Mesenchymal stem versus stromal cells: International Society for Cell & Gene Therapy (ISCT®) Mesenchymal Stromal Cell committee position statement on nomenclature

Potential therapeutic effects and nano-based delivery systems of mesenchymal stem cells and their isolated exosomes to alleviate acute respiratory distress syndrome caused by COVID-19

The severe respiratory effects of the coronavirus disease 2019 (COVID-19) pandemic have necessitated the immediate development of novel treatments. The majority of COVID-19-related fatalities are due to acute respiratory distress syndrome (ARDS). Consequently, this virus causes massive and aberrant inflammatory conditions, which must be promptly managed. Severe respiratory disorders, notably ARDS and acute lung injury (ALI), may be treated safely and effectively using cell-based treatments, mostly employing mesenchymal stem cells (MSCs). Since the high potential of these cells was identified, a great deal of research has been conducted on their use in regenerative medicine and complementary medicine. Multiple investigations have demonstrated that MSCs and their products, especially exosomes, inhibit inflammation. Exosomes serve a critical function in intercellular communication by transporting molecular cargo from donor cells to receiver cells. MSCs and their derived exosomes (MSCs/MSC-exosomes) may improve lung permeability, microbial and alveolar fluid clearance, and epithelial and endothelial repair, according to recent studies. This review focuses on COVID-19-related ARDS clinical studies involving MSCs/MSC-exosomes. We also investigated the utilization of Nano-delivery strategies for MSCs/MSC-exosomes and anti-inflammatory agents to enhance COVID-19 treatment.

Application of mesenchymal stem/stromal cells in periodontal regeneration: Opportunities and challenges

Guided tissue regeneration (GTR) has been widely used in the periodontal treatment of intrabony and furcation defects for nearly four decades. The treatment outcomes have shown effectiveness in reducing pocket depth, improving attachment gain and bone filling in periodontal tissue. Although applying GTR could reconstruct the periodontal tissue, the surgical indications are relatively narrow, and some complications and race ethic problems bring new challenges. Therefore, it is challenging to achieve a consensus concerning the clinical benefits of GTR. With the appearance of stem cell-based regenerative medicine, mesenchymal stem/stromal cells (MSCs) have been considered a promising cell resource for periodontal regeneration. In this review, we highlight preclinical and clinical periodontal regeneration using MSCs derived from distinct origins, including non-odontogenic and odontogenic tissues and induced pluripotent stem cells, and discuss the transplantation procedures, therapeutic mechanisms, and concerns to evaluate the effectiveness of MSCs.

International Society for Cell and Gene Therapy Clinical Translation Committee recommendations on mesenchymal stromal cells in graft-versus-host disease: easy manufacturing is faced with standardizing and commercialization challenges

Mesenchymal stromal cells (MSCs) have been used in multiple clinical trials for steroid-refractory moderate-severe (grade II-IV) acute graft-versus-host disease (aGVHD) across the world over the last two decades. Despite very promising results in a variety of trials, it failed to get widespread approval by regulatory agencies such as the U.S. Food and Drug Administration and the European Medicines Agency. What lessons can we learn from this for future studies on MSCs and other cell therapy products? Broad heterogeneity among published trials using MSCs in aGVHD was likely the core problem. We propose a standardized approach in regards to donor-related factors, MSCs-related characteristics, as well as clinical trial design, to limit heterogeneity in trials for aGVHD and to fulfill the requirements of regulatory agencies. This approach may be expanded beyond MSCs to other Cell and Gene therapy products and trials in other diseases.

Compact bone mesenchymal stem cells-derived paracrine mediators for cell-free therapy in sepsis

Sepsis, a life-threatening condition resulting in multiple organ dysfunction, is characterized by a dysregulated immune response to infection. Current treatment options are limited, leading to unsatisfactory outcomes for septic patients. Here, we present a series of studies utilizing compact bone mesenchymal stem cells (CB-MSCs) and their derived paracrine mediators, especially exosome (CB-MSCs-Exo), to treat mice with cecal ligation and puncture-induced sepsis. Our results demonstrate that CB-MSCs treatment significantly improves the survival rate of septic mice by mitigating excessive inflammatory response and attenuating sepsis-induced organ injuries. Furthermore, CB-MSCs-conditioned medium, CB-MSCs secretome (CB-MSCs-Sec), and CB-MSCs-Exo exhibit potent anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated murine macrophage (RAW264.7). Intriguingly, intravenous administration of CB-MSCs-Exo confers superior protection against inflammation and organ damage in septic mice compared to CB-MSCs in certain aspects. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS) shotgun proteomic analysis, we identify a range of characterized proteins derived from the paracrine activity of CB-MSCs, involved in critical biological processes such as immunomodulation and apoptosis. Our findings highlight that the paracrine products of CB-MSCs could serve as a promising cell-free therapeutic agent for sepsis.

Evaluation of enzymatic protocols to optimize efficiency of bovine adipose tissue-derived mesenchymal stromal cell isolation

Sustainable food provision for a continuously growing human population is one of the major challenges for the next decades. Cultured meat represents one of the alternatives which is currently extensively explored. Yet, the most appropriate cell type, capable of long-term proliferation and myogenic differentiation, remains to be identified. Bovine mesenchymal stromal cells (MSCs) are considered as a promising cell source. Within the context of cultured meat production, it is mandatory to maximize cell yield per tissue source. Although many enzymatic methods to isolate MSCs from adipose tissue (AT) have been described, cell yield has never been compared. In this study, we evaluate 32 isolation conditions including four enzyme mixtures (Collagenase type I, Collagenase type I + Trypsin, LiberaseTM and Collagenase type IV) at varying concentrations and incubation times, regarding their efficiency to isolate MSCs from bovine subcutaneous AT. The highest cell yield in combination with a low population doubling time was obtained using LiberaseTM at a concentration of 0.1% for 3 h. MSC identity of the cells was confirmed by tri-lineage differentiation potential and cell surface marker expression. Subsequently, isolated cells were myogenically differentiated using 5-aza-2'-deoxycytidine and galectin-1. mRNA levels of the myogenic regulatory factors (MRF) myogenic factor 5 (MYF5), myogenic differentiation 1 (MYOD1), MYF6, and myogenin (MYOG) were increased, while less paired box 3 (PAX3) mRNA expression was observed when compared to undifferentiated MSCs. The presence of desmin (DES), tropomyosin (TM), and myosin heavy chain (MyHC) in myogenically differentiated bovine AT-MSCs was confirmed using immunofluorescence stainings. When considering MSCs from bovine AT as potential cell source to produce cultured meat, it is recommended to use 0.1% LiberaseTM for 3 h to ensure a high cell yield.

Heterogeneity in Dental Tissue-Derived MSCs Revealed by Single-Cell RNA-seq

Mesenchymal stromal cells (MSCs) are multipotent, progenitor cells that reside in tissues across the human body, including the periodontal ligament (PDL) and gingiva. They are a promising therapeutic tool for various degenerative and inflammatory diseases. However, different heterogeneity levels caused by tissue-to-tissue and donor-to-donor variability, and even intercellular differences within a given MSCs population, restrict their therapeutic potential. There are considerable efforts to decipher these heterogeneity levels using different "omics" approaches, including single-cell transcriptomics. Previous studies applied this approach to compare MSCs isolated from various tissues of different individuals, but distinguishing between donor-to-donor and tissue-to-tissue variability is still challenging. In this study, MSCs were isolated from the PDL and gingiva of 5 periodontally healthy individuals and cultured in vitro. A total of 3,844 transcriptomes were generated using single-cell mRNA sequencing. Clustering across the 2 different tissues per donor identified PDL- and gingiva-specific and tissue-spanning MSCs subpopulations with unique upregulated gene sets. Gene/pathway enrichment and protein-protein interaction (PPI) network analysis revealed differences restricted to several cellular processes between tissue-specific subpopulations, indicating a limited tissue-of-origin variability in MSCs. Gene expression, pathway enrichment, and PPI network analysis across all donors' PDL- or gingiva-specific subpopulations showed significant but limited donor-to-donor differences. In conclusion, this study demonstrates tissue- and donor-specific variabilities in the transcriptome level of PDL- and gingiva-derived MSCs, which seem restricted to specific cellular processes. Identifying tissue-specific and tissue-spanning subpopulations highlights the intercellular differences in dental tissue-derived MSCs. It could be reasonable to control MSCs at a single-cell level to ensure their properties before transplantation.

1,25-dihydroxyvitamin-D3 distinctly impacts the paracrine and cell-to-cell contact interactions between hPDL-MSCs and CD4+ T lymphocytes

Introduction

Human periodontal ligament-derived mesenchymal stromal cells (hPDL-MSCs) possess a strong ability to modulate the immune response, executed via cytokine-boosted paracrine and direct cell-to-cell contact mechanisms. This reciprocal interaction between immune cells and hPDL-MSCs is influenced by 1,25-dihydroxyvitamin-D3 (1,25(OH)2D3). In this study, the participation of different immunomodulatory mechanisms on the hPDL-MSCs-based effects of 1,25(OH)2D3 on CD4+ T lymphocytes will be elucidated using different co-culture models with various cytokine milieus.

Material and methods

hPDL-MSCs and CD4+ T lymphocytes were co-cultured indirectly and directly with inserts (paracrine interaction only) or directly without inserts (paracrine and direct cell-to-cell contact interaction). They were stimulated with TNF-α or IL-1β in the absence/presence of 1,25(OH)2D3. After five days of co-cultivation, the CD4+ T lymphocyte proliferation, viability, and cytokine secretion were analyzed. Additionally, the gene expression of soluble and membrane-bound immunomediators was determined in hPDL-MSCs.

Results

In the indirect and direct co-culture model with inserts, 1,25(OH)2D3 decreased CD4+ T lymphocyte proliferation and viability. The direct co-culture model without inserts caused the opposite effect. 1,25(OH)2D3 mainly decreased the CD4+ T lymphocyte-associated secretion of cytokines via hPDL-MSCs. The degree of these inhibitions varied between the different co-culture setups. 1,25(OH)2D3 predominantly decreased the expression of the soluble and membrane-bound immunomediators in hPDL-MSCs to a different extent, depending on the co-culture models. The degree of all these effects depended on the absence and presence of exogenous TNF-α and IL-1β.

Conclusion

These data assume that 1,25(OH)2D3 differently affects CD4+ T lymphocytes via the paracrine and direct cell-to-cell contact mechanisms of hPDL-MSCs, showing anti- or pro-inflammatory effects depending on the co-culture model type. The local cytokine microenvironment seems to be involved in fine-tuning these effects. Future studies should consider this double-edged observation by executing different co-culture models in parallel.

Enhanced anti-tumor efficacy of S3I-201 in breast cancer mouse model through Wharton jelly- exosome

OBJECTIVE

Exosomes, membrane-enveloped vesicles found in various cell types, including Wharton's jelly mesenchymal stem cells, play a crucial role in intercellular communication and regulation. Their use as a cell-free nanotechnology and drug delivery system has attracted attention. Triple-negative breast cancer (TNBC) is a major global health problem and is characterized by a high mortality rate. This study investigates the potential of Wharton's Jelly mesenchymal stem cell-derived exosomes (WJ-Exo) as carriers of S3I-201 and their effects on STAT3 expression in breast cancer cell lines, and evaluates whether these exosomes can enhance the anti-tumor effect of S3I-201.

METHODS

The filtered WJ-Exos were analyzed by Transmission Electron Microscopy (TEM), Scanning electron microscopy (SEM), Dynamic Light Scattering (DLS), flow cytometry, and Western blotting. These exosomes were then used for loading with S3I-201, resulting in the nano-formulation WJ-Exo(S3I-201). The effect of WJ-Exo(S3I-201) on 4T1 cancer cells was investigated in vitro using MTT assay, flow cytometry, wound healing assay, Western blotting and Quantitative Real-Time Polymerase chain reaction (qPCR) analysis. Finally, the therapeutic efficacy of the nano-formulation was investigated in vivo using a tumor-bearing mouse model.

RESULTS

In vitro experiments showed that co-incubation of 4T1 cells with the nano-formulation resulted in a significant reduction in p-STAT3 levels, induction of apoptosis, modulation of Bcl-2, Bax and caspase-3 protein and gene expression, and inhibition of migration. In vivo, treatment of tumor-bearing mice with WJ-Exo(S3I-201) showed a strong antitumor effect that exceeded the efficacy observed in the S3I-201 group.

CONCLUSION

Our results demonstrate that WJ-Exo is an effective carrier for targeting S3I-201 to tumor cells and enhances the therapeutic efficacy of S3I-201 in tumor-bearing mice.

Synergistic Enhancement of Photodynamic Cancer Therapy with Mesenchymal Stem Cells and Theranostic Nanoparticles

Nanoparticles engineered to combat cancer and other life-threatening diseases may significantly improve patient outcomes. However, inefficient nanoparticle delivery to tumors limits their use and necessitates the development of complex delivery approaches. Here, we examine this issue by harnessing the tumor-homing abilities of human mesenchymal stem cells (MSCs) to deliver a decoupled theranostic complex of rare earth-doped nanoparticles (dNPs) and photosensitizer chlorin e6 (Ce6) to tumors. We show that both bone-marrow- and skin-derived MSCs can transport the dNP-Ce6 complex inside tumor spheroids, which is challenging to accomplish by passive delivery alone. MSCs deliver the dNP-Ce6 complex across the tumor spheroid, facilitating more effective photodynamic damage and tumor destruction than passively accumulated dNP-Ce6. The dNP-Ce6 complex also provides the built-in ability to monitor the MSC migration without causing undesired phototoxicity, which is essential for maximal and side-effect-free delivery of nanoparticles. Our results demonstrate how MSCs can be used as delivery vehicles for the transportation of the dNP-Ce6 complex, addressing the limitations of passive nanoparticle delivery and providing light-based theranostics.

Regulatory cell therapy for kidney transplantation and autoimmune kidney diseases

Regulatory cell therapies, including regulatory T cells and mesenchymal stromal cells, have shown promise in early clinical trials for reducing immunosuppression burden in transplantation. While regulatory cell therapies may also offer potential for treating autoimmune kidney diseases, data remains sparse, limited mainly to preclinical studies. This review synthesises current literature on the application of regulatory cell therapies in these fields, highlighting the safety and efficacy shown in existing clinical trials. We discuss the need for further clinical validation, optimisation of clinical and immune monitoring protocols, and the challenges of manufacturing and quality control under Good Manufacturing Practice conditions, particularly for investigator-led trials. Additionally, we explore the potential for expanding clinical indications and the unique challenges posed in paediatric applications. Future directions include scaling up production, refining protocols to ensure consistent quality across manufacturing sites, and extending applications to other immune-mediated diseases.

Single-Cell RNA Sequencing Reveals Repair Features of Human Umbilical Cord Mesenchymal Stromal Cells

Rationale: The chronic lung disease bronchopulmonary dysplasia (BPD) is the most severe complication of extreme prematurity. BPD results in impaired lung alveolar and vascular development and long-term respiratory morbidity, for which only supportive therapies exist. Umbilical cord-derived mesenchymal stromal cells (UC-MSCs) improve lung structure and function in experimental BPD. Results of clinical trials with MSCs for many disorders do not yet match the promising preclinical studies. A lack of specific criteria to define functionally distinct MSCs persists. Objectives: To determine and correlate single-cell UC-MSC transcriptomic profiles with therapeutic potential. Methods: UC-MSCs from five term donors and human neonatal dermal fibroblasts (HNDFs; control cells of mesenchymal origin) transcriptomes were investigated using single-cell RNA sequencing (scRNA-seq) analysis. The lung-protective effect of UC-MSCs with a distinct transcriptome and control HNDFs was tested in vivo in hyperoxia-induced neonatal lung injury in rats. Measurements and Main Results: UC-MSCs showed limited transcriptomic heterogeneity but were different from HNDFs. Gene Ontology enrichment analysis revealed distinct (progenitor-like and fibroblast-like) UC-MSC subpopulations. Only treatment with progenitor-like UC-MSCs improved lung function and structure and attenuated pulmonary hypertension in hyperoxia-exposed rat pups. Moreover, scRNA-seq identified major histocompatibility complex class I as a molecular marker of nontherapeutic cells and associated with decreased lung retention. Conclusions: UC-MSCs with a progenitor-like transcriptome, but not with a fibroblast-like transcriptome, provide lung protection in experimental BPD. High expression of major histocompatibility complex class I is associated with reduced therapeutic benefit. scRNA-seq may be useful to identify subsets of MSCs with superior repair capacity for clinical application.

Extracellular vesicles for the treatment of ulcerative colitis: A systematic review and meta-analysis of animal studies

Background

Extracellular vesicles (EVs) are being considered as a potential therapeutic option for ulcerative colitis (UC), and numerous preclinical studies have been conducted on the use of EVs for UC.

Methods

A systematic review was conducted to compare the therapeutic effects of mammalian EVs and placebo on UC in animal models, along with a meta-analysis comparing naïve (unmodified) EVs and placebo. The search was performed in four databases (PubMed, Web of Science, Scopus, and EMBASE) up to September 13th, 2023. The primary outcomes included disease activity index (DAI), colonic mucosal damage index (CMDI), and adverse effects (PROSPERO ID: CRD42023458039).

Results

A total of 69 studies were included based on pre-determined criteria, involving 1271 animals. Of these studies, 51 measured DAI scores, with 98 % reporting that EVs could reduce DAI scores. Additionally, 5 studies reported CMDI and all showed that EVs could significantly reduce CMDI. However, only 3 studies assessed adverse effects and none reported any significant adverse effects. The meta-analysis of these studies (40 studies involving 1065 animals) revealed that naïve EVs could significantly decrease the DAI score (SMD = -3.00; 95 % CI: -3.52 to -2.48) and CMDI (SMD = -2.10; 95 % CI: -2.85 to -1.35).

Conclusion

The results indicate that mammalian EVs have demonstrated therapeutic benefits in animal models of UC; however, the safety profile of EVs remains inadequate which highlights the need for further research on safety outcomes.

Quality Assessment of Long-Term Cryopreserved Human Bone-Derived Marrow Mesenchymal Stromal Cell Samples: Experience from the Texas Heart Institute Biorepository and Biospecimen Profiling Core

In biomedical research, biorepositories are pivotal resources that safeguard and supply clinical samples for scientific investigators. Proper long-term cryopreservation conditions are essential to maintain biospecimen quality. In this study, we analyzed the efficacy of sample cryopreservation at the Texas Heart Institute Biorepository and Biospecimen Profiling Core (THI-BRC). Our assessments included a thorough review of internal processes, quality reports, and both internal and external audit outcomes. We examined the integrity of human bone marrow-derived multipotent mesenchymal stromal cells (BM-MSCs) that were cryopreserved for over 5 years. These samples originated from randomly selected clinical trial participants or commercially sourced cell lines. Parameters such as cell viability, DNA and RNA integrity, population doubling time, sterility, and BM-MSC-specific attributes such as surface antigen expression and differentiation potential were studied. BM-MSC samples cryopreserved for ∼6 months served as our control. Our results demonstrated that the 5-year cryopreserved samples maintained their integrity compared with the shorter-term stored control samples. Moreover, THI-BRC has met accreditation agency standards and has not received any repeated deficiencies over 7 years. Collectively, our findings affirm that THI-BRC's biospecimen storage protocols align with accepted standards as confirmed by the quality assessment of long-term stored clinical samples.

Bone Marrow and Peripheral Blood Mononuclear Cell Phenotype Changes after Cultivation and Autologous Infusion in Patients with Primary Biliary Cholangitis

Background

Primary biliary cholangitis (PBC) is a condition affecting the liver and immune system. In this study, the impact of autologous bone marrow-derived mononuclear cell (BM-MNC) transplantation on PBC patients was investigated.

Methods

Sixteen eligible PBC patients participated at the National Scientific Medical Center in Astana, Kazakhstan, between 2017 and 2022, and BM-MNCs were harvested from their anterior iliac crest. After isolating and cultivating the BM-MNCs, they were infused back into the patient's peripheral veins. Changes in BM-MNC and peripheral blood mononuclear cell (PB-MNC) phenotypes were assessed before and after a 24-hour cultivation period and 72 hours post-transplantation. We monitored liver function parameters over 6-month intervals and conducted flow cytometry analysis to assess CD markers on BM-MNCs before and after cultivation and PB-MNCs before and after transplantation. Statistical analysis included the Friedman test for liver parameters and the Wilcoxon signed-rank test for BM-MNC and PB-MNC comparisons.

Results

Our findings revealed significant reductions in liver function tests after multiple transplantations. Flow cytometry analysis before and after a 24-hour culture and autologous BM-MNC infusion revealed the expansion of specific cell populations, with significant increases in CD3+, CD4+, CD16+, CD20+, CD25+, CD34+, CD105+, CD73+, СD117+, and CD34+populations, while CD4+25+, CD34+105+, and CD4+FOXP3+ populations decreased. Interestingly, a contradictory finding was observed with a decrease in bone marrow CD34+105+ cell lines (P=0.03) alongside an increase in peripheral CD34+105+ population (P=0.03).

Conclusion

In summary, our study shows that BM-MNC transplantation in PBC patients leads to changes in immune cell populations and liver function. These findings suggest potential therapeutic applications of BM-MNC transplantation in managing PBC and offer insights into the dynamics of immune cells associated with this treatment approach.

Differentiation, Metabolism, and Cardioprotective Secretory Functions of Human Cardiac Stromal Cells from Ischemic and Endocarditis Patients

This study investigates the characteristics of cardiac mesenchymal stem cell-like cells (CMSCLCs) isolated from the right atrial appendage of human donors with ischemia and a young patient with endocarditis (NE-CMSCLCs). Typical CMSCLCs from ischemic heart patients were derived from coronary artery bypass grafting procedures and compared against bone marrow mesenchymal stromal cells (BM-MSCs). NE-CMSCLCs had a normal immunophenotype, but exhibited enhanced osteogenic differentiation potential, rapid proliferation, reduced senescence, reduced glycolysis, and lower reactive oxygen species generation after oxidative stress compared with typical ischemic CMSCLCs. These differences suggest a unique functional status of NE-CMSCLCs, influenced by the donor health condition. Despite large variances in their paracrine secretome, NE-CMSCLCs retained therapeutic potential, as indicated by their ability to protect hypoxia/reoxygenation-injured human cardiomyocytes, albeit less effectively than typical CMSCLCs. This research describes a unique cell phenotype and underscores the importance of donor health status in the therapeutic efficacy of autologous cardiac cell therapy.

Mesenchymal Stem Cell-Derived Exosomes as a Treatment Option for Osteoarthritis

Osteoarthritis (OA) is a leading cause of pain and disability worldwide in elderly people. There is a critical need to develop novel therapeutic strategies that can effectively manage pain and disability to improve the quality of life for older people. Mesenchymal stem cells (MSCs) have emerged as a promising cell-based therapy for age-related disorders due to their multilineage differentiation and strong paracrine effects. Notably, MSC-derived exosomes (MSC-Exos) have gained significant attention because they can recapitulate MSCs into therapeutic benefits without causing any associated risks compared with direct cell transplantation. These exosomes help in the transport of bioactive molecules such as proteins, lipids, and nucleic acids, which can influence various cellular processes related to tissue repair, regeneration, and immune regulation. In this review, we have provided an overview of MSC-Exos as a considerable treatment option for osteoarthritis. This review will go over the underlying mechanisms by which MSC-Exos may alleviate the pathological hallmarks of OA, such as cartilage degradation, synovial inflammation, and subchondral bone changes. Furthermore, we have summarized the current preclinical evidence and highlighted promising results from in vitro and in vivo studies, as well as progress in clinical trials using MSC-Exos to treat OA.

Adipose-derived mesenchymal stromal cells in clinical trials: Insights from single-cell studies

Mesenchymal Stromal Cells (MSCs) offer tremendous potential for the treatment of various diseases and their healing properties have been explored in hundreds of clinical trials. These trails primarily focus on immunological and neurological disorders, as well as regenerative medicine. Adipose tissue is a rich source of mesenchymal stromal cells and methods to obtain and culture adipose-derived MSCs (AD-MSCs) have been well established. Promising results from pre-clinical testing of AD-MSCs activity prompted clinical trials that further led to the approval of AD-MSCs for the treatment of complex perianal fistulas in Crohn's disease and subcutaneous tissue defects. However, AD-MSC heterogeneity along with various manufacturing protocols or different strategies to boost their activity create the need for standardized quality control procedures and safety assessment of the intended cell product. High-resolution transcriptomic methods have been recently gaining attention, as they deliver insight into gene expression profiles of individual cells, helping to deconstruct cellular hierarchy and differentiation trajectories, and to understand cell-cell interactions within tissues. This article presents a comprehensive overview of completed clinical trials evaluating the safety and efficacy of AD-MSC treatment, together with current single-cell studies of human AD-MSC. Furthermore, our work emphasizes the increasing significance of single-cell research in elucidating the mechanisms of cellular action and predicting their therapeutic effects.

Repeat administration of human umbilical cord mesenchymal stem cells improves left ventricular diastolic function in mice with heart failure with preserved ejection fraction

Currently, no therapy is proven to effectively improve heart failure with preserved ejection fraction (HFpEF). Although stem cell therapy has demonstrated promising results in treating ischemic heart disease, the effectiveness of treating HFpEF with human umbilical cord mesenchymal stem cells (hucMSCs) remains unclear. To answer this question, we administered hucMSCs intravenously (i.v.), either once or repetitively, in a mouse model of HFpEF induced by a high-fat diet and NG-nitroarginine methyl ester hydrochloride. hucMSC treatment improved left ventricular diastolic dysfunction, reduced heart weight and pulmonary edema, and attenuated cardiac modeling (inflammation, interstitial fibrosis, and hypertrophy) in HFpEF mice. Repeat hucMSC administration had better outcomes than a single injection. In vitro, hucMSC culture supernatants reduced maladaptive remodeling in neonatal-rat cardiomyocytes. Ribonucleic acid sequencing and protein level analysis of left ventricle (LV) tissues suggested that hucMSCs activated the protein kinase B (Akt)/forkhead box protein O1 (FoxO1) signaling pathway to treat HFpEF. Inhibition of this pathway reversed the efficacy of hucMSC treatment. In conclusion, these findings indicated that hucMSCs could be a viable therapeutic option for HFpEF.

A Closer Look into White Adipose Tissue Biology and the Molecular Regulation of Stem Cell Commitment and Differentiation

White adipose tissue (WAT) makes up about 20-25% of total body mass in healthy individuals and is crucial for regulating various metabolic processes, including energy metabolism, endocrine function, immunity, and reproduction. In adipose tissue research, "adipogenesis" is commonly used to refer to the process of adipocyte formation, spanning from stem cell commitment to the development of mature, functional adipocytes. Although, this term should encompass a wide range of processes beyond commitment and differentiation, to also include other stages of adipose tissue development such as hypertrophy, hyperplasia, angiogenesis, macrophage infiltration, polarization, etc.… collectively, referred to herein as the adipogenic cycle. The term "differentiation", conversely, should only be used to refer to the process by which committed stem cells progress through distinct phases of subsequent differentiation. Recognizing this distinction is essential for accurately interpreting research findings on the mechanisms and stages of adipose tissue development and function. In this review, we focus on the molecular regulation of white adipose tissue development, from commitment to terminal differentiation, and examine key functional aspects of WAT that are crucial for normal physiology and systemic metabolic homeostasis.

In Vitro Cell Surface Marker Expression on Mesenchymal Stem Cell Cultures does not Reflect Their Ex Vivo Phenotype

Cell surface marker expression is one of the criteria for defining human mesenchymal stem or stromal cells (MSC) in vitro. However, it is unclear if expression of markers including CD73 and CD90 reflects the in vivo origin of cultured cells. We evaluated expression of 15 putative MSC markers in primary cultured cells from periosteum and cartilage to determine whether expression of these markers reflects either the differentiation state of cultured cells or the self-renewal of in vivo populations. Cultured cells had universal and consistent expression of various putative stem cell markers including > 95% expression CD73, CD90 and PDPN in both periosteal and cartilage cultures. Altering the culture surface with extracellular matrix coatings had minimal effect on cell surface marker expression. Osteogenic differentiation led to loss of CD106 and CD146 expression, however CD73 and CD90 were retained in > 90% of cells. We sorted freshly isolated periosteal populations capable of CFU-F formation on the basis of CD90 expression in combination with CD34, CD73 and CD26. All primary cultures universally expressed CD73 and CD90 and lacked CD34, irrespective of the expression of these markers ex vivo indicating phenotypic convergence in vitro. We conclude that markers including CD73 and CD90 are acquired in vitro in most 'mesenchymal' cells capable of expansion. Overall, we demonstrate that in vitro expression of many cell surface markers in plastic-adherent cultures is unrelated to their expression prior to culture.

Vascular endothelial growth factor secretion and immunosuppression are distinct potency mechanisms of human bone marrow mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) are investigated as cellular therapeutics for inflammatory bowel diseases and associated perianal fistula, although consistent efficacy remains a concern. Determining host factors that modulate MSCs' potency including their secretion of angiogenic and wound-healing factors, immunosuppression, and anti-inflammatory properties are important determinants of their functionality. We investigated the mechanisms that regulate the secretion of angiogenic and wound-healing factors and immune suppression of human bone marrow MSCs. Secretory analysis of MSCs focusing on 18 angiogenic and wound-healing secretory molecules identified the most abundancy of vascular endothelial growth factor A (VEGF-A). MSC viability and secretion of other angiogenic factors are not dependent on VEGF-A secretion which exclude the autocrine role of VEGF-A on MSC's fitness. However, the combination of inflammatory cytokines IFNγ and TNFα reduces MSC's VEGF-A secretion. To identify the effect of intestinal microvasculature on MSCs' potency, coculture analysis was performed between human large intestine microvascular endothelial cells (HLMVECs) and human bone marrow-derived MSCs. HLMVECs do not attenuate MSCs' viability despite blocking their VEGF-A secretion. In addition, HLMVECs neither attenuate MSC's IFNγ mediated upregulation of immunosuppressive enzyme indoleamine 2,3-dioxygenase nor abrogate suppression of T-cell proliferation despite the attenuation of VEGF-A secretion. We found that HLMVECs express copious amounts of endothelial nitric oxide synthase and mechanistic analysis showed that pharmacological blocking reverses HLMVEC-mediated attenuation of MSC's VEGF-A secretion. Together these results suggest that secretion of VEGF-A and immunosuppression are separable functions of MSCs which are regulated by distinct mechanisms in the host.

Cause and consequence of heterogeneity in human mesenchymal stem cells: Challenges in clinical application

Human mesenchymal stem cells (hMSCs) are mesoderm-derived adult stem cells with self-proliferation capacity, pluripotent differentiation potency, and excellent histocompatibility. These advantages make hMSCs a promising tool in clinical application. However, the majority of clinical trials using hMSC therapy for diverse human diseases do not achieve expectations, despite the prospective pre-clinical outcomes in animal models. This is partly attributable to the intrinsic heterogeneity of hMSCs. In this review, the cause of heterogeneity in hMSCs is systematically discussed at multiple levels, including isolation methods, cultural conditions, donor-to-donor variation, tissue sources, intra-tissue subpopulations, etc. Additionally, the effect of hMSCs heterogeneity on the contrary role in tumor progression and immunomodulation is also discussed. The attempts to understand the cellular heterogeneity of hMSCs and its consequences are important in supporting and improving therapeutic strategies for hMSCs.

Challenges of therapeutic applications and regenerative capacities of urine based stem cells in oral, and maxillofacial reconstruction

Urine-derived stem cells (USCs) have gained the attention of researchers in the biomedical field in the past few years . Regarding the several varieties of cells that have been used for this purpose, USCs have demonstrated mesenchymal stem cell-like properties, such as differentiation and immunomodulation. Furthermore, they could be differentiated into several lineages. This is very interesting for regenerative techniques based on cell therapy. This review will embark on describing their separation, and profiling. We will specifically describe the USCs characteristics, in addition to their differentiation potential. Then, we will introduce and explore the primary uses of USCs. These involve thier utilization as a platform to produce stem cells, however, we shall concentrate on the utilization of USCs for therapeutic, and regenerative orofacial applications, providing an in-depth evaluation of this purpose. The final portion will address the limitations and challenges of their implementation in regenerative dentistry.

Mesenchymal stromal cells and their secretory products reduce the inflammatory crosstalk between islets and endothelial cells

PURPOSE

Preculturing isolated islets with Mesenchymal Stromal Cells (MSCs) improves their functional survival in vitro and subsequent transplantation outcomes in vivo. The MSC secretory product Annexin A1 (ANXA1) is a key modulator of MSC-mediated improvements in islet function. The current study aims to determine the influence of MSCs and defined MSC secretory products, including ANXA1, on the inflammatory crosstalk between isolated islets and Endothelial Cells (ECs), using in vitro models of the clinically-preferred intraportal islet transplantation niche.

METHODS

Islets were cultured alone, with MSCs, or with MSC secretory products and exposed to pro-inflammatory cytokines. Islet gene expression of C-C Motif Chemokine Ligand 2 (CCL2), C-X-C Motif Chemokine Ligand (CXCL)-10 (CXCL10) and CXCL1 were assessed by RT-qPCR. EC activation was induced with 100 U/ml TNF for 24 h. Islet-EC co-cultures were used to determine the influence of MSCs, or MSC secretory products on the inflammatory crosstalk between isolated islets and ECs. VCAM-1 and ICAM-1 expression were assessed at the mRNA and protein level in ECs, using RT-qPCR and immunofluorescence.

RESULTS

MSCs reduce pro-inflammatory cytokine-induced islet CCL2, CXCL10, and CXCL1 gene expression, which is partially mimicked by ANXA1. MSCs and ANXA1 have a similar capacity to reduce TNF-induced EC activation. Isolated islets exacerbate TNF-induced EC activation. Preculturing islets with MSCs reduces islet-exacerbated EC activation. ANXA1 reduces islet-exacerbated EC activation, when present during the islet preculture and islet-EC co-culture period.

CONCLUSION

MSC-derived secretory factors, including ANXA1, may be used in islet transplantation protocols to target donor islet and host EC inflammation at the intraportal niche.

The application potential of iMSCs and iMSC-EVs in diseases

The immune system, functioning as the body's "defense army", plays a role in surveillance, defense. Any disruptions in immune system can lead to the development of immune-related diseases. Extensive researches have demonstrated the crucial immunoregulatory role of mesenchymal stem cells (MSCs) in these diseases. Of particular interest is the ability to induce somatic cells under specific conditions, generating a new cell type with stem cell characteristics known as induced pluripotent stem cell (iPSC). The differentiation of iPSCs into MSCs, specifically induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs), hold promise as a potential solution to the challenges of MSCs, potentially serving as an alternative to traditional drug therapies. Moreover, the products of iMSCs, termed induced pluripotent stem cell-derived mesenchymal stem cell-derived extracellular vesicles (iMSC-EVs), may exhibit functions similar to iMSCs. With the biological advantages of EVs, they have become the focus of "cell-free therapy". Here, we provided a comprehensive summary of the biological impact of iMSCs on immune cells, explored the applications of iMSCs and iMSC-EVs in diseases, and briefly discussed the fundamental characteristics of EVs. Finally, we overviewed the current advantages and challenges associated with iMSCs and iMSC-EVs. It is our hope that this review related to iMSCs and iMSC-EVs will contribute to the development of new approaches for the treatment of diseases.

The issue of heterogeneity of MSC-based advanced therapy medicinal products-a review

Mesenchymal stromal stem cells (MSCs) possess a remarkable potential for numerous clinical applications due to their unique properties including self-renewal, immunomodulation, paracrine actions and multilineage differentiation. However, the translation of MSC-based Advanced Therapy Medicinal Products (ATMPs) into the clinic has frequently met with inconsistent outcomes. One of the suspected reasons for this issue is the inherent and extensive variability that exists among such ATMPs, which makes the interpretation of their clinical efficacy difficult to assess, as well as to compare the results of various studies. This variability stems from numerous reasons including differences in tissue sources, donor attributes, variances in manufacturing protocols, as well as modes of administration. MSCs can be isolated from various tissues including bone marrow, umbilical cord, adipose tissue and others, each with its unique phenotypic and functional characteristics. While MSCs from different sources do share common features, they also exhibit distinct gene expression profiles and functional properites. Donor-specific factors such as age, sex, body mass index, and underlying health conditions can influence MSC phenotype, morphology, differentiation potential and function. Moreover, variations in preparation of MSC products introduces additional heterogeneity as a result of cell culture media composition, presence or absence of added growth factors, use of different serum supplements and culturing techniques. Once MSC products are formulated, storage protocols play a pivotal role in its efficacy. Factors that affect cell viability include cell concentration, delivery solution and importantly, post-thawing protocols where applicable. Ensuing, differences in administration protocols can critically affect the distribution and functionallity of administered cells. As MSC-based therapies continue to advance through numerous clinical trials, implication of strategies to reduce product heterogeneity is imperative. Central to addressing these challenges is the need for precise prediction of clinical responses, which require well-defined MSC populations and harmonized assessment of their specific functions. By addressing these issues by meaningful approaches, such as, e.g., MSC pooling, the field can overcome barriers to advance towards more consistent and effective MSC-based therapies.

Mesenchymal Stem Cells in Myelodysplastic Syndromes and Leukaemia

Mesenchymal stem cells (MSCs) are one of the main residents in the bone marrow (BM) and have an essential role in the regulation of haematopoietic stem cell (HSC) differentiation and proliferation. Myelodysplastic syndromes (MDSs) are a group of myeloid disorders impacting haematopoietic stem and progenitor cells (HSCPs) that are characterised by BM failure, ineffective haematopoiesis, cytopenia, and a high risk of transformation through the expansion of MDS clones together with additional genetic defects. It has been indicated that MSCs play anti-tumorigenic roles such as in cell cycle arrest and pro-tumorigenic roles including the induction of metastasis in MDS and leukaemia. Growing evidence has shown that MSCs have impaired functions in MDS, such as decreased proliferation capacity, differentiation ability, haematopoiesis support, and immunomodulation function and increased inflammatory alterations within the BM through some intracellular pathways such as Notch and Wnt and extracellular modulators abnormally secreted by MSCs, including increased expression of inflammatory factors and decreased expression of haematopoietic factors, contributing to the development and progression of MDSs. Therefore, MSCs can be targeted for the treatment of MDSs and leukaemia. However, it remains unclear what drives MSCs to behave abnormally. In this review, dysregulations in MSCs and their contributions to myeloid haematological malignancies will be discussed.

Comparative single-cell transcriptional and proteomic atlas of clinical-grade injectable mesenchymal source tissues

Bone marrow aspirate concentrate (BMAC) and adipose-derived stromal vascular fraction (ADSVF) are the most marketed stem cell therapies to treat a variety of conditions in the general population and elite athletes. Both tissues have been used interchangeably clinically even though their detailed composition, heterogeneity, and mechanisms of action have neither been rigorously inventoried nor compared. This lack of information has prevented investigations into ideal dosages and has facilitated anecdata and misinformation. Here, we analyzed single-cell transcriptomes, proteomes, and flow cytometry profiles from paired clinical-grade BMAC and ADSVF. This comparative transcriptional atlas challenges the prevalent notion that there is one therapeutic cell type present in both tissues. We also provide data of surface markers that may enable isolation and investigation of cell (sub)populations. Furthermore, the proteome atlas highlights intertissue and interpatient heterogeneity of injected proteins with potentially regenerative or immunomodulatory capacities. An interactive webtool is available online.

Review: Livestock cell types with myogenic differentiation potential: Considerations for the development of cultured meat

With the current environmental impact of large-scale animal production and societal concerns about the welfare of farm animals, researchers are questioning whether we can cultivate animal cells for the purpose of food production. This review focuses on a pivotal aspect of the cellular agriculture domain: cells. We summarised information on the various cell types from farm animals currently used for the development of cultured meat, including mesenchymal stromal cells, myoblasts, and pluripotent stem cells. The review delves into the advantages and limitations of each cell type and considers factors like the selection of the appropriate cell source, as well as cell culture conditions that influence cell performance. As current research in cultured meat seeks to create muscle fibers to mimic the texture and nutritional profile of meat, we focused on the myogenic differentiation capacity of the cells. The most commonly used cell type for this purpose are myoblasts or satellite cells, but given their limited proliferation capacity, efforts are underway to formulate myogenic differentiation protocols for mesenchymal stromal cells and pluripotent stem cells. The multipotent character of the latter cell types might enable the creation of other tissues found in meat, such as adipose and connective tissues. This review can help guiding the selection of a cell type or culture conditions in the context of cultured meat development.

20 years of treating ischemic cardiomyopathy with mesenchymal stromal cells: a meta-analysis and systematic review

This meta-analysis and systematic review compiles comparative data from 2004 to 2024, investigating the safety and efficacy of mesenchymal stem/stromal cells (MSCs) derived from various tissues for the treatment of ischemic cardiomyopathy (ICM) and associated heart failure. In addition, this review highlights the limitations of these interventions and provides valuable insights for future therapeutic approaches. Relevant articles were retrieved from the PubMed® database using targeted keywords. Our inclusion criteria included clinical trials with patients over 18 years of age, case reports and pilot studies. Animal experiments, in vitro studies, correlational and longitudinal studies, and study designs and protocols were excluded. Forty-nine original articles resulted in follow-up reports of 45 trials. MSCs from bone marrow, umbilical cord and adipose tissue were moderately well tolerated. Of the 1408 participants who received MSCs, 33 trials (67.3%) reported the occurrence of death or serious adverse events. These events resulted in 80 deaths (52% of reported cases) following MSC administration. Importantly, 41.3% of these deaths (n = 33) were not considered to be related to the intervention itself, while 40% of these deaths had no reported cause. As the primary outcome, the mean increase in left ventricular ejection fraction (LVEF) from baseline was 5.75% (95% CI: 3.38% -8.11%, p < 0.0001, I2 = 90,9%) in the randomized controlled trials only (n = 24) within the treatment groups and 3.19% (95% CI: 1.63% to 4.75%, p < 0.0001, I2 = 74,17%) in the control groups after the intervention. When the above results were compared using the standardized mean difference (SDM), a significance in favor of the treatment group was also found (SDM = 0.41; 95% CI: 0.19-0.64, p < 0.001, I2 = 71%). Although improvements were also seen in the control groups, 33.3% (n = 15) of the studies showed no significant difference between the control and treatment groups. The 6-minute walking test (6MWT) and New York Heart Association (NYHA) class scores, used for assessing exercise tolerance and quality of life (QoL), respectively, further supported the improvements in the treatment group. These improvements were noted as 62.5% (n = 10) for the 6MWT and 54.5% (n = 12) for the NYHA class scores. According to the risk of bias analysis, 4 trials were of good quality (11.8%), 15 were of fair quality (44.1%), and 15 were of poor quality (44.1%). Major limitations of these studies included small sample size, diagnostic challenges/lack, uncertain cell dosage and potential bias in patient selection. Despite the ongoing debate surrounding cell administration for ICM, there are supporting signs of improved clinical and laboratory outcomes, as well as improved QoL in the MSC-treated groups. However, it is important to recognize the limitations of each study, highlighting the need for larger, controlled trials to validate these findings.

Mesenchymal stem cell secretome: A promising therapeutic strategy for erectile dysfunction?

Objective

The secretome, comprising bioactive chemicals released by mesenchymal stem cells (MSCs), holds therapeutic promise in regenerative medicine. This review aimed to explore the therapeutic potential of the MSC secretome in regenerative urology, particularly for treating erectile dysfunction (ED), and to provide an overview of preclinical and clinical research on MSCs in ED treatment and subsequently to highlight the rationales, mechanisms, preclinical investigations, and therapeutic potential of the MSC secretome in this context.

Methods

The review incorporated an analysis of preclinical and clinical research involving MSCs in the treatment of ED. Subsequently, it delved into the existing knowledge regarding the MSC secretome, exploring its therapeutic potential. The methods included a comprehensive examination of relevant literature to discern the processes underlying the therapeutic efficacy of the MSC secretome.

Results

Preclinical research indicated the effectiveness of the MSC secretome in treating various models of ED. However, the precise mechanisms of its therapeutic efficacy remain unknown. The review provided insights into the anti-inflammatory, pro-angiogenic, and trophic properties of the MSC secretome. It also discussed potential advantages, such as avoiding issues related to cellular therapy, including immunogenicity, neoplastic transformation, and cost.

Conclusion

This review underscores the significant therapeutic potential of the MSC secretome in regenerative urology, particularly for ED treatment. While preclinical studies demonstrate promising outcomes, further research is essential to elucidate the specific mechanisms underlying the therapeutic efficacy before clinical application. The review concludes by discussing future perspectives and highlighting the challenges associated with the clinical translation of the MSC secretome in regenerative urology.

Non-small cell lung cancer cells and concomitant cancer therapy induce a resistance-promoting phenotype of tumor-associated mesenchymal stem cells

Introduction

The tumor microenvironment gained attraction over the last decades as stromal cells significantly impact on tumor development, progression and metastasis, and immune evasion as well as on cancer therapy resistance. We previously reported that lung-resident mesenchymal stem cells (MSCs) were mobilized and activated in non-small cell lung cancer (NSCLC) progression and could even mediate radiation resistance in co-cultured NSCLC cells.

Methods

We investigated how MSCs were affected by NSCLC cells in combination with cancer (radiation) therapy in indirect co-cultures using tumor-conditioned medium and Transwells or direct three-dimensional NSCLC-MSC spheroid co-cultures in order to unravel the resistance-mediating action of tumor-associated MSCs.

Results

Although no obvious phenotypic and functional alterations in MSCs following NSCLC co-culture could be observed, MSC senescence was induced following co-applied radiotherapy (RT). Global gene expression profiling, in combination with gene set enrichment analysis upon treatment, was used to confirm the senescent phenotype of irradiated MSC and to reveal relevant senescence-associated secretory phenotype (SASP) factors that could meditate NSCLC RT resistance. We identified senescent tumor-associated MSC-derived serine proteinase inhibitor (serpin) E1/PAI1 as potential SASP factor mediating NSCLC progression and RT resistance.

Discussion

Specified intra-tumor-stroma interactions and cell type-specific pro-tumorigenic functions could not only improve lung cancer classification but could even be used for a more precise profiling of individual patients, finally paving an additional way for the discovery of potential drug targets for NSCLC patients.

Hematopoietic Stem Cells and Their Niche in Bone Marrow

Extensive research has explored the functional correlation between stem cells and progenitor cells, particularly in blood. Hematopoietic stem cells (HSCs) can self-renew and regenerate tissues within the bone marrow, while stromal cells regulate tissue function. Recent studies have validated the role of mammalian stem cells within specific environments, providing initial empirical proof of this functional phenomenon. The interaction between bone and blood has always been vital to the function of the human body. It was initially proposed that during evolution, mammalian stem cells formed a complex relationship with the surrounding microenvironment, known as the niche. Researchers are currently debating the significance of molecular-level data to identify individual stromal cell types due to incomplete stromal cell mapping. Obtaining these data can help determine the specific activities of HSCs in bone marrow. This review summarizes key topics from previous studies on HSCs and their environment, discussing current and developing concepts related to HSCs and their niche in the bone marrow.

Rotenone Induces a Neuropathological Phenotype in Cholinergic-like Neurons Resembling Parkinson's Disease Dementia (PDD)

Parkinson's disease with dementia (PDD) is a neurological disorder that clinically and neuropathologically overlaps with Parkinson's disease (PD) and Alzheimer's disease (AD). Although it is assumed that alpha-synuclein ( α -Syn), amyloid beta (A β ), and the protein Tau might synergistically induce cholinergic neuronal degeneration, presently the pathological mechanism of PDD remains unclear. Therefore, it is essential to delve into the cellular and molecular aspects of this neurological entity to identify potential targets for prevention and treatment strategies. Cholinergic-like neurons (ChLNs) were exposed to rotenone (ROT, 10 μ M) for 24 h. ROT provokes loss of Δ Ψ m , generation of reactive oxygen species (ROS), phosphorylation of leucine-rich repeated kinase 2 (LRRK2 at Ser935) concomitantly with phosphorylation of α -synuclein ( α -Syn, Ser129), induces accumulation of intracellular A β (iA β ), oxidized DJ-1 (Cys106), as well as phosphorylation of TAU (Ser202/Thr205), increases the phosphorylation of c-JUN (Ser63/Ser73), and increases expression of proapoptotic proteins TP53, PUMA, and cleaved caspase 3 (CC3) in ChLNs. These neuropathological features resemble those reproduced in presenilin 1 (PSEN1) E280A ChLNs. Interestingly, anti-oxidant and anti-amyloid cannabidiol (CBD), JNK inhibitor SP600125 (SP), TP53 inhibitor pifithrin- α (PFT), and LRRK2 kinase inhibitor PF-06447475 (PF475) significantly diminish ROT-induced oxidative stress (OS), proteinaceous, and cell death markers in ChLNs compared to naïve ChLNs. In conclusion, ROT induces p- α -Syn, iA β , p-Tau, and cell death in ChLNs, recapitulating the neuropathology findings in PDD. Our report provides an excellent in vitro model to test for potential therapeutic strategies against PDD. Our data suggest that ROT induces a neuropathologic phenotype in ChLNs similar to that caused by the mutation PSEN1 E280A.

Mesenchymal stromal cells derived from various tissues: Biological, clinical and cryopreservation aspects: Update from 2015 review

Mesenchymal stromal cells (MSCs) have become one of the most investigated and applied cells for cellular therapy and regenerative medicine. In this update of our review published in 2015, we show that studies continue to abound regarding the characterization of MSCs to distinguish them from other similar cell types, the discovery of new tissue sources of MSCs, and the confirmation of their properties and functions that render them suitable as a therapeutic. Because cryopreservation is widely recognized as the only technology that would enable the on-demand availability of MSCs, here we show that although the traditional method of cryopreserving cells by slow cooling in the presence of 10% dimethyl sulfoxide (Me2SO) continues to be used by many, several novel MSC cryopreservation approaches have emerged. As in our previous review, we conclude from these recent reports that viable and functional MSCs from diverse tissues can be recovered after cryopreservation using a variety of cryoprotectants, freezing protocols, storage temperatures, and periods of storage. We also show that for logistical reasons there are now more studies devoted to the cryopreservation of tissues from which MSCs are derived. A new topic included in this review covers the application in COVID-19 of MSCs arising from their immunomodulatory and antiviral properties. Due to the inherent heterogeneity in MSC populations from different sources there is still no standardized procedure for their isolation, identification, functional characterization, cryopreservation, and route of administration, and not likely to be a "one-size-fits-all" approach in their applications in cell-based therapy and regenerative medicine.

Utilization of Hydrogels in Mesenchymal Stem Cell-Based Therapy for Kidney Diseases

Kidney diseases are major global health problems, with high prevalence and mortality. However, current treatment strategies for kidney diseases fail to achieve satisfactory efficacy. Mesenchymal stem cell (MSC)-based therapy has been a promising strategy for treating kidney diseases. Preclinical studies have proven their safety and effectiveness in treating acute kidney injury (AKI) and chronic kidney disease (CKD), but the outcomes of clinical trials have shown very limited clinical efficacy. A variety of innovative approaches have been proposed to enhance the therapeutic potential of MSCs, and hydrogels are attractive candidates. Hydrogels are three-dimensional (3D) networks formed by hydrophilic polymers of natural or synthetic origin with diverse physical and chemical properties. They have been widely applied in the field of drug delivery and regenerative medicine, including MSC-based therapy. Many studies have proven that hydrogels can improve the therapeutic efficacy of MSCs for kidney diseases, but there are still challenges limiting the widespread application of this method. In this review, we introduce the application of MSCs in kidney diseases and the factors that influence therapeutic efficiency and focus on the beneficial effects of hydrogels in MSC-based therapy for AKI and CKD.

A novel role of CD73-IFNγ signalling axis in human mesenchymal stromal cell mediated inflammatory macrophage suppression

Introduction

Immunomodulation is the predominant mechanism via which Mesenchymal stromal cells (MSCs) mediate their therapeutic benefits. However, inconsistent success in numerous clinical trials warrants a better understating of the molecular mechanisms regulating their immunomodulatory properties. CD73, an ecto-5'-nucleotidase is abundantly expressed by MSCs, however its precise role in regulating their immunomodulatory properties is still elusive. The present study explored the role of CD73 in Interferon-gamma (IFNγ) sensing and in turn their ability to suppress "inflammatory" M1 macrophages.

Materials and methods

CD73 knockdown MSCs (CD73-KDN) were initially assessed for expression of immunoregulatory molecules and IFNγ sensing ability by analysing expression of IFNγ signalling downstream targets such as pSTAT-1, Interferon-Stimulated Genes (ISG) and Indoleamine 2,3-dioxygnease (IDO), a prototypic IFNγ-induced immunomodulator. Next CD73-KDN MSCs were co-cultured with inflammatory M1 macrophages and evaluated for their ability to suppress them. To delineate the contributory role of CD73 and IFNγ signalling downstream target IDO, they were overexpressed independently in CD73-KDN MSCs and re-evaluated for their ability to suppress M1 macrophages.

Results

CD73-KDN MSCs exhibited reduced expression of immunoregulatory molecules and were refractory to IFNγ signalling as indicated by attenuated expression of pSTAT-1, Interferon-Stimulated Genes (ISG) and Indoleamine 2,3-dioxygnease (IDO) upon IFNγ exposure. Since sensing of inflammation is critical for MSC mediated immunomodulation, CD73-KDN MSCs were functionally evaluated for their ability to immune-modulate "inflammatory" M1 macrophages wherein they failed to suppress M1 macrophages. Interestingly, ectopic expression of either CD73 or IFNγ signalling target IDO1 in CD73-KDN MSCs restored their ability to suppress M1 macrophages, establishing the importance of CD73-IFNγ signalling axis in MSC-mediated inflammatory macrophage suppression.

Conclusion

The present study uncovers the unexplored role of CD73-IFNγ axis in MSC-mediated M1 macrophage suppression. MSC-educated macrophages are the actual immune-modulators at MSC transplant sites, thus CD73 can serve as a key immune-potency marker for benchmarking therapeutically relevant MSCs.

Implantation of Adipose-Derived Mesenchymal Stromal Cells (ADSCs)-Lining Prosthetic Graft Promotes Vascular Regeneration in Monkeys and Pigs

BACKGROUND

Current replacement procedures for stenosis or occluded arteries using prosthetic grafts have serious limitations in clinical applications, particularly, endothelialization of the luminal surface is a long-standing unresolved problem.

METHOD

We produced a cell-based hybrid vascular graft using a bioink engulfing adipose-derived mesenchymal stromal cells (ADSCs) and a 3D bioprinting process lining the ADSCs on the luminal surface of GORE-Tex grafts. The hybrid graft was implanted as an interposition conduit to replace a 3-cm-long segment of the infrarenal abdominal aorta in Rhesus monkeys.

RESULTS

Complete endothelium layer and smooth muscle layer were fully developed within 21 days post-implantation, along with normalized collagen deposition and crosslinking in the regenerated vasculature in all monkeys. The regenerated blood vessels showed normal functionality for the longest observation of more than 1650 days. The same procedure was also conducted in miniature pigs for the interposition replacement of a 10-cm-long right iliac artery and showed the same long-term effective and safe outcome.

CONCLUSION

This cell-based vascular graft is ready to undergo clinical trials for human patients.

Review of Caplan (1991) on cell-based therapeutic technology using Mesenchymal Stem Cells

This classic discusses the original 1991 publication 'Mesenchymal Stem Cells (MSCs)' by Dr. Caplan on the emergence of a new therapeutic technology of self-cell repair using MSCs. After the original classic publication, a large number of methods to regenerate injured tissue have been reported. Currently, MSCs are used clinically to repair articular cartilage defects, liver cirrhosis, cerebral infarction, spinal cord injury, graft-versus-host disease and others. As a result, MSCs are considered one of the most important cell sources for regenerative medicine. An MSC has been demonstrated to be a multipotent stem cell in cell culture and was thought to contribute to the regeneration of injured tissue at transplant sites, but recently, the concept of MSCs has changed such that they are now referred to as "medicinal signaling cells," owing to their often indirect effects on tissue repair and regeneration. Regardless of the name, either mesenchymal stem cells or medicinal signaling cells, MSCs will be used to regenerate injured tissue more widely in the near future.

Isolation, identification and osteogenic capability analysis of mesenchymal stem cells derived from different layers of human maxillary sinus membrane

AIM

To discover the populations of mesenchymal stem cells (MSCs) derived from different layers of human maxillary sinus membrane (hMSM) and evaluate their osteogenic capability.

MATERIALS AND METHODS

hMSM was isolated into a monolayer using the combined method of physical separation and enzymatic digestion. The localization of MSCs in hMSM was performed by immunohistological staining and other techniques. Lamina propria layer-derived MSCs (LMSCs) and periosteum layer-derived MSCs (PMSCs) from hMSM were expanded using the explant cell culture method and identified by multilineage differentiation assays, colony formation assay, flow cytometry and so on. The biological characteristics of LMSCs and PMSCs were compared using RNA sequencing, reverse transcription and quantitative polymerase chain reaction, immunofluorescence staining, transwell assay, western blotting and so forth.

RESULTS

LMSCs and PMSCs from hMSMs were both CD73-, CD90- and CD105-positive, and CD34-, CD45- and HLA-DR-negative. LMSCs and PMSCs were identified as CD171+/CD90+ and CD171-/CD90+, respectively. LMSCs displayed stronger proliferation capability than PMSCs, and PMSCs presented stronger osteogenic differentiation capability than LMSCs. Moreover, PMSCs could recruit and promote osteogenic differentiation of LMSCs.

CONCLUSIONS

This study identified and isolated two different types of MSCs from hMSMs. Both MSCs served as good potential candidates for bone regeneration.

Mesenchymal Stromal Cell-Based Products: Challenges and Clinical Therapeutic Options

Mesenchymal stromal cell (MSC)-based advanced therapy medicinal products (ATMPs) are being tried in a vast range of clinical applications. These cells can be isolated from different donor tissues by using several methods, or they can even be derived from induced pluripotent stem cells or embryonic stem cells. However, ATMP heterogeneity may impact product identity and potency, and, consequently, clinical trial outcomes. In this review, we discuss these topics and the need to establish minimal criteria regarding the manufacturing of MSCs so that these innovative therapeutics may be better positioned to contribute to the advancement of regenerative medicine.

Paracrine- and cell-contact-mediated immunomodulatory effects of human periodontal ligament-derived mesenchymal stromal cells on CD4+ T lymphocytes

BACKGROUND

Mesenchymal stromal cells (MSCs) isolated from the periodontal ligament (hPDL-MSCs) have a high therapeutic potential, presumably due to their immunomodulatory properties. The interaction between hPDL-MSCs and immune cells is reciprocal and executed by diverse cytokine-triggered paracrine and direct cell-to-cell contact mechanisms. For the first time, this study aimed to directly compare the contribution of various mechanisms on this reciprocal interaction using different in vitro co-culture models at different inflammatory milieus.

METHODS

Three co-culture models were used: indirect with 0.4 μm-pored insert, and direct with or without insert. After five days of co-culturing mitogen-activated CD4+ T lymphocytes with untreated, interleukin (IL)-1β, or tumor necrosis factor (TNF)-α- treated hPDL-MSCs, the CD4+ T lymphocyte proliferation, viability, and cytokine secretion were investigated. The gene expression of soluble and membrane-bound immunomediators was investigated in the co-cultured hPDL-MSCs.

RESULTS

Untreated hPDL-MSCs decreased the CD4+ T lymphocyte proliferation and viability more effectively in the direct co-culture models. The direct co-culture model without inserts showed a strikingly higher CD4+ T lymphocyte cell death rate. Adding IL-1β to the co-culture models resulted in substantial CD4+ T lymphocyte response alterations, whereas adding TNF resulted in only moderate effects. The most changes in CD4+ T lymphocyte parameters upon the addition of IL-1β or TNF-α in a direct co-culture model without insert were qualitatively different from those observed in two other models. Additionally, the co-culture models caused variability in the immunomediator gene expression in untreated and cytokine-triggered hPDL-MSCs.

CONCLUSION

These results suggest that both paracrine and cell-to-cell contact mechanisms contribute to the reciprocal interaction between hPDL-MSCs and CD4+ T lymphocytes. The inflammatory environment affects each of these mechanisms, which depends on the type of cytokines used for the activation of MSCs' immunomodulatory activities. This fact should be considered by comparing the outcomes of the different models.

Proteomic analysis and functional validation reveal distinct therapeutic capabilities related to priming of mesenchymal stromal/stem cells with IFN-γ and hypoxia: potential implications for their clinical use

Mesenchymal stromal/stem cells (MSCs) are a heterogeneous population of multipotent cells that can be obtained from various tissues, such as dental pulp, adipose tissue, bone marrow and placenta. MSCs have gained importance in the field of regenerative medicine because of their promising role in cell therapy and their regulatory abilities in tissue repair and regeneration. However, a better characterization of these cells and their products is necessary to further potentiate their clinical application. In this study, we used unbiased high-resolution mass spectrometry-based proteomic analysis to investigate the impact of distinct priming strategies, such as hypoxia and IFN-γ treatment, on the composition and therapeutic functionality of the secretome produced by MSCs derived from the amniotic membrane of the human placenta (hAMSCs). Our investigation revealed that both types of priming improved the therapeutic efficacy of hAMSCs, and these improvements were related to the secretion of functional factors present in the conditioned medium (CM) and exosomes (EXOs), which play crucial roles in mediating the paracrine effects of MSCs. In particular, hypoxia was able to induce a pro-angiogenic, innate immune response-activating, and tissue-regenerative hAMSC phenotype, as highlighted by the elevated production of regulatory factors such as VEGFA, PDGFRB, ANGPTL4, ENG, GRO-γ, IL8, and GRO-α. IFN-γ priming, instead, led to an immunosuppressive profile in hAMSCs, as indicated by increased levels of TGFB1, ANXA1, THBS1, HOMER2, GRN, TOLLIP and MCP-1. Functional assays validated the increased angiogenic properties of hypoxic hAMSCs and the enhanced immunosuppressive activity of IFN-γ-treated hAMSCs. This study extends beyond the direct priming effects on hAMSCs, demonstrating that hypoxia and IFN-γ can influence the functional characteristics of hAMSC-derived secretomes, which, in turn, orchestrate the production of functional factors by peripheral blood cells. This research provides valuable insights into the optimization of MSC-based therapies by systematically assessing and comparing the priming type-specific functional features of hAMSCs. These findings highlight new strategies for enhancing the therapeutic efficacy of MSCs, particularly in the context of multifactorial diseases, paving the way for the use of hAMSC-derived products in clinical practice.

Bio-distribution and toxicity potential of human umbilical cord mesenchymal stem cells in cynomolgus monkeys

Mesenchymal stem cells (MSCs) have demonstrated promising advantages in the therapies of many diseases, while its multi-directional differentiation potential and immunotoxicity are the major concerns hindered their clinical translation. In this study, human umbilical Mesenchymal stem cell (hUC-MSCs) were labeled with a near-infrared fluorescent dye DiR before infused into cynomolgus monkeys, and the amount of hUC-MSCs in the peripheral blood were dynamically estimated from 5 min to 28 days post a single administration at 3 × 106 cells/kg and 2 × 107 cells/kg intravenously. As results, some hUC-MSCs distributed to the whole body within 5 min, while most of the cells accumulate in the lungs along with the systemic blood circulation, and subsequently released into the blood. The toxicity potentials of hUC-MSCs were investigated in another 30 cynomolgus monkeys, and the cells were repeatedly administrated at doses of 3 × 106 cells/kg and 2 × 107 cells/kg for 5 times on a weekly basis, with a recovery period of 1 months. hUC-MSCs showed no obvious toxic effects in cynomolgus monkeys, except xenogeneic immune rejection to human stem cells. Low levels of the hUC-MSC gene were detected in the peripheral blood of a few animals administered 2 × 107 cells/kg at 30 min subsequent to the first and last administration, and there was no significant difference in the copy number of the hUC-MSC gene in the blood samples compared with the first and last administration, indicating that the hUC-MSC was not significantly amplified in vivo, and it its safe in non-human primates. Our study for the first time verified the safety of long-term use of hUC-MSCs in primates. We have pioneered a technology for the real-time detection of hUC-MSCs in peripheral blood and provide dynamicand rapid monitoring of the distribution characteristics of hUC-MSCs in vivo. Here, we provide data supporting the application of such products for clinical treatment and the application of stem cells in major refractory diseases and regenerative medicine.

Pyroptotic macrophages induce disruption of glutamate metabolism in periodontal ligament stem cells contributing to their compromised osteogenic potential

Macrophage pyroptosis is of key importance to host defence against pathogen infections and may participate in the progression and recovery of periodontitis. However, the role of pyroptotic macrophages in regulating periodontal ligament stem cells (PDLSCs), the main cell source for periodontium renewal, remains unclear. First, we found that macrophage pyroptosis were enriched in gingiva tissues from periodontitis patients compared with those of healthy people through immunofluorescence. Then the effects of pyroptotic macrophages on the PDLSC osteogenic differentiation were investigated in a conditioned medium (CM)-based coculture system in vitro. CM derived from pyroptotic macrophages inhibited the osteogenic differentiation-related gene and protein levels, ALP activity and mineralized nodule formation of PDLSCs. The osteogenic inhibition of CM was alleviated when pyroptosis was inhibited by VX765. Further, untargeted metabolomics showed that glutamate limitation may be the underlying mechanism. However, exogenous glutamate supplementation aggravated the CM-inhibited osteogenic differentiation of PDLSCs. Moreover, CM increased extracellular glutamate and decreased intracellular glutamate levels of PDLSCs, and enhanced the gene and protein expression levels of system xc - (a cystine/glutamate antiporter). After adding cystine to CM-based incubation, the compromised osteogenic potency of PDLSCs was rescued. Our data suggest that macrophage pyroptosis is related to the inflammatory lesions of periodontitis. Either pharmacological inhibition of macrophage pyroptosis or nutritional supplements to PDLSCs, can rescue the compromised osteogenic potency caused by pyroptotic macrophages.

Role of umbilical cord mesenchymal stromal cells in skin rejuvenation

Aging is the main cause of many degenerative diseases. The skin is the largest and the most intuitive organ that reflects the aging of the body. Under the interaction of endogenous and exogenous factors, there are cumulative changes in the structure, function, and appearance of the skin, which are characterized by decreased synthesis of collagen and elastin, increased wrinkles, relaxation, pigmentation, and other aging characteristics. skin aging is inevitable, but it can be delayed. The successful isolation of mesenchymal stromal cells (MSC) in 1991 has greatly promoted the progress of cell therapy in human diseases. The International Society for Cellular Therapy (ISCT) points out that the MSC is a kind of pluripotent progenitor cells that have self-renewal ability (limited) in vitro and the potential for mesenchymal cell differentiation. This review mainly introduces the role of perinatal umbilical cord-derived MSC(UC-MSC) in the field of skin rejuvenation. An in-depth and systematic understanding of the mechanism of UC-MSCs against skin aging is of great significance for the early realization of the clinical transformation of UC-MSCs. This paper summarized the characteristics of skin aging and summarized the mechanism of UC-MSCs in skin rejuvenation reported in recent years. In order to provide a reference for further research of UC-MSCs to delay skin aging.

The Hippo signalling pathway in bone homeostasis: Under the regulation of mechanics and aging

The Hippo signalling pathway is a conserved kinase cascade that orchestrates diverse cellular processes, such as proliferation, apoptosis, lineage commitment and stemness. With the onset of society ages, research on skeletal aging-mechanics-bone homeostasis has exploded. In recent years, aging and mechanical force in the skeletal system have gained groundbreaking research progress. Under the regulation of mechanics and aging, the Hippo signalling pathway has a crucial role in the development and homeostasis of bone. We synthesize the current knowledge on the role of the Hippo signalling pathway, particularly its downstream effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), in bone homeostasis. We discuss the regulation of the lineage specification and function of different skeletal cell types by the Hippo signalling pathway. The interactions of the Hippo signalling pathway with other pathways, such as Wnt, transforming growth factor beta and nuclear factor kappa-B, are also mentioned because of their importance for modulating bone homeostasis. Furthermore, YAP/TAZ have been extensively studied as mechanotransducers. Due to space limitations, we focus on reviewing how mechanical forces and aging influence cell fate, communications and homeostasis through a dysregulated Hippo signalling pathway.

Canine Mesenchymal Stromal Cell Exosomes: State-of-the-Art Characterization, Functional Analysis and Applications in Various Diseases

Canine mesenchymal stromal cells (MSCs) possess the capacity to differentiate into a variety of cell types and secrete a wide range of bioactive molecules in the form of soluble and membrane-bound exosomes. Extracellular vesicles/exosomes are nano-sized vesicles that carry proteins, lipids, and nucleic acids and can modulate recipient cell response in various ways. The process of exosome formation is a physiological interaction between cells. With a significant increase in basic research over the last two decades, there has been a tremendous expansion in research in MSC exosomes and their potential applications in canine disease models. The characterization of exosomes has demonstrated considerable variations in terms of source, culture conditions of MSCs, and the inclusion of fetal bovine serum or platelet lysate in the cell cultures. Furthermore, the amalgamation of exosomes with various nano-materials has become a novel approach to the fabrication of nano-exosomes. The fabrication of exosomes necessitates the elimination of extrinsic proteins, thus enhancing their potential therapeutic uses in a variety of disease models, including spinal cord injury, osteoarthritis, and inflammatory bowel disease. This review summarizes current knowledge on the characteristics, biological functions, and clinical relevance of canine MSC exosomes and their potential use in human and canine research. As discussed, exosomes have the ability to control lethal vertebrate diseases by administration directly at the injury site or through specific drug delivery mechanisms.

Impact of platelet lysate on immunoregulatory characteristics of equine mesenchymal stromal cells

Multipotent mesenchymal stromal cells (MSC) play an increasing role in the treatment of immune-mediated diseases and inflammatory processes. They regulate immune cells via cell-cell contacts and by secreting various anti-inflammatory molecules but are in turn influenced by many factors such as cytokines. For MSC culture, platelet lysate (PL), which contains a variety of cytokines, is a promising alternative to fetal bovine serum (FBS). We aimed to analyze if PL with its cytokines improves MSC immunoregulatory characteristics, with the perspective that PL could be useful for priming the MSC prior to therapeutic application. MSC, activated peripheral blood mononuclear cells (PBMC) and indirect co-cultures of both were cultivated in media supplemented with either PL, FBS, FBS+INF-γ or FBS+IL-10. After incubation, cytokine concentrations were measured in supernatants and control media. MSC were analyzed regarding their expression of immunoregulatory genes and PBMC regarding their proliferation and percentage of FoxP3+ cells. Cytokines, particularly IFN-γ and IL-10, remained at high levels in PL control medium without cells but decreased in cytokine-supplemented control FBS media without cells during incubation. PBMC released IFN-γ and IL-10 in various culture conditions. MSC alone only released IFN-γ and overall, cytokine levels in media were lowest when MSC were cultured alone. Stimulation of MSC either by PBMC or by PL resulted in an altered expression of immunoregulatory genes. In co-culture with PBMC, the MSC gene expression of COX2, TNFAIP6, IDO1, CXCR4 and MHC2 was upregulated and VCAM1 was downregulated. In the presence of PL, COX2, TNFAIP6, VCAM1, CXCR4 and HIF1A were upregulated. Functionally, while no consistent changes were found regarding the percentage of FoxP3+ cells, MSC decreased PBMC proliferation in all media, with the strongest effect in FBS media supplemented with IL-10 or IFN-γ. This study provides further evidence that PL supports MSC functionality, including their immunoregulatory mechanisms. The results justify to investigate functional effects of MSC cultured in PL-supplemented medium on different types of immune cells in more detail.

Advancements in culture technology of adipose-derived stromal/stem cells: implications for diabetes and its complications

Stem cell-based therapies exhibit considerable promise in the treatment of diabetes and its complications. Extensive research has been dedicated to elucidate the characteristics and potential applications of adipose-derived stromal/stem cells (ASCs). Three-dimensional (3D) culture, characterized by rapid advancements, holds promise for efficacious treatment of diabetes and its complications. Notably, 3D cultured ASCs manifest enhanced cellular properties and functions compared to traditional monolayer-culture. In this review, the factors influencing the biological functions of ASCs during culture are summarized. Additionally, the effects of 3D cultured techniques on cellular properties compared to two-dimensional culture is described. Furthermore, the therapeutic potential of 3D cultured ASCs in diabetes and its complications are discussed to provide insights for future research.