Erythrocytes alter the pattern of renal hypoxic injury: predominance of proximal tubular injury with moderate hypoxia

1989 ◽  
Vol 76 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Zoltan H. Endre ◽  
Peter J. Ratcliffe ◽  
John D. Tange ◽  
David J. P. Ferguson ◽  
George K. Radda ◽  
...  
Keyword(s):  
Oxygen Delivery ◽  
Rat Kidney ◽  
Proximal Tubules ◽  
Thick Ascending Limb ◽  
Tubular Injury ◽  
Total Oxygen ◽  
Hypoxic Injury ◽  
Nephron Segment ◽  
Proximal Tubular

1. The distribution of morphological injury was assessed qualitatively and quantitatively in the perfused rat kidney in vitro at controlled rates of oxygen delivery in the presence of low concentrations of erythrocytes. 2. In control kidneys (total oxygen delivery approximately 32 μmol/min per kidney) no injury was seen in the medullary thick ascending limb of Henle's loop (MTAL) whilst 11 ± 5 (sd)% of proximal tubules sustained damage. 3. Mild hypoxia (total oxygen delivery approximately 28 μmol/min per kidney) produced little or no injury to MTAL, namely 6 ± 4(sd)% and 3 ± 3% of tubules damaged, respectively. In contrast, both groups sustained extensive damage to proximal tubules, averaging 46 ± 13% (P < 0.01 vs control) and 84 ± 14% (P < 0.001 vs control), respectively. This damage was equally distributed between the superficial and deep cortex. 4. Comparison with morphometric data obtained previously from cell-free-perfused rat kidneys [P. J. Ratcliffe, Z. H. Endre, S. J. Scheinman, J. D. Tange, J. G. G. Ledingham & G. K. Radda (1988) Clinical Science74, 437–448] showed that (a) erythrocytes prevent hypoxic damage to the MTAL at mild and moderate levels of hypoxia; (b) when oxygen delivery rates are matched between cell-free- and erythrocyte-perfused kidneys, proximal tubular injury is greater in the presence of erythrocytes; (c) when arterial partial pressure of oxygen is matched between cell-free- and erythrocyte-perfused kidneys, the degree of proximal tubular injury is similar. 5. The data suggest that the proximal tubule and not the MTAL is the nephron segment most at risk of hypoxic injury in vitro.

Expression of Na-P(i) cotransport in rat kidney: localization by RT-PCR and immunohistochemistry

1994 ◽  
Vol 266 (5) ◽  
pp. F767-F774 ◽  
Author(s):  
M. Custer ◽  
M. Lotscher ◽  
J. Biber ◽  
H. Murer ◽  
B. Kaissling
Keyword(s):  
Transport System ◽  
Polyclonal Antibodies ◽  
Rat Kidney ◽  
Proximal Tubules ◽  
Expression Cloning ◽  
Kidney Cortex ◽  
Thick Ascending Limb ◽  
Rt Pcr ◽  
Rat Kidney Cortex ◽  
Proximal Tubular

We have recently identified a rat kidney cortex Na-dependent transport system for phosphate (P(i)) by expression cloning (NaP(i)-2) (S. Magagnin, A. Werner, D. Markovich, V. Sorribas, G. Stange, J. Biber, and H. Murer. Proc. Natl. Acad. Sci. USA 90: 5979, 1993). In this study we have used reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry to establish the sites of expression of the NaP(i)-2-related mRNA and protein. RT-PCR was performed with single microdissected nephron segments. From these experiments we conclude that NaP(i)-2 mRNA is predominantly expressed in the proximal tubules of superficial and deep nephrons. No NaP(i)-2 mRNA was detected in the thick ascending limb of Henle's loop; however, faint NaP(i)-2 related PCR products were also observed in collecting ducts. Expression of the NaP(i)-2 protein was examined with the use of polyclonal antibodies raised against synthetic NaP(i)-2-derived peptides. Strong specific anti-NaP(i)-2 antiserum-mediated immunofluorescence was found in the convoluted part of proximal tubules and gradually decreased along the straight part. Immunofluorescence indicated that the NaP(i)-2 protein is present in the brush border of proximal tubular cells. In addition, NaP(i)-2-specific immunofluorescence was also observed in subapical vesicles. The described distribution of the NaP(i)-2 protein is in agreement with previously described nephron sites of P(i) reabsorption in the rat kidney and therefore suggests that the NaP(i)-2 transport system represents an Na-P(i) cotransporter involved in proximal tubular apical transport of phosphate.

Tubular handling of neurotensin in the rat kidney as studied by micropuncture and HPLC

1989 ◽  
Vol 256 (1) ◽  
pp. F100-F106
Author(s):  
T. Bjerke ◽  
E. I. Christensen ◽  
N. Boye
Keyword(s):  
High Performance ◽  
Rat Kidney ◽  
Proximal Tubules ◽  
Urinary Recovery ◽  
Rat Serum ◽  
Proximal Tubular ◽  
Distal Tubules ◽  
Extensive Degradation ◽  
Convoluted Tubules

Micropuncture studies were performed to assess the reabsorption and metabolism of the vasoactive peptide neurotensin (NT) in individual nephron segments and compare it to the handling of the closely related peptide bradykinin (BK). Rat proximal and distal convoluted tubules were microinfused with [3H]NT or [3H]BK. In a second set of experiments, [3H]NT and its metabolites in the ureteral urine were separated and characterized using high-performance liquid chromatography (HPLC) technique. The urinary recovery of 3H-labeled material was 31% when proximal tubules were microinfused with [3H]NT and 94% when distal tubules were infused. For proximal tubules the label recovered in the ureteral urine consisted exclusively of metabolites of NT and appeared as tyrosine, NT1-11, probably NT9-13, and two uncharacterized products. For distal tubules, 9% chromatographed as intact NT in the urine and except for the proportion the metabolites were almost identical to those found when proximal tubules were microinfused. Following microinfusion of [3H]BK into proximal tubules, the urinary recovery of 3H-labeled material was 19%. There was no correlation between fractional reabsorption of 3H-labeled material and proximal tubular length when [3H]NT or [3H]BK was microinfused. In vitro incubation studies with rat ureteral urine showed extensive degradation of NT yielding tyrosine, NT1-6, probably NT9-13, NT, and two uncharacterized products. In contrast, there was no detectable breakdown of BK over a 32-min period. Finally, [3H]NT was incubated in rat serum, and these experiments also showed degradation of the peptide but not to the extent as when incubated in ureteral urine.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Developmental changes in rabbit proximal straight tubule paracellular permeability

2002 ◽  
Vol 283 (3) ◽  
pp. F525-F531 ◽  
Author(s):  
Raymond Quigley ◽  
Michel Baum
Keyword(s):  
Proximal Tubule ◽  
Chloride Transport ◽  
Chloride Concentration ◽  
Chloride Ions ◽  
Proximal Tubules ◽  
Chloride Permeability ◽  
Proximal Straight Tubule ◽  
Nephron Segment ◽  
Proximal Tubular

The early proximal tubule preferentially reabsorbs organic solutes and bicarbonate over chloride ions, resulting in a luminal fluid with a higher chloride concentration than that in blood. From this late proximal tubular fluid, one-half of NaCl reabsorption by the adult proximal tubule is active and transcellular and one-half is passive and paracellular. The purpose of the present in vitro microperfusion study was to determine the characteristics of passive chloride transport and permeability properties of the adult and neonatal proximal straight tubules (PST). In tubules perfused with a late proximal tubular fluid, net passive chloride flux was 131.7 ± 37.7 pmol · mm−1 · min−1in adult tubules and −17.1 ± 23.3 pmol · mm−1 · min−1 in neonatal proximal tubules ( P < 0.01). Chloride permeability was 10.94 ± 5.21 × 10−5 cm/s in adult proximal tubules and −1.26 ± 1.84 × 10−5 cm/s in neonatal proximal tubules ( P< 0.05). Thus neonatal PST have a chloride permeability not different from zero and have no net passive chloride transport. Bicarbonate permeability is also less in neonates than adults in this segment (−0.07 ± 0.03 × 10−5 vs. 0.93 ± 0.27 × 10−5 cm/s, P < 0.01). Neonatal PST have higher sodium-to chloride and bicarbonate-to-chloride permeability ratios than adult PST. However, mannitol and sucrose permeabilities were not different in adult proximal tubules and neonatal PST. Transepithelial resistance was measured using current injection and cable analysis. The resistance was 6.7 ± 0.7 Ω · cm2 in adult tubules and 11.3 ± 1.4 Ω · cm2 in neonatal PST ( P < 0.01). In conclusion, there are significant maturational changes in the characteristics of the PST paracellular pathway affecting transport in this nephron segment.

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.

Immunolocalization of NHE8 in rat kidney

2005 ◽  
Vol 288 (3) ◽  
pp. F530-F538 ◽  
Author(s):  
Sunita Goyal ◽  
SueAnn Mentone ◽  
Peter S. Aronson
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Rat Kidney ◽  
Surface Membrane ◽  
Proximal Tubules ◽  
Intense Staining ◽  
Proximal Tubule Cells ◽  
Nephron Segment ◽  
Tubule Cells

In situ hybridization studies demonstrated that Na+/H+ exchanger NHE8 is expressed in kidney proximal tubules. Although membrane fractionation studies suggested apical brush-border localization, precise membrane localization could not be definitively established. The goal of the present study was to develop isoform-specific NHE8 antibodies as a tool to directly establish the localization of NHE8 protein in the kidney by immunocytochemistry. Toward this goal, two sets of antibodies that label different NHE8 epitopes were developed. Monoclonal antibody 7A11 and polyclonal antibody Rab65 both specifically labeled NHE8 by Western blotting as well as by immunofluorescence microscopy. The immunolocalization pattern in the kidney seen with both antibodies was the same, thereby validating NHE8 specificity. In particular, NHE8 expression was observed on the apical brush-border membrane of all proximal tubules from S1 to S3. The most intense staining was evident in proximal tubules in the deeper cortex and medulla with a significant but somewhat weaker staining in superficial proximal tubules. Colocalization studies with γ-glutamyltranspeptidase and megalin indicated expression of NHE8 on both the microvillar surface membrane and the coated-pit region of proximal tubule cells, suggesting that NHE8 may be subject to endocytic retrieval and recycling. Although colocalizing in the proximal tubule with NHE3, no significant alteration in NHE8 protein expression was evident in NHE3-null mice. We conclude that NHE8 is expressed on the apical brush-border membrane of proximal tubule cells, where it may play a role in mediating or regulating ion transport in this nephron segment.

Regional and segmental localization of AE2 anion exchanger mRNA and protein in rat kidney

1995 ◽  
Vol 269 (4) ◽  
pp. F461-F468 ◽  
Author(s):  
F. C. Brosius ◽  
K. Nguyen ◽  
A. K. Stuart-Tilley ◽  
C. Haller ◽  
J. P. Briggs ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Rat Kidney ◽  
Chloride Concentration ◽  
Transepithelial Transport ◽  
Thick Ascending Limb ◽  
Cortical Collecting Duct ◽  
Base Exchange ◽  
Medullary Thick Ascending Limb ◽  
Nephron Segment ◽  
Medullary Collecting Duct

Chloride/base exchange activity has been detected in every mammalian nephron segment in which it has been sought. However, in contrast to the Cl-/HCO3- exchanger AE1 in type A intercalated cells, localization of AE2 within the kidney has not been reported. We therefore studied AE2 expression in rat kidney. AE2 mRNA was present in cortex, outer medulla, and inner medulla. Semiquantitative polymerase chain reaction of cDNA from microdissected tubules revealed AE2 cDNA levels as follows [copies of cDNA derived per mm tubule (+/- SE)]: proximal convoluted tubule, 688 +/- 161; proximal straight tubule, 652 +/- 189; medullary thick ascending limb, 1,378 +/- 226; cortical thick ascending limb, 741 +/- 24; cortical collecting duct, 909 +/- 71; and outer medullary collecting duct, 579 +/- 132. AE2 cDNA was also amplified in thin limbs and in inner medullary collecting duct. AE2 polypeptide was detected in all kidney regions. AE2 mRNA and protein were also detected in several renal cell lines. The data are compatible with the postulated roles of AE2 in maintenance of intracellular pH and chloride concentration and with its possible participation in transepithelial transport.

scholarly journals Palmitate aggravates proteinuria-induced cell death and inflammation via CD36-inflammasome axis in the proximal tubular cells of obese mice

2018 ◽  
Vol 315 (6) ◽  
pp. F1720-F1731 ◽  
Author(s):  
Lung-Chih Li ◽  
Jenq-Lin Yang ◽  
Wen-Chin Lee ◽  
Jin-Bor Chen ◽  
Chien-Te Lee ◽  
...  
Keyword(s):  
Cell Death ◽  
Tubular Injury ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Caspase 1 ◽  
Proximal Tubular ◽  
Renal Tubular ◽  
Nlrp3 Inflammasomes

High levels of serum free fatty acids (FFAs) and proteinuria have been implicated in the pathogenesis of obesity-related nephropathy. CD36, a class B scavenger receptor, is highly expressed in the renal proximal tubules and mediates FFA uptake. It is not clear whether FFA- and proteinuria-mediated CD36 activation coordinates NLRP3 inflammasomes to induce renal tubular injury and inflammation. In this study, we investigated the roles of CD36 and NLRP3 inflammasomes in FFA-induced renal injury in high-fat diet (HFD)-induced obesity. HFD-fed C57BL/6 mice and palmitate-treated HK2 renal tubular cells were used as in vivo and in vitro models. Immunohistochemical staining showed that CD36, IL-1β, and IL-18 levels increased progressively in the kidneys of HFD-fed mice. Sulfo- N-succinimidyl oleate (SSO), a CD36 inhibitor, attenuated the HFD-induced upregulation of NLRP3, IL-1β, and IL-18 and suppressed the colocalization of NLRP3 and ASC in renal tubular cells. In vitro, SSO abolished the palmitate-induced activation of IL-1β, IL-18, and caspase-1 in HK2 proximal tubular cells. Furthermore, treatment with SSO and the knockdown of caspase-1 expression by siRNA both inhibited palmitate-induced cell death and apoptosis in HK2 cells. Collectively, palmitate causes renal tubular inflammation, cell death, and apoptosis via the CD36/NLRP3/caspase-1 axis, which may explain, at least in part, the mechanism underlying FFA-related renal tubular injury. The blockade of CD36-induced cellular processes is therefore a promising strategy for treating obesity-related nephropathy.

ABSORPTION OF 125I-LABELLED SHEEP GROWTH HORMONE IN SINGLE PROXIMAL TUBULES OF THE RAT KIDNEY

1976 ◽  
Vol 68 (1) ◽  
pp. 21-NP ◽  
Author(s):  
B. D. STACY ◽  
A. L. C. WALLACE ◽  
R. T. GEMMELL ◽  
B. W. WILSON
Keyword(s):  
Growth Hormone ◽  
Renal Cortex ◽  
Rat Kidney ◽  
Alternative Pathway ◽  
Proximal Tubules ◽  
Lysosomal Degradation ◽  
Electron Microscope Autoradiography ◽  
Microscope Autoradiography ◽  
Kidney Micropuncture

SUMMARY Techniques of kidney micropuncture and electron microscope autoradiography have been used to study the uptake of 125I-labelled sheep growth hormone (GH) in rat renal proximal tubules. After microperfusion of a proximal tubule with 125I-labelled GH, the transport of label by the tubular epithelium was studied autoradiographically at selected times up to 1 h. The sequential transfer of labelled material from tubule to microvilli, then to small and large apical vacuoles and finally to lysosomes followed the pattern of absorption that has been described for other proteins. Evidence of lysosomal degradation of the transported protein was obtained from studies in vitro; lysosomes isolated from the renal cortex rapidly converted 125I-labelled GH to products of lower molecular weight. In addition to the absorptive pathway through the intracellular vacuolar apparatus it appeared that there was also an alternative pathway, less well defined, whereby GH could be absorbed without being degraded.

Iodine concentrations in the rat kidney measured by x-ray microanalysis

1998 ◽  
Vol 39 (1) ◽  
pp. 90-95 ◽  
Author(s):  
J. Ueda ◽  
A. Nygren ◽  
M. Sjöquist ◽  
E. Jacobsson ◽  
H. R. Ulfendahl ◽  
...  
Keyword(s):  
Renal Pelvis ◽  
Filtration Rate ◽  
Rat Kidney ◽  
Iodine Concentration ◽  
Proximal Tubules ◽  
The Other ◽  
X Ray ◽  
Single Nephron ◽  
Proximal Tubular ◽  
Puncture Technique

Purpose: To measure the iodine concentrations in the proximal tubules and renal pelvis after i.v. injections of contrast media (CM) at 1600 mg I/kg b.w., using a micro-puncture technique and X-ray microanalysis Material and Methods: The correlation between the viscosity of each CM and its iodine concentration was evaluated and the viscosity of the fluid in the proximal tubule and renal pelvis was estimated in rats Results: After iotrolan injection, the iodine concentration in the proximal tubular fluid had increased to values about three times higher than those reached with diatrizoate, iohexol and ioxaglate. Similarly, iotrolan tended to produce a higher iodine concentration in the renal pelvis than did the other CM. the urine viscosity in the renal pelvis was much higher after the iotrolan injection than after the other CM injections Conclusion: High urine viscosity after iotrolan injection can at least partly explain our previous findings of a prolonged increase in tubular hydrostatic pressure and a prolonged decrease in the single nephron glomerular filtration rate after administration of this CM

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