Interleukin-5-induced eosinophil population improves cardiac function after myocardial infarction.

AIMS: Interleukin (IL)-5 mediates the development of eosinophils (EOS) that are essential for tissue post-injury repair. It remains unknown whether IL-5 plays a role in heart repair after myocardial infarction (MI). This study aims to test whether IL-5-induced EOS population promotes the healing and repair process post-MI and to reveal the underlying mechanisms. METHODS AND RESULTS: MI was induced by permanent ligation of the left anterior descending coronary artery in wild-type C57BL/6 mice. Western blot and real-time polymerase chain reaction revealed elevated expression of IL-5 in the heart at 5 days post-MI. Immunohistostaining indicated that IL-5 was secreted mainly from macrophages and CD127+ cells in the setting of experimental MI. External supply of recombinant mouse IL-5 (20 min, 1 day, and 2 days after MI surgery) reduced the infarct size and increased ejection fraction and angiogenesis in the border zone. A significant expansion of EOS was detected in both the peripheral blood and infarcted myocardium after IL-5 administration. Pharmacological depletion of EOS by TRFK5 pretreatment muted the beneficial effects of IL-5 in MI mice. Mechanistic studies demonstrated that IL-5 increased the accumulation of CD206+ macrophages in infarcted myocardium at 7 days post-MI. In vitro co-culture experiments showed that EOS shifted bone marrow-derived macrophage polarization towards the CD206+ phenotypes. This activity of EOS was abolished by IL-4 neutralizing antibody, but not IL-10 or IL-13 neutralization. Western blot analyses demonstrated that EOS promoted the macrophage downstream signal transducer and activator of transcription 6 (STAT6) phosphorylation. CONCLUSION: IL-5 facilitates the recovery of cardiac dysfunction post-MI by promoting EOS accumulation and subsequent CD206+ macrophage polarization via the IL-4/STAT6 axis.

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.

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.

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.

Optimization of Timing and Times for Administration of Atorvastatin-Pretreated Mesenchymal Stem Cells in a Preclinical Model of Acute Myocardial Infarction.

Our previous studies showed that the combination of atorvastatin (ATV) and single injection of ATV-pretreated mesenchymal stem cells (MSCs) (ATV -MSCs) at 1 week post-acute myocardial infarction (AMI) promoted MSC recruitment and survival. This study aimed to investigate whether the combinatorial therapy of intensive ATV with multiple injections of ATV -MSCs has greater efficacy at different stages to better define the optimal strategy for MSC therapy in AMI. In order to determine the optimal time window for MSC treatment, we first assessed stromal cell-derived factor-1 (SDF-1) dynamic expression and inflammation. Next, we compared MSC recruitment and differentiation, cardiac function, infarct size, and angiogenesis among animal groups with single, dual, and triple injections of ATV -MSCs at early (Early1, Early2, Early3), mid-term (Mid1, Mid2, Mid3), and late (Late1, Late2, Late3) stages. Compared with AMI control, intensive ATV significantly augmented SDF-1 expression 1.5∼2.6-fold in peri-infarcted region with inhibited inflammation. ATV -MSCs implantation with ATV administration further enhanced MSC recruitment rate by 3.9%∼24.0%, improved left ventricular ejection fraction (LVEF) by 2.0%∼16.2%, and reduced infarct size in all groups 6 weeks post-AMI with most prominent improvement in mid groups and still effective in late groups. Mechanistically, ATV -MSCs remarkably suppressed inflammation and apoptosis while increasing angiogenesis. Furthermore, triple injections of ATV -MSCs were much more effective than single administration during early and mid-term stages of AMI with the best effects in Mid3 group. We conclude that the optimal strategy is multiple injections of ATV -MSCs combined with intensive ATV administration at mid-term stage of AMI. The translational potential of this strategy is clinically promising. Stem Cells Translational Medicine 2019;8:1068-1083.

Inhibition of miR-128-3p by Tongxinluo Protects Human Cardiomyocytes from Ischemia/reperfusion Injury via Upregulation of p70s6k1/p-p70s6k1.

Background and Aims: Tongxinluo (TXL) is a multifunctional traditional Chinese medicine that has been widely used to treat cardiovascular and cerebrovascular diseases. However, no studies have explored whether TXL can protect human cardiomyocytes (HCMs) from ischemia/reperfusion (I/R) injury. Reperfusion Injury Salvage Kinase (RISK) pathway activation was previously demonstrated to protect the hearts against I/R injury and it is generally activated via Akt or (and) Erk 1/2, and their common downstream protein, ribosomal protein S6 kinase (p70s6k). In addition, prior studies proved that TXL treatment of cells promoted secretion of VEGF, which could be stimulated by the increased phosphorylation of one p70s6k subtype, p70s6k1. Consequently, we hypothesized TXL could protect HCMs from I/R injury by activating p70s6k1 and investigated the underlying mechanism. Methods and Results: HCMs were exposed to hypoxia (18 h) and reoxygenation (2 h) (H/R), with or without TXL pretreatment. H/R reduced mitochondrial membrane potential, increased bax/bcl-2 ratios and cytochrome C levels and induced HCM apoptosis. TXL preconditioning reversed these H/R-induced changes in a dose-dependent manner and was most effective at 400 µg/mL. The anti-apoptotic effect of TXL was abrogated by rapamycin, an inhibitor of p70s6k. However, inhibitors of Erk1/2 (U0126) or Akt (LY294002) failed to inhibit the protective effect of TXL. TXL increased p70s6k1 expression and, thus, enhanced its phosphorylation. Furthermore, transfection of cardiomyocytes with siRNA to p70s6k1 abolished the protective effects of TXL. Among the micro-RNAs (miR-145-5p, miR-128-3p and miR-497-5p) previously reported to target p70s6k1, TXL downregulated miR-128-3p in HCMs during H/R, but had no effects on miR-145-5p and miR-497-5p. An in vivo study confirmed the role of the p70s6k1 pathway in the infarct-sparing effect of TXL, demonstrating that TXL decreased miR-128-3p levels in the rat myocardium during I/R. Transfection of HCMs with a hsa-miR-128-3p mimic eliminated the protective effects of TXL. Conclusions: The miR-128-3p/p70s6k1 signaling pathway is involved in protection by TXL against HCM apoptosis during H/R. Overexpression of p70s6k1 is, therefore, a potential new strategy for alleviating myocardial reperfusion injury.

Quantitative Proteomics Analysis of Ischemia/Reperfusion Injury-Modulated Proteins in Cardiac Microvascular Endothelial Cells and the Protective Role of Tongxinluo.

BACKGROUND: The protection of endothelial cells (ECs) against reperfusion injury has received little attention. In this study, we used Tandem Mass Tag (TMT) labeling proteomics to investigate the modulated proteins in an in vitro model of cardiac microvascular endothelial cells (CMECs) subjected to ischemia/reperfusion (I/R) injury and their alteration by traditional Chinese medicine Tongxinluo (TXL). METHODS: Human CMECs were subjected to 2 h of hypoxia followed by 2 h of reoxygenation with different concentrations of TXL Protein expression profiles of CMECs were determined using tandem mass spectrometry. We evaluated several proteins with altered expression in I/R injury and summarized some reported proteins related to I/R injury. RESULTS: TXL dose-dependently decreased CMEC apoptosis, and the optimal concentration was 800 µg/mL. I/R significantly altered proteins in CMECs, and 30 different proteins were detected between a normal group and a hypoxia and serum deprivation group. In I/R injury, TXL treatment up-regulated 6 types of proteins including acyl-coenzyme A synthetase ACSM2B mitochondrial (ACSM2B), cyclin-dependent kinase inhibitor 1B (CDKN1B), heme oxygenase 1 (HMOX1), transcription factor SOX-17 (SOX17), sequestosome-1 isoform 1 (SQSTM1), and TBC1 domain family member 10B (TBC1D10B). Also, TXL down-regulated 5 proteins including angiopoietin-2 isoform c precursor (ANGPT2), cytochrome c oxidase assembly factor 5 (COA5), connective tissue growth factor precursor (CTGF), cathepsin L1 isoform 2 (CTSL), and eukaryotic elongation factor 2 kinase (LOC101930123). These types of proteins mainly had vital functions, including cell proliferation, stress response, and regulation of metabolic process. CONCLUSIONS: The study presented differential proteins upon I/R injury through a proteomic analysis. TXL modulated the expression of proteins in CMECs and has a protective role in response to I/R.

AMPK-mediated cardioprotection of atorvastatin relates to the reduction of apoptosis and activation of autophagy in infarcted rat hearts.

Atorvastatin (ATV) has an important pro-survival role in cardiomyocytes after acute myocardial infarction (AMI). The objectives of this study were to: 1) determine whether ATV could affect autophagy of cardiomyocytes via the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, and 2) investigate the balance between autophagy and apoptosis pathways. Male Wistar rats (n = 100) were randomly divided into sham, control, ATV, Compound C, and ATV+ Compound C groups. In this AMI model, drug treatments were administered for 1 week before induction of MI by surgical ligation, and measurements were taken 1 and 4 weeks after AMI induction. Transthoracic echocardiography showed that the ejection fraction in the ATV group increased by 11.7% ± 6.83% over the control group 4 weeks after AMI. The fibrosis, infarcted area, and inflammatory level were determined by pathological and histological studies; these were found to be decreased substantially with ATV treatment (P<0.05). The expression of apoptotic, autophagic, and AMPK pathway proteins was detected by immunohistochemical staining and western blotting, while expression of their corresponding genes was measured with real-time polymerase chain reaction (PCR). ATV treatment increased AMPK/mTOR activity and the expression of autophagic protein LC3 in infarcted myocardium (P<0.05). The treatment also inhibited induction of pro-apoptotic protein Bax. AMPK inhibitor Compound C reversed these beneficial effects. In conclusion, ATV improves survival of cardiomyocytes and decreases alterations in morphology and function of infarcted hearts by inducing autophagy and inhibiting apoptosis through the activation of AMPK/mTOR pathway.

Globular Adiponectin Inhibits the Apoptosis of Mesenchymal Stem Cells Induced by Hypoxia and Serum Deprivation via the AdipoR1-Mediated Pathway.

BACKGROUND/AIMS: Poor viability of transplanted mesenchymal stem cells (MSCs) within the ischemic heart limits their therapeutic potential for cardiac repair. Globular adiponectin (gAPN) exerts anti-apoptotic effects on several types of stem cells. Herein, we investigated the effect of gAPN on the MSCs against apoptosis induced by hypoxia and serum deprivation (H/SD). METHODS: MSCs exposed to H/SD conditions were treated with different concentrations of gAPN. To identify the main type of receptor, MSCs were transfected with siRNA targeting adiponectin receptor 1 or 2 (AdipoR1 or AdipoR2). To elucidate the downstream pathway, MSCs were pre-incubated with AMPK inhibitor Compound C. Apoptosis, caspase-3 activity and mitochondrial membrane potential were evaluated. RESULTS: H/SD-induced MSCs apoptosis and caspase-3 activation were attenuated by gAPN in a concentration-dependent manner. gAPN increased Bcl-2 and decreased Bax expressions. The loss of mitochondrial membrane potential induced by H/SD was also abolished by gAPN. The protective effect of gAPN was significantly attenuated after the knockdown of AdipoR1 rather than AdipoR2. Moreover, Compound C partly suppressed the anti-apoptotic effect of gAPN. CONCLUSIONS: gAPN inhibits H/SD-induced apoptosis in MSCs via AdipoR1-mediated pathway, possibly linked to the activation of AMPK. gAPN may be a novel survival factor for MSCs in the ischemic engraftment environment.