FIBROBLAST FUNCTION IN PSORIATIC-ARTHRITIS .1. ALTERATION OF CELL-KINETICS AND GROWTH-FACTOR RESPONSES

Objective. To explore the potential role of fibroblasts in the pathoge nesis of psoriasis and its related arthritis. Specifically, we analyze d the cell cycle of psoriatic fibroblasts obtained from skin and synov ium by flow cytometry, and we also studied their response to several g rowth factors. Methods. Fibroblast cultures were established from norm al and psoriatic skin, uninvolved and involved, and synovium. NIH-3T3 cells were also used as indicator cells in some of the experiments. Fi broblasts DNA cell cycle analysis was performed by flow cytometry, and the data was analyzed by using the ''Cytologic DNA applications softw are version 2.'' In addition, fibroblasts were stimulated with growth factors including epidermal growth factor, transforming growth factor- beta, and platelet derived growth factor. Results. A significant incre ase of S and G2-M phase values in confluent cultures of psoriatic fibr oblasts in both skin and synovium compared to normal fibroblasts was f ound. Psoriatic fibroblasts also exhibited a greater proliferative res ponse to growth factors compared to normal fibroblasts. Conclusion. Da ta obtained clearly showed a significant intrinsic in vitro alteration in skin and synovium fibroblasts from patients with psoriasis.