scholarly journals Endocytic adaptation to functional demand by the kidney proximal tubule

2021 ◽  
Author(s):  
Ora A. Weisz
Keyword(s):  
Proximal Tubule ◽  
Kidney Proximal Tubule

Influence of vitamin D treatment on functional expression of drug disposition pathways in human kidney proximal tubule cells during simulated uremia

Xenobiotica ◽  
2021 ◽  
pp. 1-11
Author(s):  
Stacey M. Tuey ◽  
Amandla Atilano-Roque ◽  
Georgia Charkoftaki ◽  
Joshua M. Thurman ◽  
Thomas D. Nolin ◽  
...  
Keyword(s):  
Vitamin D ◽  
Proximal Tubule ◽  
Drug Disposition ◽  
Human Kidney ◽  
Functional Expression ◽  
Proximal Tubule Cells ◽  
Kidney Proximal Tubule ◽  
Tubule Cells

scholarly journals Serum uric acid, disease severity and outcomes in COVID-19

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Inès Dufour ◽  
Alexis Werion ◽  
Leila Belkhir ◽  
Anastazja Wisniewska ◽  
Marie Perrot ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Uric Acid ◽  
Respiratory Failure ◽  
Confidence Interval ◽  
Proximal Tubule ◽  
Disease Severity ◽  
Serum Levels ◽  
Kidney Proximal Tubule ◽  
Urate Transporter ◽  
Low Serum

Abstract Background The severity of coronavirus disease 2019 (COVID-19) is highly variable between individuals, ranging from asymptomatic infection to critical disease with acute respiratory distress syndrome requiring mechanical ventilation. Such variability stresses the need for novel biomarkers associated with disease outcome. As SARS-CoV-2 infection causes a kidney proximal tubule dysfunction with urinary loss of uric acid, we hypothesized that low serum levels of uric acid (hypouricemia) may be associated with severity and outcome of COVID-19. Methods In a retrospective study using two independent cohorts, we investigated and validated the prevalence, kinetics and clinical correlates of hypouricemia among patients hospitalized with COVID-19 to a large academic hospital in Brussels, Belgium. Survival analyses using Cox regression and a competing risk approach assessed the time to mechanical ventilation and/or death. Confocal microscopy assessed the expression of urate transporter URAT1 in kidney proximal tubule cells from patients who died from COVID-19. Results The discovery and validation cohorts included 192 and 325 patients hospitalized with COVID-19, respectively. Out of the 517 patients, 274 (53%) had severe and 92 (18%) critical COVID-19. In both cohorts, the prevalence of hypouricemia increased from 6% upon admission to 20% within the first days of hospitalization for COVID-19, contrasting with a very rare occurrence (< 1%) before hospitalization for COVID-19. During a median (interquartile range) follow-up of 148 days (50–168), 61 (12%) patients required mechanical ventilation and 93 (18%) died. In both cohorts considered separately and in pooled analyses, low serum levels of uric acid were strongly associated with disease severity (linear trend, P < 0.001) and with progression to death and respiratory failure requiring mechanical ventilation in Cox (adjusted hazard ratio 5.3, 95% confidence interval 3.6–7.8, P < 0.001) or competing risks (adjusted hazard ratio 20.8, 95% confidence interval 10.4–41.4, P < 0.001) models. At the structural level, kidneys from patients with COVID-19 showed a major reduction in urate transporter URAT1 expression in the brush border of proximal tubules. Conclusions Among patients with COVID-19 requiring hospitalization, low serum levels of uric acid are common and associate with disease severity and with progression to respiratory failure requiring invasive mechanical ventilation.

scholarly journals A Multicompartment Human Kidney Proximal Tubule-on-a-Chip Replicates Cell Polarization–Dependent Cisplatin Toxicity

2020 ◽  
Vol 48 (12) ◽  
pp. 1303-1311
Author(s):  
Tom T.G. Nieskens ◽  
Mikael Persson ◽  
Edward J. Kelly ◽  
Anna-Karin Sjögren
Keyword(s):  
Proximal Tubule ◽  
Human Kidney ◽  
Cell Polarization ◽  
Kidney Proximal Tubule

A network thermodynamic model of salt and water flow across the kidney proximal tubule

1978 ◽  
Vol 235 (6) ◽  
pp. F638-F648 ◽  
Author(s):  
S. R. Thomas ◽  
D. C. Mikulecky
Keyword(s):  
Proximal Tubule ◽  
Water Flow ◽  
Thermodynamic Model ◽  
Circuit Simulation ◽  
Basolateral Membrane ◽  
Kidney Proximal Tubule ◽  
Network Analyses ◽  
Pump Rate ◽  
Parameter Values ◽  
The Given

This network thermodynamic model of kidney proximal tubule epithelium treats coupled salt and water flow across each component membrane of the epithelium. We investigate the effects of various relative internal parameter values on the concentration of transepithelial flow, the concentrations in the cell and interspace, and the distribution of flows between cellular and paracellular routes. Best fit is obtaine if the apical and basolateral membrane reflection coefficients (or) are equal. The measured transepithelial filtration coefficient, Lp, is a function not only of the component Lps but also of the internal concentrations, or's, and permeabilities. For the given system topology (i.e., connectedness), parameters of component membranes must be within a narrow range to be consistent with experimental results. The dependence of the concentration of transported fluid on the balance between the solute pump rate and the transepithelial volume flow driving force is shown. This has implications for the effects of peritubular or lumen oncotic pressure on salt and water flow. With Appendix B of this paper and a user's guide for a circuit-simulation package (e.g., SPICE or PCAP) the reader can perform similar network analyses of transport models himself.

Identification of an apical \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Cl}^{-}{/}\mathrm{HCO}_{3}^{-}\) \end{document} exchanger in rat kidney proximal tubule

2003 ◽  
Vol 285 (3) ◽  
pp. C608-C617 ◽  
Author(s):  
Snezana Petrovic ◽  
Liyun Ma ◽  
Zhaohui Wang ◽  
Manoocher Soleimani
Keyword(s):  
Proximal Tubule ◽  
Apical Membrane ◽  
Rat Kidney ◽  
Proximal Tubules ◽  
Immunocytochemical Staining ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Kidney Proximal Tubule ◽  
Anion Transporter

SLC26A6 (or putative anion transporter 1, PAT1) is located on the apical membrane of mouse kidney proximal tubule and mediates [Formula: see text] exchange in in vitro expression systems. We hypothesized that PAT1 along with a [Formula: see text] exchange is present in apical membranes of rat kidney proximal tubules. Northern hybridizations indicated the exclusive expression of SLC26A6 (PAT1 or CFEX) in rat kidney cortex, and immunocytochemical staining localized SLC26A6 on the apical membrane of proximal tubules, with complete prevention of the labeling with the preadsorbed serum. To examine the functional presence of apical [Formula: see text] exchanger, proximal tubules were isolated, microperfused, loaded with the pH-sensitive dye BCPCF-AM, and examined by digital ratiometric imaging. The pH of the perfusate and bath was kept at 7.4. Buffering capacity was measured, and transport rates were calculated as equivalent base flux. The results showed that in the presence of basolateral DIDS (to inhibit [Formula: see text] cotransporter 1) and apical EIPA (to inhibit Na+/H+ exchanger 3), the magnitude of cell acidification in response to addition of luminal Cl– was ∼5.0-fold higher in the presence than in the absence of [Formula: see text]. The Cl–-dependent base transport was inhibited by ∼61% in the presence of 0.5 mM luminal DIDS. The presence of physiological concentrations of oxalate in the lumen (200 μM) did not affect the [Formula: see text] exchange activity. These results are consistent with the presence of SLC26A6 (PAT1) and [Formula: see text] exchanger activity in the apical membrane of rat kidney proximal tubule. We propose that SLC26A6 is likely responsible for the apical [Formula: see text] (and Cl–/OH–) exchanger activities in kidney proximal tubule.

Characterization of rat kidney proximal tubule brush border membrane-associated phosphatidylinositol phosphodiesterase

1983 ◽  
Vol 224 (2) ◽  
pp. 555-567 ◽  
Author(s):  
Dorie W. Schwertz ◽  
Jeffrey I. Kreisberg ◽  
Manjeri A. Venkatachalam
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Rat Kidney ◽  
Kidney Proximal Tubule

scholarly journals Cloning of monkey RALDH1 and characterization of retinoid metabolism in monkey kidney proximal tubule cells

2002 ◽  
Vol 44 (2) ◽  
pp. 303-313 ◽  
Author(s):  
Helene Brodeur ◽  
Isabelle Gagnon ◽  
Sylvie Mader ◽  
Pangala V. Bhat
Keyword(s):  
Proximal Tubule ◽  
Monkey Kidney ◽  
Proximal Tubule Cells ◽  
Kidney Proximal Tubule ◽  
Retinoid Metabolism ◽  
Tubule Cells
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