ALPHA-LIPOIC ACID SUPPLEMENTATION PREVENTS SYMPTOMS OF VITAMIN-E-DEFICIENCY

alpha-Lipoic acid, an essential cofactor in mitochondrial dehydrogenas es, has recently been shown to be a potent antioxidant in vitro, as we ll as being capable of regenerating vitamin E in vitro. In this study, using a new animal model for rapid vitamin E deficiency in adult anim als and a new technique for tissue extraction of oxidized and reduced alpha-lipoic acid, we examined the antioxidant action of alpha-lipoic acid in vivo. Vitamin E-deficient adult hairless mice displayed obviou s symptoms of deficiency within five weeks, but if the diet was supple mented with alpha-lipoic acid the animals were completely protected. A t five weeks on a vitamin E-deficient diet animals exhibited similar d ecreases in tissue vitamin E levels, whether supplemented or unsupplem ented with alpha-lipoic acid: vitamin E levels in liver, kidney, heart , and skin decreased 70 to 85%; levels in brain decreased only 25%. Th ese data show that there was no effect of alpha-lipoic acid supplement ation on vitamin E tissue concentrations, arguing against a role for a lpha-lipoic acid in regenerating vitamin E in vivo. (C) 1994 Academic Press, Inc.