HDL cholesterol levels and endothelial glycocalyx integrity in treated hypertensive patients

: 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.