Chronic effects of dietary protein in the rat with intact and reduced renal mass

Abstract

The chronic effects of dietary protein on renal structure and function were studied in rats with normal and reduced renal mass. Control rats with two kidneys were compared with unilaterally nephrectomized rats, and with one and one-third nephrectomized rats obtained by unilateral nephrectomy and infarction of one-third of the remaining kidney. Rats at each level of renal mass were maintained on chow containing either 6% or 40% protein content. Separate cohorts of rats were studied four and eight months after ablation and institution of these dietary regimens. At both time intervals and at all levels of renal mass, rats fed the high protein diet had higher average values for GFR than comparable animals fed the low protein chow. Within each of the dietary regimens the animals with loss of renal mass developed greater prevalences of sclerotic glomeruli by eight months. Furthermore, at each level of initial renal mass, rats eating the high protein diet had a greater prevalence of sclerotic glomeruli than those on the low protein diet. Similarly, rats on the high protein diet had greater rates of protein excretion than those on the low protein diet at each degree of ablation. The prevalence of sclerosed glomeruli increased between four and eight months in each group. Thus, the extent of renal injury as manifested by proteinuria and glomerular sclerosis was directly related to the degree of initial loss of renal mass, and dietary protein restriction retarded these manifestations of injury across a wide range of initial renal mass.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium Sensitivity of Blood Pressure Appearing Before Hypertension and Related to Histological Damage in Immunoglobulin A Nephropathy

“…In rats with experimental nephritis or 1-sided nephrectomy, glomerular hypertension appears without hypertension. 21,22,25,26 The glomerular pressure in our patients with normal to high-normal pressure may be higher than that in our patients with optimal pressure. We calculated the glomerular pressure in the patients of this study by the method used in our previous study.…”

Advanced Glycation End Products and Nephrotoxicity of High-Protein Diets

“…Disturbances in renal hemodynamics were among the earliest abnormalities observed when protein intake was increased (5). In physiologic studies that were performed with classic micropuncture techniques, rats that were fed a high-protein diet were found to have high GFR as a result of increased glomerular perfusion and pressure (6). Persistent glomerular hypertension was shown to mediate progressive renal injury in rat models of diabetes and reduced renal mass (6,7).…”

Role of Fermentable Carbohydrate Supplements in the Course of Uremia

“…Studies in CRF patients (randomized trial or not) reported that starting a restriction of dietary protein and phosphate early in the course of CRF has a considerable influence on the rate of progression of this disease (Mitch, 1991 ;Levey et al, 1996aLevey et al, , 1996bWilliam & Maroni, 1998 ;Mackenzie & Brenner, 1998, Garneata & Mircescu, 2010Kalista-Richards, 2011;Fouque et al, 2011a). In experimental models, dietary protein restriction reduces the load of N metabolism end-products for excretion, limits the adaptive changes in remnant nephrons, and slows the tendency to renal disease progression (Hostetter, 1986). Despite the unambiguous support from experimental studies, the conclusive results are often regarded as unconvincing and as they do not meet strict statistical rules (Gretz & Strauch, 1986;Garneata & Mircescu, 2010).…”