Body Composition Changes in the Subtotally Nephrectomized Rat Fed Differing Dietary Proteins

Abstract

Changes in body composition are found in chronic uraemia, but it is unclear if this results from poor nutrient intake or is a consequence of impaired renal function. To investigate this question, 31 female Wistar rats were allocated to undergo subtotal nephrectomy or sham operation and were fed diets of either 24% casein or 24% soya protein. Three months later measurements of inulin clearance were undertaken in the conscious animal and the carcass subsequently analyzed for body water and body fat. Subtotally nephrectomized animals had a significantly greater proportion of body water (p < 0.001) and a lesser proportion of body fat (p < 0.001) than control animals, and a significant correlation was found between glomerular filtration rate and body fat content (24% casein diet: r = 0.96; 24% soya diet: r = 0.71). The dietary protein source appeared not to influence the body composition. These results support the concept that altered body composition in uraemia is due to renal dysfunction rather than altered nutrient intake.

Fat redistribution and adipocyte transformation in uninephrectomized rats

“…Rats with uninephrectomy developed chronic proteinuria in association with massive deposits of lipids, which were shown to consist mainly of free and esterified cholesterol, 23 as have prior studies in subtotally nephrectomized animals demonstrated a significant correlation between glomerular filtration rate and body fat content. 24 Consistent with the present study, the renal impairments and lipid deposition were generally prevented by ACEI treatments in Nagase analbuminemic rats, after 5/6 nephrectomy, which usually exhibit severe glomerulosclerosis, persistent hypercholesterolemia, and massive lipid deposition. 25 Additionally, clinical studies using computed tomography have previously demonstrated a significant decrease in body fat area and subcutaneous adipose tissue in parallel to an increase in visceral fat mass associated with disturbance of the serum lipid profile in non-diabetic hemodialysis patients.…”

Short-term effects of soy protein diet in patients with proteinuric glomerulopathies

“…23 In rats, it seems to be well-established the ability of soy protein to reduce proteinuria and, consequently, to lower the progression of renal disease. 4,24 Tovar et al 3 observed, in male Wistar rats that were receiving a soy protein diet (20%), a considerable recovery of creatinine clearance and a significant decrease in proteinuria compared with rats that were fed with casein (20%). Some investigators 14,24,25 have shown lower renal damage and proteinuria in rats fed with soy protein than those with casein.…”