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Wei J, Song J, Jiang S, Zhang G, Wheeler D, Zhang J, Wang S, Lai EY, Wang L, Buggs J, Liu R. Role of intratubular pressure during the ischemic phase in acute kidney injury. Am J Physiol Renal Physiol 2016; 312:F1158-F1165. [PMID: 28579560 DOI: 10.1152/ajprenal.00527.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 10/19/2016] [Accepted: 10/31/2016] [Indexed: 01/25/2023] Open
Abstract
Acute kidney injury (AKI) induced by clamping of renal vein or pedicle is more severe than clamping of artery, but the mechanism has not been clarified. In the present study, we tested our hypothesis that increased proximal tubular pressure (Pt) during the ischemic phase exacerbates kidney injury and promotes the development of AKI. We induced AKI by bilateral clamping of renal arteries, pedicles, or veins for 18 min at 37°C, respectively. Pt during the ischemic phase was measured with micropuncture. We found that higher Pt was associated with more severe AKI. To determine the role of Pt during the ischemic phase on the development of AKI, we adjusted the Pt by altering renal artery pressure. We induced AKI by bilateral clamping of renal veins, and the Pt was changed by adjusting the renal artery pressure during the ischemic phase by constriction of aorta and mesenteric artery. When we decreased renal artery pressure from 85 ± 5 to 65 ± 8 mmHg, Pt decreased from 53.3 ± 2.7 to 44.7 ± 2.0 mmHg. Plasma creatinine decreased from 2.48 ± 0.23 to 1.91 ± 0.21 mg/dl at 24 h after renal ischemia. When we raised renal artery pressure to 103 ± 7 mmHg, Pt increased to 67.2 ± 5.1 mmHg. Plasma creatinine elevated to 3.17 ± 0.14 mg·dl·24 h after renal ischemia. Changes in KIM-1, NGAL, and histology were in the similar pattern as plasma creatinine. In summary, we found that higher Pt during the ischemic phase promoted the development of AKI, while lower Pt protected from kidney injury. Pt may be a potential target for treatment of AKI.
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Affiliation(s)
- Jin Wei
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Jiangping Song
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida.,State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shan Jiang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida.,Department of Physiology, Zhejiang University School of Medicine, Zhejiang, China
| | - Gensheng Zhang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida.,Department of Physiology, Zhejiang University School of Medicine, Zhejiang, China
| | - Donald Wheeler
- Department of Pathology and Cell Biology, University of South Florida College of Medicine, Tampa, Florida
| | - Jie Zhang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - Shaohui Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | - En Yin Lai
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang, China
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida
| | | | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida;
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Myers BD. Pathogenetic Processes in Human Acute Renal Failure. Semin Dial 2007. [DOI: 10.1111/j.1525-139x.1996.tb00305.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Faarup P, Holstein-Rathlou NH, Nørgaard T, Hegedüs V. Early segmental changes in ischemic acute tubular necrosis of the rat kidney. APMIS 2004; 112:192-200. [PMID: 15153161 DOI: 10.1111/j.1600-0463.2004.apm1120305.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The background and mechanisms of ischemic acute tubular necrosis are still essentially unclarified. Therefore a quantitative morphological technique was applied for evaluation of the early structural changes in different fractions of the proximal convoluted tubule in the rat renal cortex. In male pentothal-anesthetized Wistar rats (body weight 200-250 g) ischemia of the right kidney was obtained by clamping (clamp diameter 0.15 mm) the ipsilateral renal artery for varying periods of time (10 min to 6 h) followed by removal and instant freezing of the kidney in isopentane at -165 degrees C and subsequent freeze-substitution in alcohol. The microscopic slides from the kidneys were silver methenamine-PAS stained. In the segments of the proximal convoluted tubules of the nephrons, presence of nuclear pyknosis, places of denuded basement membranes and presence of exfoliated tubular cells were counted. The results were statistically treated for comparison between the extent of damage in the initial postglomerular fraction and the later tubular loops. All three parameters showed a systematic, statistically significant increased number of lesions in the initial fraction of the proximal convoluted tubule versus the subsequent loops. The distribution of the structural lesions is in accordance with the previously reported presence of a tubulo-capillary counter-current flow in the proximal convoluted tubule and, when related to the highly variable oxygen tension in the normal renal cortex of the rat, indicates that the peculiar location of the early lesions might well be determined by these functional conditions.
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Affiliation(s)
- Poul Faarup
- Institutes of Molecular Pathology and Physiology, University of Copenhagen, Denmark.
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4
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Kwon O, Nelson WJ, Sibley R, Huie P, Scandling JD, Dafoe D, Alfrey E, Myers BD. Backleak, tight junctions, and cell- cell adhesion in postischemic injury to the renal allograft. J Clin Invest 1998; 101:2054-64. [PMID: 9593761 PMCID: PMC508793 DOI: 10.1172/jci772] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Postischemic injury in recipients of 3-7-d-old renal allografts was classified into sustained (n = 19) or recovering (n = 20) acute renal failure (ARF) according to the prevailing inulin clearance. Recipients of optimally functioning, long-standing allografts and living donors undergoing nephrectomy served as functional (n = 14) and structural controls (n = 10), respectively. Marked elevation above control of fractional clearance of dextrans of graded size was consistent with transtubular backleak of 57% of filtrate (inulin) in sustained ARF. No backleak was detected in recovering ARF. To explore a structural basis for backleak, allograft biopsies were taken intraoperatively, 1 h after reperfusion in all recipients, and again on day 7 after transplant in a subset (n = 10). Electron microscopy revealed disruption of both apical and basolateral membranes of proximal tubule cells in both sustained and recovering ARF, but cell exfoliation and tubule basement membrane denudation were negligible. Histochemical analysis of membrane-associated adhesion complexes confirmed an abnormality of proximal but not distal tubule cells, marked in sustained ARF but not in recovering ARF. Staining for the zonula occludens complex (ZO-1) and adherens complex (alpha, beta, and gamma catenins) revealed diminished intensity and redistribution of each cytoskeletal protein from the apico-lateral membrane boundary. We conclude that impaired integrity of tight junctions and cell-cell adhesion in the proximal tubule provides a paracellular pathway through which filtrate leaks back in sustained allograft ARF.
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Affiliation(s)
- O Kwon
- Division of Nephrology, Stanford University School of Medicine, Stanford, California 94305, USA
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5
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Yin M, Kurvers HA, Tangelder GJ, Booster MH, Buurman WA, Kootstra G. Ischemia-reperfusion injury of rat kidney relates more to tubular than to microcirculatory disturbances. Ren Fail 1996; 18:211-23. [PMID: 8723359 DOI: 10.3109/08860229609052791] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Several pathophysiological mechanisms have been purported to be involved in the development of acute ischemic renal failure, such as impairment of tubular function and/or of the renal microcirculation. However, it has not been elucidated as yet which of these mechanisms relates to the extent of kidney damage. Besides, little is known about the time course relationship between tubular and microcirculatory disturbances during the development of ischemia-reperfusion injury. We therefore performed intravital videomicroscopy of the proximal tubules as well as the peritubular microcirculation of the rat renal cortex during the first 24 hr of reperfusion after varying lengths of warm ischemia (30 min, 30 WI group; 60 min, 60 WI group; 90 min, 90 WI group). In a separate group of animals subjected to the same protocol, the survival rate (SR) was determined. The SR in these groups were 100%, 20% and 0%, respectively. Initially, the tubular and microcirculatory changes (i.e., increased tubular diameter and reduced capillary blood flow) relate well to the length of warm ischemia as well as the SR. At a later stage of reperfusion, however, we observed that peritubular capillary blood flow and tubular diameter recovered more quickly in the 90 WI group than in the 30 WI and 60 WI groups. As a result, these parameters as obtained at 24 hr of reperfusion did not relate anymore to the survival rate. Besides, at this stage a severe loss of integrity of the tubular wall was noted in the 60 WI and 90 WI groups. These findings suggest that kidney viability is not determined by the extent of recovery of microcirculatory blood flow and/or tubular diameter during early reperfusion, but by the integrity of the tubular wall.
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Affiliation(s)
- M Yin
- Department of Surgery, University Hospital Maastricht, The Netherlands
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6
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Alejandro V, Scandling JD, Sibley RK, Dafoe D, Alfrey E, Deen W, Myers BD. Mechanisms of filtration failure during postischemic injury of the human kidney. A study of the reperfused renal allograft. J Clin Invest 1995; 95:820-31. [PMID: 7860766 PMCID: PMC295562 DOI: 10.1172/jci117732] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Postischemic filtration failure in experimental animals results primarily from depression of the transcapillary hydraulic pressure difference (delta P), a quantity that cannot be determined in humans. To circumvent this limitation we determined the GFR and each of its remaining determinants in transplanted kidneys. Findings in 12 allografts that exhibited subsequent normofiltration (group 1) were compared with those in 11 allografts that exhibited persistent hypofiltration (group 2). Determinations were made intraoperatively in the exposed graft after 1-3 h of reperfusion. GFR (6 +/- 2 vs 29 +/- 5 ml/min) and renal plasma flow by Doppler flow meter (140 +/- 30 vs 315 +/- 49 ml/min) were significantly lower in group 2 than group 1. Morphometric analysis of glomeruli obtained by biopsy and a structural hydrodynamic model of viscous flow revealed the glomerular ultrafiltration coefficient to be similar, averaging 3.5 +/- 0.6 and 3.1 +/- 0.2 ml/(min.mmHg) in group 2 vs 1, respectively. Corresponding values for plasma oncotic pressure were also similar, averaging 19 +/- 1 vs 21 +/- 1 mmHg. We next used a mathematical model of glomerular ultrafiltration and a sensitivity analysis to calculate the prevailing range for delta P from the foregoing measured quantities. This revealed delta P to vary from only 20-21 mmHg in group 2 vs 34-45 mmHg in group 1 (P < 0.001). Further morphometric analysis revealed the diameters of Bowman's space and tubular lumens, as well as the percentage of tubular cells that were necrotic or devoid of brush border, to be similar in the two groups. We thus conclude (a) that delta P depression is the predominant cause of hypofiltration in this form of postischemic injury; and (b) that afferent vasoconstriction rather than tubular obstruction is the proximate cause of the delta P depression.
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Affiliation(s)
- V Alejandro
- Division of Nephrology, Stanford University School of Medicine, California 94305
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7
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Abstract
Underperfusion of the kidneys often results in the development of ischemic acute renal failure. This review summarizes the recent developments in the understanding of the pathophysiology, diagnosis, and treatment of this serious and costly disorder that affects almost 5% of hospitalized patients.
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Affiliation(s)
- S R Hays
- University of Texas Southwestern Medical Center, Dept. of Internal Medicine, Dallas 75235-8856
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8
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Stevens PE, Gwyther SJ, Hanson ME, Boultbee JE, Kox WJ, Phillips ME. Noninvasive monitoring of renal blood flow characteristics during acute renal failure in man. Intensive Care Med 1990; 16:153-8. [PMID: 2191017 DOI: 10.1007/bf01724793] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Duplex Doppler ultrasound (DDU) was used to study the blood flow characteristics of the renal interlobar artery in 20 subjects with acute renal failure (ARF), 14 subjects with transient impairment of renal function and 23 control subjects with normal function. Renovascular resistance was assessed by pulsatility index (PI) and change in flow velocity by change in mean frequency shift (delta f). The 99% confidence intervals for PI in the three groups were 3.32-5.46, 1.58-2.34 and 0.99-1.33 respectively. Values for delta f were 0.2-0.38, 0.5-0.62 and 0.7-1.02 kHz respectively. Ten ARF patients recovered function, 99% confidence intervals for PI just prior to recovery were 0.9-1.48 and for delta f 0.52-1.02 kHz. There was increased renovascular resistance and reduced intrarenal blood flow velocity at the onset of ARF. These changes persisted during ARF; recovery of function occurred after they returned to normal. Similar, but less marked, changes were found in patients with a transient impairment of function.
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Affiliation(s)
- P E Stevens
- Department of Renal Medicine, Princess Mary's Royal Air Force Hospital, Halton, Aylesburgy, UK
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10
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Yared A, Ichikawa I. Transcapillary fluid transport in the glomerulus. Methods Enzymol 1990; 191:107-29. [PMID: 2074752 DOI: 10.1016/0076-6879(90)91010-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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11
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Pethö A, Neumann T, Vetterlein F, Schmidt G. Influence of diltiazem on postischemic microcirculation and function in the rat kidney. Microvasc Res 1989; 38:223-36. [PMID: 2607995 DOI: 10.1016/0026-2862(89)90001-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Renal microcirculation and function were studied in the unilateral clamp-induced ischemia/reperfusion model in anesthetized rats. After 60-min reperfusion fluorochromelabeled globulin was injected i.v. allowing histological determination of capillary plasma flow patterns (CPFP). In the 60-min ischemia protocol the untreated group revealed poor capillary labeling in the outer medulla (OM), whereas cortical perfusion patterns were only slightly altered. Pre- and postischemic treatment with diltiazem led to significant improvement of CPFP in the OM: 4.9% of tissue areas were lying more than 60 microns from the next perfused capillary vs 70.2% after untreated ischemia. Postischemic treatment with diltiazem proved much less effective. Inulin clearance (CIn) amounted to less than 2% of baseline values irrespective of the treatment regimen. However, in the 30-min ischemia protocol, displaying normal CPFP, preservation of CIn was evident and most effective after pre- and postischemic diltiazem treatment (53% vs 8% after untreated ischemia). Measurements of tubular function, however, did not reveal any significant improvement after diltiazem treatment. This observation and the fact that the drugs has a vasodilating effect lend support to the view that the preservation of glomerular filtration rate (GFR) is most likely mediated by vascular mechanisms. In conclusion, in this experimental model diltiazem significantly reduced postischemic disturbances of renal microcirculation occurring after prolonged periods of ischemia and was clearly efficient in maintaining GFR after shorter ischemic episodes; however, tubular function was not preserved. Our results, as well as those of other authors, strongly suggest that diltiazem causes the aforementioned effects mainly by actions at the vascular site.
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Affiliation(s)
- A Pethö
- Zentrum Pharmakologie und Toxikologie, Georg-August-Universität Göttingen, Federal Republic of Germany
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12
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Hellberg PO, Källskog TO. Neutrophil-mediated post-ischemic tubular leakage in the rat kidney. Kidney Int 1989; 36:555-61. [PMID: 2811061 DOI: 10.1038/ki.1989.230] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Neutropenia was induced in male Sprague-Dawley rats by administration of antineutrophil serum (ANS). A control group received an equal volume of inactive serum. After 45 minutes of unilateral complete renal ischemia the renal blood flow (RBF) was measured by an electromagnetic flow meter. The net filtration force (NFF) in glomerular capillaries, single nephron filtration rate (SNGFR) and frequency of tubular obstructions were estimated by a micropuncture technique. Tubular leakage was measured from the fractional recovery in the normal contralateral kidney of 3H- or 14C-inulin injected into surface proximal and distal tubules of the post-ischemic kidney. Neither ANS nor inactive serum had any influence on inulin clearance (CIn) in the normal kidney. In the post-ischemic kidney, CIn was four times higher in ANS-treated than in control animals. There was no difference in RBF, NFF, SNGFR or the frequency of tubular obstructions between neutrophil-depleted and control animals. The transtubular leakage of inulin injected into proximal tubules was substantially less in the ANS-treated than in the control group (11.3 +/- 1.5% vs. 35.1 +/- 6.5%; P less than 0.01). But distal tubular leakage was equal in the two groups. The control group showed isothenuria (350 +/- 29 mOsm.kg-1), while ANS-treated animals produced hyperosmolar urine (555 +/- 60 mOsm.kg-1; P less than 0.05). It is concluded that neutrophil granulocytes mediate post-ischemic tubular leakage, which contributes to the depression in renal clearance parameters and the inability to produce hyperosmolar urine.
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Affiliation(s)
- P O Hellberg
- Department of Physiology and Medical Biophysics, University of Uppsala, Sweden
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Wolfert AI, Laveri LA, Reilly KM, Oken KR, Oken DE. Glomerular hemodynamics in mercury-induced acute renal failure. Kidney Int 1987; 32:246-55. [PMID: 3656937 DOI: 10.1038/ki.1987.199] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
As manifest by tubular collapse and the virtual absence of flow into the glomerulotubular junction (GTJ), filtration in most nephrons (SNGFR) of rats poisoned with 9 mg/kg body wt HgCl2 16 to 28 hours earlier was virtually absent. Arterial colloid osmotic pressure (COPA) and Bowman's space pressure (PBS) were modestly depressed (P less than 0.05 or below), and mean blood pressure was reduced from 115 +/- 2 mm Hg (SEM) to 97 +/- 1 mm Hg (P less than 0.001). Glomerular capillary hydraulic pressure (Pg), 25.6 +/- 1.3 mm Hg was some 24 mm Hg lower than control (P less than 0.001) and yielded a net afferent effective filtration pressure (Pnet) of 4.1 +/- 1.2 mm Hg. Excluding three rats with values greater than 10 mm Hg, Pnet averaged 2.0 +/- 0.9 mm Hg (N = 17 rats) versus 20.0 +/- 1.8 mm Hg in controls (N = 10, P less than 0.001), the former being statistically almost indistinguishable from 0 mm Hg and barely able to support any filtration. This decrease in Pg was caused by a major increase in preglomerular resistance (RA) and a reciprocal fall in efferent arteriolar resistance (RE), the RA/RE ratio of 7.2 +/- 0.8 being fourfold higher than control (P less than 0.001). Renocortical blood flow was not different from control (P greater than 0.2). A wide spread of Pg values in individual glomeruli and the absence of tubular flow despite the appearance of i.v. injected lissamine green in a quadrant of surface glomeruli suggested the possibility of a greatly increased, glomerular capillary resistance. It is concluded that reciprocal changes in RA and RE are the immediate cause of filtration failure in this form of ARF and that, in the virtual absence of filtration, tubular leakage can play no important role. Since PBS was depressed in both the developmental and established phases of ARF, tubular obstruction appears to play no direct role in the pathogenesis of this particular model of murine acute renal failure.
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Affiliation(s)
- A I Wolfert
- Department of Medicine, McGuire Veterans Hospital, Richmond, Virginia
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Abstract
Postischemic acute renal failure (ARF) induced by cardiac surgery is commonly prolonged and may be irreversible. To examine whether persistence of postischemic, tubular cell injury accounts for delayed recovery from ARF, we studied 10 patients developing protracted (36 +/- 4 d) ARF after cardiac surgery. The differential clearance and excretion dynamics of probe solutes of graded size were determined. Inulin clearance was depressed (5.0 +/- 1.7 ml/min), while the fractional urinary clearance of dextrans (radii 17-30 A) were elevated above unity. Employing a model of conservation of mass, we calculated that 44% of filtered inulin was lost via transtubular backleak. The clearance and fractional backleak of technetium-labeled DTPA ([99mTc]DTPA, radius = 4 A) were identical to those of inulin (radius 15 A). The time at which inulin or DTPA excretion reached a maximum after an intravenous bolus injection was markedly delayed when compared with control subjects with ARF of brief duration, 102 vs. 11 min. Applying a three-compartment model of inulin/DTPA kinetics (which takes backleak into account) revealed the residence time of intravenously administered inulin/DTPA in the compartment occupied by tubular fluid and urine to be markedly prolonged, 20 vs. 6 min in controls, suggesting reduced velocity of tubular fluid flow. We conclude that protracted human ARF is characterized by transtubular backleak of glomerular ultrafiltrate, such that inulin clearance underestimates true glomerular filtration rate by approximately 50%, and by sluggish tubular fluid flow, which strongly suggests the existence of severe and generalized intraluminal tubular obstruction. Because all patients also exhibited extreme hyperreninemia (16 +/- 2 ng/ml per h) that was inversely related to inulin clearance (r value = -0.83) and urine flow (r value = -0.70), we propose that persistent, angiotensin II-mediated renal vasoconstriction may have delayed healing of the injured tubular epithelium.
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Abstract
A computerized model of creatinine kinetics was developed to predict the relationship between creatinine clearance [G(t)] and plasma creatinine concentration [C(t)] in patients with postischemic acute renal failure (ARF). A comparison of predicted to measured values in 35 episodes of ARF in 27 patients revealed three patterns of declining G(t) following an ischemic insult. Pattern A, characterized by an abrupt step decrement in G(t) following an isolated renal ischemic episode lasting minutes or hours, was observed in nine patients. It was followed invariably by an immediate ramp increment in G(t), despite which C(t) continued to increase for several days. Urinary indices during the period of increasing azotemia were consistent with the resolving stage of ARF. Patterns B (N = 15) and C (N = 11) were associated with persistent renal ischemia of long (days to weeks) duration and were respectively characterized by prolonged ramp or exponential decrements in G(t). A concurrent increase in C(t) was associated with urinary indices typical of the maintenance or sustained stage of ARF. Recovery of G(t) was observed in only two-thirds of patterns B and C cases and took the form of a ramp or exponential increment. Because G(t) and total body water were changing rapidly in ARF, changes in measured plasma creatinine levels alone failed to identify these patterns of deteriorating or improving renal function. However, when the computerized model was used in conjunction with daily measured values of C(t) and body weight and occasional estimates of G(t), the course and prognosis of ARF in individual patients were illuminated.
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Mason J, Torhorst J, Welsch J. Role of the medullary perfusion defect in the pathogenesis of ischemic renal failure. Kidney Int 1984; 26:283-93. [PMID: 6513274 DOI: 10.1038/ki.1984.171] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Experiments were performed on rats to investigate the significance of the medullary hyperemia known to follow renal ischemia. To this end, its frequency was determined, its severity was quantified, and its relation to renal function was examined early (1 to 3 hr) and later (18 hr) after 45 min of warm ischemia. All kidneys were found to have a hyperemic outer medulla early after ischemia, which was shown to develop during the period of ischemia itself, but which was found to be highly variable in its severity. The degree of hyperemia was assessed both subjectively by grading and by histometric determinations of inner stripe capillary volume. One to hours after ischemia, the severity of medullary hyperemia was reflected in all indices of renal function, the least congested kidneys showing the best function. Eighteen hours after ischemia, the degree of medullary hyperemia was reflected in all indices of renal function, except urine flow rate; the non-congested kidneys showed functional recovery and the still-congested kidneys showed worsening function. Glomerular blood flow, known to be preferentially reduced in deep nephrons 1 to 3 hr after ischemia, had normalized 18 hr after ischemia in the non-congested kidneys but was still severely and unevenly depressed in the congested kidneys. It is concluded that congestion of the outer medulla is a key event in ischemic renal failure, its occurrence is coincidental with the reduction in deep nephron perfusion and urinary concentrating power in the early and maintenance phase and its disappearance heralds the restoration of deep nephron perfusion and urinary concentrating ability in the recovery phase.
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Abstract
Oliguric acute renal failure in man is characterized by intense outer cortical vasoconstriction and a marked increase in preglomerular resistance. The degree of preglomerlar resistance change needed to cause the expected 50 to 80 percent fall in blood flow far exceeds the level that would totally abolish filtration. By contrast, equal 3.0-fold increases in both pre- and postglomerular resistance provide this same degree of ischemia but leave filtration very well maintained. Such a scenario seems unlikely, however, since it would entail a mere 15 to 25 percent decrease in preglomerular resistance vessel caliber rather than the extreme attenuation observed. By contrast, there are reasons to believe that preglomerular constriction may be accompanied by postglomerular vascular relaxation. In sum, unless cortical ischemia reflects precisely matched increases in pre- and postglomerular resistances, filtration failure is inevitable in human vasomotor nephropathy.
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Myers BD, Miller DC, Mehigan JT, Olcott CO, Golbetz H, Robertson CR, Derby G, Spencer R, Friedman S. Nature of the renal injury following total renal ischemia in man. J Clin Invest 1984; 73:329-41. [PMID: 6421876 PMCID: PMC425022 DOI: 10.1172/jci111217] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The effects of total renal ischemia (TRI) of 15-87 min duration due to suprarenal clamping of the aorta were studied in 15 mannitol-treated patients undergoing abdominal aortic surgery. 15 patients undergoing similar surgery but requiring only infrarenal clamping served as controls. 1-2 h following TRI, GFR was reduced to only 39% of that in controls, 23 +/- 5 vs. 59 +/- 7 ml/min (P less than 0.001). This could not be ascribed to impaired renal plasma flow (RPF), which was mildly reduced to 331 +/- 71 and was not different from the value in controls, 407 +/- 66 ml/min. However, impaired PAH extraction (43 +/- 7%) and isosthenuria, not present in controls, suggest a primary role for tubular injury in lowering GFR at this time. 24 h following TRI, the GFR remained depressed below controls, 45 +/- 8 vs. 84 +/- 8 ml/min (P less than 0.005), while the transglomerular sieving of neutral dextrans was significantly enhanced (radius interval, 24-40 A). A theoretical analysis of transcapillary solute exchange revealed that these findings could be largely explained by a selective reduction of either RPF (-61%) or of transmembrane hydraulic pressure difference (-18%) below control values. Alternately, a combination of these two factors with changes of smaller magnitude could explain the findings. In contrast, a selective increase in oncotic pressure or decrease of the glomerular ultrafiltration coefficient could be excluded as a cause of hypofiltration 24 h after TRI. These observations lead us to suggest that the transient azotemia observed following TRI is due to a self-limited injury to the nephron that is identical to that seen in overt and sustained forms of acute renal failure.
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Parekh N, Esslinger HU, Steinhausen M. Glomerular filtration and tubular reabsorption during anuria in postischemic acute renal failure. Kidney Int 1984; 25:33-41. [PMID: 6727128 DOI: 10.1038/ki.1984.5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Complete occlusion of the left renal artery for 60 min in the rat produced anuric acute renal failure after 1 day. Using fluorescence microscopy, a television system combined with double slit densitometry, and micropuncture techniques, tubular pressure and tubular flow rates were determined in different segments of superficial nephrons. Intratubular pressures in proximal convolutions of the postischemic kidney were largely heterogeneous due to abnormally increased flow resistance in proximal tubules which were filled with loose obstructive material. Proximal tubular pressure in the control kidney was independent of the site of its measurement and had a mean value of 14.1 mm Hg. In the postischemic kidney pressure decreased gradually along the proximal tubule, its value in the early and late segments being 16.3 and 9.7 mm Hg, respectively. Low pressure in late proximal convolutions excludes a significant flow impediment due to obstruction in more distal segments. The mean nephron filtration rate (SNGFR) obtained by extrapolation of tubular flow data was 62% of the control value, whereas tubular reabsorption was estimated to be 50% above normal. Reduced SNGFR and increased outflux caused a total reabsorption of tubular fluid within 60% of proximal convoluted tubule length. The partial reduction of SNGFR can be explained by increased pressure in early proximal convolutions and reduced glomerular plasma flow known for these kidneys, without postulating a change in glomerular permeability. Tubular obstruction and increased passive outflux in proximal tubules due to cellular damage appear to be crucial mechanisms responsible for the loss of renal function in this model of acute renal failure.
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Mason J, Welsch J, Takabatake T. Disparity between surface and deep nephron function early after renal ischemia. Kidney Int 1983; 24:27-36. [PMID: 6620850 DOI: 10.1038/ki.1983.122] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Experiments were performed using a variety of methods to assess the functional status of different nephron populations following 45 min of renal ischemia in the rat. Micropuncture techniques revealed that SNGFR and reabsorption in the surface nephrons are only modestly reduced after ischemia, whereas kidney GFR and reabsorption are more severely affected. Determinations of bolus velocity with the Hanssen technique or of glomerular blood flow with the microsphere method confirmed that both were highest in the surface nephrons, lower in the middle nephrons and lowest of all in the juxtamedullary nephrons after ischemia. It is concluded that surface nephron function is well-maintained following ischemia and that it is the functional deficiency of the deeper nephrons that is predominantly responsible for the impairment in whole kidney function. Although the pathogenic mechanism is not yet clear, neither tubular obstruction nor tubular leakage in the deeper nephrons seems to be involved. The present findings suggest that micropuncture of the surface nephrons is a technique of questionable validity for studying this type of acute renal failure, they explain the inability of the kidney to concentrate the final urine, and they predict a more pronounced deficiency in medullary than in outer cortical blood flow.
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Thurau K. Pathophysiology of the acutely failing kidney. CLINICAL AND EXPERIMENTAL DIALYSIS AND APHERESIS 1983; 7:9-24. [PMID: 6883806 DOI: 10.3109/08860228309076036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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26
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von Gise H, Klingebiel T, Mickeler E. Acute renal failure--an integrative discussion of morphologic and functional findings. KLINISCHE WOCHENSCHRIFT 1982; 60:773-86. [PMID: 7132231 DOI: 10.1007/bf01721142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The ultrastructural alterations at the nephron established in animal experiments, were also confirmed, by means of an electron-microscopic examination, in eight cases of human acute renal failure (ARF). Special consideration was given in this study to single cell alterations, particularly in proximal tubular cells, with emphasis being placed on alterations due to single cell damage in the region of the renal fluid compartments. The ultrastructural alterations of the tubular cells in ARF, suggest serious impairment of the cellular capacity for electrolyte transport and metabolic processes. The shunt paths between the tubular fluid compartment and the functional interstitium, arising from necrosis of the tubular cells or dissolution of the gap or tight junctions, were discussed in terms of their significance for the directional, active transport processes of the tubular cells for sodium chloride and the passive water flow. The morphologic findings were reviewed in light of recent findings on cellular membrane processes and electrolyte transport. A reinterpretation of the morphologic and functional findings in ARF is suggested. This takes into consideration single cell function and the integrity of the renal fluid compartments.
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Karlberg L, Källskog O, Norlén BJ, Wolgast M. Postischemic renal failure. Intrarenal blood flow and functional characteristics in the recovery phase. ACTA PHYSIOLOGICA SCANDINAVICA 1982; 115:1-10. [PMID: 7136794 DOI: 10.1111/j.1748-1716.1982.tb07039.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Intrarenal blood flow, nephron function and whole kidney function were studied in the recovery phase of acute failure induced by 45 min of warm ischemia. Analyses were made 24 h, 7 days and 28 days after the ischemic insult. At 24 h the total renal blood flow was 4.0 ml . min-1 . g-1, decreasing to 1.2 within one week. After four weeks it was normalized to 3.4 ml . min-1 . g-1. The intrarenal blood flow distribution, studied with the 86-Rb extraction method, showed the same pattern of response, with no signs of a persistent heavy reduction in the deeper parts, as was found 10 min after recirculation (Karlberg et al. 1982 a). The contralateral, nonischemic kidney responded with hyperemia in all areas 24 h after the trauma, but after 7 days the values were normal. The function of the superficial nephrons was studied with the micropuncture technique. In the initial phase mainly obstructed nephrons were found, but after four weeks the nephrons were essentially normal. After 24 h the postischemic kidneys were anuric but at 7 days urine production had started and the GFR was 0.1 ml . min-1; this improved to 0.55 ml . min-1 after 4 weeks.
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Abstract
Glomerular and tubular function were evaluated in 30 non-oliguric patients with increasing azotemia following open heart surgery. Fractional clearances (theta) of test solutes relative to that of inulin were determined. In 16 patients, theta dextran (radius 22 to 30 A) exceeded unity, a finding attributed to inulin backleak through necrotic tubules. These patients were classified as having acute renal failure; 14 subsequently required dialysis. In the remaining patients (N = 14), theta dextran was normal. These patients were considered to have prerenal failure; all recovered spontaneously. clearance of inulin (Cin) was lower in acute renal failure than in prerenal failure (12 +/- 2 versus 18 +/- 2 ml/min/1.73 m2; p less than 0.025). The apparent difference in glomerular filtration rate when Cin is used as an index was abolished, however, when Cin in acute renal failure was corrected for tubule backleak of inulin. In acute renal failure, fractional clearance of p-aminohippurate (theta PAH) was 7.1 +/- 1.0, and fractional excretion of potassium (FEk) was 160 +/- 18 percent. These findings strongly suggest that secretory ability in both proximal and terminal tubule augments, respectively, is preserved in acute renal failure. Compared with prerenal failure, the urine-to-plasma inulin ratio was lower (U/Pin = 10 +/- 1 versus 25 +/- 4; p less than 0.005) and FENa was higher (FENa = 5.1 +/- 1.5 versus 0.5 +/- 1.0 percent; p less than 0.01) in acute renal failure.
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Karlberg L, Källskog O, Norlén BJ, Wolgast M. Nephron function in postischemic acute renal failure. SCANDINAVIAN JOURNAL OF UROLOGY AND NEPHROLOGY 1982; 16:167-72. [PMID: 7123168 DOI: 10.3109/00365598209179748] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Acute renal failure was induced in rats by clamping the renal artery for 45 min. After reestablishing renal blood flow, tubular heterogeneity was observed, with (1) seemingly normal tubules, (2) dilated tubules and (3) collapsed tubules. Micropuncture techniques were used to examine the hydrostatic pressures in the different nephrons and superficial vessels, and also to determine single nephron glomerular filtration rate. The dilated tubules showed minimal filtration, due to an elevated intratubular pressure probably caused by obstructions; in these nephrons filtration could be induced by lowering the intratubular pressure. In the "normal" nephrons there was some filtration, as the proximal tubular pressure was only moderately increased. No filtration took place in the collapsed type, probably as a result of glomerular ischemia and consequently decreased glomerular capillary pressure. The kidneys also exhibited isosthenuric polyuria with a reduced potassium secretion. It is suggested that a medullary ischemia will lead to interstitial and intracellular edema and eventually cell necrosis with subsequent formation of obstructions in the loops of Henle. The obstructions would explain the increase in proximal tubular pressure and the decrease in total kidney filtration to about 5% of the normal. It is proposed that the deficient urine concentration ability and the inhibited potassium secretion are caused by the ischemic damage to the renal medulla.
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Myers BD, Hilberman M, Carrie BJ, Spencer RJ, Stinson EB, Robertson CR. Dynamics of glomerular ultrafiltration following open-heart surgery. Kidney Int 1981; 20:366-74. [PMID: 6170777 DOI: 10.1038/ki.1981.148] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
To elucidate how individual determinants might lower the rate of glomerular ultrafiltration (GFR) in some patients following cardiac surgery, we performed hemodynamic measurements and clearance of inulin (as a measure of GFR), PAH (as a measure of effective renal plasma flow [ERPF]), and dextran-40. Two groups of 17 patients each were distinguished by the presence or absence of prerenal azotemia. Glomerular hypofiltration (GFR = 21 +/- 2 vs. 76 +/- 6 ml/min/1.73 m2, P less than 0.001) in the former was accompanied by depressed left ventricular function, arterial pressure, and ERPF (152 +/- 26 vs. 317 +/- 32 ml/min/1.73 m2, P less than 0.001). To determine if factors beside ERPF play a role in lowering GFR, we calculated the efferent oncotic pressure (pie). Failure of GFR to change over a 24-hour period despite increases in ERPF suggested that both patient groups were at filtration pressure disequilibrium (FPD). This condition permits calculation of a unique glomerular ultrafiltration coefficient (Kf). Over a range of pressures for transcapillary hydraulic pressure (deltaP), such that 3 less than or equal to (deltaP - pie) less than or equal to 10 mm Hg (to simulate FPD), Kf was less than 0.08 ml . sec-1 . mm Hg-1 . 1.73 m-2 in azotemic, but exceeded this value in nonazotemic patients. Although a selective reduction of Kf is predicted to lower the fractional clearance of dextrans, these were significant elevated in azotemic relative to nonazotemic patients (molecular radii 30 - 40 A). A theoretical analysis of the latter data suggests that over the foregoing range of FPD, a 15 to 30% decline in deltaP combined with a 30 to 0% reduction in Kf from values in nonazotemic patients best explains the experimental findings in azotemic patients.
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Williams RH, Thomas CE, Navar LG, Evan AP. Hemodynamic and single nephron function during the maintenance phase of ischemic acute renal failure in the dog. Kidney Int 1981; 19:503-15. [PMID: 7241885 DOI: 10.1038/ki.1981.48] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We studied ischemic acute renal failure in 28 dogs by micropuncture, microsphere, morphologic, and whole kidney hemodynamic techniques, 18 to 24 hours after the renal artery was clamped (clamping time, 60 to 90 min). Before the artery was clamped, renal blood flow (RBF) averaged 3.49 +/- (SEM) 0.23 ml/min x g and was not significantly different (3.70 +/- 0.34 ml/min x g) 18 hours after the ischemic episode. RBF autoregulatory capability was, however, significantly reduced. Fractional outer cortical blood flow decreased slightly from 41 +/- 2 to 36 +/- 3% (P less than 0.05) postischemia. Single nephron glomerular filtration rate (SNGFR) was highly variable from one animal to the next and ranged from 0 to 87 nl/min (mean, 36 +/- [SEM] 7 nl/min) in a manner similar to whole kidney inulin clearance, which ranged from 0 to 0.56 ml/min x g (mean, 0.30 +/- 0.05 ml+min x g). The correlation coefficient between SNGFR and inulin clearance was highly significant, indicating an association between SNGFR and whole kidney GFR. Proximal tubule pressure (PTP) averaged 20 +/- (SEM) 1 mm Hg. In 6 dogs, the glomerular filtration coefficient (Kf) was determined by measurements of stop-flow pressure, colloid osmotic pressure, SNGFR, PTP, and single nephron filtration fraction, Kf was below that obtained for control animals. Scanning electron microscopy (SEM) studies indicated that the endothelial fenestrations were reduced in number and size. These studies suggest that one major characteristic of ischemic nephropathy in the dog is a derangement in the filtration process. The maintenance of RBF in the postischemic phase may occur by utilization of the autoregulatory reserve of the renal vasculature.
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Parekh N, Veith U. Renal hemodynamics and oxygen consumption during postischemic acute renal failure in the rat. Kidney Int 1981; 19:306-16. [PMID: 7230617 DOI: 10.1038/ki.1981.21] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Acute renal failure in the rat was induced by occluding the left renal artery for 1 hour. The kidneys were examined 1, 3, 10, and 40 days after temporary ischemia. Inulin clearance was essentially zero in oligoanuric kidneys on days 1 and 3, and regained 14% and 63% of the control value on days 10 and 40, respectively. Mean cortical blood flow remained almost constant at 75% of control up to day 10 and normalized subsequently on day 40. Renal oxygen consumption during anuria on days 1 and 3 was 53% and 46% of the control value and increased thereafter concurrently with the restoration of renal function. With a single linear correlation being assumed to exist between sodium reabsorption and oxygen consumption for all kidneys, the sodium reabsorption and oxygen consumption for all kidneys, the sodium transport estimated from oxygen consumption on day 1 was about 40% of control value. The difference between the sodium transport calculated from oxygen consumption and that from inulin clearance decreased with time in the recovery phase. The results indicate only a partial reduction of GFR due to the reduced blood flow in this model. The data are consistent with the hypothesis that tubular leakage and tubular obstruction play an important role in the loss of renal function during the manifestation of acute renal failure.
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Myers BD, Carrie BJ, Yee RR, Hilberman M, Michaels AS. Pathophysiology of hemodynamically mediated acute renal failure in man. Kidney Int 1980; 18:495-504. [PMID: 6164815 DOI: 10.1038/ki.1980.163] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A tubular injury characterized by intraluminal obstruction and transtubular backleak of glomerular filtrate occurs in experimental acute renal failure (ARF) in animals. To determine whether these alterations also occur in human ARF, we studied 44 patients developing nonoliguric ARF following cardiac surgery. The delay in appearance of i.v. administered inulin in urine (Tu) was used as a measure of tubular fluid flow rate. Tu was not longer in 13 ARF patients than it was in control subjects (7.2 vs 9.0 min), suggesting that at least a subpopulation of tubules was widely patent. The fractional urinary dextran clearance profile (thetaD; radii, 20 to 40 A) was then determined in 20 patients with sustained ARF in whom inulin clearance averaged 11 +/- 1 ml/min/1.73 m2. A mass conservation model, which assumes that thetaD in Bowman's space in ARF is the same as that measured in controls, when applied to the experimental observations revealed that, on the average, 42% of filtered inulin was lost by transtubular backleak. A similar fractional inulin backleak (38%) persisted in 11 additional patients in whom ARF had begun to recover and in whom inulin clearance averaged 26 +/- 3 ml/min/1.73 m2. These findings suggest that in hemodynamically-mediated and nonoliguric ARF, (1) tubular obstruction is not homogeneous, and (2) backleak of glomerular filtrate contributes to but does not fully account for depression of inulin clearance.
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35
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Müller-Suur R, Norlén BJ, Persson AE. Resetting of tubuloglomerular feedback in rat kidneys after unilateral nephrectomy. Kidney Int 1980; 18:48-57. [PMID: 7012420 DOI: 10.1038/ki.1980.109] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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36
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Kramer HJ, Schüürmann J, Wassermann C, Düsing R. Prostaglandin-independent protection by furosemide from oliguric ischemic renal failure in conscious rats. Kidney Int 1980; 17:455-64. [PMID: 7392420 DOI: 10.1038/ki.1980.53] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In 38 conscious rats divided into seven groups, acute unilateral ischemic renal failure was induced by 1 hour of complete occlusion of the left renal artery while the contralateral kidney remained intact. Renal excretory function of the left kidney was monitored up to 144 hours after ischemia and revealed a typical course of oliguric renal failure with oligoanuria persisting for more than 48 hours. Urinary osmolality and sodium concentration became plasma isotonic after release of renal artery occlusion and approximated control values on day 6 after ischemia. In nine rats, the i.v. infusion of furosemide before (6 microgram/min/100 g body wt) and after (12 microgram/min/100 g body wt) renal artery occlusion protected the ischemic kidney from oligoanuria with endogenous creatinine clearance of 0.42 +/- 0.11 ml/min/g kidney wt 5 hours after ischemia. Tubular absorption of sodium and water was at least partially preserved 36 hours after ischemia when infusion of furosemide was stopped. The loop diuretic significantly (P less than 0.01) increased total urinary prostaglandin (PG) E2 excretion before and after renal artery occlusion; and 5 hours after ischemia, PGE2 excretion from the ischemic kidney significantly exceeded that from the intact kidney (P less than 0.05). Indomethacin (1 mg/100 g body wt) administered in six animals markedly suppressed control PGE2 excretion (P less than 0.05) as well as the furosemide-induced rise in urinary PG excretion before and after ischemia but did not modify the protective effect of the diuretic in this experimental model. Inhibition of PG synthesis, however, reduced urinary flow rate and sodium and potassium excretion of the contralateral intact kidney and almost completely prevented its compensatory rise in creatinine clearance. The results indicate that mechanisms other than the intrarenal prostaglandin system must be considered to mediate the protective effects of furosemide in acute ischemic renal failure.
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38
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Abstract
To define the pattern of recovery from postischemic acute renal failure (ARF), we performed clearance and micropuncture studies at intervals of 1, 2, 4, and 8 weeks following 60 min of complete unilateral renal artery occlusion in the rat. At 1 week, the inulin clearance (CIn) of the postischemic kidney was less than 2% of normal. The presence of marked preglomerular vasoconstriction was indicated by the reductions in renal blood flow (RBF), and stop-flow (SFP) and estimated glomerular capillary hydrostatic pressures (GCPe). In additon, there was evidence of tubular obstruction. Proximal intratubular pressures (PITP) were elevated, and intratubular casts could be seen in vivo and on histologic sections. At 2 weeks CIn had increased more than tenfold. This change occurred in the absence of any significant elevation in RBF, SFP, or GCPe. PITP had fallen, however, to normal values, and histologic sections revealed a marked reduction in the extent of intratubular casts. Ipsilateral urinary recovery of 3H-inulin microinjected into proximal convolutions was complete. At 4 and 8 weeks, there were further but more gradual rises in CIn, which were associated with progressive increases in RBF, SFP, and GCPe. These observations indicate that recovery from postischemic ARF occurred in a biphasic pattern. The initial rise in CIn was associated with the relief of intratubular obstruction, whereas subsequent rises in CIn occurred in association with progressive renal vasodilation.
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Frega NS, DiBona DR, Leaf A. The protection of renal function from ischemic injury in the rat. Pflugers Arch 1979; 381:159-64. [PMID: 574256 DOI: 10.1007/bf00582347] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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40
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41
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Steinhausen M, Thederan H, Nolinski D, Dallenbach FD, Schwaier A. Further evidence of tubular blockage after acute ischemic renal failure in Tupaia belangeri and rats. VIRCHOWS ARCHIV. A, PATHOLOGICAL ANATOMY AND HISTOLOGY 1978; 381:13-34. [PMID: 153643 DOI: 10.1007/bf00433482] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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42
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Norlén BJ, Engberg A, Källskog O, Wolgast M. Nephron function of the transplanted rat kidney. Kidney Int 1978; 14:10-20. [PMID: 355705 DOI: 10.1038/ki.1978.85] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tubular function in the early phase (one to three hours) after transplantation of rat kidneys was analyzed with respect to glomerular filtration, vascular and tubular pressures, and excretory variables. Kidneys exposed to a short period of cold ischemia (two hours) functioned almost normally, except for a polyuria. After 12 and 16 hr of cold ischemia, nephron heterogeneity appeared with 1) "normal" tubules, 2) dilated tubules, and 3) collapsed tubules. In the "normal" tubules, the pressure was increased to 20 mm Hg, and the filtration was reduced in proportion to the mean net driving force. The dilated tubules had no filtration due to a more or less complete tubular obstruction, probably located in the thin loop of Henle and in the collecting ducts. The collapsed tubules had no filtration due to glomerular ischemia, which in turn might be the consequence of afferent arteriolar constriction. The total GFR was greatly reduced since only the "normal" tubules contributed to the total filtration. Concentrating ability and potassium secretion were also impaired. We interpreted this impairment as being due to medullary dysfunction, which would explain the isosthenuria and the impaired potassium transport.
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43
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Donohoe JF, Venkatachalam MA, Bernard DB, Levinsky NG. Tubular leakage and obstruction after renal ischemia: structural-functional correlations. Kidney Int 1978; 13:208-22. [PMID: 651122 DOI: 10.1038/ki.1978.31] [Citation(s) in RCA: 230] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Mason J, Olbricht C, Takabatake T, Thurau K. The early phase of experimental acute renal failure. I. Intratubular pressure and obstruction. Pflugers Arch 1977; 370:155-63. [PMID: 562503 DOI: 10.1007/bf00581689] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Tubular obstruction in acute renal failure, postulated to cause the restricted excretory function, is suggested by raising intratubular pressure, to lower effective filtration pressure and diminish urine output. To examine the applicability of the obstruction hypothesis to the pathogenesis of experimental acute renal failure, proximal intratubular pressure and renal function were measured after renal insults of different origins and severity. Obstruction in acute renal failure kidneys should manifest itself as an increase in intratubular pressure for a least 12 h, for within this time period following ureteral occlusion, elevated pressures were found to reflect obstruction. The consistent existence of raised proximal intratubular pressure in acute renal failure kidneys could not be detected; ischaemic and nephrototoxic models were found in which no rise in intratubular pressure could be demonstrated. The oliguric nature of acute renal failure kidneys could not be verified; ischaemic and nephrotoxic models were found in which urine output was either normal or enhanced. Only for methaemoglobin induced renal failure were raised intratubular pressure, oliguria and casts concurrent. It is concluded that obstruction is not a consistent feature of experimental acute renal failure and that the obstruction hypothesis may be specifically applicable to only a few models, which include haeme pigment and folic acid induced renal failure.
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Robinson JW, Mirkovitch V, Gomba S. Alterations in the dog renal tubular epithelium during normothermic ischemia. Kidney Int 1977; 11:86-92. [PMID: 846066 DOI: 10.1038/ki.1977.13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Dog kidneys were subjected to one, two, or three hours' normothermic ischemia in situ and were then excised for biochemical and histological evaluation. The uptake of para-aminohippurate (PAH) by cortical slices progressively decreased with prolongation of the ischemia, but active transport was never abolished. Glycine uptake and oxygen consumption were only reduced to a modest extent by the ischemia. The intracellular ion levels were drastically altered, with loss of potassium and gain of sodium and chloride, and considerable increases in tissue water were observed. Acid phosphatase was liberated by the whole organ into the venous blood and by the incubated slices into the incubation medium, but both biochemical and histochemical techniques showed that the total quantity of the enzyme in the cells was hardly changed. The histochemical reaction product was localized exclusively in the lysosomes. Morphological damage was slight after one or two hours' ischemia, but more pronounced after three hours, when some cells were seen to be detached from the basement membrane. These relatively minor changes seem insufficient to predict the ultimate fate of the organ after ischemia.
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Olbricht C, Mason J, Takabatake T, Hohlbrugger G, Thurau K. The early phase of experimental acute renal failure. II. tubular leakage and the reliability of glomerular markers. Pflugers Arch 1977; 372:251-8. [PMID: 564048 DOI: 10.1007/bf01063860] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Experiments were designed to determine whether leakage of substances across the tubular epithelium, which are impermeant in the normal kidney, falsifies the measurement of glomerular filtration rate in acute renal failure. Permeability to those substances most commonly used for filtration rate determination, polyfructosan, inulin and ferrocyanide, was estimated by measuring their recoveries following perfusion through various nephron segments in haeme pigment, ischaemic and nephrotoxic models of acute renal failure. Late proximal recovery of 14C ferrocyanide was only marginally decreased compared to controls, by a maximum of 6%. Distal recovery of polyfructosan, 14C and 3H inulin were depressed somewhat more, by a maximum of 11%. Urinary recovery of 14C inulin was reduced by only 15% in kidneys showing severely restricted renal function. It is concluded that tubular leakage is not a feature of significance in the early phase of moderate acute renal failure, that ferrocyanide and inulin are reliable markers for the determination of nephron filtration rate and water reabsorption, and that the reduction in whole kidney inulin or polyfructosan clearance reflects primarily a reduction in glomerular filtration rate.
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Steinhausen M, Müller P, Parekh N. Renal test dyes IV. Intravital Fluorescence microscopy and microphotometry of the tubularly secreted dye sulfonefluorescein. Pflugers Arch 1976; 364:83-9. [PMID: 986619 DOI: 10.1007/bf01062916] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The present study describes for the first time the use of the fluorescent dye sulfonefluorescein for intravital microscopy and microphotometry on the renal surface of rats. With help of this dye tubular secretion can be observed in mammalian kidney in vivo. Tubular secretion can further be quantified with microphotometrical measurements. The molecular structure of sulfonefluorescein is closely related to phenol red, which is known for its tubular secretion. Clearance experiments also show a secretion of sulfonefluorescein. The secretion can be inhibited by probenecid. Ureter ligation causes a strong increase in tubular concentration of the dye. After a temporary ischemia dye accumulation in tubular lumen is greatly reduced.
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49
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Whittembury G, Grantham JJ. Cellular aspects of renal sodium transport and cell volume regulation. Kidney Int 1976; 9:103-20. [PMID: 781381 DOI: 10.1038/ki.1976.15] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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50
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