Neuropathological studies of chronic vitamin E deficiency in mammals including humans.

Lesions in the nervous system and skeletal muscles of vitamin E-deficient rats, monkeys and humans were studied morphologically and morphometrically. The experimental animals were fed purified, vitamin E-deficient diets for periods from two months to six years. In some studies deficient animals were repleted by feeding 200 mg all-rac-alpha-tocopheryl acetate/kg diet. The humans were children with congenital biliary atresia, low serum levels of vitamin E, and a consistent, progressive neurological syndrome. These studies demonstrate that chronic vitamin E deficiency in rats, monkeys and humans is characterized by a progressive, systematic degeneration of large calibre, myelinated sensory axons in spinal cord and peripheral nerves. The axonopathy is most severe in the rostral segments of the posterior or dorsal columns. Dystrophic axons are numerous in the sensory relay nuclei of cord and medulla in rats and humans, and infrequent in monkeys. Primary, necrotizing myopathy occurs regularly in vitamin E-deficient rats and monkeys. Regenerative changes in the peripheral nerves and skeletal muscles of deficient animals are morphologically typical and develop promptly, despite the deficiency. Repletion of deficient animals with vitamin E interrupts both the axonopathy and the myopathy, indicating the direct role of vitamin E deficiency in the pathogenesis of both lesions.