Intravenous injection of allogeneic umbilical cord-derived multipotent mesenchymal stromal cells reduces the infarct area and ameliorates cardiac function in a porcine model of acute myocardial infarction

The therapeutic efficacy comparison of MSCs derived different tissues unveilings anti-apoptosis more crucial than angiogenesis in treating acute myocardial infarction

BACKGROUND

Myocardial infarction (MI) is a severe disease that often associated with impaired angiogenesis and increased myocardial apoptosis. Mesenchymal stromal cells (MSCs) have been a promising candidate for treating myocardial infarction. However, functional heterogeneity of MSCs leads to inconsistent therapeutic efficiency and the current MSCs-based therapy lacks the concept and implementation of precision medicine. In this study, we compared the cardioprotective effect of UCMSCs and ADMSCs targeting the angiogenesis in a mouse MI model and screened out optimum MSCs candidate for precise clinical application.

METHODS

The gene expression profiles of UCMSCs and ADMSCs were investigated through RNA sequencing analysis. To compare their angiogenic potential, we performed tube formation assay, Matrigel plug assays, and aortic ring assay, and analyzed pro-angiogenic genes via qPCR. Subsequently, UCMSCs and ADMSCs were respectively injected into myocardium after MI surgery in mice. On day 28 post-MI, echocardiography was performed to assess cardiac function. Histological analysis was performed to assess MSCs retention, angiogenesis, and myocardial apoptosis. Additionally, the anti-apoptosis effects mediated by MSCs were further evaluated using flow cytometry in hypoxia H9C2 and HL-1 cells.

RESULTS

The RNA sequencing analysis revealed differences in gene expression related to angiogenesis and apoptosis pathways between UCMSCs and ADMSCs. UCMSCs presented greater pro-angiogenesis activity than ADMSCs in vitro and in vivo. Both of UCMSCs and ADMSCs improved cardiac function, decreased infarction area and inhibited cardiomyocyte apoptosis while promoting angiogenesis post-MI in mice. Notably, ADMSCs exerted a better cardioprotective function than UCMSCs and stronger anti-apoptotic effect on residual cardiomyocytes.

CONCLUSIONS

The protection of residual cells survival played a more prominent role than angiogenesis in MSCs-based therapy for acute MI. Our study provides new insights into therapeutic strategies and suggests that the optimal type of MSCs can be screened based on their tissue heterogeneity for precise clinical applications in acute MI.

Injectable Stem Cell-Based Therapies for Myocardial Regeneration: A Review of the Literature

Stem cell-based therapies are an emerging treatment modality aimed at replenishing lost cardiomyocytes and improving myocardial function after cardiac injury. This review examines the current state of research on injectable stem cell therapies in the setting of cardiovascular disease given their relative simplicity and ability for deep myocardial tissue penetration. Various methods of cell delivery, ranging in level of invasiveness and procedural complexity, have been developed, and numerous cell types have been studied as potential sources of stem cells, each with distinct advantages and disadvantages. We discuss key challenges associated with this approach, including low stem cell retention after transplantation and the innovative biomolecular strategies that have been explored to address this issue. Overall, investigations into the application of stem cells toward cardiac regeneration remain predominantly in the preclinical stage with a number of small, early-phase clinical trials. However, continued scientific advancements in stem cell technology may provide transformative treatment options for patients with heart failure, offering improved survival and quality of life.

Clinical translation of mesenchymal stem cells in ischemic heart failure: Challenges and future perspectives

Myocardial infarction (MI) with resulting congestive heart failure is one of the leading causes of death worldwide. Current therapies for treating MI, such as devices, traditional medicine, and surgeries, come with many limitations as patients in their final stages of heart failure have little chances of experiencing any reversible changes. In recent decades, Mesenchymal stem cell (MSC) based therapy has become one of the most popular and rapidly developing fields in treating MI. Their supremacy for clinical applications is partially due to their unique properties and encouraging pre-clinical outcomes in various animal disease models. However, the majority of clinical trials registered for MSC therapy for diverse human diseases, including MI, have fallen short of expectations. This review intends to discuss the recent advances in the clinical application of using MSCs for cardiac repair and discuss challenges facing the clinical translation of MSCs for cardiac regeneration such as restoration of endothelial-cardiomyocyte crosstalk, immunomodulation and immune rejection, poor homing and migration, as well as low retention and survival. Furthermore, we will discuss recent strategies being investigated to help overcome some of these challenges.

Human iPSC-derived mesenchymal stem cells relieve high blood pressure in spontaneously hypertensive rats via splenic nerve activated choline acetyltransferase-positive cells

Despite substantial advancements in modern medicine, the management of hypertension remains a major challenge. Stem cell-based therapies have recently demonstrated remarkable efficacy in treating cardiovascular diseases, including hypertension. However, the antihypertensive mechanism of mesenchymal stem cells (MSCs) has not been extensively explored. This study aimed to investigate the role of injected MSCs in regulating blood pressure homeostasis. Our previous study demonstrated that human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs) are functional and homogeneous sources for MSC-based therapy. After the injection of hiPSC-MSCs, a significant reduction in blood pressure and end target organ inflammation were observed in spontaneously hypertensive rats (SHRs). Cell tracking assays demonstrated that the injected hiPSC-MSCs accumulated in the spleens of the SHRs. The injected hiPSC-MSCs accumulated adjacent to the splenic nerve, potentially contributing to the antihypertensive effects. Furthermore, the hiPSC-MSCs released abundant glutamate, which acts as a neuromodulator to activate the splenic sympathetic nerve. After inhibition of glutamate synthesis by siRNA, the ability of hiPSC-MSCs to activate sympathetic nerves was significantly diminished. In addition, the antihypertensive effects of hiPSC-MSCs were eliminated after splenic nerve denervation (SND), underscoring the critical role of the splenic nerve. Moreover, activation of the splenic nerve resulted in increased release of norepinephrine (NE), which increased the number of choline acetyltransferase-positive (ChAT+) cells in the spleen and peripheral blood. Consequently, the acetylcholine (ACh) produced by elevated ChAT+ cells could act as a vasodilator, lowering blood pressure and mitigating inflammation in end target organs. In summary, our findings indicate that hiPSC-MSCs effectively lower blood pressure in hypertension by influencing the splenic nerves and regulating ChAT+ cells. The connection between blood pressure regulation and the splenic nerve may offer new insights into the treatment of hypertension.

Umbilical cord-derived mesenchymal stromal cells: Promising therapy for heart failure

Heart failure (HF) is a complex syndrome characterized by the reduced capacity of the heart to adequately fill or eject blood. Currently, HF remains a leading cause of morbidity and mortality worldwide, imposing a substantial burden on global healthcare systems. Recent advancements have highlighted the therapeutic potential of mesenchymal stromal cells (MSCs) in managing HF. Notably, umbilical cord-derived MSCs (UC-MSCs) have demonstrated superior clinical potential compared to traditional bone marrow-derived MSCs; this is evident in their non-invasive collection process, higher proliferation efficacy, and lower immunogenicity and tumorigenicity, as substantiated by preclinical studies. Although the feasibility and safety of UC-MSCs have been tested in animal models, the application of UC-MSCs in HF treatment remains challenged by issues such as inaccurate targeted migration and low survival rates of UC-MSCs. Therefore, further research and clinical trials are imperative to advance the clinical application of UC-MSCs.

Human umbilical cord mesenchymal stem cells promoted tumor cell growth associated with increased interleukin-18 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is experiencing a concerning rise in both incidence and mortality rates. Current therapeutic strategies are limited in their effectiveness, largely due to the complex causes of the disease and significant levels of drug resistance. Given the latest developments in human umbilical cord mesenchymal stem cells (hUC-MSCs) research, there is a debate over the continued use of stem cell transplantation for treating tumors. Consequently, this study seeks to explore the role of hUC-MSCs in the management of HCC.

METHODS AND RESULTS

HUC-MSCs increased the number (10.75 ± 1.50) in the DEN/TCPOBOP-induced mice hepatoma model, compared with DMSO group (7.25 ± 1.71). Moreover, the liver index in hUC-MSCs group (0.21 ± 0.06) was greater than that in DMSO group (0.09 ± 0.01). Immunohistochemical (IHC) analysis revealed that while hUC-MSCs did not alter Foxp3 expression, they significantly stimulated Ki67 expression, indicative of increased tumor cellular proliferation. Additionally, immunofluorescence (IF) studies showed that hUC-MSCs increased CD8+ T cell counts without affecting macrophage numbers. Notably, granzyme B expression remained nearly undetectable. We observed that serum IL-18 levels were higher in the hUC-MSCs group (109.66 ± 0.38 pg/ml) compared to the DMSO group (91.14 ± 4.37 pg/ml). Conversely, IL-1β levels decreased in the hUC-MSCs group (63.00 ± 0.53 pg/ml) relative to the DMSO group (97.38 ± 9.08 pg/ml).

CONCLUSIONS

According to this study, hUC-MSCs promoted the growth of liver tumors. Therefore, we proposed that hUC-MSCs are not suitable for treating HCC, as they exhibit clinically prohibited abnormalities.

The pig as an optimal animal model for cardiovascular research

Cardiovascular disease is a worldwide health problem and a leading cause of morbidity and mortality. Preclinical cardiovascular research using animals is needed to explore potential targets and therapeutic options. Compared with rodents, pigs have many advantages, with their anatomy, physiology, metabolism and immune system being more similar to humans. Here we present an overview of the available pig models for cardiovascular diseases, discuss their advantages over other models and propose the concept of standardized models to improve translation to the clinical setting and control research costs.

A division-of-labor mode contributes to the cardioprotective potential of mesenchymal stem/stromal cells in heart failure post myocardial infarction

Background

Treatment of heart failure post myocardial infarction (post-MI HF) with mesenchymal stem/stromal cells (MSCs) holds great promise. Nevertheless, 2-dimensional (2D) GMP-grade MSCs from different labs and donor sources have different therapeutic efficacy and still in a low yield. Therefore, it is crucial to increase the production and find novel ways to assess the therapeutic efficacy of MSCs.

Materials and methods

hUC-MSCs were cultured in 3-dimensional (3D) expansion system for obtaining enough cells for clinical use, named as 3D MSCs. A post-MI HF mouse model was employed to conduct in vivo and in vitro experiments. Single-cell and bulk RNA-seq analyses were performed on 3D MSCs. A total of 125 combination algorithms were leveraged to screen for core ligand genes. Shinyapp and shinycell workflows were used for deploying web-server.

Result

3D GMP-grade MSCs can significantly and stably reduce the extent of post-MI HF. To understand the stable potential cardioprotective mechanism, scRNA-seq revealed the heterogeneity and division-of-labor mode of 3D MSCs at the cellular level. Specifically, scissor phenotypic analysis identified a reported wound-healing CD142+ MSCs subpopulation that is also associated with cardiac protection ability and CD142- MSCs that is in proliferative state, contributing to the cardioprotective function and self-renewal, respectively. Differential expression analysis was conducted on CD142+ MSCs and CD142- MSCs and the differentially expressed ligand-related model was achieved by employing 125 combination algorithms. The present study developed a machine learning predictive model based on 13 ligands. Further analysis using CellChat demonstrated that CD142+ MSCs have a stronger secretion capacity compared to CD142- MSCs and Flow cytometry sorting of the CD142+ MSCs and qRT-PCR validation confirmed the significant upregulation of these 13 ligand factors in CD142+ MSCs.

Conclusion

Clinical GMP-grade 3D MSCs could serve as a stable cardioprotective cell product. Using scissor analysis on scRNA-seq data, we have clarified the potential functional and proliferative subpopulation, which cooperatively contributed to self-renewal and functional maintenance for 3D MSCs, named as "division of labor" mode of MSCs. Moreover, a ligand model was robustly developed for predicting the secretory efficacy of MSCs. A user-friendly web-server and a predictive model were constructed and available (https://wangxc.shinyapps.io/3D_MSCs/).

Stem cell-based therapy in cardiac repair after myocardial infarction: Promise, challenges, and future directions

Stem cells represent an attractive resource for cardiac regeneration. However, the survival and function of transplanted stem cells is poor and remains a major challenge for the development of effective therapies. As two main cell types currently under investigation in heart repair, mesenchymal stromal cells (MSCs) indirectly support endogenous regenerative capacities after transplantation, while induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) functionally integrate into the damaged myocardium and directly contribute to the restoration of its pump function. These two cell types are exposed to a common microenvironment with many stressors in ischemic heart tissue. This review summarizes the research progress on the mechanisms and challenges of MSCs and iPSC-CMs in post-MI heart repair, introduces several randomized clinical trials with 3D-mapping-guided cell therapy, and outlines recent findings related to the factors that affect the survival and function of stem cells. We also discuss the future directions for optimization such as biomaterial utilization, cell combinations, and intravenous injection of engineered nucleus-free MSCs.

Transplantation of Donor-Recipient Chimeric Cells Restores Peripheral Blood Cell Populations and Increases Survival after Total Body Irradiation-Induced Injury in a Rat Experimental Model

Current therapies for acute radiation syndrome (ARS) involve bone marrow transplantation (BMT), leading to graft-versus-host disease (GvHD). To address this challenge, we have developed a novel donor-recipient chimeric cell (DRCC) therapy to increase survival and prevent GvHD following total body irradiation (TBI)-induced hematopoietic injury without the need for immunosuppression. In this study, 20 Lewis rats were exposed to 7 Gy TBI to induce ARS, and we assessed the efficacy of various cellular therapies following systemic intraosseous administration. Twenty Lewis rats were randomly divided into four experimental groups (n = 5/group): saline control, allogeneic bone marrow transplantation (alloBMT), DRCC, and alloBMT + DRCC. DRCC were created by polyethylene glycol-mediated fusion of bone marrow cells from 24 ACI (RT1a) and 24 Lewis (RT11) rat donors. Fusion feasibility was confirmed by flow cytometry and confocal microscopy. The impact of different therapies on post-irradiation peripheral blood cell recovery was evaluated through complete blood count, while GvHD signs were monitored clinically and histopathologically. The chimeric state of DRCC was confirmed. Post-alloBMT mortality was 60%, whereas DRCC and alloBMT + DRCC therapies achieved 100% survival. DRCC therapy also led to the highest white blood cell counts and minimal GvHD changes in kidney and skin samples, in contrast to alloBMT treatment. In this study, transplantation of DRCC promoted the recovery of peripheral blood cell populations after TBI without the development of GVHD. This study introduces a novel and promising DRCC-based bridging therapy for treating ARS and extending survival without GvHD.

Canine amniotic membrane-derived mesenchymal stem cells ameliorate atopic dermatitis through regeneration and immunomodulation

Mesenchymal stem cells (MSCs) are a promising tool for treating immune disorders. However, the immunomodulatory effects of canine MSCs compared with other commercialized biologics for treating immune disorders have not been well studied. In this study we investigated the characteristics and immunomodulatory effects of canine amnion membrane (cAM)-MSCs. We examined gene expression of immune modulation and T lymphocytes from activated canine peripheral blood mononuclear cell (PBMC) proliferation. As a result, we confirmed that cAM-MSCs upregulated immune modulation genes (TGF-β1, IDO1 and PTGES2) and suppressed the proliferation capacity of T cells. Moreover, we confirmed the therapeutic effect of cAM-MSCs compared with oclacitinib (OCL), the most commonly used Janus kinase (JAK) inhibitor, as a treatment for canine atopic dermatitis (AD) using a mouse AD model. As a result, we confirmed that cAM-MSCs with PBS treatment groups (passage 4, 6 and 8) compared with PBS only (PBS) though scores of dermatologic signs, tissue pathologic changes and inflammatory cytokines were significantly reduced. In particular, cAM-MSCs were more effective than OCL in the recovery of wound dysfunction, regulation of mast cell activity and expression level of immune modulation protein. Interestingly, subcutaneous injection of cAM-MSCs induced weight recovery, but oral administration of oclacitinib induced weight loss as a side effect. In conclusion, this study suggests that cAM-MSCs can be developed as a safe canine treatment for atopic dermatitis without side effects through effective regeneration and immunomodulation.

The Safety and Efficacy of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Patients With Heart Failure and Myocardial Infarction: A Meta-Analysis of Clinical Trials

Evidence from preclinical and clinical studies suggests that human umbilical cord-derived mesenchymal stromal cells (HUC-MSCs) may be useful in treating heart failure and acute myocardial infarction (MI). However, the effects of stem cell therapy on patients with heart failure remain the subject of ongoing controversy, and the safety and effectiveness of HUC-MSCs therapy have not yet been proven. To date, there has been no systematic overview and meta-analysis of clinical studies using HUC-MSCs therapy for heart failure and MI. The purpose of this study is to assess the safety and efficacy of HUC-MSC therapy versus a placebo in patients with heart failure and MI. While preparing this systematic review and meta-analysis, we adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A computer literature search of PubMed was performed. We considered randomized controlled trials (RCTs) that reported data on the safety and efficacy of HUC-MSC transplantation in patients with heart failure and MI. Two investigators independently searched the literature, extracted data, and rated the quality of the included research. Pooled data were analyzed using the fixed-effect model or the random-effect model in Review Manager 5.3. The Cochrane risk of bias tool was used to assess the bias of included studies. The primary outcome was ejection fraction (EF), whereas the secondary outcomes were readmission and mortality rates. Three RCTs (201 patients) were included in this meta-analysis. The overall effect did not favor either of the two groups in terms of risk of readmission (risk ratio = 0.5, 95% confidence interval (CI) = 0.22-1.15, p = 0.10) as well as mortality rate (risk ratio = 0.44, 95% CI = 0.14-1.44, p = 0.18). However, there was an improvement in EF in patients who received HUC-MSCs compared to placebo after 12 months of transplantation (mean difference (MD) = 3.21, 95% CI = 2.91-3.51, p < 0.00001). At the six-month follow-up period, there was no significant improvement in EF (MD = 1.30, 95% CI = -1.94-4.54), p = 0.43), indicating that the duration of follow-up can shape the response to therapy. Our findings indicate that HUC-MSC transplantation can improve EF but has no meaningful effect on readmission or mortality rates. Existing evidence is insufficient to confirm the efficacy of HUC-MSCs for broader therapeutic applications. Therefore, additional double-blind RCTs with larger sample sizes are required.

Optimization of the cotransfection of SERCA2a and Cx43 genes for myocardial infarction complications

As our previous study showed, the therapeutic effect of two genes (SERCA2a and Cx43) on heart failure after myocardial infarction (MI) was greater than that of single gene (SERCA2a or Cx43) therapy for bone marrow stem cell (BMSC) transplantation. Based on previous research, the aim of this study was to investigate the optimal ratio of codelivery of SERCA2a and Cx43 genes for MI therapy after biotinylated microbubble (BMB) transplantation via ultrasonic-targeted microbubble destruction (UTMD). Forty rats underwent left anterior descending (LAD) ligation and BMSC injection into the infarct and border zones. Four weeks later, the genes SERCA2a and Cx43 were codelivered at different ratios (1:1, 1:2 and 2:1) into the infarcted heart via UTMD. Cardiac mechanoelectrical function was determined at 4 wks after gene delivery, and the hearts of the rats were harvested for measurement of MI size and detection of SERCA2a and Cx43 expression. Q-PCR analysis of the expression of Nkx2.5 and GATA4 in the myocardial infarct zone and measurement of neovascularization in infarcted hearts. After comparing the therapeutic effects of different cogene ratios, the SERCA2a/Cx43-1:2 group showed remarkable cardiac electrical stability and strengthened the role of anti-arrhythmia. In conclusion, the optimum ratio of the SERCA2a/Cx43 gene is 1:2, which is advantageous for maintaining cardiac electrophysiological stability.

Novel Human Umbilical Di-Chimeric (HUDC) cell therapy for transplantation without life-long immunosuppression

Background

Cell-based therapies are promising for tolerance induction in bone marrow (BM), solid organs, and vascularized composite allotransplantation (VCA). The toxicity of bone marrow transplantation (BMT) protocols precludes this approach from routine clinical applications. To address this problem, we developed a new therapy of Human Umbilical Di-Chimeric (HUDC) cells for tolerance induction in transplantation. This study established in vitro characterization of the created HUDC cells.

Methods

We performed sixteen ex vivo polyethylene glycol (PEG)-mediated fusions of human umbilical cord blood (UCB) cells from two unrelated donors. Fusion feasibility was confirmed in vitro by flow cytometry (FC) and confocal microscopy (CM). The HUDC cells' genotype was assessed by lymphocytotoxicity test and short tandem repeat-polymerase chain reaction (STR-PCR) analysis, phenotype by FC, viability by LIVE/DEAD® assay, and apoptosis level by Annexin V staining. We used COMET assay to assess HUDC cells' genotoxicity after the fusion procedure. Clonogenic properties of HUDC cells were evaluated by colony forming unit (CFU) assay. Mixed lymphocyte reaction (MLR) assay assessed immunogenic and tolerogenic properties of HUDC cells.

Results

We confirmed the creation of HUDC cells from two unrelated human donors of UCB cells by FC and CM. Human leukocyte antigen (HLA) class I and II typing, and STR-PCR analysis of HUDC cells confirmed the presence of alleles and loci from both unrelated UCB donors (donor chimerism: 49%±8.3%, n=4). FC confirmed the hematopoietic phenotype of HUDC cells. We confirmed high HUDC cells' viability (0.47% of dead cells) and a low apoptosis level of fused HUDC cells (15.9%) compared to positive control of PKH-stained UCB cells (20.4%) before fusion. COMET assay of HUDC cells revealed a lack of DNA damage. CFU assay confirmed clonogenic properties of HUDC cells, and MLR assay revealed a low immunogenicity of HUDC cells.

Conclusions

This study confirmed creation of a novel HUDC cell line by ex vivo PEG-mediated fusion of UCB cells from two unrelated donors. The unique concept of creating a HUDC cell line, representing the genotype and phenotype of both, transplant donor and the recipient, introduces a promising approach for tolerance induction in BM, solid organs, and VCA transplantation.

Spinal cord injury: molecular mechanisms and therapeutic interventions

Spinal cord injury (SCI) remains a severe condition with an extremely high disability rate. The challenges of SCI repair include its complex pathological mechanisms and the difficulties of neural regeneration in the central nervous system. In the past few decades, researchers have attempted to completely elucidate the pathological mechanism of SCI and identify effective strategies to promote axon regeneration and neural circuit remodeling, but the results have not been ideal. Recently, new pathological mechanisms of SCI, especially the interactions between immune and neural cell responses, have been revealed by single-cell sequencing and spatial transcriptome analysis. With the development of bioactive materials and stem cells, more attention has been focused on forming intermediate neural networks to promote neural regeneration and neural circuit reconstruction than on promoting axonal regeneration in the corticospinal tract. Furthermore, technologies to control physical parameters such as electricity, magnetism and ultrasound have been constantly innovated and applied in neural cell fate regulation. Among these advanced novel strategies and technologies, stem cell therapy, biomaterial transplantation, and electromagnetic stimulation have entered into the stage of clinical trials, and some of them have already been applied in clinical treatment. In this review, we outline the overall epidemiology and pathophysiology of SCI, expound on the latest research progress related to neural regeneration and circuit reconstruction in detail, and propose future directions for SCI repair and clinical applications.

Human-umbilical cord matrix mesenchymal cells improved left ventricular contractility independently of infarct size in swine myocardial infarction with reperfusion

Background

Human umbilical cord matrix-mesenchymal stromal cells (hUCM-MSC) have demonstrated beneficial effects in experimental acute myocardial infarction (AMI). Reperfusion injury hampers myocardial recovery in a clinical setting and its management is an unmet need. We investigated the efficacy of intracoronary (IC) delivery of xenogeneic hUCM-MSC as reperfusion-adjuvant therapy in a translational model of AMI in swine.

Methods

In a placebo-controlled trial, pot-belied pigs were randomly assigned to a sham-control group (vehicle-injection; n = 8), AMI + vehicle (n = 12) or AMI + IC-injection (n = 11) of 5 × 10⁵ hUCM-MSC/Kg, within 30 min of reperfusion. AMI was created percutaneously by balloon occlusion of the mid-LAD. Left-ventricular function was blindly evaluated at 8-weeks by invasive pressure-volume loop analysis (primary endpoint). Mechanistic readouts included histology, strength-length relationship in skinned cardiomyocytes and gene expression analysis by RNA-sequencing.

Results

As compared to vehicle, hUCM-MSC enhanced systolic function as shown by higher ejection fraction (65 ± 6% vs. 43 ± 4%; p = 0.0048), cardiac index (4.1 ± 0.4 vs. 3.1 ± 0.2 L/min/m²; p = 0.0378), preload recruitable stroke work (75 ± 13 vs. 36 ± 4 mmHg; p = 0.0256) and end-systolic elastance (2.8 ± 0.7 vs. 2.1 ± 0.4 mmHg*m²/ml; p = 0.0663). Infarct size was non-significantly lower in cell-treated animals (13.7 ± 2.2% vs. 15.9 ± 2.7%; Δ = -2.2%; p = 0.23), as was interstitial fibrosis and cardiomyocyte hypertrophy in the remote myocardium. Sarcomere active tension improved, and genes related to extracellular matrix remodelling (including MMP9, TIMP1 and PAI1), collagen fibril organization and glycosaminoglycan biosynthesis were downregulated in animals treated with hUCM-MSC.

Conclusion

Intracoronary transfer of xenogeneic hUCM-MSC shortly after reperfusion improved left-ventricular systolic function, which could not be explained by the observed extent of infarct size reduction alone. Combined contributions of favourable modification of myocardial interstitial fibrosis, matrix remodelling and enhanced cardiomyocyte contractility in the remote myocardium may provide mechanistic insight for the biological effect.

Large animal models for cardiac remuscularization studies: A methodological review

Myocardial infarction is the most common cause of heart failure, one of the most fatal non-communicable diseases worldwide. The disease could potentially be treated if the dead, ischemic heart tissues are regenerated and replaced with viable and functional cardiomyocytes. Pluripotent stem cells have proven the ability to derive specific and functional cardiomyocytes in large quantities for therapy. To test the remuscularization hypothesis, the strategy to model the disease in animals must resemble the pathophysiological conditions of myocardial infarction as in humans, to enable thorough testing of the safety and efficacy of the cardiomyocyte therapy before embarking on human trials. Rigorous experiments and in vivo findings using large mammals are increasingly important to simulate clinical reality and increase translatability into clinical practice. Hence, this review focus on large animal models which have been used in cardiac remuscularization studies using cardiomyocytes derived from human pluripotent stem cells. The commonly used methodologies in developing the myocardial infarction model, the choice of animal species, the pre-operative antiarrhythmics prophylaxis, the choice of perioperative sedative, anaesthesia and analgesia, the immunosuppressive strategies in allowing xenotransplantation, the source of cells, number and delivery method are discussed.

Inhibition of A1 Astrocytes and Activation of A2 Astrocytes for the Treatment of Spinal Cord Injury

Spinal cord injury (SCI) is a serious injury to the central nervous system that causes significant physical and psychological trauma to the patient. SCI includes primary spinal cord injuries and secondary spinal cord injuries. The secondary injury refers to the pathological process or reaction after the primary injury. Although SCI has always been thought to be an incurable injury, the human nerve has the ability to repair itself after an injury. However, the reparability is limited because glial scar formation impedes functional recovery. There is a type of astrocyte that can differentiate into two forms of reactive astrocytes known as 'A1' and 'A2' astrocytes. A1 astrocytes release cytotoxic chemicals that cause neurons and oligodendrocytes to die and perform a harmful role. A2 astrocytes can produce neurotrophic factors and act as neuroprotectors. This article discusses ways to block A1 astrocytes while stimulating A2 astrocytes to formulate a new treatment for spinal cord injury.

Mesenchymal stem cell-based therapy as a new therapeutic approach for acute inflammation

Acute inflammatory diseases such as acute colitis, kidney injury, liver failure, lung injury, myocardial infarction, pancreatitis, septic shock, and spinal cord injury are significant causes of death worldwide. Despite advances in the understanding of its pathophysiology, there are many restrictions in the treatment of these diseases, and new therapeutic approaches are required. Mesenchymal stem cell-based therapy due to immunomodulatory and regenerative properties is a promising candidate for acute inflammatory disease management. Based on preclinical results, mesenchymal stem cells and their-derived secretome improved immunological and clinical parameters. Furthermore, many clinical trials of acute kidney, liver, lung, myocardial, and spinal cord injury have yielded promising results. In this review, we try to provide a comprehensive view of mesenchymal stem cell-based therapy in acute inflammatory diseases as a new treatment approach.

Greater angiogenic and immunoregulatory potency of bFGF and 5-aza-2'-deoxycytidine pre-treated menstrual blood stem cells in compare to bone marrow stem cells in rat model of myocardial infarction

BACKGROUND

This study is designed to compare the menstrual blood stem cells (MenSCs) and bone marrow stem cells (BMSCs)-secreted factors with or without pre-treatment regimen using basic fibroblast growth factor (bFGF) and 5-aza-2'-deoxycytidine (5-aza) and also regenerative capacity of pre-treated MenSCs and/or BMSCs in a rat model of myocardial infarction (MI).

METHODS

BMSCs and MenSCs were pre-treated with bFGF and 5-aza for 48 h and we compared the paracrine activity by western blotting. Furthermore, MI model was created and the animals were divided into sham, MI, pre-treated BMSCs, and pre-treated MenSCs groups. The stem cells were administrated via tail vain. 35 days post-MI, serum and tissue were harvested for further investigations.

RESULTS

Following pre-treatment, vascular endothelium growth factor, hypoxia-inducible factor-1, stromal cell-derived factor-1, and hepatocyte growth factor were significantly increased in secretome of MenSCs in compared to BMSCs. Moreover, systemic administration of pre-treated MenSCs, leaded to improvement of cardiac function, preservation of myocardium from further subsequent injuries, promotion the angiogenesis, and reduction the level of NF-κB expression in compared to the pre-treated BMSCs. Also, pre-treated MenSCs administration significantly decreased the serum level of Interleukin 1 beta (IL-1β) in compared to the pre-treated BMSCs and MI groups.

CONCLUSIONS

bFGF and 5-aza pre-treated MenSCs offer superior cardioprotection compare to bFGF and 5-aza pre-treated BMSCs following MI.

Single-photon emission computed tomography as a fundamental tool in evaluation of myocardial reparation and regeneration therapies

Despite unquestionable progress in interventional and pharmacologic therapies of ischemic heart disease, the number of patients with chronic ischemic heart failure is increasing and the prognosis remains poor. Repair/restoration of functional myocardium through progenitor cell-mediated (PCs) healing and renovation of injured myocardium is one of the pivotal directions in biomedical research. PCs release numerous pro-angiogenic and anti-apoptotic factors. Moreover, they have self-renewal capability and may differentiate into specialized cells that include endothelial cells and cardiomyocytes. Uptake and homing of PCs in the zone(s) of ischaemic injury (i.e., their effective transplantation to the target zone) is an essential pre-requisite for any potential therapeutic effect; thus effective cell tracking is fundamental in pre-clinical and early clinical studies. Another crucial requirement in rigorous research is quantification of the infarct zone, including the amount of non-perfused and hypo-perfused myocardium. Quantitative and reproducible evaluation of global and regional myocardial contractility and left ventricular remodeling is particularly relevant in clinical studies. Using SPECT, our earlier work has addressed several critical questions in cardiac regenerative medicine including optimizing transcoronary cell delivery, determination of the zone(s) of myocardial cell uptake, and late functional improvement in relation to the magnitude of cell uptake. Here, we review the role of single-photon emission computed tomography (SPECT), a technique that offers high-sensitivity, quantitative cell tracking on top of its ability to evaluate myocardial perfusion and function on both cross-sectional and longitudinal bases. SPECT, with its direct relevance to routine clinical practice, is a fundamental tool in evaluation of myocardial reparation and regeneration therapies.

Umbilical cord mesenchymal stromal cells-from bench to bedside

In recent years, mesenchymal stromal cells (MSCs) have generated a lot of attention due to their paracrine and immuno-modulatory properties. mesenchymal stromal cells derived from the umbilical cord (UC) are becoming increasingly recognized as having increased therapeutic potential when compared to mesenchymal stromal cells from other sources. The purpose of this review is to provide an overview of the various compartments of umbilical cord tissue from which mesenchymal stromal cells can be isolated, the differences and similarities with respect to their regenerative and immuno-modulatory properties, as well as the single cell transcriptomic profiles of in vitro expanded and freshly isolated umbilical cord-mesenchymal stromal cells. In addition, we discuss the therapeutic potential and biodistribution of umbilical cord-mesenchymal stromal cells following systemic administration while providing an overview of pre-clinical and clinical trials involving umbilical cord-mesenchymal stromal cells and their associated secretome and extracellular vesicles (EVs). The clinical applications of umbilical cord-mesenchymal stromal cells are also discussed, especially in relation to obstacles and potential solutions for their effective translation from bench to bedside.

Systematic comparation of the biological and transcriptomic landscapes of human amniotic mesenchymal stem cells under serum-containing and serum-free conditions

Background

Human amniotic mesenchymal stem cells (hAMSCs) are splendid cell sources for clinical application in the administration of numerous refractory and relapse diseases. Despite the preferable prospect of serum-free (SF) condition for cell product standardization and pathogenic contamination remission, yet the systematic and detailed impact upon hAMSCs at both cellular and transcriptomic levels is largely obscure.

Methods

For the purpose, we preconditioned hAMSCs under serum-containing (SC) and SF medium for 48 h and compared the biological signatures and biofunctions from the view of cell morphology, immunophenotypes, multi-lineage differentiation in vitro, cell vitality, cytokine expression, and immunosuppressive effect upon the subpopulations of T lymphocytes, together with the PI3K-AKT-mTOR signaling reactivation upon cell vitality. Meanwhile, we took advantage of RNA-SEQ and bioinformatic analyses to verify the gene expression profiling and genetic variation spectrum in the indicated hAMSCs.

Results

Compared with those maintained in SC medium, hAMSCs pretreated in SF conditions manifested conservation in cell morphology, immunophenotypes, adipogenic differentiation, and immunosuppressive effect upon the proliferation and activation of most of the T cell subpopulations, but with evaluated cytokine expression (e.g., TGF-β1, IDO1, NOS2) and declined osteogenic differentiation and cell proliferation as well as proapoptotic and apoptotic cells. The declined proliferation in the SF group was efficiently rescued by PI3K-AKT-mTOR signaling reactivation. Notably, hAMSCs cultured in SF and SC conditions revealed similarities in gene expression profiling and variations in genetic mutation at the transcriptome level. Instead, based on the differentially expressed genes and variable shear event analyses, we found those genes were mainly involved in DNA synthesis-, protein metabolism-, and cell vitality-associated biological processes and signaling pathways (e.g., P53, KRAS, PI3K-Akt-mTOR).

Conclusions

Collectively, our data revealed the multifaceted cellular and molecular properties of hAMSCs under SC and SF conditions, which suggested the feasibility of serum-free culture for the preferable preparation of standardized cell products for hAMSC drug development and clinical application.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03179-2.

Overexpression of PYGO1 promotes early cardiac lineage development in human umbilical cord mesenchymal stromal/stem cells by activating the Wnt/β-catenin pathway

Cardiovascular disease still has the highest mortality. Gene-modified mesenchymal stromal/stem cells could be a promising therapy. Pygo plays an important role in embryonic development and regulates life activities with a variety of regulatory mechanisms. Therefore, this study aimed to investigate whether the overexpression of the PYGO1 gene can promote the differentiation of human umbilical cord-derived mesenchymal stromal/stem cells (HUC-MSCs) into early cardiac lineage cells and to preliminary explore the relevant mechanisms. In this study, HUC-MSCs were isolated by the explant method and were identified by flow cytometry and differentiation assay, followed by transfected with lentivirus carrying the PYGO1 plasmid. In PYGO1 group (cells were incubated with lentiviral-PYGO1), the mRNA expressions of cardiac differentiation-specific markers (MESP1, NKX2.5, GATA4, MEF2C, ISL1, TBX5, TNNT2, ACTC1, and MYH6 genes) and the protein expressions of NKX2.5 and cTnT were significantly up-regulated compared with the NC group (cells were incubated with lentiviral-empty vector). In addition, the proportion of NKX2.5, GATA4, and cTnT immunofluorescence-positive cells increased with the inducement time. Overexpression of PYGO1 statistically significantly increased the relative luciferase expression level of Topflash plasmid, the protein expression level of β-catenin and the mRNA expression level of CYCLIND1. Compared with the control group, decreased protein levels of NKX2.5 and cTnT were detected in PYGO1 group after application of XAV-939, the specific inhibitor of the canonical Wnt/β-catenin pathway. Our study suggests that overexpression of PYGO1 significantly promotes the differentiation of HUC-MSCs into early cardiac lineage cells, which is regulated by the canonical Wnt/β-catenin signaling.

Intramyocardial injected human umbilical cord-derived mesenchymal stem cells (HucMSCs) contribute to the recovery of cardiac function and the migration of CD4+ T cells into the infarcted heart via CCL5/CCR5 signaling

BACKGROUND

Human umbilical cord-derived mesenchymal stem cells (HucMSCs) have been recognized as a promising cell for treating myocardial infarction (MI). Inflammatory response post MI is critical in determining the cardiac function and subsequent adverse left ventricular remodeling. However, the local inflammatory effect of HucMSCs after intramyocardial injection in murine remains unclear.

METHODS

HucMSCs were cultured and transplanted into the mice after MI surgery. Cardiac function of mice were analyzed among MI-N.S, MI-HucMSC and MI-HucMSC-C-C Motif Chemokine receptor 5 (CCR5) antagonist groups, and angiogenesis, fibrosis and hypertrophy, and immune cells infiltration of murine hearts were evaluated between MI-N.S and MI-HucMSC groups. We detected the expression of inflammatory cytokines and their effects on CD4+ T cells migration.

RESULTS

HucMSCs treatment can significantly improve the cardiac function and some cells can survive at least 28 days after MI. Intramyocardial administration of HucMSCs also improved angiogenesis and alleviated cardiac fibrosis and hypertrophy. Moreover, we found the much higher numbers of CD4+ T cells and CD4+FoxP3+ regulatory T cells (Tregs) in the heart with HucMSCs than that with N.S treatment on day 7 post MI. In addition, the protein level of C-C Motif Chemokine Ligand 5 (CCL5) greatly increased in HucMSCs treated heart compared to MI-N.S group. In vitro, HucMSCs inhibited CD4+ T cells migration and addition of CCL5 antibody or CCR5 antagonist significantly reversed this effect. In vivo results further showed that addition of CCR5 antagonist can reduce the cardioprotective effect of HucMSCs administration on day 7 post MI injury.

CONCLUSION

These findings indicated that HucMSCs contributed to cardiac functional recovery and attenuated cardiac remodeling post MI. Intramyocardial injection of HucMSCs upregulated the CD4+FoxP3+ Tregs and contributed to the migration of CD4+ T cells into the injured heart via CCL5/CCR5 pathway.

Referred Somatic Hyperalgesia Mediates Cardiac Regulation by the Activation of Sympathetic Nerves in a Rat Model of Myocardial Ischemia

Myocardial ischemia (MI) causes somatic referred pain and sympathetic hyperactivity, and the role of sensory inputs from referred areas in cardiac function and sympathetic hyperactivity remain unclear. Here, in a rat model, we showed that MI not only led to referred mechanical hypersensitivity on the forelimbs and upper back, but also elicited sympathetic sprouting in the skin of the referred area and C8-T6 dorsal root ganglia, and increased cardiac sympathetic tone, indicating sympathetic-sensory coupling. Moreover, intensifying referred hyperalgesic inputs with noxious mechanical, thermal, and electro-stimulation (ES) of the forearm augmented sympathetic hyperactivity and regulated cardiac function, whereas deafferentation of the left brachial plexus diminished sympathoexcitation. Intradermal injection of the α₂ adrenoceptor (α₂AR) antagonist yohimbine and agonist dexmedetomidine in the forearm attenuated the cardiac adjustment by ES. Overall, these findings suggest that sensory inputs from the referred pain area contribute to cardiac functional adjustment via peripheral α₂AR-mediated sympathetic-sensory coupling.

Optimal Delivery Route of Mesenchymal Stem Cells for Cardiac Repair: The Path to Good Clinical Practice

Research has shown that mesenchymal stem cells (MSCs) could be a promising therapy for treating progressive heart disease. However, translation into clinics efficiently and successfully has proven to be much more complicated. Many questions remain for optimizing treatment. Application method influences destiny of MSCs and afterwards impacts results of procedure, yet there is no general agreement about most suitable method of MSC delivery in the clinical setting. Herein, we explain principle of most-frequent MSCs delivery techniques in cardiology. This chapter summarizes crucial translational obstacles of clinical employment of MSCs for cardiac repair when analysed trough a prism of latest research centred on different techniques of MSCs application.

Effect of intravenous cell therapy in rats with old myocardial infarction

Mounting evidence shows that cell therapy provides therapeutic benefits in experimental and clinical settings of chronic heart failure. However, direct cardiac delivery of cells via transendocardial injection is logistically complex, expensive, entails risks, and is not amenable to multiple dosing. Intravenous administration would be a more convenient and clinically applicable route for cell therapy. Thus, we determined whether intravenous infusion of three widely used cell types improves left ventricular (LV) function and structure and compared their efficacy. Rats with a 30-day-old myocardial infarction (MI) received intravenous infusion of vehicle (PBS) or 1 of 3 types of cells: bone marrow mesenchymal stromal cells (MSCs), cardiac mesenchymal cells (CMCs), and c-kit-positive cardiac cells (CPCs), at a dose of 12 × 106 cells. Rats were followed for 35 days after treatment to determine LV functional status by serial echocardiography and hemodynamic studies. Blood samples were collected for Hemavet analysis to determine inflammatory cell profile. LV ejection fraction (EF) dropped ≥ 20 points in all hearts at 30 days after MI and deteriorated further at 35-day follow-up in the vehicle-treated group. In contrast, deterioration of EF was halted in rats that received MSCs and attenuated in those that received CMCs or CPCs. None of the 3 types of cells significantly altered scar size, myocardial content of collagen or CD45-positive cells, or Hemavet profile. This study demonstrates that a single intravenous administration of 3 types of cells in rats with chronic ischemic cardiomyopathy is effective in attenuating the progressive deterioration in LV function. The extent of LV functional improvement was greatest with CPCs, intermediate with CMCs, and least with MSCs.

The effects of mesenchymal stem cells transplantation on A1 neurotoxic reactive astrocyte and demyelination in the cuprizone model

Multiple sclerosis (MS), which is an autoimmune disease, is characterized by symptoms such as demyelination, axonal damage, and astrogliosis. As the most abundant type of glial cells, astrocytes play an important role in MS pathogenesis. Mesenchymal stem cells (MSCs) are a subset of stromal cells that have the potential for migration, immune-modulation, differentiation, remyelination, and neuroregeneration. Therefore, the present study evaluates the effects of MSC transplantation on A1 reactive astrocytes and the remyelination process in the cuprizone mouse model. The study used 30 male C57BL/6 mice, which were randomly distributed into three subgroups (n = 10), i.e., control, cuprizone, and transplanted MSCs groups. In order to generate a chronic demyelination model, the mice in the cuprizone group received food mixed with 0.2% cuprizone powder for 12 weeks. Then, 2 μl of DMEM containing approximately 3 × 10⁵ DiI labeled cells was injected with a 4-min interval into the right lateral ventricle using a 10-μl Hamilton syringe. After 2 weeks of cell transplantation, we used the rotarod test to evaluate the behavioral deficits, while the remyelination process was assessed by transmission electron microscopy (TEM) and Luxol Fast Blue (LFB) staining. We assessed the population of A1 astrocytes and oligodendrocytes using specific markers, such as C3, GFAP, and Olig2, using the immunefleurocent method. The pro-inflammatory and trophic factors were assessed by a real-time polymerase chain reaction. According to our data, the specific marker of A1 astrocytes (C3) decreased in the MSCs group, while the number of oligodendrocytes significantly increased in this group compared to the cuprizone mice. Additionally, MSC was able to enhance the remyelination process after cuprizone usage, as shown by LFB and TEM images. The molecular results showed that MSCs could reduce pro-inflammatory factors, such as IL-1 and TNF-α, through the secretion of BDNF and TGF-β as trophic factors. The obtained results indicated that MSC could reduce demyelination and inflammation by decreasing A1 neurotoxic reactive astrocytes and neurotrophic and immunomodulatory factors secretion in the chronic cuprizone demyelination model.

MSC Pretreatment for Improved Transplantation Viability Results in Improved Ventricular Function in Infarcted Hearts

Many clinical studies utilizing MSCs (mesenchymal stem cells, mesenchymal stromal cells, or multipotential stromal cells) are underway in multiple clinical settings; however, the ideal approach to prepare these cells in vitro and to deliver them to injury sites in vivo with maximal effectiveness remains a challenge. Here, pretreating MSCs with agents that block the apoptotic pathways were compared with untreated MSCs. The treatment effects were evaluated in the myocardial infarct setting following direct injection, and physiological parameters were examined at 4 weeks post-infarct in a rat permanent ligation model. The prosurvival treated MSCs were detected in the hearts in greater abundance at 1 week and 4 weeks than the untreated MSCs. The untreated MSCs improved ejection fraction in infarcted hearts from 61% to 77% and the prosurvival treated MSCs further improved ejection fraction to 83% of normal. The untreated MSCs improved fractional shortening in the infarcted heart from 52% to 68%, and the prosurvival treated MSCs further improved fractional shortening to 77% of normal. Further improvements in survival of the MSC dose seems possible. Thus, pretreating MSCs for improved in vivo survival has implications for MSC-based cardiac therapies and in other indications where improved cell survival may improve effectiveness.

Constructing a cell microenvironment with biomaterial scaffolds for stem cell therapy

Stem cell therapy is widely recognized as a promising strategy for exerting therapeutic effects after injury in degenerative diseases. However, limitations such as low cell retention and survival rates after transplantation exist in clinical applications. In recent years, emerging biomaterials that provide a supportable cellular microenvironment for transplanted cells have optimized the therapeutic efficacy of stem cells in injured tissues or organs. Advances in the engineered microenvironment are revolutionizing our understanding of stem cell-based therapies by co-transplanting with synthetic and tissue-derived biomaterials, which offer a scaffold for stem cells and propose an unprecedented opportunity to further employ significant influences in tissue repair and regeneration.

Umbilical cord mesenchymal stem/stromal cells potential to treat organ disorders; an emerging strategy

Currently, mesenchymal stem/stromal cells (MSCs) have attracted growing attention in the context of cell-based therapy in regenerative medicine. Following the first successful procurement of human MSCs from bone marrow (BM), these cells isolation has been conducted from various origins, in particular, the umbilical cord (UC). Umbilical cord-derived mesenchymal stem/stromal cells (UC-MSCs) can be acquired by a non-invasive plan and simply cultured, and thereby signifies their superiority over MSCs derived from other sources for medical purposes. Due to their unique attributes, including self-renewal, multipotency, and accessibility concomitant with their immunosuppressive competence and lower ethical concerns, UC-MSCs therapy is described as encouraging therapeutic options in cell-based therapies. Regardless of their unique aptitude to adjust inflammatory response during tissue recovery and delivering solid milieu for tissue restoration, UC-MSCs can be differentiated into a diverse spectrum of adult cells (e.g., osteoblast, chondrocyte, type II alveolar, hepatocyte, and cardiomyocyte). Interestingly, they demonstrate a prolonged survival and longer telomeres compared with MSCs derived from other sources, suggesting that UC-MSCs are desired source to use in regenerative medicine. In the present review, we deliver a brief review of UC-MSCs isolation, expansion concomitantly with immunosuppressive activities, and try to collect and discuss recent pre-clinical and clinical researches based on the use of UC-MSCs in regenerative medicine, focusing on with special focus on in vivo researches.

Therapeutic prospects of mesenchymal stem/stromal cells in COVID-19 associated pulmonary diseases: From bench to bedside

The ongoing outbreak of coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 has become a sudden public emergency of international concern and seriously threatens millions of people’s life health. Two current studies have indicated a favorable role for mesenchymal stem/stromal cells (MSCs) in clinical remission of COVID-19 associated pulmonary diseases, yet the systematical elaboration of the therapeutics and underlying mechanism is far from satisfaction. In the present review, we summarize the therapeutic potential of MSCs in COVID-19 associated pulmonary diseases such as pneumonia induced acute lung injury, acute respiratory distress syndrome, and pulmonary fibrosis. Furthermore, we review the underlying mechanism of MSCs including direct- and trans-differentiation, autocrine and paracrine anti-inflammatory effects, homing, and neovascularization, as well as constitutive microenvironment. Finally, we discuss the prospects and supervision of MSC-based cytotherapy for COVID-19 management before large-scale application in clinical practice. Collectively, this review supplies overwhelming new references for understanding the landscapes of MSCs in the remission of COVID-19 associated pulmonary diseases.

Comparing the Therapeutic Potential of Stem Cells and their Secretory Products in Regenerative Medicine

Cell therapy involves the transplantation of human cells to replace or repair the damaged tissues and modulate the mechanisms underlying disease initiation and progression in the body. Nowadays, many different types of cell-based therapy are developed and used to treat a variety of diseases. In the past decade, cell-free therapy has emerged as a novel approach in regenerative medicine after the discovery that the transplanted cells exerted their therapeutic effect mainly through the secretion of paracrine factors. More and more evidence showed that stem cell-derived secretome, i.e., growth factors, cytokines, and extracellular vesicles, can repair the injured tissues as effectively as the cells. This finding has spurred a new idea to employ secretome in regenerative medicine. Despite that, will cell-free therapy slowly replace cell therapy in the future? Or are these two modes of treatment still needed to address different diseases and conditions? This review provides an indepth discussion about the values of stem cells and secretome in regenerative medicine. In addition, the safety, efficacy, advantages, and disadvantages of using these two modes of treatment in regenerative medicine are also critically reviewed.

Human umbilical cord tissue-derived mesenchymal stromal cells as adjuvant therapy for myocardial infarction: a review of current evidence focusing on pre-clinical large animal models and early human trials

Although biologically appealing, the concept of tissue regeneration underlying first- and second-generation cell therapies has failed to translate into consistent results in clinical trials. Several types of cells from different origins have been tested in pre-clinical models and in patients with acute myocardial infarction (AMI). Mesenchymal stromal cells (MSCs) have gained attention because of their potential for immune modulation and ability to promote endogenous tissue repair, mainly through their secretome. MSCs can be easily obtained from several human tissues, the umbilical cord being the most abundant source, and further expanded in culture, making them attractive as an allogeneic "of-the-shelf" cell product, suitable for the AMI setting. The available evidence concerning umbilical cord-derived MSCs in AMI is reviewed, focusing on large animal pre-clinical studies and early human trials. Molecular and cellular mechanisms as well as current limitations and possible translational solutions are also discussed.

MiR-467a-5p aggravates myocardial infarction by modulating ZEB1 expression in mice

Myocardial infarction (MI) is a great threat to patients all over the word. MicroRNAs (miRNAs) are a group of non-coding RNAs and can regulate initiation and progression of MI. The current research aimed to investigate the role of miR-467a-5p in MI. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was conducted to detective relative expression of miR-467a-5p in cardiac tissues and mouse cardiomyocytes (MCMs). Hematoxylin and eosin staining was used to reveal the histology of the myocardium. Echocardiography was utilized to reveal cardiac function of mice. Flow cytometer analysis was used to reveal cell apoptosis. Luciferase reporter assay was applied for determining the binding capacity between molecules. We discovered that the level of miR-467a-5p was up-regulated in MI mice and in MCMs induced by H₂O₂ or hypoxia. Functionally, an elevation of left ventricular end-diastolic diameter and left ventricular end-systolic diameter, as well as a decrease of left ventricular ejection fraction and left ventricular fractional shortening were observed in MI mice. In addition, deficiency of miR-467a-5p improved MI in mice by increasing the contents of lactate dehydrogenase, creatine kinase and malondialdehyde and reducing the activity of superoxide dismutase in serum. Moreover, silencing of miR-467a-5p reversed hypoxia-induced apoptosis of MCMs. Mechanistically, zinc finger E-box binding homeobox 1 (ZEB1) was confirmed as the target of miR-467a-5p. Moreover, miR-467a-5p negatively regulated ZEB1 level in MI mice and MCMs. Finally, the promotive effect of miR-467a-5p inhibition on cell apoptosis was reversed by knockdown of ZEB1. All the experimental results demonstrate that miR-467a-5p aggravates MI by modulating ZEB1 expression in mice, which may provide a novel therapeutic strategy for MI.

Current Status and Limitations of Myocardial Infarction Large Animal Models in Cardiovascular Translational Research

Establishing an appropriate disease model that mimics the complexities of human cardiovascular disease is critical for evaluating the clinical efficacy and translation success. The multifaceted and complex nature of human ischemic heart disease is difficult to recapitulate in animal models. This difficulty is often compounded by the methodological biases introduced in animal studies. Considerable variations across animal species, modifications made in surgical procedures, and inadequate randomization, sample size calculation, blinding, and heterogeneity of animal models used often produce preclinical cardiovascular research that looks promising but is irreproducible and not translatable. Moreover, many published papers are not transparent enough for other investigators to verify the feasibility of the studies and the therapeutics' efficacy. Unfortunately, successful translation of these innovative therapies in such a closed and biased research is difficult. This review discusses some challenges in current preclinical myocardial infarction research, focusing on the following three major inhibitors for its successful translation: Inappropriate disease model, frequent modifications to surgical procedures, and insufficient reporting transparency.

Cell Therapy in Patients with Heart Failure: A Comprehensive Review and Emerging Concepts

This review summarizes the results of clinical trials of cell therapy in patients with heart failure (HF). In contrast to acute myocardial infarction (where results have been consistently negative for more than a decade), in the setting of HF the results of Phase I–II trials are encouraging, both in ischaemic and non-ischaemic cardiomyopathy. Several well-designed Phase II studies have met their primary endpoint and demonstrated an efficacy signal, which is remarkable considering that only one dose of cells was used. That an efficacy signal was seen 6–12 months after a single treatment provides a rationale for larger, rigorous trials. Importantly, no safety concerns have emerged. Amongst the various cell types tested, mesenchymal stromal cells derived from bone marrow (BM), umbilical cord, or adipose tissue show the greatest promise. In contrast, embryonic stem cells are not likely to become a clinical therapy. Unfractionated BM cells and cardiosphere-derived cells have been abandoned. The cell products used for HF will most likely be allogeneic. New approaches, such as repeated cell treatment and intravenous delivery, may revolutionize the field. As is the case for most new therapies, the development of cell therapies for HF has been slow, plagued by multifarious problems, and punctuated by many setbacks; at present, the utility of cell therapy in HF remains to be determined. What the field needs is rigorous, well-designed Phase III trials. The most important things to move forward are to keep an open mind, avoid preconceived notions, and let ourselves be guided by the evidence.

Placenta-Expanded Stromal Cell Therapy in a Rodent Model of Simulated Weightlessness

Long duration spaceflight poses potential health risks to astronauts during flight and re-adaptation after return to Earth. There is an emerging need for NASA to provide successful and reliable therapeutics for long duration missions when capability for medical intervention will be limited. Clinically relevant, human placenta-derived therapeutic stromal cells (PLX-PAD) are a promising therapeutic alternative. We found that treatment of adult female mice with PLX-PAD near the onset of simulated weightlessness by hindlimb unloading (HU, 30 d) was well-tolerated and partially mitigated decrements caused by HU. Specifically, PLX-PAD treatment rescued HU-induced thymic atrophy, and mitigated HU-induced changes in percentages of circulating neutrophils, but did not rescue changes in the percentages of lymphocytes, monocytes, natural killer (NK) cells, T-cells and splenic atrophy. Further, PLX-PAD partially mitigated HU effects on the expression of select cytokines in the hippocampus. In contrast, PLX-PAD failed to protect bone and muscle from HU-induced effects, suggesting that the mechanisms which regulate the structure of these mechanosensitive tissues in response to disuse are discrete from those that regulate the immune- and central nervous system (CNS). These findings support the therapeutic potential of placenta-derived stromal cells for select physiological deficits during simulated spaceflight. Multiple countermeasures are likely needed for comprehensive protection from the deleterious effects of prolonged spaceflight.

Specific protein 1 inhibitor mithramycin A protects cardiomyocytes from myocardial infarction via interacting with PARP

Specific protein 1 (SP1) might act as a critical transcription regulator in myocardial infarction (MI), but little evidence about its function in regulating cardiac apoptosis, a major cause of MI development, has been revealed. This study tried to investigate the role of SP1 in MI and its interaction with poly-ADP-ribose polymerase (PARP)-1 by using SP1 inhibitor, mithramycin A (mithA). Primary mouse cardiomyocytes and commercial mouse cardiomyocytes were subjected to mithA treatment under hypoxia conditions, while cell viability, Nix promoter activity, and its expression were detected correspondingly. PARP overexpression and knockdown were conducted, respectively, in mithA-treated and SP1-overexpressing cells. Co-immunoprecipitation was used to verify the interaction between PARP and SP1. For in vivo experiments, mithA administration was performed after the injections of adenovirus for PARP overexpression, and then, MI introduction was carried out. Infarct size and lactate dehydrogenase level were measured to assess MI injury. SP1 inhibitor mithA attenuated hypoxia-induced decrease of cell viability and Nix transcriptional activation, which could be inhibited by PARP overexpression. Knockdown of PARP prevented SP1-induced transcription of Nix and cell viability change, and PARP showed direct interaction with SP1. Furthermore, mithA administration reduced MI injuries, while PARP overexpression could suppress the improvement. The cardioprotective role of SP1 inhibitor mithA was demonstrated here expanding the role of SP1 in MI development involving hypoxia-induced cardiac apoptosis. Moreover, PARP acted as a transcriptional coactivator in Nix transcription involving its interaction with SP1.

Multifaceted Optimization of MSC-Based Formulation upon Sodium Iodoacetate-Induced Osteoarthritis Models by Combining Advantageous HA/PG Hydrogel and Fluorescent Tracer

Owing to the boundedness of conventional remedies upon articular cartilage for self-rehabilitation and the incrementally senior citizens, the incidence of osteoarthritis (OA) is increasing worldwide. Empirical studies have revealed the advantageous and promising potentials of mesenchymal stem/stromal cells (MSCs) on the refractory OA, whereas the deficiency of systematic and detailed exploration of MSC-based therapy largely hampers the large-scale applications in regenerative medicine. Herein, we initially utilized the monosodium iodoacetate- (MIA-) induced OA rabbit models and investigated the therapeutic effect of human umbilical cord-derived UC-MSCs at serial dose gradients with the splendid hyaluronic acid and/or propylene glycol hydrogels (HA, HA/PG), respectively. Afterwards, we turned to a dual-luciferase reporter tracing system and evaluated the spatiotemporal distribution and metabolokinetics of bifluorescence expressing UC-MSCs (BF-MSCs) in OA rats. Of the aforementioned trials, we verified that the combination of HA/PG and middle-dose MSCs ( $0.5\times {10}^7$ cells/ml) eventually manifested the optimal efficacy on OA rabbits. Furthermore, with the aid of the bioluminescence imaging (BLI) technology for dynamic in vitro and in vivo tracking, we intuitively delineated the spatiotemporal distribution and therapeutic process of BF-MSCs in OA rats, which substantially confirmed the reinforcement of HA/PG on BF-MSCs for OA treatment. Collectively, our data conformably demonstrated that the middle dose of UC-MSCs combined with HA/PG hydrogel was sufficient for optimal MSC-based formulation for blocking OA progression and promoting cartilage repair, which supplied overwhelming new references and enlightened MSC-based therapeutic strategies for cartilage defects.

Two-step generation of mesenchymal stem/stromal cells from human pluripotent stem cells with reinforced efficacy upon osteoarthritis rabbits by HA hydrogel

Background

Current studies have enlightened the rosy prospects of human pluripotent stem cell (hPSC)-derived mesenchymal stem/stromal cells (MSCs) in regenerative medicine. However, systematic investigation of their signatures and applications with alternative biomaterials in osteoarthritis (OA) remains indistinct.

Methods

Herein, we initially took advantage of a small molecule library-mediated programming strategy for hPSC-MSC induction. Then, with the aid of multifaceted analyses such as flow cytometry (FCM), chromosome karyocyte and cell vitality, wound healing and microtubule formation assay and coculturing with T lymphocytes, we systematically evaluated the characterizations of signatures in vitro and the in vivo efficacy of hPSC-MSCs and HA hydrogel composite on rabbit osteoarthritis model.

Results

We found the combination of LLY-507 and AZD5153 was sufficient for high-efficiency CD73⁺CD90⁺CD105⁺CD31⁻CD34⁻CD45⁻HLA-DR⁻ MSC induction from both hESCs and hiPSCs with stemness (POU5F1/SOX2/NANOG). The programmed hPSC-MSCs revealed conservative transcriptome variations and went through a heterogeneous intermediate-stage with mesenchymal-associated gene expression (NT5E, ENG, VIM and FN1) as well as displayed typical cytomorphology, immunophenotypes and normal karyotyping, multilineage differentiation potential, favorable cell vitality, proangiogenic and immunoregulatory properties in vitro. Meanwhile, the cell population exhibited preferable restorative and ameliorative function on OA rabbits with HA hydrogel in vivo.

Conclusions

Collectively, we established a rapid and convenient procedure for hPSC-MSC generation without redundant manipulations. The fundamental and clinical studies upon osteoarthritis (OA) treatment would benefit tremendously from the combination of the inexhaustible hPSC-MSCs and advantageous biomaterials.

Progress and Challenges of Amniotic Fluid Derived Stem Cells in Therapy of Ischemic Heart Disease

Cardiovascular disease is the leading cause of deaths worldwide, claiming an estimated total of 17.9 million lives each year, of which one-third of the people are under the age of 70 years. Since adult cardiomyocytes fail to regenerate, the heart loses the ability to repair itself after an injury, making patients with heart disease suffer from poor prognosis. Pluripotent stem cells have the ability to differentiate into cardiomyocytes in vitro through a well-established process, which is a new advancement in cardiac regeneration therapy. However, pluripotent stem cell-derived cardiomyocytes have certain drawbacks, such as the risk of arrhythmia and immune incompatibility. Thus, amniotic fluid stem cells (AFSCs), a relatively novel source of stem cells, have been exploited for their ability of pluripotent differentiation. In addition, since AFSCs are weakly positive for the major histocompatibility class II molecules, they may have high immune tolerance. In summary, the possibility of development of cardiomyocytes from AFSCs, as well as their transplantation in host cells to produce mechanical contraction, has been discussed. Thus, this review article highlights the progress of AFSC therapy and its application in the treatment of heart diseases in recent years.

What is the impact of human umbilical cord mesenchymal stem cell transplantation on clinical treatment?

Background

Human umbilical cord mesenchymal stem cells (HUC-MSCs) present in the umbilical cord tissue are self-renewing and multipotent. They can renew themselves continuously and, under certain conditions, differentiate into one or more cell types constituting human tissues and organs. HUC-MSCs differentiate, among others, into osteoblasts, chondrocytes, and adipocytes and have the ability to secrete cytokines. The possibility of noninvasive harvesting and low immunogenicity of HUC-MSCs give them a unique advantage in clinical applications. In recent years, HUC-MSCs have been widely used in clinical practice, and some progress has been made in their use for therapeutic purposes.

Main body

This article describes two aspects of the clinical therapeutic effects of HUC-MSCs. On the one hand, it explains the benefits and mechanisms of HUC-MSC treatment in various diseases. On the other hand, it summarizes the results of basic research on HUC-MSCs related to clinical applications. The first part of this review highlights several functions of HUC-MSCs that are critical for their therapeutic properties: differentiation into terminal cells, immune regulation, paracrine effects, anti-inflammatory effects, anti-fibrotic effects, and regulating non-coding RNA. These characteristics of HUC-MSCs are discussed in the context of diabetes and its complications, liver disease, systemic lupus erythematosus, arthritis, brain injury and cerebrovascular diseases, heart diseases, spinal cord injury, respiratory diseases, viral infections, and other diseases. The second part emphasizes the need to establish an HUC-MSC cell bank, discusses tumorigenicity of HUC-MSCs and the characteristics of different in vitro generations of these cells in the treatment of diseases, and provides technical and theoretical support for the clinical applications of HUC-MSCs.

Conclusion

HUC-MSCs can treat a variety of diseases clinically and have achieved good therapeutic effects, and the development of HUC-MSC assistive technology has laid the foundation for its clinical application.

Spatio-Temporal Metabolokinetics and Efficacy of Human Placenta-Derived Mesenchymal Stem/Stromal Cells on Mice with Refractory Crohn's-like Enterocutaneous Fistula

Crohn's disease (CD) with externally fistulizing openings indicates the aggressive and relapsing manifestation and results in undesirable long-term outcomes of patients. MSC-based approach combined with multidisciplinary strategy has mandated a redefinition of the administration and management of numerous recurrent and refractory diseases whereas the spatio-temporal evaluation of the metabolokinetics and efficacy of MSCs on intractable CD with enterocutaneous fistula (EF) are largely inaccessible and dauntingly complex. Herein, we primitively established dual-fluorescence expressing placenta-derived MSCs (DF-MSCs) and explored their multidimensional attributes, including cytomorphology, immunophenotying, multilineage differentiation and long-term proliferation, together with the recognition of bifluorescence intensity (BLI). Then, with the aid of in vivo living imaging, clinicopathological or inflammatory cytokine examinations and in vitro analyses, we systematically and meticulously dissected the metabolokinetics and curative effect of MSCs on mice with refractory Crohn's-like EF (EF mice), together with revealing the underlying mechanism including reactive oxygen species (ROS) and neovascularization. Strikingly, the DF-MSCs exhibited stabilized BLI and biological properties. The spatio-temporal distribution and therapeutic process of MSCs in EF mice were intuitively delineated. Meanwhile, our data indicated the curative mechanisms of DF-MSCs by simultaneously downregulating ROS and accelerating neovascularization. Collectively, we systematically illuminated the spatio-temporal biofunction and mechanism of DF-MSCs on EF mice. Our findings have supplied new references for safety and effectiveness assessments as well as the establishment of guidelines for optimal administrations of MSC-based cytotherapy in preclinical studies, which collectively indicates the prospect of P-MSC administration in clinical trials during a wide spectrum of disease remodeling including the fistulizing CD. Graphical abstract.

Advances in translational orthopaedic research with species-specific multipotent mesenchymal stromal cells derived from the umbilical cord

Compliance with current regulations for the development of innovative medicines require the testing of candidate therapies in relevant translational animal models prior to human use. This poses a great challenge when the drug is composed of cells, not only because of the living nature of the active ingredient but also due to its human origin, which can subsequently lead to a xenogeneic response in the animals. Although immunosuppression is a plausible solution, this is not suitable for large animals and may also influence the results of the study by altering mechanisms of action that are, in fact, poorly understood. For this reason, a number of procedures have been developed to isolate homologous species-specific cell types to address preclinical pharmacodynamics, pharmacokinetics and toxicology. In this work, we present and discuss advances in the methodologies for derivation of multipotent Mesenchymal Stromal Cells derived from the umbilical cord, in general, and Wharton's jelly, in particular, from medium to large animals of interest in orthopaedics research, as well as current and potential applications in studies addressing proof of concept and preclinical regulatory aspects.

Accuracy of cardiac functional parameters measured from gated radionuclide myocardial perfusion imaging in mice

BACKGROUND

Quantitative cardiac contractile function assessment is the primary indicator of disease progression and therapeutic efficacy in small animals. Operator dependency is a major challenge with commonly used echocardiography. Simultaneous assessment of cardiac perfusion and function in nuclear scans would reduce burden on the animal and facilitate longitudinal studies. We evaluated the accuracy of contractile function measurements obtained from electrocardiogram-gated nuclear perfusion imaging compared with anatomic imaging.

METHODS AND RESULTS

In healthy C57Bl/6N mice (n = 11), 99mTc-sestamibi SPECT and 13N-ammonia PET underestimated left ventricular volumes (23 to 28%, P = 0.02) compared to matched anatomic images, though ejection fraction (LVEF) was comparable (%, SPECT: 73 ± 8 vs CMR: 72 ± 6, P = 0.1). At 1 week after myocardial infarction (n = 13), LV volumes were significantly lower in perfusion images compared to CMR and contrast CT (P = 0.003), and LVEF was modestly overestimated (%, SPECT: 37 ± 8, vs CMR: 27 ± 7, P = 0.003). Nuclear images exhibited good intra- and inter-reader agreement. Perfusion SPECT accurately calculated infarct size compared to histology (r = 0.95, P < 0.001).

CONCLUSIONS

Cardiac function can be calculated by gated nuclear perfusion imaging in healthy mice. After infarction, perfusion imaging overestimates LVEF, which should be considered for comparison to other modalities. Combined functional and infarct size analysis may optimize imaging protocols and reduce anaesthesia duration for longitudinal studies.

Adipose Tissue-Derived Stem Cells from Type 2 Diabetics Reveal Conservative Alterations in Multidimensional Characteristics

Background and Objectives

Adipose tissue-derived mesenchymal stem cells (ASCs) are recognized as an advantaged source for the prevention and treatment of diverse diseases including type 2 diabetes mellitus (T2DM). However, alterations in characteristics of ASCs from the aforementioned T2DM patients are still obscure, which also hinder the rigorous and systematic illumination of progression and pathogenesis.

Methods and Results

In this study, we originally isolated peripancreatic adipose tissue-derived mesenchymal stem cells from both human type 2 diabetic and non-diabetic donors (T2DM-ASCs, ND-ASCs) with the parental consent, respectively. We noticed that T2DM-ASCs exhibited indistinguishable immunophenotype, cell vitality, chondrogenic differentiation and stemness as ND-ASCs. Simultaneously, there’s merely alterations in migration and immunoregulatory capacities in T2DM-ASCs. However, differing from ND-ASCs, T2DM-ASCs exhibited deficiency in adipogenic and osteogenic differentiation, and in particular, the delayed cell cycle and different cytokine expression spectrum.

Conclusions

The conservative alterations of T2DM-ASCs in multifaceted characteristics indicated the possibility of autologous application of ASCs for cell-based T2DM treatment in the future.

Comparison of the effects of intramyocardial and intravenous injections of human mesenchymal stem cells on cardiac regeneration after heart failure

OBJECTIVES

Existing studies have demonstrated that intravenous and intramyocardial-administrated mesenchymal stem cells (MSCs) lead to tissue repair after cardiac disorders. We compared the efficiency of both administration methods.

MATERIALS AND METHODS

A rat model of isoproterenol-induced heart failure (ISO-HF) was established to compare the effects of intravenous and intramyocardial-administrated MSCs on cardiac fibrosis and function. The animals were randomly assigned into six groups: i) control or normal, ii) ISO-HF (HF) iii) ISO-HF rats treated with intramyocardial administration of culture medium (HF+IM/CM), iv) ISO-HF rats treated with intravenous administration of culture medium ( HF+IV/CM), v) ISO-HF rats treated with intravenous administration of MSCs (HF+IV/MSCs), vi) ISO-HF rats treated with intramyocardial administration of MSCs ( HF+IM/MSCs). Cultured MSCs and culture medium were administrated at 4 weeks after final injection of ISO. Heart function, identification of MSCs, osteogenic differentiation, adipogenic differentiation, cardiac fibrosis and tissue damage were evaluated by echocardiography, flow-cytometery, von Kossa, oil red O, Masson's trichrome and H & E staining, respectively.

RESULTS

Both intravenous and intramyocardial MSCs therapy significantly improved heart function and reduced cardiac fibrosis and tissue damage (P<0.05), whereas the cultured medium had no beneficial effects.

CONCLUSION

In sum, our results confirm the validity of both administration methods in recovery of HF, but more future research is required.