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Abstract Background Cardiac lipoma, a seldom-encountered benign tumor positioned beneath the endocardium, has the potential to impair electrophysiological functions. Diagnosis is principally based on imaging modalities. The uniqueness of this case lies in the tumor’s extension both internally and externally within the right atrium, rendering it of special interest. From a clinical standpoint, surgical removal is commonly advocated, wherein early intervention is pivotal in improving patients’ long-term prognoses. Case presentation A 35-year-old male was admitted to the hospital for treatment subsequent to the identification of a cardiac mass two days prior. Initial diagnostic assessments, encompassing CT scans and echocardiography, identified a space-occupying lesion within the heart. The patient underwent surgical excision of the cardiac tumor, utilizing mild hypothermic extracorporeal circulation via femoral vessel access. Intraoperative findings revealed adipose-like tissue of a “dumbbell-shaped” configuration situated both within and external to the right atrium, measuring approximately 8 cm*9 cm internally and 7 cm*6 cm externally, with the extracardiac mass being marginally larger. Postoperative pathological analysis confirmed a cardiac lipoma diagnosis. A follow-up echocardiogram conducted three months post-surgery exhibited no notable abnormalities. The patient is under continuous observation to monitor for any recurrence or potential long-term complications. Conclusion In this case report, we detail with precision a rare cardiac pathology manifested by an expansive infiltrative lipoma that pervades the endocardial and epicardial layers of the right atrium. After thorough preoperative diagnostic workup and evaluation, we contend that surgical intervention represents the optimal therapeutic approach for managing such conditions, with the goal of preemptively reducing the likelihood of cardiac compression or intracardiac obstruction.

BackgroundThoracic Aortic Dissection (TAD) is a life-threatening disease without effective drug treatments. The disruption of HASMCs homeostasis is one direct histopathologic alteration in TAD pathological process. Several miRNAs have been shown abnormally expressed in TAD and to regulate HASMCs homeostasis. The primary goal of this study is to identify the miRNAs and the specific mechanisms that lead to HASMCs homeostasis disruption.MethodsBulk miRNA sequencing was performed to explore the aberrantly expressed miRNA profile in TAD, and differentially expressed miRNAs were verified with qRT-PCR. To explore the role of the key miRNAs (miR-3529) in HASMCs homeostasis, we overexpressed this miRNA with lentivirus in HASMCs. Integrative transcriptomics and metabolomics analysis were used to uncover the functional roles of this miRNA in regulating HASMCs homeostasis. Further, the target gene of miR-3529 was predicted by bioinformatics and verified through a dual-luciferase reporter assay.ResultsBulk miRNA sequencing showed miR-3529 was elevated in TAD tissues and confirmed by qRT-PCR. Further experimental assay revealed miR-3529 upregulation induced HASMCs homeostasis disruption, accompanied by reducing contractile markers and increasing pro-inflammatory cytokines. Integrative transcriptomics and metabolomics analysis showed that miR-3529 overexpression altered the metabolic profile of HASMC, particularly lipid metabolism. ABCA1 was found to be a direct target of miR-3529. Mechanistically, the miR-3529/ABCA1 axis disrupted HASMCs homeostasis through the JAK2/STAT3 signaling pathway.ConclusionsmiR-3529 is elevated in TAD patients and disrupts HASMCs homeostasis by reprogramming metabolism through the JAK2/STAT3 signaling pathway. These findings favor a role for miR-3529 as a novel target for TAD therapy.

Abstract During spaceflight, the cardiovascular system undergoes remarkable adaptation to microgravity and faces the risk of cardiac remodeling. Therefore, the effects and mechanisms of microgravity on cardiac morphology, physiology, metabolism, and cellular biology need to be further investigated. Since China started constructing the China Space Station (CSS) in 2021, we have taken advantage of the Shenzhou-13 capsule to send human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) to the Tianhe core module of the CSS. In this study, hPSC-CMs subjected to space microgravity showed decreased beating rate and abnormal intracellular calcium cycling. Metabolomic and transcriptomic analyses revealed a battery of metabolic remodeling of hPSC-CMs in spaceflight, especially thiamine metabolism. The microgravity condition blocked the thiamine intake in hPSC-CMs. The decline of thiamine utilization under microgravity or by its antagonistic analog amprolium affected the process of the tricarboxylic acid cycle. It decreased ATP production, which led to cytoskeletal remodeling and calcium homeostasis imbalance in hPSC-CMs. More importantly, in vitro and in vivo studies suggest that thiamine supplementation could reverse the adaptive changes induced by simulated microgravity. This study represents the first astrobiological study on the China Space Station and lays a solid foundation for further aerospace biomedical research. These data indicate that intervention of thiamine-modified metabolic reprogramming in human cardiomyocytes during spaceflight might be a feasible countermeasure against microgravity.

Abstract Background SARS-CoV-2, the pathogen of COVID-19, is a worldwide threat to human health and causes a long-term burden on the cardiovascular system. Individuals with pre-existing cardiovascular diseases are at higher risk for SARS-CoV-2 infection and tend to have a worse prognosis. However, the relevance and pathogenic mechanisms between COVID-19 and cardiovascular diseases are not yet completely comprehended. Methods Common differentially expressed genes (DEGs) were obtained in datasets of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) infected with SARS-CoV-2 and myocardial tissues from heart failure patients. Further GO and KEGG pathway analysis, protein–protein interaction (PPI) network construction, hub genes identification, immune microenvironment analysis, and drug candidate predication were performed. Then, an isoproterenol-stimulated myocardial hypertrophy cell model and a transverse aortic constriction-induced mouse heart failure model were employed to validate the expression of hub genes. Results A total of 315 up-regulated and 78 down-regulated common DEGs were identified. Functional enrichment analysis revealed mitochondrial metabolic disorders and extensive immune inflammation as the most prominent shared features of COVID-19 and cardiovascular diseases. Then, hub DEGs, as well as hub immune-related and mitochondria-related DEGs, were screened. Additionally, nine potential therapeutic agents for COVID-19-related cardiovascular diseases were proposed. Furthermore, the expression patterns of most of the hub genes related to cardiovascular diseases in the validation dataset along with cellular and mouse myocardial damage models, were consistent with the findings of bioinformatics analysis. Conclusions The study unveiled the molecular networks and signaling pathways connecting COVID-19 and cardiovascular diseases, which may provide novel targets for intervention of COVID-19-related cardiovascular diseases.

Abstract Mesenchymal stromal/stem cells (MSCs) have emerged as a promising approach against myocardial infarction. Due to hostile hyperinflammation, however, poor retention of transplanted cells seriously impedes their clinical applications. Proinflammatory M1 macrophages, which rely on glycolysis as their main energy source, aggravate hyperinflammatory response and cardiac injury in ischemic region. Here, we showed that the administration of an inhibitor of glycolysis, 2‐deoxy‐d‐glucose (2‐DG), blocked the hyperinflammatory response within the ischemic myocardium and subsequently extended effective retention of transplanted MSCs. Mechanistically, 2‐DG blocked the proinflammatory polarization of macrophages and suppressed the production of inflammatory cytokines. Selective macrophage depletion abrogated this curative effect. Finally, to avoid potential organ toxicity caused by systemic inhibition of glycolysis, we developed a novel chitosan/gelatin‐based 2‐DG patch that directly adhered to the infarcted region and facilitated MSC‐mediated cardiac healing with undetectable side effects. This study pioneered the application of an immunometabolic patch in MSC‐based therapy and provided insights into the therapeutic mechanism and advantages of this innovative biomaterial.

Abstract Background Endothelial cells are located in the inner lumen of blood and lymphatic vessels and exhibit the capacity to form new vessel branches from existing vessels through a process called angiogenesis. This process is energy intensive and tightly regulated. Glycolysis is the main energy source for angiogenesis. Retinoic acid (RA) is an active metabolite of vitamin A and exerts biological effects through its receptor retinoic acid receptor (RAR). In the clinic, RA is used to treat acne vulgaris and acute promyelocytic leukemia. Emerging evidence suggests that RA is involved in the formation of the vasculature; however, its effect on endothelial cell angiogenesis and metabolism is unclear. Methods Our study was designed to clarify the abovementioned effect with human embryonic stem cell-derived endothelial cells (hESC-ECs) employed as a cell model. Results We found that RA inhibits angiogenesis, as manifested by decreased proliferation, migration and sprouting activity. RNA sequencing revealed general suppression of glycometabolism in hESC-ECs in response to RA, consistent with the decreased glycolytic activity and glucose uptake. After screening glycometabolism-related genes, we found that fructose-1,6-bisphosphatase 1 (FBP1), a key rate-limiting enzyme in gluconeogenesis, was significantly upregulated after RA treatment. After silencing or pharmacological inhibition of FBP1 in hESC-ECs, the capacity for angiogenesis was enhanced, and the inhibitory effect of RA was reversed. ChIP-PCR demonstrated that FBP1 is a target gene of RAR. When hESC-ECs were treated with the RAR inhibitor BMS493, FBP1 expression was decreased and the effect of RA on angiogenesis was partially blocked. Conclusions The inhibitory role of RA in glycometabolism and angiogenesis is RAR/FBP1 dependent, and FBP1 may be a novel therapeutic target for pathological angiogenesis.

Bone marrow stem cell (BMSC) transplantation during coronary artery bypass graft (CABG) is an innovative treatment for ischemic heart disease (IHD). We conduct a meta-analysis to examine whether patients with IHD presenting heart failure with reduced ejection fraction (HFrEF) can be beneficent from CABG with additional BMSC transplantation. Electronic searches were performed on PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov from their inception to July 2021. The efficacy was based on left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left ventricular end-diastolic volume (LVEDV), left ventricular end-diastolic volume index (LVEDVi), left ventricular end-systolic volume index (LVESVi), and 6-min walk test (6MWT) change after treatment. Eight randomized-controlled trials (RCTs) were included in this meta-analysis, with a total of 350 patients. Results showed BMSC transplantation significantly improved the LVEF [mean difference (MD) = 6.23%, 95% confidence interval (CI): 3.22%–9.24%, P < 0.0001], LVEDVi (MD = −20.15 ml/m 2 , 95% CI: −30.49 to −9.82 ml/m 2 , P < 0.00001), and LVESVi (MD = −17.69 ml/m 2 , 95% CI: −25.24 to −10.14 ml/m 2 , P < 0.00001). There was no statistically significant difference in the improvement of LVEDD, LVEDV, and 6MWT between the cell transplantation group and control groups. Subgroup analysis revealed that the intervention for control group could affect the efficacy of BMSC transplantation. Sensitivity analysis found the conclusion of LVEDD, LVEDV, and 6MWT changes was not stable. Therefore, among patients with IHD presenting HFrEF, BMSC transplantation during CABG is promising to be beneficial for postoperative left ventricular (LV) function improvement. However, according to the unstable results of the sensitivity analysis, it cannot be concluded whether the extra step has a positive effect on left ventricular remodeling and exercise capacity. RCTs with larger cohorts and more strict protocols are needed to validate these conclusions.

Objective. Myocardial infarction is a leading cause of mortality worldwide. Angiogenesis in the infarct border zone is vital for heart function restoration after myocardial infarction. Hypoxia-induced MSC modification is a safe and effective approach for angiogenesis in clinical therapy; however, the mechanism still requires further investigation. In our study, we preconditioned human umbilical cord mesenchymal stem cells (huMSCs) with hypoxia and isolated the small extracellular vesicles (sEVs) to promote cardiac repair. We also investigated the potential mechanisms. Method. huMSCs were preconditioned with hypoxia (1% O2 and 5% CO2 at 37°C for 48 hours), and their sEVs were isolated using the Total Exosome Isolation reagent kit. To explore the role of miR-214 in MSC-derived sEVs, sEVs with low miR-214 expression were prepared by transfecting miR-214 inhibitor into huMSCs before hypoxia pretreatment. Scratch assays and tube formation assays were performed in sEVs cocultured with HUVECs to assess the proangiogenic capability of MSC-sEVs and MSChyp-sEVs. Rat myocardial infarction models were used to investigate the ability of miR-214-differentially expressed sEVs in cardiac repair. Echocardiography, Masson’s staining, and immunohistochemical staining for CD31 were performed to assess cardiac function, the ratio of myocardial fibrosis, and the capillary density after sEV implantation. The potential mechanism by which MSChyp-sEVs enhance angiogenesis was explored in vitro by RT–qPCR and western blotting. Results. Tube formation and scratch assays demonstrated that the proangiogenic capability of huMSC-derived sEVs was enhanced by hypoxia pretreatment. Echocardiography and Masson’s staining showed greater improvements in heart function and less ventricular remodeling after MSChyp-sEV transplantation. The angiogenic capability was reduced following miR-214 knockdown in MSChyp-sEVs. Furthermore, Sufu, a target of miR-214, was decreased, and hedgehog signaling was activated in HUVECs. Conclusion. We found that hypoxia induced miR-214 expression both in huMSCs and their sEVs. Transplantation of MSChyp-sEVs into a myocardial infarction model improved cardiac repair by increasing angiogenesis. Mechanistically, MSChyp-sEVs promote HUVEC tube formation and migration by transferring miR-214 into recipient cells, inhibiting Sufu expression, and activating the hedgehog pathway. Hypoxia-induced vesicle modification is a feasible way to restore heart function after myocardial infarction.

Background and aimsSurgical site infection is a common complication after surgery. Periprocedural antibiotics are necessary to prescribe for preventing or treating infections. The present study aimed to explore the effect of intravenous antibiotics on gut microbiota and menaquinone biosynthesis in patients, especially in elderly patients undergoing cardiac surgery.MethodsA total of 388 fecal samples were collected from 154 cardiac surgery patients. The V3–V4 hypervariable region of the bacterial 16S rRNA gene was amplified and sequenced on a MiSeq PE300. The gut microbiota diversity of samples was analyzed in terms of α- and β-diversity at the OTU level. The different groups were classified according to antibiotics in combinations and single antibiotics. PICRUSt2 was used for preliminary prediction of the gut microbiota function for menaquinone biosynthesis.ResultsThe intravenously administered antibiotics which are excreted via bile represents the main antibiotics that could disturb the gut microbiota’s composition in cardiac surgery patients, especially for elderly patients. The effect of antibiotics on gut microbiota is produced after antibiotics treatments over one week. The recovery of gut microbiota to the state of pre-antibiotics may require over two weeks of antibiotics withdrawal. Sex factor doesn’t represent as an influencer in gut microbiota composition. Long-term use of cefoperazone-sulbactam may affect coagulation function.ConclusionsThe composition of the gut microbiota had a significant change post-intravenous antibiotics treatment in cardiac surgery patients. The richness and diversity of gut microbiota are increased in elderly patients.

BMP10 signaling has been implicated in regulation of cardiovascular cell fate determination and diseases, while the underlying molecular mechanism still remains uncertain. Here, the human embryonic stem cell line (H7-BMP10del) with homozygous deletion of BMP10 was generated by CRISPR/Cas9 method. Thus, the crosstalk related to BMP10 signaling could be investigated in cell fate determination and the molecular pathogenesis of cardiovascular disease.

Abstract Inflammasomes are protein complexes of the innate immune system that initiate inflammation in response to either exogenous pathogens or endogenous danger signals. Inflammasome multiprotein complexes are composed of three parts: a sensor protein, an adaptor, and pro-caspase-1. Activation of the inflammasome leads to the activation of caspase-1, which cleaves pro-inflammatory cytokines such as IL-1β and IL-18, leading to pyroptosis. Effectors of the inflammasome not only provide protection against infectious pathogens, but also mediate control over sterile insults. Aberrant inflammasome signaling has been implicated in the development of cardiovascular and metabolic diseases, cancer, and neurodegenerative disorders. Here, we review the role of the inflammasome as a double-edged sword in various diseases, and the outcomes can be either good or bad depending on the disease, as well as the genetic background. We highlight inflammasome memory and the two-shot activation process. We also propose the M- and N-type inflammation model, and discuss how the inflammasome pathway may be targeted for the development of novel therapy.

Thoracic aortic dissection is a devastating cardiovascular disease with an increasing annual incidence. The homozygous mutation in rs1801133 site has been accepted for decreased enzyme activity of mutant MTHFR protein, contributing to an accumulated homocysteine in blood. Recently, elevated homocysteine level is causally associated with an increased risk of cardiovascular disease. Conversely, the relationship between rs1801133 and thoracic aortic dissection is poorly understood. Here, the generated human induced pluripotent stem cell (iPSC) line provided a novel strategy for investigating the underlying mechanism of MTHFR mutation (rs1801133, TT) and its implication in the pathogenesis of thoracic aortic dissection.

Myocardial infarction (MI) is one of cardiovascular diseases that pose a serious threat to human health. The pathophysiology of MI is complex and contains several sequential phases including blockage of a coronary artery, necrosis of myocardial cells, inflammation, and myocardial fibrosis. Aiming at the treatment of different stages of MI, in this work, an injectable alginate based composite hydrogel is developed to load vascular endothelial active factor (VEGF) and silk fibroin (SF) microspheres containing bone morphogenetic protein 9 (BMP9) for releasing VEGF and BMP9 to realize their respective functions. The results of in vitro experiments indicate a rapid initial release of VEGF during the first few days and a relatively slow and sustained release of BMP9 for days, facilitating the formation of blood vessels in the early stage and inhibiting myocardial fibrosis in the long-term stage, respectively. Intramyocardial injection of such composite hydrogel into the infarct border zone of mice MI model via multiple points promotes angiogenesis and reduces the infarction size. Taken together, these results indicate that the dual-release of VEGF and BMP9 from the composite hydrogel results in a collaborative effect on the treatment of MI and improvement of heart function, showing a promising potential for cardiac clinical application.

Marfan syndrome (MFS) is an autosomal genetic disorder caused by mutation in FBN1 gene, encoding the extracellular matrix protein fibrillin-1. Here, a MFS patient specific iPSC carrying a novel heterozygous mutation (c.7897 T > G) in FBN1 gene was generated. This iPSC line exhibited normal morphology and karyotype, and could differentiate into three germ layers in vivo and in vitro. Thus, the established iPSC line provided a precise platform for elucidating the molecular pathogenesis and personalized drug screening of MFS.

Abstract Background Myocardial infarction (MI) is a severe disease that often associated with dysfunction of angiogenesis. Cell-based therapies for MI using mesenchymal stem cell (MSC)-derived exosomes have been well studied due to their strong proangiogenic effect. Genetic modification is one of the most common methods to enhance exosome therapy. This study investigated the proangiogenic and cardioprotective effect of exosomes derived from hypoxia-inducible factor 1-alpha (HIF-1α)-modified MSCs. Methods Lentivirus containing HIF-1α overexpressing vector was packaged and used to infect MSCs. Exosomes were isolated from MSC-conditioned medium by ultracentrifugation. Human umbilical vein endothelial cells (HUVECs) were treated under hypoxia condition for 48 h co-cultured with PBS, control exosomes, or HIF-1α-overexpressed exosomes, respectively. Then the preconditioned HUVECs were subjected to tube formation assay, Transwell assay, and EdU assay to evaluate the protective effect of exosomes. Meanwhile, mRNA and secretion levels of proangiogenic factors were measured by RT-qPCR and ELISA assays. In vivo assays were conducted using the rat myocardial infarction model. PBS, control exosomes, or HIF-1α-overexpressed exosomes were injected through tail vein after MI surgery. Heart function was assessed by echocardiography at days 3, 14, and 28. At day 7, mRNA and protein expression levels of proangiogenic factors in the peri-infarction area and circulation were evaluated, respectively. At day 28, hearts were collected and subjected to H&E staining, Masson’s trichrome staining, and immunofluorescent staining. Results HIF-1α-overexpressed exosomes rescued the impaired angiogenic ability, migratory function, and proliferation of hypoxia-injured HUVECs. Simultaneously, HIF-1α-overexpressed exosomes preserved heart function by promoting neovessel formation and inhibiting fibrosis in the rat MI model. In addition, both in vitro and in vivo proangiogenic factors mRNA and protein expression levels were elevated after HIF-1α-overexpressed exosome application. Conclusion HIF-1α-overexpressed exosomes could rescue the impaired angiogenic ability, migration, and proliferation of hypoxia-pretreated HUVECs in vitro and mediate cardioprotection by upregulating proangiogenic factors and enhancing neovessel formation.

In the past decades, researchers discovered the contribution of genetic defects to the pathogenesis of primary cardiomyopathy and tried to explain the pathogenesis of these diseases by establishing a variety of disease models. Although human heart tissues and primary cardiomyocytes have advantages in modeling human heart diseases, they are difficult to obtain and culture in vitro. Defects developed in genetically modified animal models are notably different from human diseases at the molecular level. The advent of human induced pluripotent stem cells (hiPSCs) provides an unprecedented opportunity to further investigate the pathogenic mechanisms of inherited cardiomyopathies in vitro using patient-specific hiPSC-derived cardiomyocytes. In this review, we will make a summary of recent advances in in vitro inherited cardiomyopathy modeling using hiPSCs.

Abstract Background Interleukin 33 is known to have an important influence in the process of myocardial infarction, and the immunoregulatory function of MSCs could be influenced by cell factors. In this study, we evaluated the therapeutic efficacy of IL-33-overexpressing bone marrow mesenchymal stem cells (IL33-MSCs) on myocardial infarction (MI) and detected the inflammatory level and cardiac function in rats. Methods and results First, we evaluated the proliferation of T cells and polarization of macrophages that had been co-cultured with Vector-MSCs or IL33-MSCs. Co-culture experiments indicated that IL33-MSCs reduced T cell proliferation and enhanced CD206+ macrophage polarization. Second, we determined the inflammation level and cardiac function of PBS-, Vector-MSC-, and IL33-MSC-injected rats. Echocardiography indicated that left ventricular ejection fraction (LVEF) was enhanced in IL33-MSC-injected rats compared with Vector-MSC-injected rats. Postmortem analysis of rat heart tissue showed reduced fibrosis and less inflammation in IL33-MSC-injected rats. Conclusion These studies indicated that the IL33-MSC injection improved heart function and reduces inflammation in rats with MI compared with PBS or Vector-MSC injections. Graphical Abstract IL-33 overexpression enhances the immunomodulatory function and therapeutic effects of MSCs on acute MI via enhancing the polarization of macrophages toward M2, enhancing the differentiation of CD4+ T cells toward CD4+IL4+Th2 cells, and finally, reducing heart inflammation and enhancing heart function.

Abstract Background Ischemic heart diseases are still a threat to human health. Human pluripotent stem cell-based transplantation exhibits great promise in cardiovascular disease therapy, including heart ischemia. The purpose of this study was to compare the efficacy of human embryonic stem cell-derived cardiomyocyte (ESC-CM) therapy in two heart ischemia models, namely, permanent ischemia (PI) and myocardial ischemia reperfusion (IR). Methods Human embryonic stem cell-derived cardiomyocytes were differentiated from engineered human embryonic stem cells (ESC-Rep) carrying green fluorescent protein (GFP), herpes simplex virus-1 thymidine kinase (HSVtk), and firefly luciferase (Fluc). Two different heart ischemia models were generated by the ligation of the left anterior descending artery (LAD), and ESC-Rep-derived cardiomyocytes (ESC-Rep-CMs) were transplanted into the mouse hearts. Cardiac function was analyzed to evaluate the outcomes of ESC-Rep-CM transplantation. Bioluminescence signal analysis was performed to assess the cell engraftment. Finally, the inflammation response was analyzed by real-time PCR and ELISA. Results Cardiac function was significantly improved in the PI group with ESC-Rep-CM injection compared to the PBS-injected control, as indicated by increased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS), as well as reduced fibrotic area. However, minimal improvement by ESC-Rep-CM injection was detected in the IR mouse model. We observed similar engraftment efficiency between PI and IR groups after ESC-Rep-CM injection. However, the restricted inflammation was observed after the injection of ESC-Rep-CMs in the PI group, but not in the IR group. Transplantation of ESC-Rep-CMs can partially preserve the heart function via regulating the inflammation response in the PI model, while little improvement of cardiac function in the IR model may be due to the less dynamic inflammation response by the mild heart damage. Conclusions Our findings identified the anti-inflammatory effect of ESC-CMs as a possible therapeutic mechanism to improve cardiac function in the ischemic heart.

Abstract Background Cell therapy remains the most promising approach against ischemic heart injury. However, poor survival of engrafted cells in ischemic sites diminishes its therapeutic efficacy. Follistatin-like 1 (Fstl1) is documented as a novel pro-survival cardiokine for cardiomyocytes, and it is protective during ischemic heart injury. In the present study, we characterize the potential of Fstl1 as an effective strategy to enhance hypoxia resistance of donor cells and optimize stem cell-based therapy. Methods Murine bone marrow-derived mesenchymal stem cells (MSCs) were expanded in monolayer culture and characterized by flow cytometry. MSCs were subjected to hypoxia to mimic cardiac ischemic environment. Expression of Fstl1 was monitored 0, 24, and 48 h following hypoxia. Constitutive expression of Fstl1 in MSCs was achieved by lentivirus-mediated Fstl1 overexpression. Genetically modified MSCs were further collected for cell death and proliferation assay following 48 h of hypoxic treatment. Acute myocardial infarction (MI) model was created by ligating the left anterior descending coronary artery, while control MSCs (MSCs-mCherry) or Fstl1-overexpressing MSCs (MSCs-Fstl1) were injected into the peri-infarct zone simultaneously. Subsequently, retention of the donor cells was evaluated on post-therapy 1, 3, & 7 days. Finally, myocardial function, infarct size, inflammation, and neovascularization of the infarcted hearts were calculated thereafter. Results Expression of Fstl1 in hypoxic MSCs declines dramatically in a time-dependent manner. In vitro study further demonstrated that Fstl1 promotes survival and proliferation of hypoxic MSCs. Moreover, Fstl1 significantly prolongs MSC survival/retention after implantation. Finally, transplantation with Fstl1-overexpressing MSCs significantly improves post-MI cardiac function by limiting scar formation, reducing inflammatory response, and enhancing neovascularization. Conclusions Our results suggest Fstl1 is an intrinsic cardiokine promoting survival and proliferation of MSCs, thereby optimizing their engraftment and therapeutic efficacy during cell therapy.

Ephrin B2 (EFNB2) is the first identified and most widely used marker for arterial endothelial cells (AECs). We generated a heterozygous EFNB2-2A-mCherry reporter H1 cell line, H1-EFNB2-2A-mCherry+/− (WAe001-A-57), by CRISPR/Cas9-mediated insertion of 2A-mCherry cassette into the EFNB2 gene locus, immediately before the translation stop codon. The H1-EFNB2-2A-mCherry reporter cells were pluripotent and could differentiate into all three germ layer lineages. Simultaneous expression of mCherry was observed when expression of EFNB2 was increased during endothelial cell differentiation. Thus, the generated reporter cells enable live identification of EFNB2-positive AECs, and screening of small molecule compound and target genes that promote AEC differentiation.

Abstract Background Deep vein thrombosis (DVT) is caused by blood clotting in the deep veins. Thrombosis resolution and recanalization can be accelerated by endothelial progenitor cells. In this report, we investigated the effects of miR-126-loaded EPC-derived exosomes (miR-126-Exo) on EPCs function and venous thrombus resolution. Methods In vitro promotional effect of miR-126-Exo on the migration and tube incorporation ability of EPCs was investigated via transwell assay and tube formation assay. In addition, a mouse venous thrombosis model was constructed and treated with miR-126-Exo to clarify the therapeutic effect of miR-126-Exo by histological analysis. Lastly, this study predicted a target gene of miR-126 using target prediction algorithms and confirmed it by luciferase activity assay, RT-qPCR, and Western blot. Results Transwell assay and tube formation assay indicated that miR-126-Exo could enhance the migration and tube incorporation ability of EPCs. Moreover, in vivo study manifested enhanced thrombus organization and recanalization after miR-126-Exo treatment. Meanwhile, we identified that Protocadherin 7 as a target gene of miR-126. Conclusions To sum up, our results demonstrated that EPC-derived exosomes loaded with miR-126 significantly promoted thrombus resolution in an animal model of venous thrombosis, indicating exosomes as a promising potential vehicle carrying therapeutic molecules for DVT therapy.

Abstract Background Circular RNAs (circRNAs) are regarded as a novel class of noncoding RNA regulators. Although a number of circRNAs have been identified by bioinformatics analysis of RNA-seq data, tissue and disease-specific circRNAs are still to be uncovered to promote their application in basic research and clinical practice. The purpose of this study was to explore the circRNA profiles in human induced pluripotent stem cells (hiPSCs) and hiPSC-derived cardiomyocytes (hiPSC-CMs), and to identify cardiac or disease-specific circRNAs. Methods hiPSCs were generated from fibroblasts, and then further differentiated to hiPSC-CMs by modulating WNT signaling in RPMI+B27 medium. Following high-throughput RNA sequencing, circRNAs were extracted and quantified by a combined strategy known as CIRCexplorer. Integrative analysis was performed to illuminate the correlation between circRNAs and their parental linear isoforms. Cardiac and disease-specific expression of circRNAs was confirmed by quantitative reverse-transcription PCR. Results In this study, a total of 5602 circRNAs were identified in hiPSCs and hiPSC-CMs. Our data indicated, for the first time, more enriched expression of circRNAs in differentiated cardiomyocytes than in undifferentiated hiPSCs. In addition to the host gene-dependent expression, our integrative analysis also identified a number of circRNAs showing host gene-independent expression in hiPSCs and hiPSC-CMs. CircRNAs including circSLC8A1, circCACNA1D, circSPHKAP and circALPK2 showed cardiac-selective expression during cardiac differentiation and human heart-specific enrichment in fetal tissues. Furthermore, circSLC8A1 abnormally increased in heart tissues from patients suffering from dilated cardiomyopathy. Conclusions CircRNAs are highly enriched in hiPSC-differentiated CMs, and cardiac-specific circRNAs such as circSLC8A1, circCACNA1D, circSPHKAP and circALPK2 may serve as biomarkers of CMs. Detection of the excessive expression of circSLC8A1 provides a potential approach for pathological status indication of heart disease.

Abstract Background Our study aim was to evaluate the therapeutic efficacy and mechanisms of miR-133-overexpressing mesenchymal stem cells (MSCs) on acute myocardial infarction. Methods Rat MSCs were isolated and purified by whole bone marrow adherent culturing. After transfection with the agomir or antagomir of miR-133, MSCs were collected for assay of cell vitality, apoptosis, and cell cycle progression. At the same time, exosomes were isolated from the supernatant to analyze the paracrine miR-133. For in-vivo studies, constitutive activation of miR-133 in MSCs was achieved by lentivirus-mediated miR-133 overexpression. A rat myocardial infarction model was created by ligating the left anterior descending coronary artery, while control MSCs (vector-MSCs) or miR-133-overexpressed MSCs (miR-133-MSCs) were injected into the zone around the myocardial infarction. Subsequently, myocardial function was evaluated by echocardiography on days 7 and 28 post infarction. Finally the infarcted hearts were collected on days 7 and 28 for myocardial infarct size measurement and detection of snail 1 expression. Results Hypoxia-induced apoptosis of MSCs obviously reduced, along with enhanced expression of total poly ADP-ribose polymerase protein, after miR-133 agomir transfection, while the apoptosis rate increased in MSCs transfected with miR-133 antagomir. However, no change in cell viability and cell-cycle distribution was observed in control, miR-133-overexpressed, and miR-133-interfered MSCs. Importantly, rats transplanted with miR-133-MSCs displayed more improved cardiac function after acute myocardial infarction, compared with those that received vector-MSC injection. Further studies indicated that cardiac expression of snail 1 was significantly repressed by adjacent miR-133-overexpressing MSCs, and both the inflammatory level and the infarct size decreased in miR-133-MSC-injected rat hearts. Conclusions miR-133-MSCs obviously improved cardiac function in a rat model of myocardial infarction. Transplantation of miR-133-overexpressing MSCs provides an effective strategy for cardiac repair and modulation of cardiac-related diseases.

Abstract Background Neovascularization is impaired in diabetes mellitus, which leads to the development of peripheral arterial disease and is mainly attributed to the dysfunction of endothelial progenitor cells (EPCs). Previous studies proved the promotional effect of curcumin on neovascularization in wound healing of diabetes. Thus, we hypothesize that curcumin could promote neovascularization at sites of hindlimb ischemia in diabetes and might take effect via modulating the function of EPCs. Methods Streptozotocin-induced type 1 diabetic mice and nondiabetic mice both received unilateral hindlimb ischemic surgery. Curcumin was then administrated to the mice by lavage for 14 days consecutively. Laser Doppler perfusion imaging was conducted to demonstrate the blood flow reperfusion. Capillary density was measured in the ischemic gastrocnemius muscle. In addition, angiogenesis, migration, proliferation abilities, and senescence were determined in EPCs isolated from diabetic and nondiabetic mice. Quantitative PCR was then used to determine the mRNA expression of vascular endothelial growth factor (VEGF) and angiopoetin-1 (Ang-1) in EPCs. Results Curcumin application to type 1 diabetic mice significantly improved blood reperfusion and increased the capillary density in ischemic hindlimbs. The in-vitro study also revealed that the angiogenesis, migration, and proliferation abilities of EPCs and the number of senescent EPCs were reversed by curcumin application. Quantitative PCR confirmed the overexpression of VEGF-A and Ang-1 in EPCs after curcumin treatment. Conclusion Curcumin could enhance neovascularization via promoting the function of EPCs in a diabetic mouse hindlimb ischemia model.

Abstract Adipose-derived stem cells (ADSCs) are easily obtained and expanded, and have emerged as a novel source of adult stem cells for the treatment of cardiovascular diseases. These cells have been shown to have the capability of differentiating into cardiomyocytes, vascular smooth muscle cells, and endothelial cells. Furthermore, ADSCs secrete a series of paracrine factors to promote neovascularization, reduce apoptosis, and inhibit fibrosis, which contributes to cardiac regeneration. As a novel therapy in the regenerative field, ADSCs still face various limitations, such as low survival and engraftment. Thus, engineering and pharmacological studies have been conducted to solve these problems. Investigations have moved into phase I and II clinical trials examining the safety and efficacy of ADSCs in the setting of myocardial infarction. In this review, we discuss the differentiation and paracrine functions of ADSCs, the strategies promoting their therapeutic efficacy, and their clinical usage.

Abstract Cardiovascular diseases are the leading causes of death in the world. The limited regenerative capacity of adult cardiomyocytes is the major barrier for heart regeneration. After myocardial infarction, myofibroblasts are the dominant cell type in the infarct zone. Therefore, it is a good idea to reprogram terminally differentiated myofibroblasts into cardiomyocyte-like cells directly, providing a good strategy to simultaneously reduce scar tissue and increase functional cardiomyocytes. Transcription factors were first identified to reprogram myofibroblasts into cardiomyocytes. Thereafter, microRNAs and/or small molecules showed great potential to optimize the reprogramming process. Here, we systemically summarize and compare the major progress in directed cardiac reprogramming including transcription factors and miRNAs, especially the small molecules. Furthermore, we discuss the challenges needed to be overcome to apply this strategy clinically.

Background/Aims: Bone marrow mesenchymal stem cells (MSCs) widely applied for treating myocardial infarction face survival challenges in the inflammatory and ischemia microenvironment of acute myocardial infarction. The study hypothesized that MSC-derived exosomes play a significant role in improving microenvironment after acute myocardial infarction and aimed to investigate the paracrine effects of exosomes on angiogenesis and anti-inflammatory activity. Methods: MSCs were cultured in DMEM/F12 supplemented with 10% exosome-depleted fetal bovine serum and 1% penicillin-streptomycin for 48 h. MSC-derived exosomes were isolated using ExoQuick-TC. Tube formation and T-cell proliferation assays were performed to assess the angiogenic potency of MSC-derived exosomes. Acute myocardial infarction was induced in Sprague-Dawley rats, and myocardium bordering the infarcted zone was injected at four different sites with phosphate-buffered saline (PBS, control), MSC-derived exosomes, and exosome-depleted MSC culture medium. Results: MSC-derived exosomes significantly enhanced the tube formation of human umbilical vein endothelial cells, impaired T-cell function by inhibiting cell proliferation in vitro, reduced infarct size, and preserved cardiac systolic and diastolic performance compared with PBS markedly enhancing the density of new functional capillary and hence blood flow recovery in rat myocardial infarction model. Conclusions: Exosomes stimulate neovascularization and restrain the inflammation response, thus improving heart function after ischemic injury.

Background Exosomes are membranous vesicles generated by almost all cells. Recent studies demonstrated that mesenchymal stem cell–derived exosomes possessed many effects, including antiapoptosis, anti‐inflammatory effects, stimulation of angiogenesis, anticardiac remodeling, and recovery of cardiac function on cardiovascular diseases. However, targeting of exosomes to recipient cells precisely in vivo still remains a problem. Ligand fragments or homing peptides discovered by phage display and in vivo biopanning methods fused to the enriched molecules on the external part of exosomes have been exploited to improve the ability of exosomes to target specific tissues or organs carrying cognate receptors. Herein, we briefly elucidated how to improve targeting ability of exosomes to ischemic myocardium. Methods and Results We used technology of molecular cloning and lentivirus packaging to engineer exosomal enriched membrane protein (Lamp2b) fused with ischemic myocardium‐targeting peptide CSTSMLKAC (IMTP). In vitro results showed that IMTP‐exosomes could be internalized by hypoxia‐injured H9C2 cells more efficiently than blank‐exosomes. Compared with blank‐exosomes, IMTP‐exosomes were observed to be increasingly accumulated in ischemic heart area (P

Background. To cure ischemic diseases, angiogenesis needs to be improved by various strategies in ischemic area. Considering that microRNA-132 (miR-132) regulates endothelial cell behavior during angiogenesis and the safe and efficacious delivery of microRNAs in vivo is rarely achieved, an ideal vehicle for miR-132 delivery could bring the promise for ischemic diseases. As a natural carrier of biological molecules, exosomes are more and more developed as an ideal vehicle for miRNA transfer. Meanwhile, mesenchymal stem cells could release large amounts of exosomes. Thus, this study aimed to investigate whether MSC-derived exosomes can be used for miR-132 delivery in the treatment of myocardial ischemia. Methods. MSC-derived exosomes were electroporated with miR-132 mimics and inhibitors. After electroporation, miR-132 exosomes were labelled with DiI and added to HUVECs. Internalization of DiI-labelled exosomes was examined by fluorescent microscopy. Expression levels of miR-132 in exosomes and HUVECs were quantified by real-time PCR. The mRNA levels of miR-132 target gene RASA1 in HUVECs were quantified by real-time PCR. Luciferase reporter assay was performed to examine the targeting relationship between miR-132 and RASA1. The effects of miR-132 exosomes on the angiogenic ability of endothelial cells were evaluated by tube formation assay. Matrigel plug assay and myocardial infarction model were used to determine whether miR-132 exosomes can promote angiogenesis in vivo. Results. miR-132 mimics were effectively electroporated and highly detected in MSC-derived exosomes. The expression level of miR-132 was high in HUVECs preincubated with miR-132 mimic-electroporated exosomes and low in HUVECs preincubated with miR-132 inhibitor-electroporated exosomes. The expression level of RASA1, miR-132 target gene, was reversely correlated with miR-132 expression in HUVECs pretreated with exosomes. Luciferase reporter assay further confirmed that RASA1 was a direct target of miR-132. Exosomes loaded with miR-132, as a vehicle for miRNA transfer, significantly increased tube formation of endothelial cells. Moreover, subcutaneous injection of HUVECs pretreated with miR-132 exosomes in nude mice significantly increased their angiogenesis capacity in vivo. In addition, transplantation of miR-132 exosomes in the ischemic hearts of mice markedly enhanced the neovascularization in the peri-infarct zone and preserved heart functions. Conclusions. The findings suggest that the export of miR-132 via MSC-derived exosomes represents a novel strategy to enhance angiogenesis in ischemic diseases.

The authors have retracted this article [1] because there is erroneous data in Figure 1C. Flow cytometry results of EPC cell markers CD31 and CD45 could not be replicated. Due to incorrect cell markers, the cells cultured may not have been pure EPCs. Therefore the scientific content of the article is no longer reliable. All authors agree to this retraction.

Researches show that androgens have important effects on migration of endothelial cells and endothelial protection in coronary heart disease. Endothelial progenitor cells (EPCs) as a progenitor cell type that can differentiate into endothelial cells, have a critical role in angiogenesis and endothelial protection. The relationship between androgen and the functions of EPCs has animated much interest and controversy. In this study, we investigated the angiogenic and migratory functions of EPCs after treatment by dihydrotestosterone (DHT) and the molecular mechanisms as well. We found that DHT treatment enhanced the incorporation of EPCs into tubular structures formed by HUVECs and the migratory activity of EPCs in the transwell assay dose dependently. Moreover, microarray analysis was performed to explore how DHT changes the gene expression profiles of EPCs. We found 346 differentially expressed genes in androgen-treated EPCs. Angiogenesis-related genes like Egr-1, Vcan, Efnb2, and Cdk2ap1 were identified to be regulated upon DHT treatment. Furthermore, the enhanced angiogenic and migratory abilities of EPCs after DHT treatment were inhibited by Egr1-siRNA transfection. In conclusion, our findings suggest that DHT markedly enhances the vessel forming ability and migration capacity of EPCs. Egr1 signaling may be a possible pathway in this process.

Cardiac hypertrophy is an adaptive enlargement of the myocardium in response to overload pressure of heart. From abundant studies, a conclusion is drawn that many microRNAs (miRNAs) are associated with cardiac hypertrophy and heart failure. To investigate the role of microRNA-497 (miR-497) in myocardial hypertrophy, two models were established in this study from cell level to integral level. Cardiac hypertrophy was induced by using angiotensin Ⅱ (Ang Ⅱ) in vitro and was created by transverse abdominal aortic constriction (TAC) in vivo. There was a significant decrease expression of miR-497 in cardiac hypertrophy models. Moreover, overexpression of miR-497 inhibited myocardial hypertrophy both in vitro and in vivo without heart function variation. In addition, luciferase reporter assays demonstrated that Sirt4 was a direct target gene of miR-497. Taking together, our study indicates that miR-497 modulates cardiac hypertrophy by targeting Sirt4 and may serve as a potential therapeutic substance in the course.

BackgroundExosomes derived from mesenchymal stem cells (MSCs) were proved to boost cell proliferation and angiogenic potency. We explored whether cardiac stem cells (CSCs) preconditioned with MSC exosomes could survive and function better in a myocardial infarction model. Methods and ResultsDiI‐labeled exosomes were internalized with CSCs. They stimulated proliferation, migration, and angiotube formation of CSCs in a dose‐dependent manner. In a rat myocardial infarction model, MSC exosome–preconditioned CSCs had significantly better survival, enhanced capillary density, reduced cardiac fibrosis, and restored long‐term cardiac function. MicroRNA profiling analysis revealed that a set of microRNAs were significantly changed in CSCs after MSC exosome treatment. ConclusionsPretreatment of CSCs with MSC exosomes provided a promising strategy to improve survival and angiogenic potency of CSCs.

With the high mortality rate, coronary heart disease (CHD) has currently become a major life-threatening disease. The main pathological change of myocardial infarction (MI) is the induction of myocardial necrosis in infarction area which finally causes heart failure. Conventional treatments cannot regenerate the functional cell efficiently. Recent researches suggest that mesenchymal stem cells (MSCs) are able to differentiate into multiple lineages, including cardiomyocyte-like cells in vitro and in vivo, and they have been used for the treatment of MI to repair the injured myocardium and improve cardiac function. In this review, we will focus on the recent progress on MSCs derived cardiomyocytes for cardiac regeneration after MI.

Background and objectives: Due to the high individual variability of anticoagulant warfarin, this study aimed to investigate the effects of vitamin K concentration and gut microbiota on individual variability of warfarin in 246 cardiac surgery patients. Methods: The pharmacokinetics and pharmacodynamics (PKPD) model predicted international normalized ratio (INR) and warfarin concentration. Serum and fecal samples were collected to detect warfarin and vitamin K [VK1 and menaquinone-4 (MK4)] concentrations and gut microbiota diversity, respectively. In addition, the patient's medical records were reviewed for demographic characteristics, drug history, and CYP2C9, VKORC1, and CYP4F2 genotypes. Results: The PKPD model predicted ideal values of 62.7% for S-warfarin, 70.4% for R-warfarin, and 76.4% for INR. The normal VK1 level was 1.34 ± 1.12 nmol/ml (95% CI: 0.33-4.08 nmol/ml), and the normal MK4 level was 0.22 ± 0.18 nmol/ml (95% CI: 0.07-0.63 nmol/ml). The MK4 to total vitamin K ratio was 16.5 ± 9.8% (95% CI: 4.3-41.5%). The S-warfarin concentration of producing 50% of maximum anticoagulation and the half-life of prothrombin complex activity tended to increase with vitamin K. Further, Prevotella and Eubacterium of gut microbiota identified as the main bacteria associated with individual variability of warfarin. The results suggest that an increase in vitamin K concentration can decrease anticoagulation, and gut microbiota may influence warfarin anticoagulation through vitamin K2 synthesis. Conclusion: This study highlights the importance of considering vitamin K concentration and gut microbiota when prescribing warfarin. The findings may have significant implications for the personalized use of warfarin. Further research is needed to understand better the role of vitamin K and gut microbiota in warfarin anticoagulation. [ABSTRACT FROM AUTHOR]