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Sheikh-Hamad D, Nadkarni V, Choi YJ, Truong LD, Wideman C, Hodjati R, Gabbay KH. Cyclosporine A inhibits the adaptive responses to hypertonicity: a potential mechanism of nephrotoxicity. J Am Soc Nephrol 2001; 12:2732-2741. [PMID: 11729242 DOI: 10.1681/asn.v12122732] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Cell survival in the hypertonic environment of the renal medulla is dependent on the intracellular accumulation of protective organic solutes through the induction of genes whose transcriptional regulation is mediated in part by interaction between osmotic response elements and the transcription nuclear factor of activated T lymphocyte 5. It is shown that cyclosporine A (CsA) prevents the nuclear translocation of the transcription nuclear factor of activated T lymphocyte 5 and inhibits osmotic response element-mediated reporter gene expression. The expression of mRNA for hypertonicity-induced genes (aldose reductase, betaine/gamma-amino-n-butyric acid transporter 1, and heat shock protein 70) is also decreased in the medulla of CsA-treated rats. CsA inhibits the increase of betaine/gamma-amino-n-butyric acid transporter 1 and heat shock protein 70 mRNA in osmotically stressed MDCK cells, blocks cell proliferation under isotonic conditions, and augments hypertonicity-induced apoptosis. Histologic examination of the kidneys of CsA-treated rats shows a marked increase in apoptosis in the renal medulla where hypertonicity normally prevails. The data are consistent with calcineurin-mediated induction of hypertonic stress-response genes, and they suggest that CsA nephrotoxicity may in part result from inhibition of the adaptive responses to hypertonicity occurring during the urinary concentrating mechanism.
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Affiliation(s)
- David Sheikh-Hamad
- *Renal Section, Department of Medicine, Department of Pathology, and the Harry B. and Aileen Gordon Diabetes Research Laboratory, Molecular Diabetes and Metabolism Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Varsha Nadkarni
- *Renal Section, Department of Medicine, Department of Pathology, and the Harry B. and Aileen Gordon Diabetes Research Laboratory, Molecular Diabetes and Metabolism Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Yeong-Jin Choi
- *Renal Section, Department of Medicine, Department of Pathology, and the Harry B. and Aileen Gordon Diabetes Research Laboratory, Molecular Diabetes and Metabolism Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Luan D Truong
- *Renal Section, Department of Medicine, Department of Pathology, and the Harry B. and Aileen Gordon Diabetes Research Laboratory, Molecular Diabetes and Metabolism Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Christi Wideman
- *Renal Section, Department of Medicine, Department of Pathology, and the Harry B. and Aileen Gordon Diabetes Research Laboratory, Molecular Diabetes and Metabolism Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Ramin Hodjati
- *Renal Section, Department of Medicine, Department of Pathology, and the Harry B. and Aileen Gordon Diabetes Research Laboratory, Molecular Diabetes and Metabolism Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Kenneth H Gabbay
- *Renal Section, Department of Medicine, Department of Pathology, and the Harry B. and Aileen Gordon Diabetes Research Laboratory, Molecular Diabetes and Metabolism Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
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Navar LG, Mitchell KD, Harrison-Bernard LM, Kobori H, Nishiyama A. Review: Intrarenal angiotensin II levels in normal and hypertensive states. J Renin Angiotensin Aldosterone Syst 2001; 2:S176-S184. [PMID: 19644566 PMCID: PMC2717721 DOI: 10.1177/14703203010020013001] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- L Gabriel Navar
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue New Orleans, LA 70112 USA,
| | - Kenneth D Mitchell
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue New Orleans, LA 70112 USA
| | - Lisa M Harrison-Bernard
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue New Orleans, LA 70112 USA
| | - Hiroyuki Kobori
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue New Orleans, LA 70112 USA
| | - Akira Nishiyama
- Department of Physiology, Tulane University School of Medicine, 1430 Tulane Avenue New Orleans, LA 70112 USA
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Wang CT, Chin SY, Navar LG. Impairment of pressure-natriuresis and renal autoregulation in ANG II-infused hypertensive rats. Am J Physiol Renal Physiol 2000; 279:F319-25. [PMID: 10919852 DOI: 10.1152/ajprenal.2000.279.2.f319] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic infusions of initially subpressor doses of angiotensin II (ANG II) lead to progressive hypertension over a 2-wk period and to augmented intrarenal ANG II levels. The present study was performed to investigate total renal blood flow (RBF) and medullary blood flow (MBF) autoregulatory behavior and pressure-natriuresis in ANG II-infused hypertensive rats and how these are modified by concomitant treatment with an ANG II AT(1) receptor antagonist. ANG II-infused rats (n = 27) were prepared by administration of ANG II at 60 ng/min via osmotic minipump for 13 days. Twelve of the ANG II-infused hypertensive rats were treated with losartan in the drinking water (30 mg. kg.(-1) day(-1)). Rats were anesthetized with pentobarbital sodium (50 mg/kg, ip) and prepared for renal function measurements. An aortic clamp was placed above the junction of the left renal artery to reduce renal arterial pressure. Autoregulatory responses for renal plasma flow, overall RBF, and glomerular filtration rate were impaired in ANG II-infused hypertensive rats; however, MBF autoregulation was not disrupted. Most strikingly, pressure-natriuresis was markedly suppressed in ANG II-infused hypertensive rats. Chronic treatment with losartan prevented the impairment of the pressure-natriuresis relationship caused by chronic ANG II infusion. These findings demonstrate that chronic ANG II infusion leads to marked impairment of sodium excretion and suppression of the pressure-natriuresis relationship, which may contribute to the progressive hypertension that occurs in this model. These renal effects are prevented by simultaneous treatment with an AT(1) receptor blocker.
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Affiliation(s)
- C T Wang
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112, USA
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