Effect of long-term hemodialysis on plasma lecithin: cholesterol acyltransferase activity and the amounts and compositions of HDL2 and HDL3 in hemodialysis-treated patients with chronic renal failure: a 9-year longitudinal study.

BACKGROUND: Atherosclerosis was correlated with hemodialysis duration (HD) in chronic renal failure (CRF) patients. Dyslipidemias were identified as atherogenic risk factors. MATERIAL/METHODS: To investigate variations in HDL2 and HDL3 composition and lecithin: cholesterol acyltransferase (LCAT) activity as functions of HD, 20 CRF patients were selected for maintenance hemodialysis during the 9 years from April 1, 1991 to March 31, 2000. Blood samples were drawn four times: 1991 (T0, study begin), 1994 (T1), 1997 (T2), and 2000 (T3). T0 results were taken as references. RESULTS: Triacylglycerol concentrations were 1.12-fold higher at T1 (P<0.01), 1.31-fold at T2, and 1.63-fold at T3 (P<0.001). Increases of 14% and 33% of total cholesterol were noted at T2 (P<0.05) and T3 (P<0.001). Hypertriglyceridemia correlated with HD (r=0.70, P<0.05). LCAT activity decreased by 27%, 39%, and 51% at times T1, T2, and T3, respectively, this activity being negligible in 30% of patients at T2 and 40% at T3. An inverse relationship was noted between LCAT activity and HD (r=-0.80, P<0.001). Increases in HDL2-unesterified cholesterol (UC) and HDL3-UC were obtained at T2 and T3 (P<0.05), and high HDL2-triacylglycerols (TG) and HDL3-TG were noted at T1, T2, and T3 (P<0.001). HDL3-phospholipids (PL) values were diminished by 9% at T1 (P<0.05), 17% at T2, and 19% at T3 (P<0.001). CONCLUSIONS: Long-term hemodialysis aggravates lipid anomalies following CRF. Alterations in HDL composition contribute to the reduced efficacy of reverse cholesterol transport and patients are submitted to a greater risk for atherosclerosis.

Changes in serum lipids and antioxidant status in west Algerian patients with essential hypertension treated with acebutolol compared to healthy subjects.

BACKGROUND: Hypertension is a major health problem in both developed and developing countries. It is hypothesized that high blood pressure is associated with loss of balance between peroxidation and antioxidant factors. MATERIAL/METHODS: 40 patients with essential hypertension were studied to ascertain the effects of a selective b1-blocker (acebutolol, 400 mg/day) on serum lipids, antioxidant status, antioxidant enzyme activity in red blood cells (RBC), and membrane fatty acids composition. Each subject was screened by physical examination, ECG, echocardiography, and laboratory tests. The period of observation was 24 weeks, and the data were tested by 2-way ANOVA followed by Bartlett's least significant difference test. RESULTS: At 12 weeks, serum triacylglycerol was more elevated (+26%). At 24 weeks, apolipoprotein A-1 levels remained more elevated (+41%) in hypertensive subjects compared to controls. In hypertensive patients, total antioxidant status and total plasma antioxidant capability were lower at 12 weeks than controls, and increased after 24 weeks of treatment. At 12 weeks, superoxide dismutase, catalase and glutathione reductase activities in erythrocytes remained lower in hypertensive subjects compared to controls (-32%, -40% and -24%, respectively). At 24 weeks, these values were increased compared to those obtained at 12 weeks (+26%, +36% and +37%, respectively). At 12 and 24-weeks, total n-3 and n-6 fatty acids were decreased by 26%, 18% and 29%, 25%, respectively. CONCLUSIONS: These findings demonstrate the beneficial influence of a beta1-blocker (acebutolol) at 24 weeks by its action on serum lipids, antioxidant status and RBC antioxidant enzyme activities.

Very high alpha-tocopherol diet diminishes oxidative stress and hypercoagulation in hypertensive rats but not in normotensive rats.

BACKGROUND: Oxidative stress is closely related to cardiovascular diseases, such as atherosclerosis. Increasing dietary antioxidants, such as alpha-tocopherol, may prevent these diseases. However, in some pathologies, such as hypertension, oxidative stress is enhanced, thus alpha-tocopherol requirements may be raised. MATERIAL/METHODS: In eleven-week-old spontaneously hypertensive rats and normotensive Wistar Kyoto rats, we investigated the effects of a four-week very high alpha-tocopherol dietary enrichment (1,200 mg/kg diet, VH) on blood pressure, resistance to free radical aggression, and VLDL+LDL resistance to lipid peroxidation. Platelet aggregation and plasma lipid profile were also investigated. RESULTS: With either diet, hypertensive rats were more protected against oxidative stress than normotensive rats. Their capacity to withstand free radical aggression was better, and their VLDL+LDL particles were less sensitive to lipid peroxidation. In either group, the VH diet did not modify blood pressure values when resistance to free radical aggression was increased, but not the resistance of VLDL+LDL to lipid peroxidation. With the control diet, platelet aggregation was faster and higher in hypertensive rats vs. normotensive rats. It was decreased with the VH diet in hypertensive rats but increased in normotensive rats, when compared to their respective controls. Whatever the diet, plasma triacylglycerol, phospholipid and cholesterol concentrations were lower in hypertensive than in normotensive rats. Only cholesterol concentrations were diminished with the VH diet in hypertensive rats, but not in normotensive rats. CONCLUSIONS: These results indicate that very high alpha-tocopherol dietary amounts decrease cardiovascular risk in hypertensive rats with high oxidative stress, but have less effect on normotensive rats.