Eicosapentaenoic acid prevents atrial fibrillation associated with heart failure in a rabbit model

2011 ◽  
Vol 300 (5) ◽  
pp. H1814-H1821 ◽  
Author(s):  
Kazuhisa Kitamura ◽  
Rei Shibata ◽  
Yukiomi Tsuji ◽  
Masayuki Shimano ◽  
Yasuya Inden ◽  
...  
Keyword(s):  
Heart Failure ◽  
Atrial Fibrillation ◽  
Eicosapentaenoic Acid ◽  
Transforming Growth Factor ◽  
Rabbit Model ◽  
Transforming Growth Factor Β1 ◽  
Atrial Remodeling ◽  
Atrial Fibrosis ◽  
Erk Phosphorylation ◽  
Tgf Β1

Atrial fibrillation (AF) is associated with morbidity and mortality of heart failure. Eicosapentaenoic acid (EPA), which is contained in fish oil, was shown to reduce the risk of cardiovascular diseases. We investigated the effects of EPA on AF associated with heart failure in a rabbit model. Rabbits were subjected to ventricular tachypacing (VTP) for 4 wk with or without EPA treatment. Continuous VTP induced heart failure status in these rabbits. The duration of AF (DAF) induced by burst pacing was analyzed by electrophysiological studies. VTP resulted in increased DAF following burst pacing. EPA treatment attenuated increased DAF. Atrial fibrosis increased in response to VTP, accompanied by extracellular signal-regulated kinase (ERK) phosphorylation and transforming growth factor-β1 (TGF-β1) expression in the atrium. Treatment with EPA attenuated atrial fibrosis, ERK phosphorylation, and TGF-β1 expression in response to VTP. EPA treatment increased adiponectin as an anti-inflammatory adipokine and decreased tumor necrosis factor-α as a proinflammatory adipokine in the atrium and epicardial adipose tissues. EPA attenuated VTP-induced AF promotion and atrial remodeling, which was accompanied by modulating the profiles of adipokine production from epicardial adipose tissue. EPA may be useful for prevention and treatment of AF associated with heart failure.

scholarly journals A Review of the Molecular Mechanisms Underlying Cardiac Fibrosis and Atrial Fibrillation

2021 ◽  
Vol 10 (19) ◽  
pp. 4430
Author(s):  
Grażyna Sygitowicz ◽  
Agata Maciejak-Jastrzębska ◽  
Dariusz Sitkiewicz
Keyword(s):  
Atrial Fibrillation ◽  
Molecular Mechanisms ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Signalling Pathways ◽  
Ang Ii ◽  
Atrial Fibrosis ◽  
Genes Encoding ◽  
Tgf Β1

The cellular and molecular mechanism involved in the pathogenesis of atrial fibrosis are highly complex. We have reviewed the literature that covers the effectors, signal transduction and physiopathogenesis concerning extracellular matrix (ECM) dysregulation and atrial fibrosis in atrial fibrillation (AF). At the molecular level: angiotensin II, transforming growth factor-β1, inflammation, and oxidative stress are particularly important for ECM dysregulation and atrial fibrotic remodelling in AF. We conclude that the Ang-II-MAPK and TGF-β1-Smad signalling pathways play a major, central role in regulating atrial fibrotic remodelling in AF. The above signalling pathways induce the expression of genes encoding profibrotic molecules (MMP, CTGF, TGF-β1). An important mechanism is also the generation of reactive oxygen species. This pathway induced by the interaction of Ang II with the AT2R receptor and the activation of NADPH oxidase. Additionally, the interplay between cardiac MMPs and their endogenous tissue inhibitors of MMPs, is thought to be critical in atrial ECM metabolism and fibrosis. We also review recent evidence about the role of changes in the miRNAs expression in AF pathophysiology and their potential as therapeutic targets. Furthermore, keeping the balance between miRNA molecules exerting anti-/profibrotic effects is of key importance for the control of atrial fibrosis in AF.

scholarly journals Platelets Promote Ang II (Angiotensin II)-Induced Atrial Fibrillation by Releasing TGF-β1 (Transforming Growth Factor-β1) and Interacting With Fibroblasts

Hypertension ◽  
2020 ◽  
Vol 76 (6) ◽  
pp. 1856-1867
Author(s):  
Yang Liu ◽  
Haichen Lv ◽  
Ruopeng Tan ◽  
Xiangbo An ◽  
Xiao-Hui Niu ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Platelet Activation ◽  
Transforming Growth Factor ◽  
Platelet Inhibition ◽  
Transforming Growth Factor Β1 ◽  
Ang Ii ◽  
Atrial Fibrosis ◽  
Electrical Transmission ◽  
Platelet Accumulation ◽  
Tgf Β1

Hypertension is a risk factor of atrial fibrillation (AF), and a certain number of patients with hypertension were found with an enlarged left atrium. Platelet activation is found in patients with hypertension or pressure overload/Ang II (angiotensin II)-induced hypertensive animal models and contribute to ventricular fibrosis. Whether hypertension-induced atrial fibrosis is mediated by platelets remains unknown. Our previous experimental data showed that platelet-derived TGF-β1 (transforming growth factor-β1) was reduced in patients with hypertensive AF. The present study is to investigate whether platelet-derived TGF-β1 promotes Ang II-induced atrial fibrosis and AF. Platelet activation and atrial platelet accumulation were measured in sinus rhythm controls, normotensive AF, and patients with hypertensive AF. Ang II (1500 ng/kg per minute, 3 weeks) infused mice with pharmacological (clopidogrel) and genetic platelet inhibition (TGF-β1 deletion in platelets) were used. Platelet activation, atrial structural remodeling, atrial electrical transmission, AF inducibility, inflammation, and fibrosis were measured in mice. We found that circulating platelets were activated in patients with hypertensive AF. A large amount of platelet was accumulated in the atriums of patients with hypertensive AF. Both clopidogrel treatment and platelet-specific deletion of TGF-β1 attenuated Ang II-induced structural remodeling, atrial electrical transmission, AF inducibility, as well as atrial inflammation and fibrosis than mice without interventions. Furthermore, clopidogrel blocked atrial platelet accumulation and platelet-fibroblast conjugation. Platelets promoted atrial fibroblast differentiation in cell culture. Profibrotic actions of platelets are largely via activation of atrial fibroblasts by releasing TGF-β1 and inducing platelet-fibroblast conjugation, and platelet inhibition is sufficient to inhibit atrial fibrosis and AF inducibility.

scholarly journals Blockade of Exosome Release Suppresses Atrial Fibrillation by Alleviating Atrial Fibrosis in Canines With Prolonged Atrial Pacing

2021 ◽  
Vol 8 ◽  
Author(s):  
Yajun Yao ◽  
Shanqing He ◽  
Youcheng Wang ◽  
Zhen Cao ◽  
Dishiwen Liu ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Transforming Growth Factor ◽  
Canine Model ◽  
Transforming Growth Factor Β1 ◽  
Tissue Inhibitor Of Metalloproteinase ◽  
Atrial Pacing ◽  
Atrial Fibrosis ◽  
Exosome Biogenesis ◽  
Underlying Mechanisms ◽  
Tgf Β1

Background: Clinical studies have shown that exosomes are associated with atrial fibrillation (AF). However, the roles and underlying mechanisms remain unclear. Hence, this study aimed to investigate the function of exosomes in AF development.Methods: Twenty beagles were randomly divided into the sham group (n = 6), the pacing group (n = 7), and the pacing + GW4869 group (n = 7). The pacing and GW4869 groups underwent rapid atrial pacing (450 beats/min) for 7 days. The GW4869 group received intravenous GW4869 injection (an inhibitor of exosome biogenesis/release, 0.3 mg/kg, once a day) during pacing. Electrophysiological measurements, transmission electron microscopy, nanoparticle tracking analysis, western blotting, RT-PCR, Masson's staining, and immunohistochemistry were performed in this study.Results: Rapid atrial pacing increased the release of plasma and atrial exosomes. GW4869 treatment markedly suppressed AF inducibility and reduced the release of exosomes. After 7 days of pacing, the expression of transforming growth factor-β1 (TGF-β1), collagen I/III, and matrix metalloproteinases was enhanced in the atrium, and the levels of microRNA-21-5p (miR-21-5p) were upregulated in both plasma exosomes and the atrium, while the tissue inhibitor of metalloproteinase 3 (TIMP3), a target of miR-21-5p, showed a lower expression in the atrium. The administration of GW4869 abolished these effects.Conclusions: The blockade of exosome release with GW4869 suppressed AF by alleviating atrial fibrosis in a canine model, which was probably related to profibrotic miR-21-5p enriched in exosomes and its downstream TIMP3/TGF-β1 pathway.

scholarly journals Effect of miR-195-5p on cardiomyocyte apoptosis in rats with heart failure by regulating TGF-β1/Smad3 signaling pathway

2020 ◽  
Vol 40 (5) ◽  
Author(s):  
Chun Xie ◽  
Huaxin Qi ◽  
Lei Huan ◽  
Yan Yang
Keyword(s):  
Heart Failure ◽  
Cardiac Function ◽  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Cardiomyocyte Apoptosis ◽  
Luciferase Reporter ◽  
Rat Cardiomyocytes ◽  
Smad 3 ◽  
Tgf Β1

Abstract Purpose: The present study set out to investigate the effect of miR-195-5p on cardiomyocyte apoptosis in rats with heart failure (HF) and its mechanism. Methods: HF rat model and hypoxia/reoxygenation (H/R) cardiomyocyte model were established. miR-195-5p expression and transforming growth factor-β1 (TGF-β1)/signal transduction protein (Smad)3 signaling pathway in HF rats and H/R cardiomyocytes were interfered. miR-195-5p expression was tested by Rt-PCR, TGF-β1/Smad3 signaling pathway related proteins were detected by Western Blot, apoptosis of HF rat cardiomyocytes was tested by TUNEL, and apoptosis of cardiomyocytes induced by H/R was checked by flow cytometry. Results: miR-195-5p was lowly expressed in myocardium of HF rats, while TGF-β1 and Smad3 proteins were high-expressed. Up-regulating miR-195-5p expression could obviously inhibit cardiomyocyte apoptosis of HF rats, improve their cardiac function, and inhibit activation of TGF-β1/Smad3 signaling pathway. Up-regulation of miR-195-5p expression or inhibition of TGF-β1/Smad3 signaling pathway could obviously inhibit H/R-induced cardiomyocyte apoptosis. Dual-luciferase reporter enzyme verified the targeted relationship between miR-195-5p and Smad3. Conclusion: miR-195-5p can inhibit cardiomyocyte apoptosis and improve cardiac function in HF rats by regulating TGF-β1/Smad3 signaling pathway, which may be a potential target for HF therapy.

Abstract 251: Development of a Transgenic Goat Model with Cardiac-Specific Overexpression of Transforming Growth Factor-β1 to Study the Relationship Between Atrial Fibrosis and Atrial Fibrillation

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Irina A Polejaeva ◽  
Justin Hall ◽  
Qinggang Meng ◽  
Xinchang Zhou ◽  
Benjamin R Sessions ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Large Animal ◽  
Atrial Pacing ◽  
Atrial Fibrosis ◽  
Transgenic Goat ◽  
Large Animal Models ◽  
Fetal Fibroblasts ◽  
Tgf Β1

Studies on patients, large animal models and transgenic mouse models have shown a strong association of atrial fibrosis with atrial fibrillation (AF). However, it is unclear whether there is a causal relationship between atrial fibrosis and AF or whether these events appear as a result of independent pathological changes in the heart. We are testing the hypothesis that goats that overexpress TGF-β1 (transforming growth factor beta1) specifically in cardiac myocytes will develop atrial fibrosis that in turn will lead to AF. Many aspects of AF-related remodeling have been studied comprehensively in goat models. However, these AF models are typically mechanically induced (eg, the rapid atrial pacing model). This unique transgenic goat model has the potential to offer insights into the role of fibrosis in AF initiation and progression without the confounding effects of mechanical AF induction. Somatic cell nuclear transfer (SCNT or cloning) was used to produce TGF-β1 transgenic pregnancies. First, pcDNA3.1DV5-MHC-TGF-β1cys33ser vector was constructed by subcloning the MHC-TGF-β1 fragment from the plasmid pUC-BM20-MHC-TGF-β1 into the pcDNA3.1D V5 vector. The NeonTM transfection system was used to electroporate primary goat fetal fibroblasts. After two weeks of G418 selection, the resulting G418 resistant colonies were screened by PCR to confirm transgene integration into goat genomic DNA. PCR positive cells were used for SCNT. Cloned embryos (n=264) were cultured for 12-60 h in vitro and then transferred into synchronized recipient females (n=15). Confirmation of pregnancy was done by ultrasonography on day 30 post-transfer. At the time of this abstract submission, 40% (6/15) of recipients were confirmed to be pregnant as determined by the presence of a heartbeat. The range for the stage of gestation is between day-60 and day-120. The first delivery date is April 28, 2012. Several reports documented no pregnancy losses after 30 days of gestation in goats. Therefore, we expect that most if not all of these pregnancies will result in delivery of live offspring. To our knowledge, this will be the first transgenic goat model generated for cardiovascular research.

scholarly journals MG53/CAV1 regulates transforming growth factor-β1 signaling-induced atrial fibrosis in atrial fibrillation

Cell Cycle ◽  
2020 ◽  
Vol 19 (20) ◽  
pp. 2734-2744
Author(s):  
Meixia Zhang ◽  
Hechuan Wang ◽  
Xiaowen Wang ◽  
Mengjun Bie ◽  
Kai Lu ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Atrial Fibrosis

scholarly journals miR-15a-5p regulates myocardial fibrosis in atrial fibrillation by targeting Smad7

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12686
Author(s):  
Dan He ◽  
Zhong-bao Ruan ◽  
Gui-xian Song ◽  
Ge-cai Chen ◽  
Fei Wang ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Myocardial Fibrosis ◽  
Transforming Growth Factor ◽  
Cell Model ◽  
Transforming Growth Factor Β1 ◽  
Collagen I ◽  
Cell Counting ◽  
H9c2 Cell ◽  
Expression Levels ◽  
Tgf Β1

Background At present, there is no effective treatment for myocardial fibrosis in atrial fibrillation (AF). It is reported that miR-15a-5p is abnormally expressed in AF patients but its specific role remains unclear. This study aims to investigate the effect of miR-15a-5p in myocardial fibrosis. Methods Left atrial appendage (LAA) tissues were collected from AF and non-AF patients. In lipopolysaccharide (LPS) stimulated H9C2 cells, miR-15a-5p mimic, inhibitor, pcDNA3.1-Smad7 and small interfering RNA-Smad7 (siRNA-Smad7) were respectively transfected to up-regulate or down-regulate the intracellular expression levels of miR-15a-5p and Smad7. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB) were used to determine the expression levels of miR-15a-5p, Smad7, transforming growth factor β1 (TGF-β1) and collagen I. Cell counting kit-8 (CCK-8) and ethylene deoxyuridine (EdU) were used to determine cell viability and proliferation capacity, respectively. Dual-luciferase was used to detect whether miR-15a-5p interacted with Smad7, hydroxyproline (HYP) and Hematoxylin-Eosin (HE) staining were used to detect tissue fibrosis. Results The expression levels of miR-15a-5p, TGF-β1 and collagen I were up-regulated, while Smad7 was down-regulated in AF tissues and LPS-stimulated cells. MiR-15a-5p mimic can inhibit the expression of Smad7, and the dual-luciferase experiment confirmed their interaction. MiR-15a-5p inhibitor or pcDNA3.1-Smad7 can inhibit LPS-induced fibrosis and cell proliferation, while siRNA-Smad7 can reverse the changes caused by miR-15a-5p inhibitor. Conclusion We combined clinical studies with LPS-stimulated H9C2 cell model to validate the role of miR-15a-5p in the regulation of Smad7 and fibrosis. Taken together, the miR-15a-5p/Smad7 pathway might be a potential target for AF therapy.

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