Fibroblast function in psoriatic arthritis. I. Alteration of cell kinetics and growth factor responses.

To explore the potential role of fibroblasts in the pathogenesis of psoriasis and its related arthritis. Specifically, we analyzed the cell cycle of psoriatic fibroblasts obtained from skin and synovium by flow cytometry, and we also studied their response to several growth factors.Fibroblast cultures were established from normal and psoriatic skin, uninvolved and involved, and synovium. NIH-3T3 cells were also used as indicator cells in some of the experiments. Fibroblasts DNA cell cycle analysis was performed by flow cytometry, and the data was analyzed by using the "Cytologic DNA applications software version 2." In addition, fibroblasts were stimulated with growth factors including epidermal growth factor, transforming growth factor-beta, and platelet derived growth factor.A significant increase of S and G2-M phase values in confluent cultures of psoriatic fibroblasts in both skin and synovium compared to normal fibroblasts was found. Psoriatic fibroblasts also exhibited a greater proliferative response to growth factors compared to normal fibroblasts.Data obtained clearly showed a significant intrinsic in vitro alteration in skin and synovium fibroblasts from patients with psoriasis.