Adipose-derived and bone marrow mesenchymal stem cells: a donor-matched comparison

Donor tissue type alters the effects of mesenchymal stem cells on human osteoarthritic chondrocytes and their metabolomic profiles

Early post-traumatic osteoarthritis due to sports injuries is not rare and cell-based therapies are currently used in the treatment. Infrapatellar fat pad (IPFP), synovium (Sy) and subcutaneous adipose (S) tissues were obtained for analysis and MSC isolation. Osteoarthritic (OACs) and normal chondrocytes were co-cultured with MSCs for days seven and 14. Tumour necrosis factor alpha (TNFα), cartilage oligomeric matrix protein (COMP) and matrix metalloproteinase-3 (MMP-3) levels were analysed in the supernatants. Untargeted metabolomic analyses were performed in the collected tissues and co-culture media of the experiment groups. TNFα concentrations were lower in IPFP-MSC and Sy-MSC had lower than OACs on day 14. Likewise, MMP-3 decreased in the same groups on day seven and day 14 (p = 0.036). Metabolomic analysis showed distinct profiles in the tissues and metabolic changes in the co-culture media. The extracellular environment of MSCs derived from the IPFP, Sy and S have distinct features and effects on OACs.

Mesenchymal stem cells and their extracellular vesicle therapy for neurological disorders: traumatic brain injury and beyond

Traumatic brain injury (TBI) is a complex condition involving mechanisms that lead to brain dysfunction and nerve damage, resulting in significant morbidity and mortality globally. Affecting ~50 million people annually, TBI's impact includes a high death rate, exceeding that of heart disease and cancer. Complications arising from TBI encompass concussion, cerebral hemorrhage, tumors, encephalitis, delayed apoptosis, and necrosis. Current treatment methods, such as pharmacotherapy with dihydropyridines, high-pressure oxygen therapy, behavioral therapy, and non-invasive brain stimulation, have shown limited efficacy. A comprehensive understanding of vascular components is essential for developing new treatments to improve blood vessel-related brain damage. Recently, mesenchymal stem cells (MSCs) have shown promising results in repairing and mitigating brain damage. Studies indicate that MSCs can promote neurogenesis and angiogenesis through various mechanisms, including releasing bioactive molecules and extracellular vesicles (EVs), which help reduce neuroinflammation. In research, the distinctive characteristics of MSCs have positioned them as highly desirable cell sources. Extensive investigations have been conducted on the regulatory properties of MSCs and their manipulation, tagging, and transportation techniques for brain-related applications. This review explores the progress and prospects of MSC therapy in TBI, focusing on mechanisms of action, therapeutic benefits, and the challenges and potential limitations of using MSCs in treating neurological disorders.

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.

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.

Tissue Engineering 3D-Printed Scaffold Using Allograft/Alginate/Gelatin Hydrogels Coated With Platelet-Rich Fibrin or Adipose Stromal Vascular Fraction Induces Osteogenesis In Vitro

Incorporating autologous patient-derived products has become imperative to enhance the continually improving outcomes in bone tissue engineering. With this objective in mind, this study aimed to evaluate the osteogenic potential of 3D-printed allograft-alginate-gelatin scaffolds coated with stromal vascular fraction (SVF) and platelet-rich fibrin (PRF). The primary goal was to develop a tissue-engineered construct capable of facilitating efficient bone regeneration through the utilization of biomaterials with advantageous properties and patient-derived products. To achieve this goal, 3D-printed gelatin, allograft, and alginate scaffolds were utilized, along with stem cells derived from the buccal fat pad and human-derived components (PRF, SVF). Cells were seeded onto scaffolds, both with and without SVF/PRF, and subjected to comprehensive assessments including adhesion, proliferation, differentiation (gene expression and protein secretion levels), penetration, and gene expression analysis over 14 days. The data was reported as mean ± standard deviation (SD). Two-way or one-way analysis of variance (ANOVA) was performed, followed by a Tukey post hoc test for multiple comparisons. Statistical significance was determined as a p value below 0.05. The scaffolds demonstrated structural integrity, and the addition of PRF coatings significantly enhanced cellular adhesion, proliferation, and differentiation compared to other groups. Gene expression analysis showed increased expression of osteogenic and angiogenic markers in the PRF-coated scaffolds. These findings highlight the promising role of PRF-coated scaffolds in promoting osteogenesis and facilitating bone tissue regeneration. This study emphasizes the development of patient-specific tissue-engineered constructs as a valuable approach for effective bone regeneration.

Alterations in the transcriptome and microRNAs of adipose-derived mesenchymal stem cells from different sites in rats during aging

Aging is an intricate and gradual process characterized by tissue and cellular dysfunction. Adipose-derived mesenchymal stem cells (ADMSCs) experience a functional decline as part of systemic aging. However, the alterations in ADMSCs across various anatomical sites throughout an individual's lifespan remain unclear. To shed light on these changes, we collected white adipose tissue and brown adipose tissue samples from the epididymis, perirenal, inguinal, and scapular regions of young, adult, and aged rats and subsequently isolated ADMSCs for RNA sequencing. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Marker genes of ADMSCs from different sites were identified. Aging triggered notable activation of inflammatory and immune responses while diminishing the ADMSC differentiation capacity and ability to maintain a normal tissue morphology. Furthermore, miR-195-5p and miR-497-3p, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation, were positively correlated with aging. These findings increase our understanding of ADMSC senescence and underscore the unique physiological changes and functions of ADMSCs across different anatomical sites during aging.NEW & NOTEWORTHY Dynamic changes in mRNAs and miRNAs of ADMSCs during aging are shown. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Aging leads to the activation of inflammatory and cellular dysfunction. miR-195-5p and miR-497-3p are positively correlated with aging, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation. ADMSCs associated with different anatomical sites have site-specific markers.

Impact of Porosity and Stiffness of 3D Printed Polycaprolactone Scaffolds on Osteogenic Differentiation of Human Mesenchymal Stromal Cells and Activation of Dendritic Cells

Despite the potential of extrusion-based printing of thermoplastic polymers in bone tissue engineering, the inherent nonporous stiff nature of the printed filaments may elicit immune responses that influence bone regeneration. In this study, bone scaffolds made of polycaprolactone (PCL) filaments with different internal microporosity and stiffness was 3D-printed. It was achieved by combining three fabrication techniques, salt leaching and 3D printing at either low or high temperatures (LT/HT) with or without nonsolvent induced phase separation (NIPS). Printing PCL at HT resulted in stiff scaffolds (modulus of elasticity (E): 403 ± 19 MPa and strain: 6.6 ± 0.1%), while NIPS-based printing at LT produced less stiff and highly flexible scaffolds (E: 53 ± 10 MPa and strain: 435 ± 105%). Moreover, the introduction of porosity by salt leaching in the printed filaments significantly changed the mechanical properties and degradation rate of the scaffolds. Furthermore, this study aimed to show how these variations influence proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (hBMSC) and the maturation and activation of human monocyte-derived dendritic cells (Mo-DC). The cytocompatibility of the printed scaffolds was confirmed by live-dead imaging, metabolic activity measurement, and the continuous proliferation of hBMSC over 14 days. While all scaffolds facilitated the expression of osteogenic markers (RUNX2 and Collagen I) from hBMSC as detected through immunofluorescence staining, the variation in porosity and stiffness notably influenced the early and late mineralization. Furthermore, the flexible LT scaffolds, with porosity induced by NIPS and salt leaching, stimulated Mo-DC to adopt a pro-inflammatory phenotype marked by a significant increase in the expression of IL1B and TNF genes, alongside decreased expression of anti-inflammatory markers, IL10 and TGF1B. Altogether, the results of the current study demonstrate the importance of tailoring porosity and stiffness of PCL scaffolds to direct their biological performance toward a more immune-mediated bone healing process.

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

Background

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

Aim

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

Methods

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

Results

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

Conclusion

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

An In Vivo Assessment of Different Mesenchymal Stromal Cell Tissue Types and Their Differentiation State on a Shape Memory Polymer Scaffold for Bone Regeneration

A combined biomaterial and cell-based solution to heal critical size bone defects in the craniomaxillofacial area is a promising alternative therapeutic option to improve upon autografting, the current gold standard. A shape memory polymer (SMP) scaffold, composed of biodegradable poly(ε-caprolactone) and coated with bioactive polydopamine, was evaluated with mesenchymal stromal cells (MSCs) derived from adipose (ADSC), bone marrow (BMSC), or umbilical cord (UCSC) tissue in their undifferentiated state or pre-differentiated toward osteoblasts for bone healing in a rat calvarial defect model. Pre-differentiating ADSCs and UCSCs resulted in higher new bone volume fraction (15.69% ± 1.64%) compared to empty (i.e., untreated) defects and scaffold-only (i.e., unseeded) groups (4.41% ± 1.11%). Notably, only differentiated UCSCs exhibited a significant increase in new bone volume, surpassing both undifferentiated UCSCs and unseeded scaffolds. Further, differentiated ADSCs and UCSCs had significantly higher trabecular numbers than their undifferentiated counterparts, unseeded scaffolds, and untreated defects. Although the mineral density regenerated within the unseeded scaffold surpassed that achieved with cell seeding, the connectivity of this bone was diminished, as the regenerated tissue confined itself to the spherical morphology of the scaffold pores. The SMP scaffold alone, with undifferentiated BMSCs, with undifferentiated and differentiated ADSCs, and differentiated UCSCs (29.72 ± 1.49 N) demonstrated significant osseointegration compared to empty defects (14.34 ± 2.21 N) after 12 weeks of healing when assessed by mechanical push-out testing. Based on these results and tissue availability to obtain the cells, pre-differentiated ADSCs and UCSCs emerge as particularly promising candidates when paired with the SMP scaffold for repairing critical size bone defects in the craniofacial skeleton.

An Acellular, Self-Healed Trilayer Cryogel for Osteochondral Regeneration in Rabbits

Osteochondral regeneration remains formidable challenges despite significant advances in microsurgery. Herein, an acellular trilayer cryogel (TC) with injectability, tunable pore sizes (80-200 µm), and appropriate compressive modulus (10.8 kPa) is manufactured from self-healable hydrogel under different gelling times through Schiff reaction between chitosan and difunctionalized polyurethane (DFPU). Bioactive molecules (Y27632 and dexamethasone) are respectively loaded in the top and bottom layers to form the Y27632/dexamethasone-loaded trilayer cryogel (Y/DEX-TC). Mesenchymal stem cells (MSCs) seeded in Y/DEX-TC proliferated ≈350% in vitro and underwent chondrogenesis or osteogenesis in response to the respective release of Y or DEX in 14 days. Acupuncture is administered to animals in an attempt to modulate the innate regulatory system and mobilize endogenous MSCs for osteochondral defect regeneration. In vivo rabbit experiments using Y/DEX-TC combined with acupuncture successfully regulate SDF-1 and TGF-β1 levels, which possibly cause MSC migration toward Y/DEX-TC. The synergistic effect of cryogel and acupuncture on immunomodulation is verified with a ≈7.3-fold enhancement of the M2-/M1-macrophage population ratio by treatment of Y/DEX-TC combining acupuncture, significantly greater than ≈1.5-fold increase by acupuncture or ≈2.2-fold increase by Y/DEX-TC alone. This novel strategy using acellular drug-loaded cryogel and accessible acupuncture shows promise in treating osteochondral defects of joint damage.

FKBP5 Regulates the Osteogenesis of Human Adipose-derived Mesenchymal Stem Cells

OBJECTIVE

Human adipose-derived stem cells (ASCs) have shown considerable potential for tissue regeneration. FK506 binding protein (FKBP) 5 is a cochaperone of several proteins. The purpose of this work was to explore the function of FKBP5 in ASC osteogenesis.

METHODS

Lentivirus infection was used to overexpress or knock down FKBP5 in ASCs. To inhibit FKBP5, SAFit2, a specific inhibitor of FKBP5, was used. Next, the osteogenic capacity of ASCs was evaluated via alkaline phosphatase (ALP) staining, and extracellular calcium precipitation was detected via Alizarin red S staining. The binding proteins of FKBP5 were assessed via proteomics and validated via coimmunoprecipitation experiments.

RESULTS

Following osteogenic induction, FKBP5 expression increased at both the mRNA and protein levels. Interestingly, FKBP5 upregulation by lentivirus infection increased the ability of ASCs to differentiate into osteoblasts, as revealed by ALP staining, while ALP activity also increased. Moreover, increased extracellular calcium precipitation confirmed that FKBP5 overexpression promoted ASC osteogenesis into osteocytes. On the other hand, FKBP5 knockdown or functional suppression with SAFit2 decreased this process. Furthermore, the proteomics and coimmunoprecipitation data demonstrated that FKBP5 bound to a variety of proteins in ASCs. These proteins serve as the molecular chaperone base upon which the osteogenesis-regulating activity of FKBP5 rests.

CONCLUSION

Our study revealed that FKBP5 enhances the osteogenesis of ASCs, providing a feasible method for clinical bone tissue engineering applications.

Novel osteogenic peptide from bovine bone collagen hydrolysate: Targeted screening, molecular mechanism, and stability analysis

This study aimed to screen for a novel osteogenic peptide based on the calcium-sensing receptor (CaSR) and explore its molecular mechanism and gastrointestinal stability. In this study, a novel osteogenic peptide (Phe-Ser-Gly-Leu, FSGL) derived from bovine bone collagen hydrolysate was successfully screened by molecular docking and synthesised by solid phase peptide synthesis for further analysis. Cell experiments showed that FSGL significantly enhanced the osteogenic activity of MC3T3-E1 cells by acting on CaSR, including proliferation (152.53%), differentiation, and mineralization. Molecular docking and molecular dynamics further demonstrated that FSGL was a potential allosteric activator of CaSR, that turned on the activation switch of CaSR by closing the Venus flytrap (VFT) domain and driving the two protein chains in the VFT domain to easily form dimers. In addition, 96.03% of the novel osteogenic peptide FSGL was stable during gastrointestinal digestion. Therefore, FSGL showed substantial potential for enhancing the osteogenic activity of osteoblasts. This study provided new insights for the application of CaSR in the targeted screening of osteogenic peptides to improve bone health.

Influence of mesenchymal stem cells from different origins on the therapeutic effectiveness of systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune inflammatory disorder characterized by alterations in the balance between inflammatory and regulatory cytokines. Mesenchymal stem cells (MSCs), which are non-hematopoietic stem cells with multipotent differentiation potential, due to their immunomodulatory, tissue repair, low immunogenicity, and chemotactic properties, have garnered increasing interest in SLE treatment. Studies increasingly reveal the heterogeneous nature of MSC populations. With sources including dental pulp, adipose tissue, bone marrow, and umbilical cord, the therapeutic effects of MSCs on SLE vary depending on their origin. This review consolidates clinical research on MSCs from different sources in treating SLE and analyzes the possible causes underlying these variable outcomes. Additionally, it elucidates five potential factors impacting the outcomes of MSC therapy in SLE: the influence of the microenvironment on MSCs, the complexity and paradoxical aspects of MSC mechanisms in SLE treatment, the heterogeneity of MSCs, the in vivo differentiation potential and post-transplant survival rates of MSCs, and disparities in MSC preparation conditions.

Angelica sinensis polysaccharide facilitates chondrogenic differentiation of adipose-derived stem cells via MDK-PI3K/AKT signaling cascade

OBJECT

Adipose-derived mesenchymal stem cells (ADSCs) have received significant attention in the field of cartilage tissue repair. Angelica sinensis polysaccharide (ASP) can enhance both the proliferation and differentiation of mesenchymal stem cells. Therefore, we intend to explore the effect of ASP on chondrogenic differentiation of ADSCs in vitro, and elucidate the underlying mechanisms.

METHOD

ADSCs were treated with different concentrations of ASP to determine the optimal concentration. The chondrogenic differentiation of ADSCs was evaluated using Alcian blue staining, qRT-PCR, western blot, and IF staining. Transcriptome sequencing was performed to identify the expression profiles of ADSCs before and after ASP treatment, followed by bioinformatic analyses including differential expression analysis, enrichment analysis, and construction of PPI networks to identify differentially expressed genes (DEGs) associated with ASP and chondrogenic differentiation.

RESULT

Surface markers of isolated rat-derived ADSCs were identified by CD44+CD90+CD45-CD106-, and exhibited the capacity for lipogenic, osteogenic, and chondrogenic differentiation. With increasing concentration of ASP treatment, there was an upregulation in the activity and acidic mucosubstance of ADSCs. The levels of Aggrecan, COL2A1, and Sox9 showed an increase in ADSCs after 28 days of 80 µg/ml ASP treatment. Transcriptome sequencing revealed that ASP-associated DEGs regulate extracellular matrix synthesis, immune response, inflammatory response, and cell cycle, and are involved in the NF-κB, AGE-RAGE, and calcium pathways. Moreover, Edn1, Frzb, Mdk, Nog, and Sulf1 are hub genes in DEGs. Notably, ASP upregulated MDK levels in ADSCs, while knockdown of MDK mitigated ASP-induced elevations in acidic mucosubstance, chondrogenic differentiation-related markers (Aggrecan, COL2A1, and Sox9), and the activity of the PI3K/AKT pathway.

CONCLUSION

ASP enhances the proliferation and chondrogenic differentiation of ADSCs by activating the MDK-mediated PI3K/AKT pathway.

Donor Sex and Passage Conditions Influence MSC Osteogenic Response in Mineralized Collagen Scaffolds

Contemporary tissue engineering efforts often seek to use mesenchymal stem cells (MSCs) due to their multi-potent potential and ability to generate a pro-regenerative secretome. While many have reported the influence of matrix environment on MSC osteogenic response, few have investigated the effects of donor and sex. Here, a well-defined mineralized collagen scaffold is used to study the influence of passage number and donor-reported sex on MSC proliferation and osteogenic potential. A library of bone marrow and adipose tissue-derived stem cells from eight donors to examine donor viability in osteogenic capacity in mineralized collagen scaffolds is obtained. MSCs displayed reduced proliferative capacity as a function of passage duration. Further, MSCs showed significant sex-associated variability in osteogenic capacity. Notably, MSCs from male donors displayed significantly higher cell proliferation while MSCs from female donors displayed significantly higher osteogenic response via increased alkaline phosphate activity, osteoprotegerin release, and mineral formation in vitro. The study highlights the essentiality of including donor-reported sex as an experimental variable and reporting culture expansion in future studies of biomaterial regenerative potential.

Photo-Clickable Triazine-Trione Thermosets as Promising 3D Scaffolds for Tissue Engineering Applications

There is an overwhelming demand for new scaffolding materials for tissue engineering (TE) purposes. Polymeric scaffolds have been explored as TE materials; however, their high glass transition state (Tg) limits their applicability. In this study, a novel materials platform for fabricating TE scaffolds is proposed based on solvent-free two-component heterocyclic triazine-trione (TATO) formulations, which cure at room temperature via thiol-ene/yne photochemistry. Three ester-containing thermosets, TATO-1, TATO-2, and TATO-3, are used for the fabrication of TE scaffolds including rigid discs, elastic films, microporous sponges, and 3D printed objects. After 14 days' incubation the materials covered a wide range of properties, from the soft TATO-2 having a compression modulus of 19.3 MPa and a Tg of 30.4 °C to the hard TATO-3 having a compression modulus of 411 MPa and a Tg of 62.5 °C. All materials exhibit micro- and nano-surface morphologies suited for bone tissue engineering, and in vitro studies found them all to be cytocompatible, supporting fast cell proliferation while minimizing cell apoptosis and necrosis. Moreover, bone marrow-derived mesenchymal stem cells on the surface of the materials are successfully differentiated into osteoblasts, adipocytes, and neuronal cells, underlining the broad potential for the biofabrication of TATO materials for TE clinical applications.

How to enhance MSCs therapeutic properties? An insight on potentiation methods

Mesenchymal stem/stromal cells (MSCs) have emerged as a promising tool in the field of regenerative medicine due to their unique therapeutic properties as they can differentiate into multiple cell types and exert paracrine effects. However, despite encouraging results obtained in preclinical studies, clinical trials have not achieved the same levels of efficacy. To improve the therapeutic properties of MSCs, several strategies have been explored. Therefore, in this review, the therapeutic properties of MSCs will be analyzed, and an update and overview of the most prominent approaches used to enhance their therapeutic capabilities will be provided. These approaches include using drugs, molecules, strategies based on biomaterials, and modification parameters in culture. The strategy described shows several common factors among those affected by these strategies that lead to an enhancement of the MSCs therapeutic properties such as the activation of the PI3K/AKT pathway and the increased expression of Heat Shock Proteins and Hypoxia-Inducible Factor. The combined effect of these elements shift MSCs towards a glycolytic state, suggesting this shift is essential for their enhancement.

Hyaluronic acid methacryloyl/chitosan methacryloyl/3-methacrylamidophenylboronic acid multifunctional hydrogel loading exosome for diabetic wound healing

The management of diabetic wounds presents a formidable challenge in clinical settings due to elevated glucose levels, drug-resistant bacterial infections, and a deficiency of bioactive molecules in the microenvironment. To address this challenge, a glucose-responsive Hyaluronic acid Methacryloyl (HAMA)-Chitosan Methacryloyl (CSMA)-3-Methacrylamidophenylboronic acid (MPBA) loading Exosome (H-C-M@Exo) multifunctional hydrogel has been developed to enhance diabetic wound healing in this study. The H-C-M@Exo hydrogel exhibits remarkable features, including high hydrophilicity, excellent pressure resistance, antibacterial properties, and good biocompatibility. It uniquely possesses the ability to sustain the release of exosomes in response to glucose fluctuations. The H-C-M@Exo hydrogel can effectively reduce inflammation, significantly promote rapid re-epithelization, facilitate favorable collagen deposition, and stimulate abundant angiogenesis at the wound sites. Furthermore, the hydrogel induces localized regulation of M2 macrophage polarization, synergistically promoting diabetic angiogenesis and wound healing. These findings suggest H-C-M@Exo hydrogel is a promising biomaterial for the treatment of chronic diabetic wounds.

Electrical signature of heterogeneous human mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) have gained traction in transplantation therapy due to their immunomodulatory, paracrine, immune-evasive, and multipotent differentiation potential. The inherent heterogeneity of hMSCs poses a challenge for therapeutic treatments and necessitates the identification of robust biomarkers to ensure reproducibility in both in vivo and in vitro experiments. In this study, we utilized dielectrophoresis (DEP), a label-free electrokinetic phenomenon, to investigate the heterogeneity of hMSCs derived from bone marrow (BM) and adipose tissue (AD). The electrical properties of BM-hMSCs were compared to homogeneous mouse fibroblasts (NIH-3T3), human fibroblasts (WS1), and human embryonic kidney cells (HEK-293). The DEP profile of BM-hMSCs differed most from HEK-293 cells. We compared the DEP profiles of BM-hMSCs and AD-hMSCs and found that they have similar membrane capacitances, differing cytoplasm conductivity, and transient slopes. Inducing both populations to differentiate into adipocyte and osteoblast cells revealed that they behave differently in response to differentiation-inducing cytokines. Histology and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analyses of the differentiation-related genes revealed differences in heterogeneity between BM-hMSCs and AD-hMSCs. The differentiation profiles correlate well with the DEP profiles developed and indicate differences in the heterogeneity of BM-hMSCs and AD-hMSCs. Our results demonstrate that using DEP, membrane capacitance, cytoplasm conductivity, and transient slope can uniquely characterize the inherent heterogeneity of hMSCs to guide robust and reproducible stem cell transplantation therapies.

The role of cells and their derivatives in otorhinolaryngologic diseases treatment

Otolaryngology is an important specialty in the field of surgery that deals with the diagnosis and treatment of the ear, nose, throat, trachea, as well as related anatomical structures. Various otolaryngological disorders are difficult to treat using established pharmacological and surgical approaches. The advent of molecular and cellular therapies led to further progress in this respect. This article reviews the therapeutic strategies of using stem cells, immune cells, and chondrocytes in otorhinolaryngology. As the most widely recognized cell derivatives, exosomes were also systematically reviewed for their therapeutic potential in head and neck cancer, otitis media, and allergic rhinitis. Finally, we summarize the limitations of stem cells, chondrocytes, and exosomes, as well as possible solutions, and provide an outlook on the future direction of cell- and derivative-based therapies in otorhinolaryngology, to offer a theoretical foundation for the clinical translation of this therapeutic modality.

Mesenchymal stem cells derived from human adipose tissue exhibit significantly higher chondrogenic differentiation potential compared to those from rats

BACKGROUND

Osteoarthritis is a prevalent joint disease affecting both humans and animals. It is characterized by articular cartilage degeneration and joint surface eburnation. Currently, no effective pharmacological treatment is available to restore the original function and structure of defective cartilage.

OBJECTIVE

This study explores the potential of stem cell-based therapy in treating joint diseases involving cartilage degeneration, offering a promising avenue for future research and treatment. The primary aim was to compare the characteristics and, more importantly, the chondrogenic differentiation potential of human and rat adipose-derived mesenchymal stem cells (AD-MSCs).

METHODS

Rat adipose tissue was collected from Sprague Dawley rats, while human adipose tissue was obtained in the form of lipoaspirate. The mesenchymal stem cells (MSCs) were then harvested using collagenase enzyme and subcultured. We meticulously evaluated and compared the cell morphology, percentage of cell viability, population doubling time, metabolic proliferation, and chondrogenic differentiation potential of MSCs harvested from both sources. Chondrogenic differentiation was induced at passage 3 using the 3D pellet culture method and assessed through histological and molecular analysis.

RESULTS

The findings revealed that human and rat AD-MSCs were phenotypically identical, and an insignificant difference was found in cell morphology, percentage of cell viability, metabolic proliferation, and population doubling time. However, the chondrogenic differentiation potential of human AD-MSCs was evaluated as significantly higher than that of rat AD-MSCs.

CONCLUSION

The current study suggests that research regarding chondrogenic differentiation of rat AD-MSCs can be effectively translated to humans. This discovery is a significant contribution to the field of regenerative medicine and has the potential to advance our understanding of stem cell-based therapy for joint diseases.

Genetic deletion of ITIH5 leads to increased development of adipose tissue in mice

BACKGROUND

Adipocytokines play a pivotal role in maintaining adipose tissue homeostasis by regulating cellular metabolism, proliferation, differentiation, and secretory activity. These soluble factors are relevant components for healthy adipose tissue, while their deficiency is closely associated with the development of obesity and related metabolic diseases, e.g., chronic inflammation. In human adipose tissue, inter-α-trypsin inhibitor heavy chain 5 (ITIH5) is expressed in proportion to the development of adipose tissue, i.e., the individual's BMI. Thus, ITIH5 has been proposed to be an inert marker of human obesity. However, when applied to adipose stem cells in vitro, recombinant (r)ITIH5 protein inhibited proliferation and adipogenesis, suggesting that ITIH5 negatively affects the development of fat mass. We now tested the role of ITIH5 in vivo and compared ITIH5+/+ wildtype with ITIH5-/- knockout mice.

RESULTS

Genetic deletion of ITIH5 significantly increased adipose tissue mass relative to animal bodyweight (p < 0.05). Next, we characterized adipose stem cells (ASCs) from both genotypes in vitro. ITIH5-/- cells exhibited increased proliferation and adipogenic differentiation (p < 0.001), which could explain the increase in adipose tissue in vivo. Furthermore, ASCs from ITIH5-/- animals were more responsive to stimulation with inflammatory mediators, i.e., these cells released greater amounts of IL-6 and MCP-1 (p < 0.001). Importantly, the application of the rITIH5 protein reversed the observed knockout effects in ASCs.

CONCLUSIONS

Our data suggest that ITIH5 potently regulates adipose tissue development and homeostasis by modulating ASC biology in mice. In addition, the effect of the rITIH5 protein underscores its potential as a therapeutic agent to correct the adipose tissue dysregulation often associated with obesity and metabolic disorders.

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

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

Lamc1 promotes osteogenic differentiation and inhibits adipogenic differentiation of bone marrow-derived mesenchymal stem cells

Bone marrow-derived mesenchymal stem cells (BMSCs) exhibit multi-lineage differentiation potential and robust proliferative capacity. The late stage of differentiation signifies the functional maturation and characterization of specific cell lineages, which is crucial for studying lineage-specific differentiation mechanisms. However, the molecular processes governing late-stage BMSC differentiation remain poorly understood. This study aimed to elucidate the key biological processes involved in late-stage BMSC differentiation. Publicly available transcriptomic data from human BMSCs were analyzed after approximately 14 days of osteogenic, adipogenic, and chondrogenic differentiation. Thirty-one differentially expressed genes (DEGs) associated with differentiation were identified. Pathway enrichment analysis indicated that the DEGs were involved in extracellular matrix (ECM)-receptor interactions, focal adhesion, and glycolipid biosynthesis, a ganglion series process. Subsequently, the target genes were validated using publicly available single-cell RNA-seq data from mouse BMSCs. Lamc1 exhibited predominant distribution in adipocytes and osteoblasts, primarily during the G2/M phase. Tln2 and Hexb were expressed in chondroblasts, osteoblasts, and adipocytes, while St3gal5 was abundantly distributed in stem cells. Cell communication analysis identified two receptors that interact with LAMCI. q-PCR results confirmed the upregulation of Lamc1, Tln2, Hexb, and St3gal5 during osteogenic differentiation and their downregulation during adipogenic differentiation. Knockdown of Lamc1 inhibited adipogenic and osteogenic differentiation. In conclusion, this study identified four genes, Lamc1, Tln2, Hexb, and St3gal5, that may play important roles in the late-stage differentiation of BMSCs. It elucidated their interactions and the pathways they influence, providing a foundation for further research on BMSC differentiation.

The Myofibroblast Fate of Therapeutic Mesenchymal Stromal Cells: Regeneration, Repair, or Despair?

Mesenchymal stromal cells (MSCs) can be isolated from various tissues of healthy or patient donors to be retransplanted in cell therapies. Because the number of MSCs obtained from biopsies is typically too low for direct clinical application, MSC expansion in cell culture is required. However, ex vivo amplification often reduces the desired MSC regenerative potential and enhances undesired traits, such as activation into fibrogenic myofibroblasts. Transiently activated myofibroblasts restore tissue integrity after organ injury by producing and contracting extracellular matrix into scar tissue. In contrast, persistent myofibroblasts cause excessive scarring-called fibrosis-that destroys organ function. In this review, we focus on the relevance and molecular mechanisms of myofibroblast activation upon contact with stiff cell culture plastic or recipient scar tissue, such as hypertrophic scars of large skin burns. We discuss cell mechanoperception mechanisms such as integrins and stretch-activated channels, mechanotransduction through the contractile actin cytoskeleton, and conversion of mechanical signals into transcriptional programs via mechanosensitive co-transcription factors, such as YAP, TAZ, and MRTF. We further elaborate how prolonged mechanical stress can create persistent myofibroblast memory by direct mechanotransduction to the nucleus that can evoke lasting epigenetic modifications at the DNA level, such as histone methylation and acetylation. We conclude by projecting how cell culture mechanics can be modulated to generate MSCs, which epigenetically protected against myofibroblast activation and transport desired regeneration potential to the recipient tissue environment in clinical therapies.

Extracellular Vesicles from Adipose Tissue-Derived Stromal Cells Stimulate Angiogenesis in a Scaffold-Dependent Fashion

BACKGROUND

The extracellular vesicles (EVs) secreted by adipose tissue-derived stromal cells (ASC) are microenvironment modulators in tissue regeneration by releasing their molecular cargo, including miRNAs. However, the influence of ASC-derived extracellular vesicles (ASC-EVs) on endothelial cells (ECs) and vascularisation is poorly understood. The present study aimed to determine the pro-angiogenic effects of ASC-EVs and explore their miRNA profile.

METHODS

EVs were isolated from normoxic and hypoxic cultured ASC conditioned culture medium. The miRNA expression profile was determined by miRseq, and EV markers were determined by Western blot and immunofluorescence staining. The uptake dynamics of fluorescently labelled EVs were monitored for 24 h. ASC-EVs' pro-angiogenic effect was assessed by sprouting ex vivo rat aorta rings in left ventricular-decellularized extracellular matrix (LV dECM) hydrogel or basement membrane hydrogel (Geltrex®).

RESULTS

ASC-EVs augmented vascular network formation by aorta rings. The vascular network topology and stability were influenced in a hydrogel scaffold-dependent fashion. The ASC-EVs were enriched for several miRNA families/clusters, including Let-7 and miR-23/27/24. The miRNA-1290 was the highest enriched non-clustered miRNA, accounting for almost 20% of all reads in hypoxia EVs.

CONCLUSION

Our study revealed that ASC-EVs augment in vitro and ex vivo vascularisation, likely due to the enriched pro-angiogenic miRNAs in EVs, particularly miR-1290. Our results show promise for regenerative and revascularisation therapies based on ASC-EV-loaded ECM hydrogels.

Mesenchymal Stromal Cells for the Enhancement of Surgical Flexor Tendon Repair in Animal Models: A Systematic Review and Meta-Analysis

Flexor tendon lacerations are primarily treated by surgical repair. Limited intrinsic healing ability means the repair site can remain weak. Furthermore, adhesion formation may reduce range of motion post-operatively. Mesenchymal stromal cells (MSCs) have been trialled for repair and regeneration of multiple musculoskeletal structures. Our goal was to determine the efficacy of MSCs in enhancing the biomechanical properties of surgically repaired flexor tendons. A PRISMA systematic review was conducted using four databases (PubMed, Ovid, Web of Science, and CINAHL) to identify studies using MSCs to augment surgical repair of flexor tendon injuries in animals compared to surgical repair alone. Nine studies were included, which investigated either bone marrow- or adipose-derived MSCs. Results of biomechanical testing were extracted and meta-analyses were performed regarding the maximum load, friction and properties relating to viscoelastic behaviour. There was no significant difference in maximum load at final follow-up. However, friction, a surrogate measure of adhesions, was significantly reduced following the application of MSCs (p = 0.04). Other properties showed variable results and dissipation of the therapeutic benefits of MSCs over time. In conclusion, MSCs reduce adhesion formation following tendon injury. This may result from their immunomodulatory function, dampening the inflammatory response. However, this may come at the cost of favourable healing which will restore the tendon's viscoelastic properties. The short duration of some improvements may reflect MSCs' limited survival or poor retention. Further investigation is needed to clarify the effect of MSC therapy and optimise its duration of action.

Role of Adipose-Derived Mesenchymal Stem Cells in Bone Regeneration

Bone regeneration involves multiple factors such as tissue interactions, an inflammatory response, and vessel formation. In the event of diseases, old age, lifestyle, or trauma, bone regeneration can be impaired which could result in a prolonged healing duration or requiring an external intervention for repair. Currently, bone grafts hold the golden standard for bone regeneration. However, several limitations hinder its clinical applications, e.g., donor site morbidity, an insufficient tissue volume, and uncertain post-operative outcomes. Bone tissue engineering, involving stem cells seeded onto scaffolds, has thus been a promising treatment alternative for bone regeneration. Adipose-derived mesenchymal stem cells (AD-MSCs) are known to hold therapeutic value for the treatment of various clinical conditions and have displayed feasibility and significant effectiveness due to their ease of isolation, non-invasive, abundance in quantity, and osteogenic capacity. Notably, in vitro studies showed AD-MSCs holding a high proliferation capacity, multi-differentiation potential through the release of a variety of factors, and extracellular vesicles, allowing them to repair damaged tissues. In vivo and clinical studies showed AD-MSCs favoring better vascularization and the integration of the scaffolds, while the presence of scaffolds has enhanced the osteogenesis potential of AD-MSCs, thus yielding optimal bone formation outcomes. Effective bone regeneration requires the interplay of both AD-MSCs and scaffolds (material, pore size) to improve the osteogenic and vasculogenic capacity. This review presents the advances and applications of AD-MSCs for bone regeneration and bone tissue engineering, focusing on the in vitro, in vivo, and clinical studies involving AD-MSCs for bone tissue engineering.

Stem Cells and Acellular Preparations in Bone Regeneration/Fracture Healing: Current Therapies and Future Directions

Bone/fracture healing is a complex process with different steps and four basic tissue layers being affected: cortical bone, periosteum, fascial tissue surrounding the fracture, and bone marrow. Stem cells and their derivatives, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, hematopoietic stem cells, skeletal stem cells, and multipotent stem cells, can function to artificially introduce highly regenerative cells into decrepit biological tissues and augment the healing process at the tissue level. Stem cells are molecularly and functionally indistinguishable from standard human tissues. The widespread appeal of stem cell therapy lies in its potential benefits as a therapeutic technology that, if harnessed, can be applied in clinical settings. This review aims to establish the molecular pathophysiology of bone healing and the current stem cell interventions that disrupt or augment the bone healing process and, finally, considers the future direction/therapeutic options related to stem cells and bone healing.

The Efficacy of Bone Marrow Stem Cell Therapy in Hip Osteoarthritis: A Scoping Review

Background

Hip osteoarthritis (HOA) is a prevalent degenerative joint disease with various treatment approaches. Biological agents, such as bone-marrow derived stem cells (BM-MSC) therapy, have recently been proposed as a treatment option in the management of HOA.

Purpose

We sought to further analyze the use of BM-MSC therapy by investigating the following questions. What is the standard preparation and practice? Does a dose response exist between stem cell therapy and clinical outcome? Does BM-MSC therapy alone produce effective clinical outcomes?

Methods

We conducted a scoping review using the Methodological Expectations of Cochrane Intervention Reviews Manual and the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines for scoping reviews. A comprehensive search of PubMed, Embase, Cochrane CENTRAL, Scopus, SPORTDiscus, Cumulative Index to Nursing and Allied Health Literature, and Web of Science Core Collection was performed in June 2023 of studies using exclusively BM-MSC injections for the treatment of HOA. Study characteristic, injection preparation and dosage, clinical outcome measures, and adverse effect data were extracted and interpreted by 3 reviewers.

Results

Seven studies with a total of 72 patients met the inclusion criteria. Clinical outcome following intra-articular injection of BM-MSCs was measured using the numerical pain scale, the Western Ontario and McMaster Universities Osteoarthritis Index, the visual analogue scale, and other scores, all of which showed reduction in pain and increase in functional ability across studies.

Conclusions

This scoping review found that the efficacy of BM-MSC therapy alone in the treatment of HOA appeared beneficial, improving clinical outcomes in each study. All 7 studies used "low-dose" injections with variable follow-up times; thus, a clear dose-response relationship cannot be drawn. Future studies using high doses and analyzing long-term effects of BM-MSC injections in HOA are needed.

Specific Features of the Functional Activity of Human Adipose Stromal Cells in the Structure of a Partial Skin-Equivalent

Mesenchymal adipose stromal cells (ASCs) are considered the most promising and accessible material for translational medicine. ASCs can be used independently or within the structure of scaffold-based constructs, as these not only ensure mechanical support, but can also optimize conditions for cell activity, as specific features of the scaffold structure have an impact on the vital activity of the cells. This manuscript presents a study of the secretion and accumulation that occur in a conditioned medium during the cultivation of human ASCs within the structure of such a partial skin-equivalent that is in contact with it. It is demonstrated that the ASCs retain their functional activity during cultivation both within this partial skin-equivalent structure and, separately, on plastic substrates: they proliferate and secrete various proteins that can then accumulate in the conditioned media. Our comparative study of changes in the conditioned media during cultivation of ASCs on plastic and within the partial skin-equivalent structure reveals the different dynamics of the release and accumulation of such secretory factors in the media under a variety of conditions of cell functioning. It is also demonstrated that the optimal markers for assessment of the ASCs' secretory functions in the studied partial skin-equivalent structure are the trophic factors VEGF-A, HGF, MCP, SDF-1α, IL-6 and IL-8. The results will help with the development of an algorithm for preclinical studies of this skin-equivalent in vitro and may be useful in studying various other complex constructs that include ASCs.

Correlation between Ca Release and Osteoconduction by 3D-Printed Hydroxyapatite-Based Templates

The application of hydroxyapatite (HA)-based templates is quite often seen in bone tissue engineering since that HA is an osteoconductive bioceramic material, which mimics the inorganic component of mineralized tissues. However, the reported osteoconductivity varies in vitro and in vivo, and the levels of calcium (Ca) release most favorable to osteoconduction have yet to be determined. In this study, HA-based templates were fabricated by melt-extrusion 3D-printing and characterized in order to determine a possible correlation between Ca release and osteoconduction. The HA-based templates were blended with poly(lactide-co-trimethylene carbonate) (PLATMC) at three different HA ratios: 10, 30, and 50%. The printability and physical properties of the HA templates were compared with those of pristine PLATMC. In vitro, osteoconductivity was assessed using seeded human bone marrow-derived mesenchymal stem cells. A mild rate of Ca release was observed for HA10 templates, which exhibited higher mineralized extracellular matrix (ECM) secretion than PLATMC at 14 and 21 days. In contrast, the high rate of Ca release exhibited by HA30 and HA50 templates was associated with reduced osteoconduction and impeded mineralized ECM secretion in vitro. Similar results were observed in vivo. In the calvarial defect model in rabbit, PLATMC and HA10 templates exhibited the highest amount of new bone formation, with obvious contact osteogenesis on their surfaces. In contrast, HA30 and HA50 exhibited distant osteogenesis and reduced amounts of new bone ingrowth. It is concluded that HA-based templates are osteoconductive only at low rates of Ca release.

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.

Understanding molecular characteristics of extracellular vesicles derived from different types of mesenchymal stem cells for therapeutic translation

Mesenchymal stem cells (MSCs) have been studied for decades as candidates for cellular therapy, and their secretome, including secreted extracellular vesicles (EVs), has been identified to contribute significantly to regenerative and reparative functions. Emerging evidence has suggested that MSC-EVs alone, could be used as therapeutics that emulate the biological function of MSCs. However, just as with MSCs, MSC-EVs have been shown to vary in composition, depending on the tissue source of the MSCs as well as the protocols employed in culturing the MSCs and obtaining the EVs. Therefore, the importance of careful choice of cell sources and culture environments is receiving increasing attention. Many factors contribute to the therapeutic potential of MSC-EVs, including the source tissue, isolation technique, and culturing conditions. This review illustrates the molecular landscape of EVs derived from different types of MSC cells along with culture strategies. A thorough analysis of publicly available omic datasets was performed to advance the precision understanding of MSC-EVs with unique tissue source-dependent molecular characteristics. The tissue-specific protein and miRNA-driven Reactome ontology analysis was used to reveal distinct patterns of top Reactome ontology pathways across adipose, bone marrow, and umbilical MSC-EVs. Moreover, a meta-analysis assisted by an AI technique was used to analyze the published literature, providing insights into the therapeutic translation of MSC-EVs based on their source tissues.

Recent advancements in cartilage tissue engineering innovation and translation

Articular cartilage was expected to be one of the first successfully engineered tissues, but today, cartilage repair products are few and they exhibit considerable limitations. For example, of the cell-based products that are available globally, only one is marketed for non-knee indications, none are indicated for severe osteoarthritis or rheumatoid arthritis, and only one is approved for marketing in the USA. However, advances in cartilage tissue engineering might now finally lead to the development of new cartilage repair products. To understand the potential in this field, it helps to consider the current landscape of tissue-engineered products for articular cartilage repair and particularly cell-based therapies. Advances relating to cell sources, bioactive stimuli and scaffold or scaffold-free approaches should now contribute to progress in therapeutic development. Engineering for an inflammatory environment is required because of the need for implants to withstand immune challenge within joints affected by osteoarthritis or rheumatoid arthritis. Bringing additional cartilage repair products to the market will require an understanding of the translational vector for their commercialization. Advances thus far can facilitate the future translation of engineered cartilage products to benefit the millions of patients who suffer from cartilage injuries and arthritides.

Comparison of different sources of mesenchymal stem cells: focus on inflammatory bowel disease

Inflammatory bowel disease (IBD) poses a significant challenge in modern medicine, with conventional treatments limited by efficacy and associated side effects, necessitating innovative therapeutic approaches. Mesenchymal stem cells (MSC) have emerged as promising candidates for IBD treatment due to their immunomodulatory properties and regenerative potential. This thesis aims to explore and compare various sources of MSC and evaluate their efficacy in treating IBD. This study comprehensively analyses MSC derived from multiple sources, including bone marrow, adipose tissue, umbilical cord, and other potential reservoirs. Core elements of this investigation include assessing differences in cell acquisition, immunomodulatory effects, and differentiation capabilities among these MSC sources, as well as comparing their clinical trial outcomes in IBD patients to their therapeutic efficacy in animal models. Through meticulous evaluation and comparative analysis, this thesis aims to elucidate disparities in the efficacy of different MSC sources for IBD treatment, thereby identifying the most promising therapeutic applications. The findings of this study are intended to advance our understanding of MSC biology and offer valuable insights for selecting the most effective MSC sources for personalized IBD therapy. Ultimately, this research endeavor will optimise therapeutic strategies for managing inflammatory bowel disease through the utilization of MSC.

M2 macrophage-derived TGF-β induces age-associated loss of adipogenesis through progenitor cell senescence

OBJECTIVES

Adipose tissue is an endocrine and energy storage organ composed of several different cell types, including mature adipocytes, stromal cells, endothelial cells, and a variety of immune cells. Adipose tissue aging contributes to the pathogenesis of metabolic dysfunction and is likely induced by crosstalk between adipose progenitor cells (APCs) and immune cells, but the underlying molecular mechanisms remain largely unknown. In this study, we revealed the biological role of p16high senescent APCs, and investigated the crosstalk between each cell type in the aged white adipose tissue.

METHODS

We performed the single-cell RNA sequencing (scRNA-seq) analysis on the p16high adipose cells sorted from aged p16-CreERT2/Rosa26-LSL-tdTomato mice. We also performed the time serial analysis on the age-dependent bulk RNA-seq datasets of human and mouse white adipose tissues to infer the transcriptome alteration of adipogenic potential within aging.

RESULTS

We show that M2 macrophage-derived TGF-β induces APCs senescence which impairs adipogenesis in vivo. p16high senescent APCs increase with age and show loss of adipogenic potential. The ligand-receptor interaction analysis reveals that M2 macrophages are the donors for TGF-β and the senescent APCs are the recipients. Indeed, treatment of APCs with TGF-β1 induces senescent phenotypes through mitochondrial ROS-mediated DNA damage in vitro. TGF-β1 injection into gonadal white adipose tissue (gWAT) suppresses adipogenic potential and induces fibrotic genes as well as p16 in APCs. A gWAT atrophy is observed in cancer cachexia by APCs senescence, whose induction appeared to be independent of TGF-β induction.

CONCLUSIONS

Our results suggest that M2 macrophage-derived TGF-β induces age-related lipodystrophy by APCs senescence. The TGF-β treatment induced DNA damage, mitochondrial ROS, and finally cellular senescence in APCs.

Mesenchymal stem cells for cartilage regeneration: Insights into molecular mechanism and therapeutic strategies

The use of mesenchymal stem cells (MSCs) in cartilage regeneration has gained significant attention in regenerative medicine. This paper reviews the molecular mechanisms underlying MSC-based cartilage regeneration and explores various therapeutic strategies to enhance the efficacy of MSCs in this context. MSCs exhibit multipotent capabilities and can differentiate into various cell lineages under specific microenvironmental cues. Chondrogenic differentiation, a complex process involving signaling pathways, transcription factors, and growth factors, plays a pivotal role in the successful regeneration of cartilage tissue. The chondrogenic differentiation of MSCs is tightly regulated by growth factors and signaling pathways such as TGF-β, BMP, Wnt/β-catenin, RhoA/ROCK, NOTCH, and IHH (Indian hedgehog). Understanding the intricate balance between these pathways is crucial for directing lineage-specific differentiation and preventing undesirable chondrocyte hypertrophy. Additionally, paracrine effects of MSCs, mediated by the secretion of bioactive factors, contribute significantly to immunomodulation, recruitment of endogenous stem cells, and maintenance of chondrocyte phenotype. Pre-treatment strategies utilized to potentiate MSCs, such as hypoxic conditions, low-intensity ultrasound, kartogenin treatment, and gene editing, are also discussed for their potential to enhance MSC survival, differentiation, and paracrine effects. In conclusion, this paper provides a comprehensive overview of the molecular mechanisms involved in MSC-based cartilage regeneration and outlines promising therapeutic strategies. The insights presented contribute to the ongoing efforts in optimizing MSC-based therapies for effective cartilage repair.

Multilineage-differentiating stress-enduring cells: a powerful tool for tissue damage repair

Multilineage-differentiating stress-enduring (Muse) cells are a type of pluripotent cell with unique characteristics such as non-tumorigenic and pluripotent differentiation ability. After homing, Muse cells spontaneously differentiate into tissue component cells and supplement damaged/lost cells to participate in tissue repair. Importantly, Muse cells can survive in injured tissue for an extended period, stabilizing and promoting tissue repair. In addition, it has been confirmed that injection of exogenous Muse cells exerts anti-inflammatory, anti-apoptosis, anti-fibrosis, immunomodulatory, and paracrine protective effects in vivo. The discovery of Muse cells is an important breakthrough in the field of regenerative medicine. The article provides a comprehensive review of the characteristics, sources, and potential mechanisms of Muse cells for tissue repair and regeneration. This review serves as a foundation for the further utilization of Muse cells as a key clinical tool in regenerative medicine.

Towards Stem Cell Therapy for Critical-Sized Segmental Bone Defects: Current Trends and Challenges on the Path to Clinical Translation

The management and reconstruction of critical-sized segmental bone defects remain a major clinical challenge for orthopaedic clinicians and surgeons. In particular, regenerative medicine approaches that involve incorporating stem cells within tissue engineering scaffolds have great promise for fracture management. This narrative review focuses on the primary components of bone tissue engineering-stem cells, scaffolds, the microenvironment, and vascularisation-addressing current advances and translational and regulatory challenges in the current landscape of stem cell therapy for critical-sized bone defects. To comprehensively explore this research area and offer insights for future treatment options in orthopaedic surgery, we have examined the latest developments and advancements in bone tissue engineering, focusing on those of clinical relevance in recent years. Finally, we present a forward-looking perspective on using stem cells in bone tissue engineering for critical-sized segmental bone defects.

Possibilities and efficiency of MSC co-transfection for gene therapy

Mesenchymal stem/stromal cells (MSCs) are not only capable of self-renewal, trans-differentiation, homing to damaged tissue sites and immunomodulation by secretion of trophic factors but are also easy to isolate and expand. Because of these characteristics, they are used in numerous clinical trials for cell therapy including immune and neurological disorders, diabetes, bone and cartilage diseases and myocardial infarction. However, not all trials have successful outcomes, due to unfavourable microenvironmental factors and the heterogenous nature of MSCs. Therefore, genetic manipulation of MSCs can increase their prospect. Currently, most studies focus on single transfection with one gene. Even though the introduction of more than one gene increases the complexity, it also increases the effectivity as different mechanism are triggered, leading to a synergistic effect. In this review we focus on the methodology and efficiency of co-transfection, as well as the opportunities and pitfalls of these genetically engineered cells for therapy.

Human bone marrow mesenchymal stem cell-driven LncRNA PTCSC3 upregulation within lung adenocarcinoma cells reduces erlotinib resistance by mitigating Wnt/β-Catenin pathway

lncRNA PTCSC3, which stands for Papillary Thyroid Carcinoma Susceptibility Candidate 3, has been found to play a role in various cellular processes, including cell proliferation, apoptosis, and migration, acting as either an oncogene or a tumor suppressor depending on the context. This study investigates the influence of lncRNA PTCSC3, derived from human bone marrow mesenchymal stem cell (hBMSC), on the efficacy of erlotinib (Er)-resistant lung adenocarcinoma (LUAD) cells and elucidates underlying mechanism. The hBMSCs and LUAD (PC9 and A549) cells were employed to establish an Er-resistant LUAD cell model. It was observed that exposure to hBMSCs reduced the viability of A549-Er and PC9-Er cells and increased their rate of apoptosis. Further investigations revealed that in the presence of hBMSCs-containing medium, PTCSC3 expression was significantly upregulated, concomitantly with a suppression of the Wnt/β-Catenin pathway. Conversely, silencing PTCSC3 led to enhanced A549-Er and PC9-Er activities, reduced cell apoptosis, and activated Wnt/β-Catenin pathway. The effects of PTCSC3 modulation were also examined by transfecting LUAD cells with different PTCSC3 expression vectors and treating them with XAV939, a Wnt/β-Catenin pathway inhibitor, which similarly decreased cell viability. In the rescue experiment, the effect of hBMSCs on LUAD cells could be counteracted by down-regulation of PTCSC3, and the effect of PTCSC3 down-regulation on cells was mitigated by XAV939. This study revealed that hBMSCs promote the up-regulation of PTCSC3 in LUAD cells, thus inhibiting Wnt/β-Catenin pathway and reversing Er resistance, offering a potential novel strategy to enhance the efficacy of chemotherapy in LUAD.

A comprehensive stem cell laboratory module with blended learning for medical students at Tongji University

The laboratory practice "Primary culture and directional differentiation of rat bone marrow mesenchymal stem cells (BMSCs)" is part of a required course for sophomore medical students at Tongji university, which has been conducted since 2012. Blended learning has been widely applied in medical courses. Based on a student-centered teaching philosophy, we reconstructed a comprehensive stem cell laboratory module with blended learning in 2021, aiming to facilitate students in enhancing their understanding of the multi-lineage differentiation potential of stem cells and improve their experimental skills, self-directed learning ability, and innovative thinking. First, we constructed in-depth online study resources, including videos demonstrating laboratory procedures, a PowerPoint slide deck, and published literature on student self-learning before class. In class, students performed a primary culture of BMSCs, freely chose among adipogenic, osteogenic, or chondrogenic differentiation, and used cytochemical or immunofluorescence staining for identification. After class, the extracurricular part involved performing quantitative polymerase chain reaction to examine the expression of multi-lineage differentiation marker genes, which was designed as an elective. After 2 years of practice, positive feedback was obtained from both students and faculty members who achieved, the learning goal as expected. The reconstructed stem cell laboratory module provides comprehensive practice opportunities for students. Students have a better understanding of BMSC at the molecular, cellular, and functional levels and have improved their experimental skills, which forms a basis for scientific research for medical students. Introducing blended learning into other medical laboratory practices thus seems valuable.

Effect of metabolically divergent pig breeds and tissues on mesenchymal stem cell expression patterns during adipogenesis

BACKGROUND

Unraveling the intricate and tightly regulated process of adipogenesis, involving coordinated activation of transcription factors and signaling pathways, is essential for addressing obesity and related metabolic disorders. The molecular pathways recruited by mesenchymal stem cells (MSCs) during adipogenesis are also dependent on the different sources of the cells and genetic backgrounds of donors, which contribute to the functional heterogeneity of the stem cells and consequently affect the developmental features and fate of the cells.

METHODS

In this study, the alteration of transcripts during differentiation of synovial mesenchymal stem cells (SMSCs) derived from fibrous synovium (FS) and adipose synovial tissue (FP) of two pig breeds differing in growth performance (German Landrace (DL)) and fat deposition (Angeln Saddleback (AS)) was investigated. SMSCs from both tissues and breeds were stimulated to differentiate into adipocytes in vitro and sampled at four time points (day 1, day 4, day 7 and day 14) to obtain transcriptomic data.

RESULTS

We observed numerous signaling pathways related to the cell cycle, cell division, cell migration, or cell proliferation during early stages of adipogenesis. As the differentiation process progresses, cells begin to accumulate intracellular lipid droplets and changes in gene expression patterns in particular of adipocyte-specific markers occur. PI3K-Akt signaling and metabolic pathways changed most during adipogenesis, while p53 signaling and ferroptosis were affected late in adipogenesis. When comparing MSCs from FS and FP, only a limited number of differentially expressed genes (DEGs) and enriched signaling pathways were identified. Metabolic pathways, including fat, energy or amino acid metabolism, were highly enriched in the AS breed SMSCs compared to those of the DL breed, especially at day 7 of adipogenesis, suggesting retention of the characteristic metabolic features of their original source, demonstrating donor memory in culture. In contrast, the DL SMSCs were more enriched in immune signaling pathways.

CONCLUSIONS

Our study has provided important insights into the dynamics of adipogenesis and revealed metabolic shifts in SMSCs associated with different cell sources and genetic backgrounds of donors. This emphasises the critical role of metabolic and genetic factors as important indications and criteria for donor stem cell selection.

Phenotypic and Functional Characterization of Bovine Adipose-Derived Mesenchymal Stromal Cells

BACKGROUND

Mesenchymal stem cells (MSCs) are increasingly trialed in cellular therapy applications in humans. They can also be applied to treat a range of diseases in animals, particularly in cattle to combat inflammatory conditions and aging-associated degenerative disorders. We sought to demonstrate the feasibility of obtaining MSCs from adipose tissue and characterizing them using established assays.

METHODS

Bovine adipose MSCs (BvAdMSCs) were isolated using in-house optimized tissue digestion protocols and characterized by performing a colony formation assay, cell growth assessments, cell surface marker analysis by immunocytochemistry and flow cytometry, osteogenic and adipogenic differentiation, and secretion of indoleamine 2,3-dioxygenease (IDO).

RESULTS

Our results demonstrate the feasibility of successful MSC isolation and culture expansion from bovine adipose tissues with characteristic features of colony formation, in vitro multilineage differentiation into osteogenic and adipogenic lineages, and cell surface marker expression of CD105, CD73, CD90, CD44, and CD166 with negative expression of CD45. BvAdMSCs secreted significant amounts of IDO with or without interferon-gamma stimulation, indicating ability for immunomodulation.

CONCLUSIONS

We report a viable approach to obtaining autologous adipose-derived MSCs that can be applied as potential adjuvant cell therapy for tissue repair and regeneration in cattle. Our methodology can be utilized by veterinary cell therapy labs for preparing MSCs for disease management in cattle.

The Immunomodulatory effect of exosomes in diabetes: a novel and attractive therapeutic tool in diabetes therapy

Exosomes carry proteins, metabolites, nucleic acids and lipids from their parent cell of origin. They are derived from cells through exocytosis, are ingested by target cells, and can transfer biological signals between local or distant cells. Therefore, exosomes are often modified in reaction to pathological processes, including infection, cancer, cardiovascular diseases and in response to metabolic perturbations such as obesity and diabetes, all of which involve a significant inflammatory aspect. Here, we discuss how immune cell-derived exosomes origin from neutrophils, T lymphocytes, macrophages impact on the immune reprogramming of diabetes and the associated complications. Besides, exosomes derived from stem cells and their immunomodulatory properties and anti-inflammation effect in diabetes are also reviewed. Moreover, As an important addition to previous reviews, we describes promising directions involving engineered exosomes as well as current challenges of clinical applications in diabetic therapy. Further research on exosomes will explore their potential in translational medicine and provide new avenues for the development of effective clinical diagnostics and therapeutic strategies for immunoregulation of diabetes.

BMSC-Derived Exosomes Attenuate Rat Osteoarthritis by Regulating Macrophage Polarization through PINK1/Parkin Signaling Pathway

OBJECTIVE

Exosomes derived from bone marrow mesenchymal stem cells (BMSC-Exos) may modulate the M1/M2 polarization of macrophages during osteoarthritis (OA). However, the underlying mechanisms of BMSC-Exos in this process still need to be elucidated. In this study, we explored the role of BMSC-Exos in the polarization of macrophages in vitro and the OA rats in vivo.

METHODS

The effects of BMSC-Exos on RAW264.7 cells were determined, including the production of reactive oxygen species (ROS) and the protein expression of Akt, PINK1, and Parkin. We prepared an OA model by resecting the anterior cruciate ligament and medial meniscus of Sprague-Dawley (SD) rats. Hematoxylin-eosin (H&E) and safranin O-fast green staining, immunohistochemistry and immunofluorescence analyses, and the examination of interleukin 6 (IL-6), interleukin 1β (IL-1β), tumor necrosis factor alpha (TNF-α), and interleukin 10 (IL-10) were performed to assess changes in cartilage and synovium.

RESULTS

BMSC-Exos inhibited mitochondrial membrane damage, ROS production, and the protein expression of PINK1 and Parkin. Akt phosphorylation was downregulated under lipopolysaccharide (LPS) induction but significantly recovered after treatment with BMSC-Exos. BMSC-Exos alleviated cartilage damage, inhibited M1 polarization, and promoted M2 polarization in the synovium in OA rats. The expression of PINK1 and Parkin in the synovium and the levels of IL-6, IL-1β, and TNF-α in the serum decreased, but the level of IL-10 increased when BMSC-Exos were used in OA rats.

CONCLUSION

BMSC-Exos ameliorate OA development by regulating synovial macrophage polarization, and one of the underlying mechanisms may be through inhibiting PINK1/Parkin signaling.

Recent Advances in the Use of Stem Cells in Tissue Engineering and Adjunct Therapies for Tendon Reconstruction and Future Perspectives

Due to their function, tendons are exposed to acute injuries. This type of damage to the musculoskeletal system represents a challenge for clinicians when natural regeneration and treatment methods do not produce the expected results. Currently, treatment is long and associated with long-term complications. In this review, we discuss the use of stem cells in the treatment of tendons, including how to induce appropriate cell differentiation based on gene therapy, growth factors, tissue engineering, proteins involved in regenerative process, drugs and three-dimensional (3D) structures. A multidirectional approach as well as the incorporation of novel components of the therapy will improve the techniques used and benefit patients with tendon injuries in the future.

Stem Cell-Derived Exosomes: An Advanced Horizon to Cancer Regenerative Medicine

Cancer research has made significant progress in recent years, and extracellular vesicles (EVs) based cancer investigation reveals several facts about cancer. Exosomes are a subpopulation of EVs. In the present decade, exosomes is mostly highlighted for cancer theranostic research. Tumor cell derived exosomes (TEXs) promote cancer but there are multiple sources of exosomes that can be used as cancer therapeutic agents (plant exosomes, stem cell-derived exosomes, modified or synthetic exosomes). Stem cells based regenerative medicine faces numerous challenges, such as promote tumor development, cellular reprogramming etc., and therefore addressing these complications becomes essential. Stem cell-derived exosomes serves as an answer to these problems and offers a better solution. Global research indicates that stem cell-derived exosomes also play a dual role in the cellular system by either inhibiting or promoting cancer. Modified exosomes which are genetically engineered exosomes or surface modified exosomes to increase the efficacy of the therapeutic properties can also be considered to target the above concerns. However, the difficulties associated with the exosomes include variations in exosomes heterogenity, isolation protocols, large scale production, etc., and these have to be managed effectively. In this review, we explore exosomes biogenesis, multiple stem cell-derived exosome sources, drug delivery, modified stem cells exosomes, clinical trial of stem cells exosomes, and the related challenges in this domain and future orientation. This article may encourage researchers to explore stem cell-derived exosomes and develop an effective and affordable cancer therapeutic solution.

Trends in Adipose-Derived Stem Cell-Conditioned Medium: A Bibliometric and Visualized Review

Adipose-derived stem cell-conditioned medium (ADSC-CM) has been widely studied and used as a stem cell-based cell-free therapy. Due to the explosion of scientific publications in this field, it is difficult to review all relevant publications systematically, not mention quantitively. In this study, we combined bibliometrics with the conventional review method to summarize, analyze, and visualize the characteristics of nearly all published articles related to ADSC-CM using CiteSpace-a bibliometrics software. We applied this software to quantitively and vividly show (a) annual publications and citations; (b) distributions and co-occurrence networks of countries/regions, authors, journals, and institutions; (c) keyword co-occurrence networks and clusters in different time periods; (d) cocitation networks of references; and (e) ongoing challenges and new topics in ADSC-CM. Altogether, we found that ADSC-CM is at a hot stage with an increasing number of publications and citations, extensive and close scientific collaborations, and dense cocited networks. Impact statement To our best knowledge, it is the first bibliometric and visualized review in the field of adipose-derived stem cell-conditioned medium (ADSC-CM). This review systematically and quantitatively revealed the developments, challenges, and emerging hot spots of ADSC-CM, providing a panoramic view to assist researchers to decide the direction of their future study in the fields of ADSCs and CM derived from stem cells.