Therapeutic Use of Mesenchymal Stromal Cells: The Need for Inclusive Characterization Guidelines to Accommodate All Tissue Sources and Species

Mesenchymal stem cells improve osteoarthritis by secreting superoxide dismutase to regulate oxidative stress response

BACKGROUND

To investigate the therapeutic effect of intraarticular injection of mesenchymal stem cells (MSC) in a rabbit osteoarthritis (OA) model. And to suppose whether MSC play a pivotal role in OA therapy by improving oxidative stress through secreting superoxide dismutase (SOD).

METHODS

MSC and chondrocytes were isolated and cultured in vitro. SOD gene of MSC was silenced by siRNA technology to prepare the SOD-siRNA-MSC for in-vivo study. Twenty healthy adult New Zealand white rabbits underwent papain injection to induce OA and then received intra-articular injection with MSC, siRNA-MSC, or normal saline. The rabbits were divided into 4 groups (n = 5), such as the control group, the model group, the MSC group, the siRNA-MSC group. Cytokines determination was performed 2 and 4 weeks after treatment. Magnetic resonance imaging (MRI) and histopathology and immunohistochemistry determination were performed 4 weeks after treatment. Normal chondrocytes, OA chondrocytes, OA chondrocytes + MSC group, and OA chondrocytes + siRNA-MSC were incubated for 24 h. Then β-galactosidase staining and reactive oxygen species (ROS) level was detected to establish the senescence of the cells.

RESULTS

COMP, TNF-α, MMP-2 and MMP-13 in the MSC group were significantly decreased compared to those in model group (P < 0.05). However, MMP2 and MMP13 in the siRNA-MSC group were not significantly decreased compared to the model group (P < 0.05). Magnetic resonance results revealed a significant improvement in cartilage and synovial membrane 4 weeks after MSC injection. Histopathology determination showed that cartilage structure was also significantly improved in MSC group. Immunohistochemical analysis revealed amelioration in the expression levels of proteoglycan, COL-2, P21 and P53 in MSC group. On the other hand, MRI, histopathologic and immunohistochemical analysis also indicated a decreased therapeutic effect with SOD-siRNA -MSC. The positive rate of β-galactosidase staining and ROS level of OA chondrocytes were significantly higher than those in normal chondrocytes, which was decreased in OA chondrocytes + MSC (P < 0.05). In addition, it was increased in OA chondrocytes + siRNA-MSC (P < 0.05).

CONCLUSION

Our study demonstrated for the first time that MSC might be a promising therapy in OA through anti-apoptosis and regeneration in chondrocyte by secreting SOD and improving oxidative stress.

Footprint-free induced pluripotent stem cells can be successfully differentiated into mesenchymal stromal cells in the feline model

BACKGROUND

Induced pluripotent stem cells (iPSCs) can propagate indefinitely and give rise to every other cell type, rendering them invaluable for disease modelling, drug development research, and usage in regenerative medicine. While feline iPSCs have been described, there are currently no reports on generating genome integration (footprint)-free iPSCs from domestic cats. Therefore, the objective of this study was to generate feline iPSCs from fetal fibroblasts using non-integrative Sendai virus (SeV) vectors carrying human transcription factors. Moreover, these iPSCs were differentiated into mesenchymal stromal cells (MSCs), which can be used as an alternative to tissue-derived MSCs.

METHODS

Feline fetal fibroblasts were transduced with CytoTune-iPS 2.0 Sendai Reprogramming vectors at recommended multiplicity of infections (MOI) and cultured for about 6 days. At 7 days post transduction cells were dissociated, replated on inactivated feeder cells and maintained in iPSC medium for 28 days with daily medium change. Emerging iPSC colonies were mechanically passaged and transferred to fresh feeder cells and further passaged every 6-8 days. Four feline iPSC lines were generated, with two selected for further in-depth characterization. Feline iPSCs were then differentiated into MSCs using a serial plating strategy and an inhibitor of the transforming growth factor-β (TGF-β) type I receptor.

RESULTS

Feline iPSCs exhibited characteristic colony morphology, high nuclear-to-cytoplasmic ratio, positive alkaline phosphatase activity, and expressed feline OCT4, SOX2, and Nanog homeobox (NANOG) stem cell markers. Expression of SeV-derived transgenes decreased during passaging to be eventually lost from the host cells and feline iPSCs could be stably maintained for over 35 passages. Feline iPSCs differentiated into embryoid bodies in vitro and did not form fully differentiated teratomas; instead, they generated in vivo masses containing mesodermal tissue derivatives when injected into immunodeficient mice. Feline iPSC-derived MSCs were plastic adherent, displayed MSC-like morphology, expressed MSC-specific surface markers, and differentiated into cells from the mesodermal lineage in vitro. RNA deep sequencing identified 1,189 differentially expressed genes in feline iPSC-derived MSCs compared to feline iPSCs.

CONCLUSION

We demonstrated the generation of footprint-free iPSCs from domestic cats and their directed differentiation potential towards MSCs. These SeV-derived feline iPSCs and iPSC-derived MSCs will provide valuable models to study feline diseases and explore novel therapeutic strategies and can serve as translational models for human health, leading to increased knowledge on disease pathogenesis and improved therapeutic interventions.

Isolation and characterization of a new SHED cell line as a standard source for stem cell research and clinical translation

BACKGROUND AND AIMS

Stem cells from human exfoliated deciduous teeth (SHED) are multi-potent mesenchymal stem/stromal cells (MSCs) and are inspected a favorable, non-invasive source beneficial to stem cell-mediated regeneration of damaged tissues. Our aim was to establish and characterize a non-immortalized SHED cell line as an accessible resource and novel platform for stem cell research and tissue regeneration studies.

METHODS

A Healthy exfoliated deciduous molar was extracted from a 12-year-old girl and shipped to an animal cell culture laboratory. Outgrowing primary cells from explanted small pulp tissues were monitored daily and characterized after passage 3 both morphologically and functionally. The SHED cell line was characterized by calculation of doubling time, cytogenetic analyses, STR analysis, adherence to cell culture flasks under standard cell culture media, and immunophenotypic analysis of specific MSC markers (CD90+, CD73+, CD34- and CD45-) using flow cytometry method. Differentiation potential to osteoblast, adipocyte, and chondrocyte was evaluated under standard differentiation media Expression of OCT-4 and NANOG genes was also assessed using RT-PCR method.

RESULTS

After the third day, SHED cells were visible. SHED cells were subcultured when they reached 90 % confluence after approximately 17 days. The doubling time of SHED cells was forty seven hours. SHED immunophenotyping showed the high expression level of CD90 (99.2 %) and CD73 (45.9 %), and approximately no expression of CD34 (0.079 %) and CD45 (0.19 %). The human origin, female gender and chromosomal normality of SHED cells was confirmed by cytogenetic analysis. The STR matching analysis showed that SHED cells are well-identified and authentic. No genetic instability and cross-contamination were observed in SHED cells.

CONCLUSIONS

This study provides a new SHED cell line with a normal karyotype and all the characteristics of MSCs, which can be used as a favorable model cell line in biomedical research and a promising source for clinical translation.

Human second-trimester fetal liver-derived mesenchymal stromal cells are more effective than adult bone marrow MSCs for their superior growth kinetics, immunomodulatory, and osteogenic potential

BACKGROUND

Mesenchymal stromal cells (MSCs) are promising candidates for cell therapy. Most of the therapeutic applications have used adult bone marrow MSCs, adipose MSCs and perinatal tissue-derived MSCs. Recent evidence suggests that MSCs from mid-gestational fetal tissues are more primitive, grow faster and are biologically more closely related to embryonic stem cells than other sources of MSCs. However, the expression of pluripotency genes raises the question of whether these genes are safe for clinical application. In this study, we demonstrated that second-trimester fetal liver-derived MSCs lack the expression of pluripotent markers and maintain their proliferative and osteogenic differentiation potential beyond passage 12. Compared to other sources, FL-MSCs exhibit characteristics that are promising for use in skeletal regeneration.

METHODS

MSCs were isolated from the second-trimester fetal liver and characterized for surface antigen expression, pluripotency marker expression and multilineage differentiation. The growth kinetics, population doubling, and number of colony-forming units were analyzed at the 3rd, 5th, 8th and 10th passages of FLMSCs and compared with those of BMMSCs. The immunomodulatory properties of FLMSCs were analyzed by a T-cell proliferation assay. The osteogenic differentiation potential of FL-MSCs was assessed at passages 3, 5, 8 and 12 and compared with that of BMMSCs.

RESULTS

We demonstrated that second-trimester fetal liver-derived MSCs exhibited a distinct fibroblast-like spindle-shaped morphology and expressed typical MSC surface antigens. Unlike first-trimester fetal MSCs, second-trimester FL-MSCs did not express pluripotent markers and showed significantly greater self-renewal and proliferative potential at higher passages and a lower apoptotic rate than BM-MSCs. Additionally, the osteogenic differentiation potential of FL-MSCs was 4-6 times greater than that of BM-MSCs at both early and late passages CONCLUSION: Our findings underscore the robust self-renewal and proliferative potential of second-trimester fetal liver-derived MSCs, which notably lack pluripotent markers. The ability of FL-MSCs to sustain osteogenic potential through multiple passages makes them promising candidates for bone tissue engineering and regenerative medicine.

Exploring the Potential of Stem Cells in Modulating Gut Microbiota and Managing Hypertension

Hypertension, commonly known as high blood pressure, is a significant health issue that increases the risk of cardiovascular diseases, stroke, and renal failure. This condition broadly encompasses both primary and secondary forms. Despite extensive research, the underlying mechanisms of systemic arterial hypertension-particularly primary hypertension, which has no identifiable cause and is affected by genetic and lifestyle agents-remain complex and not fully understood. Recent studies indicate that an imbalance in gut microbiota, referred to as dysbiosis, may promote hypertension, affecting blood pressure regulation through metabolites such as short-chain fatty acids and trimethylamine N-oxide. Current antihypertensive medications face limitations, including resistance and adherence issues, highlighting the need for novel therapeutic approaches. Stem cell therapy, an emerging field in regenerative medicine, shows promise in addressing these challenges. Stem cells, with mesenchymal stem cells being a prime example, have regenerative, anti-inflammatory, and immunomodulatory properties. Emerging research indicates that stem cells can modulate gut microbiota, reduce inflammation, and improve vascular health, potentially aiding in blood pressure management. Research has shown the positive impact of stem cells on gut microbiota in various disorders, suggesting their potential therapeutic role in treating hypertension. This review synthesizes the recent studies on the complex interactions between gut microbiota, stem cells, and systemic arterial hypertension. By offering a thorough analysis of the current literature, it highlights key insights, uncovers critical gaps, and identifies emerging trends that will inform and guide future investigations in this rapidly advancing field.

Mesenchymal Stem Cell Secretome: Potential Applications in Human Infertility Caused by Hormonal Imbalance, External Damage, or Immune Factors

Mesenchymal stem cells (MSCs) are a source of a wide range of soluble factors, including different proteins, growth factors, cytokines, chemokines, and DNA and RNA molecules, in addition to numerous secondary metabolites and byproducts of their metabolism. MSC secretome can be formally divided into secretory and vesicular parts, both of which are very important for intercellular communication and are involved in processes such as angiogenesis, proliferation, and immunomodulation. Exosomes are thought to have the same content and function as the MSCs from which they are derived, but they also have a number of advantages over stem cells, including low immunogenicity, unaltered functional activity during freezing and thawing, and a lack of tumor formation. In addition, MSC pre-treatment with various inflammatory factors or hypoxia can alter their secretomes so that it can be modified into a more effective treatment. Paracrine factors secreted by MSCs improve the survival of other cell populations by several mechanisms, including immunomodulatory (mostly anti-inflammatory) activity and anti-apoptotic activity partly based on Hsp27 upregulation. Reproductive medicine is one of the fields in which this cell-free approach has been extensively researched. This review presents the possible applications and challenges of using MSC secretome in the treatment of infertility. MSCs and their secretions have been shown to have beneficial effects in various models of female and male infertility resulting from toxic damage, endocrine disorders, trauma, infectious agents, and autoimmune origin.

Steps towards the clinical application of endometrial and menstrual fluid mesenchymal stem cells for the treatment of gynecological disorders

INTRODUCTION

The human endometrium is a highly regenerative tissue that contains mesenchymal stem/stromal cells (MSCs). These MSCs are sourced via office-based biopsies and menstrual fluid, providing a less invasive and readily available option for cell-based therapies. This review provides an update on endometrial-derived MSCs as a treatment option for gynecological diseases.

AREAS COVERED

This narrative review covers the characterization and therapeutic mechanisms of endometrium biopsy-derived MSCs (eMSCs) and menstrual fluid-derived mesenchymal stromal cells (MenSCs), highlighting similarities and differences. It also covers studies of their application in preclinical animal models and in clinical trials as potential cell-based therapies for gynecological diseases.

EXPERT OPINION

eMSCs and MenSCs from a homologous tissue source have the potential to promote regenerative activity as a treatment for gynecological diseases. Both eMSCs and MenSCs demonstrate therapeutic benefits through their paracrine activity in tissue regeneration, immunomodulation, angiogenesis, and mitigating fibrosis. Further research is essential to establish standardized isolation and characterization protocols, particularly for heterogeneous MenSCs, and to fully understand their mechanisms of action. Implementing SUSD2 magnetic bead sorting for purifying eMSCs from endometrial tissues and menstrual fluid is crucial for their use in future cell-based therapies. Optimization of production, storage, and delivery methods will maximize their therapeutic effectiveness.

Identifying differentiation markers between dermal fibroblasts and adipose-derived mesenchymal stromal cells (AD-MSCs) in human visceral and subcutaneous tissues using single-cell transcriptomics

BACKGROUND

Adipose-derived mesenchymal stromal cells (AD-MSCs) and fibroblasts are both widely used in regenerative medicine, demonstrating significant potential for personalized cell therapy. A major challenge in their use lies in their high biological similarity, encompassing morphology, differentiation capabilities, and flow cytometric markers, making their distinction difficult.

METHODS

In our study, we aimed to compare AD-MSCs obtained from two types of adipose tissue, subcutaneous and visceral, alongside skin fibroblasts. Notably, all tissue samples were sourced from the same donors. We analyzed the cells for surface antigens via flow cytometry and conducted single-cell RNA sequencing, followed by verification with quantitative PCR (qPCR).

RESULTS

Our results revealed phenotypic similarities between the isolated AD-MSCs and dermal fibroblasts, particularly in the expression of markers characteristic of AD-MSCs. However, through in-depth analyses, we identified distinct differences between these cell types. Specifically, we pinpointed 30 genes exhibiting the most significant variations in expression between AD-MSCs and fibroblasts. These genes are associated with biological processes such as tissue remodeling, cell movement, and activation in response to external stimuli. Among them, MMP1, MMP3, S100A4, CXCL1, PI16, IGFBP5, COMP were further validated using qPCR, clearly demonstrating their potential to differentiate between AD-MSCs and fibroblasts.

CONCLUSIONS

Our scRNA-seq analysis elucidates the transcriptional landscape of AD-MSCs and fibroblasts with unprecedented resolution, highlighting both the population-specific markers and the intrapopulation heterogeneity. Our findings underscore the importance of employing high-resolution techniques for cell identification.

Mesenchymal stromal cell therapy: Progress to date and future outlook

In clinical trials, mesenchymal stromal/stem cells (MSCs) have consistently demonstrated safety. However, demonstration of efficacy has been inconsistent and many MSC trials have failed to meet their efficacy endpoint. This disappointing reality is reflected by the limited number MSC therapies approved by regulatory agencies, despite the large number of MSC trials registered on clinicaltrials.gov. Notably, there has been a recent approval of an MSC therapy for pediatric graft-vs.-host disease in the United States, marking the first MSC therapy approved by the U.S. Food and Drug Administration. This review provides a background of the history and potential therapeutic value of MSCs, an overview of MSC products with regulatory approval, and a summary of registered MSC trials. It concludes with a discussion on current and ongoing challenges and questions surrounding MSC therapy that remains to be resolved before becoming available for routine clinical use outside of clinical trials.

Clinical-grade extracellular vesicles derived from umbilical cord mesenchymal stromal cells: preclinical development and first-in-human intra-articular validation as therapeutics for knee osteoarthritis

Osteoarthritis (OA) is a joint disease characterized by articular cartilage degradation. Persistent low-grade inflammation defines OA pathogenesis, with crucial involvement of pro-inflammatory M1-like macrophages. While mesenchymal stromal cells (MSC) and their small extracellular vesicles (sEV) hold promise for OA treatment, achieving consistent clinical-grade sEV products remains a significant challenge. This study aims to develop fully characterized, reproducible, clinical-grade batches of sEV derived from umbilical cord (UC)-MSC for the treatment of OA while assessing its efficacy and safety. Initially, a standardized, research-grade manufacturing protocol was established to ensure consistent sEV production. UC-MSC-sEV characterization under non-cGMP conditions showed consistent miRNA and protein profiles, suggesting their potential for standardized manufacturing. In vitro studies evaluated the efficacy, safety, and potency of sEV; animal studies confirmed their effectiveness and safety. In vitro, UC-MSC-sEV polarized macrophages to an anti-inflammatory M2b-like phenotype, through STAT1 modulation, indicating their potential to create an anti-inflammatory environment in the affected joints. In silico studies confirmed sEV's immunosuppressive signature through miRNA and proteome analysis. In an OA mouse model, sEV injected intra-articularly (IA) induced hyaline cartilage regeneration, validated by histological and μCT analyses. The unique detection of sEV signals within the knee joint over time highlights its safety profile by confirming the retention of sEV in the joint. The product development of UC-MSC-sEV involved refining, standardizing, and validating processes in compliance with GMP standards. The initial assessment of the safety of the clinical-grade product via IA administration in a first-in-human study showed no adverse effects after a 12 month follow-up period. These results support the progress of this sEV-based therapy in an early-phase clinical trial, the details of which are presented and discussed in this work. This study provides data on using UC-MSC-sEV as local therapy for OA, highlighting their regenerative and anti-inflammatory properties and safety in preclinical and a proof-of-principle clinical application.

Aberrant Wnt/β-catenin signaling in the mesenchymal stem cells of LZTFL1-depleted mice leads to increased adipogenesis, with implications for obesity

Obesity is one of the main clinical characteristics associated with the heterogeneous genetic disorder Bardet-Biedl syndrome (BBS). Leucine zipper transcription factor like 1 (LZTFL1) is a member of the BBS gene family. Our work showed that Lztfl1knockout (LZKO) mice display the obesity phenotype as early as 3 months of age. Mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into various cell types, including adipocytes. To understand the role of LZTFL1 in adipogenesis, we analyzed MSCs isolated from LZKO mouse compact bones (CB-MSCs). Compared to wildtype (WT), LZKO CB-MSCs had elongated primary cilia with tapered tips and increased levels of peroxisome proliferator-activated receptor γ (PPARγ), a key transcription factor that favors adipogenesis, and nuclear glucocorticoid receptor (GR), a transcription factor involved in Pparg activation. Also, LZKO CB-MSCs had a lower level of total β-catenin, a core factor of the antiadipogenic canonical Wnt/b-catenin signaling pathway involved in limiting the nuclear localization of GR. Interaction between caveolin1 (CAV1) and LRP6, the main receptor for canonical Wnt signaling, is known to be critical for Wnt pathway activation and β-catenin stabilization. Compared to WT cells, LZKO cells had elevated total, cell-surface, and lipid-raft-associated LRP6 and reduced CAV1, strongly indicating alterations in the components of the Wnt-signaling pathway. We show that in the absence of LZTFL1, adipogenesis-restraining Wnt/β-catenin signaling is inhibited, and adipogenesis-favorable factors are stimulated in CB-MSCs, leading to enhanced adipogenesis. Evidence provided here could help in understanding the mechanism and molecular basis of obesity in LZTFL1-defective patients.

Harnessing the ubiquitin proteasome system as a key player in stem cell biology

Intracellular proteins take part in almost every body function; thus, protein homeostasis is of utmost importance. The ubiquitin proteasome system (UPS) has a fundamental role in protein homeostasis. Its main role is to selectively eradicate impaired or misfolded proteins, thus halting any damage that could arise from the accumulation of these malfunctioning proteins. Proteasomes have a critical role in controlling protein homeostasis in all cell types, including stem cells. We will discuss the role of UPS enzymes as well as the 26S proteasome complex in stem cell biology from several angles. First, we shall overview common trends of proteasomal activity and gene expression of different proteasomal subunits and UPS enzymes upon passaging and differentiation of stem cells toward various cell lineages. Second, we shall explore the effect of modulating proteasomal activity in stem cells and navigate through the interrelation between proteasomes' activity and various proteasome-related transcription factors. Third, we will shed light on curated microRNAs and long non-coding RNAs using various bioinformatics tools that might have a possible role in regulating UPS in stem cells and possibly, upon manipulation, can enhance the differentiation process into different lineages and/or delay senescence upon cell passaging. This will help to decipher the role played by individual UPS enzymes and subunits as well as various interrelated molecular mediators in stem cells' maintenance and/or differentiation and open new avenues in stem cell research. This can ultimately provide a leap toward developing novel therapeutic interventions related to proteasome dysregulation.

Clinical updates in mesenchymal stromal cell therapy for osteoarthritis treatment

INTRODUCTION

Osteoarthritis (OA) is a common chronic musculoskeletal disease with heterogeneous clinical manifestations and variable responses to different treatments. Unfortunately, there is no effective disease modifying therapy at present that can alter the natural course of the disease. Cell therapy based on mesenchymal stromal cells (MSCs) may offer an attractive therapeutic option for OA with their multiple modes of action, particularly immune-regulatory and regenerative capacities.

AREAS COVERED

In this narrative review, updates on mode of action based on patient's data, factors that can influence the efficacy of MSC treatment, current status in clinical application of MSCs as seen from randomized, controlled OA trials are introduced as well as the author's perspectives in the future of MSCs as OA therapeutics.

EXPERT OPINION

Symptomatic relief is not sufficient to justify the high cost associated with culture-expanded stem cells. Its advantages and efficacy over simple and low risk/cost modalities should be seriously reevaluated. Also, as the short-term strategy, efforts should be made to lower the cost of MSC therapy. In the future, multiomics technology may help to predict that subgroup of patients who will favorably respond to stem cell treatment, which would enhance the cost effectiveness and therapeutic benefit of MSC therapy.

Suppressing the Aging Phenotype of Mesenchymal Stromal Cells: Are We Ready for Clinical Translation?

Mesenchymal stem/stromal cells (MSCs) are involved in the maintenance and regeneration of a large variety of tissues due to their stemness and multi-lineage differentiation capability. Harnessing these advantageous features, a flurry of clinical trials have focused on MSCs to treat different pathologies, but only few protocols have received regulatory approval so far. Among the various causes hindering MSCs' efficacy is the emergence of cellular senescence, which has been correlated with specific characteristics, such as morphological and epigenetic alterations, DNA damage, ROS production, mitochondrial dysfunction, telomere shortening, non-coding RNAs, loss of proteostasis, and a peculiar senescence-associated secretory phenotype. Several strategies have been investigated for delaying or even hopefully reverting the onset of senescence, as assessed by the senescent phenotype of MSCs. Here, the authors reviewed the most updated literature on the potential causes of senescence, with a particular emphasis on the current and future therapeutic approaches aimed at reverting senescence and/or extending the functional lifespan of stem cells.

Rabbit visceral adipose stromal cell reveals phenotype and genotype characteristics of adult mesenchymal stem cell

Background

As an excellent model for many animal and human diseases, rabbits are the third-most used mammal model after mice and rats. A plethora of studies on the exploration of rabbit mesenchymal stem cells still face discrepancies, especially in the standardization of phenotype and genotype characteristics to support reproducibility in both biomedical and translational research.

Aim

This study is aimed to evaluate the characterization and differentiation potential of visceral rabbit adipose-derived mesenchymal stem cells (Rab-ADMSC).

Methods

Visceral adipose tissue was obtained from three healthy male White New Zealand rabbits. Cells were further processed and cultivated aseptically. Phenotype and genotype assessments, including morphological observation, proliferation capacity, population doubling time, stemness- and senescence-related genes determination, a set panel of mesenchymal stem/stromal cell (MSC) surface markers evaluation, and multilineage differentiation, were performed in this study.

Results

Visceral Rab-ADMSC exhibited fibroblast-like shape morphology and had a plastic adherent ability, expressed stemness- (NANOG, SOX2) and senescence-related (TP53, CDKN1A) markers. Visceral Rab-ADMSC performs high expression of CD9, moderate expression of CD44 and CD49f, dimly expression of CD105, CD90, and CD73, and negative expression of CD13 and CD133 as well as CD45 as a hematopoietic stem cell marker. Despite these discrepancies, visceral Rab-ADMSC maintained its ability to differentiate into osteocytes, adipocytes, and chondrocytes.

Conclusion

To recapitulate, visceral Rab-ADMSC reveals the phenotype and genotype characteristics of adult mesenchymal stem cells. The study emphasizes how variations in tissue sources, culture conditions, and techniques can affect the reproducibility and validity of MSC obtained from different specific anatomical depots and species. Thus, the utilization of rabbit MSC as an animal model in biomedical and translational studies should be done with full caution to avoid data misinterpretation.

Mesenchymal stem cell therapy in veterinary ophthalmology: clinical evidence and prospects

Mesenchymal stem cell (MSC) therapy presents a promising strategy for treating various ocular conditions in veterinary medicine. This review explores the therapeutic potential of MSCs in managing corneal ulcers, immune-mediated keratitis, chronic superficial keratitis, keratoconjunctivitis sicca, retinal degeneration, and ocular burns in feline, equine, and canine patients. Studies have demonstrated the immunomodulatory and regenerative properties of MSCs, highlighting their ability to mitigate inflammation and promote tissue regeneration. Experimental studies have shown the potential of MSC therapy in reducing corneal opacity and vascularization, indicating significant therapeutic advantages. Delivery methods play a crucial role in optimizing the therapeutic efficacy of MSCs in ocular diseases. Various delivery methods, such as intravitreal injection, subconjunctival injection, topical administration, and scaffold-mediated delivery, are being explored to optimize MSC delivery to the target ocular tissues. Clinical trials have shown significant improvements in clinical signs following MSC therapy, underscoring its efficacy in treating ocular diseases. Additionally, tissue engineering approaches incorporating MSCs, growth factors, and scaffolds offer innovative strategies for corneal regeneration and tissue repair. Despite challenges such as standardization of protocols and long-term safety assessment, ongoing research endeavours seek to unlock the full therapeutic potential of MSC therapy in ocular diseases. Future prospects in MSC therapy involve exploring scaffold and hydrogel-based approaches and cell-free therapies leveraging the bioactive molecules released by MSCs. Continued research and development efforts are essential to unlock the full therapeutic potential of MSCs and realize their transformative impact on ocular diseases in veterinary patients.

Enhancing intrinsic TGF-β signaling via heparan sulfate glycosaminoglycan regulation to promote mesenchymal stem cell capabilities and chondrogenesis for cartilage repair

Osteoarthritis burdens patients due to the limited regenerative capacity of chondrocytes. Traditional cartilage repair often falls short, necessitating innovative approaches. Mesenchymal stem cells (MSCs) show promise for regeneration. Heparan sulfate glycosaminoglycans (HS-GAGs) regulate cellular functions, making them a target for cartilage repair. This study highlights how Heparinase III (HepIII) cleaves intact HS-GAGs in bone marrow-derived MSCs (BM-MSCs), enhancing their capabilities and specifically promoting chondrogenesis. HepIII-treated BM-MSCs cultured in a hanging drop device for three days, significantly increased cell number and aggregation into a cell sphere with early chondrogenesis. HepIII promoted BM-MSCs toward chondrogenesis, increasing type II collagen, intact HS-GAGs, and sulfated GAG content, while upregulating chondrogenic and heparan sulfate proteoglycan genes. Treatment with the TGF-β inhibitor (SB-431542) in HepIII-treated BM-MSCs demonstrated enhanced intrinsic transforming growth factor-β (TGF-β) signaling and fibronectin expression. This approach also boosted BM-MSC self-renewal, immunosuppressive potential, and modified acetylated histone signatures, offering a cost-effective strategy for cartilage repair by addressing inflammation, metabolic changes, and the high costs of traditional TGF-β methods. From the results, HepIII-treated BM-MSCs show potential for use in combination with other biopolymers as injectable gels to improve cartilage repair in osteoarthritis patients in the near future.

Secretome from hypoxic mesenchymal stem cells as a potential therapy for ischemic stroke: Investigations on VEGF and GFAP expression

Ischemic stroke is a sudden onset of neurological deficit resulting from a blockage in cerebral blood vessels, which can lead to brain tissue damage, chronic disability, and increased risk of mortality. Secretome from hypoxic mesenchymal stem cells (SH-MSC) is a potential therapy to improve neurological deficit by increasing the expression of vascular endothelial growth factor (VEGF) and reducing glial fibrillary acidic protein (GFAP). These effects can reduce the infarction area of ischemic stroke. Therefore, the aim of this study was to analyze the effect of 150 μL and 300 μL SH-MSC injection on VEGF and GFAP expression as well as the improvement of infarction area in ischemic stroke animal model. A post-test-only experimental design with consecutive sampling was used, with Rattus norvegicus as subjects. Stromal mesenchymal stem cells (S-MSCs) were isolated from the umbilical cords of rats at 21 days of gestation. Secretome production by the S- MSCs was induced under a hypoxic condition, and subsequently isolated. The resultant secretome was administered to rats subjected to middle cerebral artery occlusion (MCAO) at doses of 150 μL (P1 group) and 300 μL (P2 group). The results showed that the infarction area was reduced in P1 (p<0.001) and P2 groups (p<0.001). SH-MSC at a dose of 300 μL increased the expression of VEGF (p=0.028) and reduced the expression of GFAP (p=0.001). In conclusion, secretome from hypoxic S-MSC could potentially improve ischemic stroke by upregulating VEGF expression and downregulating GFAP expression.

Behavioral dynamics of medicinal signaling cells from porcine bone marrow in long-term culture

Medicinal signaling cells (MSC) hold promise for regenerative medicine due to their ability to repair damaged tissues. However, their effectiveness can be affected by how long they are cultured in the lab. This study investigated how passage number influences key properties for regenerative medicine of pig bone marrow MSC. The medicinal signiling cells derived from pig bone marrow (BM-MSC) were cultured in D-MEM High Glucose supplemented with 15% foetal bovine serum until the 25th passage and assessed their growth, viability, ability to differentiate into different cell types (plasticity), and cell cycle activity. Our findings showed that while the cells remained viable until the 25th passage, their ability to grow and differentiate declined after the 5th passage. Additionally, cells in later passages spent more time in a resting phase, suggesting reduced activity. In conclusion, the number of passages is a critical factor for maintaining ideal MSC characteristics. From the 9th passage BM-MSC exhibit decline in proliferation, differentiation potential, and cell cycle activity. Given this, it is possible to suggest that the use of 5th passage cells is the most suitable for therapeutic applications.

The Roles of Micro- and Nanoscale Materials in Cell-Engineering Systems

Customizable manufacturing of ex vivo cell engineering is driven by the need for innovations in the biomedical field and holds substantial potential for addressing current therapeutic challenges; but it is still only in its infancy. Micro- and nanoscale-engineered materials are increasingly used to control core cell-level functions in cellular engineering. By reprogramming or redirecting targeted cells for extremely precise functions, these advanced materials offer new possibilities. This influences the modularity of cell reprogramming and reengineering, making these materials part of versatile and emerging technologies. Here, the roles of micro- and nanoscale materials in cell engineering are highlighted, demonstrating how they can be adaptively controlled to regulate cellular reprogramming and core cell-level functions, including differentiation, proliferation, adhesion, user-defined gene expression, and epigenetic changes. The current reprogramming routes used to achieve pluripotency from somatic cells and the significant potential of induced pluripotent stem cell technology for translational biomedical research are covered. Recent advances in nonviral intracellular delivery modalities for cell reprogramming and their constraints are evaluated. This paper focuses on emerging physical and combinatorial approaches of intracellular delivery for cell engineering, revealing the capabilities and limitations of these routes. It is showcased how these programmable materials are continually being explored as customizable tools for inducing biophysical stimulation. Harnessing the power of micro- and nanoscale-engineered materials will be a step change in the design of cell engineering, producing a suite of powerful tools for addressing potential future challenges in therapeutic cell engineering.

Allogenic bone marrow-derived mesenchymal stromal cell-based therapy for patients with chronic low back pain: a prospective, multicentre, randomised placebo controlled trial (RESPINE study)

OBJECTIVES

To assess the efficacy of a single intradiscal injection of allogeneic bone marrow mesenchymal stromal cells (BM-MSCs) versus a sham placebo in patients with chronic low back pain (LBP).

METHODS

Participants were randomised in a prospective, double-blind, controlled study to receive either sham injection or intradiscal injection of 20 million allogeneic BM-MSC, between April 2018 and December 2022. The first co-primary endpoint was the rate of responders defined by improvement of the Visual Analogue Scale (VAS) for pain of at least 20% and 20 mm, or improvement of the Oswestry Disability Index (ODI) of 20% between baseline and month 12. The secondary structural co-primary endpoint was assessed by the disc fluid content measured by quantitative MRI T2, between baseline and month 12. Secondary endpoints included pain VAS, ODI, the Short Form (SF)-36 and the minimal clinically important difference in all timepoints (1, 3, 6, 12 and 24 months). We determined the immune response associated with allogeneic cell injection between baseline and 6 months. Serious adverse events (SAEs) were recorded.

RESULTS

114 patients were randomised (n=58, BM-MSC group; n=56, sham placebo group). At 12 months, the primary outcome was not reached (74% in the BM-MSC group vs 69% in the placebo group; p=0.77). The groups did not differ in all secondary outcomes. No SAE related to the intervention occurred.

CONCLUSIONS

While our study did not conclusively demonstrate the efficacy of allogeneic BM-MSCs for LBP, the procedure was safe. Long-term outcomes of MSC therapy for LBP are still being studied.

TRIAL REGISTRATION NUMBER

EudraCT 2017-002092-25/ClinicalTrials.gov: NCT03737461.

Harnessing the Therapeutic Potential of Mesenchymal Stem Cells in Cancer Treatment

Cancer, as a complicated disease, is considered to be one of the major leading causes of death globally. Although various cancer therapeutic strategies have been established, however, some issues confine the efficacies of the treatments. In recent decades researchers for finding efficient therapeutic solutions have extensively focused on the abilities of stem cells in cancer inhibition. Mesenchymal stem cells (MSCs) are multipotent stromal cells that can the most widely extracted from various sources such as the bone marrow (BM), placenta, umbilical cord (UC), menses blood, Wharton's jelly (WJ), adipose tissue and dental pulp (DP). These cells are capable of differentiating into the osteoblasts, chondrocytes, and adipocytes. Due to the unique characteristics of MSCs such as paracrine effects, immunomodulation, tumor-tropism, and migration, they are considered promising candidates for cancer therapeutics. Currently, MSCs are an excellent living carrier for delivery of therapeutic genes and chemical agents to target tumor sites. Also, exosomes, the most important extracellular vesicle released from MSCs, act as a strong cell-free tool for cancer therapeutics. MSCs can prevent cancer progression by inhibiting several signaling pathways, such as wnt/β-catenin and PI3K/AKT/mTOR. However, there are several challenges associated with the use of MSCs and their exosomes in the field of therapy that need to be considered. This review explores the significance of MSCs in cell-based therapy, focusing on their homing properties and immunomodulatory characteristics. It also examines the potential of using MSCs as carriers for delivery of anticancer agents and their role in modulating the signal transduction pathways of cancer cells.

Morinda officinalis polysaccharide boosts osteogenic differentiation of bone marrow mesenchymal stem cells by Wnt/β-catenin signaling

OBJECTIVES

To investigate the role of Morinda officinalis polysaccharide (MOP) in the protein expression of the Wnt/β-catenin signaling cascade during the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and to elucidate the mechanisms by which MOP enhances osteogenic differentiation at the cellular level.

METHODS

BMSCs were isolated and cultured using the whole bone marrow adherence method, followed by flow cytometry for the detection of BMSC marker antigens. Two groups were prepared: a low-dose MOP (L-MOP, 10 µg/mL) group and a high-dose MOP (H-MOP, 40 µg/mL) group. MTT assays and cell clone formation assays were performed to evaluate the effects of different MOP doses on BMSC proliferation. Alizarin red staining (ARS) and alkaline phosphatase (ALP) staining were conducted to assess the impact of varying MOP doses on nodule calcification and ALP activity in BMSCs. Additionally, western blot assays were carried out to determine the effects of different MOP concentrations on the expression levels of osteogenesis-related factors and Wnt/β-catenin pathway proteins in BMSCs.

RESULTS

Highly purified BMSCs were successfully extracted. Subsequent assays demonstrated that BMSCs exhibited enhanced proliferation at all MOP doses, particularly at the H-MOP dose, compared to the control group. Both L-MOP and H-MOP increased calcium content and ALP activity in BMSCs, as well as elevated the expression of osteogenic factors and Wnt/β-catenin pathway proteins compared to the blank control group. However, the addition of Dickkopf-1 (DKK1) significantly reduced BMSC proliferation and osteogenic differentiation compared to the H-MOP group.

CONCLUSIONS

MOP can enhance BMSC proliferation and osteogenic differentiation by activating the Wnt/β-catenin signaling pathway.

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.

Persistent tailoring of MSC activation through genetic priming

Mesenchymal stem/stromal cells (MSCs) are an attractive platform for cell therapy due to their safety profile and unique ability to secrete broad arrays of immunomodulatory and regenerative molecules. Yet, MSCs are well known to require preconditioning or priming to boost their therapeutic efficacy. Current priming methods offer limited control over MSC activation, yield transient effects, and often induce the expression of pro-inflammatory effectors that can potentiate immunogenicity. Here, we describe a genetic priming method that can both selectively and sustainably boost MSC potency via the controlled expression of the inflammatory-stimulus-responsive transcription factor interferon response factor 1 (IRF1). MSCs engineered to hyper-express IRF1 recapitulate many core responses that are accessed by biochemical priming using the proinflammatory cytokine interferon-γ (IFN-γ). This includes the upregulation of anti-inflammatory effector molecules and the potentiation of MSC capacities to suppress T cell activation. However, we show that IRF1-mediated genetic priming is much more persistent than biochemical priming and can circumvent IFN-γ-dependent expression of immunogenic MHC class II molecules. Together, the ability to sustainably activate and selectively tailor MSC priming responses creates the possibility of programming MSC activation more comprehensively for therapeutic applications.

Translational potential of mesenchymal stem cells in regenerative therapies for human diseases: challenges and opportunities

Advances in stem cell technology offer new possibilities for patients with untreated diseases and disorders. Stem cell-based therapy, which includes multipotent mesenchymal stem cells (MSCs), has recently become important in regenerative therapies. MSCs are multipotent progenitor cells that possess the ability to undergo in vitro self-renewal and differentiate into various mesenchymal lineages. MSCs have demonstrated promise in several areas, such as tissue regeneration, immunological modulation, anti-inflammatory qualities, and wound healing. Additionally, the development of specific guidelines and quality control methods that ultimately result in the therapeutic application of MSCs has been made easier by recent advancements in the study of MSC biology. This review discusses the latest clinical uses of MSCs obtained from the umbilical cord (UC), bone marrow (BM), or adipose tissue (AT) in treating various human diseases such as pulmonary dysfunctions, neurological disorders, endocrine/metabolic diseases, skin burns, cardiovascular conditions, and reproductive disorders. Additionally, this review offers comprehensive information regarding the clinical application of targeted therapies utilizing MSCs. It also presents and examines the concept of MSC tissue origin and its potential impact on the function of MSCs in downstream applications. The ultimate aim of this research is to facilitate translational research into clinical applications in regenerative therapies.

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.

Spheroid trilineage differentiation model of primary mesenchymal stem/stromal cells under hypoxia and serum-free culture conditions

Due to their unique properties, human mesenchymal stem/stromal cells (MSCs) possess tremendous potential in regenerative medicine, particularly in cell-based therapies where the multipotency and immunomodulatory characteristics of MSCs can be leveraged to address a variety of disease states. Although MSC-based cell therapeutics have emerged as one of the most promising medical treatments, the clinical translation is hampered by the variability of MSC-based cellular products caused by tissue source-specific differences and the lack of physiological cell culture approaches that closely mimic the human cellular microenvironment. In this study, a model for trilineage differentiation of primary adipose-, bone marrow-, and umbilical cord-derived MSCs into adipocytes, chondrocytes and osteoblasts was established and characterized. Differentiation was performed in spheroid culture, using hypoxic conditions and serum-free and antibiotics-free medium. This platform was characterized for spheroid diameter and trilineage differentiation capacity reflecting functionality of differentiated cells, as indicated by lineage-specific extracellular matrix (ECM) accumulation and expression of distinct secreted markers. The presented model shows spheroid growth during the course of differentiation and successfully supports trilineage differentiation for MSCs from almost all tissue sources except for osteogenesis of umbilical cord-derived MSCs. These findings indicate that this platform provides a suitable and favorable environment for trilineage differentiation of MSCs from various tissue sources. Therefore, it poses a promising model to generate highly relevant biological data urgently required for clinical translation and therefore might be used in the future to generate in vitro microtissues, building blocks for tissue engineering or as disease models.

Dual production of human mesenchymal stromal cells and derived extracellular vesicles in a dissolvable microcarrier-based stirred culture system

BACKGROUND & AIMS

Cell therapies based on mesenchymal stromal cells (MSCs) have gained an increasing therapeutic interest in the context of multiple disorders. Nonetheless, this field still faces important challenges, particularly concerning suitable manufacturing platforms. Here, we aimed at establishing a scalable culture system to expand umbilical cord-derived Wharton's jelly MSC (MSC(WJ)) and their derived extracellular vesicles (EVs) by using dissolvable microcarriers combined with xeno(geneic)-free culture medium.

METHODS

MSC(WJ) isolated from three donors were cultured at a starting density of 1 × 106 cells per spinner flask, i.e., 2.8 × 103 cells per cm2 of dissolvable microcarrier surface area. After a 6-day expansion period of MSC(WJ), extracellular vesicles (EVs) were produced for 24 h.

RESULTS

Taking advantage of an intermittent agitation regimen, we observed high adhesion rates to the microcarriers (over 90% at 24 h) and achieved 15.8 ± 0.7-fold expansion after 6 days of culture. Notably, dissolution of the microcarriers was achieved through a pectinase-based solution to recover the cell product, reducing the hurdles of downstream processing. MSC identity was validated by detecting the characteristic MSC immunophenotype and by multilineage differentiation assays. Considering the growing interest in MSC-derived EVs, which are known to be mediators of the therapeutic features of MSC, this platform also was evaluated for EV production. Upon a 24-h period of conditioning, secreted EVs were isolated by ultrafiltration followed by anion-exchange chromatography and exhibited the typical cup-shaped morphology, small size distribution (162.6 ± 30.2 nm) and expressed EV markers (CD63, CD9 and syntenin-1).

CONCLUSIONS

Taken together, we established a time-effective and robust scalable platform that complies with clinical-grade standards for the dual production of MSC(WJ) and their derived EV.

Application of mesenchymal stromal cell sheets to prevent medication-related osteonecrosis of the jaw with titanium implants in rats

Medication-related osteonecrosis of the jaw (MRONJ) is an intractable adverse event. Dental implants are one of the triggering factors of MRONJ, and implant therapy with low MRONJ risk is required. This study aimed to investigate a rat model of MRONJ induced by extraoral placement of titanium materials and the use of mesenchymal stromal cell (MSCs) sheets to prevent MRONJ. Eight-week-old male rats were administered zoledronate and dexamethasone thrice weekly until killing. A week after drug initiation, a titanium screw and a plate were placed on the left buccal side of the mandible. Allogeneic bone marrow-derived MSC sheets were co-grafted with the titanium plates in the MSC sheet ( +) group. Six weeks after titanium placement, the rats were killed, and their excised mandibular bones were subjected to micro-computed tomography (CT) analysis. Histological analysis was performed after the titanium implants were removed. Empty lacunae visualized on hematoxylin and eosin staining were used as evidence of bone necrosis. Bone necrosis was reduced in the MSC sheet ( +) group. Tartrate-resistant acid phosphatase (TRAP) staining revealed a decreased number of TRAP-positive cells in areas with a large number of empty lacunae in the MSC sheet (-) group. Micro-CT analyses demonstrated that the bone volume fraction (BV/TV) was not significantly different between the MSC sheet (-) and ( +) groups. We conclude that MRONJ can be triggered by a titanium placement in rats, and grafting of allogeneic MSC sheets has the potential to prevent MRONJ.

The Past, Present, and Future of Tubular Melt Electrowritten Constructs to Mimic Small Diameter Blood Vessels - A Stable Process?

Melt Electrowriting (MEW) is a continuously growing manufacturing platform. Its advantage is the consistent production of micro- to nanometer fibers, that stack intricately, forming complex geometrical shapes. MEW allows tuning of the mechanical properties of constructs via the geometry of deposited fibers. Due to this, MEW can create complex mechanics only seen in multi-material compounds and serve as guiding structures for cellular alignment. The advantage of MEW is also shown in combination with other biotechnological manufacturing methods to create multilayered constructs that increase mechanical approximation to native tissues, biocompatibility, and cellular response. These features make MEW constructs a perfect candidate for small-diameter vascular graft structures. Recently, studies have presented fascinating results in this regard, but is this truly the direction that tubular MEW will follow or are there also other options on the horizon? This perspective will explore the origins and developments of tubular MEW and present its growing importance in the field of artificial small-diameter vascular grafts with mechanical modulation and improved biomimicry and the impact of it in convergence with other manufacturing methods and how future technologies like AI may influence its progress.

Integration of Electrospun Scaffolds and Biological Polymers for Enhancing the Delivery and Efficacy of Mesenchymal Stem/Stromal Cell Therapies

Mesenchymal stem/stromal cells (MSCs) have emerged as a promising therapeutic approach for a variety of diseases due to their immunomodulatory and tissue regeneration capabilities. Despite their potential, the clinical application of MSC therapies is hindered by limited cell retention and engraftment at the target sites. Electrospun scaffolds, with their high surface area-to-volume ratio and tunable physicochemical properties, can be used as platforms for MSC delivery. However, synthetic polymers often lack the bioactive cues necessary for optimal cell-scaffold interactions. Integrating electrospun scaffolds and biological polymers, such as polysaccharides, proteins, and composites, combines the mechanical integrity of synthetic materials with the bioactivity of natural polymers and represents a strategic approach to enhance cell-scaffold interactions. The molecular interactions between MSCs and blended or functionalized scaffolds have been examined in recent studies, and it has been shown that integration can enhance MSC adhesion, proliferation, and paracrine secretion through the activation of multiple signaling pathways, such as FAK/Src, MAPK, PI3K/Akt, Wnt/β-catenin, and YAP/TAZ. Preclinical studies on small animals also reveal that the integration of electrospun scaffolds and natural polymers represents a promising approach to enhancing the delivery and efficacy of MSCs in the context of regenerating bone, cartilage, muscle, cardiac, vascular, and nervous tissues. Future research should concentrate on identifying the distinct characteristics of the MSC niche, investigating the processes involved in MSC-scaffold interactions, and applying new technologies in stem cell treatment and biofabrication to enhance scaffold design. Research on large animal models and collaboration among materials scientists, engineers, and physicians are crucial to translating these advancements into clinical use.

Controversies regarding transplantation of mesenchymal stem cells

Mesenchymal stem cells (MSCs) have tantalized regenerative medicine with their therapeutic potential, yet a cloud of controversies looms over their clinical transplantation. This comprehensive review navigates the intricate landscape of MSC controversies, drawing upon 15 years of clinical experience and research. We delve into the fundamental properties of MSCs, exploring their unique immunomodulatory capabilities and surface markers. The heart of our inquiry lies in the controversial applications of MSC transplantation, including the perennial debate between autologous and allogeneic sources, concerns about efficacy, and lingering safety apprehensions. Moreover, we unravel the enigmatic mechanisms surrounding MSC transplantation, such as homing, integration, and the delicate balance between differentiation and paracrine effects. We also assess the current status of clinical trials and the ever-evolving regulatory landscape. As we peer into the future, we examine emerging trends, envisioning personalized medicine and innovative delivery methods. Our review provides a balanced and informed perspective on the controversies, offering readers a clear understanding of the complexities, challenges, and potential solutions in MSC transplantation.

Advantages of pooling of human bone marrow-derived mesenchymal stromal cells from different donors versus single-donor MSCs

Mesenchymal stromal cells (MSC) from adult bone marrow are the most commonly used cells in clinical trials. MSCs from single donors are the preferred starting material but suffer from a major setback of being heterogeneous that results in unpredictable and inconsistent clinical outcomes. To overcome this, we developed a method of pooling MSCs from different donors and created cell banks to cater clinical needs. Initially, the master cell banks (MCBs) were created at passage 1 (P1) from the bone marrow MSCs isolated from of nine different donors. At this stage, MCBs from three different donors were mixed in equal proportion and expanded till P3 to create working cell banks. Further, the pooled cells and individual donor MSCs were expanded till P5 and cryopreserved and extensively characterised. There was a large heterogeneity among the individual donor MSCs in terms of growth kinetics (90% Coefficient of variation (CV) for cell yield and 44% CV for population doubling time at P5), immunosuppressive ability (30% CV at 1:1 and 300% CV at 1:10 ratio), and the angiogenic factor secretion potential (20% CV for VEGF and71% CV for SDF-1). Comparatively, the pooled cells have more stable profiles (60% CV for cell yield and 7% CV for population doubling time at P5) and exhibit better immunosuppressive ability (15% CV at 1:1 and 32% CV at 1:10 ratio ) and consistent secretion of angiogenic factors (16% CV for VEGF and 51% CV for SDF-1). Further pooling does not compromise the trilineage differentiation capacity or phenotypic marker expression of the MSCs. The senescence and in vitro tumourigenicity characteristics of the pooled cells are also similar to those of individual donor MSCs. We conclude that pooling of MSCs from three different donors reduces heterogeneity among individual donors and produces MSCs with a consistent secretion and higher immunosuppressive profile.

Current Strategies and Therapeutic Applications of Mesenchymal Stem Cell-Based Drug Delivery

Mesenchymal stem cells (MSCs) have emerged as a promising approach for drug delivery strategies because of their unique properties. These strategies include stem cell membrane-coated nanoparticles, stem cell-derived extracellular vesicles, immunomodulatory effects, stem cell-laden scaffolds, and scaffold-free stem cell sheets. MSCs offer advantages such as low immunogenicity, homing ability, and tumor tropism, making them ideal for targeted drug delivery systems. Stem cell-derived extracellular vesicles have gained attention for their immune properties and tumor-homing abilities, presenting a potential solution for drug delivery challenges. The relationship between MSC-based drug delivery and the self-renewal and differentiation capabilities of MSCs lies in the potential of engineered MSCs to serve as effective carriers for therapeutic agents while maintaining their intrinsic properties. MSCs exhibit potent immunosuppressive functions in MSC-based drug delivery strategies. Stem cell-derived EVs have low immunogenicity and strong therapeutic potential for tissue repair and regeneration. Scaffold-free stem cell sheets represent a cutting-edge approach in regenerative medicine, offering a versatile platform for tissue engineering and regeneration across different medical specialties. MSCs have shown great potential for clinical applications in regenerative medicine because of their ability to differentiate into various cell types, secrete bioactive factors, and modulate immune responses. Researchers are exploring these innovative approaches to enhance drug delivery efficiency and effectiveness in treating various diseases.

A GMP-compliant manufacturing method for Wharton's jelly-derived mesenchymal stromal cells

BACKGROUND

Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) hold great therapeutic potential in regenerative medicine. Therefore, it is crucial to establish a Good Manufacturing Practice (GMP)-compliant methodology for the isolation and culture of WJ-MSCs. Through comprehensive research, encompassing laboratory-scale experiments to pilot-scale studies, we aimed to develop standardized protocols ensuring the high yield and quality of WJ-MSCs manufacturing.

METHODS

Firstly, optimization of parameters for the enzymatic digestion method used to isolate WJ-MSCs was conducted. These parameters included enzyme concentrations, digestion times, seeding densities, and culture media. Additionally, a comparative analysis between the explant method and the enzymatic digestion method was performed. Subsequently, the consecutive passaging of WJ-MSCs, specifically up to passage 9, was evaluated using the optimized method. Finally, manufacturing processes were developed and scaled up, starting from laboratory-scale flask-based production and progressing to pilot-scale cell factory-based production. Furthermore, a stability study was carried out to assess the storage and use of drug products (DPs).

RESULTS

The optimal parameters for the enzymatic digestion method were a concentration of 0.4 PZ U/mL Collagenase NB6 and a digestion time of 3 h, resulting in a higher yield of P0 WJ-MSCs. In addition, a positive correlation between the weight of umbilical cord tissue and the quantities of P0 WJ-MSCs has been observed. Evaluation of different concentrations of human platelet lysate revealed that 2% and 5% concentrations resulted in similar levels of cell expansion. Comparative analysis revealed that the enzymatic digestion method exhibited faster outgrowth of WJ-MSCs compared to the explant method during the initial passage. Passages 2 to 5 exhibited higher viability and proliferation ability throughout consecutive passaging. Moreover, scalable manufacturing processes from the laboratory scale to the pilot scale were successfully developed, ensuring the production of high-quality WJ-MSCs. Multiple freeze-thaw cycles of the DPs led to reduced cell viability and viable cell concentration. Subsequent thawing and dilution of the DPs resulted in a significant decrease in both metrics, especially when stored at 20-27 °C.

CONCLUSION

This study offers valuable insights into optimizing the isolation and culture of WJ-MSCs. Our scalable manufacturing processes facilitate the large-scale production of high-quality WJ-MSCs. These findings contribute to the advancement of WJ-MSCs-based therapies in regenerative medicine.

A comprehensive review on the role of mesenchymal stromal/stem cells in the management of rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease with systemic manifestations. Although the success of immune modulatory drug therapy is considerable, about 40% of patients do not respond to treatment. Mesenchymal stromal/stem cells (MSCs) have been demonstrated to have therapeutic potential for inflammatory diseases.

AREAS COVERED

This review provides an update on RA disease and on pre-clinical and clinical studies using MSCs from bone marrow, umbilical cord, adipose tissue, and dental pulp, to regulate the immune response. Moreover, the clinical use, safety, limitations, and future perspective of MSCs in RA are discussed. Using the PubMed database and ClincalTrials.gov, peer-reviewed full-text papers, abstracts and clinical trials were identified from 1985 through to April 2023.

EXPERT OPINION

MSCs demonstrated a satisfactory safety profile and potential for clinical efficacy. However, it is mandatory to deepen the investigations on how MSCs affect the proinflammatory deregulated RA patients' cells. MSCs are potentially good candidates for severe RA patients not responding to conventional therapies but a long-term follow-up after stem cells treatment and standardized protocols are needed. Future research should focus on well-designed multicenter randomized clinical trials with adequate sample sizes and properly selected patients satisfying RA criteria for a valid efficacy evaluation.

Apoptosis in Postmortal Tissues of Goat Spinal Cords and Survival of Resident Neural Progenitors

Growing demand for therapeutic tissue repair recurrently focusses scientists' attention on critical assessment of postmortal collection of live cells, especially stem cells. Our study aimed to assess the survival of neuronal progenitors in postmortal spinal cord and their differentiation potential. Postmortal samples of spinal cords were obtained from human-sized animals (goats) at 6, 12, 24, 36, and 54 h after slaughter. Samples were studied by immunohistology, differentiation assay, Western blot and flow cytometry for the presence and location of GD2-positive neural progenitors and their susceptibility to cell death. TUNEL staining of the goat spinal cord samples over 6-54 h postmortem revealed no difference in the number of positive cells per cross-section. Many TUNEL-positive cells were located in the gray commissure around the central canal of the spinal cord; no increase in TUNEL-positive cells was recorded in either posterior or anterior horns of the gray matter where many GD2-positive neural progenitors can be found. The active caspase 3 amount as measured by Western blot at the same intervals was moderately increasing over time. Neuronal cells were enriched by magnetic separation with antibodies against CD24; among them, the GD2-positive neural progenitor subpopulation did not overlap with apoptotic cells having high pan-caspase activity. Apoptotic cell death events are relatively rare in postmortal spinal cords and are not increased in areas of the neural progenitor cell's location, within measured postmortal intervals, or among the CD24/GD2-positive cells. Data from our study suggest postmortal spinal cords as a valuable source for harvesting highly viable allogenic neural progenitor cells.

Alveolar mucosal cell spheroids promote extraction socket healing and osseous defect regeneration

BACKGROUND

Alveolar mucosa could be a promising source of mesenchymal stem cells (MSCs) for regeneration therapeutics because it exhibits faster healing potential and can be easily collected with minimal periodontal disturbance. This study aimed to evaluate the potential of alveolar mucosal cell (AMC) spheroids for promoting extraction socket healing and calvarial osseous defect regeneration.

METHODS

AMCs were isolated from Sprague-Dawley rats. Antigenic and MSC surface marker expressions and trilineage differentiation capability were assessed. AMCs were then osteogenically stimulated (OAs) or unstimulated (UAs), self-aggregated to form spheroids, and encapsulated in gelatin hydrogel to fill rat extraction sockets or combined with freeze-dried bone graft (FDBG) to fill rat calvarial osseous defects. The outcome was assessed by gross observation, micro-CT imaging, and immunohistochemistry.

RESULTS

AMCs highly expressed MSC surface markers, showed weak antigenicity, and were capable of trilineage differentiation at Passage 3. In the extraction sockets, wound closure, socket fill, keratinization, and proliferative activities were accelerated in those with AMC spheroids treatment. Socket fill and maturation were further promoted by OA spheroids. In the calvarial osseous defects, the mineralized tissue ratio was promoted with AMC spheroids/FDBG treatment, and bone sialoprotein expression and cell proliferation were more evident with OA spheroids/FDBG treatment.

CONCLUSION

AMCs exhibited MSC properties with weak antigenicity. AMC spheroids promoted extraction socket healing, AMC spheroids/FDBG promoted calvarial osseous defect regeneration, and the outcomes were further enhanced by osteogenically stimulation of AMCs.

Turning Trash Into Treasure: A Simple Protocol for Human Mesenchymal Stromal Cell Isolation From Used Bone Marrow Collection Kits

The therapeutic potential of mesenchymal stromal cells (MSCs) has been extensively investigated in both preclinical and clinical settings. Recent years have witnessed the emergence of numerous isolation protocols and culture techniques, ranging from the selection of subpopulations to preserve stemness to preconditioning strategies aimed at enhancing therapeutic efficacy, tailored to the specific tissue source. In this protocol, we present a straightforward and cost-effective method for isolating human MSCs (hMSCs) from discarded bone marrow collection kits (comprising bag and filter systems) originally intended for removing impurities and unwanted cellular debris from the collected bone marrow aspirate, ensuring the purity of the stem cell population during stem cell transplantation. Utilizing basic laboratory equipment, we demonstrate the isolation of hMSCs, highlighting the expression of specific surface antigens, and multilineage differentiation into adipogenic, osteogenic, and chondrogenic lineages in vitro. This sustainable and resource-efficient approach not only contributes to reducing medical waste but also holds promise for advancing regenerative medicine applications. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Isolation of human mesenchymal stromal cells from bone marrow collection kits Basic Protocol 2: Culture of human mesenchymal stromal cells Basic Protocol 3: Characterization of human mesenchymal stromal cells with flow cytometry analysis Basic Protocol 4: Characterization of human mesenchymal stromal cells with multilineage differentiation under in vitro conditions.

Signaling crosstalk between mesenchymal stem cells and tumor cells: Implications for tumor suppression or progression

Mesenchymal stem cells (MSCs) have been extensively used in various therapeutic applications over the last two decades, particularly in regenerative medicine and cancer treatment. MSCs have the ability to differentiate into mesodermal and non-mesodermal lineages, which makes them a popular choice in tissue engineering and regenerative medicine. Studies have shown that MSCs have inherent tumor-suppressive properties and can affect the behavior of multiple cells contributing to tumor development. Additionally, MSCs possess a tumor tropism property and have a hypoimmune nature. The intrinsic features of MSCs along with their potential to undergo genetic manipulation and be loaded with various anticancer therapeutics have motivated researchers to use them in different cancer therapy approaches without considering their complex dynamic biological aspects. However, despite their desirable features, several reports have shown that MSCs possess tumor-supportive properties. These contradictory results signify the sophisticated nature of MSCs and warn against the potential therapeutic applications of MSCs. Therefore, researchers should meticulously consider the biological properties of MSCs in preclinical and clinical studies to avoid any undesirable outcomes. This manuscript reviews preclinical studies on MSCs and cancer from the last two decades, discusses how MSC properties affect tumor progression and explains the mechanisms behind tumor suppressive and supportive functions. It also highlights critical cellular pathways that could be targeted in future studies to improve the safety and effectiveness of MSC-based therapies for cancer treatment. The insights obtained from this study will pave the way for further clinical research on MSCs and development of more effective cancer treatments.

An Overview of Mesenchymal Stem Cell Heterogeneity and Concentration

Mesenchymal stem cells (MSCs) are of great interest in cell therapies due to the immunomodulatory and other effects they have after autologous or allogeneic transplantation. In most clinical applications, a high number of MSCs is required; therefore, the isolated MSC population must be expanded in the cell culture until the desired number is reached. Analysing freshly isolated MSCs is challenging due to their rareness and heterogeneity, which is noticeable among donors, tissues, and cell subpopulations. Although the phenotype of MSCs in tissue can differ from those of cultured cells, phenotyping and counting are usually performed only after MSC proliferation. As MSC applicability is a developing and growing field, there is a need to implement phenotyping and counting methods for freshly isolated MSCs, especially in new one-step procedures where isolated cells are implanted immediately without cell culturing. Only by analysing harvested cells can we correctly evaluate such studies. This review describes multilevel heterogeneity and concentrations of MSCs and different strategies for phenotype determination and enumeration of freshly isolated MSCs.

Comparative transcriptomic analysis of bovine mesenchymal stromal cells reveals tissue-source and species-specific differences

Mesenchymal stromal cells (MSCs) have the potential to be used as therapeutics, but their efficacy varies due to cellular heterogeneity, which is not fully understood. After characterizing donor-matched bovine MSC from adipose tissue (AT), bone marrow (BM), and peripheral blood (PB), we performed single-cell RNA sequencing (scRNA-seq) to evaluate overarching similarities and differences across these three tissue-derived MSCs. Next, the transcriptomic profiles of the bovine MSCs were compared to those of equine MSCs, derived from the same tissue sources and previously published by our group, and revealed species-specific differences. Finally, the transcriptomic profile from bovine BM-MSCs was compared to mouse and human BM-MSCs and demonstrated that bovine BM-MSCs share more common functionally relevant gene expression profiles with human BM-MSCs than compared to murine BM-MSCs. Collectively, this study presents the cow as a potential non-traditional animal model for translational MSC studies based on transcriptomic profiles similar to human MSCs.

Translation of cell therapies to treat autoimmune disorders

Autoimmune diseases are a diverse and complex set of chronic disorders with a substantial impact on patient quality of life and a significant global healthcare burden. Current approaches to autoimmune disease treatment comprise broadly acting immunosuppressive drugs that lack disease specificity, possess limited efficacy, and confer undesirable side effects. Additionally, there are limited treatments available to restore organs and tissues damaged during the course of autoimmune disease progression. Cell therapies are an emergent area of therapeutics with the potential to address both autoimmune disease immune dysfunction as well as autoimmune disease-damaged tissue and organ systems. In this review, we discuss the pathogenesis of common autoimmune disorders and the state-of-the-art in cell therapy approaches to (1) regenerate or replace autoimmune disease-damaged tissue and (2) eliminate pathological immune responses in autoimmunity. Finally, we discuss critical considerations for the translation of cell products to the clinic.

The MSC-EV-microRNAome: A Perspective on Therapeutic Mechanisms of Action in Sepsis and ARDS

Mesenchymal stromal cells (MSCs) and MSC-derived extracellular vesicles (EVs) have emerged as innovative therapeutic agents for the treatment of sepsis and acute respiratory distress syndrome (ARDS). Although their potential remains undisputed in pre-clinical models, this has yet to be translated to the clinic. In this review, we focused on the role of microRNAs contained in MSC-derived EVs, the EV microRNAome, and their potential contribution to therapeutic mechanisms of action. The evidence that miRNA transfer in MSC-derived EVs has a role in the overall therapeutic effects is compelling. However, several questions remain regarding how to reconcile the stochiometric issue of the low copy numbers of the miRNAs present in the EV particles, how different miRNAs delivered simultaneously interact with their targets within recipient cells, and the best miRNA or combination of miRNAs to use as therapy, potency markers, and biomarkers of efficacy in the clinic. Here, we offer a molecular genetics and systems biology perspective on the function of EV microRNAs, their contribution to mechanisms of action, and their therapeutic potential.

High-Throughput Multiparametric Quantification of Mechanics Driven Heterogeneity in Mesenchymal Stromal Cell Population

Mesenchymal stromal or stem cells (MSCs) are one of the most promising candidates for a myriad of cell therapy applications. Despite showing promise in numerous preclinical and clinical studies, MSC-based therapy is not yet a reality for regenerative medicine due to its suboptimal outcome at the clinical endpoint. The mechanical environment is a critical determinant of MSC gene expression and function. This study reports that MSC population becomes phenotypically heterogenous and commits to an unwanted osteoprogenitor pathway when it experiences an abnormal mechanically stiff environment, compared to its native softer environment. A method is developed to measure the heterogeneity using nuclear shape, chromatin state, and CD73 marker. Heterogeneity is shown to be associated with a larger spread in the nuclear shape parameters and a smaller spread in the chromatin openness. Subsequently, intervention strategies are investigated to create a more homogeneous MSC population. Culturing MSCs on soft surfaces or inhibiting actomyosin on stiff surfaces can make them more homogeneous, while inhibiting YAP, Runx2, and actin polymerization helps maintain but does not fully homogenize them. This study offers insights for cell and tissue engineers, aiding in the design of optimal conditions and materials for MSC culture, ultimately enhancing their therapeutic potential.

Untoward immune effects of modern medication

Immune-related adverse events (irAEs) represent an increasingly concerning challenge in the assessment of biopharmaceutical products. In contrast to historically rare allergic reactions associated with small chemical drugs, contemporary biotherapeutics exhibit a significantly higher morbidity of irAEs, because of their complex structure and comprehensive mechanisms of action. While the immunogenicity of protein-based compounds is associated with the induction of anti-drug antibodies, the pathogenesis of irAEs in advanced biologics, such as cell and gene therapy, remains to be further delineated. In the current study, I present an updated profile regarding the untoward immune effects of medications, covering various material categories systematically, with the underlying mechanisms to inspire risk mitigation in biopharmaceutical development and application.

Umbilical cord-derived mesenchymal stem cell sheets transplanted subcutaneously enhance cell retention and survival more than dissociated stem cell injections

BACKGROUND

Human umbilical cord-derived mesenchymal stem cell (hUC-MSC) sheets have recently attracted attention as an alternative approach to injected cell suspensions for stem cell therapy. However, cell engraftment and cytokine expression levels between hUC-MSC sheets and their cell suspensions in vivo have not yet been compared. This study compares hUC-MSC in vivo engraftment efficacy and cytokine expression for both hUC-MSC sheets and cell suspensions.

METHODS

hUC-MSC sheets were prepared using temperature-responsive cell culture; two types of hUC-MSC suspensions were prepared, either by enzymatic treatment (trypsin) or by enzyme-free temperature reduction using temperature-responsive cell cultureware. hUC-MSC sheets and suspensions were transplanted subcutaneously into ICR mice through subcutaneous surgical placement and intravenous injection, respectively. hUC-MSC sheet engraftment after subcutaneous surgical transplantation was investigated by in vivo imaging while intravenously injected cell suspensions were analyzing using in vitro organ imaging. Cytokine levels in both transplant site tissues and blood were quantified by enzyme-linked immunosorbent assay.

RESULTS

After subcutaneous transplant, hUC-MSC sheets exhibited longer engraftment duration than hUC-MSC suspensions. This was attributed to extracellular matrix (ECM) and cell-cell junctions retained in sheets but enzymatically altered in suspensions. hUC-MSC suspensions harvested using enzyme-free temperature reduction exhibited relatively long engraftment duration after intravenous injection compared to suspensions prepared using trypsin, as enzyme-free harvest preserved cellular ECM. High HGF and TGF-β1 levels were observed in sheet-transplanted sites compared to hUC-MSC suspension sites. However, no differences in human cytokine levels in murine blood were detected, indicating that hUC-MSC sheets might exert local paracrine rather than endocrine effects.

CONCLUSIONS

hUC-MSC sheet transplantation could be a more effective cell therapeutic approach due to enhanced engraftment and secretion of therapeutic cytokines over injected hUC-MSC suspensions.

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

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