151
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Nishio Y, Sato Y, Taniguchi R, Shizuta S, Doi T, Morimoto T, Kimura T, Kita T. Cardiac Troponin T vs Other Biochemical Markers in Patients With Congestive Heart Failure. Circ J 2007; 71:631-5. [PMID: 17456983 DOI: 10.1253/circj.71.631] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Several pathologic processes can cause myocardial injury, which is followed by cardiac remodeling and congestive heart failure (CHF). Cardiac troponin T (cTnT), a specific and sensitive marker of myocardial injury, has been related to long-term outcome in patients with CHF, so the relationship between cTnT and other biochemical markers associated with the pathophysiology of CHF was investigated in the present study. METHODS AND RESULTS Between February 2004 and December 2005, 145 consecutive hospitalized patients (mean left ventricular ejection fraction (LVEF) 31.6+/-0.9%) with CHF were divided into low (<0.01 ng/ml) and high (> or =0.01 ng/ml) serum cTnT groups. Correlations with other prognostic biochemical markers, including brain natriuretic peptide (BNP), type I collagen C-terminal telopeptide (ICTP), procollagen type III peptide (PIIIP), renin, norepinephrine (NOREPI), C-reactive protein (CRP), cholesterol, hemoglobin (Hb), uric acid and HbA1c were examined. cTnT was high in 46 (32%) and low in 99 (68%) patients at baseline. Patients with high cTnT had abnormally high blood concentrations of BNP (p<0.0001), ICTP (p<0.0001), PIIIP (p=0.0006), NOREPI (p=0.0119), CRP (p=0.0003), uric acid (p=0.0026) and HbA1c (p=0.0361). In contrast, concentrations of cholesterol and Hb were significantly lower in patients with high cTnT (p=0.0319 and 0.0005, respectively). Death from or rehospitalization for CHF occurred in 41% in the high vs 9% in the low cTnT group (p=0.0002). Univariate analysis showed that high cTnT (p=0.0005), BNP (p=0.0001), renin (p=0.0158), NOREPI (p=0.0094), old age (p=0.0390), low LVEF (p=0.0231) and high New York Heart Association (NYHA) class (p=0.0006) were predictors of death from or rehospitalization for CHF. By multivariate analysis including BNP, NOREPI, age, LVEF and NYHA class, high cTnT and renin remained as significant predictors. CONCLUSIONS Patients with ongoing myocardial injury and high cTnT had associated findings consistent with activation of the sympathetic system, synthesis of cardiac fibrosis, inflammation and metabolic abnormalities. By multivariate analysis, high cTnT and renin remained significant predictors of death or rehospitalization.
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Affiliation(s)
- Yukiko Nishio
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
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152
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Cano-Martínez A, Vargas-González A, Guarner-Lans V. Temperature effect on contractile activity of the Ambystoma dumerilii heart previously treated with isoproterenol. Comp Biochem Physiol A Mol Integr Physiol 2006; 147:743-749. [PMID: 17196415 DOI: 10.1016/j.cbpa.2006.10.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 10/20/2006] [Accepted: 10/22/2006] [Indexed: 10/24/2022]
Abstract
The spontaneous heart rate (HR) and ventricular (V) and atrium (A) tensions (T) were evaluated through isolated organ assays at different temperatures in hearts from Ambystoma dumerilii control and treated with isoproterenol (ISO) [(150 mg/kg i.p. each 24 h, for 3 days)] on days 1, 5, 30 and 90 after ISO. In control hearts, the HR increased and the T decreased when temperature was augmented. One day after ISO the HR (43-24%) and T (50-25%) decreased with respect to control, between 8 and 24 degrees C. Five, 30 and 90 days after ISO, HR showed a gradual recovery with similar effect when the temperature was changed; but the AT increased and VT decreased at temperatures between 8 and 12 degrees C and were only recovered at temperatures above 12 degrees C. Our results indicate that the HR recovers after ISO in A. dumerilii independently of temperature. The recovery of AT and VT is similar to HR at temperatures higher than 12 degrees C and the increases in VT could be compensating the decrease in VT caused by ISO, at temperatures lower than 12 degrees C. The changes in heart contractile activity of A. dumerilii after insult show the thermic plasticity that is observed in ectothermic vertebrates.
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Affiliation(s)
- A Cano-Martínez
- Departamento de Fisiología, Instituto Nacional de Cardiología "Ignacio Chávez", Juan Badiano # 1, Colonia Sección XVI, Tlalpan, México D.F. 14080, Mexico.
| | - A Vargas-González
- Departamento de Fisiología, Instituto Nacional de Cardiología "Ignacio Chávez", Juan Badiano # 1, Colonia Sección XVI, Tlalpan, México D.F. 14080, Mexico
| | - V Guarner-Lans
- Departamento de Fisiología, Instituto Nacional de Cardiología "Ignacio Chávez", Juan Badiano # 1, Colonia Sección XVI, Tlalpan, México D.F. 14080, Mexico
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153
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Abstract
Cardiac function is determined by the dynamic interaction of various cell types and the extracellular matrix that composes the heart. This interaction varies with the stage of development and the degree and duration of mechanical, chemical, and electrical signals between the various cell types and the ECM. Understanding how these complex signals interact at the molecular, cellular, and organ levels is critical to understanding the function of the heart under a variety of physiological and pathophysiological conditions. Quantitative approaches, both in vivo and in vitro, are essential to understand the dynamic interaction of mechanical, chemical, and electrical stimuli that govern cardiac function. The fibroblast can thus be a friend in normal function or a foe in pathophysiological conditions.
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Affiliation(s)
- Troy A Baudino
- Department of Cell and Developmental Biology and Anatomy, School of Medicine, University of South Carolina, Columbia, SC 29208, USA
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154
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Burniston JG, Clark WA, Tan LB, Goldspink DF. Dose-dependent separation of the hypertrophic and myotoxic effects of the beta(2)-adrenergic receptor agonist clenbuterol in rat striated muscles. Muscle Nerve 2006; 33:655-63. [PMID: 16411205 PMCID: PMC1828609 DOI: 10.1002/mus.20504] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Muscle growth in response to large doses (milligrams per kilogram) of beta(2)-adrenergic receptor agonists has been reported consistently. However, such doses may also induce myocyte death in the heart and skeletal muscles and hence may not be safe doses for humans. We report the hypertrophic and myotoxic effects of different doses of clenbuterol. Rats were infused with clenbuterol (range, 1 microg to 1 mg.kg(-1)) for 14 days. Muscle protein content, myofiber cross-sectional area, and myocyte death were then investigated. Infusions of >or=10 microg.kg(-1).d(-1) of clenbuterol significantly (P<0.05) increased the protein content of the heart (12%-15%), soleus (12%), plantaris (18%-29%), and tibialis anterior (11%-22%) muscles, with concomitant myofiber hypertrophy. Larger doses (100 microg or 1 mg) induced significant (P<0.05) myocyte death in the soleus (peak 0.2+/-0.1% apoptosis), diaphragm (peak 0.15+/-0.1% apoptosis), and plantaris (peak 0.3+/-0.05% necrosis), and significantly increased the area fraction of collagen in the myocardium. These data show that the low dose of 10 microg.kg(-1).d(-1) can be used in rats to investigate the anabolic effects of clenbuterol in the absence of myocyte death.
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Affiliation(s)
- Jatin G Burniston
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Webster Street, Liverpool L3 2ET, UK.
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155
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Davel APC, Kawamoto EM, Scavone C, Vassallo DV, Rossoni LV. Changes in vascular reactivity following administration of isoproterenol for 1 week: a role for endothelial modulation. Br J Pharmacol 2006; 148:629-39. [PMID: 16702995 PMCID: PMC1751879 DOI: 10.1038/sj.bjp.0706749] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. The aim of this study was to assess the effects of treatment with isoproterenol (ISO, 0.3 mg kg-1 day-1, s.c.) for 7 days on the vascular reactivity of rat-isolated aortic rings. Additionally, potential mechanisms underlying the changes that involved the endothelial modulation of contractility were investigated. 2. Treatment with ISO induced cardiac hypertrophy without changes in haemodynamic parameters. Aortic rings from ISO-treated rats showed an increase in the contraction response to phenylephrine (PHE) and serotonin, but did not change relaxations produced by acetylcholine or isoproterenol. Removal of the endothelium increased the responses to PHE in both groups. However, this procedure was less effective in ISO-treated as compared with control rats. Endothelial cell removal abolished the increase in the response to PHE in ISO-treated rats. The presence of Nomega-nitro-L-arginine methyl ester shifted the concentration-response curve to PHE to the left in both groups of rats. However, this effect was more pronounced in the ISO group. In addition, aminoguanidine (50 microM) potentiated the actions of PHE only in the ISO group. ISO treatment increased nitric oxide synthase (NOS) activity and neuronal NOS and endothelial NOS protein expression in the aorta. 3. Neither losartan (10 microM) nor indomethacin (10 microM) abolished the effects of ISO on the actions of PHE. Superoxide dismutase (SOD, 150 U ml-1) and L-arginine (5 mM), but neither catalase (300 U ml-1) nor apocynin (100 microM), blocked the effect of ISO treatment. In addition, we observed an increase in superoxide anion levels as measured by ethidium bromide fluorescence and of copper and zinc superoxide dismutase protein expression in ISO-treated rats. 4. In conclusion, our data suggest that ISO treatment alters the endothelial cell-mediated modulation of the contraction to PHE in rat aorta. The increased maximal response of PHE seems to be due to an increase in superoxide anion generation, which inactivates some of the basal NO produced and counteracts NO-mediated negative modulation even in the presence of high NO production and antioxidant defence.
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Affiliation(s)
- Ana Paula C Davel
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, ICB, University of São Paulo, Av. Professor Lineu Prestes, 1524, sala 101B, 05508-900 São Paulo, SP, Brazil
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Elisa Mitiko Kawamoto
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil
| | - Cristoforo Scavone
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil
| | - Dalton V Vassallo
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Luciana V Rossoni
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, ICB, University of São Paulo, Av. Professor Lineu Prestes, 1524, sala 101B, 05508-900 São Paulo, SP, Brazil
- Author for correspondence:
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156
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Ishizawa M, Mizushige K, Noma T, Namba T, Guo P, Murakami K, Tsuji T, Miyatake A, Ohmori K, Kohno M. An antioxidant treatment potentially protects myocardial energy metabolism by regulating uncoupling protein 2 expression in a chronic β-adrenergic stimulation rat model. Life Sci 2006; 78:2974-82. [PMID: 16580698 DOI: 10.1016/j.lfs.2006.02.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Revised: 11/16/2005] [Accepted: 02/27/2006] [Indexed: 11/15/2022]
Abstract
Excessive beta-adrenergic stimulation causes cardiac toxicity, which also contributes to cardiac oxidative stress. Although uncoupling protein 2 (UCP2), a member of the mitochondrial inner membrane carrier family, can regulate energy efficiency and oxidative stress in mitochondria, little data exist regarding interactions between UCP2 expression and beta-adrenergic stimulation induced cardiac oxidative damage. We investigated whether chronic beta-adrenergic stimulation induces myocardial energy metabolism abnormality via oxidative stress, including any role of UCP2. We also examined whether 3-methyl-1-phenyl-2-pyrazolin-5-one (MIC-186; edaravone), a potent free radical scavenger, has cardioprotective effects against beta-adrenergic stimulation. Male Sprague-Dawley rats received isoproterenol (1.2 mg/kg/day) subcutaneously or/and edaravone (30 mg/kg/day) orally. Isoproterenol increased the heart/body weight ratio, accompanied by an increase in the level of myocardial thiobarbituric acid reactive substances (TBARS) and a decreased phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio. Isoproterenol also markedly increased expressions of UCP2 mRNA (1.74 fold vs. non-isoproterenol) and protein (1.93 fold vs. non-isoproterenol). Edaravone had no apparent effect in hypertrophic responses, but significantly prevented both increases in TBARS and decreases in the PCr/ATP ratio. Edaravone also prevented increases in UCP2 mRNA (0.76 fold vs. isoproterenol) and protein (0.62 fold vs. isoproterenol) expressions against isoproterenol administration. Our results suggest that chronic beta-adrenergic stimulation induces myocardial energy inefficiency via excessive oxidative stress. The antioxidant effect of edaravone has potential to improve energy metabolism abnormalities against beta-adrenergic stimulation. Adequate regulation of UCP2 expression through artificial reduction of oxidative stress may play an important role in protection of the myocardial energy metabolism.
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Affiliation(s)
- Makoto Ishizawa
- Second Department of Internal Medicine, Kagawa University School of Medicine, Miki, Kita, Kagawa, 761-0793, Japan.
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157
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Osadchii OE, Woodiwiss AJ, Norton GR. Contractile responses to selective phosphodiesterase inhibitors following chronic beta-adrenoreceptor activation. Pflugers Arch 2005; 452:155-63. [PMID: 16369769 DOI: 10.1007/s00424-005-0025-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2005] [Accepted: 11/17/2005] [Indexed: 10/25/2022]
Abstract
Contractile responses to phosphodiesterase (PDE) inhibitors are attenuated in heart failure, an effect limiting the clinical value of these agents. In this study, we sought to determine whether abnormalities in the beta-adrenoreceptor (beta-AR)-cyclic adenosine monophosphate (cAMP) signal transduction are sufficient to account for downregulation of PDE inhibitor-induced inotropic responses following chronic sympathetic activation. Sustained beta-AR activation produced by administration of isoproterenol (ISO) (50 microg kg(-1) day(-1) i.p. for 1 month) to rats resulted in cardiac hypertrophy, but did not affect baseline cardiac systolic function, as assessed in vivo by echocardiography and ex vivo under controlled loading conditions and heart rate (left ventricular systolic pressure-volume and stress-strain relations). Moreover, chronic ISO administration did not alter the baseline myocardial norepinephrine release or inotropic responses to incremental concentrations of Ca(2+) in isolated, perfused heart preparations. However, left ventricular contractile responses to ISO, the PDE III inhibitor amrinone, and the PDE IV inhibitor rolipram were attenuated following chronic beta-AR activation. Myocardial cAMP concentrations after stimulation with amrinone and rolipram were similar in ISO-treated and control rats. However, in ISO-treated rats, a marked decrease in contractile responsiveness to the cell-permeable, PDE-resistant cAMP analogue, 8-bromoadenosine cAMP, was noted. In conclusion, these data suggest that in cardiac disease, sustained beta-AR activation, without producing ventricular systolic dysfunction or enhanced myocardial norepinephrine release, is sufficient to account for the downregulation of contractile responses to PDE inhibitors. This effect appears to be largely mediated through abnormalities in signal transduction between cAMP and Ca(2+)-induced Ca(2+) release.
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Affiliation(s)
- Oleg E Osadchii
- Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, University of the Witwatersrand Medical School, 7 York Road, Parktown 2193, Johannesburg, South Africa.
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158
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Miller DL, Li P, Dou C, Gordon D, Edwards CA, Armstrong WF. Influence of contrast agent dose and ultrasound exposure on cardiomyocyte injury induced by myocardial contrast echocardiography in rats. Radiology 2005; 237:137-43. [PMID: 16183929 DOI: 10.1148/radiol.2371041467] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To detect specific cardiomyocyte injury induced by myocardial contrast material-enhanced echocardiography (ie, myocardial contrast echocardiography) in rats and to ascertain the influences of contrast material dose and ultrasound exposure on this injury. MATERIALS AND METHODS All animal procedures were approved by the university committee for the use and care of animals. Myocardial contrast echocardiography with 1:4 electrocardiographic (ECG) triggering was performed at 1.5 MHz in 61 anesthetized rats. Evans blue (EB) dye was injected as the vital stain for cardiomyocyte injury. At the start of myocardial contrast echocardiography, which lasted 10 minutes, perflutren lipid microsphere-based contrast material was infused through the tail vein for 5 minutes. Premature heartbeats were counted from the ECG record. The numbers of EB-stained cells counted on sections of heart specimens obtained 24 hours after myocardial contrast echocardiography and then either fresh frozen or embedded in paraffin were determined by using fluorescence microscopy. Results were compared statistically by using t tests and Mann-Whitney rank sum tests. RESULTS EB-stained cells were concentrated in the anterior region of the myocardium. In the paraffin-embedded specimens, EB-stained cells were often accompanied by but largely separate from areas of inflammatory cell infiltration. At end-systolic triggering with a 50 microL/kg dose of microsphere contrast material, the EB-stained cell count increased with increasing peak rarefactional pressure amplitude, with significantly increased cell counts at 1.6 MPa (P < .02) and 2.0 MPa (P < .005) relative to the cell counts at sham myocardial contrast echocardiography. Premature heartbeats had a similar exposure-response relationship; however, number of premature heartbeats and EB-stained cell count did not appear to be directly related (coefficient of determination r2 = 0.03). The EB-stained cell counts at end-diastolic triggering were not significantly different from those at end-systolic triggering (P > .1). EB-stained cell counts increased with increasing contrast material dose, from 10 to 50 microL/kg, at 2.0 MPa. CONCLUSION Cardiomyocyte injury was induced by the interaction of ultrasound pulses with contrast agent microbubbles during myocardial contrast echocardiography in rats, and the numbers of injured cells increased with increasing contrast agent dose and ultrasound exposure.
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Affiliation(s)
- Douglas L Miller
- Department of Radiology, University of Michigan Medical Center, 3315 Kresge III, 200 Zina Pitcher Pl, Ann Arbor, MI 48109-0553, USA.
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159
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Hohimer AR, Davis LE, Hatton DC. Repeated daily injections and osmotic pump infusion of isoproterenol cause similar increases in cardiac mass but have different effects on blood pressure. Can J Physiol Pharmacol 2005; 83:191-7. [PMID: 15791293 DOI: 10.1139/y04-137] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We found in mice that repeated single daily subcutaneous (s.c.) isoproterenol (ISO) injections, like constant infusions using osmotic minipumps, caused increased biventricular mass or weight relative to body weight (VW/BW). We found that 5 (1/d) s.c. injections of 2, 10, or 20 microg/g body weight caused equivalent VW/BW increases as compared with 5-d infusions at 20 microg/(g.d)). While it is often presumed that ISO elicits hypertrophy by a direct effect on the myocytes, growth may also be secondary to systemic hemodynamic effects. The 2 modes of ISO administration had different effects on mean arterial blood pressure (MABP) and heart rate. Using telemetry we observed that single injections of ISO (0, 0.5, 2, and 10 microg/g) were associated with hypotension and tachycardia with a duration but not a magnitude that was dose dependent. MABP dropped rapidly to 60 mm Hg for more than 2 h at the highest dose. Constant s.c. infusion of ISO at 20 microg/(g.d) initially lowered MABP to about 70 mm Hg for 24 h. At 48 h MABP was normal, but rose 10 mm Hg higher than baseline by day 5. Thus, different routes of administration of ISO that cause comparable increases in VW/BW had different effects on MABP. Thus when evaluating mouse models of ISO-induced cardiac hypertrophy, both repeated daily injections or infusions can cause similar increases in VW/BW, but the daily doses that are required are not the same. Furthermore, these different routes of administration have different hemodynamic sequelae and could potentially evoke different cardiac phenotypes.
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Affiliation(s)
- A Roger Hohimer
- Department of OB/GYN, Division of Perinatology, Oregon Health & Science University, Portland 97239-3098, USA.
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160
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Gregorevic P, Ryall JG, Plant DR, Sillence MN, Lynch GS. Chronic β-agonist administration affects cardiac function of adult but not old rats, independent of β-adrenoceptor density. Am J Physiol Heart Circ Physiol 2005; 289:H344-9. [PMID: 15734875 DOI: 10.1152/ajpheart.01254.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although β-adrenoceptor agonists have clinical merit for attenuating the age-related loss of skeletal muscle mass and strength (sarcopenia), potential cardiac-related side effects may limit their clinical application. The aim of this study was to determine whether chronic β-agonist administration impairs cardiac function in adult or aged rats. Adult (16 mo) and aged (28 mo) Fischer 344 rats were treated with fenoterol (1.4 mg·kg−1·day−1 ip) or vehicle for 4 wk. Heart function was assessed in vitro before analyses of cardiac structure and β-adrenoceptor density. Heart mass increased 17% and 25% in fenoterol-treated adult and aged rats, respectively. The increased heart mass in aged, but not adult, rats was associated with a relative increase in collagen content. Cardiac hypertrophy in adult rats was associated with an increase in left ventricular developed pressure, a marked reduction in cardiac output, and a reduction in coronary flow per unit heart mass. In contrast, negligible differences in ventricular function were observed in fenoterol-treated aged rats. The differential effect on contractile function was not associated with age-related differences in β-adrenoceptor density but, rather, an age-related increase in downregulation after treatment. Our results show that chronic β-agonist treatment impairs cardiac function to a greater extent in adult than in aged rats. These results provide important information regarding the potential effects of chronic β-agonist use on cardiac function and the future development of safe and effective treatments for sarcopenia.
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Affiliation(s)
- Paul Gregorevic
- Dept. of Physiology, The Univ. of Melbourne, Victoria 3010, Australia
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161
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Morales MO, Price RL, Goldsmith EC. Expression of Discoidin Domain Receptor 2 (DDR2) in the developing heart. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2005; 11:260-7. [PMID: 16060979 DOI: 10.1017/s1431927605050518] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Accepted: 11/11/2004] [Indexed: 05/03/2023]
Abstract
Interactions between cells and the surrounding extracellular matrix are important for a number of developmental events. In the heart, cardiac fibroblasts produce the majority of extracellular matrix proteins, particularly collagen types I and III. Cells originating from the proepicardial organ migrate over the surface of the heart, invade the underlying myocardium and ultimately give rise to smooth muscle cells, fibroblasts, and coronary endothelium. Although integrin expression in the developing heart has been well characterized, the expression of Discoidin Domain Receptor 2 (DDR2) remains to be defined. Using confocal microscopy, the expression of DDR2 was examined at several points during cardiac development. Initially, DDR2 expression was detected on the epicardial surface of the heart and on endothelial and mesenchymal cells within the cardiac cushions. As development progressed, DDR2 expression increased at localized regions in the apex and atrioventricular sulcus, although this expression decreased from epicardial to endocardial surface. Eventually, DDR2 expression spanned the myocardial free wall and was detected within the septum. Not until postnatal development was DDR2 expression detected uniformly throughout the myocardium and this distribution was maintained in the adult heart. In summary, the data presented demonstrate that the distribution of DDR2-positive cells changes within the heart during development.
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Affiliation(s)
- Mary O Morales
- Department of Cell and Developmental Biology & Anatomy, University of South Carolina School of Medicine, Columbia, SC 29209, USA
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162
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Zhang R, Khoo MSC, Wu Y, Yang Y, Grueter CE, Ni G, Price EE, Thiel W, Guatimosim S, Song LS, Madu EC, Shah AN, Vishnivetskaya TA, Atkinson JB, Gurevich VV, Salama G, Lederer WJ, Colbran RJ, Anderson ME. Calmodulin kinase II inhibition protects against structural heart disease. Nat Med 2005; 11:409-17. [PMID: 15793582 DOI: 10.1038/nm1215] [Citation(s) in RCA: 439] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Accepted: 02/24/2005] [Indexed: 01/16/2023]
Abstract
Beta-adrenergic receptor (betaAR) stimulation increases cytosolic Ca(2+) to physiologically augment cardiac contraction, whereas excessive betaAR activation causes adverse cardiac remodeling, including myocardial hypertrophy, dilation and dysfunction, in individuals with myocardial infarction. The Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) is a recently identified downstream element of the betaAR-initiated signaling cascade that is linked to pathological myocardial remodeling and to regulation of key proteins involved in cardiac excitation-contraction coupling. We developed a genetic mouse model of cardiac CaMKII inhibition to test the role of CaMKII in betaAR signaling in vivo. Here we show CaMKII inhibition substantially prevented maladaptive remodeling from excessive betaAR stimulation and myocardial infarction, and induced balanced changes in excitation-contraction coupling that preserved baseline and betaAR-stimulated physiological increases in cardiac function. These findings mark CaMKII as a determinant of clinically important heart disease phenotypes, and suggest CaMKII inhibition can be a highly selective approach for targeting adverse myocardial remodeling linked to betaAR signaling.
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Affiliation(s)
- Rong Zhang
- Department of Medicine, Vanderbilt University School of Medicine, 2220 Pierce Avenue, Nashville, Tennessee 37232-6300, USA
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163
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Faulx MD, Ernsberger P, Vatner D, Hoffman RD, Lewis W, Strachan R, Hoit BD. Strain-dependent beta-adrenergic receptor function influences myocardial responses to isoproterenol stimulation in mice. Am J Physiol Heart Circ Physiol 2005; 289:H30-6. [PMID: 15749746 DOI: 10.1152/ajpheart.00636.2004] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recently, we showed that compared with the A/J inbred mouse strain, C57BL/6J (B6) mice have an athlete's cardiac phenotype. We postulated that strain differences would result in greater left ventricular (LV) hypertrophy in response to isoproterenol in B6 than A/J mice and tested the hypothesis that a differential response could be explained partly by differences in beta-adrenergic receptor (beta-AR) density and/or coupling. A/J and B6 mice were randomized to receive daily isoproterenol (100 mg/kg sc) or isovolumic vehicle for 5 days. Animals were studied using echocardiography, tail-cuff blood pressure, histopathology, beta-AR density and percent high-affinity binding, and basal and stimulated adenylyl cyclase activities. One hundred twenty-eight mice (66 A/J and 62 B6) were studied. Isoproterenol-treated A/J mice demonstrated greater percent increases in echocardiographic LV mass/body weight (97 +/- 11 vs. 20 +/- 10%, P = 0.001) and in gravimetric heart mass/body weight versus same-strain controls than B6 mice. Histopathology scores (a composite of myocyte hypertrophy, nuclear changes, fibrosis, and calcification) were greater in isoproterenol-treated A/J vs. B6 mice (2.8 +/- 0.2 vs.1.9 +/- 0.3, P < 0.05), as was quantitation of myocyte damage (22.3 +/- 11.5 vs. 4.3 +/- 3.5%). Interstrain differences in basal beta-AR density, high-affinity binding, and adenylyl cyclase activity were not significant. However, whereas isoproterenol-treated A/J mice showed nonsignificant increases in all beta-AR activity measures, isoproterenol-treated B6 mice had lower beta-AR density (57 +/- 6 vs. 83 +/- 8 fmol/mg, P < 0.05), percent high-affinity binding (15 +/- 2 vs. 26 +/- 3%, P < 0.005), and GTP + isoproterenol-stimulated adenylyl cyclase activity (10 +/- 1.1 vs. 5.8 +/- 1.5 pmol cAMP.mg(-1).min(-1)) compared with controls. High-dose, short-term isoproterenol produces greater macro- and microscopic cardiac hypertrophy and injury in A/J than B6 mice. A/J mice, unlike B6 mice, do not experience beta-AR downregulation or uncoupling in response to isoproterenol. Abnormalities in beta-adrenergic regulation may contribute to strain-related differences in the vulnerability to isoproterenol-induced cardiac changes.
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Affiliation(s)
- Michael D Faulx
- Division of Cardiology, Dept. of Medicine, Univ. Hospitals of Cleveland and Case Western Reserve Univ., MS 5038, 11100 Euclid Ave., Cleveland, OH 44106-5038, USA
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164
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Yeh CK, Ghosh PM, Dang H, Liu Q, Lin AL, Zhang BX, Katz MS. beta-Adrenergic-responsive activation of extracellular signal-regulated protein kinases in salivary cells: role of epidermal growth factor receptor and cAMP. Am J Physiol Cell Physiol 2005; 288:C1357-66. [PMID: 15689414 DOI: 10.1152/ajpcell.00370.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The beta-adrenergic receptor agonist isoproterenol exerts growth-promoting effects on salivary glands. In this study, activation of ERKs, members of the mitogen-activated protein kinase family, by isoproterenol was examined in a human salivary gland cell line (HSY). Immunoblot analysis indicated that isoproterenol (10(-5) M) induced transient activation of ERK1/2 (4.4-fold relative to basal at 10 min) similar to that caused by EGF (6.7 fold). Isoproterenol, like EGF, also induced phosphorylation of the EGF receptor. However, inhibition of EGF receptor phosphorylation by the tyrphostin AG-1478 only partially attenuated isoproterenol-induced ERK phosphorylation, whereas EGF-responsive ERK activation was completely blocked. The G(i) inhibitor pertussis toxin also caused partial inhibition of isoproterenol-stimulated ERK activation. The cAMP analog 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate (CPT-cAMP) and the cAMP-elevating agents IBMX and cholera toxin produced transient ERK1/2 activation, similar to the effect of isoproterenol, in HSY cells. The stimulatory effects of isoproterenol and cAMP on ERK phosphorylation were not reduced by the PKA inhibitor H-89, whereas the Src family inhibitor 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidase (PP2) and transfection of a dominant-negative Src construct diminished isoproterenol-induced ERK activation. Isoproterenol induced marked overexpression of the cell growth-related adhesion molecule CD44, and this effect of isoproterenol was abolished by the ERK pathway inhibitor PD-98059. In summary, we show a dual mechanism of isoproterenol-induced ERK phosphorylation in HSY cells-one pathway mediated by EGF receptor transactivation and the other by an EGF receptor-independent pathway possibly mediated by cAMP. Our results also suggest that isoproterenol-induced growth of salivary tissue may involve ERK-mediated CD44 expression.
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Affiliation(s)
- Chih-Ko Yeh
- Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, 7400 Merton Minter Blvd., San Antonio, TX 78229-4404, USA
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165
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Cicoira M, Rossi A, Bonapace S, Zanolla L, Golia G, Franceschini L, Caruso B, Marino PN, Zardini P. Independent and additional prognostic value of aminoterminal propeptide of type III procollagen circulating levels in patients with chronic heart failure. J Card Fail 2004; 10:403-11. [PMID: 15470651 DOI: 10.1016/j.cardfail.2004.01.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND In chronic heart failure (CHF), changes in the extracellular space contribute to cardiac dysfunction. We aimed to determine whether aminoterminal-propeptide of type III procollagen (PIIINP), a marker of extracellular matrix turnover, might provide prognostic information in CHF patients. METHODS AND RESULTS A total of 101 consecutive CHF patients (mean age 61.7 +/- 8.7 years, 88% males) were followed up between 1999 and 2001. The combined endpoint of the study was death and hospitalization for heart failure. During follow-up there were 15 deaths and 11 hospitalizations for worsening heart failure. At the survival analysis, age (P = .02), New York Heart Association class (P = .014), s-creatinine (P = .014), plasma-PIIINP (p-PIIINP) levels (P = .005), left ventricular ejection fraction (LVEF) (P = .0002), and a restrictive mitral filling pattern (P = .0003) predicted event-free survival. At the multivariate analysis, p-PIIINP levels predicted outcome independently of other clinical variables, hormones, and echocardiographic and exercise testing variables (P < .05 in all models). In patients with LVEF <31%, the presence of p-PIIINP >4.7 microg/L levels was significantly associated with a higher risk of death and hospitalization as compared with the other patients (event-free survival rate at 12 months: 45% versus 95%; at 24 months: 27% versus 88%; at 36 months: 18% versus 85%, P < .0001). CONCLUSIONS In patients with CHF, PIIINP levels predict outcome independently of clinical status, hemodynamics and hormonal activation. PIIINP levels provide additional prognostic information to that of left ventricular function alone, suggesting that it may reflect more than cardiac extracellular matrix turnover.
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Affiliation(s)
- Mariantonietta Cicoira
- Dipartimento di Scienze Biomediche e Chirurgiche, Sezione di Cardiologia, Università degli Studi di Verona, Italy
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166
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Ohta T, Hasebe N, Tsuji S, Izawa K, Jin YT, Kido S, Natori S, Sato M, Kikuchi K. Unequal effects of renin-angiotensin system inhibitors in acute cardiac dysfunction induced by isoproterenol. Am J Physiol Heart Circ Physiol 2004; 287:H2914-21. [PMID: 15297251 DOI: 10.1152/ajpheart.00221.2004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several clinical trials have demonstrated that angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II type 1 receptor blocker (ARB) are equally effective in the treatment of chronic heart failure. However, this has not been confirmed for acute cardiac dysfunction. We examined whether ACEI or ARB prevents isoproterenol-induced acute left ventricular (LV) dysfunction in dogs. LV dysfunction induced by a large dose of isoproterenol (1 microg.kg(-1).min(-1), 3-h infusion) was compared in dogs treated with ACEI (temocaprilat) or ARB (olmesartan). Atrial pacing induced a constant heart rate and use of adjustable aortic banding provided a nearly constant afterload. LV systolic function (LV dP/dt, fractional shortening, and ejection fraction) and diastolic function (tau and LV end-diastolic pressure) were significantly deteriorated after isoproterenol infusion. The LV dysfunction was almost totally prevented by ARB but was only partially prevented by ACEI. The partial effect of ACEI was complemented by cotreatment with HOE-140, a bradykinin B2 receptor antagonist. At baseline, the response to low doses of isoproterenol was significantly attenuated by ACEI but not by ARB, and the ACEI-induced attenuation was totally abolished by cotreatment with HOE-140. The response to isoproterenol was significantly attenuated after 3 h of excess isoproterenol loading, and it was almost completely preserved by ARB but not by ACEI. In conclusion, acute LV dysfunction and beta-adrenergic desensitization induced by excess isoproterenol administration were almost totally prevented by ARB but only partially prevented by ACEI. These differences were attributable at least in part to bradykinin pathways activated by ACEI administration in acute LV dysfunction.
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Affiliation(s)
- Takafumi Ohta
- First Dept. of Internal Medicine, Asahikawa Medical College, 2-1-1 Midorigaoka higashi, Asahikawa, Hokkaido 078-8510, Japan
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167
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Abstract
The presence of a diabetic cardiomyopathy, independent of hypertension and coronary artery disease, is still controversial. This systematic review seeks to evaluate the evidence for the existence of this condition, to clarify the possible mechanisms responsible, and to consider possible therapeutic implications. The existence of a diabetic cardiomyopathy is supported by epidemiological findings showing the association of diabetes with heart failure; clinical studies confirming the association of diabetes with left ventricular dysfunction independent of hypertension, coronary artery disease, and other heart disease; and experimental evidence of myocardial structural and functional changes. The most important mechanisms of diabetic cardiomyopathy are metabolic disturbances (depletion of glucose transporter 4, increased free fatty acids, carnitine deficiency, changes in calcium homeostasis), myocardial fibrosis (association with increases in angiotensin II, IGF-I, and inflammatory cytokines), small vessel disease (microangiopathy, impaired coronary flow reserve, and endothelial dysfunction), cardiac autonomic neuropathy (denervation and alterations in myocardial catecholamine levels), and insulin resistance (hyperinsulinemia and reduced insulin sensitivity). This review presents evidence that diabetes is associated with a cardiomyopathy, independent of comorbid conditions, and that metabolic disturbances, myocardial fibrosis, small vessel disease, cardiac autonomic neuropathy, and insulin resistance may all contribute to the development of diabetic heart disease.
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Affiliation(s)
- Zhi You Fang
- University of Queensland, Brisbane, 4012, Australia
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168
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Geng B, Chang L, Pan C, Qi Y, Zhao J, Pang Y, Du J, Tang C. Endogenous hydrogen sulfide regulation of myocardial injury induced by isoproterenol. Biochem Biophys Res Commun 2004; 318:756-63. [PMID: 15144903 DOI: 10.1016/j.bbrc.2004.04.094] [Citation(s) in RCA: 316] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2004] [Indexed: 01/12/2023]
Abstract
Previous work has shown that the endogenous cystathionine gamma-synthase (CSE)/hydrogen sulfide (H(2)S) pathway participates in the regulation of cardiac contraction. We hypothesized that the pathway might participate in the pathophysiological regulation of ischemic heart disease. Isoproterenol injection of rat hearts induced a myocardial ischemic injury model, with reduced myocardial and plasma H(2)S levels, decreased CSE activity, and upregulated CSE gene expression. Exogenous administration of the H(2)S donor NaHS reduced the mortality rate; increased left-ventricular pressure development and left-ventricular-end systolic pressure; and decreased left-ventricular-end diastolic pressure (LVEDP) and subendocardial necrosis, capillary dilatation, leukocytic infiltration, fibroblast swelling, and fibroblastic hyperplasia. As well, production of lipid peroxidation, including myocardial malondialdehyde (MDA), and plasma MDA and conjugated diene, was reduced. Oxidative stress injury is an important mechanism of isoproterenol-induced myocardial injury. In vitro experiments revealed that NaHS might antagonize myocyte MDA production by oxygen-free radicals and that NaHS directly scavenged hydrogen peroxide and superoxide anions. Our results suggest that the endogenous CSE/H(2)S pathway contributes to the pathogenesis of isoproterenol-induced myocardial injury. Administration of exogenous H(2)S effectively protects myocytes and contractile activity, at least by its direct scavenging of oxygen-free radicals and reducing the accumulation of lipid peroxidations.
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Affiliation(s)
- Bin Geng
- Department of Physiology, Peking University Health Science Center, PR China
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169
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Dudnakova TV, Lakomkin VL, Tsyplenkova VG, Shekhonin BV, Shirinsky VP, Kapelko VI. Alterations in myocardial ultrastructure and protein expression after a single injection of isoproterenol. Mol Cell Biochem 2004; 252:173-81. [PMID: 14577591 DOI: 10.1023/a:1025579624695] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Immunochemical and electron microscopic characterization of rat myocardium was conducted 2 h and 3 weeks after a single injection of isoproterenol in rats. The relative content of several myospecific proteins (KRP--kinase-related protein, desmin), cytoskeletal proteins (tubulin, vinculin, myosin light chain kinase--MLCK) and extracellular matrix protein fibronectin was determined by immunoblotting. Two hours after injection of 50 mg/kg isoproterenol a destruction of some cardiomyocytes, contracture of myofibrils and mild edema of intercellular space was observed. The content of all the studied proteins except KRP decreased below control levels. This situation sustained 3 weeks after injection and paralleled alterations in cardiomyocyte ultrastructure. Areas of myofibrillar contracture and lysis were noted, glycogen granules were sparse; mitochondria contained arrow-like inclusions that are characteristic for calcium overload, also huge mitochondria contacting each other by specialized intermitochondrial contacts were detected. Clumps of unripe elastic fibers in enlarged intercellular space were combined with increased deposition of collagens type I and III forming areas of fibrosis. The smaller dosage of isoproterenol (10 mg/kg) rendered no significant damage in the acute postinjection period but 3 weeks later it induced the thickening of extracellular matrix around cardiac cells and the increase in KRP and tubulin content by 26 and 32%, correspondingly. MLCK levels remained depressed throughout the experiment. The rise in KRP expression was also observed after the addition of isoproterenol to cultured chicken embryo cardiomyocytes. Obtained results indicate that even a single injection of isoproterenol creates long lasting structural alterations in cardiac muscle accompanied by the increased expression of extracellular matrix proteins and several sarcoplasmic proteins apparently involved in hypertrophic response of cardiomyocytes.
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Affiliation(s)
- Tatyana V Dudnakova
- Institute of Experimental, Russian Cardiological Scientific and Productive Complex, Moscow, Russia
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170
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Goldspink DF, Burniston JG, Ellison GM, Clark WA, Tan LB. Catecholamine-induced apoptosis and necrosis in cardiac and skeletal myocytes of the rat in vivo: the same or separate death pathways? Exp Physiol 2004; 89:407-16. [PMID: 15131072 DOI: 10.1113/expphysiol.2004.027482] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
High levels of catecholamines are myotoxic but the relative amounts of apoptosis and necrosis have not been established in vivo in cardiac and skeletal muscles. Immunohistochemistry was used to detect and quantify myocyte-specific necrosis (myosin antibody in vivo) and apoptosis (caspase-3 antibody in vitro) in the heart and soleus muscles of male Wistar rats that had received single subcutaneous injections of isoprenaline over the range 1 microg to 5 mg [kg body weight (BW)](-1). Peak myocyte apoptosis occurred 3-6 h after, and necrosis 18 h after, a single injection of 5 mg (kg BW)(-1) isoprenaline in vivo. In the heart myocyte death was mediated through the beta1-adrenergic receptor whereas myocyte death in the soleus muscle was mediated through the beta2-adrenergic receptor. Cardiomyocyte death was heterogeneously distributed throughout the heart, being greatest in the left ventricle (LV) subendocardium and peaking close to the apex, but with significantly more necrosis than apoptosis. Extensive co-localization of caspase-3 and myosin labelling was found in the myocytes of both the heart and the slow-twitch soleus muscle. This, together with similar spatial distributions and responses to catecholamine doses, suggests that either caspase-3 activation occurs in necrotic as well as apoptotic myocytes or that a large proportion of apoptotic myocytes progress to secondary necrosis in vivo.
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Affiliation(s)
- David F Goldspink
- The Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, 15-21 Webster Street, Liverpool L3 2ET, UK.
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171
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Tan LB, Williams SG, Goldspink DF. From CONSENSUS to CHARM—how do ACEI and ARB produce clinical benefits in CHF? Int J Cardiol 2004; 94:137-41. [PMID: 15093971 DOI: 10.1016/j.ijcard.2003.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2003] [Accepted: 10/23/2003] [Indexed: 10/26/2022]
Abstract
Two decades of research from CONSENSUS to CHARM using modulators of the renin-angiotensin-aldosterone system (RAAS) in chronic heart failure (CHF) patients have shown convincing clinical benefits, but the majority of clinicians prescribing these drugs are still unclear about what mechanisms are responsible for the observed benefits. Of the candidate mechanisms hitherto proposed, there emerges a theme that best fits the spectrum of known factors from pathophysiology of heart failure to how the drugs enhance longevity of patients. This concept can be summarised as follows: after the onset of heart failure, neurohormones are activated resulting in raised levels of angiotensin, aldosterone and catecholamines, which are all known cardiotoxic agents. Cumulatively over time, they are responsible for accelerated cardiomyocyte attrition, manifesting as a faster reduction of cardiac pumping reserve, leading to worsening heart failure, more neurohormonal activation, thus propagating a vicious cycle spiralling towards an earlier fatality. The vicious cycle can be interrupted by dampening the excessive neurohormonal activities, thereby minimising cardiomyocyte losses and preserving cardiac functional reserve for longer. This culminates in maintenance of a reasonable quality of life and enhanced longevity. Such a mechanistic understanding would enable clinicians to have a better perspective on how to apply data from various clinical trials involving these drugs into clinical practice, to optimise and tailor therapy to the individual patient so that each patient can gain maximal benefits.
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172
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Costoli T, Bartolomucci A, Graiani G, Stilli D, Laviola G, Sgoifo A. Effects of chronic psychosocial stress on cardiac autonomic responsiveness and myocardial structure in mice. Am J Physiol Heart Circ Physiol 2004; 286:H2133-40. [PMID: 14962836 DOI: 10.1152/ajpheart.00869.2003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Repeated single exposures to social stressors induce robust shifts of cardiac sympathovagal balance toward sympathetic dominance both during and after each agonistic interaction. However, little evidence is available regarding possible persistent pathophysiological changes due to chronic social challenge. In this study, male CD-1 mice (n = 14) were implanted with a radiotelemetry system for electrocardiographic recordings. We assessed the effects of chronic psychosocial stress (15-day sensory contact with a dominant animal and daily 5-min defeat episodes) on 1) sympathovagal responsiveness to each defeat episode, as measured via time-domain indexes of heart rate variability (R-R interval, standard deviation of R-R interval, and root mean square of successive R-R interval differences), 2) circadian rhythmicity of heart rate across the chronic challenge (night phase, day phase, and rhythm amplitude values), and 3) amount of myocardial structural damage (volume fraction, density, and extension of fibrosis). This study indicated that there was habituation of acute cardiac autonomic responsiveness, i.e., the shift of sympathovagal balance toward sympathetic dominance was significantly reduced across repeated defeat episodes. Moreover, animals exhibited significant changes in heart rate rhythmicity, i.e., increments in day and night values and reductions in the rhythm amplitude, but these were limited to the first 5 days of chronic psychosocial stress. The volume fraction of fibrosis was sixfold larger than in control animals, because of the appearance of many microscopic scarrings. In summary, although mice appeared to adapt to chronic psychosocial stress in terms of acute cardiovascular responsiveness and heart rate rhythmicity, structural alterations occurred at the myocardial level.
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Affiliation(s)
- Tania Costoli
- Dipartimento di Biologia Evolutiva e Funzionale, Università di Parma, Parco Area delle Scienze 11A, 43100 Parma, Italy.
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173
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Bos R, Mougenot N, Médiani O, Vanhoutte PM, Lechat P. Potassium Canrenoate, an Aldosterone Receptor Antagonist, Reduces Isoprenaline-Induced Cardiac Fibrosis in the Rat. J Pharmacol Exp Ther 2004; 309:1160-6. [PMID: 14764658 DOI: 10.1124/jpet.103.063388] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of the present study was to determine whether the administration of an antagonist of aldosterone could prevent the fibrosis induced by an acute injection of isoprenaline. Male Wistar rats were submitted to one subcutaneous injection of isoprenaline (400 mg/kg) and were simultaneously treated with potassium canrenoate in drinking water (20 mg/kg/day) started 5 days before the injection of isoprenaline. Two months later, echocardiographic and hemodynamic measurements were performed. Then, the heart was prepared for morphometric histology and quantification of fibrosis in the left ventricle. Heart and left ventricular weights were increased significantly by isoprenaline. Potassium canrenoate attenuated this increase. The administration of isoprenaline increased significantly end diastolic diameter and end systolic volume compared with control. These changes were increased further with the addition of potassium canrenoate. In contrast, the fibrosis induced by isoprenaline was reduced significantly by potassium canrenoate at the three section levels. Potassium canrenoate attenuated the fibrosis but not the enhanced dilatation of the left ventricle induced by isoprenaline.
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Affiliation(s)
- Romain Bos
- Service de Pharmacologie, CHU Pitié Salpêtrière, 47 boulevard de l'Hôpital, 75651 Paris cedex 13, France
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174
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Tan LB, Schlosshan D, Williams SG. The benefits of valsartan in the treatment of heart failure: results from Val-HeFT. Int J Clin Pract 2004; 58:184-91. [PMID: 15055867 DOI: 10.1111/j.1368-5031.2004.0134.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Angiotensin II receptor blockers (ARBs) are the most recent class of anti-hypertensive drug to enter clinical use for chronic heart failure (CHF). In the landmark Valsartan Heart Failure Trial (Val-HeFT), valsartan reduced the risk of the combined endpoint of all-cause mortality and morbidity by 13.2% over a 2-year follow-up. Although it significantly improved a pre-specified primary endpoint, it did not improve the endpoint of all-cause mortality. Valsartan administered to patients not receiving angiotensin-converting enzyme inhibitors (ACEI) at baseline reduced the endpoint of all-cause mortality by 33% and the combined endpoint of mortality and morbidity by 44%, compared with placebo. Based on these findings, valsartan became the first ARB to be approved by the US Food and Drug Administration for the treatment of New York Heart Association class II-IV HF in patients who are intolerant of ACEIs. This review provides a summary of the key Val-HeFT results and their implications in the treatment of CHF patients.
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Affiliation(s)
- L B Tan
- Molecular Vascular Medicine, University of Leeds, G Floor Martin Wing, Leeds General Infirmary, George Street, Leeds, UK
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175
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Ocaranza MP, Díaz-Araya G, Carreño JE, Muñoz D, Riveros JP, Jalil JE, Lavandero S. Polymorphism in gene coding for ACE determines different development of myocardial fibrosis in rats. Am J Physiol Heart Circ Physiol 2004; 286:H498-506. [PMID: 14527934 DOI: 10.1152/ajpheart.00102.2003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In humans, the effect of angiotensin-converting enzyme (ACE) gene polymorphisms in cardiovascular disease is still controversial. In the rat, a microsatellite marker in the ACE gene allows differentiation of the ACE gene polymorphism among strains with different ACE levels. We tested the hypothesis that this ACE gene polymorphism determines the extent of cardiac fibrosis induced by isoproterenol (Iso) in the rat. We used a male F2generation (homozygous LL and BB ACE genotypes determined by polymerase chain reaction) derived from two rat strains [Brown-Norway (BB) and Lewis (LL)] that differ with respect to their plasma ACE activities. For induction of left ventricular (LV) hypertrophy (LVH) and cardiac fibrosis, rats were infused with Iso (5 mg·kg–1·day–1) or saline (control) for 10 days and euthanized at day 1 after the last injection. The interstitial collagen volumetric fraction (ICVF), collagen I, and fibronectin content, but not collagen III content, were significantly higher in the homozygous BB rats than in homozygous LL rats. Differences in metalloprotease (MMP)-9, but not in MMP-2 activities as well as in cardiac cell proliferation, were also detected between LL and BB rats treated with Iso. LV ACE activity was higher in BB rats than LL rats and correlated with ICVF ( r = 0.61, P < 0.002). No changes were observed in plasma ACE activities, ANG II plasma or LV levels, plasma renin activity, and ACE and ANG II type 1 receptor (AT1R) mRNA levels in the LV of rats with the two different ACE polymorphisms. Iso induced a similar degree of LVH [assessed by an increase in LV weight 100 per body weight, LV-to-right ventricle (RV) ratio, and LV protein content] in LL and BB rats. We concluded that rats in the F2generation with high plasma ACE activity developed more fibrosis but to a similar degree of LVH compared with rats with low plasma ACE activity.
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Affiliation(s)
- María Paz Ocaranza
- Departamento Enfermedades Cardiovasculares, Escuela de Medicina, P. Universidad Católica de Chile
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176
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Bua E, McKiernan SH, Aiken JM. Calorie restriction limits the generation but not the progression of mitochondrial abnormalities in aging skeletal muscle. FASEB J 2004; 18:582-4. [PMID: 14734641 DOI: 10.1096/fj.03-0668fje] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The effect of early-onset calorie restriction and aging on the accumulation of electron transport system (ETS) abnormalities was studied in rat skeletal muscle. Rectus femoris and vastus lateralis muscle fibers were analyzed for cytochrome c oxidase (COX) and succinate dehydrogenase (SDH) enzyme activities. Fibers displaying COX negative and SDH hyper reactive (COX-/SDH++) phenotype were followed through 1000-2000 micrometers to determine the frequency and length of these abnormalities as well as the physiological impact on fiber structure. Calorie restricted rats had fewer ETS abnormal muscle fibers. The mean length of ETS abnormal regions in ad libitum rat muscle fibers was similar to calorie restricted rat muscles. ETS abnormal fibers from both diet groups exhibited intra-fiber atrophy. A negative correlation between ETS abnormality length and fiber cross-sectional area (CSA) ratio was observed in both ad libitum and calorie- restricted rats. Although calorie restriction reduced the number of ETS abnormalities, it did not affect the length or associated fiber atrophy of ETS abnormal regions once the abnormality was established. Thus, calorie restriction affects the onset but not the progression of electron transport system abnormalities, thereby, limiting a process that ultimately results in fiber breakage and fiber loss.
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MESH Headings
- Aging/pathology
- Animals
- Biomarkers
- Body Weight
- Caloric Restriction
- Crosses, Genetic
- DNA, Mitochondrial/genetics
- Electron Transport
- Electron Transport Complex IV/analysis
- Electron Transport Complex IV/genetics
- Male
- Mitochondria, Muscle/enzymology
- Mitochondria, Muscle/pathology
- Muscle Fibers, Skeletal/classification
- Muscle Fibers, Skeletal/enzymology
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/growth & development
- Muscle, Skeletal/ultrastructure
- Muscular Atrophy/enzymology
- Muscular Atrophy/pathology
- Muscular Atrophy/prevention & control
- Organ Size
- Rats
- Rats, Inbred BN
- Rats, Inbred F344
- Succinate Dehydrogenase/analysis
- Succinate Dehydrogenase/genetics
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Affiliation(s)
- Entela Bua
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA
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177
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González A, López B, Díez J. Fibrosis in hypertensive heart disease: role of the renin-angiotensin-aldosterone system. Med Clin North Am 2004; 88:83-97. [PMID: 14871052 DOI: 10.1016/s0025-7125(03)00125-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Structural homogeneity of cardiac tissue is governed by mechanical and humoral factors that regulate cell growth, apoptosis, phenotype, and extracellular matrix turnover. ANGII has endocrine, autocrine, and paracrine properties that influence the behavior of cardiac cells and matrix by AT1 receptor binding. Various paradigms have been suggested, including ANGII-mediated up-regulation of collagen types I and III formation and deposition in cardiac conditions, such as HHD. A growing body of evidence, however, deals with the potential role of aldosterone, either local or systemic, in inducing cardiac fibrosis. Aldosterone might also mediate the profibrotic actions of ANGII. To reduce the risk of heart failure that accompanies HHD, its adverse structural remodeling (eg, myocardial hypertrophy and fibrosis) must be targeted for pharmacologic intervention. Cardioprotective agents must reverse not only the exaggerated growth of cardiac cells, but also regress existing abnormalities in fibrillar collagen. Available experimental and clinical data suggest that agents interfering with ACE, the AT1 receptor, or the mineralocorticoid receptor may provide such a cardioprotective effect.
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Affiliation(s)
- Arantxa González
- Area of Cardiovascular Pathophysiology, Centre for Applied Medical Research, University of Navarra, C. Irunlarrea 1, 31080 Pamplona, Spain
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178
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Zahabi A, Picard S, Fortin N, Reudelhuber TL, Deschepper CF. Expression of constitutively active guanylate cyclase in cardiomyocytes inhibits the hypertrophic effects of isoproterenol and aortic constriction on mouse hearts. J Biol Chem 2003; 278:47694-9. [PMID: 14500707 DOI: 10.1074/jbc.m309661200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Evidence from several rodent models has suggested that a reduction of either atrial natriuretic peptide or its receptor in the heart affects cardiac remodeling by promoting the onset of cardiac hypertrophy. The atrial natriuretic peptide receptor mediates signaling at least in part via the generation of intracellular cyclic GMP. To directly test whether accumulation of intracellular cyclic GMP conveys protection against cardiac hypertrophy, we engineered transgenic mice that overexpress a catalytic fragment of constitutively active guanylate cyclase domain of the atrial natriuretic peptide receptor in a cardiomyocyte-specific manner. Expression of the transgene increased the intracellular concentration of cyclic GMP specifically within cardiomyocytes and had no detectable effect on cardiac performance under basal conditions. However, expression of the transgene attenuated the effects of the pharmacologic hypertrophic agent isoproterenol on cardiac wall thickness and prevented the onset of the fetal gene expression program normally associated with cardiac hypertrophy. Likewise, expression of the transgene inhibited the hypertrophic effects of abdominal aortic constriction, since it abolished its effects on ventricular wall thickness and greatly attenuated its effects on cardiomyocyte size. Altogether, our results suggest that cyclic GMP is a cardioprotective agent against hypertrophy that acts via a direct local effect on cardiomyocytes.
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MESH Headings
- Adenylyl Cyclases/metabolism
- Animals
- Aorta/drug effects
- Aorta/pathology
- Blood Pressure
- Blotting, Northern
- COS Cells
- Cyclic GMP/metabolism
- DNA, Complementary/metabolism
- Echocardiography
- Guanylate Cyclase/biosynthesis
- Guanylate Cyclase/chemistry
- Guanylate Cyclase/genetics
- Hypertrophy
- Isoproterenol/pharmacology
- Male
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Myocardium/enzymology
- Myocardium/metabolism
- Peptides/chemistry
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Rats
- Receptors, Atrial Natriuretic Factor/chemistry
- Receptors, Atrial Natriuretic Factor/genetics
- Tissue Distribution
- Transfection
- Transgenes
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Affiliation(s)
- Ahmad Zahabi
- Experimental Cardiovascular Biology Unit, Canadian Institutes for Health Research Multidisciplinary Research Group in Hypertension, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada
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179
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Miura S, Ohno I, Suzuki J, Suzuki K, Okada S, Okuyama A, Nawata J, Ikeda J, Shirato K. Inhibition of matrix metalloproteinases prevents cardiac hypertrophy induced by beta-adrenergic stimulation in rats. J Cardiovasc Pharmacol 2003; 42:174-81. [PMID: 12883319 DOI: 10.1097/00005344-200308000-00004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Insulin-like growth factor (IGF) -I is one of the candidates for cardiac hypertrophy induced by beta-adrenergic stimulation. However, the mechanisms by which the biologic actions of IGF-I are regulated under this condition remain unclear. IGF-I becomes bioavailable for its receptors upon its dissociation from IGF-binding protein (IGFBP) through IGFBP degradation. Because matrix metalloproteinases (MMPs) have been implicated in the degradation of IGFBPs, the authors investigated the role of MMPs in the regulation of the IGF-I action through the degradation of IGFBPs in cardiac hypertrophy induced by beta-adrenergic stimulation. They examined the expression of MMPs in cardiac tissues of rats infused with isoproterenol (3 mg/kg per day), the effect of a MMP inhibitor, SI-27 (5 mg/rat per day), on cardiac hypertrophy, and the expression of IGF-I and IGFBP-3. MMP-1 and -2 activities increased and IGFBP-3 was degraded in heart hypertrophied by isoproterenol. MMP inhibition caused a regression in the myocyte hypertrophy in association with the suppression of both IGF-I protein in myocytes and the degradation of IGFBP-3 protein. These results suggest that the induction of myocyte hypertrophy by isoproterenol is mediated, at least in part, by a modulation of the IGF-I axis.
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Affiliation(s)
- Shoko Miura
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machio, Aoba-ku, Sendai 980-8574, Japan
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180
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Abstract
Circulating angiotensin (Ang) II has well-known endocrine properties in the cardiovasculature. AngII, produced de novo within the heart, has various autocrine and paracrine properties on resident cells expressed via AT(1) receptor-ligand binding. Herein, we review the heart's renin-angiotensin system and its role in connective tissue turnover involving heart valve leaflets and fibrous tissue that appears at sites of injury, such as following myocardial infarction.
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Affiliation(s)
- Yao Sun
- Department of Medicine, Division of Cardiovascular Diseases, University of Tennessee Health Science Center, Rm. 353 Dobbs Research Institute, 951 Court Avenue, Memphis, TN 38163, USA
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181
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Braun M, Simonis G, Birkner K, Pauke B, Strasser RH. Regulation of protein kinase C isozyme and calcineurin expression in isoproterenol induced cardiac hypertrophy. J Cardiovasc Pharmacol 2003; 41:946-54. [PMID: 12775975 DOI: 10.1097/00005344-200306000-00018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Protein kinase C (PKC) and calcineurin are known to play a pivotal role in the development of cardiomyocyte growth. However, its role in Isoproterenol-induced (Iso) cardiac hypertrophy has not been characterized so far and were focus of the current study. After chronic beta-adrenergic stimulation of male Wistar rats with Iso (2mg/kg x day) for 2 and 7 days using osmotic minipumps, we determined a) cardiac PKC-activity, b) the expression of cardiac PKC isozymes (PKC-alpha, PKC-delta and PKC-epsilon) both at the protein and the mRNA-level and c) the expression of calcineurin using Western blot analysis. Iso-treatment for 2 and 7 days results in cardiac hypertrophy with an increase of the heart weight-to-body weight ratio by 36% and 27%. Iso-induced myocardial growth was associated with an enhanced total PKC-activity and a significant increased protein expression of cytosolic PKC-alpha (day 2: +38%; day 7: +43%), PKC-delta (day 2: 85%; day 7: +78%) and PKC-epsilon (day 7: +58%). The protein amount of calcineurin was not significantly altered by Iso compared with sham-operated controls. The increased expression of PKC-alpha, PKC-delta and PKC-epsilon in the cytosol was paralleled by a transcriptional upregulation of the absolute mRNA-levels of these PKC-isozymes as determined by quantitative RT-PCR.
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Affiliation(s)
- Martin Braun
- Department of Cardiology, Medical Clinic II, University of Technology Dresden, Germany.
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182
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Tan LB, Burniston JG, Clark WA, Ng Y, Goldspink DF. Characterization of adrenoceptor involvement in skeletal and cardiac myotoxicity Induced by sympathomimetic agents: toward a new bioassay for beta-blockers. J Cardiovasc Pharmacol 2003; 41:518-25. [PMID: 12658052 DOI: 10.1097/00005344-200304000-00003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Excessive levels of catecholamines have long been known to be cardiotoxic, but less well known are their toxic effects on skeletal muscle. By using an antimyosin monoclonal antibody and quantitative methods to measure the extent of myocyte necrosis, and by employing modulators of adrenoceptors (ARs), including clenbuterol, bupranolol, propranolol, bisoprolol, atenolol, ICI-118551, phenoxybenzamine, prazosin, and yohimbine, the involvement of ARs in isoproterenol-induced myotoxicity was characterized. In the myocardium, the toxic effects were predominantly mediated via the beta(1)-ARs. In the soleus muscle, it was almost solely via the beta(2)-ARs. Myotoxicity was also observed in the myocardium when challenged with the beta(2)-AR agonist clenbuterol. This was found to be mediated via sympathetic presynaptic beta(2)-ARs, leading to enhanced release of norepinephrine. This effect was abolished by prior treatment with reserpine. The skeletal muscle was found to be more sensitive to the myotoxic effects than cardiac muscle at lower doses of beta-AR agonists. These experiments introduce a new way of assaying beta-AR antagonists by classifying them according to their ability to prevent catecholamine-induced myotoxicity. Further research along these lines may deepen understanding of which beta-blockers work best in heart failure therapy.
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Affiliation(s)
- Lip-Bun Tan
- Academic Unit of Molecular Vascular Medicine, University of Leeds, England
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183
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Lara HE, Dorfman M, Venegas M, Luza SM, Luna SL, Mayerhofer A, Guimaraes MA, Rosa E Silva AAM, Ramírez VD. Changes in sympathetic nerve activity of the mammalian ovary during a normal estrous cycle and in polycystic ovary syndrome: Studies on norepinephrine release. Microsc Res Tech 2002; 59:495-502. [PMID: 12467025 DOI: 10.1002/jemt.10229] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although it has been known for many years that the ovary is innervated by catecholaminergic nerve fibers and much experimental evidence has strengthened the notion that catecholamines are physiologically involved in the control of ovarian function, scarce evidence has been presented as to the role of sympathetic activity in ovarian pathologies that affect reproductive function. The purpose of this article is to provide a succinct overview of the findings in this area and discuss them relative to the pathology of polycystic ovary syndrome, the most common ovarian pathology in women during their reproductive years.
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Affiliation(s)
- H E Lara
- Laboratory of Neurobiochemistry, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago-1, Chile.
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184
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Ng Y, Goldspink DF, Burniston JG, Clark WA, Colyer J, Tan LB. Characterisation of isoprenaline myotoxicity on slow-twitch skeletal versus cardiac muscle. Int J Cardiol 2002; 86:299-309. [PMID: 12419570 DOI: 10.1016/s0167-5273(02)00369-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Elevated catecholamines are known to be cardiotoxic, but their potential injurious effects on skeletal muscles are largely unknown. We have investigated whether isoprenaline induces in vivo myocyte necrosis in rat soleus muscle, and characterised the time-course, dose-response, spatial distribution and adrenoceptor involvement of its myotoxicity, in comparison with effects on cardiomyocytes in the same animals. MATERIAL AND METHODS Myocyte necrosis in response to subcutaneous isoprenaline was detected in vivo using a monoclonal anti-myosin antibody. Secondary immunoperoxidase staining (in vitro) facilitated the localisation of the damage and quantitative image analysis. RESULTS Using this sensitive technique we report a novel observation that isoprenaline induces significant myocyte necrosis (5-10%) in the soleus muscle. This toxic damage was initiated at lower doses of isoprenaline than in the myocardium (1 vs. 10 microg kg(-1) s.c.), and peaked earlier (at 12 vs. 18 h post injection). Damage was distributed throughout the soleus muscle, whereas cardiomyocyte necrosis was most marked in left ventricular subendocardium where it was approximately 10 and three times greater than in the subepicardium and atria, respectively. Using selective adrenoceptor (AR) antagonism, we found that isoprenaline myotoxicity was mediated via beta(2)-AR in the soleus and via beta(1)-AR in the myocardium. CONCLUSION The results show that the myopathic effects of isoprenaline are not confined to the heart. The involvement of skeletal muscle with different characteristics and mechanisms may have important implications in elucidating and treating the generalised myopathic processes seen in heart failure patients who have elevated levels of circulating catecholamines.
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Affiliation(s)
- YeeLan Ng
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, 15-21 Webster Street, UK
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185
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Burniston JG, Ng Y, Clark WA, Colyer J, Tan LB, Goldspink DF. Myotoxic effects of clenbuterol in the rat heart and soleus muscle. J Appl Physiol (1985) 2002; 93:1824-32. [PMID: 12381771 DOI: 10.1152/japplphysiol.00139.2002] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Myocyte-specific necrosis in the heart and soleus muscle of adult male Wistar rats was investigated in response to a single subcutaneous injection of the anabolic beta(2)-adrenergic receptor agonist clenbuterol. Necrosis was immunohistochemically detected by administration of a myosin antibody 1 h before the clenbuterol challenge and quantified by using image analysis. Clenbuterol-induced myocyte necrosis occurred against a background of zero damage in control muscles. In the heart, the clenbuterol-induced necrosis was not uniform, being more abundant in the left subendocardium and peaking 2.4 mm from the apex. After position (2.4 mm from the apex), dose (5 mg clenbuterol/kg), and sampling time (12 h) were optimized, maximum cardiomyocyte necrosis was found to be 1.0 +/- 0.2%. In response to the same parameters (i.e., 5 mg of clenbuterol and sampled at 12 h), skeletal myocyte necrosis was 4.4 +/- 0.8% in the soleus. These data show significant myocyte-specific necrosis in the heart and skeletal muscle of the rat. Such irreversible damage in the heart suggests that clenbuterol may be damaging to long-term health.
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MESH Headings
- Adrenergic beta-Agonists/administration & dosage
- Adrenergic beta-Agonists/poisoning
- Animals
- Clenbuterol/administration & dosage
- Clenbuterol/poisoning
- Dose-Response Relationship, Drug
- Heart/drug effects
- Injections, Subcutaneous
- Intubation, Gastrointestinal
- Male
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/pathology
- Myocardium/pathology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/pathology
- Necrosis
- Rats
- Rats, Wistar
- Receptors, Adrenergic, beta/metabolism
- Time Factors
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Affiliation(s)
- Jatin G Burniston
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 2ET, United Kingdom.
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186
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Gao XM, Dilley RJ, Samuel CS, Percy E, Fullerton MJ, Dart AM, Du XJ. Lower risk of postinfarct rupture in mouse heart overexpressing beta 2-adrenergic receptors: importance of collagen content. J Cardiovasc Pharmacol 2002; 40:632-40. [PMID: 12352327 DOI: 10.1097/00005344-200210000-00018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
This paper addresses whether the enhanced left ventricular (LV) contractility and heart rate, seen in transgenic mice overexpressing beta -adrenergic receptor in the heart, might raise the incidence of LV rupture after myocardial infarct. Transgenic and wild-type mice underwent left coronary artery occlusion. Postinfarct deaths that occurred 1-7 days after surgery were analyzed. Hemodynamics, morphologic parameters, and collagen content in the LV were determined. A significantly lower incidence of LV rupture was observed in transgenic than in wild-type mice 3-5 days after myocardial infarct (2.5 versus 19.7%, p < 0.05), despite a similar infarct size between the two groups and better hemodynamic function in transgenic mouse hearts. Morphologic analysis showed a more severe infarct expansion in wild-type versus transgenic mice or in mice dying of rupture versus those that died of acute heart failure. Collagen content was higher in the LV of sham-operated transgenic than wild-type mice (p < 0.01) with both type I and type III collagen elevated. Such difference in collagen content between transgenic and wild-type mice was maintained in noninfarcted and infarcted LV. In conclusion, transgenic mice overexpressing beta -adrenergic receptor had a lower risk of cardiac rupture during the acute phase after infarction despite the markedly enhanced LV contractility and heart rate. As a hyperdynamic function due to beta-adrenergic activation would likely increase the risk of cardiac rupture and infarct expansion, the lack of rupture in this transgenic mouse model suggests that the interstitial collagen level is a more important factor than functional status in the pathogenesis of rupture and infarct expansion.
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Affiliation(s)
- Xiao-Ming Gao
- Baker Medical Research Institute, Melbourne, Victoria, Australia.
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187
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Van Kerckhoven R, Saxena PR, Schoemaker RG. Restored capillary density in spared myocardium of infarcted rats improves ischemic tolerance. J Cardiovasc Pharmacol 2002; 40:370-80. [PMID: 12198323 DOI: 10.1097/00005344-200209000-00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Myocardial infarction (MI)-induced hypertrophy is associated with a decreased capillary density, which may negatively affect ischemic tolerance of the spared myocardium. The current study investigated the effects of moxonidine, a centrally acting sympatholytic, on left ventricular (LV) hypertrophy and capillary density in relation to sensitivity to ischemia in infarcted hearts. Infarcted rats were randomized to receive 3 or 6 mg/kg/d of moxonidine from 1 to 21 days after MI. LV hypertrophy after MI was indicated by increased ventricular to body weight ratio and was significantly inhibited by moxonidine. Histologic analysis revealed that MI-induced concentric hypertrophy of the spared myocardium, as indicated by almost double cross-sectional area of Gomori-stained myocytes, was completely prevented by 6 mg/kg/d of moxonidine. This effect was accompanied by a a restored number of lectin-stained capillaries per tissue area. However, capillary-to-myocyte ratio was similar in all groups. LV dysfunction after MI, measured in isolated perfused hearts, was confirmed by decreased LV systolic pressure and +dP/dtmax and was not affected by moxonidine. Low-flow ischemia, induced by lowering perfusion pressure from 85 to 15 mm Hg for 30 min, resulted in a further reduction of cardiac perfusion compared with sham rats, which was normalized with 6 mg/kg/d of moxonidine. Ischemic sensitivity in MI hearts, as reflected by increased maximal coronary flow during reperfusion, was reduced with moxonidine. This was further supported by substantially lower purines and lactate concentrations in the coronary effluent during ischemia. These results indicate that moxonidine-induced prevention of hypertrophy may preserve capillary density without affecting capillary number, thereby improving ischemic tolerance of the spared myocardium.
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Affiliation(s)
- Roeland Van Kerckhoven
- Deparment of Pharacology, Faculty of Medicine and Health Sciences, Erasmus University, Rotterdam, The Netherlands.
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188
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Ozaki M, Kawashima S, Yamashita T, Hirase T, Ohashi Y, Inoue N, Hirata KI, Yokoyama M. Overexpression of endothelial nitric oxide synthase attenuates cardiac hypertrophy induced by chronic isoproterenol infusion. Circ J 2002; 66:851-6. [PMID: 12224825 DOI: 10.1253/circj.66.851] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Endogenous nitric oxide (NO) inhibits the contractile response to beta-adrenergic stimulation, but its effect on cardiac hypertrophy mediated by beta-adrenoceptors remains unclear. The present study was designed to determine whether overproduction of endothelial NO synthase (eNOS) could inhibit cardiac hypertrophy induced by chronic isoproterenol (ISO) infusion (30mg/kg per day) using eNOS overexpressing (eNOS-Tg) mice and wild-type (WT) mice. In a separate group, WT mice were treated with ISO and hydralazine to decrease blood pressure to the same levels in eNOS-Tg mice. The eNOS expression, NOS activity, and cGMP levels in the heart were remarkably higher in eNOS-Tg mice than in WT mice. ISO increased both heart weight and the heart/body weight ratio, which were significantly attenuated in eNOS-Tg mice compared with WT or hydralazine-treated WT mice. Histological examination revealed that the extent of fibrosis was not significantly different among the 3 groups, and that the increase in myocyte size was more than 10% lower in eNOS-Tg than in the other groups. In addition, up-regulated expression of atrial natriuretic peptide mRNA associated with cardiac hypertrophy was significantly inhibited in eNOS-Tg mice during ISO infusion. These results indicate that endogenous NO might act as a negative modulator for the hypertrophic response to beta-adrenergic stimulation.
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Affiliation(s)
- Masanori Ozaki
- Department of Internal Medicine, Kobe University Graduate School of Medicine, Japan
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189
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Van Kerckhoven R, Lankhuizen I, van Veghel R, Saxena PR, Schoemaker RG. Chronic vasopressin V(1A) but not V(2) receptor antagonism prevents heart failure in chronically infarcted rats. Eur J Pharmacol 2002; 449:135-41. [PMID: 12163117 DOI: 10.1016/s0014-2999(02)01972-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Evidence is increasing that therapeutic modulation of neurohormonal activation with vasopressin receptor antagonists via V(1A) and V(2) receptors may favourably affect prognosis of heart failure. This study was designed to compare in vivo hemodynamic effects of early treatment (1-21 days after infarction) with a V(1A) (SR-49059 or ((2S)1-[(2R3S)-5-chloro-3-(2-chlorophenyl)-1-(3,4-dimethoxybenzene-sulfonyl)-3-hydroxy-2,3-dihydro-1H-indole-2-carbonyl]-pyrrolidine-2-carboxamide); 0.3 mg/kg/day) and a V(2) (SR-121463B or (1-[4-(N-tert-Butylcarbamoyl)-2-methoxybenzene sulfonyl]-5-ethoxy-3-spiro-[4-(2-morpholinoethyoxy)-cyclo-hexane]indol-2one,furmate; 0.5 mg/kg/day) receptor antagonist in myocardial infarcted rats, chronically instrumented for hemodynamic measurements. Left ventricular dysfunction in conscious myocardial infarcted rats, which was evidenced by a significantly decreased cardiac output (myocardial infarction: 70+/-3 vs. sham: 81 +/- 3 ml/min) and stroke volume (myocardial infarction: 190 +/- 10 vs. sham: 221 +/- 7 microl), was restored by the vasopressin V(1A) (81+/-2 ml and 224 +/- 5 microl, respectively) but not V(2) receptor antagonist. Improved cardiac output with the vasopressin V(1A) receptor antagonist resulted from an increased stroke volume at a reduced myocardial infarction induced tachycardia. In addition to the hemodynamic measurements, left ventricular hypertrophy and capillary density were determined, histologically measured as the cross-sectional area of Gomori-stained myocytes and Lectin-stained capillaries per tissue area, respectively. The observed left ventricular concentric hypertrophy (myocardial infarction: 525 +/- 38 vs. sham: 347 +/- 28 microm(2); P < 0.05) and reduced capillary density (myocardial infarction: 2068 +/- 162 vs. sham: 2800 +/- 250 number/mm(2); P<0.05) in the spared myocardium of myocardial infarcted rats, remained unaffected by the vasopressin V(1A) or V(2) receptor antagonist. Thus, chronic vasopressin V(1A) but not V(2) receptor blockade prevents heart failure in 3-week-old infarcted rats. Moreover, the improved cardiac function could not attributed to changes in left ventricular hypertrophy and/or capillary density.
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Affiliation(s)
- Roeland Van Kerckhoven
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands. ,eur.nl
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190
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Ocaranza MP, Díaz-Araya G, Chiong M, Muñoz D, Riveros JP, Ebensperger R, Sabat S, Irarrázaval P, Jalil JE, Lavandero S. Isoproterenol and angiotensin I-converting enzyme in lung, left ventricle, and plasma during myocardial hypertrophy and fibrosis. J Cardiovasc Pharmacol 2002; 40:246-54. [PMID: 12131554 DOI: 10.1097/00005344-200208000-00010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study investigated whether long-term administration of isoproterenol (ISO) induces differential expression of angiotensin-converting enzyme (ACE) in lung, plasma, and left ventricle (LV) during development of left ventricular hypertrophy (LVH) and myocardial fibrosis. Male Sprague-Dawley rats (n = 7-9 per group) were treated with isoproterenol (ISO) 5 mg/kg per day for 10 days or saline and examined at 1, 15, and 33 days after the last injection. ISO stimulated the development of left ventricular hypertrophy (LVH); relative LV weight (mg LV 100/body weight), LV protein content, and LV beta-myosin heavy chain levels increased at day 1. LVH regressed at days 15 and 33. ISO also increased myocardial fibrosis (assessed by hydroxyproline content and morphometry) at days 15 and 33. There no were changes in arterial blood pressure. Long-term beta-adrenergic stimulation with ISO increased ACE expression in lung, LV, and plasma during development of LVH and myocardial fibrosis. However, time courses were markedly different. ISO stimulated a sustained increase in lung and plasma ACE activities, whereas ISO induced a high LV ACE. Plasma ACE activity paralleled lung ACE activity. LV ACE activity correlated with ACE mRNA levels and paralleled development of LVH. Our data suggest long-term beta-adrenergic stimulation induced a differential temporal expression of LV, lung, and plasma ACE in rat during development of LVH and myocardial fibrosis.
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Affiliation(s)
- María Paz Ocaranza
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Olivos 1007, Santiago, Chile
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191
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Köhnlein T, Welte T, Tan LB, Elliott MW. Central sleep apnoea syndrome in patients with chronic heart disease: a critical review of the current literature. Thorax 2002; 57:547-54. [PMID: 12037232 PMCID: PMC1746358 DOI: 10.1136/thorax.57.6.547] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The prevalence, prognosis, clinical presentation, pathophysiology, diagnosis, and treatment of the central sleep apnoea syndrome (CSAS) are reviewed and its relationship with congestive heart failure (CHF) is discussed. Adequately powered trials are needed with survival and health status as end points to establish whether correction of sleep related breathing abnormalities improves the outcome in patients with CHF.
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Affiliation(s)
- T Köhnlein
- Otto-von-Guericke-Universität Magdeburg, Department for Pulmonary and Intensive Care Medicine, Germany
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192
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Bua EA, McKiernan SH, Wanagat J, McKenzie D, Aiken JM. Mitochondrial abnormalities are more frequent in muscles undergoing sarcopenia. J Appl Physiol (1985) 2002; 92:2617-24. [PMID: 12015381 DOI: 10.1152/japplphysiol.01102.2001] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The hypothesis that the accumulation of electron transport system (ETS) abnormalities and sarcopenia are linked was investigated. Vastus lateralis, soleus, and adductor longus muscles were studied in 5-, 18-, and 36-mo-old male Fischer 344 x Brown Norway F(1) hybrid rats. A significant decrease in soleus and vastus lateralis muscle mass was observed with age. Adductor longus was resistant to muscle mass loss. Multiple serial sections were analyzed for the activities of cytochrome-c oxidase (COX) and succinate dehydrogenase (SDH). The number of fibers exhibiting a COX(-)/SDH(++) phenotype increased with age in both vastus lateralis and soleus muscles. No ETS-abnormal fibers were identified in adductor longus at any age. Cross-sectional area of ETS-abnormal fibers decreased in the abnormal region (region displaying COX(-)/SDH(++) phenotype), whereas control fibers did not. The vastus lateralis muscle, which undergoes a high degree of sarcopenia, exhibited more ETS abnormalities and associated fiber loss than the soleus and adductor longus muscles, which are more resistant to sarcopenia, suggesting a direct association between ETS abnormalities and fiber loss.
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MESH Headings
- Anatomy, Cross-Sectional
- Animals
- Body Weight
- Electron Transport
- Electron Transport Complex IV/metabolism
- Female
- Male
- Mitochondria, Muscle/metabolism
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/ultrastructure
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/ultrastructure
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Atrophy/metabolism
- Muscular Atrophy/pathology
- Organ Size
- Rats
- Rats, Inbred BN
- Rats, Inbred F344
- Succinate Dehydrogenase/metabolism
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Affiliation(s)
- Entela A Bua
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA
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193
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Parr T, Sensky PL, Bardsley RG, Buttery PJ. Calpastatin expression in porcine cardiac and skeletal muscle and partial gene structure. Arch Biochem Biophys 2001; 395:1-13. [PMID: 11673859 DOI: 10.1006/abbi.2001.2546] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The expression in porcine skeletal and cardiac muscle of calpastatin, the specific endogenous inhibitor of the calpain proteolytic system, was examined 16 h after a single dose of a specific beta(2)-agonist. Immunoblotting of extracts indicated that treatment increased skeletal calpastatin 135-kDa band intensity (P < 0.01), while in cardiac combined 145- and 135-kDa band intensity decreased (P < 0.05). Treatment increased skeletal (P < 0.01) but not cardiac calpastatin mRNA steady-state levels. Three types of cardiac calpastatin mRNA transcripts were identified by 5'-RACE. Types I and II encoded a putative XL region that originated either from exon 1x(A) or exon 1x(B), arranged in tandem. Type III predominated in skeletal muscle and originated from exon 1u, which was located 40-50 kb 3' to exons 1x(A) and 1x(B). The region 5' to exon 1u may act as an independent promoter regulated by a cAMP-dependent mechanisms, thereby explaining the differential response of calpastatin to adrenergic stimulation in cardiac and skeletal muscle.
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Affiliation(s)
- T Parr
- Division of Nutritional Biochemistry, University of Nottingham, Loughborough, Leicestershire, LE12 5RD, United Kingdom.
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194
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Ohta T, Hasebe N, Tsuji S, Jin YT, Kido S, Natori S, Sato M, Kikuchi K. Effects of angiotensin converting enzyme inhibitor and angiotensin II type 1 receptor blocker on cardiac dysfunction induced by isoproterenol in dogs. J Cardiovasc Pharmacol 2001; 38 Suppl 1:S63-7. [PMID: 11811362 DOI: 10.1097/00005344-200110001-00014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We examined whether angiotensin converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor blockers (ARB) prevent isoproterenol (ISO)-induced left ventricular (LV) dysfunction in dogs. The effects of a large dose of ISO, 1 microg/kg/min, 3 h infusion, were investigated in three groups with simultaneous infusion of an ACE inhibitor (quinaprilat), ARB (candesartan) or saline. ISO infusion significantly decreased LV dP/dt, LV ejection fraction and LV fractional shortening, and significantly increased tau, the time constant of isovolume relaxation of LV, and LV end diastolic pressure. All of these changes were significantly attenuated in both the ACE inhibitor and ARB groups, especially in the ARB group. Serum levels of creatinin kinase isoform MB, lactate dehydrogenase and lipid peroxide were significantly increased by ISO. However, the increases in these markers of myocardial damage were significantly diminished by simultaneous infusion of an ACE inhibitor or ARB, especially by ARB. In conclusion, an ACE inhibitor and ARB prevent LV systolic and diastolic dysfunction as well as myocardial damage induced by excess beta-adrenergic stimulation.
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Affiliation(s)
- T Ohta
- The First Department of Internal Medicine, Asahikawa Medical College, Hokkaido, Japan
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195
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Morisco C, Zebrowski DC, Vatner DE, Vatner SF, Sadoshima J. Beta-adrenergic cardiac hypertrophy is mediated primarily by the beta(1)-subtype in the rat heart. J Mol Cell Cardiol 2001; 33:561-73. [PMID: 11181023 DOI: 10.1006/jmcc.2000.1332] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Myocardial beta-adrenergic receptors (beta -ARs) consist of beta(1)- and beta(2)-subtypes, which mediate distinct signaling mechanisms. We examined which beta-AR subtype mediates cardiac hypertrophy. The beta(2)-subtype is predominant in neonatal rat cardiac myocytes (beta(1), 36%vbeta(2), 64%), while the beta(1)-subtype predominates in the adult rat heart (59%v 41%). Stimulation of cultured cardiac myocytes in vitro with isoproterenol (ISO), an agonist for beta(1)- and beta(2)-ARs, caused hypertrophy of myocytes along with increases in transcription of atrial natriuretic factor (ANF) and actin reorganization. All of these ISO-mediated myocyte responses in vitro were inhibited by a beta(1)-AR antagonist, betaxolol, but not by a beta(2)-AR antagonist, ICI 118551. Pertussis toxin failed to affect ISO-induced increases in total protein/DNA content and ANF transcription in vitro. ISO increased LV weight/body weight and ANF transcription in the adult rat in vivo, which were also inhibited by betaxolol but not by ICI 118551. These results suggest that beta -AR stimulated hypertrophy is mediated by the beta(1)-subtype and by a pertussis toxin-insensitive mechanism
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MESH Headings
- Adrenergic beta-1 Receptor Antagonists
- Adrenergic beta-2 Receptor Antagonists
- Adrenergic beta-Agonists/pharmacology
- Animals
- Animals, Newborn
- Atrial Natriuretic Factor/metabolism
- Cardiomegaly/metabolism
- Cell Size
- Cells, Cultured
- Heart
- Heart Ventricles/cytology
- Heart Ventricles/metabolism
- Isoproterenol/pharmacology
- Proteins/metabolism
- Rats
- Rats, Wistar
- Receptors, Adrenergic, beta-1/biosynthesis
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/biosynthesis
- Receptors, Adrenergic, beta-2/metabolism
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Affiliation(s)
- C Morisco
- Cardiovascular Research Institute and Department of Medicine, University of Medicine and Dentistry of New Jersey, Hackensack, NJ, USA
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196
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Wanagat J, Cao Z, Pathare P, Aiken JM. Mitochondrial DNA deletion mutations colocalize with segmental electron transport system abnormalities, muscle fiber atrophy, fiber splitting, and oxidative damage in sarcopenia. FASEB J 2001; 15:322-32. [PMID: 11156948 DOI: 10.1096/fj.00-0320com] [Citation(s) in RCA: 306] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The in vivo cellular impact of age-associated mitochondrial DNA mutations is unknown. We hypothesized that mitochondrial DNA deletion mutations contribute to the fiber atrophy and loss that cause sarcopenia, the age-related decline of muscle mass and function. We examined 82,713 rectus femoris muscle fibers from Fischer 344 x Brown Norway F1 hybrid rats of ages 5, 18, and 38 months through 1000 microns by serial cryosectioning and histochemical staining for cytochrome c oxidase and succinate dehydrogenase. Between 5 and 38 months of age, the rectus femoris muscle in the hybrid rat demonstrated a 33% decrease in mass concomitant with a 30% decrease in total fibers at the muscle mid-belly. We observed significant increases in the number of mitochondrial abnormalities with age from 289 +/- 8 ETS abnormal fibers in the entire 5-month-old rectus femoris to 1094 +/- 126 in the 38-month-old as calculated from the volume density of these abnormalities. Segmental mitochondrial abnormalities contained mitochondrial DNA deletion mutations as revealed by laser capture microdissection and whole mitochondrial genome amplification. Muscle fibers harboring mitochondrial deletions often displayed atrophy, splitting and increased steady-state levels of oxidative nucleic damage. These data suggest a causal role for age-associated mitochondrial DNA deletion mutations in sarcopenia.
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MESH Headings
- Aging
- Animals
- Atrophy
- Base Sequence
- DNA Damage
- DNA, Mitochondrial/genetics
- Electron Transport
- Electron Transport Complex IV/metabolism
- Hybridization, Genetic
- Male
- Mitochondria, Muscle/genetics
- Mitochondria, Muscle/metabolism
- Muscle Development
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/growth & development
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Diseases/genetics
- Muscular Diseases/metabolism
- Muscular Diseases/pathology
- Rats
- Rats, Inbred BN
- Rats, Inbred F344
- Sequence Deletion
- Succinate Dehydrogenase/metabolism
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Affiliation(s)
- J Wanagat
- Medical Scientist Training Program, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA
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197
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Jain M, Lim CC, Nagata K, Davis VM, Milstone DS, Liao R, Mortensen RM. Targeted inactivation of Galpha(i) does not alter cardiac function or beta-adrenergic sensitivity. Am J Physiol Heart Circ Physiol 2001; 280:H569-75. [PMID: 11158953 DOI: 10.1152/ajpheart.2001.280.2.h569] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inhibitory Galpha(i) protein increases in the myocardium during hypertrophy and has been associated with beta-adrenergic receptor (beta-AR) desensitization, contractile dysfunction, and progression of cardiac disease. The role of Galpha(i) proteins in mediating basal cardiac function and beta-AR response in nonpathological myocardium, however, is uncertain. Transgenic mice with targeted inactivation of Galpha(i2) or Galpha(i3) were examined for in vivo cardiac function with the use of conscious echocardiography and for ex vivo cardiac response to inotropic stimulation with the use of Langendorff blood-perfused isolated hearts and adult ventricular cardiomyocytes. Echocardiography revealed that percent fractional shortening and heart rate were similar among wild-type, Galpha(i2)-null, and Galpha(i3)-null mice. Comparable baseline diastolic and contractile performance was also observed in isolated hearts and isolated ventricular myocytes from wild-type mice and mice lacking Galpha(i) proteins. Isoproterenol infusion enhanced diastolic and contractile performance to a similar degree in wild-type, Galpha(i2)-null, and Galpha(i3)-null mice. These data demonstrate no observable role for inhibitory G proteins in mediating basal cardiac function or sensitivity to beta-AR stimulation in nonpathological myocardium.
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Affiliation(s)
- M Jain
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts 02115, USA
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198
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Weber KT, Sun Y. Recruitable ACE and tissue repair in the infarcted heart. J Renin Angiotensin Aldosterone Syst 2000; 1:295-303. [PMID: 11967815 DOI: 10.3317/jraas.2000.058] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Constitutive angiotensin-converting enzyme (ACE) is bound to endothelial cells where it serves to regulate circulating concentrations of angiotensin II (Ang II) that normally contribute to circulatory homeostasis. Recruitable ACE, bound to macrophage and myofibroblast cell membrane, regulates local concentrations of Ang II involved in tissue repair. De novo generation of Ang II modulates expression of TGF-beta1 whose autocrine/paracrine properties regulate collagen turnover at sites of fibrous tissue formation that appear in response to various forms of injury in diverse tissues. Persistent myofibroblasts and their ACE activity at the infarct site contribute to a sustained metabolic activity that can account for a progressive fibrosis at, and remote to, sites of myocardial infarction. Activation of the circulating renin-angiotensin-aldosterone system with sustained elevations in plasma Ang II and aldosterone induce a pro-inflammatory vascular phenotype of small arteries and arterioles. This further promotes the appearance of recruitable ACE bound to macrophages and myofibroblasts involved in vascular remodelling. Locally produced Ang II from these vascular sites leads to perivascular fibrosis of intramural coronary vasculature of non-infarcted myocardium. At these sites, remote to the infarct, such adverse structural remodelling by fibrous tissue eventuates in ICM, a major aetiologic factor involved in the appearance of chronic cardiac failure and contributes to its progressive nature.
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199
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Tipnis UR, He GY, Li S, Campbell G, Boor PJ. Attenuation of isoproterenol-mediated myocardial injury in rat by an inhibitor of polyamine synthesis. Cardiovasc Pathol 2000; 9:273-80. [PMID: 11064274 DOI: 10.1016/s1054-8807(00)00038-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE Ornithine decarboxylase (ODC) is an initial rate-limiting enzyme in the synthesis of polyamines (putrescine, spermidine, and spermine) that play a role in cell growth and differentiation. Recent studies have shown that spermidine and spermine cause injury to a variety of cells including myocytes in vitro. In this investigation, we used alpha-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ODC activity and polyamine synthesis to test the hypothesis that polyamines contribute to myocardial injury in rat. METHODS Male Sprague Dawley rats were treated with (i) saline (0.2 ml/day, s.c.), (ii) isoproterenol (ISO) (5 mg/kg/day for 8 days, s.c.) to produce necrotizing myocardial injury, or with (iii) DFMO + ISO. DFMO was started 2 days before the initiation of ISO and both ISO and DFMO were continued until the end of the experimental period. Myocardial injury was assessed by determining the increased release of creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) into the plasma, and by morphometric analysis of the lesion area in heart sections stained with Gomori trichrome. RESULTS ISO induced the release of CPK and LDH by 6 hr and 24 hr, respectively, and produced subendocardial necrosis, which was both acute and resolving following 8 days of ISO. DFMO treatment inhibited ISO-induced increases in (i) ODC activity and putrescine and spermidine levels in heart, (ii) CPK and LDH activity in plasma, and (iii) the area of subendocardial lesions. CONCLUSIONS These observations suggest that polyamines are one of the intracellular factors that contribute to ISO-mediated cardiac injury in the rat.
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Affiliation(s)
- U R Tipnis
- Department of Pathology, The University of Texas, Medical Branch, Galveston, TX 77555-0609, USA
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200
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Abstract
The role of transforming growth factor-beta(1) (TGF-beta(1)) in the production and deposition of collagens and in the induction of gene expression in the myocardium in relation to the development of myocardial fibrosis will be discussed. Very low expression of TGF-beta(1) and collagen type I and III mRNA is seen in the normal rat heart. Both expressions are markedly increased in the infarcted heart and the levels of TGF-beta(1) mRNA precedes increases in mRNA levels for extracellular matrix (ECM) proteins, suggesting a possible role of TGF-beta(1) in remodeling processes in the myocardium. The TGF-beta(1) expression is normally only transient since continuous TGF-beta(1) overexpression seems to promote nonadaptive cardiac hypertrophy and myocardial fibrosis. In vitro, TGF-beta(1) induces an increase in collagen production and secretion and enhances the abundance of mRNA levels for collagen type I and III in rat cardiac fibroblasts in culture. TGF-beta(1) also stimulates in vivo the expression of ECM proteins and in vivo gene transfer of TGF-beta(1) can induce myocardial fibrosis. Increased myocardial TGF-beta(1) and ECM protein mRNA are found in myocardial fibrosis induced by angiotensin II infusion, by noradrenaline treatment, by isoprenaline infusion, and by long-term blockade of NO synthesis. In vivo antagonism of TGF-beta(1) by neutralizing anti-TGF-beta(1) antibodies or by proteoglycans prevents the increase in gene expression of ECM proteins and inhibits myocardial fibrosis, suggesting that the increases in matrix protein production and fibrosis are mediated by TGF-beta(1).
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Affiliation(s)
- P J Lijnen
- Hypertension and Cardiovascular Rehabilitation Unit, University of Leuven (K.U.Leuven), Leuven, Belgium
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