Demential syndromes and the lipid metabolism

Abstract

– The present communication surveys the present knowledge about the extent to which formation of free radicals in the central nervous system may give rise to cross-linking reactions finally ending in the deposition of lipofuscin pigments. Free radicals may be formed by autoperoxidation of polyunsaturated fatty acids. These fatty acids, e.g., C_22:6ω3, are enriched in rods and cones of the eye and in phosphatidyl ethanolamine of synaptosomes. By peroxidation, malondialdehyde is formed. This aldehyde may cross-link through amino groups of proteins and certain phospholipids. Hereby, lipofuscin is deposited. The peroxidation process is counteracted by certain enzymic systems and by antioxidants. Thus, glutathionperoxidase (GSH-Px), catalase and superoxid dismutase may eliminate peroxides. GSH-Px is a selenium-containing enzyme. Peroxides are also formed by metabolic transformation of dopamine. 3 demential syndromes, i.e. Alzheimer's, Parkinson's and Batten's diseases, are discussed with regard to whether the “free radical theory” may explain the pathogenesis. Finally, it is discussed whether an antioxidative treatment including vitamins E and C as well as a supplement of selenium, e.g. sodiumselenite, may be a therapeutic alternative to other types of treatment of demential syndromes or a direct supplement to the L-DOPA treatment of Parkinson's disease.