Association of serum antioxidants and risk of coronary heart disease in South Indian population.

BACKGROUND AND AIM: Higher prevalence of coronary heart disease (CHD) has been reported in south Indian population, which cannot be accounted for by the traditional risk factors like hyperlipidemia. Identification of new risk factors may help in treatment and prevention of CHD in this part of the world. In an attempt to investigate the causes of increased incidence of CHD in this part of the world, we intended to look for oxidative stress in our patients as a possible risk factor. As an initial step in this perspective, a case- control study was conducted to find out the serum antioxidant levels and their association with CHD in south Indian population. SETTINGS AND DESIGN: A tertiary care hospital; Case--control study. MATERIALS AND METHODS: One hundred thirty nine angiographically proven CHD patients (aged 29-75 years) were studied against 59 population based healthy controls (aged 29-72 years) free of CHD. Fasting serum cholesterol, triglycerides, HDL cholesterol, erythrocyte and plasma glutathione peroxidase and superoxide dismutase were estimated on automated clinical chemistry analyzer. LDL cholesterol and VLDL cholesterol were calculated. Vitamins A and E were estimated using high performance liquid chromatography (HPLC). STATISTICAL ANALYSIS: Unpaired t test was used to compare means. Binary logistic regression was done to find out the association between dependent and independent variables. RESULTS: Significantly higher levels of Total Cholesterol/HDL cholesterol and LDL cholesterol/HDL cholesterol ratio and lower HDL cholesterol levels were observed in patients when compared to controls. No significant difference of plasma and erythrocyte glutathione peroxidase and superoxide dismutase activity was observed between patients and controls. Significantly lower levels of vitamin E in patients than in controls was observed (P<0.001). Serum vitamin E was inversely associated with coronary heart disease even after controlling for age and other coronary risk factors (Odds ratio 0.898, 95% CI 0.826-0.976 P=0.01). CONCLUSIONS: The results of present study suggest that deficiency of vitamin E may be an independent risk factor of CHD. This study brings out the need for long- term monitoring of vitamin E supplementation as a preventive measure for CHD in the population studied.

Lipoprotein (A): Better assessor of coronary heart disease risk in south Indian population.

In an attempt to search for risk factors which can explain the increasing prevalence of coronary heart disease (CHD) in Indian population, we conducted a case-control study to assess the association of Lipoprotein (a)(Lp(a)) with CHD. One hundred and fifty one consecutive patients with clinical and angiographic evidence of CHD and forty-nine healthy controls were drawn for the study. Triglycerides, very low density cholesterol (VLDL-C), total cholesterol (total-C)/high density cholesterol (HDL-C) ratio, low density cholesterol (LDL-C)/HDL cholesterol ratio and Lp(a) were found to be higher in patients than controls. In female sex and in those with family history of CHD, higher total and LDL cholesterol levels were observed to be associated with higher Lp(a) levels. Lp(a) levels were also found to be higher in triple vessel disease than other vessel disease patients. Significant difference in Lp(a) levels were observed between normal coronaries vs. single and triple vessel disease(P<0.05) and also between single vs. double and triple vessel disease (P<0.01).Lp(a) levels correlated positively with vessel severity(P<0.005). Lp(a) levels >25 mg/dl were associated with coronary heart disease (Odds ratio 1.98 P<0.05 95% CI 0.007-1.18). Our findings suggest a cut-off level of 25mg/dl for determination of risk of CHD. Studies from different areas involving larger sample size are needed to confirm the findings of the present study.

Oxidative stress in hemodialysis--postdialytic changes.

BACKGROUND: There is evidence for production of free oxygen radicals during hemodialysis. Hemodialysis is an intervention that is intermittent and is usually undertaken once in two or three days. It is known that the free oxygen radicals are short lived. Hence, it is necessary to know how long the effects of this oxidative stress are seen in the postdialytic period and whether they are carried over to the next dialysis. Review of the literature showed that there is no information in this area. Hence, this study was undertaken in order to learn whether oxidative stress due to a dialysis session is carried over to next dialysis session or not. METHODS: The effects were studied after four different types of membrane and dialysate--Polysulphone-Bicarbonate (PB), Polysulphone-Acetate (PA), Cuprophan-Acetate (CA) and Cuprophan-Bicarbonate (CB). Two consecutive dialysis sessions were studied to know the effect of re-use of the membrane. For each dialysis session, blood samples were collected at 0 (immediately prior to dialysis or preHD), 4 (immediate postdialysis), 6, 12, 24 and 48 hours (start of next session). Lipid peroxides, SOD and GP were determined in erythrocytes. Vitamins A and E and lipid peroxides were estimated in plasma. RESULTS: In the postdialytic phase there was an increase in plasma lipid peroxide levels. Plasma vitamin E levels increased significantly in all groups after first use dialysis, whereas the increase found after re-use dialysis was not statistically significant. Erythrocyte lipid peroxide levels showed a significant decrease. No significant changes were observed in the plasma vitamin A, erythrocyte SOD and GP levels. There was no significant change in any of the parameters between preHD and either 48-hour or 96-hour samples in all groups studied. CONCLUSIONS: Our results show that there is no carry-over of oxidative stress produced by dialysis to the next session regardless of the type of dialysis.