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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.

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

Poor viability of transplanted mesenchymal stem cells (MSCs) within the ischemic heart has limited their therapeutic potential for cardiac repair. We have previously shown that adiponectin (APN) treatment inhibits MSCs apoptosis under ischemic conditions in vitro. In this study, we investigated whether APN promoted the survival of MSCs in vivo and further contributed to cardiac repair in a rat model of acute myocardial infarction (AMI) by activating the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. Rats were randomized into six groups: the sham, AMI control, and four other groups that were subjected to AMI followed by treatment with MSCs, APN, APN + MSCs, and APN + MSCs + AMPK inhibitor, respectively. The engraftment and survival of MSCs were detected using both immunofluorescence staining and qPCR. Cardiac function was assessed using echocardiography and left heart catheterization. H&E staining and immunohistochemical staining for MHC-II and CD206 were performed to assess the infiltration of inflammatory cells. Immunostaining for the smooth muscle cell marker α-smooth-muscle actin (α-SMA) and endothelial cell marker CD31 was performed to assess arteriogenesis and angiogenesis. APN treatment significantly enhanced the engraftment and survival rate of transplanted MSCs and further improved cardiac function and led to reduced infarct size compared with MSCs treatment alone at 4 weeks after AMI. Combined administration of APN and MSCs noticeably suppressed the inflammatory response by specifically promoting the shift of infiltrated macrophages to an less-inflammatory phenotype. Combined administration of APN and MSCs also significantly inhibited cardiomyocyte apoptosis and increased arteriogenesis and angiogenesis in the peri-infarct myocardium compared with MSCs transplantation alone. These protective effects of APN were associated with AMPK phosphorylation and were partially reversed by AMPK pathway inhibitors. Our results are the first to show that APN is able to effectively improve the survival and therapeutic efficacy of transplanted MSCs after AMI through AMPK activation. APN has the potential to be utilized for stem cell-based heart repair after AMI.

ObjectiveTo 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).MethodsThis 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.ResultsAll 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 (pConclusionsIntensive 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 numberNCT00979758.

New Findings What is the central question of this study? In a rat model of acute myocardial infarction (AMI), we investigated the effect of Tongxinluo (TXL) treatment. Does TXL activate autophagy and attenuate apoptosis of cardiomyocytes through the AMPK pathway to facilitate survival of cardiomyocytes and improve cardiac function? What is the main finding and its importance? Major findings are as follows: (i) TXL treatment preserved cardiac function and reduced ventricular remodelling, infarct size and inflammation in rat hearts after AMI; (ii) TXL treatment dramatically increased autophagy and inhibited apoptosis in myocardium; and (iii) the AMPK signalling pathway played a crucial role in mediating the beneficial effects of TXL. Tongxinluo (TXL) has been demonstrated to have a protective role during ischaemia–reperfusion after acute myocardial infarction, but the long-term effects and underlying mechanisms are still unknown. The aim of this study was to investigate whether TXL could have an effect on apoptosis or autophagy of cardiomyocytes through the AMP-activated protein kinase (AMPK) pathway. Male Sprague–Dawley rats (n = 75) were randomly divided to sham, control, TXL (4 mg kg−1 day−1 orally), compound C (i.p. injection of 10 mg kg−1 day−1) and TXL + compound C groups. The extent of fibrosis, infarct size and angiogenesis were determined by pathological and histological studies. Four weeks after acute myocardial infarction, TXL treatment significantly increased ejection fraction, promoted angiogenesis in the peri-infarct region and substantially decreased fibrosis and the size of the infarcted area (P

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.

Background: Traditional Chinese medicine Tongxinluo (TXL) has been widely used to treat coronary artery disease in China, since it could reduce myocardial infarct size and ischemia/reperfusion injury in both non-diabetic and diabetic conditions. It has been shown that TXL could regulate peroxisome proliferator activated receptor-α (PPAR-α), a positive modulator of angiopoietin-like 4 (Angptl4), in diabetic rats. Endothelial junction substructure components, such as VE-cadherin, are involved in the protection of reperfusion injury. Thus, we hypothesized cell-intrinsic and endothelial-specific Angptl4 mediated the protection of TXL on endothelial barrier under high glucose condition against ischemia/reperfusion-injury via PPAR-α pathway. Methods: Incubated with high glucose medium, the human cardiac microvascular endothelial cells (HCMECs) were then exposed to oxygen-glucose-serum deprivation (2 hours) and restoration (2 hours) stimulation, with or without TXL, insulin, or rhAngptl4 pretreatment. Results: TXL, insulin, and rhAngptl4 had similar protective effects on the endothelial barrier. TXL treatment reversed the endothelial barrier breakdown in HCMECs significantly as identified by decreasing endothelial permeability, upregulating the expression of JAM-A, VE-cadherin, and integrin-α5 and increasing the membrane location of VE-cadherin and integrin-α5, and these effects of TXL were as effective as insulin and rhAngptl4. However, Angptl4 knock-down with small interfering RNA (siRNA) interference and PPAR-α inhibitor MK886 partially abrogated these beneficial effects of TXL. Western blotting also revealed that similar with insulin, TXL upregulated the expression of Angptl4 in HCMECs, which could be inhibited by Angptl4 siRNA or MK886 exposure. TXL treatment increased PPAR-α activity, which could be diminished by MK886 but not by Angptl4 siRNA. Conclusion: These data suggest cell-intrinsic and endothelial-specific Angptl4 mediates the protection of TXL against endothelial barrier breakdown during oxygen-glucose-serum deprivation and restoration under high glucose condition partly via the PPAR-α/Angptl4 pathway.

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.

By inhibiting apolipoprotein B (ApoB) synthesis, mipomersen can significantly reduce ApoB-containing lipoproteins in hypercholesterolemic patients. This study sought to ascertain both the extent to which mipomersen can decrease ApoB-containing lipoproteins and the safety of mipomersen therapy. Studies were identified through PubMed, CENTRAL, Embase, Clinical Trials, reviews, and reference lists of relevant papers. The efficacy endpoints were the changes in low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), ApoB, and lipoprotein (a) [Lp(a)]. The safety endpoints were the incidence of injection-site reactions, flu-like symptoms, and elevated transaminases. Six randomized controlled trials with 444 patients were included in the analysis. Compared with the placebo group, patients who received mipomersen therapy had a significant reduction in LDL-C (33.13 %), as well as a reduction in non-HDL-C (31.70 %), ApoB (33.27 %), and LP(a) (26.34 %). Mipomersen therapy was also associated with an obvious increase in injection-site reactions with an odds ratio (OR) of 14.15, flu-like symptoms with an OR of 2.07, and alanine aminotransferase levels ≥3 × the upper limit of normal with an OR of 11.21. Mipomersen therapy is effective for lowering ApoB-containing lipoproteins in patients with severe hypercholesterolemia. Future studies exploring how to minimize side effects of mipomersen therapy are needed.

What is the central question of this study? In a rat model of acute myocardial infarction (AMI), we investigated the effect of Tongxinluo (TXL) treatment. Does TXL activate autophagy and attenuate apoptosis of cardiomyocytes through the AMPK pathway to facilitate survival of cardiomyocytes and improve cardiac function? What is the main finding and its importance? Major findings are as follows: (i) TXL treatment preserved cardiac function and reduced ventricular remodelling, infarct size and inflammation in rat hearts after AMI; (ii) TXL treatment dramatically increased autophagy and inhibited apoptosis in myocardium; and (iii) the AMPK signalling pathway played a crucial role in mediating the beneficial effects of TXL. Tongxinluo (TXL) has been demonstrated to have a protective role during ischaemia-reperfusion after acute myocardial infarction, but the long-term effects and underlying mechanisms are still unknown. The aim of this study was to investigate whether TXL could have an effect on apoptosis or autophagy of cardiomyocytes through the AMP-activated protein kinase (AMPK) pathway. Male Sprague-Dawley rats (n = 75) were randomly divided to sham, control, TXL (4 mg kg

Stem cell therapy is a promising approach to the treatment of ischemic heart disease via replenishing cell loss after myocardial infarction. Both preclinical studies and clinical trials have indicated that cardiac function improved consistently, but very modestly after cell-based therapy. This mainly attributed to low cell survival rate, engraftment and functional integration, which became the major challenges to regenerative medicine. In recent years, several new cell types have been developed to regenerate cardiomyocytes and novel delivery approaches helped to increase local cell retention. New strategies, such as cell pretreatment, gene-based therapy, tissue engineering, extracellular vesicles application and immunologic regulation, have surged and brought about improved cell survival and functional integration leading to better therapeutic effects after cell transplantation. In this review, we summarize these new strategies targeting at challenges of cardiac regenerative medicine and discuss recent evidences that may hint their effectiveness in the future clinical settings.

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.

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

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.