Abnormal cellular property of fibroblasts from congenital gingival fibromatosis.

Two strains of cultured cells were isolated and characterized from the gingiva of two siblings with congenital gingival fibromatosis. The growth rate of both fibroblast strains was slower than that of comparable cells obtained from the normal gingiva of control individuals. The amounts of substances, including collagen and glycosaminoglycans, biosynthesized by the diseased cells were much greater than those by the control cells from normal gingivae. Namely, 11.7-13.7% of the protein synthesized by diseased cells was collagen, whereas collagen accounted for only 6.1-8.5% of the total protein produced by normal cells. Moreover, the production of a large amount of extracellular substances by the diseased cells was confirmed by electron microscopic examination. These observations suggest that the fibromatosis tissues contain affected fibroblasts which have low growth activity but are active in the production of much greater amounts of collagen and other extracellular substances compared to normal fibroblasts.