Peritoneal dialysis: a biological membrane with a nonbiological fluid.

During chronic peritoneal dialysis (PD), the peritoneal membrane undergoes structural and functional alterations that, in some patients, may eventually lead to loss of function as the 'dialysis membrane'. These alterations include loss of mesothelial cells, thickening of the submesothelial compact zone, and changes of vascularization. At least some of these effects are thought to be associated with chronic exposure to unphysiological PD fluids. On a cellular level, chronic PD is associated with the phenomenon of epithelial-to-mesenchymal transformation (EMT) as well as premature aging and senescence of mesothelial cells. The present article discusses the potential mechanisms involved in these phenomena and reviews the current information derived from cell culture and animal studies.