Relationship between serum lipids levels and lipid oxidizability in hypertensive patients

Hypertensive patients are highly susceptible to oxidizability. Although hypertension is common among Iranians, few data are available about lipid oxidation status in the involved people. The aim of this study was to evaluate the relationship between serum lipids levels and susceptibility of lipids to oxidation in hypertensive patients. Fasting serum lipids and uric acid (UA) were determined in 100 patients with established hypertension, aged 56 ± 12.6 years. In addition, cooper induced serum lipid oxidation was evaluated. Total cholesterol (TC) and triglycerides were determined by enzymatic method (cholesterol oxidase and glycerol oxidase respectively) and uric acid was measured by uricase method. Test kits were supplied by Zistshimi, and technicon-RA-1000 autoanalyser was used for analysis. Lipid oxidation was followed by the formation of conjugated dienes at 245 nm, in diluted serum, after adding Cu2+. Quantitative parameters including lag-time, maximal rate (V-max), and maximal amount of lipid peroxide products (O-D-max) were evaluated. Microsoft Excel was used for preparing kinetic curve of lipid oxidation, and SPSS software (V.11.5) to compare and determine the correlation coefficient between variables. A significant correlation between Lag-time and serum level of uric acid was found (r=0.34, p=0.009). Also V-max and OD-max were significantly correlated with cholesterol (r=0.46, p=0.001, r=0.52, p=0.001) and triglyceride (r=0.34, p=0.008, r=0.38, p= 0.003). Our results revealed that in hypertensive patients higher levels of uric acid might have a protective effect against lipid oxidation. Higher levels of serum lipids apparently do not affect lipid oxidizability, but they do influence on the production of higher amount of lipid oxidation products