Abstract 14205: Malondialdehyde-Modified Low-Density Lipoprotein to High-Density Lipoprotein Cholesterol Ratio Predicts Endothelial Dysfunction
Purpose: Endothelial dysfunction is a predictor of cardiovascular event as well as an initial step of atherosclerosis. Oxidative stress plays a major role in the process of endothelial damage and atherosclerosis, whereas high-density lipoprotein cholesterol (HDL-C) exerts vascular protective effect. We investigated a clinical value of the malondialdehyde-modified low-density lipoprotein (MDA-LDL), an oxidized-LDL, to HDL-C ratio for evaluating endothelial function.
Methods: Middle-aged male subjects (n=70, 42±6 years) with hypertension (39%), dyslipidemia (56%), or smoking (53%) were enrolled, but those with obvious organ damage or those under any medication were excluded. Their blood pressure, LDL-C, HDL-C, non-HDL-C, and MDA-LDL levels were 133±14/84±11 mmHg, 118±35, 56±13, 147±36 mg/dl, and 120±43 U/L, respectively. Blood was sampled for the measurement of lipid profile, hs-CRP and CD34+ circulating endothelial progenitor cells (CPC, by flow cytometry). Simultaneously, endothelial function was assessed by flow-mediated dilation (FMD) using an ultrasound system.
Results: FMD (3.81±1.73%) was positively correlated with the CPC number (271±164 x106 cells/μl, r=0.236, p<0.05), and inversely correlated with age (r=−0.319, p<0.01), conventional lipid indices (non-HDL-C, total-C/HDL-C, LDL-C/HDL-C, and MDA-LDL), and MDA-LDL/HDL-C (2.26±1.0, r=−0.341, p<0.01). Multivariate regression analysis including possible parameters identified that MDA-LDL/HDL-C was a powerful independent predictor of FMD. Furthermore, only MDA-LDL/HDL-C was adopted as a significant determinant of FMD by step-wise regression analysis including age, smoking, blood pressure, lipid indices, and the CPC number as independent variables. Subjects in the highest tertile (upper 2.5) of MDA-LDL/HDL-C indicated significantly reduced FMD compared with those in other 2 tertiles (p<0.01).
Conclusions: Among various indices, MDA-LDL/HDL-C is a novel and independent index predicting endothelial dysfunction. The ratio that reflects the balance between oxidative stress and HDL-C is important in the initiation and/or progression of atherosclerosis. The MDA-LDL to HDL-C ratio is a possible candidate for powerful predictor of cardiovascular disease.
- © 2010 by American Heart Association, Inc.