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Cooper TK, Meyerholz DK, Beck AP, Delaney MA, Piersigilli A, Southard TL, Brayton CF. Research-Relevant Conditions and Pathology of Laboratory Mice, Rats, Gerbils, Guinea Pigs, Hamsters, Naked Mole Rats, and Rabbits. ILAR J 2022; 62:77-132. [PMID: 34979559 DOI: 10.1093/ilar/ilab022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/12/2021] [Indexed: 12/31/2022] Open
Abstract
Animals are valuable resources in biomedical research in investigations of biological processes, disease pathogenesis, therapeutic interventions, safety, toxicity, and carcinogenicity. Interpretation of data from animals requires knowledge not only of the processes or diseases (pathophysiology) under study but also recognition of spontaneous conditions and background lesions (pathology) that can influence or confound the study results. Species, strain/stock, sex, age, anatomy, physiology, spontaneous diseases (noninfectious and infectious), and neoplasia impact experimental results and interpretation as well as animal welfare. This review and the references selected aim to provide a pathology resource for researchers, pathologists, and veterinary personnel who strive to achieve research rigor and validity and must understand the spectrum of "normal" and expected conditions to accurately identify research-relevant experimental phenotypes as well as unusual illness, pathology, or other conditions that can compromise studies involving laboratory mice, rats, gerbils, guinea pigs, hamsters, naked mole rats, and rabbits.
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Affiliation(s)
- Timothy K Cooper
- Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA
| | - David K Meyerholz
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Amanda P Beck
- Department of Pathology, Yeshiva University Albert Einstein College of Medicine, Bronx, New York, USA
| | - Martha A Delaney
- Zoological Pathology Program, University of Illinois at Urbana-Champaign College of Veterinary Medicine, Urbana-Champaign, Illinois, USA
| | - Alessandra Piersigilli
- Laboratory of Comparative Pathology and the Genetically Modified Animal Phenotyping Service, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Teresa L Southard
- Department of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA
| | - Cory F Brayton
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Leader CJ, Wilkins GT, Walker RJ. The effect of spironolactone on cardiac and renal fibrosis following myocardial infarction in established hypertension in the transgenic Cyp1a1Ren2 rat. PLoS One 2021; 16:e0260554. [PMID: 34843581 PMCID: PMC8629264 DOI: 10.1371/journal.pone.0260554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/11/2021] [Indexed: 11/19/2022] Open
Abstract
AIMS The renin-angiotensin-aldosterone axis plays a key role in mediating cardiac and kidney injury. Mineralocorticoid receptor antagonism has beneficial effects on cardiac dysfunction, but effects are less well quantified in the cardiorenal syndrome. This study investigated cardiac and kidney pathophysiology following permanent surgical ligation to induce myocardial infarction (MI) in hypertensive animals with or without mineralocorticoid receptor antagonism. METHODS Hypertension was induced in adult male Cyp1a1Ren2 rats. Hypertensive animals underwent MI surgery (n = 6), and were then treated daily with spironolactone for 28 days with serial systolic blood pressure measurements, echocardiograms and collection of urine and serum biochemical data. They were compared to hypertensive animals (n = 4), hypertensive animals treated with spironolactone (n = 4), and hypertensive plus MI without spironolactone (n = 6). Cardiac and kidney tissue was examined for histological and immunohistochemical analysis. RESULTS MI superimposed on hypertension resulted in an increase in interstitial cardiac fibrosis (p<0.001), renal cortical interstitial fibrosis (p<0.01) and glomerulosclerosis (p<0.01). Increased fibrosis was accompanied by myofibroblast and macrophage infiltration in the heart and the kidney. Spironolactone post-MI, diminished the progressive fibrosis (p<0.001) and inflammation (myofibroblasts (p<0.05); macrophages (p<0.01)) in both the heart and the kidney, despite persistently elevated SBP (182±19 mmHg). Despite the reduction in inflammation and fibrosis, spironolactone did not modify ejection fraction, proteinuria, or renal function when compared to untreated animals post MI. CONCLUSION This model of progressive cardiorenal dysfunction more closely replicates the clinical setting. Mineralocorticoid receptor blockade at a clinically relevant dose, blunted progression of cardiac and kidney fibrosis with reduction in cardiac and kidney inflammatory myofibroblast and macrophage infiltration. Further studies are underway to investigate the combined actions of angiotensin blockade with mineralocorticoid receptor blockade.
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Affiliation(s)
- C. J. Leader
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - G. T. Wilkins
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - R. J. Walker
- Department of Medicine, University of Otago, Dunedin, New Zealand
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Carlson T, Yee L. Spontaneous Necrotizing Hepatic Arteriopathy in Male Sprague-Dawley Rats. Toxicol Pathol 2020; 48:905-908. [PMID: 32975497 DOI: 10.1177/0192623320960724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Differentiating test article-related vascular changes from spontaneous findings is important for microscopic interpretation in drug safety evaluation studies intended for regulatory submission. Here, we report background spontaneous hepatic artery degeneration and necrosis in up to 20% of 3- to 9-month-old control male Sprague-Dawley rats in 23 individual safety studies. The vascular degeneration occurred in one cross section of a medium-sized hepatic artery near the hilus and ranged from acute intramural hemorrhage and fibrinoid necrosis to chronic fibrosis of the vascular wall with perivascular edema, hemorrhage, and inflammatory cell infiltrates. The cause was uncertain. Many microscopic features were consistent with systemic necrotizing arteriopathy (SNA) or polyarteritis; however, there was no change in arteries commonly affected in SNA/polyarteritis (mesenteric, pancreatic, or testicular arteries) and hepatic artery degeneration/necrosis occurred in younger rats which is unusual for SNA/polyarteritis. Spontaneous hepatic artery degeneration/necrosis represents a sporadic background finding that may be confused with a test article's toxicologic effect.
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Affiliation(s)
- Tracy Carlson
- 537465Charles River Laboratories Inc, Mattawan, MI, USA
| | - Lily Yee
- 537465University of Michigan, Ann Arbor, MI, USA
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Adams DF, Watkins MS, Durette L, Laliberté J, Goulet F, Debien E, Frazier KS, Mellal N, Chen L, Shi W, Thomas R, Hu E. Carcinogenicity Assessment of Daprodustat (GSK1278863), a Hypoxia-Inducible Factor (HIF)-Prolyl Hydroxylase Inhibitor. Toxicol Pathol 2019; 48:362-378. [PMID: 31640478 DOI: 10.1177/0192623319880445] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Daprodustat (GSK1278863) is a hypoxia-inducible factor (HIF)-prolyl hydroxylase (PHD) inhibitor in development for treatment of anemia of chronic kidney disease. Daprodustat's biological activity simulates components of the natural response to hypoxia; inhibition of PHDs results in HIF stabilization and modulation of HIF-controlled gene products, including erythropoietin. The carcinogenic potential of daprodustat was evaluated in 2-year carcinogenicity studies in Sprague-Dawley rats and CD-1 mice, where once-daily doses were administered. The mouse study also included evaluation of daprodustat's 3 major circulating human metabolites. There were no neoplastic findings that were considered treatment related in either study. Exaggerated pharmacology resulted in significantly increased red cell mass and subsequent multiorgan congestion and secondary non-neoplastic effects in both species, similar to those observed in chronic toxicity studies. In rats, these included aortic thrombosis and an exacerbation of spontaneous rodent cardiomyopathy, which contributed to a statistically significant decrease in survival in high-dose males (group terminated in week 94). Survival was not impacted in mice at any dose. Systemic exposures (area under the plasma concentration-time curve) to daprodustat at the high doses in rats and mice exceed predicted maximal human clinical exposure by ≥143-fold. These results suggest that daprodustat and metabolites do not pose a carcinogenic risk at clinical doses.
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Affiliation(s)
| | | | - Luc Durette
- Charles River Laboratories, Sherbrooke, Quebec, Canada
| | | | - Félix Goulet
- Charles River Laboratories, Senneville, Quebec, Canada
| | - Elaine Debien
- Charles River Laboratories, Sherbrooke, Quebec, Canada
| | | | - Nacéra Mellal
- Charles River Laboratories, Senneville, Quebec, Canada
| | | | - Wei Shi
- GlaxoSmithKline R&D, Collegeville, PA, USA
| | | | - Erding Hu
- GlaxoSmithKline R&D, Collegeville, PA, USA
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Leader CJ, Moharram M, Coffey S, Sammut IA, Wilkins GW, Walker RJ. Myocardial global longitudinal strain: An early indicator of cardiac interstitial fibrosis modified by spironolactone, in a unique hypertensive rat model. PLoS One 2019; 14:e0220837. [PMID: 31404095 PMCID: PMC6690508 DOI: 10.1371/journal.pone.0220837] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 07/25/2019] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVES Is global longitudinal strain (GLS) a more accurate non-invasive measure of histological myocardial fibrosis than left ventricular ejection fraction (LVEF) in a hypertensive rodent model. BACKGROUND Hypertension results in left ventricular hypertrophy and cardiac dysfunction. Speckle-tracking echocardiography has emerged as a robust technique to evaluate cardiac function in humans compared with standard echocardiography. However, its use in animal studies is less clearly defined. METHODS Cyp1a1Ren2 transgenic rats were randomly assigned to three groups; normotensive, untreated hypertensive or hypertensive with daily administration of spironolactone (human equivalent dose of 50 mg/day). Cardiac function and interstitial fibrosis development were monitored for three months. RESULTS The lower limit of normal LVEF was calculated to be 75%. After three months hypertensive animals (196±21 mmHg systolic blood pressure (SBP)) showed increased cardiac fibrosis (8.8±3.2% compared with 2.4±0.7% % in normals), reduced LVEF (from 81±2% to 67±7%) and impaired myocardial GLS (from -17±2% to -11±2) (all p<0.001). Myocardial GLS demonstrated a stronger correlation with cardiac interstitial fibrosis (r2 = 0.58, p<0.0001) than LVEF (r2 = 0.37, p<0.006). Spironolactone significantly blunted SBP elevation (184±15, p<0.01), slowed the progression of cardiac fibrosis (4.9±1.4%, p<0.001), reduced the decline in LVEF (72±4%, p<0.05) and the degree of impaired myocardial GLS (-13±1%, p<0.01) compared to hypertensive animals. CONCLUSIONS This study has demonstrated that, myocardial GLS is a more accurate non-invasive measure of histological myocardial fibrosis compared to standard echocardiography, in an animal model of both treated and untreated hypertension. Spironolactone blunted the progression of cardiac fibrosis and deterioration of myocardial GLS.
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Affiliation(s)
| | | | - Sean Coffey
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Ivan A. Sammut
- Department of Pharmacology, University of Otago, Dunedin, New Zealand
| | | | - Robert J. Walker
- Department of Medicine, University of Otago, Dunedin, New Zealand
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Obert LA, Frazier KS. Intrarenal Renin–Angiotensin System Involvement in the Pathogenesis of Chronic Progressive Nephropathy—Bridging the Informational Gap Between Disciplines. Toxicol Pathol 2019; 47:799-816. [DOI: 10.1177/0192623319861367] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chronic progressive nephropathy (CPN) is the most commonly encountered spontaneous background finding in laboratory rodents. Various theories on its pathogenesis have been proposed, but there is a paucity of data regarding specific mechanisms or physiologic pathways involved in early CPN development. The current CPN mechanism of action for tumorigenesis is largely based on its associated increase in tubular cell proliferation without regard to preceding subcellular degenerative changes. Combing through the published literature from multiple biology disciplines provided insight into the preceding cellular events. Mechanistic pathways involved in the progressive age-related decline in rodent kidney function and several key inflexion points have been identified. These critical pathway factors were then connected using data from renal models from multiple rodent strains, other species, and mechanistic work in humans to form a cohesive picture of pathways and protein interactions. Abundant data linked similar renal pathologies to local events involving hypoxia (hypoxia-inducible factor 1α), altered intrarenal renin–angiotensin system (RAS), oxidative stress (nitric oxide), and pro-inflammatory pathways (transforming growth factor β), with positive feedback loops and downstream effectors amplifying the injury and promoting scarring. Intrarenal RAS alterations seem to be central to all these events and may be critical to CPN development and progression.
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Leader CJ, Clark BJ, Hannah AR, Sammut IA, Wilkins GT, Walker RJ. Breeding Characteristics and Dose-dependent Blood Pressure Responses of Transgenic Cyp1a1-Ren2 Rats. Comp Med 2018; 68:360-366. [PMID: 30185285 DOI: 10.30802/aalas-cm-17-18000026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hypertension is a leading risk factor for cardiovascular and chronic kidney disease. A new rodent model (transgenic male Cyp1a1-Ren2 rats) provides reversible induction of hypertension through the addition of indole-3-carbinol (I3C) to the diet, without the need for surgical intervention, thus giving researchers control over both the onset of hypertension and its magnitude (I3C dose-dependency). We here report the breeding performance and productivity of Cyp1a1-Ren2 rats. Despite being transgenic, these animals proved to be efficient breeders. In addition to confirming inducible and reversible dose-dependent hypertension (by using I3C doses of 0.125%, 0.167%, and 0.25% [w/w] in the diet for 14 d, followed by normal chow for 4 d), we demonstrated that hypertension can be sustained chronically (14 wk) by continuous dosing with I3C (0.167% [w/w]) in the diet. In chronically dosed male rats, systolic blood pressure continued to rise, from 173 ± 11 mm Hg after 1 mo to 196 ± 19 mm Hg after 3 mo, with no adverse phenotypic features observed. In conclusion, Cyp1a1-Ren2 rats are a useful animal model to investigate hypertension-induced end-organ damage and potential new therapeutic targets to manage hypertension.
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Affiliation(s)
| | - Barbara J Clark
- Hercus-Taieri Resource Unit, University of Otago, Dunedin, New Zealand
| | - Amber R Hannah
- Hercus-Taieri Resource Unit, University of Otago, Dunedin, New Zealand
| | - Ivan A Sammut
- Department of Pharmacology, University of Otago, Dunedin, New Zealand
| | - Gerard T Wilkins
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Robert J Walker
- Department of Medicine, University of Otago, Dunedin, New Zealand
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Ohta R, Kumagai F, Marumo H, Usumi K, Saito Y, Kuwagata M. Stress-reactive rats (high-avoidance female rats) have a shorter lifespan than stress-nonreactive rats (low-avoidance female rats). J Toxicol Pathol 2015; 29:77-84. [PMID: 27182111 PMCID: PMC4866005 DOI: 10.1293/tox.2015-0045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 11/02/2015] [Indexed: 11/19/2022] Open
Abstract
Although Hatano high-avoidance and low-avoidance rats (HAA and LAA, respectively) have been selectively bred for good versus poor avoidance learning, HAA rats are known to be more reactive to stress than LAA rats. In this study, HAA and LAA female rats were compared during reproductive aging by observing estrous cycles from 8 to 11 months of age. Furthermore, these rats were allowed to live out their natural lifespans, that is, until 24 months of age, in order to compare their survival and to clarify the relationship between reproductive aging and tumor development. At eight months of age, 2 of 35 HAA rats and 20 of 35 LAA rats had abnormal estrous cycles. The median lifespan of the HAA rats (673 days) was shorter than that of the LAA rats (733 days). The incidence of pituitary neoplasia was higher in the HAA rats than in the LAA rats. These results suggest that HAA female rats (i.e., stress-reactive rats) have a shorter lifespan than LAA female rats (i.e., stress-nonreactive rats) and develop pituitary neoplasia, which was one of the causal factors in their accelerated mortality. However, the onset of an age-matched abnormal cycle did not correspond with their lifespan.
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Affiliation(s)
- Ryo Ohta
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Fumiaki Kumagai
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Hideki Marumo
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Kenji Usumi
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Yoshiaki Saito
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
| | - Makiko Kuwagata
- Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan
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Kunert-Keil C, Landsberger M, Jantzen F, Niessner F, Kroemer HK, Felix SB, Brinkmeier H, Peters J. Molecular changes in the early phase of renin-dependent cardiac hypertrophy in hypertensive cyp1a1ren-2 transgenic rats. J Renin Angiotensin Aldosterone Syst 2012; 14:41-50. [PMID: 23060473 DOI: 10.1177/1470320312460070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
An early response to high arterial pressure is the development of cardiac hypertrophy. Functional and transcriptional regulation of ion channels and Ca(2+) handling proteins are involved in this process but the relative contribution of each is unclear. In this study, we investigated the expression of genes involved in action potential generation and Ca(2+) homeostasis of cardiomyocytes in hypertensive cyp1a1ren-2 transgenic rats. In this model, the transgene prorenin was induced by indole-3-carbinol for 2 weeks allowing the induction of hypertension. Electrophysiological recordings from cardiomyocytes of hypertensive rats revealed a slight increase in membrane capacitance consistent with cellular hypertrophy. L-type calcium current density was reduced by 30%. Left ventricles of hypertensive rats showed a significant increase in transcript and protein levels of the cation channel TRPC6 and FK506-binding protein, whereas levels of SERCA2 and voltage-dependent potassium channels K(v)4.2 and K(v)4.3 were found to be decreased. Further, a marked nuclear localization of the transcription factors GATA4 and NFATC4 was observed in cardiac tissue of hypertensive rats. The cyp1a1ren-2 transgenic rat thus appears to be a valid model to investigate early changes in cardiac hypertrophy. This study points to roles for TRPC6, FK506BP, SERCA2, K(v)4.2, and K(v)4.3 in the development of cardiac hypertrophy.
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Peters BS, Dornaika R, Hosten N, Hadlich S, Mullins JJ, Peters J, Rettig R. Regression of cardiac hypertrophy in cyp1a1ren-2 transgenic rats. J Magn Reson Imaging 2012; 36:373-8. [PMID: 22517449 DOI: 10.1002/jmri.23661] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 03/07/2012] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To evaluate the usefulness of the cyp1a1ren-2 transgenic rat model of inducible hypertension for studies of the development and regression of cardiac hypertrophy. MATERIALS AND METHODS Cyp1a1ren-2 rats received a diet containing 0% or 0.167% indole-3-carbinonl (I3C) for 4 weeks to induce hypertension. Cardiac magnetic resonance imaging (MRI) at 7 T was performed every second week for 10 weeks to measure left ventricular mass and the ejection fraction. Concomitantly, in six cyp1a1ren-2 rats blood pressure was recorded telemetrically. RESULTS Plasma prorenin concentrations rose from 138 ± 38 to 15,490 ± 3990 ng/angiotensin I/mL/h (P < 0.001) in I3C-treated transgenic rats and returned to basal levels after cessation of I3C. Mean blood pressure increased to a plateau of 169 ± 11 mmHg by the second week of induction. After cessation of I3C (day 28), arterial pressure dropped to values slightly below those prior to induction within 4 days (basal: 106 ± 7 mmHg, day 32: 103 ± 21 mmHg; NS). At day 28, left ventricular mass was increased by 39% vs. 4% in controls (P < 0.001) without changes of the ejection fraction. Cardiac hypertrophy was completely reversed at day 70, as evaluated by MRI. CONCLUSION The cyp1a1ren-2 transgenic rat is a useful model to study reversal and healing in the absence of surgical interventions.
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Affiliation(s)
- Barbara S Peters
- Department of Cardiovascular Medicine, Institute of Physiology, University of Greifswald, Karlsburg, Germany.
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Peters J, Schlüter T, Riegel T, Peters BS, Beineke A, Maschke U, Hosten N, Mullins JJ, Rettig R. Lack of cardiac fibrosis in a new model of high prorenin hyperaldosteronism. Am J Physiol Heart Circ Physiol 2009; 297:H1845-52. [PMID: 19749160 PMCID: PMC2781377 DOI: 10.1152/ajpheart.01135.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to test the hypothesis that elevation of prorenin in plasma is sufficient to induce cardiac fibrosis. Normotensive cyp1a1ren-2 transgenic rats with normal plasma prorenin and aldosterone levels were given 0.125% indole-3-carbinol (I3C) orally for a period of 12 wk. Plasma prorenin and aldosterone levels were determined in 4-wk intervals, and cardiac marker enzymes for hypertrophy, fibrosis, and oxidative stress as well as cardiac pathology were investigated. In I3C-treated cyp1a1 ren-2 transgenic rats, plasma prorenin concentrations were >100-fold elevated (> or = 7.1 + or - 2.6 microg ANG I.ml(-1).h(-1) vs. < or = 0.07 + or - 0.1; P < 0.001), whereas active renin levels were suppressed (0.09 + or - 0.02 vs. 0.2 + or - 0.1; P < 0.05). Aldosterone concentrations were elevated three- to fourfold for a period of >4 wk (574 + or - 51 vs. 160 + or - 68 pg/ml; P < 0.01). After 12 wk of I3C, rats exhibited moderate cardiac hypertrophy (heart weight/body weight 2.5 + or - 0.04 vs. 3.1 + or - 0.1 mg/g; P < 0.01). There was a slight increase in mRNA contents of endothelin 1 (1.21 + or - 0.08 vs. 0.75 + or - 0.007; P < 0.001), NADP oxidase-2 (1.03 + or - 0.006 vs. 0.76 + or - 0.04; P < 0.001), transforming growth factor-beta (0.99 + or - 0.06 vs. 0.84 + or - 0.04; P < 0.05), collagen type I (1.32 + or - 0.32 vs. 0.94 + or - 0.18; P < 0.05), and intercellular adhesion molecule-1 (1.12 + or - 0.12 vs. 0.84 + or - 0.08; P < 0.05). These genes are known to be stimulated by the renin-angiotensin system. There were no histological signs of fibrosis in the heart. We found that prorenin and aldosterone alone are not sufficient to induce considerable cardiac fibrosis in the absence of sodium load.
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Affiliation(s)
- Jörg Peters
- Institute of Physiology, Univ. of Greifswald, Greifswalder Str. 11C, D-17495 Karlsburg, Germany.
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