GLYCATED ALBUMIN IN SERUM AND DIALYSATE OF PATIENTS ON CONTINUOUS AMBULATORY PERITONEAL-DIALYSIS

1. Chronic use of hyperosmolar glucose solutions in continuous ambulat ory peritoneal dialysis may cause glycation of peritoneal structural p roteins which could contribute to membrane dysfunction and ultrafiltra tion failure. To determine whether glycation can occur in the environm ent of the dialysate, we have carried out studies using albumin as a m odel protein. 2. Glycated albumin was measured in the serum and dialys ate of 46 patients on continuous ambulatory peritoneal dialysis (31 no n-diabetic patients, 15 diabetic patients). Dialysate and serum glycat ed albumin (ranges 1.0-12.7% and 0.9-10.2%, respectively) were related to each other (r=0.988, P<0.001), but dialysate glycated albumin was significantly higher than serum glycated albumin (P<0.0001), with the dialysate to serum glycated albumin ratio being greater than unity in 76% of patients (mean ratio 1.14). This implies either preferential tr ansfer of glycated albumin across the peritoneal membrane or intraperi toneal glycation during the dwell period. 3. In vitro, significant gly cation occurred in dialysate during a 6h incubation period (P<0.01) at a rate related to the glucose concentration in the dialysate (r(s)=0. 63, P<0.05). The glycation rate was not significantly affected (P=0.05 ) by factors other than the glucose concentration. 4. Our results demo nstrate that protein glycation occurs within the peritoneum during con tinuous ambulatory peritoneal dialysis. Further studies are required t o establish the relationship of glycation of structural proteins in th e peritoneal membrane to membrane function.