In Patients with Chronic Kidney Disease Advanced Glycation End-Products Receptors Isoforms (sRAGE and esRAGE) Are Associated with Malnutrition

Background: in patients with chronic kidney disease (CKD), the inflammatory and pro-oxidant milieu may contribute to malnutrition development. In this study, we investigated the relationship between inflammation, advanced glycation end-products (AGEs), and their receptors (RAGEs) with malnutrition in CKD patients. Methods: we evaluated 117 patients. AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer, soluble RAGEs isoforms, and inflammatory interleukins by ELISA. Malnutrition was assessed by a malnutrition inflammation score. Results: mean age was 80 +/- +11 years, eGFR was 25 +/- +11 mL/min/1.73 m(2) and BMI was 28 +/- 5 Kg/m(2). Malnourished individuals were older, had lower estimated protein intake (nPCR 0.65 +/- 0.2 vs. 0.8 +/- 0.2 vs. 0.8 +/- 0.3, p = 0.01), higher C reactive protein (CRP 0.6 +/- 1 vs. 0.6 +/- 0.7 vs. 0.17 +/- 0.13, p = 0.02) and tumor necrosis factor alpha (TNF alpha 14.7 +/- 8.7 vs. 15.6 +/- 8 vs. 11.8 +/- 5.8, p = 0.029). Malnourished patients had higher sRAGE (2813 +/- 1477 vs. 2158 +/- 1236 vs. 2314 +/- 1115, p = 0.035) and esRAGE (648 [408-1049] vs. 476 [355-680] vs. 545 [380-730] p = 0.033). In the multivariate analysis, only sRAGE maintained its association with malnutrition (p = 0.02) independently of aging and inflammation. Conclusions: in CKD patients, RAGEs isoforms, but not AGEs, are associated with malnutrition, irrespective of systemic inflammation, aging, and renal function.