ABNORMALITY OF CULTURED MUSCLE AND SCHWANN-CELLS IN FAMILIAL LIPID NEURO-MYOPATHY - MUSCLE CORRECTED BY NEURAL INFLUENCE

Muscle and Schwann''s cell cultures were established from a family (mother and 2 sons) with non-carnitine deficient neuromyopathy. EM of noninnervated cultured muscle showed poorly matured muscle fibers containing large mushy mitochondria, lipid droplets, abundant multilaminated inclusions and dense-core dark osmiophilic bodies. Parallel innervated muscle fibers (cocultured with normal-rat motor neurons for 2-3 wk) were well cross-striated, had well-developed T tubules and sarcoplasmic reticulum and none of the abnormalities of aneural muscle cultures. Cultured Schwann''s cells were normal by light microscopy, but had ultrastructurally abnormal mitochondria, lipid droplets, dark osmiophilic granular inclusions, and numerous foamy vacuoles. These studies demonstrated the following: intrinsic muscle and Schwann''s cell defects because of reproduction of abnormalities in culture; normal muscle cell responsiveness to innervation reflected by development of contractions and longer survival in culture; beneficial influence of a neural factor(s) on the endogenous muscle cell abnormality.