type I IFN-dependent genes.

CONCLUSION

MitoMVs are increased in the plasma of patients with sepsis, which induces elevated expression of type I IFN-dependent genes. This suggests that circulating mitoMVs activate the type I IFN signalling pathway in endothelial cells and lead to endothelial activation.

Increased circulating microparticles contribute to severe infection and adverse outcomes of COVID-19 in patients with diabetes

Patients with diabetes infected with COVID-19 have greater mortality than those without comorbidities, but the underlying mechanisms remain unknown. This study aims to identify the mechanistic interactions between diabetes and severe COVID-19. Microparticles (MPs), the cell membrane-derived vesicles released on cell activation, are largely increased in patients with diabetes. To date, many mechanisms have been postulated for increased severity of COVID-19 in patients with underlying conditions, but the contributions of excessive MPs in patients with diabetes have been overlooked. This study characterizes plasma MPs from normal human subjects and patients with type 2 diabetes in terms of amount, cell origins, surface adhesive properties, ACE2 expression, spike protein binding capacity, and their roles in SARS-CoV-2 infection. Results showed that over 90% of plasma MPs express ACE2 that binds the spike protein of SARS-CoV-2. MPs in patients with diabetes increase 13-fold in quantity and 11-fold in adhesiveness when compared with normal subjects. Perfusion of human plasma with pseudo-typed SARS-CoV-2 virus or spike protein-bound MPs into human endothelial cell-formed microvessels-on-a chip demonstrated that MPs from patients with diabetes, not normal subjects, interact with endothelium and carry SARS-CoV-2 into cells through endocytosis, providing additional virus entry pathways and enhanced infection. Results also showed a large percentage of platelet-derived tissue factor-bearing MPs in diabetic plasma, which could contribute to thrombotic complications with SARS-CoV-2 infection. This study reveals a dual role of diabetic MPs in promoting SARS-CoV-2 entry and propagating vascular inflammation. These findings provide novel mechanistic insight into the high prevalence of COVID-19 in patients with diabetes and their propensity to develop severe vascular complications.NEW & NOTEWORTHY This study provides the first evidence that over 90% of human plasma microparticles express ACE2 that binds SARS-CoV-2 S protein with high affinity. Thus, the highly elevated adhesive circulating microparticles identified in patients with diabetes not only have greater SARS-CoV-2 binding capacity but also enable additional viral entry through virus-bound microparticle-endothelium interactions and enhanced infection. These findings reveal a novel mechanistic insight into the adverse outcomes of COVID-19 in patients with diabetes.

Inflammatory Response and Immune Regulation in Brain-Heart Interaction after Stroke

Cerebrocardiac syndrome (CCS) is one of the secondary myocardial injuries after stroke. Cerebrocardiac syndrome may result in a poor prognosis with high mortality. Understanding the mechanism of the brain-heart interaction may be crucial for clinical treatment of pathological changes in CCS. Accumulating evidence suggests that the inflammatory response is involved in the brain-heart interaction after stroke. Systemic inflammatory response syndrome (SIRS) evoked by stroke may injure myocardial cells directly, in which the interplay between inflammatory response, oxidative stress, cardiac sympathetic/parasympathetic dysfunction, and splenic immunoregulation may be also the key pathophysiology factor. This review article summarizes the current understanding of inflammatory response and immune regulation in brain-heart interaction after stroke.

Circulating microparticles are associated with plaque burden and cause eNOS uncoupling in patients with carotid atherosclerosis

Aims: The study aimed to evaluate the correlation of different microparticle (MP) phenotypes with plaque burden and their diagnostic value and preliminarily explore the role of MPs in atherosclerosis (AS).

Methods: Carotid intima-media thickness (CIMT) and maximal plaque area in 23 patients with carotid atherosclerosis (CAS) and 22 healthy subjects were measured by ultrasound. Transmission electron microscopy, nanoparticle tracking analysis and western blot were used to identify MPs. Flow cytometry assay measured absolute number of MPs, and receiver operating characteristic (ROC) analysis was used to assess the relationship between plaque burden and MPs. To study the preliminary mechanism of MPs in AS, MPs were administered to 32 male Kunming mice, which were randomly divided into control, CAS, healthy, and tetrahydrobiopterin (BH4) groups. Hematoxylin-eosin staining, immunohistochemistry staining, and Western blot were adopted to detect relevant indexes 24 h after the injection.

Results: The plasma levels of CD45+ leukocyte-derived microparticle (LMP), CD11a+ LMP, CD11a+/CD45+ LMP, and CD31+/CD42b+ platelet-derived microparticle (PMP) in CAS patients were significantly higher than those in healthy subjects, and were positively correlated with the maximal plaque area. Moreover, the levels of CD11a+ LMP, CD11a+/CD45+ LMP were also positively correlated with CIMT. The area under the ROC curve of the four MPs was 0.689, 0.747, 0.741, and 0.701, respectively. Compared with healthy subjects, MPs from CAS patients resulted in a significantly lower expression of endothelial nitric oxide synthase (eNOS) dimer/monomer, and BH4 could improve eNOS uncoupling. Moreover, the level of VCAM-1 in intima in the CAS group was significantly higher than in the other three groups.

Conclusion: CD11a+ LMP and CD11a+/CD45+ LMP might be potential biomarkers for CAS prediction. BH4-related eNOS uncoupling occurs in CAS patients, and circulating MPs from them lead to endothelial dysfunction through eNOS uncoupling.

Exploration of cerebral vasospasm from the perspective of microparticles

Cerebral vasospasm is a frequently encountered clinical problem, especially in patients with traumatic brain injury and subarachnoid hemorrhage. Continued cerebral vasospasm can cause cerebral ischemia, even infarction and delayed ischemic neurologic deficits. It significantly affects the course of the disease and the outcome of the patient. However, the underlying mechanism of cerebral vasospasm is still unclear. Recently, increasing studies focus on the pathogenic mechanism of microparticles. It has been found that microparticles have a non-negligible role in promoting vasospasm. This research aims to summarize the dynamics of microparticles in vivo and identify a causal role of microparticles in the occurrence and development of cerebral vasospasm. We found that these various microparticles showed dynamic characteristics in body fluids and directly or indirectly affect the cerebral vasospasm or prompt it. Due to the different materials carried by microparticles from different cells, there are also differences in the mechanisms that lead to abnormal vasomotor. We suggest that microparticle scavengers might be a promising therapeutic target against microparticles associated complications.

Extracellular Vesicles, Inflammation, and Cardiovascular Disease

Cardiovascular disease is a leading cause of death worldwide. The underlying mechanisms of most cardiovascular disorders involve innate and adaptive immune responses, and extracellular vesicles are implicated in both. In this review, we describe the mechanistic role of extracellular vesicles at the intersection of inflammatory processes and cardiovascular disease. Our discussion focuses on atherosclerosis, myocardial ischemia and ischemic heart disease, heart failure, aortic aneurysms, and valvular pathology.

Extracellular Vesicles in Atrial Fibrillation—State of the Art

Extracellular vesicles are particles released from cells and delimited by a lipid bilayer. They have been widely studied, including extensive investigation in cardiovascular diseases. Many scientists have explored their role in atrial fibrillation. Patients suffering from atrial fibrillation have been evidenced to present altered levels of these particles as well as changed amounts of their contents such as micro-ribonucleic acids (miRs). Although many observations have been made so far, a large randomized clinical trial is needed to assess the previous findings. This review aims to thoroughly summarize current research regarding extracellular vesicles in atrial fibrillation.

The Role of Cell Derived Microparticles in Cardiovascular Diseases: Current Concepts

Abstract:

Cardiovascular disease remains the main cause of human morbidity and mortality in the developed countries. Microparticles (MPs) are small vesicles originating from the cell membrane as a result of various stimuli and particularly of biological processes that constitute the pathophysiology of atherosclerosis, such as endothelial damage. They form vesicles that can transfer various molecules and signals to remote target cells without direct cell to cell interaction. Circulating microparticles have been associated with cardiovascular diseases. Therefore, many studies have been designed to further investigate the role of microparticles as biomarkers for diagnosis, prognosis, and disease monitoring. To this concept the pro-thrombotic and atherogenic potential of platelets and endothelial derived MPs has gain research interest especially concerning accelerate atherosclerosis and acute coronary syndrome triggering and prognosis. MPs especially of endothelial origin have been investigated in different clinical scenarios of heart failure and in association of left ventricular loading conditions. Finally, most cardiovascular risk factors present unique patterns of circulating MPs population, highlighting their pathophysiologic link to cardiovascular disease progression. In this review article we present a synopsis of the biogenesis and characteristics of microparticles, as well as the most recent data concerning their implication in the cardiovascular settings.

Angiogenesis, Metabolism, Endothelial and Platelet Markers in Diabetes and Cardiovascular Disease

Introduction: Diabetes is a leading risk factor for cardiovascular disease (CVD), the pathophysiology of both being linked to metabolic, endothelial, renal, angiogenic and platelet abnormalities. We hypothesised that abnormalities in these systems are more adverse in those whose CVD is compounded by diabetes, compared to those with diabetes or CVD alone.

Materials and methods: Serum or plasma from 66 patients with diabetes alone, 76 with CVD alone, and 70 with both diabetes and CVD i.e. diabetic cardiovascular disease, was probed for markers of angiogenesis [angiopoietin 1 and 2, vascular endothelial growth factor (VEGF) and endoglin], metabolic [soluble receptor for advanced glycation products (sRAGE), leptin, lipocalin-2, interleukin-8, and cystatin-C], the endothelium (von Willebrand factor, endothelial microparticles and soluble E selectin)], and the platelet (platelet microparticles and soluble P selectin) by ELISA, Luminex or flow cytometry.

Results: VEGF (p = 0.04), von Willebrand factor (p = 0.001) and endothelial microparticles (p = 0.042) were all higher in diabetic cardiovascular disease than in diabetes alone and cardiovascular disease alone. Soluble E selectin was higher in diabetic cardiovascular disease than in diabetes alone (p = 0.045), whilst cystatin-C (p = 0.004) and soluble P selectin (p < 0.001) were higher in diabetes and diabetic cardiovascular disease than in cardiovascular disease alone. There were no differences in angiopoietin 1 or 2, endoglin, sRAGE, leptin, lipocalin-2, or interleukin-8.

Conclusion: Angiopoietin 1 or 2, endoglin, sRAGE, leptin, lipocalin-2, interleukin-8, and cystatin-c cannot differentiate diabetes from cardiovascular disease, or both conditions combined. Our data point to a more adverse endothelial (von Willebrand factor, endothelial microparticles), and angiogenic profile (VEGF) in those with diabetic cardiovascular disease, supporting the view that this group should be targeted more aggressively.

Oxygen saturation in retinal vessels and their correlation with endothelial microparticles in diabetes mellitus and/or cardiovascular disease

PURPOSE

Retinal oxygen supply is a critical requirement in ocular function, and when inadequate can lead to retinopathy. Endothelial dysfunction is a leading pathophysiology in diabetes and cardiovascular disease and may be assessed by endothelial microparticles (EMPs). We hypothesised links between retinal vessel oxygenation and EMPs, expecting these indices to be more adverse in those with both DM and CVD.

METHODS

Plasma from 34 patients with diabetes mellitus alone (DM), 40 with cardiovascular disease (CVD) alone and 36 with DM plus CVD was probed for EMPs by flow cytometry, but also for vascular markers soluble E-selectin (sEsel) and von Willebrand factor (vWf) (both ELISA). Retinal vessel fractal dimension, lacunarity, calibres and oxygen saturation were assessed from monochromatic and dual wavelength imaging respectively, intra-ocular pressure by was measured by rebound tonometry (I-CARE).

RESULTS

There was no difference in oxygenation (arterial p = 0.725, venous p = 0.264, arterio-venous difference 0.375) between the groups, but there were differences in EMPs (p = 0.049), vWf (p = 0.004) and sEsel (p = 0.032). In the entire cohort, and in diabetes alone, EMPs correlated with venous oxygenation (r = 0.24, p = 0.009 and r = 0.43, p = 0.011 respectively), while in DM + CVD, sEsel correlated with venous oxygenation (r = 0.55, p = 0.002) and with the arterial-venous difference (r = -0.63, p = 0.001). In multivariate regression analysis of vascular markers against retinal oximetry indices in the entire group, EMPs were positively linked to venous oxygenation (p = 0.037).

CONCLUSIONS

Despite differences in systemic markers of vascular function between DM, CVD and DM + CVD, there was no difference in arterial or venous retinal oxygenation, or their difference. However, EMPs were linked to venous oximetry, and may provide further insight into the mechanisms underlying diabetes and diabetic retinopathy.

Role of Circulating Microparticles in Type 2 Diabetes Mellitus: Implications for Pathological Clotting

Type 2 diabetes mellitus (T2DM) is a multifactorial chronic metabolic disease characterized by chronic hyperglycemia due to insulin resistance and a deficiency in insulin secretion. The global diabetes pandemic relates primarily to T2DM, which is the most prevalent form of diabetes, accounting for over 90% of all cases. Chronic low-grade inflammation, triggered by numerous risk factors, and the chronic activation of the immune system are prominent features of T2DM. Here we highlight the role of blood cells (platelets, and red and white blood cells) and vascular endothelial cells as drivers of systemic inflammation in T2DM. In addition, we discuss the role of microparticles (MPs) in systemic inflammation and hypercoagulation. Although once seen as inert by-products of cell activation or destruction, MPs are now considered to be a disseminated storage pool of bioactive effectors of thrombosis, inflammation, and vascular function. They have been identified to circulate at elevated levels in the bloodstream of individuals with increased risk of atherothrombosis or cardiovascular disease, two significant hallmark conditions of T2DM. There is also general evidence that MPs activate blood cells, express proinflammatory and coagulant effects, interact directly with cell receptors, and transfer biological material. MPs are considered major players in the pathogenesis of many systemic inflammatory diseases and may be potentially useful biomarkers of disease activity and may not only be of prognostic value but may act as novel therapeutic targets.

The Dynamic of Extracellular Vesicles in Patients With Subacute Stroke: Results of the "Biomarkers and Perfusion-Training-Induced Changes After Stroke" (BAPTISe) Study

Objective: Extracellular vesicles (EV) are sub-1 μm bilayer lipid coated particles and have been shown play a role in long-term cardiovascular outcome after ischemic stroke. However, the dynamic change of EV after stroke and their implications for functional outcome have not yet been elucidated. Methods: Serial blood samples from 110 subacute ischemic stroke patients enrolled in the prospective BAPTISe study were analyzed. All patients participated in the PHYS-STROKE trial and received 4-week aerobic training or relaxation sessions. Levels of endothelial-derived (EnV: Annexin V+, CD45-, CD41-, CD31+/CD144+/CD146+), leukocyte-derived (LV: Annexin V+, CD45+, CD41-), monocytic-derived (MoV: Annexin V+, CD41-, CD14+), neuronal-derived (NV: Annexin V+, CD41-, CD45-, CD31-, CD144-, CD146-, CD56+/CD171+/CD271+), and platelet-derived (PV: Annexin V+, CD41+) EV were assessed via fluorescence-activated cell sorting before and after the trial intervention. The levels of EV at baseline were dichotomized at the 75th percentile, with the EV levels at baseline above the 75th percentile classified as "high" otherwise as "low." The dynamic of EV was classified based on the difference between baseline and post intervention, defining increases above the 75th percentile as "high increase" otherwise as "low increase." Associations of baseline levels and change in EV concentrations with Barthel Index (BI) and cardiovascular events in the first 6 months post-stroke were analyzed using mixed model regression analyses and cox regression. Results: Both before and after intervention PV formed the largest population of vesicles followed by NV and EnV. In mixed-model regression analyses, low NV [-8.57 (95% CI -15.53 to -1.57)] and low PV [-6.97 (95% CI -13.92 to -0.01)] at baseline were associated with lower BI in the first 6 months post-stroke. Patients with low increase in NV [8.69 (95% CI 2.08-15.34)] and LV [6.82 (95% CI 0.25-13.4)] were associated with reduced BI in the first 6 months post-stroke. Neither baseline vesicles nor their dynamic were associated with recurrent cardiovascular events. Conclusion: This is the first report analyzing the concentration and the dynamic of EV regarding associations with functional outcome in patients with subacute stroke. Lower levels of PV and NV at baseline were associated with a worse functional outcome in the first 6 months post-stroke. Furthermore, an increase in NV and LV over time was associated with worse BI in the first 6 months post-stroke. Further investigation of the relationship between EV and their dynamic with functional outcome post-stroke are warranted. Clinical Trial Registration: clinicaltrials.gov/, identifier: NCT01954797.

Effects of modified-Paleo and moderate-carbohydrate diets on body composition, serum levels of hepatokines and adipocytokines, and flow cytometric analysis of endothelial microparticles in adults with metabolic syndrome: a study protocol for a randomized clinical trial

Background

Metabolic syndrome is a combination of metabolic risk factors causing a pathological condition that increases the risk of non-communicable diseases, such as diabetes and cardiovascular diseases. A variety of dietary approaches have been examined to halt this rapid trend; however, the effects of modified-Paleo diet and medium-carbohydrate diet on inflammation, adipokines, hepatokines, and the profile of endothelial microparticles in individuals with metabolic syndrome have not been investigated in detail. The present study is designed to examine the effect of modified-Paleo and moderate-carbohydrate diet with two delivery modes: “fixed diet plan” vs “calorie counting” on weight, body composition, serum levels of some hepatokines and adipocytokines, and flow cytometric analysis of endothelial microparticles in adults with metabolic syndrome.

Methods

Eighty metabolic syndrome patients will be recruited in this study. They will be randomly allocated to one of the following 4 groups: (1) receiving a modified-Paleo diet with calorie counting, (2) receiving a modified-Paleo diet with a fixed diet plan, (3) receiving a medium-carbohydrate diet with calorie counting, and (4) receiving a medium-carbohydrate diet with a fixed diet plan for 10 weeks. Weight, height, waist circumference, and body composition will be assessed at the study baseline and at the end of the trial. Serum insulin, asprosin, chemerin, FGF-21, CTRP-1, PYY, ghrelin, plasma EMPs (CD31+/CD42b− and CD144+/CD42b−), lipid profile, glycemic indices, hs-CRP, leptin, vitamin C, creatinine and satiety, hunger, fullness, and desire to eat (via visual analog scales) will be measured at the study baseline and at the end of the trial. Insulin resistance and insulin sensitivity will be determined using the HOMA-IR and QUICKI equations.

Discussion

To the best of our knowledge, this is the first randomized controlled trial that will determine the effect of modified-Paleo and moderate-carbohydrate diet on weight, body composition, serum levels of some hepatokines and adipocytokines, and the profile of EMPs in adults with metabolic syndrome. Moreover, the effects of different diet delivery modes, including “fixed diet plan” and “calorie counting” will also be analyzed. The results of this trial can provide clinical witnesses on the effectiveness of carbohydrate-restricted diets in ameliorating metabolic status and prevent the development of chronic diseases.

Trial registration

Iranian Registry of Clinical Trials IRCT2016121925267N4. Registered on 26 July 2017

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05612-y.

Imbalance between the circulating endothelium-derived apoptotic microparticles and the endothelial colony-forming units of progenitor cells in patients undergoing diagnostic coronary angiography

PURPOSE

The involvement of the circulating endothelium-derived microparticles (EMPs) and the endothelial progenitor cells (EPCs) has been shown in the pathogenesis of coronary artery disease (CAD). The current study aimed to explore whether the Friesinger index is associated with the levels of the apoptotic CD144+/CD31+/annexin V+ ​EMPs and the number of endothelial colony-forming units of progenitor cells in patients undergoing coronary angiography.

PATIENTS AND METHODS

Fifty-seven patients with a median age of 62 years (range: 48-84 years) were enrolled. Quantification of the apoptotic CD144⁺/CD31⁺/annexin V⁺ EMPs was performed by flow cytometry. The number of endothelial colony-forming units defined by CFU-Hill was assessed by cell culture.

RESULTS

There was a positive correlation between the Friesinger index and the circulating levels of the apoptotic CD144⁺/CD31⁺/annexin V⁺ EMPs (rho=0.817, p<0.001), whereas a negative correlation was found with the number of CFU-Hill (rho ​= ​- 0.649, p<0.001). Multivariable logistic analysis showed that the risk of having moderate/severe CAD was five times greater among male patients (OR:5.32; 95% CI: 1.19 - 16.33; p=0.038) and almost one and a half times higher among those with a higher level of apoptotic CD144⁺/CD31⁺/annexin V⁺ EMPs (OR:1.74; 95% CI: 1.23 - 2.28; p=0.001). Finally, the circulating levels of apoptotic EMPs labelled for CD144⁺/CD31⁺/annexin V⁺ presented a good discrimination of moderate/severe CAD, with an AUC of 0.85 (95% CI ​= ​0.74 - 0.96; p< 0.001).

CONCLUSIONS

Moderate or severe CAD is associated with increased levels of apoptotic EMPs and reduced EPC colony-forming capacity, increasing the occurrence of endothelial injuries.

Circulating endothelial microparticles: a promising biomarker of acute kidney injury after cardiac surgery with cardiopulmonary bypass

Background

Current diagnostic strategies for acute kidney injury (AKI) after cardiac surgery with cardiopulmonary bypass (CPB) are nonspecific and limited. Previously, we demonstrated that circulating microparticles (MPs) in patients with valve heart disease (VHD) and congenital heart diseases (CHD) induce endothelial dysfunction and neutrophil chemotaxis, which may result in kidney injury. We also found that circulating MPs increase after cardiac surgery with CPB and are related to cardiac function. However, the relationship between circulating MPs and AKI after CPB is unknown.

Methods

Eighty-five patients undergoing cardiac surgery with CPB were enrolled. Patients were divided into AKI and non-AKI groups based on the serum creatinine levels at 12 h and 3 d post-CPB. Circulating MPs were isolated from plasma, and their levels including its subtypes were detected by flow cytometer. Independent risk factors for the CPB-associated AKI (CPB-AKI) were determined by multivariate logistic regression analysis. Receiver operating characteristic (ROC) analysis was used to measure the prognostic potential of CPB-AKI.

Results

The morbidity of AKI at 12 h and 3 d after cardiac surgery with CPB was 40% and 31.76%, respectively. The concentrations of total MPs and platelet-derived MPs (PMP) remained unchanged at 12 h and then increased at 3 d post-CPB, while that of endothelial-derived MPs (EMP) increased at both time points. In patients with AKI, PMP and EMP were elevated compared with the patients without AKI. However, no significant change was detected on monocyte-derived MPs (MMP) at 12 h and 3 d post-CPB. The logistic regression analysis showed that EMP was the independent risk factor for AKI both at 12 h and 3 d post-CPB. The area under ROC for the concentrations of EMP at 12 h and 3 d post-CPB was 0.86 and 0.91, with the specificity up to 0.88 and 0.91, respectively.

Conclusions

Circulating EMP may serve as a potential biomarker of AKI after cardiac surgery with CPB.

Regulation of Nrf2 signaling pathway in heart failure: Role of extracellular vesicles and non-coding RNAs

The balance between pro- and antioxidant molecules has been established as an important driving force in the pathogenesis of cardiovascular disease. Chronic heart failure is associated with oxidative stress in the myocardium and globally. Redox balance in the heart and brain is controlled, in part, by antioxidant proteins regulated by the transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2), which is reduced in the heart failure state. Nrf2 can, in turn, be regulated by a variety of mechanisms including circulating microRNAs (miRNAs) encapsulated in extracellular vesicles (EVs) derived from multiple cell types in the heart. Here, we review the role of the Nrf2 and antioxidant enzyme signaling pathway in mediating redox balance in the myocardium and the brain in the heart failure state. This review focuses on Nrf2 and antioxidant protein regulation in the heart and brain by miRNA-enriched EVs in the setting of heart failure. We discuss EV-mediated intra- and inter-organ communications especially, communication between the heart and brain via an EV pathway that mediates cardiac function and sympatho-excitation in heart failure. Importantly, we speculate how engineered EVs with specific miRNAs or antagomirs may be used in a therapeutic manner in heart failure.

CD36+/CD61+ Microparticles Correlate with the Risk of Percutaneous Cardiac Interventions in Coronary Artery Disease Patients and the Effects of Ticagrelor

PURPOSE

The CD36 scavenger receptor is a mediator of both atherogenesis and thrombosis. We aimed to investigate the prognostic value of CD36+ microparticles (MPs) released from platelets for cardiovascular event presentation in coronary artery disease (CAD) patients and the effects of different antiplatelet drugs on MPs.

METHODS

A total of 101 aspirin-treated CAD patients, who were planned to undergo coronary angiography (CAG), were randomized to either a standard clopidogrel regimen or ticagrelor treatment. Total Annexin V-(AV)+ MPs, CD61+/AV+ MPs, and CD36+/CD61+/AV+ MPs were quantified by flow cytometry at baseline, before and immediately after the operation. The ADP-induced platelet inhibition rate was measured by thromboelastogram (TEG) examination 1 h before the operation.

RESULTS

The baseline levels of CD36+/CD61+/AV+ MPs were significantly increased in percutaneous coronary intervention (PCI) patients (n = 52) compared to no-PCI patients (n = 49) (p < 0.05). A ROC-curve clustered model for CD36+/CD61+/AV+ MPs at baseline predicted an increased risk of PCI [p = 0.009, AUC = 0.761 (95%CI: 0.601 to 0.922)]. Moreover, TEG examination showed that the preoperative proportion of CD36+/CD61+/AV+ MPs was significantly negatively correlated with R time and K time (r = - 0.236, p = 00.026; r = - 0.288, p = 0.006), and positively correlated with MA_ADP (r = 0.226, p = 0.045). Subgroup analysis of PCI group showed that the platelet inhibition rate of ticagrelor was significantly higher (66.05% ± 28.76% vs.31.01% ± 27.33%, p < 0.001), and the number of AV+ MPs, CD61+/AV+ MPs, and CD36+/CD61+/AV+ MPs before the operation was significantly lower than clopidogrel (p < 0.05, all).

CONCLUSION

The high levels of CD36+ MPs derived from activated platelets are related to an increased risk of PCI in CAD patients. Ticagrelor significantly reduced the number of CD61+/AV+ MPs and CD36+/CD61+/AV+ MPs. This trial registration number is ChiCTR1800014908 and the date of registration is 2018.05.01.

A study of endothelial and platelet microvesicles across different hypertension phenotypes

Rather than being mere biomarkers reflecting generalized vascular injury, endothelial- (EMVs) and platelet-derived (PMVs) microvesicles have emerged as potent regulators of intercellular communication with significant biologic effects in vascular homeostasis and several pathophysiological responses including inflammation and thrombosis. So far, studies in hypertension are scarce, whereas no studies exist in masked hypertension (MH). We measured EMVs and PMVs in untreated, newly diagnosed hypertensives (HTs) and MHs compared to normotensive controls (NTs), and associated them with various cardiovascular risk factors. Sustained hypertension (SHT) and MH were defined according to standard blood pressure (BP) criteria. All HTs were free of cardiovascular disease and medications. Microvesicles' quantitation and detection were performed by flow cytometry by using cell-specific antibodies and corresponding isotypes (anti-CD105 and anti-CD144 for EMVs, anti-CD42a for PMVs, and Annexin V-fluorescein isothiocyanate for all microvesicles). In this study, we included 59 HTs (44 SHTs and 15 MHs) and 27 NTs. HTs had significantly elevated EMVs (p = 0.004), but not PMVs compared to NTs. MHs had significantly elevated EMVs compared to NTs (p = 0.012) but not compared to SHTs. Furthermore, EMVs significantly correlated with ambulatory (r = 0.214-0.284), central BP (r = 0.247-0.262), and total vascular resistance (r = 0.327-0.361). EMVs are increased not only in SHTs but also in MHs, a hypertension phenotype with a cardiovascular risk close to SHT. EMVs have emerged as active contributors to thromboinflammation and vascular damage and may explain, in part, the adverse cardiovascular profile of SHTs and MHs.

Analysis of Circulating Microvesicles Levels and Effects of Associated Factors in Elderly Patients With Obstructive Sleep Apnea

Background: The incidence of obstructive sleep apnea (OSA) in the elderly is high, and the disorder is associated with a variety of chronic diseases. Microvesicles (MVs) are extracellular vesicles secreted by various cells during stimulation or apoptosis that play an important role in the pathogenesis of OSA. However, concentrations of circulating MVs in elderly patients with OSA remain unclear.

Methods: Patients aged >60 years old were recruited and underwent polysomnography. Circulating plasma MV concentrations, including annexin V⁺MVs, endothelial MVs (EMVs), platelet MVs (PMVs), and leukocyte MVs (LMVs) levels, were measured using a flow cytometer with different labeling methods. Potential factors affecting the concentration of circulating MVs in elderly patients with OSA were determined via Spearman's correlation and multiple linear regression analysis.

Results: Levels of circulating MVs, including both single- (annexin V⁺MVs, CD144⁺EMVs, CD41a⁺PMVs, and CD45⁺LMVs) and dual-labeled MVs (annexin V⁺CD144⁺EMVs), were elevated in elderly patients with OSA. Circulating MVs were positively correlated with OSA severity (AHI, ODI, and SPO_2min). To some extent, obesity affected the MV concentrations in elderly patients with OSA. In addition, age and comorbidities may be associated with MV levels, but the correlations between the MV levels and age or comorbidities were not significant.

Conclusion: Concentrations of circulating MVs in elderly patients with OSA are associated with the labeling method used, OSA severity, and obesity. The effects of age and comorbidities on circulating MV levels require further verification using a larger sample size.

Effects of antithrombotic drugs on the prothrombotic state in patients with atrial fibrillation: The west Birmingham atrial fibrillation project

BACKGROUND

Direct oral anticoagulants (DOACs) are known to prevent thrombosis but there is limited information about their activity on the clot formation and lysis cascade.

OBJECTIVES

This study assesses the role of apixaban, one of the four licenced DOACs, on clot dynamics in patients with atrial fibrillation (AF).

METHODS

We compared haemostatic and clot lysis characteristics between a group of patients with AF (n = 47) and a "disease control" group with ischaemic heart disease but in sinus rhythm (n = 39). Subsequently, we conducted clot structure studies in 3 groups of patients with AF on different antithrombotic drugs: warfarin (n = 60), apixaban (n = 60) or antiplatelets (n = 62) and in patients with AF naïve to oral anticoagulants before and after 3-months treatment with apixaban (n = 32). Haemostasis was investigated by a viscoelastic, whole blood technique (Thromboelastography/TEG), a "microplate-reader based", citrated plasma technique (microplate assay), immunoassays to determine plasma concentrations of plasminogen activator inhibitor-1 (PAI-1), tissue-Plasminogen Activator (t-PA), D-dimer and finally platelet derived and apoptotic microparticles.

RESULTS

Patients with AF have more potent thrombogenesis based on microplate assay indices [Rate of clot formation (p = 0.03, ƞ² = 0.06), Maximum optical density (p < 0.001, ƞ² = 0.05)] and delayed fibrinolysis [Rate of clot dissolution (p = 0.005, ƞ² = 0.17)] with increased levels of apoptotic microparticles (p = 0.02, ƞ² = 0.06) compared with the 'disease control' group. Apixaban was more effective in attenuating prothrombotic characteristics assessed by TEG {R (ε² = 0.21), K (ε² = 0.16) and angle [mean difference (MD), 95% Confidence Intervals (CI), vs warfarin 5, 0.96-8.6 and 8, 3.8-11.4 vs antiplatelets], (p < 0.001 for all indices)} compared with the other treatment groups. Patients on apixaban had lower D-dimer (p < 0.001, ε² = 0.17) and tPA (p = 0.03, MD 90, 95%CI 6-150 vs warfarin and MD 90, 95% CI 4-150 vs antiplatelets) levels. From the microplate assay analysis, warfarin and apixaban demonstrated comparable activity based on multiple indices, both superior to antiplatelets. However, warfarin was associated with reduced fibrin network robustness (Max. optical density p < 0.001, ε² = 0.1). Apixaban inhibited thrombosis, amplified fibrinolysis and decreased D-dimer (p = 0.001, r = 0.4) levels in the follow up study.

CONCLUSIONS

Patients with AF have impaired haemostasis and elevated levels of apoptotic microparticles. Apixaban appears to affect plasma prothrombotic characteristics in a distinctive manner compared with warfarin and to reduce biomarkers associated with adverse cardiovascular events.

Exposure to Perfluoroalkyl Chemicals and Cardiovascular Disease: Experimental and Epidemiological Evidence

Polyfluoro- and perfluoro-alkyl substances (PFAS) are organic chemicals extensively used worldwide for industry and consumer products. Due to their chemical stability, PFAS represent a major cause of environmental pollution. PFAS accumulate in animal and human blood and tissues exerting their toxicity. We performed a review of the epidemiological studies exploring the relationship between exposure to PFAS and thromboembolic cardiovascular disease. An increase in cardiovascular disease or death related to PFAS exposure has been reported from cross-sectional and longitudinal observational studies with evidence concerning the relation with early vascular lesions and atherosclerosis. Several studies indicate an alteration in lipid and glucose metabolism disorders and increased blood pressure as a possible link with cardiovascular thromboembolic events. We also examined the recent evidence indicating that legacy and new PFAS can be incorporated in platelet cell membranes giving a solid rationale to the observed increase risk of cardiovascular events in the populations exposed to PFAS by directly promoting thrombus formation. Exposure to PFAS has been related to altered plasma membrane fluidity and associated with altered calcium signal and increased platelet response to agonists, both in vitro and ex vivo in subjects exposed to PFAS. All the functional responses are increased in platelets by incorporation of PFAS: adhesion, aggregation, microvesicles release and experimental thrombus formation. These findings offer mechanistic support the hypothesis that platelet-centred mechanisms may be implicated in the increase in cardiovascular events observed in populations chronically exposed to PFAS.

Procoagulant microparticles are associated with arterial disease in patients with systemic lupus erythematosus

Microparticles (MPs) have been associated with inflammatory and thrombotic disease. High levels of MPs have been identified in patients with systemic lupus erythematosus (SLE) and associated with cardiovascular disease. We analyzed the procoagulant activity of MPs and its correlation with arteriosclerosis and arterial thrombosis in SLE patients. Eighty-seven patients with SLE were included: 22 (25.3%) with associated antiphospholipid syndrome (APS), 32 (36.8%) without antiphospholipid antibodies (aPL) and 33 (37.9%) with aPL but without APS. Subclinical arteriosclerosis, defined as the presence and number of plaques, was evaluated by ultrasonography of carotid arteries. Thrombotic events were confirmed by objective methods. The procoagulant activity of MPs was determined by a functional assay with annexin V. Subclinical arteriosclerosis was found in 19 (21.8%) patients. Thirteen episodes of arterial thrombosis and eight of venous thrombosis were recorded. The procoagulant activity of MPs was greater in patients with arterial thrombosis (17.28 ± 8.29 nM vs 12.96 ± 7.90 nM, p < 0.05). In patients without arterial thrombosis, greater procoagulant activity of MPs was identified in patients with multiple (≥ 2) carotid plaques (17.26 ± 10.63 nM vs 12.78 ± 7.15 nM, p = 0.04). In the multivariate analysis, the procoagulant activity of MPs was independently associated with multiple (≥ 2) carotid plaques and arterial thrombosis [OR = 1.094 (95%CI 1.010-1.185), p = 0.027 and OR = 1.101 (95%CI 1.025-1.182), p = 0.008; respectively]. In conclusion, the procoagulant activity of MPs is associated with arteriosclerosis burden and arterial thrombosis in patients with SLE.

Impact of Epicatechin on the Procoagulant Activities of Microparticles

Microparticles play a role in cardiovascular disease pathology. The flavanol-like epicatechin is increasingly considered due to its cardioprotective effects. The aim of this study was to investigate the impact of epicatechin on microparticle generation, phenotype and procoagulant properties. Plasma samples from 15 healthy subjects were incubated with increasing concentrations of epicatechin (1 to 100 μM). Then, the expression of glycoprotein IIb, phosphatidylserine (PS), glycoprotein Ib (GPIb) and P-selectin was assessed by flow cytometry analysis after (or not) platelet stimulation. Microparticle procoagulant activity was determined using Zymuphen^TM MP and Zymuphen^TM MP-TF for phospholipid and tissue factor content, and with thrombin generation (TG) assays for procoagulant function. Platelet microparticles that express GPIb (/µL) decreased from 20,743 ± 24,985 (vehicle) to 14,939 ± 14,333 (p = 0.6), 21,366 ± 16,949 (p = 0.9) and 15,425 ± 9953 (p < 0.05) in samples incubated with 1, 10 and 100 µM epicatechin, respectively. Microparticle concentration (nM PS) decreased from 5.6 ± 2.0 (vehicle) to 5.1 ± 2.2 (p = 0.5), 4.5 ± 1.5 (p < 0.05) and 4.7 ± 2.0 (p < 0.05) in samples incubated with 1, 10 and 100µM epicatechin, respectively. Epicatechin had no impact on tissue factor-positive microparticle concentration. Epicatechin decreased TG (endogenous thrombin potential, nM.min) from 586 ± 302 to 509 ± 226 (p = 0.3), 512 ± 270 (p = 0.3) and 445 ± 283 (p < 0.05). These findings indicate that epicatechin affects microparticle release, phenotype and procoagulant properties.