Cardiac Reactive Oxygen Species Research Articles

Klotho is cardioprotective in the mdx mouse model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is a lethal, progressive skeletal and cardiac myopathy. Cardiomyopathy is the leading cause of death in DMD patients but the molecular basis for heart failure is incompletely understood. Like humans, in the mdx mouse model of DMD cardiac function is impaired after the onset of skeletal muscle pathology. Dysregulation of Klotho gene regulation in dystrophic skeletal muscles occurs at disease onset affecting pathogenesis. Whether Klotho is protective against dystrophin-deficient cardiomyopathy is unknown. Here, we showed that expression of a Klotho transgene prevented deficits in left ventricular ejection fraction and fractional shortening in mdx mice. Improvements in cardiac performance were associated with reductions in adverse cardiac remodeling, cardiac myocyte hypertrophy and fibrosis. In addition, mdx mice expressed high concentrations of plasma fibroblast growth factor 23 (FGF23) and expression was increased locally in hearts. The cardioprotective effects of Klotho were not associated with differences in renal function or serum biochemistries, but transgene expression prevented increased expression of plasma FGF23 and cardiac Fgf23 mRNA expression. Cardiac reactive oxygen species, oxidative damage, mitochondrial damage, and apoptosis were reduced in transgenic hearts. Our findings also showed that FGF23 stimulates hypertrophic growth in dystrophic neonatal mouse ventricular myocytes in vitro, which was inhibited by co-stimulation with soluble Klotho. Taken together, these results demonstrate that Klotho prevented dystrophic cardiac remodeling and improved function.

Metformin Regulates Cardiac Ferroptosis to Reduce Metabolic Syndrome-Induced Cardiac Dysfunction.

High-fat diet-induced metabolic syndrome (MetS) is closely associated with cardiac dysfunction. Recent research studies have indicated a potential association between MetS and ferroptosis. Furthermore, metformin can alleviate MetS-induced cardiac ferroptosis. Metformin is a classic biguanide anti-diabetic drug that has protective effects on cardiovascular diseases, which extend beyond its indirect glycemic control. This study aimed to assess whether MetS mediates cardiac ferroptosis, thereby causing oxidative stress and mitochondrial dysfunction. The results revealed that metformin can mitigate cardiac reactive oxygen species and mitochondrial damage, thereby preserving cardiac function. Mechanistic analysis revealed that metformin upregulates the expression of cardiac Nrf2. Moreover, Nrf2 downregulation compromises the cardio-protective effects of metformin. In summary, this study indicated that MetS promotes cardiac ferroptosis, and metformin plays a preventive and therapeutic role, partially through modulation of Nrf2 expression.

Cardiotoxicity risk induced by sanitary insecticide Dimefluthrin

Dimefluthrin (DIM) is a commonly utilized sanitary insecticide, predominantly employed for indoor pest management within residential and public environments directly interacting with human habitation. However, the usage of DIM is escalating with increasing mosquito resistance, prompting concerns about its health risks. Here, using zebrafish as a research model, we systematically evaluated DIM's impact on human health. Findings revealed significant health hazards during embryonic development, including reduced hatching rates, shortened body lengths, and organ malformations, notably affecting the heart. It was explored the mechanism of DIM-induced cardiotoxicity in zebrafish, and histopathological analyses revealed that DIM resulted in ventricular linearization in zebrafish embryos. Antioxidant enzyme activities were reduced and cardiac reactive oxygen species (ROS) accumulated after DIM exposure, suggesting clear signs of oxidative stress. Additionally, acridine orange (AO) staining and caspase-3 immunofluorescence demonstrated cardiac apoptosis in Tg (kdrl: EGFP) zebrafish. qPCR analysis implied that DIM induced apoptosis via the p53/Caspase pathway by up-regulating the expression levels of p53, cytochrome C (cyto-C), caspase-9, and caspase-3. Together, our work provided a systematic perspective on the cardiotoxicity of sanitary pesticides, which could offer opportunities for future risk management.

In utero chronic intermittent nicotine aerosol exposure increases ischemic heart injury in adult offspring via programming of Angiotensin II receptor-derived TGFβ/ROS/Akt signaling pathway

BackgroundIn utero cigarette smoking/nicotine exposure during pregnancy significantly affects fetal development and increases the risk of cardiovascular disease late in life. However, the underlying molecular mechanisms remain largely unknown. We tested the hypothesis that fetal nicotine aerosol exposure reprograms ischemia-sensitive gene expressions, resulting in increased heart susceptibility to ischemic injury and cardiac dysfunction in adulthood. MethodsPregnant rats were exposed to chronic intermittent nicotine aerosol (CINA) or saline aerosol control from gestational day 4 to day 21. Experiments were performed on 6-month–old adult offspring. ResultsCINA exposure increased ischemia-induced cardiac injury and cardiac dysfunction compared to the control group, which was associated with over- expression of angiotensin II receptor (ATR) protein in the left ventricle (LV) of adult offspring. Meanwhile, CINA exposure up-regulated cardiac TGF-β/SMADs family proteins in the LV. In addition, CINA exposure enhanced cardiac reactive oxygen species (ROS) production and increased the DNA methylation level. The levels of phosphorylated-Akt were upregulated but LC3B-II/I protein abundances were downregulated in the hearts isolated from the CINA-treated group. ConclusionFetal nicotine aerosol exposure leads to cardiac dysfunction in response to ischemic stimulation in adulthood. Two molecular pathways are implicated. First, fetal CINA exposure elevates cardiac ATR levels, affecting the TGFβ-SMADs pathway. Second, heightened Angiotensin II/ATR signaling triggers ROS production, leading to DNA hypermethylation, p-Akt activation, and autophagy deficiency. These molecular shifts in cardiomyocytes result in the development of a heart ischemia-sensitive phenotype and subsequent dysfunction in adult offspring.

Moderate-Intensity Swimming Alleviates Oxidative Injury in Ischemic Heart

The global burden of cardiovascular diseases is indisputable, as it claims nearly 18 million lives a year. In this current study, we aimed to prove that exercise, a cornerstone in cardiovascular disease management, emerges as a powerful tool in the pathology of myocardial ischemia. Male rats were divided into three groups: pre-swimming training + isoproterenol (ISO) treated, isoproterenol-treated, and control-sedentary. Myocardial infarction was induced by the subcutaneous injection of 1.0 mg/kg ISO. After the subsequent rest period, the animals swam for 3 weeks, every day for 25 min. At the end of the experiment, the serum levels of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP), as well as the cardiac concentrations of reactive oxygen species (ROS), catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were determined. Our results indicate that both cardiac injury biomarkers (ANP, BNP) and ROS levels were significantly lower in swimming rats compared to the sedentary animals. Moreover, the level of enzymatic components of the intracellular antioxidant system, CAT, SOD, and GPx were increased in swimming animals after ISO-induced myocardial infarction. Our findings support the fact that moderate-intensity swimming training can be efficiently used to prevent myocardial infarction-induced ischemic injury, by inhibiting ROS production and strengthening intracellular antioxidant defense.

ALDH2 mitigates LPS-induced cardiac dysfunction, inflammation, and apoptosis through the cGAS/STING pathway

BackgroundSepsis is a severe syndrome of organ dysfunction that often leads to cardiac dysfunction and endangers life. The role of mitochondrial aldehyde dehydrogenase 2 (ALDH2) in LPS-induced myocardial injury is unclear. The purpose of this study was to assess the role of ALDH2 in lipopolysaccharide (LPS)-induced myocardial injury and the regulatory mechanism and to identify potential therapeutic strategies for treating this condition.MethodsAn in vivo model was established by 12 h of LPS (10 mg/kg, intraperitoneal injection) stimulation, and an in vitro model was generated by stimulating H9C2 cells with LPS (10 μg/ml) for 12 h. We then used the ALDH2 activator Alda-1 and the ALDH2 inhibitor daidzin to assess their effects on LPS-induced cardiac injury. Cardiac function in mice was evaluated by using cardiac ultrasound. We used various methods to evaluate inflammation, apoptosis, and oxidative stress, including ELISA, flow cytometry, JC-1 staining, Western blotting, and DCFH-DA staining. Additionally, we used a small interfering RNA (siRNA) to knock down cyclic GMP-AMP synthase (cGAS) to further investigate the relationship between ALDH2 and cGAS in LPS-induced cardiac injury.ResultsLPS-induced cardiac dysfunction and increased the levels of the cardiac injury markers creatine kinase-MB (CKMB) and lactate dehydrogenase (LDH) in vivo. This change was accompanied by an increase in reactive oxygen species (ROS) levels, which exacerbated the oxidative stress response and regulated apoptosis through cleaved caspase-3, BAX, BCL-2. The expression of inflammatory cytokines such as IL-6/IL-1β/TNF-α was also upregulated. However, these effects were reversed by pretreatment with Alda-1 via the inhibition of cGAS/stimulator of interferon genes (STING) signaling pathway. Interestingly, LPS, Alda-1 and daidzin altered the activity of ALDH2 but did not regulate its protein expression. Knocking down cGAS in H9C2 cardiomyocytes alleviated LPS-induced cardiac inflammation, apoptosis, and ROS production and weakened the synergistic effect of daidzin.ConclusionWe demonstrated that ALDH2 alleviated LPS-induced cardiac dysfunction, inflammation, and apoptosis through the cGAS/STING signaling pathway, thereby protecting against LPS-induced cardiac injury. This study identifies a novel therapeutic approach for treating sepsis-induced cardiomyopathy (SIC).

Myrtle Berries Seeds Prevent Dyslipidemia, Inflammation, and Excessive Cardiac Reactive Oxygen Species Production in Response to High-Fat Diet-Induced Obesity.

Anthocyanins are the major polyphenols in myrtle berries seeds aqueous extract (MBSAE). This study investigates the protective potentials of MBSAE against obesity lipotoxicity and inflammation induced by a high-fat diet (HFD). It also describes the underlying mechanisms involved in its protective effects, with special attention to myocardial reactive oxygen species (ROS) production. Male Wistar rats were fed HFD for 6 weeks to induce obesity. MBSAE (100 mg/kg, b.w., p.o.) was orally administered to HFD-fed rats. Anti-obesity effects were triggered by the inhibitory action of the MBSAE against the weights of the body, its relative heart and the total abdominal fat. Treatment with MBSAE also restored the lipid profile to baseline compared with the HFD rats and lowered also the white blood cells count, including neutrophils, lymphocytes, and basophils number as well as cytokines (tumor necrosis factor-α, interleukin [IL]-6, and IL-1β) levels in the rats serum, thus improving the tissue inflammatory status associated with obesity. Exposure of rats to HFD during 6 weeks induces a myocardial oxidative stress as assessed by deleterious effects on lipoperoxidation state, antioxidant enzyme (SOD, CAT, and GPx) activities as well as sulfhydryl groups and GSH rates. Of importance, our study shows also that HFD provokes a heart ROS (H2O2, OH•, and O2•-) overload. Of interest, all these oxidative heart disturbances were clearly ended by MBSAE treatment. Therefore, consumption of MBSAE as a natural extract may be a potential therapeutic strategy to treat obesity-associated diseases.

Protective effects of β-caryophyllene on mitochondrial damage and cardiac hypertrophy pathways in isoproterenol-induced myocardial infarcted rats

The cardiac mitochondrial damage and cardiac hypertrophy pathways are intimately associated with the pathology of myocardial infarction (MI). The protective effects of β-caryophyllene on mitochondrial damage and cardiac hypertrophy pathways in isoproterenol-induced myocardial infarcted rats were investigated. Isoproterenol (100 mg/kg body weight) was administered to induce MI. The ST-segment, QT interval, and T wave were widened, and the QRS complex and P wave were shortened in the electrocardiogram (ECG) and the serum cardiac diagnostic markers and heart mitochondrial lipid peroxidation products, calcium ions, and reactive oxygen species (ROS) were elevated and the heart mitochondrial antioxidants, tricarboxylic acid cycle, and respiratory chain enzymes were lessened in isoproterenol-induced myocardial infarcted rats. The heart mitochondrial damage was noted in the transmission electron microscopic study. The whole heart weight was increased and the subunits of nicotinamide adenine dinucleotide phosphate – oxidase 2 (Nox 2) genes such as cybb and p22-phox and cardiac hypertrophy genes such as atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), β -myosin heavy chain (β-MHC), and actin alpha skeletal muscle-1(ACTA-1) were highly expressed in the rat's heart by reverse transcription-polymerase chain reaction study. The β-caryophyllene (20 mg/kg body weight) pre- and co-treatment orally, daily for 21 days reversed changes in ECG and lessened cardiac diagnostic markers, ROS, and whole heart weight and ameliorated mitochondrial damage and Nox/ANP/BNP/β-MHC/ACTA-1cardiac hypertrophy pathways in isoproterenol-induced myocardial infarcted rats. The observed effects might be due to the antioxidant, anti-mitochondrial damaging, and anti-cardiac hypertrophic mechanisms of β-caryophyllene.

Alpha lipoic acid–loaded electrospun fibrous patch films protect heart in acute myocardial infarction mice by inhibiting oxidative stress

Oxidative stress, characterized by excessive accumulation of reactive oxygen species (ROS), is involved in acute myocardial infarction (AMI)-related pathological processes and vascular reperfusion therapy injury. Alpha lipoic acid (LA) exhibits excellent antioxidant properties, however, its application is limited by inherent characteristics, including rapid clearance and extensive volume distribution. In this study, we hypothesized that scavenging cardiac ROS using adequately delivered LA could promote heart repair. Here, we report a new strategy for dynamic-release LA to treat AMI disease. In particular, this involves using poly(lactic-co-glycolic) (PLGA) copolymers as carriers to form a thin film (LA@PLGA) via electrospinning technology to achieve controlled release of LA, which essentially blocking local ROS production in damaged hearts. The drug-loading capacity and capsulation efficiency of this compound film could be regulated by determining the dose proportions of LA and PLGA. The incubation of LA@PLGA showed strong anti-oxidative activity and anti-apoptosis effect in hydrogen peroxide–administered primary cardiomyocytes. Patching LA@PLGA on the infarcted cardiac surfaces of AMI mice dramatically improved heart functions and reduced cardiac fibrosis throughout ventricular remodeling process. Importantly, the attenuation of detrimental pathologies was observed, including oxidative stress, senescence, DNA damage, cytokine-related processes, apoptosis, and ferroptosis. These results suggest that PLGA-carried LA can reduce ROS damage and restore heart function after myocardial damage, demonstrating a great potential for LA drugs in treating AMI disease.

Columbianadin attenuates doxorubicin-induced cardiac injury, oxidative stress, and apoptosis via Sirt1/FOXO1 signaling pathway.

Oxidative stress and apoptosis contribute to the pathological basis of doxorubicin (DOX)-induced cardiotoxicity. Columbianadin (CBN) is one of the main bioactive constituents isolated from the root of Angelica pubescens. Herein, we intended to explore the potential role and molecular basis of CBN in DOX-induced cardiotoxicity. C57BL/6 mice were subjected to DOX (15 mg/kg/day, i.p.) to generate DOX-induced cardiotoxicity. CBN (10 mg/kg/day, i.p.) was administered for four week following DOX injection. DOX administered markedly dampened cardiac function, increased cardiac injury, excessive reactive oxygen species (ROS) production, and cardiomyocyte loss. These alterations induced by DOX significantly alleviated by CBN treatment. Mechanistically, our results demonstrated that the CBN exerts cardioprotection role against DOX by up-regulating silent information regulator 1 (Sirt1) and decreasing acetylation of forkhead box O1 (FOXO1). Moreover, Sirt1 inhibition with Ex-527 significantly blunt the beneficial effect of CBN on DOX-induced cardiotoxicity, including cardiac dysfunction, ROS, and apoptosis. Collectively, CBN attenuated oxidative stress and cardiomyocyte apoptosis in DOX-induced cardiotoxicity through maintaining Sirt1/FOXO1 signaling pathway. Our results demonstrated that CBN might be used to treat DOX-related cardiotoxicity.

Chemical Characterization of Taif Rose (Rosa damascena) Methanolic Extract and Its Physiological Effect on Liver Functions, Blood Indices, Antioxidant Capacity, and Heart Vitality against Cadmium Chloride Toxicity.

Exposure to cadmium chloride (CdCl2) causes an imbalance in the oxidant status of the body by triggering the release of reactive oxygen species (ROS). This study investigated the effect of Rosa damascena (R. damascena) extract on oxidative stress, hepatotoxicity, and the injured cardiac tissue of male rats exposed to CdCl2. Forty male Wistar albino rats were divided into four groups: the vehicle control (1 mg/kg normal saline), the CdCl2-treated group (5 mg/kg), the R. damascena extract group (100 mg Kg), and the combination of CdCl2 and R. damascena extract group. Male rats exposed to CdCl2 showed multiple significant histopathological changes in the liver and heart, including inflammatory cell infiltration and degenerative alterations. Successive exposure to CdCl2 elevated the levels of hepatic and cardiac reactive oxygen species (ROS), malondialdehyde (MDA), tumour necrosis factor-alpha) (TNF-α) and interleukin -6 (IL-6) and decreased antioxidant defences. The extracts significantly increased the levels of glutathione, superoxide dismutase (SOD), and catalase (CAT), whereas it dramatically decreased the levels of lipid peroxidation (LPO), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and the mRNA of TNF-α and IL-6. R. damascena administration prevented liver and heart injury; suppressed excessive ROS generation, LPO, and inflammatory responses; and enhanced antioxidant defences. In addition, R. damascena upregulated the mRNA of TNF-α and IL-6 in CdCl2-administered male rats. In conclusion, R. damascena modulated the oxidative stress and inflammation induced by CdCl2. The hepatic and cardiac tissue damage and histopathological alterations resulting from the CdCl2-induced oxidative stress were counteracted by the administration of R. damascena extracts. R. damascena enhanced antioxidant defence enzymes in male rats.

Sacubitril/valsartan ameliorates doxorubicin-induced cardiomyocyte toxicity through inhibiting oxidative stress in rats

Abstract Background Doxorubicin (DOX)-based chemotherapy induces cardiotoxicity, which is considered the main limitation of its clinical application. Purpose The present study investigated the potential protective effect of sacubitril/valsartan, an angiotensin receptor–neprilysin inhibitor, against DOX-induced cardiotoxicity in rats and H9c2 cells, and whether the underlying mechanism for any such protection involves its antioxidant activity. Methods Male Sprague-Dawley rats were randomly divided into four groups: DOX (1.5 mg/kg/day intraperitoneally for 10 days), DOX+valsartan (31 mg/kg/day by gavage from day 1 to day 18), DOX+sacubitril/valsartan (68 mg/kg/day by gavage from day 1 to day 18), and control (saline intraperitoneally for 10 days). There were 15 rats in each group. At the end of the treatment period, samples were collected and analysed. Cardiac function, tissue morphology, and reactive oxygen species (ROS) were evaluated in rats. Serum levels of Malondialdehyde (MDA) and cardiac troponin T were also measured. Mitochondrial ROS production and cell viability were evaluated in H9c2 cells. Results DOX-induced cardiac dysfunction was not prevented by valsartan and sacubitril/valsartan in this model. However, the serum level of cardiac troponin T on day 18 was increased in the DOX group (0.046±0.006 ng/mL, p<0.01 vs. control) and significantly reduced in the DOX+sacubitril/valsartan group (0.039±0.007 ng/mL, p=0.03 vs. DOX), but not in the DOX+valsartan group (0.046±0.005 ng/mL, p=1.00 vs. DOX). Regarding the effect of sacubitril/valsartan on fibrosis in rat myocardium, Masson's trichrome staining showed increased intestinal fibrosis in the DOX group compared to that in the control group (1.35±0.07% and 0.49±0.04%, p<0.01) and significantly decreased intestinal fibrosis in the DOX+sacubitril/valsartan group (1.08±0.08%), but not in the DOX+ valsartan group (1.15±0.05%) compared to that in the DOX group (p=0.01 and p=0.15, respectively). The fluorescence intensity of dihydroethidium as a measure of ROD production in left ventricle, which was increased in the DOX group (1.56±0.07), was significantly reduced in the DOX+sacubitril/valsartan group (1.44±0.05, p=0.03), but not in the DOX+valsartan group (1.29±0.06, p=1.00). On day 11, the serum MDA level, which was increased in the DOX group, was significantly reduced in the DOX+ sacubitril/valsartan group (p=0.02), but not in the DOX+ valsartan group (p=0.75). In H9c2 cells, sacubitril/valsartan reduced DOX-induced mitochondrial ROS generation by 25%, which was more marked than valsartan-induced ROS generation (p<0.01 and p=0.01, respectively). Sacubitril/valsartan improved cell viability more markedly than valsartan. Thus, DOX-induced cytotoxicity in H9c2 cells was improved by sacubitril/valsartan, but not valsartan. Conclusions Sacubitril/valsartan protected rat hearts from DOX-induced cardiotoxicity in vivo and in vitro by decreasing oxidative stress. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): This work was supported by Novartis Pharma K.K.

Blockade of the innate immune checkpoint CD47 decreases infarct size by modulation of oxidative stress and immune response

Abstract Background Myocardial infarction (MI) is the leading cause of death worldwide. Following ischemia/reperfusion (I/R) injury a precisely controlled immune response is necessary for preservation of cardiac integrity. In its course, immune cells interact with dead and damaged cells via a variety of cell surface molecules. One such interaction revolves around signal regulatory protein α (SIRPα) on myeloid cells and ubiquitously expressed CD47, which inhibits phagocytosis and was thus termed an innate immune checkpoint. Inhibition of CD47 via antibodies was shown to be protective in other I/R injury of eg liver and kidney, mostly by modulation of nitric oxide (NO) related pathways. Whether it is also beneficial in myocardial I/R injury remains to be seen. Methods and results We determined I/R injury size in murine hearts after anti-CD47 treatment using the triphenyl tetrazolium chloride (TTC)/Evans blue test and found decreased TTC negative per area at risk (AAR) at 24 h of reperfusion when compared to IgG antibody treated mice. Likewise ejection fraction was higher and plasma cardiac Troponin I (cTNI) levels were lower in anti-CD47 treated animals at the same time point. We further studied immune cell populations using flow cytometry, which revealed similar levels of neutrophils at 24 h of reperfusion in both anti-CD47 and control groups. To investigate this paradox, we deployed cutting edge light sheet fluorescence microscopy (LSFM) to simultaneously measure I/R injury size and immune cell levels and indeed found a higher ratio of neutrophils per injured area in CD47 treated mice. Furthermore, in these animals neutrophil populations were localized outside the injured area rather than only just inside, as was the case in the control group. We further measured cardiac reactive oxygen species (ROS) concentration and found ROS levels to be slightly decreased after CD47 injections following I/R. In contrast to results from other I/R injury models, we could not find an influence of anti-CD47 treatment on nitrate/nitrite/NO pathways. Conclusion Anti-CD47 treatment was shown to be protective in various I/R injury models. We could also demonstrate reduced infarct sizes after 24 h of reperfusion. This was not associated with decreased levels of neutrophils, which also located only outside of the injured area. Whether this is beneficial for the long term outcome, remains to be investigated. Nevertheless CD47 blockade presents as a highly novel and promising approach to AMI treatment and warrants further research. Funding Acknowledgement Type of funding sources: None.

Cardiomyocyte-specific miR-100 overexpression preserves heart function under pressure overload in mice and diminishes fatty acid uptake as well as ROS production by direct suppression of Nox4 and CD36.

MicroRNAs are key regulators of the cardiac response to injury. MiR-100 has recently been suggested to be involved in different forms of heart failure, but functional studies are lacking. In the present study, we examined the impact of transgenic miR-100 overexpression on cardiac structure and function during physiological aging and pathological pressure-overload-induced heart failure in mice after transverse aortic constriction surgery. MiR-100 was moderately upregulated after induction of pressure overload in mice. While in our transgenic model the cardiomyocyte-specific overexpression of miR-100 did not result in an obvious cardiac phenotype in unchallenged mice, the transgenic mouse strain exhibited less left ventricular dilatation and a higher ejection fraction than wildtype animals, demonstrating an attenuation of maladaptive cardiac remodeling by miR-100. Cardiac transcriptome analysis identified a repression of several regulatory genes related to cardiac metabolism, lipid peroxidation, and production of reactive oxygen species (ROS) by miR-100 overexpression, possibly mediating the observed functional effects. While the modulation of ROS-production seemed to be indirectly affected by miR-100 via Alox5-and Nox4-downregulation, we demonstrated that miR-100 induced a direct repression of the scavenger protein CD36 in murine hearts resulting in a decreased uptake of long-chain fatty acids and an alteration of mitochondrial respiratory function with an enhanced glycolytic state. In summary, we identified miR-100 as a modulator of cardiac metabolism and ROS production without an apparent cardiac phenotype at baseline but a protective effect under conditions of pressure-overload-induced cardiac stress, providing new insight into the mechanisms of heart failure.

KLF15 Regulates Oxidative Stress Response in Cardiomyocytes through NAD.

KLF15 has recently emerged as a central regulator of metabolism. Although its connection to oxidative stress has been suspected, there has not been any study to date that directly demonstrates the molecular link. In this study, we sought to determine the role of KLF15 in cardiac oxidative stress. We found that KLF15 deficiency in the heart is associated with increased oxidative stress. Acute deficiency of KLF15 in neonatal rat ventricular myocytes (NRVMs) leads to the defective clearance of reactive oxygen species (ROS) and an exaggerated cell death following a variety of oxidative stresses. Mechanistically, we found that KLF15 deficiency leads to reduced amounts of the rate-limiting NAD+ salvage enzyme NAMPT and to NAD+ deficiency. The resultant SIRT3-dependent hyperacetylation and the inactivation of mitochondrial antioxidants can be rescued by MnSOD mimetics or NAD+ precursors. Collectively, these findings suggest that KLF15 regulates cardiac ROS clearance through the regulation of NAD+ levels. Our findings establish KLF15 as a central coordinator of cardiac metabolism and ROS clearance.

Visnagin prevents isoproterenol-induced myocardial injury by attenuating oxidative stress and inflammation and upregulating Nrf2 signaling in rats.

Oxidative tissue injury and inflammatory responses play major roles in cardiovascular diseases and heart failure. Visnagin (VIS) is a natural bioactive component of Ammi visnaga, with promising radical scavenging and anti-inflammatory activities. This study explored the protective effect of VIS against isoproterenol (ISO)-induced acute myocardial injury and oxidative stress in rats. VIS was supplemented for 14 days, and the rats received ISO (100 mg/kg) twice at an interval of 24 h. ISO-induced myocardial injury was characterized by elevated serum CK-MB, LDH, and troponin-I associated with increased heart weightand several histopathological changes. ISO increased reactive oxygen species (ROS), malondialdehyde (MDA), NF-κB p65, TNF-α, IL-6, and decreased glutathione and antioxidant enzymes in rats' hearts. VIS prevented myocardial injury and ameliorated the cardiac function markers, ROS, MDA, NF-κB p65, and pro-inflammatory cytokines in ISO-intoxicated rats. In addition, VIS decreased Bax mRNA and caspases, and upregulated Nrf2, HO-1, Bcl-2, and PPARγ. Molecular docking simulations revealed the binding method of VIS to NF-κB, Keap1, and PPARγ. In conclusion, VIS protects against ISO-induced acute myocardial injury by attenuating oxidative tissue injury and reducing key inflammatory and apoptosis markers. In vivo and in silico results showed that activation of Nrf2/HO-1 signaling and PPARγ mediates the cardioprotective effect of VIS.

Effects of aerobic interval training on myocardial oxidative stress and inflammation in rats with myocardial infarction and its mechanism

Objective: The present study was to determine the effects of aerobic interval training (AIT) on the expressions of SIRT1, Nox4 and inflammatory factor in the heart of rats with myocardial infarction (MI). Methods: Male Sprague Dawley rats were randomly divided into sham-operated group (C), sedentary MI group (MI) and MI with AIT group (ME) (n=10). The MI model was established by ligation the left anterior descending coronary artery. Rats in C groups were subjected to the same surgery, but only threaded and not ligated. After surgery 1 week, rats in ME groups took adaptability training for 1 week, and then subjected to 4 weeks treadmill exercise training. After training, the hearts were collected for histological observation. The level of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in heart was assessed by ultraviolet spectrophotometry. The activity of lactate dehydrogenase (LDH) was determined by enzyme linked immunosorbent assay. The expression of sirtuin1 (SIRT1) mRNA was examined by real-time quantitative polymerase chain reaction (RT-qPCR). The protein expressions of SIRT1, NADPH oxidase 4 (Nox4), tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) were detected by Western blotting. The levels of reactive oxygen species (ROS) were detected by dihydroethidium (DHE) staining. Results: Compared with the C group, the expression level of cardiac Nox4 protein was increased (P＜0.01), the level of MDA, activity of LDH and the level of ROS were increased significantly (P＜0.01), and the expressions of TNF-α and IL-1β protein were augmented in the heart of rats with MI (P＜0.01). However, the expressions of SIRT1 mRNA and protein and the activity of SOD were obviously decreased in MI group (P＜0.01). Furthermore, compared with the MI group, AIT increased the expressions of SIRT1 mRNA and protein and the activity of SOD in the heart of ME group (P＜0.01); Meanwhile, the expressions of cardiac Nox4, MDA level, LDH activity and ROS level were diminished in ME group (P＜0.01) as well as the decreased expressions of TNF-α and IL-1β protein (P＜0.01). SIRT1 expression was negatively related to the expressions of NOX4 and ROS. Conclusion: AIT obviously inhibited myocardial oxidative stress and inflammatory reaction, improved cardiac function in rats with MI, and the mechanism was closely related to the activation of SIRT1-Nox4-ROS signaling pathway.

Preconditioning with Short-term Dietary Restriction Attenuates Cardiac Oxidative Stress and Hypertrophy Induced by Chronic Pressure Overload.

Left ventricular (LV) hypertrophy and associated heart failure are becoming a more prevalent and critical public health issue with the aging of society, and are exacerbated by reactive oxygen species (ROS). Dietary restriction (DR) markedly inhibits senescent changes; however, prolonged DR is difficult. We herein investigated whether preconditioning with short-term DR attenuates chronic pressure overload-induced cardiac hypertrophy and associated oxidative stress. Male c57BL6 mice were randomly divided into an ad libitum (AL) diet or 40% restricted diet (DR preconditioning, DRPC) group for 2 weeks prior to ascending aortic constriction (AAC), and all mice were fed ad libitum after AAC surgery. Two weeks after surgery, pressure overload by AAC increased LV wall thickness in association with LV diastolic dysfunction and promoted myocyte hypertrophy and cardiac fibrosis in the AL+AAC group. Oxidative stress in cardiac tissue and mitochondria also increased in the AL+AAC group in association with increments in cardiac NADPH oxidase-derived and mitochondrial ROS production. LV hypertrophy and associated cardiac dysfunction and oxidative stress were significantly attenuated in the DRPC+AAC group. Moreover, less severe mitochondrial oxidative damage in the DRPC+AAC group was associated with the suppression of mitochondrial permeability transition and cardiac apoptosis. These results indicate that chronic pressure overload-induced cardiac hypertrophy in association with cardiac and mitochondrial oxidative damage were attenuated by preconditioning with short-term DR.

Vascular and Cardiac Oxidative Stress and Inflammation as Targets for Cardioprotection

Cardiac and vascular diseases are often associated with increased oxidative stress and inflammation, and both may contribute to the disease progression. However, successful applications of antioxidants in the clinical setting are very rare and specific anti-inflammatory therapeutics only emerged recently. Reasons for this rely on the great diversity of oxidative stress and inflammatory cells that can either act as cardioprotective or cause tissue damage in the heart. Recent large-scale clinical trials found that highly specific anti-inflammatory therapies using monoclonal antibodies against cytokines resulted in lower cardiovascular mortality in patients with pre-existing atherosclerotic disease. In addition, unspecific antiinflammatory medication and established cardiovascular drugs with pleiotropic immunomodulatory properties such as angiotensin converting enzyme (ACE) inhibitors or statins have proven beneficial cardiovascular effects. Normalization of oxidative stress seems to be a common feature of these therapies, which can be explained by a close interaction/crosstalk of the cellular redox state and inflammatory processes. In this review, we give an overview of cardiac reactive oxygen species (ROS) sources and processes of cardiac inflammation as well as the connection of ROS and inflammation in ischemic cardiomyopathy in order to shed light on possible cardioprotective interventions.

Inhibiting Cardiac Mitochondrial Fatty Acid Oxidation Attenuates Myocardial Injury in a Rat Model of Cardiac Arrest.

Mitochondrial fatty acid oxidation (FAO) is involved in myocardial damage after cardiopulmonary resuscitation (CPR). This study is aimed at investigating the effect of inhibiting mitochondrial FAO on myocardial injury and the underlying mechanisms of postresuscitation myocardial dysfunction. Rats were induced, subjected to 8 min of ventricular fibrillation, and underwent 6 min of CPR. Rats with return of spontaneous circulation (ROSC) were randomly divided into the Sham group, CPR group, and CPR + Trimetazidine (TMZ) group. Rats in the CPR + TMZ group were administered TMZ (10 mg/kg) at the onset of ROSC via the right external jugular vein, while rats in the CPR group were injected with equivalent volumes of vehicle. The sham rats were only administered equivalent volumes of vehicle. We found that the activities of enzymes related to cardiac mitochondrial FAO were partly improved after ROSC. TMZ, as a reversible inhibitor of 3-ketoacyl CoA thiolase, inhibited myocardial mitochondrial FAO after ROSC. In the CPR + TMZ group, the levels of mitochondrial injury in cardiac tissue were alleviated following attenuated myocardial damage and oxidative stress after ROSC. In addition, the disorder of cardiac mitochondrial metabolism was ameliorated, and specifically, the superfluous succinate related to mitochondrial reactive oxygen species (ROS) generation was decreased by inhibiting myocardial mitochondrial FAO with TMZ administration after ROSC. In conclusion, in the early period after ROSC, inhibiting cardiac mitochondrial FAO attenuated excessive cardiac ROS generation and preserved myocardial function, probably by alleviating the dysfunction of cardiac mitochondrial metabolism in a rat model of cardiac arrest.