Glycoxidation and inflammation in renal failure patients

Inflammation is common in patients with chronic renal failure and has been associated with the increased risk for cardiovascular disease (CVD) in this condition. Advanced glycoxidation end products (AGEs) are among the factors implicated in the inflammatory state of chronic renal failure.

In a cross-sectional study of 189 dialysis patients, we measured circulating levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), vascular adhesion molecule-1 (VCAM-1), vascular endothelial growth factor (VEGF), and plasminogen activator inhibitor-1 (PAI-1) to test for possible relationships between them and serum AGE levels. In addition, these parameters were measured in a subgroup of 18 patients with chronic renal failure randomly assigned to a 4-week diet, either low (L-AGE) or high (H-AGE) in AGE content. AGEs were measured by means of a monoclonal antibody against epsilonN-carboxymethyllysine.

At baseline, serum AGE levels, as well as those for CRP, TNF-alpha, VCAM-1, and VEGF, were markedly elevated, although no correlation was found between AGE levels and the other markers. Dietary AGE modulation resulted in a significant decrease in levels of serum AGEs, CRP, and PAI-1 in the L-AGE group (approximately 35%, 44%, and 17%, respectively; P < 0.03), whereas only serum AGE levels increased significantly in the H-AGE group. VCAM-1 and TNF-alpha levels, although similar at baseline, became significantly lower in patients on an L-AGE compared with H-AGE diet (P < 0.05) at the end of the study.

Data from the interventional phase of the study suggest that AGEs have a role in the initiation of the inflammatory state of chronic renal failure, which eventually leads to increased CVD. This finding opens the possibility for using anti-AGE strategies in the prevention and treatment of CVD in patients with chronic renal failure.