Atorvastatin-pretreated mesenchymal stem cell-derived extracellular vesicles promote cardiac repair after myocardial infarction via shifting macrophage polarization by targeting microRNA-139-3p/Stat1 pathway.

BACKGROUND: Extracellular vesicles (EVs) derived from bone marrow mesenchymal stem cells (MSCs) pretreated with atorvastatin (ATV) (MSCATV-EV) have a superior cardiac repair effect on acute myocardial infarction (AMI). The mechanisms, however, have not been fully elucidated. This study aims to explore whether inflammation alleviation of infarct region via macrophage polarization plays a key role in the efficacy of MSCATV-EV. METHODS: MSCATV-EV or MSC-EV were intramyocardially injected 30 min after coronary ligation in AMI rats. Macrophage infiltration and polarization (day 3), cardiac function (days 0, 3, 7, 28), and infarct size (day 28) were measured. EV small RNA sequencing and bioinformatics analysis were conducted for differentially expressed miRNAs between MSCATV-EV and MSC-EV. Macrophages were isolated from rat bone marrow for molecular mechanism analysis. miRNA mimics or inhibitors were transfected into EVs or macrophages to analyze its effects on macrophage polarization and cardiac repair in vitro and in vivo. RESULTS: MSCATV-EV significantly reduced the amount of CD68+ total macrophages and increased CD206+ M2 macrophages of infarct zone on day 3 after AMI compared with MSC-EV group (P < 0.01-0.0001). On day 28, MSCATV-EV much more significantly improved the cardiac function than MSC-EV with the infarct size markedly reduced (P < 0.05-0.0001). In vitro, MSCATV-EV also significantly reduced the protein and mRNA expressions of M1 markers but increased those of M2 markers in lipopolysaccharide-treated macrophages (P < 0.05-0.0001). EV miR-139-3p was identified as a potential cardiac repair factor mediating macrophage polarization. Knockdown of miR-139-3p in MSCATV-EV significantly attenuated while overexpression of it in MSC-EV enhanced the effect on promoting M2 polarization by suppressing downstream signal transducer and activator of transcription 1 (Stat1). Furthermore, MSCATV-EV loaded with miR-139-3p inhibitors decreased while MSC-EV loaded with miR-139-3p mimics increased the expressions of M2 markers and cardioprotective efficacy. CONCLUSIONS: We uncovered a novel mechanism that MSCATV-EV remarkably facilitate cardiac repair in AMI by promoting macrophage polarization via miR-139-3p/Stat1 pathway, which has the great potential for clinical translation.

Worsening of Renal Function Among Hospitalized Patients With Acute Heart Failure: Phenotyping, Outcomes, and Predictors.

OBJECTIVE: To define clinical phenotyping and its associated outcome of worsening of renal function (WRF) in hospitalized acute heart failure (AHF) patients. PATIENTS AND METHODS: Latent class analysis was performed in 113 AHF patients who developed WRF within 72 hours in the DOSE (Diuretic Optimization Strategies Evaluation) trial (from March 2008 to November 2009) and ROSE-AHF (Renal Optimization Strategies Evaluation in Acute Heart Failure) trial (from September 2010 to March 2013) to identify potential WRF phenotypes. Clinical characteristics and outcome (in-hospital and post-discharge) were compared between different phenotypes. RESULTS: Two WRF phenotypes were identified by latent class analysis, which we named WRF minimally responsive to diuretics (WRF-MRD) and WRF responsive to diuretics (WRF-RD). Among the population, 58 (9.5%) developed WRF-MRD and 55 (9.0%) developed WRF-RD. Patients with WRF-MRD had more comorbidities than WRF-RD. In WRF-MRD, there were an early increase in serum creatinine, a smaller amount of net fluid loss and weight loss, and a higher rate of worsening or persistent heart failure over 72 hours. In contrast, for those with WRF-RD, they had faster in-hospital net fluid loss and weight loss and a better 60-day survival after discharge even compared with patients without WRF (P=.004). Furthermore, baseline chronic obstructive pulmonary disease, diabetes, and cystatin C were independent predictors of WRF-MRD, whereas serum hemoglobin and sodium predicted WRF-RD. CONCLUSIONS: Among hospitalized AHF patients, we identified two phenotypes of WRF with distinct response to heart failure treatment, predictors, and short-term prognosis after discharge. The results could help early differentiation of WRF phenotypes in clinical practice.

Salt restriction and risk of adverse outcomes in heart failure with preserved ejection fraction.

BACKGROUND: The optimal salt restriction in patients with heart failure (HF), especially patients with heart failure with preserved ejection fraction (HFpEF), remains controversial. OBJECTIVE: To investigate the associations of cooking salt restriction with risks of clinical outcomes in patients with HFpEF. METHODS: Cox proportional hazards model and subdistribution hazards model were used in this secondary analysis in 1713 participants with HFpEF from the Americas in the TOPCAT trial. Cooking salt score was the sum of self-reported salt added during homemade food preparation. The primary endpoint was a composite of cardiovascular death, HF hospitalisation and aborted cardiac arrest, and secondary outcomes were all-cause death, cardiovascular death and HF hospitalisation. RESULTS: Compared with patients with cooking salt score 0, patients with cooking salt score >0 had significantly lower risks of the primary endpoint (HR=0.760, 95% CI 0.638 to 0.906, p=0.002) and HF hospitalisation (HR=0.737, 95% CI 0.603 to 0.900, p=0.003), but not all-cause (HR=0.838, 95% CI 0.684 to 1.027, p=0.088) or cardiovascular death (HR=0.782, 95% CI 0.598 to 1.020, p=0.071). Sensitivity analyses using propensity score matching baseline characteristics and in patients who prepared meals mostly at home yielded similar results. Subgroup analysis suggested that the association between overstrict salt restriction and poor outcomes was more predominant in patients aged ≤70 years and of non-white race. CONCLUSION: Overstrict cooking salt intake restriction was associated with worse prognosis in patients with HFpEF, and the association seemed to be more predominant in younger and non-white patients. Clinicians should be prudent when giving salt restriction advice to patients with HFpEF.

Tongxinluo-pretreated mesenchymal stem cells facilitate cardiac repair via exosomal transfer of miR-146a-5p targeting IRAK1/NF-κB p65 pathway.

BACKGROUND: Bone marrow cells (BMCs), especially mesenchymal stem cells (MSCs), have shown attractive application prospects in acute myocardial infarction (AMI). However, the weak efficacy becomes their main limitation in clinical translation. Based on the anti-inflammation and anti-apoptosis effects of a Chinese medicine-Tongxinluo (TXL), we aimed to explore the effects of TXL-pretreated MSCs (MSCsTXL) in enhancing cardiac repair and further investigated the underlying mechanism. METHODS: MSCsTXL or MSCs and the derived exosomes (MSCsTXL-exo or MSCs-exo) were collected and injected into the infarct zone of rat hearts. In vivo, the anti-apoptotic and anti-inflammation effects, and cardiac functional and histological recovery were evaluated. In vitro, the apoptosis was evaluated by western blotting and flow cytometry. miRNA sequencing was utilized to identify the significant differentially expressed miRNAs between MSCsTXL-exo and MSCs-exo, and the miRNA mimics and inhibitors were applied to explore the specific mechanism. RESULTS: Compared to MSCs, MSCsTXL enhanced cardiac repair with reduced cardiomyocytes apoptosis and inflammation at the early stage of AMI and significantly improved left ventricular ejection fraction (LVEF) with reduced infarct size in an exosome-dependent way. Similarly, MSCsTXL-exo exerted superior therapeutic effects in anti-apoptosis and anti-inflammation, as well as improving LVEF and reducing infarct size compared to MSCs-exo. Further exosomal miRNA analysis demonstrated that miR-146a-5p was the candidate effector of the superior effects of MSCsTXL-exo. Besides, miR-146a-5p targeted and decreased IRAK1, which inhibited the nuclear translocation of NF-κB p65 thus protecting H9C2 cells from hypoxia injury. CONCLUSIONS: This study suggested that MSCsTXL markedly facilitated cardiac repair via a new mechanism of the exosomal transfer of miR-146a-5p targeting IRAK1/NF-κB p65 pathway, which has great potential for clinical translation.

Systematic error analysis and parameter design of a vision-based phase estimation method for ultra-precision positioning.

Ultra-precision position measurement is increasingly important in advanced manufacturing such as the semiconductor industry and fiber optics or photonics. A vision-based phase estimation method we proposed previously performs position measurement by imaging a 2D periodic pattern. In this paper, systematic errors of this method are analyzed and derived mathematically, which are classified into two types: spectrum leakage error caused by image truncation and window function modulation, and sub-pixel error resulting from discrete Fourier transform (DFT) intensity interpolation. Key design parameters are concluded including pattern period T, camera pixel size t and resolution N, as well as the type of window function used. Numerical simulations are conducted to investigate the relationship between the phase errors and design parameters. Then an error reduction method is proposed. Finally, the improved performance of parameter optimization is validated by a comparative experiment. Experimental results show the measurement errors of the prototype are within ∼2 nm in X or Y axis, and ∼1 µrad in axis, which reaches the sub-pixel accuracy better than 10-3pixel.

Modified Exosomes: a Good Transporter for miRNAs within Stem Cells to Treat Ischemic Heart Disease.

Stem cell-based therapy for ischemic heart disease (IHD) has become a promising but controversial strategy during the past two decades. The fate and effects of stem cells engrafted into ischemia myocardium are still not fully understood. Stem cell-derived exosomes, a subcategory of extracellular vesicles with nano size, have been considered as an efficient and safe transporter for microRNAs (miRNAs) and a central mediator of the cardioprotective potentials of the parental cells. Hypoxia, pharmacological intervention, and gene manipulation could alter the exosomal miRNAs cargos from stem cells and promote therapeutic potential. Furthermore, several bioengineering methods were also successfully applied to modify miRNAs content and components of exosomal membrane proteins recently. In this review, we outline relevant results about exosomal miRNAs from stem cells and focus on the current strategies to promote their therapeutic efficiency in IHD.

Sequential transplantation of exosomes and mesenchymal stem cells pretreated with a combination of hypoxia and Tongxinluo efficiently facilitates cardiac repair.

BACKGROUND: Bone marrow-derived mesenchymal stem cells (MSCs), which possess immunomodulatory characteristic, are promising candidates for the treatment of acute myocardial infarction (AMI). However, the low retention and survival rate of MSCs in the ischemic heart limit their therapeutic efficacy. Strategies either modifying MSCs or alleviating the inflammatory environment, which facilitates the recruitment and survival of the engrafted MSCs, may solve the problem. Thus, we aimed to explore the therapeutic efficacy of sequential transplantation of exosomes and combinatorial pretreated MSCs in the treatment of AMI. METHODS: Exosomes derived from MSCs were delivered to infarcted hearts through intramyocardial injection followed by the intravenous infusion of differentially pretreated MSCs on Day 3 post-AMI. Enzyme linked immunosorbent assay (ELISA) was performed to evaluate the inflammation level as well as the SDF-1 levels in the infarcted border zone of the heart. Echocardiography and histological analysis were performed to assess cardiac function, infarct size, collagen area and angiogenesis. RESULTS: Sequential transplantation of exosomes and the combinatorial pretreated MSCs significantly facilitated cardiac repair compared to AMI rats treated with exosomes alone. Notably, compared to the other three methods of cotransplantation, combinatorial pretreatment with hypoxia and Tongxinluo (TXL) markedly enhanced the CXCR4 level of MSCs and promoted recruitment, which resulted in better cardiac function, smaller infarct size and enhanced angiogenesis. We further demonstrated that exosomes effectively reduced apoptosis in MSCs in vitro. CONCLUSION: Sequential delivery of exosomes and pretreated MSCs facilitated cardiac repair post-AMI, and combined pretreatment with hypoxia and TXL better enhanced the cardioprotective effects. This method provides new insight into the clinical translation of stem cell-based therapy for AMI.

Associations of BMI with mortality in HFpEF patients with concomitant diabetes with insulin versus non-insulin treatment.

BACKGROUND: Obesity confers paradoxical survival benefits in heart failure with preserved ejection fraction (HFpEF). The purpose of this study was to examine the impact of DM and insulin treatment status on the associations of body mass index (BMI) with the death risks in HFpEF patients. METHODS: HFpEF patients from the TOPCAT trial were included. Cox regression model was constructed to assess the relationship of BMI with the risks of all-cause death and cardiovascular death. Restricted cubic splines were used to characterize the dose-response associations of BMI with risks of death. RESULTS: Compared with normal weight, hazard ratios of all-cause death in overweight and class I obesity were 0.62 (0.45-0.85), 0.67 (0.47-0.94) in no DM HFpEF patients, and 0.48 (0.25-0.91), 0.41 (0.22-0.79) in non-insulin-treated DM patients. However, insulin treatment removed this beneficial effect. Consistent results were found when modeling for time-updated BMI. Cubic spline analyses suggested a linear trend of increased death risk with higher BMI in insulin-treated DM patients. CONCLUSIONS: The "obesity paradox" was present in HFpEF patients without DM or with non-insulin-treated DM but absent in those with insulin-treated DM. Insulin treatment may be a crucial confounder of the obesity paradox in HFpEF patients. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov. Unique identifier: NCT00094302.

Association of Body-Weight Fluctuation With Outcomes in Heart Failure With Preserved Ejection Fraction.

Aims: To investigate the relationship between body-weight fluctuation and risks of clinical outcomes in patients with heart failure with preserved ejection fraction (HFpEF). Methods and Results:We measured intra-individual variations in body weight from baseline and follow-up visits in 1,691 participants with HFpEF from the Americas from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial. The primary endpoint was any cardiovascular events (a composite of death from cardiovascular disease, non-fatal myocardial infarction, aborted cardiac arrest, or hospitalization for HF). The body-weight fluctuation was measured according to average successive variability and high variability was defined as greater than or equal to the median. After adjustment for risk factors, mean body weight and weight change, each increase of 1 standard deviation in body-weight variability was significantly associated with increased risks of any cardiovascular events (hazard ratio [HR] 1.23, 95% confidence interval [CI] 1.15-1.33, P < 0.001). Patients with high variability had a 47% increased risk of any cardiovascular events and 27% increased risk of all-cause death compared with those with low variability. Such association was similar among patients with New York Heart Association functional class I/II vs. III/IV, obesity vs. non-obesity, and weight loss, gain vs. stability (the P-values for interaction were all insignificant). Conclusion: Among patients with HFpEF, body-weight fluctuation was associated with increased risks of cardiovascular events independent of traditional cardiovascular risk factors, and regardless of HF severity, baseline weight or weight change direction. Clinical Trial Registration: Aldosterone antagonist therapy for adults with heart failure and preserved systolic function (TOPCAT), https://clinicaltrials.gov, identifier [NCT00094302].

Weight Change and Mortality Risk in Heart Failure With Preserved Ejection Fraction.

Aims: The aim of the study was to determine the associations of weight loss or gain with all-cause mortality risk in heart failure with preserved ejection fraction (HFpEF). Methods and Results: Non-lean patients from the Americas from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist study were analyzed (n = 1,515). Weight loss and weight gain were defined as a decrease or increase in weight ≥5% between baseline and 1 year. To determine the associations of weight change and mortality risk, we used adjusted Cox proportional hazards models and restricted cubic spline models. The mean age was 71.5 (9.6) years. Weight loss and gain were witnessed in 19.3 and 15.9% patients, respectively. After multivariable adjustment, weight loss was associated with higher risk of mortality (HR 1.42, 95% CI 1.06-1.89, P = 0.002); weight gain had similar risk of mortality (HR 0.98, 95% CI 0.68-1.42, P = 0.932) compared with weight stability. There was linear relationship between weight change and mortality risk. The association of weight loss and mortality was different for patients with and without diabetes mellitus (interaction p = 0.009). Conclusion: Among patients with HFpEF, weight loss was independently associated with higher risk of all-cause mortality, and weight gain was not associated with better survival. Clinical Trial Registration: https://clinicaltrials.gov, Identifier: NCT00094302.

Association of long-term SBP with clinical outcomes and quality of life in heart failure with preserved ejection fraction: an analysis of the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist trial.

AIMS: To determine the associations of long-term SBP (LT-SBP) levels with clinical outcomes and health-related quality of life in heart failure with preserved ejection fraction (HFpEF). METHODS AND RESULTS: We analyzed participants from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) study with available different SBP measurements from different follow-ups (n = 3310). LT-SBP was the mean SBP value from 4-week measurement to the last one. The outcome measures are all-cause mortality and a composite of heart failure readmission or all-cause mortality and the Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary score. To determine the associations of LT-SBP and outcomes, we used adjusted Cox proportional hazards models and restricted cubic spline models. After multivariable adjustment, LT-SBP of 120-129 and 130-139 mmHg were associated with a lower risk of mortality (hazard ratio 0.66, 95% CI 0.51-0.87, P = 0.003; hazard ratio 0.68, 95% CI 0.51-0.90, P = 0.007, respectively); LT-SBP of 100-119 mmHg had similar risk of mortality (hazard ratio 0.96, 95% CI 0.72-1.28, P = 0.778) compared with LT-SBP of at least 140 mmHg. There was U-shaped relationship between LT-SBP and all-cause mortality (P < 0.001) with nadir risk occurring around 123 mmHg. Similar relationships were observed between LT-SBP and composite end point of heart failure readmission or all-cause mortality. The adjusted mean improvement in KCCQ score was significantly higher in the 120-129 mmHg group than in the at least 140 mmHg group beginning from the 12-month follow-up visit without significant differences in other groups. CONCLUSION: Among patients with HFpEF, long-term control of SBP level at 120-129 mmHg is independently associated with the highest risk reduction of all-cause mortality and improvement of KCCQ score. Future randomized clinical trials need to specifically evaluate optimal SBP treatment goals in patients with HFpEF.

Down-regulation of Beclin1 promotes direct cardiac reprogramming.

Direct reprogramming of fibroblasts to alternative cell fates by forced expression of transcription factors offers a platform to explore fundamental molecular events governing cell fate identity. The discovery and study of induced cardiomyocytes (iCMs) not only provides alternative therapeutic strategies for heart disease but also sheds lights on basic biology underlying CM fate determination. The iCM field has primarily focused on early transcriptome and epigenome repatterning, whereas little is known about how reprogramming iCMs remodel, erase, and exit the initial fibroblast lineage to acquire final cell identity. Here, we show that autophagy-related 5 (Atg5)-dependent autophagy, an evolutionarily conserved self-digestion process, was induced and required for iCM reprogramming. Unexpectedly, the autophagic factor Beclin1 (Becn1) was found to suppress iCM induction in an autophagy-independent manner. Depletion of Becn1 resulted in improved iCM induction from both murine and human fibroblasts. In a mouse genetic model, Becn1 haploinsufficiency further enhanced reprogramming factor-mediated heart function recovery and scar size reduction after myocardial infarction. Mechanistically, loss of Becn1 up-regulated Lef1 and down-regulated Wnt inhibitors, leading to activation of the canonical Wnt/ß-catenin signaling pathway. In addition, Becn1 physically interacts with other classical class III phosphatidylinositol 3-kinase (PI3K III) complex components, the knockdown of which phenocopied Becn1 depletion in cardiac reprogramming. Collectively, our study revealed an inductive role of Atg5-dependent autophagy as well as a previously unrecognized autophagy-independent inhibitory function of Becn1 in iCM reprogramming.

Cardiomyocyte-derived small extracellular vesicles can signal eNOS activation in cardiac microvascular endothelial cells to protect against Ischemia/Reperfusion injury.

Rationale: The crosstalk between cardiac microvascular endothelial cells (CMECs) and cardiomyocytes (CMs) has emerged as a key component in the development of, and protection against, cardiac diseases. For example, activation of endothelial nitric oxide synthase (eNOS) in CMECs, by therapeutic strategies such as ischemic preconditioning, plays a critical role in the protection against myocardial ischemia/reperfusion (I/R) injury. However, much less is known about the signals produced by CMs that are able to regulate CMEC biology. Here we uncovered one such mechanism using Tongxinluo (TXL), a traditional Chinese medicine, that alleviates myocardial ischemia/reperfusion (I/R) injury by activating CMEC eNOS. The aim of our study is to identify the signals produced by CMs that can regulate CMEC biology during I/R. Methods:Ex vivo, in vivo, and in vitro settings of ischemia-reperfusion were used in our study, with the protective signaling pathways activated in CMECs identified using genetic inhibition (p70s6k1 siRNA, miR-145-5p mimics, etc.), chemical inhibitors (the eNOS inhibitor, L-NNA, and the small extracellular vesicles (sEVs) inhibitor, GW4869) and Western blot analyses. TritonX-100 at a dose of 0.125% was utilized to inactivate the eNOS activity in endothelium to investigate the role of CMEC-derived eNOS in TXL-induced cardioprotection. Results: We found that while CMEC-derived eNOS activity was required for the cardioprotection of TXL, activation of eNOS in CMECs by TXL did not occur directly. Instead, eNOS activation in CMECs required a crosstalk between CMs and CMECs through the uptake of CM-derived sEVs. We further demonstrate that TXL induced CM-sEVs contain increased levels of Long Intergenic Non-Protein Coding RNA, Regulator Of Reprogramming (Linc-ROR). Upon uptake into CMECs, linc-ROR downregulates its target miR-145-5p leading to activation of the eNOS pathway by facilitating the expression of p70s6k1 in these cells. The activation of CMEC-derived eNOS works to increase survival in both the CMECs and the CMs themselves. Conclusions: These data uncover a mechanism by which the crosstalk between CMs and CMECs leads to the increased survival of the heart after I/R injury and point to a new therapeutic target for the blunting of myocardial I/R injury.

Strengthening effects of bone marrow mononuclear cells with intensive atorvastatin in acute myocardial infarction.

OBJECTIVE: To test whether intensive atorvastatin (ATV) increases the efficacy of transplantation with autologous bone marrow mononuclear cells (MNCs) in patients suffering from anterior ST-elevated myocardial infarction (STEMI). METHODS: This clinical trial was under a 2×2 factorial design, enrolling 100 STEMI patients, randomly into four groups of regular (RA) or intensive ATV (IA) with MNCs or placebo. The primary endpoint was the change of left ventricular ejection fraction (LVEF) at 1-year follow-up from baseline, primarily assessed by MRI. The secondary endpoints included other parameters of cardiac function, remodelling and regeneration determined by MRI, echocardiography, positron emission tomography (PET) and biomarkers. RESULTS: All the STEMI patients with transplantation of MNCs showed significantly increased LVEF change values than those with placebo (p=0.01) with only in the IA+MNCs patients group demonstrating significantly elevation of LVEF than in the IA+placebo group (+12.6% (95%CI 10.4 to 19.3) vs +5.0% (95%CI 4.0 to 10.0), p=0.001), pointing to a better synergy between ATV and MNCs (p=0.019). PET analysis revealed significantly increased viable areas of myocardium (p=0.015), while the scar sizes (p=0.026) and blood aminoterminal pro-B-type natriuretic peptide (p<0.034) reduced. All these above benefits of MNCs were also attributed to IA+MNCs instead of RA+MNCs group of patients with STEMI. CONCLUSIONS: Intensive ATV treatment augments the therapeutic efficacy of MNCs in patients with anterior STEMI at the convalescent stage. The treatment with the protocol of intensive ATV and MNC combination offers a clinically essential approach for myocardial infarction. TRIAL REGISTRATION NUMBER: NCT00979758.

Isoform Specific Effects of Mef2C during Direct Cardiac Reprogramming.

Direct conversion of cardiac fibroblasts into induced cardiomyocytes (iCMs) by forced expression of defined factors holds great potential for regenerative medicine by offering an alternative strategy for treatment of heart disease. Successful iCM conversion can be achieved by minimally using three transcription factors, Mef2c (M), Gata4(G), and Tbx5 (T). Despite increasing interest in iCM mechanistic studies using MGT(polycistronic construct with optimal expression of M,G and T), the reprogramming efficiency varies among different laboratories. Two main Mef2c isoforms (isoform2, Mi2 and isoform4, Mi4) are present in heart and are used separately by different labs, for iCM reprogramming. It is currently unknown if differently spliced isoform of Mef2c contributes to varied reprogramming efficiency. Here, we used Mi2 and Mi4 together with Gata4 and Tbx5 in separate vectors or polycistronic vector, to convert fibroblasts to iCMs. We found that Mi2 can induce higher reprogramming efficiency than Mi4 in MEFs. Addition of Hand2 to MGT retroviral cocktail or polycistronic Mi2-GT retroviruses further enhanced the iCM conversion. Overall, this study demonstrated the isoform specific effects of Mef2c, during iCM reprogramming, clarified some discrepancy about varied efficiency among labs and might lead to future research into the role of alternative splicing and the consequent variants in cell fate determination.

Role of Exosomal miRNAs in Heart Failure.

Heart failure is the terminal outcome of the majority of cardiovascular diseases, which lacks specific diagnostic biomarkers and therapeutic targets. It contributes to most of cardiovascular hospitalizations and death despite of the current therapy. Therefore, it is important to explore potential molecules improving the diagnosis and treatment of heart failure. MicroRNAs (miRNAs) are small non-coding RNAs that have been reported to be involved in regulating processes of heart failure. After the discovery of miRNAs in exosomes, the subcellular distribution analysis of miRNAs is raising researchers' attention. Growing evidence demonstrates that exosomal miRNAs may be promising diagnostic and therapeutic molecules for heart failure. This review summarizes the role of exosomal miRNAs in heart failure in the prospect of molecular and clinical researches.

Atorvastatin enhances the therapeutic efficacy of mesenchymal stem cells-derived exosomes in acute myocardial infarction via up-regulating long non-coding RNA H19.

AIMS: Naturally secreted nanovesicles, known as exosomes, play important roles in stem cell-mediated cardioprotection. We have previously demonstrated that atorvastatin (ATV) pretreatment improved the cardioprotective effects of mesenchymal stem cells (MSCs) in a rat model of acute myocardial infarction (AMI). The aim of this study was to investigate if exosomes derived from ATV-pretreated MSCs exhibit more potent cardioprotective function in a rat model of AMI and if so to explore the underlying mechanisms. METHODS AND RESULTS: Exosomes were isolated from control MSCs (MSC-Exo) and ATV-pretreated MSCs (MSCATV-Exo) and were then delivered to endothelial cells and cardiomyocytes in vitro under hypoxia and serum deprivation (H/SD) condition or in vivo in an acutely infarcted Sprague-Dawley rat heart. Regulatory genes and pathways activated by ATV pretreatment were explored using genomics approaches and functional studies. In vitro, MSCATV-Exo accelerated migration, tube-like structure formation, and increased survival of endothelial cells but not cardiomyocytes, whereas the exosomes derived from MSCATV-Exo-treated endothelial cells prevented cardiomyocytes from H/SD-induced apoptosis. In a rat AMI model, MSCATV-Exo resulted in improved recovery in cardiac function, further reduction in infarct size and reduced cardiomyocyte apoptosis compared to MSC-Exo. In addition, MSCATV-Exo promoted angiogenesis and inhibited the elevation of IL-6 and TNF-α in the peri-infarct region. Mechanistically, we identified lncRNA H19 as a mediator of the role of MSCATV-Exo in regulating expression of miR-675 and activation of proangiogenic factor VEGF and intercellular adhesion molecule-1. Consistently, the cardioprotective effects of MSCATV-Exo was abrogated when lncRNA H19 was depleted in the ATV-pretreated MSCs and was mimicked by overexpression of lncRNA H19. CONCLUSION: Exosomes obtained from ATV-pretreated MSCs have significantly enhanced therapeutic efficacy for treatment of AMI possibly through promoting endothelial cell function. LncRNA H19 mediates, at least partially, the cardioprotective roles of MSCATV-Exo in promoting angiogenesis.

Transplantation efficacy of autologous bone marrow mesenchymal stem cells combined with atorvastatin for acute myocardial infarction (TEAM-AMI): rationale and design of a randomized, double-blind, placebo-controlled, multi-center, Phase II TEAM-AMI trial.

Aim: To determine the efficacy and safety of intracoronary infusion of autologous bone marrow mesenchymal stem cells (MSCINJ) in combination with intensive atorvastatin (ATV) treatment for patients with anterior ST-segment elevation myocardial infarction-elevation myocardial infarction. Patients & methods: The trial enrolls a total of 100 patients with anterior ST-elevation myocardial infarction. The subjects are randomly assigned (1:1:1:1) to receive routine ATV (20 mg/d) with placebo or MSCsINJ and intensive ATV (80 mg/d) with placebo or MSCsINJ. The primary end point is the absolute change of left ventricular ejection fraction within 12 months. The secondary end points include parameters in cardiac function, remodeling and regeneration, quality of life, biomarkers and clinical outcomes. Results & conclusion: The trial will implicate the essential of cardiac micro-environment improvement ('fertilizing') for cell-based therapy. Clinical Trial Registration: NCT03047772.

Combinatorial treatment of acute myocardial infarction using stem cells and their derived exosomes resulted in improved heart performance.

BACKGROUND: Bone marrow mesenchymal stem cells (MSCs) are among the most common cell types to be used and studied for cardiac regeneration. Low survival rate and difficult retention of delivered MSCs in infarcted heart remain as major challenges in the field. Co-delivery of stem cell-derived exosomes (Exo) is expected to improve the recruitment and survival of transplanted MSCs. METHODS: Exo was isolated from MSCs and delivered to an acute myocardial infarction (AMI) rat heart through intramyocardial injection with or without intravenous infusion of atrovastatin-pretreated MSCs on day 1, day 3, or day 7 after infarction. Echocardiography was performed to evaluate cardiac function. Histological analysis and ELISA test were performed to assess angiogenesis, SDF-1, and inflammatory factor expression in the infarct border zone. The anti-apoptosis effect of Exo on MSCs was evaluated using flow cytometry and Hoechst 33342 staining assay. RESULTS: We found that intramyocardial delivery of Exo followed by MSC transplantation (in brief, Exo+MSC treatment) into MI hearts further improved cardiac function, reduced infarct size, and increased neovascularization when compared to controls treated with Exo or MSCs alone. Of note, comparing the three co-transplanting groups, intramyocardially injecting Exo 30 min after AMI combined with MSCs transplantation at day 3 after AMI achieved the highest improvement in heart function. The observed enhanced heart function is likely due to an improved microenvironment via Exo injection, which is exemplified as reduced inflammatory responses and better MSC recruitment and retention. Furthermore, we demonstrated that pre-transplantation injection of Exo enhanced survival of MSCs and reduced their apoptosis both in vitro and in vivo. CONCLUSIONS: Combinatorial delivery of exosomes and stem cells in a sequential manner effectively reduces scar size and restores heart function after AMI. This approach may represent as an alternative promising strategy for stem cell-based heart repair and therapy.

Combined therapy with atorvastatin and atorvastatin-pretreated mesenchymal stem cells enhances cardiac performance after acute myocardial infarction by activating SDF-1/CXCR4 axis.

The SDF-1/CXCR4 signaling plays a critical role in the trafficking of mesenchymal stem cells (MSCs) to the sites of tissue damage. Our recent study demonstrated that atorvastatin (ATV) treatment improved the survival of MSCs, and ATV pretreated MSCs (ATV-MSCs) exhibited enhanced engraftment to injured myocardium. In this study, we investigated whether combined treatment with ATV and ATV-MSCs enhances cardiac repair and regeneration by activating SDF-1/CXCR4 signaling in a rat model of acute myocardial infarction. Rats were randomized into eight groups: the Sham, AMI control and 6 other groups that were subjected to AMI followed by treatment with MSCs, ATV, ATV+MSCs, ATV-MSCs, ATV+ATV-MSCs, ATV+ATV-MSCs+AMD3100 (SDF-1/CXCR4 antagonist), respectively. ATV+ATV-MSCs significantly potentiated targeted recruitment of MSCs to peri-infarct myocardium and resulted in further improvements in cardiac function and reduction in scar size compared with MSCs treatment alone at 4-week after AMI. More importantly, the cardioprotective effects conferred by ATV+ATV-MSCs were almost completely abolished by AMD3100 treatment. Together, our study demonstrated that ATV+ATV-MSCs significantly enhanced the targeted recruitment and survival of transplanted MSCs, and resulted in subsequent cardiac function improvement by augmenting SDF-1/CXCR4 signaling.