Animal Models Of Myocardial Infarction Research Articles

Functional Gene Module-Based Identification of Phillyrin as an Anticardiac Fibrosis Agent.

Cardiac fibrosis (CF) greatly influences the therapeutic effects of heart diseases and remains an urgent challenge in clinical therapy. Till now, only a few methods are used to find potential anti-CF drugs effectively. This study aimed to construct a gene functional module to represent the core pathological process of CF and screen antifibrotic agents capable of decreasing the expression of the gene functional module. First, three CF marker genes Postn, Ddr2, and Pdgfra were selected to identify the corresponding highest coexpressed genes in the genome-based transcriptional profiles of human hearts. Both the marker genes and the coexpressed genes formed the CF-related gene functional module. Second, the correlation of the module with the CF process was measured in a collection of gene expression profiles of heart diseases to evaluate the participation of the functional module in heart diseases. Third, the anti-CF effects of phillyrin were predicted by the enrichment analysis of the module in the phillyrin-induced transcriptional profile. Finally, the myocardial infarction animal model was used to validate the cardioprotective and anti-CF effects of phillyrin experimentally. The results showed that phillyrin was a novel antifibrotic agent in heart diseases.

Exosomal miR-25-3p from mesenchymal stem cells alleviates myocardial infarction by targeting pro-apoptotic proteins and EZH2

Mesenchymal stem cell (MSC) therapy is a promising approach against myocardial infarction (MI). Studies have demonstrated that MSCs can communicate with other cells by secreting exosomes. In the present study, we aimed to identify exosomal microRNAs that might contribute to MSC-mediated cardioprotective effects. Primary cardiomyocytes were deprived of oxygen and glucose to mimic MI in vitro. For the animal model of MI, the left anterior descending artery was ligated for 1 h, followed by reperfusion for 12 h. MSC-derived exosomes were used to treat primary cardiomyocytes or mice. Cardioprotection-related microRNAs were determined, followed by target gene identification and functional studies with quantitative PCR, western blotting, MTT assay, flow cytometry assay, chromatin immunoprecipitation and dual-luciferase assay. We found that MSC co-culture reduced OGD-induced cardiomyocyte apoptosis and inflammatory responses. Cardioprotection was also observed upon treatment with MSC-derived exosomes in vitro and in vivo. In line with this, exosome uptake led to a significant increase in miR-25-3p in cardiomyocytes. Depletion of miR-25-3p in MSCs abolished the protective effects of exosomes. Mechanistically, miR-25-3p directly targeted the pro-apoptotic genes FASL and PTEN and reduced their protein levels. Moreover, miR-25-3p decreased the levels of EZH2 and H3K27me3, leading to derepression of the cardioprotective gene eNOS as well as the anti-inflammatory gene SOCS3. Inhibition of EZH2 or overexpression of miR-25-3p in cardiomyocytes was sufficient to confer cardioprotective effects in vitro and in vivo. We concluded that exosomal miR-25-3p from MSCs alleviated MI by targeting pro-apoptotic proteins and EZH2.

Cardioprotective effect of Yiqi Huoxue granule through regulation of mitophagy after myocardial infarction in rats

To investigate the cardioprotective effect of Yiqi Huoxue granule (YQHXG) in the regulation of autophagy in rats induced with myocardial infarction (MI). An acute MI animal model was established by ligation of the left anterior descending branch of the coronary artery in Sprague-Dawley rats. Besides, 20 rats received sham operation were classified into a control group. The remaining 59 rats were randomly divided into MI model group (n = 19), YQHXG group (n = 20), and perindopril group (n = 20). Relevant indicators on days 7 and 28 were observed in each group. Left ventricular function was determined by echocardiography. The structure and morphology of mitochondria, and the number of autophagic vesicles, were observed by transmission electron microscopy. The mRNA and protein expression levels of LC3, FUNDC1, Beclin-1, and BNIP3 were examined in the tissue of the MI marginal area. Compared with the MI model group, YQHXG showed obvious improvements in cardiac functions. Observing the microscopic morphology of the heart tissue, myocardial tissue damage attenuated, autophagic signs of autophagosomes and autolysosomes reduced, vacuolization in mitochondria mitigated, and mitochondria arranged in order. YQHXG could reduce the degree of tissue lesion after MI and regulate the expression of autophagy-related molecules at different stages. On Day 7, YQHXG significantly downregulated the expression of Fundc1 , Becn1 , Bnip3 mRNA and reduced the levels of FUNDC1, Beclin-1, BNIP3, and LC3 B proteins expression (all P < .001). On Day 28, YQHXG could upregulate the expression of Becn1 , Fundc1 and Bnip3 mRNA and increased the levels of the corresponding proteins expression (all P < .001). Besides, it also increased LC3 B protein expression level ( P = . 0344). YQHXG regulated the expression of mitochondrial autophagy-related factors in myocardial tissue and mitochondrial autophagic activity at different stages to protect the heart following MI.

Engineered M13 Peptide Carrier Promotes Angiogenic Potential of Patient-Derived Human Cardiac Progenitor Cells and In Vivo Engraftment.

Despite promising advances in stem cell-based therapy, the treatment of ischemic cardiovascular diseases remains a big challenge due to both the insufficient in vivo viability of transplanted cells and poor angiogenic potential of stem cells. The goal of this study was to develop therapeutic human cardiac progenitor cells (hCPCs) for ischemic cardiovascular diseases with a novel M13 peptide carrier. In this study, an engineered M13 peptide carrier was successfully generated using a QuikChange Kit. The cellular function of M13 peptide carrier-treated hCPCs was assessed using a tube formation assay and scratch wound healing assay. The in vivo engraftment and cell survival bioactivities of transplanted cells were demonstrated by immunohistochemistry after hCPC transplantation into a myocardial infarction animal model. The engineered M13RGD+SDKP peptide carrier, which expressed RGD peptide on PIII site and SDKP peptide on PVIII site, did not affect morphologic change and proliferation ability in hCPCs. In contrast, hCPCs treated with M13RGD+SDKP showed enhanced angiogenic capacity, including tube formation and migration capacity. Moreover, transplanted hCPCs with M13RGD+SDKP were engrafted into the ischemic region and promoted in vivo cell survival. Our present data provides a promising protocol for CPC-based cell therapy via short-term cell priming of hCPCs with engineered M13RGD+SDKP before cell transplantation for treatment of cardiovascular disease.

Effect of remote ischaemic conditioning on platelet reactivity and endogenous fibrinolysis in ST-elevation myocardial infarction: a substudy of the CONDI-2/ERIC-PPCI randomized controlled trial.

Remote ischaemic conditioning (RIC) has been shown to reduce myocardial infarct size in animal models of myocardial infarction. Platelet thrombus formation is a critical determinant of outcome in ST-segment elevation myocardial infarction (STEMI). Whether the beneficial effects of RIC are related to thrombotic parameters is unclear. In a substudy of the Effect of Remote Ischaemic Conditioning on clinical outcomes in STEMI patients undergoing Primary Percutaneous Coronary Intervention (ERIC-PPCI) trial, we assessed the effect of RIC on thrombotic status. Patients presenting with STEMI were randomized to immediate RIC consisting of an automated autoRIC™ cuff on the upper arm inflated to 200 mmHg for 5 min and deflated for 5 min for four cycles (n = 53) or sham (n = 47). Venous blood was tested at presentation, discharge (48 h) and 6-8 weeks, to assess platelet reactivity, coagulation, and endogenous fibrinolysis using the Global Thrombosis Test and thromboelastography. Baseline thrombotic status was similar in the two groups. At discharge, there was some evidence that the time to in vitro thrombotic occlusion under high shear stress was longer with RIC compared to sham (454 ± 105 s vs. 403 ± 105 s; mean difference 50.1 s; 95% confidence interval 93.7-6.4, P = 0.025), but this was no longer apparent at 6-8 weeks. There was no difference in clot formation or endogenous fibrinolysis between the study arms at any time point. RIC may reduce platelet reactivity in the first 48 h post-STEMI. Further research is needed to delineate mechanisms through which RIC may reduce platelet reactivity, and whether it may improve outcomes in patients with persistent high on-treatment platelet reactivity.

CHIR99021 and fibroblast growth factor 1 enhance the regenerative potency of human cardiac muscle patch after myocardial infarction in mice

BackgroundWe have shown that genetic overexpression of cell cycle proteins can increase the proliferation of transplanted cardiomyocytes derived from human induced-pluripotent stem cells (hiPSC-CMs) in animal models of myocardial infarction (MI). Here, we introduce a new, non-genetic approach to promote hiPSC-CM cell cycle activity and proliferation in transplanted human cardiomyocyte patches (hCMPs). MethodsMice were randomly distributed into 5 experimental groups (n = 10 per group). One group underwent Sham surgery, and the other 4 groups underwent MI induction surgery followed by treatment with hCMPs composed of hiPSC-CMs and nanoparticles that contained CHIR99021 and FGF1 (the NPCF-hCMP group), with hCMPs composed of hiPSC-CMs and empty nanoparticles (the NPE-hCMP group); with patches containing the CHIR99021/FGF-loaded nanoparticles but lacking hiPSC-CMs (the NPCF-Patch group), or patches lacking both the nanoparticles and cells (the E-Patch group). Cell cycle activity was evaluated via Ki67 and Aurora B expression, bromodeoxyuridine incorporation, and phosphorylated histone 3 levels (immunofluorescence); engraftment via human cardiac troponin T or human nuclear antigen expression (immunofluorescence) and bioluminescence imaging; cardiac function via echocardiography; infarct size and wall thickness via histology; angiogenesis via isolectin B4 expression (immunofluorescence); and apoptosis via TUNEL and caspace 3 expression (immunofluorescence). ResultsCombined CHIR99021- and FGF1-treatment significantly increased hiPSC-CM cell cycle activity both in cultured cells (by 4- to 6-fold) and in transplanted hCMPs, and compared to treatment with NPE-hCMPs, NPCF-hCMP transplantation increased hiPSC-CM engraftment by ~4-fold and was associated with significantly better measurements of cardiac function, infarct size, wall thickness, angiogenesis, and hiPSC-CM apoptosis four weeks after MI induction. ConclusionsNanoparticle-mediated CHIR99021 and FGF1 delivery promotes hiPSC-CM cell cycle activity and proliferation, as well as the engraftment and regenerative potency of transplanted hCMPs, in a mouse MI model.

Mesenchymal Stem Cell Therapy for Patients with Ischemic Heart Failure- Past, Present, and Future.

The prevalence of Heart Failure (HF) has increased over time. Ischemic heart failure accounts for 50% of HF, which results from ischemic coronary heart diseases such as Myocardial Infarction (MI). Conventionally, reduction of cardiac load and revascularization partially increase cardiomyocyte survival and preserve cardiac functions. Nevertheless, how to improve cardiomyocyte rescue and prevent HF progression remain as challenges. Mesenchymal Stem Cells (MSCs) are multipotent stem cells that give rise to various lineages. The administration of MSCs promotes cardiomyocyte survival and improves cardiac functions in animal models of MI and patients with ischemic cardiomyopathy. However, after injection, MSCs persist for a very short time, indicating that the prolonged protective effects of MSCs on cardiomyocytes may be mediated by paracrine functions of MSCs, such as exosomes. In this review, we focus on MSC-derived exosomes in cardiomyocyte protection to facilitate future applications of exosomes in HF treatment.

Targeting the Main Anatomopathological Features in Animal Models of Myocardial Infarction

Cardiovascular disease is the leading cause of human mortality and disability worldwide, primarily due to myocardial infarction (MI) and the resultant heart failure. To address this, animal models of MI have been developed to better understand the pathophysiological process and to enable the discovery and development of new therapies. The most commonly used small and large mammal models of MI accurately reproduce histopathologically the four characteristic post-MI phases: cardiac cell death, inflammation, myocardial repair and remodelling. However, differences between the time of onset of each characteristic phase and the kinetics of various cellular reactions between human MI and animal models, and between animal models, require careful consideration when defining the variables to be analysed and the timepoints of assessment in experimental studies. Typically, the progression of the different phases post-MI occur more rapidly in rodent models compared with large-animal models and man, suggesting the use of large-animal models is more translational for studying human MI. This review provides an overview of the main anatomopathological features of small and large animal models of MI and discusses the key species-specific histopathological similarities and differences.

Exosomes isolated from the plasma of remote ischemic conditioning rats improved cardiac function and angiogenesis after myocardial infarction through targeting Hsp70.

Remote ischemic conditioning (RIC) is a promising therapeutic strategy to protect heart against ischemic-reperfusion injury. Exosomes have been proved to be an important regulator in many pathological processes. Whether the exosomes derived from RIC could improve cardiac remodeling and function after myocardial infarction (MI) has not been reported. MI animal model was established by ligating the left coronary artery. The bilateral hindlimbs of rats were subjected to RIC treatment using tourniquets. Exosomes were isolated from the plasma of RIC rats and identified by transmission electron microscope. The proliferation, migration, and apoptosis of endothelial cells were measured by CCK8, traswell, and flow cytometry. Western blotting, and qRT-PCR were applied to measure the expression of angiogenesis-related molecules, and immunohistochemistry staining was used to observe the expression of vWF. RIC and RIC exosomes remarkably facilitated cardiac function, cardiac cell remodeling, and angiogenesis. RIC exosomes markedly increased the cell ratio in the G1 phase, cell migration, cell proliferation, tube formation, and inhibited cell apoptosis through Hsp70. The expression of eNOS, iNOS, HIF-1α, Ang-1, and VEGF was markedly increased by RIC exosomes. RIC exosomes significantly improved cardiac function, cardiac remodeling, and angiogenesis after MI, and they accelerated angiogenesis through increasing the levels of angiogenesis-related molecules.

Prospect of Bay Leaf (Syzygium Polyanthum) Extract in Reducing Ischemia and Inflammation in Animal Model of Myocardial Infarction: An Experimental Study

Introduction: Bay leaf (Syzygium polyanthum) was thought to have potential to treat cardiovascular disease traditionally. Myocardial Infarction (MI) characterised by sudden blockage of coronary artery due to atherosclerosis rupture and following MI, several changes could happen such as expression of Hypoxia-Inducible Factor (HIF) 1α, immune cell infiltration, cytokine release, and fibrosis. Aim: To study the effect of bay leaf extract on HIF-1α, immune cell infiltration, IL-10 level, and fibrosis in animal model of MI. Materials and Methods: An Experimental study using animal model of MI was conducted in December 2019. Thirty two Wistar rats were surgically manipulated to have MI. Rats were then divided into two groups: treatment group (with bay leaf extract administration) and control group. Neutrophil and macrophage distribution, collagen (fibrosis) distribution, and HIF-1αexpression were examined in infarcted muscle. Additionally, serum was taken to measure IL-10 level. Observation was conducted on day 1, day 4, day 7, day 14 after MI episode. Independent t-test was used to compare serum IL-10 level between groups. Statistical significance was set at p&lt;0.05. Results: Lower HIF-1α expression was seen in treatment group since day 1, showing better response to ischemia. As for inflammation, decreased neutrophil distribution, increased macrophage distribution was observed in treatment group. Significant increases in IL-10 level were also noticed since day 1 in treatment group (p&lt;0.05 in all observation day). Lower fibrosis was also noticed from day 1 in treatment group. All these effects were further seen in day 4, day 7, and day 14. Conclusion: Bay leaf extract has potential in reducing ischemia, inflammation, and cardiac fibrosis in animal model of MI.

Over-Expression of Inhibitor of Differentiation 2 Attenuates Post-Infarct Cardiac Fibrosis Through Inhibition of TGF-β1/Smad3/HIF-1α/IL-11 Signaling Pathway.

Background: Cardiac fibrosis after myocardial infarction mainly causes cardiac diastolic and systolic dysfunction, which results in fatal arrhythmias or even sudden death. Id2, a transcriptional repressor, has been shown to play an important role in the development of fibrosis in various organs, but its effects on cardiac fibrosis remain unclear. This study aimed to explore the effects of Id2 on cardiac fibrosis after myocardial infarction and its possible mechanisms.Methods: This study was performed in four experimental groups: control group, treatment group (including TGF-β1, hypoxia or MI), treatment+GFP group and treatment+Id2 group. In vitro anoxic and fibrotic models were established by subjecting CFs or NRVMs to a three-gas incubator or TGF-β1, respectively. An animal myocardial infarction model was established by ligating of the left anterior descending coronary artery followed by directly injecting of Id2 adenovirus into the myocardial infarct’s marginal zone.Results: The results showed that Id2 significantly improved cardiac EF and attenuated cardiac hypertrophy. The mRNA and protein levels of α-SMA, Collagen I, Collagen III, MMP2 and TIMP1 were higher in treatment+Id2 group than those in treatment group as well as in treatment+GFP group both in vivo and in vitro. Immunofluorescence revealed that both α-SMA and vimentin were co-expressed in the treatment group and GFP group, but the co-expression were not detected in the control group and Id2 group. Additionally, our findings illustrated that Id2 had protective effects demonstrated by its ability to inhibit the TGF-β1/Smad3/HIF-1α/IL-11 signaling pathways. Besides, over-expression of Id2 reduced cardiomyocytes apoptosis.Conclusion: In conclusion, this study demonstrated that over-expression of Id2 preserved cardiac function and ameliorated adverse cardiac remodeling, which might be a promising treatment target for cardiac fibrosis and apoptosis.

P1215Non-invasive angiogenesis assessment with PET/CT in a rabbit model of myocardial infarction: feasibility and comparison with molecular markers

Abstract Background Translational molecular imaging using Positron Emission Tomography/Computed Tomography (PET/CT) and Transesophageal Echocardiography (TEE) are powerful non-invasive tools for investigation and monitoring of cardiovascular functions. Following myocardial infarction (MI), formation of new blood vessels (angiogenesis) is of importance in the healing process and can be assessed with the PET tracer 68Ga-NODAGA-E[(cRGDyK)]2 (68Ga-RGD). Purpose The purpose of the study was to assess angiogenesis in a rabbit model of myocardial infarction using molecular imaging (PET/CT) and furthermore to validate the findings using TEE, immunohistochemistry (IHC) and quantitative PCR (qPCR). Methods Ten NZW rabbits were used (MI: n=5, SHAM: n=5). Angiogenesis was assessed with 68Ga-RGD before, 1 and 3 weeks after interventions using PET/CT (Inveon System, Siemens Health Care). TEE was used per-operatively and at termination for assessment of the MI (S8–3T probe, iE33 System, Phillips). Following the final scans, hearts were harvested for ex vivo analyses. Short axis slides were stained for collagen deposition and myocardial differentiation (H&amp;E and Masson's trichrome), endothelial cells (CD31), and macrophage infiltration (RAM11). Gene expression alterations related to wound healing response (inflammation, granulation, and tissue remodeling) were measured using qPCR arrays (84 genes analyzed). Results One week after the interventions, 68Ga-RGD uptake, as assessed with PET was increased in the infarct area when compared to the remote zone of the same rabbit as well as compared to the SHAM group. Three weeks after intervention, there was no difference in 68Ga-RGD uptake between groups. High quality TEE images were obtained in all rabbits. Ex vivo analyses at 3 weeks after intervention revealed moderate vessel formation (CD31) in the infarct zone, none in the border zone, whereas surrounding viable myocardium had visible CD31 positive vessels comparable to the SHAM group. Macrophage infiltration (RAM11) and collagenous scaring (Masson's trichrome) was pronounced in the infarcted area. Gene expression alterations in the infarct area (30 of 84 genes upregulated) were dominated by increased expression of collagens (COL1A2, COL5A1, COL5A4), inflammatory chemokines and cytokines (CCL2, IL1A, IL1B, IL6, IL10) and ECM remodeling enzymes (uPAR, TPA, TIMP1, SERPINE1, MMP9) in the MI group compared to the SHAM group, whereas integrins involved in the angiogenesis response (ITGA4, ITGAV) were only moderately changed in the infarction at termination, confirming the in vivo PET findings. Study outline Conclusions In this rabbit MI model, we demonstrate the feasibility of monitoring angiogenesis in the healing process non-invasively with PET. The imaging results were confirmed by IHC and gene expression analysis. Moreover, TEE using a dedicated pediatric probe is feasible in the rabbit model, making this a robust and translational medium-sized animal model of myocardial infarction.

P6309Impaired secretion of clusterin in pericardial fluid of diabetics, a deleterious outcome for the cardiac micro-vasculature

Abstract Background Extracellular vesicles are vital mediators of cell-to-cell communications. We previously demonstrated that in the adult heart, exosomes released in the pericardial fluid (PF) have the functional capability to induce cell survival and angiogenesis in recipient endothelial cells. It has previously been shown that PF exosomes from patients with an existing myocardial infarction (MI) contain clusterin (CLU). Remarkably, secreted CLU is cardio-protective as evidenced by enhanced arteriogenesis and reduced apoptosis in animal models of MI. We hypothesize that type 2 Diabetes Mellitus (T2DM) along with ischemic heart disease (IHD) alters PF EV content impairing its reparative angiogenic potential. Aim To investigate the role of T2DM in modulating human PF exosomal content and its vascular action. Methods and results PF samples were collected from 3 different groups of patients (N=3): 1) Ischemic heart disease (IHD) with or 2) without T2DM, and 3) non-ischaemic, non-diabetic controls operated for mitral valve repair. The impact of PF exosomes on human coronary microvascular ECs (HCMECs) was evaluated by cell based functional assays for measuring apoptosis, proliferation and angiogenesis. Interestingly, unlike PF exosomes from control patients, PF exosomes from DM patients with IHD promoted EC apoptosis and impaired angiogenesis. To investigate the effect of T2DM on PF content, we performed high throughput proteomic and metabolomic analysis of whole PF and PF EVs. We identified proteins and metabolites that were differentially expressed under T2DM condition by using the R package Limma. Employing a network approach, protein and metabolic data were integrated by using our newly developed inhouse R package Metabosignal. This networks approach revealed an interesting interaction circuit involving protein CLU. The T2DM-associated reduction of CLU level in the PF, identified from the “omics” analyses was confirmed by ELISA (n=8 patients per group). To examine the effects of DM and ischemia on CLU intracellular expression and secretion, HCMECs were exposed to high D-glucose (HG, 25 mM) and hypoxia (1%O2). In line with our PF data, HCMECs exposed to HG and hypoxia showed lower levels of both CLU mRNA and secreted CLU (ELISA). Importantly, recombinant CLU (rCLU) treatment on HCMECs rescued their angiogenic potential, induced cell proliferation and protected them from apoptosis under both HG and hypoxia conditions. In addition, silencing of endogenous levels of CLU in HCMECs impaired angiogenesis, suggesting that CLU might be an inherent component of the angiogenesis machinery in ECs. Conclusions This study suggests that DM reduces the level of secreted CLU in the PF, depriving myocardial micro-vessels of this protective and regenerative mediator. Restoring diminished CLU levels in the diabetic heart could be a possible therapeutic approach for contrasting diabetic micro-angiopathy. Acknowledgement/Funding British Heart Foundation Program Grant

Vanillylmandelic acid protects against reperfusion injury in an experimental animal model of myocardial infarction

Vanillylmandelic acid, a catecholamine end-metabolite, has been shown to have several biological properties in previous studies, despite considered biologically inactive. We examined the potential effects of vanillylmandelic acid on the ischemic heart following myocardial infarction and reperfusion on a rat model. Thirty-four female Wistar rats were randomized into two groups, control and experimental. They were anesthetized and subjected to myocardial infarction through left anterior descending artery ligation. A previously studied dose of vanillylmandelic acid (10 mg/kg) was administered and the following parameters were studied during ischemia and reperfusion: a) mortality b) severity of ventricular tachyarrhythmias c) premature ventricular contractions and d) heart rate. Administration of vanillymandelic acid significantly reduced the severity of ventricular tachyarrhythmias and mortality rate during reperfusion, while it did not affect any other of the parameters studied. In conclusion, reperfusion injury was blunted through vanillylmandelic acid administration, which seems to be mediated by parasympathetic activation.

Investigating the expression of miRNA-133 in animal models of myocardial infarction and its effect on cardiac function.

This study aimed to investigate the expression of miR-133 in animal models of myocardial infarction and its effect on cardiac function. Forty-five male-specific pathogen-free (SPF) C57/BL6 mice were selected, among which 35 were made for animal models of myocardial infarction and were enrolled into Model Group and another 10 were enrolled into Blank Control Group. Seven mice died in the model making. Ten mice randomly selected from the 28 mice successfully modeled were transfected with adenovirus carrying miRNA-133 and set as Virus Group, while the remaining 18 mice were randomly divided into Virus No-load Group and Model Group. Mice in Virus Group were transfected with adenovirus carrying miRNA-133, while those in Virus No-load Group were transfected with empty viral vectors without miRNA-133. The left ventricular ejection fraction (LVEF) and fractional shortening (FS) of the mice weeks after the infection were recorded and evaluated by echocardiography. The relative expression levels of miR-133 in the heart tissues of the four groups of mice were compared by Real Time-Polymerase Chain Reaction (RT-PCR). The miR-133 expressions in Blank Control Group and Virus Group were higher than that of Model Group (p<0.05). Then, the myocardial infarction area of mice was compared. The LVEF and FS values of mice in Model Group, Virus No-load Group, and Virus Group were significantly lower than those in Blank Control Group, with the LVEF and FS values of Virus Group higher than that of Model Group and Virus No-load Group (p<0.05). The swimming time of Blank Control Group was significantly higher than that of Model Group and Virus Group (p<0.05), with Virus Group and Virus No-load Group having a greatly longer swimming time than Model Group (p<0.05). The myocardial infarction area of mice in Virus Group was significantly smaller than that in Model Group and Virus No-load Group, the difference was statistically significant (p<0.05). There was no significant difference in myocardial infarction area of mice between Model Group and Virus No-load Group (p>0.05). MiR-133 was in a low expression state in the mice models of myocardial infarction and the overexpression of miR-133 could significantly improve the cardiac function index and motor function, as well as reduce the myocardial infarction area of mice with myocardial infarction. This could inspire new molecular therapy for the treatment of myocardial infarction.

A comprehensive, multiscale framework for evaluation of arrhythmias arising from cell therapy in the whole post-myocardial infarcted heart

Direct remuscularization approaches to cell-based heart repair seek to restore ventricular contractility following myocardial infarction (MI) by introducing new cardiomyocytes (CMs) to replace lost or injured ones. However, despite promising improvements in cardiac function, high incidences of ventricular arrhythmias have been observed in animal models of MI injected with pluripotent stem cell-derived cardiomyocytes (PSC-CMs). The mechanisms of arrhythmogenesis remain unclear. Here, we present a comprehensive framework for computational modeling of direct remuscularization approaches to cell therapy. Our multiscale 3D whole-heart modeling framework integrates realistic representations of cell delivery and transdifferentiation therapy modalities as well as representation of spatial distributions of engrafted cells, enabling simulation of clinical therapy and the prediction of emergent electrophysiological behavior and arrhythmogenensis. We employ this framework to explore how varying parameters of cell delivery and transdifferentiation could result in three mechanisms of arrhythmogenesis: focal ectopy, heart block, and reentry.

Construction of CNA35 Collagen-Targeted Phase-Changeable Nanoagents for Low-Intensity Focused Ultrasound-Triggered Ultrasound Molecular Imaging of Myocardial Fibrosis in Rabbits.

Myocardial fibrosis plays an important role in the development of heart failure and malignant arrhythmia, which potentially increases the incidence of sudden cardiac death. Therefore, early detection of myocardial fibrosis is of great significance for evaluating the prognosis of patients and formulating appropriate treatment strategies. Late gadolinium-enhanced magnetic resonance imaging is considered as the currently effective strategy for noninvasive detection of myocardial fibrosis, but it still suffers from some critical issues. In this work, multifunctional CNA35-labeled perfluoropentane nanoparticles (CNA35-PFP NPs) have been elaborately designed and constructed for molecular imaging of fibrotic myocardium based on ultrasound imaging. These as-constructed CNA35-PFP NPs are intravenously infused into rabbit circulation with an animal model of myocardial infarction. Especially, these targeted CNA35-PFP NPs with nanoscale size could efficiently pass through the endothelial cell gap and adhere to the surface of fibroblasts in the fibrotic myocardium. Importantly, followed by low-intensity focused ultrasound irradiation on the myocardium, these intriguing CNA35-PFP NPs could transform from liquid into gaseous microbubbles, which further significantly enhanced the ultrasound contrast in the fibrotic area, facilitating the detection by diagnostic ultrasound imaging. Therefore, this work provides a desirable noninvasive, economical, and real-time imaging technique for the assessment of cardiac fibrosis with diagnostic ultrasound based on the rational design of liquid-to-gas phase-changeable nanoplatforms.

Stem cell-derived extracellular vesicles for myocardial infarction: a meta-analysis of controlled animal studies.

AimsStem cell-derived extracellular vesicles (EVs) have emerged as a promising therapy for myocardial infarction, but its effects remain incompletely understood. We aim to systematically review the efficacy of EVs on myocardial infarction in both small and large animals.MethodsOn April 5, 2018, we searched the PubMed, Embase and Web of Science databases using variations of “myocardial infarction” and “extracellular vesicle”. Controlled studies about the treatment effects of stem cell-derived EVs in myocardial infarction animal model were included. Meta-regression analysis was used to reveal the factors affecting the EVs treatments.ResultsOf 1210 studies retrieved, 24 were eligible for meta-analysis. EVs injection was associated with the improvements of left ventricular ejection fraction (12.65%), fractional shortening (7.54%) and the reduction of infarct size/area at risk (-15.55%). Meta-regression analysis did not reveal the association between treatment efficacy and type of stem cell, ligation-to-injection interval, route of delivery, dosage of delivery or follow-up period (all P values > 0.05). The median quality score of eligible studies was only 1, indicating potential risks of bias.ConclusionStem cell-derived EVs improve cardiac function and reduce infarct size in myocardial infarction animals, but current pool-up study reveals no associations between common factors and treatment effects.

Ticagrelor Does Not Protect Isolated Rat Hearts, Thus Clouding Its Proposed Cardioprotective Role Through ENT 1 in Heart Tissue.

P2Y12 receptor-blocking drugs given at reperfusion offer protection against myocardial infarction in animal models of transient coronary occlusion. Two recent reports concluded that ticagrelor was more cardioprotective than clopidogrel and attributed this to ticagrelor's unique ability to raise tissue adenosine by blocking the equilibrative nucleoside transporter 1. Indeed, an adenosine receptor blocker attenuated ticagrelor's protection. The related P2Y12 inhibitor cangrelor, which does not block the transporter, protects hearts only when platelets are in the perfusate, while adenosine is known to protect equally in situ blood-perfused and crystalloid-perfused isolated hearts. We, therefore, tested whether ticagrelor liberates a sufficient amount of adenosine to protect a Krebs buffer-perfused isolated rat heart subjected to 40 minutes of global ischemia followed by 2 hours of reperfusion. In untreated hearts, 77.6% ± 4.0% of the ventricle was infarcted as measured by triphenyltetrazolium staining. Ischemically preconditioned hearts had only 32.7% ± 3.6% infarction ( P < .001 vs untreated), indicating that our model could be protected by preconditioning which is known to involve adenosine. Strikingly, hearts treated with 10 μmol/L ticagrelor in the buffer throughout the reperfusion period had 77.5% ± 2.4% infarction comparable to unprotected controls ( P = NS vs untreated). These data strongly suggest that ticagrelor was unable to release sufficient adenosine from the crystalloid-perfused rat heart to protect it against infarction. Our previous studies have found no difference in the anti-infarct potency among clopidogrel, cangrelor, and ticagrelor in open-chest rats and rabbits, and surprisingly adenosine receptor antagonists block protection from all 3 drugs. We have no explanation why ticagrelor is more protective in the pig than clopidogrel but suspect a species or perhaps a treatment schedule difference that may or may not involve adenosine.

Nanomedicine for Gene Delivery for the Treatment of Cardiovascular Diseases.

Background:Myocardial infarction (MI) is the most severe ischemic heart disease and di-rectly leads to heart failure till death. Target molecules have been identified in the event of MI including increasing angiogenesis, promoting cardiomyocyte survival, improving heart function and restraining inflammation and myocyte activation and subsequent fibrosis. All of which are substantial in cardiomy-ocyte protection and preservation of cardiac function.Methodology:To modulate target molecule expression, virus and non-virus-mediated gene transfer have been investigated. Despite successful in animal models of MI, virus-mediated gene transfer is hampered by poor targeting efficiency, low packaging capacity for large DNA sequences, immunogenicity induced by virus and random integration into the human genome.Discussion:Nanoparticles could be synthesized and equipped on purpose for large-scale production. They are relatively small in size and do not incorporate into the genome. They could carry DNA and drug within the same transfer. All of these properties make them an alternative strategy for gene transfer. In the review, we first introduce the pathological progression of MI. After concise discussion on the current status of virus-mediated gene therapy in treating MI, we overview the history and development of nanoparticle-based gene delivery system. We point out the limitations and future perspective in the field of nanoparticle vehicle.Conclusion:Ultimately, we hope that this review could help to better understand how far we are with nanoparticle-facilitated gene transfer strategy and what obstacles we need to solve for utilization of na-nomedicine in the treatment of MI.