Minimal criteria for defining multipotent mesenchymal stromal cells. The International Society for Cellular Therapy position statement

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.

Nanofibrous Scaffolds' Ability to Induce Mesenchymal Stem Cell Differentiation for Soft Tissue Regenerative Applications

Mesenchymal stem cells (MSCs) have gained recognition as a highly versatile and promising cell source for repopulating bioengineered scaffolds due to their inherent capacity to differentiate into multiple cell types. However, MSC implantation techniques have often yielded inconsistent clinical results, underscoring the need for advanced approaches to enhance their therapeutic efficacy. Recent developments in three-dimensional (3D) bioengineered scaffolds have provided a significant breakthrough by closely mimicking the in vivo environment, addressing the limitations of traditional two-dimensional (2D) cell cultures. Among these, nanofibrous scaffolds have proven particularly effective, offering an optimal 3D framework, growth-permissive substrates, and the delivery of trophic factors crucial for MSC survival and regeneration. Furthermore, the selection of appropriate biomaterials can amplify the paracrine effects of MSCs, promoting both proliferation and targeted differentiation. The synergistic combination of MSCs with nanofibrous scaffolds has demonstrated remarkable potential in achieving repair, regeneration, and tissue-specific differentiation with enhanced safety and efficacy, paving the way for routine clinical applications. In this review, we examine the most recent studies (2013-2023) that explore the combined use of MSCs and nanofibrous scaffolds for differentiation into cardiogenic, epithelial, myogenic, tendon, and vascular cell lineages. Using PubMed, we identified and analyzed 275 relevant articles based on the search terms "Nanofibers", "Electrospinning", "Mesenchymal stem cells", and "Differentiation". This review highlights the critical advancements in the use of nanofibrous scaffolds as a platform for MSC differentiation and tissue regeneration. By summarizing key findings from the last decade, it provides valuable insights for researchers and clinicians aiming to optimize scaffold design, MSC integration, and translational applications. These insights could significantly influence future research directions and the development of more effective regenerative therapies.

Quality Control of Fetal Wharton's Jelly Mesenchymal Stem Cells-Derived Small Extracellular Vesicles

Background

Quality control (QC) is an important element in ensuring drug substances' safety, efficacy, and quality. The dosing regimen for sEVs can be in the form of protein concentration or the number of particles based on the results of a series of quality controls applied as in-process control.

Methods

Wharton's Jelly Mesenchymal Stem Cells (WJMSCs) were isolated from four independent umbilical cord samples and were characterized following the International Society for Cellular Therapy (ISCT) guidelines. Small extracellular vesicles (sEVs) were isolated separately from these four WJMSCs samples using the Tangential Flow Filtration (TFF) method and were characterized per Minimal Information for Studies of Extracellular Vesicles (MISEV2018) guidelines. Each isolated and concentrated sEV preparation was standardized and its purity was determined by the ratio of the number of particles to protein concentration.

Results

All the WJMSCs samples passed the Mesenchymal Stem Cells (MSCs) characterization QC tests. Qualitatively, EVs-positive markers (CD63 and TSG101) and intact bilipid membrane vesicles were detected in all the sEV preparations. Quantitatively, the protein and particle concentrations revealed that all the sEV preparations were "impure" with < 1.5 × 109 particles/µg protein. Albumin was co-isolated in all the sEV preparations.

Conclusion

In short, all characterized and standardized individual and pooled sEV preparations were deemed "impure" due to albumin co-isolation using the TFF method. For therapeutic development, it is essential to report protein and particle concentrations in EV preparations based on these QC results.

Cell-based therapies in preclinical models of necrotizing enterocolitis: a systematic review and meta-analysis

Necrotizing enterocolitis (NEC) remains an incurable gut complication of prematurity with significant morbidity and mortality. Cell therapies, including mesenchymal stromal cells (MSCs), may be a promising treatment given their anti-inflammatory and regenerative potential. We assessed the effect of MSCs and other cell therapies (not classified as MSCs) on incidence, severity, and mortality in preclinical models of NEC. Bibliographic and gray literature searches yielded 17 371 records with 107 full-text articles assessed and ultimately 16 studies were included. These studies featured only rodents NEC models via combination of hyperosmolar feeds, hypoxia, hypothermia, or lipopolysaccharides. Ten studies used interventions with MSCs. Only 2 met the minimal criteria to define MSCs proposed by the International Society for Cell & Gene Therapy (ISCT). The overall risk of bias was assessed as high partly due to paucity of data with important gaps in reporting, reinforcing the importance of rigorous research framework, appropriate cell-therapy and outcome reporting in preclinical research. A reduction in the incidence of NEC (odds ratio [OR] 0.32, 95% CI [0.17, 0.62]), severe NEC (OR 0.30, 95% CI [0.18, 0.50]), and mortality (OR 0.30, 95% CI [0.16, 0.55]) was noted with MSCs treatment, seemingly more pronounced for ISCT-defined (ISCT+) MSCs. Amniotic fluid stem cells, neural stem cells, and placenta stem cells also showed a reduction in these measures. Given their accessibility (ie, umbilical cord) and proven safety profile in extremely preterm infants, our analysis provides a foundation for considering MSCs as promising candidate that requires further evaluation for the treatment of NEC.

Bone Fillers with Balance Between Biocompatibility and Antimicrobial Properties

Millions of people request bone regeneration every year, and the market for bone grafting materials has a positive trend. The most used biomaterials applied to replace and regenerate bone are based on collagen and different types of ceramics in order to mimic natural bone matrix. However, there are a lot of implant-associated infections after surgery, or the implants are rejected because of reduced biocompatibility, and this is why the research into graft bone materials is still a challenge. This study aims to develop and characterize novel biomimetic bone fillers which have simultaneously both antimicrobial properties and biocompatibility with human bone marrow-derived mesenchymal stem cells (BMSCs). Type I collagen and calcium triphosphate in a ratio of 1:1 were used as a control, according to our previous studies, and ZnO, functionalized with different percentages of Satureja thymbra L. essential oils, was added as an antimicrobial, promoting bone growth, mineralization, and formation. The bone fillers were obtained by freeze-drying in spongious forms and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), water uptake, biodegradability over time, antimicrobial activity against Staphylococcus aureus and Escherichia coli and viability and proliferation of human BMSCs. The graft material showed a higher porosity with interconnected pores, gradual resorption over time and a balance between antimicrobial properties and biocompatibility and was chosen as an ideal bone filler.

Tumor-initiating and metastasis-initiating cells of clear-cell renal cell carcinoma

Clear-cell renal cell carcinoma (ccRCC) is the most common subtype of kidney malignancy. ccRCC is considered a major health concern worldwide because its numbers of incidences and deaths continue to rise and are predicted to continue rising in the foreseeable future. Therefore new strategy for early diagnosis and therapeutics for this disease is urgently needed. The discovery of cancer stem cells (CSCs) offers hope for early cancer detection and treatment. However, there has been no definitive identification of these cancer progenitors for ccRCC. A majority of ccRCC is characterized by the loss of the von Hippel-Lindau (VHL) tumor suppressor gene function. Recent advances in genome analyses of ccRCC indicate that in ccRCC, tumor-initiating cells (TICs) and metastasis-initiating cells (MICs) are two distinct groups of progenitors. MICs result from various genetic changes during subclonal evolution, while TICs reside in the stem of the ccRCC phylogenetic tree of clonal development. TICs likely originate from kidney tubule progenitor cells bearing VHL gene inactivation, including chromatin 3p loss. Recent studies also point to the importance of microenvironment reconstituted by the VHL-deficient kidney tubule cells in promoting ccRCC initiation and progression. These understandings should help define the progenitors of ccRCC and facilitate early detection and treatment of this disease.

Effect of Bio MTA plus & ProRoot MTA pulp capping materials on the regenerative properties of human dental pulp stem cells

The aim of the present study was to investigate the effects of the biological properties of hDPSCs exposed to Bio MTA+ & ProRoot MTA pulp capping materials on the proliferation and odontogenic differentiation of hDPSCs. Human dental pulp stem cells (hDPSCs) were isolated from impacted third molars. Extracts of Bio MTA + and ProRoot MTA were prepared at a 1:1 ratio. The effects of the extracts on hDPSCs cytotoxicity and proliferation were assessed via a CCK-8 assay. Annexin V expression was investigated to assess the effects of both materials on the induction of apoptosis. The effects of ProRoot MTA and Bio MTA + extraction media on the stemness properties of hDPSCs were assessed via real-time quantitative PCR, and the expression of odontogenic markers (RUNX2, DMP1 & DSSP) was analyzed via RT‒PCR Alizarin Red staining. Cells exposed to Bio MTA + had the greatest degree of proliferation. The results of Annexin V staining indicated that Bio MTA + caused the least amount of apoptosis. RUNX2, DMP1 and DSSP were highly expressed by Bio MTA + and indicated successful odontogenic differentiation. Compared with ProRoot MTA, Bio MTA + exhibited an exceptional level of cytocompatibility, as well as advantageous bioactivities, including the preservation of stemness and an increase in the proliferation capacity of hDPSCs. In addition, it demonstrated favorable bioactive properties by stimulating odontogenic differentiation. Bio MTA + offers significant advantages in terms of biocompatibility, bioactivity, and regenerative potential, making it an excellent choice for procedures aimed at preserving or regenerating dental pulp tissue. However, additional research is required to address the lack of in vivo validation, as replicating physiological conditions is crucial for accurately assessing clinical outcomes and comparing them with results obtained from in vitro experiments.

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.

The Potential Role of Adipose-Derived Stem Cells in Regeneration of Peripheral Nerves

Peripheral nerve injuries are common complications in surgical and dental practices, often resulting in functional deficiencies and reduced quality of life. Current treatment choices, such as autografts, have limitations, including donor site morbidity and suboptimal outcomes. Adipose-derived stem cells (ADSCs) have shown assuring regenerative potential due to their accessibility, ease of harvesting and propagation, and multipotent properties. This review investigates the therapeutic potential of ADSCs in peripheral nerve regeneration, focusing on their use in bioengineered nerve conduits and supportive microenvironments. The analysis is constructed on published case reports, organized reviews, and clinical trials from Phase I to Phase III that investigate ADSCs in managing nerve injuries, emphasizing both peripheral and orofacial applications. The findings highlight the advantages of ADSCs in promoting nerve regeneration, including their secretion of angiogenic and neurotrophic factors, support for cellular persistence, and supplementing scaffold-based tissue repair. The regenerative capabilities of ADSCs in peripheral nerve injuries offer a novel approach to augmenting nerve repair and functional recovery. The accessibility of adipose tissue and the minimally invasive nature of ADSC harvesting further encourage its prospective application as an autologous cell source in regenerative medicine. Future research is needed to ascertain standardized protocols and optimize clinical outcomes, paving the way for ADSCs to become a mainstay in nerve regeneration.

Amine-Functionalized Gellan Gum-Based Hydrogel Loaded with Adipose Stem Cell-Derived Small Extracellular Vesicles: An In Vitro Proof of Concept for Enhancing Diabetic Foot Ulcer Healing

Diabetic foot ulcers (DFUs) are chronic wounds and a common complication of diabetes. A promising strategy in the treatment of DFUs involves the use of stem cell derivatives, such as small extracellular vesicles (sEVs), which can enhance cell proliferation and reduce inflammation while avoiding immunogenic responses. In this study, we evaluated the ability of adipose mesenchymal stem cell- (ASC)-derived sEVs to enhance the proliferation of human fibroblasts, which play a crucial role in wound regenerative processes. To mimic the inflammatory environment of DFUs, fibroblasts were cultured into the gellan gum (GG) modified with ethylenediamine (EDA) hydrogel scaffolds loaded with ASC-derived sEVs, under pro-inflammatory cytokines. Our comparative analysis demonstrated that sEVs loaded in GG-EDA hydrogel improved fibroblast viability in pro-inflamed conditions while retaining the anti-inflammatory and immunomodulatory properties of their cells of origin. By modulating the gene expression profile of fibroblasts to promote cell proliferation, wound healing and re-epithelialization, our system presents a promising therapeutic strategy for DFU healing.

Effect of adipose-derived mesenchymal stem cells on the viability of the transverse rectus abdominis myocutaneous flap in rats

INTRODUCTION

The Transverse Rectus Abdominis Myocutaneous (TRAM) flap is used for breast reconstruction, but involves the risk of necrosis. Adipose tissue-derived mesenchymal Stem Cells (ADSCs) can be used to stimulate neovascularization and reduce the risk of TRAM flap necrosis.

AIM

Determine the effect of ADSCs on TRAM flap viability in rats.

METHODS

Twenty-four Wistar-EPM rats were distributed into three groups (n = 8). A right caudal pedicled TRAM flap was performed in all the animals and was the only procedure performed in Group TRAM. The additional procedures of intradermal injection of α-MEM culture medium and intradermal injection of α-MEM containing ADSCs labeled with a fluorescent marker were performed in Groups α-MEM and α-MEM-SC, respectively. The percentage of flap necrosis was determined, and the level of neovascularization and distribution of stem cells in the TRAM flap was assessed using immunohistochemical analysis and fluorescence microscopy, respectively.

RESULTS

The percentage of necrosis observed in Group α-MEM-SC was lower than that observed in Groups TRAM and α-MEM, namely 23.36 % vs. 50.42 % and 53.57 %, respectively (p < 0.05). In Zone IV of the flap, the number of vessels was greater in Group α-MEM-SC than in the other groups (p < 0.05). Multiple stem cells were observed in the four zones of the flap in Group α-MEM-SC. No stem cells were observed in Groups TRAM or α-MEM.

CONCLUSION

ADSCs increased TRAM flap viability and the number of vessels in Zone IV of the flap in rats.

Proteomic profiling of iPSC and tissue-derived MSC secretomes reveal a global signature of inflammatory licensing

Much of the therapeutic potential of mesenchymal stromal cells (MSCs) is underpinned by their secretome which varies significantly with source, donor and microenvironmental cues. Understanding these differences is essential to define the mechanisms of MSC-based tissue repair and optimise cell therapies. This study analysed the secretomes of bone-marrow (BM.MSCs), umbilical-cord (UC.MSCs), adipose-tissue (AT.MSCs) and clinical/commercial-grade induced pluripotent stem cell-derived MSCs (iMSCs), under resting and inflammatory licenced conditions. iMSCs recapitulated the inflammatory licensing process, validating their comparability to tissue-derived MSCs. Overall, resting secretomes were defined by extracellular matrix (ECM) and pro-regenerative proteins, while licensed secretomes were enriched in chemotactic and immunomodulatory proteins. iMSC and UC.MSC secretomes contained proteins indicating proliferative potential and telomere maintenance, whereas adult tissue-derived secretomes contained fibrotic and ECM-related proteins. The data and findings from this study will inform the optimum MSC source for particular applications and underpin further development of MSC therapies.

Umbilical Cord Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles Modulate Skin Matrix Synthesis and Pigmentation

Introduction

Research has unveiled the remarkable properties of extracellular vesicles derived from mesenchymal stromal cells (MSCs), particularly in promoting wound healing, aiding re-epithelialization, revitalizing aging skin, and inhibiting hyperpigmentation. However, investigations into the potential of small extracellular vesicles from umbilical cord-derived MSCs (UC-MSC-sEVs) in reducing scarring and preventing hyperpigmentation remain limited. Therefore, this study aims to evaluate the impact of UC-MSC-sEVs on the synthesis of the skin's extracellular matrix (ECM) and pigmentation using in vitro models.

Methods

The study investigated the impact of characterized UC-MSC-sEVs on various aspects including the proliferation, migration, antioxidant activity, and ECM gene expression of human dermal fibroblasts (HDF). Additionally, the effects of UC-MSC-sEVs on the proliferation, melanin content, and tyrosinase (TYR) activity of human melanoma cells (MNT-1) were examined. Furthermore, ex vivo models were employed to evaluate the skin permeation of PKH26-labelled UC-MSC-sEVs.

Results

The findings indicated that a high concentration of UC-MSC-sEVs positively influenced the proliferation of HDF. However, no changes in cell migration rate were observed. While the expressions of collagen type 1 and type 3 remained unaffected by UC-MSC-sEVs treatment, there were dose-dependent increases in the gene expressions of fibronectin, matrix metallopeptidase (MMP) 1, and MMP 3. Furthermore, UC-MSC-sEVs treatment did not impact the antioxidative superoxide dismutase (SOD) expression in HDF. Although UC-MSC-sEVs did not alter the proliferation of MNT-1 cells, it did result in a dose-dependent reduction in melanin synthesis without affecting TYR activity. However, when it was applied topically, UC-MSC-sEVs failed to penetrate the skin barrier and remained localized within the stratum corneum layer even after 18 hours.

Conclusion

These results highlight the potential of UC-MSC-sEVs in stimulating HDF proliferation, regulating ECM synthesis, and reducing melanin production. This demonstrates the promising application of UC-MSC-sEVs in medical aesthetics for benefits such as scar reduction, skin rejuvenation, and skin lightening.

Recent advances in mesenchymal stem cell therapy for multiple sclerosis: clinical applications and challenges

Multiple sclerosis (MS), a chronic autoimmune disorder of the central nervous system (CNS), is characterized by inflammation, demyelination, and neurodegeneration, leading to diverse clinical manifestations such as fatigue, sensory impairment, and cognitive dysfunction. Current pharmacological treatments primarily target immune modulation but fail to arrest disease progression or entirely reverse CNS damage. Mesenchymal stem cell (MSC) therapy offers a promising alternative, leveraging its immunomodulatory, neuroprotective, and regenerative capabilities. This review provides an in-depth analysis of MSC mechanisms of action, including immune system regulation, promotion of remyelination, and neuroregeneration. It examines preclinical studies and clinical trials evaluating the efficacy, safety, and limitations of MSC therapy in various MS phenotypes. Special attention is given to challenges such as delivery routes, dosing regimens, and integrating MSCs with conventional therapies. By highlighting advancements and ongoing challenges, this review underscores the potential of MSCs to revolutionize MS treatment, paving the way for personalized and combinatory therapeutic approaches.

Delphi-driven consensus definition for mesenchymal stromal cells and clinical reporting guidelines for mesenchymal stromal cell-based therapeutics

BACKGROUND AIMS

Despite promising results in pre-clinical studies, mesenchymal stromal cells (MSCs) face significant challenges in clinical translation. A scoping review by our group highlighted two key issues contributing to this gap: (i) lack of a clear and consensus definition for MSCs and (ii) under-reporting of critical parameters in MSC clinical studies. To address these issues, we conducted a modified Delphi study to establish and implement a consensus definition for MSCs and develop reporting guidelines for MSC clinical studies.

METHODS

A steering committee of 22 international experts, including stakeholders from different MSC research fields, participated in the three Delphi rounds. For the first round, to obtain a broad perspective, additional investigators recommended by the steering committee were invited to participate. The first two rounds consisted of online surveys, whereas the third round took the form of a virtual meeting. Participants were asked to rate a series of potential defining characteristics of MSCs and items for reporting guidelines. Consensus was defined as at least 80% of the participants rating the item in the same category of importance.

RESULTS

Eighty-seven international participants participated in the first round survey (spring 2023), 17 participants participated in the second online survey (fall 2023) and 15 participants participated in the final virtual consensus meeting (January 2024). For the MSC definition, 20 items were considered and nine reached consensus. Items included terminology (one item), cell marker expression (five items), tissue origin (one item), stemness (one item) and description of critical quality attributes (one item). For the reporting guidelines, with the 28 initial items and the additional items suggested during round 1, a total of 33 items to report were included. This included items on MSC intervention group and control (e.g., MSC product, dose and administration), MSC characteristics (e.g., MSC provenance, "fitness," viability and immune compatibility) and MSC culture conditions (e.g., oxygen environment, culture medium and use of serum).

CONCLUSIONS

By applying a Delphi method to establish a consensus definition for MSCs and reporting guidelines for MSC-based clinical trials, this work represents a significant advance in improving transparency and reproducibility in the conduct and reporting of MSC research.

The Effects of Hypoxia-Preconditioned Dental Stem Cell-Derived Secretome on Tissue Regeneration

Mesenchymal stroma cells derived from oral tissues are known as dental stem cells (DSCs). Owing to their unique therapeutic niche and clinical accessibility, DSCs serve as a promising treatment option for bone defects and oral tissue regeneration. DSCs exist in a hypoxic microenvironment in vivo, which is far lower than the current 20% oxygen concentration used in in vitro culture. It has been widely reported that the application of an oxygen concentration less than 5% in the culture of DSCs is beneficial for preserving stemness and promoting proliferation, migration, and paracrine activity. The paracrine function of DSCs involves the secretome, which includes conditioned media (CM) and soluble bioactive molecules, as well as extracellular vesicles extracted from CM. Hypoxia can play a role in immunomodulation and angiogenesis by altering the protein or nucleic acid components in the secretory group, which enhances the therapeutic potential of DSCs. This review summarizes the biological characteristics of DSCs, the influence of hypoxia on DSCs, the impact of hypoxia on the secretory group of DSCs, and the latest progress on the use of DSCs secretory group in tissue regeneration based on hypoxia pretreatment. We highlighted the multifunctional biological effect of hypoxia culture on tissue regeneration and provided a summary of the current mechanism of hypoxia in the pretreatment of DSCs.

Innovative approaches to tissue engineering: Utilizing decellularized extracellular matrix hydrogels for mesenchymal stem cell transport

In recent years, the realm of tissue regeneration experienced significant advancements, leading to the development of innovative therapeutic agents. The systemic delivery of mesenchymal stem cells (MSCs) emerged as a promising strategy for promoting tissue regeneration. However, this approach is hindered by hurdles such as poor cell survival, limited cell propagation, and inadequate cell integration. Decellularized extracellular matrix (dECM) hydrogel serves as an innovative carrier that protects MSCs from the detrimental effects of the hostile microenvironment, facilitates their localization and retention at the injection site, and preserves their viability. Regarding its low immunogenicity, low cytotoxicity, high biocompatibility, and its ability to mimic natural extracellular matrix (ECM), this natural hydrogel offers a new avenue for systemic delivery of MSCs. This review digs into the properties of dECM hydrogels (dECMHs), the methods employed for decellularization and the utilization of dECMH as carriers for various types of MSCs for tissue regeneration purposes. This review also sheds light on the benefits of hybrid hydrogels composed of dECMH and other components such as proteins and polysaccharides. By addressing the limitations of conventional hydrogels and enhancing efficacy of cell therapy, dECMH opens new pathways for the future of tissue regeneration.

Efficacy of a single dose of cryopreserved human umbilical cord mesenchymal stromal cells for the treatment of knee osteoarthritis:a randomized, controlled, double-blind pilot study

BACKGROUND

Knee osteoarthritis (OA) is the most prevalent degenerative musculoskeletal disorder, which is particularly common in older population. While conventional treatments have limited effectiveness, the development of more effective therapeutic strategies is necessary to address this primary source of pain and disability. Umbilical cord mesenchymal stromal cells (UC-MSCs) offer a promising therapeutic approach for treating knee OA.

AIM

This randomized, prospective, double-blind and controlled pilot study was carried out to evaluate and compare the safety and therapeutic efficacy of a single intra-articular injection of a standardized product CellistemOA (5 × 106 ± 5 × 105 UC-MSCs), vs. triamcinolone (a synthetic corticosteroid) (10 mg/mL) in thirty patients with symptomatic knee OA (Kellgren-Lawrence grade II or III).

METHODS

The outcomes included changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores based on a Likert scale, numerical rating score (NRS) for pain, Magnetic Resonance Imaging (MRI), and quality of life (SF-36 questionnaire), from baseline and throughout 12-months of follow-up.

RESULTS

Patients treated with CellistemOA showed significant improvement in WOMAC score (including the three subscale scores (pain, stiffness and function), NRS in pain, and SF-36 profile from baseline to 12 months (p < 0.05) compared to the triamcinolone group, and no severe adverse events were reported. There were no significant differences in MRI WORMS scores between the two groups. However, patients who received the cellular treatment experienced a significant improvement in their SF-36 profile (p < 0.05).

CONCLUSIONS

This pilot study revealed that a single dose of CellistemOA is safe and superior to the active comparator in knee OA at 1-year of follow-up, making it a compelling therapeutic alternative to treat symptomatic OA patients.

High paracrine activity of hADSCs cartilage microtissues inhibits extracellular matrix degradation and promotes cartilage regeneration

Due to its unique structure, articular cartilage has limited self-repair capacity. Microtissues are tiny tissue clusters that can mimic the function of target organs or tissues. Using cells alone for microtissue construction often results in the formation of necrotic cores. However, the extracellular matrix (ECM) of native cartilage can provide structural support and is an ideal source of microcarriers. Autologous adipose-derived mesenchymal stem cells (ADSCs) and bone marrow mesenchymal stem cells (BMSCs) are widely used in cartilage tissue engineering. In this study, we fabricated microcarriers and compared the behavior of two homologous cell types in the microcarrier environment. The microcarrier environment highlighted the advantages of ADSCs and promoted the proliferation and migration of these cells. Then, ADSCs microtissues (ADSCs-MT) and BMSCs microtissues (BMSCs-MT) were fabricated using a three-dimensional dynamic culture system. In vitro and in vivo experiments verified that the cartilage regeneration ability of ADSCs-MT was significantly superior to that of BMSCs-MT. Transcriptomics revealed that ADSCs-MT showed significantly lower expression levels of ECM degradation, osteogenesis, and fibrocartilage markers. Finally, the protective effect of microtissues on inflammatory chondrocytes was validated. Overall, the ADSCs-MT constructed in this study achieved excellent cartilage regeneration and could be promising for the autologous application of cartilage microtissues.

Single-Cell Transcriptome Decoding Umbilical Cord-Derived Mesenchymal Stem Cell Heterogeneity Reveals a Unique IL1R1HighPDGFRAHigh Ultroser-G-MSC With Osteogenesis and Chondrogenesis Signatures

The heterogeneity of human umbilical cord mesenchymal stem cells (hUC-MSCs) is culturing-dependent, resulting in functional non-uniformness. To achieve the best clinical benefit, a comprehensive understanding of the origin of the heterogeneity in different culture systems can identify functional subgroups to direct the precise application of hUC-MSCs. Here, we create a single-cell transcriptome atlas of hUC-MSC in different culture systems for the identification of a subgroup of Ultroser-G-MSCs with high osteogenic and chondrogenic potentials featured by high expressions of IL1R1 and PDGFRA. Further experimental validations surprisingly reveal that IL1R1highPDGFRAhigh Ultroser-G-MSCs possess advantages over "traditional" hUC-MSCs in the treatments of modeled osteoarthritis, leading to a cell-cell communication network centered in Clusters 0 and 2. Moreover, we found that Wnt5 signaling is the key pathway for the dynamic transformation of osteogenic and chondrogenic phenotypes in hUC-MSC. Overall, the present study paves the way for the clarification of heterogenetic nature of hUC-MSC in different culture systems for the selection of optimal MSC types to achieve the precision on clinical treatments.

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

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

Mesenchymal stem cell-derived protein extract induces periodontal regeneration

BACKGROUND

Periodontal disease is characterized by chronic inflammation and destruction of supporting periodontal tissues, ultimately leading to tooth loss. In recent years, "cell-free treatment" without stem cell transplantation has attracted considerable attention for tissue regeneration. This study investigated the effects of extracts of mesenchymal stem cells (MSC-extract) and their protein components (MSC-protein) on the proliferation and migration of periodontal ligament (PDL) cells and whether MSC-protein can induce periodontal regeneration.

METHODS

MSC-extract and MSC-protein were obtained by subjecting mesenchymal stem cells (MSCs) to freeze-thaw cycles and acetone precipitation. Cell proliferation was examined using a WST-8 assay and Ki67 immunostaining, and cell migration was examined using Boyden chambers. The MSC-protein content was analyzed using liquid chromatography-mass spectrometry, protein arrays, and enzyme-linked immunosorbent assays (ELISAs). Gene expression in MSC-protein-treated PDL cells was examined using RNA-sequencing and Gene Ontology analyses. The regenerative potential of MSC-protein was examined using micro-computer tomography (CT) and histological analyses after transplantation into a rat periodontal defect model.

RESULTS

MSC-extract and MSC-protein promoted the proliferation and migration of PDL cells. Protein array and ELISA revealed that MSC-protein contained high concentrations of basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF). Exogenous bFGF promoted the proliferation and migration of PDL cells. Furthermore, the transplantation of MSC-protein enhanced periodontal tissue regeneration with the formation of new alveolar bone and PDLs.

CONCLUSIONS

These results indicate that the MSC-protein promotes the proliferation and migration of PDL cells and induces significant periodontal tissue regeneration, suggesting that the MSC-protein could be used as a new cell-free treatment for periodontal disease.

Development of a natural rubber latex-based biodevice with mesenchymal stem cells as a potential treatment for skeletal muscle regeneration in gestational diabetes-induced myopathy

Women with gestational diabetes mellitus show a high risk of developing Gestational Diabetes Induced Myopathy (GDiM). GDiM is characterized by significant pelvic floor skeletal muscle atrophy and urinary incontinence. This study aimed to develop a natural rubber latex (NRL) based biodevice with mesenchymal/stromal stem cells (MSCs) for skeletal muscle regeneration for women with GDiM. NRL showed porosity, roughness, biocompatibility, and bioactivity. MSCs adhesion on the NRL scaffold surface was assessed by scanning electron microscopy (SEM), confocal microscopy, and zymography. The scaffold's physicochemical and biological properties were carried out by Fourier transform infrared spectroscopy (FTIR), swelling and degradation studies, hemolytic activity, and antioxidant activity (AA), using Electronic Paramagnetic Resonance (EPR). MSCs in culture expressed CD90, adhered to plastic, differentiated, and produced fibroblast colonies. A high rate of cell proliferation was seen in MSCs on the NRL scaffold. FTIR analysis confirmed protein structures and polyisoprene in the scaffold. Swelling and degradation showed low water uptake and weight loss. Furthermore, NRL presented a hemolytic rate of 2.90 ± 0.26 % for 24 h, and EPR revealed the scaffold's strong AA. The generated biodevice has potential for muscle regeneration and may be useful as a therapeutic option for skeletal muscle disorders in GDiM or urinary incontinence.

Aging and cell expansion enhance microRNA diversity in small extracellular vesicles produced from human adipose-derived stem cells

Adipose-derived stem cells (ASCs) and their small extracellular vesicles (sEVs) hold significant potential for regenerative medicine due to their tissue repair capabilities. The microRNA (miRNA) content in sEVs varies depending on ASC status; however, the effects of aging and cell passage on miRNA profiles remain unclear. In this study, we examined the effects of donor age and cell expansion on ASC characteristics and transcriptome using ASCs obtained from three young and three old donors. Cell expansion significantly impaired stem cell properties, notably reducing proliferation and differentiation capacities. In contrast, donor age had minimal effects on ASCs. RNA sequencing (RNA-seq) revealed differences in gene expression related to stemness, phagocytosis, and metabolic processes influenced by cell expansion. To investigate miRNA variability, we performed small RNA-seq on sEVs collected from ASCs of all six donors. The miRNA profiles were influenced by donor age and cell passage. Interestingly, functional enrichment analysis indicated that advanced donor age and increased cell passage may enhance the production of miRNAs associated with organ development through various pathways. These findings suggest that donor age and cell expansion differentially influence ASC characteristics and sEV miRNA content, highlighting the need for disease-specific conditioning of ASCs to optimize the therapeutic effects of sEVs in clinical applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-024-00675-6.

Matrigel-encapsulated articular cartilage derived fibronectin adhesion assay derived chondroprogenitors for enhanced chondrogenic differentiation: An in vitro evaluation

PURPOSE

In cartilage research, three-dimensional (3D) culture models are pivotal for assessing chondrogenic differentiation potential. Standard pellet cultures, despite their utility, pose challenges like uneven differentiation and handling difficulties. This study explores the use of Matrigel, an extracellular matrix-based hydrogel, to encapsulate fibronectin adhesion assay-derived chondroprogenitors (FAA-CPs) and evaluate their chondrogenic differentiation potential.

METHODS

FAA-CPs, isolated from human articular cartilage and expanded to passage 2, were either polymerized in Matrigel or cultured as standard pellets. Both groups underwent chondrogenic differentiation for 28 days and osteogenic differentiation for 21 days. Comprehensive analyses included histological staining, gene expression (SOX-9, ACAN, COL2A1 for chondrogenesis; COL1A1, RUNX2, COL10A1 for osteogenesis), and biochemical assays for glycosaminoglycans (GAG) and Collagen type II.

RESULTS

The results demonstrated that Matrigel-encapsulated FAA-CPs achieved greater GAG accumulation, as evidenced by enhanced Alcian Blue and Safranin O staining, compared to standard pellets. However, the Collagen type II deposition, both histologically and quantitatively, was reduced in Matrigel constructs. Gene expression analysis showed no significant differences in key chondrogenic and osteogenic markers between the two groups. Despite improved handling and GAG deposition, Matrigel did not enhance uniform chondrogenic differentiation nor offer significant benefits for osteogenic differentiation, showing comparable hypertrophic markers to the standard method.

CONCLUSION

While Matrigel encapsulation offers advantages in handling and enhances GAG accumulation quantitatively, these benefits were not reflected in staining results. Furthermore, Matrigel did not significantly outperform standard pellet cultures in chondrogenic or osteogenic differentiation. These findings suggest a need for further refinement and in vivo validation.

Decidual stromal cells: fibroblasts specialized in immunoregulation during pregnancy

Decidual stromal cells (DSCs) are involved in immunoregulatory mechanisms that prevent fetal rejection by the mammalian maternal immune system. Recent studies using single-cell RNA sequencing demonstrated the existence of different types of human and mouse DSCs, highlighting corresponding differentiation (decidualization) pathways, and suggesting their involvement in the immune response during normal and pathological pregnancy. DSCs may be considered tissue-specialized fibroblasts because both DSCs and fibroblasts share phenotypic and functional similarities in immunologically challenged tissues, especially in terms of their immune functions. Indeed, fibroblasts can setup, support, and suppress immune responses and these functions are also performed by DSCs. Moreover, fibroblasts and DSCs can induce ectopic foci as tertiary lymphoid structures (TLSs), and endometriosis, respectively. Thus, understanding DSC immunoregulatory functions is of timely relevance.

The effect of exosomes from canine bone mesenchymal stem cells on IL-1β-mediated inflammatory responses in chondrocytes

Osteoarthritis is a degenerative disease of cartilage, and exosome derived from mesenchymal stem cells (MSCs) are considered promising for treating inflammatory musculoskeletal disorders, although their mechanisms are not fully understood. This study aimed to investigate the effects of exosomes derived from canine bone marrow mesenchymal stem cells (cBMSCs-Exos) on the expression of inflammatory factors and genes related cartilage matrix metabolism in IL-1β-induced canine chondrocytes. Canine BMSCs were isolated and characterized for surface markers and trilineage differentiation. Exosomes were then extracted and performed surface labeling detection. Canine chondrocytes were exposed to IL-1β to mimic osteoarthritis in vitro. Subsequently, the chondrocytes were treated with exosomes from BMSCs, and the expression levels of related genes and IL-6 protein were assessed. The mesenchymal stem cells isolated from bone marrow and cultured exhibited positive CD44 and CD90, negative expression of CD45 and HLA, and demonstrated potential to differentiate into adipocytes, osteoblasts and chondrocytes. Exosomes from BMSCs exhibited positivity expression of CD9, CD63 and CD81. Treatment with exosomes significantly reduced IL-6 and TNF-α mRNA levels induced by IL-1β, as well as IL-6 protein expression. Additionally, a significant decrease was observed in the mRNA levels catabolic marker genes MMP-13, ADAMTS-5, and COX2. Conversely, there was a significant increase in the mRNA levels of anti-inflammatory cytokines IL-4, IL-10, and anabolic marker genes, such as COL2A1, ACAN, and SOX9. cBMSCs-Exos play a vital role in cartilage protection by suppressing the expression of pro-inflammatory and anabolic genes while simultaneously enhancing the expression of genes involved in synthesis metabolism.

Automated Manufacturing Processes and Platforms for Large-scale Production of Clinical-grade Mesenchymal Stem/ Stromal Cells

Mesenchymal stem/stromal cells (MSCs) hold immense potential for regenerative medicine due to their remarkable regenerative and immunomodulatory properties. However, their therapeutic application requires large-scale production under stringent regulatory standards and Good Manufacturing Practice (GMP) guidelines, presenting significant challenges. This review comprehensively evaluates automated manufacturing processes and platforms for the scalable production of clinical-grade MSCs. Various large-scale culture vessels, including multilayer flasks and bioreactors, are analyzed for their efficacy in MSCs expansion. Furthermore, automated MSCs production platforms, such as Quantum® Cell Expansion System, CliniMACS Prodigy®, NANT001/ XL, CellQualia™, Cocoon® Platform, and Xuri™ Cell Expansion System W25 are reviewed and compared as well. We also underscore the importance of optimizing culture media specifically emphasizing the shift from fetal bovine serum to humanized or serum-free alternatives to meet GMP standards. Moreover, advances in alternative cryopreservation methods and controlled-rate freezing systems, that offer promising improvements in MSCs preservation, are discussed as well. In conclusion, advancing automated manufacturing processes and platforms is essential for realizing the full potential of MSCs-based regenerative medicine and accomplishing the increasing demand for cell-based therapies. Collaborative initiatives involving industry, academia, and regulatory bodies are emphasized to accelerate the translation of MSCs-based therapies into clinical practice.

Nerve Regeneration Through Differentiation of Endometrial-Derived Mesenchymal Stem Cells into Nerve-Like Cells Using Polyacrylonitrile/Chitosan Conduit and Berberine in a Rat Sciatic Nerve Injury Model

Nervous injuries are common in humans. One of the most advanced treatment methods is neural tissue engineering. This research aims to utilize nerve-like cells (NLCs) derived from endometrial mesenchymal stem cells (EnMSCs) on a polyacrylonitrile/chitosan (PAN/CS) scaffold, along with berberine, for the reconstruction of a rat sciatic nerve injury model. In this experimental study, EnMSCs were obtained through enzymatic digestion and identified using flow cytometry and their differentiation into adipocyte and osteoblast. PAN nanofiber scaffolds were produced through electrospinning, and EnMSCs were neurally differentiated on these scaffolds for grafting into an animal model. The expression of Nestin, Map-2, Tuj-1, and NF genes in NLCs was confirmed through RT-PCR and immunocytochemistry. Twenty-five adult male rats were used in this study, divided into 5 groups: (1) Scaffold/Cells/Berberine, (2) Scaffold/Cells, (3) Scaffold, (4) Berberine, and (5) Control. The animals were maintained for 8 weeks, and their sciatic nerve function (SFI) was assessed. Additionally, histological examinations were performed using hematoxylin/eosin, luxol fast blue staining, and immunohistochemistry. According to the results, extraction, identification, and differentiation of EnMSCs and fabrication of PAN conduit and its transplantation were successfully performed. The best behavioral performance and histology were observed in the Scaffold/Cells/Berberine group. The SFI test results were -24.08 for the Scaffold/Cells/Berberine group and -39.27 for the control group. The nerve diameter in these two groups was 591 µm and 80 µm, respectively, and the percentage of new nerve formation was 18.5% in the Scaffold/Cells/Berberine group and 0.2% in the control group. The immunohistochemistry results demonstrated that the intensity of the green color was higher in the groups with cells compared to the groups without cells. Furthermore, in the luxol staining results, all groups showed a significant improvement compared to the control group. In the Scaffold/Cells/Berberine group, fibers, and axons appeared denser, more organized, and displayed a higher intensity of blue staining. According to the results of this study, EnMSCs demonstrated efficient differentiation into NLCs. With the assistance of PAN/CS scaffolds and simultaneous administration of berberine, EnMSCs have the potential for nerve regeneration and recovery from sciatic nerve injury in the rat animal model.

State of the Art in the Standardization of Stromal Vascular Fraction Processing

Stromal Vascular Fraction (SVF) has gained significant attention in clinical applications due to its regenerative and anti-inflammatory properties. Initially identified decades ago, SVF is derived from adipose tissue and has been increasingly utilized in a variety of therapeutic settings. The isolation and processing protocols for SVF have evolved substantially, particularly after its classification as an Advanced Therapy Medicinal Product (ATMP), which mandates adherence to Good Manufacturing Practices to ensure sterility and product quality. Despite the progress, few studies over the last decade have focused on the standardization of SVF processing. Recent advances, driven by the potential of SVF and its derived products such as Adipose-derived Stem Cells, have prompted the development of improved isolation strategies aimed at enhancing their therapeutic and regenerative efficacy. Notable progress includes the advent of automated processing systems, which reduce technical errors, minimize variability, and improve reproducibility across laboratories. These developments, along with the establishment of more precise protocols and guidelines, have enhanced the consistency and clinical applicability of SVF-based therapies. This review discusses the key aspects of SVF isolation and processing, highlighting the efforts to standardize the procedure and ensure the reliability of SVF products for clinical use.

Bone Marrow Mesenchymal Stem Cells-Derived Exosomes Inhibit Apoptosis of Pulmonary Microvascular Endothelial Cells in COPD Mice Through miR-30b/Wnt5a Pathway

Background

Bone marrow mesenchymal stem cells (BMSCs)-derived exosomes are rich in a variety of active substances, including microRNA (miR) and have shown powerful therapeutic effects to ameliorate cell injury and diseases. However, the role of BMSCs-derived exosomes on chronic obstructive pulmonary disease (COPD) has been poorly studied. In addition, pulmonary microvascular endothelial cells (PMVECs) apoptosis contributes to the onset of COPD. Inhibition of PMVECs apoptosis can reverse COPD changes. Therefore, the aim of this study was to explore the role of BMSCs-derived exosomes in the apoptosis of PMVECs in COPD and to investigate the potential mechanisms.

Methods

We isolated and characterized normal mouse BMSCs-derived exosomes and PMVECs. We performed miR sequencing of BMSCs-derived exosomes. We transfected PMVECs with the miR-30b mimic and Wnt5a overexpression plasmid to assess the underlying mechanisms. Cigarette smoke extract (CSE)-induced COPD mice were treated with exosomes and HBLV-mmu-miR-30b via intratracheal instillation. Finally, we determined the expression of miR-30b and Wnt5a in tissues from patients with COPD.

Results

BMSCs-derived exosomes could significantly reduce apoptosis of CSE-induced PMVECs and increase the expression of miR-30b (p<0.05). Based on miR sequencing, miR-30b was highly enriched in BMSCs-derived exosomes. The knockdown of miR-30b in BMSCs-derived exosomes could increase the apoptosis of CSE-induced PMVECs (p<0.05). miR-30b overexpression significantly reduced apoptosis and repressed Wnt5a protein expression in CSE-induced PMVECs (p<0.05). Furthermore, Wnt5a overexpression reversed the anti-apoptotic effect of miR-30b on CSE-induced PMVECs (p<0.05). In addition, compared with the COPD group, treatment with BMSCs-derived exosomes and miR-30b overexpression could alleviate emphysema changes, decrease the mean linear intercept and alveolar destructive index, reduce apoptosis, increase the expression of miR-30b, and decrease the expression of Wnt5a in lung tissue (p<0.05). Finally, miR-30b expression was decreased in patients with COPD, while Wnt5a expression was increased in these patients (p<0.05).

Conclusion

BMSCs-derived exosomes could improve the damage of COPD perhaps by delivering miR-30b. miR-30b could reduce apoptosis of CSE-induced PMVECs by targeting Wnt5a.

Therapeutic potential of mesenchymal stem cells for fungal infections: mechanisms, applications, and challenges

As a particularly serious condition in immunocompromised patients, fungal infections (FIs) have increasingly become a public health problem worldwide. Mesenchymal stem cells (MSCs), characterized by multilineage differentiation potential and immunomodulatory properties, are considered an emerging strategy for the treatment of FIs. In this study, the therapeutic potential of MSCs for FIs was reviewed, including their roles played by secreting antimicrobial peptides, regulating immune responses, and promoting tissue repair. Meanwhile, the status of research on MSCs in FIs and the controversies were also discussed. However, the application of MSCs still faces numerous challenges, such as the heterogeneity of cell sources, long-term safety, and feasibility of large-scale production. By analyzing the latest study results, this review intends to offer theoretical support for the application of MSCs in FI treatment and further research.

A study on the production of extracellular vesicles derived from novel immortalized human placental mesenchymal stromal cells

Extracellular vesicles (EVs) are not only involved in cell-to-cell communications but have other functions as "garbage bags", as bringing nutrients to cells, and as inducing mineral during bone formation and ectopic calcification. These minuscule entities significantly contribute to the regulation of bodily functions. However, the clinical application of EVs faces challenges due to limited production yield and targeting efficiency. In our study, we propose a method for efficiently harvesting EVs utilizing simian virus 40 large T antigen (SV40LT) immortalized human placental chorionic mesenchymal stromal cells (CMSCs). We investigated immortalized placental chorionic mesenchymal stromal cells (imCMSCs), a stromal cell line that surpasses the growth limitations of primary passage cells while retaining phenotypic characteristics and differentiation potential. This development offers the prospect of a consistent, uniform source of EVs, which is essential for regenerative medicine. Our findings indicate that the immortalization process preserves the particle size, quantity and surface marker profiles of EVs, providing a possible approach to produce high-yield EVs suitable for disease diagnosis and treatment.

Lyophilized human platelet lysate: manufacturing, quality control, and application

Background

A significant number of platelet concentrates (PCs) is discarded daily in blood banks due to limited shelf life. Human platelet lysate (HPL), derived from expired PCs, has gained attention as an ethical and sustainable cell culture media supplement in biomedical research and cell therapy production. However, HPL is subject to decisive disadvantages such as batch differences and lack of storage stability. To overcome these limitations and to enhance the applicability of HPL, we developed an HPL manufacturing protocol including a lyophilization process. The aim of this study was to investigate the influence of HPL lyophilization on parameters of quality control, including growth factor concentrations and the culture of human mesenchymal stromal cells (hMSCs).

Methods

We performed a paired comparison of six batches of HPL and lyophilized HPL (L-HPL) regarding the quality parameters pH, total protein, osmolality, sodium, potassium and chloride concentration. Concentrations of 11 growth factors and cytokines were compared between HPL and L-HPL. Additionally, we determined cell yield, proliferation capacity, viability and trilineage differentiation potential of hMSCs following expansion in HPL- and L-HPL-supplemented cell culture media.

Results

Quantification of the quality parameters revealed non-altered pH, osmolality and potassium concentrations and slightly lower total protein, sodium and chloride concentrations of L-HPL compared to HPL. Growth factor and cytokine concentrations did not differ between HPL and L-HPL. Cell yield, division cycles and viability of hMSCs cultured in either HPL- or L-HPL-containing media were comparable. Cells differentiated in medium containing L-HPL showed a slightly higher capacity for osteogenic differentiation, while adipogenic differentiation and chondrogenic differentiation potentials remained unchanged.

Conclusion

We successfully developed a method to produce well-applicable L-HPL. The comparison of L-HPL with HPL did not reveal any relevant differences regarding quality control parameters of routine testing, growth factor concentrations and hMSC functionality, demonstrating the suitability of L-HPL as a cell culture supplement. These results emphasize the potential of L-HPL as a sustainable and ethical alternative to animal-derived serum products in biomedical research and drug development.

Regulatory Immune Cell-derived Exosomes: Modes of Action and Therapeutic Potential in Transplantation

Reduced dependence on antirejection agents, improved long-term allograft survival, and induction of operational tolerance remain major unmet needs in organ transplantation due to the limitations of current immunosuppressive therapies. To address this challenge, investigators are exploring the therapeutic potential of adoptively transferred host- or donor-derived regulatory immune cells. Extracellular vesicles of endosomal origin (exosomes) secreted by these cells seem to be important contributors to their immunoregulatory properties. Twenty years ago, it was first reported that donor-derived exosomes could extend the survival of transplanted organs in rodents. Recent studies have revealed that regulatory immune cells, such as regulatory myeloid cells (dendritic cells, macrophages, or myeloid-derived suppressor cells), regulatory T cells, or mesenchymal stem/stromal cells can suppress graft rejection via exosomes that express a cargo of immunosuppressive molecules. These include cell surface molecules that interact with adaptive immune cell receptors, immunoregulatory enzymes, and micro- and long noncoding RNAs that can regulate inflammatory gene expression via posttranscriptional changes and promote tolerance through promotion of regulatory T cells. This overview analyzes the diverse molecules and mechanisms that enable regulatory immune cell-derived exosomes to modulate alloimmunity and promote experimental transplant tolerance. We also discuss the potential benefits and limitations of their application as therapeutic entities in organ transplantation.

Regional Gene Therapy for Bone Tissue Engineering: A Current Concepts Review

The management of segmental bone defects presents a complex reconstruction challenge for orthopedic surgeons. Current treatment options are limited by efficacy across the spectrum of injury, morbidity, and cost. Regional gene therapy is a promising tissue engineering strategy for bone repair, as it allows for local implantation of nucleic acids or genetically modified cells to direct specific protein expression. In cell-based gene therapy approaches, a variety of different cell types have been described including mesenchymal stem cells (MSCs) derived from multiple sources-bone marrow, adipose, skeletal muscle, and umbilical cord tissue, among others. MSCs, in particular, have been well studied, as they serve as a source of osteoprogenitor cells in addition to providing a vehicle for transgene delivery. Furthermore, MSCs possess immunomodulatory properties, which may support the development of an allogeneic "off-the-shelf" gene therapy product. Identifying an optimal cell type is paramount to the successful clinical translation of cell-based gene therapy approaches. Here, we review current strategies for the management of segmental bone loss in orthopedic surgery, including bone grafting, bone graft substitutes, and operative techniques. We also highlight regional gene therapy as a tissue engineering strategy for bone repair, with a focus on cell types and cell sources suitable for this application.

Differentiation of stem cells into chondrocytes and their potential clinical application in cartilage regeneration

Cartilage diseases and injuries are considered difficult to treat owing to the low regenerative capacity of this tissue. Using stem cells (SCs) is one of the potential methods of treating cartilage defects and creating functional cartilage models for transplants. Their ability to proliferate and to generate functional chondrocytes, a natural tissue environment, and extracellular cartilage matrix, makes SCs a new opportunity for patients with articular injuries or incurable diseases, such as osteoarthritis (OA). The review summarizes the most important scientific reports on biology and mechanisms of SC-derived chondrogenesis and sources of SCs for chondrogenic purposes. Additionally, it focuses on the genetic mechanisms, microRNA (miRNA) regulation, and epigenetic processes steering the chondrogenic differentiation of SCs. It also describes the attempts to create functional cartilage with tissue engineering using growth factors and scaffolds. Finally, it presents the challenges that researchers will have to face in the future to effectuate SC differentiation methods into clinical practice for treating cartilage diseases.

Characterization and Proteomic Profiling of Hepatocyte-like Cells Derived from Human Wharton's Jelly Mesenchymal Stromal Cells: De Novo Expression of Liver-Specific Enzymes

End-stage liver disease (ESLD), affecting millions worldwide, represents a challenging issue for clinical research and global public health. Liver transplantation is the gold standard therapeutic approach but shows some drawbacks. Hepatocyte transplantation could be a reliable alternative for patient treatment. Mesenchymal stromal cells derived from Wharton's jelly of the umbilical cord (WJ-MSCs) can differentiate into hepatocyte-like cells (HLCs) and show immunomodulatory functions. Due to the increasing demand for fully characterized cell therapy vehicles warranting both the safety and efficacy of treatments, in this work, we extensively characterized WJ-MSCs before and after the application of a hepatocyte-directed differentiation protocol. HLCs exhibited a morphology resembling that of hepatocytes, expressed early and late hepatic markers (α-fetoprotein, albumin, CK18, HNF4-α), and acquired hepatic functions (glycogen synthesis, xenobiotics detoxification), as also revealed by the shotgun proteomics approach. HLCs maintained the same pattern of immunomodulatory molecule expression and mesenchymal markers, other than displaying specific enzymes, suggesting these cells as promising candidates for cellular therapy of ESLD. Our work shed new light on the basic biology of HLCs, suggesting new therapeutic approaches to treat ESLD.

Investigation of Angiogenic Potential in CD146-Positive Stem Cells Derived from Human Exfoliated Deciduous Teeth

This study aimed to evaluate the effects of CD146, a surface antigen of mesenchymal stem cells from human exfoliated deciduous teeth (SHEDs), on angiogenic potential. SHEDs were isolated from patients' deciduous teeth and sorted into CD146-positive (CD146 + SHED) and CD146-negative (CD146 - SHED) populations. Three groups-non-sorted SHED, CD146 + SHED, and CD146 - SHED-were compared. Angiogenic potential was assessed by co-culturing each group with human umbilical vein endothelial cells (HUVECs) and evaluating lumen formation using an endothelial tube formation assay. The gene and protein expression levels of angiogenic markers, including vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), cluster of differentiation 31 (CD31), and basic fibroblast growth factor (bFGF), were analyzed using a real-time polymerase chain reaction and enzyme-linked immunosorbent assay. The tube formation assay revealed significantly enhanced angiogenic potential in CD146 + SHED and non-sorted SHED compared to CD146 - SHED. The gene and protein expression levels of VEGF, VEGFR2, CD31, and bFGF were significantly upregulated in CD146 + SHED and non-sorted SHED, highlighting superior angiogenic capabilities in CD146 + SHED. CD146 + SHED demonstrated enhanced angiogenic potential compared to CD146 - SHED, supporting their use in regenerative therapies targeting angiogenesis.

PIK3R3 regulates differentiation and senescence of periodontal ligament stem cells and mitigates age-related alveolar bone loss by modulating FOXO1 expression

INTRODUCTION

Periodontal diseases are prevalent among middle-aged and elderly individuals. There's still no satisfactory solution for tooth loss caused by periodontal diseases. Human periodontal ligament stem cells (hPDLSCs) is a distinctive subgroup of mesenchymal stem cells, which play a crucial role in periodontal supportive tissues, but their application value hasn't been fully explored yet. As a regulatory subunit of PI3K, PIK3R3's role in stem cell regulation remains poorly comprehended.

OBJECTIVES

This study aims to explore the regulatory effect of PIK3R3 on differentiation and senescence of hPDLSCs and the underlying mechanism, as well as whether overexpression of PIK3R3 mitigate alveolar bone loss in aged rats.

METHODS

Human PDLSC lines with both PIK3R3 knockdown and overexpression are established. Osteogenic, adipogenic, chondrogenic and senescent induction are used to test the effect of PIK3R3 on senescence in vitro. Model of alveolar bone loss in aged mice is used to reveal the effect of PIK3R3 in vivo. FOXO1 siRNA is used for mechanism exploration.

RESULTS

Knockdown of PIK3R3 inhibits the mRNA and protein expression of markers in osteogenic, adipogenic, and chondrogenic differentiation of hPDLSCs but promotes in vitro senescence of hPDLSCs, including senescence markers expression, telomerase density and reactive oxygen species. Overexpression of PIK3R3 has the opposite effect. Furthermore, the result of Micro-CT and tissue section shows that overexpression of PIK3R3 in elder rats mitigates alveolar bone loss. Mechanistically, PIK3R3 regulates senescence of hPDLSCs through modulating FOXO1 expression. Expression of FOXO1 is altered when PIK3R3 is knocked down or overexpressed in senescent medium. Knockdown of FOXO1 promotes senescence of hPDLSCs and the senescence promoting effect of knocking down PIK3R3 is weakened when FOXO1 is highly expressed.

CONCLUSION

These findings indicate that PIK3R3 modulates senescence of hPDLSCs by regulating FOXO1 expression and shows promise as a therapeutic target for mitigating age-related alveolar bone loss.

Decoding Cytokine Dynamics: Wharton's Jelly Stromal Cells and Chondro-Differentiates in PHA-Stimulated Co-Culture

INTRODUCTION

Articular cartilage damage presents a significant clinical challenge, with limited options for effective regeneration. Mesenchymal stromal cells (MSCs) derived from Wharton's jelly (WJ) are a promising cell source for cartilage repair due to their regenerative and immunomodulatory properties. While undifferentiated MSCs have demonstrated potent immunoregulatory effects, the immunomodulatory potential of chondrocytes derived from WJ-MSCs remains underexplored, particularly under inflammatory conditions. This study investigates the differential cytokine expression profiles of WJ-MSC-derived chondrocytes and undifferentiated MSCs under inflammatory stimulation with phytohemagglutinin (PHA) to understand their immunomodulatory capacities.

MATERIALS AND METHODS

WJ-MSCs were differentiated into chondrocytes using a micromass culture system. Differentiated chondrocytes were then co-cultured with immune cells under PHA-induced inflammatory conditions. Control groups included co-cultured cells without PHA activation and chondrocytes activated with PHA in the absence of immune cell interaction. Cytokine expression profiles were analyzed using the RT2 Customized Gene Array to evaluate pro- and anti-inflammatory markers. Morphological changes were assessed microscopically. The immunomodulatory responses of chondrocytes were compared to those of undifferentiated MSCs under the same experimental conditions.

RESULTS

Chondrocytes co-cultured with immune cells under PHA activation exhibited downregulation of IDO, HLA-G, PDGF, IL-10, TNF-α, IL-6, and IFN-γ compared to undifferentiated MSCs in similar conditions. In non-PHA co-cultured conditions, chondrocytes showed increased expression of IL-6, IFN-γ, IL-4, VEGF, iNOS, PDGF, PTGS-2 and TGF-β, while TNF-α, IL-10, IDO and HLA-G were decreased. In contrast, chondrocytes activated with PHA without immune cell interaction displayed reduced expression of HLA-G and TNF-α, with no significant changes in IL-6, IFN-γ, IL-4, IL-10, VEGF, PDGF, PTGS-2, TGF-β, IDO, and iNOS compared to PHA-stimulated undifferentiated MSCs.

CONCLUSION

This study demonstrates that chondrocytes derived from WJ-MSCs exhibit limited immunomodulatory potential compared to undifferentiated MSCs, particularly under PHA-induced inflammatory conditions. Undifferentiated MSCs showed superior regulation of key cytokines associated with immune modulation. These findings suggest that maintaining MSCs in an undifferentiated state may be advantageous for therapeutic applications targeting inflammatory conditions, such as osteoarthritis. Future research should explore strategies to enhance the immunomodulatory efficacy of chondrocytes, potentially through genetic modification or adjunctive therapies.

Functional heterogeneity of mesenchymal stem cells and their therapeutic potential in the K18-hACE2 mouse model of SARS-CoV-2 infection

BACKGROUND

Despite many years of investigation into mesenchymal stem cells (MSCs) and their potential for treating inflammatory conditions such as COVID-19, clinical outcomes remain variable due to factors like donor variability, different tissue sources, and diversity within MSC populations. Variations in MSCs' secretory and proliferation profiles, and their proteomic and transcriptional characteristics significantly influence their therapeutic potency, highlighting the need for enhanced characterization methods to better predict their efficacy. This study aimed to evaluate the biological characteristics of MSCs from different tissue origins, selecting the most promising line for further validation in a K18-hACE2 mouse model of SARS-CoV-2 infection.

METHODS

We studied nine MSC lines sourced from either bone marrow (hBMMSC), dental pulp (hDPMSC), or umbilical cord tissue (hUCMSC). The cells were assessed for their proliferative capacity, immunophenotype, trilineage differentiation, proteomic profile, and in vitro immunomodulatory potential by co-culture with activated lymphocytes. The most promising MSC line was selected for further experimental validation using the K18-hACE2 mouse model of SARS-CoV-2 infection.

RESULTS

The analyzed cells met the minimum criteria for defining MSCs, including the expression of surface molecules and differentiation capacity, showing genetic stability and proliferative potential. Proteomic analysis revealed distinct protein profiles that correlate with the tissue origin of MSCs. The immunomodulatory response exhibited variability, lacking a discernible pattern associated with their origin. In co-culture assays with lymphocytes activated with anti-CD3/CD28 beads, all MSC lines demonstrated the ability to inhibit TNF-α, to induce TGF-β and Indoleamine 2,3-dioxygenase (IDO), with varying degrees of inhibition observed for IFN-γ and IL-6, or induction of IL-10 expression. A module of proteins was found to statistically correlate with the potency of IL-6 modulation, leading to the selection of one of the hUCMSCs as the most promising line. Administration of hUCMSC to SARS-CoV-2-infected K18 mice expressing hACE2 was effective in improving lung histology and modulating of a panel of cytokines.

CONCLUSIONS

Our study assessed MSCs derived from various tissues, uncovering significant variability in their characteristics and immunomodulatory capacities. Particularly, hUCMSCs demonstrated potential in mitigating lung pathology in a SARS-CoV-2 infection model, suggesting their promising therapeutic efficacy.

Mesenchymal stem cell-mediated adipogenic transformation: a key driver of oral squamous cell carcinoma progression

BACKGROUND

Interaction between mesenchymal stem cells (MSCs) and oral squamous cell carcinoma (OSCC) cells plays a major role in OSCC progression. However, little is known about adipogenic differentiation alteration in OSCC-derived MSCs (OSCC-MSCs) and how these alterations affect OSCC growth.

METHODS

MSCs were successfully isolated and cultured from normal gingival tissue, OSCC peritumoral tissue, and OSCC tissue. This included gingiva-derived MSCs (GMSCs), OSCC adjacent noncancerous tissues-derived MSCs (OSCCN-MSCs), and OSCC-MSCs. The adipogenic and osteogenic differentiation capabilities of these cells were evaluated using Oil Red O and Alizarin Red S staining, respectively. OSCC cells were then co-cultured with either OSCC-MSCs or GMSCs to assess the impact on OSCC cell proliferation and migration. Subcutaneous xenograft experiments were conducted in BALB/c-nu mice to further investigate the effects in vivo. Additionally, immunohistochemical staining was performed on clinical samples to determine the expression levels of fatty acid synthase (FASN) and the proliferation marker Ki67.

RESULTS

OSCC-MSCs exhibited enhanced adipogenic differentiation and reduced osteogenic differentiation compared to GMSCs. OSCC-MSCs significantly increased the proliferation and migration of OSCC cells relative to GMSCs and promoted tumor growth in mouse xenografts. Lipid droplet accumulation in the stroma was significantly more pronounced in OSCC + OSCC-MSCs xenografts compared to OSCC + GMSCs xenografts. Free fatty acids (FFAs) levels were elevated in OSCC tissues compared to normal gingival tissues. Moreover, OSCC-MSCs consistently secreted higher levels of FFAs in condition medium than GMSCs. Knockdown of FASN in OSCC-MSCs reduced their adipogenic potential and inhibited their ability to promote OSCC cell proliferation and migration. Clinical sample analysis confirmed higher FASN expression in OSCC stroma, correlating with larger tumor size and increased Ki67 expression in cancer tissues, and was associated with poorer overall survival.

CONCLUSIONS

OSCC-MSCs promoted OSCC proliferation and migration by upregulating FASN expression and facilitating FFAs secretion. Our results provide new insight into the mechanism of OSCC progression and suggest that the FASN of OSCC-MSCs may be potential targets of OSCC in the future.

Antimicrobial activity of adipose-derived mesenchymal stromal cell secretome against methicillin-resistant Staphylococcus aureus

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is still a growing concern in the field of antimicrobial resistance due to its resistance to conventional antibiotics and its association with high mortality rates. Mesenchymal stromal cells (MSCs) have been shown as a promising and attractive alternative treatment for bacterial infections, due to their antibacterial properties and potential to bypass traditional resistance mechanisms. This study aims to shed light on the antibacterial potential of adipose-derived mesenchymal stromal cell (AD-MSC) secretome against clinical isolates of Staphylococcus spp., including MRSA strains.

METHODS

Using the Kirby-Bauer disk diffusion method, broth microdilution assays, and colony-forming unit (CFU) counting, the antibacterial activity of AD-MSC secretome was assessed. These tests were first conducted on Staphylococcus (S.) aureus ATCC 25923, then on 73 clinical isolates including MRSA strains. Further molecular analysis was performed to identify resistant genes in MRSA isolates.

RESULTS

The AD-MSC secretome demonstrated significant antibacterial activity against S. aureus ATCC with a 32 mm inhibition zone. 96% of the collected staphylococcal clinical isolates showed susceptibility to the secretome with 87.5% inhibition observed in MRSA isolates, along with 100% in MSSA, MSSE, and MRSE strains. Molecular analysis revealed that MRSA strains resistant to the secretome harbored mecA, ermA, and ermB genes. Additionally, the mecA-negative MRSA strains remained susceptible to the secretome, suggesting alternative resistance mechanisms.

CONCLUSION

These findings emphasize the ability of AD-MSCs secretome as a promising alternative for treating antibiotic-resistant infections, with potential applications in combating MRSA. However, further research is required to explore its clinical applications as a complementary or standalone therapy for resistant infections.

SARS-CoV-2 Impairs Osteoblast Differentiation Through Spike Glycoprotein and Cytokine Dysregulation

Pulmonary and extrapulmonary manifestations have been reported following infection with SARS-CoV-2, the causative agent of COVID-19. The virus persists in multiple organs due to its tropism for various tissues, including the skeletal system. This study investigates the effects of SARS-CoV-2 infection, including both ancestral and Omicron viral strains, on differentiating mesenchymal stem cells (MSCs), the precursor cells, into osteoblasts. Although both viral strains can productively infect osteoblasts, precursor cell infection remained abortive. Viral exposure during osteoblast differentiation demonstrates that both variants inhibit mineral and organic matrix deposition. This is accompanied by reduced expression of runt-related transcription factor 2 (RUNX2) and increased levels of interleukin-6 (IL-6), a cytokine that negatively regulates osteoblast differentiation. Furthermore, the upregulation of receptor activator of nuclear factor kappa B ligand (RANKL) strongly suggests that the ancestral and Omicron variants may disrupt bone homeostasis by promoting osteoclast differentiation, ultimately leading to the formation of bone-resorbing cells. This process is dependent of spike glycoprotein since its neutralization significantly reduced the effect of infective SARS-CoV-2 and UV-C inactivated virus. This study underscores the capacity of ancestral and Omicron SARS-CoV-2 variants to disrupt osteoblast differentiation, a process essential for preserving the homeostasis and functionality of bone tissue.

The dynamic interaction of pediatric ALL cells and MSCs: influencing leukemic cell survival and modulating MSC β-catenin expression

Bone marrow mesenchymal stromal cells (BM-MSCs) are integral components of the bone marrow microenvironment, playing a crucial role in supporting hematopoiesis. Recent studies have investigated the potential involvement of BM-MSCs in the pathophysiology of acute lymphoblastic leukemia (ALL). However, the exact contribution of BM-MSCs to leukemia progression remains unclear because of conflicting findings and limited characterization. In this study, we compared BM-MSCs derived from pediatric ALL patients with those from matched healthy donors (HDs). Our results indicate that while both ALL-MSCs and HD-MSCs meet the criteria established by the International Society for Cellular Therapy, they exhibit significant differences in proliferation and differentiation capacity. ALL-MSCs displayed markedly lower proliferation rates and reduced osteogenic/adipogenic differentiation potential compared to HD-MSCs. Furthermore, co-culture experiments revealed that MSCs enhance the survival of leukemic blasts through both soluble factors and direct cell-cell interactions, underscoring their anti-apoptotic properties. Importantly, our findings demonstrate that interactions with leukemic cells activate the Wnt/β-catenin signaling pathway in MSCs, suggesting a potential target for therapeutic intervention. Overall, this study enhances our understanding of the role of BM-MSCs in leukemia and highlights β-catenin as a promising target for future therapies.

Immunopathological characteristics and therapeutic effects of UC-MSCs in a pigeon breeder's lung mouse model

Hypersensitivity pneumonitis (HP), including pigeon breeder's lung (PBL), often progresses from acute inflammation to fibrosis, impairing lung function and limiting targeted therapeutic strategies. Mechanistic studies on PBL progression are limited by the lack of preclinical animal models and a predominant focus on patient data. This study explores the immunopathological characteristics of all stages of PBL in mice and evaluates the therapeutic potential of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) during the non-fibrotic stage. PBL models are created in A/J mice through tracheal instillation of pigeon dropping extract (PDE) protein powder. Different doses (0.4 × 10 6, 0.8 × 10 6, and 1.6 × 10 6 cells per animal) and frequencies (1-2 times) are administered to the model. The immunopathological characteristics of PBL and the therapeutic effects of UC-MSCs are assessed using micro-CT, pulmonary function, histopathology, cell counts in BALF, HYP levels, inflammatory factor levels, immunohistochemistry, and fibrosis marker expression in lung tissues. The results show that PDE exposure consistently impairs pulmonary function and increases the levels of inflammation and fibrosis markers as the disease progresses. Model mice experience non-fibrotic stages (acute inflammation) from days 0-36, mild fibrosis from days 37-77, and severe fibrosis from day 78 onwards. UC-MSCs, particularly at the highest dose (1.6 × 10 6 cells), effectively treat non-fibrotic PBL by improving pulmonary function (lung ventilation area recovers) and reducing inflammation and fibrosis. This study successfully establishes PBL mouse models reflecting both the acute (inflammatory) and chronic (fibrotic) stages, and UC-MSCs have the potential to delay fibrosis, providing new therapeutic options for PBL and other inflammation-induced lung fibrotic diseases.

Small extracellular vesicles derived from sequential stimulation of canine adipose-derived mesenchymal stem cells enhance anti-inflammatory activity

BACKGROUND

Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) are recognized for their therapeutic potential in immune modulation and tissue repair, especially in veterinary medicine. This study introduces an innovative sequential stimulation (IVES) technique, involving low-oxygen gas mixture preconditioning using in vitro fertilization gas (IVFG) and direct current electrical stimulation (ES20), to enhance the anti-inflammatory properties of sEVs from canine adipose-derived MSCs (cAD-MSCs). Initial steps involved isolation and comprehensive characterization of cAD-MSCs, including morphology, gene expression, and differentiation potentials, alongside validation of the electrical stimulation protocol. IVFG, ES20, and IVES were applied simultaneously with a control condition. Stimulated cAD-MSCs were evaluated for morphological changes, cell viability, and gene expressions. Conditioned media were collected and purified for sEV isolation on Day1, Day2, and Day3. To validate the efficacy of IVES for sEV production, various analyses were conducted, including microscopic examination, surface marker assessment, zeta-potential measurement, protein quantification, nanoparticle tracking analysis, and determination of anti-inflammatory activity.

RESULTS

We found that IVES demonstrated non-cytotoxicity and induced crucial genotypic changes associated with sEV production in cAD-MSCs. Interestingly, IVFG influenced cellular adaptation, while ES20 induced hypoxia activation. By merging these stimulations, IVES enhanced sEV stability and quality profiles. The cAD-MSC-derived sEVs exhibited anti-inflammatory activity in lipopolysaccharide-induced RAW264.7 macrophages, emphasizing their improved effectiveness without cytotoxicity or immunogenicity. These effects were consistent across day 3 collection, indicating the establishment of an effective protocol for sEV production.

CONCLUSIONS

This research established an innovative sequential stimulation method with positive impact on sEV characteristics including stability, quality, and anti-inflammatory activity. This study not only contributes to the enhancement of sEV production but also sheds light on their functional aspects for therapeutic interventions.

The Differentiation and Regeneration Potential of ABCB5+ Mesenchymal Stem Cells: A Review and Clinical Perspectives

Mesenchymal stem cells (MSCs) are a family of multipotent stem cells that show self-renewal under proliferation, multilineage differentiation, immunomodulation, and trophic function. Thus, these cells, such as adipose tissue-derived mesenchymal stem cells (ADSCs), bone marrow-derived MSCs (BM-MSCs), and umbilical cord-derived mesenchymal stem cells (UC-MSCs), carry great promise for novel clinical treatment options. However, the challenges associated with the isolation of MSCs and the instability of their in vitro expansion remain significant barriers to their clinical application. The plasma membrane-spanning P-glycoprotein ATP-binding cassette subfamily B member 5 positive MSCs (ABCB5+ MSCs) derived from human skin specimens offer a distinctive advantage over other MSCs. They can be easily extracted from the dermis and expanded. In culture, ABCB5+ MSCs demonstrate robust innate homeostasis and a classic trilineage differentiation. Additionally, their ability to modulate the recipients' immune system highlights their potential for allogeneic applications in regenerative medicine. In this review, we primarily discuss the differentiation potential of ABCB5+ MSCs and their perspectives in regenerative medicine.

Effects of Magnesium-Doped Hydroxyapatite Nanoparticles on Bioink Formulation for Bone Tissue Engineering

Bioprinting of nanohydroxyapatite (nHA)-based bioinks has attracted considerable interest in bone tissue engineering. However, the role and relevance of the physicochemical properties of nHA incorporated in a bioink, particularly in terms of its printability and the biological behavior of bioprinted cells, remain largely unexplored. In this study, two bioinspired nHAs with different chemical compositions, crystallinity, and morphologies were synthesized and characterized: a more crystalline, needle-like Mg2+-doped nHA (N-HA) and a more amorphous, rounded Mg2+- and CO32--doped nHA (R-HA). To investigate the effects of the different compositions and morphologies of these nanoparticles on the bioprinting of human bone marrow stromal cells (hBMSCs), gelatin and gelatin methacryloyl (GelMA) were selected as the bioink backbone. The addition of 1% (w/w) of these bioceramic nanoparticles significantly improved the printability of GelMA in terms of extrudability, buildability, and filament spreading. The biological potential of the bioinks was evaluated by examining the hBMSC viability, metabolic activity, and osteogenic differentiation over 21 days. Both nHAs showed high cell viability, with N-HA showing a significant increase in metabolic activity under nonosteogenic conditions and R-HA showing a notable increase with osteogenic stimulation. These results suggest that the two nHAs interact differently with their environment, highlighting the importance of both the chemistry and morphology in bioink performance. In addition, osteogenic differentiation further highlighted how the physicochemical properties of nHAs influence osteogenic markers at both the RNA and protein levels. Clearly, tailoring the physicochemical properties of hydroxyapatite nanoparticles is critical to developing more biomimetic bioinks with great potential for advancing bone bioprinting applications.