Fibroblast activation in scleroderma.

Skin fibroblast cultures started from 6 scleroderma patients and 5 controls were compared with respect to synthesis of collagen and glycosaminoglycans. Fibroblast strains started from skin biopsy material from patients with active localized disease exhibited appreciably increased synthesis of collagen, whereas cultures from old sclerodermatous areas showed normal or decreased rates for collagen synthesis. During subculturing, all fibroblast strains with a high initial rate of collagen synthesis exhibited a gradual decline to near-normal values by the 12th in vitro passage. No similar alterations were detected in glycosaminoglycan metabolism. The results suggest that fibroblast activation in scleroderma is due to exogenous factors; in cell culture their effects are lost and activation disappears.