Changes in glycation and oxidation markers in patients starting peritoneal dialysis: A pilot study

Background: The high incidence of cardiovascular disease in uremic patients makes it a major cause of morbidity and mortality in those patients. Uremia is associated with carbonyl and oxidative stress, which result in the enhanced formation of glycation and oxidation products respectively. In the present study, the blood levels of advanced glycation end products (AGEs) and advanced oxidation protein products (AOPPs) were investigated in uremic patients prior to and after initiation of peritoneal dialysis (PD). Methods: 22 patients [11 nondiabetic (G1) and 11 diabetic (G2) subjects] were enrolled in a singte-center prospective study. Prior to starting PD (TO) and 6 and 12 months later, changes in AGE and AOPP levels were analyzed in the total study population and in each group (Friedman test, intragroup). At each time point, a comparison was made between the levels of the above-mentioned products in G1 and G2 (Mann-Whitney test, intergroup). Correlations between AGE or AOPP levels and residual renal function, peritoneal creatinine clearance, glucose peritoneal equilibration test, or daily dextrose exposure were analyzed using the Pearson test. Results: At TO, no significant difference was found between the two groups for AGE or AOPP levels. Initiation of PD was followed by an increase in AGE levels in all patients (p < 0.01 at 6 and 12 months). AGE levels were higher in G2 than in G1 at 12 months after the start of PD (p < 0.05). In contrast to G2 results, initiation of PD in G1 led to reduced AOPP levels (at 6 and 12 months, p = 0.01 and p < 0.05 respectively). However, no correlation between AGE or AOPP levels and residual renal function, peritoneal creatinine clearance, glucose peritoneal equilibration test, or daily dextrose exposure could be established. Conclusion: This study demonstrates that PD is associated with an increase in levels of blood glycation end products, particularly in diabetic patients, but also with a decrease in oxidative products such as AOPPs, especially in nondiabetic subjects.