Expression of muscle-specific isozymes of phosphorylase and creatine kinase in human muscle fibers cultured aneurally in serum-free, hormonally/chemically enriched medium.

Primary cultures of muscle cells derived from a biopsied adult human skeletal muscle were grown up to 6 weeks in a hormonally/chemically enriched serum-free medium. The expression of muscle-specific isozymes of creatine kinase, glycogen phosphorylase, and phosphoglycerate mutase, indicative of muscle cell maturation, was studied after 1, 4 and 6 weeks of growth. The maturation of muscle fibers cultured in serum-free medium was comparable to that achieved by muscle fibers cultured in medium containing 10% serum and supplemented with growth factors (insulin, epidermal growth factor, and fibroblastic growth factor) and was greater than that achieved in medium containing 10% serum only. Our study demonstrates that adult human muscle can be cultured aneurally for a long period of time in a serum-free medium, and that it can achieve a high degree of maturation. This study provides an important basis for investigations related to: (1) assessment of the influence of individual components of the medium on human muscle maturation in culture; (2) studies of regulation of abnormal gene expression in diseased human muscle cultured in serum-fre medium.