BACKGROUND: Peritubular endothelium plays a key role in the development and progression of diabetic and nondiabetic chronic kidney disease. Renal injury in disorders of glucose metabolism may appear as early as in the stage of impaired glucose tolerance (IGT) and is accelerated by hypertension. The aim of our study was to investigate renal histology in rats with hypertension and IGT, with special emphasis on the peritubular endothelium. METHODS: Hypertension and IGT (H/IGT) were provoked in adult male Wistar rats by bilateral administration of methylglyoxal into the ventromedial hypothalamus. Immunohistochemistry with anti-renin and anti-imidazolone antibodies and immunoelectron microscopy with anti-renin antibody were performed. RESULTS: H/IGT rats showed tubulointerstitial fibrosis as well as renin and imidazolone staining in the papillary region. The patterns of immunostaining for renin and imidazolone were similar to that of endothelium. On electron microscopy, peritubular capillary endothelial cells and to a less extent, tubular epithelial cells showed renin positivity. DISCUSSION: Impaired glucose tolerance complicated with hypertension leads to tubulointerstitial fibrosis in rat kidney. Imidazolone deposition and renin production in peritubular capillary endothelial cells may play a role in the development of tubulointerstitial fibrosis.
BACKGROUND: Peritubular endothelium plays a key role in the development and progression of diabetic and nondiabetic chronic kidney disease. Renal injury in disorders of glucose metabolism may appear as early as in the stage of impaired glucose tolerance (IGT) and is accelerated by hypertension. The aim of our study was to investigate renal histology in rats with hypertension and IGT, with special emphasis on the peritubular endothelium. METHODS:Hypertension and IGT (H/IGT) were provoked in adult male Wistar rats by bilateral administration of methylglyoxal into the ventromedial hypothalamus. Immunohistochemistry with anti-renin and anti-imidazolone antibodies and immunoelectron microscopy with anti-renin antibody were performed. RESULTS: H/IGT rats showed tubulointerstitial fibrosis as well as renin and imidazolone staining in the papillary region. The patterns of immunostaining for renin and imidazolone were similar to that of endothelium. On electron microscopy, peritubular capillary endothelial cells and to a less extent, tubular epithelial cells showed renin positivity. DISCUSSION: Impaired glucose tolerance complicated with hypertension leads to tubulointerstitial fibrosis in rat kidney. Imidazolone deposition and renin production in peritubular capillary endothelial cells may play a role in the development of tubulointerstitial fibrosis.