[The effect of cyclosporin A (CyA) on the growth and metabolic activity of gingival fibroblasts].

Cyclosporine A (CyA) is a powerful nonsteroidal immunosuppressive agent in organ and bone marrow transplants. It may cause nephro- and hepatotoxicity and may lead to generalized fibrous hyperplasia of gingiva by a yet unknown mechanism. In order to study the pathophysiology of this side effect human gingival fibroblast cultures derived from normal gingiva were studied under the influence of CyA. During short time incubation of 72 h a significant increase of 3H-thymidine incorporation was noted while 14C-glucosamine incorporation remained unchanged. Long term incubation over 6 weeks, however, resulted in a significant increase of both cell proliferation and synthesis of the extracellular matrix. These findings demonstrate a powerful growth stimulation of gingival fibroblasts by CyA under in-vitro conditions and show that the observed fibrous hyperplasia of the gingiva under CyA therapy is the result of a direct effect on gingival cells.