Hypertrophic preconditioning cardioprotection after myocardial ischaemia/reperfusion injury involves ALDH2-dependent metabolism modulation

ALDH2 delays ventricular pressure overload-induced heart failure by promoting cardiomyocyte proliferation in mice

The adult mammalian heart is a terminally differentiated organ in which the majority of cardiomyocytes are in a state of cell cycle arrest, rendering them incapable of effectively proliferating to replace damaged cells. ALDH2, an enzyme known for alleviating oxidative stress, has been demonstrated to play a critical role in cardiac protection. However, whether ALDH2 regulates cardiomyocyte proliferation has not been conclusively established. We found that activation of ALDH2 activity significantly promotes cardiomyocyte proliferation and extends the proliferation window during early postnatal development in neonatal mice. Furthermore, administration of Alda-1 to activate ALDH2 in adult mice subjected to transverse aortic constriction markedly enhanced cardiomyocyte proliferation and delayed the onset of pressure overload-induced heart failure. In summary, our findings identify ALDH2 as a potential target for regulating cardiomyocyte proliferation and offer a novel therapeutic approach for treating heart failure.

Mechanisms and preventive measures of ALDH2 in ischemia‑reperfusion injury: Ferroptosis as a novel target (Review)

Ischemia‑reperfusion injury (IRI) refers to tissue or organ damage that occurs following a period of inadequate blood supply (ischemia) followed by restoration of blood flow (reperfusion) within a short time frame. This phenomenon is prevalent in clinical conditions such as cardiovascular and cerebrovascular disease, organ transplantation and stroke. Despite its frequency, effective therapeutic strategies to mitigate IRI remain elusive in clinical practice, underscoring the need for a deeper understanding of its molecular mechanisms. Aldehyde dehydrogenase 2 (ALDH2), a key enzyme in alcohol metabolism, serves a role in alleviating oxidative stress and cell damage during IRI by modulating oxidative stress, decreasing apoptosis and inhibiting inflammatory responses. ALDH2 exerts protective effects by detoxifying reactive aldehydes, thereby preventing lipid peroxidation and maintaining cellular homeostasis. Furthermore, ferroptosis, a regulated form of cell death driven by iron accumulation and subsequent lipid peroxidation, is a key process in IRI. However, the precise role of ALDH2 in modulating ferroptosis during IRI remains incompletely understood. Although there is an interaction between ALDH2 activity and ferroptosis, the underlying mechanisms have yet to be clarified. The present review examines the role of ALDH2 and ferroptosis in IRI and the potential regulatory influence of ALDH2 on ferroptosis mechanisms, as well as potential targeting of ALDH2 and ferroptosis for IRI treatment and prevention. By elucidating the complex interplay between ALDH2 and ferroptosis, the present review aims to provide new insights for the development of innovative therapeutic strategies to mitigate ischemic tissue damage and improve clinical outcomes.

Bruton tyrosine kinase promotes wound healing after myocardial infarction by inhibiting the transcription of u-PA

BACKGROUNDS

Bruton tyrosine kinase (BTK), which is highly expressed in immune cells, plays a critical role in regulating the function of macrophages. A growing body of evidence has demonstrated that the accumulation of macrophages in cardiac tissue after myocardial infarction (MI) significantly affects wound healing and ventricular remodeling during the early phase of repair after MI. However, the role of BTK in cardiac repair post-MI, especially in macrophage-mediated repair, remains unclear.

METHODS

MI was induced by permanent left anterior descending (LAD) artery ligation in wild-type (WT) mice and macrophage-specific BTK-knockout (BTKMAC-KO) mice. Expression of BTK and phosphorylated BTK were assessed by western blotting. Then, RNA sequencing and ChIP-qPCR assay were performed to explore potential BTK targets and transcriptional regulatory sites.

RESULTS

BTK, which was mainly expressed in macrophages, was upregulated in mice after MI. Compared with WT mice, BTKMAC-KO mice had significantly greater mortality due to heart rupture, reduced wall thickness and severe impairment of left ventricular (LV) function after MI. In addition, increased matrix metalloproteinase-9 (MMP-9) expression and decreased α-SMA and collagen expression were observed in BTKMAC-KO mice after MI. Further experiments revealed that BTK deficiency in macrophages reduces the expression of VEGF and impairs angiogenesis after MI. By RNA sequencing, we found that Nf-kB family genes, as well as the urokinase-type plasminogen activator (uPA), were significantly upregulated in BTK-deficient macrophages. By ChIP-qPCR analysis, we confirmed that uPA was transcriptionally activated by the Nf-kB p65 subunit. Finally, the application of plasminogen activator inhibitor-1 (PAI-1), an uPA inhibitor, markedly protected against cardiac rupture, lowered the mortality rate, and improved cardiac function by increasing collagen deposition and promoting tissue healing in BTKMAC-KO mice after MI.

CONCLUSIONS

The present study identifies PAI-1 as a novel cardioprotective agent for cardiac repair post-MI that increases collagen deposition and promotes tissue healing. A therapeutic strategy targeting BTK may be a promising treatment for cardiac repair post-MI.

Gualou Xiebai Banxia Decoction suppresses cardiomyocyte apoptosis in mice after myocardial infarction through activation of acetaldehyde dehydrogenase 2

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiac apoptosis has been reported to be involved in the development of Heart failure (HF) after Myocardial infarction (MI). As a traditional Chinese medicine with cardioprotective properties, Gualou Xiebai Banxia Decoction (GXBD) is therapeutically effective in treating MI. However, whether GXBD regulates cardiac apoptosis in HF after MI remains unknown, and the underlying mechanisms still unclear.

AIM OF THE STUDY

This study aimed to explore the effects and potential mechanisms of GXBD on cardiac apoptosis after MI.

MATERIALS AND METHODS

The MI model was constructed by ligating the left anterior descending coronary artery (LAD) in mice. The cardioprotective effects of GXBD were determined by echocardiography, masson staining, and haematoxylin and eosin (HE) staining. Bioinformatics analysis and network Pharmacology were used to explore the underlying molecular mechanisms of GXBD in MI. The effects of GXBD on cardiomyocyte apoptosis as well as the ALDH2 were examined by TUNEL staining, Immunohistochemistry (IHC), and Western blot (WB). Additionally, the effects of GXBD on oxidative stress, apoptosis and the ALDH2 in H9c2 cells were investigated using reactive oxygen species (ROS) detection, Hoechst33342/PI stainingand and WB. Moreover, the effects of suppressing and overexpressing ALDH2 in H9c2 cells were further examined.

RESULTS

Target prediction analysis showed that ALDH2 was a key target of GXBD which could ameliorate myocardial infarction. GXBD dose-dependently reduced cardiomyocyte apoptosis and ventricular dysfunction. In vivo experiments, GXBD activated ALDH2 enzymatic activity and inhibited the expression levels of Bax, Bcl-2, Cleaved Caspase 3, and Caspase 9. In vitro experiments, GXBD inhibited apoptosis in H9c2 cells. The inhibitory effects of GXBD on these were at least partially attributed to ALDH2 activation while silencing of ALDH2 significantly reversed these inhibitory effects of GXBD.

CONCLUSION

GXBD exerts inhibitory effects on cardiomyocyte apoptosis in mice after MI and suppresses H9c2 cells oxidative stress and apoptosis through activation of the enzyme activity of ALDH2.

Advances in the study of exosomes in cardiovascular diseases

BACKGROUND

Cardiovascular disease (CVD) has been the leading cause of death worldwide for many years. In recent years, exosomes have gained extensive attention in the cardiovascular system due to their excellent biocompatibility. Studies have extensively researched miRNAs in exosomes and found that they play critical roles in various physiological and pathological processes in the cardiovascular system. These processes include promoting or inhibiting inflammatory responses, promoting angiogenesis, participating in cell proliferation and migration, and promoting pathological progression such as fibrosis.

AIM OF REVIEW

This systematic review examines the role of exosomes in various cardiovascular diseases such as atherosclerosis, myocardial infarction, ischemia-reperfusion injury, heart failure and cardiomyopathy. It also presents the latest treatment and prevention methods utilizing exosomes. The study aims to provide new insights and approaches for preventing and treating cardiovascular diseases by exploring the relationship between exosomes and these conditions. Furthermore, the review emphasizes the potential clinical use of exosomes as biomarkers for diagnosing cardiovascular diseases.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Exosomes are nanoscale vesicles surrounded by lipid bilayers that are secreted by most cells in the body. They are heterogeneous, varying in size and composition, with a diameter typically ranging from 40 to 160 nm. Exosomes serve as a means of information communication between cells, carrying various biologically active substances, including lipids, proteins, and small RNAs such as miRNAs and lncRNAs. As a result, they participate in both physiological and pathological processes within the body.

ITFG2, an immune-modulatory protein, targets ATP 5b to maintain mitochondrial function in myocardial infarction

ITFG2, as an immune-modulatory intracellular protein that modulate the fate of B cells and negatively regulates mTORC1 signaling. ITFG2 is highly expressed in the heart, but its pathophysiological function in heart disease is unclear. In this study, we found that in MI mice, overexpression of ITFG2 via an AAV9 vector significantly reduced the infarct size and ameliorated cardiac function. Knockdown of endogenous ITFG2 by shRNA partially aggravated ischemia-induced cardiac dysfunction. In cardiac-specific ITFG2 transgenic (TG) mice, myocardial infarction size was smaller, eject fraction (EF) and fractional shortening (FS) was higher compared to those in wild-type (WT) mice, suggesting ITFG2 reversed cardiac dysfunction induced by MI. In hypoxic neonatal cardiomyocytes (NMCMs), overexpression of ITFG2 maintained mitochondrial function by increasing intracellular ATP production, reducing ROS levels, and preserving the mitochondrial membrane potential (MMP). Overexpression of ITFG2 reversed the mitochondrial respiratory dysfunction in NMCMs induced by hypoxia. Knockdown of endogenous ITFG2 by siRNA did the opposite. Mechanism, ITFG2 formed a complex with NEDD4-2 and ATP 5b and inhibited the binding of NEDD4-2 with ATP 5b leading to the reduction ubiquitination of ATP 5b. Our findings reveal a previously unknown ability of ITFG2 to protect the heart against ischemic injury by interacting with ATP 5b and thereby regulating mitochondrial function. ITFG2 has promise as a novel strategy for the clinical management of MI.

ALDH2 polymorphism and myocardial infarction: From alcohol metabolism to redox regulation

Acute myocardial infarction (AMI) remains a leading cause of death worldwide. Increased formation of reactive oxygen species (ROS) during the early reperfusion phase is thought to trigger lipid peroxidation and disrupt redox homeostasis, leading to myocardial injury. Whilst the mitochondrial enzyme aldehyde dehydrogenase 2 (ALDH2) is chiefly recognised for its central role in ethanol metabolism, substantial experimental evidence suggests an additional cardioprotective role for ALDH2 independent of alcohol intake, which mitigates myocardial injury by detoxifying breakdown products of lipid peroxidation including the reactive aldehydes, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE). Epidemiological evidence suggests that an ALDH2 mutant variant with reduced activity that is highly prevalent in the East Asian population increases AMI risk. Additional studies have uncovered a strong association between coronary heart disease and this ALDH2 mutant variant. It appears this enzyme polymorphism (in particular, in ALDH2*2/2 carriers) has the potential to have wide-ranging effects on thiol reactivity, redox tone and therefore numerous redox-related signaling processes, resilience of the heart to cope with lifestyle-related and environmental stressors, and the ability of the whole body to achieve redox balance. In this review, we summarize the journey of ALDH2 from a mitochondrial reductase linked to alcohol metabolism, via pre-clinical studies aimed at stimulating ALDH2 activity to reduce myocardial injury to clinical evidence for its protective role in the heart.

Myocardial reperfusion injury exacerbation due to ALDH2 deficiency is mediated by neutrophil extracellular traps and prevented by leukotriene C4 inhibition

BACKGROUND AND AIMS

The Glu504Lys polymorphism in the aldehyde dehydrogenase 2 (ALDH2) gene is closely associated with myocardial ischaemia/reperfusion injury (I/RI). The effects of ALDH2 on neutrophil extracellular trap (NET) formation (i.e. NETosis) during I/RI remain unknown. This study aimed to investigate the role of ALDH2 in NETosis in the pathogenesis of myocardial I/RI.

METHODS

The mouse model of myocardial I/RI was constructed on wild-type, ALDH2 knockout, peptidylarginine deiminase 4 (Pad4) knockout, and ALDH2/PAD4 double knockout mice. Overall, 308 ST-elevation myocardial infarction patients after primary percutaneous coronary intervention were enrolled in the study.

RESULTS

Enhanced NETosis was observed in human neutrophils carrying the ALDH2 genetic mutation and ischaemic myocardium of ALDH2 knockout mice compared with controls. PAD4 knockout or treatment with NETosis-targeting drugs (GSK484, DNase1) substantially attenuated the extent of myocardial damage, particularly in ALDH2 knockout. Mechanistically, ALDH2 deficiency increased damage-associated molecular pattern release and susceptibility to NET-induced damage during myocardial I/RI. ALDH2 deficiency induced NOX2-dependent NETosis via upregulating the endoplasmic reticulum stress/microsomal glutathione S-transferase 2/leukotriene C4 (LTC4) pathway. The Food and Drug Administration-approved LTC4 receptor antagonist pranlukast ameliorated I/RI by inhibiting NETosis in both wild-type and ALDH2 knockout mice. Serum myeloperoxidase-DNA complex and LTC4 levels exhibited the predictive effect on adverse left ventricular remodelling at 6 months after primary percutaneous coronary intervention in ST-elevation myocardial infarction patients.

CONCLUSIONS

ALDH2 deficiency exacerbates myocardial I/RI by promoting NETosis via the endoplasmic reticulum stress/microsomal glutathione S-transferase 2/LTC4/NOX2 pathway. This study hints at the role of NETosis in the pathogenesis of myocardial I/RI, and pranlukast might be a potential therapeutic option for attenuating I/RI, particularly in individuals with the ALDH2 mutation.

Aldehyde dehydrogenase 2 serves as a key cardiometabolic adaptation regulator in response to plateau hypoxia in mice

High-altitude heart disease (HAHD) is a complex pathophysiological condition related to systemic hypobaric hypoxia in response to transitioning to high altitude. Hypoxia can cause myocardial metabolic dysregulation, leading to an increased risk of heart failure and sudden cardiac death. Aldehyde dehydrogenase 2 (ALDH2) could regulate myocardial energy metabolism and plays a protective role in various cardiovascular diseases. This study aims to determine the effects of plateau hypoxia (PH) on cardiac metabolism and function, investigate the associated role of ALDH2, and explore potential therapeutic targets. We discovered that PH significantly reduced survival rate and cardiac function. These effects were exacerbated by ALDH2 deficiency. PH also caused a shift in the myocardial fuel source from fatty acids to glucose; ALDH2 deficiency impaired this adaptive metabolic shift. Untargeted/targeted metabolomics and transmission electron microscopy revealed that ALDH2 deficiency promoted myocardial fatty-acid deposition, leading to enhanced fatty-acid transport, lipotoxicity and mitochondrial dysfunction. Furthermore, results showed that ALDH2 attenuated PH-induced impairment of adaptive metabolic programs through 4-HNE/CPT1 signaling, and the CPT1 inhibitor etomoxir significantly ameliorated ALDH2 deficiency-induced cardiac impairment and improved survival in PH mice. Together, our data reveal ALDH2 acts as a key cardiometabolic adaptation regulator in response to PH. CPT1 inhibitor, etomoxir, may attenuate ALDH2 deficiency-induced effects and improved cardiac function in response to PH.

Remote Ischemic Conditioning Mediates Cardio-protection After Myocardial Ischemia/Reperfusion Injury by Reducing 4-HNE Levels and Regulating Autophagy via the ALDH2/SIRT3/HIF1α Signaling Pathway

Remote ischemic conditioning (RIC) can be effectively applied for cardio-protection. Here, to clarify whether RIC exerts myocardial protection via aldehyde dehydrogenase 2 (ALDH2), we established a myocardial ischemia/reperfusion (I/R) model in C57BL/6 and ALDH2 knockout (ALDH2-KO) mice and treated them with RIC. Echocardiography and single-cell contraction experiments showed that RIC significantly improved myocardial function and alleviated I/R injury in C57BL/6 mice but did not exhibit its cardioprotective effects in ALDH2-KO mice. TUNEL, Evan's blue/triphenyl tetrazolium chloride, and reactive oxygen species (ROS) assays showed that RIC's effect on reducing myocardial cell apoptosis, myocardial infarction area, and ROS levels was insignificant in ALDH2-KO mice. Our results showed that RIC could increase ALDH2 protein levels, activate sirtuin 3 (SIRT3)/hypoxia-inducible factor 1-alpha (HIF1α), inhibit autophagy, and exert myocardial protection. This study revealed that RIC could exert myocardial protection via the ALDH2/SIRT3/HIF1α signaling pathway by reducing 4-HNE secretion.

Cancer Treatment-Related Complications in Patients With Hypertrophic Cardiomyopathy

OBJECTIVE

To describe the potential clinical cardiotoxicity of oncological treatments in a cohort of consecutive patients with hypertrophic cardiomyopathy (HCM), systematically followed-up at two national referral centers for HCM. Cardiotoxicity relates to the direct effects of cancer-related treatment on heart function, commonly presenting as left ventricular contractile dysfunction. However, limited data are available regarding cardiotoxic effects on HCM as most studies have not specifically analyzed the effects of oncological treatment in HCM populations. This gap in knowledge may lead to unjustified restriction of HCM patients from receiving curative cancer treatments.

METHODS

We retrospectively analyzed clinical and instrumental data of all consecutive HCM patients who underwent oncological treatment between January 2000 and December 2020 collected in a centralized database.

RESULTS

Of 3256 HCM patients, 121 (3.7%) had cancer; 110 (90.9%) underwent oncological surgery, 45 (37.2%) received chemotherapy, and 22 (18.2%) received chest radiation therapy (cRT). After a median follow-up of 5.2 years (Q1-Q3: 2-13 years) from oncological diagnosis, 32 patients died. The cumulative survival at 5 years was 79.9%. The cause of death was mainly attributed to the oncological condition, whereas four patients died of sudden cardiac death without receiving previous chemotherapy or cRT. No patient interrupted or reduced the dose of oncological treatment due to cardiac dysfunction. No sustained ventricular tachyarrhythmia was induced by chemotherapy or radiation therapy.

CONCLUSION

Cancer treatment was well tolerated in HCM patients. In our consecutive series, none died of cardiovascular complications induced by chemotherapy or cRT and they did not require interruption or substantial treatment tapering due to cardiovascular toxic effects. Although a multidisciplinary evaluation is necessary and regimens must be tailored individually, the diagnosis of HCM per se should not be considered a contraindication to receive optimal curative cancer treatment.

Metabolic adaptations in pressure overload hypertrophic heart

This review article offers a detailed examination of metabolic adaptations in pressure overload hypertrophic hearts, a condition that plays a pivotal role in the progression of heart failure with preserved ejection fraction (HFpEF) to heart failure with reduced ejection fraction (HFrEF). The paper delves into the complex interplay between various metabolic pathways, including glucose metabolism, fatty acid metabolism, branched-chain amino acid metabolism, and ketone body metabolism. In-depth insights into the shifts in substrate utilization, the role of different transporter proteins, and the potential impact of hypoxia-induced injuries are discussed. Furthermore, potential therapeutic targets and strategies that could minimize myocardial injury and promote cardiac recovery in the context of pressure overload hypertrophy (POH) are examined. This work aims to contribute to a better understanding of metabolic adaptations in POH, highlighting the need for further research on potential therapeutic applications.

The Binding of HSPA8 and Mitochondrial ALDH2 Mediates Oxygen-Glucose Deprivation-Induced Fibroblast Senescence

Cellular senescence refers to the permanent and irreversible cessation of the cell cycle. Recently, it has gained significant interest as a promising target for preventing cardiovascular diseases. Aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial enzyme that has been closely linked with an increased risk of cardiovascular diseases. In this study, bioinformatics analysis revealed that the signaling pathway for fibroblast senescence is significantly activated in mice after myocardial infarction (MI), and that ALDH2 might be a crucial molecule responsible for inducing this change. Therefore, we created an NIH3T3 fibroblast cell line oxygen-glucose deprivation (OGD) model to replicate the conditions of MI in vitro. We further revealed that decreased ALDH2 enzyme activity is a critical factor that affects fibroblast senescence after OGD, and the activation of ALDH2 can improve the mitochondrial damage caused by OGD. We identified Heat Shock 70-kDa Protein 8 (HSPA8) as an interacting protein of ALDH2 through co-immunoprecipitation (Co-IP) and mass spectrometry (MS) detection. Subsequently, our studies showed that HSPA8 translocates to the mitochondria after OGD, potentially binding to ALDH2 and inhibiting its enzyme activity. By transfecting siRNA to inhibit HSPA8 expression in cells, it was found that ALDH2 enzyme activity can be significantly increased, and the senescence characteristics induced by OGD in NIH3T3 cells can be improved. In conclusion, the data from this study suggest that HSPA8, in conjunction with ALDH2, could regulate fibroblast senescence after oxygen-glucose deprivation, providing a new direction and foundation for effectively intervening in fibroblast senescence after myocardial infarction.

Monocarboxylate transporter 4 protects against myocardial ischemia/reperfusion injury by inducing oxidative phosphorylation/glycolysis interconversion and inhibiting oxidative stress

Myocardial ischemia/reperfusion (I/R) injury is the primary cause of heart damage in the treatment of myocardial infarction, and the imbalance of the energy metabolism in the pathogenesis of myocardial I/R is one of the main triggers of cardiac dysfunction. Monocarboxylate transporter 4 (MCT4) is a key transporter of lactate, which plays a vital role in cellular metabolism. The present study investigated the role and underlying mechanism of MCT4 in myocardial I/R injury. The results of this study showed that MCT4 was upregulated during oxygen-glucose deprivation (OGD) and restored after reoxygenation in cardiomyocytes HL-1. Interestingly, the overexpression of MCT4 increased cell viability and decreased apoptosis of OGD/R-induced HL-1 cells. Furthermore, MCT4 boosted glucose uptake and lactate levels and promoted protein expression of glycolysis regulator LDHA, while also impeding oxidative phosphorylation (OXPHOS) regulators C-MYC and NDUFB8 in OGD/R-induced HL-1 cells. A reduction in reactive oxygen species and oxidative stress markers malonaldehyde and superoxide dismutase was also observed within the OGD/R stimulated HL-1 cells. Additionally, the in vivo exogenous application of MCT4 restored cardiac function, as demonstrated by the reduced infarct size and decreased myocardial apoptosis in I/R rats. OXPHOS and oxidative stress declined, while glycolysis was activated when the I/R mice were injected with AAV-MCT4. Our findings indicate that MCT4 could exert a cardioprotective effect after myocardial I/R injury by inducing OXPHOS/glycolysis interconversion and inhibiting oxidative stress.

Pregnancy-induced physiological hypertrophic preconditioning attenuates pathological myocardial hypertrophy by activation of FoxO3a

Previous studies show a woman's pregnancy is correlated with post-reproductive longevity, and nulliparity is associated with higher risk of incident heart failure, suggesting pregnancy likely exerts a cardioprotection. We previously reported a cardioprotective phenomenon termed myocardial hypertrophic preconditioning, but it is unknown whether pregnancy-induced physiological hypertrophic preconditioning (PHP) can also protect the heart against subsequent pathological hypertrophic stress. We aimed to clarify the phenomenon of PHP and its mechanisms. The pluripara mice whose pregnancy-induced physiological hypertrophy regressed and the nulliparous mice underwent angiotensin II (Ang II) infusion or transverse aortic constriction (TAC). Echocardiography, invasive left ventricular hemodynamic measurement and histological analysis were used to evaluate cardiac remodeling and function. Silencing or overexpression of Foxo3 by adeno-associated virus was used to investigate the role of FoxO3a involved in the antihypertrophic effect. Compared with nulliparous mice, pathological cardiac hypertrophy induced by Ang II infusion, or TAC was significantly attenuated and heart failure induced by TAC was markedly improved in mice with PHP. Activation of FoxO3a was significantly enhanced in the hearts of postpartum mice. FoxO3a inhibited myocardial hypertrophy by suppressing signaling pathway of phosphorylated glycogen synthase kinase-3β (p-GSK3β)/β-catenin/Cyclin D1. Silencing or overexpression of Foxo3 attenuated or enhanced the anti-hypertrophic effect of PHP in mice with pathological stimulation. Our findings demonstrate that PHP confers resistance to subsequent hypertrophic stress and slows progression to heart failure through activation of FoxO3a/GSK3β pathway.

Myocardial ischemia-reperfusion injury; Molecular mechanisms and prevention

Cardiovascular diseases are one of the leading causes of mortality in developed countries. Among cardiovascular disorders, myocardial infarction remains a life-threatening problem predisposing to the development and progression of ischemic heart failure. Ischemia/reperfusion (I/R) injury is a critical cause of myocardial injury. In recent decades, many efforts have been made to find the molecular and cellular mechanisms underlying the development of myocardial I/R injury and post-ischemic remodeling. Some of these mechanisms are mitochondrial dysfunction, metabolic alterations, inflammation, high production of ROS, and autophagy deregulation. Despite continuous efforts, myocardial I/R injury remains a major challenge in medical treatments of thrombolytic therapy, heart disease, primary percutaneous coronary intervention, and coronary arterial bypass grafting. The development of effective therapeutic strategies to reduce or prevent myocardial I/R injury is of great clinical significance.

Anesthesia Management for the Patient with Chronic Decompensated Heart Failure and Low Cardiac Output Undergoing CABG with Advanced Cardiac Monitoring: A Case Report

Introduction

Heart failure (HF) is a complex clinical syndrome caused by a structural or functional heart disorder. One of the most important challenges for anesthesiologists is the management of anesthesia in patients with severe heart failure, which has been facilitated by advanced monitoring systems.

Case Presentation

The patient was a 42-year-old man with a history of hypertension (HTN) and HF with involvement of the three coronary arteries (3VD) with ejection fraction (EF) 15%. He was also a candidate for elective CABG. In addition to the insertion of arterial line in the left radial artery and the Swan-Ganz catheter in the pulmonary artery, the patient was also monitored by the Edwards Lifesciences Vigilance II for cardiac index (CI) and intravenous mixed blood oxygenation (ScvO₂). Hemodynamic changes during and after surgery, as well as during inotrope infusion, were controlled, and the amount of fluid therapy was calculated by gold direct therapy (GDT) method.

Conclusions

Using PA catheter with advanced monitoring and GDT-based fluid therapy guaranteed a safe anesthesia in this patient with severe heart failure and EF < 20%. Moreover, the postoperative complications and duration of ICU stays were significantly reduced.

Icariside II, a Naturally Occurring SIRT3 Agonist, Protects against Myocardial Infarction through the AMPK/PGC-1α/Apoptosis Signaling Pathway

Myocardial infarction (MI) refers to the death of cardiomyocytes triggered by a lack of energy due to myocardial ischemia and hypoxia, and silent mating type information regulation 2 homolog 3 (SIRT3) plays an essential role in protecting against myocardial oxidative stress and apoptosis, which are deemed to be the principal causes of MI. Icariside II (ICS II), one of the main active ingredients of Herbal Epimedii, possesses extensive pharmacological activities. However, whether ICS II can protect against MI is still unknown. Therefore, this study was designed to investigate the effect and possible underlying mechanism of ICS II on MI both in vivo and in vitro. The results showed that pretreatment with ICS II not only dramatically mitigated MI-induced myocardial damage in mice but also alleviated H9c2 cardiomyocyte injury elicited by oxygen and glucose deprivation (OGD), which were achieved by suppressing mitochondrial oxidative stress and apoptosis. Furthermore, ICS II elevated the phosphorylation level of adenosine monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) expression, thereby activating SIRT3. However, these protective effects of ICS II on MI injury were largely abolished in SIRT3-deficient mice, manifesting that ICS II-mediated cardioprotective effects are, at least partly, due to the presence of SIRT3. Most interestingly, ICS II directly bound with SIRT3, as reflected by molecular docking, which indicated that SIRT3 might be a promising therapeutic target for ICS II-elicited cardioprotection in MI. In conclusion, our findings illustrate that ICS II protects against MI-induced oxidative injury and apoptosis by targeting SIRT3 through regulating the AMPK/PGC-1α pathway.

Circ-Ddx60 contributes to the antihypertrophic memory of exercise hypertrophic preconditioning

INTRODUCTION

We previously reported a phenomenon called exercise hypertrophic preconditioning (EHP), the underlying mechanisms of which need further clarification.

OBJECTIVES

We aimed to investigate whether circular RNAs (circRNAs) are involved in EHP.

METHODS

CircRNA sequencing of myocardial tissue was performed in male C57BL/6 mice with EHP and sedentary. Bioinformatics analysis and Sanger sequencing were used to screen hub circRNA expression and to detect full-length circRNAs, respectively. Loss-of-function analyses were conducted to assess the effects of circ-Ddx60 (c-Ddx) on EHP. After 21 days of swimming training or resting, mice underwent transverse aortic constriction (TAC) or sham surgery. Echocardiography, invasive hemodynamic measurement and histological analysis were used to evaluate cardiac remodeling and function. The presence of interaction between c-Ddx and proteins was investigated using comprehensive identification of RNA-binding proteins by mass spectrometry (ChIRP-MS).

RESULTS

In this study, we identified a novel circRNA, named c-Ddx that was preferentially expressed in myocardial tissue and significantly up-regulated in EHP mice. Silencing of c-Ddx attenuated the antihypertrophic effect of EHP and worsened heart failure in mice that underwent TAC. ChIRP-MS and molecular docking analysis validated the combination of c-Ddx and eukaryotic elongation factor 2 (eEF2). Mechanistically, c-Ddx silencing inhibited the increase of phosphorylation of eEF2 and its upstream AMP-activated protein kinase (AMPK) induced by EHP.

CONCLUSIONS

C-Ddx contributes to the antihypertrophic memory of EHP by binding and activating eEF2, which would provide opportunity to search new therapeutic targets for pathological hypertrophy of heart.

Dynamic Involvement of Telocytes in Modulating Multiple Signaling Pathways in Cardiac Cytoarchitecture

Cardiac interstitium is a complex and dynamic environment, vital for normal cardiac structure and function. Telocytes are active cellular players in regulating main events that feature myocardial homeostasis and orchestrating its involvement in heart pathology. Despite the great amount of data suggesting (microscopically, proteomically, genetically, etc.) the implications of telocytes in the different physiological and reparatory/regenerative processes of the heart, understanding their involvement in realizing the heart's mature cytoarchitecture is still at its dawn. Our scrutiny of the recent literature gave clearer insights into the implications of telocytes in the WNT signaling pathway, but also TGFB and PI3K/AKT pathways that, inter alia, conduct cardiomyocytes differentiation, maturation and final integration into heart adult architecture. These data also strengthen evidence for telocytes as promising candidates for cellular therapies in various heart pathologies.

Implications of Oxidative and Nitrosative Post-Translational Modifications in Therapeutic Strategies against Reperfusion Damage

Post-translational modifications based on redox reactions "switch on-off" the biological activity of different downstream targets, modifying a myriad of processes and providing an efficient mechanism for signaling regulation in physiological and pathological conditions. Such modifications depend on the generation of redox components, such as reactive oxygen species and nitric oxide. Therefore, as the oxidative or nitrosative milieu prevailing in the reperfused heart is determinant for protective signaling, in this review we defined the impact of redox-based post-translational modifications resulting from either oxidative/nitrosative signaling or oxidative/nitrosative stress that occurs during reperfusion damage. The role that cardioprotective conditioning strategies have had to establish that such changes occur at different subcellular levels, particularly in mitochondria, is also presented. Another section is devoted to the possible mechanism of signal delivering of modified proteins. Finally, we discuss the possible efficacy of redox-based therapeutic strategies against reperfusion damage.