Increased levels of transforming growth factor beta 1 and basic fibroblast growth factor in patients on CAPD: a study during non-infected steady state and peritonitis.

Long-term influence of continuous ambulatory peritoneal dialysis (CAPD) on concentrations of transforming growth factor beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF) in the peritoneal effluent, and the effect of peritonitis on these cytokines were investigated. TGF-beta1 and bFGF were assayed in effluent samples from dialysate bags collected during the initial week of treatment with CAPD and at 5 months. To determine the effect of peritonitis, dialysate bags were collected on admission to the hospital and on days 3 and 10 and also during non-infected steady state. Serum was drawn prior to infection and on days 1 and 10. TGF-beta1 increased more than threefold during the longitudinal follow-up period, median concentrations of 35 pg/ml to 106 pg/ml (P<0.05). No change in bFGF was seen during this initial 5 months. TGF-beta1 was increased on the first day of peritonitis (median concentration 169 pg/ml) and reached its maximum on day 3 of infection, (median concentration 216 pg/ml) (P<0.05 vs non-infected state, median concentration 39 pg/ml). Basic FGF reached a maximum on day three of infection (median concentration 7.7 pg/ml; P=0.01 vs non-infected state) and then slowly declined. In conclusion, TGF-beta1 is influenced by CAPD treatment per se, and together with bFGF is increased during peritonitis, indicating its importance in the peritoneum and its potential involvement in the development of tissue fibrosis and eventually ultrafiltration failure.