Changes in phenotype and differentiation potential of human mesenchymal stem cells aging in vitro

Gel microspheres enhance the stemness of ADSCs by regulating cell-ECM interaction

The gel microsphere culture system (GMCS) showed various advantages for mesenchymal stem cell (MSC) expansion and delivery, such as high specific surface area, small and regular shape, extensive adjustability, and biomimetic properties. Although various technologies and materials have been developed to promote the development of gel microspheres, the differences in the biological status of MSCs between the GMCS and the traditional Petri dish culture system (PDCS) are still unknown, hindering gel microspheres from becoming a culture system as widely used as petri dishes. In the previous study, an excellent "all-in-one" GMCS has been established for the expansion of human adipose-derived MSCs (hADSCs), which showed convenient cell culture operation. Here, we performed transcriptome and proteome sequencing on hADSCs cultured on the "all-in-one" GMCS and the PDCS. We found that hADSCs cultured in the GMCS kept in an undifferentiation status with a high stemness index, whose transcriptome profile is closer to the adipose progenitor cells (APCs) in vivo than those cultured in the PDCS. Further, the high stemness status of hADSCs in the GMCS was maintained through regulating cell-ECM interaction. For application, bilayer scaffolds were constructed by osteo- and chondro-differentiation of hADSCs cultured in the GMCS and the PDCS. The effect of osteochondral regeneration of the bilayer scaffolds in the GMCS group was better than that in the PDCS group. This study revealed the high stemness and excellent functionality of MSCs cultured in the GMCS, which promoted the application of gel microspheres in cell culture and tissue regeneration.

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.

Single cell, Label free Characterisation of Human Mesenchymal Stromal cell Stemness and Future Growth Potential by Autofluorescence Multispectral Imaging

AIM

To use autofluorescence multispectral imaging (AFMI) to develop a non-invasive assay for the in-depth characterisation of human bone marrow derived mesenchymal stromal cells (hBM-MSCs).

METHODS

hBM-MSCs were imaged by AFMI on gridded dishes, stained for endpoints of interest (STRO-1 positivity, alkaline phosphatase, beta galactosidase, DNA content) then relocated and results correlated. Intensity, texture and morphological features were used to characterise the colour distribution of regions of interest, and canonical discriminant analysis was used to separate groups. Additionally, hBM-MSC lines were cultured to arrest, with AFMI images taken after each passage to investigate whether an assay could be developed for growth potential.

RESULTS

STRO-1 positivity could be predicted with a receiver operator characteristic area under the curve (AUC) of 0.67. For spontaneous differentiation this was 0.66, for entry to the cell-cycle it was 0.77 and for senescence it was 0.77. Growth potential (population doublings remaining) was estimated with an RMSPE = 2.296. The Mean Absolute Error of the final prediction model indicated that growth potential could be predicted with an error of ± 1.86 doublings remaining.

CONCLUSIONS

This non-invasive methodology enabled the in-depth characterisation of hBM-MSCs from a single assay. This approach is advantageous for clinical applications as well as research and stands out for the characterisation of both present status as well as future behaviour. The use of data from five MSC lines with heterogenous AFMI profiles supports potential generalisability.

Effect of 660-nm LED photobiomodulation on the proliferation and chondrogenesis of meniscus-derived stem cells (MeSCs)

Meniscus-derived stem cells (MeSCs), a unique type of MSC, have outstanding advantages in meniscal cytotherapy and tissue engineering, but the effects and molecular mechanisms of PBM on MeSCs are still unclear. We used 660-nm LED light with different energy densities to irradiate six human MeSC samples and tested their proliferation rate via cell counting, chondrogenic differentiation capacity via the DMMB assay, mitochondrial activity via the MTT assay, and gene expression via qPCR. The proliferation ability, chondrogenic capacity and mitochondrial activity of the 18 J/cm2 group were greater than those of the 4 J/cm2 and control groups. The mRNA expression levels of Akt, PI3K, TGF-β3, Ki67 and Notch-1 in the 18 J/cm2 group were greater than those in the other groups in most samples. After chondrogenic induction, the expression of Col2A1, Sox9 and Aggrecan in the 18 J/cm2 group was significantly greater than that in the 4 J/cm2 and control groups in most of the samples. The variation in the MTT values and Src, PI3K, Akt, mTOR and GSK3β levels decreased with time. The results showed that 660-nm LED red light promoted proliferation and chondrogenic differentiation and affected the gene expression of MeSCs, and the effects on gene expression and mitochondrial activity decreased with time.

Long-term passage impacts human dental pulp stem cell activities and cell response to drug addition in vitro

Background

Dental pulp stem cells (DPSCs) possess mesenchymal stem cell characteristics and have potential for cell-based therapy. Cell expansion is essential to achieve sufficient cell numbers. However, continuous cell replication causes cell aging in vitro, which usually accompanies and potentially affect DPSC characteristics and activities. Continuous passaging could alter susceptibility to external factors such as drug treatment. Therefore, this study sought to investigate potential outcome of in vitro passaging on DPSC morphology and activities in the absence or presence of external factor.

Methods

Human DPSCs were subcultured until reaching early passages (P5), extended passages (P10), and late passages (P15). Cells were evaluated and compared for cell and nuclear morphologies, cell adhesion, proliferative capacity, alkaline phosphatase (ALP) activity, and gene expressions in the absence or presence of external factor. Alendronate (ALN) drug treatment was used as an external factor.

Results

Continuous passaging of DPSCs gradually lost their normal spindle shape and increased in cell and nuclear sizes. DPSCs were vulnerable to ALN. The size and shape were altered, leading to morphological abnormality and inhomogeneity. Long-term culture and ALN interfered with cell adhesion. DPSCs were able to proliferate irrespective of cell passages but the rate of cell proliferation in late passages was slower. ALN at moderate dose inhibited cell growth. ALN caused reduction of ALP activity in early passage. In contrast, extended passage responded differently to ALN by increasing ALP activity. Late passage showed higher collagen but lower osteocalcin gene expressions compared with early passage in the presence of ALN.

Conclusion

An increase in passage number played critical role in cell morphology and activities as well as responses to the addition of an external factor. The effects of cell passage should be considered when used in basic science research and clinical applications.

Emerging Landscape of Mesenchymal Stem Cell Senescence Mechanisms and Implications on Therapeutic Strategies

Mesenchymal stem cells (MSCs) hold significant promise for regenerative medicine and tissue engineering due to their unique multipotent differentiation ability and immunomodulatory properties. MSC therapy is widely discussed and utilized in clinical treatment. However, during both in vitro expansion and in vivo transplantation, MSCs are prone to senescence, an irreversible growth arrest characterized by morphological, gene expression, and functional changes in genomic regulation. The microenvironment surrounding MSCs plays a crucial role in modulating their senescence phenotype, influenced by factors such as hypoxia, inflammation, and aging status. Numerous strategies targeting MSC senescence have been developed, including senolytics and senomorphic agents, antioxidant and exosome therapies, mitochondrial transfer, and niche modulation. Novel approaches addressing replicative senescence have also emerged. This paper comprehensively reviews the current molecular manifestations of MSC senescence, addresses the environmental impact on senescence, and highlights potential therapeutic strategies to mitigate senescence in MSC-based therapies. These insights aim to enhance the efficacy and understanding of MSC therapies.

Glutaminase-1 inhibition alleviates senescence of Wharton's jelly-derived mesenchymal stem cells via senolysis

Replicative senescence of mesenchymal stem cells (MSCs) caused by repeated cell culture undermines their potential as a cell therapy because of the reduction in their proliferation and therapeutic potential. Glutaminase-1 (GLS1) is reported to be involved in the survival of senescent cells, and inhibition of GLS1 alleviates age-related dysfunction via senescent cell removal. In the present study, we attempted to elucidate the association between MSC senescence and GLS1. We conducted in vitro and in vivo experiments to analyze the effect of GLS1 inhibition on senolysis and the therapeutic effects of MSCs. Inhibition of GLS1 in Wharton's jelly-derived MSCs (WJ-MSCs) reduced the expression of aging-related markers, such as p16, p21, and senescence-associated secretory phenotype genes, by senolysis. Replicative senescence-alleviated WJ-MSCs, which recovered after short-term treatment with bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide 3 (BPTES), showed increased proliferation and therapeutic effects compared to those observed with senescent WJ-MSCs. Moreover, compared to senescent WJ-MSCs, replicative senescence-alleviated WJ-MSCs inhibited apoptosis in serum-starved C2C12 cells, enhanced muscle formation, and hindered apoptosis and fibrosis in mdx mice. These results imply that GLS1 inhibition can ameliorate the therapeutic effects of senescent WJ-MSCs in patients with muscle diseases such as Duchenne muscular dystrophy. In conclusion, GLS1 is a key factor in modulating the senescence mechanism of MSCs, and regulation of GLS1 may enhance the therapeutic effects of senescent MSCs, thereby increasing the success rate of clinical trials involving MSCs.

High-mobility group box 1 fragment ameliorates chronic pancreatitis induced by caerulein in mice

BACKGROUND

Chronic pancreatitis (CP) is a progressive disease characterized by pancreatic fibrosis for which effective treatment options are lacking. Mesenchymal stem cells (MSCs) have shown potential for fibrosis treatment but face limitations in clinical application. The high-mobility group box 1 (HMGB1) fragment mobilizes MSCs from bone marrow into the blood and has emerged as a promising therapeutic agent for tissue regeneration in various pathological conditions. The aim of this study was to investigate the potential therapeutic effects of systemic administration of the HMGB1 fragment in a mouse model of CP.

METHODS

A caerulein-induced CP mouse model was used, and the HMGB1 fragment was administered by tail vein injection. Parameters such as body weight, pancreatic tissue damage, fibrosis, inflammatory cytokine expression, and collagen-related gene expression were evaluated using various assays, including immunohistochemistry, real-time PCR, serum analysis, and single-cell transcriptome analysis. And the migration of MSCs to the pancreas was evaluated using the parabiosis model.

RESULTS

Administration of the HMGB1 fragment was associated with significant improvements in pancreatic tissue damage and fibrosis. It suppressed the expression of inflammatory cytokines and activated platelet-derived growth factor receptor-α+ MSCs, leading to their accumulation in the pancreas. The HMGB1 fragment also shifted gene expression patterns associated with pancreatic fibrosis toward those of the normal pancreas. Systemic administration of the HMGB1 fragment demonstrated therapeutic efficacy in attenuating pancreatic tissue damage and fibrosis in a CP mouse model.

CONCLUSION

These findings highlight the potential of the HMGB1 fragment as a therapeutic target for the treatment of CP.

Mesenchymal stem cells and their potential therapeutic benefits and challenges in the treatment and pathogenesis of gastric cancer

Mesenchymal stem/stromal cells (MSCs) are acknowledged for their remarkable ability to undergo differentiation into various cell types. In addition, they exhibit anti-tumor characteristics, prompting endeavors to modify MSCs for employment in cancer therapies. On the contrary, it is imperative to recognize that MSCs have been extensively linked to pathways that facilitate the advancement of tumors. Numerous research studies have sought to modify MSCs for clinical application; however, the outcomes have been ambiguous, potentially due to the heterogeneity of MSC populations. Furthermore, the conflicting roles of MSCs in suppressing and promoting tumor growth present a challenge to the appropriateness of their use in anti-cancer therapies. Currently, there exists a lack of comprehensive comprehension concerning the anti-tumor and pro-tumor characteristics of MSCs for gastric cancer (GC). This article discusses the influence of MSCs on GC, the underlying mechanisms, the origins of MSCs, and their effects. This review article also elucidates how MSCs exhibit dual characteristics of promoting and inhibiting tumor growth. Hence, it is of utmost importance that clinical inquiries aimed at utilizing MSCs as a therapeutic intervention for cancer consider the potentiality of MSCs to accelerate the progression of GC. It is crucial to exercise caution throughout the process of developing MSC-based cellular therapies to enhance their anti-cancer attributes while simultaneously eliminating their tumor-promoting impacts.

Periodontal granulation tissue - To remove or not to remove, that is the question

Formation of granulation tissue is a fundamental phase in periodontal wound healing with subsequent maturation leading to regeneration or repair. However, persistently inflamed granulation tissue presents in osseous defects as a result of periodontitis and is routinely disrupted and discarded with non-surgical and surgical therapy to facilitate wound healing or improve chances of regeneration. Histological assessment suggests that granulation tissue from periodontitis-affected sites is effectively a chronic inflammatory tissue resulting from impaired wound healing due to persistence of bacterial dysbiotic bioflim. Nevertheless, the immunomodulatory potential and stem cell characteristics in granulation tissue have also raised speculation about the tissue's regenerative potential. This has led to the conception and recent implementation of surgical techniques which preserve granulation tissue with the intention of enhancing innate regenerative potential and improve clinical outcomes. As knowledge of fundamental cellular and molecular functions regulating periodontitis-affected granulation tissue is still scarce, this review aimed to provide a summary of current understanding of granulation tissue in the context of periodontal wound healing. This may provide new insights into clinical practice related to the management of granulation tissue and stimulate further investigation.

3D Niche-Inspired Scaffolds as a Stem Cell Delivery System for the Regeneration of the Osteochondral Interface

The regeneration of the osteochondral unit represents a challenge due to the distinct cartilage and bone phases. Current strategies focus on the development of multiphasic scaffolds that recapitulate features of this complex unit and promote the differentiation of implanted bone-marrow derived stem cells (BMSCs). In doing so, challenges remain from the loss of stemness during in vitro expansion of the cells and the low control over stem cell activity at the interface with scaffolds in vitro and in vivo. Here, this work scaffolds inspired by the bone marrow niche that can recapitulate the natural healing process after injury. The construct comprises an internal depot of quiescent BMSCs, mimicking the bone marrow cavity, and an electrospun (ESP) capsule that "activates" the cells to migrate into an outer "differentiation-inducing" 3D printed unit functionalized with TGF-β and BMP-2 peptides. In vitro, niche-inspired scaffolds retained a depot of nonproliferative cells capable of migrating and proliferating through the ESP capsule. Invasion of the 3D printed cavity results in location-specific cell differentiation, mineralization, secretion of alkaline phosphatase (ALP) and glycosaminoglycans (GAGs), and genetic upregulation of collagen II and collagen I. In vivo, niche-inspired scaffolds are biocompatible, promoted tissue formation in rat subcutaneous models, and regeneration of the osteochondral unit in rabbit models.

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

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

Isolation and Characterization of Meniscus Progenitor Cells From Rat, Rabbit, Goat, and Human

OBJECTIVE

Meniscus progenitor cells (MPCs) have been identified as promising candidates for meniscus regeneration, and it is crucial for us to understand meniscus injury repair mechanism at the cellular level. In this study, we investigate the biological properties of MPCs isolated from different species using the differential adhesion to fibronectin (DAF) technique. We aim to characterize MPCs in different species and evaluate the feasibility of these models for future meniscal investigation.

DESIGN

MPCs were isolated from freshly digested meniscus from rat, rabbit, goat, and human cells using DAF. Biological properties, including proliferation, colony-forming, multilineage differentiation, and migration abilities, were compared in MPCs and their corresponding mixed meniscus cell (MCs) population in each species.

RESULTS

MPCs were successfully isolated by the DAF technique in all species. Rat MPCs appeared cobblestone-like, rabbit MPCs were more polygonal, goat MPCs had a spindle-shaped morphology, human MPCs appear more fibroblast-like. Compared with MCs, isolated MPCs showed progenitor cell characteristics, including multilineage differentiation ability and MSC (mesenchymal stem cells) markers (CD166, CD90, CD44, Stro-1) expression. They also highly expressed fibronectin receptors CD49e and CD49c. MPCs also showed greater proliferation capacity and retained colony-forming ability. Except for goat MPCs showed greater migration abilities than MCs, no significant differences were found in the migration ability between MPCs and MCs in other species.

CONCLUSION

Our study shows that DAF is an effective method for isolating MPCs from rat, rabbit, goat, and human. MPCs in these species demonstrated similar characteristics, including greater proliferation ability and better chondrogenic potential.

Skin rejuvenation through topical application of indocyanine green with diffractive optical element mode of 785 nm picosecond laser in Asian females

BACKGROUND

Indocyanine green (ICG) exhibits robust absorption near 800 nm.

AIMS

To examine the clinical effects of combining ICG with a 785 nm picosecond laser for treating photo-aged skin.

PATIENT/METHODS

A 785 nm 600 picosecond laser was used on the facial area of 16 female patients with Fitzpatrick skin type III and IV (mean age: 58.44 ± 5.24 years) after applying 0.0125% ICG cream. A total of 3000 shots were administered in diffractive optical element mode at a pulse energy of 200 mJ and frequency of 10 Hz. Hyperpigmented lesions were treated using the Zoom handpiece set at a spot size of 3-4 mm, pulse energy of 60-120 mJ, and frequency of 3-7 Hz. Patients underwent five sessions of treatment at intervals of 1-2 weeks. Wrinkles, pores and pigmented lesions were assessed at the initial assessment and 4 weeks after the final treatment using the Modified Fitzpatrick Wrinkle Scale and 10-point visual analog scale, respectively. Skin biopsy of the postauricular area was performed on two consenting patients.

RESULTS

Significant improvements in wrinkles (p = 0.02), pores (p = 0.034), and hyperpigmentation (p = 0.036) were observed, along with increased patient subjective improvement. Adverse effects were transient and well-tolerated. Hematoxylin and eosin and Masson's trichrome staining revealed increased and thickened dermal collagen fibers. Immunohistochemical staining revealed increased expression of collagen I and III throughout the papillary and upper reticular dermis, along with diffuse increase of STRO-1 in the dermis.

CONCLUSIONS

The combined application of a 785 nm picosecond laser and ICG yielded promising clinical outcomes for treating photo-aged skin in Asian patients with Fitzpatrick skin type III and IV.

T. gondii excretory proteins promote the osteogenic differentiation of human bone mesenchymal stem cells via the BMP/Smad signaling pathway

BACKGROUND

Bone defects, resulting from substantial bone loss that exceeds the natural self-healing capacity, pose significant challenges to current therapeutic approaches due to various limitations. In the quest for alternative therapeutic strategies, bone tissue engineering has emerged as a promising avenue. Notably, excretory proteins from Toxoplasma gondii (TgEP), recognized for their immunogenicity and broad spectrum of biological activities secreted or excreted during the parasite's lifecycle, have been identified as potential facilitators of osteogenic differentiation in human bone marrow mesenchymal stem cells (hBMSCs). Building on our previous findings that TgEP can enhance osteogenic differentiation, this study investigated the molecular mechanisms underlying this effect and assessed its therapeutic potential in vivo.

METHODS

We determined the optimum concentration of TgEP through cell cytotoxicity and cell proliferation assays. Subsequently, hBMSCs were treated with the appropriate concentration of TgEP. We assessed osteogenic protein markers, including alkaline phosphatase (ALP), Runx2, and Osx, as well as components of the BMP/Smad signaling pathway using quantitative real-time PCR (qRT-PCR), siRNA interference of hBMSCs, Western blot analysis, and other methods. Furthermore, we created a bone defect model in Sprague-Dawley (SD) male rats and filled the defect areas with the GelMa hydrogel, with or without TgEP. Microcomputed tomography (micro-CT) was employed to analyze the bone parameters of defect sites. H&E, Masson and immunohistochemical staining were used to assess the repair conditions of the defect area.

RESULTS

Our results indicate that TgEP promotes the expression of key osteogenic markers, including ALP, Runx2, and Osx, as well as the activation of Smad1, BMP2, and phosphorylated Smad1/5-crucial elements of the BMP/Smad signaling pathway. Furthermore, in vivo experiments using a bone defect model in rats demonstrated that TgEP markedly promoted bone defect repair.

CONCLUSION

Our results provide compelling evidence that TgEP facilitates hBMSC osteogenic differentiation through the BMP/Smad signaling pathway, highlighting its potential as a therapeutic approach for bone tissue engineering for bone defect healing.

Adipose Tissue and Umbilical Cord Tissue: Potential Sources of Mesenchymal Stem Cells for Liver Fibrosis Treatment

Background/Aims

Mesenchymal stem cells (MSCs) are potential alternatives for liver fibrosis treatment; however, their optimal sources remain uncertain. This study compares the ex-vivo expansion characteristics of MSCs obtained from adipose tissue (AT) and umbilical cord (UC) and assesses their therapeutic potential for liver fibrosis treatment.

Methods

Since MSCs from early to mid-passage numbers (P2-P6) are preferable for cellular therapy, we investigated the growth kinetics of AT-MSCs and UC-MSCs up to P6 and evaluated their therapeutic effects in a rat model of liver fibrosis induced by diethylnitrosamine.

Results

Results from the expansion studies demonstrated that both cell types exhibited bona fide characteristics of MSCs, including surface antigens, pluripotent gene expression, and differentiation potential. However, AT-MSCs demonstrated a shorter doubling time (58.2 ± 7.3 vs. 82.3 ± 4.3 h; P < 0.01) and a higher population doubling level (10.1 ± 0.7 vs. 8.2 ± 0.3; P < 0.01) compared to UC-MSCs, resulting in more cellular yield (230 ± 9.0 vs. 175 ± 13.2 million) in less time. Animal studies demonstrated that both MSC types significantly reduced liver fibrosis (P < 0.05 vs. the control group) while also improving liver function and downregulating fibrosis-associated gene expression.

Conclusion

AT-MSCs and UC-MSCs effectively reduce liver fibrosis. However, adipose cultures display an advantage by yielding a higher number of MSCs in a shorter duration, rendering them a viable choice for scenarios requiring immediate single-dose administration, often encountered in clinical settings.

Recent advances in the adjunctive management of diabetic foot ulcer: Focus on noninvasive technologies

Diabetic foot ulcer (DFU) is one of the most costly and serious complications of diabetes. Treatment of DFU is usually challenging and new approaches are required to improve the therapeutic efficiencies. This review aims to update new and upcoming adjunctive therapies with noninvasive characterization for DFU, focusing on bioactive dressings, bioengineered tissues, mesenchymal stem cell (MSC) based therapy, platelet and cytokine-based therapy, topical oxygen therapy, and some repurposed drugs such as hypoglycemic agents, blood pressure medications, phenytoin, vitamins, and magnesium. Although the mentioned therapies may contribute to the improvement of DFU to a certain extent, most of the evidence come from clinical trials with small sample size and inconsistent selections of DFU patients. Further studies with high design quality and adequate sample sizes are necessitated. In addition, no single approach would completely correct the complex pathogenesis of DFU. Reasonable selection and combination of these techniques should be considered.

Enhancing Osteoblast Differentiation from Adipose-Derived Stem Cells Using Hydrogels and Photobiomodulation: Overcoming In Vitro Limitations for Osteoporosis Treatment

Osteoporosis represents a widespread and debilitating chronic bone condition that is increasingly prevalent globally. Its hallmark features include reduced bone density and heightened fragility, which significantly elevate the risk of fractures due to the decreased presence of mature osteoblasts. The limitations of current pharmaceutical therapies, often accompanied by severe side effects, have spurred researchers to seek alternative strategies. Adipose-derived stem cells (ADSCs) hold considerable promise for tissue repair, albeit they encounter obstacles such as replicative senescence in laboratory conditions. In comparison, employing ADSCs within three-dimensional (3D) environments provides an innovative solution, replicating the natural extracellular matrix environment while offering a controlled and cost-effective in vitro platform. Moreover, the utilization of photobiomodulation (PBM) has emerged as a method to enhance ADSC differentiation and proliferation potential by instigating cellular stimulation and facilitating beneficial performance modifications. This literature review critically examines the shortcomings of current osteoporosis treatments and investigates the potential synergies between 3D cell culture and PBM in augmenting ADSC differentiation towards osteogenic lineages. The primary objective of this study is to assess the efficacy of combined 3D environments and PBM in enhancing ADSC performance for osteoporosis management. This research is notably distinguished by its thorough scrutiny of the existing literature, synthesis of recent advancements, identification of future research trajectories, and utilization of databases such as PubMed, Scopus, Web of Science, and Google Scholar for this literature review. Furthermore, the exploration of biomechanical and biophysical stimuli holds promise for refining treatment strategies. The future outlook suggests that integrating PBM with ADSCs housed within 3D environments holds considerable potential for advancing bone regeneration efforts. Importantly, this review aspires to catalyse further advancements in combined therapeutic strategies for osteoporosis regeneration.

The Survival of Human Intervertebral Disc Nucleus Pulposus Cells under Oxidative Stress Relies on the Autophagy Triggered by Delphinidin

Delphinidin (Delp), a natural antioxidant, has shown promise in treating age-related ailments such as osteoarthritis (OA). This study investigates the impact of delphinidin on intervertebral disc degeneration (IVDD) using human nucleus pulposus cells (hNPCs) subjected to hydrogen peroxide. Various molecular and cellular assays were employed to assess senescence, extracellular matrix (ECM) degradation markers, and the activation of AMPK and autophagy pathways. Initially, oxidative stress (OS)-induced hNPCs exhibited notably elevated levels of senescence markers like p53 and p21, which were mitigated by Delp treatment. Additionally, Delp attenuated IVDD characteristics including apoptosis and ECM degradation markers in OS-induced senescence (OSIS) hNPCs by downregulating MMP-13 and ADAMTS-5 while upregulating COL2A1 and aggrecans. Furthermore, Delp reversed the increased ROS production and reduced autophagy activation observed in OSIS hNPCs. Interestingly, the ability of Delp to regulate cellular senescence and ECM balance in OSIS hNPCs was hindered by autophagy inhibition using CQ. Remarkably, Delp upregulated SIRT1 and phosphorylated AMPK expression while downregulating mTOR phosphorylation in the presence of AICAR (AMPK activator), and this effect was reversed by Compound C, AMPK inhibitor. In summary, our findings suggest that Delp can safeguard hNPCs from oxidative stress by promoting autophagy through the SIRT1/AMPK/mTOR pathway.

Fibronectin and vitronectin alleviate adipose-derived stem cells senescence during long-term culture through the AKT/MDM2/P53 pathway

Cellular senescence plays a role in the development of aging-associated degenerative diseases. Cell therapy is recognized as a candidate treatment for degenerative diseases. To achieve the goal of cell therapy, the quality and good characteristics of cells are concerned. Cell expansion relies on two-dimensional culture, which leads to replicative senescence of expanded cells. This study aimed to investigate the effect of cell culture surface modification using fibronectin (FN) and vitronectin (VN) in adipose-derived stem cells (ADSCs) during long-term expansion. Our results showed that ADSCs cultured in FN and VN coatings significantly enhanced adhesion, proliferation, and slow progression of cellular senescence as indicated by lower SA-β-gal activities and decreased expression levels of genes including p16, p21, and p53. The upregulation of integrin α5 and αv genes influences phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K), and AKT proteins. FN and VN coatings upregulated AKT and MDM2 leading to p53 degradation. Additionally, MDM2 inhibition by Nutlin-3a markedly elevated p53 and p21 expression, increased cellular senescence, and induced the expression of inflammatory molecules including HMGB1 and IL-6. The understanding of FN and VN coating surface influencing ADSCs, especially senescence characteristics, offers a promising and practical point for the cultivation of ADSCs for future use in cell-based therapies.

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.

Podoplanin depletion in tonsil-derived mesenchymal stem cells induces cellular senescence via regulation of the p16Ink4a/Rb pathway

BACKGROUND

Mesenchymal stem cells (MSCs) are widely used in the development of therapeutic tools in regenerative medicine. However, their quality decreases during in vitro expansion because of heterogeneity and acquired cellular senescence. We investigated the potential role of podoplanin (PDPN) in minimizing cellular senescence and maintaining the stemness of tonsil-derived MSCs (TMSCs).

METHODS

TMSCs were isolated from human tonsil tissues using an enzymatic method, expanded, and divided into two groups: early-passaged TMSCs, which were cultured for 3-7 passages, and late-passaged TMSCs, which were passaged more than 15 times. The TMSCs were evaluated for cellular senescence and MSC characteristics, and PDPN-positive and -negative cells were identified by fluorescence-activated cell sorting. In addition, MSC features were assessed in siRNA-mediated PDPN-depleted TMSCs.

RESULTS

TMSCs, when passaged more than 15 times and becoming senescent, exhibited reduced proliferative rates, telomere length, pluripotency marker (NANOG, OCT4, and SOX2) expression, and tri-lineage differentiation potential (adipogenesis, chondrogenesis, or osteogenesis) compared to cells passaged less than five times. Furthermore, PDPN protein levels significantly decreased in a passage-dependent manner. PDPN-positive cells maintained their stemness characteristics, such as MSC-specific surface antigen (CD14, CD34, CD45, CD73, CD90, and CD105) and pluripotency marker expression, and exhibited higher tri-lineage differentiation potential than PDPN-negative cells. SiRNA-mediated silencing of PDPN led to decreased cell-cycle progression, proliferation, and migration, indicating the significance of PDPN as a preliminary senescence-related factor. These reductions directly contributed to the induction of cellular senescence via p16Ink4a/Rb pathway activation.

CONCLUSION

PDPN may serve as a novel biomarker to mitigate cellular senescence in the clinical application of MSCs.

Development of Subcutaneous SSEA3- or SSEA4-Positive Cell Capture Device

Securing high-quality cell sources is important in regenerative medicine. In this study, we developed a device that can accumulate autologous stem cells in the body. When small wire-assembled molds were embedded in the dorsal subcutaneous pouches of beagles for several weeks, collagen-based tissues with minimal inflammation formed inside the molds. At 3 weeks of embedding, the outer areas of the tissues were composed of immature type III collagen with large amounts of cells expressing SSEA3 or SSEA4 markers, in addition to growth factors such as HGF or VEGF. When separated from the tissues by collagenase treatment, approximately four million cells with a proportion of 70% CD90-positive and 20% SSEA3- or SSEA4-positive cells were recovered from the single mold. The cells could differentiate into bone or cartilage cells. The obtained cell-containing tissues are expected to have potential as therapeutic materials or cell sources in regenerative medicine.

Osteogenic Differentiation Potential of iMSCs on GelMA-BG-MWCNT Nanocomposite Hydrogels

The ability of bone biomaterials to promote osteogenic differentiation is crucial for the repair and regeneration of osseous tissue. The development of a temporary bone substitute is of major importance in enhancing the growth and differentiation of human-derived stem cells into an osteogenic lineage. In this study, nanocomposite hydrogels composed of gelatin methacryloyl (GelMA), bioactive glass (BG), and multiwall carbon nanotubes (MWCNT) were developed to create a bone biomaterial that mimics the structural and electrically conductive nature of bone that can promote the differentiation of human-derived stem cells. GelMA-BG-MWCNT nanocomposite hydrogels supported mesenchymal stem cells derived from human induced pluripotent stem cells, hereinafter named iMSCs. Cell adhesion was improved upon coating nanocomposite hydrogels with fibronectin and was further enhanced when seeding pre-differentiated iMSCs. Osteogenic differentiation and mature mineralization were promoted in GelMA-BG-MWCNT nanocomposite hydrogels and were most evidently observed in the 70-30-2 hydrogels, which could be due to the stiff topography characteristic from the addition of MWCNT. Overall, the results of this study showed that GelMA-BG-MWCNT nanocomposite hydrogels coated with fibronectin possessed a favorable environment in which pre-differentiated iMSCs could better attach, proliferate, and further mature into an osteogenic lineage, which was crucial for the repair and regeneration of bone.

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

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

Enhancement of the function of mesenchymal stem cells by using a GMP-grade three-dimensional hypoxic large-scale production system

Background

Efficiently increasing the production of clinical-grade mesenchymal stem cells (MSCs) is crucial for clinical applications. Challenges with the current planar culture methods include scalability issues, labour intensity, concerns related to cell senescence, and heterogeneous responses. This study aimed to establish a large-scale production system for MSC generation. In addition, a comparative analysis of the biological differences between MSCs cultured under various conditions was conducted.

Methods and materials

We developed a GMP-grade three-dimensional hypoxic large-scale production (TDHLSP) system for MSCs using self-fabricated glass microcarriers and a multifunctional bioreactor. Different parameters, including cell viability, cell diameter, immunophenotype, morphology, karyotype, and tumourigenicity were assessed in MSCs cultured using different methods. Single-cell RNA sequencing (scRNA-seq) revealed pathways and genes associated with the enhanced functionality of MSCs cultured in three dimensions under hypoxic conditions (3D_Hypo MSCs). Moreover, CD142 knockdown in 3D_Hypo MSCs confirmed its in vitro functions.

Results

Inoculating 2 × 108 MSCs into a 2.6 L bioreactor in the TDHLSP system resulted in a final scale of 4.6 × 109 3D_Hypo MSCs by day 10. The 3D_Hypo MSCs retained characteristics of the 2D MSCs, demonstrating their genomic stability and non-tumourigenicity. Interestingly, the subpopulations of 3D_Hypo MSCs exhibited a more uniform distribution and a closer relationship than those of 2D MSCs. The heterogeneity of MSCs was strongly correlated with 'cell cycle' and 'stroma/mesenchyme', with 3D_Hypo MSCs expressing higher levels of activated stroma genes. Compared to 2D MSCs, 3D_Hypo MSCs demonstrated enhanced capabilities in blood vessel formation, TGF-β1 secretion, and inhibition of BV2 proliferation, with maintenance of Senescence-Associated β-Galactosidase (SA-β-gal) negativity. However, the enhanced functions of 3D_Hypo MSCs decreased upon the downregulation of CD142 expression.

Conclusion

The TDHLSP system led to a high overall production of MSCs and promoted uniform distribution of MSC clusters. This cultivation method also enhanced key cellular properties, such as angiogenesis, immunosuppression, and anti-aging. These functionally improved and uniform MSC subpopulations provide a solid basis for the clinical application of stem cell therapies.

Murine bone-derived mesenchymal stem cells undergo molecular changes after a single passage in culture

The rarity of the mesenchymal stem cell (MSC) population poses a significant challenge for MSC research. Therefore, these cells are often expanded in vitro, prior to use. However, long-term culture has been shown to alter primary MSC properties. Additionally, early passage primary MSCs in culture are often assumed to represent the primary MSC population in situ, however, little research has been done to support this. Here, we compared the transcriptomic profiles of murine MSCs freshly isolated from the bone marrow to those that had been expanded in culture for 10 days. We identified that a single passage in culture extensively altered MSC molecular signatures associated with cell cycling, differentiation and immune response. These findings indicate the critical importance of the MSC source, highlighting the need for optimization of culture conditions to minimize the impact on MSC biology and a transition towards in vivo methodologies for the study of MSC function.

Internalization of transferrin-tagged Myxococcus xanthus encapsulins into mesenchymal stem cells

Currently, various functionalized nanocarrier systems are extensively studied for targeted delivery of drugs, peptides, and nucleic acids. Joining the approaches of genetic and chemical engineering may produce novel carriers for precise targeting different cellular proteins, which is important for both therapy and diagnosis of various pathologies. Here we present the novel nanocontainers based on vectorized genetically encoded Myxococcus xanthus (Mx) encapsulin, confining a fluorescent photoactivatable mCherry (PAmCherry) protein. The shells of such encapsulins were modified using chemical conjugation of human transferrin (Tf) prelabeled with a fluorescein-6 (FAM) maleimide acting as a vector. We demonstrate that the vectorized encapsulin specifically binds to transferrin receptors (TfRs) on the membranes of mesenchymal stromal/stem cells (MSCs) followed by internalization into cells. Two spectrally separated fluorescent signals from Tf-FAM and PAmCherry are clearly distinguishable and co-localized. It is shown that Tf-tagged Mx encapsulins are internalized by MSCs much more efficiently than by fibroblasts. It has been also found that unlabeled Tf effectively competes with the conjugated Mx-Tf-FAM formulations. That indicates the conjugate internalization into cells by Tf-TfR endocytosis pathway. The developed nanoplatform can be used as an alternative to conventional nanocarriers for targeted delivery of, e.g., genetic material to MSCs.

Co-culture of STRO1 + human gingival mesenchymal stem cells and human umbilical vein endothelial cells in 3D spheroids: enhanced in vitro osteogenic and angiogenic capacities

Stem cell spheroid is a promising graft substitute for bone tissue engineering. Spheroids obtained by 3D culture of STRO1+ Gingival Mesenchymal Stem Cells (sGMSCs) (sGMSC spheroids, GS) seldom express angiogenic factors, limiting their angiogenic differentiation in vivo. This study introduced a novel stem cell spheroid with osteogenic and angiogenic potential through 3D co-culture of sGMSCs and Human Umbilical Vein Endothelial Cells (HUVECs) (sGMSC/HUVEC spheroids, GHS). GHS with varying seeding ratios of sGMSCs to HUVECs (GHR) were developed. Cell fusion within the GHS system was observed via immunofluorescence. Calcein-AM/PI staining and chemiluminescence assay indicated cellular viability within the GHS. Furthermore, osteogenic and angiogenic markers, including ALP, OCN, RUNX2, CD31, and VEGFA, were quantified and compared with the control group comprising solely of sGMSCs (GS). Incorporating HUVECs into GHS extended cell viability and stability, initiated the expression of angiogenic factors CD31 and VEGFA, and upregulated the expression of osteogenic factors ALP, OCN, and RUNX2, especially when GHS with a GHR of 1:1. Taken together, GHS, derived from the 3D co-culture of sGMSCs and HUVECs, enhanced osteogenic and angiogenic capacities in vitro, extending the application of cell therapy in bone tissue engineering.

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.

Bone Regeneration with Mesenchymal Stem Cells in Scaffolds: Systematic Review of Human Clinical Trials

The aim of the study is to determine the effectiveness of stem cells in scaffolds in the treatment of bone deficits, in regard of bone regeneration, safety, rehabilitation and quality of life in humans. The systematic review was conducted in accordance with PRISMA 2020. A systematic search was conducted in three search engines and two registries lastly in 29-9-2022.for studies of the last 15 years. The risk of bias was assessed with RoB-2, ROBINS- I and NIH Quality of Before-After (Pre-Post) Studies with no Control group. The certainty of the results was assessed with the GRADE assessment tool. Due to heterogeneity, the results were reported in tables, graphs and narratively. The study protocol was published in PROSPERO with registration number CRD42022359049. Of the 10,091 studies retrieved, 14 were meeting the inclusion criteria, and were qualitatively analyzed. 138 patients were treated with mesenchymal stem cells in scaffolds, showing bone healing in all cases, and even with better results than the standard care. The adverse events were mild in most cases and in accordance with the surgery received. When assessed, there was a rehabilitation of the deficit and a gain in quality of life was detected. Although the heterogeneity between the studies and the small number of patients, the administration of mesenchymal stem cells in scaffolds seems safe and effective in the regeneration of bone defects. These results pave the way for the conduction of more clinical trials, with greater number of participants, with more standardized procedures.

Melatonin attenuates dental pulp stem cells senescence due to vitro expansion via inhibiting MMP3

OBJECTIVE

We aimed to identify the crucial genes involved in dental pulp stem cell (DPSC) senescence and evaluate the impact of melatonin on DPSC senescence.

METHODS

Western blotting, SA-β-Gal staining and ALP staining were used to evaluate the senescence and differentiation potential of DPSCs. The optimal concentration of melatonin was determined using the CCK-8 assay. Differentially expressed genes (DEGs) involved in DPSC senescence were obtained via bioinformatics analysis, followed by RT-qPCR. Gain- and loss-of-function studies were conducted to explore the role of MMP3 in DPSC in vitro expansion and in response to melatonin. GSEA was employed to analyse MMP3-related pathways in cellular senescence.

RESULTS

Treatment with 0.1 μM melatonin attenuated cellular senescence and differentiation potential suppression in DPSCs due to long-term in vitro expansion. MMP3 was a crucial gene in senescence, as confirmed by bioinformatics analysis, RT-qPCR and Western blotting. Furthermore, gain- and loss-of-function studies revealed that MMP3 played a regulatory role in cellular senescence. Rescue assays showed that overexpression of MMP3 reversed the effect of melatonin on senescence. GSEA revealed that the MMP3-dependent anti-senescence effect of melatonin was associated with the IL6-JAK-STAT3, TNF-α-Signalling-VIA-NF-κB, COMPLEMENT, NOTCH Signalling and PI3K-AKT-mTOR pathways.

CONCLUSION

Melatonin attenuated DPSC senescence caused by long-term expansion by inhibiting MMP3.

Osteopontin Rejuvenates Senescent Adipose-Derived Stem Cells and Restores their Bone Tissue Regenerative Function

The regenerative function of stem cells is compromised when the proportion of senescent stem cells increases with ageing advance. Therefore, combating stem cell senescence is of great importance for stem cell-based tissue engineering in the elderly, but remains largely unexplored. Osteopontin (OPN), a glycosylated phosphoprotein, is one of the key extracellular matrix molecules in bone tissue. OPN activates various signalling pathways and modulates cellular activities, including cell senescence. However, the role of OPN in stem cell senescence remains largely unknown. This study aims to investigate if OPN modulates cell senescence and bone regenerative function in human adipose-derived mesenchymal stem cells (ASCs), and to determine the underlying mechanisms. We first developed a senescent ASC model using serial passaging until passage 10 (P10), in which senescent cells were characterised by reduced proliferation and osteogenic differentiation capacity compared to P4 ASCs. The conditioned medium from P10 ASCs exhibited a diminished trophic effect on human osteoblasts (HOBs), compared to that from P4 ASCs. P10 ASCs on OPN-coated surface showed rejuvenated phenotype and enhanced osteogenic differentiation. The conditioned medium from P10 ASCs on OPN-coating improved trophic effects on HOBs. OPN regulated the morphology of senescent ASCs, transforming them from a more rounded and flattened cell shape to an elongated shape with a smaller area. These findings demonstrated the effects of OPN in restoring senescent ASCs functions, possibly through a mechanism that involves the modulation of cell morphology, indicating that OPN might hold a great potential for rejuvenating senescent stem cells and could potentially open a new venue for regenerating bone tissue in age-related diseases.

Research progress of autoimmune diseases based on induced pluripotent stem cells

Autoimmune diseases can damage specific or multiple organs and tissues, influence the quality of life, and even cause disability and death. A 'disease in a dish' can be developed based on patients-derived induced pluripotent stem cells (iPSCs) and iPSCs-derived disease-relevant cell types to provide a platform for pathogenesis research, phenotypical assays, cell therapy, and drug discovery. With rapid progress in molecular biology research methods including genome-sequencing technology, epigenetic analysis, '-omics' analysis and organoid technology, large amount of data represents an opportunity to help in gaining an in-depth understanding of pathological mechanisms and developing novel therapeutic strategies for these diseases. This paper aimed to review the iPSCs-based research on phenotype confirmation, mechanism exploration, drug discovery, and cell therapy for autoimmune diseases, especially multiple sclerosis, inflammatory bowel disease, and type 1 diabetes using iPSCs and iPSCs-derived cells.

SOD2 promotes the immunosuppressive function of mesenchymal stem cells at the expense of adipocyte differentiation

The potent immunomodulatory function of mesenchymal stem/stromal cells (MSCs) elicited by proinflammatory cytokines IFN-γ and TNF-α (IT) is critical to resolve inflammation and promote tissue repair. However, little is known about how the immunomodulatory capability of MSCs is related to their differentiation competency in the inflammatory microenvironment. In this study, we demonstrate that the adipocyte differentiation and immunomodulatory function of human adipose tissue-derived MSCs (MSC(AD)s) are mutually exclusive. Mitochondrial reactive oxygen species (mtROS), which promote adipocyte differentiation, were decreased in MSC(AD)s due to IT-induced upregulation of superoxide dismutase 2 (SOD2). Furthermore, knockdown of SOD2 led to enhanced adipogenic differentiation but reduced immunosuppression capability of MSC(AD)s. Interestingly, the adipogenic differentiation was associated with increased mitochondrial biogenesis and upregulation of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PPARGC1A/PGC-1α) expression. IT inhibited PGC-1α expression and decreased mitochondrial mass but promoted glycolysis in an SOD2-dependent manner. MSC(AD)s lacking SOD2 were compromised in their therapeutic efficacy in DSS-induced colitis in mice. Taken together, these findings indicate that the adipogenic differentiation and immunomodulation of MSC(AD)s may compete for resources in fulfilling the respective biosynthetic needs. Blocking of adipogenic differentiation by mitochondrial antioxidant may represent a novel strategy to enhance the immunosuppressive activity of MSCs in the inflammatory microenvironment.

The therapeutic effect of mesenchymal stem cells in diabetic kidney disease

Diabetes mellitus (DM) often causes chronic kidney damage despite best medical practices. Diabetic kidney disease (DKD) arises from a complex interaction of factors within the kidney and the whole body. Targeting specific disease-causing agents using drugs has not been effective in treating DKD. However, stem cell therapies offer a promising alternative by addressing multiple disease pathways and promoting kidney regeneration. Mesenchymal stem cells (MSCs) offer great promise due to their superior accessibility ratio from adult tissues and remarkable modes of action, such as the production of paracrine anti-inflammatory and cytoprotective substances. This review critically evaluates the development of MSC treatment for DKD as it moves closer to clinical application. Results from animal models suggest that systemic MSC infusion may positively impact DKD progression. However, few registered and completed clinical trials exist, and whether the treatments are effective in humans is still being determined. Significant knowledge gaps and research opportunities exist, including establishing the ideal source, dose, and timing of MSC delivery, better understanding of in vivo mechanisms, and developing quantitative indicators to obtain a more significant therapeutic response. This paper reviews recent literature on using MSCs in preclinical and clinical trials in DKD. Potent biomarkers related to DKD are also highlighted, which may help better understand MSCs' action in this disease progression. KEY MESSAGES: Mesenchymal stem cells have anti-inflammatory and paracrine effects in diabetic kidney disease. Mesenchymal stem cells alleviate in animal models having diabetic kidney disease. Mesenchymal stem cells possess promise for the treatment of diabetic kidney disease.

Characterization of 3D Organotypic Culture of Mouse Adipose-Derived Stem Cells

Although stem cells are a promising avenue for harnessing the potential of adipose tissue, conventional two-dimensional (2D) culture methods have limitations. This study explored the use of three-dimensional (3D) cultures to preserve the regenerative potential of adipose-derived stem cells (ADSCs) and investigated their cellular properties. Flow cytometric analysis revealed significant variations in surface marker expressions between the two culture conditions. While 2D cultures showed robust surface marker expressions, 3D cultures exhibited reduced levels of CD44, CD90.2, and CD105. Adipogenic differentiation in 3D organotypic ADSCs faced challenges, with decreased organoid size and limited activation of adipogenesis-related genes. Key adipocyte markers, such as lipoprotein lipase (LPL) and adipoQ, were undetectable in 3D-cultured ADSCs, unlike positive controls in 2D-cultured mesenchymal stem cells (MSCs). Surprisingly, 3D-cultured ADSCs underwent mesenchymal-epithelial transition (MET), evidenced by increased E-cadherin and EpCAM expression and decreased mesenchymal markers. This study highlights successful ADSC organoid formation, notable MSC phenotype changes in 3D culture, adipogenic differentiation challenges, and a distinctive shift toward an epithelial-like state. These findings offer insights into the potential applications of 3D-cultured ADSCs in regenerative medicine, emphasizing the need for further exploration of underlying molecular mechanisms.

In vitro aging alters the gene expression and secretome composition of canine adipose-derived mesenchymal stem cells

Introduction

Canine adipose-derived mesenchymal stem cells (cAD-MSCs) hold therapeutic promise due to their regenerative potential, particularly within their secretome. However, concerns arise regarding the impact of in vitro cultivation necessitated for storing therapeutic doses, prompting this study to comprehensively explore the impact of in vitro aging on gene expression and secretome composition.

Methods

The study involved collecting abdominal adipose tissue samples from nine healthy female dogs, from which cAD-MSCs were extracted and cultured. Stem cells were validated through trilineage differentiation assays and flow cytometry immunophenotyping. Gene expression profiling using RT-qPCR array, and cAD-MSCs secretome LC-MS/MS analysis, were conducted at passages 3 and 6 to reveal gene expression and protein composition alterations during in vitro culture.

Results and Discussion

The results demonstrate that the gene expression and secretome composition of cAD-MSCs were impacted by in vitro aging. Among many alterations in gene expression between two passages, two significant downregulations were noted in the MSC-associated PTPRC and IL10 genes. While the majority of proteins and their functional characteristics were shared between passages, the influence of cell aging on secretome composition is highlighted by 10% of proteins being distinctively expressed in each passage, along with 21 significant up- and downregulations. The functional attributes of proteins detected in passage 3 demonstrated a greater inclination towards supporting the regenerative capacity of cAD-MSCs. Moreover, proteins in passage 6 exhibited a noteworthy correlation with the blood coagulation pathway, suggesting an elevated likelihood of coagulation events. To the best of our knowledge, this study presents the first original perspective on the changes in secretome composition that occur when cAD-MSCs age in vitro. Furthermore, it contributes to broadening the currently restricted knowledge base concerning the secretome of cAD-MSCs. In conclusion, our findings show that the regenerative potential of cAD-MSCs, as well as their secretome, may be compromised by in vitro aging. Therefore, our study suggests a preference for earlier passages when considering these cells for therapeutic applications.

The Role and Prospects of Mesenchymal Stem Cells in Skin Repair and Regeneration

Mesenchymal stem cells (MSCs) have been recognized as a cell therapy with the potential to promote skin healing. MSCs, with their multipotent differentiation ability, can generate various cells related to wound healing, such as dermal fibroblasts (DFs), endothelial cells, and keratinocytes. In addition, MSCs promote neovascularization, cellular regeneration, and tissue healing through mechanisms including paracrine and autocrine signaling. Due to these characteristics, MSCs have been extensively studied in the context of burn healing and chronic wound repair. Furthermore, during the investigation of MSCs, their unique roles in skin aging and scarless healing have also been discovered. In this review, we summarize the mechanisms by which MSCs promote wound healing and discuss the recent findings from preclinical and clinical studies. We also explore strategies to enhance the therapeutic effects of MSCs. Moreover, we discuss the emerging trend of combining MSCs with tissue engineering techniques, leveraging the advantages of MSCs and tissue engineering materials, such as biodegradable scaffolds and hydrogels, to enhance the skin repair capacity of MSCs. Additionally, we highlight the potential of using paracrine and autocrine characteristics of MSCs to explore cell-free therapies as a future direction in stem cell-based treatments, further demonstrating the clinical and regenerative aesthetic applications of MSCs in skin repair and regeneration.

Mesenchymal stem cell-based therapy for osteoporotic bones: Effects of the interaction between cells from healthy and osteoporotic rats on osteoblast differentiation and bone repair

AIMS

Cell therapy utilizing mesenchymal stem cells (MSCs) from healthy donors (HE-MSCs) is a promising strategy for treating osteoporotic bone defects. This study investigated the effects of interaction between HE-MSCs and MSCs from osteoporotic donors (ORX-MSCs) on osteoblast differentiation of MSCs and of HE-MSCs on bone formation in calvarial defects of osteoporotic rats.

MATERIALS AND METHODS

Osteoporosis was induced by orchiectomy (ORX) and its effects on the bone were evaluated by femur microtomography (μCT) and osteoblast differentiation of bone marrow MSCs. HE- and ORX-MSCs were cocultured, and osteoblast differentiation was evaluated using genotypic and phenotypic parameters. HE-MSCs were injected into the calvarial defects of osteoporotic rats, and bone formation was evaluated by μCT, histology, and gene expression of osteoblast markers.

KEY FINDINGS

ORX-induced osteoporosis was revealed by reduced bone morphometric parameters and osteoblast differentiation in ORX-MSCs. HE-MSCs partially recovered the osteogenic potential of ORX-MSCs, whereas HE-MSCs were mildly affected by ORX-MSCs. Additionally, the bone morphogenetic protein and wingless-related integration site signaling pathway components were similarly modulated in cocultures involving ORX-MSCs. HE-MSCs induced meaningful bone formation, highlighting the effectiveness of cell therapy even in osteoporotic bones.

SIGNIFICANCE

These results provide new perspectives on the development of cell-based therapies to regenerate bone defects in patients with disorders that affect bone tissue.

The therapeutic effect of mesenchymal stem cells in diabetic kidney disease

Abstract

Diabetes mellitus (DM) often causes chronic kidney damage despite best medical practices. Diabetic kidney disease (DKD) arises from a complex interaction of factors within the kidney and the whole body. Targeting specific disease-causing agents using drugs has not been effective in treating DKD. However, stem cell therapies offer a promising alternative by addressing multiple disease pathways and promoting kidney regeneration. Mesenchymal stem cells (MSCs) offer great promise due to their superior accessibility ratio from adult tissues and remarkable modes of action, such as the production of paracrine anti-inflammatory and cytoprotective substances. This review critically evaluates the development of MSC treatment for DKD as it moves closer to clinical application. Results from animal models suggest that systemic MSC infusion may positively impact DKD progression. However, few registered and completed clinical trials exist, and whether the treatments are effective in humans is still being determined. Significant knowledge gaps and research opportunities exist, including establishing the ideal source, dose, and timing of MSC delivery, better understanding of in vivo mechanisms, and developing quantitative indicators to obtain a more significant therapeutic response. This paper reviews recent literature on using MSCs in preclinical and clinical trials in DKD. Potent biomarkers related to DKD are also highlighted, which may help better understand MSCs’ action in this disease progression.

Key messages

Mesenchymal Stromal Cells Derived from Dental Tissues: Immunomodulatory Properties and Clinical Potential

Mesenchymal stem/stromal cells (MSCs) are multipotent cells located in different areas of the human body. The oral cavity is considered a potential source of MSCs because they have been identified in several dental tissues (D-MSCs). Clinical trials in which cells from these sources were used have shown that they are effective and safe as treatments for tissue regeneration. Importantly, immunoregulatory capacity has been observed in all of these populations; however, this function may vary among the different types of MSCs. Since this property is of clinical interest for cell therapy protocols, it is relevant to analyze the differences in immunoregulatory capacity, as well as the mechanisms used by each type of MSC. Interestingly, D-MSCs are the most suitable source for regenerating mineralized tissues in the oral region. Furthermore, the clinical potential of D-MSCs is supported due to their adequate capacity for proliferation, migration, and differentiation. There is also evidence for their potential application in protocols against autoimmune diseases and other inflammatory conditions due to their immunosuppressive capacity. Therefore, in this review, the immunoregulatory mechanisms identified at the preclinical level in combination with the different types of MSCs found in dental tissues are described, in addition to a description of the clinical trials in which MSCs from these sources have been applied.

Cellular Senescence in Craniofacial Tissue Regeneration: Inducers, Biomarkers, and Interventions

Craniofacial defects and dental tissue loss have significant negative impacts on the structure and function of jaws and face, often resulting in psychological issues in patients, emphasizing the urgent need for effective craniofacial tissue reconstruction. Unfortunately, natural regeneration of these tissues is limited. Dental-derived mesenchymal stem cells (MSCs) have emerged as a promising resource for tissue engineering-based therapeutic approaches. However, the clinical outcomes of MSC-based transplantation have not met expectations due to various complex reasons, and cellular senescence is recognized as one of the potential mechanisms contributing to the suboptimal results. The quality of MSC decreases during large-scale in vitro expansion, and it is also influenced by the age and the health status of donors. To address these challenges, extensive efforts have been made to developing strategies to combat senescence in tissue engineering, leveraging on current knowledge of underlying mechanisms. This review aims to elucidate the impact of cell senescence in craniofacial and dental regeneration and provides an overview of state-of-the-art antisenescence strategies. We first discuss the potential factors that trigger cell senescence in craniofacial tissue engineering. Then we describe senescence biomarkers, monitoring methods for senescent MSCs, and their underlying molecular mechanisms. The primary focus of this review is on current strategies to inhibit and alleviate cell senescence in tissue engineering. We summarize the strategies concerning the prevention of cell senescence, senolysis, modulation of the senescent associated secretory phenotype, and reversal of senescent MSCs, offering promising opportunities to overcome the challenges associated with cell senescence in craniofacial tissue engineering.

Mesenchymal stem cell-derived exosomes as a promising cell-free therapy for knee osteoarthritis

Osteoarthritis (OA), as a degenerative disease, leads to high socioeconomic burdens and disability rates. The knee joint is typically the most affected and is characterized by progressive destruction of articular cartilage, subchondral bone remodeling, osteophyte formation and synovial inflammation. The current management of OA mainly focuses on symptomatic relief and does not help to slow down the advancement of disease. Recently, mesenchymal stem cells (MSCs) and their exosomes have garnered significant attention in regenerative therapy and tissue engineering areas. Preclinical studies have demonstrated that MSC-derived exosomes (MSC-Exos), as bioactive factor carriers, have promising results in cell-free therapy of OA. This study reviewed the application of various MSC-Exos for the OA treatment, along with exploring the potential underlying mechanisms. Moreover, current strategies and future perspectives for the utilization of engineered MSC-Exos, alongside their associated challenges, were also discussed.

Development of Good Manufacturing Practice-Compatible Isolation and Culture Methods for Human Olfactory Mucosa-Derived Mesenchymal Stromal Cells

Demyelination in the central nervous system (CNS) resulting from injury or disease can cause loss of nerve function and paralysis. Cell therapies intended to promote remyelination of axons are a promising avenue of treatment, with mesenchymal stromal cells (MSCs) a prominent candidate. We have previously demonstrated that MSCs derived from human olfactory mucosa (hOM-MSCs) promote myelination to a greater extent than bone marrow-derived MSCs (hBM-MSCs). However, hOM-MSCs were developed using methods and materials that were not good manufacturing practice (GMP)-compliant. Before considering these cells for clinical use, it is necessary to develop a method for their isolation and expansion that is readily adaptable to a GMP-compliant environment. We demonstrate here that hOM-MSCs can be derived without enzymatic tissue digestion or cell sorting and without culture antibiotics. They grow readily in GMP-compliant media and express typical MSC surface markers. They robustly produce CXCL12 (a key secretory factor in promoting myelination) and are pro-myelinating in in vitro rodent CNS cultures. GMP-compliant hOM-MSCs are comparable in this respect to those grown in non-GMP conditions. However, when assessed in an in vivo model of demyelinating disease (experimental autoimmune encephalitis, EAE), they do not significantly improve disease scores compared with controls, indicating further pre-clinical evaluation is necessary before their advancement to clinical trials.

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.

Preparation of Novel Sea Cucumber Intestinal Peptides to Promote Tibial Fracture Healing in Mice by Inducing Differentiation of Hypertrophic Chondrocytes to the Osteoblast Lineage

SCOPE

Hypertrophic chondrocytes have a decisive regulatory role in the process of fracture healing, and the fate of hypertrophic chondrocytes is not only apoptosis. However, the mechanism of sea cucumber (Stichopus japonicus) intestinal peptide (SCIP) on fracture promotion is still unclear. This study aims to investigate the effect of sea cucumber intestinal peptide on the differentiation fate of hypertrophic chondrocytes in a mouse tibial fracture model.

METHODS AND RESULTS

Mice are subjected to open fractures of the right tibia to establish a tibial fracture model. The results exhibit that the SCIP intervention significantly promotes the mineralization of cartilage callus, decreases the expression of the hypertrophic chondrocyte marker Col X, and increases the expression of the osteoblast marker Col I. Mechanically, SCIP promotes tibial fracture healing by promoting histone acetylation and inhibiting histone methylation, thereby upregulating pluripotent transcription factors induced the differentiation of hypertrophic chondrocytes to the osteoblast lineage in a manner distinct from classical endochondral ossification.

CONCLUSION

This study is the first to report that SCIP can promote tibial fracture healing in mice by inducing the differentiation of hypertrophic chondrocytes to the osteoblast lineage. SCIP may be considered raw material for developing nutraceuticals to promote fracture healing.

Lysine demethylase 3A promotes chondrogenic differentiation of aged human dental pulp stem cells

Background/purpose

Aging severely impairs the beneficial effects of human dental pulp stem cells (hDPSCs) on cartilage regeneration. Lysine demethylase 3A (KDM3A) is involved in regulating mesenchymal stem cells (MSCs) senescence and bone aging. In this study, we investigated the role of KDM3A in hDPSCs aging and whether KDM3A could rejuvenate aged hDPSCs to enhance their chondrogenic differentiation capacity.

Materials and methods

The cellular aging of hDPSCs was evaluated by senescence-associated β-galactosidase (SA-β-gal) staining. Protein levels were determined using Western blot analysis. KDM3A was overexpressed in aged hDPSCs by lentivirus infection. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) were used to determine the mRNA levels of stemness markers. Toluidine blue staining was used to evaluate the effect of KDM3A overexpression on the chondrogenic differentiation of aged hDPSCs.

Results

hDPSCs at passage 12 or treated with etoposide exhibited augmented cellular senescence as evidenced by increased SA-β-gal activity. KDM3A was significantly increased during senescence of hDPSCs. Overexpression of KDM3A did not affect the stemness properties but significantly promoted the chondrogenic differentiation of aged hDPSCs.

Conclusion

Our findings indicate that KDM3A plays an important role in the maintenance of the chondrogenic differentiation capacity of aged hDPSCs and suggest that therapies targeting KDM3A may be a novel strategy to rejuvenate aged hDPSCs.

Age-Related Alterations in Mesenchymal Stem Cell Function: Understanding Mechanisms and Seeking Opportunities to Bypass the Cellular Aging

Undoubtedly, mesenchymal stem cells (MSCs) are the most common cell therapy candidates in clinical research and therapy. They not only exert considerable therapeutic effects to alleviate inflammation and promote regeneration, but also show low-immunogenicity properties, which ensure their safety following allogeneic transplantation. Thanks to the necessity of providing a sufficient number of MSCs to achieve clinically efficient outcomes, prolonged in vitro cultivation is indisputable. However, either following long-term in vitro expansion or aging in elderly individuals, MSCs face cellular senescence. Senescent MSCs undergo an impairment in their function and therapeutic capacities and secrete degenerative factors which negatively affect young MSCs. To this end, designing novel investigations to further elucidate cellular senescence and to pave the way toward finding new strategies to reverse senescence is highly demanded. In this review, we will concisely discuss current progress on the detailed mechanisms of MSC senescence and various inflicted changes following aging in MSC. We will also shed light on the examined strategies underlying monitoring and reversing senescence in MSCs to bypass the comprised therapeutic efficacy of the senescent MSCs.

Corneal Epithelial Development and the Role of Induced Pluripotent Stem Cells for Regeneration

Severe corneal disorders due to infective aetiologies, trauma, chemical injuries, and chronic cicatricial inflammations, are among vision-threatening pathologies leading to permanent corneal scarring. The whole cornea or lamellar corneal transplantation is often used as a last resort to restore vision. However, limited autologous tissue sources and potential adverse post-allotransplantation sequalae urge the need for more robust and strategic alternatives. Contemporary management using cultivated corneal epithelial transplantation has paved the way for utilizing stem cells as a regenerative potential. Humaninduced pluripotent stem cells (hiPSCs) can generate ectodermal progenitors and potentially be used for ocular surface regeneration. This review summarizes the process of corneal morphogenesis and the signaling pathways underlying the development of corneal epithelium, which is key to translating the maturation and differentiation process of hiPSCs in vitro. The current state of knowledge and methodology for driving efficient corneal epithelial cell differentiation from pluripotent stem cells are highlighted.