Levels Of Endothelial Cell-derived Microparticles Research Articles

Microparticles: potential new contributors to the pathogenesis of systemic sclerosis?

BackgroundMicroparticles (MPs) are membrane-derived vesicles released from cells undergoing activation or apoptosis with diverse proinflammatory and prothrombotic activities, that have been implicated in the pathogenesis of systemic sclerosis (SSc). We aimed to evaluate the plasma levels of platelet-derived microparticles (PMPs), endothelial cell-derived microparticles (EMPs), and monocyte-derived microparticles (MMPs) in SSc patients, and the association between MPs and the clinical features of SSc.MethodsIn this cross-sectional study, 70 patients with SSc and 35 age- and sex-matched healthy controls were evaluated. Clinical and nailfold capillaroscopy (NFC) data were obtained from all patients. Plasma levels of PMPs (CD42+/31+), EMPs (CD105+), and MMPs (CD14+) were quantified by flow cytometry.ResultsPatients were mainly females (90%), with a mean age of 48.9 years old. PMP, EMP, and MMP levels were significantly increased in SSc patients compared to controls (79.2% ± 17.3% vs. 71.0% ± 19.8%, p = 0.033; 43.5% ± 8.7% vs. 37.8% ± 10.4%, p = 0.004; and 3.5% ± 1.3% vs. 1.1% ± 0.5%, p < 0.0001, respectively). PMP levels were significantly higher in patients with positive anti-topoisomerase-I antibodies (p = 0.030) and in patients with a disease duration > 3 years (p = 0.038). EMP levels were lower in patients with a higher modified Rodnan skin score (p = 0.015), and in those with an avascular score > 1.5 in NFC (p = 0.042).ConclusionThe increased levels of PMPs, EMPs and MMPs in scleroderma patients might indicate a possible role for these agents in the pathogenesis of this challenging disease.

Characterisation of circulating endothelial microparticles in Behçet's disease: new markers of chronic endothelial damage?

Endothelial cell-derived microparticles (EMPs) are directly indicative of endothelial cell activation or apoptosis, and may also reflect endothelial inflammation, increased coagulation, and vascular tone. The aim of this study is to investigate whether EMPs would be able to evaluate system involvement and be a new indicators of disease activity in Behçet's disease (BD). Thirty-nine consecutive BD patients (who fulfilled the modified 1990 International Study Group on Behçet's disease or the 2006 International Criteria for Behçet's Disease) and 30 age- and sex-matched healthy controls were enrolled. The plasma levels of EMPs were measured by flow cytometry utilising specific labels for endothelial MPs (CD31+ and CD42b-). The levels of circulating EMPs (CD31+ and CD42b-) were significantly elevated in the case group compared with the healthy control group (p =0.000). Moreover, BD patients plasma EMPs were positively correlated with BD current activity form (r=0.802, p =0.000). Vascular and gastrointestinal involvement in BD patients were significantly increased (p=0.004 and p=0.011, respectively) with respect to patients without vascular and gastrointestinal EMPs. Levels of circulating EMPs are elevated in BD patients and correlate with the disease activity; the elevated EMPs may be a potential indicator to predict disease activity of BD. The plasma level of EMPs was increased, which indicated the increased risk of vascular and digestive tract involvement in BD.

Efficacy of Different Fluid Resuscitation Methods on Coagulation Function of Rats with Traumatic Hemorrhagic Shock

BackgroundFluid resuscitation is widely used for treating traumatic hemorrhagic shock. We focused on the efficacies of different fluid resuscitation methods on improving coagulation function of traumatic hemorrhagic shock (THS) rats. Materials and methodsSprague-Dawley rats (n = 100) were randomly divided into 5 groups, namely, Sham group, THS group, acetic acid Ringer's fluid (AR) group, hydroxyethyl starch solution (HES) group, and AR + HES group. A THS rat model was established by left femoral bleeding. The effects of different fluid resuscitation methods on conventional coagulation function parameters, Rotational thromboelastometry parameters, platelet-derived microparticles and endothelial cell–derived microparticles content of the THS rats were detected by ACL TOP system, rotation thromboelastometry, and flow cytometry, respectively. ResultsUsing AR and HES alone had no significant effect on the coagulation function of THS rats, but the two in combination reduced the increases of thrombin time, prothrombin time, activated part thrombin time, international normalized ratio, fibrin degradation products, D-dimer and the decreases of platelet count and fibrinogen concentration induced by THS. The CT and CFT were significantly reduced, whereas α and MCF were increased in the THS rats in AR + HES group. The combination of AR and HES reversed the effect of THS on elevating platelet-derived microparticles and endothelial cell–derived microparticle levels. In addition, the coagulation was relatively the optimal in the AR, HES, and AR + HES groups when the mice were resuscitated to a mean arterial pressure of 60 mmHg. ConclusionsAR combined with HES has a significant protective effect on coagulation function of THS rats when the mean arterial pressure reaches 60 mmHg.

PAK4 suppresses TNF-induced release of endothelial microparticles in HUVECs cells.

Tumor necrosis factor-α (TNF) is a pro-inflammatory cytokine upregulated in many inflammatory diseases, and a potent inducer of endothelial cell-derived microparticle (EMP) formation. In this study, we identified the protein kinase PAK4 as a key regulator of the TNF-induced EMP release from human umbilical vein endothelial cells (HUVECs). TNF induces dose- and time-dependent EMP release and downregulation of PAK4 and upstream cdc42 in HUVECs. PAK4 suppression or inhibition of its kinase activity increases TNF-induced EMP release and apoptosis in HUVECs, while PAK4 overexpression reduces EMP release and apoptosis in TNF-stimulated cells. Collectively, these data indicate that PAK4 suppresses TNF-induced EMP generation occurring during apoptosis, and suggest that modulation of PAK4 activity may represent a novel approach to suppress the TNF-induced EMP levels in pro-inflammatory disorders and other pathological conditions.

Association of endothelial and red blood cell microparticles with acute myocardial infarction in Chinese: a retrospective study.

Mounting evidence suggests that endothelial cell-derived microparticles (EMPs) and red blood cell-derived microparticles (RMPs), which have procoagulant and vasoconstriction effects, are involved in the development of vascular acute cardiovascular events. The aim of this study was to analyze the circulating levels of EMPs and RMPs in patients with acute myocardial infarction (AMI), and to explore the correlations between EMPs and RMPs and the severity of coronary artery disease. Plasma samples from 110 patients with AMI and 57 non-coronary artery disease group (nonCAD) were collected in the present study. The flow cytometry was used to measure the EMPs (CD31) and RMPs (CD235a) qualitatively and quantitatively. The levels of EMPs and RMPs in the AMI group were higher than that in the Non-CAD group, yet no significant difference was found between STEMI and non-STEMI subjects. The levels of EMPs and RMPs in multi-vessel were higher than in the single-vessel l disease. In the Thrombolysis in Myocardial Infarction (TIMI) risk assessment, the levels of EMPs in the high-risk group were higher than that in both intermediate- and low-risk group. The low-risk group had the lowest EMP levels, the difference between the groups being statistically significant (P=0.001). No significant difference in RMP levels was noted upon TIMI stratification. According to the ROC curve analysis, the areas under the curve (AUC) of EMPs and RMPs were 0.706 and 0.668, respectively. The circulating levels of EMPs and RMPs in patients with AMI are elevated, and the level of EMPs is related to the degree of coronary artery disease and the prognosis risk. The EMPs are more likely to be potential biomarkers than RMPs to provide diagnostic value for AMI.

Longer Sleep Duration and Endothelial Cell Health Among a Multiethnic Sample of Adolescents.

Adverse endothelial cell health, an early pathogenic process underlying atherosclerosis and cardiovascular disease, is evident in childhood and adolescence. Sleep duration, a modifiable cardiovascular health behavior, may be an important cardiovascular disease prevention target that may affect endothelial cell health. We examined the associations of longer sleep duration with endothelial cell injury among youth. In a multiethnic sample of 235 children (63.0% female, mean age = 13.9 years), we conducted multivariable linear regressions to test the cross-sectional association of sleep duration and circulating levels of endothelial cell-derived microparticles (EMPs), phenotypic for endothelial cell activation and apoptosis (CD62E+ EMPs, CD31+/CD42b- EMPs, and CD31+/Annexin V+ EMPs). Sleep duration and EMPs were both treated as continuous variables. Models were adjusted for age, sex, race, pubertal status, household economic resources, and waist circumference. Overall, 69.2% had short sleep duration (<8 hours of sleep per night). Longer sleep duration was significantly associated with lower levels of CD62E+ EMPs and CD31+/CD42b- EMPs. A 60-minute increase in sleep duration was associated with an 8.40 (95% confidence interval = -205.20 to -1.80, p = .046) decrease in CD62E+ EMPs and a 9.00 (95% confidence interval = -153.60 to -9.60, p = .027) decrease in CD31+/CD42b- EMPs. Sleep duration was not associated with CD31+/Annexin V+ EMPs. Our results support the hypothesis that sleeping longer has beneficial effects on endothelial cell health during childhood. Primordial prevention efforts might incorporate sleep extension to offset cardiovascular risk in youth.

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

IntroductionThe experience of negative emotions (eg, anger, anxiety and sadness) is associated with an increased short-term risk of incident cardiovascular disease (CVD) events, independent of traditional CVD risk factors. Impairment...

Sustained apnea induces endothelial activation.

Apnea diving has gained worldwide popularity, even though the pathophysiological consequences of this challenging sport on the human body are poorly investigated and understood. This study aims to assess the influence of sustained apnea in healthy volunteers on circulating microparticles (MPs) and microRNAs (miRs), which are established biomarkers reflecting vascular function. Short intermittent hypoxia due to voluntary breath-holding affects circulating levels of endothelial cell-derived MPs (EMPs) and endothelial cell-derived miRs. Under dry laboratory conditions, 10 trained apneic divers performed maximal breath-hold. Venous blood samples were taken, once before and at 4 defined points in time after apnea. Samples were analyzed for circulating EMPs and endothelial miRs. Average apnea time was 329 seconds (±103), and SpO2 at the end of apnea was 79% (±12). Apnea was associated with a time-dependent increase of circulating endothelial cell-derived EMPs and endothelial miRs. Levels of circulating EMPs in the bloodstream reached a peak 4 hours after the apnea period and returned to baseline levels after 24 hours. Circulating miR-126 levels were elevated at all time points after a single voluntary maximal apnea, whereas miR-26 levels were elevated significantly only after 30 minutes and 4 hours. Also miR-21 and miR-92 levels increased, but did not reach the level of significance. Even a single maximal breath-hold induces acute endothelial activation and should be performed with great caution by subjects with preexisting vascular diseases. Voluntary apnea might be used as a model to simulate changes in endothelial function caused by hypoxia in humans.

Prevention of Stress-Provoked Endothelial Injury by Values Affirmation: a Proof of Principle Study.

Background Few studies have tested whether cellular processes directly associated with cardiovascular disease risk can be influenced by a psychological inoculation. Purpose This study investigated whether values affirmation, a psychological procedure designed to reduce stress and threat perception, would prevent endothelial injury to social evaluative threat (SET). Methods Participants (N=32) were randomized to SET, SET with values affirmation, or Control. SET was induced with the Trier Social Stress Test, and participants performed values affirmation prior to SET induction. Using flow cytometry, endothelial injury was assessed by measuring circulating levels of endothelial cell-derived microparticles (EMPs) phenotypic for endothelial cell activation (CD62E+), apoptosis (CD31+) or both (CD51+). Results Social threat caused expected increases in circulating EMPs phenotypic of endothelial cell injury, a response completely attenuated in those receiving values affirmation. Conclusions This study, as proof of principle due to small sample size, shows cellular level, cardiovascular disease-relevant effects of social stress and provides the first evidence of inoculation against such effects by a psychological procedure.

Role of tumour necrosis factor receptor-1 and nuclear factor-κB in production of TNF-α-induced pro-inflammatory microparticles in endothelial cells.

Tumour necrosis factor-α (TNF-α) is upregulated in many inflammatory diseases and is also a potent agent for microparticle (MP) generation. Here, we describe an essential role of TNF-α in the production of endothelial cell-derived microparticles (EMPs) in vivo and the function of TNF-α-induced EMPs in endothelial cells. We found that TNF-α rapidly increased blood levels of EMPs in mice. Treatment of human umbilical vein endothelial cells (HUVECs) with TNF-α also induced EMP formation in a time-dependent manner. Silencing of TNF receptor (TNFR)-1 or inhibition of the nuclear factor-κB (NF-κB) in HUVECs impaired the production of TNF-α-induced EMP. Incubation of HUVECs with PKH-67-stained EMPs showed that endothelial cells readily engulfed EMPs, and the engulfed TNF-α-induced EMPs promoted the expression of pro-apoptotic molecules and upregulated intercellular adhesion molecule-1 level on the cell surface, which led to monocyte adhesion. Collectively, our findings indicate that the generation of TNF-α-induced EMPs was mediated by TNFR1 or NF-κB and that EMPs can contribute to apoptosis and inflammation of endothelial cells.

Elevated Levels of Endothelial Cell-Derived Microparticles following Short-Term Withdrawal of Continuous Positive Airway Pressure in Patients with Obstructive Sleep Apnea: Data from a Randomized Controlled Trial

Background: Obstructive sleep apnea has been associated with impaired endothelial function; however, the mechanisms underlying this association are not completely understood. Cell-derived microparticles may provide a link between obstructive sleep apnea and endothelial dysfunction. Objectives: This randomized controlled trial aimed to examine the effect of a 2-week withdrawal of continuous positive airway pressure (CPAP) therapy on levels of circulating microparticles. Methods: Forty-one obstructive sleep apnea patients established on CPAP treatment were randomized to either CPAP withdrawal (subtherapeutic CPAP) or continuing therapeutic CPAP, for 2 weeks. Polysomnography was performed and circulating levels of microparticles were analyzed by flow cytometry at baseline and 2 weeks. Results: CPAP withdrawal led to a recurrence of obstructive sleep apnea. Levels of CD62E+ endothelium-derived microparticles increased significantly in the CPAP withdrawal group compared to the continuing therapeutic CPAP group (median difference in change +32.4 per µl; 95% CI +7.3 to +64.1 per µl, p = 0.010). CPAP withdrawal was not associated with a statistically significant increase in granulocyte, leukocyte, and platelet-derived microparticles when compared with therapeutic CPAP. Conclusions: Short-term withdrawal of CPAP therapy leads to a significant increase in endothelium-derived microparticles, suggesting that microparticle formation may be causally linked to obstructive sleep apnea and may promote endothelial activation.

Hormone replacement therapy leads to increased plasma levels of platelet derived microparticles in postmenopausal women

Whereas prevention of cardiovascular diseases by hormonal replacement therapy is still part of an ongoing debate, well-defined data are available relating hormonal replacement therapy to an elevated risk of venous thrombosis and embolism. Although it seems that venous thrombosis in patients treated with hormonal replacement therapy is linked to changes in plasmatic coagulation, less is known about the role of platelet-derived microparticles, as well as endothelial cell-derived microparticles. In this prospective case-control study, levels of microparticles were investigated in postmenopausal women receiving hormone replacement therapy (n = 15) and compared to age-matched controls (n = 15). Total count of microparticles and the subgroup of microparticles derived from endothelial cells did not differ in the investigated groups. In contrast, median levels of microparticles derived from platelet/megacaryocyte were higher in women taking hormonal replacement therapy (5,244 × 10(6)/l) than in controls (2,803 × 10(6)/l; p = 0.040). Furthermore, hormonal replacement therapy led to a higher plasma level of microparticles derived from activated platelets, exposing P-selectin (136 × 10(6)/l vs. 58 × 10(6)/l; p = 0.011), or exposing CD63 (171 × 10(6) vs. 91 × 10(6)/l; p = 0.011) compared to the control group. Higher concentrations of microparticles derived from (activated) platelets/megacaryocytes were present in postmenopausal women taking hormonal replacement therapy. This finding indicates a procoagulant state in these women and might play a role in the development of venous side effects. In contrast, levels of endothelial cell-derived microparticles did not differ.

Circulating cell-derived microparticles in patients with minimally symptomatic obstructive sleep apnoea

Moderate-severe obstructive sleep apnoea (OSA) has been associated with several pro-atherogenic mechanisms and increased cardiovascular risk, but it is not known if minimally symptomatic OSA has similar effects. Circulating cell-derived microparticles have been shown to have pro-inflammatory, pro-coagulant and endothelial function-impairing effects, as well as to predict subclinical atherosclerosis and cardiovascular risk. In 57 patients with minimally symptomatic OSA, and 15 closely matched control subjects without OSA, AnnexinV-positive, platelet-, leukocyte- and endothelial cell-derived microparticles were measured by flow cytometry. In patients with OSA, median (interquartile range) levels of AnnexinV-positive microparticles were significantly elevated compared with control subjects: 2,586 (1,566-3,964) microL(-1) versus 1,206 (474-2,501) microL(-1), respectively. Levels of platelet-derived and leukocyte-derived microparticles were also significantly higher in patients with OSA (2,267 (1,102-3,592) microL(-1) and 20 (14-31) microL(-1), respectively) compared with control subjects (925 (328-2,068) microL(-1) and 15 (5-23) microL(-1), respectively). Endothelial cell-derived microparticle levels were similar in patients with OSA compared with control subjects (13 (8-25) microL(-1) versus 11 (6-17) microL(-1)). In patients with minimally symptomatic obstructive sleep apnoea, levels of AnnexinV-positive, platelet- and leukocyte-derived microparticles are elevated when compared with closely matched control subjects without obstructive sleep apnoea. These findings suggest that these patients may be at increased cardiovascular risk, despite being minimally symptomatic.

Platelet and endothelial cell-derived microparticles in steroid-induced osteonecrosis of the femoral head of rabbit model

To explore the relationship between the alterations of platelet-derived microparticles (PMPs) and endothelial cell-derived microparticles (EMPs) and steroid-induced osteonecrosis of the femoral head. Forty-four adult Japanese white rabbits were randomly divided into 2 groups: experimental group (n = 44), injected intramuscularly once with 20 mg/kg of methylprednisolone acetate, and control group (n = 28) injected with normal saline of the same dose. Blood samples were collected from the auricular vein while the animals were in a fasting state in early morning prior to experiment (week 0), and 2, 4, and 8 weeks after the injection. The levels of prothrombin time (PT), activated partial prothrombin time (APTT), and anti-thrombokinase-III (AT-III) were examined. Plasma was ultra-centrifuged and the circulating platelet and EMPs were isolated to undergo flow cytometry to detect the amounts of CD31, CD42a, CD54, and CD62E. 1, 2, 4, and 8 week after the injection 6 rabbits from the experimental group and 4 rabbits from the control group were sacrificed respectively and their femoral heads were taken out to undergo histopathologic examination with HE staining and microthrombus and elastic fiber staining. The PT, APTT, and AT-III levels increased significantly 1 to 8 weeks after the injection. The numbers of EMPs and PMPs were also increased markedly after steroid administration. Histopathologic examination demonstrated an accumulation of bone marrow cell debris, presence bone empty lacunae in the trabeculae 1 week after the steroid injection. 2, 4, and 8 weeks after the steroid injection the bone necrosis was remarkable, fatty degeneration of bone marrow cells occurred, the diameter of fat cells increased, and the area ratio of fatty cells became higher. MSB staining was positive. High dose glucocorticosteroid increases the levels of PMPs and EMPs that may be related to hypercoagulability and thrombosis in microcirculation and play an important role in steroid-induced osteonecrosis. MP can be considered a true target in the pharmacological control of steroid-induced osteonecrosis.

Endothelial Cell–Derived Microparticles in Allogeneic Hematopoietic Stem Cell Recipients

Alterations of microparticles derived from different cell types are described in a number of diseases associated with inflammation and hemostatic disorders. In this prospective study, we firstly analyzed endothelial cell derived microparticles (EMP) in 19 hematopoietic stem cell recipients. Cultured human umbilical vein endothelial cells (HUVEC) stimulated with tumor necrosis factor-alpha (TNF-alpha) served as positive controls. EMP were analyzed by fluorescent activated cell sorting (FACS), detecting the particels via expression of CD62 (E-selectin) and anionic phospholipids binding to annexin V. EMP were not significantly influenced by conditioning regimens with non-myeloablative chemotherapy and 4 Gy total body irradiation (TBI) or by myeloablative regimens containing 12 Gy TBI. During acute graft versus host disease (aGVHD), significantly higher levels of EMP were detected than in patients without aGVHD (18.5/microl s=10.1 vs. 14.6/microl SD = 11.5; P = 0.004) while infectious complications did not alter EMP levels significantly. Immunosuppressive therapy with corticosteroids tendentially elevated EMP levels. HUVEC treated with TNF-alpha 1 ng/ml, 10 ng/ml and 100 ng/ml released significantly more EMP than unstimulated cultures (30.0/microl ss = 13.6 vs. 126.8/microl SD = 66.9, P = 0.032 / vs. 683.3/microl SD = 349.9; P = 0.03 / vs. 489.3 s = 184.4; P = 0.013). Elevation of EMP during aGVHD might express severe endothelial cell injury within this complication after hematopoietic stem cell transplantation and might serve as a diagnostic test for early differentiation of aGVHD from other transplanted related complications.