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

Biochanin A inhibits endothelial dysfunction induced by IL‑6‑stimulated endothelial microparticles in Perthes disease via the NFκB pathway

Endothelial dysfunction caused by the stimulation of endothelial microparticles (EMPs) by the inflammatory factor IL-6 is one of the pathogenic pathways associated with Perthes disease. The natural active product biochanin A (BCA) has an anti-inflammatory effect; however, whether it can alleviate endothelial dysfunction in Perthes disease is not known. The present in vitro experiments on human umbilical vein endothelial cells showed that 0-100 pg/ml IL-6-EMPs could induce endothelial dysfunction in a concentration-dependent manner, and the results of the Cell Counting Kit 8 assay revealed that, at concentrations of <20 µM, BCA had no cytotoxic effect. Reverse transcription-quantitative PCR demonstrated that BCA reduced the expression levels of the endothelial dysfunction indexes E-selectin and intercellular cell adhesion molecule-1 (ICAM-1) in a concentration-dependent manner. Immunofluorescence and western blotting illustrated that BCA increased the expression levels of zonula occludens-1 and decreased those of ICAM-1. Mechanistic studies showed that BCA inhibited activation of the NFκB pathway. In vivo experiments demonstrated that IL-6 was significantly increased in the rat model of ischemic necrosis of the femoral head, whereas BCA inhibited IL-6 production. Therefore, in Perthes disease, BCA may inhibit the NFκB pathway to suppress IL-6-EMP-induced endothelial dysfunction, and could thus be regarded as a potential treatment for Perthes disease.

A preventative role of nitrate for hypoxia-induced intestinal injury

BACKGROUND

Studying effective interventions for hypoxia-induced injury is crucial, particularly in high-altitude areas. Symptoms stemming from intestinal injuries have a significant impact on the health of individuals transitioning from plains to plateau regions. This research explores the effects and mechanisms of nitrate supplementation in preventing hypoxia-induced intestinal injury.

METHODS

A hypoxia survival mouse model was established using 7% O2 conditions. The intervention with 4 mM sodium nitrate (NaNO3) in drinking water commenced 7 days prior to hypoxia exposure. Weight monitoring, hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), and intestinal permeability assays were employed for physiological, histological, and functional analyses. Quantitative PCR (qPCR), Western blot, and immunofluorescence were utilized to analyze the levels of tight junction (TJ) proteins and hypoxia-inducible factor 1α (Hif 1α). RNA sequencing (RNA-seq) identified nitrate's target, and chromatin immunoprecipitation (ChIP) verified the transcriptional impact of Hif 1α on TJ proteins. Villin-cre mice infected with AAV9-FLEX-EGFP-Hif 1α were used for mechanism validation.

RESULTS

The results demonstrated that nitrate supplementation significantly alleviated small intestinal epithelial cell necrosis, intestinal permeability, disruption of TJs, and weight loss under hypoxia. Moreover, the nitrate-triggered enhancement of TJs is mediated by Hif 1α nuclear translocation and its subsequent transcriptional function. The effect of nitrate supplementation on TJs was largely attributed to the stimulation of the EGFR/PI3K/AKT/mTOR/Hif 1α signaling pathways.

CONCLUSION

Nitrate serves as a novel approach in preventing hypoxia-induced intestinal injury, acting through Hif 1α activation to promote the transcription of TJ proteins. Furthermore, our study provides new and compelling evidence for the protective effects of nitrate in hypoxic conditions, especially at high altitudes.

Circulating Extracellular Vesicles in Subarachnoid Hemorrhage Patients: Characterization and Cellular Effects

Circulating extracellular vesicles (EVs) may play a pathophysiological role in the onset of complications of subarachnoid hemorrhage (SAH), potentially contributing to the development of vasospasm (VP). In this study, we aimed to characterize circulating EVs in SAH patients and examine their effects on endothelial and smooth muscle cells (SMCs). In a total of 18 SAH patients, 10 with VP (VP), 8 without VP (NVP), and 5 healthy controls (HC), clinical variables were recorded at different time points. EVs isolated from plasma samples were characterized and used to stimulate human vascular endothelial cells (HUVECs) and SMCs. We found that EVs from SAH patients expressed markers of T-lymphocytes and platelets and had a larger size and a higher concentration compared to those from HC. Moreover, EVs from VP patients reduced cell viability and mitochondrial membrane potential in HUVECs and increased oxidants and nitric oxide (NO) release. Furthermore, EVs from SAH patients increased intracellular calcium levels in SMCs. Altogether, our findings reveal an altered pattern of circulating EVs in SAH patients, suggesting their pathogenic role in promoting endothelial damage and enhancing smooth muscle reactivity. These results have significant implications for the use of EVs as potential diagnostic/prognostic markers and therapeutic tools in SAH management.

Association of amino acids and parameters of bone metabolism with endothelial dysfunction and vasculopathic changes in limited systemic sclerosis

Objectives

Pathways contributing to endothelial dysfunction in patients with limited cutaneous systemic sclerosis (lcSSc) are largely unknown. The aim of this study was to investigate potential associations of amino acids and parameters of bone metabolism with endothelial dysfunction and vasculopathy-related changes in patients with lcSSc and early-stage vasculopathy.

Methods

Amino acids, calciotropic parameters, including 25-hydroxyvitamin D and parathyroid hormone (PTH), and bone turnover parameters, including osteocalcin and N-terminal peptide of procollagen-3 (P3NP), were measured in 38 lcSSc patients and 38 controls. Endothelial dysfunction was assessed by biochemical parameters, pulse-wave analysis, flow-mediated and nitroglycerine-mediated dilation. Additionally, vasculopathy-related and SSc-specific clinical changes including capillaroscopic, skin, renal, pulmonary, gastrointestinal and periodontal parameters were recorded.

Results

No significant differences in amino acids, calciotropic and bone turnover parameters were observed between lcSSc patients and controls. In patients with lcSSc, several significant correlations were found between selected amino acids, parameters of endothelial dysfunction, vasculopathy-related and SSc-specific clinical changes (all with p < 0.05). In addition, significant correlations were observed between PTH and 25-hydroxyvitamin D with homoarginine, and between osteocalcin, PTH and P3NP with modified Rodnan skin score and selected periodontal parameters (all with p < 0.05). Vitamin D deficiency defined as 25-hydroxyvitamin D < 20 ng/ml was associated with the presence of puffy finger (p = 0.046) and early pattern (p = 0.040).

Conclusion

Selected amino acids may affect endothelial function and may be associated to vasculopathy-related and clinical changes in lcSSc patients, while the association with parameters of bone metabolism seems to be minor.

Periodontal disease and its association to endothelial dysfunction and clinical changes in limited systemic sclerosis: A case-control study

OBJECTIVES

Periodontal disease occurs frequently in patients with limited cutaneous systemic sclerosis (lcSSc) while data about underlying pathways contributing to periodontal changes are scarce. The aim of this study was to evaluate periodontal disease and to investigate its association with endothelial dysfunction and clinical changes in patients with lcSSc.

METHODS

In 38 lcSSc patients and 38 controls, periodontal status was evaluated by disease-specific questionnaire, dental examination including bleeding on probing (BOP), pocket depth, and plaque index, and dental panoramic radiograph. Periodontopathogen bacteria were collected subgingivally using paper points and interleukin-1 (IL-1) gene polymorphisms were evaluated using buccal swabs. Endothelial dysfunction was measured by flow-mediated dilatation, pulse-wave velocity and biochemical analysis, including arginine metabolites and endothelial microparticles. Additionally, lcSSc-specific clinical changes and parameters were recorded.

RESULTS

Periodontitis was present in 31 patients with lcSSc (81.6%) and in 27 controls (71.1%) (p = .280). LcSSc patients had a lower teeth number (p = .039) and Eikenella corrodens was to a higher degree detectable in patients with lcSSc (p = .041) while the remaining periodontal parameters revealed no differences between both cohorts. Significant correlations between parameters of arterial stiffness, EUSTAR index, number of teeth and BOP were observed (all p < .05). Detection of Prevotella intermedia was associated with selected IL-1 gene polymorphisms (p = .032) and Porphyromonas gingivalis was associated with severe periodontitis (p = .041).

CONCLUSION

Periodontal disease may occur frequently in patients with lcSSc and may be associated with arterial stiffness and with SSc activity.

Intravenous iron supplementation in heart failure patients induces temporary endothelial dysfunction with release of endothelial microvesicles

Background

Intravenous iron supplementation is an established therapy for patients with heart failure (HF) and concomitant iron deficiency reducing the risk of HF hospitalization. However, concerns persist regarding potential adverse vascular effects, since iron may induce oxidative stress, inflammation, and apoptosis of endothelial cells. To assess endothelial health following ferric carboxymaltose (FCM) administration, we analyzed the profile of circulating endothelial microvesicles (EMVs) and endothelial progenitor cells (EPCs) in a cohort of 23 HF patients using flow cytometry.

Results

Compared to healthy subjects, baseline levels of CD31+/CD41- EMVs were higher and EMVs featured a more apoptotic phenotype in HF patients. Following FCM administration, EMV levels showed a rapid but transient increase and displayed an altered phenotype profile with dominant augmentation of EMVs expressing inducible markers CD62E and CD54, indicating endothelial inflammatory activation and injury. Levels of circulating vasoregenerative CD45lowCD34+KDR+ EPCs were lower in HF patients and FCM application resulted in an early decrease of EPCs followed by substantial mobilization into the circulation after one week. Levels of EMVs and EPCs returned to baseline values within two and four weeks, respectively. HF patients with additional chronic kidney disease showed an elevated EMV/EPC ratio and diminished EPC mobilization, suggesting impaired vascular repair capacity. Providing a mechanistic link, in vitro experiments with cultured endothelial cells revealed that FCM dose-dependently promotes endothelial apoptosis, increases expression of adhesion molecules and CXCL12, and triggers generation of EMVs.

Conclusion

Intravenous iron supplementation with FCM in HF patients induces a biphasic response with initial increased release of CD62E+ and CD54+ enriched EMVs and subsequent mobilization of EPCs, indicating endothelial dysfunction upon FCM and suggesting consecutive engagement of a defense program aimed to reconstitute vascular health.

Association of Plasma Irisin Levels with Circulating Endothelial Microparticles (EMPs) and Endothelial Progenitor Cells (EPCs) in Children Born Prematurely

Prematurity has been linked with endothelial dysfunction in later life. The purpose of this study was to evaluate the association between plasma irisin, an adipomyokine reported to protect the functional integrity of vascular endothelium, and circulating endothelial microparticles (EMPs) and endothelial progenitor cells (EPCs), consisting early biomarkers of endothelial dysfunction, in preterm-born children. We studied 131 prepubertal children; 61 preterm and 70 born at term (controls). Plasma irisin was determined by ELISA. Circulating CD62E(+), CD144(+) and CD31(+)/CD42b(-) EMPs, and CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs, were determined by flow cytometry. Body mass index, waist-to-hip ratio, neck circumference, systolic and diastolic blood pressure, and biochemical parameters (glucose, lipids, insulin, HOMA-IR) were also evaluated. Plasma irisin was significantly lower (p = 0.001), whereas circulating EMPs and EPCs were higher, in children born prematurely compared to controls. Irisin was recognized as independent predictor for CD144(+) and CD31(+)/CD42b(-) EMPs, CD34(+)/VEGFR-2(+)/CD45(-) and CD34(+)/VEGFR-2(+)/CD45dim EPCs in the total study population, and for CD31(+)/CD42b(-) EMPs in the preterm group. In conclusion, plasma irisin correlates independently with circulating EMP and EPC subpopulations in prepubertal children and in preterm-born ones. Further studies in children will potentially elucidate the link between irisin and the primary stages of prematurity-related endothelial dysfunction.

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.

The potential applications of microparticles in the diagnosis, treatment, and prognosis of lung cancer

Microparticles (MPs) are 100–1000 nm heterogeneous submicron membranous vesicles derived from various cell types that express surface proteins and antigenic profiles suggestive of their cellular origin. MPs contain a diverse array of bioactive chemicals and surface receptors, including lipids, nucleic acids, and proteins, which are essential for cell-to-cell communication. The tumour microenvironment (TME) is enriched with MPs that can directly affect tumour progression through their interactions with receptors. Liquid biopsy, a minimally invasive test, is a promising alternative to tissue biopsy for the early screening of lung cancer (LC). The diverse biomolecular information from MPs provides a number of potential biomarkers for LC risk assessment, early detection, diagnosis, prognosis, and surveillance. Remodelling the TME, which profoundly influences immunotherapy and clinical outcomes, is an emerging strategy to improve immunotherapy. Tumour-derived MPs can reverse drug resistance and are ideal candidates for the creation of innovative and effective cancer vaccines. This review described the biogenesis and components of MPs and further summarised their main isolation and quantification methods. More importantly, the review presented the clinical application of MPs as predictive biomarkers in cancer diagnosis and prognosis, their role as therapeutic drug carriers, particularly in anti-tumour drug resistance, and their utility as cancer vaccines. Finally, we discussed current challenges that could impede the clinical use of MPs and determined that further studies on the functional roles of MPs in LC are required.

Endothelial Microparticles as Potential Biomarkers in the Assessment of Endothelial Dysfunction in Hypercholesterolemia

Background and Objectives: Endothelial microparticles (EMP) particularly CD31+/42−/AV+, CD144+/AV+ and CD62e+/AV+ have been reported as having increased in cardiovascular-related diseases, making them potential biomarkers for endothelial dysfunction. This study aimed to compare these EMPs in patients with hypercholesterolemia and healthy controls and to correlate their levels with endothelium-dependent vasodilation (EDV) assessed via pulse wave analysis (PWA); an established method of assessing endothelial function. Materials and Methods: EMPs from 88 subjects (44 hypercholesterolemia patients and 44 controls) were quantified from whole blood using flow cytometry analysis. Endothelial function was determined using PWA combined with pharmacological challenge. Results: CD31+/42−/AV+ (3.45 ± 4.74 count/µL vs. 1.33 ± 4.40 count/µL; p = 0.03), CD144+/AV+ (7.37 ± 12.66 count/µL vs. 1.42 ± 1.71 count/µL; p = 0.003) and CD62e+/AV+ (57.16 ± 56.22 count/µL vs. 20.78 ± 11.04 count/µL; p < 0.001) were significantly elevated in the hypercholesterolemic group compared with the controls, respectively. There was a significant inverse moderate correlation between all circulating EMPs and EDV: CD31+/42−/AV+ (r = −0.36, p = 0.001), CD144+/AV+ (r = −0.37, p = 0.001) and CD62e+/AV+ (r = −0.35, p = 0.002). Conclusions: All EMPs were raised in the patients with hypercholesterolemia, and these values correlated with the established method of assessing endothelial function.

Circulating microparticles as indicators of cardiometabolic risk in PCOS

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

Elevated circulating endothelial microparticles (EMPs) in prepubertal children born preterm

BACKGROUND

Endothelial microparticles (EMPs) act as early biomarkers of endothelial activation and damage. No studies have investigated EMPs in preterm-born individuals.

METHODS

Sixty-three preterm-born children and 52 children born full-term (controls) were studied. Circulating CD62E(+), CD144(+), and CD31(+)/CD42b(-) EMPs were measured in preterm-born children compared to controls; possible associations with cardiovascular risk factors and endothelial function parameters were also assessed.

RESULTS

Circulating CD62E(+), CD144(+), and CD31(+)/CD42b(-) EMPs were significantly higher in preterm-born children compared to controls (p = 0.003, p < 0.001, and p < 0.001, respectively). Preterm birth was recognized as an independent predictor of each EMP subpopulation studied; moreover, the mean pressure and velocity of pulmonary artery were independently correlated with CD62E(+) (β = 0.20, p = 0.04) and CD144(+) EMPs (β = 0.22, p = 0.02), respectively, whereas age (β = 0.21, p = 0.03) and being born SGA (β = 0.26, p = 0.01) correlated independently with CD31(+)/CD42b(-) EMPs in the study population. Furthermore, diastolic blood pressure (β = 0.24, p = 0.04), being born SGA (β = 0.24, p = 0.04) and the hyperemic peak velocity of the brachial artery (β = -0.65, p = 0.02) were independently associated with CD31(+)/CD42b(-) EMPs in the preterm-born group.

CONCLUSION

Circulating EMPs were higher in preterm-born children compared to children born full-term. Whether EMPs could act, in clinical practice, as a complementary tool for non-invasive evaluation of endothelium in preterm-born children, remains under investigation.

IMPACT

Circulating endothelial microparticles (EMPs) are small membrane vesicles released from endothelial cells and they act as novel biomarkers of endothelial activation and damage. No studies have investigated circulating EMPs in preterm-born individuals. Circulating EMPs were significantly higher in prepubertal preterm-born children compared to children born at term. In the preterm-born group, the hyperemic peak velocity of the brachial artery was independently associated with CD31(+)/CD42b(-) EMPs. Whether assessment of circulating EMPs could act, in clinical practice, as a complementary tool for non-invasive evaluation of endothelium in preterm-born children, remains to be defined in future investigations.

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.

Changes in hormones after apneic hypoxia/hypercapnia - an investigation in voluntary apnea divers

BACKGROUND

Prolonged apnea is characterized by hypoxia/hypercapnia. Hypoxia can be associated with hormonal dysfunction. We raised the question as to whether steroid hormonal and gonadotropin levels could be influenced by short-term hypoxia/hypercapnia in a model of dry apnea in trained apnea divers.

METHODS

Adrenal, sex steroid and pituitary hormones were measured in ten trained voluntary apnea divers before, immediately after, 0.5 h and 4 h after a maximal breath-hold. Apnea was carried out under dry conditions.

RESULTS

Corticosterone, progesterone, cortisol, 17-OH-progesterone, dehydroepiandrosterone and androstenedione showed a significant continuous increase with a maximum at 0.5 h after apnea, followed by a decrease back to or below baseline at 4 h after apnea. Testosterone, estradiol, cortisone and dihydrotestosterone showed a decrease 4 h after apnea. Dehydroepiandrosteronesulfate, luteinizing hormone (LH) and follicle stimulating hormone (FSH) showed no significant changes.

CONCLUSION

Even a single apnea resulted in two different patterns of hormone response to apnea, with increased adrenal and reduced sex steroid levels, while LH/FSH showed no clear kinetic reaction. Apnea divers might be a suitable clinical model for hypoxic disease.

Tracking Radiolabeled Endothelial Microvesicles Predicts Their Therapeutic Efficacy: A Proof-of-Concept Study in Peripheral Ischemia Mouse Model Using SPECT/CT Imaging

Microvesicles, so-called endothelial large extracellular vesicles (LEVs), are of great interest as biological markers and cell-free biotherapies in cardiovascular and oncologic diseases. However, their therapeutic perspectives remain limited due to the lack of reliable data regarding their systemic biodistribution after intravenous administration. Methods: Applied to a mouse model of peripheral ischemia, radiolabeled endothelial LEVs were tracked and their in vivo whole-body distribution was quantified by microSPECT/CT imaging. Hindlimb perfusion was followed by LASER Doppler and motility impairment function was evaluated up to day 28 post-ischemia. Results: Early and specific homing of LEVs to ischemic hind limbs was quantified on the day of ischemia and positively correlated with reperfusion intensity at a later stage on day 28 after ischemia, associated with an improved motility function. Conclusions: This concept is a major asset for investigating the biodistribution of LEVs issued from other cell types, including cancer, thus partly contributing to better knowledge and understanding of their fate after injection.

Differences in Endothelial Activation and Dysfunction Induced by Antiphospholipid Antibodies Among Groups of Patients With Thrombotic, Refractory, and Non-refractory Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by pregnancy morbidity or thrombosis and persistent antiphospholipid antibodies (aPL) that bind to the endothelium and induce endothelial activation, which is evidenced by the expression of adhesion molecules and the production of reactive oxygen species (ROS) and subsequent endothelial dysfunction marked by a decrease in the synthesis and release of nitric oxide (NO). These endothelial alterations are the key components for the development of severe pathological processes in APS. Patients with APS can be grouped according to the presence of other autoimmune diseases (secondary APS), thrombosis alone (thrombotic APS), pregnancy morbidity (obstetric APS), and refractoriness to conventional treatment regimens (refractory APS). Typically, patients with severe and refractory obstetric APS exhibit thrombosis and are classified as those having primary or secondary APS. The elucidation of the mechanisms underlying these alterations according to the different groups of patients with APS could help establish new therapies, particularly necessary for severe and refractory cases. Therefore, this study aimed to evaluate the differences in endothelial activation and dysfunction induced by aPL between patients with refractory obstetric APS and other APS clinical manifestations. Human umbilical vein endothelial cells (HUVECs) were stimulated with polyclonal immunoglobulin-G (IgG) from different groups of patients n = 21), including those with primary (VTI) and secondary thrombotic APS (VTII) and refractory primary (RI+), refractory secondary (RII+), and non-refractory primary (NR+) obstetric APS. All of them with thrombosis. The expression of adhesion molecules; the production of ROS, NO, vascular endothelial growth factor (VEGF), and endothelin-1; and the generation of microparticles were used to evaluate endothelial activation and dysfunction. VTI IgG induced the expression of adhesion molecules and the generation of microparticles and VEGF. RI+ IgG induced the expression of adhesion molecules and decreased NO production. RII+ IgG increased the production of microparticles, ROS, and endothelin-1 and reduced NO release. NR+ IgG increased the production of microparticles and endothelin-1 and decreased the production of VEGF and NO. These findings reveal differences in endothelial activation and dysfunction among groups of patients with APS, which should be considered in future studies to evaluate new therapies, especially in refractory cases.

Evaluation of Endothelial Dysfunction and Inflammatory Vasculopathy After SARS-CoV-2 Infection-A Cross-Sectional Study

Background: Rising data suggest that COVID-19 affects vascular endothelium while the underlying mechanisms promoting COVID-19-associated endothelial dysfunction and inflammatory vasculopathy are largely unknown. The aim was to evaluate the contribution of COVID-19 to persisting vascular injury and to identify parameters linked to COVID-19-associated endothelial dysfunction and inflammatory vasculopathy. Methods: In a cross-sectional design, flow-mediated dilation (FMD), nitroglycerine-related dilation (NMD), pulse-wave velocity (PWV), augmentation index, intima-media thickness (IMT), compounds of the arginine and kynurenine metabolism, homocysteine, von Willebrand factor (vWF), endothelial microparticles (EMP), antiendothelial cell antibodies, inflammatory, and immunological parameters, as well as nailfold capillary morphology were measured in post-COVID-19 patients, patients with atherosclerotic cardiovascular diseases (ASCVD) and healthy controls without prior or recent SARS-CoV-2 infection. Results: Post-COVID-19 patients had higher values of PWV, augmentation index, IMT, asymmetric and symmetric dimethylarginine, vWF, homocysteine, CD31+/CD42b- EMP, C-reactive protein, erythrocyte sedimentation rate, interleukin-6, and β-2-glycoprotein antibodies as well as lower levels of homoarginine and tryptophan compared to healthy controls (all with p < 0.05). A higher total number of pathologically altered inflammatory conditions and higher rates of capillary ramifications, loss, caliber variability, elongations and bushy capillaries with an overall higher microangiopathy evolution score were also observed in post-COVID-19 patients (all with p < 0.05). Most parameters of endothelial dysfunction and inflammation were comparably altered in post-COVID-19 patients and patients with ASCVD, including FMD and NMD. Conclusion: COVID-19 may affect arterial stiffness, capillary morphology, EMP and selected parameters of arginine, kynurenine and homocysteine metabolism as well as of inflammation contributing to COVID-19-associated endothelial dysfunction and inflammatory vasculopathy.

Vascular inflammation in moderate-to-severe atopic dermatitis is associated with enhanced Th2 response

BACKGROUND

In atopic dermatitis (AD), some studies have shown an association with increased cardiovascular disease in certain populations. However, other investigations found modest or no association. Despite conflicting results, molecular profiling studies in both AD skin and blood have demonstrated upregulation of atherosclerosis and cardiovascular risk-related markers. However, the underlying mechanisms connecting AD to vascular inflammation/atherosclerosis are unknown. In this study, we aim to determine factors associated with vascular inflammation/atherosclerosis in AD patients.

METHODS

We used 18-FDG PET-CT to characterize vascular inflammation in AD patients and healthy subjects. In parallel, we assessed their skin and blood immune profiles to determine AD-related immune biomarkers associated with vascular inflammation. We also assessed levels of circulating microparticles, which are known to be associated with increased cardiovascular risk.

RESULTS

We found significant correlations between vascular inflammation and Th2-related products in skin and blood of AD patients as well as atherosclerosis-related markers that were modulated by dupilumab. Circulating levels of endothelial microparticles were significantly higher in severe AD patients and tended to correlate with vascular inflammation assessed by PET-CT.

CONCLUSION

Vascular inflammation in AD is associated with enhanced Th2 response and clinical severity, which may explain cardiovascular comorbidities observed in select AD populations. Larger prospective studies are needed to further evaluate vascular inflammation and cardiovascular events and mortality in AD patients. Finally, as dupilumab treatment demonstrated significant modulation of atherosclerosis-related genes in AD patients compared to placebo, these data suggest that modulation of vascular inflammation with systemic treatment should be explored in patients with AD.

Effects of the L-tyrosine-derived bacterial metabolite p-cresol on colonic and peripheral cells

Specific families of bacteria present within the intestinal luminal content produce p-cresol from L-tyrosine. Although the hosts do not synthesize p-cresol, they can metabolize this compound within their colonic mucosa and liver leading to the production of co-metabolites including p-cresyl sulfate (p-CS) and p-cresyl glucuronide (p-CG). p-Cresol and its co-metabolites are recovered in the circulation mainly conjugated to albumin, but also in their free forms that are excreted in the urine. An increased dietary protein intake raises the amount of p-cresol recovered in the feces and urine, while fecal excretion of p-cresol is diminished by a diet containing undigestible polysaccharides. p-Cresol in excess is genotoxic for colonocytes. In addition, in these cells, this bacterial metabolite decreases mitochondrial oxygen consumption, while increasing the anion superoxide production. In chronic kidney disease (CKD), marked accumulation of p-cresol and p-CS in plasma is measured, and in renal tubular cells, p-cresol and p-CS increase oxidative stress, affect mitochondrial function, and lead to cell death, strongly suggesting that these 2 compounds act as uremic toxins that aggravate CKD progression. p-Cresol and p-CS are also suspected to play a role in the CKD-associated adverse cardiovascular events, since they affect endothelial cell proliferation and migration, decrease the capacity of endothelial wound repair, and increase the senescence of endothelial cells. Finally, the fact that concentration of p-cresol is transiently increased in young autistic children biological fluids, and that intraperitoneal injection of p-cresol in animal models induces some behavioral characteristics observed in the autism spectrum disorders (ASD), raise the view that p-cresol may possibly represent one of the components involved in ASD etiology. Further pre-clinical and clinical studies are obviously needed to determine if the lowering of p-cresol and/or p-CS circulating concentrations, by dietary and/or pharmacological means, would allow, by itself or in combination with other interventions, to improve CKD progression and associated cardiovascular outcomes, as well as some neurological outcomes in children with an early diagnosis of autism.

Endothelial microparticle-associated protein disulfide isomerase increases platelet activation in diabetic coronary heart disease

Background: Endothelial microparticles (EMPs) carrying the protein disulfide isomerase (PDI) might play a key role in promoting platelet activation in diabetes. This study aimed to examine the activation of platelets, the amounts of MPs, PMPs, and EMPs, and the concentration and activity of PDI in patients with diabetic coronary heart disease (CHD) and non-diabetic CHD.

Methods: Patients with CHD (n=223) were divided as non-diabetic CHD (n=121) and diabetic CHD (n=102). Platelet activation biomarkers, circulating microparticles (MPs), the concentration of protein disulfide isomerase (PDI), and MP-PDI activity were determined. The effect of EMPs on platelet activation was investigated in vitro. Allosteric GIIb/IIIa receptors that bind to PDI were detected by a proximity ligation assay (PLA).

Results: Platelet activation, platelet-leukocyte aggregates, circulating MPs, EMPs, PDI, and MP-PDI activity in the diabetic CHD group were significantly higher than in the non-diabetic CHD group (P<0.05). Diabetes (P=0.006) and heart rate <60 bpm (P=0.047) were associated with elevated EMPs. EMPs from diabetes increased CD62p on the surface of the platelets compared with the controls (P<0.01), which could be inhibited by the PDI inhibitor RL90 (P<0.05). PLA detected the allosteric GIIb/IIIa receptors caused by EMP-PDI, which was also inhibited by RL90.

Conclusions: In diabetic patients with CHD, platelet activation was significantly high. Diabetes and heart rate <60 bpm were associated with elevated EMPs and simultaneously increased PDI activity on EMP, activating platelets through the allosteric GPIIb/IIIa receptors.

Serum Extracellular Vesicle-Derived miR-124-3p as a Diagnostic and Predictive Marker for Early-Stage Acute Ischemic Stroke

Background: A delay in the diagnosis of acute ischemic stroke (AIS) reduces the eligibility and outcome of patients for thrombolytic therapy. Therefore, early diagnosis and treatment of AIS are crucial. The present study evaluated the sensitivity and accuracy of serum extracellular vesicle (EV)-derived miR-124-3p in the diagnosis and prediction of AIS.

Methods: An miRNA expression profile was downloaded from Gene Expression Omnibus (GEO) database and analyzed by R software. EVs were harvested from the serum of AIS patients using a total exosome isolation kit and characterized by Western blotting, a transmission electron microscope, and the nanoparticle tracking analysis. BV2 microglia were pre-stimulated with lipopolysaccharide (LPS), followed by miR-124-3p treatment for 24 h and subsequent analysis of viability, apoptosis, and migration (scratch assay), and Western blotting. The relative expression of the selected genes was assessed by qRT-PCR. The phosphorylation of Erk1/2, PI3K/Akt, and p38MAPK in BV2 microglia cells was evaluated by Western blotting, while the luciferase reporter gene assay detected the correlation between key genes involved in the pro-inflammatory signaling pathways and miR-124-3p.

Results:hsa-miR-124-3p was downregulated in AIS serum compared to the non-AIS serum (p < 0.05), and the gene expression of has-miR-124-3p in EVs was negatively correlated with serum pro-inflammatory cytokines and the NIHSS (p < 0.05). In addition, miR-124-3p promoted the viability and inhibited the apoptosis of LPS-induced BV2 microglia. Furthermore, miR-124-3p reduced the phosphorylation of Erk1/2, PI3K/Akt, and p38MAPK, and promoted the migration in LPS-induced BV2 microglia (p < 0.05).

Conclusion: Serum EV-derived miR-124-3p serves as a diagnostic and predictive marker for early-stage AIS.

Understanding extracellular vesicle and nanoparticle heterogeneity: Novel methods and considerations

Extracellular vesicles (EVs) are a heterogeneous population of membrane-enclosed nanoparticles released by cells. They play a role in intercellular communication and are involved in numerous physiological and pathological processes. Cells release subpopulations of EVs with distinct composition and inherent biological function which overlap in size. Current size-based isolation methods are, therefore, not optimal to discriminate between functional EV subpopulations. In addition, EVs overlap in size with several other biological nanoparticles, such as lipoproteins and viruses. Proteomic analysis has allowed for more detailed study of EV composition, and EV isolation approaches based on this could provide a promising alternative for purification based on size. Elucidating EV heterogeneity and the characteristics and role of EV subpopulations will advance our understanding of EV biology and the role of EVs in health and disease. Here, we discuss current knowledge of EV composition, EV heterogeneity and advances in affinity based EV isolation tools.

Protective Effect of Salidroside on Mitochondrial Disturbances via Reducing Mitophagy and Preserving Mitochondrial Morphology in OGD-induced Neuronal Injury

Salidroside is the active ingredient extracted from Rhodiola rosea, and has been reported to show protective effects in cerebral ischemia, but the exact mechanisms of neuronal protective effects are still unrevealed. In this study, the protective effects of salidroside (1 µmol/L) in ameliorating neuronal injuries induced by oxygen-glucose deprivation (OGD), which is a classical model of cerebral ischemia, were clarified. The results showed that after 8 h of OGD, the mouse hippocampal neuronal cell line HT22 cells showed increased cell death, accompanied with mitochondrial fragmentation and augmented mitophagy. However, the cell viability of HT22 cells showed significant restoration after salidroside treatment. Mitochondrial morphology and mitochondrial function were effectively preserved by salidroside treatment. The protective effects of salidroside were further related to the prevention of mitochondrial over-fission. The results showed that mTOR could be recruited to the mitochondria after salidroside treatment, which might be responsible for inhibiting excessive mitophagy caused by OGD. Thus, salidroside was shown to play a protective role in reducing neuronal death under OGD by safeguarding mitochondrial function, which may provide evidence for further translational studies of salidroside in ischemic diseases.

Effects of structured home-based exercise training on circulating endothelial progenitor cells and endothelial function in patients with intermittent claudication

INTRODUCTION

Exercise training improves walking capacity in patients with intermittent claudication (IC). Endothelial progenitor cells (EPCs), endothelial microparticles (EMPs), and endothelial dysfunction could play a role in this process.

METHODS

We measured EPCs and EMPs in a group of 60 patients with IC, and in a control group of 20 individuals without IC, before a treadmill test and 2, 24, and 48 hours after the test. Thirty patients with IC were randomly assigned to perform a 12-week home-based exercise training program. The EPC count, flow-mediated dilation (FMD) of the brachial artery, pain-free walking time (PFWT), and maximum walking time (MWT) were measured at the baseline and after the exercise training program.

RESULTS

In patients with IC, EMPs significantly increased 2 hours after the treadmill test, whereas EPCs significantly increased after 24 hours. Among the subjects assigned to complete the training program, we observed a significant increase in the number of EPCs after 12 weeks, as well as an improvement in FMD, PFWT, and MWT. A significant correlation between the variation of EPCs, FMD, and MWT was found. The increase of EPCs and FMD were independent determinants of the walking capacity improvement, without significant interaction.

CONCLUSION

Our results suggest that EPCs mobilization contributes to the improvement of walking capacity in patients with IC undergoing structured physical training. A number of different, partly independent, mechanisms are involved in this process, and our results highlight the potential role of EMPs release and endothelial function improvement. ClinicalTrials.gov Identifier: NCT04302571.

Biomarkers for Antiplatelet Therapies in Acute Ischemic Stroke: A Clinical Review

Stroke is one of the world's leading causes of disability and death. Antiplatelet agents are administered to acute ischemic stroke patients as secondary prevention. Clopidogrel involves biotransformation by cytochrome P450 (CYP) enzymes into an active metabolite, and single nucleotide polymorphisms (SNPs) can influence the efficacy of this biotransformation. Despite the therapeutic advantages of aspirin, there is significant inter-individual heterogeneity in response to this antiplatelet drug. In this clinical review, the recent advances in the biomarkers of antiplatelet agents in acute ischemic stroke are discussed. The studies reviewed herein highlight the clinical relevance of antiplatelet resistance, pharmacotherapy of antiplatelet agents predicting drug response, strategies for identifying aspirin resistance, pharmacogenetic variants of antiplatelet agents, miRNAs, and extracellular vesicles (EVs) as biomarkers toward the personalized approach in the management of acute ischemic stroke. The precise pathways contributing to antiplatelet resistance are not very well known but are presumably multi-factorial. It is essential to understand the clinical relevance of clopidogrel and aspirin-related single nucleotide polymorphism (SNPs) as potential predictive and prognostic biomarkers. Prasugrel is a next-generation antiplatelet agent that prevents ADP-platelet activation by binding irreversibly to P2Y12 receptor. There are sporadic reports of prasugrel resistance and polymorphisms in the Platelet endothelial aggregation receptor-1 (PEAR1) that may contribute to a change in the pharmacodynamics response. Ticagrelor, a direct-acting P2Y12-receptor antagonist, is easily absorbed and partly metabolized to major AR-C124910XX metabolite (ARC). Ticagrelor's primary active metabolite, ARC124910XX (ARC), is formed via the most abundant hepatic cytochrome P450 (CYP) enzyme, CYP3A4, and CYP3A5. The integration of specific biomarkers, genotype as well as phenotype-related data in antiplatelet therapy stratification in patients with acute ischemic stroke will be of great clinical significance and could be used as a guiding tool for more effective, personalized therapy.

Uremic endothelial-derived extracellular vesicles: Mechanisms of formation and their role in cell adhesion, cell migration, inflammation, and oxidative stress

p-Cresyl sulfate (PCS), indoxyl sulfate (IS), and inorganic phosphate (Pi) are uremic toxins found in chronic kidney disease (CKD) that are closely related to endothelial extracellular vesicles (EVs) formation. The present study aimed to understand the role of EVs and their role in cell adhesion and migration, inflammation, and oxidative stress. Human endothelial cells were treated with PCS, IS, and Pi in pre-established uremic and kinetic recommendations. EVs were characterized using scanning electron microscopy, flow cytometry, and NanoSight assays. The concentrations of EVs were established using Alamar Blue and MTT assays. Cell adhesion to extracellular matrix proteins was analyzed using an adhesion assay. Inflammation and oxidative stress were assessed by vascular cell adhesion molecule-1 expression/monocyte migration and reactive oxygen species production, respectively. The capacity of EVs to stimulate endothelial cell migration was evaluated using a wound-healing assay. Our data showed that endothelial cells stimulated with uremic toxins can induce the formation of EVs of different sizes, quantities, and concentrations, depending on the uremic toxin used. Cell adhesion was significantly (P < 0.01) stimulated in cells exposed to PCS-induced extracellular vesicles (PCSEVs) and inorganic phosphate-induced extracellular vesicles (PiEVs). Cell migration was significantly (P < 0.05) stimulated by PCSEVs. VCAM-1 expression was evident in cells treated with PCSEVs and IS-induced extracellular vesicles (ISEVs). EVs are not able to stimulate monocyte migration or oxidative stress. In conclusion, EVs may be a biomarker of endothelial injury and the inflammatory process, playing an important role in cell-to-cell communication and pathophysiological processes, although more studies are needed to better understand the mechanisms of EVs in uremia.

A Translational Investigation of IFN-α and STAT1 Signaling in Endothelial Cells during Septic Shock Provides Therapeutic Perspectives

Septic shock and disseminated intravascular coagulation (DIC) are known to be characterized by an endothelial cell dysfunction. The molecular mechanisms underlying this relationship are, however, poorly understood. In this work, we aimed to investigate human circulating IFN-α in patients with septic shock-induced DIC and tested the potential role of endothelial Stat1 (signal transducer and activator of transcription 1) as a therapeutic target in a mouse model of sepsis. For this, circulating type I, type II, and type III IFNs and procoagulant microvesicles were quantified in a prospective cohort of patients with septic shock. Next, we used a septic shock model induced by cecal ligation and puncture in wild-type mice, in Ifnar1 (type I IFN receptor subunit 1)-knockout mice, and in Stat1 conditional knockout mice. In human samples, we observed higher concentrations of circulating IFN-α and IFN-α1 in patients with DIC compared with patients without DIC, whereas concentrations of IFN-β, IFN-γ, IFN-λ1, IFN-λ2, and IFN-λ3 were not different. IFN-α concentration was positively correlated with CD105 microvesicle concentrations, reflecting endothelial injury. In Ifnar1^-/- mice, cecal ligation and puncture did not induce septic shock and was characterized by lesser endothelial cell injury, with lower aortic inflammatory cytokine expression, endothelial inflammatory-related gene expression, and fibrinolysis. In mice in which Stat1 was specifically ablated in endothelial cells, a marked protection against sepsis was also observed, suggesting the relevance of an endothelium-targeted strategy. Our work highlights the key roles of type I IFNs as pathogenic players in septic shock-induced DIC and the potential pertinence of endothelial STAT1 as a therapeutic target.

Association between Urinary Phthalate Metabolites and Markers of Endothelial Dysfunction in Adolescents and Young Adults

Endothelial function is crucial in the pathogenesis of circulatory and cardiovascular toxicity; epidemiologic research investigating the association between phthalate exposure and endothelial dysfunction remains limited. We examined the associations between exposures to specific phthalates (di-2-ethylhexyl phthalate, DEHP; di-n-butyl phthalate, DnBP) and circulating endothelial and platelet microparticles (EMPs and PMPs) in adolescents and young adults. Of the 697 participants recruited, anthropometric measurements and health-related behaviors relevant to cardiovascular risks were collected and assessed. Urine and serum were collected and analyzed with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and flow cytometry. Multiple linear regression indicated that increases in urinary concentrations of ΣDEHP and MnBP (mono-n-butyl phthalate), across quartiles, were positively associated with serum EMPs level (p for trend <0.001 and <0.001; β = 0.798 and 0.007; standard error = 0.189 and 0.001, respectively). Moreover, female and overweight subjects had higher MnBP, and males were more vulnerable to DnBP exposure compared to females. In conclusion, our results demonstrate a dose-response relationship between exposures to phthalates (ΣDEHP and MnBP) and microparticle formation (EMPs and PMPs) in adolescents and young adults. The findings indicate that exposures to phthalates of both low and high-molecular weight are positively associated with microparticle production, and might contribute to endothelial dysfunction; such damage might manifest in the form of atherosclerotic-related vascular diseases. Future in vivo and in vitro studies are warranted to elucidate whether a causal relationship exists between phthalate exposure and EMPs and PMPs.

Plasma Concentrations of Extracellular Vesicles Are Decreased in Patients with Post-Infarct Cardiac Remodelling

Simple Summary

A heart attack may lead to the remodelling of the cardiac muscle, which negatively affects patient’s prognosis. At present, the mechanisms of cardiac remodelling remain unclear. In patients with heart attack, many body cells become activated and release small particles, called extracellular vesicles, which can either aggravate cardiac injury, or contribute to healing of heart muscle. In our study, we hypothesized that the concentrations of these small particles in plasma allow to determine which patients will experience remodelling of the cardiac muscle after the heart attach. We found that concentrations of extracellular vesicles from endothelial cells, erythrocytes and platelets, measured directly the heart attack, were lower in patients who developed cardiac remodelling 6 months later, compared to patients who had no remodelling. Vesicles from endothelial cells and erythrocytes allowed to determine remodelling independently of other clinical features. Hence, decreased concentrations of these vesicles may on one hand be a sign of inappropriate cardiac repair mechanisms, and on the other hand may allow to identify patients, who will develop cardiac remodelling after the heart attack.

Abstract

Background, the mechanisms underlying left ventricular remodelling (LVR) after acute myocardial infarction (AMI) remain obscure. In the course of AMI, blood cells and endothelial cells release extracellular vesicles (EVs). We hypothesized that changes in EV concentrations after AMI may underlie LVR. Methods, plasma concentrations of EVs from endothelial cells (CD146+), erythrocytes (CD235a+), leukocytes (CD45+), platelets (CD61+), activated platelets (P-selectin+), and EVs exposing phosphatidylserine after AMI were determined by flow cytometry in 55 patients with the first AMI. LVR was defined as an increase in left ventricular end-diastolic volume by 20% at 6 months after AMI, compared to baseline. Results, baseline concentrations of EVs from endothelial cells, erythrocytes and platelets were lower in patients who developed LVR (p ≤ 0.02 for all). Concentrations of EVs from endothelial cells and erythrocytes were independent LVR predictors (OR 8.2, CI 1.3–54.2 and OR 17.8, CI 2.3–138.6, respectively) in multivariate analysis. Combining the three EV subtypes allowed to predict LVR with 83% sensitivity and 87% specificity. Conclusions, decreased plasma concentrations of EVs from endothelial cells, erythrocytes and platelets predict LVR after AMI. Since EV release EVs contributes to cellular homeostasis by waste removal, decreased concentrations of EVs may indicate dysfunctional cardiac homeostasis after AMI, thus promoting LVR.

Anti-endothelial cell antibodies are associated with apoptotic endothelial microparticles, endothelial sloughing and decrease in angiogenic progenitors in systemic sclerosis

Introduction

Evidence has accumulated for the role of endothelial damage in systemic sclerosis (SSc) and the anti-endothelial cell antibodies (AECAs) might underlie vascular injury.

Aim

Since endothelial microparticles (EMPs) and circulating endothelial cells (CECs) reflect endothelial damage, we aimed to investigate their possible relationship with AECAs in SSc. We examined whether AECAs could affect endothelial repair based on the number of endothelial progenitor cells (EPCs).

Material and methods

Forty-seven SSc patients were screened. The AECAs were identified in serum by indirect immunofluorescence. EPCs and CECs were isolated from the peripheral blood using anti-CD34-based immunomagnetic separation, whereas EMPs were analyzed in plasma. Flow cytometry was used to quantify EMPs, CECs and EPCs.

Results

AECAs were found in 21 (44.7%) SSc patients and were significantly associated with higher levels of total as well as apoptotic (AnnV+ and CD51+) EMPs, whereas activated (CD62E+/AnnV–) EMPs did not differ between groups. Patients with AECAs had significantly elevated total CECs as well as activated CD105+ CECs. Total endothelial progenitors did not differ between patients with or without AECAs; however AECAs was negatively associated with the population of EPCs that express VEGFR2 or Tie2 receptors.

Conclusions

We found an association between AECAs and the severity of endothelial damage in SSc based on higher levels of total EMPs and CECs. In our study, AECAs were associated with apoptosis of ECs rather than their activation. We also identified a possible role of AECAs in the impairment of vascular repair in SSc as evidenced by significantly fewer angiogenic EPCs.

Increased circulating CD31+/CD42b-EMPs in Perthes disease and inhibit HUVECs angiogenesis via endothelial dysfunction

AIMS

Endothelial microparticles (EMPs) are extracellular vesicles secreted by endothelial cells. The purpose of this research is to explore that the clinical significance and roles in angiogenesis and endothelial dysfunction of circulating microparticles in Perthes disease.

MAIN METHODS

We collected platelet-poor plasma (PPP) from patients and controls, then microparticles (MPs) were extracted. Flow cytometry was performed to calculate the concentrations of CD31+/CD42b-, CD62E+ and CD31+/CD42b+ MPs. ELISA was performed to detect the expression level of biomarkers of endothelial dysfunction and inflammatory factors in plasma. In vitro experiments to evaluate the effect of circulating MPs and EMPs derived from IL-6-stimulated human umbilical vein endothelial cells (HUVECs) on angiogenesis and endothelial dysfunction.

KEY FINDINGS

Our results revealed that the CD31+/CD42b- EMPs were significantly higher in Perthes disease group than in the control group. The Perthes-MPs being taken up by HUVECs promoted endothelial cell apoptosis, endothelial dysfunction and inhibited angiogenesis in vitro. Moreover, the level of IL-6 in plasma significantly increased in patients with Perthes, which was tightly correlated with the elevated level of circulating CD31+/CD42b- EMPs. IL-6 promoted HUVECs to secrete CD31+/CD42b- MPs, and EMPs derived from high concentration IL-6-stimulated (100 and 1000 pg/mL) HUVECs promoted endothelial cell apoptosis, endothelial dysfunction and inhibited angiogenesis.

SIGNIFICANCE

In summary, our study suggests that circulating EMPs in the phenotypic spectrum revealed unique phenotypes of endothelial dysfunction, showing close correlation with the secretion of IL-6. These circulating EMPs may give rise to endothelial cell apoptosis, endothelial dysfunction and angiogenesis in Perthes disease.

Interplay of pro-inflammatory cytokines, pro-inflammatory microparticles and oxidative stress and recurrent ventricular arrhythmias in elderly patients after coronary stent implantations

BACKGROUND

The roles of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress were unknown in elderly patients with recurrent ventricular arrhythmias (VA). We evaluated whether cross talk between oxidative stress, pro-inflammatory microparticles, and pro-inflammatory cytokines play the roles in elderly patients with recurrent VA after coronary stenting. This research sought to investigate the effects of oxidative stress, pro-inflammatory microparticles, and pro-inflammatory cytokines on recurrent VA in elderly patients after coronary stenting.

METHODS

In this study, we included 613 consecutive elderly patients with recurrent ventricular arrhythmias induced by coronary reocclusions after coronary stenting. We measured CD31⁺ endothelial microparticle (CD31⁺EMP), CD62E⁺ endothelial microparticle (CD62E⁺EMP), high-sensitivity C-reactive protein (hs-CRP), aldosterone (ALD), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), soluble tumor necrosis factor receptor-1 (sTNFR-1) and soluble tumor necrosis factor receptor-2 (sTNFR-2) in elderly patients with recurrent VA and assessed impacts of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress on recurrent VA in elderly patients after coronary stenting.

RESULTS

The levels of CD31⁺EMP, CD62E⁺EMP, hs-CRP, ALD, MDA, TNF-α, sTNFR-1 and sTNFR-2 were increased in recurrent malignant ventricular arrhythmia, sustained ventricular tachycardia, multiple ventricular premature beat and left and right ventricular bundle branch block groups (P < 0.001) in elderly patients with coronary reocclusions after coronary stent implantation. Upregulation of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress markers induced recurrent VA in elderly patients after coronary stenting.

CONCLUSIONS

High levels of pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress markers were associated with recurrent VA in elderly patients after coronary stenting. Our results suggested that the pro-inflammatory microparticles, pro-inflammatory cytokines and oxidative stress may simultaneously induce and aggravate recurrent VA in elderly patients after coronary stenting.

Extracellular Vesicles in Acute Stroke Diagnostics

There is a large unmet need for fast and reliable diagnostics in several diseases. One such disease is stroke, where the efficacy of modern reperfusion therapies is highly time-dependent. Diagnosis of stroke and treatment initiation should be performed as soon as possible, and preferably before arrival at the stroke center. In recent years, several potential blood biomarkers for stroke have been evaluated, but without success. In this review, we will go into detail on the possibility of utilizing extracellular vesicles (EVs) released into the blood as novel biomarkers for stroke diagnostics. EVs are known to reflect the immediate state of the secreting cells and to be able to cross the blood–brain barrier, thus making them attractive as diagnostic biomarkers of brain diseases. Indeed, several studies have reported EV markers that enable differentiation between stroke patients and controls and, to a lesser extent, the ability to correctly classify the different stroke types. Most of the studies rely on the use of sophisticated and time-consuming methods to quantify specific subpopulations of the nanosized EVs. As these methods cannot be easily implemented in a rapid point of care (POC) test, technical developments followed by prospective clinical studies are needed.

Endothelial Dysfunction in Chronic Kidney Disease, from Biology to Clinical Outcomes: A 2020 Update

The vascular endothelium is a dynamic, functionally complex organ, modulating multiple biological processes, including vascular tone and permeability, inflammatory responses, thrombosis, and angiogenesis. Endothelial dysfunction is a threat to the integrity of the vascular system, and it is pivotal in the pathogenesis of atherosclerosis and cardiovascular disease. Reduced nitric oxide (NO) bioavailability is a hallmark of chronic kidney disease (CKD), with this disturbance being almost universal in patients who reach the most advanced phase of CKD, end-stage kidney disease (ESKD). Low NO bioavailability in CKD depends on several mechanisms affecting the expression and the activity of endothelial NO synthase (eNOS). Accumulation of endogenous inhibitors of eNOS, inflammation and oxidative stress, advanced glycosylation products (AGEs), bone mineral balance disorders encompassing hyperphosphatemia, high levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23), and low levels of the active form of vitamin D (1,25 vitamin D) and the anti-ageing vasculoprotective factor Klotho all impinge upon NO bioavailability and are critical to endothelial dysfunction in CKD. Wide-ranging multivariate interventions are needed to counter endothelial dysfunction in CKD, an alteration triggering arterial disease and cardiovascular complications in this high-risk population.

Effect of Physical Exercise on the Release of Microparticles with Angiogenic Potential

Cellular communication has a fundamental role in both human physiological and pathological states and various mechanisms are involved in the crosstalk between organs. Among these, microparticles (MPs) have an important involvement. MPs are a subtype of extracellular vesicles produced by a variety of cells following activation or apoptosis. They are normally present in physiological conditions, but their concentration varies in pathological states such as cardiovascular disease, diabetes mellitus, or cancer. Acute and chronic physical exercise are able to modify MPs amounts as well. Among various actions, exercise-responsive MPs affect angiogenesis, the process through which new blood vessels grow from pre-existing vessels. Usually, the neo vascular growth has functional role; but an aberrant neovascularization accompanies several oncogenic, ischemic, or inflammatory diseases. In addition, angiogenesis is one of the key adaptations to physical exercise and training. In the present review, we report evidence regarding the effect of various typologies of exercise on circulating MPs that are able to affect angiogenesis.

Oxidative Stress and New Pathogenetic Mechanisms in Endothelial Dysfunction: Potential Diagnostic Biomarkers and Therapeutic Targets

Cardiovascular diseases (CVD), including heart and pathological circulatory conditions, are the world's leading cause of mortality and morbidity. Endothelial dysfunction involved in CVD pathogenesis is a trigger, or consequence, of oxidative stress and inflammation. Endothelial dysfunction is defined as a diminished production/availability of nitric oxide, with or without an imbalance between endothelium-derived contracting, and relaxing factors associated with a pro-inflammatory and prothrombotic status. Endothelial dysfunction-induced phenotypic changes include up-regulated expression of adhesion molecules and increased chemokine secretion, leukocyte adherence, cell permeability, low-density lipoprotein oxidation, platelet activation, and vascular smooth muscle cell proliferation and migration. Inflammation-induced oxidative stress results in an increased accumulation of reactive oxygen species (ROS), mainly derived from mitochondria. Excessive ROS production causes oxidation of macromolecules inducing cell apoptosis mediated by cytochrome-c release. Oxidation of mitochondrial cardiolipin loosens cytochrome-c binding, thus, favoring its cytosolic release and activation of the apoptotic cascade. Oxidative stress increases vascular permeability, promotes leukocyte adhesion, and induces alterations in endothelial signal transduction and redox-regulated transcription factors. Identification of new endothelial dysfunction-related oxidative stress markers represents a research goal for better prevention and therapy of CVD. New-generation therapeutic approaches based on carriers, gene therapy, cardiolipin stabilizer, and enzyme inhibitors have proved useful in clinical practice to counteract endothelial dysfunction. Experimental studies are in continuous development to discover new personalized treatments. Gene regulatory mechanisms, implicated in endothelial dysfunction, represent potential new targets for developing drugs able to prevent and counteract CVD-related endothelial dysfunction. Nevertheless, many challenges remain to overcome before these technologies and personalized therapeutic strategies can be used in CVD management.

Changes in circulating endothelial microvesicles in men after myocardial infarction

PURPOSE

The objective of the study was to determine the differences in the numbers of endothelial microvesicles (EMV) after myocardial infarction (MI) and their association with oxidative stress.

MATERIALS AND METHODS

We included 15 post MI patients and 28 healthy controls. Samples were analysed by flow cytometry. We examined four EMV populations: 1) CD144+, CD42a-, CD61^-, 2) CD144+, CD42a+, CD61^-, 3) CD105+, CD42a-, CD61^-and 4) CD31⁺, CD42a-, CD61^-and determined a percentage of CD62e + EMV. Malondialdehyde concentration was determined by ultra-high performance liquid chromatography.

RESULTS

The median of EMV counts differed between controls and patients in: CD105+ (10.91 microvesicles/μl vs. 33.68 microvesicles/μl, P = 0.006), CD144+, CD42a+ (312.87 microvesicles/μl vs. 73.29 microvesicles/μl, P < 0.001) and CD31⁺ (2 microvesicles/μl vs. 1.38 microvesicles/μl, P = 0.021). The median of percentage of CD62e expression differed between controls and patients in: CD105+ (1.35% vs. 14.8%, P < 0.001), CD144+, CD42a+ (56.45% vs. 98.99%, P < 0.001) and CD144+, CD42a- (173.03% vs. 215.56%) EMV. In patients, EMV counts correlated with low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) concentrations: CD105+: R = -0.69, P = 0.004 (LDL-C), R = -0.64, P = 0.01 (TC); CD144+, CD42a-: R = -0.68, P = 0.005 (LDL-C), R = -0.63, P = 0.011 (TC); CD144+: R = -0.54, P = 0.038 (HDL-C) and CD144+, CD42a-, CD62e+: R = 0.78, P = 0.001 (HDL-C). In controls, HDL-C concentration correlated with CD105+ (R = -0.395, P = 0.038) and CD105+, CD62e+ (R = -0.716, P < 0.001) counts. Malondialdehyde concentration correlated with CD144+, CD42a- (P = 0.01, R = 0.48) and CD105+, CD62e+ (P = 0.012, R = 0.47) counts.

CONCLUSIONS

Changes in EMV levels after the MI period were observed. Counts of EMV and their CD62e expression correlated with dyslipidaemia and oxidative stress.

Increased microparticle levels in middle-aged and elderly patients with insomnia may be involved in the pathogenesis of arteriosclerosis

BACKGROUND

Insomnia may affect vascular factors and promote arteriosclerosis. Microparticles (MPs) are a heterogeneous group of bioactive small vesicles that can be found in blood and body fluids following activation, necrosis or apoptosis of virtually any eukaryotic cells. MPs are believed to participate in the pathogenesis of atherosclerosis. Few studies have been concerned with the microparticle level in patients with sleep disorder. The purpose of the present study is to measure the levels of endothelial microparticles (EMPs), platelet microparticles (PMPs) and leukocyte-derived microparticles (LMPs) in middle-aged and elderly patients with or without insomnia.

METHODS

Patients with insomnia (N.=30) and without insomnia (N.=18) were enrolled. The insomnia group covered patients with chronic insomnia (N.=16) and acute insomnia (N.=14). Levels of EMPs (CD31 +, CD62E +) and PMPs (CD41a +, CD42a +) and granulocyte-derived (CD11a +) MPs were measured. Flow cytometry was performed on the Beckman Coulter analyzer. Reference gate was defined for the level of MPs using 0.22-0.45-0.88μm microspheres, and the size gate for MPs was 0.5-1.0μm.

RESULTS

Of all types of MPs detected, the levels of CD31 +MPs, CD62E +MPs and CD11a +MPs were significantly higher in the insomnia group than in the non-insomnia group (P<0.05). Besides, compared with acute insomnia, the levels of CD31 + MPs and CD11a +MPs were significantly higher in chronic insomnia (P<0.001).

CONCLUSIONS

In insomnia patients, atherosclerosis progression may be increased by the CD31+ EMPs-mediated apoptosis and endothelial injury. The level of CD11a+ LMPs kept increasing as insomnia persisted, which may indicate atherosclerosis progression.

Acute Exercise in Hypobaric Hypoxia Attenuates Endothelial Shedding in Subjects Unacclimatized to High Altitudes

Travel of unacclimatized subjects to a high altitude has been growing in popularity. Changes in endothelial shedding [circulating endothelial cells (ECs)] and hematopoietic stem and progenitor cells (CPCs) during physical exercise in hypobaric hypoxia, however, are not well understood. We investigated the change in ECs and CPCs when exposed to high altitude, after acute exercise therein, and after an overnight stay in hypobaric hypoxia in 11 healthy unacclimatized subjects. Blood withdrawal was done at baseline (520 m a.s.l.; baseline), after passive ascent to 3,883 m a.s.l. (arrival), after acute physical exercise (±400 m, postexercise) and after an overnight stay at 3,883 m a.s.l. (24 h). Mature blood cells, ECs, and CPCs were assessed by a hematology analyzer and flow cytometry, respectively. The presence of matrix metalloproteinases (MMPs), their activity, and hematopoietic cytokines were assessed in serum and plasma. EC and CPC concentrations significantly decreased after exercise (p = 0.019, p = 0.007, respectively). CPCs remained low until the next morning (24 h, p = 0.002), while EC concentrations returned back to baseline. MMP-9 decreased at arrival (p = 0.021), stayed low postexercise (p = 0.033), and returned to baseline at 24 h (p = 0.035 to postexercise). MMP-activity did not change throughout the study. Circulating MMP-9 concentrations, but not MMP-activity, were associated with EC concentrations (r_rm = 0.48, p = 0.010). CPC concentrations were not linked to hematopoietic cytokines. Acute exercise at high altitude attenuated endothelial shedding, but did not enhance regenerative CPCs. Results were not linked to endothelial matrix remodeling or CPC mobilization. These results provide information to better understand the endothelium and immature immune system during an active, short-term sojourn at high altitude.

Association between Upper-airway Surgery and Ameliorative Risk Markers of Endothelial Function in Obstructive Sleep Apnea

The objective of our study was to evaluate the effects of upper-airway surgery on improvement of endothelial function-related markers in patients with obstructive sleep apnea (OSA). Subjects with moderate to severe OSA who underwent upper-airway surgery, with a follow-up duration of at least 6 months, were included. Pre- and postoperative polysomnographic variables and endothelial function-related markers were compared. Subgroup and correlation analyses were conducted to find possible indicators for better endothelial function-related markers after upper-airway surgery. In total, 44 patients with OSA were included. The mean follow-up duration was 1.72 ± 0.92 years. Serum VEGFA [-20.29 (CI: -35.27, -5.31), p < 0.05], Ang2 [-0.06 (CI: -0.16, 0.03), p < 0.05], E-selectin [-7.21 (CI: -11.01, -3.41), p < 0.001], VWF [-58.83 (CI: -103.93, -13.73), p < 0.05], VWFCP [-33.52 (CI: -66.34, -0.70), p < 0.05], and TM [-0.06 (CI: -0.09, -0.03), p < 0.05] were significantly lower after upper-airway surgery. However, other risk markers of endothelial function, such as Ang1, ICAM1, VEGFR1, and VCAM, did not change significantly. Correlations between improved endothelial function-related markers and ameliorated oxyhemoglobin saturation and glucolipid metabolism were established. Upper-airway surgery might be associated with an improvement in endothelial function in patients with OSA. These changes may be associated with improved oxygen saturation after upper-airway surgery.

Loss of Renal Peritubular Capillaries in Hypertensive Patients Is Detectable by Urinary Endothelial Microparticle Levels

Hypertension, an important cause of chronic kidney disease, is characterized by peritubular capillary (PTC) loss. Circulating levels of endothelial microparticles (EMPs) reflect systemic endothelial injury. We hypothesized that systemic and urinary PTC-EMPs levels would reflect renal microvascular injury in hypertensive patients. We prospectively measured by flow cytometry renal vein, inferior vena cava, and urinary levels of EMPs in essential (n=14) and renovascular (RVH; n=24) hypertensive patients and compared them with peripheral blood and urinary levels in healthy volunteers (n=14). PTC-EMPs were identified as urinary exosomes positive for the PTC marker plasmalemmal-vesicle-associated protein. In 7 RVH patients, PTC and fibrosis were also quantified in renal biopsy, and in 18 RVH patients, PTC-EMPs were measured again 3 months after continued medical therapy with or without stenting (n=9 each). Renal vein and systemic PTC-EMPs levels were not different among the groups, whereas their urinary levels were elevated in both RVH and essential hypertension versus healthy volunteers (56.8%±12.7% and 62.8%±10.7% versus 34.0%±17.8%; both P≤0.001). Urinary PTC-EMPs levels correlated directly with blood pressure and inversely with estimated glomerular filtration rate. Furthermore, in RVH, urinary PTC-EMPs levels correlated directly with stenotic kidney hypoxia, histological PTC count, and fibrosis and inversely with cortical perfusion. Three months after treatment, the change in urinary PTC-EMPs levels correlated inversely with a change in renal function ( r=-0.582; P=0.011). Therefore, urinary PTC-EMPs levels are increased in hypertensive patients and may reflect renal microcirculation injury, whereas systemic PTC-EMPs levels are unchanged. Urinary PTC-EMPs may be useful as novel biomarkers of intrarenal capillary loss.

Circulating microparticles as biomarkers of stroke: A focus on the value of endothelial- and platelet-derived microparticles

Stroke is one of the leading causes of mortality and disability worldwide. Numerous pathophysiological mechanisms involving blood vessels, coagulation and inflammation contribute to the vascular occlusion. Perturbations in these pathways can be detected by numerous methods including changes in endoplasmic membrane remodeling and rearrangement leading to the shedding of microparticles (MPs) from various cellular origins in the blood. MPs are small membrane-derived vesicles that are shed from nearly all cells in the body in resting state or upon stimulation. MPs act as biological messengers to transfer information to adjacent and distant cells thus regulating various biological processes. MPs may be important biomarkers and tools for the identification of the risk and diagnosis of cerebrovascular diseases. Endothelial activation and dysfunction and altered thrombotic responses are two of the main features predisposing to stroke. Endothelial MPs (EMPs) have been recognized as both biomarkers and effectors of endothelial cell activation and injury while platelet-derived MPs (PMPs) carry a strong procoagulant potential and are activated in thrombotic states. Therefore, we reviewed here the role of EMPs and PMPs as biomarkers of stroke. Most studies reported high circulating levels of EMPs and PMPs in addition to other cell origins in stroke patients and have been linked to stroke severity, the size of infarction, and prognosis. The identification and quantification of EMPs and PMPs may thus be useful for the diagnosis and management of stroke.

Large Extracellular Vesicles: Have We Found the Holy Grail of Inflammation?

The terms microparticles (MPs) and microvesicles (MVs) refer to large extracellular vesicles (EVs) generated from a broad spectrum of cells upon its activation or death by apoptosis. The unique surface antigens of MPs/MVs allow for the identification of their cellular origin as well as its functional characterization. Two basic aspects of MP/MV functions in physiology and pathological conditions are widely considered. Firstly, it has become evident that large EVs have strong procoagulant properties. Secondly, experimental and clinical studies have shown that MPs/MVs play a crucial role in the pathophysiology of inflammation-associated disorders. A cardinal feature of these disorders is an enhanced generation of platelets-, endothelial-, and leukocyte-derived EVs. Nevertheless, anti-inflammatory effects of miscellaneous EV types have also been described, which provided important new insights into the large EV-inflammation axis. Advances in understanding the biology of MPs/MVs have led to the preparation of this review article aimed at discussing the association between large EVs and inflammation, depending on their cellular origin.

Effect of exercise on the plasma vesicular proteome: a methodological study comparing acoustic trapping and centrifugation

Extracellular vesicles (EVs) are a heterogeneous group of actively released vesicles originating from a wide range of cell types. Characterization of these EVs and their proteomes in the human plasma provides a novel approach in clinical diagnostics, as they reflect physiological and pathological states. However, EV isolation is technically challenging with the current methods having several disadvantages, requiring large sample volumes, and resulting in loss of sample and EV integrity. Here, we use an alternative, non-contact method based on a microscale acoustic standing wave technology. Improved coupling of the acoustic resonator increased the EV recovery from 30% in earlier reports to 80%, also displaying long term stability between experiment days. We report a pilot study, with 20 subjects who underwent physical exercise. Plasma samples were obtained before and 1 h after the workout. Acoustic trapping was compared to a standard high-speed centrifugation protocol, and the method was validated by flow cytometry (FCM). To monitor the device stability, the pooled frozen plasma from volunteers was used as an internal control. A key finding from the FCM analysis was a decrease in CD62E+ (E-selectin) EVs 1 h after exercise that was consistent for both methods. Furthermore, we report the first data that analyse differential EV protein expression before and after physical exercise. Olink-based proteomic analysis showed 54 significantly changed proteins in the EV fraction in response to physical exercise, whereas the EV-free plasma proteome only displayed four differentially regulated proteins, thus underlining an important role of these vesicles in cellular communication, and their potential as plasma derived biomarkers. We conclude that acoustic trapping offers a fast and efficient method comparable with high-speed centrifugation protocols. Further, it has the advantage of using smaller sample volumes (12.5 μL) and rapid contact-free separation with higher yield, and can thus pave the way for future clinical EV-based diagnostics.

Endothelial microvesicles in hypoxic hypoxia diseases

Hypoxic hypoxia, including abnormally low partial pressure of inhaled oxygen, external respiratory dysfunction-induced respiratory hypoxia and venous blood flow into the arterial blood, is characterized by decreased arterial oxygen partial pressure, resulting in tissue oxygen deficiency. The specific characteristics include reduced arterial oxygen partial pressure and oxygen content. Hypoxic hypoxia diseases (HHDs) have attracted increased attention due to their high morbidity and mortality and mounting evidence showing that hypoxia-induced oxidative stress, coagulation, inflammation and angiogenesis play extremely important roles in the physiological and pathological processes of HHDs-related vascular endothelial injury. Interestingly, endothelial microvesicles (EMVs), which can be induced by hypoxia, hypoxia-induced oxidative stress, coagulation and inflammation in HHDs, have emerged as key mediators of intercellular communication and cellular functions. EMVs shed from activated or apoptotic endothelial cells (ECs) reflect the degree of ECs damage, and elevated EMVs levels are present in several HHDs, including obstructive sleep apnoea syndrome and chronic obstructive pulmonary disease. Furthermore, EMVs have procoagulant, proinflammatory and angiogenic functions that affect the pathological processes of HHDs. This review summarizes the emerging roles of EMVs in the diagnosis, staging, treatment and clinical prognosis of HHDs.

Extracellular vesicles: mediators and biomarkers of pathology along CNS barriers

Extracellular vesicles (EVs) are heterogeneous, nano-sized vesicles that are shed into the blood and other body fluids, which disperse a variety of bioactive molecules (e.g., protein, mRNA, miRNA, DNA and lipids) to cellular targets over long and short distances. EVs are thought to be produced by nearly every cell type, however this review will focus specifically on EVs that originate from cells at the interface of CNS barriers. Highlighted topics include, EV biogenesis, the production of EVs in response to neuroinflammation, role in intercellular communication and their utility as a therapeutic platform. In this review, novel concepts regarding the use of EVs as biomarkers for BBB status and as facilitators for immune neuroinvasion are also discussed. Future directions and prospective are covered along with important unanswered questions in the field of CNS endothelial EV biology.

Iso-Osmolar Iodixanol Induces Less Increase in Circulating Endothelial Microparticles In Vivo and Less Endothelial Apoptosis In Vitro Compared with Low-Osmolar Iohexol

Background and Aims

There is no consensus on whether iodixanol is superior to iohexol. This study aimed to compare the effects of iodixanol and iohexol on circulating endothelial microparticles (EMPs) in stable coronary artery disease (CAD) patients with diabetes mellitus (DM), and also their cytotoxic effects on human umbilical vein endothelial cells (HUVECs) in vitro.

Methods

100 CAD patients with DM were randomly assigned to receive iso-osmolar contrast medium iodixanol (group I) or low-osmolar iohexol (group II) during coronary angioplasty. An additional 49 CAD patients without DM receiving iohexol were recruited as group III. Circulating CD31+/CD41a- EMPs, CD62E+ EMPs, and CD31+/CD41a+ platelet microparticles (PMPs) were determined by flow cytometry. In vitro, the cytotoxic effects of iodixanol and iohexol on HUVECs were determined.

Results

Circulating CD31+/CD41a- EMPs and PMPs were significantly increased after angioplasty in all 3 groups, while CD62E+ EMPs significantly decreased in group I. CD31+/CD41a- EMPs and PMPs were significantly higher in group II than group I or III. In vitro, both contrast media induced EMP release and inhibited the viability and induced apoptosis of HUVECs, as well as increasing Bax and cleaved caspase-3 and decreasing Bcl-2. The above effects were less evident in iodixanol than in iohexol.

Conclusions

Compared with iohexol, iodixanol induces less release of EMPs in both CAD patients with DM during angioplasty and in vitro HUVEC culture, which is associated with less pronounced proapoptotic effects of iodixanol on HUVECs.

Clinical Study Registration Number

This study is registered with ChiCTR-TRC-14005183.

Recent advances in pathophysiology of disseminated intravascular coagulation: the role of circulating histones and neutrophil extracellular traps

Disseminated intravascular coagulation (DIC) is an acquired condition that develops as a complication of systemic and sustained cell injury in conditions such as sepsis and trauma. It represents major dysregulation and increased thrombin generation in vivo. A poor understanding and recognition of the complex interactions in the coagulation, fibrinolytic, inflammatory, and innate immune pathways have resulted in continued poor management and high mortality rates in DIC. This review focuses attention on significant recent advances in our understanding of DIC pathophysiology. In particular, circulating histones and neutrophil extracellular traps fulfil established criteria in DIC pathogenesis. Both are damaging to the vasculature and highly relevant to the cross talk between coagulation and inflammation processes, which can culminate in adverse clinical outcomes. These molecules have a strong potential to be novel biomarkers and therapeutic targets in DIC, which is still considered synonymous with 'death is coming'.