Renal Hemodynamic, Functional and Metabolic Changes After AGEs (Advanced Glycation End Products) Load by Positron Emission Tomography (PET) and Blood Oxygen Level-Dependent (BOLD) - MRI. The AGE- Functional Reserve Study.

Renal functional reserve is defined as the glomerular hyper filtration induced by a protein load. Renal blood flow and Glomerular Filtration Rate (GFR) increase in response to a protein load. Renal functional reserve loss is associated with a persistent hyper filtration state, seen in first stages of diabetic nephropathy, leading to progression of Chronic Kidney Disease (CKD). This observation has lead to larger clinical studies that demonstrated the positive effects of protein restriction on kidney function, and allowed the scientific community to recommend low proteins diet (less than 0.8 g / kg/ day) to prevent CKD progression. Nevertheless, the precise mechanisms responsible for kidney hemodynamic and metabolic changes induced by a protein load, are debated. Uribarri et al have suggested that renal hemodynamic changes induced by a protein load are mainly due to the Advanced Glycation End Products (AGEs) content. Indeed, initial studies experimental conditions leading to the demonstration of renal functional reserve (amino acid or protein perfusion or cooked meat), were in fact responsible for an AGEs load, based on recent published data.

The aim of this study is to determine whether AGEs alone or proteins in general are responsible for the mobilization of renal functional reserve, leading to the progression of CKD.