The Influence of Increased Tubular Hydrostatic Pressure on Renal Function

Abstract

The effect of tubular obstruction on renal function has been understood poorly at the tubular level and from the clinical standpoint. In our review the evidence for a direct influence of hydrostatic pressure on tubular transport and glomerular filtration is examined. The data generated to date indicate a direct influence of hydrostatic pressure on tubular transport only at the level of the distal convoluted tubule and collecting duct. With respect to glomerular filtration increased tubular pressure reduces the net driving force for filtration and reduces glomerular filtration rate in the absence of a compensatory increase in glomerular hydrostatic pressure. We next review physiological data concerning the mechanism of post-obstructive diuresis. Available information suggests 4 factors that play a significant role in the clinical syndrome of post-obstructive diuresis: 1) medullo-papillary washout, 2) decreased fractional and absolute salt and water reabsorption in the collecting duct, presumably secondary to direct influence of hydrostatic pressure on transport mechanisms, 3) osmotic diuresis secondary to retention of urea and other osmotic solutes during the period of obstruction and 4) prior salt and water administration in the absence of excretion, resulting in extracellular fluid volume expansion.

Serum and urinary NGAL but not KIM‐1 raises in human postrenal AKI

“…Nevertheless, a significant de novo synthesis in distal nephrons of the obstructed kidney was observed as well [29]. A de novo synthesis in the distal nephron may as well contribute to the significant increase of sNGAL and uNGAL in our patients, as direct influence of hydrostatic pressure on tubular transport occurs at the level of the distal convoluted tubule and collecting duct [30].…”

“…Herein, hydrostatic pressure effecting distal nephron segments and collecting ducts may thus hardly influence uKIM-1 expression in the short run. Therefore, we conclude that solely acute postrenal obstruction, affecting mainly distal parts of the nephron [30], does not sufficiently induce a marked increase in uKIM-1. Accordingly, levels of uKIM-1 observed in our renal colic patients, and the healthy control group were not significantly different.…”

“…uKIM-1 is exclusively expressed in the apical membrane of the proximal tubule [31] of injured epithelial cells [32]. Therefore, we conclude that solely acute postrenal obstruction, affecting mainly distal parts of the nephron [30], does not sufficiently induce a marked increase in uKIM-1. Therefore, we conclude that solely acute postrenal obstruction, affecting mainly distal parts of the nephron [30], does not sufficiently induce a marked increase in uKIM-1.…”

“…This may explain the lower striking raise in uNGAL compared with sNGAL. A de novo synthesis in the distal nephron may as well contribute to the significant increase of sNGAL and uNGAL in our patients, as direct influence of hydrostatic pressure on tubular transport occurs at the level of the distal convoluted tubule and collecting duct [30]. In a mouse model of unilateral obstruction, NGAL was highly but transiently accumulated in the serum, filtrated and reabsorbed in the contralateral kidneys [29].…”

Clases, subclases y marcadores genéticos en las inmunoglobulinas del mieloma múltiple en Colombia

“…El alivio de la obstrucción urinaria bilateral conduce generalmente a una rápida mejoría de la oliguria y de la retención nitrogenada; sin embargo, presenta también problemas serios en el manejo clínico del paciente (Tabla 4). Frecuentemente se observa una marcada poliuria postobstructiva (11), una marcada pérdida de sodio y de potasio y una deficiencia variable en la acidificación de la orina (12); además, la filtración glomerular disminuye y en ocasiones no regresa a la normalidad, especialmente cuando la obstrucción ha sido prolongada (13). Las gráficas 1 y 2, correspondientes a los dos primeros casos Gráfica 2-Caso No.…”