Rat Model Of Myocardial Infarction Research Articles

Sequential Delivery of Cardioactive Drugs via Microcapped Microneedle Patches for Improved Heart Function in Post Myocardial Infarction Rats

After myocardial infarction, the heart undergoes adverse remodeling characterized by a series of pathological changes, including inflammation, apoptosis, fibrosis, and hypertrophy. In addition to cardiac catheter-based re-establishment of blood flow, patients typically receive multiple medications that aim to address these different mechanisms underlying left ventricular remodeling. The current study aims to establish a versatile multi-drug delivery platform for the controlled and sequential delivery of multiple therapeutic agents in a single treatment. Toward this goal, we generated a microcapped microneedle patch carrying methylprednisolone, interleukin-10, and vascular endothelial growth factor. In vitro characterization demonstrated a time-sequenced release pattern of these drug: methylprednisolone for the first 3 days, interleukin-10 from day 1 to 15, and vascular endothelial growth factor from day 3 to 25. The therapeutic effects of the microneedle patch were evaluated in a rat model of acute myocardial infarction induced by permanent ligation of left anterior descending coronary artery. Heart function was measured using trans-thoracic echocardiography. Heart inflammation, apoptosis, hypertrophy and angiogenesis were evaluated using histology. Our data indicated that, at 28 days after patch transplantation, animals receiving the microneedle patch with sequential release of these three agents showed reduced inflammation, apoptosis and cardiac hypertrophy compared to the animals receiving control patch without sequential release of these agents, which is associated with the improved angiogenesis and heart function. In conclusion, the microneedle patch can be utilized to deliver multiple therapeutic agents in a controlled and sequential manner that aligns with the pathological phases following myocardial infarction. STATEMENT OF SIGNIFICANCE: The post-myocardial infarction heart remodeling is characterized by a series of pathological events including acute inflammation, apoptosis, fibrosis, cardiac hypertrophy, and depressed heart function. In current clinical practice, multiple procedures and drugs given at different time points are necessary to combat these series of pathological events. In this study, we developed a novel microcapped microneedle patch for the controlled sequential delivery of triple cardioprotective drugs aiming to combat acute inflammation and cardiac hypertrophy, and promote angiogenesis. This study presents a comprehensive therapeutic approach, with the microneedle patch addressing multifaceted pathological processes during post-myocardial infarction left ventricular remodeling. This cardiac drug delivery system has the potential to improve patient treatment by delivering drugs in alignment with the series of time-dependent pathological phases following myocardial infarction, ultimately improving clinical outcomes.

Pretreatment with Notoginsenoside R1 enhances the efficacy of neonatal rat mesenchymal stem cell transplantation in model of myocardial infarction through regulating PI3K/Akt/FoxO1 signaling pathways

BackgroundAlthough stem cell transplantation is a promising approach for the treatment of myocardial infarction (MI), there are still some problems faced such as the low survival rate of stem cells. Here, we investigated the role of Notoginsenoside R1 (NGR1) pretreatment in improving the effects of neonatal rat bone marrow mesenchymal stem cell (MSC) transplantation for treatment of MI.MethodsCardiac functions were detected by echocardiography and the myocardial infarct size was determined by Masson’s trichrome staining in a rat model of MI. The cardioprotective effects of NGR1/LY294002 co-pretreated MSCs was evaluated to explore the underlying mechanism. The angiogenesis was determined by vWF and α-SMA immunofluorescence staining and cell apoptosis was detected by TUNEL. In vitro, the effects of NGR1 on stem cell proliferation was examined by CCK-8 and levels of P-Akt, P-CREB, P-FoxO1 were detected by western blot. Apoptosis, ROS content, and cytokine levels were examined by DAPI and TUNEL staining, a ROS assay kit, and ELISA, respectively.ResultsNGR1 elevated the therapeutic effect of MSC transplantation on infarction by preserving cardiac function, increasing angiogenesis and expressions of IGF-1, VEGF, and SDF-1, and reducing cell apoptosis, whereas the addition of LY294002 prior to NGR1 treatment significantly counteracted the foregoing effects of NGR1. NGR1 pretreatment and SC79 pretreatment were similar in that both significantly increased P-Akt and P-FoxO1 levels in MSC and did not affect P-CREB levels. Besides, both NGR1 and SC79 promoted VEGF, SCF and bFGF levels in MSC cultures, and significantly reduced ROS accumulation and the attenuated cell apoptosis in MSC triggered by H2O2. Similarly, addition of LY294002 before NGR1 treatment significantly counteracted the aforementioned effects of NGR1 in vitro.ConclusionsNGR1 pretreatment enhances the effect of MSC transplantation for treatment of MI through paracrine signaling, and the mechanism underlying this effect may be associated with PI3K/Akt/FoxO1 signaling pathways.

Intervening to Preserve Function in Ischemic Cardiomyopathy with a Porous Hydrogel and Extracellular Matrix Composite in a Rat Myocardial Infarction Model.

Multiple hydrogels are developed for injection therapy after myocardial infarction, with some incorporating substances promoting tissue regeneration and others emphasizing mechanical effects. In this study, porosity and extracellular matrix-derived digest (ECM) are incorporated, into a mechanically optimized, thermoresponsive, degradable hydrogel (poly(N-isopropylacrylamide-co-N-vinylpyrrolidone-co-MAPLA)) and evaluate whether this biomaterial injectate can abrogate adverse remodeling in rat ischemic cardiomyopathy. After myocardial infarction, rats are divided into four groups: NP (non-porous hydrogel) without either ECM or porosity, PM (porous hydrogel) from the same synthetic copolymer with mannitol beads as porogens, and PME with porosity and ECM digest added to the synthetic copolymer. PBS injection alone is a control group. Intramyocardial injections occurred 3 days after myocardial infarction followed by serial echocardiography and histological assessments 8 weeks after infarction. Echocardiographic function and neovascularization improved in the PME group compared to the other hydrogels and PBS injection. The PME group also demonstrated improved LV geometry and macrophage polarization (toward M2) compared to PBS, whereas differences are not observed in the NP or PM groups versus control. These results demonstrate further functional improvement may be achieved in hydrogel injection therapy for ischemic cardiomyopathy by incorporating porosity and ECM digest, representing combined mechanical and biological effects.

Evaluation of 18F FOL a PET tracer targeting folate receptor beta in a rat model of myocardial infarction

Abstract Background Expression of folate receptor-β (FR-β) on the activated macrophages is associated with inflammatory diseases. However, the role of FR-β in the immune response following myocardial infarction (MI) remains unknown. Purpose To investigate FR-β-targeted positron emission tomography (PET) tracer aluminium fluoride-18-labeled 1,4,7,-triazacylononane-1,4,7-triacetic acid conjugated folate ([18F]FOL) for imaging immune response in a rat model of MI. Methods Rats underwent PET scan from 20 to 40 minutes after injection of 50±6 MBq of [18F]FOL on 3 (n=6), 7 (n=21), 15 (n=9), and 90 (n=11) days after surgical ligation of the left coronary artery. As controls, rats were studied on 3 (n=6), 7 (n=14), 15 (n=5), and 90 (n=8) days after sham-operation. [18F]FDG PET was performed a day before [18F]FOL injection in order to localize myocardium and area of MI. After [18F]FOL PET, autoradiography, histology, and staining of CD68 were performed 3 (n=6), 7 (n=6), and 90 (n=11) days after MI in order to detect [18F]FOL uptake and activated macrophages in myocardial tissue sections. A subgroup of rats (n=15) underwent serial [18F]FOL PET 7 and 90 days after MI together with echocardiography in order to evaluate left ventricular function. Results The presence of MI was confirmed by histology in all rats after coronary ligation. PET images showed increased uptake of [18F]FOL in the area of MI. The uptake was significantly higher (p<0.001) in the area of MI than in the myocardium of sham-operated rats on day 3 (SUV 2.04±0.25 vs. 0.74±0.12), and remained increased on day 7 (SUV 1.39±0.33 vs. 0.68±0.12), day 15 (SUV 1.24±0.20 vs. 0.59±0.07), and day 90 (SUV 1.39±0.25 vs. 0.69±0.11). On day 3, pre-treatment with folate glucosamine (n=3) reduced the [18F]FOL signal by 50% in the area of MI indicating specific binding to FR-β. Autoradiography confirmed focally increased uptake of [18F]FOL in the area of MI. A positive correlation was found between uptake of [18F]FOL in PET images and areal percentage of CD68-positivity in the area of MI (r2=0.447, p<0.001). Uptake of [18F]FOL on day 7 after MI was associated with decline in left ventricular ejection fraction (R=-0.665, p<0.01) and increase in left ventricular systolic volume (R=0.561, p=0.02) between 7 and 90 days after MI. Conclusion Cardiac [18F]FOL PET detects increased macrophage-associated FR-β expression after MI in a rat model. FR-β expression peaks early and remains elevated up to 3 months in the infarcted area. Increased FR-β expression early after MI is associated with worsening of left ventricular systolic function late after MI.

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

Investigation of the usefulness of collagen peptide in intramyocardial injection of human iPS cell-derived cardiomyocytes

Abstract Background Injecting human induced pluripotent stem (iPS) cell-derived cardiomyocytes directly into the heart muscle holds promise as a treatment for heart failure. Achieving better engraftment is crucial for maximizing therapeutic effectiveness. Collagen peptide (CP) is a form of hydrolyzed gelatin known for its resistance to solidification. By adjusting its concentration, the viscosity of CP can be easily managed, potentially influencing the retention and engraftment efficiency of transplanted cells. Purpose We investigated the impact of different CP concentrations as a solvent for intramyocardial injection of human iPS cell-derived cardiomyocytes. Methods Initially, we examined the leakage of CP solution from the injection site using chicken meat and ex vivo rat heart. Subsequently, an in vivo experiment was conducted using beating rat myocardium injected with CP solution and Indian ink to assess CP diffusion in dynamic heart tissue. Finally, we performed intramyocardial injections of human iPS cell-derived cardiomyocytes onto a myocardial infarction model in immunosuppressed rats (1.0×107 cells/rat), followed by echocardiographic evaluation of cardiac function four weeks post-transplantation (N=3-6). Results There was less leakage from the injection site at lower CP concentration (10%) compared to higher concentration (20%), particularly in chicken or ex vivo rat heart tissue under static, non-beating conditions (chicken; 10% vs. 20% CP: 3.2±0.7% vs. 11.6±0.8%, P=0.01 / rat heart; 1.5±0.9% vs. 6.8±1.1%, P=0.0072). However, when examining fluid leakage from the cross-section of ex vivo rat hearts, we observed significantly higher leakage, regardless of CP concentration (10% CP: 45.7±2.7%, 20% CP: 59.1±8.1%), suggesting that CP diffusion within myocardial tissues had a greater influence on local retention than leakage from the injection site. Subsequently, in an experiment using beating rat myocardium and Indian ink, we observed significant suppression of diffusion in tissues treated with CP solution, with the 20% concentration showing a tendency to remain at the injection site (0% CP: 24.5±6.2 mm2, 10% CP: 6.9±7.1 mm2, 20% CP: 10.6±3.3 mm2, P=0.005). This indicates that 20% CP, rather than 10% CP, may be more suitable for local retention in tissues experiencing intra-tissue pressure, such as the beating myocardium. Finally, in vivo experiment using a myocardial infarction model of rat, there was no significant difference in left ventricular ejection fraction (LVEF) when cardiomyocytes were transplanted with 10% CP (0％ CP: 56.1±8.9%, 10%CP: 61.9±5.2%, P=0.92). However, there was a trend towards improved LVEF with the 20% CP solution (0% CP: 56.1±8.9%, 20%CP: 68.8±7.9%, P=0.13), Conclusion Twenty-percent CP may be more beneficial for treating myocardial ischemia due to enhanced retention and engraftment of transplanted cardiomyocytes.

A personalized, 3D printed, polymeric elastic support device for the prevention of post-MI cardiac remodeling

Abstract Introduction Myocardial remodeling and dilatation following myocardial infarction (MI) initiates a vicious cycle leading to heart failure (HF). The anatomy and pathophysiology of every patient is unique. We have developed a 3D printed, biopolymer based personalized Elastic Support Device, that is 3D printed based on patient’s imaging, aiming to restore cardiac physiology. This study aimed to assess the device on rat MI model. Materials and Methods MI was induced in 24 Sprague Dawley rats by permanently ligating the mid LAD artery via midline sternotomy cut. Twelve animals underwent immediate implantation of the elastic support device that was pre-printed from animal specific 3D echocardiography. The animals were followed up with echocardiography at days -2, 7, 14, 28. The animals were sacrificed at day 28, cardiac tissue and plasma were taken for further histological and biochemical analysis. Results and discussion Mortality was similar at both groups (5 vs 4 in the device and control groups respectively). Ejection fraction reduced in both groups from a baseline of 61.9±8.9% to 47.5±12.7%. Left Ventricular End Diastolic Diameter increased from baseline to day 28 in the control (7.0±0.56mm vs 7.7±1mm) but not the device group (6.87±0.2mm vs 6.93±1.1mm, p<0.05). Parameters of diastolic function such as E/E’ were similar in both groups throughout the follow-up. Mason’s Trichrome stained cardiac sections revealed improved infarct size at the device group (7.4±1.9% vs. 10.6±2.8%) and lower overall cardiac fibrosis. Conclusion In this preliminary small animal model study, the capability to 3D print and implant an imaging based, personalized, 3D printed elastic support device. The cardiac diastolic function was not impaired, and no safety issues were noticed. Furthermore, cardiac dilatation was prevented, and infarct size was reduced.Trial design and results

Evaluating the diagnostic potential of SOCS3 in copper metabolism for acute myocardial infarction

Acute myocardial infarction (AMI) represents a critical cardiovascular condition necessitating rapid and precise diagnostic strategies. This study investigates the diagnostic implications of genes involved in copper metabolism homeostasis in AMI. We identified genes related to copper metabolism and AMI from Genecards and GEO databases, conducting differential gene analysis via R software. Gene function was annotated through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, while the STRING database facilitated key gene identification via topological analysis. The diagnostic value of these genes, particularly cytokine signaling 3 (SOCS3), was assessed using ROC curve analysis. SOCS3 expression was validated using in-vitro and in-vivo models, including cardiomyocyte hypoxia/reoxygenation (H/R) and rat myocardial infarction (MI) model. Further, we examined the effects of SOCS3 knockout on cell proliferation, apoptosis, and myocardial infarction severity. 77 genes were identified, with 73 showing upregulation and 4 downregulation. These genes mainly participated in pathways related to cytokine activation, inflammation regulation, and lipid metabolism. Network analysis highlighted 10 key genes, with SOCS3 exhibiting significant diagnostic potential (AUC > 0.9). Validation experiments confirmed SOCS3 overexpression in disease models, with its knockout leading to decreased apoptosis, reduced infarct size, and improved cardiac function. This study highlights the diagnostic relevance of genes associated with copper metabolism, particularly SOCS3, in AMI. These findings offer novel insights into the molecular mechanisms of AMI, supporting the development of targeted diagnostic and therapeutic strategies.

Integration of four-dimensional proteomics and network pharmacology to reveal molecular mechanisms of multi-components multi-targets effects of Sini decoction on myocardial infarction

Sini Decoction (SND) has been proven to be an effective formula to alleviate cardiac injury of myocardial infarction (MI). However, the potential mechanism of SND remains unclear. In this study, the MI rat model was established by ligating the left anterior descending coronary artery. A total of 17 SND-distributed components in heart were identified by using ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOFMS). The combination of four-dimensional (4D) proteomics and network pharmacology was employed to find the potential targets for therapeutic intervention, and molecular docking and cellular thermal shift assay (CETSA) were used to reveal the interactions between the potential targets and the potential active components distributed in heart of SND. 33 SND-effected proteins were identified by 4D proteomics, which was involved in carbon metabolism, fatty acid metabolism, valine, leucine and isoleucine degradation, tricarboxylic acid (TCA) cycle and PPAR signaling pathway. 17 potential SND-targeted direct proteins were screened by comparing SND-effected proteins generated from 4D proteomics with the MI-related proteins obtained from disease database. The potential relationships between 17 components and 17 potential SND-targeted direct proteins were established by molecular docking analysis, in which songorine, benzoylhypaconine, hypaconine, formononetin, and liquiritigenin could be bound to the surrounding amino acid residues in the binding pocket of Mtor, Parp1, Acadm, Crat, and Aldh2. Then, CETSA analysis further confirmed that songorine and benzoylhypaconine could increase the heat stability of Mtor and Parp1 in cardiac tissue lysate, respectively, which suggested that there existed direct interactions between songorine and Mtor, and benzoylhypaconine and Parp1. In summary, this work concluded that SND produced cardioprotective effects mainly through preserving energy metabolism, also demonstrated that the combination of 4D proteomics and network pharmacology was a promising tool for uncovering the molecular mechanisms of multi-components multi-targets effects of TCM.

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.

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.

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.

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.

The Possible Therapeutic Role of MSC Derived Exosomes Extracted from Myocardial Infarction versus Healthy Rat Models in the Heart with Surgically Occluded Right Anterior Coronary Artery in Rats A Histological Study

Abstract Introduction Myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary arteries of the heart, causing damage to the heart Muscle. The most common symptom is chest pain or discomfort which may travel into the shoulder, arm, back, neck or jaw. Often it occurs in the center or left side of the chest and lasts for more than a few minutes. MI may cause heart failure, an irregular heartbeat, cardiogenic Shock or cardiac arrest. Aim: this study is designed to compare between the therapeutic role of autologous exosomes versus homologous exosomes on surgically induced myocardial infarction model in adult male albino rats. Material and Methods Fifty adult male albino rats weighing 150–250 gm were included with age from 8 to 11 old months in the study. In addition, ten rats weighing 150 gm with age from 7 to 8 old weeks were used for adipose derived exosomes preparation. The rats were divided into the following three groups: Group I: control group, Group II: myocardial infarction group; rats were subjected to right (RACO Technique), Group III: rats were subjected to permanent RACO technique as in group II then rats were further subdivided into two subgroups; Subgroup IIIa received autologous exosomes in tail vein on the 2nd day of the experiment and Subgroup IIIb received homologous exosomes in tail vein on the 2nd day of the experiment. Results Group II showed disruption of cardiomyoctes which appeared deeply acidophilic and darkly stained nuclei with loss of the intercalated discs and muscle striations. Immunohistochemical stain revealed a significantly increased reaction to iNOS antibodies, caspase-3 antibodies, anti -PCNA and positive anti-VEGF in comparison to control group. Group III; including subgroups IIIa and IIIb; showed preservation of the myocardium integrity. However, subgroup IIIa revealed significant increase in anti-VEGF and decrease in iNOS antibodies as compared to subgroup IIIb. Conclusion Both exosomes from healthy rats and exosomes from rats with MI showed therapeutic and anti-inflammatory effects in surgically induced MI. These effects were more prominent in exosomes from rats with MI than healthy rats as detected by microscopic, morphometric, and statistical studies.

Treatment with a combination of myricitrin and exercise alleviates myocardial infarction in rats via suppressing Nrf2/HO-1 antioxidant pathway

Myocardial infarction (MI) is the primary source of death in cardiovascular diseases. Myricitrin (MYR) is a phenolic compound known for its antioxidant properties. This study aimed to investigate the impact of MYR alone or combined with exercise on a rat model of MI and its underlying mechanism. Sprague-Dawley rats were randomized into 5 groups: sham-operated (Sham), MI-sedentary (MI-Sed), MI-exercise (MI-Ex), MI-sedentary + MYR (MI-Sed-MYR) and MI-exercise + MYR (MI-Ex-MYR). MI was induced through ligation of left anterior descending coronary artery. The treatment with exercise or MYR (30 mg/kg/d) gavage began one week after surgery, either individually or in combination. After 8 weeks, the rats were assessed for cardiac function. Myocardial injuries were estimated using triphenyltetrazolium chloride, sirius red and Masson staining. Changes in reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm), apoptosis and Nrf2/HO-1 pathway were analyzed by ROS kit, JC-1 kit, TUNEL assay, Western blot and immunohistochemistry. Both MYR and exercise treatments improved cardiac function, reduced infarct size, suppressed collagen deposition, and decreased myocardial fibrosis. Additionally, both MYR and exercise treatments lowered ROS production induced by MI, restored ΔΨm, and attenuated oxidative stress and apoptosis in cardiomyocytes. Importantly, the combination of MYR and exercise showed greater efficacy compared to individual treatments. Mechanistically, the combined intervention activated the Nrf2/HO-1 signaling pathway. These findings suggest that the synergistic effect of MYR and exercise may offer a promising therapeutic approach for alleviating MI.

Molecular insight of miRNA-217 role in the pathogenesis of myocardial infarction: Promising diagnostic biomarker and therapeutic target

BackgroundGlobally, myocardial infarction (MI) is one of the main causes of death. This study aims to investigate the role of miR-217 in the pathogenesis through targeting MAPK and PI3K/AKT signaling pathways in experimental model of myocardial infarction and studying the possible cardioprotective role of dihydromyricetin (DHM) through modulation of this pathway. MethodsDihydromyricetin was injected (100 mg/kg; p.o.) in isoprenaline induced myocardial infarction rat model for 14 days. Rats were anaesthetized and blood samples were taken for serum separation, estimation of creatine kinase-MB (CK-MB), and troponin-I levels after 24 h had passed since the last isoprenaline injection. In addition, the hearts were also used for the other biochemical studies and the histological evaluation. ResultsDHM resulted in a significant suppression of the elevated levels miR-217 and MAPK compared to the MI control group and restored the normal level of serum CK-MB. Furthermore, DHM successfully restored the oxidative balance and halted the pro-inflammatory mediators in the cardiac tissue. ConclusionAccordingly, our experiment emphasizes the anti-ischemic property that has been demonstrated through modulation of expression level of miR-217 and consequent deactivation of MAPK and PI3K/AKT signaling pathways, and this was assured by halting downstream pro-inflammatory markers.

17β-Estradiol Nanoparticles Increase Endothelial Nitric Oxide Synthase Expression Through Akt Pathway in Rats with Myocardial Infarction

17β-estradiol can effectively slow down progression of myocardial infarction (MI), and is expected to have more curative effects. Therefore, this study investigated the mechanism underlying cardioprotective role of 17β-estradiol NPs in rats with MI. After construction of rat MI model and preparation of 17β-estradiol NPs, the rats were administered with 17β-estradiol alone, 17β-estradiol NPs and Akt agonist or inhibitor. Distribution of 17β-estradiol NPs was observed by fluorescence microscope and release curve was detected. After treatment, echocardiography was conducted to measure the cardiac function indicators. With HE staining to observe myocardial tissue, RT-qPCR and Western blot determined levels of AKT and eNOS. The NPs were relatively uniform in size and round in shape; and cumulative release rate and concentration of 17β-estradiol in rats reached highest level on 30th day. Treatment with 17β-estradiol or 17β-estradiol NPs importantly increased survival rate of MI rats and decreased MI area while improving LVSP, LVDP, and HR. Moreover, the 17β-estradiol NPs had the smallest MI area. The myocardial tissue of rats in the 17β-estradiol NP group was closely arranged, and myocardial collagen was significantly reduced. The 17β-estradiol NPs increased the mRNA level of eNOS and Akt when eNOS expression was related to Akt expression. 17β-estradiol NPs can therefore increase the expression of eNOS by activating Akt signaling pathway, thereby relieving the myocardial injury in rats, hindering progression of MI.

In Silico and In Vivo Studies of β-Sitosterol Nanoparticles as a Potential Therapy for Isoprenaline-Induced Cognitive Impairment in Myocardial Infarction, Targeting Myeloperoxidase.

This study aimed to compare the effects of β-sitosterol nanoparticles (BETNs) and β-sitosterol (BET) on cognitive impairment, oxidative stress, and inflammation in a myocardial infarction (MI) rat model using in silico and in vivo methods. β-Sitosterol (BET) and myeloperoxidase (MPO) ligand-receptor binding affinities were evaluated using Autodock Vina for docking and Gromacs for dynamics simulations. BET nanoparticles, prepared via solvent evaporation, had their size confirmed by a nanoparticle analyzer. ISO-induced cognitive impairment in rats was assessed through Morris water maze and Cook's pole climbing tests. Oxidative stress, inflammation, and cardiac injury were evaluated by measuring GSH, SOD, MDA, MPO, CkMB, LDH, lipid profiles, and ECGs. Histopathology of the CA1 hippocampus and myocardial tissue was performed using H&E staining. In silico analyses revealed strong binding affinities between BET and MPO, suggesting BET's potential anti-inflammatory effect. BETN (119.6 ± 42.6 nm; PDI: 0.809) significantly improved MI-induced cognitive dysfunction in rats (p < 0.001 ***), increased hippocampal GSH (p < 0.01 **) and SOD (p < 0.01 **) levels, and decreased hippocampal MDA (p < 0.05 *) and MPO levels (p < 0.01 **). BETNs also elevated cardiac GSH (p < 0.01 **) and SOD (p < 0.01 **) levels and reduced cardiac MPO (p < 0.01 **), CkMB (p < 0.001 **) and LDH (p < 0.001 **) levels. It restored lipid profiles, normalized ECG patterns, and improved histology in the hippocampal CA1 region and myocardium. Compared with BET treatment, BETNs were more effective in improving cognitive impairment, oxidative damage, and inflammation in MI rats, suggesting its potential in treating cognitive dysfunction and associated pathological changes in MI.

Endogenous adenine is a potential driver of the cardiovascular-kidney-metabolic syndrome.

Mechanisms underlying the cardiovascular-kidney-metabolic (CKM) syndrome are unknown, although key small molecule metabolites may be involved. Bulk and spatial metabolomics identified adenine to be upregulated and specifically enriched in coronary blood vessels in hearts from patients with diabetes and left ventricular hypertrophy. Single nucleus gene expression studies revealed that endothelial methylthioadenosine phosphorylase (MTAP) was increased in human hearts with hypertrophic cardiomyopathy. The urine adenine/creatinine ratio in patients was predictive of incident heart failure with preserved ejection fraction. Heart adenine and MTAP gene expression was increased in a 2-hit mouse model of hypertrophic heart disease and in a model of diastolic dysfunction with diabetes. Inhibition of MTAP blocked adenine accumulation in the heart, restored heart dysfunction in mice with type 2 diabetes and prevented ischemic heart damage in a rat model of myocardial infarction. Mechanistically, adenine-induced impaired mitophagy was reversed by reduction of mTOR. These studies indicate that endogenous adenine is in a causal pathway for heart failure and ischemic heart disease in the context of CKM syndrome.

Advancing Myocardial Infarction Treatment: Harnessing Multi-Layered Recellularized Cardiac Patches with Fetal Myocardial Scaffolds and Acellular Amniotic Membrane.

Myocardial infarction (MI) is a leading cause of irreversible functional cardiac tissue loss, requiring novel regenerative strategies. This study assessed the potential therapeutic efficacy of recellularized cardiac patches, incorporating fetal myocardial scaffolds with rat fetal cardiomyocytes and acellular human amniotic membrane, in adult Wistar rat models of MI. Decellularized myocardial tissue was obtained from 14 to 16 week-old human fetuses that had been aborted. Chemical detergents (0.1% EDTA and 0.2% sodium dodecyl sulfate) were used to prepare the fetal extracellular matrix (ECM), which was characterized for bio-scaffold microstructure and biocompatibility via scanning electron microscopy (SEM) and MTT assay, respectively. Neonatal cardiomyocytes were extracted from the ventricles of one-day-old Wistar rats' littermates and characterized through immunostaining against Connexin-43 and α-smooth muscle actin. The isolated cells were seeded onto decellularized tissues and covered with decellularized amniotic membrane. Sixteen healthy adult Wistar rats were systematically allocated to control and MI groups. MI was induced via arterial ligation. Fourteen days post-operation, the MI group was received the engineered patches. Following a two-week post-implantation period, the animals were euthanized, and the hearts were harvested for the graft evaluation. Histological analysis, DAPI staining, and ultra-structural examination corroborated the successful depletion of cellular elements, while maintaining the integrity of the fetal ECM and architecture. Subsequent histological and immunohistochemichal (IHC) evaluations confirmed effective cardiomyocyte seeding on the scaffolds. The application of these engineered patches in MI models resulted in increased angiogenesis, reduced fibrosis, and restricted scar tissue formation, with the implanted cardiomyocytes remaining viable at graft sites, indicating prospective in vivo cell viability. This study suggests that multi-layered recellularized cardiac patches are a promising surgical intervention for myocardial infarction, showcasing significant potential by promoting angiogenesis, mitigating fibrosis, and minimizing scar tissue formation in MI models. These features are pivotal for enhancing the therapeutic outcomes in MI patients, focusing on the restoration of the myocardial structure and function post-infarction.