Shear Stress Induced by Acute Heat Exposure Is Not Obligatory to Protect Against Endothelial Ischemia-reperfusion Injury in Humans

Acute heat exposure protects against endothelial ischemia-reperfusion (I/R) injury in humans. However, the mechanism/s mediating this protective effect remain unclear. We tested the hypothesis that inhibiting the increase in shear stress induced by acute heat exposure would attenuate the protection of endothelial function following I/R injury. Nine (3 women) young healthy participants were studied under 3 experimental conditions: 1) thermoneutral control; 2) whole-body heat exposure to increase body core temperature by 1.2 °C; 3) heat exposure + brachial artery compression to inhibit the temperature-dependent increase in shear stress. Endothelial function was assessed via brachial artery flow-mediated dilatation before (pre-I/R) and after (post-I/R) 20 min of arm ischemia followed by 20 min of reperfusion. Brachial artery shear rate was increased during heat exposure (681 ± 359 s-1), but not for thermoneutral control (140 ± 63 s-1; P < 0.01 vs. heat exposure) nor heat + brachial artery compression (139 ± 60 s-1; P < 0.01 vs. heat exposure). Ischemia-reperfusion injury reduced flow-mediated dilatation following thermoneutral control (pre-I/R, 5.5 ± 2.9 % vs. post-I/R, 3.8 ± 2.9 %; P = 0.06), but was protected following heat exposure (pre-I/R, 5.8 ± 2.9 % vs. post-I/R, 6.1 ± 2.9 %; P = 0.5) and heat + arterial compression (pre-I/R, 4.4 ± 2.8 % vs. post-I/R, 5.8 ± 2.8 %; P = 0.1). Contrary to our hypothesis, our findings demonstrate that shear stress induced by acute heat exposure is not obligatory to protect against endothelial I/R injury in humans.

Male sex hormone as a correlate of endothelial function in middle-aged Indian males: a cross-sectional prospective observational study

Background: Data on relationship between serum testosterone and endothelial dysfunction measured by brachial artery flow-mediated dilatation (BAFMD) in Indian subset are scarce. The present study was envisaged to assess the correlation between serum testosterone and endothelial dysfunction measured by BAFMD.Methods: From October 2013 till September 2014, 92 Indian male patients aged 40-60 years who underwent investigation of flow-mediated dilatation of the brachial artery using ultra sonography were included. The association between serum testosterone and BAFMD percent-measured endothelial dysfunction was examined.Results: Multivariate regression analysis in 92 Indian male patients (mean age 53.12±6.3 years) revealed that low levels of total serum, serum free and serum bioavailable testosterone were significantly associated with BAFMD% and were independent of age, hypertension, diabetes, body mass index (BMI), current smoking and hyperlipidaemia (p<0.001). The total serum, serum free and serum bioavailable testosterone were positively correlated with BAFMD% with Pearson correlation coefficients of r=0.572, r=0.525 and r=0.547, respectively (p<0.001).Conclusions: Low levels of total serum, serum free and serum bioavailable testosterone were significantly associated with BAFMD%-measured endothelial dysfunction, irrespective of cardiovascular risk factors.

Cytomegalovirus may influence vascular endothelial health in Indonesian HIV-infected patients after 5 years on ART

Objectives Accelerated atherosclerosis in older HIV-infected patients has been attributed to persistent immune activation and high burden cytomegalovirus (CMV), as demonstrated in transplant recipients and the general population. Here we assess CMV and inflammatory markers linked with vascular health in young adult patients treated in Indonesia. Study design HIV-infected adults (n = 32) were examined when they began antiretroviral therapy (ART) with < 200 CD4 T-cells/µl (V0) and after 60 months (V60). Age-matched healthy controls (HC, n = 32) were assessed once. Methods Flow Mediated Dilatation (FMD) was assessed by ultrasound on brachial arteries at V60 and in HC. Plasma markers of immune activation and endothelial activation, and CMV antibodies (lysate, gB, IE-1) were assessed in all samples. Results were assessed using bivariate (non-parametric) and multivariable analyses. Results Levels of inflammatory biomarkers and CMV antibodies declined on ART, but the antibodies remained higher than in HC. FMD values were similar in patients and HC at V60. In HIV patients, levels of CMV lysate antibody correlated inversely (r = − 0.37) with FMD. The optimal model predicting lower FMD values (adjusted R2 = 0.214, p = 0.012) included CMV lysate antibodies and chondroitin sulphate. In HC, levels of sTNFR correlated inversely with FMD (r = − 0.41) and remained as a risk factor in the optimal multivariable model, with CMV glycoprotein-B (gB) antibody predicting a healthier FMD (adjusted R2 = 0.248, p = 0.013). Conclusions Higher levels CMV antibodies optimally predict vascular health measured by FMD in HIV patients. However in healthy controls, sTNFR marks risk and CMV gB antibody may be protective.

FLOW MEDIATED DILATATION, CAROTID INTIMA MEDIA THICKNESS, ANKLE BRACHIAL PRESSURE INDEX AND PULSE PRESSURE IN YOUNG MALE POST MYOCARDIAL INFARCTION PATIENTS

Introduction:Due to increase in Coronary Artery Disease (CAD) at a younger age, we should try to diagnose atherosclerotic process and population at risk, at the earliest. Flow Mediated Dilatation (FMD), Carotid Intima-Media Thickness (CIMT) and Ankle-Brachial Pressure Index (ABI) are probable markers for early atherosclerosis and may be useful in coronary risk stratification Objectives: To compare and correlate the FMD, CIMT, ABI and Pulse Pressure (PP) in young male patients of Myocardial Infarction (MI) with age and sex matched healthy controls Method50 patients of MI aged ≤45 years, who presented to iccu of Department of Medicine Indira Gandhi medical college Nagpur India, were recruited consecutively for this case control study and same number of age and sex matched healthy controls were also analyzed. 3 days after Myocardial infarction FMD of the brachial artery, intima media thickness of carotid artery, ABPI and PP were measured in the cases and compared with healthy control Results: The FMD was lower among young patients of MI than controls . CIMT was higher among cases than controls . ABI was lower among cases than controls . Compared to controls, PP was higher among cases . In all subjects, a negative correlation between FMD and CIMT and a positive correlation between FMD and ABPI was found. A statistically significant negative correlation was found between endothelial dependent FMD and PP among cases and control groups Conclusion: Biophysical parameters were deranged in young post MI patients. Majority of our young male patients fell in low risk Framingham risk score but still they manifested with CAD. Despite 3 days of treatment among young male patients of MI, various biophysical parameters were stillderanged.

Depression and Endothelial Dysfunction in Psoriatic Arthritis: Is There Any Possible Relationship?

Background: Cardiovascular events (CVEs) are the first cause of death in patients with psoriatic arthritis (PsA). Depression is a recognized risk factor in cardiovascular events and is frequently associated with PsA. Flow-mediated dilatation (FMD) is a widely used method for assessing endothelial dysfunction, a parameter with strong prognostic implications for CVEs. The study aims to explore the relationship between FMD, depressive symptoms and serum cytokines in a cohort of patients with PsA.Patients and Methods: FMD was assessed in 50 consecutive PsA patients aged between 30 and 75 years without known cerebrovascular and coronary heart disease or diabetes. Depressive symptoms were reported using the related subscale of the Hospital Anxiety and Depression Scale (HDS). Disease features, activity indexes, and adjusted Framingham risk score (aFRS) were calculated. Serum level of IL-6, TNF-α, and IL-17A were also assessed.Results: In PsA patients (age 50.7 ± 10.2 years, male 42%, disease duration 5.9 ± 3.3 years, Disease Activity in PSoriatic Arthritis (DAPSA) score 14.0 ± 9.4) FMD inversely correlated with the severity of depressive symptoms according to HDS (ρ = −0.339, p = 0.016), age (ρ = −0.507, p = 0.001), aFRS (rs = −0.453, p &lt; 0.001), duration of PsA (ρ = −0.507, p = 0.001), intensity of pain (ρ = −0.507, p = 0.001), and DAPSA (ρ = −0.507, p = 0.001). No statistically significant correlation was found between FMD or HDS and serum cytokines concentrations. HDS predicted FMD in a model adjusted for age, aFRS, PsA duration, and pain intensity (β = −0.271, p = 0.008), with depressive symptoms contributing directly to 6.4% of the variance.Conclusions: Depressive symptoms correlate with endothelial dysfunction with an exposure-response pattern in our cohort of PsA patients.

Study on prediction of arterio-venous fistula maturation by flow mediated dilatation and AVF blood flow

Background: The physiology and pathology of AVF maturation depends on the vessels characteristics and its ability to remodel. Outcome of AVF using flow mediated dilatation (FMD), AVF blood flow and diameter has been studied. Methodology: Present observational study included single stage AVF (both Radiocephalic and Brachiocephalic) in consecutive CKD five patients ( n = 158) prospectively over 1 year. Demographic and Doppler ultrasound parameters of upper limb (for vessel diameter and FMD) at baseline were recorded. Blood flow, diameter and depth of AVF were studied at 2, 6 and 12 weeks and their association with clinical maturation (usage of fistula with two needles for 75% of dialysis sessions during 15 day period) was studied ( n = 129, after excluding lost to followup and expired patients; accordingly cohort was divided in matured ( M) or non-matured (NM) groups. Clinical and radiological parameters between both groups were compared; receiver operator curve (ROC) and correlation of Doppler parameters were analysed. Results: Of 129 AVF, 67.4% were matured and 32.5% non-matured. Mean age was 40 years with male predominance75% in both the groups. The mean arterial diameter for distal (NM = 1.96 ± 0.58 and M = 2.02 ± 0.41) and proximal AVF (NM = 3.37 ± 0.82 and M = 3.36 ± 0.75) was not statistically different in both the groups. The matured fistula group had a mean FMD of 11.67 ± 4.09 as against FMD value of 9.365 ± 3.55 in the failed fistula group ( p value 0.01). For maturation prediction, sensitivity and specificity of blood flow at 2 weeks were 86.2% and 59.5% and at 6 weeks 96.6% and 64.3%, respectively. In multivariate analysis predictors for AVF maturation were FMD (adjusted odds ratio (AOR) = 1.15) and blood flow (AOR = 1.67). Conclusion: Second and Sixth week AVF blood flow was found to be predicting AVF maturation. Higher baseline FMD correlated with the AVF maturation, but not with vessel diameter.

The Evaluation of Flow Mediated Dilatation and Blood Parameters in Raynaud Phenomenon

Introduction: Raynaud phenomenon (RP) is a multifactorial disorder. If any underlying disease cannot be detected responsible for RP then it considered as primary RP (pRP). We aimed to investigate the differences between laboratory markers and impaired endothelial function in pRP. Material and Methods: Forty-two pRP patients included as study and control groups were created from 30 healthy individuals. The endothelial function was evaluated with flow-mediated dilatation (FMD) of the brachial artery. The blood samples were obtained both groups and white blood cell [WBC], hemoglobin, platelet, mean platelet volume [MPV], creatinine, alanine aminotransferase [ALT], aspartate aminotransferase[AST], D-dimer, fibrinogen, albumin, fibrinogen to albumin ratio [FAR], Neutrophil to Lymphocyte ratio [NLR], D-dimer to albumin ratio [DDAR] and monocyte chemo-attractant protein-1 [MCP-1]. Obtained blood parameters and FMD values were compared between groups. Results: The groups were found as similar in regards to age, gender, smoking history (p<0.05). There was no difference between the two groups in regards to hemoglobin, platelet, MPV, creatinine, ALT, D-dimer, albumin, FAR, NLR, DDAR levels (p<0.05). AST levels were slightly higher in pRP group (p=0.027). Markedly increased WBC, fibrinogen, MPV and MCP-1 values were detected in pRP group (p=0.000). Additionally, higher abnormal FMD responses were detected in pRP group (p=0.000). There was a direct correlation between abnormal FMD response and serum MCP-1 values in patients with pRP (R: 0.308, R2: 0.095, p: 0.044). Conclusion: It seems to be that MCP-1 levels are higher in patients with pRP and increased values of MCP-1 levels seem to be related to impaired endothelial functions

The Effect of Magnesium Supplementation on Endothelial Function: A Randomised Cross-Over Pilot Study

Evidence supports an association between low magnesium (Mg) intake and coronary heart disease and between Mg intake and endothelial function. The aim of this study was to assess the effect of one week of Mg supplementation on endothelial function, assessed by flow mediated dilatation (FMD). Nineteen healthy men and women completed this cross-over pilot study in which participants were randomised to take an over-the-counter magnesium supplement for one week or to follow their usual diet. Weight, FMD and blood pressure (BP) were taken on completion of each intervention and 24 h urine collections and blood samples were taken to assess compliance. Baseline serum Mg was within normal range for all participants. Urinary Mg and urinary magnesium-creatinine ratio (Mg/Cr) significantly increased between interventions, (p = 0.03, p = 0.005, respectively). No significant differences in FMD or BP were found between the interventions. A significant negative correlation was seen between age and FMD (r = −0.496, p = 0.031). When adjusted for age, saturated fat was negatively associated with FMD (p = 0.045). One week of Mg supplementation did not improve FMD in a healthy population.