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.

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.

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.

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.

Self-assembling peptide modified with QHREDGS as a novel delivery system for mesenchymal stem cell transplantation after myocardial infarction.

The lower cell survival and retention in the hostile microenvironment after transplantation has been implicated as a major bottleneck in the advancement of stem cell therapy for myocardial infarction (MI). In this study, we designed a novel self-assembling peptide (SAP) by attaching prosurvival peptide QHREDGS derived from angiopoeitin-1 to the known SAP, RADA16-I. The mesenchymal stem cells (MSCs) were harvested from male rats and cytoprotective effect of this designer SAP (DSAP) on cultured MSCs was detected by Hoechst 33342 staining after being exposed to oxygen and glucose deprivation (OGD). The cytoprotective effect of MSCs seeded in DSAP (DSAP-MSCs) on OGD treated cardiomyocytes was examined by TUNEL staining, phosphorylated (p-) protein kinase B (Akt) level, and ELISA. The therapeutic potential of MSC transplantation carried in DSAP was evaluated in a female rat MI model. PBS, MSCs alone, MSCs seeded in SAP (SAP-MSCs), or DSAP-MSCs were transplanted into the border of the infarcted area, respectively. DSAP not only increased the proliferation of MSCs and decreased apoptosis of MSCs after OGD treatment but also promoted the secretion of IGF-1 and HGF in MSCs. Treatment with culture supernatant of DSAP-MSCs markedly reduced the percentage of apoptotic cardiomyocytes and increased the level of p-Akt. Compared with the MSC group and SAP-MSC group, DSAP-MSC injection improved cardiac function and reduced infarct size, collagen content, and cell apoptosis. The number of Y chromosome-positive cells and microvessels in the DSAP-MSC group was higher than those in the MSC group and SAP-MSC group. Moreover, DSAP-MSC transplantation down-regulated the expression of IL-6 and IL-1ß and up-regulated the level of VEGF and HGF. Interestingly, miR-21 was enriched in DSAP-MSC-derived exosomes (DSAP-MSC-Exos) and the protection against cardiomyocyte apoptosis by DSAP-MSC-Exos was inhibited when miR-21 was knocked down. Furthermore, miR-21 contributed to the improvement of cardiac function after DSAP-MSC-Exo injection in a rat model of MI. Additionally, the combination of DSAP and cardiotrophin-1 (Ctf1) pretreatment further improved the survival of MSCs and the efficiency of MSC transplantation. We proposed QHREDGS-modified SAP as an effective cell delivery system and demonstrated that MSC transplantation in this DSAP promoted angiogenesis and paracrine, thereby reducing scar size and cell apoptosis as well as improving cardiac function probably via exosome-mediated miR-21 after MI. Furthermore, for the first time, we proposed that DSAP, especially working together with Ctf1 pretreatment, could be a valuable way to improve the survival of MSCs and the efficiency of MSC transplantation after MI.-Cai, H., Wu, F.-Y., Wang, Q.-L., Xu, P., Mou, F.-F., Shao, S.-J., Luo, Z.-R., Zhu, J., Xuan, S.-S., Lu, R., Guo, H.-D. Self-assembling peptide modified with QHREDGS as a novel delivery system for mesenchymal stem cell transplantation after myocardial infarction.

Exosomes derived from hypoxia-preconditioned mesenchymal stromal cells ameliorate cognitive decline by rescuing synaptic dysfunction and regulating inflammatory responses in APP/PS1 mice.

Administration of exosomes derived from mesenchymal stromal cells (MSCs) could improve some neurologic conditions by transferring functional biomolecules to recipient cells. Furthermore, exosomes from hypoxic progenitor cells exerted better therapeutic effects in organ injury through specific cargoes. However, there are no related reports about whether exosomes derived from MSCs or hypoxia-preconditioned MSCs (PC-MSCs) could prevent memory deficits in Alzheimer disease (AD). In this study, the exosomes derived from MSCs or PC-MSCs were systemically administered to transgenic APP/PS1 mice. The expression of miR-21 in MSCs was significantly increased after hypoxic treatment. Injection of exosomes from normoxic MSCs could rescue cognition and memory impairment according to results of the Morris water maze test, reduced plaque deposition, and Aß levels in the brain; could decrease the activation of astrocytes and microglia; could down-regulate proinflammatory cytokines (TNF-α and IL-1ß); and could up-regulate anti-inflammatory cytokines (IL-4 and -10) in AD mice, as well as reduce the activation of signal transducer and activator of transcription 3 (STAT3) and NF-κB. Compared to the group administered exosomes from normoxic MSCs, in the group administered exosomes from PC-MSCs, learning and memory capabilities were significantly improved; the plaque deposition and Aß levels were lower, and expression of growth-associated protein 43, synapsin 1, and IL-10 was increased; and the levels of glial fibrillary acidic protein, ionized calcium-binding adaptor molecule 1, TNF-α, IL-1ß, and activation of STAT3 and NF-κB were sharply decreased. More importantly, exosomes from PC-MSCs effectively increased the level of miR-21 in the brain of AD mice. Additionally, replenishment of miR-21 restored the cognitive deficits in APP/PS1 mice and prevented pathologic features. Taken together, these findings suggest that exosomes from PC-MSCs could improve the learning and memory capabilities of APP/PS1 mice, and that the underlying mechanism may lie in the restoration of synaptic dysfunction and regulation of inflammatory responses through regulation of miR-21.-Cui, G.-H., Wu, J., Mou, F.-F., Xie, W.-H., Wang, F.-B., Wang, Q.-L., Fang, J., Xu, Y.-W., Dong, Y.-R., Liu, J.-R., Guo, H.-D. Exosomes derived from hypoxia-preconditioned mesenchymal stromal cells ameliorate cognitive decline by rescuing synaptic dysfunction and regulating inflammatory responses in APP/PS1 mice.

RVG-modified exosomes derived from mesenchymal stem cells rescue memory deficits by regulating inflammatory responses in a mouse model of Alzheimer's disease.

BACKGROUND: Exosomes are lipid-bilayer enclosed nano-sized vesicles that transfer functional cellular proteins, mRNA and miRNAs. Mesenchymal stem cells (MSCs) derived exosomes have been demonstrated to prevent memory deficits in the animal model of Alzheimer's disease (AD). However, the intravenously injected exosomes could be abundantly tracked in other organs except for the targeted regions in the brain. Here, we proposed the use of central nervous system-specific rabies viral glycoprotein (RVG) peptide to target intravenously-infused exosomes derived from MSCs (MSC-Exo) to the brain of transgenic APP/PS1 mice. MSC-Exo were conjugated with RVG through a DOPE-NHS linker. RESULTS: RVG-tagged MSC-Exo exhibited improved targeting to the cortex and hippocampus after being administered intravenously. Compared with the group administered MSC-Exo, in the group administered RVG-conjugated MSC-Exo (MSC-RVG-Exo) plaque deposition and Aß levels were sharply decreased and activation of astrocytes was obviously reduced. The brain targeted exosomes derived from MSCs was better than unmodified exosomes to improve cognitive function in APP/PS1 mice according to Morris water maze test. Additionally, although MSC-Exo injected intravenously reduced the expression of pro-inflammatory mediators TNF-α, IL-ß, and IL-6, but the changes of anti-inflammatory factors IL-10 and IL-13 were not obvious. However, administration of MSC-RVG-Exo significantly reduced the levels of TNF-α, IL-ß, and IL-6 while significantly raised the levels of IL-10, IL-4 and IL-13. CONCLUSIONS: Taken together, our results demonstrated a novel method for increasing delivery of exosomes for treatment of AD. By targeting exosomes to the cortex and hippocampus of AD mouse, there was a significant improvement in learning and memory capabilities with reduced plaque deposition and Aß levels, and normalized levels of inflammatory cytokines.

Delivery of Stem Cells and BMP-2 With Functionalized Self-Assembling Peptide Enhances Regeneration of Infarcted Myocardium.

Stem cell transplantation is a promising therapeutic strategy for myocardial infarction (MI). However, engraftment, survival and differentiation of the transplanted stem cells in ischemic and inflammatory microenvironment are poor. We designed a novel self-assembly peptide (SAP) by modifying the peptide RADA16 with cell-adhesive motif and BMP-2 (bone morphogenetic protein-2)-binding motif. Effects of the functionalized SAP on adhesion, survival and differentiation of c-kit+ MSCs (mesenchymal stem cells) were examined. Myocardial regeneration, neovascularization and cardiac function were assessed after transplantation of the SAP loading c-kit+ MSCs and BMP-2 in rat MI models. The SAP could spontaneously assemble into well-ordered nanofibrous scaffolds. The cells adhered to the SAP scaffolds and spread well. The SAP protected the cells in the condition of hypoxia and serum deprivation. Following degradation of the SAP, BMP-2 was released sustainedly and induced c-kit+ MSCs to differentiate into cardiomyocytes. At four weeks after transplantation of the SAP loading c-kit+ MSCs and BMP-2, myocardial regeneration and angiogenesis were enhanced, and cardiac function was improved significantly. The cardiomyocytes differentiated from the engrafted c-kit+ MSCs were increased markedly. The differentiated cells connected with recipient cardiomyocytes to form gap junctions. Collagen volume was decreased dramatically. These results suggest that the functionalized SAP promotes engraftment, survival and differentiation of stem cells effectively. Local sustained release of BMP-2 with SAP is a viable strategy to enhance differentiation of the engrafted stem cells and repair of the infarcted myocardium.

Electroacupuncture Promotes Nerve Regeneration and Functional Recovery Through Regulating lncRNA GAS5 Targeting miR-21 After Sciatic Nerve Injury.

Although the benefits of electroacupuncture (EA) for peripheral nerve injury (PNI) are well accepted in clinical practice, the underlying mechanism remains incompletely elucidated. In our study, we observed that EA intervention led to a reduction in the expression of the long non-coding RNA growth-arrest-specific transcript 5 (GAS5) and an increased in miR-21 levels within the injured nerve, effectively promoting functional recovery and nerve regeneration following sciatic nerve injury (SNI). In contrast, administration of adeno-associated virus expressing GAS5 (AAV-GAS5) weakened the therapeutic effect of EA. On the other hand, both silencing GAS5 and introducing a miR-21 mimic prominently enhanced the proliferation activity and migration ability of Schwann cells (SCs), while also inhibiting SCs apoptosis. On the contrary, inhibition of SCs apoptosis was found to be mediated by miR-21. Additionally, overexpression of GAS5 counteracted the effects of the miR-21 mimic on SCs. Moreover, SCs that transfected with the miR-21 mimic promoted neurite growth in hypoxia/reoxygenation-induced neurons, which might be prevented by overexpressing GAS5. Furthermore, GAS5 was found to be widely distributed in the cytoplasm and was negatively regulated by miR-21. Consequently, the targeting of GAS5 by miR-21 represents a potential mechanism through which EA enhances reinnervation and functional restoration following SNI. Mechanistically, the GAS5/miR-21 axis can modulate the proliferation, migration, and apoptosis of SCs while potentially influencing the neurite growth of neurons.

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.

Dihydrotanshinone I reduces H9c2 cell damage by regulating AKT and MAPK signaling pathways.

Cardiovascular disease is the deadliest disease in the world. Previous studies have shown that Dihydrotanshinone I (DHT) can improve cardiac function after myocardial injury. This study aimed to observe the protective effect and mechanism of DHT on H9c2 cells by establishing an oxygen-glucose deprivation/reoxygenation (OGD/R) injury model. By constructing OGD/R injury simulation of H9c2 cells in a myocardial injury model, the proliferation of H9c2 cells treated with DHT concentrations of 0.1 µmol/L were not affected at 24, 48, and 72 h. DHT can significantly reduce the apoptosis of H9c2 cells caused by OGD/R. Compared with the OGD/R group, DHT treatment significantly reduced the level of MDA and increased the level of SOD in cells. DHT treatment of cells can significantly reduce the levels of ROS and Superoxide in mitochondria in H9c2 cells caused by OGD/R and H2O2. DHT significantly reduced the phosphorylation levels of P38MAPK and ERK in H9c2 cells induced by OGD/R, and significantly increased the phosphorylation levels of AKT in H9c2 cells. DHT can significantly reduce the oxidative stress damage of H9c2 cells caused by H2O2 and OGD/R, thereby reducing the apoptosis of H9c2 cells. And this may be related to regulating the phosphorylation levels of AKT, ERK, and P38MAPK.

Pathogenesis of miR-155 on nonmodifiable and modifiable risk factors in Alzheimer's disease.

Alzheimer's disease (AD) is a common age-related neurodegenerative disease in the central nervous system and is the primary cause of dementia. It is clinically characterized by the memory impairment, aphasia, apraxia, agnosia, visuospatial and executive dysfunction, behavioral changes, and so on. Incidence of this disease was bound up with age, genetic factors, cardiovascular and cerebrovascular dysfunction, and other basic diseases, but the exact etiology has not been clarified. MicroRNAs (miRNAs) are small endogenous non-coding RNAs that were involved in the regulation of post-transcriptional gene expression. miRNAs have been extensively studied as noninvasive potential biomarkers for disease due to their relative stability in bodily fluids. In addition, they play a significant role in the physiological and pathological processes of various neurological disorders, including stroke, AD, and Parkinson's disease. MiR-155, as an important pro-inflammatory mediator of neuroinflammation, was reported to participate in the progression of ß-amyloid peptide and tau via regulating immunity and inflammation. In this review, we put emphasis on the effects of miR-155 on AD and explore the underlying biological mechanisms which could provide a novel approach for diagnosis and treatment of AD.

Screening and identification of effective components from modified Taohong Siwu decoction for protecting H9c2 cells from damage.

We found that modified Taohong Siwu decoction (MTHSWD) had cardioprotective effects after myocardial ischemia-reperfusion injury. This study was to screen the effective components of MTHSWD that have protective effects on H9c2 cell injury through H2O2 injury model. Fifty-three active components were screened by CCK8 assay to detect cell viability. The anti-oxidative stress ability was evaluated by detecting the levels of total superoxide dismutase (SOD) and malondialdehyde (MDA) in cells. The anti-apoptotic effect was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL). Finally, the phosphorylation levels of ERK, AKT, and P38MAPK were detected by WB (Western blot) to study the protective mechanism of effective monomers against H9c2 cell injury. Among the 53 active ingredients of MTHSWD, ginsenoside Rb3, levistilide A, ursolic acid, tanshinone I, danshensu, dihydrotanshinone I, and astragaloside I could significantly increase the viability of H9c2 cells. The results of SOD and MDA showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA could significantly reduce the content of lipid peroxide in cells. TUNEL results showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA reduced apoptosis to varying degrees. The tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, and tanshinone I reduced the phosphorylation levels of P38MAPK and ERK in H9c2 cells induced by H2O2, and the phosphorylation level of ERK was also significantly reduced by danshensu. At the same time, tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, tanshinone I, and danshensu significantly increased AKT phosphorylation level in H9c2 cells. In conclusion, the effective ingredients in MTHSWD provide basic basis and experimental reference for the prevention and treatment of cardiovascular diseases.

Electroacupuncture improves cardiac function after myocardial infarction by regulating the mobilization and migration of endogenous stem cells.

OBJECTIVE: The aim of this study was to explore the role and mechanisms of electroacupuncture (EA) in the regulation of chemokines in endogenous stem cell mobilization and myocardial regeneration after myocardial infarction (MI). METHODS: An MI model was constructed in adult male Sprague-Dawley rats by ligating the left anterior descending coronary artery. After 4 weeks of treatment, echocardiography was used to detect changes in cardiac function, and Masson's trichrome staining was used to detect collagen deposition. In addition, immunofluorescence staining was applied to examine von Willebrand factor (vWF)-positive vessels, the expression of cardiac troponin T (cTnT) and proliferation marker Ki67, and the number of c-kit-positive, C-X-C chemokine receptor type 4 (CXCR4)-positive, and Sca-1-positive endogenous stem cells in the infarcted area. In addition, the expression of stromal cell-derived factor (SDF)-1 and stem cell factor (SCF) was detected. RESULTS: EA increased the ejection fraction after MI, reduced collagen deposition and cellular apoptosis, and increased the number of blood vessels compared with an untreated model group. EA significantly promoted cellular proliferation, except for myocardial cells, and significantly increased the number of c-kit-, CXCR4- and Sca-1-positive stem cells. Moreover, the expression of SDF-1 and SCF in myocardial tissue in the EA group was significantly higher than that in the (untreated) MI group. CONCLUSIONS: EA appears to promote angiogenesis and reduce collagen deposition, thus improving the cardiac function of rats with MI. The underlying mechanism of action may involve endogenous stem cell mobilization mediated by SDF-1/CXCR4 and SCF/c-kit.

Sustained delivery of VEGF from designer self-assembling peptides improves cardiac function after myocardial infarction.

Poor vascularization and insufficient oxygen supply are detrimental to the survival of residual cardiomyocytes or transplanted stem cells after myocardial infarction. To prolong and slow the release of angiogenic factors, which stimulate both angiogenesis and vasculogenesis, we constructed a novel self-assembling peptide by attaching the heparin-binding domain sequence LRKKLGKA to the self-assembling peptide RADA16. This designer self-assembling peptide self-assembled into nanofiber scaffolds under physiological conditions, as observed by atomic force microscopy. The injection of designer self-assembling peptides can efficiently provide the sustained delivery of VEGF for at least 1 month. At 4 weeks after transplantation, cardiac function was improved, and scar size and collagen deposition were markedly reduced in the group receiving VEGF with the LRKKLGKA scaffolds compared with groups receiving VEGF alone, LRKKLGKA scaffolds alone or VEGF with RADA16 scaffolds. The microvessel density in the VEGF with LRKKLGKA group was higher than that in the VEGF with RADA16 group. TUNEL and cleaved caspase-3 expression assays showed that the transplantation of VEGF with LRKKLGKA enhanced cell survival in the infarcted heart. These results present the tailor-made peptide scaffolds as a new generation of sustained-release biomimetic biomaterials and suggest that the use of angiogenic factors along with designer self-assembling peptides can lead to myocardial protection, sufficient angiogenesis, and improvement in cardiac function.

Effects and Mechanisms of Taohong Siwu Decoction on the Prevention and Treatment of Myocardial Injury.

Taohong Siwu decoction (THSWD) is one of the classic prescriptions for promoting blood circulation and removing blood stasis. With the continuous in-depth excavation in basic and clinical research, it has been found that THSWD has made greater progress in the prevention and treatment of cardiovascular diseases. Mechanisms of the current studies have shown that it could prevent and treat the myocardial injury by inhibiting inflammatory reaction, antioxidant stress, inhibiting platelet aggregation, prolonging clotting time, anti-fibrosis, reducing blood lipids, anti-atherosclerosis, improving hemorheology and vascular pathological changes, regulating related signal pathways and other mechanisms to prevent and treat the myocardial injury, so as to protect cardiomyocytes and improve cardiac function. Many clinical studies have shown that THSWD is effective in the prevention and treatment of cardiovascular diseases related to myocardial injuries, such as coronary heart disease angina pectoris (CHD-AP), and myocardial infarction. In clinical practice, it is often used by adding and subtracting prescriptions, the combination of compound prescriptions and combinations of chemicals and so on. However, there are some limitations and uncertainties in both basic and clinical research of prescriptions. According to the current research, although the molecular biological mechanism of various active ingredients needs to be further clarified, and the composition and dose of the drug have not been standardized and quantified, this study still has exploration for scientific research and clinical practice. Therefore, this review mainly discusses the basic mechanisms and clinical applications of THSWD in the prevention and treatment of the myocardial injury caused by CHD-AP and myocardial infarction. The authors hope to provide valuable ideas and references for researchers and clinicians.

Intervention effects of traditional Chinese medicine on stem cell therapy of myocardial infarction.

Cardiovascular diseases are the leading cause of global mortality, in which myocardial infarction accounts for 46% of total deaths. Although good progress has been achieved in medication and interventional techniques, a proven method to repair the damaged myocardium has not yet been determined. Stem cell therapy for damaged myocardial repair has evolved into a promising treatment for ischemic heart disease. However, low retention and poor survival of the injected stem cells are the major obstacles to achieving the intended therapeutic effects. Chinese botanical and other natural drug substances are a rich source of effective treatment for various diseases. As such, numerous studies have revealed the role of Chinese medicine in stem cell therapy for myocardial infarction treatment, including promoting proliferation, survival, migration, angiogenesis, and differentiation of stem cells. Here, we discuss the potential and limitations of stem cell therapy, as well as the regulatory mechanism of Chinese medicines underlying stem cell therapy. We focus on the evidence from pre-clinical trials and clinical practices, and based on traditional Chinese medicine theories, we further summarize the mechanisms of Chinese medicine treatment in stem cell therapy by the commonly used prescriptions. Despite the pre-clinical evidence showing that traditional Chinese medicine is helpful in stem cell therapy, there are still some limitations of traditional Chinese medicine therapy. We also systematically assess the detailed experimental design and reliability of included pharmacological research in our review. Strictly controlled animal models with multi-perspective pharmacokinetic profiles and high-grade clinical evidence with multi-disciplinary efforts are highly demanded in the future.

Exosome-Mediated miR-21 Was Involved in the Promotion of Structural and Functional Recovery Effect Produced by Electroacupuncture in Sciatic Nerve Injury.

PURPOSE: Our study is aimed at investigating the mechanism by which electroacupuncture (EA) promoted nerve regeneration by regulating the release of exosomes and exosome-mediated miRNA-21 (miR-21) transmission. Furthermore, the effects of Schwann cells- (SC-) derived exosomes on the overexpression of miR-21 for the treatment of PNI were investigated. METHODS: A sciatic nerve injury model of rat was constructed, and the expression of miR-21 in serum exosomes and damaged local nerves was detected using RT-qPCR after EA treatment. The exosomes were identified under a transmission electron microscope and using western blotting analysis. Then, the exosome release inhibitor, GW4869, and the miR-21-5p-sponge used for the knockdown of miR-21 were used to clarify the effects of exosomal miR-21 on nerve regeneration promoted by EA. The nerve conduction velocity recovery rate, sciatic nerve function index, and wet weight ratio of gastrocnemius muscle were determined to evaluate sciatic nerve function recovery. SC proliferation and the level of neurotrophic factors were assessed using immunofluorescence staining, and the expression levels of SPRY2 and miR-21 were detected using RT-qPCR analysis. Subsequently, the transmission of exosomal miR-21 from SC to the axon was verified in vitro. Finally, the exosomes derived from the SC infected with the miR-21 overexpression lentivirus were collected and used to treat the rat SNI model to explore the therapeutic role of SC-derived exosomes overexpressing miR-21. RESULTS: We found that EA inhibited the release of serum exosomal miR-21 in a PNI model of rats during the early stage of PNI, while it promoted its release during later stages. EA enhanced the accumulation of miR-21 in the injured nerve and effectively promoted the recovery of nerve function after PNI. The treatment effect of EA was attenuated when the release of circulating exosomes was inhibited or when miR-21 was downregulated in local injury tissue via the miR-21-5p-sponge. Normal exosomes secreted by SC exhibited the ability to promote the recovery of nerve function, while the overexpression of miR-21 enhanced the effects of the exosomes. In addition, exosomal miR-21 secreted by SC could promote neurite outgrowth in vitro. CONCLUSION: Our results demonstrated the mechanism of EA on PNI from the perspective of exosome-mediated miR-21 transport and provided a theoretical basis for the use of exosomal miR-21 as a novel strategy for the treatment of PNI.

Schwann cells-derived exosomal miR-21 participates in high glucose regulation of neurite outgrowth.

As a common complication of diabetes, the pathogenesis of diabetic peripheral neuropathy (DPN) is closely related to high glucose but has not been clarified. Exosomes can mediate crosstalk between Schwann cells (SC) and neurons in the peripheral nerve. Herein, we found that miR-21 in serum exosomes from DPN rats was decreased. SC proliferation was inhibited, cell apoptosis was increased, and the expression of miR-21 in cells and exosomes was downregulated when cultured in high glucose. Increasing miR-21 expression reversed these changes, while knockdown of miR-21 led to the opposite results. When co-cultured with exosomes derived from SC exposed to high glucose, neurite outgrowth was inhibited. On the contrary, neurite outgrowth was accelerated when incubated with exosomes rich in miR-21. We further demonstrated that the SC-derived exosomal miR-21 participates in neurite outgrowth probably through the AKT signaling pathway. Thus, SC-derived exosomal miR-21 contributes to high glucose regulation of neurite outgrowth.