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Mesenchymal stem cell therapy: Two steps forward, one step back

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Abstract

Mesenchymal stem cell (MSC) therapy is poised to establish a new clinical paradigm; however, recent trials have produced mixed results. Although MSC were originally considered to treat connective tissue defects, preclinical studies revealed potent immunomodulatory properties that prompted the use of MSC to treat numerous inflammatory conditions. Unfortunately, although clinical trials have met safety endpoints, efficacy has not been demonstrated. We believe the challenge to demonstrate efficacy can be attributed in part to an incomplete understanding of the fate of MSC following infusion. Here, we highlight the clinical status of MSC therapy and discuss the importance of cell-tracking techniques, which have advanced our understanding of the fate and function of systemically infused MSC and might improve clinical application.

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... [223,224]. In addition, the basic limitation of this therapy is the great number of cells required for transplantation [225][226][227][228][229]. ...
... MSC functionality differs depending on their tissue origin, as it was reported between AT-MSC and BM-MSC regarding the proliferation and differentiation capacity, or paracrine mechanisms, like the secretion of pro-angiogenic factors [176]. With regard to anti-inflammatory effects, heterogeneity of MSC from different sources often secrete varying levels of soluble factors and thus exert diverse suppressive effects [229]. As it was described above, different tissue sources of MSC were employed depending on the clinical application. ...
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Inflammatory bowel diseases (IBD) are an example of chronic diseases affecting 40% of the population, which involved tissue damage and an inflammatory process not satisfactorily controlled with current therapies. Data suggest that mesenchymal stem cells (MSC) may be a therapeutic option for these processes, and especially for IBD, due to their multifactorial approaches such as anti-inflammatory, anti-oxidative stress, anti-apoptotic, anti-fibrotic, regenerative, angiogenic, anti-tumor, or anti-microbial. However, MSC therapy is associated with important limitations as safety issues, handling difficulties for therapeutic purposes, and high economic cost. MSC-derived secretome products (conditioned medium or extracellular vesicles) are therefore a therapeutic option in IBD as they exhibit similar effects to their parent cells and avoid the issues of cell therapy. In this review, we proposed further studies to choose the ideal tissue source of MSC to treat IBD, the implementation of new standardized production strategies, quality controls and the integration of other technologies, such as hydrogels, which may improve the therapeutic effects of derived-MSC secretome products in IBD.
... 3. Sources of Stem Cells: There are multitudes of sources of stem cells; however most commonly autologous haemopoietic stem cells, umbilical cord blood stem cells or umbilical cord derived stem cells are extensively used. Mesenchymal Stem Cells (MSCs) can have multitude of uses and some companies have tried to produce off the shelf material (Ankrum, 2010). 6 However again details of such therapeutic approach and its scope needs to be developed in the form of guidelines when the data matures. ...
... Mesenchymal Stem Cells (MSCs) can have multitude of uses and some companies have tried to produce off the shelf material (Ankrum, 2010). 6 However again details of such therapeutic approach and its scope needs to be developed in the form of guidelines when the data matures. Ownership of such kind of stem cells also has ethical and financial dimensions. ...
... 31 In addition, MSCs have been shown to express high levels of tumor necrosis factor-inducible gene 6 (TSG-6), which functions to inhibit neutrophil migration as well as MMP production and activity. 32 These immunomodulatory properties are pronounced to such a degree that MSCs have been used to significantly improve outcomes of immune-driven disorders, such as graft-versus-host disease. 32 Other diseases, such as MI, have also benefitted from a type of placental-derived MSC. 1 Therefore, it is thought that immune modulation via MSCs could improve the underlying inflammation linked to HFpEF progression. 1 MSCs are also cardioprotective candidates for HFpEF due to their tissue regeneration properties. ...
... 32 These immunomodulatory properties are pronounced to such a degree that MSCs have been used to significantly improve outcomes of immune-driven disorders, such as graft-versus-host disease. 32 Other diseases, such as MI, have also benefitted from a type of placental-derived MSC. 1 Therefore, it is thought that immune modulation via MSCs could improve the underlying inflammation linked to HFpEF progression. 1 MSCs are also cardioprotective candidates for HFpEF due to their tissue regeneration properties. MSCs are capable of migrating to inflamed tissue and secreting cytokines and growth factors that reduce apoptosis and decrease tissue injury. ...
Article
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Heart failure with preserved ejection fraction (HFpEF) is characterized by a left ventricular ejection fraction of 50% or greater. While heart failure with reduced ejection fraction (HFrEF) is well-characterized and has numerous treatment options, HFpEF remains poorly understood. HFpEF has long been termed diastolic dysfunction , because it was thought that fibrosis and impaired relaxation of the left ventricle could alone explain the underlying pathophysiology. However, recent research has identified additional mechanisms that influence HFpEF, specifically metabolic disorders and proinflammatory conditions. Despite this recent progress in elucidating the pathophysiology, there are still no approved treatment options that increase survival in patients with HFpEF. In the context of limited pharmacological options, stem cell therapy and cardiac biomarkers have emerged as potential breakthroughs in the treatment of HFpEF, but there has not yet been a review of their potential. This review evaluates the potential of cardiosphere-derived cells (CDCs), mesenchymal stromal cells (MSCs), and endothelial progenitor cells (EPCs) in the treatment of HFpEF. CDCs have shown promise, with a placebo-controlled animal trial demonstrating an increase in survival and a marked improvement in left ventricular end diastolic filling among the group treated with intracoronary infusion of CDCs. Additionally, with the newfound understanding of HFpEF pathophysiology, studies have also investigated the role MSCs and EPCs play in the inflammation associated with HFpEF, as well as the potential benefit these stem cells would bring to the treatment of HFpEF. While clinical trials are needed to confirm the safety and efficacy of these therapies, we offer insight into their potential, as well as a comprehensive summary of the pertinent clinical studies that are currently in progress. Embase, Ovid Medline, and PubMed were used to search all relevant literature for this review.
... For some years now, developments in medicine have applied human stem cell therapy to treat tissue-related conditions. Mesenchymal stem cells (MSCs) are a heterogeneous population of pluripotent progenitor cells that can be isolated and expanded in vitro from different adult tissues [3,4] and are the most widely used stem cells in scientific research and clinical applications. MSCs have also been investigated as a novel therapy given their anti-inflammatory and tissue regenerative potential [5][6][7][8][9][10][11]. ...
Article
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Background/Aims Mesenchymal stem cells (MSCs) are a type of adult pluripotent stem cell that has anti-inflammatory and immunomodulatory effects, and whose conditioned medium (CM) has also been found to be effective. We used MSC and CM enemas to investigate their ameliorative effects in a mouse model of colitis. Methods We employed MSCs, CM, and MSCs + ML385 (an inhibitor of Nrf2) in dextran sodium sulfate (DSS)-induced colitis. Mice were sacrificed on day 8, and the effects of MSC or CM treatment on the levels of inflammation and oxidative stress in colonic epithelial cells were evaluated by histological analyses. Results MSCs inhibited inflammatory cell infiltration and proinflammatory cytokine expression in the colon. In addition, MSCs reduced extracellular matrix deposition and maintained the mechanical barrier and permeability of colonic epithelial cells. Mechanistically, MSCs activated Nrf2, which then increased HO-1 and NQO-1 levels and downregulated the expression of Keap1 to suppress reactive oxygen species production and MDA generation, accompanied by increases in components of the enzymatic antioxidant system, including SOD, CAT, GSH-Px, and T-AOC. However, after administering an Nrf2 inhibitor (ML385) to block the Nrf2/Keap1/ARE pathway, we failed to observe protective effects of MSCs in mice with colitis. CM alone also produced some of the therapeutic benefits of MSCs but was not as effective as MSCs. Conclusions Our data confirmed that MSCs and CM can effectively improve intestinal mucosal repair in experimental colitis and that MSCs can improve this condition by activating the Nrf2/Keap1/ARE pathway.
... Enfin, l'analyse histologique des tissus après le sacrifice de l'animal permet d'apporter des informations complémentaires sur la localisation des MSC chez l'animal receveur. La limite des techniques d'imagerie d'animal entier, telles que la bioluminescence est la faible résolution qui ne permet pas d'identifier si les MSC restent dans le système vasculaire ou migrent à l'extérieur [349]. Il est important de valider in vitro que les différentes méthodes de marquages ne modifient pas les propriétés des MSC. ...
Thesis
Depuis leur première utilisation clinique en 2001 dans l’ostéogénèse imparfaite, l’engouement pour le recours aux cellules stromales mésenchymateuses (MSC) comme approche thérapeutique dans le traitement des désordres dysimmunitaires, en médecine régénératrice et plus récemment dans la prise en charge de patients atteints d’une infection à coronavirus (COVID19) ne cesse d’augmenter. Cependant, des résultats contradictoires dus à la variabilité des procédés de production, à la diversité des patients inclus et des pathologies ciblées perturbent le développement de cette approche thérapeutique. De plus, l’hétérogénéité des MSC elles-mêmes rend difficile leur caractérisation fonctionnelle. Par ailleurs, la phase d’amplification en culture n’est pas associée à un risque de transformation mais peut entraîner une entrée en sénescence qui peut impacter leurs propriétés. Initialement, leur efficacité a été attribuée à leur capacité de différenciation, il est maintenant avéré que c’est leur pouvoir immunorégulateur qui. Dans ce travail, nous avons étudié plusieurs facteurs de variabilité qui jouent un rôle dans l’efficacité thérapeutique des MSC. Tout d’abord, nous avons validé que l’origine tissulaire des MSC impacte fortement leurs propriétés : les MSC dérivées du tissu adipeux ont des fonctions immunorégulatrices plus intéressantes que les MSC dérivées de la moelle osseuse pour leur utilisation thérapeutique. Par ailleurs, nous avons démontré que la capacité à inhiber les lymphocytes T diminue lorsque les MSC entrent en sénescence réplicative en raison d’une augmentation de la dégradation de l’enzyme indoléamine 2,3-dioxygénase par le protéasome. Enfin, nous avons montré que dans un contexte inflammatoire, l’interaction des MSC avec les lymphocytes T CD4 via CD40/CD40L entraîne le recrutement des polynucléaires neutrophiles de façon IL8 dépendante. Ainsi, la source tissulaire, l’amplification en culture et la capacité des MSC à interagir avec les cellules immunitaires sont des paramètres qu’il est important d’évaluer grâce à la mise en place de tests de validation afin d’améliorer l’efficacité des études cliniques.
... A major hurdle to gaining this knowledge is that MSCs lack molecular effectors of cell migration. As such, when systemically administered, cultureexpanded MSCs do not efficiently extravasate at inflammatory sites, and thereby cannot anatomically localize where needed 16 . ...
Article
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Mesenchymal stem/stromal cells (MSCs) are distributed within all tissues of the body. Though best known for generating connective tissue and bone, these cells also display immunoregulatory properties. A greater understanding of MSC cell biology is urgently needed because culture-expanded MSCs are increasingly being used in treatment of inflammatory conditions, especially life-threatening immune diseases. While studies in vitro provide abundant evidence of their immunomodulatory capacity, it is unknown whether tissue colonization of MSCs is critical to their ability to dampen/counteract evolving immunopathology in vivo. To address this question, we employed a murine model of fulminant immune-mediated inflammation, acute graft-versus-host disease (aGvHD), provoked by donor splenocyte-enriched full MHC-mismatched hematopoietic stem cell transplant. aGvHD induced the expression of E-selectin within lesional endothelial beds, and tissue-specific recruitment of systemically administered host-derived MSCs was achieved by enforced expression of HCELL, a CD44 glycoform that is a potent E-selectin ligand. Compared to mice receiving HCELL ⁻ MSCs, recipients of HCELL ⁺ MSCs had increased MSC intercalation within aGvHD-affected site(s), decreased leukocyte infiltrates, lower systemic inflammatory cytokine levels, superior tissue preservation, and markedly improved survival. Mechanistic studies reveal that ligation of HCELL/CD44 on the MSC surface markedly potentiates MSC immunomodulatory activity by inducing MSC secretion of a variety of potent immunoregulatory molecules, including IL-10. These findings indicate that MSCs counteract immunopathology in situ, and highlight a role for CD44 engagement in unleashing MSC immunobiologic properties that maintain/establish tissue immunohomeostasis.
... 60 However, follow-up studies demonstrated that allogenic mesenchymal stem cell transplants still elicited an immune response and graft rejection in the 'immune privileged' CNS. [61][62][63] Furthermore, while mesenchymal stem cells can be transdifferentiated to neuron-like cells in vitro, their ability to recapitulate neurons in vivo after transplantation has been less studied. 64,65 Alternatively, the advent of induced pluripotent stem cell technology brings the promise of autologous cell transplants, but currently these approaches are labour-and cost-intensive and likely to be prohibitive for large clinical trials and population scale therapy. ...
Article
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Background: As the field of stem cell therapy advances, it is important to develop reliable methods to overcome host immune responses in animal models. This ensures survival of transplanted human stem cell grafts and enables predictive efficacy testing. Immunosuppressive drugs derived from clinical protocols are frequently used but are often inconsistent and associated with toxic side effects. Here, using a molecular imaging approach, we show that immunosuppression targeting costimulatory molecules CD4 and CD40L enables robust survival of human xenografts in mouse brain, as compared to conventional tacrolimus and mycophenolate mofetil. Methods: Human neural stem cells were modified to express green fluorescent protein and firefly luciferase. Cells were implanted in the fimbria fornix of the hippocampus and viability assessed by non-invasive bioluminescent imaging. Cell survival was assessed using traditional pharmacologic immunosuppression as compared to monoclonal antibodies directed against CD4 and CD40L. This paradigm was also implemented in a transgenic Alzheimer's disease mouse model. Results: Graft rejection occurs within 7 days in non-immunosuppressed mice and within 14 days in mice on a traditional regimen. The addition of dual monoclonal antibody immunosuppression extends graft survival past 7 weeks (p < .001) on initial studies. We confirm dual monoclonal antibody treatment is superior to either antibody alone (p < .001). Finally, we demonstrate robust xenograft survival at multiple cell doses up to 6 months in both C57BL/6J mice and a transgenic Alzheimer's disease model (p < .001). The dual monoclonal antibody protocol demonstrated no significant adverse effects, as determined by complete blood counts and toxicity screen. Conclusions: This study demonstrates an effective immunosuppression protocol for preclinical testing of stem cell therapies. A transition towards antibody-based strategies may be advantageous by enabling stem cell survival in preclinical studies that could inform future clinical trials.
... However, the number of trials has steadily decreased since 2018 [25], as it has become an issue to reach phase III trials. Although phase I and phase II trials have shown some beneficial effects, the question still surrounds the fate of MSCs after administration [26,27]. ...
Article
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Human-adipose-derived mesenchymal stem cells (hADMSCs) are multipotent stem cells which have become of great interest in stem-cell therapy due to their less invasive isolation. However, they have limited migration and short lifespans. Therefore, understanding the mechanisms by which these cells could migrate is of critical importance for regenerative medicine. Methods: Looking for novel alternatives, herein, hADMSCs were isolated from adipose tissue and co-cultured with human monocytes ex vivo. Results: A new fused hybrid entity, a foam hybrid cell (FHC), which was CD90+CD14+, resulted from this co-culture and was observed to have enhanced motility, proliferation, immunomodulation properties, and maintained stemness features. Conclusions: Our study demonstrates the generation of a new hybrid cellular population that could provide migration advantages to MSCs, while at the same time maintaining stemness properties.
... The major conclusion of these studies and trials is that MSC-based therapy is safe, although the outcomes have usually been either neutral or at best marginally positive in terms of the clinically relevant endpoints regardless of MSC tissue origin, route of infusion, dose, administration duration, and preconditioning. 136 It is important to note that a solid background of knowledge has been generated from all these studies that has fueled the recent translational research in MSC-based therapy. As MSCs have been intensively studied over the last 55 years and have become the subject of multiple reviews, systematic reviews, and metaanalyses, the objective of this paper is not to duplicate these publications. ...
Article
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Recent advancements in stem cell technology open a new door for patients suffering from diseases and disorders that have yet to be treated. Stem cell-based therapy, including human pluripotent stem cells (hPSCs) and multipotent mesenchymal stem cells (MSCs), has recently emerged as a key player in regenerative medicine. hPSCs are defined as self-renewable cell types conferring the ability to differentiate into various cellular phenotypes of the human body, including three germ layers. MSCs are multipotent progenitor cells possessing self-renewal ability (limited in vitro) and differentiation potential into mesenchymal lineages, according to the International Society for Cell and Gene Therapy (ISCT). This review provides an update on recent clinical applications using either hPSCs or MSCs derived from bone marrow (BM), adipose tissue (AT), or the umbilical cord (UC) for the treatment of human diseases, including neurological disorders, pulmonary dysfunctions, metabolic/endocrine-related diseases, reproductive disorders, skin burns, and cardiovascular conditions. Moreover, we discuss our own clinical trial experiences on targeted therapies using MSCs in a clinical setting, and we propose and discuss the MSC tissue origin concept and how MSC origin may contribute to the role of MSCs in downstream applications, with the ultimate objective of facilitating translational research in regenerative medicine into clinical applications. The mechanisms discussed here support the proposed hypothesis that BM-MSCs are potentially good candidates for brain and spinal cord injury treatment, AT-MSCs are potentially good candidates for reproductive disorder treatment and skin regeneration, and UC-MSCs are potentially good candidates for pulmonary disease and acute respiratory distress syndrome treatment.
... Mesenchymal Stem Cells (MSCs) show strong regenerative and immunoregulatory potential, and are tested as cell-based therapies for a wide range of diseases. 1,2 Owing to their differentiation potential into clinically relevant lineages such as osteocytes, chondrocytes, and adipocytes and their immunomodulatory role, MSCs are widely studied and have been shown to display considerable spatial and temporal molecular heterogeneity. 3 MSCs are isolated from barcoded substrates and microbeads to capture multiple RNA targets, providing gene expression maps of tissues at 10-100 µm resolutions. ...
Preprint
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Mesenchymal stem cell (MSC)-based therapies have offered promising treatments against several disorders. However, the clinical efficacy and consistency remain underdeveloped. Single-cell and bulk molecular analyses have provided considerable heterogeneity of MSCs due to origin, expansion, and microenvironment. Image-based cellular omics methods elucidate ultimate variability in stem cell colonies, otherwise masked by bulk omics approaches. Here, we present a spatially resolved Gene Neighborhood Network (spaGNN) method to produce transcriptional density maps and analyze neighboring RNA distributions in single human MSCs and chondrocytes cultured on 2D collagen-coated substrates. This proposed strategy provides cell classification based on subcellular spatial features and gene neighborhood networks. Machine learning-based clustering of resultant data yields subcellular density classes of 20-plex biomarkers containing diverse transcript and protein features. The spaGNN reveals tissue-source-specific MSC transcription and spatial distribution characteristics. Multiplexed spaGNN analysis allows for rapid examination of spatially resolved subcellular features and activities in a broad range of cells used in pre-clinical and clinical research.
... More than 1000 registered clinical trials have explored MSCs for nearly every clinical application, including neurodegenerative and cardiac disorders, GvHD, COVID-19, and cancer. However, most clinical MSC therapies have not met primary efficacy endpoints in clinical trials 123,124 . Given this context, regulators have issued multiple guidance documents for pharmaceutical companies in the cell therapy field in recent years to improve potency and safety assays, which should start at the earliest stages of product development 8,[125][126][127][128][129][130][131] . ...
Article
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Cell therapies have emerged as a promising new class of “living” therapeutics over the last decade and have been particularly successful for treating hematological malignancies. Increasingly, cellular therapeutics are being developed with the aim of treating almost any disease, from solid tumors and autoimmune disorders to fibrosis, neurodegenerative disorders and even aging itself. However, their therapeutic potential has remained limited due to the fundamental differences in how molecular and cellular therapies function. While the structure of a molecular therapeutic is directly linked to biological function, cells with the same genetic blueprint can have vastly different functional properties (e.g., secretion, proliferation, cell killing, migration). Although there exists a vast array of analytical and preparative separation approaches for molecules, the functional differences among cells are exacerbated by a lack of functional potency-based sorting approaches. In this context, we describe the need for next-generation single-cell profiling microtechnologies that allow the direct evaluation and sorting of single cells based on functional properties, with a focus on secreted molecules, which are critical for the in vivo efficacy of current cell therapies. We first define three critical processes for single-cell secretion-based profiling technology: (1) partitioning individual cells into uniform compartments; (2) accumulating secretions and labeling via reporter molecules; and (3) measuring the signal associated with the reporter and, if sorting, triggering a sorting event based on these reporter signals. We summarize recent academic and commercial technologies for functional single-cell analysis in addition to sorting and industrial applications of these technologies. These approaches fall into three categories: microchamber, microfluidic droplet, and lab-on-a-particle technologies. Finally, we outline a number of unmet needs in terms of the discovery, design and manufacturing of cellular therapeutics and how the next generation of single-cell functional screening technologies could allow the realization of robust cellular therapeutics for all patients.
... Significant progress in myocardial injury repair [56], angiogenesis [57] and spinal cord injury repair [58,59] has been made using BMSCs, and preclinical research on these cells has also been carried out [60]. However, differences in culture conditions, the cell course, passage methods and cell density affect the BMSCs phenotype, and the expected results were not observed in preclinical studies [61]. This may be related to impairment of cell function and an increase in cell death caused by a poor disease microenvironment [62,63]. ...
Article
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Background Bone marrow mesenchymal stem cell (BMSCs) therapy is an important cell transplantation strategy in the regenerative medicine field. However, a severely ischemic microenvironment, such as nutrient depletion and hypoxia, causes a lower survival rate of transplanted BMSCs, limiting the application of BMSCs. Therefore, improving BMSCs viability in adverse microenvironments is an important means to improve the effectiveness of BMSCs therapy. Objective To illustrate the protective effect of andrographolide (AG) against glucose and serum deprivation under hypoxia (1% O 2 ) (GSDH)-induced cell injury in BMSCs and investigate the possible underlying mechanisms. Methods An in vitro primary rat BMSCs cell injury model was established by GSDH, and cellular viability, proliferation and apoptosis were observed after AG treatment under GSDH. Reactive oxygen species levels and oxidative stress-related genes and proteins were measured by flow cytometry, RT-qPCR and Western blotting. Mitochondrial morphology, function and number were further assessed by laser confocal microscopy and flow cytometry. Results AG protected BMSCs against GSDH-induced cell injury, as indicated by increases in cell viability and proliferation and mitochondrial number and decreases in apoptosis and oxidative stress. The metabolic status of BMSCs was changed from glycolysis to oxidative phosphorylation to increase the ATP supply. We further observed that the NRF2 pathway was activated by AG, and treatment of BMSCs with a specific NRF2 inhibitor (ML385) blocked the protective effect of AG. Conclusion Our results suggest that AG is a promising agent to improve the therapeutic effect of BMSCs.
... Cell therapy is an emerging paradigm of medical treatment that uses cells to treat a broad array of acute and chronic diseases (Ankrum and Karp 2010;Anguille et al. 2014;Holzinger et al. 2016). Most cell therapy products are made using typical bench cell culture techniques performed inside of a clean room. ...
Article
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Cell therapy is an emerging field that uses cells as living drugs to treat a broad array of acute and chronic diseases. Most cell therapies in clinical trials are made using standard bench methods, whose open processing require manufacturing in expensive GMP cleanrooms. As cell therapies progress, new methods are needed to enable scalable manufacturing while maintaining process integrity, reducing environmental exposure, and limiting critical cell and reagent use. Here, we introduce capture and reagent exchange (CARE) wells that allow critical processing steps to be integrated into a closed microfluidic device. The unique property of CARE wells is that they allow reagent exchange from an attached channel without cell loss from wells. We show through simulation and experiment that this feature is present in cylindrical wells whose depth is sufficient to generate multiple recirculating vortices and is independent of flow rate in the channel. We demonstrate that CARE wells can be used to perform cell separation, on-chip labeling, and characterization of monocytes as the first steps toward a closed microfluidic system for production of dendritic cell therapies. Immunomagnetic separation of CD14 + monocytes from peripheral blood mononuclear cells (PBMCs) into wells was performed with purity of 97 ± 2% and capture efficiency of 50 ± 17%. On-chip labeling, washing, and characterization were performed using two cell surface markers (CD14 and HLA-DR) on over 3000 cells captured in a 5193-well device. The combination of high purity separation and reagent exchange without cell loss with robust performance over wide range of input and operating conditions makes this technique a promising approach for scalable manufacturing and analysis of cell therapies.
... The pro-reparative effects of uterine stem cells are widely attributed to paracrine mechanisms [113,114]. In fact, the paracrine properties of such cells has resulted in them being widely investigated in clinical trials for treating heart failure [88]. ...
Article
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Clinical evidence suggests that the prevalence of cardiac disease is lower in premenopausal women compared to postmenopausal women and men. Although multiple factors contribute to this difference, uterine stem cells may be a major factor, as a high abundance of these cells are present in the uterus. Uterine-derived stem cells have been reported in several studies as being able to contribute to cardiac neovascularization after injury. However, our studies uniquely show the presence of an “utero-cardiac axis”, in which uterine stem cells are able to home to cardiac tissue to promote tissue repair. Additionally, we raise the possibility of a triangular relationship among the bone marrow, uterus, and heart. In this review, we discuss the exchange of stem cells across different organs, focusing on the relationship that exists between the heart, uterus, and bone marrow. We present increasing evidence for the existence of an utero-cardiac axis, in which the uterus serves as a reservoir for cardiac reparative stem cells, similar to the bone marrow. These cells, in turn, are able to migrate to the heart in response to injury to promote healing.
... MSCs have also been found to cause and promote the growth of various types of cancer [69]. In addition, there are the usual associated risks of cell therapy such as viral infection and immune rejection as well as problems with storage and transportation [70]. ...
Article
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Mesenchymal stem cells (MSCs) can be widely isolated from various tissues including bone marrow, umbilical cord, and adipose tissue, with the potential for self-renewal and multipotent differentiation. There is compelling evidence that the therapeutic effect of MSCs mainly depends on their paracrine action. Extracellular vesicles (EVs) are fundamental paracrine effectors of MSCs and play a crucial role in intercellular communication, existing in various body fluids and cell supernatants. Since MSC-derived EVs retain the function of protocells and have lower immunogenicity, they have a wide range of prospective therapeutic applications with advantages over cell therapy. We describe some characteristics of MSC-EVs, and discuss their role in immune regulation and regeneration, with emphasis on the molecular mechanism and application of MSC-EVs in the treatment of fibrosis and support tissue repair. We also highlight current challenges in the clinical application of MSC-EVs and potential ways to overcome the problem of quality heterogeneity.
... In this section, we will first discuss the role of natural exosomes as neurotherapeutics, and toward the end, we will discuss the role of surface engineered novel cargo-loaded exosomes as neurotherapeutics ( Figure 5). Mesenchymal stem cell (MSC) is already extensively studied for regenerative medicine, cell therapy, and tissue engineering (Ankrum and Karp, 2010). Accordingly, research based on exosomes derived from MSCs (MSC-exosomes) has great value as this has the advantage of exosomes and also the characteristics of MSCs (Ghosh et al., 2020). ...
Article
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Exosomes are nanosized “off-the-shelf” lipid vesicles released by almost all cell types and play a significant role in cell–cell communication. Exosomes have already been proven to carry cell-specific cargos of proteins, lipids, miRNA, and noncoding RNA (ribonucleic acid). These vesicles can be selectively taken up by the neighboring cell and can regulate cellular functions. Herein, we have discussed three different roles of exosomes in neuroscience. First, we have discussed how exosomes play the role of a pathogenic agent as a part of cell–cell communication and transmit pathogens such as amyloid-beta (Aβ), further helping in the propagation of neurodegenerative and other neurological diseases. In the next section, the review talks about the role of exosomes in biomarker discovery in neurological disorders. Toward the end, we have reviewed how exosomes can be harnessed and engineered for therapeutic purposes in different brain diseases. This review is based on the current knowledge generated in this field and our comprehension of this domain.
... In addition, several phase III clinical trials have failed due to the inefficiency of BMSCs. Therefore, identification of strategies to improve the therapeutic effects has become a key issue in BMSC therapy (Ankrum and Karp 2010;Liao et al., 2017). In recent studies, traditional Chinese medicine (TCM) combined with BMSC therapy has shown unique advantages and characteristics. ...
Article
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Bone marrow mesenchymal stem cells (BMSCs) can effectively alleviate liver fibrosis, but the efficacy of cell therapy alone is insufficient. In recent years, a combination of traditional Chinese medicine (TCM) and cell therapy has been increasingly used to treat diseases in clinical trials. Ferulic acid (FA) is highly effective in treating liver fibrosis, and a combination of cells and drugs is being tested in clinical trials. Therefore, we combined BMSCs and Ferulic acid to treat CCl4-induced fibrosis and determine whether this combination was more effective than single treatment. We used BMSCs and FA to treat CCl4-induced fibrosis in rat models, observed their therapeutic effects, and investigated the specific mechanism of this combination therapy in liver fibrosis. We created a BMSC/hepatic stellate cell (HSC) coculture system and used FA to treat activated HSCs to verify the specific mechanism. Then, we used cytochalasin D and angiotensin II to investigate whether BMSCs and FA inactivate HSCs through cytoskeletal rearrangement. MiR-19b-3p was enriched in BMSCs and targeted TGF-β receptor II (TGF-βR2). We separately transfected miR-19b-3p into HSCs and BMSCs and detected hepatic stellate cell activation. We found that the expression of the profibrotic markers α-SMA and COL1-A1 was significantly decreased in the combination group of rats. α-SMA and COL1-A1 levels were also significantly decreased in the HSCs with the combination treatment. Cytoskeletal rearrangement of HSCs was inhibited in the combination group, and RhoA/ROCK pathway gene expression was decreased. Following angiotensin II treatment, COL1-A1 and α-SMA expression increased, while with cytochalasin D treatment, profibrotic gene expression decreased in HSCs. The expression of COL1-A1, α-SMA and RhoA/ROCK pathway genes was decreased in the activated HSCs treated with a miR-19b-3p mimic, indicating that miR-19b-3p inactivated HSCs by suppressing RhoA/ROCK signalling. In contrast, profibrotic gene expression was significantly decreased in the BMSCs treated with the miR-19b-3p mimic and FA or a miR-19b-3p inhibitor and FA compared with the BMSCs treated with the miR-19b-3p mimic alone. In conclusion, the combination therapy had better effects than FA or BMSCs alone. BMSC and FA treatment attenuated HSC activation and liver fibrosis by inhibiting cytoskeletal rearrangement and delivering miR-19b-3p to activated HSCs, inactivating RhoA/ROCK signalling. FA-based combination therapy showed better inhibitory effects on HSC activation.
... Generally, antifibrosis treatments may be classified in agents which mediate the anti-fibrosis effects through hepatocyte protection, suppressing the activation of HSCs as well as immune modulation (Roehlen et al. 2020). Mesenchymal stem cells (MSCs) can differentiate into a variety of cell types, including osteoblasts, chondrocytes, and adipocytes, and are considered to be promising tissue remodeling therapeutic agents (Ankrum and Karp 2010). Recent studies have assessed the capacity of MSCs to relieve liver fibrosis and enhance liver function (Eom et al. 2015;Liu et al. 2015). ...
Article
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Objective To investigate the effects of human bone marrow mesenchymal stem cells (hMSCs)-derived exosome circCDK13 on liver fibrosis and its mechanism. Methods Exosomes derived from hMSCs were extracted and identified by flow cytometry and osteogenic and adipogenic induction, and the expressions of marker proteins on the surface of exosomes were detected by western blot. Cell proliferation was measured by CCK8 assay, the expression of active markers of HSCs by immunofluorescence, and the expressions of fibrosis-related factors by western blot. A mouse model of liver fibrosis was established by intraperitoneal injection of thioacetamide (TAA). Fibrosis was detected by HE staining, Masson staining, and Sirius red staining. Western blot was utilized to test the expressions of PI3K/AKT and NF-κB pathway related proteins, dual-luciferase reporter assay and RIP assay to validate the binding between circCDK13 and miR-17-5p as well as between miR-17-5p and KAT2B, and ChIP to validate the effect of KAT2B on H3 acetylation and MFGE8 transcription. Results hMSCs-derived exosomes inhibited liver fibrosis mainly through circCDK13. Dual-luciferase reporter assay and RIP assay demonstrated the binding between circCDK13 and miR-17-5p as well as between miR-17-5p and KAT2B. Further experimental results indicated that circCDK13 mediated liver fibrosis by regulating the miR-17-5p/KAT2B axis, and KAT2B promoted MFGE8 transcription by H3 acetylation. Exo-circCDK13 inhibited PI3K/AKT and NF-κB signaling pathways activation through regulating the miR-17-5p/KAT2B axis. Conclusion hMSCs-derived exosome circCDK13 inhibited liver fibrosis by regulating the expression of MFGE8 through miR-17-5p/KAT2B axis. Graphical abstract
... Currently, systemic delivery, such as the intra-arterial (IA) and intravenous (IV) routes, is commonly used for MSC transplantation in AKI treatment. However, the low renal implantation rate, low cell retention rate and high embolism risk limit IV/IA therapies [11,12]. ...
Article
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Background Mesenchymal stem cells (MSCs) have emerged as a promising cell-based therapy for acute kidney injury (AKI). However, the optimal route of MSC transplantation remains controversial, and there have been no comparisons of the therapeutic benefits of MSC administration through different delivery routes. Methods In this study, we encapsulated MSCs into a collagen matrix to help achieve local MSC retention in the kidney and assessed the survival of MSCs in vitro and in vivo. After transplanting collagen matrix-encapsulated-MSCs (Col-MSCs) under the renal capsule or into the parenchyma using the same cell dose and suspension volume in an ischemia/reperfusion injury model, we evaluated the treatment efficacy of two local transplantation routes at different stages of AKI. Results We found that Col-MSCs could be retained in the kidney for at least 14 days. Both local MSC therapies could reduce tubular injury, promote the proliferation of renal tubular epithelial cells on Day 3 and alleviate renal fibrosis on Day 14 and 28. MSC transplantation via the subcapsular route exerts better therapeutic effects for renal functional and structural recovery after AKI than MSC administration via the parenchymal route. Conclusions Subcapsular MSC transplantation may be an ideal route of MSC delivery for AKI treatment, and collagen I can provide a superior microenvironment for cell–cell and cell–matrix interactions to stabilize the retention rate of MSCs in the kidney.
... It is worth mentioning that the therapeutic outcomes of previous trials have been inconsistent. This could be due to donor to donor variations, differences in route of administration, and differences in assessment criteria (Ankrum and Karp 2010;Perin et al. 2003). It was first believed that cell replacement was the major mechanism by which stem cells exerted their healing activities. ...
Article
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Recent progress in stem cell technology and its successful translation into clinical procedures have shed new light in treating various diseases. Indeed, the past decade witnessed an exponential trend towards clinical trials with stem cell-based therapeutics. Recently, combinations of stem cell technology with other emerging technologies such as nanotechnology, tissue engineering, and biomaterials science have enriched hopes to enhance stem cell’s potential to treat diseases and injuries. The essence of these sciences is the use of a suitable biomaterial for production of a versatile platform on which other functionalities can be integrated. Among various candidates, cellulose-based biomaterials including plant and bacteria-derived cellulose have gained significant attention in stem cell technology. Due to their high availability, low cost, processability, non-immunogenicity, and non-toxic properties, appeal towards the use of these polymers is constantly rising. In the current review, we will discuss the applications, challenges, and prospects of bacteria and plant-derived cellulose in stem cell sciences. Graphical abstract
... 27 Besides, ovarian tissue transplantation and stem cell transplantation can not cure POI, due to their poor prognosis and uncontrollable long-term results. 28 Therefore, it is urgent to find a new clinical treatment strategy for POI patients. ...
Article
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This study is to explore the therapeutic effect and potential mechanisms of exosomal microRNAs (miRNAs) derived from the ovaries with primary ovarian insufficiency (POI). The POI mouse model was established by intraperitoneal injection of cyclophosphamide (CTX) and busulfan. The apoptosis of granulosa cells (GCs) incubated with exosomes extracted from ovarian tissues of control and POI groups was analyzed by flow cytometry. Then, high-throughput sequencing was performed to detect the difference of miRNAs profile in ovarian tissue-derived exosomes between the control and POI mice. The effect of differential miRNA on the apoptosis of CTX-induced ovarian GCs was analyzed by flow cytometry. The results showed that POI mouse model was successfully established. Exosomes extracted from ovarian of normal and POI group have different effects on apoptosis of GCs induced by CTX. miRNA-seq found that exosomal miR-122-5p in POI group increased significantly. miR-122-5p as the dominant miRNA targeting BCL9 was significantly upregulated in ovarian tissues of chemotherapy-induced POI group. Exosomes derived from the ovaries in the control group and miR-122-5p inhibitor group attenuated the apoptosis of primary cultured ovarian GCs. In conclusion, exosomal miR-122-5p promoted the apoptosis of ovarian GCs by targeting BCL9, suggested that miR-122-5p may function as a potential target to restore ovarian function.
... 2,12,[15][16][17][18][19][20] The rapid progress in the field mandates vigilance for new developments since both MSC products and their treatment indications have greatly diversified during the past decade. 2,12,[18][19][20][21][22][23][24][25][26][27][28][29][30] Recognizing the diversification of MSC products and the increased use of MSCs in humans, guidelines are being established by several regulatory authorities, such as the US Federal Drug Administration (FDA) and European Medicines Agency (EMA), 7,20,24,[30][31][32][33][34][35][36] as well as international societies, such as ISCT and International Society for Stem Cell Research (ISSCR). 13,37,38 These guidelines aim to ensure the quality and safety of these novel advanced therapy medicinal products (ATMPs). ...
Article
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The number of mesenchymal stromal/stem cell (MSC) therapeutics and types of clinical applications have greatly diversified during the past decade, including rapid growth of poorly regulated “Stem Cell Clinics” offering diverse “Unproven Stem Cell Interventions.” This product diversification necessitates a critical evaluation of the reliance on the 2006 MSC minimal criteria to not only define MSC identity but characterize MSC suitability for intravascular administration. While high-quality MSC therapeutics have been safely administered intravascularly in well-controlled clinical trials, repeated case reports of mild-to-more-severe adverse events have been reported. These are most commonly related to thromboembolic complications upon infusion of highly procoagulant tissue factor (TF/CD142)-expressing MSC products. As TF/CD142 expression varies widely depending on the source and manufacturing process of the MSC product, additional clinical cell product characterization and guidelines are needed to ensure the safe use of MSC products. To minimize risk to patients receiving MSC therapy, we here propose to supplement the minimal criteria used for characterization of MSCs, to include criteria that assess the suitability of MSC products for intravascular use. If cell products are intended for intravascular delivery, which is true for half of all clinical applications involving MSCs, the effects of MSC on coagulation and hemocompatibility should be assessed and expression of TF/CD142 should be included as a phenotypic safety marker. This adjunct criterion will ensure both the identity of the MSCs as well as the safety of the MSCs has been vetted prior to intravascular delivery of MSC products.
... Notwithstanding the developing experimental and clinical application of MSCs in regenerative medicine [94][95][96], clinical MSC-based therapeutic approaches have not been efficiently organized as low engraftment and viability of cells restrict the therapeutic efficiency of MSC transplantation. So that several MSC immunotherapy trials on phase III are incapable of reaching the primary clinical endpoints considering the low efficiency of engrafted cells [6,97]. Despite comprehensive investigation of therapeutic applications, the efficacy of MSCs still confronts formidable questions. ...
Article
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Mesenchymal Stem cells (MSCs) are a population of non-hematopoietic and self-renewing cells characterized by the potential to differentiate into different cell subtypes. MSCs have interesting features which have attracted a lot of attention in various clinical investigations. Some basic features of MSCs are including the weak immunogenicity (absence of MHC-II and costimulatory ligands accompanied by the low expression of MHC-I) and the potential of plasticity and multi-organ homing via expressing related surface molecules. MSCs by immunomodulatory effects could also ameliorate several immune-pathological conditions like graft-versus-host diseases (GVHD). The efficacy and potency of MSCs are the main objections of MSCs therapeutic applications. It suggested that improving the MSC immunosuppressive characteristic via genetic engineering to produce therapeutic molecules consider as one of the best options for this purpose. In this review, we explain the functions, immunologic properties and clinical applications of MSCs to discuss the beneficial application of genetically modified MSCs in GVHD.
... Several previous studies have shown that MSC transplantation can promote recovery from liver injury [6,7]. However, there are still certain obstacles that restrict the clinical efficacy of MSCs [8]. ...
Article
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Background Mesenchymal stem cell (MSC) transplantation is emerging as a promising cell therapeutic strategy in acute liver failure (ALF) clinical research. The potency of MSCs to migrate and engraft into targeted lesions could largely determine their clinical efficacy, in which chemokine/receptor axes play a crucial role. Unfortunately, the downregulation of chemokine receptors expression after in vitro expansion results in a poor homing capacity of MSCs. Methods By evaluating the chemokine expression profile in the liver of ALF patients and ALF mice, we found that CCL2 expression was highly upregulated in damaged livers, while the corresponding receptor, CCR2, was lacking in cultured MSCs. Thus, we genetically modified MSCs to overexpress CCR2 and investigated the targeted homing capacity and treatment efficacy of MSC CCR2 compared to those of the MSC vector control. Results In vivo and ex vivo near-infrared fluorescence imaging showed that MSC CCR2 rapidly migrated and localized to injured livers in remarkably greater numbers following systemic infusion, and these cells were retained in liver lesions for a longer time than MSC vector . Furthermore, MSC CCR2 exhibited significantly enhanced efficacy in the treatment of ALF in mice, which was indicated by a dramatically improved survival rate, the alleviation of liver injury with reduced inflammatory infiltration and hepatic apoptosis, and the promotion of liver regeneration. Conclusions Altogether, these results indicate that CCR2 overexpression enhances the targeted migration of MSCs to damaged livers, improves their treatment effect, and may provide a novel strategy for improving the efficacy of cell therapy for ALF.
... A limitation is the very low number of cells in the tissue of origin that forced to use in vitro expansion protocols to achieve feasible amounts of cells for infusion or transplantation. However, there is increasing evidence that in vitro expansion induces drastic changes in phenotype and biological properties of MSCs, with significant possible implications for therapy [5][6][7]. Research aimed to shed light on MSC origin failed to identify an unambiguous unique in vivo progenitor, whereas the hypothesis that MSCs could possibly arise from different precursors is gaining consensus [8][9][10][11]. ...
... A limitation is the very low number of cells in the tissue of origin that forced to use in vitro expansion protocols to achieve feasible amounts of cells for infusion or transplantation. However, there is increasing evidence that in vitro expansion induces drastic changes in phenotype and biological properties of MSCs, with significant possible implications for therapy [5][6][7]. Research aimed to shed light on MSC origin failed to identify an unambiguous unique in vivo progenitor, whereas the hypothesis that MSCs could possibly arise from different precursors is gaining consensus [8][9][10][11]. ...
... We anticipate a bright future for MSC-based therapies in patients with SSc through the accurate selection of optimally matched MSC donors for each disease profile [149]. The therapeutic efficacy of employing MSCs is currently rather low [443]. Preconditioned or engineered MSCs with improved survival, paracrine signalling, migration and therapeutic effects may be more suitable for the treatment of refractory SSc. ...
Article
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Systemic sclerosis (SSc) is an intractable autoimmune disease with unmet medical needs. Conventional immunosuppressive therapies have modest efficacy and obvious side effects. Targeted therapies with small molecules and antibodies remain under investigation in small pilot studies. The major breakthrough was the development of autologous haematopoietic stem cell transplantation (AHSCT) to treat refractory SSc with rapidly progressive internal organ involvement. However, AHSCT is contraindicated in patients with advanced visceral involvement. Mesenchymal stem cells (MSCs) which are characterized by immunosuppressive, antifibrotic and proangiogenic capabilities may be a promising alternative option for the treatment of SSc. Multiple preclinical and clinical studies on the use of MSCs to treat SSc are underway. However, there are several unresolved limitations and safety concerns of MSC transplantation, such as immune rejections and risks of tumour formation, respectively. Since the major therapeutic potential of MSCs has been ascribed to their paracrine signalling, the use of MSC-derived extracellular vesicles (EVs)/secretomes/exosomes as a “cell-free” therapy might be an alternative option to circumvent the limitations of MSC-based therapies. In the present review, we overview the current knowledge regarding the therapeutic efficacy of MSCs in SSc, focusing on progresses reported in preclinical and clinical studies using MSCs, as well as challenges and future directions of MSC transplantation as a treatment option for patients with SSc.
... Although originally isolated from bone marrow, MSCs have been found to reside in virtually all post-natal human tissues and organs [21,22]. MSCs are easily attainable, can be isolated from various tissues, and show promise therapeutically due to their differentiation capacity and ability to activate endogenous progenitor cells through paracrine signalling [23]. Furthermore, the ability of MSCs to migrate to sites of inflammation throughout the body, including the central nervous system (CNS), could facilitate viral dissemination if MSCs are indeed an additional HIV-1 reservoir [22,24]. ...
Article
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The introduction of antiretroviral therapy (ART) and highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV)-1 into a chronic, well-managed disease. However, these therapies do not eliminate all infected cells from the body despite suppressing viral load. Viral rebound is largely due to the presence of cellular reservoirs which support long-term persistence of HIV-1. A thorough understanding of the HIV-1 reservoir will facilitate the development of new strategies leading to its detection, reduction, and elimination, ultimately leading to curative therapies for HIV-1. Although immune cells derived from lymphoid and myeloid progenitors have been thoroughly studied as HIV-1 reservoirs, few studies have examined whether mesenchymal stromal/stem cells (MSCs) can assume this function. In this review, we evaluate published studies which have assessed whether MSCs contribute to the HIV-1 reservoir. MSCs have been found to express the receptors and co-receptors required for HIV-1 entry, albeit at levels of expression and receptor localisation that vary considerably between studies. Exposure to HIV-1 and HIV-1 proteins alters MSC properties in vitro, including their proliferation capacity and differentiation potential. However, in vitro and in vivo experiments investigating whether MSCs can become infected with and harbour latent integrated proviral DNA are lacking. In conclusion, MSCs appear to have the potential to contribute to the HIV-1 reservoir. However, further studies are needed using techniques such as those used to prove that cluster of differentiation (CD)4 ⁺ T cells constitute an HIV-1 reservoir before a reservoir function can definitively be ascribed to MSCs. Graphical abstract MSCs may contribute to HIV-1 persistence in vivo in the vasculature, adipose tissue, and bone marrow by being a reservoir for latent HIV-1. To harbour latent HIV-1, MSCs must express HIV-1 entry markers, and show evidence of productive or latent HIV-1 infection. The effect of HIV-1 or HIV-1 proteins on MSC properties may also be indicative of HIV-1 infection.
... Mesenchymal stem/stromal cells (MSCs) are heterogeneous multipotent cells with evident therapeutic potential for treating intractable disorders [1][2][3][4][5][6][7] . In addition to their therapeutic properties, MSCs can act as vehicles for cell-based gene therapies 8,9 . ...
Article
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C-X-C chemokine receptor type 4 (CXCR4), initially recognized as a co-receptor for HIV, contributes to several disorders, including the WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome. CXCR4 binds to its ligand SDF-1 to make an axis involved in the homing property of stem cells. This study aimed to employ WHIM syndrome pathogenesis as an inspirational approach to reinforce cell therapies. Wild type and WHIM-type variants of the CXCR4 gene were chemically synthesized and cloned in the pCDH-513B-1 lentiviral vector. Molecular cloning of the synthetic genes was confirmed by DNA sequencing, and expression of both types of CXCR4 at the protein level was confirmed by western blotting in HEK293T cells. Human adipose-derived mesenchymal stem cells (Ad-MSCs) were isolated, characterized, and subjected to lentiviral transduction with Wild type and WHIM-type variants of CXCR4. The presence of copGFP-positive MSCs confirmed the high efficiency of transduction. The migration ability of both groups of transduced cells was then assessed by transwell migration assay in the presence or absence of a CXCR4-blocking agent. Our qRT-PCR results showed overexpression of CXCR4 at mRNA level in both groups of transduced MSCs, and expression of WHIM-type CXCR4 was significantly higher than Wild type CXCR4 ( P<0.05). Our results indicated that the migration of genetically modified MSCs expressing WHIM-type CXCR4 had significantly enhanced towards SDF1 in comparison with Wild type CXCR4 ( P<0.05), while it was reduced after treatment with CXCR4 antagonist. These data suggest that overexpression of WHIM-type CXCR4 could lead to enhanced and sustained expression of CXCR4 on human MSCs, which would increase their homing capability; hence it might be an appropriate strategy to improve the efficiency of cell-based therapies.
... Second, the infusion of a large number of MSCs may cause thrombosis (137,138), headache, and fever (139). Third, the low survival time and efficiency of MSCs in vivo may limit their therapeutic efficiency (140). Fourth, although several studies have attempted to improve MSC therapy with techniques such as transfecting CDR1 (141) and hepatocyte nuclear factor-4 alpha (HNF-4a) to regulate the biological characteristics of MSCs directly (142), no practical strategy is applicable in clinical practice and increases the risk of MSC application. ...
Article
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Diabetes mellitus and the associated complications are metabolic diseases with high morbidity that result in poor quality of health and life. The lack of diagnostic methods for early detection results in patients losing the best treatment opportunity. Oral hypoglycemics and exogenous insulin replenishment are currently the most common therapeutic strategies, which only yield temporary glycemic control rather than curing the disease and its complications. Exosomes are nanoparticles containing bioactive molecules reflecting individual physiological status, regulating metabolism, and repairing damaged tissues. They function as biomarkers of diabetes mellitus and diabetic complications. Considering that exosomes are bioactive molecules, can be obtained from body fluid, and have cell-type specificity, in this review, we highlight the multifold effects of exosomes in the pathology and therapy of diabetes mellitus and diabetic complications.
... Taking into consideration that the therapeutic effect is caused mainly by soluble factors, it seems rational to replace MSCs in regenerative medicine and inflammatory diseases therapies with the factors they produce [25][26][27]. Single agents with potential wound healing effects have been also tested. ...
Article
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For twenty-five years, attempts have been made to use MSCs in the treatment of various diseases due to their regenerative and immunomodulatory properties. However, the results are not satisfactory. Assuming that MSCs can be replaced in some therapies by the active factors they produce, the immortalized MSCs line was established from human adipose tissue (HATMSC1) to produce conditioned media and test its regenerative potential in vitro in terms of possible clinical application. The production of biologically active factors by primary MSCs was lower compared to the HATMSC1 cell line and several factors were produced only by the cell line. It has been shown that an HATMSC1-conditioned medium increases the proliferation of various cell types, augments the adhesion of cells and improves endothelial cell function. It was found that hypoxia during culture resulted in an augmentation in the pro-angiogenic factors production, such as VEGF, IL-8, Angiogenin and MCP-1. The immunomodulatory factors caused an increase in the production of GM-CSF, IL-5, IL-6, MCP-1, RANTES and IL-8. These data suggest that these factors, produced under different culture conditions, could be used for different medical conditions, such as in regenerative medicine, when an increased concentration of pro-angiogenic factors may be beneficial, or in inflammatory diseases with conditioned media with a high concentration of immunomodulatory factors.
... Intravenous is the most widely used method in preclinical studies and it can promote recovery significantly; however, in most researches, intravenous in animal models could cause lung, liver, and spleen embolisms like pulmonary embolisms and diffuse alveolar hemorrhages, which happened in patients as demonstrated by two cases with venous clots at the proximal end of the puncture site (Oeller et al., 2018). Apart from that, many studies showed that the majority of cells were trapped in the peripheral organs such as the lung, spleen, and liver because of blood circulation and only a few of them got to the infarction area and differentiated into neuronal cells and glial cells (Ankrum and Karp, 2010). On the contrary, other people found that distribution in other organs is rare (Moon et al., 2019). ...
Article
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Stroke is the third most common disease all over the world, which is regarded as a hotspot in medical research because of its high mortality and morbidity. Stroke, especially ischemic stroke, causes severe neural cell death, and no effective therapy is currently available for neuroregeneration after stroke. Although many therapies have been shown to be effective in preclinical studies of ischemic stroke, almost none of them passed clinical trials, and the reasons for most failures have not been well identified. In this review, we focus on several novel methods, such as traditional Chinese medicine, stem cell therapy, and exosomes that have not been used for ischemic stroke till recent decades. We summarize the proposed basic mechanisms underlying these therapies and related clinical results, discussing advantages and current limitations for each therapy emphatically. Based on the limitations such as side effects, narrow therapeutic window, and less accumulation at the injury region, structure transformation and drug combination are subsequently applied, providing a deep understanding to develop effective treatment strategies for ischemic stroke in the near future.
... Cells were applied as suspensions injected intradermally/subcutaneously or intravenously, topically by cell spraying, or seeded on electrospun or biological scaffolds, including the amniotic membrane. Cell therapy implemented by administering cells to the bloodstream may lead to the accumulation of injected cells in other organs such as the lungs (Ankrum and Karp, 2010). ...
Article
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Knowledge of the beneficial effects of perinatal derivatives (PnD) in wound healing goes back to the early 1900s when the human fetal amniotic membrane served as a biological dressing to treat burns and skin ulcerations. Since the twenty-first century, isolated cells from perinatal tissues and their secretomes have gained increasing scientific interest, as they can be obtained non-invasively, have anti-inflammatory, anti-cancer, and anti-fibrotic characteristics, and are immunologically tolerated in vivo. Many studies that apply PnD in pre-clinical cutaneous wound healing models show large variations in the choice of the animal species (e.g., large animals, rodents), the choice of diabetic or non-diabetic animals, the type of injury (full-thickness wounds, burns, radiation-induced wounds, skin flaps), the source and type of PnD (placenta, umbilical cord, fetal membranes, cells, secretomes, tissue extracts), the method of administration (topical application, intradermal/ subcutaneous injection, intravenous or intraperitoneal injection, subcutaneous implantation), and the type of delivery systems (e.g., hydrogels, synthetic or natural biomaterials as carriers for transplanted cells, extracts or secretomes). This review provides a comprehensive and integrative overview of the application of PnD in wound healing to assess its efficacy in preclinical animal models. We highlight the advantages and limitations of the most commonly used animal models and evaluate the impact of the type of PnD, the route of administration, and the dose of cells/secretome application in correlation with the wound healing outcome. This review is a collaborative effort from the COST SPRINT Action (CA17116), which broadly aims at approaching consensus for different aspects of PnD research, such as providing inputs for future standards for the preclinical application of PnD in wound healing.
... Recently, clinical research on adipose tissue and the heterogeneous populations within its SVF has accelerated, and several scientific investigations are ongoing to examine the use of ASCs and SVF cells in regenerative medicine and tissue engineering [52]. To date, it is challenging to define a common isolation method and characterization profile of ASC found in the adipose tissue due to the discrepancy among researchers' protocols and the small number of reports. ...
Preprint
Background: Developing an efficient and standardized method to isolate and characterize adipose-derived stem cells (ASCs) from the stromal vascular fraction (SVF) of the adipose tissue for clinical application represents one of the major challenges in cell therapy and tissue engineering. Methods: In this study, we proposed an innovative, non-enzymatic protocol to collect clinically useful ASCs within freshly isolated SVF from adipose tissue by centrifugation of the infranatant portion of lipoaspirate and to determine the characteristic cytofluorimetric pattern, prior to in vitro culture. Results: The SVF yielded a mean of 73,32 \pm\ 10,89% cell viability evaluated with CALCEINA-FITC, i.e. cell-permeant dye. The ASCs were positive for PC7-labeled mAb anti-CD34 and negative for both PE-labeled mAb anti-CD31 and APC-labeled mAb anti-CD45. The frequency of ASCs estimated according to the panel of cell surface markers used was 51,06%\ \pm 5,26% versus the unstained ASCs subpopulation that was 0,74%\pm0,84% (P<0.0001). The ASCs events/\muL were 1602,13/\muL \pm 731,87/\muL. Conclusion: Our findings suggested that ASCs found in freshly isolated adipose SVF obtained by centrifugation of lipoaspirate can be immunophenotypically identified with a basic panel of cell surface markers. These findings aimed to provide standardization and contribute to reducing the inconsistency on reported cell surface antigens of ASC derived from the existing literature.
... Recently, hMSC-DP have been applied to regenerate orofacial tissues and treat systemic diseases in pre-clinical and clinical settings [11,[14][15][16][17][18]. It is well-known that the quality and potency of MSCs are critical to ensure their therapeutic effects [19]. However, the minimum criteria for MSCs formulated by ISCT may not provide enough guidance to evaluate the quality and potency of hMSC-DP [8]. ...
Article
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Background Human mesenchymal stem cells from dental pulp (hMSC-DP), including dental pulp stem cells from permanent teeth and exfoliated deciduous teeth, possess unique MSC characteristics such as expression of specific surface molecules and a high proliferation rate. Since hMSC-DP have been applied in numerous clinical studies, it is necessary to establish criteria to evaluate their potency for cell-based therapies. Methods We compared stem cell properties of hMSC-DP at passages 5, 10 and 20 under serum (SE) and serum-free (SF) culture conditions. Cell morphology, proliferation capacity, chromosomal stability, surface phenotypic profiles, differentiation and immunoregulation ability were evaluated. In addition, we assessed surface molecule that regulates hMSC-DP proliferation and immunomodulation. Results hMSC-DP exhibited a decrease in proliferation rate and differentiation potential, as well as a reduced expression of CD146 when cultured under continuous passage conditions. SF culture conditions failed to alter surface marker expression, chromosome stability or proliferation rate when compared to SE culture. SF-cultured hMSC-DP were able to differentiate into osteogenic, adipogenic and neural cells, and displayed the capacity to regulate immune responses. Notably, the expression level of CD146 showed a positive correlation with proliferation, differentiation, and immunomodulation, suggesting that CD146 can serve as a surface molecule to evaluate the potency of hMSC-DP. Mechanistically, we found that CD146 regulates proliferation and immunomodulation of hMSC-DP through the ERK/p-ERK pathway. Conclusion This study indicates that SF-cultured hMSC-DP are appropriate for producing clinical-grade cells. CD146 is a functional surface molecule to assess the potency of hMSC-DP.
Chapter
Allograft tissues in orthobiologics can be classified as cellular (containing viable nucleated cells) or acellular (no viable cells). The focus of cellular allografts is to capitalize on the reparative role of the mesenchymal stem cell (MSC) to manage the body’s innate healing abilities. Acellular allografts work through their growth factor and cytokine composition in an effort to activate the body's healing response. Allografts have many advantages over their autologous counterparts: no pain or procedural complications within the harvesting process, improved time efficiency to transplant, the opportunity to culture-expand and obtain standardized quantities of cellular components, and they may be used on patients with medical comorbidities that would preclude them from using their own autologous tissues. This chapter focuses on the basic science and clinical applications of culture-expanded MSCs from various sources, amniotic tissue, cord blood, and exosome allografts, as well as demineralized bone matrix. Currently, clinical evidence for the use of these grafts needs significant development and these applications must be ensured to fall in line with regulatory guidelines.
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Chapter
Stroke is the second leading cause of disability and death in the world. Therefore, there is an urgent need to develop treatment strategies for stroke. Stem cell therapeutics appears to be a promising alternative to approved thrombolytic or thrombectomy approaches. Stem cells can repopulate into various cell types in an ischemic brain by stimulating endogenous stem cell pools or following exogenous transplantation. However, the efficacy of stem cell therapy is contingent upon the stem cells’ ability to home and engraft in the injury site over an extended period. The purpose of this chapter is to discuss various strategies, such as preconditioning of stem cells (use of hypoxia, chemokine approaches, etc.), selecting the optimal time window, and route of delivery used to enhance stem cell homing ability in stroke.KeywordsStrokeStem cellsHomingHypoxiaChemokines
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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.
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INTRODUCTION Hyperglycemia reversal and preservation/restoration of β-cells function in diabetic infarction remains as an attractive and challengeable therapeutic target. Mesenchymal stem cells (MSCs) are multipotent cells with a strong immunoregulatory potential that have emerged as a possible cell-based therapy for a variety of immunological diseases. The objective of this study was to examine the dose-dependent efcacy of intravenous administration of human umbilical cord blood derived MSCs (UCB-MSCs) in chemically induced rats with diabetic infraction. METHODS Wister rats (weight: 200-250g, males) received intraperitoneal streptozotocin injection followed by isoproterenol to develop diabetes infarction condition. After model development animals received intravenous single or double dose of human 6 UCB-MSCs (5 X 10 cells per animal at each dose) and followed up to 30 days post-administration. Pancreatic tissue histology, blood glucose and insulin levels were measured, and proportion of animal survival was calculated using Kaplan-Meier curve analysis. RESULTS Double dose of MSCs infusion resulted in reorganization of islet cells and partial restoration of β-cells at day 30. Comparatively faster restoration of glucose and insulin normalization was observed for two MSCs doses compared to single dose. Highest proportion of animal survival was observed (>85%) for double doses of MSCs infusion compared to single dose (>70%) at day 30. CONCLUSION Two consecutive intravenous doses of human UCB-MSCs can improve structural and functional decits of pancreatic tissues and maintain blood glucose and insulin levels in diabetic infarcted rats up to 30 days. However, identication of long-term effects entails longer follow-up periods, and larger sample sizes with other investigations.
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Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have potential therapeutic value, because these have high self-renewal ability, are capable of multipotent differentiation, and have low immunogenicity. Furthermore, MSCs have the potential to differentiate into hepatocytes, and the therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. Moreover, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis, and enhance liver functionality. This article is protected by copyright. All rights reserved.
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The mechanism(s) underlying cardiac reparative effects of bone marrow-derived mesenchymal stem cells (MSC) remain highly controversial. Here we tested the hypothesis that MSCs regenerate chronically infarcted myocardium through mechanisms comprising long-term engraftment and trilineage differentiation. Twelve weeks after myocardial infarction, female swine received catheter-based transendocardial injections of either placebo (n = 4) or male allogeneic MSCs (200 million; n = 6). Animals underwent serial cardiac magnetic resonance imaging, and in vivo cell fate was determined by co-localization of Y-chromosome (Y(pos)) cells with markers of cardiac, vascular muscle, and endothelial lineages. MSCs engrafted in infarct and border zones and differentiated into cardiomyocytes as ascertained by co-localization with GATA-4, Nkx2.5, and alpha-sarcomeric actin. In addition, Y(pos) MSCs exhibited vascular smooth muscle and endothelial cell differentiation, contributing to large and small vessel formation. Infarct size was reduced from 19.3 +/- 1.7% to 13.9 +/- 2.0% (P < 0.001), and ejection fraction (EF) increased from 35.0 +/- 1.7% to 41.3 +/- 2.7% (P < 0.05) in MSC but not placebo pigs over 12 weeks. This was accompanied by increases in regional contractility and myocardial blood flow (MBF), particularly in the infarct border zone. Importantly, MSC engraftment correlated with functional recovery in contractility (R = 0.85, P < 0.05) and MBF (R = 0.76, P < 0.01). Together these findings demonstrate long-term MSC survival, engraftment, and trilineage differentiation following transplantation into chronically scarred myocardium. MSCs are an adult stem cell with the capacity for cardiomyogenesis and vasculogenesis which contribute, at least in part, to their ability to repair chronically scarred myocardium.
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Research on stem cells has progressed at a rapid pace and, as might be anticipated, the results have generated several controversies, a few myths and a change in a major paradigm. Some of these issues will be reviewed in this study with special emphasis on how they can be applied to the adult stem/progenitor cells from bone marrow, referred to as MSCs.
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Stem cells reside in a specialized, regulatory environment termed the niche that dictates how they generate, maintain and repair tissues. We have previously documented that transplanted haematopoietic stem and progenitor cell populations localize to subdomains of bone-marrow microvessels where the chemokine CXCL12 is particularly abundant. Using a combination of high-resolution confocal microscopy and two-photon video imaging of individual haematopoietic cells in the calvarium bone marrow of living mice over time, we examine the relationship of haematopoietic stem and progenitor cells to blood vessels, osteoblasts and endosteal surface as they home and engraft in irradiated and c-Kit-receptor-deficient recipient mice. Osteoblasts were enmeshed in microvessels and relative positioning of stem/progenitor cells within this complex tissue was nonrandom and dynamic. Both cell autonomous and non-autonomous factors influenced primitive cell localization. Different haematopoietic cell subsets localized to distinct locations according to the stage of differentiation. When physiological challenges drove either engraftment or expansion, bone-marrow stem/progenitor cells assumed positions in close proximity to bone and osteoblasts. Our analysis permits observing in real time, at a single cell level, processes that previously have been studied only by their long-term outcome at the organismal level.
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A new era has begun in the treatment of ischemic disease and heart failure. With the discovery that stem cells from diverse organs and tissues, including bone marrow, adipose tissue, umbilical cord blood, and vessel wall, have the potential to improve cardiac function beyond that of conventional pharmacological therapy comes a new field of research aiming at understanding the precise mechanisms of stem cell-mediated cardiac repair. Not only will it be important to determine the most efficacious cell population for cardiac repair, but also whether overlapping, common mechanisms exist. Increasing evidence suggests that one mechanism of action by which cells provide tissue protection and repair may involve paracrine factors, including cytokines and growth factors, released from transplanted stem cells into the surrounding tissue. These paracrine factors have the potential to directly modify the healing process in the heart, including neovascularization, cardiac myocyte apoptosis, inflammation, fibrosis, contractility, bioenergetics, and endogenous repair.
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We screened for surface proteins expressed only by the early progenitor cells present in low-passage, low-density cultures of the adult stem/progenitor cells from bone marrow referred to as mesenchymal stem cells or multipotent stromal cells (MSCs). Six proteins were identified that were selectively expressed in the early progenitors: podocalyxin-like protein (PODXL), alpha6-integrin (CD49f), alpha4-integrin (CD49d), c-Met, CXCR4, and CX3CR1. All were previously shown to be involved in cell trafficking or tumor progression. Antibodies to CD49f and PODXL, a sialomucin in the CD34 family, were the most robust for FACScan assays. PODXL(hi)/CD49f(hi) MSCs were more clonogenic and differentiated more efficiently than PODXL(lo)/CD49f(lo) cells. Inhibition of expression of PODXL with RNA interference caused aggregation of the cells. Furthermore, PODXL(hi)/CD49f(hi) MSCs were less prone to produce lethal pulmonary emboli, and larger numbers were recovered in heart and kidney after intravenous infusion into mice with myocardial infarcts.
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Bone marrow-derived mesenchymal stem cells (MSCs) have the potential to differentiate along different mesenchymal lineages including those forming bone, cartilage, tendon, fat, muscle and marrow stroma that supports hematopoiesis. This differentiation potential makes MSCs candidates for cell-based therapeutic strategies for mesenchymal tissue injuries and for hematopoietic disorders by both local and systemic application. In the present study, rat marrow-derived MSCs were ex vivo culture-expanded, labeled with (111)In-oxine, and infused into syngeneic rats via intra-artery (i.a.), intravenous (i.v.) and intraperitoneal cavity (i.p.) infusions. In addition, for i.a. and i.v. infusions, a vasodilator, sodium nitroprusside, was administered prior to the cell infusion and examined for its effect on MSC circulation. The dynamic distribution of infused MSCs was monitored by real-time imaging using a gamma camera immediately after infusion and at 48 h postinfusion. After 48 h, radioactivity in excised organs, including liver, lungs, kidneys, spleen and long bones, was measured in a gamma well counter and expressed as a percentage of injected doses. After both i.a. and i.v. infusion, radioactivity associated with MSCs was detected primarily in the lungs and then secondarily in the liver and other organs. When sodium nitroprusside was used, more labeled MSCs cleared the lungs resulting in a larger proportion detected in the liver. Most importantly, the homing of labeled MSCs to the marrow of long bones was significantly increased by the pretreatment with vasodilator. These results indicate multiple homing sites for injected MSCs and that the distribution of MSCs can be influenced by administration of vasodilator.
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CD2(+) T lymphocytes obtained from either the donor of bone marrow stromal cells (BMSCs) or a third party were cultured in mixed lymphocyte reactions (MLRs) with either allogeneic dendritic cells (DCs) or peripheral blood lymphocytes (PBLs). When autologous or allogeneic BMSCs were added back to T cells stimulated by DCs or PBLs, a significant and dose-dependent reduction of T-cell proliferation, ranging from 60% +/- 5% to 98% +/- 1%, was evident. Similarly, addition of BMSCs to T cells stimulated by polyclonal activators resulted in a 65% +/- 5% (P =.0001) suppression of proliferation. BMSC- induced T-cell suppression was still evident when BMSCs were added in culture as late as 5 days after starting of MLRs. BMSC-inhibited T lymphocytes were not apoptotic and efficiently proliferated on restimulation. BMSCs significantly suppressed both CD4(+) and CD8(+) T cells (65% +/- 5%, [P =.0005] and 75% +/- 15% [P =.0005], respectively). Transwell experiments, in which cell-cell contact between BMSCs and effector cells was prevented, resulted in a significant inhibition of T-lymphocyte proliferation, suggesting that soluble factors were involved in this phenomenon. By using neutralizing monoclonal antibodies, transforming growth factor beta1 and hepatocyte growth factor were identified as the mediators of BMSC effects. In conclusion, our data demonstrate that (1) autologous or allogeneic BMSCs strongly suppress T-lymphocyte proliferation, (2) this phenomenon that is triggered by both cellular as well as nonspecific mitogenic stimuli has no immunologic restriction, and (3) T-cell inhibition is not due to induction of apoptosis and is likely due to the production of soluble factors.
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Recent studies describe beneficial effects of bone marrow-derived mesenchymal stem cell infusion in animal models as well as in patients. However, data on the homing abilities of primary and culture-expanded MSC are lacking. In order to systematically investigate MSC homing we compared the fate of both primary and cultured MSC in a syngeneic mouse model. Twenty-four hours after transplantation of uncultured EGFP-transgenic MSC into sublethally irradiated mice, as many as 55-65% of injected CFU-F were recovered from the BM and 3.5-7% from the spleen. In the subsequent 4 weeks these donor CFU-F expanded 100-fold, which resulted in a normalization of femoral and splenic CFU-F numbers. This highly efficient homing of primary CFU-F contrasted with the defective homing of MSC following culture. Following their infusion immortalized multipotent syngeneic stromal cells were undetectable in BM, spleen, lymph nodes or thymus. Remarkably, following transplantation of primary MSC that had been cultured for only 24 h the seeding fraction in the BM was reduced to 10%, while after transplantation of 48 h cultured primary MSC no CFU-F were detected in the lymphohematopoietic organs. These data suggest that in vitro propagation of BM-derived MSC dramatically decreases their homing to BM and spleen.
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Transplantation of adult bone marrow-derived mesenchymal stem cells has been proposed as a strategy for cardiac repair following myocardial damage. However, poor cell viability associated with transplantation has limited the reparative capacity of these cells in vivo. In this study, we genetically engineered rat mesenchymal stem cells using ex vivo retroviral transduction to overexpress the prosurvival gene Akt1 (encoding the Akt protein). Transplantation of 5 x 10(6) cells overexpressing Akt into the ischemic rat myocardium inhibited the process of cardiac remodeling by reducing intramyocardial inflammation, collagen deposition and cardiac myocyte hypertrophy, regenerated 80-90% of lost myocardial volume, and completely normalized systolic and diastolic cardiac function. These observed effects were dose (cell number) dependent. Mesenchymal stem cells transduced with Akt1 restored fourfold greater myocardial volume than equal numbers of cells transduced with the reporter gene lacZ. Thus, mesenchymal stem cells genetically enhanced with Akt1 can repair infarcted myocardium, prevent remodeling and nearly normalize cardiac performance.
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The organization of cellular niches is known to have a key role in regulating normal stem cell differentiation and regeneration, but relatively little is known about the architecture of microenvironments that support malignant metastasis. Using dynamic in vivo confocal imaging, here we show that murine bone marrow contains unique anatomic regions defined by specialized endothelium. This vasculature expresses the adhesion molecule E-selectin and the chemoattractant stromal-cell-derived factor 1 (SDF-1) in discrete, discontinuous areas that influence the homing of a variety of tumour cell lines. Disruption of the interactions between SDF-1 and its receptor CXCR4 inhibits the homing of Nalm-6 cells (an acute lymphoblastic leukaemia cell line) to these vessels. Further studies revealed that circulating leukaemic cells can engraft around these vessels, suggesting that this molecularly distinct vasculature demarcates a microenvironment for early metastatic tumour spread in bone marrow. Finally, purified haematopoietic stem/progenitor cells and lymphocytes also localize to the same microdomains, indicating that this vasculature might also function in benign states to demarcate specific portals for the entry of cells into the marrow space. Specialized vascular structures therefore appear to delineate a microenvironment with unique physiology that can be exploited by circulating malignant cells.
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Cell-based cardiac repair offers the promise of rebuilding the injured heart from its component parts. Work began with committed cells such as skeletal myoblasts, but recently the field has expanded to explore an array of cell types, including bone marrow cells, endothelial progenitors, mesenchymal stem cells, resident cardiac stem cells, and both mouse and human embryonic stem cells. A related strategy for cardiac repair involves cell mobilization with factors such as cytokines. Translation of cell-based approaches to the clinic has progressed rapidly, and clinical trials using autologous skeletal myoblasts and bone marrow cells are under way. Many challenges remain before the vision of healing an infarct by muscle regeneration can be realized. Future research is likely to focus on improving our ability to guide the differentiation of stem cells, control their survival and proliferation, identify factors that mediate their homing and modulate the heart's innate inflammatory and fibrotic responses.
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Mesenchymal stem cells (MSCs) are multipotent cells which can give rise to mesenchymal and non-mesenchymal tissues in vitro and in vivo. Whereas in vitro properties such as (trans)differentiation capabilities are well known, there is little information regarding natural distribution and biology in the living organism. To investigate the subject further, we generated long-term cultures of cells with mesenchymal stem cell characteristics from different organs and tissues from adult mice. These populations have morphology, immunophenotype and growth properties similar to bone marrow-derived MSCs. The differentiation potential was related to the tissue of origin. The results indicate that (1) cells with mesenchymal stem characteristics can be derived and propagated in vitro from different organs and tissues (brain, spleen, liver, kidney, lung, bone marrow, muscle, thymus, pancreas); (2) MSC long-term cultures can be generated from large blood vessels such as the aorta artery and the vena cava, as well as from small vessels such as those from kidney glomeruli; (3) MSCs are not detected in peripheral blood. Taken together, these results suggest that the distribution of MSCs throughout the post-natal organism is related to their existence in a perivascular niche. These findings have implications for understanding MSC biology, and for clinical and pharmacological purposes.
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TSG-6 is a multifunctional protein that is up-regulated in many pathological and physiological contexts, where it plays important roles in inflammation and tissue remodelling. For example, it is a potent inhibitor of neutrophil migration and can modulate the protease network through inhibition of plasmin. TSG-6 binds a wide range of GAGs (glycosaminoglycans) [i.e. HA (hyaluronan), chondroitin 4-sulphate, dermatan sulphate, heparin and heparan sulphate] as well as a variety of protein ligands, where these interactions can influence the activities of TSG-6. For example, through its association with HA, TSG-6 can mediate HA cross-linking via several different mechanisms, some of which promote leucocyte adhesion. Binding to heparin, however, enhances the ability of TSG-6 to potentiate the anti-plasmin activity of inter-alpha-inhibitor, which binds non-covalently to TSG-6 via its bikunin chain. Furthermore, although HA and heparin interact with distinct sites on the Link module, the binding of heparin can inhibit subsequent interaction with HA. In addition, the interactions of TSG-6 with HA, heparin and at least some of its protein ligands are sensitive to pH. Therefore it seems that in different tissue micro-environments (characterized, for example, by pH and GAG content), TSG-6 could be partitioned into functional pools with distinct activities.
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Molecular expression on the vascular endothelium is critical in regulating the interaction of circulating cells with the blood vessel wall. Leukocytes as well as circulating cancer cells gain entry into tissue by interacting with adhesion molecules on the endothelial cells (EC). Molecular targets on the EC are increasingly being explored for tissue-specific delivery of therapeutic and imaging agents. Here we use in vivo immunofluorescence microscopy to visualize the endothelial molecular expression in the vasculature of live animals. High-resolution images are obtained by optical sectioning through the intact skin using in vivo confocal and multiphoton microscopy after in situ labeling of EC surface markers with fluorescent antibodies. Other vascular beds such as the bone marrow and ocular blood vessels can be imaged with little or no tissue manipulation. Live imaging is particularly useful for following the dynamic expression of inducible molecules such as E-selectin during an inflammatory response.
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To explore the initial steps by which transplanted mesenchymal stem cells (MSCs) interact with the vessel wall in the course of extravasation, we studied binding of human MSCs to endothelial cells (ECs). In a parallel plate flow chamber, MSCs bound to human umbilical vein ECs (HUVECs) similar to peripheral-blood mononuclear cells (PBMCs) or CD34(+) hematopoietic progenitors at shear stresses of up to 2 dynes/cm(2). This involved rapid extension of podia, rolling, and subsequent firm adhesion that was increased when ECs were prestimulated with TNF-alpha. MSC binding was suppressed when ECs were pretreated with function-blocking anti-P-selectin antibody, and rolling of MSCs was induced on immobilized P-selectin, indicating that P-selectin was involved in this process. Preincubation of HUVECs with anti-VCAM-1 or of MSCs with anti-VLA-4 antibodies suppressed binding of MSCs to HUVECs but did not enhance inhibition by anti-P-selectin, indicating that both P-selectin and VCAM-1 are equally required for this process. Intravital microscopy demonstrated the capacity of MSCs to roll and adhere to postcapillary venules in vivo in a mouse model in a P-selectin-dependent manner. Thus, MSCs interact in a coordinated fashion with ECs under shear flow, engaging P-selectin and VCAM-1/VLA-4.
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Mesenchymal stem cells (MSCs) have been exploited as cellular vectors to treat a wide array of diseases but the mechanisms responsible for their therapeutic effect remain indeterminate. Previously, we reported that MSCs inhibit bleomycin (BLM)-induced inflammation and fibrosis within the lungs of mice. Interrogation of the MSC transcriptome identified interleukin 1 receptor antagonist (IL1RN) as a potential mediator of this effect. Fractionation studies indicated that MSCs are the principal source of IL1RN in murine bone marrow and that its expression is restricted to a unique subpopulation of cells. Moreover, MSC-conditioned media was shown to block proliferation of an IL-1α-dependent T cell line and inhibit production of TNF-α by activated macrophages in vitro. Studies conducted in mice revealed that MSC administration was more effective than recombinant IL1RN delivered via adenoviral infection or osmotic pumps in inhibiting BLM-induced increases in TNF-α, IL-1α, and IL1RN mRNA in lung, IL1RN protein in bronchoalveolar lavage (BAL) fluid, and trafficking of lymphocytes and neutrophils into the lung. Therefore, MSCs protect lung tissue from BLM-induced injury by blocking TNF-α and IL-1, two fundamental proinflammatory cytokines in lung. Identification of IL1RN-expressing human MSC subpopulations may provide a novel cellular vector for treating chronic inflammatory diseases in humans. • bleomycin • inflammation
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Nonobese diabetic/severe combined immune deficiency (NOD/SCID) mouse repopulating cells (SRC) have been proposed to represent a more primitive human stem cell subset than the cobblestone area-forming cell (CAFC) week (wk) 6 or the long-term culture-initiating cell (LTC-IC) wk 5 on the basis of their difference in frequency, phenotype, transfectibility, and multilineage outgrowth potential in immunodeficient recipients. We have assessed the percentage of various progenitor cell populations (colony-forming cell [CFC] and CAFC subsets) contained in unsorted NOD/SCID BM nucleated cells (nc), human umbilical cord blood (UCB) nc, bone marrow (BM) nc, peripheral blood stem cells (PBSC), and CD34+ selected UCB nc, seeding in the BM and spleen of NOD/SCID mice within 24 hours after transplantation. The seeding efficiency of NOD/SCID BM CAFC wk 5 was median (range) in the spleen 2.9% (0.7% to 4.0%) and in the total BM 8.7% (2.0% to 9.2%). For human unsorted UCB nc, BM nc, PBSC, and CD34+ UCB cells, the seeding efficiency for CAFC wk 6 in the BM of NOD/SCID mice was 4.4% (3.5% to 6.3%), 0.8% (0.3% to 1.7%), 5.3% (1.4% to 13.6%), and 4.4% (3.5% to 6.3%), respectively. Using flow cytometry, the percentage CD34+UCB cells retrieved from the BM of sublethally or supralethally irradiated NOD/SCID mice was 2.3 (1.4 to 2.8) and 2.5 (1.6 to 2.7), respectively. Because we did not observe any significant differences in the seeding efficiencies of the various stem cell subsets, it may be assumed that the SRC seeding efficiency in NOD/SCID mice is similarly low. Our data indicate that the seeding efficiency of a graft can be of great influence when assessing stem cell frequencies in in vivo repopulation assays.
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Mesenchymal stem cells (MSC) from adult bone marrow have the capacity to differentiate into several mesenchymal tissues and inhibit T-cell alloreactivity in vitro. Within the EBMT MSC expansion consortium we have used MSC to treat grades III-IV acute graft-versus-host disease (GvHD) in 40 patients. The MSC dose was median 1.0 (range 0.4–9) 10^6 cells/kg body weight of the recipient. No side-effects were seen after MSC infusions. Nineteen patients received one dose, 19 patients received two doses, two patients received three and five doses respectively. MSC donors were in five cases HLA-identical sibling donors, 19 haploidentical donors and 41 third-party HLA-mismatched donors. Among the 40 patients treated for severe acute GvHD, 21 had complete responses, eight showed improvement, eight patients did not respond, two had stable disease and one patient was not evaluated due to short follow-up. Twenty patients are alive between six weeks up to 3.5 years after transplantation. Nine of these patients have extensive chronic GvHD. One patient with ALL has recurrent leukaemia and one patient has denovo AML of recipient origin. We conclude that MSC have immunomodulatory and tissue repairing effects and should be further explored as treatment of severe acute GvHD in prospective randomized trials.
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Objective: To investigate the dynamic distribution of bone marrow-derived mesenchymal stem cells after infusion for a longer time and the influence of different infusion portals. Methods: Bone marrow-derived mesenchymal stem cells labeled with 3H-TdR were injected into 30 irradiated mdx mice via tail vein or intraperitoneal cavity, in a quantity of 4 × 106 per mice. The radioactivity concentration of blood, heart, liver, spleen, lung, kidney, muscle, brain and bone marrow were detected at 24-hour, 48-hour, 2-week, 1-month, 2-month, 4-month points after infusion and calculated by % ID/g with liquid scintillation counting. Results: (1) Radioactivity concentration of brain and bone marrow reached the highest level at 2-week time point after infusion via tail vein, but that of heart and muscle did at 4-month point. At early time, the stem cells mainly distributed in lung, liver and bone marrow, then at 2-month point the distribution in muscle and heart muscle was increased but still less than that in bone marrow. (2) The time for radioactivity concentration of blood, lung, kidney, spleen, brain to reach the peak was retarded via peritoneal cavity than that via tail vein. At early time, the concentration in lung, liver and bone marrow was similar to that via tail vein, the concentration of muscle was lower than that of the bone marrow at 2-month point. (3) Radioactivity concentration of heart, muscle, brain, bone marrow was much higher via tail vein compared to that via peritoneal cavity, showing a statistical significance (P < 0.01). Conclusions: Radioactivity concentration in muscle reaches the highest level at 4-month point after infusion and is influenced by different infusion portals. 3H-TdR should be an excellent tracer for observing the dynamic distribution of stem cells for a longer time.
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Multipotent mesenchymal stromal/stem cells (MSC) have shown potential clinical utility. However, previous assessments of MSC behavior in recipients have relied on visual detection in host tissue following sacrifice, failing to monitor in vivo MSC dispersion in a single animal and limiting the number of variables that can be observed concurrently. In this study, we used noninvasive, in vivo bioluminescent imaging to determine conditions under which MSC selectively engraft in sites of inflammation. MSC modified to express firefly luciferase (ffLuc-MSC) were injected into healthy mice or mice bearing inflammatory insults, and MSC localization was followed with bioluminescent imaging. The inflammatory insults investigated included cutaneous needle-stick and surgical incision wounds, as well as xenogeneic and syngeneic tumors. We also compared tumor models in which MSC were i.v. or i.p. delivered. Our results demonstrate that ffLuc-expressing human MSC (hMSC) systemically delivered to nontumor-bearing animals initially reside in the lungs, then egress to the liver and spleen, and decrease in signal over time. However, hMSC in wounded mice engraft and remain detectable only at injured sites. Similarly, in syngeneic and xenogeneic breast carcinoma-bearing mice, bioluminescent detection of systemically delivered MSC revealed persistent, specific colocalization with sites of tumor development. This pattern of tropism was also observed in an ovarian tumor model in which MSC were i.p. injected. In this study, we identified conditions under which MSC tropism and selective engraftment in sites of inflammation can be monitored by bioluminescent imaging over time. Importantly, these consistent findings were independent of tumor type, immunocompetence, and route of MSC delivery. STEM CELLS 2009;27:2614–2623
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Recently there has been a paradigm shift in what is considered to be the therapeutic promise of mesenchymal stem cells (MSCs) in diseases of vital organs. Originally, research focused on MSCs as a source of regenerative cells by differentiation of transplanted cells into lost cell types. It is now clear that trophic modulation of inflammation, cell death, fibrosis, and tissue repair are the main mechanisms of MSC therapy. Delivery of growth factors, cytokines, and other signaling molecules secreted by MSCs is often sufficient to obtain the therapeutic effects. In this article, we provide an overview of the current knowledge on trophic mechanisms of MSC therapy in disease models of vital organs. Important issues regarding the optimal delivery methods of MSC therapy are discussed and critical gaps in our knowledge hampering experimental progress and clinical implementation are identified.
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To address trafficking of transplanted marrow cells immediately after intravenous infusion, we examined the early fate of infused non-adherent, low-density donor bone marrow cells in a syngeneic mouse model. The presence of infused donor cells, marked with indium-111 oxine (111In), with the fluorescent dye PKH26, or by a detectable transgene marker, was evaluated at 3-48 h in a variety of tissues, including peripheral blood. All three cell-marking methods indicated a rapid (< 4 h) influx of cells into the bone marrow, liver, spleen, muscle and other tissues. Moreover, these tissues remained positive for the 48 h observation period. Interestingly, analysis of PKH26-positive cells in non-myeloablated animals demonstrated that approximately 17% of infused donor marrow cells localized to the marrow space within 15 h, whereas a smaller proportion of donor cells (approximately 1-2%) localized to the marrow in recipients preconditioned by irradiation. In an effort to enrich for cells that specifically home to the bone marrow, PKH26-labelled donor marrow cells were recovered from the first host and infused into a secondary recipient. Although this was a phenotypically undefined population of cells, no increase was observed in the relative fraction of PKH26-labelled cells returning or 'homing' to the marrow of the second recipient. Taken together, these data suggest both that marrow engraftment may be mediated by non-specific 'seeding' rather than a specific homing signal, and that efficient targeting of transplanted cells to the marrow is a complex multifaceted process.
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Quantum dots (QDs) are semiconductor nanocrystals, and recently they have been shown as effective probes for cell labeling. Due to their unique spectral, physical, and chemical properties, QDs can concurrently tag multiple intercellular and intracellular components of live cells for time ranging from seconds to months. Different color QDs can label different cell components that can be visualized with fluorescent microscopy or in vivo. Here, we provide a detailed protocol for labeling postnatal and differentiated stem/progenitor cells with bioconjugated quantum dots. For example, peptide CGGGRGD is immobilized on CdSe-ZnS QDs with free carboxyl groups. These bioconjugates label selected integrins on cell membrane of human mesenchymal stem cells (hMSCs). QD concentration and incubation time to effectively label hMSCs is optimized. We discovered that bioconjugated QDs effectively label hMSCs not only during population doubling, but also during multi-lineage differentiation into osteoblasts, chondrocytes, and adipocytes. Undifferentiated and differentiated stem cells labeled with bioconjugated QDs can be readily imaged by fluorescent microscopy. Thus, quantum dots represent an effective cell labeling probe and an alternative to organic dyes and fluorescent proteins for cell labeling and cell tracking.
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Our aim was to investigate the safety and efficacy of intravenous allogeneic human mesenchymal stem cells (hMSCs) in patients with myocardial infarction (MI). Bone marrow-derived hMSCs may ameliorate consequences of MI, and have the advantages of preparation ease, allogeneic use due to immunoprivilege, capacity to home to injured tissue, and extensive pre-clinical support. We performed a double-blind, placebo-controlled, dose-ranging (0.5, 1.6, and 5 million cells/kg) safety trial of intravenous allogeneic hMSCs (Prochymal, Osiris Therapeutics, Inc., Baltimore, Maryland) in reperfused MI patients (n=53). The primary end point was incidence of treatment-emergent adverse events within 6 months. Ejection fraction and left ventricular volumes determined by echocardiography and magnetic resonance imaging were exploratory efficacy end points. Adverse event rates were similar between the hMSC-treated (5.3 per patient) and placebo-treated (7.0 per patient) groups, and renal, hepatic, and hematologic laboratory indexes were not different. Ambulatory electrocardiogram monitoring demonstrated reduced ventricular tachycardia episodes (p=0.025), and pulmonary function testing demonstrated improved forced expiratory volume in 1 s (p=0.003) in the hMSC-treated patients. Global symptom score in all patients (p=0.027) and ejection fraction in the important subset of anterior MI patients were both significantly better in hMSCs versus placebo subjects. In the cardiac magnetic resonance imaging substudy, hMSC treatment, but not placebo, increased left ventricular ejection fraction and led to reverse remodeling. Intravenous allogeneic hMSCs are safe in patients after acute MI. This trial provides pivotal safety and provisional efficacy data for an allogeneic bone marrow-derived stem cell in post-infarction patients. (Safety Study of Adult Mesenchymal Stem Cells [MSC] to Treat Acute Myocardial Infarction; NCT00114452).
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Mesenchymal stem cell (MSC)-based therapeutics are showing significant benefit in multiple clinical trials conducted by both academic and commercial organizations, but obstacles remain for their large-scale commercial implementation. Recent studies have attempted to optimize MSC-based therapeutics by either enhancing their potency or increasing their delivery to target tissues. Overexpression of trophic factors or in vitro exposure to potency-enhancing factors are two approaches that are demonstrating success in preclinical animal models. Delivery enhancement strategies involving tissue-specific cytokine pathways or binding sites are also showing promise. Each of these strategies has its own set of distinct advantages and disadvantages when viewed with a mindset of ultimate commercialization and clinical utility.
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Quantitative assays for human DNA and mRNA were used to examine the paradox that intravenously (i.v.) infused human multipotent stromal cells (hMSCs) can enhance tissue repair without significant engraftment. After 2 x 10(6) hMSCs were i.v. infused into mice, most of the cells were trapped as emboli in lung. The cells in lung disappeared with a half-life of about 24 hr, but <1000 cells appeared in six other tissues. The hMSCs in lung upregulated expression of multiple genes, with a large increase in the anti-inflammatory protein TSG-6. After myocardial infarction, i.v. hMSCs, but not hMSCs transduced with TSG-6 siRNA, decreased inflammatory responses, reduced infarct size, and improved cardiac function. I.v. administration of recombinant TSG-6 also reduced inflammatory responses and reduced infarct size. The results suggest that improvements in animal models and patients after i.v. infusions of MSCs are at least in part explained by activation of MSCs to secrete TSG-6.
Article
The objective of the study was to track the distribution and differentiation of mesenchymal stem cells (MSCs) in tumor-bearing mice. The 4T1 murine breast cancer cells were labeled with renilla luciferase-monomeric red fluorescence protein (rLuc-mRFP) reporter gene. The MSCs labeled with firefly luciferase-enhanced green fluorescence protein (fLuc-eGFP) reporter gene (MSCs-R) were isolated from L2G85 transgenic mice that constitutively express fLuc-eGFP reporter gene. To study the tumor tropism of MSCs, we established both subcutaneous and lung metastasis models. In lung metastasis tumor mice, we injected MSCs-R intravenously either on the same day or 4 days after 4T1 tumor cell injection. In subcutaneous tumor mice, we injected MSCs-R intravenously 7 days after subcutaneous 4T1 tumor inoculation. The tumor growth was monitored by rLuc bioluminescence imaging (BLI). The fate of MSCs-R was monitored by fLuc BLI. The localization of MSCs-R in tumors was examined histologically. The osteogenic and adipogenic differentiation of MSCs-R was investigated by alizarin red S and oil red O staining, respectively. The mechanism of the dissimilar differentiation potential of MSCs-R under different tumor microenvironments was investigated. We found that the 4T1 cells were successfully labeled with rLuc-mRFP. The MSCs-R isolated from L2G85 transgenic mice constitutively express fLuc-eGFP reporter gene. When injected intravenously, MSCs-R survived, proliferated, and differentiated in tumor sites but not elsewhere. The localization of GFP(+) MSCs-R in tumor lesions was confirmed ex vivo. In conclusion, the MSCs-R can selectively localize, survive, and proliferate in both subcutaneous tumor and lung metastasis as evidenced by noninvasive bioluminescence imaging and ex vivo validation. The MSCs-R migrated to lung tumor differentiated into osteoblasts, whereas the MSCs-R targeting subcutaneous tumor differentiated into adipocytes.