ADVANCED GLYCATION END-PRODUCTS IN THE PERITONEAL-FLUID AND IN THE PERITONEAL MEMBRANE OF CONTINUOUS AMBULANT PERITONEAL-DIALYSIS PATIENTS

In patients on continuous ambulant peritoneal dialysis (CAPD) treatmen t, the peritoneal membrane is continuously exposed to the high glucose concentration contained in the dialysate. This may lead to the local generation of advanced glycation end-products (AGEs). To test this hyp othesis we evaluated the plasma and dialysate AGE concentrations in fi ve CAPD patients. The dialysate was measured after a 1 h and after a 1 2 h dwell time. Additionally, in two patients an immunohistochemical i nvestigation of the peritoneal membrane for AGE was performed. For the determination of AGE an ELISA using a polyclonal antibody against AGE bovine serum albumin was used; the immunohistochemical staining was p erformed using the streptavidin-biotin complex method. We found only l ow concentrations of AGE in the dialysate after a 1 h dwell time; afte r 12 h, however, the dialysate AGE was even greater than the plasma co ncentration. In both peritoneal specimens we found positive staining f or AGE in the interstitium of the mesothelial layer. The dialysate AGE contained a high proportion of high-molecular-weight AGE proteins, an d low-molecular-weight AGE was found to be in the same concentration r ange as the total serum ACE. We conclude that there is local generatio n of AGE in the peritoneal membrane and a 'washing out' of AGE from th e peritoneal membrane during longer dwell times. We speculate that the accumulation of AGE might lead to some of the functional and morpholo gical alterations observed after long-term CAPD.