Localization of imidazolone in the peritoneum of CAPD patients: A factor for a loss of ultrafiltration

The presence of dicarbonyl compounds, potent precursors of advanced glycati on end products (AGEs), has been recognized in unused peritoneal dialysis ( PD) fluids. Accumulation of AGEs has been implicated in the alteration of p eritoneal membrane properties during continuous ambulatory peritoneal dialy sis (CAPD) therapy. To determine whether imidazolone, an AGE specifically d erived from 3-deoxyglucosone (3-DG), contributes to a decrease In ultrafilt ration (UF) capacity of the peritoneal membrane in CAPD patients, we immuno histochemically evaluated the localization of imidazolone In peritoneal tis sues from CAPD patients. Mesothelial thickening in the peritoneum was found in six of seven CAPD patients. Imidazolone distinctly accumulated in perit oneal tissues of CAPD patients, whereas it was hardly detected in those of patients with nonrenal disease. CAPD patients with a low UF capacity showed more extensive peritoneal deposition of imidazolone and more pronounced me sothelial thickening than those with a normal UF capacity. A CAPD patient w ith sclerosing peritonitis showed the most abundant localization of imidazo lone among all CAPD patients. Gas chromatography/mass spectrometry showed t hat unused PD fluids contained high 3-DG concentrations (mean, 34.6 +/- 14. 1 [SD] mug/mL). In conclusion, the accumulation of imidazolone was noted in peritoneal tissues of CAPD patients, which preceded a decrease in UF capac ity. Imidazolone modification may alter the quality of peritoneal membranes , presumably leading to a loss of UF and finally the development of scleros ing peritonitis. (C) 2001 by the National Kidney Foundation, Inc.