Why are MSCs therapeutic? New data: new insight

The suppression of cell motility through the reduction of FAK activity and expression of cell adhesion proteins by hAMSCs secretome in MDA-MB-231 breast cancer cells

Breast cancer is a leading cause of death in women worldwide. Cancer therapy based on stem cells is considered as a novel and promising platform. In the present study, we explore the therapeutic effects of human amniotic mesenchymal stromal cells (hAMSCs) through the reduction of focal adhesion kinase (FAK) activity, SHP-2, and cell adhesion proteins such as Paxillin, Vinculin, Fibronectin, Talin, and integrin αvβ3 expression in MDA-MB-231 breast cancer cells. For this purpose, we employed a co-culture system using 6-well plate transwell. After 72 h, hAMSCs-treated MDA-MB-231 breast cancer cells, the activity of focal adhesion kinase (FAK) and the expression of SHP-2 and cell adhesion proteins such as Paxillin, Vinculin, Fibronectin, Talin, and integrin αvβ3 expression were analyzed using western blot. The shape and migration of cells were also analyzed. Based on our results, a significant reduction in tumor cell motility through downregulation of the tyrosine phosphorylation level of FAK (at Y397 and Y576/577 sites) and cell adhesion expression in MDA-MB-231 breast cancer cells was demonstrated. Our findings indicate that hAMSCS secretome has therapeutic effects on cancer cell migration through downregulation of FAK activity and expression of cell adhesion proteins.

Injection of Autologous Adipose Stromal Vascular Fraction in Combination with Autologous Conditioned Plasma for the Treatment of Advanced Knee Osteoarthritis Significantly Improves Clinical Symptoms

(1) Background: Osteoarthritis (OA) is the most common joint disease in the world. It is chronic, systemic, progressive and disabling. Orthobiologics have the potential to positively alter the course of this disease. Therefore, the aim of this study is to evaluate the efficacy of SVF/ACP in the treatment of advanced osteoarthritis of the knee in an unfiltered patient population. We hypothesize that this therapy can improve the symptoms associated with osteoarthritis of the knee. We also hypothesize that there are patient-related factors that influence the efficacy of therapy. (2) Methods: Two hundred and thirteen patients with moderate to severe OA of the knee and SVF/ACP injection were recruited for this study. Patients were excluded if they did not provide informed consent or were not receiving SVF/ACP therapy. Pain, function, symptoms and quality of life were assessed using standardized scores (KOOS, WOMAC) before and after treatment. (3) Results: The VAS pain score was significantly reduced by at least 30% (p < 0.001). Knee function, as measured by the KOOS daily activity and sport scores, showed significant increases of 21% and 45%, respectively, at 6 months (p < 0.04). (4) Conclusions: Treatment of knee OA with SVF/ACP injection positively modifies the disease by significantly reducing pain and improving function.

Stem Cell-Derived Exosomal MicroRNAs as Novel Potential Approach for Multiple Sclerosis Treatment

Multiple Sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) characterized by inflammation and demyelination of CNS neurons. Up to now, there are many therapeutic strategies for MS but they are only being able to reduce progression of diseases and have not got any effect on repair and remyelination. Stem cell therapy is an appropriate method for regeneration but has limitations and problems. So recently, researches were used of exosomes that facilitate intercellular communication and transfer cell-to-cell biological information. MicroRNAs (miRNAs) are a class of short non-coding RNAs that we can used to their dysregulation in order to diseases diagnosis. The miRNAs of microvesicles obtained stem cells may change the fate of transplanted cells based on received signals of injured regions. The miRNAs existing in MSCs may be displayed the cell type and their biological activities. Current studies show also that the miRNAs create communication between stem cells and tissue-injured cells. In the present review, firstly we discuss the role of miRNAs dysregulation in MS patients and miRNAs expression by stem cells. Finally, in this study was confirmed the relationship of microRNAs involved in MS and miRNAs expressed by stem cells and interaction between them in order to find appropriate treatment methods in future for limit to disability progression.

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

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

Intratesticular transplantation of allogenic mesenchymal stem cells mitigates testicular destruction after induced heat stress in Miniature-horse stallions

Testicular degeneration (TD) is the most frequent cause of sub or infertility in stallions. Currently, mesenchymal stem cells (MSC) have been studied as a therapeutic option for several diseases including induced-TD in laboratory animals. Therefore, this study aimed to evaluate the effect of intratesticular MSC therapy on the testicular histology of stallions submitted to scrotal heat stress. Ten healthy Miniature-horse stallions were submitted to testicular heat stress induced by a heating wrap device (42-45°C). Afterward, the stallions were divided into two groups and treated seven days later. MSCs-treated stallions were treated with an intratesticular injection of 10 × 106 of MSCs diluted in 5 mL of PBS, whereas placebo-treated stallions had 5 mL of PBS intratesticular injected. All stallions had testicular biopsies collected seven days before and one- and 14-days post-heat stress and were castrated 30 days after testicular insult. Tissue sections were stained with H&E and evaluated for the tubular and luminal diameter, epithelial thickness, seminiferous tubules (STs) integrity, the number of spermatozoa in the STs, and the percent of abnormal STs. Significance was set at P≤0.05. In both groups, testicular heat stress damaged the STs (P<0.05). However, STs' parameters were improved in MSCs-treated stallions compared to placebo-treated stallions 30 days after the testicular insult (P<0.05). In conclusion, the results of the present study suggest that intratesticular MSC therapy provided a therapeutic advantage in rescuing acute TD in stallions. However, further studies are essential to evaluate the benefits of this therapy on semen parameters and stallions with idiopathic TD.

Comparison of Periodontal Ligament Stem Cells with Mesenchymal Stem Cells from Other Sources: A Scoping Systematic Review of In vitro and In vivo Studies

OBJECTIVE

The application of stem cells in regenerative medicine depends on their biological properties. This scoping review aimed to compare the features of periodontal ligament stem cells (PDLSSCs) with stem cells derived from other sources.

DESIGN

An electronic search in PubMed/Medline, Embase, Scopus, Google Scholar and Science Direct was conducted to identify in vitro and in vivo studies limited to English language.

RESULTS

Overall, 65 articles were included. Most comparisons were made between bone marrow stem cells (BMSCs) and PDLSCs. BMSCs were found to have lower proliferation and higher osteogenesis potential in vitro and in vivo than PDLSCs; on the contrary, dental follicle stem cells and umbilical cord mesenchymal stem cells (UCMSCs) had a higher proliferative ability and lower osteogenesis than PDLSCs. Moreover, UCMSCs exhibited a higher apoptotic rate, hTERT expression, and relative telomerase length. The immunomodulatory function of adipose-derived stem cells and BMSCs was comparable to PDLSCs. Gingival mesenchymal stem cells showed less sensitivity to long-term culture. Both pure and mixed gingival cells had lower osteogenic ability compared to PDLSCs. Comparison of dental pulp stem cells (DPSCs) with PDLSCs regarding proliferation rate, osteo/adipogenesis, and immunomodulatory properties was contradictory; however, in vivo bone formation of DPSCs seemed to be lower than PDLSCs.

CONCLUSION

In light of the performed comparative studies, PDLSCs showed comparable results to stem cells derived from other sources; however, further in vivo studies are needed to determine the actual pros and cons of stem cells in comparison to each other.

Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial

Various types of cellular injection have become a popular and costly treatment option for patients with knee osteoarthritis despite a paucity of literature establishing relative efficacy to each other or corticosteroid injections. Here we aimed to identify the safety and efficacy of cell injections from autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction and allogeneic human umbilical cord tissue-derived mesenchymal stromal cells, in comparison to corticosteroid injection (CSI). The study was a phase 2/3, four-arm parallel, multicenter, single-blind, randomized, controlled clinical trial with 480 patients with a diagnosis of knee osteoarthritis (Kellgren-Lawrence II-IV). Participants were randomized to the three different arms with a 3:1 distribution. Arm 1: autologous bone marrow aspirate concentrate (n = 120), CSI (n = 40); arm 2: umbilical cord tissue-derived mesenchymal stromal cells (n = 120), CSI (n = 40); arm 3: stromal vascular fraction (n = 120), CSI (n = 40). The co-primary endpoints were the visual analog scale pain score and Knee injury and Osteoarthritis Outcome Score pain score at 12 months versus baseline. Analyses of our primary endpoints, with 440 patients, revealed that at 1 year post injection, none of the three orthobiologic injections was superior to another, or to the CSI control. In addition, none of the four groups showed a significant change in magnetic resonance imaging osteoarthritis score compared to baseline. No procedure-related serious adverse events were reported during the study period. In summary, this study shows that at 1 year post injection, there was no superior orthobiologic as compared to CSI for knee osteoarthritis. ClinicalTrials.gov Identifier: NCT03818737.

Novel cell-based strategies for immunomodulation in vascularized composite allotransplantation

PURPOSE OF REVIEW

Vascularized composite allotransplantation (VCA) has become a clinical reality in the past two decades. However, its routine clinical applications are limited by the risk of acute rejection, and the side effects of the lifelong immunosuppression. Therefore, there is a need for new protocols to induce tolerance and extend VCA survival. Cell- based therapies have emerged as an attractive strategy for tolerance induction in VCA. This manuscript reviews the current strategies and applications of cell-based therapies for tolerance induction in VCA.

RECENT FINDINGS

Cellular therapies, including the application of bone marrow cells (BMC), mesenchymal stem cells (MSC), adipose stem cells, regulatory T cells (Treg) cells, dendritic cells and donor recipient chimeric cells (DRCC) show promising potential as a strategy to induce tolerance in VCA. Ongoing basic science research aims to provide insights into the mechanisms of action, homing, functional specialization and standardization of these cellular therapies. Additionally, translational preclinical and clinical studies are underway, showing encouraging outcomes.

SUMMARY

Cellular therapies hold great potential and are supported by preclinical studies and clinical trials demonstrating safety and efficacy. However, further research is needed to develop novel cell-based immunosuppressive protocol for VCA.

Modulating Mesenchymal Stromal Cell Microenvironment Alters Exosome RNA Content and Ligament Healing Capacity

Although mesenchymal stromal cell (MSC) based therapies hold promise in regenerative medicine, their applications in clinical settings remain challenging due to issues such as immunocompatibility and cell stability. MSC-derived exosomes, small vesicles carrying various bioactive molecules, are a promising cell-free therapy to promote tissue regeneration. However, it remains unknown mainly regarding the ability to customize the content of MSC-derived exosomes, how alterations in the MSC microenvironment influence exosome content, and the effects of such modifications on healing efficiency and mechanical properties in tissue regeneration. In this study, we used an in vitro system of human MSC-derived exosomes and an in vivo rat ligament injury model to address these questions. We found a context-dependent correlation between exosomal and parent cell RNA content. Under native conditions, the correlation was moderate but heightened with microenvironmental changes. In vivo rat ligament injury model showed that MSC-derived exosomes increased ligament max load and stiffness. We also found that changes in the MSCs' microenvironment significantly influence the mechanical properties driven by exosome treatment. Additionally, a link was identified between altered exosomal microRNA levels and expression changes in microRNA targets in ligaments. These findings elucidate the nuanced interplay between MSCs, their exosomes, and tissue regeneration.

Investigation of the effects of umbilical cord-derived mesenchymal stem cells and curcumin on Achilles tendon healing - can they act synergistically?

BACKGROUND

It is known that curcumin and umbilical cord-derived mesenchymal stem cells (UC-MSCs) positively affect experi-mental tendon injury healing. This study investigated individual effects and potential synergistic effects of using curcumin and UC-MSCs alone and together.

METHODS

Eighty female Wistar albino rats were randomly divided into five groups: Control, curcumin, sesame oil, MSCs, and Curcumin+MSCs groups. In all rats, punch tendon defect was created in both right and left Achilles tendons. While no additional treatment was applied to the control group, curcumin, sesame oil used as a solvent for curcumin, MSCs, and MSCs and curcumin com-bination were applied locally to the injury site, respectively, in the other groups. Curcumin was solved in sesame oil before application. In each group, half of the animals were euthanized in the post-operative 2nd week while the other half were euthanized in the post-operative 4th week. The right Achilles was used for biomechanical testing, while the left Achilles was used for histological evaluation and immunohistochemical analysis of type I, Type III collagen, and tenomodulin.

RESULTS

Histologically, significant improvement was observed in the curcumin, MSCs, and Curcumin+ MSCs groups compared to the control Group in the 2nd week. In the 2nd and 4th weeks, Type III collagen was significantly increased in the curcumin group com-pared to the control group. In week 4, tenomodulin increased significantly in the curcumin and MSCs groups compared to the control group. Tendon tensile strength increased significantly in MSCs and Curcumin+MSCs groups compared to the control group in the 4th week. No superiority was observed between the treatment groups regarding their positive effects on recovery.

CONCLUSION

Locally used curcumin and UC-MSCs showed positive effects that were not superior to each other in the healing of injury caused by a punch in the Achilles tendons of rats. However, synergistic effects on healing were not observed when they were applied together.

The role of toll-like receptors in orchestrating osteogenic differentiation of mesenchymal stromal cells and osteoimmunology

Osteoimmunology is a concept involving molecular and cellular crosstalk between the skeletal and immune systems. Toll-like receptors (TLRs) are widely expressed both on mesenchymal stromal cells (MSCs), the hematopoietic cells, and immune cells in the osteogenic microenvironment for bone development or repair. TLRs can sense both exogenous pathogen-associated molecular patterns (PAMPs) derived from microorganisms, and damage-associated molecular patterns (DAMPs) derived from normal cells subjected to injury, inflammation, or cell apoptosis under physiological or pathological conditions. Emerging studies reported that TLR signaling plays an important role in bone remodeling by directly impacting MSC osteogenic differentiation or osteoimmunology. However, how to regulate TLR signaling is critical and remains to be elucidated to promote the osteogenic differentiation of MSCs and new bone formation for bone tissue repair. This review outlines distinct TLR variants on MSCs from various tissues, detailing the impact of TLR pathway activation or inhibition on MSC osteogenic differentiation. It also elucidates TLR pathways' interplay with osteoclasts, immune cells, and extracellular vesicles (EVs) derived from MSCs. Furthermore, we explore biomaterial-based activation to guide MSCs' osteogenic differentiation. Therefore, understanding TLRs' role in this context has significant implications for advancing bone regeneration and repair strategies.

Mesenchymal stem cell therapy in aqueous deficient dry eye disease

ENGLISH SUMMARY

Dry eye disease (DED) is characterized by ocular dryness, irritation and blurred vision and has a significant impact on the patient's quality of life. This condition can be particularly severe in patients with aqueous deficient dry eye disease (ADDE) due to Sjögren's syndrome (SS), an autoimmune disease that affects the lacrimal and salivary glands. Current treatments for ADDE are often limited to symptomatic relief. A literature review was conducted to explore the current surgical interventions used or tested in humans with ADDE (I). These interventions include procedures involving the eyelids and tear ducts, transplantation of amniotic membrane or salivary glands, injections around the tear ducts and cell-based injections into the lacrimal gland (LG). Each treatment has its advantages and disadvantages; however, treating dry eyes in patients with SS presents a particular challenge due to the systemic nature of the disease. Moreover, there is a need for new therapeutic options. Mesenchymal stem cells (MSCs) are a type of stem cell that have shown promise in regenerating damaged tissue and reducing inflammation in various diseases. Previous studies in animal models have suggested that MSCs could be effective in treating ADDE. Thus, this thesis aims to investigate the safety and efficacy of injecting MSCs into the LG as a treatment option for patients with ADDE secondary to SS. The study also aims to see this treatment in light of existing and novel investigational treatment options. The clinical studies conducted for this thesis are the first of their kind in humans. MSCs derived from healthy donors' adipose tissue (ASCs) were cultured in a laboratory, frozen and thawed ready for use. In the safety study, we performed the first human trial involving the administration of a single injection of ASCs into the LG of one eye in seven patients suffering from severe ADDE (II). The primary objective was to test the safety of this treatment, while the secondary objective was to assess improvements in subjective and objective signs of dry eye. The results of the trial showed no serious side effects within 4 months of follow-up after treatment. On average, there was a 40% reduction in dry eye symptoms assessed with the Ocular Surface Disease Index (OSDI) questionnaire. Additionally, in the treated eye, there was a significant decrease in tear osmolarity, an increase in tear film stability and an increase in tear production. To further investigate the efficacy of this treatment, our research group performed a clinical, randomized study aiming to compare the ASC injection into the LG with the injection of a vehicle (the excipient in which the ASCs are dissolved) and observation (no intervention) (III). The study involved 20 subjects receiving ASC injection, 20 subjects receiving vehicle injection and 14 patients being observed without intervention. The subjects were examined to assess the outcomes with a 12-month follow-up after treatment. Both intervention groups showed a significant reduction in subjective dry eye symptoms of approximately 40%. This improvement was evident at the 1-week follow-up and persisted until the 12-month follow-up. The observation group did not experience any change in OSDI score. The ASCs group exhibited a significant mean increase in non-invasive tear break-up time (NIKBUT) of 6.48 s (149%) at the four-week follow-up, which was significantly higher than that in the vehicle group (p = 0.04). Moreover, the ASCs group showed a significant increase in NIKBUT compared to that in the observation group at the 12-month follow-up (p = 0.004). In both the ASCs and vehicle group, a significant increase in Schirmer test scores at the 4-month follow-up and the 12-month follow-up was observed. In conclusion, this thesis contributes valuable findings with a new treatment option for patients with dry eye disease. Injection of ASCs into the LG was shown to be safe and to improve subjective dry eye symptoms and specifically the tear film stability in patients with ADDE due to SS. Compared to other treatment modalities of ADDE, this treatment has greater potential, as ASCs could potentially be used as an anti-inflammatory therapeutic option for managing DED of other causes as well. RESUMÉ (DANISH SUMMARY): Tørre øjne, karakteriseret ved tørhedsfornemmelse og irritation af øjnene samt sløret syn, har en betydelig indvirkning på patientens livskvalitet. Denne tilstand kan vaere saerligt alvorlig hos patienter med nedsat tåreproduktion (ADDE) som følge af Sjögrens syndrom (SS), en autoimmun sygdom, der påvirker tårekirtlerne og spytkirtlerne. Nuvaerende behandlinger for ADDE er ofte begraenset til symptomlindring. Vi gennemførte en litteraturgennemgang for at undersøge, hvilke nuvaerende kirurgiske behandlingsmetoder, der anvendes eller testes hos patienter med ADDE (I). Disse interventioner inkluderer procedurer, der involverer øjenlåg og tårekanaler, transplantation af amnionhinde eller spytkirtler, injektioner omkring tårekanalerne samt cellebaserede injektioner i tårekirtlen. Hver behandling har sine fordele og ulemper, men behandling af tørre øjne hos patienter med SS udgør en saerlig udfordring på grund af sygdommens systemiske udbredning, og der er behov for nye behandlingsmuligheder. Mesenkymale stamceller (MSCs) er en type stamcelle, der har vist lovende resultater med hensyn til at regenerere beskadiget vaev og reducere inflammation i forskellige sygdomme. Tidligere undersøgelser i dyremodeller har indikeret, at MSCs kan vaere en effektiv behandling af ADDE. Denne afhandling har til formål at undersøge sikkerheden og effekten af injektion af MSCs i tårekirtlen som en mulig behandling til patienter med ADDE som følge af SS. Afhandlingen sigter også mod at sammenligne denne behandling med andre eksisterende, kirurgiske behandlingsmuligheder af ADDE. Som led i dette projekt udførte vi de første kliniske forsøg af sin art i mennesker. MSCs fra raske donorers fedtvaev (ASCs) blev dyrket i et laboratorium, frosset ned og er optøet klar til brug. Det første mål var at teste sikkerheden ved denne behandling og sekundaert at undersøge behandlingens effekt. For at undersøge dette modtog syv forsøgspersoner med svaer ADDE én injektion med ASCs i tårekirtlen på det ene øje (II). Resultaterne af forsøget viste ingen alvorlige bivirkninger inden for fire måneders opfølgning efter behandlingen. I gennemsnit fandt vi yderligere en 40% reduktion i symptomer på tørre øjne vurderet med et spørgeskema, og en markant stigning i tåreproduktionen og af tårefilmens stabilitet i det behandlede øje. For yderligere at undersøge effekten af denne behandling udførte vi et klinisk, randomiseret forsøg med det formål at sammenligne injektion af ASCs i tårekirtlen med injektion af en kontrolopløsning (vaesken, hvor stamcellerne var opløst) og observation (ingen intervention) (III). Studiet omfattede 20 forsøgspersoner, der modtog ASC-injektion, 20 forsøgspersoner, der modtog injektion af kontrolopløsningen, og 14 forsøgspersoner i observationsgruppen. Forsøgspersonerne blev undersøgt med en opfølgningstid på 12 måneder efter behandling. Begge interventionsgrupper viste en betydelig reduktion på ca. 40% i subjektive symptomer på tørre øjne. Denne forbedring var betydelig allerede ved opfølgning efter en uge og varede ved 12 måneder efter behandling. Observationsgruppen oplevede ingen betydelig aendring i symptomer. ASCs gruppen viste desuden en signifikant stigning i tårefilmsstabiliteten (NIKBUT) på 6,48 sekunder (149%) ved opfølgning efter fire uger, hvilket var markant højere end efter injektion af kontrolopløsning (p = 0,04). Desuden viste ASCs gruppen en betydelig stigning i NIKBUT sammenlignet med observationsgruppen ved opfølgning efter 12 måneder (p = 0,004). Både injektion af ASCs og kontrolopløsning medførte en betydelig stigning i tåreproduktionen ved opfølgning fire måneder og 12 måneder efter behandling. Denne afhandling bidrager med vigtige resultater inden for en ny behandlingsmulighed af tørre øjne. Injektion af ASCs i tårekirtlen viste sig at vaere sikker, forbedrede subjektive symptomer på tørre øjne og øgede saerligt tårfilmens stabilitet hos patienter med ADDE på grund af SS. Sammenlignet med andre behandlingsmuligheder for ADDE har denne behandling vist et stort potentiale. ASCs kan muligvis også bruges som en anti-inflammatorisk behandling af tørre øjne af andre årsager i fremtiden.

Inflammatory diseases: Function of LncRNAs in their emergence and the role of mesenchymal stem cell secretome in their treatment

One of the best treatments for inflammatory diseases such as COVID-19, respiratory diseases and brain diseases is treatment with stem cells. Here we investigate the effect of stem cell therapy in the treatment of brain diseases.Preclinical studies have shown promising results, including improved functional recovery and tissue repair in animal models of neurodegenerative diseases, strokes,and traumatic brain injuries. However,ethical implications, safety concerns, and regulatory frameworks necessitate thorough evaluation before transitioning to clinical applications. Additionally, the complex nature of the brain and its intricate cellular environment present unique obstacles that must be overcome to ensure the successful integration and functionality of genetically engineered MSCs. The careful navigation of this path will determine whether the application of genetically engineered MSCs in brain tissue regeneration ultimately lives up to the hype surrounding it.

Isolation of Vascular Wall Mesenchymal Stem Cells from the Thoracic Aorta of Adult Göttingen Minipigs: A New Protocol for the Simultaneous Endothelial Cell Collection

Two main classes of perivascular multipotent populations have been described: the microvascular pericytes and the vascular wall mesenchymal stem cells (VW-MSCs). VW-MSCs are isolated from large vessels in many species and they participate in vascular remodeling together with other cellular components such as endothelial cells. Considering that the Göttingen Minipigs are widely used in Europe as a translational model in the field of cardiovascular diseases, the aim of the present research was to isolate VW-MSCs from the adult aorta of Göttingen Minipigs while preserving and also collecting endothelial cells. The results obtained in the present research demonstrated that this new protocol allows us to obtain a pure population of VW-MSCs and endothelial cells. VW-MSCs from Göttingen Minipigs responded fully to the MSC minima international criteria, being positive to CD105, CD90, and CD44 and negative to CD45 and CD34. Moreover, VW-MSCs presented a differentiative potential towards osteogenic, chondrogenic, and adipogenic lineages. Overall, the present protocol, preserving the viability and phenotypic features of the two isolated populations, opens future possibilities of using minipig VW-MSCs and endothelial cells in in vitro vascular remodeling studies.

Mesenchymal stem cells modulate IL-17 and IL-9 production induced by Th17-inducing cytokine conditions in autoimmune arthritis: an explorative analysis

BACKGROUND

The importance of proinflammatory T-cells and their cytokine production in patients with autoimmune arthritis has been widely described. Due to their immunomodulatory properties, mesenchymal stem cells (MSCs) have come into focus as a potential therapeutic concept. The aim of this study was to investigate the influence of MSCs on the phenotype, cytokine profile, and functionality of naive and non-naive CD4+ T-cells from healthy donors (HD) and patients with autoimmune arthritis under Th17-cytokine polarizing conditions in an explorative way using a transwell system prohibiting any cell-cell-contact.

METHODS

Magnetically isolated naive and non-naive CD4+ T-cells were stimulated under Th17-polarizing proinflammatory cytokine conditions in presence and absence of bone marrow derived mesenchymal stromal cells (MSCs). After an incubation period of 6 days, the proportions of the T-cell subpopulations TEMRA (CD45RA+CD27-), memory (CD45RA-CD27+), effector (CD45RA-CD27-) and naive cells (CD45RA+CD27+) were determined. Quantitative immunofluorescence intensity was used as a measure for IL-9, IL-17 and IFN-γ production in each subpopulation.

RESULTS

In isolated naive CD4+ T-cells from HD and patients, MSCs suppressed the differentiation of naive towards an effector phenotype while memory and naive cells showed higher percentages in culture with MSCs. In patients, MSCs significantly decreased the proportion of IL-9 and IL-17 producing effector T-cells. MSCs also reduced IFN-γ production in the naive and memory phenotype from HD.

CONCLUSION

The results of the study indicate significant immunomodulatory properties of MSCs, as under Th17-polarizing conditions MSCs are still able to control T-cell differentiation and proinflammatory cytokine production in both HD and patients with autoimmune arthritis.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Extracellular Vesicles to Treat PCOS

Polycystic ovary syndrome (PCOS) is known as the most common endocrine disorder in women. Previously, we suggested that human mesenchymal stem cells (MSCs) can reverse the PCOS condition by secreting factors. Here, we evaluated the therapeutic capability of MSC-derived extracellular vesicles (EVs), also known as exosomes, in both in vitro and in vivo PCOS models. Exosomes were used to treat androgen-producing H293R cells and injected in a mouse model through intraovarian and intravenous injection into a letrozole (LTZ)-induced PCOS mouse model. We assessed the effects of the exosomes on androgen-producing cells or the PCOS mouse model by analyzing steroidogenic gene expression (quantitative real-time polymerase chain reaction (qRT-PCR)), body weight change, serum hormone levels, and fertility by pup delivery. Our data show the therapeutic effect of MSC-derived EVs for reversing PCOS conditions, including fertility issues. Interestingly, intravenous injection was more effective for serum glucose regulation, and an intraovarian injection was more effective for ovary restoration. Our study suggests that MSC-derived exosomes can be promising biopharmaceutics for treating PCOS conditions as a novel therapeutic option. Despite the fact that we need more validation in human patients, we may evaluate this novel treatment option for PCOS with the following clinical trials.

Preconditioned Chorionic Villus Mesenchymal Stem/Stromal Cells (CVMSCs) Minimize the Invasive Phenotypes of Breast Cancer Cell Line MDA231 In Vitro

Among the newer choices of targeted therapies against cancer, stem cell therapy is gaining importance because of their antitumor properties. Stem cells suppress growth, metastasis, and angiogenesis, and induce apoptosis in cancer cells. In this study, we have examined the impact of the cellular component and the secretome of preconditioned and naïve placenta-derived Chorionic Villus Mesenchymal Stem Cells (CVMSCs) on the functional characteristics of the Human Breast Cancer cell line MDA231. MDA231 cells were treated with preconditioned CVMSCs and their conditioned media (CM), followed by an evaluation of their functional activities and modulation in gene and protein expression. Human Mammary Epithelial Cells (HMECs) were used as a control. CM obtained from the preconditioned CVMSCs significantly altered the proliferation of MDA231 cells, yet no change in other phenotypes, such as adhesion, migration, and invasion, were observed at various concentrations and time points tested. However, the cellular component of preconditioned CVMSCs significantly inhibited several phenotypes of MDA231 cells, including proliferation, migration, and invasion. CVMSCs-treated MDA231 cells exhibited modulation in the expression of various genes involved in apoptosis, oncogenesis, and Epithelial to Mesenchymal Transition (EMT), explaining the changes in the invasive behavior of MDA231 cells. These studies reveal that preconditioned CVMSCs may make useful candidate in a stem cell-based therapy against cancer.

Human Adipose-Derived Stem Cells Reduce Cellular Damage after Experimental Spinal Cord Injury in Rats

Traumatic spinal cord injury (SCI) is a devastating condition without an effective therapy. Cellular therapies are among the promising treatment strategies. Adult stem cells, such as mesenchymal stem cells, are often used clinical research for their immunomodulatory and regenerative potential. This study aimed to evaluate the effect of human adipose tissue-derived stem cells (ADSC) infusion through the cauda equina in rats with SCI. The human ADSC from bariatric surgery was isolated, expanded, and characterized. Wistar rats were subjected to blunt SCI and were divided into four groups. Two experimental groups (EG): EG1 received one ADSC infusion after SCI, and EG2 received two infusions, the first one after SCI and the second infusion seven days after the injury. Control groups (CG1 and CG2) received infusion with a culture medium. In vivo, cell tracking was performed 48 h and seven days after ADSC infusion. The animals were followed up for 40 days after SCI, and immunohistochemical quantification of myelin, neurons, and astrocytes was performed. Cellular tracking showed cell migration towards the injury site. ADSC infusion significantly reduced neuronal loss, although it did not prevent the myelin loss or enhance the area occupied by astrocytes compared to the control group. The results were similar when comparing one or two cell infusions. The injection of ADSC distal to the injured area was shown to be a safe and effective method for cellular administration in spinal cord injury.

Autologous bone marrow-derived nucleated cell (aBMNC) transplantation improves endometrial function in patients with refractory Asherman's syndrome or with thin and dysfunctional endometrium

PURPOSE

The purpose was to evaluate the effect of intrauterine injection of aBMNC on the endometrial function in patients with refractory Asherman's syndrome (AS) and/or thin and dysfunctional endometrium (TE).

STUDY DESIGN

This is a prospective, experimental, non-controlled study MATERIAL AND METHODS: The study was carried out between December 2018 and December 2020 on 20 patients, who were of age < 45 years and had oligo/amenorrhea and primary infertility due to refractory AS and/or TE. One hundred ml BM was extracted. aBMNC cells were separated according to generic volume reduction protocol by using the Cell Separation System SEPAX S-100 table top centrifuge system. We have evaluated CD34+, mononuclear cell (MNC), and total nucleated cell (TNC) counts. The transplantation aBMNC was performed by two intrauterine injections at an interval of one week, transvaginally into the endometrial-myometrial junction by an ovum aspiration needle. Midcyclic endometrial thickness (ET) and gestations after transplantation were evaluated.

RESULTS

The mean TNC, MNC, and CD34+ cells were 11.55 ± 4.7 × 108, 3.85 ± 2.01 × 108, and 7.00 ± 2.88 × 106 at first injection, respectively, and 6.85 ± 2.67 × 108, 2.04 ± 1.11 × 108, and 3.44 ± 1.31 × 106 at second injection, respectively. The maximum posttransplantation ET was significantly higher than the maximum pretransplantation ET: 2.97 ± 0.48 vs. 5.76 ± 1.19 (mean ± standard deviation, p < 0.01). Twelve patients had frozen-thaw embryo transfers after the study. In 42% (n = 5 of 12) of the patients, pregnancy was achieved. One of the five patients delivered a healthy baby at term.

CONCLUSIONS

Autologous BMNC transplantation may contribute to endometrial function in patients with AS and/or TE.

Mesenchymal Stem Cell-derived Exosomes: Novel Therapeutic Approach for Inflammatory Bowel Diseases

As double membrane-encapsulated nanovesicles (30-150 nm), exosomes (Exos) shuttle between different cells to mediate intercellular communication and transport active cargoes of paracrine factors. The anti-inflammatory and immunomodulatory activities of mesenchymal stem cell (MSC)-derived Exos (MSC-Exos) provide a rationale for novel cell-free therapies for inflammatory bowel disease (IBD). Growing evidence has shown that MSC-Exos can be a potential candidate for treating IBD. In the present review, we summarized the most critical advances in the properties of MSC-Exos, provided the research progress of MSC-Exos in treating IBD, and discussed the molecular mechanisms underlying these effects. Collectively, MSC-Exos had great potential for cell-free therapy in IBD. However, further studies are required to understand the full dimensions of the complex Exo system and how to optimize its effects.

Is mandible derived mesenchymal stromal cells superior in proliferation and regeneration to long bone-derived mesenchymal stromal cells?

Mesenchymal stromal cells (MSCs) are cells with the characteristic ability of self-renewal along with the ability to exhibit multilineage differentiation. Bone marrow (BM) is the first tissue in which MSCs were identified and BM-MSCs are most commonly used among various MSCs in clinical settings. MSCs can stimulate and promote osseous regeneration. Due to the difference in the development of long bones and craniofacial bones, the mandibular-derived MSCs (M-MSCs) have distinct differentiation characteristics as compared to that of long bones. Both mandibular and long bone-derived MSCs are positive for MSC-associated markers such as CD-73, -105, and -106, stage-specific embryonic antigen 4 and Octamer-4, and negative for hematopoietic markers such as CD-14, -34, and -45. As the M-MSCs are derived from neural crest cells, they have embryogenic cells which promote bone repair and high osteogenic potential. In vitro and in vivo animal-based studies demonstrate a higher rate of proliferation and high osteogenic potential for M-MSCs as compared to long-bones MSCs, but in vivo studies in human subjects are lacking. The BM-MSCs have their advantages and limitations. M-MSCs may be utilized as an alternative source of MSCs which can be utilized for tissue engineering and promoting the regeneration of bone. M-MSCs may have potential advantages in the repair of craniofacial or orofacial defects. Considering the utility of M-MSCs in the field of orthopaedics, we have discussed various unresolved questions, which need to be explored for their better utility in clinical practice.

Relationship between hematoma-like tissue on the footprint and structural outcome of arthroscopic rotator cuff repair with a transosseous technique

Background

We have tried to create hematoma over the footprint site at the end of arthroscopic rotator cuff repair (ARCR) surgery, expecting to apply biochemical effects of the platelet-related factors. The purpose of this study was to investigate the presence of hematoma-like tissue (HLT) on postoperative magnetic resonance imaging, and to evaluate the relationship between the HLT and the structural outcomes of ARCR.

Materials and methods

Twenty-five patients were reviewed with a mean age at surgery of 69.8 years (range, 52-85 years). Postoperative magnetic resonance imaging was performed at 1 week, 6-8 weeks, and >6 months postoperatively. Structural outcomes for the repaired cuff and thickness of HLT were evaluated on coronal T2-weighted images. Signal intensity of HLT was evaluated on coronal T2-weighted fat-suppressed images as the ratio compared to supraspinatus tendon intensity (HLT/SSP ratio).

Results

Structural outcomes showed Sugaya type 1 in 12 shoulders, type 2 in 4, and type 3 in 9. HLT thickness was significantly thicker at 1 week and 6-8 weeks postoperatively in Sugaya type 1 patients than in type 3 patients (1 week; P = .014, 6-8 weeks; P < .001). HLT/SSP ratio gradually decreased (at 1 week; 1.9 ± 0.7, 6-8 weeks; 1.6 ± 0.6, >6 months; 1.2 ± 0.5), and differed significantly between >6 months and both 1 week and 6-8 weeks (P < .001 each).

Mechanistic approach of the therapeutic potential of mesenchymal stem cells on brain damage in irradiated mice: emphasis on anti-inflammatory and anti-apoptotic effects

BACKGROUND AND OBJECTIVES

Brain damage which has been induced by radiation generally occurs in radiotherapeutics patients. Stem cell transplantation represents a vital applicant for alleviating neurodegenerative disorders. This work aims at exploring the potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) on brain injury induced by γ radiation in mice and the possible underlying mechanisms were elucidated.

MATERIALS AND METHODS

Mice were allocated into three groups; Group I (Control), Group II (Irradiated control) where mice submitted to 5 Gy of whole-body γ radiation, Group III (Irradiated + BM-MSCs) where mice were intravenously injected of BM-MSCs at a dose of 106 cells/mice 24 h following irradiation. Animals were sacrificed 28 d following exposure to γ radiation.

RESULTS

It was observed that BM-MSCs therapy provided a valuable tissue repair as evidenced by a reduction in inflammatory mediators including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), nuclear factor kappa (NF-κβ), phosphorylated NF-κβ-p65 (P-NF-κβ-p65), interferon-gamma (IFNγ) and monocyte chemoattractant protein-1 (MCP-1) associated with decreased levels of transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF) in brain tissues of irradiated mice. Furthermore, neuronal apoptosis was declined in brain tissues of the BM-MSCs group as remarkable inhibition of caspase-3 and Bax accompanied by elevation of Bcl-2 proteins expression. These results were supported by histopathological investigation.

CONCLUSIONS

In conclusion, BM-MSCs could display a vital rule in alleviating brain injury in radio-therapeutic patients.

Clinical Trials Targeting Secondary Damage after Traumatic Spinal Cord Injury

Spinal cord injury (SCI) often causes loss of sensory and motor function resulting in a significant reduction in quality of life for patients. Currently, no therapies are available that can repair spinal cord tissue. After the primary SCI, an acute inflammatory response induces further tissue damage in a process known as secondary injury. Targeting secondary injury to prevent additional tissue damage during the acute and subacute phases of SCI represents a promising strategy to improve patient outcomes. Here, we review clinical trials of neuroprotective therapeutics expected to mitigate secondary injury, focusing primarily on those in the last decade. The strategies discussed are broadly categorized as acute-phase procedural/surgical interventions, systemically delivered pharmacological agents, and cell-based therapies. In addition, we summarize the potential for combinatorial therapies and considerations.

Disentangling the aetiological pathways between body mass index and site-specific cancer risk using tissue-partitioned Mendelian randomisation

BACKGROUND

Body mass index (BMI) is known to influence the risk of various site-specific cancers, however, dissecting which subcomponents of this heterogenous risk factor are predominantly responsible for driving disease effects has proven difficult to establish. We have leveraged tissue-specific gene expression to separate the effects of distinct phenotypes underlying BMI on the risk of seven site-specific cancers.

METHODS

SNP-exposure estimates were weighted in a multivariable Mendelian randomisation analysis by their evidence for colocalization with subcutaneous adipose- and brain-tissue-derived gene expression using a recently developed methodology.

RESULTS

Our results provide evidence that brain-tissue-derived BMI variants are predominantly responsible for driving the genetically predicted effect of BMI on lung cancer (OR: 1.17; 95% CI: 1.01-1.36; P = 0.03). Similar findings were identified when analysing cigarettes per day as an outcome (Beta = 0.44; 95% CI: 0.26-0.61; P = 1.62 × 10-6), highlighting a possible shared aetiology or mediator effect between brain-tissue BMI, smoking and lung cancer. Our results additionally suggest that adipose-tissue-derived BMI variants may predominantly drive the effect of BMI and increased risk for endometrial cancer (OR: 1.71; 95% CI: 1.07-2.74; P = 0.02), highlighting a putatively important role in the aetiology of endometrial cancer.

CONCLUSIONS

The study provides valuable insight into the divergent underlying pathways between BMI and the risk of site-specific cancers.

Mesenchymal stromal cells derived from exfoliated deciduous teeth express neuronal markers before differentiation induction

OBJECTIVE

This study aimed to evaluate neuronal markers in stromal cells from human exfoliated deciduous teeth (SHED) and standardize the isolation and characterization of those cells.

METHODOLOGY

Healthy primary teeth were collected from children. The cells were isolated by enzymatic digestion with collagenase. By following the International Society for Cell and Gene Therapy (ISCT) guidelines, SHED were characterized by flow cytometry and differentiated into osteogenic, adipogenic, and chondrogenic lineages. Colony-forming unit-fibroblasts (CFU-F) were performed to assess these cells' potential and efficiency. To clarify the neuronal potential of SHED, the expression of nestin and βIII-tubulin were examined by immunofluorescence and SOX1, SOX2, GFAP, and doublecortin (DCX), nestin, CD56, and CD146 by flow cytometry.

RESULTS

SHED showed mesenchymal stromal cells characteristics, such as adhesion to plastic, positive immunophenotypic profile for CD29, CD44, CD73, CD90, CD105, and CD166 markers, reduced expression for CD14, CD19, CD34, CD45, HLA-DR, and differentiation in three lineages confirmed by staining and gene expression for adipogenic differentiation. The average efficiency of colony formation was 16.69%. SHED expressed the neuronal markers nestin and βIII-tubulin; the fluorescent signal intensity was significantly higher in βIII-tubulin (p<0.0001) compared to nestin. Moreover, SHED expressed DCX, GFAP, nestin, SOX1, SOX2, CD56, CD146, and CD271. Therefore, SHED had a potential for neuronal lineage even without induction with culture medium and specific factors.

CONCLUSION

SHEDs may be a new therapeutic strategy for regenerating and repairing neuronal cells and tissues.

An investigation of a self-assembled cell-extracellular complex and its potentials in improving wound healing

BACKGROUND

To maintain and enhance the wound healing effects of mesenchymal stem cells (MSCs), a scaffold for hosting MSCs is needed, which ought to be completely biocompatible, durable, producible, and of human source.

OBJECTIVE

To build a cell-extracellular matrix (ECM) complex assembled by human umbilical cord mesenchymal stem cells (HuMSCs) and to investigate its clinical potentials in promoting wound healing.

METHOD

HuMSCs were isolated and expanded. When the cells of third passage reached confluency, ascorbic acid was added to stimulate the cells to deposit ECM where the cells grew in. Four weeks later, a cells-loaded ECM sheet was formed. The cell-ECM complex was observed under the scanning electron microscopy (SEM) and subjected to histological studies. The supernatants were collected and the cell-ECM complex was harvested at different time points and processed for enzyme-linked immune sorbent assay (ELISA) and mRNA analysis. The in vivo experiments were performed by means of implanting the cell-ECM complex on the mice back for up to 6 months and the specimens were collected for histological studies.

RESULTS

After 4 weeks of cultivation with ascorbic stimulation, a sheet was formed which is mainly composed with HuMSCs, collagen and hyaluronic acid. The cell-ECM complex can sustain to certain tensile force. The mRNA and protein levels of vascular endothelial growth factor-α (VEGF-α), hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), and transforming growth factor-β1 (TGF-β1) were remarkably increased compared to monolayer-cultured cells. The implanted cell-ECM complex on mice was still noticeable with host cells infiltration and vascularization on 6 months.

CONCLUSION

Our studies suggested that HuMSCs can be multi-cultivated through adding ascorbic stimulation and ECM containing collagen and hyaluronic acid were enriched around the cells which self-assembly formed a cell-ECM complex. Cell-ECM complex can improve growth factors secretion remarkably which means it may promote wound healing by paracrine.

Mesenchymal stem cells for regenerative medicine in central nervous system

Mesenchymal stem cells (MSCs) are multipotent stem cells, whose paracrine and immunomodulatory potential has made them a promising candidate for central nervous system (CNS) regeneration. Numerous studies have demonstrated that MSCs can promote immunomodulation, anti-apoptosis, and axon re-extension, which restore functional neural circuits. The therapeutic effects of MSCs have consequently been evaluated for application in various CNS diseases including spinal cord injury, cerebral ischemia, and neurodegenerative disease. In this review, we will focus on the research works published in the field of mechanisms and therapeutic effects of MSCs in CNS regeneration.

Osteogenic Differentiation of Canine Adipose Derived Mesenchymal Stem Cells on B-TCP and B-TCP/Collagen Biomaterials

Mesenchymal stem cells are adult stem cells that have the ability to differentiate into osteogenic, chondrogenic, adipogenic and myogenic lineages. In the field of orthopedics and traumatology, mesenchymal stem cells in combination with biomaterials are used especially for the treatment of bone fractures and diseases in both humans and animals. The purpose of this study is to promote growth, proliferation and osteogenic differentiation of mesenchymal stem cells that were isolated from the adipose tissue of canines on B-TCP (Beta-tricalcium phosphate) and B-TCP/Collagen biomaterials. MTT analysis was performed to test the cell adhesion and proliferation on B-TCP and B-TCP/Collagen biomaterials that were used to mimic the extracellular matrix of three-dimensional bone tissue. Scanning electron microscope analysis was performed to show general surface characters of B-TCP and B-TCP /Collagen biomaterials. The osteoinductive capacities of the B-TCP and B-TCP/Collagen biomaterials were determined by alkaline phosphatase and Von Kossa stainings, and RT-PCR analysis. The ALP activity of the B-TCP/Col containing material was significantly higher than the B-TCP on the first days. In terms of gene expression, there were no significant differences except 14th-day SPARC gene expression. The results of Von Kossa staining indicate that B-TCP/Col has above the desired level degradation capacity. As a result of this research, although it is advantageous in terms of alkaline phosphatase activity and osteogenic gene expression compared to B-TCP material, it is thought that B-TCP/Collagen biomaterial should be developed for use in bone tissue engineering due to its high degradation property.

Subacute traumatic spinal cord injury: a systematic review and network meta-analysis of therapeutic strategies based on bone marrow mesenchymal stromal cells in animal models

BACKGROUND AIMS

To explore the optimal transplantation strategy of bone marrow mesenchymal stem cells in subacute traumatic spinal cord injury in animal experiments in order to provide reference for future animal studies and clinical research.

METHODS

The PubMed, Embase and Web of Science databases were systematically searched (inception to January 4, 2022). Literature search, data extraction and bias assessment were performed by two independent reviewers.

RESULTS

A total of 50 articles were included for analysis. Results of both traditional meta-analysis and network meta-analysis showed that high-dose (≥1 × 10⁶) transplantation was significantly better than low-dose (<1 × 10⁶) transplantation and intralesional transplantation was significantly better than intravenous transplantation.

CONCLUSIONS

Given the limited quality of evidence from current animal studies, more high-quality head-to-head comparisons are needed in the future to delve into the optimal transplantation strategy for stem cells.

Within or Without You? A Perspective Comparing In Situ and Ex Situ Tissue Engineering Strategies for Articular Cartilage Repair

Human articular cartilage has a poor ability to self-repair, meaning small injuries often lead to osteoarthritis, a painful and debilitating condition which is a major contributor to the global burden of disease. Existing clinical strategies generally do not regenerate hyaline type cartilage, motivating research toward tissue engineering solutions. Prospective cartilage tissue engineering therapies can be placed into two broad categories: i) Ex situ strategies, where cartilage tissue constructs are engineered in the lab prior to implantation and ii) in situ strategies, where cells and/or a bioscaffold are delivered to the defect site to stimulate chondral repair directly. While commonalities exist between these two approaches, the core point of distinction-whether chondrogenesis primarily occurs "within" or "without" (outside) the body-can dictate many aspects of the treatment. This difference influences decisions around cell selection, the biomaterials formulation and the surgical implantation procedure, the processes of tissue integration and maturation, as well as, the prospects for regulatory clearance and clinical translation. Here, ex situ and in situ cartilage engineering strategies are compared: Highlighting their respective challenges, opportunities, and prospects on their translational pathways toward long term human cartilage repair.

Alleviation of Severe Skin Insults Following High-Dose Irradiation with Isolated Human Fetal Placental Stromal Cells

Skin exposure to high-dose irradiation, as commonly practiced in radiotherapy, affects the different skin layers, causing dry and wet desquamation, hyperkeratosis fibrosis, hard to heal wounds and alopecia and damaged hair follicles. Fetal tissue mesenchymal stromal cells (f-hPSC) were isolated from excised human fetal placental tissue, based on their direct migration from the tissue samples to the tissue dish. The current study follows earlier reports on for the mitigation of acute radiation syndrome following whole body high-dose exposure with remotely injected f-hPSC. Both the head only and a back skin flap of mice were irradiated with 16 &18 Gy, respectively, by 6MeV clinical linear accelerator electron beam. In both locations, the irradiated skin areas developed early and late radiation induced skin damages, including cutaneous fibrosis, lesions, scaring and severe hair follicle loss and reduced hair pigmentation. Injection of 2 × 106 f-hPSC, 3 and 8 weeks following 16 Gy head irradiation, and 1 and 4 weeks following the 18 Gy back skin only irradiation, resulted in significantly faster healing of radiation induced damages, with reduction of wet desquamation as measured by surface moisture level and minor recovery of the skin viscoelasticity. Detailed histological morphometry showed a clear alleviation of radiation induced hyperkeratosis in f-hPSC treated mice, with significant regain of hair follicles density. Following 16 Gy head irradiation, the hair follicles density in the scalp skin was reduced significantly by almost a half relative to the controls. A nearly full recovery of hair density was found in the f-hPSC treated mice. In the 18 Gy irradiated back skin, the hair follicles density dropped in a late stage by ~70% relative to naïve controls. In irradiated f-hPSC treated mice, it was reduced by only ~30% and was significantly higher than the non-treated group. Our results suggest that local injections of xenogeneic f-hPSC could serve as a simple, safe and highly effective non-autologous pro-regenerative treatment for high-dose radiation induced skin insults. We expect that such treatment could also be applied for other irradiated organs.

Histoarchitecture of the fibrillary matrix of human fetal posterior tibial tendons

Adult tendons are highly differentiated. In mature individuals, tendon healing after an injury occurs through fibrotic tissue formation. Understanding the intrinsic reparative properties of fetal tendons would help to understand the maturation tissue process and tendon tissue repair. The present study evaluated the evolution of histoarchitecture, cellularity and the distribution of collagens I, III and V in the posterior tibial tendon in human fetuses at different gestational ages. Morphological profiles were assessed in nine fresh spontaneously aborted fetuses (Group I: five fetuses aged between 22 and 28 weeks of gestation; Group II: four fetuses aged between 32 and 38 weeks of gestation), characterized by a combination of histology, fluorescence and immunohistochemistry. In Group I, the posterior tibial tendon showed statistically significant greater cellularity and presence of collagen III and V than in Group II tendon, which showed a predominance of collagenous I and a better organization of the extracellular matrix compared with Group I tendons. In addition, a statistically significant higher rate of CD90, a marker of mesenchymal cells, was found in Group I tendons. In fetuses with gestational age between 22 and 28 weeks, the posterior tibialis tendons showed a thin and disorganized fibrillar structure, with an increase in collagen III and V fibers and mesenchymal cells. In the posterior tibialis tendons of fetuses with gestational age between 32 and 38 weeks, the fibrillar structure was thicker with a statistically significant increase in type I collagen and decreased cellularity.

Mesenchymal stem cells to treat female infertility; future perspective and challenges: A review

Infertility negatively impacts the overall health and social life of affected individuals and couples. Female infertility is their inability to perceive pregnancy. To date, polycystic ovary syndrome, primary ovarian insufficiency, fallopian tube obstruction, endometriosis, and intrauterine synechiae have been identified as the primary causes of infertility in women. However, despite the mutual efforts of clinicians and research scientists, the development of an effective treatment modality has met little success in combating female infertility. Intriguingly, significant research has demonstrated mesenchymal stem cells as an optimal source for treating infertility disorders. Therefore, here we attempted to capsulize to date available studies to summarize the therapeutic potential of mesenchymal stem cells in combating infertility in women by focusing on the underlying mechanism through which stem cells can reduce the effects of ovarian disorders. Furthermore, we also discussed the preclinical and clinical application of stem cell therapy, their limitation, and the future perspective to minimize these limitations.

Localized Perivascular Therapeutic Approaches to Inhibit Venous Neointimal Hyperplasia in Arteriovenous Fistula Access for Hemodialysis Use

An arteriovenous fistula (AVF) is the preferred vascular access for chronic hemodialysis, but high failure rates restrict its use. Optimizing patients' perioperative status and the surgical technique, among other methods for preventing primary AVF failure, continue to fall short in lowering failure rates in clinical practice. One of the predominant causes of AVF failure is neointimal hyperplasia (NIH), a process that results from the synergistic effects of inflammation, hypoxia, and hemodynamic shear stress on vascular tissue. Although several systemic therapies have aimed at suppressing NIH, none has shown a clear benefit towards this goal. Localized therapeutic approaches may improve rates of AVF maturation by providing direct structural and functional support to the maturating fistula, as well as by delivering higher doses of pharmacologic agents while avoiding the adverse effects associated with systemic administration of therapeutic agents. Novel materials-such as polymeric scaffolds and nanoparticles-have enabled the development of different perivascular therapies, such as supportive mechanical devices, targeted drug delivery, and cell-based therapeutics. In this review, we summarize various perivascular therapeutic approaches, available data on their effectiveness, and the outlook for localized therapies targeting NIH in the setting of AVF for hemodialysis use. Highlights: Most systemic therapies do not improve AVF patency outcomes; therefore, localized therapeutic approaches may be beneficial. Locally delivered drugs and medical devices may improve AVF patency outcomes by providing biological and mechanical support. Cell-based therapies have shown promise in suppressing NIH by delivering a more extensive array of bioactive substances in response to the biochemical changes in the AVF microenvironment.

Comparison of freshly cultured versus cryopreserved mesenchymal stem cells in animal models of inflammation: A pre-clinical systematic review

Background:

Mesenchymal stem cells (MSCs) are multipotent cells that demonstrate therapeutic potential for the treatment of acute and chronic inflammatory-mediated conditions. Although controversial, some studies suggest that MSCs may lose their functionality with cryopreservation which could render them non-efficacious. Hence, we conducted a systematic review of comparative pre-clinical models of inflammation to determine if there are differences in in vivo measures of pre-clinical efficacy (primary outcomes) and in vitro potency (secondary outcomes) between freshly cultured and cryopreserved MSCs.

Methods:

A systematic search on OvidMEDLINE, EMBASE, BIOSIS, and Web of Science (until January 13, 2022) was conducted. The primary outcome included measures of in vivo pre-clinical efficacy; secondary outcomes included measures of in vitro MSC potency. Risk of bias was assessed by the SYRCLE ‘Risk of Bias’ assessment tool for pre-clinical studies.

Results:

Eighteen studies were included. A total of 257 in vivo pre-clinical efficacy experiments represented 101 distinct outcome measures. Of these outcomes, 2.3% (6/257) were significantly different at the 0.05 level or less; 2 favoured freshly cultured and 4 favoured cryopreserved MSCs. A total of 68 in vitro experiments represented 32 different potency measures; 13% (9/68) of the experiments were significantly different at the 0.05 level or less, with seven experiments favouring freshly cultured MSC and two favouring cryopreserved MSCs.

Conclusions:

The majority of preclinical primary in vivo efficacy and secondary in vitro potency outcomes were not significantly different (p<0.05) between freshly cultured and cryopreserved MSCs. Our systematic summary of the current evidence base may provide MSC basic and clinical research scientists additional rationale for considering a cryopreserved MSC product in their pre-clinical studies and clinical trials as well as help identify research gaps and guide future related research.

Funding:

Ontario Institute for Regenerative Medicine

Fibrocartilaginous Tissue: Why Does It Fail to Heal?

Tendons and ligaments are critical components in the function of the musculoskeletal system, as they provide stability and guide motion for the biomechanical transmission of forces into bone. Several common injuries in the foot and ankle require the repair of ruptured or attenuated tendon or ligament to its osseous insertion. Understanding the structure and function of injured ligaments and tendons is complicated by the variability and unpredictable nature of their healing. The healing process at the tendon/ligament to bone interface is challenging and often frustrating to foot and ankle surgeons, as they have a high failure rate necessitating the need for revision.

Preconditioning Methods to Improve Mesenchymal Stromal Cell-Derived Extracellular Vesicles in Bone Regeneration—A Systematic Review

Simple Summary

The evidence of the therapeutic effects of mesenchymal stromal cells (MSCs), so-called stem cells, in several diseases relies mostly on the substances they secrete, including their extracellular vesicles (EVs). EVs are an important component of cell communication and they carry a cargo that is similar to their parent cell. Cells respond differently based on their microenvironment, and so it is expected that the therapeutic potential of these vesicles can be modulated by the enrichment of their parent cell microenvironment. With this in mind, we conducted a systematic search for papers that preconditioned MSCs and collected their EVs to assess their potential to favor bone formation. The results showed different methods for MSC preconditioning, including chemical induction, culture conditions, and genetic modifications. All methods were able to improve the therapeutic effects of the derived EVs for bone formation. However, the heterogeneity among studies—regarding the type of cell, EV concentration, and scaffolds—made it difficult to compare fairly the types of preconditioning methods. In summary, the microenvironment greatly influences MSCs, and using preconditioning methods can potentially improve the therapeutic effects of their derived EVs in bone regeneration and other bone diseases.

Abstract

Mesenchymal stromal cells (MSCs) have long been used in research for bone regeneration, with evidence of their beneficial properties. In the segmental area of MSC-based therapies, MSC-derived extracellular vesicles (EVs) have also shown great therapeutic effects in several diseases, including bone healing. This study aimed to assess whether the conditioning of MSCs improves the therapeutic effects of their derived extracellular vesicles for bone regeneration. Electronic research was performed until February 2021 to recover the studies in the following databases: PubMed, Scopus, and Web of Science. The studies were screened based on the inclusion criteria. Relevant information was extracted, including in vitro and in vivo experiments, and the animal studies were evaluated for risk of bias by the SYRCLE tool. A total of 463 studies were retrieved, and 18 studies met the inclusion criteria (10 studies for their in vitro analysis, and 8 studies for their in vitro and in vivo analysis). The conditioning methods reported included: osteogenic medium; dimethyloxalylglycine; dexamethasone; strontium-substituted calcium silicate; hypoxia; 3D mechanical microenvironment; and the overexpression of miR-375, bone morphogenetic protein-2, and mutant hypoxia-inducible factor-1α. The conditioning methods of MSCs in the reported studies generate exosomes able to significantly promote bone regeneration. However, heterogeneity regarding cell source, conditioning method, EV isolation and concentration, and defect model was observed among the studies. The different conditioning methods reported in this review do improve the therapeutic effects of MSC-derived EVs for bone regeneration, but they still need to be addressed in larger animal models for further clinical application.

Mesenchymal stem cell homing to improve therapeutic efficacy in liver disease

Mesenchymal stem cell (MSC) transplantation, as an alternative strategy to orthotopic liver transplantation, has been evaluated for treating end-stage liver disease. Although the therapeutic mechanism of MSC transplantation remains unclear, accumulating evidence has demonstrated that MSCs can regenerate tissues and self-renew to repair the liver through differentiation into hepatocyte-like cells, immune regulation, and anti-fibrotic mechanisms. Multiple clinical trials have confirmed that MSC transplantation restores liver function and alleviates liver damage. A sufficient number of MSCs must be home to the target tissues after administration for successful application. However, inefficient homing of MSCs after systemic administration is a major limitation in MSC therapy. Here, we review the mechanisms and clinical application status of MSCs in the treatment of liver disease and comprehensively summarize the molecular mechanisms of MSC homing, and various strategies for promoting MSC homing to improve the treatment of liver disease.

Agathisflavone as a Single Therapy or in Association With Mesenchymal Stem Cells Improves Tissue Repair in a Spinal Cord Injury Model in Rats

Agathisflavone is a flavonoid with anti-neuroinflammatory and myelinogenic properties, being also capable to induce neurogenesis. This study evaluated the therapeutic effects of agathisflavone—both as a pharmacological therapy administered in vivo and as an in vitro pre-treatment aiming to enhance rat mesenchymal stem cells (r)MSCs properties–in a rat model of acute spinal cord injury (SCI). Adult male Wistar rats (n = 6/group) underwent acute SCI with an F-2 Fogarty catheter and after 4 h were treated daily with agathisflavone (10 mg/kg ip, for 7 days), or administered with a single i.v. dose of 1 × 10⁶ rMSCs either unstimulated cells (control) or pretreated with agathisflavone (1 µM, every 2 days, for 21 days in vitro). Control rats (n = 6/group) were treated with a single dose methylprednisolone (MP, 60 mg/kg ip). BBB scale was used to evaluate the motor functions of the animals; after 7 days of treatment, the SCI area was analyzed after H&E staining, and RT-qPCR was performed to analyze the expression of neurotrophins and arginase. Treatment with agathisflavone alone or with of 21-day agathisflavone–treated rMSCs was able to protect the injured spinal cord tissue, being associated with increased expression of NGF, GDNF and arginase, and reduced macrophage infiltrate. In addition, treatment of animals with agathisflavone alone was able to protect injured spinal cord tissue and to increase expression of neurotrophins, modulating the inflammatory response. These results support a pro-regenerative effect of agathisflavone that holds developmental potential for clinical applications in the future.

Platelet-Rich Plasma and Adipose-Derived Mesenchymal Stem Cells in Association with Arthroscopic Microfracture of Knee Articular Cartilage Defects: A Pilot Randomized Controlled Trial

Background

This study aims to compare the effects of platelet-rich plasma (PRP) alone or in combination with adipose-derived mesenchymal stem cells (AD-MSCs) in patients affected by cartilage defects, undergoing knee arthroscopic microfracture.

Methods

Thirty-eight patients diagnosed with a knee monocompartmental cartilage defect (Outerbridge grade IV) on the MRI, underwent an arthroscopic procedure. After the confirmation of the lesion, they all received the same bone marrow stimulation technique (microfracture) and were randomized into two groups: the first one had additional PRP injection (group A), while the second received PRP and AD-MSC injection (group B). Knee assessment and pain score were documented with Knee Injury Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score, Short-Form (SF) 12, and Visual Analogue Scale (VAS) before the treatment and at 1, 3, 6, and 12 months of follow-up postoperatively. An additional arthroscopic procedure, performed in four patients for a subsequent meniscal lesion, let us evaluate cartilage evolution by performing a macro/microscopical assessment on cartilage biopsy specimens.

Results

At the 12-month follow-up, both groups showed a comparable functional improvement. The scores on the IKDC form, KOOS, pain VAS, and SF-12 significantly improved from baseline (p < 0.05) to 12 months postoperatively in both treatment groups. The four second-look arthroscopies showed a complete repair of the articular defects by smooth solid cartilage layer, with a good chondrocytic population, in both groups. A thick smooth hyaline-like cartilage with a predominantly viable cell population and normal mineralization (a form closely resembling native tissue) was observed in group B.

Conclusions

Modern regenerative medicine techniques, such as PRP and AD-MSC, associated with traditional arthroscopic bone marrow stimulating techniques, seem to enhance cartilage restoration ability. The preliminary results of this pilot study encourage the synergic use of these regenerative modulating systems to improve the quality of the regenerated cartilage.

Embedding MSCs in Si-HPMC hydrogel decreased MSC-directed host immune response and increased the regenerative potential of macrophages

Embedding mesenchymal stromal cells (MSCs) in biomaterial is a subject of increasing interest in the field of Regenerative Medicine. Speeding up the clinical use of MSCs is dependent on the use of non-syngeneic models in accordance with Good Manufacturing Practices (GMP) requirements and on costs. To this end, in this study, we analyzed the in vivo host immune response following local injection of silanized hydroxypropyl methylcellulose (Si-HPMC)-embedded human MSCs in a rat model developing colorectal damage induced by ionizing radiation. Plasma and lymphocytes from mesenteric lymph nodes were harvested in addition to colonic tissue. We set up tests, using flow cytometry and a live imaging system, to highlight the response to specific antibodies and measure the cytotoxicity of lymphocytes against injected MSCs. We demonstrated that Si-HPMC protects MSCs from specific antibodies production and from apoptosis by lymphocytes. We also observed that Si-HPMC does not modify innate immune response infiltrate in vivo, and that in vitro co-culture of Si-HPMC-embedded MSCs impacts macrophage inflammatory response depending on the microenvironment but, more importantly, increases the macrophage regenerative response through Wnt-family and VEGF gene expression. This study furthers our understanding of the mechanisms involved, with a view to improving the therapeutic benefits of biomaterial-assisted cell therapy by modulating the host immune response. The decrease in specific immune response against injected MSCs protected by Si-HPMC also opens up new possibilities for allogeneic clinical use.

E3 ligase HUWE1 promotes PDGF D-mediated osteoblastic differentiation of mesenchymal stem cells by effecting polyubiquitination of β-PDGFR

Mesenchymal stem cells (MSCs) are adult stem cell populations and exhibit great potential in regenerative medicine and oncology. Platelet-derived growth factors (PDGFs) are well known to regulate MSC biology through their chemotactic and mitogenic properties. However, their direct roles in the regulation of MSC lineage commitment are unclear. Here, we show that PDGF D promotes the differentiation of human bone marrow mesenchymal stem cells (hBMSCs) into osteoblasts and inhibits hBMSC differentiation into adipocytes. We demonstrate that PDGF D-induced β-actin expression and polymerization are essential for mediating this differential regulation of osteoblastogenesis and adipogenesis. Interestingly, we found that PDGF D induces massive upward molecular weight shifts of its cognate receptor, PDGF receptor beta (β-PDGFR) in hBMSCs, which was not observed in fibroblasts. Proteomic analysis indicated that the E3 ubiquitin ligase HECT, UBA, and WWE domain–containing protein 1 (HUWE1) associates with the PDGF D-activated β-PDGFR signaling complex in hBMSCs, resulting in β-PDGFR polyubiquitination. In contrast to the well-known role of ubiquitin in protein degradation, we provide evidence that HUWE1-mediated β-PDGFR polyubiquitination delays β-PDGFR internalization and degradation, thereby prolonging AKT signaling. Finally, we demonstrate that HUWE1-regulated β-PDGFR signaling is essential for osteoblastic differentiation of hBMSCs, while being dispensable for PDGF D-induced hBMSC migration and proliferation as well as PDGF D-mediated inhibition of hBMSC differentiation into adipocytes. Taken together, our findings provide novel insights into the molecular mechanism by which PDGF D regulates the commitment of hBMSCs into the osteoblastic lineage.

Non-Cytokine Protein Profile of the Mesenchymal Stem Cell Secretome That Regulates the Androgen Production Pathway

Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder in reproductive-aged women, and it typically involves elevated androgen levels. Recently, it has been reported that human bone marrow mesenchymal stem cells (hBM-MSCs) can regulate androgen synthesis pathways. However, the details of the mechanism are still unclear. hBM-MSC-derived secreted factors (the secretome) are promising sources of cell-based therapy as they consist of various types of proteins. It is thus important to know which proteins interact with disease-implicated biomolecules. This work aimed to investigate which secretome components contain the key factor that inhibits testosterone synthesis. In this study, we fractionated hBM-MSC-conditioned media into three fractions based on their molecular weights and found that, of the three fractions, one had the ability to inhibit the androgen-producing genes efficiently. We also analyzed the components of this fraction and established a protein profile of the hBM-MSC secretome, which was shown to inhibit androgen synthesis. Our study describes a set of protein components present in the hBM-MSC secretome that can be used therapeutically to treat PCOS by regulating androgen production for the first time.

Therapeutic Mesenchymal Stem/Stromal Cells: Value, Challenges and Optimization

Cellular therapy aims to replace damaged resident cells by restoring cellular and molecular environments suitable for tissue repair and regeneration. Among several candidates, mesenchymal stem/stromal cells (MSCs) represent a critical component of stromal niches known to be involved in tissue homeostasis. In vitro, MSCs appear as fibroblast-like plastic adherent cells regardless of the tissue source. The therapeutic value of MSCs is being explored in several conditions, including immunological, inflammatory and degenerative diseases, as well as cancer. An improved understanding of their origin and function would facilitate their clinical use. The stemness of MSCs is still debated and requires further study. Several terms have been used to designate MSCs, although consensual nomenclature has yet to be determined. The presence of distinct markers may facilitate the identification and isolation of specific subpopulations of MSCs. Regarding their therapeutic properties, the mechanisms underlying their immune and trophic effects imply the secretion of various mediators rather than direct cellular contact. These mediators can be packaged in extracellular vesicles, thus paving the way to exploit therapeutic cell-free products derived from MSCs. Of importance, the function of MSCs and their secretome are significantly sensitive to their environment. Several features, such as culture conditions, delivery method, therapeutic dose and the immunobiology of MSCs, may influence their clinical outcomes. In this review, we will summarize recent findings related to MSC properties. We will also discuss the main preclinical and clinical challenges that may influence the therapeutic value of MSCs and discuss some optimization strategies.

Effect of Controlled Microtopography on Osteogenic Differentiation of Mesenchymal Stem Cells

Various kinds of controlled microtopographies can promote osteogenic differentiation of mesenchymal stem cells (MSCs), such as microgrooves, micropillars, and micropits. However, the optimal shape, size, and mechanism remain unclear. In this review, we summarize the relationship between the parameters of different microtopographies and the behavior of MSCs. Then, we try to reveal the potential mechanism between them. The results showed that the microgrooves with a width of 4–60 μm and ridge width <10 μm, micropillars with parameters less than 10 μm, and square micropits had the full potential to promote osteogenic differentiation of MSCs, while the micromorphology of the same size could induce larger focal adhesions (FAs), well-organized cytoskeleton, and superior cell areas. Therefore, such events are possibly mediated by microtopography-induced mechanotransduction pathways.

The inhibition of Panc1 cancer cells invasion by hAMSCs secretome through suppression of tyrosine phosphorylation of SGK223 (at Y411 site), c-Src (at Y416, Y530 sites), AKT activity, and JAK1/Stat3 signaling

SGK223 is a scaffolding protein involving in the oncogenic tyrosine kinase signaling. SGK223 was phosphorylated at Y411 by c-Src and in response to the Epidermal growth factor receptor (EGFR). Tyrosine phosphorylated SGK223 at Y411 enables to interact with CSK resulting up regulation of c-Src activity and promotion of the cell migration. Human amniotic mesenchymal stromal cells (hAMSCs) are a population of multipotent cells that it was considered to be as a potential platform in cancer therapy. Herein, we employed a co-culture system to clarify the effects of hAMSCs secretome through tyrosine phosphorylation of c-Src, SGK223, AKT activity, and JAK1/Stat3 signaling in Panc1 pancreatic cancer cells. By using the 0.4 μm pore sized transwell membranes, both cell lines were firstly co-cultured for 72 h. Next, c-Src activity (tyrosine phosphorylation levels at Y530 and Y416), tyrosine phosphorylation level of SGK223 (at Y411), AKT activity, and JAK1/Stat3 signaling in Panc1 cells after treatment with hAMSCs were evaluated. Our results showed that hAMSCs have the inhibitory effects on Panc1 pancreatic cancer cells invasion and it suggests that the suppression of c-Src activity, SGK223 expression, AKT activity, and JAK1/Stat3 signaling may be as critical targets in pancreatic cancer therapy.

Mesenchymal Stem Cell-Based Therapy as a New Approach for the Treatment of Systemic Sclerosis

Systemic sclerosis (SSc) is an intractable autoimmune disease with unmet medical needs. Conventional immunosuppressive therapies have modest efficacy and obvious side effects. Targeted therapies with small molecules and antibodies remain under investigation in small pilot studies. The major breakthrough was the development of autologous haematopoietic stem cell transplantation (AHSCT) to treat refractory SSc with rapidly progressive internal organ involvement. However, AHSCT is contraindicated in patients with advanced visceral involvement. Mesenchymal stem cells (MSCs) which are characterized by immunosuppressive, antifibrotic and proangiogenic capabilities may be a promising alternative option for the treatment of SSc. Multiple preclinical and clinical studies on the use of MSCs to treat SSc are underway. However, there are several unresolved limitations and safety concerns of MSC transplantation, such as immune rejections and risks of tumour formation, respectively. Since the major therapeutic potential of MSCs has been ascribed to their paracrine signalling, the use of MSC-derived extracellular vesicles (EVs)/secretomes/exosomes as a "cell-free" therapy might be an alternative option to circumvent the limitations of MSC-based therapies. In the present review, we overview the current knowledge regarding the therapeutic efficacy of MSCs in SSc, focusing on progresses reported in preclinical and clinical studies using MSCs, as well as challenges and future directions of MSC transplantation as a treatment option for patients with SSc.

Synovium Derived Mesenchymal Stromal Cells (Sy-MSCs): A Promising Therapeutic Paradigm in the Management of Knee Osteoarthritis

Synovium-derived mesenchymal stromal cell (Sy-MSC) is a newer member of the mesenchymal stromal cell families. The first successful demonstration of the mesenchymal stromal cell from the human synovial membrane was done in 2001 and since then its potential role for musculoskeletal regeneration has been keenly documented. The regenerative effects of Sy-MSCs are through paracrine signaling, direct cell-cell interactions, and extracellular vehicles. Sy-MSCs possess superior chondrogenicity than other sources of mesenchymal stromal cells. This article aims to outline the advancement of synovium-derived mesenchymal stromal cells along with a specific insight into the application for managing osteoarthritis knee.