Plasma advanced glycosylation end-products in maintenance haemodialysis patients

BACKGROUND Pentosidine is a useful marker of advanced glycation end-products (AGE) which form cross-links between proteins and have been found elevated in plasma and tissues of uraemic and haemodialysed subjects. The origin and fate of these molecules are not clearly understood, but they might play a role in the cardiovascular complications of end stage renal failure. The aim of this study was to evaluate the effect of different types of substitutive therapy on the removal of pentosidine. METHODS Pentosidine was measured by a two-step HPLC methodology. Its concentration was evaluated in plasma before and after dialysis session, in 24-h urine, and in dialysate of subjects treated with three types of chronic substitutive therapy: bicarbonate haemodialysis, acetate-free biofiltration, and haemofiltration. Pentosidine levels were compared among the three therapy modalities and correlated with clinical and biochemical parameters. RESULTS Plasma pentosidine level was extremely high (23.7 +/- 2.0 pmol/mg protein) in the patients treated with the different dialysis modalities. The dialysis session had no significant effect on its plasma concentration, but haemofiltration seemed to be the most efficient method (300-2000 nmol of pentosidine removed per session versus 250-700 nmol per session with the two other approaches). An interesting correlation was found between pentosidine and blood urea nitrogen (r = 0.58, P < 0.01) and pentosidine with uric acid (r = 0.48, P < 0.05). CONCLUSIONS These results suggest that none of the methodology showed a good removal of pentosidine, but among them haemofiltration has the best efficiency. The statistical relationships between pentosidine and urea and uric acid respectively might provide insight into the origin of pentosidine. The accumulation of reactive AGE in uraemic patients may be implicated in the organ and tissue damage observed in uraemia.