Effect of carvedilol on cardiomyocyte apoptosis in a rat model of myocardial infarction: a role for toll-like receptor 4

Programmed death of cardiomyocytes in cardiovascular disease and new therapeutic approaches

Cardiovascular diseases (CVDs) have a complex pathogenesis and pose a major threat to human health. Cardiomyocytes have a low regenerative capacity, and their death is a key factor in the morbidity and mortality of many CVDs. Cardiomyocyte death can be regulated by specific signaling pathways known as programmed cell death (PCD), including apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, etc. Abnormalities in PCD can lead to the development of a variety of cardiovascular diseases, and there are also molecular-level interconnections between different PCD pathways under the same cardiovascular disease model. Currently, the link between programmed cell death in cardiomyocytes and cardiovascular disease is not fully understood. This review describes the molecular mechanisms of programmed death and the impact of cardiomyocyte death on cardiovascular disease development. Emphasis is placed on a summary of drugs and potential therapeutic approaches that can be used to treat cardiovascular disease by targeting and blocking programmed cell death in cardiomyocytes.

Influence of carvedilol and thyroid hormones on inflammatory proteins and cardioprotective factor HIF-1α in the infarcted heart

Inflammatory pathways of Toll-like receptor 4 (TLR4) and NLRP3 inflammasome contribute to acute myocardial infarction (AMI) pathophysiology. The hypoxia-inducible factor 1α (HIF-1α), however, is a key transcription factor related to cardioprotection. This study aimed to compare the influence of carvedilol and thyroid hormones (TH) on inflammatory and HIF-1α proteins and on cardiac haemodynamics in the infarcted heart. Male Wistar rats were allocated into five groups: sham-operated group (SHAM), infarcted group (MI), infarcted treated with the carvedilol group (MI + C), infarcted treated with the TH group (MI + TH), and infarcted co-treated with the carvedilol and TH group (MI + C + TH). Haemodynamic analysis was assessed 15 days post-AMI. The left ventricle (LV) was collected for morphometric and Western blot analysis. The MI group presented LV systolic pressure reduction, LV end-diastolic pressure elevation, and contractility index decrease compared to the SHAM group. The MI + C, MI + TH, and MI + C + TH groups did not reveal such alterations compared to the SHAM group. The MI + TH and MI + C + TH groups presented reduced MyD88 and NLRP3 and increased HIF-1α levels. In conclusion, all treatments preserve the cardiac haemodynamic, and only TH, as isolated treatment or in co-treatment with carvedilol, was able to reduce MyD88 and NLRP3 and increase HIF-1α in the infarcted heart.

Inappropriate Activation of TLR4/NF-κB is a Cause of Heart Failure

Significance: Heart failure, a disease with extremely high incidence, is closely associated with inflammation and oxidative stress. The Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway plays an important role in the occurrence and development of heart failure.

Recent advances: Previous studies have shown that TLR4/NF-κB causes heart failure by inducing oxidative stress and inflammation; damaging the endothelia; promoting fibrosis; and inducing myocardial hypertrophy, apoptosis, pyroptosis, and autophagy.

Critical issues: Understanding the pathogenesis of heart failure is essential for the treatment of this disease. In this review, we outline the mechanisms underlying TLR4/NF-κB pathway-mediated heart failure and discuss drugs that alleviate heart failure by regulating the TLR4/NF-κB pathway.

Future directions: During TLR4/NF-κB overactivation, interventions targeting specific receptor antagonists may effectively alleviate heart failure, thus providing a basis for the development of new anti-heart failure drugs.

Neuroprotective repositioning and anti-tau effect of carvedilol on rotenone induced neurotoxicity in rats: Insights from an insilico& in vivo anti-Parkinson's disease study

Current treatments for Parkinson's Disease (PD) only provide symptomatic relief; however, they don't delay the disease progression, hence new treatment options should be considered. Carvedilol is a nonselective β & α1 blocker with additional effects as an antioxidant, anti-inflammatory and neuro protective properties. In this research, an insilico study was conducted to primarily evaluate carvedilol as an anti-parkinsonian and anti-tau protein target. PASS prediction was performed followed by a docking study of carvedilol. Carvedilol yielded promising results and forward guided this study onto its in vivo evaluation. The in vivo study aimed to assess the neuro-protective effects of carvedilol in rotenone-induced rat model of PD and investigate the potential underlying mechanisms. The effects of carvedilol (2.5, 5, and 10 mg/kg) on the measured parameters of open field, catalepsy, Y-maze tests as well as brain histology, and tyrosine hydroxylase (TH) were evaluated. The effective doses (5 and 10 mg/kg) were further tested for their potential anti-tau protein effects. Carvedilol (5 and 10 mg/kg) prevented rotenone-induced motor deficits, spatial memory dysfunction, and histological damage. Additionally, carvedilol significantly inhibited rotenone-induced decrease in TH expression in the striata of the rats. These effects were associated with reduction of rotenone-induced neuro-inflammation, microglial activation and release of glial fibrillary acidic protein (GFAP), along with reduction in N-methyl-D-aspartate receptors activation, alpha-synculein and phospho-Tau (P-Tau) protein expression. Carvedilol also reduced tau protein hyper-phosphosrylation by Glycogen synthase 3β (GSK 3β) inhibition and Phosphoinositide 3-kinase (PI3K) stimulation. Collectively, these results suggest that carvedilol might be a possible candidate for management of PD.

Potential role of carvedilol in intestinal toxicity through NF-κB/iNOS/COX-2/TNF-α inflammatory signaling pathway in rats

BACKGROUND

The increased use of indomethacin (IND) is associated with gastrointestinal injury. This research aims to investigate the effects of a beta-blocker, carvedilol (CAR) on a rat model of IND-induced acute intestinal damage and clarify the probable underlying protective mechanisms.

MATERIALS AND METHODS

Twenty-four male Wistar rats were divided into four groups. Control group: given vehicles; CAR-treated group: given 10 mg/kg/day CAR PO daily by gastric gavage for 10 consecutive days; IND-treated group: given a single Sc dose of 10 mg/kg IND at the end of the ninth day of the experiment; combined CAR/IND-treated group: given both IND and CAR.

RESULTS

In the rats that received IND, severe intestinal histopathological changes together with oxidative and nitrosative intestinal stress were present biochemically and immunohistochemically. Obvious inflammatory and tissue damage were represented by the significant intestinal increases in TNF-α, COX-2, and caspase-3 together with the elevated expression of VCAM-1 adhesion molecules. Intestinal gene expression of NF-kB and COX-2 was also increased. Pretreatment with CAR significantly reversed the IND-induced intestinal toxic manifestations.

CONCLUSION

CAR has beneficial intestinal protective effects. Its ameliorative action is conferred through its antioxidant, antinitrosative, anti-inflammatory, and antiapoptotic properties.

Effects of Carvedilol and Thyroid Hormones Co-administration on Apoptotic and Survival Proteins in the Heart After Acute Myocardial Infarction

Cellular death and survival signaling plays a key role in the progress of adverse cardiac remodeling after acute myocardial infarction (AMI). Therapeutic strategies, such as co-treatment with beta-blocker carvedilol and thyroid hormones (THs), give rise to new approaches that can sustain the cellular homeostasis after AMI. Therefore, we sought to investigate the effects of carvedilol and TH co-administration on apoptosis and survival proteins and on cardiac remodeling after AMI. Male Wistar rats were distributed in 5 groups as follows: sham-operated group (SHAM), infarcted group (MI), infarcted plus carvedilol group (MI+C), infarcted plus TH group (MI+TH), and infarcted plus carvedilol and TH co-treatment group (MI+C+TH). Echocardiographic analysis was performed, and hearts were collected for western blot evaluation. The MI group presented systolic posterior wall thickness loss, an increase in the wall tension index, and an increase in atrial natriuretic peptide tissue levels than the SHAM group. However, in the MI+C+TH group, these parameters were equally to the SHAM group. Moreover, whereas the MI group showed Bax protein expression elevated in relation to the SHAM group, the MI+C+TH group presented Bax reduction and also Akt activation compared with the MI group. In addition, the MI+TH group revealed beta-1 adrenergic receptor (β1AR) upregulation compared with the MI and MI+C groups, whereas the MI+C+TH group presented lower levels of β1AR in relation to the SHAM and MI+TH groups. In conclusion, we suggest that carvedilol and TH co-administration may mediate its cardioprotective effects against adverse cardiac remodeling post-AMI through the Bax reduction, Akt activation, and β1AR decrease.

Carvedilol protects against the H2O2-induced cell damages in rat myoblasts by regulating the circ_NFIX/miR-125b-5p/TLR4 signal axis

ABSTRACT

Circular RNAs (circRNAs) have been involved in the regulation of various kinds of cardiovascular diseases, including acute myocardial infarction (AMI). This study was performed to investigate the molecular mechanism associated with circRNA nuclear factor IX (circ_NFIX) in carvedilol-mediated cardioprotection in H2O2-treated H9c2 cells. Flow cytometry was performed for the analysis of cell cycle and apoptosis. Cell proliferation was evaluated using colony formation assay and 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Lactate dehydrogenase (LDH) activity was measured via LDH assay. The relative levels of circ_NFIX, microRNA-125b-5p (miR-125b-5p) and toll-like receptor 4 (TLR4) were determined via quantitative real-time polymerase chain reaction (qRT-PCR). Protein levels were examined by western blot. The target interaction was proved via dual-luciferase reporter assay. H2O2-induced cell cycle arrest, proliferation repression, apoptosis and LDH promotion in H9c2 cells were inhibited by carvedilol. Circ_NFIX level was reduced after carvedilol treatment in H2O2-treated H9c2 cells, and circ_NFIX overexpression inhibited the protective effects of carvedilol on H2O2-induced cell damages. Furthermore, circ_NFIX was validated to serve as a sponge of miR-125b-5p and the inhibitory function of circ_NFIX in carvedilol-induced cardioprotection was achieved by sponging miR-125b-5p. Moreover, TLR4 acted as a target gene of miR-125b-5p and miR-125b-5p inhibitor upregulated the TLR4 expression to suppress the protective effects of carvedilol on H2O2-treated H9c2 cells. In addition, circ_NFIX regulated the TLR4 level by exerting the sponge influence on miR-125b-5p. Rat model also indicated that Carv might suppressed the progression of AMI via regulating the levels of circ_NFIX, miR-125b-5p and TLR4. These findings suggested that carvedilol protected H9c2 cells against the H2O2-induced cell dysfunction through depending on the circ_NFIX/miR-125b-5p/TLR4 axis.

Rosuvastatin and low-dose carvedilol combination protects against isoprenaline-induced myocardial infarction in rats: Role of PI3K/Akt/Nrf2/HO-1 signalling

Rosuvastatin has been shown to activate PI3K/Akt/Nrf2/HO-1 pathway, which promotes cell survival in the myocardium. This study investigated the therapeutic benefit of adding rosuvastatin to low-dose carvedilol in protection against myocardial infarction (MI). Rosuvastatin (RSV) and carvedilol (CAR) were given for 7 consecutive days with concurrent administration of two doses of isoprenaline (ISP) on 6th and 7th days to induce MI. Isoprenaline injections caused detrimental alterations in the myocardial architecture and electrocardiogram (ECG) pattern and significantly increased the infarct size, heart index and serum levels of cardiotoxicity markers compared to the control group. ISP induced oxidative damage, inflammatory and apoptotic events and downregulated PI3K/Akt/Nrf2/HO-1 signalling pathway compared to the control values. Treatment with low-dose CAR and/or RSV prevented the ECG and histopathological alterations induced by ISP, and also reduced the infarct size, heart index, serum creatine kinase-MB, cardiac troponin-I and C-reactive protein levels compared to ISP group. CAR and/or RSV treatment restored the activity of superoxide dismutase and total antioxidant capacity with a consequent reduction in lipid peroxides level. Further, they decreased the expression of nuclear factor (NF)-κB (p65) and increased the phosphorylated PI3K and Akt, which may activate the anti-apoptotic signalling as evidenced by the decreased active caspase 3 level. The combination therapy has a more significant effect in the most studied parameters than their monotherapy, which may be because of the activation of PI3K/Akt Nrf2/HO-1 pro-survival signalling pathway. This study highlights the potential benefits of combining RSV with low-dose CAR in case of MI.

Oxidative Stress in Ischemic Heart Disease

One of the novel interesting topics in the study of cardiovascular disease is the role of the oxidation system, since inflammation and oxidative stress are known to lead to cardiovascular diseases, their progression and complications. During decades of research, many complex interactions between agents of oxidative stress, oxidation, and antioxidant systems have been elucidated, and numerous important pathophysiological links to na number of disorders and diseases have been established. This review article will present the most relevant knowledge linking oxidative stress to vascular dysfunction and disease. The review will focus on the role of oxidative stress in endotheleial dysfunction, atherosclerosis, and other pathogenetic processes and mechanisms that contribute to the development of ischemic heart disease.

The role of toll-like receptors in myocardial toxicity induced by doxorubicin

Doxorubicin is an effective antitumor drug commonly used in the treatment of a wide variety of cancers. However, doxorubicin may cause cardiac toxicity, which can cause congestive heart failure in severe cases, and this seriously limits its clinical application. It is believed that doxorubicin promotes the formation of reactive oxygen species, inducing oxidative stress, and at the same time, reduces the content of antioxidant substances in cardiac tissues, causing adverse effects. Toll-like receptors (TLRs) are biomolecules expressed on the surfaces of macrophages, dendritic cells, and epithelial cells that can recognize various types of pathogen-related or damage-related molecular patterns. In recent years, a large number of studies have confirmed that TLRs play important roles in the cardiac toxicity induced by doxorubicin. This review aimed to explore the role of TLRs in the cardiac toxicity induced by doxorubicin and provide possible solutions.

Iron overload inhibits late stage autophagic flux leading to insulin resistance

Iron overload, a common clinical occurrence, is implicated in the metabolic syndrome although the contributing pathophysiological mechanisms are not fully defined. We show that prolonged iron overload results in an autophagy defect associated with accumulation of dysfunctional autolysosomes and loss of free lysosomes in skeletal muscle. These autophagy defects contribute to impaired insulin-stimulated glucose uptake and insulin signaling. Mechanistically, we show that iron overload leads to a decrease in Akt-mediated repression of tuberous sclerosis complex (TSC2) and Rheb-mediated mTORC1 activation on autolysosomes, thereby inhibiting autophagic-lysosome regeneration. Constitutive activation of mTORC1 or iron withdrawal replenishes lysosomal pools via increased mTORC1-UVRAG signaling, which restores insulin sensitivity. Induction of iron overload via intravenous iron-dextran delivery in mice also results in insulin resistance accompanied by abnormal autophagosome accumulation, lysosomal loss, and decreased mTORC1-UVRAG signaling in muscle. Collectively, our results show that chronic iron overload leads to a profound autophagy defect through mTORC1-UVRAG inhibition and provides new mechanistic insight into metabolic syndrome-associated insulin resistance.

MicroRNA‑1 downregulation induced by carvedilol protects cardiomyocytes against apoptosis by targeting heat shock protein 60

Myocardial infarction (MI) is the most common event in cardiovascular disease. Carvedilol, a β‑blocker with multiple pleiotropic actions, is widely used for the treatment cardiovascular diseases. However, the underlying mechanisms of carvedilol on alleviating MI are not fully understood. The aim of the present study was to investigate whether the beneficial effects of carvedilol were associated with regulation of microRNA‑1 (miR‑1). It was demonstrated that carvedilol ameliorated impaired cardiac function and decreased infarct size in a rat model of MI induced by coronary artery occlusion. Similarly, carvedilol reversed the H2O2‑induced decrease in cardiomyocyte viability in a dose‑dependent manner. The in vivo and in vitro models demonstrated the downregulation of miR‑1 following treatment with carvedilol. Overexpression of miR‑1, a known pro‑apoptotic miRNA, decreased cell viability and induced cell apoptosis. Transfection of miR‑1 abolished the beneficial effects of carvedilol. The expression of heat shock protein 60 (HSP60), a direct target of miR‑1, was identified to be decreased in MI and H2O2‑induced apoptosis, which was associated with a decrease in Bcl‑2 and an increase in Bax; expression was restored following treatment with carvedilol. It was concluded that carvedilol partially exhibited its beneficial effects by downregulating miR‑1 and increasing HSP60 expression. miR‑1 has become a member of the group of carvedilol‑responsive miRNAs. Future studies are required to fully elucidate the potential overlapping or compensatory effects of known carvedilol‑responsive miRNAs and their underlying mechanisms of action in the pathophysiology of cardiovascular diseases.

Fluvastatin inhibits cardiomyocyte apoptosis after myocardial infarction through Toll pathway

The present study intended to investigate the effect of fluvastatin on cardiomyocyte apoptosis after myocardial infarction in rats. Eighty myocardial infarction rat models were established and randomly divided into 4 groups (n=20): experimental group (n=20) was given fluvastatin treatment; sham operation group (n=20) and normal control group (n=20) were given saline. The dose of fluvastatin was 20 mg/(kg·d), and irrigation gavage was given for 1 week. Western blot analysis and reverse transcription-quantitative PCR (RT-qPCR) were used to detect the expression of TLR4 mRNA and protein in cardiomyocytes. TUNEL method was used to detect the apoptosis of cardiomyocytes. After fluvastatin treatment for 1 week, RT-qPCR found that compared with myocardial infarction group, the TLR4 mRNA expression of fluvastatin treatment group and normal control group was significantly increased, and the differences between groups were a statistically significant difference (P<0.05). Western blot analysis showed that compared with the myocardial infarction group, the expression of TLR4 protein in normal control group, sham operation group and fluvastatin treatment group were significantly decreased, and they all were statistically significant (P<0.05). TUNEL method found that compared with the myocardial infarction group, the fluvastatin treatment group could significantly reduce the apoptosis of cardiomyocytes (19.2±3.8%), and the difference was statistically significant (P<0.05). Fluvastatin can inhibit myocardial infarction and decrease cardiomyocyte apoptosis by increasing the expression of TLR4-like receptor.

Isoquercetin ameliorates myocardial infarction through anti-inflammation and anti-apoptosis factor and regulating TLR4-NF-κB signal pathway

The aim of the present study was to investigate the protective mechanisms and identify the effects of isoquercetin on myocardial infarction in a rat model of acute myocardial infarction (AMI). Isoquercetin ameliorated myocardial infarct size, creatine kinase (CK), CK‑MB and lactic dehydrogenase activity and inhibited inflammation, oxidative stress and heart cell apoptosis in a rat with AMI. Isoquercetin increased endothelial nitric oxide synthase, reduced inducible nitric oxide synthase levels and suppressed the Toll-like receptor 4‑nuclear factor (TLR4‑NF)‑κB signaling pathway in a rat with AMI. Overall, isoquercetin ameliorated AMI through anti‑inflammatory and anti‑apoptotic factors, and regulation of the TLR4‑NF‑κB signaling pathway. Isoquercetin may therefore potentially exert a protective effect against AMI or other heart diseases.

Astragaloside protects myocardial cells from apoptosis through suppression of the TLR4/NF-κB signaling pathway

Astragaloside is a monomer isolated from Astragalus membranaceus, a flowering plant in the family Fabaceae. The aim of the present study was to investigate the anti-apoptotic affect of astragaloside on myocardial cells through the TLR4/NF-κB signaling pathway. Astragaloside, NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) and Toll-like receptor 4 (TLR4) blocking antibody solution were prepared in vitro, and myocardial cells were incubated and cultured in serum-free medium overnight. Cells were divided into five groups: the normal control group, serum-free group, astragaloside group, TLR4 blocking antibody group and NF-κB inhibitor PDTC group. The myocardial cell apoptosis in each group was detected using flow cytometry, and the expression levels of TLR4 and NF-κB were detected via western blotting. The apoptosis rate in the serum-free group was significantly higher than that in the normal control group. The apoptosis rate of myocardial cells in the TLR4 blocking antibody group and NF-κB inhibitor PDTC group was lower than that in the serum-free group. In addition, the myocardial cell apoptosis was more obviously decreased in the astragaloside group, and the protein expression levels of TLR4 and NF-κB in the serum-free group were significantly higher than those in normal control group. The protein expression levels of TLR4 and NF-κB in the astragaloside group were obviously lower than those in the serum-free group, and the protein expression levels of TLR4 and NF-κB in the TLR4 blocking antibody group and NF-κB inhibitor PDTC group were decreased. In conclusion, astragaloside reduced myocardial cell apoptosis and protected myocardial cells, which may be one of the mechanisms of a traditional Chinese medicine monomer in treating heart failure.

Efficacy of gold nanoparticles against isoproterenol induced acute myocardial infarction in adult male albino rats

This study was undertaken to investigate the role of gold nanoparticles (GNPs) of 50 nm diameter on isoproterenol (ISO) induced acute myocardial infarction in adult male albino rats. Forty five adult Wistar male albino rats were equally divided into three groups. Control (group I) was further subdivided into three subgroups. In group II, the rats received ISO subcutaneously at a dose of 100 mg/kg for three days. In group III, rats received ISO as group II and then GNPs (400 μg/kg/day) intravenously for 14 consecutive days. Echocardiography was performed. Left ventricular specimens were prepared for H&E, van Gieson staining, immunohistochemical analysis for (eNOs and Bcl-2), and Electron microscope examination. Energy dispersive X-ray microanalysis was also performed. Cardiac markers such as creatine Kinase-MB (CK-MB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and cardiac troponin T (cTnT) were measured. Group II revealed cardiomyocytes with deeply stained acidophilic cytoplasm, small dark nuclei, intracellular vacuolations, wide intercellular spaces, and extravasated red blood cells. Increased collagen fibers were observed. Electron microscope examination showed cardiomyocyte with small and irregular outlined nuclei, mitochondria with irregular cristae and others with ruptured mitochondrial membrane, abnormal alignment of myofibrils, dilated cisternae of smooth endoplasmic reticulum, and disorganized intercalated discs. Group III showed that most cardiomyocytes preserved the normal architecture. Increased expression of eNOs immunoreaction and decreased Bcl-2 immunoreaction were detected in group II as compared to the control and GNP-treated groups. These findings suggested that GNPs of 50 nm diameter improved myocardial injury after ISO-induced myocardial infarction in rats.

ABBREVIATIONS

Myocardial infarction (MI), Isoproterenol (ISO), Nitric oxide (NO), Neuronal NOS (nNOs), Endothelial NOs (eNOs), Gold nanoparticle (GNPs), Diamiobenzidine (DAB), Serum Creatine Kinase-MB (CK-MB), Alanine aminotransferase (ALT), Cardiac troponin T (cTnT), Electrochemiluminiscence (ECLIA), Cardiomyocytes (CMC), Peroxisomal proliferator activated receptor (PPARs), Reactive oxygen species (ROS).

Cardioprotective effect of carvedilol: inhibition of apoptosis in H9c2 cardiomyocytes via the TLR4/NF-κB pathway following ischemia/reperfusion injury

Carvedilol is a non-selective β-blocker used in the treatment of cardiovascular disease, including myocardial ischemia. The aim of the present study was to investigate the molecular mechanisms underlying the effects of carvedilol on simulated ischemia/reperfusion (SI/R)-induced cardiomyocyte apoptosis in vitro. H9c2 cardiomyocytes were incubated with either a vehicle or an ischemic buffer during hypoxia followed by reoxygenation with or without carvedilol. In two additional groups, toll-like receptor 4 (TLR4) and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) were inhibited by a TLR4 antibody and pyrrolidine dithiocarbamate, respectively. The results revealed that carvedilol markedly decreased SI/R-induced apoptosis in a concentration-dependent manner, as demonstrated by flow-cytometric analysis. This effect was shown to be associated with an increase in the B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X (Bax) protein ratio and concurrent reductions in the expression levels of TLR4 and NF-κB. These results suggest that carvedilol provides significant cardioprotection against SI/R-induced injury in H9c2 cardiomyocytes, an effect likely to be mediated through the TLR4/NF-κB signaling pathway.