Increased Glomerular Hydrostatic Pressure is Associated with Tubular Creatinine Reabsorption in Healthy Subjects

Abstract

<b><i>Background:</i></b> Cr is secreted by the proximal tubules and thus Cr clearance (<i>C</i><sub>cr</sub>) can overestimate inulin clearance (<i>C</i><sub>in</sub>). However, in some cases, <i>C</i><sub>cr</sub> can even underestimate <i>C</i><sub>in</sub>. This suggests that Cr could be reabsorbed in the tubuli. We examined the clinical parameters that are associated with tubular Cr reabsorption. <b><i>Methods:</i></b> In 80 kidney donor candidates (53.9 ± 13.2 years, 29 males), <i>C</i><sub>in</sub> and para-aminohippuric acid clearance were measured simultaneously. Intrarenal hemodynamic parameters were calculated by Gomez’s formulae. To quantify the secretory component of <i>C</i><sub>cr</sub> (SF<sub>cr</sub>), it was calculated as follows: SF<sub>cr</sub> = (<i>C</i><sub>cr</sub> − <i>C</i><sub>in</sub>)/<i>C</i><sub>cr</sub>. <b><i>Results:</i></b> Twenty-five subjects (31.3%) showed SF<sub>cr</sub> values <0. SF<sub>cr</sub> that correlated significantly and negatively with efferent arteriolar resistance (<i>R</i><sub>e</sub>) and glomerular hydrostatic pressure (<i>P</i><sub>glo</sub>) (<i>R</i><sub>e</sub>: <i>r</i> = −0.30, <i>p</i> = 0.008; <i>P</i><sub>glo</sub>: <i>r</i> = −0.28, <i>p</i> = 0.025). In multiple regression analyses, <i>R</i><sub>e</sub> and <i>P</i><sub>glo</sub> were significantly and negatively associated with SF<sub>cr</sub> after adjustment for other confounders. <b><i>Conclusions:</i></b> These findings suggest that tubular reabsorption of Cr can occur in some cases. Intrarenal glomerular hemodynamic burden may be related to tubular creatinine reabsorption, which possibly leads to lower <i>C</i><sub>cr</sub> values.

Drug-Induced Nephrotoxicity: A Review

“…The relative vasoconstriction and vasodilation of these efferent and afferent arterioles determine the pressure within each glomerulus. This is known as the glomerular blood hydrostatic pressure (GBHP), which is responsible for filtering fluid and molecules out of the glomerular capillaries into the tubular lumen of the nephron 13 . According to Pottel (2017), approximately 120 ml of plasma is filtered in the glomerulus per minute to maintain the glomerular filtration rate in the kidneys 14 .…”

“…The resistance of the filtrate movement into the tubule increases the pressure within the proximal tubule as the tubular cells are damaged. The rendered functioning of the proximal tubule and tubular cytotoxicity ultimately results in nephrotoxicity 13 .…”

Association of Noise Annoyance with Measured Renal Hemodynamic Changes

“…The assessment of renal hemodynamic parameters has been described in detail in former studies [20][21][22][23][24][25]. Briefly, glomerular filtration rate (GFR) and renal plasma flow (RPF) were assessed using the constant-infusion input clearance technique with infusion of inulin (Sinistrin, Inutest ® 25% Amp; Fresenius Kabi, Austria) and para-aminohippuric acid (Sodium-para-aminohippurate Injection ® 10%; Daiichi-Sankyo, Tokyo, Japan), respectively.…”

“…Renal vascular resistance was calculated as mean arterial BP/ renal blood flow × 1,000. Intraglomerular pressure and resistances of the afferent and efferent arterioles were calculated based on the Gomez equation [26], which has been applied in previous studies [21,23,25,27]. tributed parameters, the nonparametric test (Mann-Whitney U test) was used for further analysis.…”

Variable Power Functional Dilution Adjustment of Spot Urine

“…49-51 In contrast to tubular secretion, reabsorption of creatinine is considered rare, even though it has been observed in some cases, like in newborns and the very elderly. 46…”