Allogeneic transplantation of fetal membrane-derived mesenchymal stem cell sheets increases neovascularization and improves cardiac function after myocardial infarction in rats. Transplantation. 2013;96:697-706. [PMID: 23912174 DOI: 10.1097/tp.0b013e31829f753d]

Effect of trehalose on heart functions in rats model after myocardial infarction: assessment of novel intraventricular pressure and heart rate variability

Background

Myocardial infarctions remain a leading cause of global deaths. Developing novel drugs to target cardiac remodeling after myocardial injury is challenging. There is an increasing interest in exploring natural cardioprotective agents and non-invasive tools like intraventricular pressure gradients (IVPG) and heart rate variability (HRV) analysis in myocardial infarctions. Trehalose (TRE), a natural disaccharide, shows promise in treating atherosclerosis, myocardial infarction, and neurodegenerative disorders.

Objectives

The objective of this study was to investigate the effectiveness of TRE in improving cardiac functions measured by IVPG and HRV and reducing myocardial remodeling following myocardial infarction in rat model.

Methods

Rats were divided into three groups: sham, myocardial infarction (MI), and trehalose-treated MI (TRE) groups. The animals in the MI and TRE groups underwent permanent ligation of the left anterior descending artery. The TRE group received 2% trehalose in their drinking water for four weeks after the surgery. At the end of the experiment, heart function was assessed using conventional echocardiography, novel color M-mode echocardiography for IVPG evaluation, and HRV analysis. After euthanasia, gross image scoring, histopathology, immunohistochemistry, and quantitative real-time PCR were performed to evaluate inflammatory reactions, oxidative stress, and apoptosis.

Results

The MI group exhibited significantly lower values in multiple IVPG parameters. In contrast, TRE administration showed an ameliorative effect on IVPG changes, with results comparable to the sham group. Additionally, TRE improved HRV parameters, mitigated morphological changes induced by myocardial infarction, reduced histological alterations in wall mass, and suppressed inflammatory reactions within the infarcted heart tissues. Furthermore, TRE demonstrated antioxidant, anti-apoptotic and anti-fibrotic properties.

Conclusion

The investigation into the effect of trehalose on a myocardial infarction rat model has yielded promising outcomes, as evidenced by improvements observed through conventional echocardiography, histological analysis, and immunohistochemical analysis. While minor trends were noticed in IVPG and HRV measurements. However, our findings offer valuable insights and demonstrate a correlation between IVPG, HRV, and other traditional markers of echo assessment in the myocardial infarction vs. sham groups. This alignment suggests the potential of IVPG and HRV as additional indicators for future research in this field.

Progress and promise of cell sheet assisted cardiac tissue engineering in regenerative medicine

Cardiovascular diseases (CVDs) are the most common leading causes of premature deaths in all countries. To control the harmful side effects of CVDs on public health, it is necessary to understand the current and prospective strategies in prevention, management, and monitoring CVDs.In vitro,recapitulating of cardiac complex structure with its various cell types is a challenging topic in tissue engineering. Cardiac tissue engineering (CTE) is a multi-disciplinary strategy that has been considered as a novel alternative approach for cardiac regenerative medicine and replacement therapies. In this review, we overview various cell types and approaches in cardiac regenerative medicine. Then, the applications of cell-sheet-assisted CTE in cardiac diseases were discussed. Finally, we described how this technology can improve cardiac regeneration and function in preclinical and clinical models.

Progress in Biomaterials for Cardiac Tissue Engineering and Regeneration

Cardiovascular diseases are one of the leading global causes of morbidity and mortality, posing considerable health and economic burden on patients and medical systems worldwide. This phenomenon is attributed to two main motives: poor regeneration capacity of adult cardiac tissues and insufficient therapeutic options. Thus, the context calls for upgrading treatments to deliver better outcomes. In this respect, recent research has approached the topic from an interdisciplinary perspective. Combining the advances encountered in chemistry, biology, material science, medicine, and nanotechnology, performant biomaterial-based structures have been created to carry different cells and bioactive molecules for repairing and restoring heart tissues. In this regard, this paper aims to present the advantages of biomaterial-based approaches for cardiac tissue engineering and regeneration, focusing on four main strategies: cardiac patches, injectable hydrogels, extracellular vesicles, and scaffolds and reviewing the most recent developments in these fields.

Cell-Based and Selected Cell-Free Therapies for Myocardial Infarction: How Do They Compare to the Current Treatment Options?

Because of cardiomyocyte death or dysfunction frequently caused by myocardial infarction (MI), heart failure is a leading cause of morbidity and mortality in modern society. Paradoxically, only limited and non-curative therapies for heart failure or MI are currently available. As a result, over the past two decades research has focused on developing cell-based approaches promoting the regeneration of infarcted tissue. Cell-based therapies for myocardial regeneration include powerful candidates, such as multipotent stem cells (mesenchymal stem cells (MSCs), bone-marrow-derived stem cells, endothelial progenitor cells, and hematopoietic stem cells) and induced pluripotent stem cells (iPSCs). These possess unique properties, such as potency to differentiate into desired cell types, proliferation capacity, and patient specificity. Preclinical and clinical studies have demonstrated modest improvement in the myocardial regeneration and reduced infarcted areas upon transplantation of pluripotent or multipotent stem cells. Another cell population that need to be considered as a potential source for cardiac regeneration are telocytes found in different organs, including the heart. Their therapeutic effect has been studied in various heart pathologies, such as MI, arrhythmias, or atrial amyloidosis. The most recent cell-free therapeutic tool relies on the cardioprotective effect of complex cargo carried by small membrane-bound vesicles—exosomes—released from stem cells via exocytosis. The MSC/iPSC-derived exosomes could be considered a novel exosome-based therapy for cardiovascular diseases thanks to their unique content. There are also other cell-free approaches, e.g., gene therapy, or acellular cardiac patches. Therefore, our review provides the most recent insights into the novel strategies for myocardial repair based on the regenerative potential of different cell types and cell-free approaches.

2,5-Dimethylcelecoxib attenuates cardiac fibrosis caused by cryoinjury-induced myocardial infarction by suppressing the fibroblast-to-myofibroblast transformation via inhibition of the TGF-β signaling pathway

We previously reported that 2,5-dimethylcelecoxib (DM-C), a derivative of celecoxib, lacks cyclooxygenase-2 inhibitory effects and suppresses cardiac remodeling by activating glycogen synthase kinase-3 (GSK-3). However, it remains unclear whether DM-C attenuates fibroblast-to-myofibroblast transformation (FMT), which plays a key role in cardiac fibrosis. Therefore, we evaluated the effect of DM-C on FMT using a cryoinjury-induced myocardial infarction (CMI) mouse model. We found that DM-C attenuated the deterioration of left ventricular ejection fraction after CMI by decreasing cardiac fibrosis. Analysis of the expression level of α-smooth muscle actin (α-SMA), a marker for myofibroblasts, indicated that DM-C decreased FMT at the cardiac injury site. To investigate the mechanism by which DM-C attenuated FMT, fibroblasts obtained from the heart were stimulated with TGF-β to induce FMT, and the effect of DM-C was analyzed. DM-C suppressed the expression of α-SMA and the phosphorylation levels of Smad 2/3 and GSK-3, indicating that DM-C suppressed α-SMA expression by inhibiting the transforming growth factor (TGF)-β signaling pathway via activation of GSK-3. DM-C decreased the expression of collagen, connective tissue growth factor (CTGF) and Snail, which are also known to accelerate cardiac fibrosis. These results suggested that DM-C attenuated cardiac fibrosis by suppressing FMT at the injured site after CMI by inhibiting the TGF-β signaling pathway via activation of GSK-3. Thus, DM-C has potential against cardiac disease as a novel anti-fibrotic agent.

Hopes and Hurdles of Employing Mesenchymal Stromal Cells in the Treatment of Cardiac Fibrosis

Excessive cardiac fibrosis plays a crucial role in almost all types of heart disease. Generally, cardiac fibrosis is a scarring process triggered in response to stress, injury, or aging and is characterized by the accumulation of activated myofibroblasts that deposit high levels of extracellular matrix proteins in the myocardium. While it is beneficial for cardiac repair in the short term, it can also result in pathological remodeling, tissue stiffening, and cardiac dysfunction, contributing to the progression of heart failure, arrhythmia, and sudden cardiac death. Despite its high prevalence, there is a lack of effective and safe therapies that specifically target myofibroblasts to inhibit or even reverse pathological cardiac fibrosis. In the past few decades, cell therapy has been under continuous evaluation as a potential treatment strategy, and several studies have shown that transplantation of mesenchymal stromal cells (MSCs) can reduce cardiac fibrosis and improve heart function. Mechanistically, it is believed that the heart benefits from MSC therapy by stimulating innate anti-fibrotic and regenerative reactions. The mechanisms of action include paracrine signaling and cell-to-cell interactions. In this review, we provide an overview of the anti-fibrotic properties of MSCs and approaches to enhance them and discuss future directions of MSCs for the treatment of cardiac fibrosis.

Mesenchymal Stem Cells Therapies on Fibrotic Heart Diseases

Stem cell therapy is a promising alternative approach to heart diseases. The most prevalent source of multipotent stem cells, usually called somatic or adult stem cells (mesenchymal stromal/stem cells, MSCs) used in clinical trials is bone marrow (BM-MSCs), adipose tissue (AT-MSCs), umbilical cord (UC-MSCs) and placenta. Therapeutic use of MSCs in cardiovascular diseases is based on the benefits in reducing cardiac fibrosis and inflammation that compose the cardiac remodeling responsible for the maintenance of normal function, something which may end up causing progressive and irreversible dysfunction. Many factors lead to cardiac fibrosis and failure, and an effective therapy is lacking to reverse or attenuate this condition. Different approaches have been shown to be promising in surpassing the poor survival of transplanted cells in cardiac tissue to provide cardioprotection and prevent cardiac remodeling. This review includes the description of pre-clinical and clinical investigation of the therapeutic potential of MSCs in improving ventricular dysfunction consequent to diverse cardiac diseases.

Engineered cell-degradable poly(2-alkyl-2-oxazoline) hydrogel for epicardial placement of mesenchymal stem cells for myocardial repair

Epicardial placement of mesenchymal stromal cells (MSCs) is a promising strategy for cardiac repair post-myocardial infarction, but requires the design of biomaterials to maximise the retention of donor cells on the heart surface and control their phenotype. To this end, we propose the use of a poly(2-alkyl-2-oxazoline) (POx) derivative, based on 2-ethyl-2-oxazoline and 2-butenyl-2-oxazoline. This POx polymer can be cured rapidly (less than 2 min) via photo-irradiation due to the use of di-cysteine cell degradable peptides. We report that the cell-degradable properties of the resulting POx hydrogels enables the regulation of cell protrusion in corresponding 3D matrices and that this, in turn, regulates the secretory phenotype of MSCs. In particular, the expression of pro-angiogenic genes was upregulated in partially cell-degradable POx hydrogels. Improved angiogenesis was confirmed in an in vitro microfluidic assay. Finally, we confirmed that, owing to the excellent tissue adhesive properties of thiol-ene crosslinked hydrogels, the epicardial placement of MSC-loaded POx hydrogels promoted the recovery of cardiac function and structure with reduced interstitial fibrosis and improved neovascular formation in a rat myocardial infarction model. This report demonstrates that engineered synthetic hydrogels displaying controlled mechanical, cell degradable and bioactive properties are particularly attractive candidates for the epicardial placement of stem cells to promote cardiac repair post myocardial infarction.

Molecular Crosstalk Between Macrophages and Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) have been widely investigated for regenerative medicine applications, from treating various inflammatory diseases as a cell therapy to generating engineered tissue constructs. Numerous studies have evaluated the potential effects of MSCs following therapeutic administration. By responding to their surrounding microenvironment, MSCs may mediate immunomodulatory effects through various mechanisms that directly (i.e., contact-dependent) or indirectly (i.e., paracrine activity) alter the physiology of endogenous cells in various disease pathologies. More specifically, a pivotal crosstalk between MSCs and tissue-resident macrophages and monocytes (TMφ) has been elucidated using in vitro and in vivo preclinical studies. An improved understanding of this crosstalk could help elucidate potential mechanisms of action (MOAs) of therapeutically administered MSCs. TMφ, by nature of their remarkable functional plasticity and prevalence within the body, are uniquely positioned as critical modulators of the immune system – not only in maintaining homeostasis but also during pathogenesis. This has prompted further exploration into the cellular and molecular alterations to TMφ mediated by MSCs. In vitro assays and in vivo preclinical trials have identified key interactions mediated by MSCs that polarize the responses of TMφ from a pro-inflammatory (i.e., classical activation) to a more anti-inflammatory/reparative (i.e., alternative activation) phenotype and function. In this review, we describe physiological and pathological TMφ functions in response to various stimuli and discuss the evidence that suggest specific mechanisms through which MSCs may modulate TMφ phenotypes and functions, including paracrine interactions (e.g., secretome and extracellular vesicles), nanotube-mediated intercellular exchange, bioenergetics, and engulfment by macrophages. Continued efforts to elucidate this pivotal crosstalk may offer an improved understanding of the immunomodulatory capacity of MSCs and inform the development and testing of potential MOAs to support the therapeutic use of MSCs and MSC-derived products in various diseases.

Differentiation-inducing factor-1 potentiates adipogenic differentiation and attenuates the osteogenic differentiation of bone marrow-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) are an attractive cell source for tissue regeneration and repair. However, their low differentiation efficacy currently impedes the development of MSC therapy. Therefore, in this study, we investigated the effects of differentiation-inducing factor-1 (DIF-1) on the differentiation efficacy of bone marrow-derived MSCs (BM-MSCs) into adipogenic or osteogenic lineages. BM-MSCs, which were obtained from Sprague-Dawley rats, were positive for the MSC markers (CD29, CD73, and CD90). DIF-1 alone neither affected cell surface antigen expression nor induced adipogenic or osteogenic differentiation. However, DIF-1 significantly enhanced the effects of adipogenic differentiation stimuli, which were evaluated as the number of oil red-O positive cells and the expression of adipocyte differentiation markers (peroxisome proliferator-activated receptor gamma, adipocyte fatty acid-binding protein, and adiponectin). In contrast, DIF-1 significantly attenuated the effects of osteogenic differentiation stimuli, which were evaluated as alizarin red-S positive calcium deposition, and the expression of osteoblast differentiation markers alkaline phosphatase, runt-related transcription factor 2, and osteopontin. We further investigated the mechanism by which DIF-1 affects MSC differentiation efficacy and found that glycogen synthase kinase-3 was the main factor mediating the action of DIF-1 on the adipogenic differentiation of BM-MSCs, whereas it was only partially involved in osteogenic differentiation. These results suggest that DIF-1 supports MSC differentiation toward the desired cell fate by enhancing the differentiation efficacy.

Anti-fibrotic mechanisms of exogenously-expanded mesenchymal stromal cells for fibrotic diseases

Most chronic diseases involving inflammation have a fibrotic component that involves remodeling and excess accumulation of extracellular matrix components. Left unchecked, fibrosis leads to organ failure and death. Mesenchymal stromal cells (MSCs) are emerging as a potent cell-based therapy for a wide spectrum of fibrotic conditions due to their immunomodulatory, anti-inflammatory and anti-fibrotic properties. This review provides an overview of known mechanisms by which MSCs mediate their anti-fibrotic actions and in relation to animal models of pulmonary, liver, renal and cardiac fibrosis. Recent MSC clinical trials results in liver, lung, skin, kidney and hearts are discussed and next steps for future MSC-based therapies including pre-activated or genetically-modified cells, or extracellular vesicles are also considered.

A clinical-grade acellular matrix for esophageal replacement

In pathologies of the esophagus such as esophageal atresia, cancers, and caustic injuries, methods for full thickness esophageal replacement require the sacrifice of healthy intra-abdominal organs such as the stomach and the colon and are associated with high morbidity, mortality, and poor functional results. To overcome these problems, tissue engineering methods are developed to create a substitute with scaffolds and cells. The aim of this study was to develop a simple and safe decellularization process in order to obtain a clinical grade esophageal extracellular matrix. Following the decontamination step, porcine esophagi were decellularized in a bioreactor with sodium dodecyl sulfate and ethylenediaminetetraacetic acid for 3 days and were rinsed with deionized water. DNA was eliminated by a 3-hr DNase treatment. To remove any residual detergent, the matrix was then incubated with an absorbing resin. The resulting porcine esophageal matrix was characterized by the assessment of the efficiency of the decellularization process (DNA quantification), evaluation of sterility and absence of cytotoxicity, and its composition and biomechanical properties, as well as the possibility to be reseeded with mesenchymal stem cells. Complete decellularization with the preservation of the general structure, composition, and biomechanical properties of the native esophageal matrix was obtained. Sterility was maintained throughout the process, and the matrix showed no cytotoxicity. The resulting matrix met clinical grade criteria and was successfully reseeded with mesenchymal stem cells..

Stem Cell Therapy for Tendon Regeneration: Current Status and Future Directions

In adults the healing tendon generates fibrovascular scar tissue and recovers never histologically, mechanically, and functionally which leads to chronic and to degenerative diseases. In this review, the processes and mechanisms of tendon development and fetal regeneration in comparison to adult defect repair and degeneration are discussed in relation to regenerative therapeutic options. We focused on the application of stem cells, growth factors, transcription factors, and gene therapy in tendon injury therapies in order to intervene the scarring process and to induce functional regeneration of the lesioned tissue. Outlines for future therapeutic approaches for tendon injuries will be provided.

Safety and efficacy of amnion-derived mesenchymal stem cells (AM01) in patients with steroid-refractory acute graft-versus-host disease after allogeneic haematopoietic stem cell transplantation: a study protocol for a phase I/II Japanese trial

INTRODUCTION

Regenerative medicine and cell therapies have been gaining much attention among clinicians. Therapeutic infusion of mesenchymal stromal cells (MSCs) is now a leading investigational strategy for the treatment of acute graft-versus-host disease (aGVHD). Bone marrow MSCs are approved for manufacture and marketing as a cell therapy for aGVHD. Our non-clinical studies confirmed that human amnion-derived MSCs had immunomodulatory activity equal to or higher than that of human bone marrow MSCs. This study will aim to evaluate the safety and efficacy of amnion-derived MSCs (AM01) in patients with steroid-refractory aGVHD.

METHODS AND ANALYSIS

This study will be a multicentre, single-arm, open-label trial (an interventional study). This clinical trial will begin with a low-dose group, and when safety has been confirmed in at least three cases in the low-dose group, treatment will begin for the high-dose group, for which the safety will also be verified. The primary endpoint is to assess the safety of intravenous infusion therapy of AM01 within 24 hours after intravenous infusion of AM01. The secondary endpoint is to explore the efficacy of intravenous infusion therapy with AM01.

ETHICS AND DISSEMINATION

The institutional review boards of all participating hospitals approved this study protocol (latest V3.3.0, 3 August 2018). Final data will be publicly announced. A report releasing the study results will be submitted for publication to an appropriate peer-reviewed journal.

TRIAL REGISTRATION NUMBER

UMIN000029945.

[Analysis of Biological Properties of Human Adult Mesenchymal Stem Cells and Their Effect on Mouse Hind Limb Ischemia]

BACKGROUND

Due to their self-renewal, proliferation, differentiation, and angiogenesis-inducing capacity, human adipose mesenchymal stem cells (AMSC) have potential clinical applications in the treatment of limb ischemia. AMSC from healthy donors have been shown to induce neovascularization in animal models. However, when cells were obtained from donors suffering from any pathology, their autologous application showed limited effectiveness. We studied whether liposuction niche and obesity could determine the regenerative properties of cells meaning that not all cell batches are suitable for clinical practice.

METHODS

AMSC obtained from 10 donors, obese and healthy, were expanded in vitro following a good manufacturing practice-like production protocol. Cell viability, proliferation kinetics, morphological analysis, phenotype characterization, and stemness potency were assessed over the course of the expansion process. AMSC selected for having the most suitable biological properties were used as an experimental treatment in a preclinical mouse model of hind limb ischemia.

RESULT

All cell batches were positively characterized as mesenchymal stem cells, but not all of them showed the same properties or were successfully expanded in vitro, depending on the characteristics of the donor and the extraction area. Notably, AMSC from the abdomen of obese donors showed undesirable biological properties. AMSC with low duplication times and multilineage differentiation potential and forming large densely packed colonies, were able, following expansion in vitro, to increase neovascularization and repair when implanted in the ischemic tissue of mice.

CONCLUSION

An extensive AMSC biological properties study could be useful to predict the potential clinical efficacy of cells before in vivo transplantation. Thus, peripheral ischemia and possibly other pathologies could benefit from stem cell treatments as shown in our preclinical model in terms of tissue damage repair and regeneration after ischemic injury.

Mesenchymal Stromal Cell Homing: Mechanisms and Strategies for Improvement

Mesenchymal stromal cells (MSCs) have been widely investigated for their therapeutic potential in regenerative medicine, owing to their ability to home damaged tissue and serve as a reservoir of growth factors and regenerative molecules. As such, clinical applications of MSCs are reliant on these cells successfully migrating to the desired tissue following their administration. Unfortunately, MSC homing is inefficient, with only a small percentage of cells reaching the target tissue following systemic administration. This attrition represents a major bottleneck in realizing the full therapeutic potential of MSC-based therapies. Accordingly, a variety of strategies have been employed in the hope of improving this process. Here, we review the molecular mechanisms underlying MSC homing, based on a multistep model involving (1) initial tethering by selectins, (2) activation by cytokines, (3) arrest by integrins, (4) diapedesis or transmigration using matrix remodelers, and (5) extravascular migration toward chemokine gradients. We then review the various strategies that have been investigated for improving MSC homing, including genetic modification, cell surface engineering, in vitro priming of MSCs, and in particular, ultrasound techniques, which have recently gained significant interest. Contextualizing these strategies within the multistep homing model emphasizes that our ability to optimize this process hinges on our understanding of its molecular mechanisms. Moving forward, it is only with a combined effort of basic biology and translational work that the potential of MSC-based therapies can be realized.

Enhancement of Functionality and Therapeutic Efficacy of Cell-Based Therapy Using Mesenchymal Stem Cells for Cardiovascular Disease

Cardiovascular disease usually triggers coronary heart disease, stroke, and ischemic diseases, thus promoting the development of functional failure. Mesenchymal stem cells (MSCs) are cells that can be isolated from various human tissues, with multipotent and immunomodulatory characteristics to help damaged tissue repair and avoidance of immune responses. Much research has proved the feasibility, safety, and efficiency of MSC-based therapy for cardiovascular disease. Despite the fact that the precise mechanism of MSCs remains unclear, their therapeutic capability to treat ischemic diseases has been tested in phase I/II clinical trials. MSCs have the potential to become an effective therapeutic strategy for the treatment of ischemic and non-ischemic cardiovascular disorders. The molecular mechanism underlying the efficacy of MSCs in promoting engraftment and accelerating the functional recovery of injury sites is still unclear. It is hypothesized that the mechanisms of paracrine effects for the cardiac repair, optimization of the niche for cell survival, and cardiac remodeling by inflammatory control are involved in the interaction between MSCs and the damaged myocardial environment. This review focuses on recent experimental and clinical findings related to cardiovascular disease. We focus on MSCs, highlighting their roles in cardiovascular disease repair, differentiation, and MSC niche, and discuss their therapeutic efficacy and the current status of MSC-based cardiovascular disease therapies.

Regulation of Type 2 Immunity in Myocardial Infarction

Type 2 immunity participates in the pathogeneses of helminth infection and allergic diseases. Emerging evidence indicates that the components of type 2 immunity are also involved in maintaining metabolic hemostasis and facilitating the healing process after tissue injury. Numerous preclinical studies have suggested regulation of type 2 immunity-related cytokines, such as interleukin-4, -13, and -33, and cell types, such as M2 macrophages, mast cells, and eosinophils, affects cardiac functions after myocardial infarction (MI), providing new insights into the importance of immune modulation in the infarcted heart. This review provides an overview of the functions of these cytokines and cells in the setting of MI as well as their potential to predict the severity and prognosis of MI.

Immunomodulatory Functions of Mesenchymal Stem Cells in Tissue Engineering

The inflammatory response to chronic injury affects tissue regeneration and has become an important factor influencing the prognosis of patients. In previous stem cell treatments, it was revealed that stem cells not only have the ability for direct differentiation or regeneration in chronic tissue damage but also have a regulatory effect on the immune microenvironment. Stem cells can regulate the immune microenvironment during tissue repair and provide a good "soil" for tissue regeneration. In the current study, the regulation of immune cells by mesenchymal stem cells (MSCs) in the local tissue microenvironment and the tissue damage repair mechanisms are revealed. The application of the concepts of "seed" and "soil" has opened up new research avenues for regenerative medicine. Tissue engineering (TE) technology has been used in multiple tissues and organs using its biomimetic and cellular cell abilities, and scaffolds are now seen as an important part of building seed cell microenvironments. The effect of tissue engineering techniques on stem cell immune regulation is related to the shape and structure of the scaffold, the preinflammatory microenvironment constructed by the implanted scaffold, and the material selection of the scaffold. In the application of scaffold, stem cell technology has important applications in cartilage, bone, heart, and liver and other research fields. In this review, we separately explore the mechanism of MSCs in different tissue and organs through immunoregulation for tissue regeneration and MSC combined with 3D scaffolds to promote MSC immunoregulation to repair damaged tissues.

Circumferential Esophageal Replacement by a Tissue-engineered Substitute Using Mesenchymal Stem Cells: An Experimental Study in Mini Pigs

Tissue engineering appears promising as an alternative technique for esophageal replacement. Mesenchymal stem cells (MSCs) could be of interest for esophageal regeneration. Evaluation of the ability of an acellular matrix seeded with autologous MSCs to promote tissue remodeling toward an esophageal phenotype after circumferential replacement of the esophagus in a mini pig model. A 3 cm long circumferential replacement of the abdominal esophagus was performed with an MSC-seeded matrix (MSC group, n = 10) versus a matrix alone (control group, n = 10), which has previously been matured into the great omentum. The graft area was covered with an esophageal removable stent. A comparative histological analysis of the graft area after animals were euthanized sequentially is the primary outcome of the study. Histological findings after maturation, overall animal survival, and postoperative morbidity were also compared between groups. At postoperative day 45 (POD 45), a mature squamous epithelium covering the entire surface of the graft area was observed in all the MSC group specimens but in none of the control group before POD 95. Starting at POD 45, desmin positive cells were seen in the graft area in the MSC group but never in the control group. There were no differences between groups in the incidence of surgical complications and postoperative death. In this model, MSCs accelerate the mature re-epitheliazation and early initiation of muscle cell colonization. Further studies will focus on the use of cell tracking tools in order to analyze the becoming of these cells and the mechanisms involved in this tissue regeneration.

Allogeneic Mesenchymal Stem Cells and Biomaterials: The Perfect Match for Cardiac Repair?

Coronary heart disease is the leading cause of death worldwide with huge socio-economic consequences. Cell therapy, and particularly mesenchymal stem cells (MSC), are considered a promising option to treat this disorder, due to their robust trophic and immunomodulatory properties. However, limitations such as their low rate of engraftment and poor survival after administration into the heart have precluded their large-scale clinical use. Nevertheless, the combination of MSC with polymer-made scaffolds or hydrogels has proven to enhance their retention and, therefore, their efficacy. Additionally, their allogeneic use could permit the creation of ready-to-use cell patches able to improve their feasibility and promote their application in clinical settings. In this review, the experimental and clinical results derived from the use of MSC in cardiac pathology, as well as advances in the bioengineering field to improve the potential of therapeutic cells, are extensively discussed. Additionally, the current understanding of the heart response to the allogeneic MSC transplants is addressed.

Self-assembling peptide hydrogel enables instant epicardial coating of the heart with mesenchymal stromal cells for the treatment of heart failure

Transplantation of mesenchymal stromal cells (MSCs) is an emerging therapy for the treatment of heart failure. However, the delivery method of MSC is currently suboptimal. The use of self-assembling peptide hydrogels, including PuraMatrix® (PM; 3-D Matrix, Ltd), has been reported for clinical hemostasis and in research models. This study demonstrates the feasibility and efficacy of an advanced approach for MSC-therapy, that is coating of the epicardium with the instantly-produced PM hydrogel incorporating MSCs (epicardial PM-MSC therapy). We optimized the conditions/procedure to produce "instant" 2PM-MSC complexes. After spreading on the epicardium by easy pipetting, the PM-MSC complex promptly and stably adhere to the beating heart. Of note, this treatment achieved more extensive improvement of cardiac function, with greater initial retention and survival of donor MSCs, compared to intramyocardial MSC injection in rat heart failure models. This enhanced efficacy was underpinned by amplified myocardial upregulation of a group of tissue repair-related genes, which led to enhanced repair of the damaged myocardium, i.e. augmented microvascular formation and reduced interstitial fibrosis. These data suggest a potential for epicardial PM-MSC therapy to be a widely-adopted treatment of heart failure. This approach may also be useful for treating diseases in other organs than the heart.

Establishing Early Functional Perfusion and Structure in Tissue Engineered Cardiac Constructs

Myocardial infarction (MI) causes massive heart muscle death and remains a leading cause of death in the world. Cardiac tissue engineering aims to replace the infarcted tissues with functional engineered heart muscles or revitalize the infarcted heart by delivering cells, bioactive factors, and/or biomaterials. One major challenge of cardiac tissue engineering and regeneration is the establishment of functional perfusion and structure to achieve timely angiogenesis and effective vascularization, which are essential to the survival of thick implants and the integration of repaired tissue with host heart. In this paper, we review four major approaches to promoting angiogenesis and vascularization in cardiac tissue engineering and regeneration: delivery of pro-angiogenic factors/molecules, direct cell implantation/cell sheet grafting, fabrication of prevascularized cardiac constructs, and the use of bioreactors to promote angiogenesis and vascularization. We further provide a detailed review and discussion on the early perfusion design in nature-derived biomaterials, synthetic biodegradable polymers, tissue-derived acellular scaffolds/whole hearts, and hydrogel derived from extracellular matrix. A better understanding of the current approaches and their advantages, limitations, and hurdles could be useful for developing better materials for future clinical applications.

Effects of adipose stem cell sheets on colon anastomotic leakage in an experimental model: Proof of principle

The most dreaded complication of colorectal surgery is anastomotic leakage. Adipose tissue-derived stem cell sheets (ASC sheets) prepared from temperature-responsive culture surfaces can be easily transplanted onto tissues. These sheets are proposed to improve cell transplant efficiency and enhance wound healing. The aim of this study was to investigate whether application of ASC sheets could prevent leakage of sutured colorectal anastomoses. Insufficient suturing of colorectal anastomoses was performed in Wistar rats to create a colorectal anastomotic leakage model. Rats were randomized to ASC sheet application or control group. Leakage, abscess formation, adhesion formation, anastomotic bursting pressure (ABP), and histology were evaluated on postoperative day 3 or 7. ASC sheet application significantly reduced anastomotic leakage compared to controls, without increased adhesion formation. ASC sheet transplantation resulted in more CD3+ T-cells and CD163+ anti-inflammatory macrophages at the anastomotic site than the control group. ABP, vessel density and collagen deposition were not different between groups. Using cell sheet technology, we generated ASC sheets that prevented disruption of sutured colorectal anastomoses as shown by reduced leakage. Increased numbers of anti-inflammatory macrophages and T-cells might have contributed to this positive effect.

Antifibrotic Activity of Human Placental Amnion Membrane-Derived CD34+ Mesenchymal Stem/Progenitor Cell Transplantation in Mice With Thioacetamide-Induced Liver Injury

: Liver fibrosis represents the end stage of chronic liver inflammatory diseases and is defined by the abnormal accumulation of extracellular matrix in the liver. Advanced liver fibrosis results in cirrhosis, liver failure, and portal hypertension. Liver transplantation has been the most effective treatment for these diseases, but the procedure is limited by the shortage of suitable donors. Mesenchymal stromal cells (MSCs) have shown great potential in the treatment of chronic inflammatory diseases associated with fibrosis. This study aimed to evaluate the therapeutic effect of MSC-based cell transplantation as an alternative treatment for liver fibrosis. A CD34-positive subpopulation of human placental amnion membrane-derived stem/progenitor cells (CD34⁺ AMSPCs) was isolated through the depletion of CD34-negative stromal fibroblasts (CD34^- AMSFCs) facilitated by CD34 fluorescence-activated cell sorting, enriched and expanded ex vivo. These cells express pluripotency markers and demonstrate multidirectional differentiation potentials. Comparative analysis was made between CD34⁺ AMSPCs and CD34^- AMSFCs in terms of the expressions of stemness surface markers, embryonic surface antigens, and multilineage differentiation potentials. A mouse model of liver fibrosis was established by thioacetamide (TAA) administration. When injected into the spleen of TAA-injured mice, human placental amnion membrane-derived MSCs (hAM-MSCs) can engraft into the injury site, ameliorate liver fibrosis, and restore liver function, as shown by pathological and blood biochemical analysis and downregulated gene expressions associated with liver damage. CD34⁺ AMSPCs represent a more primitive subset of hAM-MSCs and could be a suitable candidate with a potentially better safety profile for cell-based therapy in treatment of liver diseases associated with fibrosis.

SIGNIFICANCE

In this study, a CD34⁺ subpopulation of stem/progenitor cells derived from neonatal placental amnion membrane, denoted as CD34⁺ AMSPCs, were identified, enriched, and characterized. These cells are highly proliferative, express mesenchymal stromal cells and pluripotent stem cell markers, and demonstrate multidirectional differentiation potentials, indicating their promising application in clinical regenerative therapies. CD34⁺ AMSPC transplantation ameliorated liver fibrosis in mice with drug-induced liver injury. These cells represent a potential therapeutic agent for treating liver diseases associated with fibrosis.

Will stem cells bring hope to pathological skin scar treatment?

Pathological skin scars, such as keloids, aesthetically and psychosocially affect patients. The quest for scar reduction and the increasing recognition of patient satisfaction has led to the continued exploration of scar treatment. Stem cells are a promising source for tissue repair and regeneration. The multi-potency and secretory functions of these cells could offer possible treatments for pathological scars and have been examined in recent studies. Here, we analyze the factors that influence the formation of pathological skin scars, summarize recent research on pathological scar treatment with stem cells and elaborate on the possible mechanisms of this treatment. Additionally, other effects of stem cell treatments are also presented while evaluating potential side effects of stem cell-based pathological scar treatments. Thus, this review may provide meaningful guidance in the clinic for scar treatments with stem cells.

Stem Cell Therapy: Current Applications and Potential for Urology

Stem cell therapy holds the potential to revolutionize the treatment of a number of chronic conditions. Stem cells ability to home in on injured sites of the body, stimulate angiogenesis, tissue regeneration, immunomodulation, anti-inflammatory, and anti-fibrotic factors have attracted their use in the treatment of many conditions. Urology has registered one of the highest experimental successes using stem cell therapy. However, the rate of clinical applications is comparatively lower. This review takes a look at our efforts so far and what needs to be done in order to maximize the clinical benefit we can derive from stem cells.

Mesenchymal Stromal Cells Affect Disease Outcomes via Macrophage Polarization

Mesenchymal stromal cells (MSCs) are multipotent and self-renewable cells that reside in almost all postnatal tissues. In recent years, many studies have reported the effect of MSCs on the innate and adaptive immune systems. MSCs regulate the proliferation, activation, and effector function of T lymphocytes, professional antigen presenting cells (dendritic cells, macrophages, and B lymphocytes), and NK cells via direct cell-to-cell contact or production of soluble factors including indoleamine 2,3-dioxygenase, prostaglandin E2, tumor necrosis factor-α stimulated gene/protein 6, nitric oxide, and IL-10. MSCs are also able to reprogram macrophages from a proinflammatory M1 phenotype toward an anti-inflammatory M2 phenotype capable of regulating immune response. Because of their capacity for differentiation and immunomodulation, MSCs have been used in many preclinical and clinical studies as possible new therapeutic agents for the treatment of autoimmune, degenerative, and inflammatory diseases. In this review, we discuss the central role of MSCs in macrophage polarization and outcomes of diseases such as wound healing, brain/spinal cord injuries, and diseases of heart, lung, and kidney in animal models.

Could cancer and infection be adverse effects of mesenchymal stromal cell therapy?

Multipotent mesenchymal stromal cells [also referred to as mesenchymal stem cells (MSCs)] are a heterogeneous subset of stromal cells. They can be isolated from bone marrow and many other types of tissue. MSCs are currently being tested for therapeutic purposes (i.e., improving hematopoietic stem cell engraftment, managing inflammatory diseases and regenerating damaged organs). Their tropism for tumors and inflamed sites and their context-dependent potential for producing trophic and immunomodulatory factors raises the question as to whether MSCs promote cancer and/or infection. This article reviews the effect of MSCs on tumor establishment, growth and metastasis and also susceptibility to infection and its progression. Data published to date shows a paradoxical effect regarding MSCs, which seems to depend on isolation and expansion, cells source and dose and the route and timing of administration. Cancer and infection may thus be adverse or therapeutic effects arising form MSC administration.

Coenzyme Q10 inhibits the aging of mesenchymal stem cells induced by D-galactose through Akt/mTOR signaling

Increasing evidences indicate that reactive oxygen species are the main factor promoting stem cell aging. Recent studies have demonstrated that coenzyme Q10 (CoQ10) plays a positive role in organ and cellular aging. However, the potential for CoQ10 to protect stem cell aging has not been fully evaluated, and the mechanisms of cell senescence inhibited by CoQ10 are still poorly understood. Our previous study had indicated that D-galactose (D-gal) can remarkably induce mesenchymal stem cell (MSC) aging through promoting intracellular ROS generation. In this study, we showed that CoQ10 could significantly inhibit MSC aging induced by D-gal. Moreover, in the CoQ10 group, the expression of p-Akt and p-mTOR was clearly reduced compared with that in the D-gal group. However, after Akt activating by CA-Akt plasmid, the senescence-cell number in the CoQ10 group was significantly higher than that in the control group. These results indicated that CoQ10 could inhibit D-gal-induced MSC aging through the Akt/mTOR signaling.

Bone marrow-derived multipotent stromal cells promote myocardial fibrosis and reverse remodeling of the left ventricle

Cell therapy is increasingly recognized as a beneficial practice in various cardiac conditions, but its fundamentals remain largely unclear. The fates of transplanted multipotent stromal cells in postinfarction cardiac microenvironments are particularly understudied. To address this issue, labeled multipotent stromal cells were infused into rat myocardium at day 30 after myocardial infarction, against the background of postinfarction cardiosclerosis. Therapeutic effects of the transplantation were assessed by an exercise tolerance test. Histological examination at 14 or 30 days after the transplantation was conducted by means of immunostaining and quantitative image analysis. An improvement in the functional status of the cardiovascular system was observed after both the autologous and the allogeneic transplantations. Location of the label-positive cells within the heart was restricted to the affected part of myocardium. The transplanted cells could give rise to fibroblasts or myofibroblasts but not to cardiac myocytes or blood vessel cells. Both types of transplantation positively influenced scarring processes, and no expansion of fibrosis to border myocardium was observed. Left ventricular wall thickening associated with reduced dilatation index was promoted by transplantation of the autologous cells. According to the results, multipotent stromal cell transplantation prevents adverse remodeling and stimulates left ventricular reverse remodeling.

Management of fibrosis: the mesenchymal stromal cells breakthrough

Fibrosis is the endpoint of many chronic inflammatory diseases and is defined by an abnormal accumulation of extracellular matrix components. Despite its slow progression, it leads to organ malfunction. Fibrosis can affect almost any tissue. Due to its high frequency, in particular in the heart, lungs, liver, and kidneys, many studies have been conducted to find satisfactory treatments. Despite these efforts, current fibrosis management therapies either are insufficiently effective or induce severe adverse effects. In the light of these facts, innovative experimental therapies are being investigated. Among these, cell therapy is regarded as one of the best candidates. In particular, mesenchymal stromal cells (MSCs) have great potential in the treatment of inflammatory diseases. The value of their immunomodulatory effects and their ability to act on profibrotic factors such as oxidative stress, hypoxia, and the transforming growth factor-β1 pathway has already been highlighted in preclinical and clinical studies. Furthermore, their propensity to act depending on the microenvironment surrounding them enhances their curative properties. In this paper, we review a large range of studies addressing the use of MSCs in the treatment of fibrotic diseases. The results reported here suggest that MSCs have antifibrotic potential for several organs.

The P75 neurotrophin receptor regulates proliferation of the human MG63 osteoblast cell line

The 75 kDa transmembrane protein, p75(NTR), is a marker of mesenchymal stem cells (MSCs). Isolated MSCs are capable of differentiating into osteoblasts, but the molecular function of p75(NTR) in MSCs and osteoblasts is poorly understood. The aim of this study was to examine the function of p75(NTR) in the human MG63 osteoblast cell line compared to the murine MC3T3E-1 pre-osteoblast cell line. MG63 cells and MC3T3-E1 cells expressing exogenous p75(NTR) protein (denoted as p75-MG63 and p75GFP-E1, respectively) were generated to compare osteogenic differentiation and cell proliferation abilities. Overexpression of p75(NTR) induced alkaline phosphatase activity and the mRNA expression of osteoblast-related genes such as osterix and bone sialoprotein in both p75-MG63 and p75GFP-E1. Interestingly, exogenous p75(NTR) stimulated cell proliferation and cell cycle progression in p75GFP-E1, but not in p75-MG63. To elucidate any different effects of p75(NTR) expression on osteogenic differentiation and cell proliferation, we examined the mRNA expression of tropomyosin receptor kinase (trk) genes (trkA, trkB, trkC) and Nogo receptor (NgR), which are binding partners of p75(NTR). Although trkA, trkB, and trkC were detected in both p75-MG63 and p75GFP-E1, only NgR was detected in p75-MG63. We then used the K252a inhibitor of the trks to identify the signaling pathway for osteogenic differentiation and cell proliferation. Inhibition of trks by K252a suppressed p75(NTR)-mediated osteogenic differentiation of p75GFP-E1, whereas deletion of the GDI domain in P75(NTR) from the p75-MG63 produced enhanced cell proliferation compared to p75-MG63. These results suggest that p75(NTR) signaling associated with trk receptors promotes both cell proliferation and osteoblast differentiation, but that p75(NTR)-mediated proliferation may be suppressed by signaling from the p75(NTR)/NgR complex.

Comparison of angiogenic, cytoprotective, and immunosuppressive properties of human amnion- and chorion-derived mesenchymal stem cells

Although mesenchymal stem cells (MSCs) can be obtained from the fetal membrane (FM), little information is available regarding biological differences in MSCs derived from different layers of the FM or their therapeutic potential. Isolated MSCs from both amnion and chorion layers of FM showed similar morphological appearance, multipotency, and cell-surface antigen expression. Conditioned media obtained from amnion- and chorion-derived MSCs inhibited cell death caused by serum starvation or hypoxia in endothelial cells and cardiomyocytes. Amnion and chorion MSCs secreted significant amounts of angiogenic factors including HGF, IGF-1, VEGF, and bFGF, although differences in the cellular expression profile of these soluble factors were observed. Transplantation of human amnion or chorion MSCs significantly increased blood flow and capillary density in a murine hindlimb ischemia model. In addition, compared to human chorion MSCs, human amnion MSCs markedly reduced T-lymphocyte proliferation with the enhanced secretion of PGE2, and improved the pathological situation of a mouse model of acute graft-versus-host disease. Our results highlight that human amnion- and chorion-derived MSCs, which showed differences in their soluble factor secretion and angiogenic/immuno-suppressive function, could be ideal cell sources for regenerative medicine.