Intravital imaging of the kidney in a rat model of salt-sensitive hypertension

Hypertension is one of the most prevalent diseases worldwide and a major risk factor for renal failure and cardiovascular disease. The role of albuminuria, a common feature of hypertension and robust predictor of cardiorenal disorders, remains incompletely understood. The goal of this study was to investigate the mechanisms leading to albuminuria in the kidney of a rat model of hypertension, the Dahl salt-sensitive (SS) rat. To determine the relative contributions of the glomerulus and proximal tubule (PT) to albuminuria, we applied intravital two-photon-based imaging to investigate the complex renal physiological changes that occur during salt-induced hypertension. Following a high-salt diet, SS rats exhibited elevated blood pressure, increased glomerular sieving of albumin (GSCalb = 0.0686), relative permeability to albumin (+16%), and impaired volume hemodynamics (–14%). Serum albumin but not serum globulins or creatinine concentration was decreased (–0.54 g/dl), which was concomitant with increased filtration of albumin (3.7 vs. 0.8 g/day normal diet). Pathologically, hypertensive animals had significant tubular damage, as indicated by increased prevalence of granular casts, expansion and necrosis of PT epithelial cells (+2.20 score/image), progressive augmentation of red blood cell velocity (+269 µm/s) and micro vessel diameter (+4.3 µm), and increased vascular injury (+0.61 leakage/image). Therefore, development of salt-induced hypertension can b...
Source: AJP: Renal Physiology - Category: Urology & Nephrology Authors: Tags: RESEARCH ARTICLE Source Type: research