HDL cholesterol levels and endothelial glycocalyx integrity in treated hypertensive patients

Abstract

Endothelial dysfunction indicates target organ damage in hypertensive patients. The integrity of endothelial glycocalyx (EG) plays a vital role in vascular permeability, inflammation and elasticity, and finally to cardiovascular disease. The authors aimed to investigate the role of increased HDL cholesterol (HDL‐C) levels, which usually are considered protective against cardiovascular disease, in EG integrity in older hypertensive patients. The authors studied 120 treated hypertensive patients older than 50 years were divided regarding HDL‐C tertiles in group HDLH (HDL‐C ≥ 71 mg/dL, upper HDL‐C tertile) and group HDLL (HDL‐C < 71 mg/dL, two lower HDL‐C tertiles). Increased perfusion boundary region (PBR) of the sublingual arterial microvessels (ranging from 5 to 9 µm) using Sideview Darkfield imaging (Microscan, Glycocheck) was measured as a non‐invasive accurate index of reduced EG thickness. PBR 5‐9 was significantly decreased in group HDLH (P = 0.04). In the whole population, HDL‐C was inversely but moderately related to PBR 5‐9 (r = −0.22, P = 0.01). In a multiple linear regression analysis model, using age, BMI, smoking habit, HDL‐C, LDL‐C, and office SBP, as independent variables, the authors found that BMI (β = 0.25, P = 0.006) independently predicted PBR 5‐9 in the whole population. In older hypertensive patients, HDL‐C ranging between 71 and 101 mg/dL might moderately protect EG and subsequently endothelial function. Future studies in several groups of low‐ or high‐risk hypertensives are needed in order to evaluate the beneficial role of extremely elevated HDL‐C regarding cardiovascular risk evaluation as well as endothelial glycocalyx as a novel index of target organ damage in essential hypertension.

Sex‐related associations of high‐density lipoprotein cholesterol with aortic stiffness and endothelial glycocalyx integrity in treated hypertensive patients

“…Cigarette smoking is a major risk factor for CVD, exerting its effects by increasing arterial stiffness, leading to endothelial dysfunction, and accentuating oxidative stress 27,28 . In a previous study, we just found a trend toward an inverse relationship between HDL‐C and PBR 5‐9 in a small group of smoker hypertensives under treatment 8 . In the present study, an inverse association of HDL‐C and PBR 5‐9 was revealed in male hypertensive patients while we have not been able to prove any linear dependence of the following factors of age, weight, LDL‐C levels, and smoking habit to PBR 5‐9.…”

“…However, we did not prove any relationship between HDL‐C and EG in females which in turn enhances our conclusions regarding the significant role of increased HDL‐C in hypertensive males regarding EG function and the subsequent CV risk reduction. Nonetheless, the moderate relationship between HDL‐C and EG in males probably reflects the existence of other factors that affect EG function or even the presence of dysfunctional HDL particles in extremely elevated HDL‐C 8 (Figure 1) .…”

“…EG function is assessed through measurement of perfused boundary region (PBR) of the sublingual microvessels ranged 5‐25 μm 7 . In a previous study, we proved that HDL‐C ranged between 71 and 101 mg/dL might moderately protect EG and subsequently endothelial function in hypertensive patients, older than 50 years 8 . In this study, we aimed to investigate the role of increased HDL‐C levels, which usually are considered protective against CVD, in aortic stiffness and endothelial integrity in middle‐aged treated hypertensive patients regarding smoking habit.…”

“…The protocol of the study has been described with details in a previous study 8 . However, a short description follows :…”

“…We measured the PBR of the sublingual arterial microvessels (diameter ranged 5‐25 μm) using Sidestream Darkfield imaging (Microscan, Glycocheck, Microvascular Health Solutions Inc.) which is proposed as a valid method to assess endothelial integrity by the European Society of Cardiology Working Group on Peripheral Circulation 8,10‐12 …”