Synergistic influence of polypeptide growth factors on cultured human muscle.

In two- to five-week tissue cultures of biopsied adult human skeletal muscle, combined addition to the culture medium of insulin, fibroblast growth factor, and epidermal growth factor synergistically increased creatine kinase activity 17-fold, increased acetylcholine receptors tenfold, and accelerated muscle differentiation. This study provides the first demonstration of the beneficial influence of these peptides on human muscle. It also establishes a new culture medium, resulting in the following: (1) much better long-term growth and differentiation of biopsied adult human muscle; and (2) by allowing elimination of embryo extract and reduction of serum, an important step toward developing a fully defined medium for culturing biopsied adult human normal and pathologic muscle tissue.