Model Of Myocardial Ischemia Research Articles

Erratum: Improved Rodent Model of Myocardial Ischemia and Reperfusion Injury.

An erratum was issued for:Improved Rodent Model of Myocardial Ischemia and Reperfusion Injury. The Authors section wasupdated. The Authors section was updated from: Hua-Qin Tong*1 Man-Lu Fan*1 Tong Sun1 Hao-Wen Zhang2 Jie Han3 Meng-Xi Wang1 Jian-Dong Chen3 Wei-Xin Sun4 Xiao-Hu Chen3 Mian-Hua Wu5 1First College of Clinical Medicine, Biological Technology Center for Innovation in Chinese Medicine, Nanjing University of Chinese Medicine 2School of Health Preservation and Rehabilitation, Key Laboratory of Acupuncture and Medicine Research of Ministry of Education 3Department of Cardiology, Jiangsu Provincial Hospital of Chinese Medicine 4Department of Cardiology, Yancheng TCM Hospital Affiliated to Nanjing University of Chinese Medicine 5Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine * These authors contributed equally to: Hua-Qin Tong*1,2,3 Man-Lu Fan*3 Tong Sun3 Hao-Wen Zhang4 Jie Han5 Meng-Xi Wang3 Jian-Dong Chen5 Wei-Xin Sun6 Xiao-Hu Chen1,2 Mian-Hua Wu7 1Department of Cardiology, Affiliated Hospital of Nanjing University of Chinese Medicine 2Department of Cardiology, Jiangsu Province Hospital of Chinese Medicine 3First College of Clinical Medicine, Biological Technology Center for Innovation in Chinese Medicine, Nanjing University of Chinese Medicine 4School of Health Preservation and Rehabilitation, Key Laboratory of Acupuncture and Medicine Research of Ministry of Education 5Department of Cardiology, Jiangsu Provincial Hospital of Chinese Medicine 6Department of Cardiology, Yancheng TCM Hospital Affiliated to Nanjing University of Chinese Medicine 7Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine * These authors contributed equally.

IL-6 inhibitors effectively reverse post-infarction cardiac injury and ischemic myocardial remodeling via the TGF-β1/Smad3 signaling pathway.

Approximately one in four myocardial infarctions occur in older patients. The majority of therapeutic advances are either not appropriate or not tested in elderly patients. The main reasons for deviating from the guidelines are justified concerns regarding the effectiveness of the recommended forms of therapy, fear of adverse drug reactions and ethical concerns. Targeting interleukin 6 (IL-6) for ventricular remodeling after cardiovascular damage is a feasible alternative to standard polypharmaceutics, but the underlying molecular mechanisms are not well understood. Continuous activation of the IL-6-associated cytokine receptor gp130 leads to cardiomyopathic hypertrophy. TGFβ1 is involved in forming fibrosis in various organs, and its overexpression can cause myocardial hypertrophy and fibrosis. Il-6 has been hypothesized to be indirectly involved in cardiac remodeling via the TGFβ1/Smad signaling transduction pathway. In the present study, a rat model of acute myocardial ischemia, IL-6 and IL-6 receptor blockers were injected directly into the necrotic myocardium. Changes in cardiac function, myocardial infarction area, myocardial collagen, necrotic myocardial fibrosis and levels of TGFβ1, IL-6 and MMP2/9 were quantified in myocardial tissue fibrosis by ELISA. The present study demonstrated that IL-6 stimulated myocardial fibrosis through the TGFβ1-Smad-MM2/9 signaling transduction pathway. Overall, this provided a solid foundation for understanding the relationship between IL-6 and ventricular remodeling.

Integration of metabolomics and transcriptomics to reveal anti-chronic myocardial ischemia mechanism of Gualou Xiebai decoction

Ethnopharmacological relevanceGualou Xiebai decoction (GLXB), a well-known classic traditional Chinese medicine formula, is a recorded and proven therapy for the management of cardiac diseases. However, its pharmacological characteristics and mechanism of action are unclear. Materials and methodsThe effects of GLXB and its mechanism of action in an isoprenaline-induced rat model of chronic myocardial ischemia (CMI) were investigated by incorporating metabonomics and transcriptomics. Meanwhile, the echocardiographic evaluation, histopathological analysis, serum biochemistry assay, TUNEL assay and western blot analysis were detected to revealed the protective effects of GLXB on CMI. ResultsThe results of echocardiographic evaluation, histopathological analysis and serum biochemistry assay revealed that GLXB had a significantly cardioprotective performance by reversing echocardiographic abnormalities, restoring pathological disorders and converting the serum biochemistry perturbations. Further, the omics analysis indicated that many genes and metabolites were regulated after modeling and GLXB administration, and maintained the marked “high-low” or “low-high” trends. Meanwhile, the results from integrated bioinformatics analysis suggested that the interaction network mainly consisted of amino acid and organic acid metabolism. The results of TUNEL assay and western blot analysis complemented the findings of integrated analysis of metabolomics and transcriptomics. ConclusionThese findings suggested that GLXB has a curative effect in isoproterenol-induced CMI in rats. Integrated analysis based on transcriptomics and metabolomics studies revealed that the mechanism of GLXB in alleviating CMI was principally by the regulation of energy homeostasis and apoptosis, which was through a multi-component and multi-target treatment modality.

Curcumin attenuates myocardial ischemia and reperfusion-induced proinflammatory response through activation of the Nrf-2/HO-1 signaling pathway

Acute myocardial infarction (MI) is a global issue with high incidence and mortality. Rapid recovery of the blocked coronary flow represents the most effective strategy to reduce the size of myocardial infarction and improve the cardiac function. The aim of the study is to investigate the effects of curcumin in attenuates myocardial ischemia and reperfusion-induced proinflammatory response through activation of the Nrf-2/HO-1 signaling pathway. Wild‐type C57BL/6J mice (male, 8–10 weeks old) were used and murine myocardial ischemia and reperfusion injury (IRI) model was conducted, cardiac function was evaluated by echocardiography. Infarct size measurement, cardiac troponin-I assays, oxidative stress analysis and histopathological analyzed. The resulted data showed that curcumin alleviates myocardial inflammatory responses and oxidative stress during myocardial IRI. Also, curcumin reduces cell apoptosis induced by myocardial IRI, curcumin reduces cell apoptosis induced by myocardial IRI and activates the Nrf-2/HO-1 signaling pathway during myocardial. Inconclusion, this study demonstrates that curcumin attenuates myocardial IRI by inhibiting proinflammatory cytokines through a mechanism that may be related to activation of the Nrf-2/HO-1 signaling pathway.

Serum Metabolomics Reveals Distinct Profiles during Ischemia and Reperfusion in a Porcine Model of Myocardial Ischemia-Reperfusion.

Acute myocardial infarction (MI) is one of the leading causes of death worldwide. Early identification of ischemia and establishing reperfusion remain cornerstones in the treatment of MI, as mortality and morbidity can be significantly reduced by establishing reperfusion to the affected areas. The aim of the current study was to investigate the metabolomic changes in the serum in a swine model of MI induced by ischemia and reperfusion (I/R) injury, and to identify circulating metabolomic biomarkers for myocardial injury at different phases. Female Yucatan minipigs were subjected to 60 min of ischemia followed by reperfusion, and serum samples were collected at baseline, 60 min of ischemia, 4 h of reperfusion, and 24 h of reperfusion. Circulating metabolites were analyzed using an untargeted metabolomic approach. A bioinformatic approach revealed that serum metabolites show distinct profiles during ischemia and during early and late reperfusion. Some notable changes during ischemia include accumulation of metabolites that indicate impaired mitochondrial function and N-terminally modified amino acids. Changes in branched-chain amino-acid metabolites were noted during early reperfusion, while bile acid pathway derivatives and intermediates predominated in the late reperfusion phases. This indicates a potential for such an approach toward identification of the distinct phases of ischemia and reperfusion in clinical situations.

Impact of timing of morphine treatment on infarct size in experimental animal model of acute myocardial ischemia and reperfusion

Morphine is generally used in clinical treatment for the patients who have not been effectively alleviated for chest pain after the treatment with nitrites or who contraindicate nitrite drugs. However, it was reported that the treatment with morphine in acute myocardial infarction or acute coronary artery syndromes induced increase in myocardial injury even increase of the mortality of the patients. After comparing the reported laboratory studies showing the cardioprotective effects and the clinical observations presenting the harmful consequences, we query whether the timing of the morphine treatment makes the difference in the prognosis of the ischemic/infarct myocardium. We found that intravenous injections of morphine (0.3 mg/kg) at 15 min before the acute myocardial ischemia, at 5 min and 20 min or 60 min after ligation of the coronary artery in separate groups of rats scheduled for acute myocardial ischemia, for 30 min or 90 min followed by reperfusion for 120 min, induced different results, reduction in the size of infarction, no effect and increases of the infarct sizes, respectively. The opioid μ- and kappa-receptors mediated the detrimental effect of morphine on the myocardial injury. The findings of this study suggest that administration of morphine may cause different consequences when used at different time in the pathology of acute myocardial ischemia and reperfusion. The underlying mechanisms in the pathology of acute myocardial ischemia warrant further study.

Investigating the Paracrine Role of Perinatal Derivatives: Human Amniotic Fluid Stem Cell-Extracellular Vesicles Show Promising Transient Potential for Cardiomyocyte Renewal.

Cardiomyocyte renewal represents an unmet clinical need for cardiac regeneration. Stem cell paracrine therapy has attracted increasing attention to resurge rescue mechanisms within the heart. We previously characterized the paracrine effects that human amniotic fluid–derived stem cells (hAFSC) can exert to provide cardioprotection and enhance cardiac repair in preclinical models of myocardial ischemia and cardiotoxicity. Here, we analyze whether hAFSC secretome formulations, namely, hAFSC conditioned medium (hAFSC-CM) over extracellular vesicles (hAFSC-EVs) separated from it, can induce cardiomyocyte renewal. c-KIT+ hAFSC were obtained by leftover samples of II trimester prenatal amniocentesis (fetal hAFSC) and from clinical waste III trimester amniotic fluid during scheduled C-section procedures (perinatal hAFSC). hAFSC were primed under 1% O2 to enrich hAFSC-CM and EVs with cardioactive factors. Neonatal mouse ventricular cardiomyocytes (mNVCM) were isolated from cardiac tissue of R26pFUCCI2 mice with cell cycle fluorescent tagging by mutually exclusive nuclear signal. mNVCM were stimulated by fetal versus perinatal hAFSC-CM and hAFSC-EVs to identify the most promising formulation for in vivo assessment in a R26pFUCCI2 neonatal mouse model of myocardial infarction (MI) via intraperitoneal delivery. While the perinatal hAFSC secretome did not provide any significant cardiogenic effect, fetal hAFSC-EVs significantly sustained mNVCM transition from S to M phase by 2-fold, while triggering cytokinesis by 4.5-fold over vehicle-treated cells. Treated mNVCM showed disorganized expression of cardiac alpha-actinin, suggesting cytoskeletal re-arrangements prior to cell renewal, with a 40% significant downregulation of Cofilin-2 and a positive trend of polymerized F-Actin. Fetal hAFSC-EVs increased cardiomyocyte cell cycle progression by 1.8-fold in the 4-day-old neonatal left ventricle myocardium short term after MI; however, such effect was lost at the later stage. Fetal hAFSC-EVs were enriched with a short isoform of Agrin, a mediator of neonatal heart regeneration acting by YAP-related signaling; yet in vitro application of YAP inhibitor verteporfin partially affected EV paracrine stimulation on mNVCM. EVs secreted by developmentally juvenile fetal hAFSC can support cardiomyocyte renewal to some extension, via intercellular conveyance of candidates possibly involving Agrin in combination with other factors. These perinatal derivative promising cardiogenic effects need further investigation to define their specific mechanism of action and enhance their potential translation into therapeutic opportunity.

Fluorescently Labeled Gadolinium Ferrate/Trigadolinium Pentairon(III) Oxide Nanoparticles: Synthesis, Characterization, In Vivo Biodistribution, and Application for Visualization of Myocardial Ischemia-Reperfusion Injury.

Various gadolinium compounds have been proposed as contrasting agents for magnetic resonance imaging (MRI). In this study, we suggested a new synthesis method of gadolinium ferrate/trigadolinium pentairon(III) oxide nanoparticles (GF/TPO NPs). The specific surface area of gadolinium ferrate (GdFeO3) and trigadolinium pentairon(III) oxide (Gd3Fe5O12) nanoparticles was equal to 42 and 66 m2/g, respectively. The X-ray diffraction analysis confirmed that the synthesized substances were GdFeO3 and Gd3Fe5O12. The gadolinium content in the samples was close to the theoretically calculated value. The free gadolinium content was negligible. Biodistribution of the GF/TPO NPs was studied in rats by fluorescent imaging and Fe2+/Fe3+ quantification demonstrating predominant accumulation in such organs as lung, kidney, and liver. We showed in the in vivo rat model of myocardial ischemia–reperfusion injury that GF/TPO NPs are able to target the area of myocardial infarction as evidenced by the significantly greater level of fluorescence. In perspective, the use of fluorescently labeled GF/TPO NPs in multimodal imaging may provide basis for high-resolution 3D reconstruction of the infarcted heart, thereby serving as unique theranostic platform.

Rhaponticum carthamoides improved energy metabolism and oxidative stress through the SIRT6/Nrf2 pathway to ameliorate myocardial injury

BackgroundRhaponticum carthamoides (Willd.) Iljin (Rha) is a member of the family Compositae that is widely used in folk medicine as a dietary supplement to treat cardiovascular diseases (CVDs), such as senile cardiac insufficiency, and to restore myocardial function after surgery. Sirtuin 6 (SIRT6), an NAD+-dependent class III histone deacetylase, plays a considerable role in the administration of CVDs. However, the specific effects and mechanism of Rha on myocardial injury remain unknown. PurposeThis study aimed to explore the therapeutic potential of Rha against myocardial injury as well as its underlying mechanisms in vivo and in vitro. MethodsA myocardial ischaemia model was established in male SD rats by subcutaneously injecting ISO. The rats were gavaged with Rha (40, 80, 160 mg/kg) or Rho (6 ml/kg) for 14 successive days and then injected subcutaneously with ISO or saline solution on the 13th and 14th days. The positive effects of Rha against myocardial injury in rats were evaluated by ECG assessment, BP measurements, H&E staining, and myocardial enzyme detection. Biochemical indicators of energy metabolism and oxidative stress, such as NAD+/NADH, ATP, and MDA, were analysed by assay kits to assess the effects of Rha. The protein and mRNA expression levels of SIRT6 and Nrf2 in the myocardium were determined by western blotting and real-time PCR. ResultsOur results showed that Rha ameliorated myocardial ischaemia and inhibited energy metabolism disorders (NAD+/NADH ratio, ATP, and LD) and oxidative stress (SOD, ROS, etc.) in rat myocardial tissue and H9c2 cells. In addition, Rha upregulated SIRT6 and Nrf2 expression in myocardial injury. Mechanistic studies then found that SIRT6 knockdown reduced the expression of Nrf2 as well as the effects of Rha on the levels of ATP, LD, and ROS, whereas activation of Nrf2 improved the effects of Rha in cells. In summary, Rha might exert its cardioprotective effects via the SIRT6-mediated Nrf2 signaling pathway. ConclusionThe results suggest that Rha regulates energy metabolism and oxidative stress through the SIRT6/Nrf2 signaling pathway to play a protective role in myocardial injury.

A1 and A2b adenosine receptors regulate GPX4 against ferroptosis of cardiomyocytes in myocardial infarction rat model and in vitro

AimThe regulation of GPX4 by A1AR and A2bAR was investigated, and whether the inhibition of A1AR and A2bAR on ferroptosis of myocardial cell is related to GPX4 was also discussed. Methodswe constructed a rat model of myocardial ischemia and reperfusion (MIR) model and hypoxia/reoxygenation (H/R) model of H9C2 cells, and MIR rats were intraperitoneally injected with A1AR and A2bAR agonists and antagonists. TTC staining, DHE, TUNEL, western blot experiments, immunohistochemistry assay were implemented to analyze the influence of A1AR and A2bAR on ferroptosis and potential role of GPX4. To further authenticate the result of non-specific agonists and antagonists, we transfected siRNA interference or overexpression vectors into cells. CCK8, flow cytometry and western blot were performed to evaluate cell proliferation and apoptosis, and the expression of GPX4 and ferroptosis-related proteins. ResultsThe experimental results showed that reduced expression of A1AR, A2bAR and GPX4 was found after MIR. A1AR and A2bAR activation by agonists increased GPX4 expression and decreased production of lipid ROS, further inhibiting apoptosis of cardiomyocytes. In addition, we also analyzed the effect of A1AR and A2bAR on ferroptosis-related proteins. We found that expression of FIH1 protein increased and expression of ACSL4 and NOX1 proteins decreased. Consistent with results in vivo, cellular data also indicated that A1AR and A2bAR overexpression could increase proliferation ability of H9C2, and inhibit apoptosis and ROS production, upregulate GPX4 and FIH1, and downregulate ACSL4 and NOX1. ConclusionA1AR and A2bAR could regulate GPX4, thereby affecting ferroptosis of cardiomyocytes in a rat model of MIR.

Protective mechanisms of 10-gingerol against myocardial ischemia may involve activation of JAK2/STAT3 pathway and regulation of Ca2+ homeostasis

10-Gingerol (10-Gin), an active ingredient extracted from ginger, has been reported to have beneficial effects on the cardiovascular system. However, its protective effects on myocardial ischemia (MI) and the underlying cellular mechanisms are still unclear. To investigate the protection conferred by 10-Gin against MI injury and its potential mechanisms in cardiomyocytes via patch-clamp and molecular biology techniques. A rat MI model was established using the subcutaneous injection of isoproterenol (85 mg/kg) administered on two consecutive days. 10-Gin was pre-administered to rats for seven days to assess its cardio-protection. The patch-clamp and IonOptix Myocam detection techniques were used to investigated 10-Gin’s effects on L-type Ca2+ channels (LTCCs), Ca2+ transients and cell contractility in isolated rat cardiomyocytes. 10-Gin administration alleviated MI injury, improved cardiac function and myocardial histopathology, reduced myocardial infarct area, downregulated oxidative stress and Ca2+ levels, and decreased the expression of apoptotic factors. Importantly, 10-Gin led to an increase in phosphorylated Janus kinase 2 and signal transducer and activator of transcription 3 (JAK2 and STAT3, respectively) expressions. Furthermore, 10-Gin inhibited LTCCs in a concentration-dependent manner with a half-maximal inhibitory concentration of 75.96 μM. Moreover, 10-Gin administration inhibited Ca2+ transients and cell contractility. Our results suggest that 10-Gin exerts cardioprotective effects on MI in vivo and in vitro in connection with the inhibition of oxidative stress and apoptosis via activation of the JAK2/STAT3 signalling pathway, and regulation of Ca2+ homeostasis by LTCCs.

Muscone Inhibits the Excessive Inflammatory Response in Myocardial Infarction by Targeting TREM-1.

The inhibitory effect of muscone on the hyperinflammatory response after myocardial ischemia reperfusion injury (MIRI) was investigated, and the target and signal pathways of muscone were explored. The levels of inflammatory cytokines interleukin-1β, interleukin-6, and tumor necrosis factor alpha were detected through qRT-PCR and ELISA. The expression levels of p38 and NF-κB signaling pathway-related proteins were detected through Western blot. TREM-1 siRNA was transfected into macrophages in vitro. The rat model of myocardial ischemia was established and used in studying the inhibitory effect of muscone on the inflammatory response and its protective effect muscone on myocardial apoptosis. The expression of TREM-1 was upregulated during myocardial ischemia. Knocking down TREM-1 decreased the increase in inflammatory cytokines in the supernatant of macrophages induced by rmHMGB1 (1 μg/mL) and rmHSP60 (1 mol/mL). In addition, knocking down TREM-1 decreased p38 and NF-κB signaling activation. Muscone can protect myocardial cells by inhibiting the expression of TREM-1 and the inflammatory response after myocardial infarction. Further study showed that muscone inhibited the production of DAM-triggered (damage-associated molecular pattern trigger) inflammatory cytokines. In addition, muscone inhibited the activation of p38 and NF-κB signals under DAM-induced conditions. Muscone and TREM-1 gene knockout reduced cell apoptosis and provided protection against MIRI by inhibiting p38 and NF-κB signaling activation. Mechanism studies showed that muscone inhibited the production and release of inflammatory cytokines by inhibiting TREM-1, and thereby reducing the inflammatory response and providing protection against MIRI.

Targeted neutrophil-mimetic liposomes promote cardiac repair by adsorbing proinflammatory cytokines and regulating the immune microenvironment

Acute myocardial infarction (MI) induces a sterile inflammatory response that may result in poor cardiac remodeling and dysfunction. Despite the progress in anti-cytokine biologics, anti-inflammation therapy of MI remains unsatisfactory, due largely to the lack of targeting and the complexity of cytokine interactions. Based on the nature of inflammatory chemotaxis and the cytokine-binding properties of neutrophils, we fabricated biomimetic nanoparticles for targeted and broad-spectrum anti-inflammation therapy of MI. By fusing neutrophil membranes with conventional liposomes, we fabricated biomimetic liposomes (Neu-LPs) that inherited the surface antigens of the source cells, making them ideal decoys of neutrophil-targeted biological molecules. Based on their abundant chemokine and cytokine membrane receptors, Neu-LPs targeted infarcted hearts, neutralized proinflammatory cytokines, and thus suppressed intense inflammation and regulated the immune microenvironment. Consequently, Neu-LPs showed significant therapeutic efficacy by providing cardiac protection and promoting angiogenesis in a mouse model of myocardial ischemia–reperfusion. Therefore, Neu-LPs have high clinical translation potential and could be developed as an anti-inflammatory agent to remove broad-spectrum inflammatory cytokines during MI and other neutrophil-involved diseases.Graphical

Association between Blood Copper Levels and the Incidence of Ischemic Heart Disease

Background: Ischemic heart disease is one of the interrelated disease amongst cardiovascular disease group. Pathophysiological model of ischemic heart disease and myocardial ischemia are caused by obstructive atherosclerotic plaque, which involves the narrowing of small blood vessels that oxygenate the heart muscle by the build-up of plaque. Diet plays an important role in ischemic heart disease. Copper, an essential trace metal micronutrient, is required for myocardial angiogenesis action. Copper deficiency leads to cardiac mitochondrial structural defect and interference in oxidative phosphorylation.
 Aims: This study aims to examine the association between blood copper levels amd the incidence of ischemic heart disease.
 Methods: A total of 30 patients in cardiovascular clinic in Universitas Sumatera Utara Hospital in Medan, Indonesia from September 2021 until January 2022 were included in this cross-sectional study, with descriptive analytics. Demographic data, smoking behavior, supplement consumption, anthropometry measurements, body mass index, medical history were collected. Food frequency questionnaire (semiquantitative FFQ) was used to obtain food recall data. Blood level of copper were analysed in Prodia Clinical Laboratory.
 Results: Out of 30 patients in this study, 70% were male with a mean age of 60.6 years old. Research subjects who had risk factor of smoking were as much as 33.3%. Comorbidities such as dyslipidemia and diabetes mellitus were apparent, which were 63.3% and 30%, respectively. Sixty percent of the subjects were sedentary with mean body mass index 25.9 kg/m2. Median level of copper consumed daily was 1400 mcg/day and mean blood copper level was 1034,5 mg/L. Based on the blood copper level analysis of the subjects, we found an insignificant negative correlation between blood copper level with the incidence of ischemic heart disease (r = -0.050; p <0.795).
 Conclusion: This study found no association between blood copper levels and the incidence of ischemic heart disease.

Therapeutic application of chick early amniotic fluid: effective rescue of acute myocardial ischemic injury by intravenous administration

Myocardial regeneration has been considered a promising option for the treatment of adult myocardial injuries. Previously, a chick early amniotic fluid (ceAF) preparation was shown to contain growth-related factors that promoted embryonic growth and cellular proliferation, though the nature of the components within ceAF were not fully defined. Here we tested whether this ceAF preparation is similarly effective in the promotion of myocardial regeneration, which could provide an alternative therapeutic for intervening myocardial injury. In this study, a myocardial ischemic injury model was established in adult mice and pigs by multiple research entities, and we were able to show that ceAF can efficiently rescue damaged cardiac tissues and markedly improve cardiac function in both experimental models through intravenous administration. ceAF administration increased cell proliferation and improved angiogenesis, likely via down-regulation of Hippo-YAP signaling. Our data suggest that ceAF administration can effectively rescue ischemic heart injury, providing the key functional information for the further development of ceAF for use in attenuating myocardial injury.

Referred Somatic Hyperalgesia Mediates Cardiac Regulation by the Activation of Sympathetic Nerves in a Rat Model of Myocardial Ischemia.

Myocardial ischemia (MI) causes somatic referred pain and sympathetic hyperactivity, and the role of sensory inputs from referred areas in cardiac function and sympathetic hyperactivity remain unclear. Here, in a rat model, we showed that MI not only led to referred mechanical hypersensitivity on the forelimbs and upper back, but also elicited sympathetic sprouting in the skin of the referred area and C8-T6 dorsal root ganglia, and increased cardiac sympathetic tone, indicating sympathetic-sensory coupling. Moreover, intensifying referred hyperalgesic inputs with noxious mechanical, thermal, and electro-stimulation (ES) of the forearm augmented sympathetic hyperactivity and regulated cardiac function, whereas deafferentation of the left brachial plexus diminished sympathoexcitation. Intradermal injection of the α2 adrenoceptor (α2AR) antagonist yohimbine and agonist dexmedetomidine in the forearm attenuated the cardiac adjustment by ES. Overall, these findings suggest that sensory inputs from the referred pain area contribute to cardiac functional adjustment via peripheral α2AR-mediated sympathetic-sensory coupling.

Synthetic Analogs of 6-Bromohypaphorine, a Natural Agonist of Nicotinic Acetylcholine Receptors, Reduce Cardiac Reperfusion Injury in a Rat Model of Myocardial Ischemia

The data available to date indicate that the activation of nicotinic acetylcholine receptors (nAChR) of α7 type can reduce heart damage resulting from ischemia and subsequent reperfusion. We have studied two new synthetic D-analogs of 6-bromohypaphorine, which are selective agonists of α7 nAChR, in a rat model of myocardial ischemia. Acute myocardial infarction in animals was induced by occlusion of the left coronary artery with its subsequent reperfusion under mechanical lung ventilation. It was found that one of the analogs was more active, and treatment with it at the onset of reperfusion statistically reduced infarct size. This analog also prevented changes in the concentration of potassium and sodium ions in the blood, occurring during occlusion/reperfusion injury. The data obtained indicate that hypaphorine analogs are promising for the development of drugs that reduce the adverse effects of myocardial infarction.

Proteomic study of Tianxiangdan intervention in rats with myocardial ischemia.

The present study aimed to screen out the proteins with significantly differential expression through the proteomics study of Tianxiangdan intervention in rats with myocardial ischemia as well as elucidate the mechanism of the intervention. In total, 54 Wistar rats (male, 6-8 weeks old) were randomly divided into the blank group, sham operation group, and model group, with 6 rats in each, together with the model + low dose group, model + medium-dose group, and model + high dose group, with 12 rats in each. Upon successful construction of the ischemic model, low, medium, and high doses, respectively, of Tianxiangdan were administered in the groups. The rat model of coronary heart disease (CHD) with myocardial ischemia was prepared by ligating the coronary artery. The tandem mass tag-labeled quantitative proteomics technology was adopted to observe the differentially expressed proteins in the myocardium of the model rats under the action of Tianxiangdan to find the target proteins for the treatment of myocardial ischemia in CHD. A total of 3122 proteins were identified. Combined with the references, tropomyosin alpha-3 chain (TPM3), protein kinase C delta (PRKCD), myosin heavy chain 10 (MYH10), MYH6, G protein subunit alpha i2 (GNAI2), and other proteins were screened out. Western blotting was adopted for the proteomics validation, and it was found that compared with the sham operation group, the expression levels of the GNAI2, TPM3, and MYH10 proteins were upregulated in the myocardial ischemia model group but downregulated after the administration of Tianxiangdan; the differences were statistically significant (p<0.05). We conclude that Tianxiangdan could improve myocardial ischemia by downregulating the proteins, including GNAI2, TPM3, and MYH10, which might be potential targets of Tianxiangdan in the treatment of myocardial infarction.

Modulation effects of danshen-honghua herb pair on gut microbiota of acute myocardial ischemia model rat.

In the recent years, a growing number of studies have shown that the occurrence of myocardial ischemia (MI) is closely related to the gut microbiota (GM). The Danshen-Honghua herb pair (DHHP), a classic combination in traditional Chinese herbal formulas, has been widely applied throughout history to cure cardiovascular disease, exhibiting remarkable clinical efficacy to treat ischemic heart disease (IHD). However, the intrinsic regulation mechanism of DHHP in treating MI remains unclear. This study aims to investigate the possible protective mechanism of DHHP in rats with acute myocardial ischemia (AMI) induced by isoproterenol (ISO) through 16S rRNA gene sequencing technique. Pharmacodynamic results showed that DHHP significantly ameliorated the pathological changes and improved the abnormal cardiac enzymes levels in the AMI rats. In addition, GM analysis demonstrated that DHHP effectively ameliorated the ISO-induced dysbiosis of the GM community, mainly by enhancing the GM diversity and increasing the relative abundance of Bacteroides, Roseburia, unclassified_f__Lachnospiraceae, and Lachnospiraceae_NK4A136_group, the abundance ratio of Bacteroidetes to Firmicutes, and decreasing the relative abundance of Escherichia-Shigella and Enterococcus. In summary, this study revealed that DHHP could improve ischemic myocardial injury in rats, and that its regulation mechanism is associated with significantly ameliorating the composition of GM, thus contributing to further our understanding of the anti-MI mechanisms of DHHP.

Transplantation of MITO cells, mitochondria activated cardiac progenitor cells, to the ischemic myocardium of mouse enhances the therapeutic effect

Given the potential for myocardial stem cell transplantation as a promising treatment for heart failure, numerous clinical trials have been conducted and its usefulness has been clearly confirmed. However, the low rate of engraftment of transplanted cells has become a clinical problem, and this needs to be improved in the case of transplanting cells to the heart. To address this issue, we report on attempts to prepare mitochondria-activated stem cells (MITO cells) for use in transplantation. MITO cells, which is cardiac progenitor cells (CPCs) activated by the mitochondrial delivery of resveratrol with an anti-oxidant and mitochondrial activation effects were successfully prepared using a mitochondrial targeting nanocarrier (MITO-Porter). The purpose of this study was to validate the therapeutic effect of cell transplantation by the MITO cells using a mouse model of myocardial ischemia–reperfusion. Mouse CPCs were used as transplanted cells. The transplantation of CPCs and MITO cells were conducted after myocardial ischemia–reperfusion, and the therapeutic effect was determined. The MITO cells transplanted group showed increase in postoperative weight gain, improve cardiac function and inhibition of fibrosis compared to the non-transplanted group and the CPC group. The transplantation of MITO cells to the ischemic myocardium showed a stronger transplantation effect compared to conventional CPC transplantation.