Reperfusion strategies in acute coronary syndromes

Treatment seeking experiences of ACS patients in Yogyakarta, Indonesia during COVID-19 pandemic: A qualitative study

Delay in treatment seeking is recognized as a major contributor for Acute Coronary Syndrome (ACS) mortality in Indonesia. Despite the significance of timely treatment, decline in admission and delay in presentation of patients with ACS were consistently reported during the COVID-19 pandemic. These suggested that treatment seeking performance of patients during the pandemic might be different from the previous period. This qualitative study aimed to explore treatment seeking behaviour, barriers in seeking medical treatment, and experiences of patients with ACS in Yogyakarta, Indonesia during COVID-19 pandemic. In depth-interviews were carried out with 30 patients, who were hospitalized with ACS at one of the three selected hospitals in Yogyakarta during the pandemic period. Thematic analysis was performed to create vital explanations for treatment seeking practices of patients with ACS during pandemic. Three significant themes were identified: treatment seeking decisions, barriers in seeking medical treatment during COVID-19, and experiencing both good and bad impression from entering and staying in the hospital. The intensity of ACS symptoms and fear of COVID-19 infection dominated the delay in seeking medical treatment. Strict safety measures, religious belief, and fear of ACS helped patients overcome barriers and seek medical treatment during pandemic. ACS patients also had convenient medical care during the pandemic and believed medical staff would provide excellent care to them. However, visit restriction policy could cause psychological discomfort. Increase awareness of ACS symptoms and the risk of delays ACS treatment are essential to support patients' decisions to seek medical helps in a timely manner at any situations including pandemic. Interventions aim at alleviating psychological distress should also be designed and implemented to improve treatment experiences of ACS patients, who sought medical treatment during the pandemic crisis.

Gender disparities in the mediating role of symptom knowledge level in reducing acute coronary syndrome (ACS) decision delay: Findings from a community-based study in China

BACKGROUND

Implementing training programs to educate patients on the prodromal symptoms of acute coronary syndrome (ACS) may assist patients in accurately recognizing these symptoms, and ultimately decrease their time delay in seeking emergency medical services (EMS). However, the effectiveness of this approach remains uncertain, particularly among the Chinese population.

METHODS

A cross-sectional study was conducted within 22 communities in Beijing, China between 2015 and 2018, with a total of 1099 participants recruited. The study utilized a standardized questionnaire to evaluate the presence of intentional decision delay in turning to EMS under a hypothetical chest pain, the participants' knowledge of ACS prodromal symptoms, and whether they had ever received any training programs aimed at increasing their symptom knowledge. Mediation analysis was performed with regression models and bootstrapping methods, and gender difference was further analyzed through moderated mediation analysis.

RESULTS

A total of 1099 participants (58.2% female, median [IQR] age 34 [20]) were included in the study. The results of the mediation analysis indicated that training programs were associated with a decrease risk in decision delay, with increased knowledge playing a mediating role (mediation effect/total effect = 36.59%, P < 0.0001). Gender modified this mediation effect, with it being observed only in the male group. Specifically, training programs were not found to significantly decrease decision delay among females (P > 0.05), even though they did improve women's knowledge of ACS prodromal symptoms (β = 0.57, P = 0.012).

CONCLUSION

The results suggested a relationship between prior training programs and reduced decision delay, with increased knowledge of prodromal symptoms of ACS serving as a mediator. However, the effect was only observed in male participants and not in female participants. This highlights the notion that mere transfer of knowledge regarding ACS prodromal symptoms may not be sufficient to mitigate decision delay in the female population. Further research is needed to corroborate these results and to gain deeper insights into the gender-specific barriers encountered in this study.

Time-based reperfusion in haemodynamically unstable pulmonary embolism patients: does early reperfusion therapy improve survival?

High-risk pulmonary embolism (PE) is associated with significant morbidity and mortality. Systemic thrombolysis remains the most evidenced-based treatment for haemodynamically unstable PE, but in daily clinical practice, it remains largely underused. In addition, unlike acute myocardial infarction or stroke, a clear time window for reperfusion therapy, including fibrinolysis, for high-risk PE has not been defined either for fibrinolysis or for the more recently incorporated options of catheter-based thrombolysis or thrombectomy. The aim of the present article is to review the current evidence supporting the potential benefit of earlier administration of reperfusion in haemodynamically unstable PE patients and suggest some potential strategies to further explore this issue.

Prescription patterns of P2Y12 inhibitors following revascularization in the United States: 2013-2018

P2Y12 inhibitors (i.e., clopidogrel, prasugrel, or ticagrelor) are effective at reducing adverse cardiovascular outcomes post-revascularization in coronary artery disease (CAD). However, the choice of a specific P2Y12 inhibitor may vary according to the patient's characteristics, and trends in the use of different P2Y12 inhibitors are not well studied in real-world settings. The objective of this study is to determine trends in the prescription patterns of P2Y12 inhibitors in patients with CAD. We studied 137,073 patients with CAD cross-sectionally using the IBM MarketScan database (2013-2018). Patients with CAD prescribed P2Y12 inhibitors within 14 days of index revascularization were included to compare the utilization of P2Y12 inhibitors based on age and clinical characteristics. There were differences in prescription patterns by age. Among patients aged less than or equal to 65 years (N = 92,734), a continuously increased utilization of ticagrelor was observed from 13.7% to 45.6% replacing clopidogrel as the most prescribed medication by 2018. Similarly, ticagrelor was the choice of drug among patients undergoing percutaneous coronary intervention. Among the patients at high bleeding risk, clopidogrel remained the most prescribed medication with use in 50.6% of patients in 2018 in patients aged less than or equal to 65 years. Contrarily, among the older adults with age 65 or above (N = 44,339), although ticagrelor use increased with time, clopidogrel remained the most utilized drug and was used by 66.2% of patients in 2018. Additionally, clopidogrel was the preferred medication among patients with stroke history. With the increasing use of ticagrelor in real-world practice, further research is needed to observe its impact on cardiovascular outcomes.

Short-term toll-like receptor 9 inhibition leads to left ventricular wall thinning after myocardial infarction

AIMS

Ischaemia-reperfusion injury (IRI) following myocardial infarction remains a challenging topic in acute cardiac care and consecutively arising heart failure represents a severe long-term consequence. The extent of neutrophil infiltration and neutrophil-mediated cellular damage are thought to be aggravating factors enhancing primary tissue injury. Toll-like receptor 9 was found to be involved in neutrophil activation as well as chemotaxis and may represent a target in modulating IRI, aspects we aimed to illuminate by pharmacological inhibition of the receptor.

METHODS AND RESULTS

Forty-nine male adult Sprague-Dawley rats were used. IRI was induced by occlusion of the left coronary artery and subsequent snare removal after 30 min. Oligonucleotide (ODN) 2088, a toll-like receptor 9 (TLR9) antagonist, control-ODN, or DNase, were administered at the time of reperfusion and over 24 h via a mini-osmotic pump. The hearts were harvested 24 h or 4 weeks after left coronary artery occlusion and immunohistochemical staining was performed. Echocardiography was done after 1 and 4 weeks to determine ventricular function. Inhibition of TLR9 by ODN 2088 led to left ventricular wall thinning (P = 0.003) in association with drastically enhanced neutrophil infiltration (P = 0.005) and increased markers of tissue damage. Additionally, an up-regulation of the chemotactic receptor CXCR2 (P = 0.046) was found after TLR9 inhibition. No such effects were observed in control-ODN or DNase-treated animals. We did not observe changes in monocyte content or subset distribution, hinting towards neutrophils as the primary mediators of the exerted tissue injury.

CONCLUSIONS

Our data indicate a TLR9-dependent, negative regulation of neutrophil infiltration. Blockage of TLR9 appears to prevent the down-regulation of CXCR2, followed by an uncontrolled migration of neutrophils towards the area of infarction and the exertion of disproportional tissue injury resulting in potential aneurysm formation. In comparison with previous studies conducted in TLR^-/- mice, we deliberately chose a transient pharmacological inhibition of TLR9 to highlight effects occurring in the first 24 h following IRI.

Liensinine prevents ischemic injury following myocardial infarction via inhibition of Wnt/β‑catenin signaling activation

BACKGROUND

Myocardial infarction (MI) is the leading cause of deaths worldwide, triggering widespread and irreversible damage to the heart. Currently, there are no drugs that can reverse ischemic damage to the myocardium and hence, finding novel therapeutic agents that can limit the extent of myocardial damage following MI is crucial. Liensinine (LSN) is a naturally derived bisbenzylisoquinoline alkaloid that is known to exhibit numerous antioxidative and cardiovascular beneficial effects. However, the role of LSN in MI-induced injury and its underlying mechanisms remain unexplored.

PURPOSE

Our study aims to evaluate the cardioprotective effects of LSN following MI and its underlying molecular mechanisms.

METHODS

We constructed murine models of MI in order to examine the potential cardioprotective effects and mechanisms of LSN in protecting against myocardial ischemic damage both in vivo and in vitro.

RESULTS

Administration with LSN strongly protected against cardiac injuries following MI by decreasing the extent of ischemic damage and improving cardiac function. Additionally, LSN was found to be a potent inhibitor of Wnt/β‑catenin signaling pathway. Hence, the beneficial effects of LSN in preventing oxidative and DNA damage following ischemia was due to its ability to inhibit aberrant activation of Wnt/β‑catenin signaling.

CONCLUSIONS

Our findings reveal for the first time a novel cardioprotective role of LSN during myocardial infarction and most notably, its ability to protect cardiomyocytes against oxidative stress-induced damage via inhibiting Wnt/β-catenin signaling. Our study therefore suggests new therapeutic potential of LSN or plants that contain the natural alkaloid LSN in ischemic heart diseases.

Macrophages in cardiac remodelling after myocardial infarction

Myocardial infarction (MI), as a result of thrombosis or vascular occlusion, is the most prevalent cause of morbidity and mortality among all cardiovascular diseases. The devastating consequences of MI are compounded by the complexities of cellular functions involved in the initiation and resolution of early-onset inflammation and the longer-term effects related to scar formation. The resultant tissue damage can occur as early as 1 h after MI and activates inflammatory signalling pathways to elicit an immune response. Macrophages are one of the most active cell types during all stages after MI, including the cardioprotective, inflammatory and tissue repair phases. In this Review, we describe the phenotypes of cardiac macrophage involved in MI and their cardioprotective functions. A specific subset of macrophages called resident cardiac macrophages (RCMs) are derived from yolk sac progenitor cells and are maintained as a self-renewing population, although their numbers decrease with age. We explore sophisticated sequencing techniques that demonstrate the cardioprotective properties of this cardiac macrophage phenotype. Furthermore, we discuss the interactions between cardiac macrophages and other important cell types involved in the pathology and resolution of inflammation after MI. We summarize new and promising therapeutic approaches that target macrophage-mediated inflammation and the cardioprotective properties of RCMs after MI. Finally, we discuss future directions for the study of RCMs in MI and cardiovascular health in general.

Scalable Generation of Nanovesicles from Human-Induced Pluripotent Stem Cells for Cardiac Repair

Extracellular vesicles (EVs) from stem cells have shown significant therapeutic potential to repair injured cardiac tissues and regulate pathological fibrosis. However, scalable generation of stem cells and derived EVs for clinical utility remains a huge technical challenge. Here, we report a rapid size-based extrusion strategy to generate EV-like membranous nanovesicles (NVs) from easily sourced human iPSCs in large quantities (yield 900× natural EVs). NVs isolated using density-gradient separation (buoyant density 1.13 g/mL) are spherical in shape and morphologically intact and readily internalised by human cardiomyocytes, primary cardiac fibroblasts, and endothelial cells. NVs captured the dynamic proteome of parental cells and include pluripotency markers (LIN28A, OCT4) and regulators of cardiac repair processes, including tissue repair (GJA1, HSP20/27/70, HMGB1), wound healing (FLNA, MYH9, ACTC1, ILK), stress response/translation initiation (eIF2S1/S2/S3/B4), hypoxia response (HMOX2, HSP90, GNB1), and extracellular matrix organization (ITGA6, MFGE8, ITGB1). Functionally, NVs significantly promoted tubule formation of endothelial cells (angiogenesis) (p < 0.05) and survival of cardiomyocytes exposed to low oxygen conditions (hypoxia) (p < 0.0001), as well as attenuated TGF-β mediated activation of cardiac fibroblasts (p < 0.0001). Quantitative proteome profiling of target cell proteome following NV treatments revealed upregulation of angiogenic proteins (MFGE8, MYH10, VDAC2) in endothelial cells and pro-survival proteins (CNN2, THBS1, IGF2R) in cardiomyocytes. In contrast, NVs attenuated TGF-β-driven extracellular matrix remodelling capacity in cardiac fibroblasts (ACTN1, COL1A1/2/4A2/12A1, ITGA1/11, THBS1). This study presents a scalable approach to generating functional NVs for cardiac repair.

CXCR1 and its downstream NF-κB inflammation signaling pathway as a key target of Guanxinning injection for myocardial ischemia/reperfusion injury

Guanxinning Injection (GXNI) is used clinically to treat cardiac injury, but its active components and mode of action remains unclear. Therefore, a myocardial ischemia/reperfusion injury (MIRI) model-based integrated strategy including function evaluation, RNA-seq analysis, molecular docking, and cellular thermal shift assay (CETSA) was employed to elucidate the effect and mechanism of GXNI and its main ingredient on cardiac injury. These results revealed that GXNI significantly improved cardiac dysfunction and myocardial injury in I/R mice. RNA-seq analysis clarified that CXCR1-mediated interleukin-8 pathway played a critical role in MIRI. Molecular docking screening identified danshensu (DSS) as the major active components of GXNI targeting CXCR1 protein, which was confirmed in an oxygen-glucose deprivation/reoxygenation-induced cardiomyocytes damage model showing that GXNI and DSS reduced the protein expression of CXCR1 and its downstream NF-κB, COX-2, ICAM-1 and VCAM-1. CETSA and isothermal dose-response fingerprint curves confirmed that DSS combined with CXCR1 in a dose-dependent manner. Furthermore, GXNI and DSS significantly decreased the expression levels of IL-6, IL-1β and TNF-α and the number of neutrophils in post I/R myocardial tissue. In conclusion, this study revealed that GXNI and its active components DSS exert inhibitory effects on inflammatory factor release and leukocyte infiltration to improve I/R-induced myocardial injury by down-regulating CXCR1-NF-κB-COX-2/ICAM-1/VCAM-1 pathway.

Dexmedetomidine Mitigates Myocardial Ischemia/Reperfusion-Induced Mitochondrial Apoptosis through Targeting lncRNA HCP5

Our study aimed to explore the function and mechanism of Dexmedetomidine (Dex) in regulating myocardial ischemia/reperfusion (I/R)-induced mitochondrial apoptosis through lncRNA HCP5. We demonstrated Dex suppressed I/R-induced myocardial infarction and mitochondrial apoptosis in vivo. Dex induced the expression of lncRNA HCP5 and MCL1, inhibited miR-29a expression and activated the JAK2/STAT3 signaling. Dex attenuated hypoxia/reoxygenation (H/R)-induced mitochondrial apoptosis by upregulating lncRNA HCP5 in cardiomyocytes. Overexpression of lncRNA HCP5 sponged miR-29a to suppress H/R-induced mitochondrial apoptosis. Knockdown of miR-29a also alleviated cardiomyocyte apoptosis by upregulating MCL1. Overexpression of lncRNA HCP5 activated the JAK2/STAT3 signaling through sponging miR-29a and enhancing MCL1 expression in cardiomyocytes. Dex mitigated myocardial I/R-induced mitochondrial apoptosis through the lncRNA HCP5/miR-29a/MCL1 axis and activation of the JAK2/STAT3 signaling.

Health Inequalities of STEMI Care Before Implementation of a New Regional Network: A Prefecture-Level Analysis of Social Determinants of Healthcare in Yunnan, China

BACKGROUND

As one of the most serious types of coronary heart disease, ST-elevation myocardial infarction (STEMI) faces huge challenges in the equal management and care of patients due to its life-threatening and time-critical condition. Health inequalities such as sex and age differences in STEMI care have been reported from developed countries. However, limited outcomes have been investigated and the major drivers of inequality are still unclear, especially in under-developed areas. This study aimed to explore the major drivers of health inequalities in STEMI care before implementation of a new regional network in the south-west of China.

METHODS

Prefecture-level data of STEMI patients before the implementation of a regional network were analysed retrospectively. Drivers of inequality were identified from six social determinants of health, namely area of residence, ethnicity, sex, age, education and occupation. Outcomes of STEMI care included timely presentation, reperfusion therapy, timely reperfusion therapy, heart failure, inpatient mortality, length of hospital stay, hospital costs, and various intervals of ischaemic time.

RESULTS

A total of 376 STEMI patients in the research area before implementation of the STEMI network were included. Compared with urban residents, rural patients were significantly less likely to have timely presentation (odds ratio [OR]=0.47, 95% CI: 0.28-0.80, P=.004) and timely reperfusion therapy (OR=0.32, 95% CI: 0.14-0.70, P=.005). Rural residents were less likely to present to hospital promptly than urban residents (HR=0.65, 95% CI=0.52-0.82, P<.001). In the first 3 hours of percutaneous coronary intervention (PCI) reperfusion delay and first 6 hours of total ischaemic time, rural patients had a significantly lower probability to receive prompt PCI (hazard ratio [HR]=0.40, 95% CI: 0.29-0.54, P<.001) and reperfusion therapy (HR=0.37, 95% CI: 0.25-0.56, P<.001) compared to urban patients.

CONCLUSION

Rural residents were a major vulnerable group before implementation of the regional STEMI network. No obvious inequalities in ethnicity, sex, age, education or occupation existed in STEMI care in Chuxiong Prefecture of China.

Potential therapeutic strategies for myocardial infarction: the role of Toll-like receptors

Myocardial infarction (MI) is a life-threatening condition among patients with cardiovascular diseases. MI increases the risk of stroke and heart failure and is a leading cause of morbidity and mortality worldwide. Several genetic and epigenetic factors contribute to the development of MI, suggesting that further understanding of the pathomechanism of MI might help in the early management and treatment of this disease. Toll-like receptors (TLRs) are well-known members of the pattern recognition receptor (PRR) family and contribute to both adaptive and innate immunity. Collectively, studies suggest that TLRs have a cardioprotective effect. However, prolonged TLR activation in the response to signals generated by damage-associated molecular patterns (DAMPs) results in the release of inflammatory cytokines and contributes to the development and exacerbation of myocardial inflammation, MI, ischemia-reperfusion injury, myocarditis, and heart failure. The objective of this review is to discuss and summarize the association of TLRs with MI, highlighting their therapeutic potential for the development of advanced TLR-targeted therapies for MI.

Transcription factor JDP2 activates PDE4B to participate in hypoxia/reoxygenation‑induced H9c2 cell injury

Myocardial ischemia/reperfusion (I/R) injury is a clinical challenge in the treatment of acute myocardial infarction (AMI). Phosphodiesterase 4B (PDE4B) expression is upregulated in AMI tissues. Thus, the present study aimed to investigate the role of PDE4B in myocardial I/R injury. H9c2 cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) to establish an in vitro myocardial I/R model. PDE4B expression was detected via reverse transcription-quantitative PCR (RT-qPCR) and western blotting before and after transfection with PDE4B interference plasmids in H/R-stimulated H9c2 cells. Cell viability and cytotoxicity were assessed using the Cell Counting Kit-8 and lactate dehydrogenase assays, respectively. Furthermore, oxidative stress was assessed using malondialdehyde, superoxide dismutase and glutathione/glutathione oxidized ratio detection kits. Cell apoptosis was detected via a TUNEL assay and western blotting. c-Jun dimerization protein 2 (JDP2) expression was also detected via RT-qPCR and western blotting. The dual luciferase reporter and chromatin immunoprecipitation assays were performed to verify the interaction between JDP2 and PDE4B. Following co-transfection with PDE4B interference plasmid and JDP2 overexpression plasmid, cell viability, cytotoxicity, oxidative stress and cell apoptosis were assessed. The results demonstrated that PDE4B knockdown reversed H/R-induced loss of viability and cytotoxicity of H9c2 cells. H/R-induced oxidative stress and cardiomyocyte apoptosis were also alleviated by PDE4B knockdown. In addition, the transcription factor JDP2 was expressed at high levels in H/R-stimulated H9c2 cells, and JDP2 overexpression upregulated PDE4B expression. Notably, JDP2 overexpression partly reversed the ameliorative effect of PDE4B knockdown on H/R-induced H9c2 injury. Taken together, the results of the present study suggested that JDP2-activated PDE4B contributed to H/R-induced H9c2 cell injury.

Evaluation of a cardiac troponin process flow at the chest pain center with the shortest turnaround time

BACKGROUND

Early diagnosis of myocardial infarction is crucial in chest pain management and cardiac troponin (cTn) test is an important step in it. Process improvement to shorten the test turnaround time (TAT) may improve patients' outcomes. The cTn test at chest pain center (CPC) of Zhongshan Hospital had the shortest TAT ever reported, but its process flow was not fully evaluated.

METHODS

We performed a stepwise evaluation of CPC cTn TAT and explored the potential factor that might cause delay. The performance of CPC cTn test was also compared with cTn test and human chorionic gonadotropin (HCG) test ordered from emergency department (ED).

RESULTS

At least 95% of CPC cTn tests were completed in 60 min, while 62% in 30 min. The medians of monthly order-to-collect time, collect-to-received time, and received-to-result time were ~7 min, ~3 min, and ~13 min, respectively. The samples collected at the bedside had longer collect-to-received time than the ones collected at the blood draw site next to the laboratory. Compared to ED cTn test and ED HCG test, CPC cTn test took less time in each step. A combination of the sample type switch and the centrifugation time reduction contributed the most to the shortening of TAT, which was reflected in the received-to-result time.

CONCLUSIONS

The current process flow of CPC cTn test satisfied the requirements of chest pain management, giving an example of how to implement process improvement for emergency medicine to shorten TAT of laboratory tests.

Human Growth Factor/Immunoglobulin Complexes for Treatment of Myocardial Ischemia-Reperfusion Injury

Hepatocyte Growth Factor (HGF) and Fibroblast Growth Factor 2 (FGF2) are receptor tyrosine kinase agonists that promote cell survival after tissue injury and angiogenesis, cell proliferation and migration during tissue repair and regeneration. Both ligands have potential as systemic treatments for ischemia-reperfusion injury, however clinical use of HGF and FGF2 has been limited by poor pharmacokinetic profiles, i.e., their susceptibility to serum proteases, rapid clearance and short half-lives. Previously, we reported vaso- and cardioprotective protein complexes formed between HGF and polyclonal, non-specific immunoglobulin (IgG) with therapeutic efficacy in a rat model of myocardial ischemia with reperfusion (MI/R). Here, using a pre-clinical porcine MI/R model, we demonstrate human HGF/IgG complexes provide significant myocardial salvage, reduce infarct size, and are detectable in myocardial tissue 24 h after intracoronary injection. Furthermore, we show that multiple daily infusions of HGF/IgG complexes after MI do not lead to production of HGF-specific auto-antibodies, an important concern for administered biologic drugs. In experiments to identify other growth factors that non-covalently interact with IgG, we found that human FGF2 associates with IgG. Similar to human HGF/IgG complexes, FGF2/IgG complexes protected primary human cardiac endothelial cells under simulated ischemia (1% oxygen and nutrient deprivation) for 48–72 h. Molecular modeling studies suggested that FGF2 and HGF both interact with the Fc domain of IgG. Also, we tested whether an Fc-fusion protein would bind FGF2 to form complexes. By native gel electrophoretic assays and biochemical pulldowns, we found that Jagged1, a Notch1 ligand that controls stem cell self-renewal and tissue regeneration, bound FGF2 when presented as a Jagged1- Fc fusion protein. Our results suggest that human growth factor/IgG and FGF2/Fc- fusion complexes have potential to provide a biologics platform to treat myocardial ischemia-reperfusion and other forms of tissue injury.

Vasorelaxant and Antioxidant Effects of Aframomum pruinosum Gagnep. (Zingiberaceae) Seed Extracts May Mediate Their Cardioprotective Activity against Isoproterenol-Induced Myocardial Infarction

Aframomum pruinosum seeds are traditionally used in Cameroon to treat cardiac palpitations. The present work evaluates the cardioprotective effects of the aqueous (AE) and ethanolic (EE) extracts from A. pruinosum seeds against isoproterenol-induced myocardial infarction. Male Wistar rats were pretreated for 14 days with AE or EE at doses of 75 and 150 mg/kg/day or propranolol (10 mg/kg/day). On days 15 and 16, they were injected subcutaneously with isoproterenol (85 mg/kg/day). Blood pressure and heart rate were weekly recorded by tail-cuff plethysmography during pretreatment and 24 hours after the second dose of isoproterenol. At the end of the treatment period, serum Lactate Dehydrogenase (LDH), Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), cardiac nitric oxide (NO), myeloperoxidase (MPO), and oxidative stress parameters (SOD, catalase, MDA, and GSH) were assayed. Sections of left ventricle tissue were subjected to histological analysis. The vasorelaxant effects of cumulative concentrations of AE or EE (3–300 µg/mL) were evaluated on intact or endothelium-denuded isolated aorta rings precontracted with noradrenaline (1 µM). The vasorelaxant effects of the plant extracts were also tested in the presence of N^ω-nitro-L-arginine methyl ester (L-NAME; 100 µM). AE and EE significantly prevented blood pressure decrease and heart rate increase elicited by isoproterenol. Both plant extracts inhibited the increase in ALT, AST, NO, and MPO but did not prevent LDH surge. Oxidative stress parameters were improved following A. pruinosum pretreatment. AE and EE highly reduced cardiomyocyte necrosis and fibrosis but did not prevent leukocyte infiltration. Both extracts induced a concentration-dependent vasorelaxation that was significantly inhibited by the destruction of the endothelium and by L-NAME. Extracts of A. pruinosum exhibited cardioprotective effects, and EE was the most active. The cardioprotective effects of A. pruinosum extracts could be ascribed to their antioxidant, antinecrotic, and endothelium-dependent vasorelaxant effects.

Human Plasma Metabolomics Identify 9-cis-retinoic Acid and Dehydrophytosphingosine Levels as Novel biomarkers for Early Ventricular Fibrillation after ST-elevated Myocardial Infarction

The relevant metabolite biomarkers for risk prediction of early onset of ventricular fibrillation (VF) after ST-segment elevation myocardial infarction (STEMI) remain unstudied. Here, we aimed to identify these imetabolites and the important metabolic pathways involved, and explore whether these metabolites could be used as predictors for the phenotype. Plasma samples were obtained retrospectively from a propensity-score matched cohort including 42 STEMI patients (21 consecutive VF and 21 non-VF). Ultra-performance liquid chromatography and mass spectrometry in combination with a comprehensive analysis of metabolomic data using Metaboanalyst 5.0 version were performed. As a result, the retinal metabolism pathway proved to be the most discriminative for the VF phenotype. Furthermore, 9-cis-Retinoic acid (9cRA) and dehydrophytosphingosine proved to be the most discriminative biomarkers. Biomarker analysis through receiver operating characteristic (ROC) curve showed the 2-metabolite biomarker panel yielding an area under the curve (AUC) of 0.836. The model based on Monte Carlo cross-validation found that 9cRA had the greatest probability of appearing in the predictive panel of biomarkers in the model. Validation of model efficiency based on an ROC curve showed that the combination model constructed by 9cRA and dehydrophytosphingosine had a good predictive value for early-onset VF after STEMI, and the AUC was 0.884 (95% CI 0.714–1). Conclusively, the retinol metabolism pathway was the most powerful pathway for differentiating the post-STEMI VF phenotype. 9cRA was the most important predictive biomarker of VF, and a plasma biomarker panel made up of two metabolites, may help to build a potent predictive model for VF.

Impact of Delayed Pain to Needle and Variable Door to Needle Time On In-Hospital Complications in Patients With ST-Elevation Myocardial Infarction Who Underwent Thrombolysis: A Single-Center Experience

Background

Myocardial infarction is a life-threatening event, and timely intervention is essential to improve patient outcomes and mortality. Previous studies have shown that the time to thrombolysis should be less than 30 minutes of the patient’s arrival at the emergency room. Pain-to-needle time is a time from onset of chest pain to the initiation of thrombolysis, and door-to-needle time is a time between arrival to the emergency room to initiation of thrombolytic treatment. Ideally, the target for door-to-needle time should be less than 30 minutes; however, it is unclear if the door-to-needle time has a significant impact on patients presenting later than three hours from the onset of pain. As many of the previous studies were conducted in first-world countries, with established emergency medical services (EMS) systems and pre-hospital ST-elevation myocardial infarction (STEMI) triages and protocols, the data is not completely generalizable to developing countries. We, therefore, looked for the impact of the shorter and longer door-to-needle times on patient outcomes who presented to the emergency room (ER) with delayed pain-to-needle times (more than three hours of pain onset). 

Objective

To determine the impact of delayed pain-to-needle time (PNT) with variable door-to-needle time (DNT) on in-hospital complications (post-infarct angina, heart failure, left ventricular dysfunction, and death) in patients with ST-elevation myocardial infarction (STEMI) who underwent thrombolysis.

Methods and results

A total of 300 STEMI patients who underwent thrombolysis within 12 hours of symptoms onset were included, which were divided into two groups based on PNT. These groups were further divided into subgroups based on DNT. The primary outcome was in-hospital complications between the two groups and between subgroups within each group. The pain-to-needle time was ≤3 hours in 73 (24.3%) patients and >3 hours in 227 (75.7%) patients. In-hospital complications were higher in group II with PNT >3 hours (p <0.05). On subgroup analysis, in-hospital complications were higher with longer door-to-needle time in group II (p<0.05); however, there was no difference in complications among group I.

Conclusion

Our study is consistent with the fact that shorter door-to-needle time, even in patients with delayed PNT (>3 hours), has a significant impact on in-hospital complications with no difference in mortality.

Guidelines for in vivo mouse models of myocardial infarction

Despite significant improvements in reperfusion strategies, acute coronary syndromes all too often culminate in a myocardial infarction (MI). The consequent MI can, in turn, lead to remodeling of the left ventricle (LV), the development of LV dysfunction, and ultimately progression to heart failure (HF). Accordingly, an improved understanding of the underlying mechanisms of MI remodeling and progression to HF is necessary. One common approach to examine MI pathology is with murine models that recapitulate components of the clinical context of acute coronary syndrome and subsequent MI. We evaluated the different approaches used to produce MI in mouse models and identified opportunities to consolidate methods, recognizing that reperfused and nonreperfused MI yield different responses. The overall goal in compiling this consensus statement is to unify best practices regarding mouse MI models to improve interpretation and allow comparative examination across studies and laboratories. These guidelines will help to establish rigor and reproducibility and provide increased potential for clinical translation.

Quality of life in patients with stable coronary artery disease submitted to percutaneous, surgical, and medical therapies: a cohort study

Background

Clinical, surgical, and percutaneous strategies similarly prevent major cardiovascular events in patients with stable coronary artery disease (CAD). The possibility that these strategies have differential effects on health-related quality of life (HRQoL) has been debated, particularly in patients treated outside clinical trials.

Methods

We assigned 454 patients diagnosed with CAD during an elective diagnostic coronary angiography to coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or optimal medical treatment (OMT), and followed them for an average of 5.2 ± 1.5 years. HRQoL was assessed using a validated Brazilian version of the 12-Item Short-Form Health Survey questionnaire. The association between therapeutic strategies and quality of life scores was tested using variance analysis and adjusted for confounders in a general linear model.

Results

There were no differences in the mental component summary scores in the follow-up evaluation by therapeutic strategies: 51.4, 53.7, and 52.3 for OMT, PCI, and CABG, respectively. Physical component summary scores were higher in the PCI group than the CABG and OMT groups (46.4 vs. 42.9 and 43.8, respectively); however, these differences were no longer different after adjustment for confounding variables.

Conclusion

In a long-term follow-up of patients with stable CAD, HRQoL did not differ in patients treated by medical, percutaneous, or surgical treatments.

Correlates of Delayed Initial Contact to Emergency Services among Patients with Suspected ST-Elevation Myocardial Infarction

Background

Early diagnosis and treatment of a patient displaying symptoms of myocardial ischemia is paramount in preventing detrimental tissue damage, arrhythmias, and death. Patient-related hospital delay is the greatest considerable cause of total delay in treatment for acute myocardial infarction.

Objective

To identify patient characteristics contributing to prehospital delay and ultimately developing health interventions to prevent future delay and improve health outcomes.

Methods

A retrospective chart review of 287 patients diagnosed with ST-elevation myocardial infarction (STEMI) was evaluated to examine correlates of patient-related delays to care.

Results

Stepwise logistic regression modeling with forward selection (likelihood ratio) was performed to identify predictors of first medical contact (FMC) within 120 minutes of symptom onset and door-to-balloon (DTB) time within 90 minutes. Distance from the hospital, being unmarried, self-medicating, disability, and hemodynamic stability emerged as variables that were found to be predictive of FMC within the first 120 minutes after symptom onset. Similarly, patient characteristics of gender and disability and having an initial nondiagnostic electrocardiogram emerged as significant predictors of DTB within 90 minutes.

Conclusions

Individual attention to high-risk patients and public education campaigns using printed materials, public lectures, and entertainment mediums are likely needed to disseminate information to improve prevention strategies. Future research should focus on identifying the strengths of prehospital predictors and finding other variables that can be established as forecasters of delay. Interventions to enhance survival in acute STEMI should continue as to provide substantial advances in overall health outcomes.

Engineering the Cellular Microenvironment of Post-infarct Myocardium on a Chip

Myocardial infarctions are one of the most common forms of cardiac injury and death worldwide. Infarctions cause immediate necrosis in a localized region of the myocardium, which is followed by a repair process with inflammatory, proliferative, and maturation phases. This repair process culminates in the formation of scar tissue, which often leads to heart failure in the months or years after the initial injury. In each reparative phase, the infarct microenvironment is characterized by distinct biochemical, physical, and mechanical features, such as inflammatory cytokine production, localized hypoxia, and tissue stiffening, which likely each contribute to physiological and pathological tissue remodeling by mechanisms that are incompletely understood. Traditionally, simplified two-dimensional cell culture systems or animal models have been implemented to elucidate basic pathophysiological mechanisms or predict drug responses following myocardial infarction. However, these conventional approaches offer limited spatiotemporal control over relevant features of the post-infarct cellular microenvironment. To address these gaps, Organ on a Chip models of post-infarct myocardium have recently emerged as new paradigms for dissecting the highly complex, heterogeneous, and dynamic post-infarct microenvironment. In this review, we describe recent Organ on a Chip models of post-infarct myocardium, including their limitations and future opportunities in disease modeling and drug screening.

Bilateral Lung Artery Embolization Mimicking an Acute Myocardial Infarction

Electrocardiographic abnormalities in patients with massive pulmonary embolism are common and unspecific. An 80-year-old woman was admitted to our department with severe respiratory insufficiency and hemodynamic instability. Abnormal high-sensitivity cardiac troponin I and ST-segmental elevation in II, III, aVF, and V3–V6 were present on admission. Segmental motion abnormalities of the left ventricular wall were not detectable in echocardiography. Instead, the presence of a right ventricular strain raised the suspicion of a lung artery embolization. The diagnosis was confirmed by a computed tomography of the chest, and a thrombolytic therapy with 100 mg recombinant tissue plasminogen activator (rt-PA) was administered. Though respiratory and hemodynamic stability were established, electromechanical disassociation suddenly occurred 30 hours later and the patient died. Electrocardiographic changes mimicking a myocardial infarction may occur after a massive pulmonary embolism and constitute a diagnostic challenge for clinicians being active in the field of emergency medicine and intensive care.

Knockdown of ZFAS1 improved the cardiac function of myocardial infarction rats via regulating Wnt/β-catenin signaling pathway

Myocardial infarction (MI) is a big health threat in the world, and it is characterized by high morbidity and mortality. However, current treatments are not effective enough, and novel therapeutic strategies need to be explored. ZFAS1 has been proved to be involved in the regulation of MI, but the specific mechanism remains unclear. MI rats were constructed through left anterior descending artery ligation, and hypoxia cell model was also established. The proliferation, invasion, and migration of cells were detected via CCK8, traswell, and wound healing methods. Immunohistochemistry staining, western blotting, and qRT-PCR were used to detect the levels of molecules. Knockdown of ZFAS1 significantly increased the proliferation, migration, and invasion of cardiac fibroblasts. Knockdown of ZFAS1 remarkably improved cardiac function via decreasing infarction ratio and increasing vWF expression, left ventricular ejection fraction, and left ventricular fractional shortening compared with group MI. Knockdown of ZFAS1 also suppressed Wnt/β-catenin pathway in vivo. The inhibition of Wnt/β-catenin remarkably reversed the influence of shZFAS1 on cardiac function and cardiac fibroblasts viability. Therefore, Knockdown of ZFAS1 could improve the cardiac function of myocardial infarction rats via regulating Wnt/β-catenin signaling pathway. The present study might provide new thoughts for the prevention and treatment of MI damage.

Allicin attenuates myocardial apoptosis, inflammation and mitochondrial injury during hypoxia-reoxygenation: an in vitro study

Background

Myocardial ischemia–reperfusion (IR) injury is a damage due to an initial reduction in blood flow to the heart, preventing it from receiving enough oxygen, and subsequent restoration of blood flow through the opening of an occluded coronary artery producing paradoxical harmful effects. The finding of new therapies to prevent IR is of utmost importance. Allicin is a compound isolated from garlic having the ability to prevent and cure different diseases, and a protective effect on the myocardium was also demonstrated. Therefore, the aim of this study was to evaluate the in vitro protective effect of Allicin against myocardial IR injury on cardiomyocytes.

Methods

We established an in vitro hypoxia-reoxygenation (HR) model of primary porcine cardiomyocytes to simulate myocardial IR injury. Primary porcine cardiomyocytes were extracted from Mini-musk swines (1 day old). After a period of adaptation of at least 2–3 days, cardiomyocytes in good condition were selected and randomly divided into control group (normal oxygen for 5 h), HR group (2 h of hypoxia/3 h of reoxygenation), and HR + Allicin group (hypoxia/reoxygenation + Allicin treatment).

Results

After the induction of hypoxia/reoxygenation, Allicin treatment enhanced the cell viability. Moreover, Allicin treatment resulted in a reduction of apoptosis from 13.5 ± 1.2% to 6.11 ± 0.15% compared with the HR group (p < 0.05), and the apoptosis related proteins were regulated as well, with a decreased expression of Bax, cleaved caspase-3 and cytosolic cytochrome C and an increase in Bcl-2 expression in the HR + Allicin group (all p < 0.01). Pro-inflammatory cytokines, such as interleukin-6 and tumor necrosis factor alpha were down-regulated by the treatment with Allicin (both p < 0.01). In addition, it significantly decreased intracellular reactive oxygen species generation (p < 0.01) and reduced the loss of mitochondrial membrane potential (p < 0.01). Furthermore, the expression of PPARγ coactivator-1α and endothelial nitric oxide synthase was up-regulated (both p < 0.01), while the expression of Endothelin-1, hypoxia inducing factor-1α and transforming growth factor beta was down-regulated (all p < 0.01) by Allicin treatment.

Conclusions

These results suggested that Allicin protected the cardiomyocytes against HR damage by reducing apoptosis, inflammation and mitochondrial injury, thus providing a basis for its potential use in the treatment of myocardial IR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-01918-6.

Door-to-unload: left ventricular unloading before reperfusion in ST-elevation myocardial infarction

ST-elevation myocardial infarction treatment in the modern era has focused on minimizing time of ischemia by reducing door-to-balloon time to limit infarct size and improve survival. Although there have been significant improvements in minimizing time to coronary reperfusion, the incidence of heart failure following a myocardial infarction has remained high. Preclinical studies have shown that unloading the left ventricle for 30 min prior to coronary reperfusion can reduce infarct size and promote myocardial recovery. The DTU-STEMI randomized prospective trial will test the hypothesis that left ventricular unloading for at least 30 min prior to coronary reperfusion will improve infarct size and heart failure-related events as compared with the current standard of care.

Phosphorylcholine Antibodies Preserve Cardiac Function and Reduce Infarct Size by Attenuating the Post-Ischemic Inflammatory Response

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Phosphorylcholine is a proinflammatory epitope exposed on the outer membrane of apoptotic cells.

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This study investigated the modulatory effects of a fully human IgG1 monoclonal antibody directed against phosphorylcholine (PC-mAb) on myocardial remodeling and cardiac function following myocardial ischemia-reperfusion injury.

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PC-mAb attenuates the immediate post-ischemic inflammatory response by reducing the proinflammatory CCL2 chemokine and circulating Ly-6C^hi monocytes. This subsequently enhances the post-ischemic repair process resulting in limited adverse cardiac remodeling and preservation of cardiac function.

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PC-mAb therapy may be a valid therapeutic approach against myocardial ischemia-reperfusion injury.

Phosphorylcholine monoclonal immunoglobulin G antibody attenuates the immediate post-ischemic inflammatory response by reducing the proinflammatory chemokine (C-C motif) ligand 2 chemokine and circulating Ly-6C^hi monocytes. This subsequently enhances the post-ischemic repair process, resulting in limited adverse cardiac remodeling and preservation of cardiac function. Therefore, phosphorylcholine monoclonal immunoglobulin G antibody therapy may be a valid therapeutic approach against myocardial ischemia-reperfusion injury.

The protective effects of different compatibility proportions of the couplet medicines for Astragali Radix and Angelica sinensis Radix on myocardial infarction injury

Context: Astragali Radix (AR) and Angelica sinensis Radix (ASR) combinations are used to treat cardiovascular disorders.Objectives: This study investigates the protective effects of different compatibility proportions of AR and ASR on cardiac dysfunction in a C57BL/6 mouse model of myocardial infarction (MI).Materials and methods: MI mice were induced by ligation of the left coronary artery and divided into six groups: sham, vehicle, 10 mg/kg/d simvastatin and combinations of AR and ASR at different ratios, including 1:1 (AR 2.5 g/kg + ASR 2.5 g/kg), 3:1 (AR 3.75 g/kg + ASR 1.25 g/kg) and 5:1 (AR 4.17 g/kg + ASR 0.83 g/kg). Both AR-ASR combinations and simvastatin were dissolved in saline solution and given daily by gavage. The left ventricle function, infarct size, heart tissue injury, apoptosis of cardiomyocytes, leukocyte infiltrates, capillary density and expression of cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, Bad, IL-1β, IL-6, VEGF, p-Akt and p-eNOS were analysed.Results: Different combinations of AR and ASR improve cardiac function and reduce infarct size (61.15% vs. 39.3%, 42.65% and 45.5%) and tissue injury through different mechanisms. When AR was combined with ASR at ratio of 1:1, the inflammation and cardiomyocyte apoptosis were suppressed (p < 0.05, p < 0.01). The combination ratio of 3:1 exerted effect in promoting angiogensis (p < 0.05). In the combination of AR and ASR at 5:1 ratio, angiogenesis was significantly improved (p < 0.01) and the apoptosis was inhibited (p < 0.05).Conclusions: Our results reflect the regulation of multiple targets and links in herb pairs and provide an important basis for the use of AR and ASR combinations in the treatment of MI.

The impact of the Type D Personality pattern on prehospital delay in patients suffering from acute myocardial infarction

Background

The Type D Personality (TDP) has been specifically linked to acute myocardial infarction (AMI). However, the impact on prehospital delay of AMI patients is unclear. The aim of this study was to assess the relationship between TDP and pre-hospital delay time (PHT) in a Chinese population.

Methods

A total of 256 AMI patients (47 women and 209 men) were taken from the Multicenter Delay in Patients Experiencing AMI in Shanghai (MEDEA FAR-EAST) study. Sociodemographic and psycho-behavioral characteristics were assessed by bedside interviews and questionnaires. TDP was evaluated according to the Type D Personality Scale (DS14) subdivided in social inhibition (SI) and negative affectivity (NA). Based on a significant interaction analysis of TDP and sex on PHT, all analyses were stratified by sex.

Results

PHT of female patients with TDP were substantially shorter compared to non-TDP female patients (108 vs. 281 min, P=0.029). In male patients, no effect of TDT on PHT was found. Spearman correlation analysis suggests that NA was negatively correlated with PHT (r=−0.358, P=0.014). Further age-adjusted logistic regression analyses showed that female patients with TDP were generally less likely to prehospital delay compared with non-TDP patients (OR =0.28; 95% CI, 0.08–0.98) and had a lower risk of PHT >360 minutes (OR =0.10; 95% CI, 0.01–0.91). However, statistical significance disappeared after adjustment for psychological factors (anxiety, depression, suboptimal wellbeing, cardiac denial and stress event).

Conclusions

TDP is associated with less prehospital delay in female patients during AMI—an effect which may be particularly mediated by NA.

Angiogenesis after acute myocardial infarction

Acute myocardial infarction (MI) inflicts massive injury to the coronary microcirculation leading to vascular disintegration and capillary rarefication in the infarct region. Tissue repair after MI involves a robust angiogenic response that commences in the infarct border zone and extends into the necrotic infarct core. Technological advances in several areas have provided novel mechanistic understanding of postinfarction angiogenesis and how it may be targeted to improve heart function after MI. Cell lineage tracing studies indicate that new capillary structures arise by sprouting angiogenesis from pre-existing endothelial cells (ECs) in the infarct border zone with no meaningful contribution from non-EC sources. Single-cell RNA sequencing shows that ECs in infarcted hearts may be grouped into clusters with distinct gene expression signatures, likely reflecting functionally distinct cell populations. EC-specific multicolour lineage tracing reveals that EC subsets clonally expand after MI. Expanding EC clones may arise from tissue-resident ECs with stem cell characteristics that have been identified in multiple organs including the heart. Tissue repair after MI involves interactions among multiple cell types which occur, to a large extent, through secreted proteins and their cognate receptors. While we are only beginning to understand the full complexity of this intercellular communication, macrophage and fibroblast populations have emerged as major drivers of the angiogenic response after MI. Animal data support the view that the endogenous angiogenic response after MI can be boosted to reduce scarring and adverse left ventricular remodelling. The improved mechanistic understanding of infarct angiogenesis therefore creates multiple therapeutic opportunities. During preclinical development, all proangiogenic strategies should be tested in animal models that replicate both cardiovascular risk factor(s) and the pharmacotherapy typically prescribed to patients with acute MI. Considering that the majority of patients nowadays do well after MI, clinical translation will require careful selection of patients in need of proangiogenic therapies.

Basic Fibroblast Growth Factor Attenuates Injury in Myocardial Infarction by Enhancing Hypoxia-Inducible Factor-1 Alpha Accumulation

Background

The combination of antiapoptotic and angiogenic actions may represent a pharmacotherapeutic strategy for the treatment of myocardial infarction. Fibroblast growth factor (FGF) is expressed in various cell types including endothelial and muscle cells and promotes their survival, migration, and proliferation.

Methods and Results

Myocardial microvascular endothelial cells were divided into four treatment groups, the sham, hypoxia, basic FGF (bFGF), and bFGF plus 2-methoxyestradiol groups, and subjected to in vitro apoptotic analysis and Matrigel assays. An in vivo model of myocardial infarction was established by ligaturing the left coronary artery of mice in the four treatment groups. Cardiac performance, myocardial injury, endothelial cell angiogenesis, and myocardial apoptosis were assessed. bFGF administration after myocardial infarction improved cardiac function and cell viability, attenuated myocardial injury and apoptosis, and enhanced angiogenesis. Western blotting of HIF-1α, p-AKT, VEGF, p53, BAX, and Bcl-2 showed that bFGF increased HIF-1α, p-AKT, VEGF, and Bcl-2 and decreased BAX protein levels.

Conclusion

The results of the present study indicated that bFGF attenuates myocardial injury by inhibiting apoptosis and promoting angiogenesis via a novel HIF-1α-mediated mechanism and a potential utility of bFGF in protecting against myocardial infarction.

[Melatonin protects against myocardial ischemia-reperfusion injury by inhibiting contracture in isolated rat hearts]

OBJECTIVE

To investigate the protective effect of melatonin against myocardial ischemia reperfusion (IR) injury in isolated rat hearts and explore the underlying mechanisms.

METHODS

The isolated hearts from 40 male SD rats were randomly divided into 4 groups (n=10): the control group, where the hearts were perfused with KH solution for 175 min; IR group, where the hearts were subjected to global ischemia for 45 min followed by reperfusion for 120 min; IR+melatonin (Mel+IR) group, where melatonin (5 μmol/L) was administered to the hearts 1 min before ischemia and during the first 5 min of reperfusion, followed by 115 min of reperfusion; and IR+2, 3-butanedione monoxime (IR+BDM) group, where the hearts were treated with BDM (20 mmol/L) in the same manner as melatonin treatment. Myocardial injury in the isolated hearts was assessed based on myocardial injury area, caspase-3 activity, and expressions of cytochrome C and cleaved caspase-3 proteins. Cardiac contracture was assessed using HE staining and by detecting lactate dehydrogenase (LDH) activity and the content of cardiac troponin I (cTnI) in the coronary outflow, measurement of left ventricular end-diastolic pressure (LVEDP) and electron microscopy. The content of ATP in the cardiac tissue was also determined.

RESULTS

Compared with those in the control group, the isolated hearts in IR group showed significantly larger myocardial injury area and higher caspase-3 activity and the protein expressions of cytochrome C and cleaved caspase-3 with significantly increased LDH activity and cTnI content in the coronary outflow and elevated LVEDP at the end of reperfusion; HE staining showed obvious fractures of the myocardial fibers and the content of ATP was significantly decreased in the cardiac tissue; electron microscopy revealed the development of contraction bands. In the isolated hearts with IR, treatment with Mel or BDM significantly reduced the myocardial injury area, caspase-3 activity, and protein expressions of cytochrome C and cleaved caspase-3, obviously inhibited LDH activity, lowered the content of cTnI and LVEDP, reduced myocardial fiber fracture, and increased ATP content in the cardiac tissue. Both Mel and BDM inhibited the formation of contraction bands in the isolated hearts with IR injury.

CONCLUSIONS

Mel can alleviate myocardial IR injury in isolated rat hearts by inhibiting cardiac contracture, the mechanism of which may involve the upregulation of ATP in the cardiac myocytes to lessen the tear of membrane and reduce cell content leakage.

Ferulic acid protects cardiomyocytes from TNF-α/cycloheximide-induced apoptosis by regulating autophagy

Acute myocardial infarction (AMI) results in irreversible cardiac cell damage or death because of decreased blood flow to the heart. Apoptosis plays an important role in the process of tissue damage after myocardial infarction (MI), which has pathological and therapeutic implications. Ferulic acid (FA) is a phenolic acid endowed with strong antioxidative and cytoprotective activities. The present study aimed to investigate whether FA protects cardiomyocytes from apoptosis by regulating autophagy, which is a cellular self-digestion process, and one of the first lines of defense against oxidative stress. Apoptosis was induced by TNF-α (10 ng/mL) and cycloheximide (CHX, 5 μg/mL) in rat H9c2 cardiomyocytes. FA-inhibited TNF-α/CHX-induced apoptosis was determined by the quantification of TUNEL-positive cells, and the effect was associated with decreased ROS production and inhibited caspase3 activation. FA treatment enhanced autophagy and increased autophagy-associated protein expression, leading to an inhibition of mTOR signaling. When co-treated with 3-methyladenine (3-MA), an autophagy inhibitor, the anti-apoptotic effect of FA was attenuated. In an in vivo mouse MI model, FA treatment decreased the apoptotic cell number, reduced infarct size, and improved cardiac performance, as determined by histological and echocardiographic assessments. Taken collectively, these results suggest that FA could protect cardiomyocytes from apoptosis by enhancing autophagy.

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.

C-X-C Motif Chemokine Receptor 4 Blockade Promotes Tissue Repair After Myocardial Infarction by Enhancing Regulatory T Cell Mobilization and Immune-Regulatory Function

BACKGROUND

Acute myocardial infarction (MI) elicits an inflammatory response that drives tissue repair and adverse cardiac remodeling. Inflammatory cell trafficking after MI is controlled by C-X-C motif chemokine ligand 12 (CXCL12) and its receptor, C-X-C motif chemokine receptor 4 (CXCR4). CXCR4 antagonists mobilize inflammatory cells and promote infarct repair, but the cellular mechanisms are unclear.

METHODS

We investigated the therapeutic potential and mode of action of the peptidic macrocycle CXCR4 antagonist POL5551 in mice with reperfused MI. We applied cell depletion and adoptive transfer strategies using lymphocyte-deficient Rag1 knockout mice; DEREG mice, which express a diphtheria toxin receptor-enhanced green fluorescent protein fusion protein under the control of the promoter/enhancer region of the regulatory T (T_reg) cell-restricted Foxp3 transcription factor; and dendritic cell-depleted CD11c-Cre iDTR mice. Translational potential was explored in a porcine model of reperfused MI using serial contrast-enhanced magnetic resonance imaging.

RESULTS

Intraperitoneal POL5551 injections in wild-type mice (8 mg/kg at 2, 4, 6, and 8 days) enhanced angiogenesis in the infarct border zone, reduced scar size, and attenuated left ventricular remodeling and contractile dysfunction at 28 days. Treatment effects were absent in splenectomized wild-type mice, Rag1 knockout mice, and T_reg cell-depleted DEREG mice. Conversely, treatment effects could be transferred into infarcted splenectomized wild-type mice by transplanting splenic T_reg cells from POL5551-treated infarcted DEREG mice. Instructive cues provided by infarct-primed dendritic cells were required for POL5551 treatment effects. POL5551 injections mobilized T_reg cells into the peripheral blood, followed by enhanced T_reg cell accumulation in the infarcted region. Neutrophils, monocytes, and lymphocytes displayed similar mobilization kinetics, but their cardiac recruitment was not affected. POL5551, however, attenuated inflammatory gene expression in monocytes and macrophages in the infarcted region via T_reg cells. Intravenous infusion of the clinical-stage POL5551 analogue POL6326 (3 mg/kg at 4, 6, 8, and 10 days) decreased infarct volume and improved left ventricular ejection fraction in pigs.

CONCLUSIONS

These data confirm CXCR4 blockade as a promising treatment strategy after MI. We identify dendritic cell-primed splenic T_reg cells as the central arbiters of these therapeutic effects and thereby delineate a pharmacological strategy to promote infarct repair by augmenting T_reg cell function in vivo.

Temporal Trends in Utilization of Cardiac Therapies and Outcomes for Myocardial Infarction by Degree of Chronic Kidney Disease: A Report From the NCDR Chest Pain-MI Registry

Background

We sought to determine temporal trends in use of evidence‐based therapies and clinical outcomes among myocardial infarction (MI) patients with chronic kidney disease (CKD).

Methods and Results

MI patients from the NCDR (National Cardiovascular Data Registry) Chest Pain–MI Registry between January 2007 and December 2015 were categorized into 3 groups by degree of CKD (end‐stage renal disease on dialysis, CKD [glomerular filtration rate <60 mL/min per 1.73 m²] not requiring dialysis, and no CKD [glomerular filtration rate ≥60 mL/min per 1.73 m²]). Logistic regression modeling was used to determine the association between calendar years (2014–2015 versus 2007–2008) and each outcome by degree of CKD. Among 325 396 patients with ST‐segment–elevation MI, 1.0% had end‐stage renal disease requiring dialysis, and 26.1% had CKD not requiring dialysis. Use of primary percutaneous coronary intervention increased over time regardless of the presence or degree of CKD (P=0.40 for interaction). In‐hospital mortality was temporally higher among patients with preserved renal function (odds ratio: 1.25; 95% confidence interval, 1.13–1.39; P<0.001) but not among patients with CKD (P=0.035 for interaction). Among 506 876 non–ST‐segment–elevation MI patients, 3.4% had end‐stage renal disease requiring dialysis, and 34.4% had CKD not requiring dialysis. P2Y₁₂ inhibitor use within 24 hours increased over time only among dialysis patients (P for interaction <0.001). Use of coronary angiography and percutaneous coronary intervention also increased, with the greatest increase among dialysis patients (P for interaction <0.001 and <0.001, respectively). In‐hospital mortality was lower, regardless of the presence or degree of CKD (P=0.64 for interaction).

Conclusions

Uptake of evidence‐based medical and invasive therapies has increased over the past decade among MI patients with CKD, particularly dialysis patients, with improvement of in‐hospital mortality observed among patients with non–ST‐segment–elevation MI, but not ST‐segment–elevation MI, and CKD.

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Control of fibrinolytic drug injection via real-time ultrasonic monitoring of blood coagulation

In the present study, we investigated the capabilities of a novel ultrasonic approach for real-time control of fibrinolysis under flow conditions. Ultrasonic monitoring was performed in a specially designed experimental in vitro system. Fibrinolytic agents were automatically injected at ultrasonically determined stages of the blood clotting. The following clots dissolution in the system was investigated by means of ultrasonic monitoring. It was shown, that clots resistance to fibrinolysis significantly increases during the first 5 minutes since the formation of primary micro-clots. The efficiency of clot lysis strongly depends on the concentration of the fibrinolytic agent as well as the delay of its injection moment. The ultrasonic method was able to detect the coagulation at early stages, when timely pharmacological intervention can still prevent the formation of macroscopic clots in the experimental system. This result serves as evidence that ultrasonic methods may provide new opportunities for real-time monitoring and the early pharmacological correction of thrombotic complications in clinical practice.

Trop2 Guarantees Cardioprotective Effects of Cortical Bone-Derived Stem Cells on Myocardial Ischemia/Reperfusion Injury

Stem cell transplantation represents a promising therapeutic approach for myocardial ischemia/reperfusion (I/R) injury, where cortical bone-derived stem cells (CBSCs) stand out and hold superior cardioprotective effects on myocardial infarction than other types of stem cells. However, the molecular mechanism underlying CBSCs function on myocardial I/R injury is poorly understood. In a previous study, we reported that Trop2 (trophoblast cell-surface antigen 2) is expressed exclusively on the CBSCs membrane, and is involved in regulation of proliferation and differentiation of CBSCs. In this study, we found that the Trop2 is essential for the ameliorative effects of CBSCs on myocardial I/R-induced heart damage via promoting angiogenesis and inhibiting cardiomyocytes apoptosis in a paracrine manner. Trop2 is required for the colonization of CBSCs in recipient hearts. When Trop2 was knocked out, CBSCs largely lost their functions in lowering myocardial infarction size, improving heart function, enhancing capillary density, and suppressing myocardial cell death. Mechanistically, activating the AKT/GSK3β/β-Catenin signaling axis contributes to the essential role of Trop2 in CBSCs-rendered cardioprotective effects on myocardial I/R injury. In conclusion, maintaining the expression and/or activation of Trop2 in CBSCs might be a promising strategy for treating myocardial infarction, I/R injury, and other related heart diseases.

EMC10 (Endoplasmic Reticulum Membrane Protein Complex Subunit 10) Is a Bone Marrow-Derived Angiogenic Growth Factor Promoting Tissue Repair After Myocardial Infarction

BACKGROUND

Clinical trials of bone marrow cell-based therapies after acute myocardial infarction (MI) have produced mostly neutral results. Treatment with specific bone marrow cell-derived secreted proteins may provide an alternative biological approach to improving tissue repair and heart function after MI. We recently performed a bioinformatic secretome analysis in bone marrow cells from patients with acute MI and discovered a poorly characterized secreted protein, EMC10 (endoplasmic reticulum membrane protein complex subunit 10), showing activity in an angiogenic screen.

METHODS

We investigated the angiogenic potential of EMC10 and its mouse homolog (Emc10) in cultured endothelial cells and infarcted heart explants. We defined the cellular sources and function of Emc10 after MI using wild-type, Emc10-deficient, and Emc10 bone marrow-chimeric mice subjected to transient coronary artery ligation. Furthermore, we explored the therapeutic potential of recombinant Emc10 delivered by osmotic minipumps after MI in heart failure-prone FVB/N mice.

RESULTS

Emc10 signaled through small GTPases, p21-activated kinase, and the p38 mitogen-activated protein kinase (MAPK)-MAPK-activated protein kinase 2 (MK2) pathway to promote actin polymerization and endothelial cell migration. Confirming the importance of these signaling events in the context of acute MI, Emc10 stimulated endothelial cell outgrowth from infarcted mouse heart explants via p38 MAPK-MK2. Emc10 protein abundance was increased in the infarcted region of the left ventricle and in the circulation of wild-type mice after MI. Emc10 expression was also increased in left ventricular tissue samples from patients with acute MI. Bone marrow-derived monocytes and macrophages were the predominant sources of Emc10 in the infarcted murine heart. Emc10 KO mice showed no cardiovascular phenotype at baseline. After MI, however, capillarization of the infarct border zone was impaired in KO mice, and the animals developed larger infarct scars and more pronounced left ventricular remodeling compared with wild-type mice. Transplanting KO mice with wild-type bone marrow cells rescued the angiogenic defect and ameliorated left ventricular remodeling. Treating FVB/N mice with recombinant Emc10 enhanced infarct border-zone capillarization and exerted a sustained beneficial effect on left ventricular remodeling.

CONCLUSIONS

We have identified Emc10 as a previously unknown angiogenic growth factor that is produced by bone marrow-derived monocytes and macrophages as part of an endogenous adaptive response that can be enhanced therapeutically to repair the heart after MI.

Critical Issues for the Translation of Cardioprotection

The translation from numerous successful animal experiments on cardioprotection beyond that by reperfusion to clinical practice has to date been disappointing. Animal experiments often use reductionist approaches and are mostly performed in young and healthy animals which lack the risk factors, comorbidities, and comedications which are characteristics of patients suffering an acute myocardial infarction or undergoing cardiovascular surgery. Conceptually, it is still unclear by how much the time window for successful reperfusion is extended by preconditioning, and how long the duration of ischemia can be so that adjunct cardioprotection by postconditioning at reperfusion still protects. Experimental studies addressing long-term effects of adjunct cardioprotection beyond infarct size reduction, that is, on repair, remodeling, and mortality, are lacking. Technically, reproducibility and robustness of experimental studies are often limited. Grave faults in design and conduct of clinical trials have also substantially contributed to the failure of translation of cardioprotection to clinical practice. Cardiovascular surgery with ischemic cardioplegic arrest is only a surrogate of acute myocardial infarction and confounded by the choice of anesthesia, hypothermia, cardioplegia, and traumatic myocardial injury. Trials in patients with acute myocardial infarction have been performed on agents/interventions with no or inconsistent previous animal data and in patients who had either some reperfusion already at admission or were reperfused too late to expect any myocardial salvage. Of greatest concern is the lack of adequate phase II dosing and timing studies when rushing from promising proof-of-concept trials with surrogate end points such as infarct size to larger clinical outcome trials. Future trials must focus on interventions/agents with robust preclinical evidence, have solid phase II dosing and timing data, and recruit patients who have truly a chance to benefit from adjunct cardioprotection.

Intracoronary delivery of recombinant TIMP-3 after myocardial infarction: effects on myocardial remodeling and function

Ischemia-reperfusion (IR) and myocardial infarction (MI) cause adverse left ventricular (LV) remodeling and heart failure and are facilitated by an imbalance in matrix metalloproteinase (MMP) activation and the endogenous tissue inhibitors of metalloproteinase (TIMPs). We have identified that myocardial injections of recombinant TIMP-3 (rTIMP-3; human full length) can interrupt post-MI remodeling. However, whether and to what degree intracoronary delivery of rTIMP-3 post-IR is feasible and effective remained to be established. Pigs (25 kg) underwent coronary catheterization and balloon occlusion of the left anterior descending coronary artery (LAD) for 90 min whereby at the final 4 min, rTIMP-3 (30 mg, n = 9) or saline was infused in the distal LAD. LV echocardiography was performed at 3-28 days post-IR, and LV ejection fraction (EF) and LV end-diastolic volume were measured. LV EF fell and LV end-diastolic volume increased from baseline (pre-IR) values (66 ± 1% and 40 ± 1 ml, respectively, means ± standard deviation) in both groups; however, the extent of LV dilation was reduced in the rTIMP-3 group by 40% at 28 days post-IR (P < 0.05) and the fall in LV EF was attenuated. Despite equivalent plasma troponin levels (14 ± 3 ng/ml), computed MI size at 28 days was reduced by over 45% in the rTIMP-3 group (P < 0.05), indicating that rTIMP-3 treatment abrogated MI expansion post-IR. Plasma NH₂-terminal pro-brain natriuretic peptide levels, an index of heart failure progression, were reduced by 25% in the rTIMP-3 group compared with MI saline values (P < 0.05). Although the imbalance between MMPs and TIMPs has been recognized as a contributory factor for post-MI remodeling, therapeutic strategies targeting this imbalance have not been forthcoming. This study is the first to demonstrate that a relevant delivery approach (intracoronary) using rTIMP can alter the course of post-MI remodeling.NEW & NOTEWORTHY Myocardial ischemia and reperfusion injury remain significant causes of morbidity and mortality whereby alterations in the balance between matrix metalloproteinase and tissue inhibitor of metalloproteinase have been identified as contributory biological mechanisms. This novel translational study advances the concept of targeted delivery of recombinant proteins to modify adverse myocardial remodeling in ischemia-reperfusion injury.

Predictors of pre-hospital delay in Hong Kong Chinese patients with acute myocardial infarction

BACKGROUND

The pre-hospital delay to seek care remains the most significant barrier for effective management of acute myocardial infarction. Many of the previous studies mainly took place in Western countries. Few data are available about the care-seeking behavior of Hong Kong Chinese.

AIM

The purpose of this study was to identify the predictors of pre-hospital delay in care seeking among Hong Kong Chinese patients with acute myocardial infarction.

METHODS

Adult Chinese patients ( n=301) with a confirmed diagnosis of acute myocardial infarction were recruited from the cardiac units of three regional hospitals in Hong Kong. Various socio-demographic, clinical, symptom presentation characteristics and patient perceptual factors were considered as potential predictors. Multivariate analysis was conducted to identify the independent predictors with pre-hospital delay in care-seeking among acute myocardial infarction patients.

RESULTS

Perceived barriers to care seeking constituted the most significant predictor for longer pre-hospital delay in acute myocardial infarction patients. Female gender was also significant in predicting longer delay, whereas a greater extent of symptom congruence and a greater extent of typical symptom presentation were significantly associated with a shorter delay. The final model accounted for 49.6% of the variance in pre-hospital delay as a whole.

CONCLUSION

The most prominent predictors of pre-hospital delay are modifiable in nature, including the perceived barriers to care seeking and symptom congruence. Other sociodemographic and clinical factors also influence patients' decision. Although these are non-modifiable, our findings provide important insight for educating high-risk individuals.

The modified Yi qi decoction protects cardiac ischemia-reperfusion induced injury in rats

BACKGROUND

To investigate the effects and involved mechanisms of the modified Yi Qi decoction (MYQ) in cardiac ischemia-reperfusion (IR) induced injury.

METHODS

Male Sprague-Dawley rats were subjected to a 30-min coronary arterial occlusion followed by reperfusion, low or high dose decoction of MYQ was administrated orally for 1 week or 1 month.

RESULTS

Both in 1 week and 1 month IR rat groups, cardiac function indexes were significantly impaired compared with sham group rats, accompanied with higher ratio of infarct size to risk size, decreased expressions of sodium calcium exchanger (NCX1) and sarcoplasmic reticulum Ca2+-ATPase (Serca2a), and different expressions of autophagic proteins, Beclin-1 and LC3. Treatment with MYQ (low or high dose) for 1 week showed no marked beneficial effects on cardiac function and cardiac injury (ratio of infarct size to risk size), although expressions of anti-apoptotic protein, Bcl-2, NCX1 and Serca2a were increased. Treatment with MYQ (low or high dose) for 1 month showed significantly improved effects on cardiac function and cardiac injury (ratio of infarct size to risk size), accompanied with increase of Bcl-2, NCX1 and Serca2a expressions, and decrease of Bax (a pro-apoptotic protein) and Beclin-1 expressions.

CONCLUSIONS

The results show that MYQ have potential therapeutic effects on IR-induced cardiac injury, which may be through regulation of apoptotic proteins, cytosolic Ca2+ handling proteins and autophagic proteins signal pathways.

PPARγ-Coactivator-1α, Nicotinamide Adenine Dinucleotide and Renal Stress Resistance

With one of the highest mitochondrial densities in the body, the kidneys consume approximately 10% of total oxygen while constituting 0.5% of body mass. Renal respiration is linear to solute extraction, linking oxidative metabolism directly to tubular function. This fundamental role of mitochondria in renal health may become an "Achilles heel" under duress. Acute kidney injury (AKI) related to each major class of stressor - inflammation, ischemia, and toxins - exhibits early and prominent mitochondrial injury. The mitochondrial biogenesis regulator, PPARγ-coactivator-1α (PGC1α), may confer tubular protection against these stressors. Recent work proposes that renal PGC1α directly increases levels of nicotinamide adenine dinucleotide (NAD+), an essential co-factor for energy metabolism that has lately been proposed as an anti-aging factor. This mini-review summarizes recent studies on AKI, PGC1α, and NAD+ that identify a direct mechanism between the regulation of metabolic health and the ability to resist renal stressors.