Adaptive Changes in GFR, Tubular Morphology and Transport in Subtotal Nephrectomized Kidneys: Modeling and Analysis.

Adaptive Changes in GFR, Tubular Morphology and Transport in Subtotal Nephrectomized Kidneys: Modeling and Analysis. Am J Physiol Renal Physiol. 2017 Mar 22;:ajprenal.00018.2017 Authors: Layton AT, Edwards A, Vallon V Abstract Removal of renal mass stimulates anatomical and functional adaptations in the surviving nephrons, including elevation in single-nephron glomerular filtration rate (SNGFR) and tubular hypertrophy. A goal of this study is to assess the extent to which the concomitant increases in filtered load and tubular transport capacity preserve homeostasis of water and salt. To accomplish that goal, we developed computational models to simulate solute transport and metabolism along nephron populations in a uninephrectomized (UNX) rat and a 5/6-nephrectomized (5/6-NX) rat. Model simulations indicate that nephrectomy-induced SNGFR increase and tubular hypertrophy go a long way to normalize excretion, but alone are insufficient to fully maintain salt balance. We then identified increases in the protein density of \Red{Na$^+$/K$^+$-ATPase,} Na$^+$/K$^+$-2Cl$^-$ cotransporter (NKCC2), Na$^+$-Cl$^-$ cotransporter (NCC), and epithelial Na$^+$ channel (ENaC) such that the UNX and 5/6-NX models predict urine flow and urinary Na$^+$ and K$^+$ excretions that are similar to sham levels. The models predict that in the UNX and 5/6-NX kidneys fractional water and salt reabsorption is similar to sham along the initial nephron segments (i.e...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research