CD144+EMPs/CD62E+EMPs: A couple of new biomarkers to monitor endothelial function in hypertension with hyperlipidemia involved

Platelet-derived extracellular vesicles correlate with therapy-induced nocturnal blood pressure changes

INTRODUCTION

Elevated nocturnal blood pressure (BP) is closely associated with increased risk of cardiovascular (CV) events. Circulating extracellular vesicles (EVs) have been proposed as a potential CV risk biomarker and shown to correlate with BP. The present study aimed to assess whether a reduction in BP is paralleled by respective changes in EVs.

METHODS

Fifty-five hypertensive patients (age: 57.7 ± 14.1 years) were included in the study. EVs and BP were assessed at baseline and at 12 weeks follow-up. Interventions to lower BP included advice on life-style modification only or life-style advice combined with additional pharmacotherapy. EVs were evaluated by flow cytometry (CD41+/Annexin V+) and BP by unobserved automated office BP and ambulatory BP monitoring.

RESULTS

Nocturnal systolic BP correlated with EV levels at baseline ( P  = 0.01). Multivariable regression models showed that changes in nocturnal systolic BP (adjusted R2  = 0.23; P  = 0.01) and diastolic BP (adjusted R2  = 0.18; P  = 0.02) were associated with respective changes in EV levels. Furthermore, intervention-induced improvement of systolic dipping was associated with a reduction in EVs in the univariate analysis (adjusted R2  = 0.06; P  = 0.03). In contrast, systolic office, 24 h- and daytime-BP did not show significant associations with EVs. Patients whose medication was up-titrated at baseline showed a trend towards lower EV levels at follow-up (absolute change of -1.7 ± 1.3 EV/μl; P  = 0.057).

CONCLUSIONS

Circulating platelet-derived EVs were positively associated with nocturnal BP and therapy-induced changes over a 12-week treatment period. EVs may provide an integrated measure of BP changes achieved with pharmacotherapy.

Circulating platelet-derived extracellular vesicles correlate with night-time blood pressure and vascular organ damage and may represent an integrative biomarker of vascular health

Elevated office blood pressure (BP) has previously been associated with increased levels of circulating extracellular vesicles (EVs). The present study aimed to assess the relationship between levels of platelet derived EVs, ambulatory BP parameters, and pulse wave velocity as a marker of macrovascular organ damage. A total of 96 participants were included in the study. Platelet-derived extracellular vesicles (pEVs) were evaluated by flow cytometry (CD41+/Annexin v+). BP evaluation included unobserved automated office BP and ambulatory BP monitoring. Carotid-femoral pulse wave velocity (PWV) was measured as a marker of macrovascular damage. pEVs correlated with nocturnal systolic BP (r = 0.31; p = .003) and nocturnal dipping (r = -0.29; p = .01) in univariable analysis. Multivariable regression models confirmed robustness of the association of EVs and nocturnal blood pressure (p = .02). In contrast, systolic office, 24h- and daytime-BP did not show significant associations with pEVs. No correlations were found with diastolic BP. Circulating pEVs correlated with pulse wave velocity (r = 0.25; p = .02). When comparing different hypertensive phenotypes, higher levels of EVs and PWV were evident in patients with sustained hypertension compared to patients with white coat HTN and healthy persons. Circulating platelet derived EVs were associated with nocturnal BP, dipping, and PWV. Given that average nocturnal BP is the strongest predictor of CV events, platelet derived EVs may serve as an integrative marker of vascular health, a proposition that requires testing in prospective clinical trials.

A study of endothelial and platelet microvesicles across different hypertension phenotypes

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

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

BACKGROUND

Fluid 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 METHODS

Sprague-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.

RESULTS

Using 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.

CONCLUSIONS

AR combined with HES has a significant protective effect on coagulation function of THS rats when the mean arterial pressure reaches 60 mmHg.

Extracellular Vesicles in Essential Hypertension: Hidden Messengers

PURPOSE OF REVIEW

Hypertension affects about half of all Americans, yet in the vast majority of cases, the factors causing the hypertension cannot be clearly delineated. Developing a more precise understanding of the molecular pathogenesis of HTN and its various phenotypes is therefore a pressing priority. Circulating and urinary extracellular vesicles (EVs) are potential novel candidates as biomarkers and bioactivators in HTN. EVs are a heterogeneous population of small membrane fragments shed from various cell types into various body fluids. As EVs carry protein, RNA, and lipids, they also play a role as effectors and novel cell-to-cell communicators. In this review, we discuss the diagnostic, functional, and regenerative role of EVs in essential HTN and focus on EV protein and RNA cargo as the most extensively studied EV cargo.

RECENT FINDINGS

The field of EVs in HTN is still a young one and earlier studies have not used the novel EV detection tools currently available. More rigor and transparency in EV research are needed. Current data suggest that EVs represent potential novel biomarkers in HTN. EVs correlate with HTN severity and possibly end-organ damage. However, it has yet to be discerned which specific subtype(s) of EV reflects best HTN pathophysiology. Evolving studies are also showing that EVs might be novel regulators in vascular and renal tubular function and also be therapeutic. RNA in EVs has been studied in the context of hypertension, largely in the form of studies of miRNA, which are reviewed herein. Beyond miRNAs, mRNA in urinary EVs changed in response to sodium loading in humans. EVs represent promising novel biomarkers and bioactivators in essential HTN. Novel tools are being developed to apply more rigor in EV research including more in vivo models and translation to humans.

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.

Shear stress-mediated upregulation of GTP cyclohydrolase/tetrahydrobiopterin pathway ameliorates hypertension-related decline in reendothelialization capacity of endothelial progenitor cells

OBJECTIVES

Guanosine triphosphate cyclohydrolase/tetrahydrobiopterin (GTPCH)/(BH4) pathway has been proved to regulate the function of endothelial progenitor cells (EPCs) in deoxycorticosterone acetate-salt hypertensive mice, indicating that GTPCH/BH4 pathway may be an important repair target for hypertension-related endothelial injury. Shear stress is an important nonpharmacologic strategy to modulate the function of EPCs. Here, we investigated the effects of laminar shear stress on the GTPCH/BH4 pathway and endothelial repair capacity of circulating EPCs in hypertension.

METHOD

Laminar shear stress was loaded on the human EPCs from hypertensive patients and normotensive patients. The in-vitro function, in-vivo reendothelialization capacity and GTPCH/BH4 pathway of human EPCs were evaluated.

RESULTS

Both in-vitro function and reendothelialization capacity of EPCs were lower in hypertensive patients than that in normotensive patients. The GTPCH/BH4 pathway of EPCs was downregulated in hypertensive patients. Shear stress increased in-vitro function and reendothelialization capacity of EPCs from hypertensive patients and normotensive patients. Furthermore, shear stress upregulated the expression of GTPCH I and levels of BH4, nitric oxide, and cGMP of EPCs, and reduced thrombospondin-1 expression. With treatment of GTPCH knockdown or nitroarginine methyl ester inhibition, shear stress-induced increased levels of BH4, nitric oxide and cGMP of EPCs was suppressed. When GTPCH/BH4 pathway of EPCs was blocked, the effects of shear stress on in-vitro function and reendothelialization capacity of EPCs were inhibited.

CONCLUSION

The study demonstrates for the first time that shear stress-induced upregulation of the GTPCH/BH4 pathway ameliorates hypertension-related decline in endothelial repair capacity of EPCs. These findings provide novel nonpharmacologic therapeutic approach for hypertension-related endothelial repair.