Biocompatibility of Peritoneal Dialysis Fluids

The various studies cited here clearly demonstrate that peritoneal dialysis solutions reduce the viability of leukocytes and mesothelial cells, and compromise their capacity for phagocytosis, bacterial killing, and production of cytokines. The inhibitory capacity of the CAPD fluids appears to be related to their low pH, high osmolality, and high glucose concentrations. In some of the experimental settings, lactate was also identified as suppressive factor, but only at low pH. In clinical CAPD, the pH is rapidly buffered following the dialysate instillation, and the high glucose concentrations and osmolality are also partially equilibrated. Nevertheless, for a certain period of time following the dialysate exchange, peritoneal host defense systems are exposed to an unphysiological environment known to compromise important immune-cell functions. Moreover, certain leukocyte properties, such as the production of cytokines, are impaired even following longer i.p. dwell periods. Thus conventional CAPD solutions induce an at least transitory impairment of peritoneal host defense, reflecting a bioincompatibility of the commercial CAPD fluids and underscoring the need for developing fluids with a more physiological formulation.