transforming-growth-factor-beta and Cardiac-Output--Low

Transforming growth factor (TGF-beta) is a multifunctional peptide growth factor that has an important role in the regulation of cell growth, differentiation, and repair in a variety of tissues. In mammals, the cytokine has three isoforms, TGF-beta1, TGF-beta2, and TGF-beta3. TGF- beta1 is up-regulated by Ang II and induction of TGF-beta1 causes cardiac fibrosis. The stimulus that triggers the expression of TGF-beta1 may be repeated causing continual injury, which is associated with an increase in the activity of Ang II in heart tissue. The interplay between Ang II and TGF-beta1 causes continued activation that may result in chronic hypertension and progressive myocardial fibrosis, leading to heart failure. The regulation of TGF-beta1 secretion and action involves complex transcriptional events. Overproduction of TGF-beta1 underlies tissue fibrosis. Understanding the actions and signaling transduction of TGF-beta could lead to the development of therapeutic options that may be effective in inhibiting myocardial fibrosis triggered by TGF-beta1 in heart failure.

Topics: Angiotensin II; Animals; Cardiac Output, Low; Chronic Disease; Disease Progression; Heart Diseases; Humans; Myocardium; Signal Transduction; Transforming Growth Factor beta; Ventricular Remodeling

Angiotensin II blockade and spironolactone effectively reduces proteinuria in humans. To clarify the mechanisms of the beneficial effect of blockade of both aldosterone and angiotensin II, we associated the aldosterone antagonist eplerenone to an angiotensin-converting enzyme inhibitor (ACEI) and examined the effect on renal transforming growth factor (TGF)-beta expression and oxidative stress by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in the Dahl salt-sensitive rat with heart failure (DSHF).. Dahl salt-resistant control rats and DSHF rats were fed with 8% NaCl diet and at 11 weeks the DSHF rats were treated with vehicle, eplerenone (Epl), trandolapril or a combination of both drugs for 7 weeks.. DSHF rats showed increased NADPH oxidase and decreased superoxide dismutase (SOD) resulting in increased oxidative stress. ACEI and Epl reduced NADPH oxidase showing an additive effect in their combination; ACEI increased manganese SOD (MnSOD) and Epl increased MnSOD, copper-zinc SOD and catalase, resulting in the lowest levels of oxidative stress with the combination therapy. Glomerulosclerosis and proteinuria were increased in the DSHF rats, and Epl suppressed them more effectively than ACEI to levels not different from the combination of both, showing a positive correlation with NADPH oxidase expression and TGF-beta. Renal TGF-beta was specifically suppressed with Epl. The association of Epl to ACEI is beneficial due to further reduction of NADPH oxidase and specific inhibition of TGF-beta resulting in improvement of renal damage.

Topics: Aldosterone; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Cardiac Output, Low; Drug Synergism; Eplerenone; Hypertension; Indoles; Kidney; Male; Mineralocorticoid Receptor Antagonists; NADPH Oxidases; Oxidative Stress; Rats; Rats, Inbred Dahl; Reactive Oxygen Species; Sodium-Potassium-Exchanging ATPase; Spironolactone; Superoxide Dismutase; Transforming Growth Factor beta

Tissue kallikrein is a serine proteinase that generates the vasoactive kinin peptide, which produces vasodilatory, angiogenic, and antiapoptotic effects. In this study, we investigated the effect of a stable supply of kallikrein and kinin on ventricular remodeling and blood vessel growth in rats after myocardial infarction.. At 1 week after coronary artery ligation, tissue kallikrein or kinin was infused through a minipump for 4 weeks. At 5 weeks after myocardial infarction, kallikrein and kinin infusion significantly improved cardiac contractility and reduced diastolic dysfunction without affecting systolic blood pressure. Kallikrein and kinin infusion significantly increased capillary density in the noninfarcted region. Kallikrein and kinin infusion also reduced heart weight/body weight ratio, cardiomyocyte size, and atrial natriuretic peptide and brain natriuretic peptide expression in the noninfarcted area. Moreover, kallikrein and kinin infusion inhibited interstitial collagen deposition, collagen fraction volume, and collagen I and collagen III mRNA levels, transforming growth factor (TGF)-beta1 and plasminogen activator inhibitor-1 expression, and Smad2 phosphorylation. The effects of kallikrein and kinin on cardiac remodeling were associated with increased nitric oxide levels and reduced NADPH oxidase expression and activity, superoxide formation, and malondialdehyde levels. Furthermore, in cultured cardiac fibroblasts, kinin inhibited angiotensin II-stimulated TGF-beta1 production, and the effect was blocked by icatibant.. These results indicate that a subdepressor dose of kallikrein or kinin can restore impaired cardiac function in rats with postinfarction heart failure by inhibiting hypertrophy and fibrosis and promoting angiogenesis through increased nitric oxide formation and suppression of oxidative stress and TGF-beta1 expression.

Topics: Animals; Capillaries; Cardiac Output, Low; Cardiomegaly; Cells, Cultured; Collagen; Coronary Vessels; Dose-Response Relationship, Drug; Fibroblasts; Heart; Infusion Pumps; Kinins; Myocardial Contraction; Myocardial Infarction; Myocardium; Neovascularization, Physiologic; Nitrates; Nitrites; Oxidative Stress; Rats; Rats, Sprague-Dawley; Rats, Wistar; Salvage Therapy; Tissue Kallikreins; Transforming Growth Factor beta; Ventricular Remodeling

We and other investigators have reported that short- and long-term treatment with adrenomedullin has beneficial effects in heart failure. This study examined the effects of long-term treatment with a vasopeptidase inhibitor plus adrenomedullin in a model of heart failure in rats and assessed potential mechanisms of action.. Dahl salt-sensitive rats aged 11 weeks were randomly divided into three groups: an omapatrilat group, an omapatrilat plus adrenomedullin group, and an untreated group. The effects of these treatments were evaluated after 7 weeks of treatment.. Omapatrilat monotherapy significantly improved left ventricular weight (LVW), blood pressure (BP), and central hemodynamics as compared with the untreated group. Omapatrilat decreased the gene expression levels of adrenomedullin and atrial natriuretic peptide (ANP) in the left ventricle. In addition, omapatrilat decreased mRNA levels of transforming growth factor-beta (TGF-beta), collagen I, collagen III, plasminogen activator inhibitor-1 (PAI-1), and intercellular adhesion molecule-1 (ICAM-1) in the left ventricle, and omapatrilat decreased perifibrosis score and myocyte area histologically. Omapatrilat plus adrenomedullin further improved LVW, central hemodynamics, and mRNA expression of TGF-beta, collagen I, collagen III, PAI-1, and ICAM-1 without changing BP. Omapatrilat plus adrenomedullin further reduced mRNA levels of ANP and adrenomedullin without altering levels of ANP or adrenomedullin in plasma. Interestingly, omapatrilat slightly decreased mRNA levels of subunits of NADPH oxidase, whereas omapatrilat plus adrenomedullin further decreased these variables.. Our results suggest that combined treatment with adrenomedullin and omapatrilat may be a new strategy for the management of heart failure, acting partly by inhibition of the extracellular matrix gene, adhesion molecule, antifibrinolysis, and oxidative stress production.

Topics: Adrenomedullin; Animals; Antihypertensive Agents; Atrial Natriuretic Factor; Blood Pressure; Cardiac Output, Low; Collagen; Disease Progression; Drug Therapy, Combination; Gene Expression Regulation; Heart Ventricles; Intercellular Adhesion Molecule-1; Male; NADPH Oxidases; Plasminogen Activator Inhibitor 1; Pyridines; Rats; Rats, Inbred Dahl; RNA, Messenger; Thiazepines; Transforming Growth Factor beta

Inflammation may play an important role in the pathogenesis of cardiac fibrosis in heart failure (HF) after myocardial infarction (MI). N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a naturally occurring antifibrotic peptide whose plasma concentration is increased 4- to 5-fold by angiotensin-converting enzyme inhibitors. We tested the hypothesis that in rats with HF after MI, Ac-SDKP acts as an anti-inflammatory cytokine, preventing and also reversing cardiac fibrosis in the noninfarcted area (reactive fibrosis), and thus affording functional improvement. We found that Ac-SDKP significantly decreased total collagen content in the prevention group from 23.7+/-0.9 to 15.0+/-0.7 microg/mg and in the reversal group from 22.6+/-2.2 to 14.4+/-1.6 (P<0.01). Interstitial collagen volume fraction and perivascular collagen were likewise significantly reduced. We also found that infiltrating macrophages were reduced from 264.7+/-8.1 to 170.2+/-9.2/mm2, P<0.001 (prevention), and from 257.5+/-9.1 to 153.1+/-8.5 mm2, P<0.001 (reversal), while transforming growth factor (TGF)-beta-positive cells were decreased from 195.6+/-8.4 to 129.6+/-5.7/mm2, P<0.01 (prevention), and from 195.6+/-8.4 to 130.7+/-10.8/mm2, P<0.01 (reversal). Ac-SDKP did not alter either blood pressure or left ventricular hypertrophy (LVH); however, it depressed systolic cardiac function in the prevention study while having no significant effect in the reversal group. We concluded that Ac-SDKP has an anti-inflammatory effect in HF that may contribute to its antifibrotic effect; however, this decrease in fibrosis without changes in LVH was not accompanied by an improvement in cardiac function.

Topics: Animals; Anti-Inflammatory Agents; Blood Pressure; Cardiac Output, Low; Cell Movement; Collagen; Fibrosis; Heart; Heart Rate; Inflammation; Macrophages; Male; Myocardial Infarction; Myocardium; Oligopeptides; Rats; Rats, Inbred Lew; Transforming Growth Factor beta

The transforming-growth-factor-beta-activated kinase TAK1 is a member of the mitogen-activated protein kinase kinase kinase family, which couples extracellular stimuli to gene transcription. The in vivo function of TAK1 is not understood. Here, we investigated the potential involvement of TAK1 in cardiac hypertrophy. In adult mouse myocardium, TAK1 kinase activity was upregulated 7 days after aortic banding, a mechanical load that induces hypertrophy and expression of transforming growth factor beta. An activating mutation of TAK1 expressed in myocardium of transgenic mice was sufficient to produce p38 mitogen-activated protein kinase phosphorylation in vivo, cardiac hypertrophy, interstitial fibrosis, severe myocardial dysfunction, 'fetal' gene induction, apoptosis and early lethality. Thus, TAK1 activity is induced as a delayed response to mechanical stress, and can suffice to elicit myocardial hypertrophy and fulminant heart failure.

Topics: Activating Transcription Factor 6; Animals; Aorta; Blood Pressure; Cardiac Output, Low; Cardiomegaly; Diastole; DNA-Binding Proteins; Down-Regulation; Male; MAP Kinase Kinase Kinases; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mitogen-Activated Protein Kinases; Nuclear Proteins; p38 Mitogen-Activated Protein Kinases; Serum Response Factor; Signal Transduction; Systole; Transcription Factors; Transforming Growth Factor beta