THE PLASMA HDL-SUBFRACTION PROFILE IN HYPERTENSIVE PATIENTS WITH HIGH HDL-CHOLESTEROL LEVELS

Abstract

Objective: The evaluation of cardiovascular risk (CVR) in arterial hypertension includes the estimation of high density lipoprotein (HDL-C). Although HDL-C is considered as a favorite CVR factor, the exact role that HDL-C subfraction profile play in the pathogenesis of atherosclerosis, especially in higher than usual HDL-C levels (>60 mg/dl) is currently under investigation. The aim of this study was to evaluate the plasma HDL subfraction profile of high HDL-C levels in hypertensive patients compared to normotensive subjects. Design and method: We studied 74 hypertensive patients (60 + 13 years, 62 females) and 24 normotensives, apparently healthy subjects (49 + 14 years, 22 females) with HDL-C equal or above 55 mg/dl. Cholesterol, HDL-C, and TG were determined enzymatically while LDL-C was calculated using the Friedewald formula. Plasma HDL particles were separated and determined electrophorically using Lipoprint System HDL Subfractions Kit. Aortic stiffness (c-f PWV) and central BP (cBP) were evaluated by carotid-femoral pulse wave velocity (Complior apparatus). Results: We found that hypertensive patients had increased age, BMI, office systolic and diastolic BP, PWV compared to normotensives. Regarding HDL, 10 HDL fractions were separated: fractions 1-3 were denoted as Large-HDL (L-HDL), fractions 4-7 constituted the Intermediate-HDL (I-HDL), and fractions 8-10 were denoted as Small-HDL (S-HDL) subfraction. Although HDL-C levels were similar between groups (76 + 13 vs. 81 + 17 mg/dl, p = 0.10), the percent distribution (%) of L-HDL was lower in hypertensives compared to normotensives (29.8±4.7% vs. 36.6±6.3%, p<0.001), % I-HDL was similar while % S-HDL was increased (27.3±3.7% vs. 20.4±4.4%, p<0.001). We found a significant negative correlation between L-HDL and SBP (rho = -0.48, p = 0.01) as well as cBP (rho = -0.52, p = 0.008) in younger hypertensive females before menopause (n = 26, 49 + 5 years). Conclusions: L-HDL particles, the most antiatherogenic HDL-C subfraction, were reduced in hypertensive patients with high HDL-C levels compared to normotensive subjects, suggesting that these patients are probably less protected against CV disease compared to normotensive subjects with similar HDL-C and LDL-C levels. Therefore, plasma HDL-subfraction profile might replace the HDL-C evaluation as a better biomarker of CVR in hypertensive patients, especially females before menopause.