Antioxidant enzyme activities and malondialdehyde levels related to aging.

BACKGROUND: Free oxygen radicals have been proposed as important causative agents of aging. We have evaluated age-related changes in antioxidant enzyme activities and lipid peroxidation. METHODS: We measured erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and plasma malondialdehyde (MDA) levels. One hundred and seventy six healthy subjects were divided into five groups: Group 1 (n = 25; 0.2-1 year-old), Group 2 (n = 28; 2-11 years), Group 3 (n = 23: 12-24 years), Group 4 (n = 40; 25-40 years), Group 5 (n = 60: 41-69 years). RESULTS: SOD activities in Group 5 were significantly lower than in the other groups (P < 0.001). GPx and CAT activities and MDA levels in Group 5 were significantly higher than the other groups (P < 0.001, respectively). CAT activity in Group 4 was significantly higher than group 1 and group 2 (respectively, P < 0.001), and in group 3 was high compared to Group 2 (P < 0.001). There were negative correlations between SOD activities and age (P < 0.001). Conversely, there were positive correlations between CAT, GPx and MDA levels and age (P < 0.001). CAT activities of women in Group 2 were found to be high compared to the men (P < 0.05). MDA levels of women in Group 5 were higher than in the male groups (P < 0.001). CONCLUSIONS: We found age-related differences in erythrocyte antioxidant enzyme activities. Furthermore, peroxidative injury is raised in the aging process.

Antioxidant status and lipid peroxidation in hemodialysis patients undergoing erythropoietin and erythropoietin-vitamin E combined therapy.

In this study, plasma and red blood cell (RBC) antioxidant status and plasma lipid peroxidation were investigated in 46 hemodialysis patients. In addition, the effect of erythropoietin (EPO) and EPO-vitamin E combination therapy on plasma and RBC antioxidant status, and plasma lipid peroxidation were examined. There were 10 healthy subjects in the control group and 10 hemodialysis patients in the untreated group. The third group included 36 hemodialysis patients that were given EPO (100 U/kg) for 3 months, 3 times per week. The fourth group included 36 hemodialysis-patients from the EPO group that were given EPO at a 50% decreased dose + vitamin E (300 mg/day) for 3 months. MDA levels in the untreated group, the EPO group and the EPO + vitamin E groups were found to be higher than the control group (p < 0.001, in both). Furthermore, MDA levels in both of the treatment groups were lower when compared to the untreated group (p < 0.001, in both). Plasma vitamin E levels in the untreated, the EPO group and EPO + vitamin E groups were lower than the control group (p < 0. 001). In contrast, plasma vitamin E levels in the treatment groups were higher in comparison with the control group (p < 0.05). SOD activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001). SOD activities in the treatment groups were higher than the control group (p<0.001). The SOD activities in the EPO+vitamin E group increased when compared to the EPO group (p < 0.001). CAT activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001 in untreated and EPO groups, p <0.01 in EPO+ vitamin E group). CAT activities in EPO and EPO+ vitamin E groups were increased when compared to the untreated group (p < 0.01). In conclusion, our findings have shown that antioxidant status decreased and lipid peroxidation increased in hemodialysis patients. EPO has an antioxidant effect on the RBC and plasma antioxidant status, and plasma lipid peroxidation. These effects were moderately increased by the combination of vitamin E and EPO.

Effects of postmenopausal hormone replacement and alpha-tocopherol on the lipid profiles and antioxidant status.

Sixty-six postmenopausal women were randomly divided into three groups. The first group (n = 22) received transdermal oestradiol (0.05 g/day) for six months. Transdermal oestradiol was given during three weeks but was not given in the following week of each month during six months. In addition to the first group's therapy, medroxyprogesterone acetate (MPA; 10 mg/day, per orally) was administered to the second group (n = 22) for the last ten days. Vitamin E (600 mg/day, per orally) was given to the third group (n = 22) in addition to the first and second group therapy every day during six months. Total cholesterol, high density lipoprotein (HDL), very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels of the three groups were measured at the beginning and at the end of therapy. In the transdermal oestradiol and transdermal oestradiol + MPA groups, post-treatment serum total, VLDL and LDL cholesterol levels decreased (P < 0.05) whereas HDL cholesterol level increased (P < 0.05). No significant difference was found in the levels of MDA, SOD and GSH-Px. In the third group, pre-treatment levels of total (P < 0.05), VLDL (P < 0.05), LDL cholesterol (P < 0.01) and MDA (P < 0.05) were high compared to post-treatment. Inversely, HDL cholesterol (P < 0.05) and vitamin E (P < 0.01) levels increased after the treatment. However, there was no significant difference in the levels of SOD and GSH-Px. In conclusion, in the post-menopausal period, because of the positive changes after hormone replacement plus vitamin E therapy, we suggest that hormone replacement and vitamin E combined therapy is effective in prevention of cardiovascular diseases.