Analysis of non enzymatic glycosylation in vivo: Impact of different dialysis solutions

Background: Glucose-containing dialysis solutions in peritoneal dialysis (P D) patients induce non enzymatic glycosylation (NEG) within the peritoneal cavity. The subsequent formation of advanced glycosylation endproducts (AGE s) may be implicated in the functional deterioration of the peritoneal memb rane in long-term PD patients. Aim of the Study and Parameters: Measurement of NEG by the determination of percent glycation of albumin and IgG (GP), and of AGEs by measuring pentos idine content of protein in 4-hour effluents (Peff) and serum. Subjects: In 5 patients each, a comparison was made between 3.86% glucose a nd 1.36% glucose (GP and Peff), and between 3.86% glucose and 7.5% icodextr in (Peff). Nine patients with clinically severe ultrafiltration failure (UF F) were compared to nine patients treated with PD for 1 month. Six of the p atients with UFF were treated with non glucose dialysis solutions and Peff was studied again after 6 weeks. Results: No difference was found between Peff comparing 3.86% glucose to ei ther 1.36% glucose or icodextrin. GP were higher in 3.86% glucose than in 1 .36%. Glycated/non glycated (G/NG) protein clearance ratios were 1.29 for a lbumin and 1.12 for IgG (p = 0.003). In contrast to GP, both Peff and serum pentosidine were higher in the UFF patients than in the recently started p atients. Peff, but not GP, correlated with duration of PD (r = 0.67, p = 0. 04). In 5 of 6 patients treated with non glucose dialysate, Peff decreased while serum pentosidine was stable. Discussion:These data show that 4-hour Peff contents are not influenced by glucose concentration or osmolality, in contrast to GP. The relation betwee n Peff and duration of PD, and the effect of non glucose dialysate on Peff, suggest that long-term glucose exposure is an important determinant of mem brane glycosylation. Thus Peff probably reflects the long-term effects of i ntraperitoneal glycosylation of peritoneal membrane proteins. Treatment wit h non glucose dialysis solutions may result in "wash-out" of glycosylated p roteins from the peritoneal membrane.