The role of mesothelial cell biology in peritoneal fibrosis on CAPD
thesisposted on 15.12.2014, 10:29 by James Frederick. Medcalf
Worldwide 100,000 people are dependent on peritoneal dialysis (PD) for treatment of end-stage renal failure. Long term technique survival is limited by peritoneal membrane fibrosis and loss of membrane function. The human peritoneal mesothelial cell (HPMC) is the one of the most abundant cells in the peritoneal cavity, and is in direct contact with the peritoneal dialysate. The aim of these experiments was to investigate the role of the HPMC in the regulation of peritoneal fibrosis in the context of peritoneal dialysis.;Hyperosmolar glucose lactate-buffered dialysate is the most widely used dialysis solution. A culture system was developed to grow HPMC from uraemic patients undergoing PD catheter insertion. The effect exposure to a 50:50 mixture of dialysate and M199 for 12 hours was examined. Glucose was varied between 5-40mmol/L. Increases in glucose concentration caused a decrease in cell viability, a decrease in proliferation, and increase in fibronectin mRNA and protein amount.;The mechanism responsible for glucose induced increase in fibronectin was examined. Increasing glucose caused an increase in HPMC TGF- protein amount. Exogenous TGF- caused a dose dependent increase in HPMC fibronectin production, and increase mRNA for fibronectin and TGF- itself. An anti TGF- Antibody prevented glucose induced HPMC fibronectin production.;Two alternative dialysis solutions were investigated; a different osmotic agent (amino acid dialysate), and a different dialysate buffer (bicarbonate). Amino acid dialysate showed less cytotoxicity, but inhibited proliferation, and caused TGF- mediated fibronectin production. Although amino acid dialysate contains 3.3 mmo1/L L-arginine, NO was not shown to mediate this response. Dialysate with bicarbonate:lactate buffer allowed greater HPMC proliferation, and no inhibition of proliferation with hyperosmolar glucose previously seen with lactate buffered dialysate.;These studies suggest the HPMC has a role in the production and regulation of ECM, and that TGF- is an important intermediary.