Engineered Exosomes with Growth Differentiation Factor-15 Overexpression Enhance Cardiac Repair After Myocardial Injury.

Background: Cardiac repair remains a thorny issue for survivors of acute myocardial infarction (AMI), due to the regenerative inertia of myocardial cells. Cell-free therapies, such as exosome transplantation, have become a potential strategy for myocardial injury. The aim of this study was to investigate the role of engineered exosomes in overexpressing Growth Differentiation Factor-15 (GDF-15) (GDF15-EVs) after myocardial injury, and their molecular mechanisms in cardiac repair. Methods: H9C2 cells were transfected with GDF-15 lentivirus or negative control. The exosomes secreted from H9C2 cells were collected and identified. The cellular apoptosis and autophagy of H2O2-injured H9C2 cells were assessed by Western blotting, TUNEL assay, electron microscopy, CCK-8 and caspase 3/7 assay. A rat model of AMI was constructed by ligating the left anterior descending artery. The anti-apoptotic, pro-angiogenic effects of GDF15-EVs treatment, as well as ensuing functional and histological recovery were evaluated. Then, mRNA sequencing was performed to identify the differentially expressed mRNAs after GDF15-EVs treatment. Results: GDF15-EVs inhibited apoptosis and promoted autophagy in H2O2 injured H9C2 cells. GDF15-EVs effectively decreased the infarct area and enhanced the cardiac function in rats with AMI. Moreover, GDF15-EVs hindered inflammatory cell infiltration, inhibited cell apoptosis, and promoted cardiac angiogenesis in rats with AMI. RNA sequence showed that telomerase reverse transcriptase (TERT) mRNA was upregulated in GDF15-EVs-treated H9C2 cells. AMPK signaling was activated after GDF15-EVs. Silencing TERT impaired the protective effects of GDF15-EVs on H2O2-injured H9C2 cells. Conclusion: GDF15-EVs could fulfil their protective effects against myocardial injury by upregulating the expression of TERT and activating the AMPK signaling pathway. GDF15-EVs might be exploited to design new therapies for AMI.

Extracellular vesicle mediated targeting delivery of growth differentiation factor-15 improves myocardial repair by reprogramming macrophages post myocardial injury.

OBJECTIVE: Extracellular vesicles (EVs) have garnered considerable attention among researchers as candidates for natural drug delivery systems. This study aimed to investigate whether extracellular vesicle mediated targeting delivery of growth differentiation factor-15 (GDF15) improves myocardial repair by reprogramming macrophages post myocardial injury. METHODS: EVs were isolated from macrophages transfected with GDF15 (EXO-GDF15) and control macrophages (EXO-NC). In vitro and vivo experiments, we compared their reprogram ability of macrophages and regeneration activity. Furthermore, proteomic analysis were employed to determine the specific mechanism by which GDF15 repairs the myocardium. RESULTS: Compared with EXO-NC, EXO-GDF15 significantly regulated macrophage phenotypic shift, inhibited cardiomyocyte apoptosis, and enhanced endothelial cell angiogenesis. Moreover, EXO-GDF15 also significantly regulated macrophage heterogeneity and inflammatory cytokines, reduced fibrotic area, and enhanced cardiac function in infarcted rats. Proteomic analysis revealed a decrease in fatty acid-binding protein 4 (FABP4) protein expression following treatment with EXO-GDF15. Mechanistically, the reprogramming of macrophages by EXO-GDF15 is accomplished through the activation of Smad2/3 phosphorylation, which subsequently inhibits the production of FABP4. CONCLUSIONS: Extracellular vesicle mediated targeting delivery of growth differentiation factor-15 improves myocardial repair by reprogramming macrophages post myocardial injury via down-regulating the expression of FABP4. EXO-GDF15 may serve as a promising approach of immunotherapy.

Dapagliflozin reduces risk of heart failure rehospitalization in diabetic acute myocardial infarction patients: a propensity score-matched analysis.

OBJECTIVE: The aim of this study was to investigate the effect of dapagliflozin (DAPA) on the rate of heart failure rehospitalization in patients with acute myocardial infarction (AMI) and type 2 diabetes mellitus (T2DM). METHODS: AMI patients with T2DM from CZ-AMI registry between January 2017 and January 2021 were enrolled in this study. Patients were stratified into DAPA users and non-DAPA users. The primary outcome was the incidence of heart failure rehospitalization. Kaplan-Meier analysis and Cox regressions were performed to evaluate the prognostic significance of DAPA. Propensity score matching (PSM) was performed to minimize the bias of confounding factors and facilitate the comparability between groups. The enrolled patients were matched with a propensity score of 1:1. RESULTS: A total of 961 patients were included, and 132 (13.74%) heart failure rehospitalizations occurred during a median follow-up of 540 days. In the Kaplan-Meier analysis, DAPA users had a statistically significantly lower rate of heart failure rehospitalization than non-DAPA users (p < 0.0001). Multivariate Cox analysis showed that DAPA was an independent protective factor for heart failure rehospitalization risk after discharge (HR = 0.498, 95% CI = 0.296 ~ 0.831, p = 0.001). After 1:1 propensity score matching, survival analysis showed a lower cumulative risk of heart failure rehospitalization in DAPA users than in non-DAPA users (p = 0.0007). In-hospital and continued use of DAPA remained significantly associated with a reduced risk of heart failure rehospitalization (HR = 0.417, 95% CI = 0.417 ~ 0.838, p = 0.001). Results were consistent across sensitivity and subgroup analyses. CONCLUSION: In patients with diabetic AMI, in-hospital and continued use of DAPA after discharge were associated with a significant lower risk of heart failure rehospitalization.

A 3D culture system improves the yield of MSCs-derived extracellular vesicles and enhances their therapeutic efficacy for heart repair.

BACKGROUND: Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs), due to their inner functional substances, have shown great value in treating acute myocardial infarction (AMI). However, their clinical application is limited by a low yield. In the present study, we cultured EVs using a hollow fiber bioreactor-based three-dimensional (3D) system, and assessed their therapeutic effectiveness on AMI. METHODS: The MSCs separated from fresh human umbilical cord were planted into the flasks of two systems: two-dimensional (2D) culture and hollow-fiber-bioreactor based 3D culture. EVs were extracted from the culture supernatants. Characteristics and yields of EVs from two culture systems, namely 2D-EVs and 3D-EVs, were compared. A rat model of AMI was built up to assess their therapeutic efficacy on AMI. RESULTS: The yield of 3D-EVs was higher, with biofunctions similar to those of 2D-EVs. 3D-EVs repressed the apoptosis of cardiomyocytes, facilitated angiogenesis, and regulated the transition of macrophage subpopulations after myocardial infarction, and eventually improved cardiac function in the AMI rats. CONCLUSIONS: The hollow fiber 3D culture system can increase the yield of MSCs-derived EVs to render a strong cardioprotective effect in AMI rats.

A New Scoring System for Predicting Ventricular Arrhythmia Risk in Patients with Acute Myocardial Infarction.

Objective: In this study, a risk score for ventricular arrhythmias (VA) were evaluated for predicting the risk of ventricular arrhythmia (VA) of acute myocardial infarction (AMI) patients. Methods: Patients with AMI were divided into two sets according to whether VA occurred during hospitalization. Another cohort was enrolled for external validation. The area under the curve (AUC) of receiver operating characteristic (ROC) was calculated to evaluate the accuracy of the model. Results: A total of 1493 eligible patients with AMI were enrolled as the training set, of whom 70 (4.7%) developed VA during hospitalization. In-hospital mortality was significantly higher in the VA set than in the non-VA set (31.4% vs 2.7%, P=0.001). The independent predictors of VA in patients with AMI including Killip grade ≥3, STEMI patients, LVEF <50%, frequent premature ventricular beats, serum potassium <3.5 mmol/L, type 2 diabetes, and creatinine level. The AUC of the model for predicting VT/VF in the training set was 0.815 (95% CI: 0.763-0.866). A total of 1149 cases were enrolled from Xuzhou Center Hospital as the external validation set. The AUC of the model in the external validation set for predicting VT/VF was 0.755 (95% CI: 0.687-0.823). Calibration curves indicated a good consistency between the predicted and the observed probabilities of VA in both sets. Conclusion: We have established a clinical prediction risk score for predicting the occurrence of VA in AMI patients. The prediction score is easy to use, performs well and can be used to guide clinical practice.

Empagliflozin-Pretreated Mesenchymal Stem Cell-Derived Small Extracellular Vesicles Attenuated Heart Injury.

Objective: Small extracellular vesicles derived from mesenchymal stem cells (MSCs) play important roles in cardiac protection. Studies have shown that the cardiovascular protection of sodium-glucose cotransporter 2 inhibitor (SGLT2i) is independent of its hypoglycemic effect. This study is aimed at investigating whether small extracellular vesicles derived from MSCs pretreated with empagliflozin (EMPA) has a stronger cardioprotective function after myocardial infarction (MI) and to explore the underlying mechanisms. Methods and Results: We evaluated the effects of EMPA on MSCs and the effects of EMPA-pretreated MSCs-derived small extracellular vesicles (EMPA-sEV) on myocardial apoptosis, angiogenesis, and cardiac function after MI in vitro and in vivo. The small extracellular vesicles of control MSCs (MSC-sEV) and EMPA-pretreated MSCs were extracted, respectively. Small extracellular vesicles were cocultured with apoptotic H9c2 cells induced by H2O2 or injected into the infarcted area of the Sprague-Dawley (SD) rat myocardial infarction model. EMPA increased the cell viability, migration ability, and inhibited apoptosis and senescence of MSCs. In vitro, EMPA-sEV inhibited apoptosis of H9c2 cells compared with the control group (MSC-sEV). In the SD rat model of MI, EMPA-sEV inhibited myocardial apoptosis and promoted angiogenesis in the infarct marginal areas compared with the MSC-sEV. Meanwhile, EMPA-sEV reduced infarct size and improved cardiac function. Through small extracellular vesicles (miRNA) sequencing, we found several differentially expressed miRNAs, among which miR-214-3p was significantly elevated in EMPA-sEV. Coculture of miR-214-3p high expression MSC-derived small extracellular vesicles with H9c2 cells produced similar protective effects. In addition, miR-214-3p was found to promote AKT phosphorylation in H9c2 cells. Conclusions: Our data suggest that EMPA-sEV significantly improve cardiac repair after MI by inhibiting myocardial apoptosis. miR-214-3p at least partially mediated the myocardial protection of EMPA-sEV through the AKT signaling pathway.

[Effects of hemoglobin level on the risk of acute kidney injury in patients with acute myocardial infarction].

OBJECTIVE: To investigate the effect of preoperative hemoglobin (Hb) level on the risk of developing acute kidney injury (AKI) after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). METHODS: A retrospective study was conducted. The hospitalized patients diagnosed with AMI who underwent PCI from May 2015 to May 2020 in the department of cardiology in the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University were enrolled. According to the serum creatinine (SCr) level before and after interventional therapy, the patients were divided into an AKI group and a non-AKI group. The difference in patients' Hb levels between the AKI and non-AKI groups was compared. Univariate and multivariate Logistic regression analyses were used to analyze the effects of Hb levels on the risk of AKI after interventional therapy in patients with AMI. Kaplan-Meier survival curve was used to evaluate the effects of Hb levels on patients with AMI in all-cause death in the hospital. RESULTS: A total of 922 AMI patients were enrolled in this study, of which 165 patients (17.9%) developed AKI. Compared with the non-AKI group, female patients in the AKI group had a higher proportion [35.8% (59/165) vs. 26.9% (204/757)], older (age: 69.78±14.56 vs. 66.61±13.44), with a lower rate of smoking [42.4% (70/165) vs. 51.7% (391/757)] and a higher prevalence of hypertension [73.3% (121/165) vs. 63.5% (481/757)], however, the patients in AKI group also had a worse cardiac function [the proportion of Killip grade 3 or above was higher: 33.9% (56/165) vs. 13.9% (105/757)], lower Hb level (g/L: 127.61±22.18 vs. 132.79±19.45), and there were less patients using angiotensin converting enzyme inhibitor/angiotensin II receptor blocker [ACEI/ARB, 60.0% (99/165) vs. 74.5% (564/757)] and more patients using diuretics [24.8% (41/165) vs. 17.7% (134/757)] in AKI group, the differences were statistically significant (all P < 0.05). Compared with non-AKI group, patients in AKI group had a longer operation time [operation time > 60 minutes: 4.2% (7/165) vs. 1.5% (11/757)] and received more contrast media during the operative procedure [contrast media > 100 mL: 16.4% (27/165) vs. 3.6% (27/757)], the individuals had a higher rate of intra-operative hypotension [16.4% (27/165) vs. 8.2% (62/757)], and more patients were implanted more than 2 stents [8.5% (14/165) vs. 3.6% (27/757), all P < 0.05]. Univariate Logistic regression analysis suggested that each 1 g/L increase in preoperative Hb level was associated with a 1.2% decrease in the risk of postoperative AKI [odds ratio (OR) = 0.988, 95% confidence interval (95%CI) was 0.980-0.996, P = 0.003]. Meanwhile, for every 1 standard deviation increase in preoperative Hb level, the risk of postoperative AKI decreased by 22.1% (OR = 0.779, 95%CI was 0.661-0.918, P = 0.003). The patients were divided into low, medium and high concentration groups according to Hb levels (Hb levels were < 110 g/L, 110-150 g/L, ≥ 150 g/L, respectively), and multivariate Logistic regression analysis showed that the risk of AKI was significantly reduced in the high concentration group compared with that in the low concentration group (OR = 0.463, 95%CI was 0.241-0.888, P = 0.020). The Kaplan-Meier survival curve analysis indicated that the short term survival after coronary intervention in AMI patients with low Hb concentration was significantly lower than that in patients with medium and high Hb concentration (Log-Rank: χ2 = 23.215, P < 0.001). CONCLUSIONS: Preoperative lower Hb level is an independent risk factor for postoperative AKI in AMI patients. AMI patients with lower Hb levels have an increased risk of all-cause mortality within 1 month after AMI.

Predicting acute kidney injury risk in acute myocardial infarction patients: An artificial intelligence model using medical information mart for intensive care databases.

Background: Predictive models based on machine learning have been widely used in clinical practice. Patients with acute myocardial infarction (AMI) are prone to the risk of acute kidney injury (AKI), which results in a poor prognosis for the patient. The aim of this study was to develop a machine learning predictive model for the identification of AKI in AMI patients. Methods: Patients with AMI who had been registered in the Medical Information Mart for Intensive Care (MIMIC) III and IV database were enrolled. The primary outcome was the occurrence of AKI during hospitalization. We developed Random Forests (RF) model, Naive Bayes (NB) model, Support Vector Machine (SVM) model, eXtreme Gradient Boosting (xGBoost) model, Decision Trees (DT) model, and Logistic Regression (LR) models with AMI patients in MIMIC-IV database. The importance ranking of all variables was obtained by the SHapley Additive exPlanations (SHAP) method. AMI patients in MIMIC-III databases were used for model evaluation. The area under the receiver operating characteristic curve (AUC) was used to compare the performance of each model. Results: A total of 3,882 subjects with AMI were enrolled through screening of the MIMIC database, of which 1,098 patients (28.2%) developed AKI. We randomly assigned 70% of the patients in the MIMIC-IV data to the training cohort, which is used to develop models in the training cohort. The remaining 30% is allocated to the testing cohort. Meanwhile, MIMIC-III patient data performs the external validation function of the model. 3,882 patients and 37 predictors were included in the analysis for model construction. The top 5 predictors were serum creatinine, activated partial prothrombin time, blood glucose concentration, platelets, and atrial fibrillation, (SHAP values are 0.670, 0.444, 0.398, 0.389, and 0.381, respectively). In the testing cohort, using top 20 important features, the models of RF, NB, SVM, xGBoost, DT model, and LR obtained AUC of 0.733, 0.739, 0.687, 0.689, 0.663, and 0.677, respectively. Placing RF models of number of different variables on the external validation cohort yielded their AUC of 0.711, 0.754, 0.778, 0.781, and 0.777, respectively. Conclusion: Machine learning algorithms, particularly the random forest algorithm, have improved the accuracy of risk stratification for AKI in AMI patients and are applied to accurately identify the risk of AKI in AMI patients.

Association of plasma free triiodothyronine levels with contrast-induced acute kidney injury and short-term survival in patients with acute myocardial infarction.

Objective: Post-treatment contrast-induced acute kidney injury (CI-AKI) is associated with poor outcomes in patients with acute myocardial infarction (AMI). A lower free triiodothyronine (FT3) level predicts a poor prognosis of AMI patients. This study evaluated the effect of plasma FT3 level in predicting CI-AKI and short-term survival among AMI patients. Methods: Coronary arteriography or percutaneous coronary intervention was performed in patients with AMI. A 1:3 propensity score (PS) was used to match patients in the CI-AKI group and the non-CI-AKI group. Results: Of 1480 patients enrolled in the study, 224 (15.1%) patients developed CI-AKI. The FT3 level was lower in CI-AKI patients than in non-CI-AKI patients (3.72 ± 0.88 pmol/L vs 4.01 ± 0.80 pmol/L, P < 0.001). Compared with those at the lowest quartile of FT3, the patients at quartiles 2-4 had a higher risk of CI-AKI respectively (P for trend = 0.005). The risk of CI-AKI increased by 17.7% as FT3 level decreased by one unit after PS-matching analysis (odds ratio: 0.823; 95% CI: 0.685-0.988, P = 0.036). After a median of 31 days of follow-up (interquartile range: 30-35 days), 78 patients died, including 72 cardiogenic deaths and 6 non-cardiogenic deaths, with more deaths in the CI-AKI group than in the non-CI-AKI group (53 vs 25, P < 0.001). Kaplan-Meier survival analysis showed that patients at a lower FT3 quartile achieved a worse survival before and after matching. Conclusion: Lower FT3 may increase the risk of CI-AKI and 1-month mortality in AMI patients.

HIF-1α overexpression in mesenchymal stem cell-derived exosome-encapsulated arginine-glycine-aspartate (RGD) hydrogels boost therapeutic efficacy of cardiac repair after myocardial infarction.

AIMS: Naturally secreted extracellular vesicles (EVs) play important roles in stem-mediated cardioprotection. This study aimed to investigate the cardioprotective function and underlying mechanisms of EVs derived from HIF-1α engineered mesenchymal stem cells (MSCs) in a rat model of AMI. METHODS AND RESULTS: EVs isolated from HIF-1α engineered MSCs (HIF-1α-EVs) and control MSCs (NC-EVs) were prepared. In in vitro experiments, the EVs were incubated with cardiomyocytes and endothelial cells exposed to hypoxia and serum deprivation (H/SD); in in vivo experiments, the EVs were injected in the acutely infarcted hearts of Sprague-Dawley rats. Compared with NC-EVs, HIF-1α-EVs significantly inhibited the apoptosis of cardiomyocytes and enhanced angiogenesis of endothelial cells; meanwhile, HIF-1α-EVs also significantly shrunk fibrotic area and strengthened cardiac function in infarcted rats. After treatment with EVs/RGD-biotin hydrogels, we observed longer retention, higher stability in HIF-1α-EVs, and stronger cardiac function in the rats. Quantitative real-time PCR (qRT-PCR) displayed that miRNA-221-3p was highly expressed in HIF-1α-EVs. After miR-221-3p was inhibited in HIF-1α-EVs, the biological effects of HIF-1α EVs on apoptosis and angiogenesis were attenuated. CONCLUSION: EVs released by MSCs with HIF-1α overexpression can promote the angiogenesis of endothelial cells and the apoptosis of cardiomyocytes via upregulating the expression of miR-221-3p. RGD hydrogels can enhance the therapeutic efficacy of HIF-1α engineered MSCs-derived EVs.

[Development and validation of a clinical predictive model for the risk of malignant ventricular arrhythmia during hospitalization in patients with acute myocardial infarction].

OBJECTIVE: To develop and validate a clinical prediction model for the risk of malignant ventricular arrhythmia in patients with acute myocardial infarction (AMI) during hospitalization, and evaluate the effect of the prediction model. METHODS: A retrospective study was conducted. A total of 2 649 patients with AMI admitted to cardiology department of Changzhou No.2 People's Hospital of Nanjing Medical University from December 2012 to August 2020 were enrolled. The clinical characteristics including gender, age, medical history, discharge diagnosis, vital signs during hospitalization, electrocardiogram characteristics at admission, laboratory examination indexes, interventional treatment, drug usage, malignant ventricular arrhythmias [mainly included sustained ventricular tachycardia (VT), ventricular flutter or ventricular fibrillation (VF)], and death were recorded. All patients were divided into two groups according to whether VT/VF occurred during their hospitalization. Independent risk factors for VT/VF during hospitalization were evaluated by multivariate Logistic regression analysis, and a clinical prediction model was constructed. The receiver operating characteristic curve (ROC curve) was plotted, and the area under ROC curve (AUC) was calculated to evaluate the accuracy of the prediction model. RESULTS: A total of 2 649 eligible patients with AMI were enrolled, of whom 134 (5.06%) developed VT/VF during hospitalization. The in-hospital mortality rate in VT/VF group was significantly higher than that in non-VT/VF group (38.1% vs. 1.7%, P < 0.01). Compared with the non-VT/VF group, the patients in the VT/VF group with lower systolic blood pressure [SBP (mmHg, 1 mmHg = 0.133 kPa): 125.9±28.2 vs. 132.0±24.2], higher random blood glucose (mmol/L: 8.6±4.8 vs. 7.4±3.7), worse cardiac function [Killip heart function grade ≥ 3: 36.6% vs. 10.7%, left ventricular ejection fraction (LVEF) < 0.50: 56.7% vs. 33.6%, frequent premature ventricular contractions: 12.7% vs. 1.2%] and more hypokalemia (46.3% vs. 17.3%), with significant differences (all P < 0.05). Multivariate Logistic regression analysis showed that Killip classification of cardiac function ≥ 3 [odds ratio (OR) = 3.540, 95% confidence interval (95%CI) was 2.336-5.363], random blood glucose > 11.1 mmol/L (OR = 1.841, 95%CI was 1.171-2.893), LVEF < 0.50 (OR = 0.546, 95%CI was 0.374-0.797), frequent premature ventricular contractions (OR = 12.361, 95%CI was 6.077-25.144), potassium < 3.5 mmol/L (OR = 4.268, 95%CI was 2.910-6.259), SBP < 90 mmHg (OR = 0.299, 95%CI was 0.150-0.597) and creatinine (Cr) > 100 µmol/L (OR = 2.498, 95%CI was 1.170-5.334) were independent risk factors for VT/VF in patients with AMI (all P < 0.05). The clinical prediction model of VT/VF risk was constructed based on the variables selected by multivariate regression analysis. The ROC curve analysis showed that the AUC of the model in predicting VT/VF was 0.779 (95%CI was 0.735-0.823, P < 0.001); the optimal cut-off value of the model was 17, the sensitivity was 76.1%, the specificity was 67.3%. CONCLUSIONS: The incidence of VT/VF during hospitalization of AMI patients significantly increases the risk of in-hospital death. The independent risk factors of VT/VF are Killip grade ≥ 3, random blood glucose > 11.1 mmol/L, LVEF < 0.50, frequent ventricular premature beats, potassium < 3.5 mmol/L, SBP < 90 mmHg and Cr > 100 µmol/L. The newly constructed clinical prediction model has certain predictive value for the occurrence risk of VT/VF.