Repair mechanisms of bone marrow mesenchymal stem cells in myocardial infarction

Scientometric analysis of evolution in sex-specific MSC therapy for cardiovascular diseases

BACKGROUND

Mesenchymal stem cell (MSC) therapy for cardiovascular diseases has shown promise; however, sex-specific differences remain understudied. This scientometric analysis provides the first comprehensive overview of sex-specific differences in mesenchymal stem cell (MSC) therapy for cardiovascular diseases, spanning from 1947 to 2024.

METHODS

We analyzed 61,029 publications using advanced bibliometric tools to identify research hotspots, publication trends, and collaborative networks.

RESULTS

A significant shift in research focus has been observed in the field of mesenchymal stem cell (MSC) therapy for cardiovascular diseases, transitioning from broad cardiovascular concepts in the 20th century to specialized sex-specific considerations in the 21st century. Furthermore, in the 21st-century research landscape, the formation of two distinct clusters for "male" and "female" in VOSviewer-generated network visualizations is highly important, emphasizing the growing recognition of sex-specific differences in MSC therapy responses and outcomes. This shift was accompanied by a marked increase in terminology related to sex-specific differences, with keywords like "genetic association" and "body mass index" forming distinct clusters in recent years.

CONCLUSIONS

This analysis underscores the critical need for sex-specific considerations in MSC therapy for cardiovascular disease. The emergence of distinct male and female clusters in research networks emphasizes the importance of tailoring approaches based on sex differences. Key areas identified for future investigation include the role of epigenetics in mediating sex-specific effects and the potential of sex-matched MSC-derived exosomes. These findings pave the way for more effective and personalized approaches in cardiovascular regenerative medicine, potentially leading to improved outcomes through sex-specific therapeutic strategies.

Fetal adnexa-derived allogeneic mesenchymal stem cells for cardiac regeneration: the future trend of cell-based therapy for age-related adverse conditions

Heart failure is known as the leading cause of mortality and morbidity in adults, not only in USA but worldwide. Since the world's population is aging, the burden of cardiovascular disorders is increasing. Mesenchymal stem/stromal cells (MSCs) from a patient's bone marrow or other tissues have been widely used as the primary source of stem cells for cellular cardiomyoplasty. The incongruencies that exist between various cell-therapy approaches for cardiac diseases could be attributed to variations in cell processing methods, quality of the process, and cell donors. Off-the-shelf preparations of MSCs, enabled by batch processing of the cells and controlled cell processing factories in regulated facilities, may offer opportunities to overcome these problems. In this study, for the first time, we focused on the fetal membranes and childbirth byproducts as a promising source of cells for regenerative medicine. While many studies have described the advantages of cells derived from these organs, their advantage as a source of younger cells has not been sufficiently covered by the literature. Thus, herein, we highlight challenges that may arise from the impairment of the regenerative capacity of MSCs due to donor age and how allograft cells from fetal adnexa can be a promising substitute for the aged patients' stem cells for myocardial regeneration. Moreover, obstacles to the use of off-the-shelf cell-therapy preparations in regenerative medicine are briefly summarized here.

Innovative Therapeutic Strategies for Myocardial Infarction Across Various Stages: Non-Coding RNA and Stem Cells

Myocardial infarction (MI) is a highly challenging and fatal disease, with diverse challenges arising at different stages of its progression. As such, non-coding RNAs (ncRNAs), which can broadly regulate cell fate, and stem cells with multi-differentiation potential are emerging as novel therapeutic approaches for treating MI across its various stages. NcRNAs, including microRNAs (miRNAs) and long non-coding RNAs (LncRNAs), can directly participate in regulating intracellular signaling pathways, influence cardiac angiogenesis, and promote the repair of infarcted myocardium. Currently, stem cells commonly used in medicine, such as mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPSCs), can differentiate into various human cell types without ethical concerns. When combined with ncRNAs, these stem cells can more effectively induce directed differentiation, promote angiogenesis in the infarcted heart, and replenish normal cardiac cells. Additionally, stem cell-derived exosomes, which contain various ncRNAs, can improve myocardial damage in the infarcted region through paracrine mechanisms. However, our understanding of the specific roles and mechanisms of ncRNAs, stem cells, and exosomes secreted by stem cells during different stages of MI remains limited. Therefore, this review systematically categorizes the different stages of MI, aiming to summarize the direct regulatory effects of ncRNAs on an infarcted myocardium at different points of disease progression. Moreover, it explores the specific roles and mechanisms of stem cell therapy and exosome therapy in this complex pathological evolution process. The objective of this review was to provide novel insights into therapeutic strategies for different stages of MI and open new research directions for the application of stem cells and ncRNAs in the field of MI repair.

Innovative hydrogel-based therapies for ischemia-reperfusion injury： bridging the gap between pathophysiology and treatment

Ischemia-reperfusion injury (IRI) commonly occurs in clinical settings, particularly in medical practices such as organ transplantation, cardiopulmonary resuscitation, and recovery from acute trauma, posing substantial challenges in clinical therapies. Current systemic therapies for IRI are limited by poor drug targeting, short efficacy, and significant side effects. Owing to their exceptional biocompatibility, biodegradability, excellent mechanical properties, targeting capabilities, controlled release potential, and properties mimicking the extracellular matrix (ECM), hydrogels not only serve as superior platforms for therapeutic substance delivery and retention, but also facilitate bioenvironment cultivation and cell recruitment, demonstrating significant potential in IRI treatment. This review explores the pathological processes of IRI and discusses the roles and therapeutic outcomes of various hydrogel systems. By categorizing hydrogel systems into depots delivering therapeutic agents, scaffolds encapsulating mesenchymal stem cells (MSCs), and ECM-mimicking hydrogels, this article emphasizes the selection of polymers and therapeutic substances, and details special crosslinking mechanisms and physicochemical properties, as well as summarizes the application of hydrogel systems for IRI treatment. Furthermore, it evaluates the limitations of current hydrogel treatments and suggests directions for future clinical applications.

Mesenchymal Stem Cell-Derived Exosomes and Their MicroRNAs in Heart Repair and Regeneration

Mesenchymal stem cells (MSCs) can be differentiated into cardiac, endothelial, and smooth muscle cells. Therefore, MSC-based therapeutic approaches have the potential to deal with the aftermaths of cardiac diseases. However, transplanted stem cells rarely survive in damaged myocardium, proposing that paracrine factors other than trans-differentiation may involve in heart regeneration. Apart from cytokines/growth factors, MSCs secret small, single-membrane organelles named exosomes. The MSC-secreted exosomes are enriched in lipids, proteins, nucleic acids, and microRNA (miRNA). There has been an increasing amount of data that confirmed that MSC-derived exosomes and their active molecule microRNA (miRNAs) regulate signaling pathways involved in heart repair/regeneration. In this review, we systematically present an overview of MSCs, their cardiac differentiation, and the role of MSC-derived exosomes and exosomal miRNAs in heart regeneration. In addition, biological functions regulated by MSC-derived exosomes and exosomal-derived miRNAs in the process of heart regeneration are reviewed.

BMSCs-derived Exosome CISH Alleviates Myocardial Infarction by Inactivating the NF-κB Pathway to Stimulate Macrophage M2 Polarization

Current myocardial infarction (MI) treatments are suboptimal, necessitating deeper pathogenesis understanding of MI. This research explored how exosomes (Exo) derived from bone marrow mesenchymal stem cells (BMSCs) contribute to MI mitigation and their therapeutic potential. Isolated BMSCs was identified by microscope, flow cytometry, alizarin red and oil red O staining. Exo were identified by TEM, NTA and western blot. HE staining, masson staining, and cardiac function parameters were used to assess the cardiac function in MI mice. TUNEL staining, western blot and qRT-PCR were used to detect apoptosis, inflammatory factors and M1/M2 markers. The NF-κB pathway activation was detected through western blot assays. Immunofluorescence, qRT-PCR, western blot, and flow cytometry were employed to evaluate macrophage polarization. MI mice showed cardiac injury, increased apoptosis and inflammation, while BMSCs-Exo treatment alleviated these effects. In MI mice, the macrophage M1 polarization was increased and the NF-κB pathway was activated, whereas BMSCs-Exo treatment reversed these changes. Furthermore, CISH expression was reduced in MI mice, but was elevated with BMSCs-Exo treatment. In vitro, LPS shifted RAW264.7 cells to M1 phenotype and activated the NF-κB pathway, yet BMSCs-Exo shifted them to M2 phenotype and inhibited the NF-κB pathway. Mechanistically, BMSCs-Exo induced macrophage M2 polarization by transmitting CISH to inhibit NF-κB activation. BMSCs-Exo mitigates MI by transmitting CISH to inhibit the NF-κB pathway, promoting macrophages to M2 type. This implies BMSCs-Exo could be a useful treatment for MI, and CISH could be a potential therapy target.

Exoskeleton Partial-Coated Stem Cells for Infarcted Myocardium Restoring

The integration of abiotic materials with live cells has emerged as an exciting strategy for the control of cellular functions. Exoskeletons consisting ofmetal-organic frameworks are generated to produce partial-coated bone marrow stem cells (BMSCs) to overcome low cell survival leading to disappointing effects for cell-based cardiac therapy. Partially coated exoskeletons can promote the survival of suspended BMSCs by integrating the support of exoskeletons and unimpaired cellular properties. In addition, partial exoskeletons exhibit protective effects against detrimental environmental conditions, including reactive oxygen species, pH changes, and osmotic pressure. The partial-coated cells exhibit increased intercellular adhesion forces to aggregate and adhere, promoting cell survival and preventing cell escape during cell therapy. The exoskeletons interact with cell surface receptors integrin α5β1, leading to augmented biological functions with profitable gene expression alteration, such as Vegfa, Cxcl12, and Adm. The partial-coated BMSCs display enhanced cell retention in infarcted myocardium through non-invasive intravenous injections. The repair of myocardial infarction has been achieved with improved cardiac function, myocardial angiogenesis, proliferation, and inhibition of cell apoptosis. This discovery advances the elucidation of potential molecular and cellular mechanisms for cell-exoskeleton interactions and benefits the rational design and manufacture of next-generation nanobiohybrids.

Mechanisms and Optimization Strategies of Paracrine Exosomes from Mesenchymal Stem Cells in Ischemic Heart Disease

The morbidity and mortality of myocardial infarction (MI) are increasing worldwide. Mesenchymal stem cells (MSCs) are multipotent stem cells with self-renewal and differentiation capabilities that are essential in tissue healing and regenerative medicine. However, the low implantation and survival rates of transplanted cells hinder the widespread clinical use of stem cells. Exosomes are naturally occurring nanovesicles that are secreted by cells and promote the repair of cardiac function by transporting noncoding RNA and protein. In recent years, MSC-derived exosomes have been promising cell-free treatment tools for improving cardiac function and reversing cardiac remodeling. This review describes the biological properties and therapeutic potential of exosomes and summarizes some engineering approaches for exosomes optimization to enhance the targeting and therapeutic efficacy of exosomes in MI.

Bone marrow mesenchymal stromal cell-derived small extracellular vesicles: A novel therapeutic agent in ischemic heart diseases

Myocardial injury is a major pathological factor that causes death in patients with heart diseases. In recent years, mesenchymal stromal cells (MSCs) have been generally used in treating many diseases in animal models and clinical trials. mesenchymal stromal cells have the ability to differentiate into osteocytes, adipocytes and chondrocytes. Thus, these cells are considered suitable for cardiac injury repair. However, mechanistic studies have shown that the secretomes of mesenchymal stromal cells, mainly small extracellular vesicles (sEVs), have better therapeutic effects than mesenchymal stromal cells themselves. In addition, small extracellular vesicles have easier quality control characteristics and better safety profiles. Therefore, mesenchymal stromal cell-small extracellular vesicles are emerging as novel therapeutic agents for damaged myocardial treatment. To date, many clinical trials and preclinical experimental results have demonstrated the beneficial effects of bone marrow-derived mesenchymal stromal cells (BMMSCs) and bone marrow-derived mesenchymal stromal cells-small extracellular vesicles on ischemic heart disease. However, the validation of therapeutic efficacy and the use of tissue engineering methods require an exacting scientific rigor and robustness. This review summarizes the current knowledge of bone marrow-derived mesenchymal stromal cells- or bone marrow-derived mesenchymal stromal cells-small extracellular vesicle-based therapy for cardiac injury and discusses critical scientific issues in the development of these therapeutic strategies.

Exosomes secreted from bone marrow mesenchymal stem cells suppress cardiomyocyte hypertrophy through Hippo-YAP pathway in heart failure

Mesenchymal stem cells-derived exosomes (MSCs-exosomes) reportedly possess cardioprotective effects. This study investigated the therapeutic potential and mechanisms of MSCs-exosomes on heart failure (HF). H9c2 cells were used to establish a cardiomyocyte hypertrophy model by angiotensin II (Ang II) treatment. Isolated MSCs-exosomes were identified by transmission electron microscope and CD63 detection. Apoptosis rate was measured by terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) assay. Levels of inflammatory factors [interleukin (IL)-1β, IL-4, IL-6, and tumor necrosis factor (TNF)-α] and brain natriuretic peptide (BNP) were determined by ELISA. Expression of apoptosis-related proteins [Bax, B-cell lymphoma-2 (Bcl-2), and caspase 3] and Hippo-Yes-associated protein (YAP) pathway-related proteins [YAP, phosphor (p)-YAP, and tafazzin (TAZ)] was detected by western blotting. Cardiomyocyte hypertrophy of H9c2 cells induced by Ang II was ameliorated by MSCs-exosomes treatment. MSCs-exosomes downregulated Bax and caspase 3 levels and upregulated Bcl-2 level in Ang II-induced H9c2 cells. MSCs-exosomes also reduced the levels of BNP, IL-1β, IL-4, IL-6, and TNF-α in Ang II-induced H9c2 cells. Meanwhile, p-YAP was downregulated and TAZ was upregulated after MSCs-exosomes administration. In conclusion, MSCs-exosomes alleviate the apoptosis and inflammatory response of cardiomyocyte via deactivating Hippo-YAP pathway in HF.

Therapeutic Potential of Mesenchymal Stem Cells versus Omega n − 3 Polyunsaturated Fatty Acids on Gentamicin-Induced Cardiac Degeneration

This study compared the cardioprotective action of mesenchymal stem cells (MSCs) and PUFAs in a rat model of gentamicin (GM)-induced cardiac degeneration. Male Wistar albino rats were randomized into four groups of eight rats each: group I (control group), group II (gentamicin-treated rats receiving gentamicin intraperitoneally (IP) at dose of 100 mg/kg/day for 10 consecutive days), group III (gentamicin and PUFA group receiving gentamicin IP at dose of 100 mg/kg/day for 10 consecutive days followed by PUFAs at a dose of 100 mg/kg/day for 4 weeks), and group IV (gentamicin and MSC group receiving gentamicin IP at dose of 100 mg/kg/day followed by a single dose of MSCs (1 × 10⁶)/rat IP). Cardiac histopathology was evaluated via light and electron microscopy. Immunohistochemical detection of proliferating cell nuclear antigen (PCNA), caspase-3 (apoptosis), Bcl2, and Bax expression was performed. Moreover, cardiac malonaldehyde (MDA) content, catalase activity, and oxidative stress parameters were biochemically evaluated. Light and electron microscopy showed that both MSCs and PUFAs had ameliorative effects. Their actions were mediated by upregulating PCNA expression, downregulating caspase-3 expression, mitigating cardiac MDA content, catalase activity, and oxidative stress parameters. MSCs and PUFAs had ameliorative effects against gentamicin-induced cardiac degeneration, with MSCs showing higher efficacy compared to PUFAs.

Cardiac Cell Therapy for Heart Repair: Should the Cells Be Left Out?

Cardiovascular disease (CVD) is still the leading cause of death worldwide. Coronary artery occlusion, or myocardial infarction (MI) causes massive loss of cardiomyocytes. The ischemia area is eventually replaced by a fibrotic scar. From the mechanical dysfunctions of the scar in electronic transduction, contraction and compliance, pathological cardiac dilation and heart failure develops. Once end-stage heart failure occurs, the only option is to perform heart transplantation. The sequential changes are termed cardiac remodeling, and are due to the lack of endogenous regenerative actions in the adult human heart. Regenerative medicine and biomedical engineering strategies have been pursued to repair the damaged heart and to restore normal cardiac function. Such strategies include both cellular and acellular products, in combination with biomaterials. In addition, substantial progress has been made to elucidate the molecular and cellular mechanisms underlying heart repair and regeneration. In this review, we summarize and discuss current therapeutic approaches for cardiac repair and provide a perspective on novel strategies that holding potential opportunities for future research and clinical translation.

Analysis of mesenchymal stem cell proteomes in situ in the ischemic heart

Rationale: Cell therapy for myocardial infarction is promising but largely unsuccessful in part due to a lack of mechanistic understanding. Techniques enabling identification of stem cell-specific proteomes in situ in the injured heart may shed light on how the administered cells respond to the injured microenvironment and exert reparative effects.

Objective: To identify the proteomes of the transplanted mesenchymal stem cells (MSCs) in the infarcted myocardium, we sought to target a mutant methionyl-tRNA synthetase (MetRS^L274G) in MSCs, which charges azidonorleucine (ANL), a methionine analogue and non-canonical amino acid, to tRNA and subsequently to nascent proteins, permitting isolation of ANL-labeled MSC proteomes from ischemic hearts by ANL-alkyne based click reaction.

Methods and Results: Murine MSCs were transduced with lentivirus MetRS^L274G and supplemented with ANL; the ANL-tagged nascent proteins were visualized by bio-orthogonal non-canonical amino-acid tagging, spanning all molecular weights and by fluorescent non-canonical amino-acid tagging, displaying strong fluorescent signal. Then, the MetRS^L274G-transduced MSCs were administered to the infarcted or Sham heart in mice receiving ANL treatment. The MSC proteomes were isolated from the left ventricular protein lysates by click reaction at days 1, 3, and 7 after cell administration, identified by LC/MS. Among all identified proteins (in Sham and MI hearts, three time-points each), 648 were shared by all 6 groups, accounting for 82±5% of total proteins in each group, and enriched under mitochondrion, extracellular exosomes, oxidation-reduction process and poly(A) RNA binding. Notably, 26, 110 and 65 proteins were significantly up-regulated and 11, 28 and 19 proteins were down-regulated in the infarcted vs. Sham heart at the three time-points, respectively; these proteins are pronounced in the GO terms of extracellular matrix organization, response to stress and regulation of apoptotic process and in the KEGG pathways of complements and coagulation cascades, apoptosis, and regulators of actin cytoskeleton.

Conclusions: MetRS^L274G expression allows successful identification of MSC-specific nascent proteins in the infarcted hearts, which reflect the functional states, adaptive response, and reparative effects of MSCs that may be leveraged to improve cardiac repair.

miR-19a/19b-loaded exosomes in combination with mesenchymal stem cell transplantation in a preclinical model of myocardial infarction

Aim: We aimed to investigate the protection of exogenous miR-19a/19b with bone marrow-derived mesenchymal stem cell (BM-MSC) transplantation on cardiac function and inhibition of fibrosis in myocardial infarction (MI). Materials & methods: BM-MSC-derived exosomes were used to deliver miR-19a/19b (exo/miR-19a/19b) to the cultured cardiac HL-1 cells, and the apoptosis of cells were evaluated. Exo/miR-19a/19b and BM-MSCs were also transplanted to an in vivo MI mouse model. The recovery of cardiac function was assessed and the level of cardiac fibrosis was determined. Results: Exo/miR-19a/19b and MSCs reduced the area of cardiac fibrosis in the heart tissue in the mouse MI model. Using BM-MSC-derived exosomes as a vehicle, miR-19a/19b significantly suppressed the apoptosis of cardiac HL-1 cells. The combination of Exo/miR-19a/19b and MSC transplantation significantly enhanced the recovery of cardiac function and reduced cardiac fibrosis in the MI model. Conclusion: Our study provides an effective regenerative intervention strategy to attenuate the damage of MI.

The Role of Angiogenesis-Inducing microRNAs in Vascular Tissue Engineering

Angiogenesis is an important process in tissue repair and regeneration as blood vessels are integral to supply nutrients to a functioning tissue. In this review, the application of microRNAs (miRNAs) or anti-miRNAs that can induce angiogenesis to aid in blood vessel formation for vascular tissue engineering in ischemic diseases such as peripheral arterial disease and stroke, cardiac diseases, and skin and bone tissue engineering is discussed. Endothelial cells (ECs) form the endothelium of the blood vessel and are recognized as the primary cell type that drives angiogenesis and studied in the applications that were reviewed. Besides ECs, mesenchymal stem cells can also play a pivotal role in these applications, specifically, by secreting growth factors or cytokines for paracrine signaling and/or as constituent cells in the new blood vessel formed. In addition to delivering miRNAs or cells transfected/transduced with miRNAs for angiogenesis and vascular tissue engineering, the utilization of extracellular vesicles (EVs), such as exosomes, microvesicles, and EVs collectively, has been more recently explored. Proangiogenic miRNAs and anti-miRNAs contribute to angiogenesis by targeting the 3'-untranslated region of targets to upregulate proangiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor, and hypoxia-inducible factor-1 and increase the transduction of VEGF signaling through the PI3K/AKT and Ras/Raf/MEK/ERK signaling pathways such as phosphatase and tensin homolog or regulating the signaling of other pathways important for angiogenesis such as the Notch signaling pathway and the pathway to produce nitric oxide. In conclusion, angiogenesis-inducing miRNAs and anti-miRNAs are promising tools for vascular tissue engineering for several applications; however, future work should emphasize optimizing the delivery and usage of these therapies as miRNAs can also be associated with the negative implications of cancer.

Stem Cells for Treatment of Musculoskeletal Conditions - Orthopaedic/Sports Medicine Applications

A myriad of musculoskeletal conditions afflicts a vast number of the world's population from birth to death. Countless pathological diseases and traumatic injuries (acute and chronic) contribute to different human disabilities, causing a tremendous financial toll on the economy of healthcare. The medical field is continually searching for novel ways to combat orthopedically related conditions. The immediate goal is the restoration of anatomy then ultimately return of function in hopes of enhancing quality if not the quantity of life. Traditional methods involve surgical correction/reconstruction of skeletal deformities from fractures/soft tissue damage/ruptures or replacement/resection of degenerated joints. Modern research is currently concentrating on innovative procedures to replenish/restore the human body close to its original/natural state [1, 2].

Autologous CXCR4+ Hematopoietic Stem Cells Injected into the Scar Tissue of Chronic Myocardial Infarction Patients Normalizes Tissue Contractility and Perfusion

BACKGROUND

Chronic myocardial infarction (CMI), represents a public health and a financial burden. Since stem cell transplant is used to regenerate cardiac tissue after acute myocardial infarction.

AIM OF THE STUDY

To determine if autologous CXCR4 stem cells could restore damaged myocardial tissue in patients with CMI lesions.

METHODS

20 NYHA grade III male patients with CMI defined by clinical, biochemical, ECG and echocardiographic parameters were included. Patients were treated with G-CSF for 6 d before isolating their autologous stem cells from PBMCs. Cell phenotyping was done by cytofluorometry using monoclonal antibodies (anti-CXCR4, -CD34, -48, -117, -133, -Ki67, -SDF1 and CXCR4); CXCR4 cell subpopulations isolated by sorting were adjusted to 1 × 10⁸ cells by subpopulation and injected in a circular pattern into the cicatrix previously defined by echocardiography.

RESULTS

Patients were followed for 6 and 12 months. Six months after cell implant improvements in left ventricle ejection fraction (from 33-50%), stress rate values (from -3/-9% to -18/-22%), stress tests (from 4-12 METS), and the quantity of left ventricle affected segments (3-9) disappeared according to the G-SPECT images. 12 months evaluations did not show significant differences. Interestingly, 3 months after cell implant the ECG showed normal electrical activity in 9 patients whereas after 6 months it was normal in all the patients.

CONCLUSIONS

These results ratify that locally injected autologous CXCR4+ bone marrow-derived stem cells have a physiological and a clinical impact in patients with CMI.

Allogeneic umbilical cord-derived mesenchymal stem cell transplantation for treating chronic obstructive pulmonary disease: a pilot clinical study

Introduction

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. COPD results from chronic inflammation of the lungs. Current treatments, including physical and chemical therapies, provide limited results. Stem cells, particularly mesenchymal stem cells (MSCs), are used to treat COPD. Here, we evaluated the safety and efficacy of umbilical cord-derived (UC)-MSCs for treating COPD.

Methods

Twenty patients were enrolled, 9 at stage C and 11 at stage D per the Global Initiative for Obstructive Lung Disease (GOLD) classification. Patients were infused with 10⁶ cells/kg of expanded allogeneic UC-MSCs. All patients were followed for 6 months after the first infusion. The treatment end-point included a comprehensive safety evaluation, pulmonary function testing (PFT), and quality-of-life indicators including questionnaires, the 6-min walk test (6MWT), and systemic inflammation assessments. All patients completed the full infusion and 6-month follow-up.

Results

No infusion-related toxicities, deaths, or severe adverse events occurred that were deemed related to UC-MSC administration. The UC-MSC-transplanted patients showed a significantly reduced Modified Medical Research Council score, COPD assessment test, and number of exacerbations. However, the forced expiratory volume in 1 s, C-reactive protein, and 6MWT values were nonsignificantly reduced after treatment (1, 3, and 6 months) compared with those before the treatment.

Conclusion

Systemic UC-MSC administration appears to be safe in patients with moderate-to-severe COPD, can significantly improve their quality of life, and provides a basis for subsequent cell therapy investigations.

Trial registration

ISRCTN, ISRCTN70443938. Registered 06 July 2019

Mesenchymal stem cell-derived exosomes ameliorate cardiomyocyte apoptosis in hypoxic conditions through microRNA144 by targeting the PTEN/AKT pathway

Background

A growing body of evidence suggests that stem cell-derived exosomal microRNAs (miRNAs) could be a promising cardioprotective therapy in the context of hypoxic conditions. The present study aims to explore how miRNA-144 (miR-144), a miRNA contained in bone marrow mesenchymal stem cell (MSC)-derived exosomes, exerts a cardioprotective effect on cardiomyocyte apoptosis in the context of hypoxic conditions and identify the underlying mechanisms.

Methods

MSCs were cultured using the whole bone marrow adherent method. MSC-derived exosomes were isolated using the total exosome isolation reagent and confirmed by nanoparticle trafficking analysis as well as western blotting using TSG101 and CD63 as markers. The hypoxic growth conditions for the H9C2 cells were established using the AnaeroPack method. Treatment conditions tested included H9C2 cells pre-incubated with exosomes, transfected with miR-144 mimics or inhibitor, or treated with the PTEN inhibitor SF1670, all under hypoxic growth conditions. Cell apoptosis was determined by flow cytometry using 7-ADD and Annexin V together. The expression levels of the miRNAs were detected by real-time PCR, and the expression levels of AKT/p-AKT, Bcl-2, caspase-3, HIF-1α, PTEN, and Rac-1 were measured by both real-time PCR and western blotting.

Results

Exosomes were readily internalized by H9C2 cells after co-incubation for 12 h. Exosome-mediated protection of H9C2 cells from apoptosis was accompanied by increasing levels of p-AKT. MiR-144 was found to be highly enriched in MSC-derived exosomes. Transfection of cells with a miR-144 inhibitor weakened exosome-mediated protection from apoptosis. Furthermore, treatment of cells grown in hypoxic conditions with miR-144 mimics resulted in decreased PTEN expression, increased p-AKT expression, and prevented H9C2 cell apoptosis, whereas treatment with a miR-144 inhibitor resulted in increased PTEN expression, decreased p-AKT expression, and enhanced H9C2 cell apoptosis in hypoxic conditions. We also validated that PTEN was a target of miR-144 by using luciferase reporter assay. Additionally, cells treated with SF1670, a PTEN-specific inhibitor, resulted in increased p-AKT expression and decreased H9C2 cell apoptosis.

Conclusions

These findings demonstrate that MSC-derived exosomes inhibit cell apoptotic injury in hypoxic conditions by delivering miR-144 to cells, where it targets the PTEN/AKT pathway. MSC-derived exosomes could be a promising therapeutic vehicle to facilitate delivery of miRNA therapies to ameliorate ischemic conditions.

Electronic supplementary material

The online version of this article (10.1186/s13287-020-1563-8) contains supplementary material, which is available to authorized users.

miR-19a/19b improves the therapeutic potential of mesenchymal stem cells in a mouse model of myocardial infarction

Myocardial infarction (MI) is the cardiac emergency that may leads to myocardial necrosis. Mesenchymal stem cells (MSCs) could be used to induce myocardial differentiation. However, the efficiency remains low. The aim of this study is to explore whether miR-19a/19b could enhance the therapeutic potential of mesenchymal stem cells in MI. Myocardial infarction mouse model was established using coronary artery ligation. Cardiac functional recovery was detected by Masson's trichrome staining. Under hypoxic condition, miR-19a/19b expression levels decreased in bone marrow-derived MSCs (BM-MSCs). MiR-19a/19b suppressed the proliferation of MSCs under hypoxic condition. After cell engraftment, miR-19a/19b promoted survival of MSCs. Mechanically, miR-19a/19b inhibited inflammatory cells infiltration into myocardium cells. Moreover, MSCs-miR-19a/19b improves cardiac functional recovery in diabetic MI mice models. All the results indicated that miR-19a/19b improves the therapeutic potential of mesenchymal stem cells in a mouse model of myocardial infarction.

Substantial Overview on Mesenchymal Stem Cell Biological and Physical Properties as an Opportunity in Translational Medicine

Mesenchymal stem cells (MSC) have piqued worldwide interest for their extensive potential to treat a large array of clinical indications, their unique and controversial immunogenic and immune modulatory properties allowing ample discussions and debates for their possible applications. Emerging data demonstrating that the interaction of biomaterials and physical cues with MSC can guide their differentiation into specific cell lineages also provide new interesting insights for further MSC manipulation in different clinical applications. Moreover, recent discoveries of some regulatory molecules and signaling pathways in MSC niche that may regulate cell fate to distinct lineage herald breakthroughs in regenerative medicine. Although the advancement and success in the MSC field had led to an enormous increase in the amount of ongoing clinical trials, we still lack defined clinical therapeutic protocols. This review will explore the exciting opportunities offered by human and animal MSC, describing relevant biological properties of these cells in the light of the novel emerging evidence mentioned above while addressing the limitations and challenges MSC are still facing.

Exosomes derived from pro-inflammatory bone marrow-derived mesenchymal stem cells reduce inflammation and myocardial injury via mediating macrophage polarization

Exosomes are served as substitutes for stem cell therapy, playing important roles in mediating heart repair during myocardial infarction injury. Evidence have indicated that lipopolysaccharide (LPS) pre-conditioning bone marrow-derived mesenchymal stem cells (BMSCs) and their secreted exosomes promote macrophage polarization and tissue repair in several inflammation diseases; however, it has not been fully elucidated in myocardial infarction (MI). This study aimed to investigate whether LPS-primed BMSC-derived exosomes could mediate inflammation and myocardial injury via macrophage polarization after MI. Here, we found that exosomes derived from BMSCs, in both Exo and L-Exo groups, increased M2 macrophage polarization and decreased M1 macrophage polarization under LPS stimulation, which strongly depressed LPS-dependent NF-κB signalling pathway and partly activated the AKT1/AKT2 signalling pathway. Compared with Exo, L-Exo had superior therapeutic effects on polarizing M2 macrophage in vitro and attenuated the post-infarction inflammation and cardiomyocyte apoptosis by mediating macrophage polarization in mice MI model. Consequently, we have confidence in the perspective that low concentration of LPS pre-conditioning BMSC-derived exosomes may develop into a promising cell-free treatment strategy for clinical treatment of MI.

The impact of mesenchymal stem cells on doxorubicin-induced testicular toxicity and progeny outcome of male prepubertal rats

BACKGROUND

Many therapies to treat cancer are gonadotoxic and can lead to infertility. New strategies to diminish the side effects and protective plans during and after chemotherapy are needed. Therefore, bone marrow mesenchymal stem cells (BM-MSCs) as a novel solution were investigated against doxorubicin (Dox)-induced toxicity in rat testes.

METHODS

Forty male albino prepubertal rats were divided into four groups, 10 rats per each group. The first was injected intraperitoneally with saline as control. The second group was injected intravenously with a single dose of BM-MSCs (2 × 10⁶ cells). The third was injected intraperitoneally with a single dose of Dox (5 mg/kg b.wt). The fourth was injected with both Dox and BM-MSCs as previously mentioned. Rats were cohabited each separately with an untreated adult female after 8 weeks of treatment to examine Dox effects on male's fertility.

RESULTS

BM-MSCs counteract the deleterious effects of Dox on body, testicular weight as well as sperm quality by increasing sperm concentration and reducing the rate of abnormal sperm. BM-MSCs reduced significantly the testicular oxidative stress by reducing the elevated level of malondialdehyde and increasing the antioxidant capacity. Histologically, the testicular atrophy, severe damage of spermatogenesis and the significant reduction of the diameter and germinative cell layer thickness of the seminiferous tubules caused by Dox were significantly recovered after administration of the BM-MSCs.

CONCLUSION

BM-MSCs have a significant role in restoring the structural efficiency of male reproductive system in rats after Dox treatment.

Transplantation of CRISPRa system engineered IL10-overexpressing bone marrow-derived mesenchymal stem cells for the treatment of myocardial infarction in diabetic mice

Background

Myocardial infarction (MI) is a common cause of mortality in people. Mesenchymal stem cell (MSC) has been shown to exert therapeutic potential to treat myocardial infarction (MI). However, in patients with diabetes, the diabetic environment affected MSCs activity and could impair the efficacy of treatment. Interleukin-10 (IL-10) has been shown to attenuate MI by suppressing inflammation. In current study, the combination of MSC transplantation with IL-10 was evaluated in a diabetic mice model with MI.

Methods

We engineered bone marrow derived MSCs (BM-MSCs) to overexpress IL-10 by using CRISPR activation. We established the diabetic mice model with MI and monitored the IL-10 expression after BM-MSCs transplantation. We also evaluated the effects of BM-MSCs transplantation on inflammatory response, cell apoptosis, cardiac function and angiogenesis.

Results

CRISPR activation system enabled overexpression of IL-10 in BM-MSCs. Transplantation of BM-MSCs overexpressing IL-10 resulted in IL-10 expression in heart after transplantation. Transplantation of BM-MSCs overexpressing IL-10 inhibited inflammatory cell infiltration and pro-inflammatory cytokines production, improved cardiac functional recovery, alleviated cardiac injury, decreased apoptosis of cardiac cells and increased angiogenesis.

Conclusion

In summary, we have demonstrated the therapeutic potential of IL-10 overexpressed BM-MSCs in the treatment of MI in diabetic mice.

Production of Mesenchymal Stem Cells Through Stem Cell Reprogramming

Mesenchymal stem cells (MSCs) possess a broad spectrum of therapeutic applications and have been used in clinical trials. MSCs are mainly retrieved from adult or fetal tissues. However, there are many obstacles with the use of tissue-derived MSCs, such as shortages of tissue sources, difficult and invasive retrieval methods, cell population heterogeneity, low purity, cell senescence, and loss of pluripotency and proliferative capacities over continuous passages. Therefore, other methods to obtain high-quality MSCs need to be developed to overcome the limitations of tissue-derived MSCs. Pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), are considered potent sources for the derivation of MSCs. PSC-derived MSCs (PSC-MSCs) may surpass tissue-derived MSCs in proliferation capacity, immunomodulatory activity, and in vivo therapeutic applications. In this review, we will discuss basic as well as recent protocols for the production of PSC-MSCs and their in vitro and in vivo therapeutic efficacies. A better understanding of the current advances in the production of PSC-MSCs will inspire scientists to devise more efficient differentiation methods that will be a breakthrough in the clinical application of PSC-MSCs.

Differential roles of microtubules in the two formation stages of membrane nanotubes between human mesenchymal stem cells and neonatal mouse cardiomyocytes

Membrane nanotubes (MNTs) are a kind of novel way for communication between two distant cells. It was recently shown that MNTs can be formed between distressed cardiomyocytes (CMs) and mesenchymal stem cells (MSCs). As a cytoskeleton-containing structure, the role of microtubules in MNTs is not fully understood. Here, we investigated this question. By membrane dye staining, we found that the numbers of MNTs between human MSCs (hMSCs) and distressed neonatal mouse CMs (NMCMs) increased gradually from 3 to 16 h and remained constant from 16 to 30 h, which were identified as active formation stage (the 1st stage, ≤16 h in coculture), and mature and stable stage (the 2nd stage, >16 h in coculture), respectively. In the 1st stage, more MNTs originated from hMSCs, whereas more MNTs originated from NMCMs in the 2nd stage. The formation of MNTs was affected when microtubules were disrupted by nocodazole in the 1st stage, but not in the 2nd stage. MNTs became shorter and thinner when microtubules were disrupted in the 2nd stage. Immunofluorescence staining and flow cytometry showed that mitochondria in hMSCs were transported into distressed NMCMs, which was suppressed by nocodazole in the 2nd stage. Tunnel staining showed that hypoxia/reoxygenation-induced apoptosis of NMCMs only in the 2nd stage could be rescued by direct, but not indirect, coculture with hMSCs. This rescue function was weakened when the mitochondrial functions of cocultured hMSCs were disrupted by EtBr or microtubules in cocultures were disrupted by nocodazole. All these results suggested that there are two stages for MNT formation, and microtubules played differential roles in the two stages: During the 1st stage, microtubules were required for MNT formation, whereas during the 2nd stage, microtubules were related to the morphological features of MNTs and played a key role in anti-apoptosis of MNTs by mitochondrial transfer.

Prevascularized mesenchymal stem cell-sheets increase survival of random skin flaps in a nude mouse model

A random skin flap is commonly applied in plastic and reconstructive surgery. The distal part of the random skin flap often risks necrosis because the blood flow may be compromised. Prevascularization is a widely used technology to intensify the vascularization function of biomaterials. In fact, human mesenchymal stem cell (hMSC) sheets promote neoangiogenesis. We speculated that prevascularized hMSC cell sheets (PHCS) would further improve neovascularization by producing more angiogenic growth factors in a random skin flap animal model. In this study, PHCS were set up by co-culturing human umbilical vein endothelial cells (HUVECs) with hMSC cell sheets (HCS). In vitro, we observed microvessel formation and significantly increased production of angiogenesis-related factors. Thus, we analyzed the microvessel networks, vascular maturation, and angiogenic growth factors of the cell sheet. In vivo, PHCS and HCS were implanted in a murine ischemic random skin flap model. Implanted PHCS significantly increased blood perfusion and improved skin flap survival when compared to untreated control skin flaps. The survival rate of the prevascularized and control skin flaps was assessed after 3, 5, and 7 days via analysis of macroscopic images and Laser Doppler Perfusion Imaging (LDPI). Additionally, the numbers of skin appendages, collagen fibers deposition, and epidermal thickness were evaluated. Moreover, the PHCS group also induced the most intense neovascularization, the upshot of which was a robust blood microcirculation supporting skin flap survival. Therefore, PHCS implantation can effectively enhance local neoangiogenesis and hence increase the survival of otherwise ischemic skin flaps. Hence, local administration of PHCS may serve as an alternative approach in improving random skin flap survival.

Follistatin-like 1 protects mesenchymal stem cells from hypoxic damage and enhances their therapeutic efficacy in a mouse myocardial infarction model

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.

Current Strategies to Generate Human Mesenchymal Stem Cells In Vitro

Mesenchymal stem cells (MSCs) are heterogeneous multipotent stem cells that are involved in the development of mesenchyme-derived evolving structures and organs during ontogeny. In the adult organism, reservoirs of MSCs can be found in almost all tissues where MSCs contribute to the maintenance of organ integrity. The use of these different MSCs for cell-based therapies has been extensively studied over the past years, which highlights the use of MSCs as a promising option for the treatment of various diseases including autoimmune and cardiovascular disorders. However, the proportion of MSCs contained in primary isolates of adult tissue biopsies is rather low and, thus, vigorous ex vivo expansion is needed especially for therapies that may require extensive and repetitive cell substitution. Therefore, more easily and accessible sources of MSCs are needed. This review summarizes the current knowledge of the different strategies to generate human MSCs in vitro as an alternative method for their applications in regenerative therapy.

Effects of different doses of granulocyte colony-stimulating factor mobilization therapy on ischemic cardiomyopathy

G-CSF mobilization might be beneficial to ICM, but the relationship between effect/safety and the dosage of G-CSF remains unclear. In this study, 24 pigs were used to build ICM models and were randomized into four groups. Four weeks later, different dosages of G-CSF were given daily by subcutaneous injection for 5 days. Another 4 weeks later, all the animals were sacrificed. Electrocardiography, coronary arteriography, left ventriculography, transthoracic echocardiography, cardiac MRI, and SPECT, histopathologic analysis, and immunohistochemistry techniques were used to evaluate left ventricular function and myocardial infarct size. Four weeks after G-CSF treatment, pigs in middle-dose G-CSF group exhibited obvious improvements of left ventricular remodeling and function. Moderate G-CSF mobilization ameliorated the regional contractility of ICM, preserved myocardial viability, and reduced myocardial infarct size. More neovascularization and fewer apoptotic myocardial cells were observed in the ischemic region of the heart in middle-dose group. Expression of vWF, VEGF and MCP-1 were up-regulated, and Akt1 was activated in high- and middle-dose groups. Moreover, CRP, TNF-α and S-100 were elevated after high-dose G-CSF mobilization. Middle-dose G-CSF mobilization therapy is an effective and safe treatment for ICM, and probably acts via a mechanism involving promoting neovascularization, inhibiting cardiac fibrosis and anti-apoptosis.

Concise Review: Optimized Strategies for Stem Cell-Based Therapy in Myocardial Repair: Clinical Translatability and Potential Limitation

Ischemic heart diseases (IHDs) remain major public health problems with high rates of morbidity and mortality worldwide. Despite significant advances, current therapeutic approaches are unable to rescue the extensive and irreversible loss of cardiomyocytes caused by severe ischemia. Over the past 16 years, stem cell-based therapy has been recognized as an innovative strategy for cardiac repair/regeneration and functional recovery after IHDs. Although substantial preclinical animal studies using a variety of stem/progenitor cells have shown promising results, there is a tremendous degree of skepticism in the clinical community as many stem cell trials do not confer any beneficial effects. How to accelerate stem cell-based therapy toward successful clinical application attracts considerate attention. However, many important issues need to be fully addressed. In this Review, we have described and compared the effects of different types of stem cells with their dose, delivery routes, and timing that have been routinely tested in recent preclinical and clinical findings. We have also discussed the potential mechanisms of action of stem cells, and explored the role and underlying regulatory components of stem cell-derived secretomes/exosomes in myocardial repair. Furthermore, we have critically reviewed the different strategies for optimizing both donor stem cells and the target cardiac microenvironments to enhance the engraftment and efficacy of stem cells, highlighting their clinical translatability and potential limitation. Stem Cells 2018;36:482-500.

Inhibition of mircoRNA-34a Enhances Survival of Human Bone Marrow Mesenchymal Stromal/Stem Cells Under Oxidative Stress

BACKGROUND Mesenchymal stromal/stem cells (MSCs) are broadly used for many diseases, but the efficacy of MSC engraftment is very low due to low viability and high cell death rate under a stressful microenvironment. The present study aimed to investigate whether microRNA-34a (miR-34a), which is a downstream target of P53, is involved in H2O2-induced MSC cell death. MATERIAL AND METHODS Human bone marrow MSCs (hMSCs) were purchased from Lonza and were cultured as previously described. hMSCs were transfected with miR-34a inhibitor and exposed to H2O2. Cell proliferation assay was used to assess the survival rate of hMSCs. Real-time PCR and Western blot analysis were used to examine proliferation and survival ability of hMSCs. RESULTS H2O2 exposure significantly increased miR-34a expression in human bone marrow MSCs. H2O2 challenge induced massive MSC cell death along with reduction of expression of proliferation marker Ki67 and survival-related genes Bcl-2 and Survivin. Transfection of miR-34a inhibitor anti-34a led to a significant protective effect and rescued MSC cell death triggered by H2O2 exposure by 50%. Moreover, anti-34a dramatically increased Bcl-2 and Ki67 mRNA expression levels by over 10-fold compared to the mock control group under H2O2 exposure. The protein levels of Bcl-2 and Survivin were also rescued by anti-34a treatment by 50%. CONCLUSIONS Our results suggest that miR-34a plays a key role in oxidative stress-induced MSC cell death, and targeting miR-34a might be a promising strategy to enhance the survival rate of engrafted stem cells, which may improve therapeutic outcome.

Morphological and functional changes in bone marrow mesenchymal stem cells in rats with heart failure

The changes in bone marrow-derived mesenchymal stem cells (BMSCs), in terms of cell morphology and protein expression in rats with heart failure, were studied. Pressure overload chronic heart failure rat model was induced with partial constriction of the abdominal aorta. BMSCs from the model and the sham operation groups were isolated and cultured (cell density, 10⁸ cells/l), and supernatant was collected after 72 h. Enzyme-linked immunosorbent assay was used to measure HGF, IGF-1, PDGF, SCF, FGF and VEGF levels in the supernatant. Results showed that in the model group, the minimum cell diameter, the average cell area and the protein expression in single BMSCs were significantly less than those in the sham operation group. In the model group, SCF and PDGF levels were significantly lower than those in the sham operation group. VEGF concentration in the model group was significantly higher than that in the sham operation group. Compared with normal rats, the morphology of BMSCs in rats with heart failure changed considerably, the protein expression of a single cell and the ability to secrete cytokines decreased in a meaningful way.

Apelin promotes mesenchymal stem cells survival and vascularization under hypoxic-ischemic condition in vitro involving the upregulation of vascular endothelial growth factor

BACKGROUND

Mesenchymal stem cells (MSCs) transplantation has been regarded as an optimal therapeutic approach for cardiovascular disease. However, the inferior survival and low vascularization potential of these cells in the local infarct site reduce the therapeutic efficacy. In this study, we investigated the influence of apelin on MSCs survival and vascularization under hypoxic-ischemic condition in vitro and explored the relevant mechanism.

METHODS

MSCs were obtained from C57BL/6 mice and cultured in vitro. Cells of the third passage were divided into MSCs and MSCs+apelin groups. In the MSCs+apelin group, MSCs were stimulated with apelin-13 (5μM). The two groups experienced exposure to hypoxia (1% O₂) and serum deprivation for 24h, using normoxia (20% O₂) as a negative control during the process. Human umbilical vein endothelial cells (HUVECs) were used and incubated with conditioned media from both groups to promote vascularization for another 6h. Vascular densities were assessed and relevant biomarkers were detected thereafter.

RESULTS

Compared with MSCs group, MSCs+apelin group presented more rapid growth. The proliferation rate was much higher. Cells apoptosis percentage was significantly declined both under normoxic and hypoxic conditions. Media produced from MSCs+apelin group triggered HUVECs to form a larger number of vascular branches on matrigel. The expression and secretion of vascular endothelial growth factor (VEGF) were significantly increased.

CONCLUSION

Apelin could effectively promote MSCs survival and vascularization under hypoxic-ischemic condition in vitro, and this procedure was associated with the upregulation of VEGF. This study provides a new perspective for exploring novel approaches to enhance MSCs survival and vascularization potential.

Intramuscular injection of human umbilical cord-derived mesenchymal stem cells improves cardiac function in dilated cardiomyopathy rats

Background

Stem cells provide a promising candidate for the treatment of the fatal pediatric dilated cardiomyopathy (DCM). This study aimed to investigate the effects of intramuscular injection of human umbilical cord-derived mesenchymal stem cells (hUCMSCs) on the cardiac function of a DCM rat model.

Methods

A DCM model was established by intraperitoneal injections of doxorubicin in Sprague-Dawley rats. hUCMSCs at different concentrations or cultured medium were injected via limb skeletal muscles, with blank medium injected as the control. The rats were monitored for 4 weeks, meanwhile BNP, cTNI, VEGF, HGF, GM-CSF, and LIF in the peripheral blood were examined by ELISA, and cardiac function was monitored by echocardiography (Echo-CG). Finally, the expression of IGF-1, HGF, and VEGF in the myocardium was examined by histoimmunochemistry and real-time PCR, and the ultrastructure of the myocardium was examined by electron microscopy.

Results

Injection of hUCMSCs markedly improved cardiac function in the DCM rats by significantly elevating left ventricular ejection fraction (LVEF) and left ventricular fraction shortening (LVFS). The BNP and cTNI levels in the peripheral blood were reduced by hUCMSCs, while HGF, LIF, GM-CSF, and VEGF were increased by hUCMSCs. Expression of IGF-1, HGF, and VEGF in the myocardium from the DCM rats was significantly increased by hUCMSC injection. Furthermore, hUCMSCs protected the ultrastructure of cardiomyocytes by attenuating mitochondrial swelling and maintaining sarcolemma integrity.

Conclusions

Intramuscular injection of UCMSCs can improve DCM-induced cardiac function impairment and protect the myocardium. These effects may be mediated by regulation of relevant cytokines in serum and the myocardium.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0472-y) contains supplementary material, which is available to authorized users.

Tracking stem cells with superparamagnetic iron oxide nanoparticles: perspectives and considerations

Superparamagnetic iron oxide nanoparticles (SPIONs) have been used for diagnoses in biomedical applications, due to their unique properties and their apparent safety for humans. In general, SPIONs do not seem to produce cell damage, although their long-term in vivo effects continue to be investigated. The possibility of efficiently labeling cells with these magnetic nanoparticles has stimulated their use to noninvasively track cells by magnetic resonance imaging after transplantation. SPIONs are attracting increasing attention and are one of the preferred methods for cell labeling and tracking in preclinical and clinical studies. For clinical protocol approval of magnetic-labeled cell tracking, it is essential to expand our knowledge of the time course of SPIONs after cell incorporation and transplantation. This review focuses on the recent advances in tracking SPION-labeled stem cells, analyzing the possibilities and limitations of their use, not only focusing on myocardial infarction but also discussing other models.

Chitosan hydrogel improves mesenchymal stem cell transplant survival and cardiac function following myocardial infarction in rats

Myocardial infarction (MI) remains the leading cause of cardiovascular-associated mortality and morbidity. Improving the retention rate, survival and cardiomyocyte differentiation of mesenchymal stem cells (MSCs) is important in improving the treatment of patients with MI. In the present study, temperature-responsive chitosan hydrogel, an injectable scaffold, was used to deliver MSCs directly into the infarcted myocardium of rats following MI. Histopathology and immunohistochemical staining were used to evaluate cardiac cell survival and regeneration, and cardiac function was assessed using an echocardiograph. It was demonstrated that chitosan hydrogel increased graft size and cell retention in the ischemic heart, promoted MSCs to differentiate into cardiomyocytes and increased the effects of MSCs on neovasculature formation. Furthermore, chitosan hydrogel enhanced the effect of MSCs on the improvement of cardiac function and hemodynamics in the infarcted area of rats following MI. These findings suggest that chitosan hydrogel is an appropriate material to deliver MSCs into infarcted myocardium.

Keratin mediated attachment of stem cells to augment cardiomyogenic lineage commitment

The objective of this work was to develop a simple surface modification technique using keratin derived from human hair for efficient cardiomyogenic lineage commitment of human mesenchymal stem cells (hMSCs). Keratin was extracted from discarded human hair containing both the acidic and basic components along with the heterodimers. The extracted keratin was adsorbed to conventional tissue culture polystyrene surfaces at different concentration. Keratin solution of 500μg/ml yielded a well coated layer of 12±1nm thickness with minimal agglomeration. The keratin coated surfaces promoted cell attachment and proliferation. Large increases in the mRNA expression of known cardiomyocyte genes such as cardiac actinin, cardiac troponin and β-myosin heavy chain were observed. Immunostaining revealed increased expression of sarcomeric α-actinin and tropomyosin whereas Western blots confirmed higher expression of tropomyosin and myocyte enhancer factor 2C in cells on the keratin coated surface than on the non-coated surface. Keratin promoted DNA demethylation of the Atp2a2 and Nkx2.5 genes thereby elucidating the importance of epigenetic changes as a possible molecular mechanism underlying the increased differentiation. A global gene expression analysis revealed a significant alteration in the expression of genes involved in pathways associated in cardiomyogenic commitment including cytokine and chemokine signaling, cell-cell and cell-matrix interactions, Wnt signaling, MAPK signaling, TGF-β signaling and FGF signaling pathways among others. Thus, adsorption of keratin offers a facile and affordable yet potent route for inducing cardiomyogenic lineage commitment of stem cells with important implications in developing xeno-free strategies in cardiovascular regenerative medicine.

Peroxisome Proliferator-Activated Receptor Gamma Promotes Mesenchymal Stem Cells to Express Connexin43 via the Inhibition of TGF-β1/Smads Signaling in a Rat Model of Myocardial Infarction

BACKGROUND

In this study, we hypothesized that activation of PPAR-γ enhanced MSCs survival and their therapeutic efficacy via upregulating the expression of Cx43.

METHODS

MI was induced in 50 male Sprague-Dawley rats. The rats were randomized into five groups: MI group and four intervention groups, including the MSCs group, combined therapy group (MSCs+ pioglitazone), pioglitazone group and PBS group. Two weeks later, 5 × 10(6) MSCs labeled with PKH26 in PBS were injected into the infarct anterior ventricular free wall in the MSCs and combined therapy groups, and PBS alone was injected into the infarct anterior ventricular free wall in the PBS group. Pioglitazone (3 mg/kg/day) was given to the combined therapy and pioglitazone groups by oral gavage at the same time for another 2 weeks. Myocardial function and relevant signaling molecules involved were all examined thereafter.

RESULTS

Heart function was enhanced after MSCs treatment for 2 weeks post MI. A significant improvement of heart function was observed in the combined therapy group in contrast to the other three intervention groups. Compared with the MSCs group, there was a higher level of PPAR-γ in the combined therapy group; Cx43 was remarkably increased in different regions of the left ventricle; TGF-β1 was decreased in the infarct zone and border zone. To the downstream signaling molecules, mothers against Smad proteins including Smad2 and Smad3 presented a synchronized alteration with TGF-β1; no differences of the expressions of ERK1/2 and p38 could be discovered in the left ventricular cardiac tissue.

CONCLUSIONS

MSCs transplantation combined with pioglitazone administration improved cardiac function more effectively after MI. Activation of PPAR-γ could promote MSCs to express Cx43. Inhibition of TGF-β1/Smads signaling pathway might be involved in the process.

Advances in the Use of Stem Cells in Veterinary Medicine: From Basic Research to Clinical Practice

Today, several veterinary diseases may be treated with the administration of stem cells. This is possible because these cells present a high therapeutic potential and may be injected as autologous or allogenic, freshly isolated, or previously cultured. The literature supports that the process is safe and brings considerable benefits to animal health. Knowledge about how adult stem cells modulate the molecular signals to activate cell homing has also been increasingly determined, evidencing the mechanisms which enable cells to repair and regenerate injured tissues. Preclinical studies were designed for many animal models and they have contributed to the translation to the human clinic. This review shows the most commonly used stem cell types, with emphasis on mesenchymal stem cells and their mechanistic potential to repair, as well as the experimental protocols, studied diseases, and species with the highest amount of studies and applications. The relationship between stem cell protocols utilized on clinics, molecular mechanisms, and the physiological responses may offer subsidies to new studies and therefore improve the therapeutic outcome for both humans and animals.

Mesenchymal stem cells in cardiac regeneration: a detailed progress report of the last 6 years (2010-2015)

Mesenchymal stem cells have been used for cardiovascular regenerative therapy for decades. These cells have been established as one of the potential therapeutic agents, following several tests in animal models and clinical trials. In the process, various sources of mesenchymal stem cells have been identified which help in cardiac regeneration by either revitalizing the cardiac stem cells or revascularizing the arteries and veins of the heart. Although mesenchymal cell therapy has achieved considerable admiration, some challenges still remain that need to be overcome in order to establish it as a successful technique. This in-depth review is an attempt to summarize the major sources of mesenchymal stem cells involved in myocardial regeneration, the significant mechanisms involved in the process with a focus on studies (human and animal) conducted in the last 6 years and the challenges that remain to be addressed.

Mast cells promote proliferation and migration and inhibit differentiation of mesenchymal stem cells through PDGF

BACKGROUND

Mast cells (MCs) dynamically participate in wound healing after myocardial infarction (MI) by releasing cytokines. Indeed, MC-deficient mice undergo rapid left ventricular dilation post-MI. Mesenchymal stem cells (MSCs) are recruited to the injured region following an MI and have potential for cardiac repair. In the current study, we evaluate the effect of MCs on MSC proliferation and myogenic differentiation.

METHODS AND RESULTS

MCs were cultured from mouse bone marrow and MC granulate (MCG) was extracted from MCs via freeze-thaw cycles followed by filtration. α-SMA (smooth muscle actin) expression was examined as an indicator of myogenic differentiation. MSC/MC co-culture resulted in decreased MSC differentiation indicated by α-SMA suppression in MSCs. MCG also suppressed α-SMA expression and increased MSC migration and proliferation in a dose-dependent manner. Removal of MCG rescued α-SMA expression and MSC differentiation. Platelet derived growth factor (PDGF) receptor blockade using AG1296 also rescued MSC differentiation even after MCG treatment. Real-time PCR and Western blot showed that MCG exerted its effects on MSCs via downregulation of miR-145 and miR-143, downregulation of myocardin, upregulation of Klf4, and increased Erk and Elk1 phosphorylation.

CONCLUSIONS

MCs promote MSC proliferation and migration by suppressing their myogenic differentiation. MCs accomplish this via activation of the PDGF pathway, downregulation of miR-145/143, and modulation of the myocardin-Klf4 axis. These data suggest a potential role for MSC/MC interaction in the infarcted heart where MCs may inhibit MSCs from differentiation and promote their proliferation whereby increased cardiac MSC accumulation promotes eventual cardiac regeneration after MCs cease activity.

Mesenchymal Stem Cells and Mononuclear Cells From Cord Blood: Cotransplantation Provides a Better Effect in Treating Myocardial Infarction

The aim of this study was to evaluate the effect of cotransplanting mononuclear cells from cord blood (CB-MNCs) and mesenchymal stem cells (MSCs) as treatment for myocardial infarction (MI). Transplanting CD34+ cells or MSCs separately has been shown effective in treating MI, but the effect of cotransplanting CB-MNCs and MSCs is not clear. In this study, MSCs were separated by their adherence to the tissue culture. The morphology, immunophenotype, and multilineage potential of MSCs were analyzed. CB-MNCs were separated in lymphocyte separation medium 1.077. CD34+ cell count and viability were analyzed by flow cytometry. Infarcted male Sprague-Dawley rats in a specific-pathogen-free grade were divided into four treatment groups randomly: group I, saline; group II, CB-MNCs; group III, MSCs; and group IV, CB-MNCs plus MSCs. The saline, and CB-MNCs and/or MSCs were injected intramyocardially in infarcted rats. Their cardiac function was evaluated by echocardiography. The myocardial capillary density was analyzed by immunohistochemistry. Both cell types induced an improvement in the left ventricular cardiac function and increased tissue cell proliferation in myocardial tissue and neoangiogenesis. However, CB-MNCs plus MSCs were more effective in reducing the infarct size and preventing ventricular remodeling. Scar tissue was reduced significantly in the CB-MNCs plus MSCs group. MSCs facilitate engraftment of CD34+ cells and immunomodulation after allogeneic CD34+ cell transplantation. Cotransplanting MSCs and CB-MNCs might be more effective than transplanting MSCs or CB-MNCs separately for treating MI. This study contributes knowledge toward effective treatment strategies for MI.