Enhanced expression of TGF-beta 1 by peritoneal macrophages in CAPD patients.

Peritoneal macrophages are the predominant cells in peritoneal dialysate. To clarify the role of the macrophage in fibrosis of the peritoneum in long-term continuous ambulatory peritoneal dialysis (CAPD) patients, we studied the transforming growth factor beta (TGF-beta 1) mRNA expression by peritoneal macrophages from peritoneal dialysis patients. Macrophages were obtained when the catheter was inserted and one month later. TGF-beta 1 mRNA was measured by slot-blot hybridization using a cDNA probe. The result was that TGF-beta 1 expression was significantly higher in macrophages from peritoneal dialysate than that of macrophages obtained during catheter insertion. This suggests that peritoneal macrophages play a role in the pathogenesis of fibrosis of peritoneum in peritoneal dialysis patients. It also suggests that peritoneal macrophages in dialysate have been somewhat activated.