Myocardial Infarction Model Research Articles

Cardiac rehabilitation attendance and outcomes 3 years after acute coronary syndrome (ACS): Linked national data of the SNAPSHOT ACS audit

Abstract Background In international guidelines, cardiac rehabilitation is recommended to reduce readmissions, mortality and improve disease management. However, evidence from a long-term follow-up in a representative cohort is scarce. Purpose To compare 3-year outcomes among acute coronary syndrome (ACS) survivors who attended cardiac rehabilitation programs and those who did not. Methods This was a follow-up of the SNAPSHOT ACS cohort in 1,920 Australians. Clinical data of those presenting with suspected ACS, hospitalised, discharged alive and followed for 18 months were linked to jurisdictional/national regulatory hospitalisation, mortality and pharmacotherapy records. Outcomes were all-cause and cardiovascular mortality, myocardial infarction (MI) and cardiovascular readmissions. Cox regression was used to analyse all-cause mortality, and Fine and Gray competing risk model for cardiovascular mortality, MI and cardiovascular readmissions, where non-cardiovascular mortality or all-cause mortality were competing events. The models were adjusted for age, sex, discharge diagnosis and coronary revascularisation. Results The cohort was aged 66±13.5 years; 60% were male, 31% had a discharge diagnosis of MI, and 490 (26%) attended cardiac rehabilitation. Cardiac rehabilitation attendees more frequently received coronary revascularisation and had a discharge diagnosis of MI during index admission. Attendees were more likely to be men (70% vs 57%, p<0.001) with a family history of coronary disease (43% vs 36%, p=0.008). The prescription of ≥3 guideline-indicated medications was higher in cardiac rehabilitation attendees. Compared to those who did not attend cardiac rehabilitation, the hazard of all-cause mortality was lower for the attendees (4.3% vs 8.6%, HR: 0.55, 95% CI: 0.34-0.91), but the hazard of MI and cardiovascular readmissions significantly greater in the attendees (17% vs 8.5%, HR: 1.99, 95% CI: 1.41-2.82; 42% vs 33%, HR: 1.34, 95% CI: 1.10-1.63; respectively) (Figure). There was insufficient cardiovascular mortality between groups to fit a statistical model (n=7 (1.4%) vs n=24 (1.7%), p=0.705). Conclusions Survivors of ACS attending cardiac rehabilitation were associated with reduced all-cause mortality and increased readmissions related to MI and cardiovascular disease at 3 years follow-up. These findings support secondary prevention strategies to mitigate mortality risk after ACS.

CD14 blockade preserves left ventricular structure and systolic function in a murine model of ST-elevation myocardial infarction

Abstract Background Cluster of differentiation-14 (CD14) facilitates the excessive pro-inflammatory monocyte-macrophage response to myocardial injury. Both acute and chronic infiltration of pro-inflammatory macrophages are implicated in the immunological progression of ischemic heart failure. However, investigation of clinically practicable strategies of CD14 blockade are yet to be reported. Purpose This fully blinded and randomised preclinical study evaluated the efficacy of a neutralising anti-CD14 antibody given at reperfusion in a murine model of reperfused ST-elevation myocardial infarction (STEMI) with key clinical features. Methods Large anterior STEMI was induced in 48 adult mice by left anterior descending coronary artery occlusion for 1 h prior to reperfusion and randomisation to receive anti-CD14 antibody, isotype control (IgG2a) or saline weekly for four weeks (independently blinded). Outcome measures included functional assessments by 9.4T cardiac magnetic resonance (CMR) imaging and ultra-high-resolution echocardiography at 21- and 28-days post-STEMI, respectively. Results Multi-plane short axis CMR at 21-days post-STEMI revealed greater left ventricular (LV) ejection fraction in the anti-CD14 antibody-treated group compared with saline- and isotype-treated controls (30±1 vs 19±1 and 20±1 %, respectively, p<0.001; Figure 1A). CMR also revealed reduced LV dilatation with anti-CD14-treatment compared to control groups (76±5 vs 102±8 and 107±7 µl EDV in saline- and isotype-treated controls, respectively, p<0.05). Parasternal long axis echocardiography at 28 days post-STEMI confirmed that anti-CD14 antibody treatment was associated with greater LV systolic function compared to saline and isotype controls (30±1 vs 24±1 and 25±2 % EF, respectively, p<0.05; Figure 1B). Preservation of LV end-diastolic (86±4 vs 111±6 and 101±5 µl, p<0.01) and end-systolic (61±3 vs 84±5 and 77±5 µl, p<0.01) volumes was also observed with anti-CD14 treatment. Global longitudinal strain (GLS) of the LV was also significantly greater at 28 days post-STEMI with anti-CD14 treatment relative to saline and isotype controls (-8.5±0.4 vs -6.8±0.3 and -6.6±0.4 %, respectively, p<0.05). Conclusion(s) The findings of this fully blinded and randomised preclinical study provide evidence of a clinically practicable strategy of CD14 blockade initiated at reperfusion to mitigate progressive LV systolic dysfunction and dilatation post-STEMI.Figure 1.Functional outcome measures

Direct comparison of mechanical circulatory support devices in porcine model of acute myocardial infarction complicated by ventricular septal defect and cardiogenic shock

Abstract Introduction Despite urgent clinical need, until now optimal strategy for mechanical circulatory support in acute myocardial infarction (AMI) complicated by ventricular septal defect (VSD) and cardiogenic shock has not been determined. Purpose The aim of our study was to compare hemodynamic effects of intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO) and Impella CP in the animal model of AMI complicated by VSD and cardiogenic shock. Methods Under general anesthesia and mechanical ventilation in pigs (sus scrofa domestica), using partial sternotomy, AMI was induced by ligation of left anterior descending. VSD was simulated by insertion of 25F cannulas into the left and right ventricles and their extracorporeal connection by 3/8 tubes generating left-to-right shunt. The hemodynamic effect of ECMO (2 L/min), IABP, and Impella CP (2 L/min) was evaluated by the measurement of the left ventricular end-diastolic pressure (LVEDP), mean arterial pressure (MAP), carotid flow (CAR) as a surrogate of total circulatory output, and VSD flow. Data are presented as mean (SD), P < 0.05 was considered statistically significant. Results Eleven animals were used, one died after induction of AMI, ten pigs completed all study procedures. Baseline (no mechanical support) LVEDP was 13.8 (3.0) mmHg, MAP 54.5 (11.0) mmHg, CAR 290.9 (37.3) mL/min, and VSD 1174.0 (499.3) mL/min (Table 1). IABP significantly improved all parameters in comparison to Baseline (Table 1). ECMO significantly improved MAP and CAR not only in comparison to Baseline but also in comparison to IABP and Impella; on the other hand, ECMO increased VSD flow (Table 1). Impella significantly improved all parameters with the largest effect on LVEDP and VSD flow (Table 1). Conclusions All tested devices improved the key hemodynamic parameters of MAP and CAR, however each to different extent. Individual devices influenced differently LVEDP and VSD flow. The results of this study may help in selection of optimal therapeutic strategy in AMI complicated by VSD and cardiogenic shock.Table 1.Hemodynamic outcomes.

Single cell multi-omics analysis unveils a distinct mechanism of exercise-mediated cardioprotection in ischemic cardiomyopathy

Abstract Background Exercise is pivotal in heart disease prevention, with proven cardioprotective effects in clinical trials. However, its precise molecular mechanisms remain elusive. Recent advancements in single-cell omics have revealed cellular heterogeneity within heart tissues, offering a deeper understanding of the pathophysiology of cardiac diseases. Purpose To investigate the exercise-induced physiological changes in heart tissue at the single-cell level and elucidate the molecular mechanisms underlying its cardioprotective effect on ischemic cardiomyopathy. Methods Murine myocardial infarction (MI) model was established by ligating the left ascending coronary artery, and a six-week voluntary wheel running exercise regimen was implemented to investigate the effect of aerobic exercise on ischemic cardiomyopathy. Integrated multi-omics analyses of single-cell DNA methylation profiling, single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq) and single-nucleus RNA sequencing (snRNA-seq) were conducted to clarify the molecular mechanism of exercise-mediated cardioprotection at single-cell resolution. Overexpression and short hairpin RNA-mediated knockdown of gene X were conducted for murine MI model using cardiomyocyte-specific Myo-AAV2a vector. snRNA-seq of heart tissues from heart failure patients was performed to validate the clinical significance of the expression of gene X in cardiomyocytes. Results Exercise attenuates pathological cardiac remodeling, inducing physiological hypertrophy in non-infarcted areas while suppressing pathological remodeling of cardiomyocytes in infarct border zones. Single-cell epigenetic analysis unveiled intricate molecular mechanisms underlying exercise-induced transcriptome changes, providing insights into the gene regulatory networks modulated by exercise in the heart. In addition, integrated with snRNA-seq, we identified exercise-specific cardiomyocyte clusters, highlighting the substantial role of gene X in the molecular mechanism of exercise. Functional studies confirmed the essential role of gene X in exercise-induced cardioprotection, as its overexpression suppressed the adverse remodeling after MI and knockdown abolished the beneficial effects of exercise. Furthermore, snRNA-seq of heart failure patients revealed that higher expression of gene X was associated with ventricular reverse remodeling and favorable clinical outcomes, underscoring its significance in the pathophysiology of patients with heart failure. Conclusion Our study elucidates exercise-specific gene expression regulation networks in ischemic cardiomyopathy by unraveling the cellular heterogeneity and molecular changes associated with exercise. We identified gene X as a central player in exercise-mediated cardioprotection and further confirmed its significance in clinical settings, providing a potential therapeutic target for heart failure.

A newly developed small-molecule ErbB4 agonist reduces reactive cardiac fibrosis and adverse ventricular remodelling after myocardial infarction in a sex-specific manner

Abstract Background The beneficial effects of the neuregulin/ErbB pathway on the diseased heart have been well-established. The anti-fibrotic and cardioprotective aspects of neuregulin are largely attributable to the activation of the ErbB4 receptor. We recently developed a small-molecule selective ErbB4 agonist, which reduced collagen production in cultured fibroblasts and prevented oxidative-stress induced cardiomyocyte death in vitro. Purpose In order to evaluate the in vivo effects of this small-molecule ErbB4 agonist (referred to as compound, Cpd), we assessed its effect on left ventricular remodelling, cardiac fibrosis and cardiac function in a murine model of myocardial infarction (MI). Since there is a potential interaction between ErbB4 and the oestrogen receptor, we also aimed to evaluate whether these effects were sex-dependent. We hypothesised that Cpd would attenuate left ventricular remodelling, reduce cardiac fibrosis and help retain cardiac function in a sex-specific manner. Methods Mice were divided by sex and then further divided into three experimental groups: a sham group, an MI group receiving Cpd (MI/Cpd), and a control MI group receiving vehicle only (MI/Veh). MI was induced by ligating the left descending coronary artery. Seven days after MI, mice started treatment with either Cpd (2mg/kg/d) or its vehicle through subcutaneous osmotic minipumps. Cardiac ultrasound was performed weekly until mice were sacrificed after four weeks of treatment. Hearts were excised and stained with Masson’s trichrome to assess reactive cardiac fibrosis in the myocardium of the left ventricle, located remote from the infarction scar. A WGA-isolectinB4-DAPI immunofluorescent stain was performed to assess cardiomyocyte cross-sectional area in order to evaluate cardiomyocyte hypertrophy. Results In females (n=25), Cpd significantly decreased left ventricular end-diastolic volume compared to vehicle (LVEDV, Fig.1A, 80±23 µl vs.108±29 µl, p=0.045) and induced a slightly increased left ventricular ejection fraction (LVEF, Fig.1B, 32±12% vs. 22±9%, p=0.086). In addition, Cpd significantly reduced reactive interstitial fibrosis myocardium (Fig.1C, fibrotic area, 1.4±1.0% vs. vehicle: 3.8±3.1%, p=0.0363). In males (n=30), Cpd had no significant effects on either of the parameters mentioned above, (Fig.1E-G). There was no significant treatment effect in either group on cardiomyocyte cross sectional area (Fig.1D, Fig.1H). Conclusion Treatment with the novel small-molecule ErbB4 agonist attenuates left ventricular dilation and reactive interstitial fibrosis after MI in female mice, but not in males. These data support the premise that small molecule-induced ErbB4 activation is a potential new therapy for heart failure, especially in female patients. The mechanisms underlying the sex-dependent effects warrant further exploration.Figure 1

CSWT improves ventricular function by promoting angiogenesis through Rho/ROCK/ERK1/2 signal pathway in infarcted myocardium in rats

Abstract Objective This study aimed to investigate the effects of extracorporeal cardiac shock wave therapy (CSWT) on myocardial ischemia and cardiac function in rats with myocardial infarction, and to explore its impact on the expression of myocardial vascular endothelial growth factor and the extent of myocardial fibrosis, thereby elucidating the mechanism of angiogenesis. Methods A rat model of myocardial infarction was induced by ligating the left anterior descending branch of the coronary artery, confirmed by echocardiography. Animals were randomly assigned to five groups: sham operation group, myocardial infarction group, myocardial infarction + CSWT group, myocardial infarction + Y-27632 group, and myocardial infarction + CSWT + Y-27632 group. Cardiac function was evaluated by echocardiography on the 16th and 72nd day post-surgery. Myocardial morphology was assessed by HE staining, and the extent of myocardial fibrosis was determined by Masson's trichrome staining. Immunohistochemical staining for factor VIII was conducted to observe angiogenesis in each infarcted area. Western blotting was employed to detect the protein expression of extracellular regulated kinase (ERK1/2) and pro-angiogenic cytokines in the infarct border zone. Results CSWT treatment significantly reduced myocardial fibrosis and improved cardiac function compared to the myocardial infarction group. Additionally, CSWT upregulated ERK expression and angiogenesis-related factors, promoting angiogenesis. The beneficial effects of CSWT were abolished by inhibiting the Rho/ROCK/ERK1/2 pathway. Furthermore, the area of myocardial fibrosis was significantly reduced in the MI+Y-27632 group compared to the myocardial infarction group (p < 0.01), and left ventricular systolic function index was significantly higher in the myocardial infarction group. Conclusions CSWT may promote angiogenesis post-myocardial infarction by activating the Rho/ROCK/ERK1/2 pathway. Additionally, Y-27632 may improve cardiac function in rats with myocardial infarction, potentially through mitigating myocardial fibrosis.echo images of ratsprotein expression by WB

Oxct1 regulates cardiomyocyte PANoptosis in acute myocardial infarction via succinylating Tfam

Abstract Background Myocardial ischemia leads to various forms of programmed cell death in cardiomyocytes, resulting in acute myocardial infarction (AMI) and the development of heart failure in the long term. PANoptosis is a unique cell death regulatory mechanism orchestrated by the PANoptosome complex, which regulates and intersects multiple forms of programmed cell death. Oxct1 has been demonstrated to play crucial roles in tumors, pressure-overloaded hearts, and cardiac endothelial cells. However, whether Oxct1 is involved in the regulation of PANoptosis and correlated mechanisms during AMI remains unclear. Purpose To elucidate the role of Oxct1 in cardiomyocytes during AMI and uncover the potential mechanisms. Methods The myocardial infarction model induced by anterior descending branch ligation and the primary cardiomyocytes hypoxia model were employed in our experiments. Small interfering RNA (siRNA) and adenovirus were constructed to knock down and overexpress Oxct1 for altering its expression in cardiomyocytes in vitro. Cardiomyocyte-specific knockout mice were constructed to alter Oxct1 expression in vivo. PANoptosis characteristic measurement, including Z-DNA binding protein 1(Zbp1), pyroptosis markers, apoptosis markers, necroptosis markers, ROS, and mitochondrial morphology, were performed to verify the ability of Oxct1 to regulate the PANoptosis of cardiomyocytes. Cardiac morphological, structural, and functional changes were measured to assess the effect of Oxct1 on AMI. RNA sequencing was performed to identify downstream pathways. Immunoprecipitation +Mass spectrometry and co-immunoprecipitation were performed to identify the specific binding factors of Oxct1. Results We found that the expression of Oxct1 was significantly elevated after AMI. Besides, gain- and loss-of-function experiments were constructed both in vitro and in vivo. Functionally, Oxct1 knockdown significantly enhanced cardiomyocyte vitality, reduced ROS production and mtDNA cytoplasmic release in hypoxic cardiomyocytes. In vivo, Oxct1cko mice manifested reduced infarct size, improved cardiac function and alleviated cardiac fibrosis by mitigating PANoptosis. However, Oxct1 overexpression resulted in the opposite effects. Afterwards, RNA-seq analysis results showed that cytosolic DNA-sensing pathway was significantly enriched in Oxct1 knockdown cardiomyocytes. Mechanistically, Oxct1 could bind to mitochondrial transcription factor A(Tfam) and increased its succinylation, promoting Tfam degradation. Downregulation of Tfam resulted in ROS production and mtDNA damage, while mtDNA released into cytoplasm could activate Zbp1 and induce cascade reaction of PANoptosis. Conclusion This study demonstrates that Oxct1 promotes Tfam degradation through succinylation, exacerbating ROS production, mtDNA damage and cytoplasmic release, ultimately leading to cardiomyocyte PANoptosis in AMI.

Inhibiting chondroitin sulfate synthase 1 ameliorates hyperplastic arterial remodelling

Abstract Introduction Hyperplastic arterial remodelling is characterized by intima-media thickening, lumen narrowing, inflammation and increased extracellular matrix (ECM) deposition. Chondroitin sulfate (CS) glycosaminoglycans, the unbranched polysaccharide chains of proteoglycans, are important components of ECM. We previously found CS accumulated in adversely remodelled heart and artery, aggravating cardiac deterioration. Objective We aim to explore a therapeutic strategy to interfere with CS synthesis and investigate its potential in ameliorating hyperplastic arterial remodelling. Methods Through single-cell RNA sequencing of non-cardiomyocytes cardiac cells from mouse myocardial infarction model, chondroitin sulfate synthase 1 (CHSY1) was identified as the primary CS synthase and was increased during disease progression. A Chsy1 knockout (KO) mouse strain was generated. Fibrosis and arterial remodelling were induced using: (i) 4 weeks of angiotensin II/phenylephrine (AngII/PE) infusion through subcutaneous osmotic minipumps; and (ii) transverse aortic constriction surgery. To assess the therapeutic potential of CHSY1 inhibition in ameliorating hyperplastic arterial remodelling, Chsy1 was knockdown by dsiRNA post disease onset. Mechanism of action was investigated using primary vascular smooth muscle cells (VSMCs). Results Chsy1 KO reduced CS and its stereoisomer dermatan sulfate in the heart to 42 ± 22% and 36 ± 7% respectively, whereas other types of glycosaminoglycans remain intact. KO mice were protected against phenotypes of hyperplastic arterial remodelling induced by the two disease models in both the coronary and carotid arteries. For example, 90.1% of coronary arterial fibrosis and 79.7% of macrophage infiltration induced by AngII/PE was declined in KO mice compared to WT mice, while cardiac function as stroke volume was augmented by 41.3%. Concomitantly, carotid arterial wall thickening was lower by 36.5% and distensibility was higher by 36.7%, validating Chsy1 as a potent target. As a therapeutic approach, weekly intravenous injection of dsiRNA achieved Chsy1 reduced to 30.2 ± 5.5% in the carotid artery and 72.5 ± 4.7% in the heart. Post disease onset, Chsy1 KD therapy reduced fibrosis by 59.9% in the coronary artery (P = 0.006) and improved stroke volume by 25.6% (P = 0.036). The structural integrity and function of carotid arteries were well-reserved, manifesting as improved distensibility (29%, P = 0.016), increased elastin/perimeter ratio (15%, P = 0.002), and reduced macrophage infiltration (38%, P = 0.029). In vitro, CHSY1 inhibition suppressed migration and cytokine production of macrophages, fibroblast-to-myofibroblast transition, and VSMC hyperproliferation. NOTCH3 signalling was found to be positively correlated with CHSY1 modulation. Conclusions We demonstrated that inhibiting CHSY1 is necessary and sufficient to block CS synthesis. Chsy1 KD by dsiRNA is an effective therapy to ameliorate hyperplastic arterial remodelling.

The alternative splicing landscape of infarcted mouse heart identifies isoform level therapeutic targets

Alternative splicing is an important process that contributes to highly diverse transcripts and protein products, which can affect the development of disease in various organisms. Cardiovascular disease (CVD) represents one of the greatest global threats to humans, particularly acute myocardial infarction (MI) and subsequent ischemic reperfusion (IR) injury, which involve complex transcriptomic changes in heart tissues associated with metabolic reshaping and immunological response. In this study, we used a newly developed ONT full-length transcriptomic approach and performed transcript-resolved differential expression profiling in murine models of MI and IR. We built an analytical pipeline to reliably identify and quantify alternative splicing products (isoforms), expanding on the currently available catalog of isoforms described in mice. The updated alternative splicing landscape included transcripts, genes, and pathways that were differentially regulated during IR and MI. Our study establishes a pipeline to profile highly diverse isoforms using state-of-the-art long-read sequencing, builds a landscape of alternative splicing in the mouse heart during MI and IR.

Separating Risk Prediction: Myocardial Infarction vs. Ischemic Stroke in 6.2M Screenings.

Traditional cardiovascular disease risk prediction models generate a combined risk assessment for myocardial infarction (MI) and ischemic stroke (IS), which may inadequately reflect the distinct etiologies and disparate risk factors of MI and IS. We aim to develop prediction models that separately estimate the risks of MI and IS. Our analysis included 6,242,404 individuals over 40 years old who participated in a cardiovascular health screening examination in 2009. Potential predictors were selected based on a literature review and the available data. Cox proportional hazards models were used to construct 5-year risk prediction models for MI, and IS. Model performance was assessed through discrimination and calibration. During a follow-up of 39,322,434.39 person-years, 89,140 individuals were diagnosed with MI and 116,259 with IS. Both models included age, sex, body mass index, smoking, alcohol consumption, physical activity, diabetes, hypertension, dyslipidemia, chronic kidney disease, and family history. Statin use was factored into the classification of dyslipidemia. The c-indices for the prediction models were 0.709 (0.707-0.712) for MI, and 0.770 (0.768-0.772) for IS. Age and hypertension exhibited a more pronounced effect on IS risk prediction than MI, whereas smoking, body mass index, dyslipidemia, and chronic kidney disease showed the opposite effect. The models calibrated well for low-risk individuals. Our findings underscore the necessity of tailored risk assessments for MI and IS to facilitate the early detection and accurate identification of heterogeneous at-risk populations for atherosclerotic cardiovascular disease.

Preventive impact of probiotic supplements on heart injury and inflammatory indices in a rat model of myocardial infarction: histopathological and gene expression evaluation.

Although there is a bulk of evidence on the favorable effect of probiotics on the cardiac system, their role in the management of myocardial infarction is not clear. Three viable probiotic bacterial strains, namely Lactobacillus reuteri, Bifidobacterium longum, and Bifidobacterium lactis, were gavaged to the rats daily for 28 days prior to the induction of myocardial injury. Myocardial injury was induced by the use of isoproterenol (ISO) in the probiotics, control and sham groups. The heart tissues were catheterized to evaluate the histopathological parameters and measure the expression of genes related to inflammation. Treatment with ISO caused subendocardial necrosis and rupture of cardiac myofibrils. Pretreatment with probiotics reduced the size of myocardial infarction caused by ISO. Also, in the probiotic group, a relative decrease in the amount of tissue fibrosis and rupture of cardiomyocytes fibers was seen. Pretreatment with probiotics partially ameliorated myocardial necrosis, edema and leukocyte infiltration. Also, a remarkable decrease was detected in the expression of tissue proinflammatory genes in the pretreated group with probiotics. Thus, viable probiotic supplementation may ameliorate or prevent cardiac injury. Additional preclinical and clinical studies are required to clarify the impact of probiotics in the prevention and management of cardiovascular disease.

Myocardial infarction in rats was alleviated by MSCs derived from the maternal segment of the human umbilical cord.

Mesenchymal stem cells (MSCs) are safe and effective in treating myocardial infarction (MI) and have broad application prospects. However, the heterogeneity of MSCs may affect their therapeutic effect on the disease. We recently found that MSCs derived from different segments of the same umbilical cord (UC) showed significant difference in the expression of genes that are related to heart development and injury repair. We therefore hypothesized that those MSCs with high expression of above genes are more effective to treat MI and tested it in this study. MSCs were isolated from 3cm-long segments of the maternal, middle and fetal segments of the UC (maternal-MSCs, middle-MSCs and fetal-MSCs, respectively). RNA-seq was used to analyze and compare the transcriptomes. We verified the effects of MSCs on oxygen-glucose deprivation (OGD)-induced cardiomyocyte apoptosis in vitro. In vivo, a rat MI model was established by ligating the left anterior descending coronary artery, and MSCs were injected into the myocardium surrounding the MI site. The therapeutic effects of MSCs derived from different segments of the UC were evaluated by examining cardiac function, histopathology, cardiomyocyte apoptosis, and angiogenesis. Compared to fetal-MSCs and middle-MSCs, maternal-MSCs exhibited significantly higher expression of genes that are associated with heart development, such as GATA-binding protein 4 (GATA4), and myocardin (MYOCD). Coculture with maternal-MSCs reduced OGD-induced cardiomyocyte apoptosis. In rats with MI, maternal-MSCs significantly restored cardiac contractile function and reduced the infarct size. Mechanistic experiments revealed that maternal-MSCs exerted cardioprotective effects by decreasing cardiomyocyte apoptosis, and promoting angiogenesis. Our data demonstrated that maternal segment-derived MSCs were a superior cell source for regenerative repair after MI. Segmental localization of the entire UC when isolating hUCMSCs was necessary to improve the effectiveness of clinical applications.

Sirt1/Nrf2/TNFα; TLR4/Myd88/NF-κB signaling pathways are involved in mediating hepatoprotective effect of bupropion in rat model of myocardial infarction

Background The aim of the current study is to identify the possible protective effect of bupropion (BUP) on liver injury in rat model of myocardial infarction (MI). BUP was administered in the presence and absence of MI. Materials and methods Thirty-two Wistar adult male rats were randomly arranged into four groups: control, BUP (30 mg/kg/day, intraperitoneal) for 28 days, isoproterenol (ISO) was injected subcutaneous (85 mg/kg) in the 26th and 27th days and BUP/ISO groups. Cardiac and hepatic enzymes were measured, also Hepatic oxidative stress indicators, as well as inflammatory and apoptotic biomarkers, were evaluated. Cardiac and hepatic histopathological examination and hepatic nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) immunohistochemical study were also detected. Results ISO significantly increased cardiac and hepatic enzymes, hepatic oxidative stress, inflammatory, apoptotic, with a histopathological picture of cardiac and hepatic damage and high hepatic NF-κB immunoexpression were detected. BUP significantly normalized the upraised oxidative, inflammatory, and apoptotic parameters, with an impressive improvement in the histopathological picture and a reduction in hepatic NF-κB immunoexpression. Conclusion BUP protects against liver injury on top of MI in rat model via modulation of Sirtuin type 1 (Sirt1)/Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/tumor necrosis factor α (TNFα); Toll-like receptor 4 (TLR4)/Hepatic myeloid differentiation primary response 88(Myd88)/NF-κB signaling pathways.

Mechanical stimulation promotes the maturation of cardiomyocyte-like cells from P19 cells and the function in a mouse model of myocardial infarction.

In this study, we aimed to promote the maturation of cardiomyocytes-like cells by mechanical stimulation, and evaluate their therapeutic potential against myocardial infarction. The cyclic tensile strain was used to induce the maturation of cardsiomyocyte-like cells from P19 cells in vitro. Western blot and qPCR assays were performed to examine protein and gene expression, respectively. High-resolution respirometry was used to assay cell function. The induced cells were then evaluated for their therapeutic effect. In vitro, we observed cyclic tensile strain induced P19 cell differentiation into cardiomyocyte-like cells, as indicated by the increased expression of cardiomyocyte maturation-related genes such as Myh6, Myl2, and Gja1. Furthermore, cyclic tensile strain increased the antioxidant capacity of cardiomyocytes by upregulating the expression Sirt1, a gene important for P19 maturation into cardiomyocyte-like cells. High-resolution respirometry analysis of P19 cells following cyclic tensile strain showed enhanced metabolic function. In vivo, stimulated P19 cells enhanced cardiac function in a mouse model of myocardial infarction, and these mice showed decreased infarction-related biomarkers. The current study demonstrates a simple yet effective mean to induce the maturation of P19 cells into cardiomyocyte-like cells, with a promising therapeutic potential for the treatment of myocardial infarction.

Cardioprotective effect of lithium ascorbate in an in vivo model of myocardial infarction

The aim of the work was to study the cardioprotective effect of lithium ascorbate in an in vivo model of myocardial infarction. In the course of the study, we searched for compounds promising for therapy of acute myocardial infarction.Materials and methods. Myocardial infarction was modeled in Wistar rats by ligating the left coronary artery (the duration of ischemia was 45 minutes) followed by ligature loosening and 120-minute reperfusion. All manipulations were performed under alpha-chloralose anesthesia with mechanical lung ventilation and recording heart rate, blood pressure, and ECG. Lithium ascorbate was administered intravenously at a dose of 100 mg / ml before ischemia. The area at risk (the ischemia / reperfusion zone) was detected by staining the myocardium with tightened ligature with 5% potassium permanganate. After that consecutive myocardial slices were prepared, and infarct size was determined. Differentiation of the infarct size from the area at risk was performed by staining with 1% 2,3,5-triphenyl tetrazolium chloride solution for 30 minutes at 37 ºC. The infarct size and the area at risk were determined by the planimetric method. The serum concentration of myocardial damage marker creatine kinase-MB (CK-MB) was measured using ELISA kits.Results. Lithium ascorbate reduced the infarct size / area at risk ratio by 38% and decreased the serum CPKMB level in the experimental animals by 42% compared to the control group. Lithium ascorbate did not affect hemodynamics parameters during coronary artery occlusion and reperfusion.Conclusion. The cardioprotective effect of lithium ascorbate in cardiac ischemia / reperfusion in vivo was found.

Quantification of extra-cardiac damage following acute myocardial infarction using cis- and trans-4-[18F]fluoro-L-proline PET imaging

The preclinical surgically-induced models of myocardial infarction (MI) have been extensively utilised for studying the wound healing response in the mammalian heart. It is well-established that these invasive procedures induce marked acute systemic inflammation and adverse haemodynamic derangements, which can result in extra-cardiac tissue injury and remodelling; however, the extent of this has not yet been robustly characterised. Here, using a rat permanent coronary artery ligation (PL) model of MI and the cis- and trans-4-[18F]fluoro-l-proline positron emission tomography (PET) probes, targeting active misfolded and triple-helical collagen biosynthesis, respectively, we conducted an exploratory time-course analysis of the associated extra-cardiac tissue remodelling post-injury. Our results showed an increased cis-4-[18F]fluoro-l-proline PET signal in the liver (P = 0.02; two sample t-test) and lung (P = 0.03; two sample t-test) at the acute day 7 timepoint in the MI group compared to the Sham group (n = 3-6), which was not apparent at the later timepoints (days 14, 28, and 84). Ex vivo quantification of the deposited collagen in extra-cardiac tissues using Sirius red histochemical staining and the total hydroxyproline assay validated the apparent time course trends observed with [18F]fluoro-l-proline PET. These findings suggest that the liver and lungs are susceptible to acute injury in the rat PL model of MI and align with numerous clinical reports of extracardiac injury in MI patients. Moreover, our results highlight the suitability of [18F]fluoro-l-proline PET as a systems-based imaging technique for investigating active collagen biosynthesis across multiple organs.

Metformin's cardioprotective role in isoprenaline-induced myocardial infarction: Unveiling insights into the AMPK, NF-κB, JAK2/STAT3 pathways, and cholinergic regulation

AimDespite advancements in treatment modalities, myocardial infarction (MI) remains a significant global cause of mortality and morbidity. Metformin (MET), a commonly used antidiabetic medication, has demonstrated potential in various cardioprotective mechanisms. This study investigated whether MET could alleviate the histopathological, electrocardiographic, and molecular consequences of MI in rats. Materials and methodsThe study hypothesis was tested using an isoprenaline (ISOP)-induced MI model, where male Wistar rats were injected with ISOP (85 mg/kg/day, s.c., for 2 days) and treated with MET at the doses of 500 and 1000 mg/kg/day for 18 days or left untreated. Key findingsISOP-treated rats exhibited several indicators of MI, including significant ST-segment depression and prolonged QT-intervals on ECGs, worsened left ventricular histopathology with increased inflammatory cell infiltration, reduced expression of cardiac CHRM2, a cardioprotective cholinergic receptor, adaptive increases in AMPK and α7nAchR levels, and elevated levels of iNOS, NO, STAT3, JAK2, IL-6, TNF-α, and NF-κB. These effects were attenuated in rats treated with either low or high doses of MET. MET administration restored normal ECG recordings, diminished oxidative stress and inflammatory mediators, and downregulated NF-κB expression. Moreover, MET improved CHRM2 expression and normalized α7nAchR levels. Additionally, MET influenced the expression of key signaling molecules such as Akt, STAT3, and JAK2. SignificanceThese findings might suggest that MET exerts cardioprotective effects in ISOP-induced MI in rats by mitigating critical inflammatory signaling pathways and regulating protective cholinergic mechanisms in the heart.

Comparative Analysis of the Protective Effect of Naringenin on Cardiovascular Parameters of Normotensive and Hypertensive Rats Subjected to the Myocardial Infarction Model.

Background: Cardiovascular diseases rank as the top global cause of mortality, particularly acute myocardial infarction (MI). MI arises from the blockage of a coronary artery, which disrupts blood flow and results in tissue death. Among therapeutic approaches, bioactives from medicinal plants emerge as promising for the development of new medicines. Objectives: This study explored the effects of naringenin (NAR 100 mg/kg), a flavonoid found in citrus fruits, in normotensive (NTR) and spontaneously hypertensive (SHR) rats, both subjected to isoproterenol (ISO 85 mg/kg)-induced MI. Results: Post-treatment assessments indicated that NAR reduced blood pressure and minimized clot formation, particularly notable in the SHR group, which helps mitigate damage related to hypertension and ISO exposure. Additionally, NAR effectively restored KCl-induced contractility in the aortas of both NTR and SHR groups. NAR treatment reduced reduced glutathione (GSH) and lipid hydroperoxides (LOOH) values and recovered the activity of the antioxidant enzymes catalase (CAT) and glutathione-s-transferase (GST) in NTR groups. Moreover, myocardial damage assessed through histological analyses was reduced in groups treated with NAR. Conclusions: The results highlight significant pathophysiological differences between the groups, suggesting that NAR has protective potential against ISO-induced cardiac damage, warranting further investigation into its protective effects and mechanisms.

Long-term transcranial ultrasound stimulation regulates neuroinflammation to ameliorate post–myocardial infarction cardiac arrhythmia and remodeling

BackgroundSympathetic overactivation and neuroinflammation in the paraventricular nucleus (PVN) are crucial factors in post–myocardial infarction (MI) cardiac remodeling and ventricular arrhythmias (VAs). Prior study has indicated that low-intensity focused ultrasound stimulation could attenuate sympathetic neuroinflammation within the PVN to prevent the occurrence of VAs in an acute MI model. Meanwhile, the cGAS-STING pathway has shown potential to ameliorate the neuroinflammatory response. However, the effect and mechanisms of long-term transcranial ultrasound stimulation (LTUS) for modulating neuroinflammation in the chronic stage of MI remain unclear. ObjectiveThis study aimed to ascertain whether LTUS could mitigate post-MI neuroinflammation and improve cardiac arrhythmia and remodeling through the cGAS-STING pathway. MethodsThirty-six SD rats were equally randomized to the sham group (pseudo-MI modeling), chronic MI group (MI modeling), and LTUS group (MI modeling and long-term ultrasound stimulation). Transcranial ultrasound stimulation (15 min/d) was conducted on the PVN for 4 consecutive weeks. After 4-week intervention, echocardiography, electrophysiologic experiments, and histopathologic staining were performed to assess the role of LTUS on post-MI neuroinflammation and cardiac remodeling. ResultsThe results indicated that LTUS significantly facilitated microglial M1 to M2 polarization through the cGAS-STING signaling pathway within the PVN. Furthermore, LTUS inhibited MI-induced sympathetic neuroinflammation, thereby improving cardiac dysfunction, ameliorating cardiac remodeling, and reducing VA inducibility. ConclusionLong-term ultrasound stimulation of the PVN was found to alleviate post-MI neuroinflammation and to improve cardiac remodeling, which might inspire novel insights and clinical strategies for noninvasive neuromodulation and the treatment of post-MI VAs.

AAV9-mediated CIRP gene transfer protects against cardiac dysfunction and remodelling in a rat model of myocardial infarction.

Cold-inducible RNA-binding protein (CIRP) is a stress-response protein that has been shown to protect cardiomyocytes under a variety of stress conditions from apoptosis. Our recent study showed that the expression of CIRP protein in the heart was downregulated in patients with heart failure and an animal model of ischaemia heart failure, but its role in heart failure is still unknown. The present study aimed at evaluating the potential role of CIRP on the heart in an animal model of myocardial infarction (MI). MI model of rats was induced by the ligation of the left coronary artery. CIRP overexpression was mediated by direct intracardiac injection of adeno-associated virus serotype 9 (AAV9) vectors carrying a CIRP coding sequence with a cardiac-specific promoter before the induction of the MI model. The effects of CIRP elevation on MI-induced heart were analysed through echocardiographic, pathological and molecular analysis. Our results showed that the intracardiac injection of AAV9 successfully mediated CIRP upregulation in cardiomyocytes. Upregulation of cardiac CIRP prevented MI-induced cardiac dysfunction and adverse remodelling, coupled with the reduced inflammatory response in the heart. Collectively, these results demonstrated the beneficial role of intracellular CIRP on the heart and suggest that CIRP may be a therapeutic target in ischaemic heart disease.