Plasma lipid peroxidation and totalantioxidant status among dyslipidaemic and hypertensive Nigerians with high risk of coronary heart disease.

Background: The oxidative modification hypothesis of atherosclerosis predicts that low density lipoprotein-cholesterol (LDL-C) oxidation is an early event in atherosclerosis and that oxidized LDL-C contributes to atherogenesis

Objective: To determine a link, if any, between the plasma lipid peroxidation and total antioxidant status (TAS) among dyslipidemic and hypertensive Nigerian patients with high risk of coronary heart disease.

Methods: The study groups comprised 58 hypertensive adult Nigerians whose fasting plasma total cholesterol (TC) levels were > 5.5 mmol/L and with high risk coronary heart disease (CHD) lipid fraction i.e. 'the ratio of high density lipoprotein cholesterol to total cholesterol' (HDL-C/TC) < 0.13 were selected for the study. The control groups comprised 58 non hypertensive adult Nigerians with (HDL-C/TC) > 0.30.

Results: The mean +/- SD TAS level (1.02 +/- 0.15 mmol/L trolox) for males and (0.99 +/- 0.17 mmol/L) for females were significantly reduced (p < 0.05) compared to the controls; however (MDA) level (5.15 +/- 0.82 mmol/ml) for males and (5.06 +/- 0.73 mmol/ml) for females were significantly increased (p < 0.01) compared to the controls. The mean +/- SD plasma TC and LDL-C malonyl level (5.87 +/- 0.23 mmol/L and 4.65 +/- 0.34 mmol/L) were significantly increased (p < 0.01) in males hypertensive compared to the control. An inverse correlation between the TAS/TC(r = -0.53, p < 0.001) and TAS/LDL-C (r = -0.50, p < 0.001), however a direct correlation between the MDA/TC(r = 0.51, p < 0.001) and MDA/LDL-C (r = 0.48, p < 0.01) for males hypertensive were found. In female subjects the mean +/- SD plasma TC (5.95 +/- 0.13 mmol/L) and LDL-C (4.45 +/- 1.04 mmol/L) were significantly increased (p < 0.05) and (p < 0.01) respectively compared to the controls. Also in hypertensive females inverse correlation between the TAS/TC (r = -0.59, p < 0.001) and TAS/LDL-C (r = -.41, p < 0.01), and a direct correlation between the MDA/TC ( r= .48, p < 0.01) and MDA/LDL-C (r = 0.31, p < 0.05) were found.

Conclusion: Since dyslipidaemia, hypertension and lipid peroxidation were directly relate to the severity of atherosclerosis, elimination of free radicals in the plasma before the peripheral tissues can take them up might reduce atherosclerosis. In view of our present findings, a management strategy aimed at simultaneously reducing lipid peroxidation and increasing total antioxidant status in dyslipidemic patients may be of benefit.