AGE Content of a Protein Load Is Responsible for Renal Performances: A Pilot Study

OBJECTIVE Chronic kidney disease is associated with higher morbidity and mortality in patients with diabetes. A low-protein diet is recommended to slow diabetic nephropathy progression because each protein load leads to renal hemodynamic variations. The aim of our study was to evaluate whether the advanced glycation end products (AGE) content of a protein load is responsible for the protein-induced renal hemodynamic variations in humans. RESEARCH DESIGN AND METHODS Ten healthy subjects were assigned to a high-protein (1 g/kg) low-AGE (3,000 kU AGE) versus high-AGE (30,000 kU AGE) meal. Renal perfusion, oxygen consumption, and oxygen content were measured before and 120 min after each meal. RESULTS Renal perfusion (3.2 +/- 0.5 vs. 3.8 +/- 0.4 mL/min/g; P = 0.0002) and oxygen consumption (0.3 +/- 0.04 vs. 0.4 +/- 0.08 min(-1); P = 0.005) increased significantly after the high-AGE meal compared with the low-AGE meal. CONCLUSIONS Our results suggest that the AGE content of a protein load is responsible for renal hemodynamic modifications. Therefore, prevention of diabetic nephropathy progression could aim predominantly at reducing food AGE content.