Aminoterminal extension peptides from type I procollagen normalize excessive collagen synthesis of scleroderma fibroblasts.

Fibroblasts derived from a skin biopsy of a patient with scleroderma in the sclerotic stage were shown to have a higher rate of DNA synthesis, and to synthesize more collagen than fibroblasts from a healthy control. The addition of procollagen peptides to the culture medium of scleroderma fibroblasts almost normalized the collagen synthesis. This observation indicates that the mechanism for the regulation of collagen synthesis by feed back inhibition of prollagen peptides is functioning in this disease. It is suggested that the level of biologically active procollagen peptides is lowered.