Glucose degradation products in peritoneal dialysis fluids: do they harm?

BACKGROUND: Severe limitations in biocompatibility of conventional peritoneal dialysis fluids (PDF) can be partially attributed to the presence of glucose degradation products (GDP), which are generated during autoclaving of PDF. Formation of GDP can be significantly reduced by the use of multi-chamber bag systems. Recent clinical studies have revealed increased dialysate levels of pro-collagen I C-terminal peptide (PICP) in patients dialyzed with these solutions. Here, we briefly review the current knowledge on various aspects of GDP toxicity toward peritoneal cells and analyze the impact of GDP on PICP release by human peritoneal mesothelial cells (HPMC) in vitro.
METHODS: HPMC were exposed to a mixture of known GDP added to culture medium at clinically relevant doses. After 12 days, the amount of PICP released was measured using an immunoassay. Furthermore, the protein synthesis was assessed by 3H-proline incorporation in HPMC exposed to peritoneal effluent obtained from patients after three months of CAPD with either conventional PDF or low-GDP solution.
RESULTS: Exposure to GDP resulted in a significant decrease in PICP release by HPMC. In addition, the synthesis of new proteins secreted by HPMC was preserved significantly better in HPMC treated with effluent obtained when patients were dialyzed with low-GDP solutions rather than conventional PDF.
CONCLUSIONS: Exposure to GDP may impair protein synthesis and secretion by HPMC. Therefore, increased dialysate PICP levels in response to GDP-free PDF may be viewed as evidence of improved mesothelial cell function.