Muscular dystrophy, nutritional

Vitamin E deficiency results in the development of necrotizing myopathy, sometimes including cardiac muscle. This has been called nutritional muscular dystrophy, an unfortunate term, because deficiency of the vitamin is not a factor in the etiology of human muscular dystrophies, and supplements of the vitamin have no beneficial effect. The myopathy responds to selenium, but not to synthetic antioxidants. 

It is convenient to mention here that Fitzpatrick and Pennington (F6) studied the metabolism of acetoacetate- C by dystrophic mouse muscle in vitro. They found no significant difference between normal and dystrophic muscle in the production of C02, but the incorporation of C into nonvolatile compounds was much higher in the dystrophic muscle. In nutritional muscular dystrophy in the chicken, Jenkins (J3) found that acetoacetate oxidation by muscle homogenates was unaltered, but the utilization of /8-hydroxybutyrate was impaired. 

K14. Krupnick, A. B., Casa, C. M., and Rosenkrantz, H., Nucleic acid content in nutritional muscular dystrophy. Arch. Biochem. Biophys. 106, 89-94 (1964). 

Characteristic lesions of vitamin E deficiency in animals include necrotizing myopathy (inaccurately referred to as nutritional muscular dystrophy), exudative diathesis, nutritional encephalomalacia, irreversible degeneration of testicular tissue, fetal death and resorption, hepatic necrosis, and anemia. Several of these conditions are directly related to peroxidation of unsaturated lipids in the absence of vitamin E, and others can be prevented by synthetic antioxidants or vitamin E. 

Certain aspects of the pathology of vitamin E deficiency suggest that nucleic acid metabolism may be deranged. In tissues severely affected by the deficiency one sees various nuclear changes. These include an increase in numbers of nuclei in rabbit skeletal muscle, appearance of giant multi-nucleated cells in rat testes (Mason, 1933), and the appearance of many multinucleated erythroid precursors in vitamin E-deficient monkey bone marrow (Porter et al., 1962). It is of course well known that these tissues are dramatically affected by vitamin E deficiency in the various species. In the rabbit one sees nutritional muscular dystrophy, in the male rat sterility, and in the monkey macrocytic anemia (Dinning and Day, 1957a). 

B. Exudative Diathesis and Nutritional Muscular Dystrophy in Chicks... 

C. Interrelationship of Vitamin E, Selenium, and Sulfur Amino Acids IN Prevention of Nutritional Muscular Dystrophy in Chicks... 

Nutritional muscular dystrophy in the chick, pictured in Fig. 3 p. 627, is characterized by degeneration of the muscle fibers, especially of the breast (pectoral) mus< les, but also occurring occasionally in the leg muscles. 

However, in more recent studies, Scott and Calvert (1960, 1962) found that cystine is more effective than methionine and, therefore, that cystine may be more closely related to the primary metabolic function responsible for prevention of nutritional muscular dystrophy. Representative results of these experiments are shown in Table II. Although 0.19% DL-methionine... 

Although selenium in the diet of pregnant ewes has been shown by Muth and associates (1958) and Proctor et al. (1958) to be of primary importance for prevention of nutritional muscular dystrophy in newborn lambs, studies by Dam and Sdndergaard (1957) and Nesheim and Scott... 

These results demonstrate therefore that hath selenium and vitamin E are concerned in prevention of both exudative diathesis and nutritional muscular dystrophy and that cystine also plays an important role in the prevention of muscular dystrophy. 

Vitamin E has been shown over the past forty years to be important in the nutrition of poultry in health and disease, not only for normal reproduction but also (1) as nature s most effective antioxidant for prevention of encephalomalacia, (2) in a specific role, interrelated with the action of selenium, for prevention of exudative diathesis, and (3) in another role, interrelated with both selenium and cystine, for prevention of nutritional muscular dystrophy. 

Both skeletal and cardiac muscle are affected in deficient animals. This is sometimes called nutritional muscular dystrophy. This is an unfortunate term as there is no evidence that human muscular dystrophy is related to vitamin E deficiency, and it is better called necrotizing myopathy. 

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