Attenuation of age‐dependent chronic kidney disease by soy (691.1)

Abstract

Age is an important predictor of chronic kidney disease (CKD), with a projected incidence of 11% in the adult population of the United States. Common pathways leading to CKD involve renal fibrosis and glomerular disease. Previous studies from our lab show that CKD is detectable in aging male Fisher 344 rats at 16 months of age. Therefore, we fed our rats a 10% low‐fat protein diet containing soy protein or a control diet of casein beginning at 16 months to test whether a dietary intervention of soy, begun after initiation and detection of CKD, would slow progression. The rats were fed the diet for 4 months before sacrifice. The animals on the soy diet had improved kidney function as compared to the casein diet animals, including a decrease in proteinuria, decreased urinary Kim‐1 and improved glomerular filtration rate (GFR). We found that the soy diet significantly reduced several renal fibrosis markers, including total hydroxyproline content and expression of several collagen genes, including collagen, type 1, alpha 1, collagen alpha‐2(I) chain, collagen alpha‐1(III) chain and collagen alpha‐1(IV) chain. Lastly, the soy diet animals also showed a decrease in chemokine (C‐C motif) ligands 5, 17, 19 and 21 (CCL5, CCL17, CCL19 and CCL21), which are linked to the pathogenesis of fibrosis. Taken together, this data shows that even after CKD is detectable a high soy protein diet can significantly attenuate age‐dependent renal dysfunction.