ROLE OF PERITONEAL MESOTHELIAL CELLS AND FIBROBLASTS IN THE SYNTHESISOF HYALURONAN DURING PERITONEAL-DIALYSIS

Objective: To assess the in vitro synthesis rate of hyaluronan (HA) by human peritoneal mesothelial cells and peritoneal fibroblasts in the presence of effluent dialysate from continuous ambulatory peritoneal d ialysis (CAPD) patients.Methods:We used primary cultures of human peri toneal mesothelial cells and peritoneal fibroblasts from nonuremic pat ients to study the effect of interleukin-1 beta (Il-1 beta) and pooled effluent dialysate, from noninfected and infected CAPD patients, on t he synthesis of HA by the studied cells. We also tested the effect of the exogenous HA on the synthesis rate of that glycosaminoglycan. We s tudied the correlation between HA concentration in effluent dialysate and the stimulatory effect of that solution on in vitro synthesis of H A by mesothelium. Results: Peritoneal fibroblasts produce more HA than mesothelial cells. Noninfected effluent dialysates or dialysates from CAPD patients with peritonitis stimulate synthesis of HA by mesotheli al cells and fibroblasts. Interleukin-lp has a stimulating effect, whi ch was synergistic with effluent dialysates, on the synthesis of HA by mesothelium and peritoneal fibroblasts. A weak correlation was demons trated between the level of HA in effluent dialysate and the stimulato ry effect of that dialysate on in vitro synthesis of HA by mesothelial cells. Conclusions: Peritoneal fibroblasts are a more potent source o f HA than are mesothelial cells, but probably the latter are the main source of HA in drained dialysate. Although effluent dialysates contai n factors that stimulate the production of HA by mesothelium, there is weak correlation between that stimulatory effect and the actual HA co ncentration in the dialysate, which, in some patients, might suggest l ow ''responsiveness'' of the membrane.