Abstract P3190: Renal Tubular Mitochondrial Akt1 Modulates Cardiorenal Metabolic Syndrome

Abstract

Metabolic syndrome-induced cardiomyopathy is a significant risk factor for cardiovascular diseases (CVDs). The proximal tubular cells of the kidney play a crucial role in regulating glucose and lipid metabolism. Mitochondrial dysfunction in these cells has been linked to the development of metabolic syndrome-induced cardiac dysfunction. AKT1, a serine/threonine protein kinase, regulates mitochondrial function. In this study, we investigated the effects of renal proximal tubular mitochondrial AKT1 on metabolic syndrome-induced cardiomyopathy in transgenic mice. We generated transgenic mouse lines, KMioxCAKT, with inducible overexpression of mitochondrial AKT1, specifically in renal proximal tubular cells. One line was induced with tamoxifen, while the other was with corn oil. Both lines were fed a high-fat diet (HFD) for 16 weeks to provoke metabolic syndrome. For renal function, although serum BUN ( p= 0.728 ) and creatinine ( p=0.622 ) were not changed, the proteinuria ( p=0.031 ) and the urine KIM-1 ( p=0.012 ) were decreased in tamoxifen-induced KMioxCAKT. The glomerulosclerosis index ( p =0.027), tubulointerstitial fibrosis score ( p =0.032), tubular dilatation score ( p =0.032), tubular vacuolation score ( p =0.031), and tubular casts ( p =0.018) of renal histology were amended in tamoxifen-induced KMioxCAKT. The fasting glucose level ( p =0.015); the 15 to 120 minutes glucose levels ( p =0.020); the fasting insulin level ( p=0.037 ), and insulin resistance measured by Homeostatic Model Assessment for Insulin Resistance ( p=0.005 ) were reduced in metabolic syndrome with augmentation of renal tubular mitochondrial AKT1. In addition, tamoxifen-induced KMioxCAKT mice had significantly attenuated cardiac hypertrophy in the heart compared to corn oil-induced KMioxCAKT. Our results suggest that enhancing renal proximal tubular mitochondrial AKT1 could ameliorate the cardiorenal metabolic syndrome.