Effects of lipoic acid and ω-3 long-chain polyunsaturated fatty acids on the kidney in the ovariectomized rat model of menopause.

OBJECTIVES: The loss of antioxidant protection from estrogen during menopause may lead to oxidative stress in the kidneys. Thus, antioxidant supplementation may potentially decrease the menopause-derived oxidative stress. The aim of this study was to evaluate the effect of α-lipoic acid (LA) and ω-3 long-chain polyunsaturated fatty acids on the redox profile of the kidneys in the ovariectomized rat model of menopause. METHODS: We assessed oxidative damage markers and antioxidant defenses in the kidneys of ovariectomized rats supplemented with LA, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). Animals received 3 mo of dietary supplementation. RESULTS: Ovariectomy did not increase the levels of the damage markers carbonyl and malondialdehyde. EPA supplementation increased carbonyl and malondialdehyde levels. Ovariectomy increased fumarase activity but did not affect the levels of vitamin C, glutathione, and glutathione S-transferase activity. LA, DHA, and EPA supplementation decreased fumarase activity, but increased the levels of vitamin C, glutathione, and glutathione S-transferase activity. Vitamin E, superoxide dismutase, glutathione peroxidase, and peroxide consumption were not affected by ovariectomy or supplementation. CONCLUSIONS: The results suggest that ovariectomy did not affect the redox profile in the kidneys. LA, DHA, and EPA supplementation increased certain endogenous antioxidants; however, EPA may have a prooxidant effect on the kidneys.

The effect of n-3 long-chain polyunsaturated fatty acids and lipoic acid on the heart in the ovariectomized rat model of menopause.

Menopause occurs as consequence of ovarian senescence that leads to a drop of oestrogen hormone. The decreased oestrogen levels combined with the impairment of the redox system may contribute to the increased risk of postmenopausal cardiovascular disease. Supplementation with antioxidants may be an alternative to reduce cardiovascular risk. The study evaluated the effect of dietary supplementation with docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and α-lipoic acid (LA) for a period of 16 weeks on oxidative stress biomarkers in the hearts of ovariectomized 3-month-old rats. Ovariectomy did not increase the level of the damage markers malondialdehyde and carbonyl, and both were decreased by LA supplementation. Ovariectomy increased the levels of the endogenous antioxidants glutathione, vitamin C and H2O2 consumption, after restoration by DHA, EPA, and LA supplementation. Vitamin E, glutathione peroxidase, glutathione-S-transferase, and superoxide dismutase are not altered by ovariectomy. Lipid and protein damage are not increased after ovariectomy and a portion of the endogenous antioxidants concomitantly increased, suggesting that hearts may be protected by these antioxidants. DHA, EPA, and LA restored these endogenous antioxidants, showing that all evaluated supplements are effective in modulating the antioxidant redox system in the heart. LA showed additional effect on redox markers, decreasing lipid and protein damage markers.

Therapeutic Hypothermia Reduces Oxidative Damage and Alters Antioxidant Defenses after Cardiac Arrest.

After cardiac arrest, organ damage consequent to ischemia-reperfusion has been attributed to oxidative stress. Mild therapeutic hypothermia has been applied to reduce this damage, and it may reduce oxidative damage as well. This study aimed to compare oxidative damage and antioxidant defenses in patients treated with controlled normothermia versus mild therapeutic hypothermia during postcardiac arrest syndrome. The sample consisted of 31 patients under controlled normothermia (36°C) and 11 patients treated with 24 h mild therapeutic hypothermia (33°C), victims of in- or out-of-hospital cardiac arrest. Parameters were assessed at 6, 12, 36, and 72 h after cardiac arrest in the central venous blood samples. Hypothermic and normothermic patients had similar S100B levels, a biomarker of brain injury. Xanthine oxidase activity is similar between hypothermic and normothermic patients; however, it decreases posthypothermia treatment. Xanthine oxidase activity is positively correlated with lactate and S100B and inversely correlated with pH, calcium, and sodium levels. Hypothermia reduces malondialdehyde and protein carbonyl levels, markers of oxidative damage. Concomitantly, hypothermia increases the activity of erythrocyte antioxidant enzymes superoxide dismutase, glutathione peroxidase, and glutathione S-transferase while decreasing the activity of serum paraoxonase-1. These findings suggest that mild therapeutic hypothermia reduces oxidative damage and alters antioxidant defenses in postcardiac arrest patients.

Treatment of oxidative stress in brain of ovariectomized rats with omega-3 and lipoic acid.

SCOPE: Postmenopausal women are often affected by a group of metabolic disorders related to oxidative stress. Alternative treatments that can improve the quality of life of these women have been the subject of recent studies. The objective of this study was to evaluate the response to oxidative stress in the brains of rats following ovariectomy, and to determine enzymatic and nonenzymatic antioxidant responses when the animals received 3 months of dietary supplementation. METHODS AND RESULTS: Ovariectomy produced changes in antioxidant profiles characterized by reductions in glutathione S-transferase activity, H2 O2 consumption, superoxide dismutase activity, and vitamin C levels and increases in protein carbonylation. Docosahexaenoic fatty acid (DHA) supplementation restored these parameters to normal values and increased values of other antioxidants (glutathione peroxidase and total glutathione). However, DHA supplementation also increased protein carbonylation and lipid peroxidation. Eicosapentaenoic acid supplementation produced no changes in antioxidants, but decreased lipid peroxidation. Lipoic acid supplementation increased consumption of H2 O2 and decreased protein carbonylation and lipid peroxidation. CONCLUSION: These results suggest that the antioxidant response to omega-3 varies in different tissues, and in this study DHA treatment had a prooxidant effect in the brain. Lipoic acid treatment, on the other hand, had a protective effect, reducing markers of oxidative damage.