In vitro cytotoxicity of four different buffers for use in peritoneal dialysis

Various buffers can be used in fluids for peritoneal dialysis (PD). Lactate is the most frequently used buffer, but bicarbonate and pyruvate have been suggested as more biocompatible alternatives. In the past, acetate was use d as a buffer in PD fluids, but was abandoned after being linked with scler osing peritonitis and loss of ultrafiltration. When a new buffer for PD flu ids is introduced, one of its most important characteristics is that it mus t be non-toxic, i.e. that it does not influence fundamental cellular functi ons. The aim of this study was to investigate the basal cytotoxicity of bic arbonate, acetate, lactate and pyruvate at neutral pH. As target cells, we used cultured mouse fibroblast-like L-929 cells, a well-known cell line app roved by the authorities for regulatory use, and primary human mesothelial cells, which are the cells that line the peritoneal cavity and are exposed to the PD fluid in vivo. Pyruvate was more cytotoxic than lactate and bicar bonate, and no significant difference in cytotoxicity was found between lac tate and bicarbonate. The human mesothelial cells were more sensitive to ex posure to pyruvate than the L-929 fibroblast-like cells, but less sensitive to exposure to pure PD fluids. Thus, we recommend that both types of cell are used for the evaluation of the biocompatibility of PD fluids.