Myocardial Ischemic Injury Research Articles

Molecular targets for anti-oxidative protection of green tea polyphenols against myocardial ischemic injury

Molecular targets for anti-oxidative protection of green tea polyphenols against myocardial ischemic injury

Abstract 4138339: Abatacept prevents anti-PD-1-induced inflammatory heart failure development after myocardial ischemic injury in mice

Introduction: Immune checkpoint inhibitors (ICI), such as anti-PD-1 monoclonal antibodies are increasingly used in anti-cancer therapy. However, several cardiovascular adverse effects can occur with the use of ICIs, including new-onset heart failure. Hypothesis: We hypothesized that prior myocardial ischemic injury could exacerbate cardiac dysfunction and inflammation caused by anti-PD-1 treatment. Moreover, we investigated whether abatacept, a T-cell co-stimulation blocker, can prevent ICI-induced cardiac effects. Methods: To induce reversible cardiac ischemia, C57Bl/6J mice were treated with isoprenaline (ISOP group) or with PBS (CON group), followed by 16 weeks of recovery period. Following this, mice from both groups were divided into three further treatment groups: isotype control, anti-PD-1, or anti-PD-1 combined with abatacept, and were treated for two weeks, with three weekly intraperitoneal injections. Echocardiography was performed to evaluate cardiac function while myocardial inflammation was assessed by qRT-PCR and immunohistochemistry. Flow cytometry and Western blot were used to investigate changes occurring in the thymus. Results: Mice with normal heart function but with prior ischemic injury and anti-PD-1 treatment (ISOP + anti-PD-1) showed significantly decreased fractional shortening and cardiac index on echocardiography, while in animals with abatacept co-treatment (ISOP+anti-PD-1+abatacept) cardiac function was not altered. Increased immune cell infiltration was seen in the myocardium of the ISOP+anti-PD-1 treated group compared to CON animals, including T-cells and macrophages, with increased expression of pro-inflammatory cytokines, while co-treatment with abatacept ameliorated the inflammatory response. In the thymus, increased expression of PD-1 was found after abatacept co-treatment. Conclusion: Prior myocardial ischemic injury was associated with cardiac dysfunction and inflammation after anti-PD-1 treatment, which was ameliorated by abatacept co-treatment. Patients with prior cardiac ischemic events may be at greater risk for developing ICI-induced cardiotoxicity, including new-onset HF.

M6A-modified circCacna1c regulates necroptosis and ischemic myocardial injury by inhibiting Hnrnpf entry into the nucleus.

Circular RNAs (circRNAs) are differentially expressed in various cardiovascular diseases, including myocardial infarction (MI) injury. However, their functional role in necroptosis-induced loss of cardiomyocytes remains unclear. We identified a cardiac necroptosis-associated circRNA transcribed from the Cacna1c gene (circCacna1c) to investigate the involvement of circRNAs in cardiomyocyte necroptosis. To investigate the role of circCacna1c during oxidative stress, H9c2 cells and neonatal rat cardiomyocytes were treated with hydrogen peroxide (H2O2) to induce reactive oxygen species (ROS)-induced cardiomyocyte death. The N6-methyladenosine (m6A) modification level of circCacna1c was determined by methylated RNA immunoprecipitation quantitative polymerase chain reaction (MeRIP-qPCR) analysis. Additionally, an RNA pull-down assay was performed to identify interacting proteins of circCacna1c in cardiomyocytes, and the regulatory role of circCacna1c in target protein expression was tested using a western blotting assay. Furthermore, theMI mouse model was constructed to analyze the effect of circCacna1c on heart function and cardiomyocyte necroptosis. The expression of circCacna1c was found to be reduced in cardiomyocytes exposed to oxidative stress and in mouse hearts injured by MI. Overexpression of circCacna1c inhibited necroptosis of cardiomyocytes induced by hydrogen peroxide and MI injury, resulting in a significant reduction in myocardial infarction size and improved cardiac function. Mechanistically, circCacna1c directly interacts with heterogeneous nuclear ribonucleoprotein F (Hnrnpf) in the cytoplasm, preventing its nuclear translocation and leading to reduced Hnrnpf levels within the nucleus. This subsequently suppresses Hnrnpf-dependent receptor-interacting protein kinase 1 (RIPK1) expression. Furthermore, fat mass and obesity-associated protein (FTO) mediates demethylation of m6A modification on circCacna1c during necrosis and facilitates degradation of circCacna1c. Our study demonstrates that circCacna1c can improve cardiac function following MI-induced heart injury by inhibiting the Hnrnpf/RIPK1-mediated cardiomyocyte necroptosis. Therefore, the FTO/circCacna1c/Hnrnpf/RIPK1 axis holds great potential as an effective target for attenuating cardiac injury caused by necroptosis in ischemic heart disease.

Resveratrol relieves myocardial ischemia–reperfusion injury through inhibiting AKT nitration modification

ABSTRACT Objective The aim of this study was to clarify whether Protein kinase B (PKB)/AKT is nitrated in myocardial ischemia and reperfusion injury (MIRI) resveratrol (RSV)’s protective effect during this process. Methods We blocked blood flow of the left coronary artery (LAD) of mice and used H9c2 cells under an oxygen-glucose deprivation (OGD) environment as animal and cell models of MIRI. N-methyl-D-aspartic acid receptor (NMDAR) inhibitor MK801, neuronal nitric oxide synthase (nNOS) inhibitor 7-NI and RSV were used as interventions. Nitration of proteins, infarction area, cardiomyocyte apoptosis and AKT nitration sites were detected during this study. Results During in-vivo study, AKT nitration was induced through the NMDAR/nNOS/peroxynitrite (ONOO–) pathway, leading to decreased phosphorylation of AKT and increased cardiomyocyte apoptosis. AKT nitration was decreased and phosphorylation was elevated when administrated with RSV, MK801 and 7-NI. In in-vitro study, AKT nitration and TUNEL positive cells was elevated when administrated with NO donor H9c2 cells after OGD/R, when administrated with RSV, MK801 and 7-NI, AKT nitration and apoptosis was deceased in H9c2 cells. Mass spectrometry revealed that nitration sites of AKT included 14 Tyrosine residues. Discussion RSV could inhibit AKT nitration and elevated phosphorylation through suppressing NMDAR/nNOS/ONOO– pathway and further reduce the apoptosis of cardiomyocytes in of myocardial I/R.

Sestrin2 Attenuates Myocardial Endoplasmic Reticulum Stress and Cardiac Dysfunction During Ischemia/Reperfusion Injury.

Sesn2 (Sestrin2) is a stress-induced protein that provides protective effects during myocardial ischemia and reperfusion (I/R) injury, while endoplasmic reticulum (ER) stress may be a pivotal mediator of I/R injury. The goal of this study was to determine whether Sesn2-mTOR (mammalian target of rapamycin) signaling regulates ER stress during myocardial I/R. In vivo cardiac I/R was induced by ligation and subsequent release of the left anterior descending coronary artery in wild-type (WT) and cardiac-specific Sesn2 knockout(Sesn2cKO) mice. At 6 hours and 24 hours after reperfusion, cardiac function was evaluated, and heart samples were collected for analysis. I/R induced cardiac ER stress and upregulated Sesn2 mRNA and protein levels. Inhibiting ER stress with 4-phenylbutyric acid reduced infarct size by 37.5%, improved cardiac systolic function, and mitigated myocardial cell apoptosis post-I/R. Hearts from Sesn2cKO mice displayed increased susceptibility to ER stress during I/R compared with WT. Notably, cardiac mTOR signaling was further increased in Sesn2cKO hearts compared with WT hearts during I/R. In mice with cardiac Sesn2 deficiency, compared with WT, ER lumen was significantly expanded after tunicamycin-induced ER stress, as assessed by transmission electron microscopy. Additionally, pharmacological inhibition of mTOR signaling with rapamycin improved cardiac function after tunicamycin treatment and significantly attenuated the unfolded protein response and apoptosis in WT and Sesn2cKO mice. Sesn2 attenuates cardiac ER stress post-I/R injury via regulation of mTOR signaling. Thus, modulation of the mTOR pathway by Sesn2 could be a critical factor for maintaining cardiac ER homeostasis control during myocardial I/R injury.

Targeting high-mobility-group-box-1-mediated inflammation: a promising therapeutic approach for myocardial infarction.

Myocardial ischemia, resulting from coronary artery blockage, precipitates cardiac arrhythmias, myocardial structural changes, and heart failure. The pathophysiology of MI is mainly based on inflammation and cell death, which are essential in aggravating myocardial ischemia and reperfusion injury. Emerging research highlights the functionality of high mobility group box-1, a non-histone nucleoprotein functioning as a chromosomal stabilizer and inflammatory mediator. HMGB1's release into the extracellular compartment during ischemia acts as damage-associated molecular pattern, triggering immune reaction by pattern recognition receptors and exacerbating tissue inflammation. Its involvement in signaling pathways like PI3K/Akt, TLR4/NF-κB, and RAGE/HMGB1 underscores its significance in promoting angiogenesis, apoptosis, and reducing inflammation, which is crucial for MI treatment strategies. This review highlights the complex function of HMGB1 in the pathogenesis of myocardial infarction by summarizing novel findings on the protein in ischemic situations. Understanding the mechanisms underlying HMGB1 could widen the way to specific treatments that minimize the severity of MI and enhance patient outcomes.

Kaempferol alleviates myocardial ischemia injury by reducing oxidative stress via the HDAC3-mediated Nrf2 signaling pathway

IntroductionKaempferol (KAE) is a flavonoid found in various plants. Recent studies showed that high dietary intake of KAE was associated with a lower risk of myocardial infarction; however, the cardioprotective mechanism of KAE remains unknown. ObjectivesTo determine the effect of KAE on cardiac injury in isoproterenol (ISO)-induced rats and cobalt chloride (CoCl2)-treated cardiomyocytes, and the underlying mechanisms. MethodsMale rats were pretreated with different doses of KAE for 14 days, and then injected with ISO to induce myocardial ischemia injury. We also established a model of myocardial cell injury using rat H9c2 cardiomyocytes stimulated with CoCl2. ResultsWe found that KAE pretreatment significantly alleviated myocardial injury and improved cardiac function in ISO-injected rats. In addition, KAE reduced oxidative stress in rats with myocardial ischemia by decreasing malondialdehyde concentration and increasing superoxide dismutase activity, and protection of the myocardial mitochondrial structure. KAE also attenuated CoCl2-induced injuryof H9c2 cardiomyocytes via suppression ofoxidative stress. With regard to the mechanism, we found that KAE down-regulated HDAC3 expression and up-regulated Nrf2 expression in ISO-induced rats and CoCl2-stimulated cardiomyocytes. Incubation of cardiomyocytes with HDAC3-selective inhibitor RGFP966 augmented the protective effect of KAE and reduced oxidative stress. By contrast, HDAC3 overexpression by adenovirus attenuated the effect of KAE on oxidative stress compared with KAE treatment group. HDAC3 also regulated Nrf2 expression in the cardiomyocytes with RGFP966 or an adenovirus overexpressing HDAC3; but Nrf2 inhibition reduced the effect of KAE on ROS generation in CoCl2-induced cardiomyocytes. Immunoprecipitation assay showed that HDAC3 interacted with Nrf2 in cardiomyocytes. Further studies found that KAE increased the acetylation level of Nrf2, while HDAC3 overexpression decreased the acetylation of Nrf2 compared with KAE treatment group. ConclusionOur data show that KAE ameliorates cardiac injury by reducing oxidative stress via the HDAC3-mediated Nrf2 signaling pathway in cardiomyocytes.

The effects of acetylated cordycepin derivatives on promoting vascular angiogenesis and attenuating myocardial ischemic injury

BackgroundEnhanced angiogenesis following myocardial infarction (MI) is beneficial to preserve cardiac function. The present study aimed to investigate whether acetylated derivatives of cordycepin altered its original antitumor properties and exerted cardioprotective effects by promoting angiogenesis in vitro and in vivo. MethodsCordycepin and its derivatives with single (DA), double (DAA), and triple acetyl groups (DAAA) were assessed. The cell viability of leukemia U937 cells, malignant hepatoma Huh-7 cells, and human umbilical vascular endothelial cells (HUVECs) treated with cordycepin, DA, DAA, and DAAA were determined. The expression of β-catenin in U937 cells, as well as the expression of p65, p38 and other related signal regulators in HUVECs elicited by lipopolysaccharides (LPS) were also observed. Angiogenesis was determined by tube formation in HUVECs and Matrigel plug assay in mice. Cardiac function following administration of DAAA was evaluated in mice MI model simulated by coronary artery ligation. ResultsThe inhibitory effects of cordycepin and its acetylated derivatives on U937 cells, Huh-7 cells, HUVECs, and the expression of β-catenin in U937 cells were mitigated with increasing acetylation. Intriguingly, DAAA preserved the cell viability of HUVECs compared to other acetylated derivatives. Although DAAA had a significantly diminished antitumor effect compared to cordycepin, it promoted angiogenesis in mice and tube formation in HUVECs and attenuated LPS-induced phosphorylation of p65 and p38. Additionally, administration of DAAA improved cardiac function following coronary artery ligation in mice. ConclusionDAAA could be considered a promising adjunctive therapy to prevent post-MI heart failure through promoting angiogenesis.

ELEVATED TROPONIN OF NON-CORONARY ETIOLOGY A REVIEW

Elevated troponin levels are traditionally associated with acute myocardial infarction (AMI) and are widely used as a specific marker for the diagnosis of ischemic myocardial injury. However, recent studies have shown that elevated troponin levels can occur in several non-coronary conditions, requiring a more careful diagnostic approach to avoid misinterpretations and inadequate management. This study aimed to perform a systematic review of the literature on the non-coronary causes of elevated troponin levels, seeking to identify the main associated clinical conditions and discuss their prognostic value in different contexts. To this end, a systematic review of articles published between 2014 and 2024 was conducted using the PubMed, Scopus and Web of Science databases. The results revealed that conditions such as sepsis, pulmonary embolism (PE), chronic renal failure (CRF), chronic obstructive pulmonary disease (COPD) and tachyarrhythmias are the main non-coronary causes of elevated troponin levels. It is concluded that elevated troponin levels of non-coronary etiology are an important marker of severity and poor prognosis in several systemic conditions. Troponin levels should be interpreted carefully, taking into account the clinical context and underlying conditions of each patient.

MPV17 Prevents Myocardial Ferroptosis and Ischemic Cardiac Injury through Maintaining SLC25A10-Mediated Mitochondrial Glutathione Import.

Ferroptosis is a recently identified iron-dependent programmed cell death with lipid peroxide accumulation and condensation and compaction of mitochondria. A recent study indicated that ferroptosis plays a pivotal role in ischemic cardiac injury with the mechanisms remain largely unknown. This study demonstrates that when an iron overload occurs in the ischemia/reperfusion cardiac tissues, which initiates myocardial ferroptosis, the expression levels of mitochondrial inner membrane protein MPV17 are reduced. Overexpression of MPV17 delivered via adenovirus significantly reduced ferroptosis in both cardiomyocytes with high levels of iron and cardiac I/R tissues. Mitochondrial glutathione (mtGSH), crucial for reactive oxygen species scavenging and mitochondrial homeostasis maintenance, is depleted in myocardial ferroptosis caused by iron overload. This mechanistic study shows that MPV17 can increase mitochondrial glutathione levels through maintaining the protein homeostasis of SLC25A10, which is a mitochondrial inner-membrane glutathione transporter. The absence of MPV17 in iron overload resulted in the ubiquitination-dependent degradation of SLC25A10, leading to impaired mitochondrial glutathione import. Moreover, we found that MPV17 was the targeted gene of Nrf2, which plays a pivotal role in preventing lipid peroxide accumulation and ferroptosis. The decreased expression levels of Nrf2 led to the inactivation of MPV17 in iron overload-induced myocardial ferroptosis. In summary, this study demonstrates the critical role of MPV17 in protecting cardiomyocytes from ferroptosis and elucidates the Nrf2-MPV17-SLC25A10/mitochondrial glutathione signaling pathway in the regulation of myocardial ferroptosis.

Decreased Mrpl42 expression exacerbates myocardial ischemia and reperfusion injury by inhibiting mitochondrial translation

Mammalian mitochondrial DNA (mtDNA) encodes a total of 13 proteins, all of which are subunits of enzyme complexes of the oxidative phosphorylation. The mtDNA-encoded protein synthesis depends on the mitochondrial ribosomal proteins (MRPs), which assemble to form a specialized form of ribosome. Some mtDNA-encoded proteins have been reported to be reduced after myocardial ischemic injury. However, the molecular mechanisms responsible for this decrease and whether this decrease is involved in myocardial ischemia/reperfusion (I/R) injury remains unknown. Here, we found that the mtDNA-encoded protein levels were significantly decreased after I/R injury, while the mRNA levels of these genes were either increased or had no significant change. Subsequently, by querying and analyzing public database resources, we found that the expression of many mitochondrial translation-related proteins tended to decrease after myocardial infarction injury, and the reduction in the expression of these proteins was most obvious for Mrpl42. Furthermore, we found that cardiac Mrpl42 knockdown aggravated I/R-induced cardiac contractile dysfunction and cardiomyocyte death, while restoring Mrpl42 expression in the heart reduced I/R injury. Mrpl42 knockdown impaired the translation of mtDNA-encoded genes, ultimately led to aberrations in mitochondrial morphology and respiratory function. In addition, we found that the decrease in the expression of Mrpl42 after I/R injury was caused by the downregulation of Nrf2, which directly regulates Mrpl42 transcription. Our study revealed that ischemic downregulation of Mrpl42 expression and subsequent inhibition of mitochondrial translation contribute to cardiac I/R injury. Targeting Mrpl42 may be a novel therapeutic intervention for cardiac I/R injury and myocardial infarction.

Cardiomyocyte-derived C-type natriuretic peptide diminishes myocardial ischaemic injury by promoting revascularisation and limiting fibrotic burden

BackgroundC-type natriuretic peptide (CNP) is a significant player in the maintenance of cardiac and vascular homeostasis regulating local blood flow, platelet and leukocyte activation, heart structure and function, angiogenesis and metabolic balance. Since such processes are perturbed in myocardial infarction (MI), we explored the role of cardiomyocyte-derived CNP, and pharmacological administration of the peptide, in offsetting the pathological consequences of MI. MethodsWild type (WT) and cardiomyocyte-restricted CNP null (cmCNP-/-) mice were subjected to left anterior descending coronary artery (LADCA) ligation and acute effects on infarct size and longer-term outcomes of cardiac repair explored. Heart structure and function were assessed by combined echocardiographic and molecular analyses. Pharmacological administration of CNP (0.2 mg/kg/day; s.c.) was utilized to assess therapeutic potential. ResultsCompared to WT littermates, cmCNP-/- mice had a modestly increased infarct size following LADCA ligation but without significant deterioration of cardiac structural and functional indices. However, cmCNP-/- animals exhibited overtly worse heart morphology and contractility 6 weeks following MI, with particularly deleterious reductions in left ventricular ejection fraction, dilatation, fibrosis and revascularization. This phenotype was largely recapitulated in animals with global deletion of natriuretic peptide receptor (NPR)-C (NPR-C-/-). Pharmacological administration of CNP rescued the deleterious pathology in WT and cmCNP-/-, but not NPR-C-/-, animals. Conclusions and implicationsCardiomyocytes synthesize and release CNP as an intrinsic protective mechanism in response to MI that reduces cardiac structural and functional deficits; these salutary actions are primarily NPR-C-dependent. Pharmacological targeting of CNP may represent a new therapeutic option for MI.

Deubiquitinase USP5 regulates RIPK1 driven pyroptosis in response to myocardial ischemic reperfusion injury

BackgroundGasdermin D (GSDMD) mediated pyroptosis plays a significant role in the pathophysiology of myocardial ischemia/reperfusion (I/R) injury. However, the precise mechanisms regulating pyroptosis remain unclear. In the study, we aimed to investigate the underlying mechanism of pyroptosis in myocardial I/R injury.MethodsIn the present study, we analyzed the effects of USP5 on the RIPK1 kinase activity mediated pyroptosis in vitro after H/R (hypoxia/reoxygenation) and in vivo in a MI/R mouse model. TTC and Evan’s blue dye, Thioflavin S and immunohistochemistry staining were performed in wild-type, RIPK1flox/flox Cdh5-Cre and USP5 deficiency mice. CMEC cells were transfected with si-USP5. HEK293T cells were transfected with USP5 and RIPK1 overexpression plasmid or its mutants. The levels of USP5, RIPK1, Caspase-8, FADD and GSDMD were determined by Western blot. Protein interactions were evaluated by immunoprecipitation. The protein colocalization in cells was monitored using a confocal microscope.ResultsIn this study, our data demonstrate that RIPK1 is essential for limiting cardiac endothelial cell (CMEC) pyroptosis mediated by caspase-8 in response to myocardial I/R. Additionally, we investigate the role of ubiquitin-specific protease 5 (USP5) as a deubiquitinase for RIPK1. Mechanistically, USP5 interacts with RIPK1, leading to its deubiquitination and stabilization.ConclusionsThese findings offer new insights into the role of USP5 in regulating RIPK1-induced pyroptosis.

Обратное ремоделирование левого желудочка у пациентов с многососудистым поражением при инфаркте миокарда после реваскуляризации

The role of factors leading to reverse LV remodeling in patients with multivessel ischemic heart disease after percutaneous coronary intervention (PCI) has not been sufficiently studied. The purpose of this article is to provide a brief and concise review of the current understanding of the pathophysiology, clinical predictors, and studies of LV reverse remodeling after complete and incomplete revascularization in patients with multivessel coronary disease. Materials and methods. A systematic review and meta-analysis was conducted in the search systems: eLIBRARY.RU, PubMed, Medline, ResearchGate, Connected papers and Google Scholar mainly from 2019 to 2024 (85.7 %). Results. The cumulative evidence suggests that key factors that can initiate and maintain remodeling processes include myocardial ischemic injury, chronic inflammation, neurohormonal activation, and oxidative stress. A decrease in all these factors can lead to reverse myocardial remodeling. This is possible with complete revascularization during primary PCI, which leads to improved clinical course and reduced 30-day, 1-year and 3-year mortality rates. A combination of biomarkers from different groups may be suitable for predicting reverse remodeling (brain natriuretic peptide precursor-N-terminal natriuretic hormone propeptide, high-sensitivity troponins, C-reactive protein and creatinine kinase), as well as echocardiographic findings, especially 3D-echocardiographic assessments of ventricular volumes, mass and ejection fraction. Conclusion. Complete revascularization is feasible and has great advantages over revascularization of only one infarct-related coronary artery.

Bioinformatics Identification and Validation of Angiogenesis-Related Genes in Myocardial Ischemic Reperfusion Injury.

Angiogenesis plays a critical protective role in myocardial ischemia-reperfusion injury (MIRI); however, therapeutic targeting of associated genes remains constrained. To bridge this gap, we conducted bioinformatics analysis to identify pivotal angiogenesis-related genes in MIRI, potentially applicable for preventive and therapeutic interventions. We collected two mouse heart I/R expression datasets (GSE61592 and GSE83472) from Gene Expression Omnibus, utilizing the Limma package to identify differentially expressed genes (DEGs). Angiogenesis-related genes (ARGs) were extracted from GeneCards, and their overlap with DEGs produced differentially expressed ARGs (ARDEGs). Further analyses included Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and disease ontology to explore biological functions. Weighted gene correlation network analysis (WGCNA) was used to investigate molecular modules linked to MIRI. Additionally, a protein-protein interaction (PPI) network was constructed to pinpoint hub genes relevant to MIRI. Receiver operating characteristic curves were used to assess the diagnostic efficacy of these hub genes for MIRI. An ischemia-reperfusion injury model was established using human cardiac microvascular endothelial cells (HCMECs), with the expression of hub genes validated within this experimental framework. We identified 47 ARDEGs, 41 upregulated and 6 downregulated. PPI network analysis revealed suppressor of cytokine signaling 3 (Socs3), C-X-C motif chemokine ligand 1 (Cxcl1), interleukin 1 beta (Il1b), and matrix metallopeptidase 9 (Mmp9) as hub genes. Receiver operating characteristic (ROC) curve analysis demonstrated strong diagnostic potential for Socs3, Cxcl1, Il1b, and Mmp9. In vitro validation corroborated the mRNA and protein expression predictions. Our study highlights the pivotal role of Socs3, Cxcl1, Il1b, and Mmp9 in MIRI development, their significance in immune cell infiltration, and their diagnostic accuracy. These findings offer valuable insights for MIRI diagnosis and treatment, presenting potential molecular targets for future research.

Comparison of histopathological and triphenyl tetrazolium chloride test in diagnosing myocardial infarction: An autopsy study

Background Sudden and unexpected deaths are increasing drastically. The main cause of sudden death is cardiovascular disease, out of which coronary artery disease predominates forming 80% of the cases. Most of the time, detecting early changes in myocardial infarction during the autopsy is challenging since gross infarct changes do not appear until after 24 to 48 hours of myocardial ischemia injury. So, the aim of this study was to compare two test to detect early changes of Myocardial Infarction one by using Triphenyl Tetrazolium Chloride (TTC) staining of the myocardial tissue, during autopsy and other by histopathological examination. Methods The sample size of 60 hearts taken from all the sudden deaths cases brought to Mortuary with suspected cause of death due to cardiac origin. The heart was obtained from the deceased by standard post-mortem technique. Serial full-thickness transverse sections of the heart were taken at 2 cm intervals from the apex to the atrioventricular groove. All the serial slices of heart are taken for histochemical staining and TTC staining. Results In histopathological examination 34 hearts were diagnosed with myocardial infarction and 26 hearts reported non myocardial infarction. With TTC 40 hearts remained unstained suggestive of myocardial infarction and 20 hearts were stained suggestive of non-infarcted hearts. TTC staining in our study shows an accuracy of 88.33%. Conclusion The result of this study shows that the Triphenyl Tetrazolium Chloride test, a histochemical staining technique of heart, is reliable approach for forensic pathologists to diagnose early myocardial infarction during the post-mortem examination.

Silencing of lncRNA NEAT1 alleviates acute myocardial infarction by suppressing miR-450–5p/ACSL4-mediated ferroptosis

Ferroptosis is principally initiated by dysregulation of iron metabolism and excessive accumulation of ROS, which exacerbates myocardial injury during acute myocardial infarction (AMI). Previous studies have indeed demonstrated the significant involvement of long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (NEAT1) exerts its pleiotropic effects in the pathophysiology of myocardial infarction, heart failure and atherosclerosis by modulating inflammation, apoptosis, and oxidative stress. However, whether and how NEAT1 mediates myocardial ferroptosis remain unknown. In this study, we found that NEAT1 expression was significantly elevated in hypoxic HL-1 cells and AMI mice, while silencing of NEAT1 alleviated lipid peroxidation and myocardial ferroptosis both in vitro and in vivo. Mechanistically, NEAT1 directly sponged miR-450b-5p and negatively regulated its expression. In addition, miR-450b-5p directly targeted Acyl-CoA synthase long-chain family member 4 (ACSL4). Notably, inhibition of miR-450b-5p reversed the role of NEAT1 in AMI mice. Collectively, these findings newly illustrated that NEAT1 acts as a competitive endogenous RNA (ceRNA) of miR-450–5p in AMI. Especially, silencing of NEAT1 effectively ameliorated myocardium ischemia by suppression of ferroptosis via miR-450–5p/ACSL4 pathway, which providing a brand-new therapeutic strategy for myocardial ischemia injury.

Cardioprotective effects of glatiramer acetate after ischemic myocardial injury.

Cardioprotective effects of glatiramer acetate after ischemic myocardial injury.

13-Methylpalmatine improves myocardial infarction injury by inhibiting CHOP-mediated cross-talk between endoplasmic reticulum and mitochondria

Myocardial infarction (MI) is a leading cause of morbidity and mortality worldwide, and endoplasmic reticulum stress (ERS) and mitochondrial Ca2+ overload have been involved in apoptotic cardiomyocyte death during MI. 13-Methylpalmatine (13-Me-PLT) is a natural isoquinoline alkaloid isolated from Coptis chinensis and has not been systematically studied for their potential pharmacological effects in cardiovascular diseases. We conducted the present study to elucidate whether 13-Me-PLT modulates MI pathology in animal MI and cellular hypoxic models, employing state-of-the-art molecular techniques. The results demonstrated that 13-Me-PLT preserved post-ischemic cardiac function and alleviated cardiomyocyte apoptosis. 13-Me-PLT decreased ERS and the communication between ER and mitochondria, which serves as a protective mechanism against mitochondrial Ca2+ overload and structural and functional injuries to mitochondria. Our data revealed mitigating mitochondrial Ca2+ overload and apoptosis by inhibiting CHOP-mediated Ca2+ transfer between inositol 1,4,5-trisphosphate receptor (IP3R) in ER and VDAC1 in mitochondria as an underlying mechanism for 13-Me-PLT action. Furthermore, 13-Me-PLT produced superior effects in alleviating cardiac dysfunction and apoptosis post-MI to diltiazem and palmatine. Collectively, our research suggests that the CHOP/IP3R/VDAC1 signaling pathway mediates ER-mitochondrial Ca2+ transfer and 13-Me-PLT activates this axis to maintain cellular and organellar Ca2+ homeostasis, protecting against ischemic myocardial injury. These findings may offer an opportunity to develop new agents for the therapy of ischemic heart disease.

Myeloid Cells in Myocardial Ischemic Injury: The Role of the Macrophage Migration Inhibitory Factor.

Ischemic heart disease, manifesting as myocardial infarction (MI), remains the leading cause of death in the western world. Both ischemia and reperfusion (I/R) cause myocardial injury and result in cardiac inflammatory responses. This sterile inflammation in the myocardium consists of multiple phases, involving cell death, tissue remodeling, healing, and scar formation, modulated by various cytokines, including the macrophage migration inhibitory factor (MIF). Meanwhile, different immune cells participate in these phases, with myeloid cells acting as first responders. They migrate to the injured myocardium and regulate the initial phase of inflammation. The MIF modulates the acute inflammatory response by affecting the metabolic profile and activity of myeloid cells. This review summarizes the role of the MIF in regulating myeloid cell subsets in MI and I/R injury and discusses emerging evidence of metabolism-directed cellular inflammatory responses. Based on the multifaceted role of the MIF affecting myeloid cells in MI or I/R, the MIF can be a therapeutic target to achieve metabolic balance under pathology and alleviate inflammation in the heart.