Targeting delivery of miR-146a via IMTP modified milk exosomes exerted cardioprotective effects by inhibiting NF-κB signaling pathway after myocardial ischemia-reperfusion injury.

Reperfusion therapy is critical for saving heart muscle after myocardial infarction, but the process of restoring blood flow can itself exacerbate injury to the myocardium. This phenomenon is known as myocardial ischemia-reperfusion injury (MIRI), which includes oxidative stress, inflammation, and further cell death. microRNA-146a (miR-146a) is known to play a significant role in regulating the immune response and inflammation, and has been studied for its potential impact on the improvement of heart function after myocardial injury. However, the delivery of miR-146a to the heart in a specific and efficient manner remains a challenge as extracellular RNAs are unstable and rapidly degraded. Milk exosomes (MEs) have been proposed as ideal delivery platform for miRNA-based therapy as they can protect miRNAs from RNase degradation. In this study, the effects of miR-146a containing MEs (MEs-miR-146a) on improvement of cardiac function were examined in a rat model of MIRI. To enhance the targeting delivery of MEs-miR-146a to the site of myocardial injury, the ischemic myocardium-targeted peptide IMTP was modified onto the surfaces, and whether the modified MEs-miR-146a could exert a better therapeutic role was examined by echocardiography, myocardial injury indicators and the levels of inflammatory factors. Furthermore, the expressions of miR-146a mediated NF-κB signaling pathway-related proteins were detected by western blotting and qRT-PCR to further elucidate its mechanisms. MiR-146 mimics were successfully loaded into the MEs by electroporation at a square wave 1000 V voltage and 0.1 ms pulse duration. MEs-miR-146a can be up-taken by cardiomyocytes and protected the cells from oxygen glucose deprivation/reperfusion induced damage in vitro. Oral administration of MEs-miR-146a decreased myocardial tissue apoptosis and the expression of inflammatory factors and improved cardiac function after MIRI. The miR-146a level in myocardium tissues was significantly increased after the administration IMTP modified MEs-miR-146a, which was higher than that of the MEs-miR-146a group. In addition, intravenous injection of IMTP modified MEs-miR-146a enhanced the targeting to heart, improved cardiac function, reduced myocardial tissue apoptosis and suppressed inflammation after MIRI, which was more effective than the MEs-miR-146a treatment. Moreover, IMTP modified MEs-miR-146a reduced the protein levels of IRAK1, TRAF6 and p-p65. Therefore, IMTP modified MEs-miR-146a exerted their anti-inflammatory effect by inhibiting the IRAK1/TRAF6/NF-κB signaling pathway. Taken together, our findings suggested miR-146a containing MEs may be a promising strategy for the treatment of MIRI with better outcome after modification with ischemic myocardium-targeted peptide, which was expected to be applied in clinical practice in future.

Transplantation of induced pluripotent stem cells-derived cardiomyocytes combined with modified Taohong Siwu decoction improved heart repair after myocardial infarction.

Objective: This study aimed to study whether modified Taohong Siwu decoction (MTHSWD) combined with human induced pluripotent stem cells-derived cardiomyocytes (iPS-CMs) transplantation can promote cardiac function in myocardial infarction (MI) nude mouse model and explore its possible mechanism. Methods: The MI mouse model was established by the ligation of left anterior descending coronary artery. After 4 weeks of gavage of MTHSWD combined with iPS-CMs transplantation, the changes in heart function of mice were examined by echocardiography. The histological changes were observed by Masson's trichrome staining. The survival and differentiation of transplanted cells were detected by double immunofluorescence staining of human nuclear antigen (HNA) and cardiac troponin T (cTnT). The number of c-kit-positive cells in the infarct area were evaluated by immunofluorescent staining. The levels of stromal cell-derived factor 1 (SDF-1), stem cell factor (SCF), vascular endothelial growth factor (VEGF) and basic fibroblast growth factor in infarcted myocardium tissues were detected by ELISA. Results: MTHSWD combined with iPS-CMs transplantation can improve the heart function of MI mice, reduce the infarct size and collagen deposition in infarct area. By immunofluorescence double-label detection of HNA and cTnT, it was found that MTHSWD combined with iPS-CMs transplantation can improve the survival and maturation of iPS-CMs. In addition, MTHSWD combined with iPS-CMs transplantation can activate more endogenous c-kit positive cardiac mesenchymal cells, and significantly increase the content of SDF-1, SCF and VEGF in myocardial tissues. Conclusions: The combination of MTHSWD with iPS-CMs transplantation promoted cardiac function of nude mice with MI by improving the survival and maturation of iPS-CMs in the infarct area, activating the endogenous c-kit positive cardiac mesenchymal cells, and increasing paracrine.

Small Extracellular Vesicles Derived from Induced Pluripotent Stem Cells in the Treatment of Myocardial Injury.

Induced pluripotent stem cell (iPSC) therapy brings great hope to the treatment of myocardial injuries, while extracellular vesicles may be one of the main mechanisms of its action. iPSC-derived small extracellular vesicles (iPSCs-sEVs) can carry genetic and proteinaceous substances and mediate the interaction between iPSCs and target cells. In recent years, more and more studies have focused on the therapeutic effect of iPSCs-sEVs in myocardial injury. IPSCs-sEVs may be a new cell-free-based treatment for myocardial injury, including myocardial infarction, myocardial ischemia-reperfusion injury, coronary heart disease, and heart failure. In the current research on myocardial injury, the extraction of sEVs from mesenchymal stem cells induced by iPSCs was widely used. Isolation methods of iPSCs-sEVs for the treatment of myocardial injury include ultracentrifugation, isodensity gradient centrifugation, and size exclusion chromatography. Tail vein injection and intraductal administration are the most widely used routes of iPSCs-sEV administration. The characteristics of sEVs derived from iPSCs which were induced from different species and organs, including fibroblasts and bone marrow, were further compared. In addition, the beneficial genes of iPSC can be regulated through CRISPR/Cas9 to change the composition of sEVs and improve the abundance and expression diversity of them. This review focused on the strategies and mechanisms of iPSCs-sEVs in the treatment of myocardial injury, which provides a reference for future research and the application of iPSCs-sEVs.

Lymphangiogenesis, a potential treatment target for myocardial injury.

The lymphatic vascular system is crucial for the regulation of tissue fluid homeostasis, lipid metabolism, and immune function. Cardiac injury quickly leads to myocardial edema, cardiac lymphatic dysfunction, which ultimately results in myocardial fluid imbalance and cardiac dysfunction. Therefore, lymphangiogenesis-targeted therapy may improve the recovery of myocardial function post cardiac ischemia as observed in myocardial infarction (MI). Indeed, a promising strategy for the clinical treatment of MI relies on vascular endothelial growth factor-C (VEGF-C)-targeted therapy, which promotes lymphangiogenesis. However, much effort is needed to identify the mechanisms of lymphatic transport in response to heart disease. This article reviews regulatory factors of lymphangiogenesis, and discusses the effects of lymphangiogenesis on cardiac function after cardiac injury and its regulatory mechanisms. The involvement of stem cells on lymphangiogenesis was also discussed as stem cells could differentiate into lymphatic endothelial cells (LECs) and stimulate phenotype of LECs.

Modified Taohong Siwu decoction improves cardiac function after myocardial ischaemia and reperfusion in rats by promoting endogenous stem cell mobilization and regulating metabolites.

CONTEXT: Taohong Siwu decoction (THSWD) has been shown to promote heart repair in myocardial infarction. OBJECTIVE: To determine the effects of modified THSWD (THSWD plus four ingredients) on myocardial ischaemia and reperfusion (I/R) injury. MATERIALS AND METHODS: Sixty Sprague-Dawley rats were randomly divided into the I/R group and three different modified THSWD dose groups (gavage administration, 1.215, 2.43, and 4.86 g, respectively). 2,3,5-Triphenyltetrazolium chloride and Evans blue staining were used to detect the infarct area at 24 h after treatment. The serum biochemical indexes and cell apoptosis were examined to determine myocardial injury. The number of endogenous stem cells, expression of stromal dell derived factor-1 (SDF-1) and stem cell factor (SCF), and cardiac function were measured at 4 weeks. The serum was collected for metabolomic analysis. RESULTS: The high-dose modified THSWD group presented a reduced infarction area (decreased by 21.3%), decreased levels of lactate dehydrogenase and creatinine kinase, attenuated cell apoptosis, and enhanced superoxide dismutase activity in early stage I/R compared with other groups. The serum SCF and SDF-1 levels were higher in the high-dose group than in the I/R group. At 4 weeks, the infarct size and collagen content were the lowest, and the ejection fraction and fractional shortening values were the highest in the high-dose group. Moreover, high-dose modified THSWD affected the metabolism of phosphonate and phosphonate, taurine, and hypotaurine. CONCLUSIONS: Endogenous stem cell mobilization and metabolic regulation were related to the cardioprotection of modified THSWD. We provided a new strategy and direction for the treatment of cardiovascular diseases with traditional Chinese medicine.