Mesenchymal Stromal Cell Therapy Research Articles

Unlocking the full potential of mesenchymal stromal cell therapy for osteoarthritis through machine learning-based in silico trials

Despite the potential of mesenchymal stromal cells (MSCs) in osteoarthritis (OA) treatment, the challenge lies in addressing their therapeutic inconsistency. Clinical trials revealed significantly varied therapeutic outcomes among patients receiving the same allogenic MSCs but different treatment regimens. Therefore, optimizing personalized treatment strategies is crucial to fully unlock MSCs’ potential and enhance therapeutic consistency. We employed the XGBoost algorithm to train a self-collected database comprising 37 published clinical reports to create a model capable of predicting the probability of effective pain relief and WOMAC index improvement in OA patients undergoing MSC therapy. Leveraging this model, extensive in silico simulations were conducted to identify optimal personalized treatment strategies and ideal patient profiles. Our in silico trials predicted that the individually optimized MSC treatment strategies would substantially increase patients' chances of recovery compared to the strategies used in reported clinical trials, thereby potentially benefiting 78.1%, 47.8%, 94.4%, and 36.4% of the patients with ineffective short-term pain relief, short-term WOMAC index improvement, long-term pain relief, and long-term WOMAC index improvement, respectively. We further recommended guidelines on MSC number, concentration, and the patients' appropriate physical (BMI, age, etc.) and disease states (Kellgren-Lawrence grade, etc.) for OA treatment. Additionally, we revealed the superior efficacy of MSC in providing short-term pain relief compared to platelet-rich plasma therapy for most OA patients. This study represents the pioneering effort to enhance the efficacy and consistency of MSC therapy through machine learning applied to clinical data. The in silico trial approach holds immense potential for diverse clinical applications.

Encapsulated Mesenchymal Stromal Cells as Cyclic Providers of Immunomodulatory Secretomes: A Living on-Demand Delivery System.

The stimulation of mesenchymal stromal cells (MSCs) with inflammatory molecules is often used to boost their therapeutic effect. Prolonged exposure to inflammatory molecules has been explored to improve their action because MSCs therapies seem to be improved transiently with such stimuli. However, the possibility of cyclically stimulating MSCs to recover their optimized therapeutic potential is still to be elucidated, although the efficacy of cell-based therapies may be dependent on the ability to readapt to the relapse pathological conditions. Here, the response of MSCs, encapsulated in alginate hydrogels and cultured for 22 d, is explored using three different regimes: single, continuous, and intermittent stimulation with IFNγ. Exposure to IFNγ leads to a decrease in the secretion of IL-10, which is cyclically countered by IFNγ weaning.Conditioned media collected at different stages of pulsatile stimulation show an immunomodulatory potential toward macrophages, which directly correlates with IL-10 concentration in media. To understand whether the correlation between cyclic stimulation of MSCs and other biological actions can be observed, the effect on endothelial cells is studied, showcasing an overall modest influence on tube formation. Overall, the results describe the response of encapsulated MSCs to unusual pulsatile simulation regimens, exploring encapsulated MSCs as a living on-demand release system of tailored secretomes with recoverable immunomodulatory action.

(228) - A Double-Blind, Randomized Controlled Study Evaluating Allogeneic Adipose Tissue Derived Mesenchymal Stromal Cell Therapy to Reduce Primary Graft Dysfunction After Lung Transplantation

(228) - A Double-Blind, Randomized Controlled Study Evaluating Allogeneic Adipose Tissue Derived Mesenchymal Stromal Cell Therapy to Reduce Primary Graft Dysfunction After Lung Transplantation

Mesenchymal stromal cell therapy for COVID-19 acute respiratory distress syndrome: a double-blind randomised controlled trial.

Mesenchymal stromal cells (MSC) have immunomodulatory and tissue-regenerative properties and have shown promising results in acute respiratory distress syndrome (ARDS) of multiple causes, including COVID-19. We conducted a randomised (1:1), placebo-controlled, double-blind clinical trial to assess the efficacy and safety of one bone marrow-derived MSC infusion in twenty patients with moderate to severe ARDS caused by COVID-19. The primary endpoint (increase in PaO2/FiO2 ratio from baseline to day 7, MSC 83.3 versus placebo 57.6) was not statistically significant, although a clinical improvement at day 7 in the WHO scale was observed in MSC patients (5, 50% vs 0, 0%, p = 0.033). Median time to discontinuation of supplemental oxygen was also shorter in the experimental arm (14 versus 23 days, p = 0.007), resulting in a shorter hospital stay (17.5 versus 28 days, p = 0.042). No significant differences were observed for other efficacy or safety secondary endpoints. No infusion or treatment-related serious adverse events occurred during the one-year follow-up. This study did not meet the primary endpoint of PaO2/FiO2 increase by day 7, although itsuggests that MSC are safe in COVID-19 ARDS and may accelerate patients' clinical recovery and hospital discharge. Larger studies are warranted to elucidate their role in ARDS and other inflammatory lung disorders.Trial Registration: EudraCT Number: 2020-002193-27, registered on July 14th, 2020, https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-002193-27/ES . NCT number: NCT04615429, registered on November 4th, 2020, https://clinicaltrials.gov/ct2/show/NCT04615429 .

Efficacy and Safety of Umbilical Cord-Derived Mesenchymal Stromal Cell Therapy in Preclinical Models of Sepsis: A Systematic Review and Meta-analysis.

In preclinical studies, mesenchymal stromal cells (MSCs), including umbilical cord-derived MSCs (UC-MSCs), demonstrate the ability to modulate numerous pathophysiological processes related to sepsis; however, a systematic synthesis of the literature is needed to assess the efficacy of UC-MSCs for treating sepsis. To examine the effects of UC-MSCs on overall mortality (primary outcome) as well as on organ dysfunction, coagulopathy, endothelial permeability, pathogen clearance, and systemic inflammation (secondary outcomes) at prespecified time intervals in preclinical models of sepsis. A systematic search was conducted on Embase, Ovid MEDLINE, and Web of Science up to June 20, 2023. Preclinical controlled studies using in vivo sepsis models with systemic UC-MSC administration were included. Meta-analyses were conducted and expressed as odds ratios (OR) and ratios of the weighted means with 95% CI for categorical and continuous data, respectively. Risk of bias was assessed with the SYRCLE tool. Twenty-six studies (34 experiments, n = 1258 animals) were included in this review. Overall mortality was significantly reduced with UC-MSC treatment as compared to controls (OR: 0.26, 95% CI: 0.18-0.36). At various prespecified time intervals, UC-MSCs reduced surrogate measures of organ dysfunction related to the kidney, liver, and lung; reduced coagulopathy and endothelial permeability; and enhanced pathogen clearance from multiple sites. UC-MSCs also modulated systemic inflammatory mediators. No studies were rated as low risk across all SYCLE domains. These results demonstrate the efficacy of UC-MSC treatment in preclinical sepsis models and highlight their potential as a therapeutic intervention for septic shock.

Cell-based Therapies for Acute Respiratory Distress Syndrome: Where Are We Now?

There is considerable interest in the potential for cell-based therapies, particularly mesenchymal stromal cells (MSCs) and their products, as a therapy for acute respiratory distress syndrome (ARDS). MSCs exert effects via diverse mechanisms including reducing excessive inflammation by modulating neutrophil, macrophage and T-cell function, decreasing pulmonary permeability and lung edema, and promoting tissue repair. Clinical studies indicate that MSCs are safe and well tolerated, with promising therapeutic benefits in specific clinical settings, leading to regulatory approvals of MSCs for specific indications in some countries.This perspective reassesses the therapeutic potential of MSC-based therapies for ARDS given insights from recent cell therapy trials in both COVID-19 and in 'classic' ARDS, and discusses studies in graft-vs.-host disease, one of the few licensed indications for MSC therapies. We identify important unknowns in the current literature, address challenges to clinical translation, and propose an approach to facilitate assessment of the therapeutic promise of MSC-based therapies for ARDS.

Targeted transcriptomic analysis of synovial tissues from horses with septic arthritis treated with immune-activated mesenchymal stromal cells reveals induction of T-cell response pathways.

To investigate mechanistically the reported beneficial effects of immune-activated mesenchymal stromal cell (MSC) therapy to treat equine septic arthritis, leveraging Nanostring technology. 8 Quarter Horses with induced tibiotarsal Staphylococcus aureus septic arthritis treated IA with either Toll-like receptor-3 agonist polyinosinic:polycytidylic acid-activated MSCs + vancomycin antimicrobials (TLR-MSC-VAN; n = 4) or antimicrobials (VAN; 4). Synovial tissues were collected and fixed in neutral-buffered 10% formalin, and formalin-fixed paraffin-embedded synovial and osteochondral tissues were sequenced using a custom-designed 200-gene equine Nanostring nCounter immune panel to directly quantify expression of key immune and cartilage-related genes. Immunohistochemistry to detect CD3+ T cells was performed on synovial tissues to further quantify T-cell infiltration in TLR-MSC-VAN- versus VAN-treated joints. Comparison of synovial transcriptomes between groups revealed moderate changes in differential gene expression, with upregulated expression of 9 genes and downregulated expression of 17 genes with fold change ≥ 2 or ≤ -2 and a significant false discovery rate-adjusted P value of ≤ .05. The most upregulated genes in TLR-MSC-VAN-treated horses included those related to T-lymphocyte recruitment and function, while pathways related to innate immune activation and inflammation were significantly downregulated. Immunohistochemistry and quantitation of CD3+ T-cell infiltrates revealed a numerically greater infiltrate in synovial tissues of TLR-MSC-VAN-treated horses, which did not reach statistical significance in this small sample set (P = .20). Targeted transcriptomic analyses using an equine Nanostring immune and cartilage health panel provided new mechanistic insights into how innate and adaptive immune cells within synovial tissues respond to TLR-activated MSC treatment when used to treat septic arthritis.

P967 Allogeneic bone marrow-derived mesenchymal stromal cell therapy for complex perianal and rectovaginal fistulas in Crohn´s disease: a retrospective single-centre study

Abstract Background Perianal fistulising Crohn´s disease (CD) is associated with a high burden of disease and treatment of fistulas remains challenging. Promising data on short-term efficacy of bone marrow-derived mesenchymal stromal cell (bmMSC) treatment emerged in the recent past, but there is limited data regarding long-term efficacy and safety. Methods Between February 2013 and January 2016, patients with non-active CD (Harvey-Bradshaw Index < 5) and draining complex, treatment-refractory perianal or rectovaginal fistulas underwent local bmMSC therapy as compassionate use. After curettage of the fistula tract, patients received three local bmMSC injections biweekly with 20 million cells each. In case of incomplete clinical and radiological healing 3 to 12 months after the first treatment, up to six additional injections with 40 million cells each were administrated, resulting in a maximal cumulative dose of 300 million bmMSC (table 1). We retrospectively analysed patient records for disease course and documentation of adverse events. Clinical remission was defined by closure of external fistula openings without discharge at digital pressure. The modified Van Assche index was assessed before bmMSC treatment as well as in short- and long-term MRI follow-up. Results Six female patients (median age 35 years, range 19 – 46 years) with two or three complex fistulas each were included. In total, 13 fistulas (9 transsphincteric, 2 extrasphincteric and 2 rectovaginal) underwent local bmMSC application (table 1). Median radiological and clinical follow up was 80 months (range, 44 – 98 months) after first local bmMSC injection. 8 of 13 fistulas (62%) exhibited complete closure at last observation. For rectovaginal fistulas, long-term remission was 50 % (1 of 2). Excluding rectovaginal fistulas, 4 of 6 patients (67%) showed long-term closure of all other fistulas. Pelvic MRI showed a decrease in modified Van Assche index from baseline (median score 7.8, range 6.2-9.7) to long-term follow up (median score 2.1, range 1.5-11.7). No immediate adverse events related to bmMSC injections were observed. One patient (p1) was diagnosed with a local adenocarcinoma of the rectum (pT1, pN0, R0) 106 months after first bmMSC injection. MRI control 11 months prior showed complete fistula remission. The tumor exhibited a female karyotype, while bmMSC had been derived from a male volunteer. Conclusion More than 60% of all treatment-refractory CD perianal fistulas showed long-term remission up to 8 years after local allogenic bmMSC therapy.

COVID in the wild and mesenchymal stromal cell therapy.

COVID in the wild and mesenchymal stromal cell therapy.

MAPPING THE SPATIAL AND TEMPORAL HETEROGENEITY OF MESENCHYMAL STROMAL CELLS WHEN USED AS A CELL THERAPY IN OSTEOCHONDRAL REPAIR

Despite osteoarthritis (OA) representing a large burden for healthcare systems, there remains no effective intervention capable of regenerating the damaged cartilage in OA. Mesenchymal stromal cells (MSCs) are adult-derived, multipotent cells which are a candidate for musculoskeletal cell therapy. However, their precise mechanism of action remains poorly understood.The effects of an intra-articular injection of human bone-marrow derived MSCs into a knee osteochondral injury model were investigated in C57Bl/6 mice. The cell therapy was retrieved at different time points and single cell RNA sequencing was performed to elucidate the transcriptomic changes relevant to driving tissue repair. Mass cytometry was also used to study changes in the mouse immune cell populations during repair.Histological assessment reveals that MSC treatment is associated with improved tissue repair in C57Bl/6 mice. Single cell analysis of retrieved human MSCs showed spatial and temporal transcriptional heterogeneity between the repair tissue (in the epiphysis) and synovial tissue. A transcriptomic map has emerged of some of the distinct genes and pathways enriched in human MSCs isolated from different tissues following osteochondral injury. Several MSC subpopulations have been identified, including proliferative and reparative subpopulations at both 7 days and 28 days after injury. Supported by the mass cytometry results, the immunomodulatory role of MSCs was further emphasised, as MSC therapy was associated with the induction of increased numbers of regulatory T cells correlating with enhanced repair in the mouse knee.The transcriptomes of a retrieved MSC therapy were studied for the first time. An important barrier to the translation of MSC therapies is a lack of understanding of their heterogeneity, and the consequent lack of precision in its use. MSC subpopulations with different functional roles may be implicated in the different phases of tissue repair and this work offers further insights into repair process.

Mesenchymal stromal cell response to intervertebral disc-like pH is tissue source dependent.

Intervertebral disc (IVD) degeneration (IVDD) has become increasingly prevalent and is a common contributing factor to low back pain. Current treatment options are limited to either symptom management or surgery. A promising treatment option being explored is intradiscal administration of mesenchymal stromal cells (MSCs). However, there remains a gap in knowledge as to whether MSCs from different tissue sources have similar responses to the low pH microenvironment of the IVD and the possible mechanisms governing these responses. To study this, MSCs from three different tissue sources: adipose (adipose-derived mesenchymal stem cell), bone marrow (bone marrow mesenchymal stem cells), and amnion (amniotic membrane mesenchymal stem cell) were cultured at low pHs representative of IVDD. MSCs were assessed for survival, senescence, apoptosis, metabolic activity, and cytokine release profile. Additionally, western blot was utilized to assess acid sensing ion channel 1 and 3 expression. The results of this study indicated that MSC viability, cell proliferation, senescence, and metabolic activity is negatively affected by low pH and alters MSC cytokine production. This study also demonstrated that MSCs behavior is dependent on tissue source. Understanding how MSC behavior is altered by pH will allow further research aimed at increasing the efficacy of MSC therapy to promote in situ IVDtissue regeneration to combat IVDD.

Effects of preconditioning with TNFα and IFNγ in angiogenic potential of mesenchymal stromal cell-derived extracellular vesicles.

Introduction: Mesenchymal stromal cells (MSCs) have demonstrated therapeutic properties both in vitro and in vivo to treat various diseases, including anti-inflammatory, immunomodulatory and pro-angiogenic effects. These therapeutic effects are mediated by their secretome composed of soluble factors and extracellular vesicles (EVs). The composition of EVs reflects the molecular and functional characteristics of parental cells. MSC preconditioning can alter the composition of EVs, thereby influencing their therapeutic potential. Methods: MSCs were subjected to preconditioning with two cytokines, TNFα and IFNγ. Following 24h of preconditioning, MSC-EVs secreted into the culture supernatant were isolated through tangential filtration. Particle concentration and size distribution were measured by nanoparticle tracking analysis, and the surface antigen expression of the EV-specific CD63 was quantified via Enzyme Linked ImmunoSorbent Assay. The angiogenic potential of MSCEVs obtained after preconditioning MSCs was assessed by the analysis of their protein composition and their influence on human umbilical vein endothelial cell (HUVECs) proliferation, migration, and tube-forming ability. Results: Preconditioning with TNFα and IFNγ did not influence the MSC-EV profile but did induce changes in their protein content. Indeed, the expression of pro-angiogenic proteins increased in EVs from preconditioned MSCs compared to EVs from no-preconditioned MSCs. EVs from preconditioned MSCs tend to stimulate HUVEC migration, proliferation and tubeforming ability. These observations imply the presence of a pro-angiogenic potential in EVs obtained after preconditioning of MSCs with TNFα and IFNγ. Discussion: In conclusion, it appears that the pro-angiogenic potential of EVs is enhanced through preconditioning of MSCs with TNFα and IFNγ. The use of these MSCs-EVs in therapy would circumvent the limitations of current cell-based therapies. Indeed, the therapeutic potential of MSC-EVs presents an attractive strategy for exploiting the clinical benefits of MSC therapy. For example, in the field of regenerative medicine, the exploitation of cell-free therapy using highly pro-angiogenic MSC-EVs is of great interest.

Media matters: culture medium-dependent hypervariable phenotype of mesenchymal stromal cells

BackgroundDespite a long history of investigation and sustained efforts in clinical testing, the number of market authorisations for mesenchymal stromal cell (MSC) therapies remains limited, with none approved by the United States Food and Drug Administration. Several barriers are impeding the clinical progression of MSC therapies, to the forefront of these is a lack of standardised manufacturing protocols which is further compounded by an absence of biologically meaningful characterisation and release assays. A look at clinical trial registries demonstrates the diversity of MSC expansion protocols with variabilities in cell source, isolation method and expansion medium, among other culture variables, making it extraordinarily difficult to compare study outcomes. Current identification and characterisation standards are insufficient; they are not specific to MSCs and do not indicate cell function or therapeutic action.MethodsThis work analysed the influence of five widely used culture media formulations on the colony-forming potential, proliferation kinetics, trilineage differentiation potential and immunomodulatory potential of human bone marrow-derived MSCs (BM-MSCs). The surface marker expression profiles were also characterised using a high-content flow cytometry screening panel of 243 markers.ResultsSignificant differences in the biological attributes of BM-MSCs including clonogenicity, proliferation, differentiation propensity and immunomodulatory capacity were revealed in response to the composition of the culture medium. Despite their biological differences, all cell preparations uniformly and strongly expressed the standard positive markers proposed for BM-MSCs: CD73, CD90 and CD105. Immunophenotypic profiling revealed that the culture medium also had a significant influence on the surface proteome, with one-third of tested markers exhibiting variable expression profiles. Principal component analysis demonstrated that BM-MSCs isolated and expanded in a proprietary xeno- and serum-free medium displayed the most consistent cell phenotypes with little variability between donors compared to platelet lysate and foetal bovine serum-containing media.ConclusionsThese data suggest that media composition has a highly significant impact on the biological attributes of MSCs, but standard surface marker tests conceal these differences. The results indicate a need for (1) standardised approaches to manufacturing, with an essential focus on defined media and (2) new biologically relevant tests for MSC characterisation and product release.

Human dental pulp stem cells have comparable abilities to umbilical cord mesenchymal stem/stromal cells in regulating inflammation and ameliorating hepatic fibrosis.

Hepatic fibrosis, also called cirrhosis, have wide prevalence worldwide for long yeas. Recently, many treatments for liver cirrhosis made marked progress, especially the umbilical cord-derived mesenchymal stromal cells (UCMSC) therapy. However, limited recourses and potential immune-related issues become the obstacles on UCMSC popularization in clinic. Therefore, we took dental pulp stem cells (DPSCs) into the consideration, since autologous DPSCs can be easily obtained without any ethnic or immune-related issues that heterogenous UCMSCs could encounter. We systematically compared the effects of both cell types and found that DPSCs had similar results to UCMSCs in regulating inflammation and reversing hepatic fibrosis. In our study, co-culturing T cells and PBMSCs showed that DPSCs have the ability to inhibit the proliferation of inflammatory cells and downregulate relevant inflammatory factors. In vitro and in vivo sterility tests confirmed the bio-safety of DPSCs. Moreover, the 1year-aged mouse model demonstrated that DPSCs successfully reversed hepatic fibrosis. Overall, DPSCs demonstrated comparable effectiveness to UCMSCs in regulating inflammation and reversing hepatic fibrosis, particularly in the aged mouse model that represents middle-aged and elderly humans. Since autologous DPSCs avoid potential immune-related issues that heterogenous UCMSCs could encounter, they may be a better choice for stem cell-related therapies.

Abstract 15640: Long Term Event-Free Survival in Patients With Ischemic and Non-Ischemic Cardiomyopathy up to Thirteen Years Following Cell-Based Therapy: Results From the Hyperion Observational Cohort

Introduction: The long-term clinical outcomes of cell-based therapies to treat ischemic (ICM) and non-ischemic dilated cardiomyopathy (NIDCM) are unknown. We therefore prospectively followed patients (pts) with ICM/NICDM treated by targeted transcatheter endocardial mesenchymal stromal cell (MSC) injections (TESI). Methods: Of the 155 pts enrolled in prior MSC TESI studies, 111 were eligible to be contacted. Of these, 47 (42%) agreed to participate and have periodic follow-up assessments (Cardiac MRI/CT, 6MWT, labs, PE, EKG, and MLHFq) for up to 13 years following their index procedure. Time-to-event information was captured from all 155 former participants. Endpoints included event-free survival, changes in left ventricular ejection fraction (EF), and ventricular remodeling. Clinical endpoint events were defined as the composite of: Death (all-cause mortality), Left Ventricular Assist Device (LVAD) placement, or Heart Transplant. Descriptive statistics were used to classify the sample, and Kaplan-Meier survival analysis was generated to examine time-to-event trends. Results: There were 134 men and 21 women, mean age 60.0±11.0 years, including 121 (78%) with ICM, and 34 (22%) with NIDCM. In pts with ICM, mean EF at baseline was 31 %±10.8% and after 1 year was 32.6%±11.8% (P=0.08). In pts with NIDCM baseline EF was 27%±10% and increased to 34%±13% after 1 year (P=0.002). Overall, 40% of pts had a decrease in LVEF, 26% had <5% increase, 34% had a ≥5% increase, and 17% had a ≥10% increase in LVEF after 1 year. Increases of ≥5% LVEF post-therapy were associated with longer event-free survival in NIDCM (OR: 2.57; 95% CI: 0.6, 11.1) but not ICM (OR: 1.25; 95% CI: 0.4, 3.6). Conversely, reductions in LVEDV were associated with longer event-free survival in ICM (OR: 7.23; 95% CI: 1.9, 27.1) but not NIDCM (OR: 1.88; 95% CI: 0.4, 10.0). Conclusion: In this long-term observational cohort analysis, improvement of EF and/or reduction in LVEDV was associated with survival benefits among pts with NIDCM and ICM respectively. Future studies are needed with placebo controls to determine which pts are most likely to respond to MSC therapy. Clinical Trial Registration: URL: http://www.clinicaltrials.gov.; Unique ID: NCT03071835.

Cell-free DNA measurement of three genomes after allogeneic MSC therapy in kidney transplant recipients indicates early cell death of infused MSC.

Mesenchymal stromal cell (MSC) therapy is a promising treatment that allows for drug minimization in clinical kidney transplantation. While it is thought that MSCs rapidly go into apoptosis after infusion, clinical evidence for this is scarce since methods to detect cell death of infused cells in vivo are lacking. Cell-free DNA (cfDNA) has recently gained attention as a biomarker for cell death. In this study, we longitudinally measured cfDNA in plasma samples of the recipient, kidney donor, and allogeneic third-party MSC in the context of the Neptune study. cfDNA levels were measured at several time points before and after allogeneic MSC infusion in the 10 recipients who participated in the Neptune study. cfDNA ratios between the recipient, kidney graft, and MSC were determined. We observed a peak in MSC-derived cfDNA 4 h after the first and second infusions, after which MSC-derived cfDNA became undetectable. Generally, kidney graft-derived cfDNA remained in the baseline-level range. Our results support preclinical data that MSC are short-lived after infusion, also in a clinical in vivo setting, and are relevant for further research into the mechanism of action of MSC therapy.

Extracellular vesicles in osteoarthritis: from biomarkers to therapeutic potential

Equine osteoarthritis is a leading welfare concern. Currently, it can only be diagnosed in its late stages – radiographically and upon clinical examination. There are no curative therapeutic options, with treatment aiming to provide symptom relief and reduce the rate of progression. Thus far, no biochemical diagnostic panels have been produced to diagnose osteoarthritis in its infancy, nor have there been transformative therapeutics to improve disease management. As such, the exploration has continued, with attention now focused on the emerging role of extracellular vesicles in the pathogenesis of osteoarthritis, their potential to carry biomarkers of disease and their therapeutic capacity in the context of popular regenerative therapeutics, such as mesenchymal stromal cell therapy. This article provides a brief overview of the role of extracellular vesicles in equine osteoarthritis for veterinary clinicians, and the future directions this growing field may explore.

Transient Fever: the Sole Treatment-Related Adverse Event associated with Mesenchymal Stromal Cells and Solid Clues from the Real World.

The number of trials investigating mesenchymal stromal cells (MSCs) soars within 3 years which urges a study analysing emerging MSC treatment-related adverse events. To assess the safety of MSC therapy and provide solid evidence for clinical translation of MSC. A meta-analysis of randomized clinical trials (RCTs) published up to April 20th, 2023 was performed. Odds ratio (OR) and 95% confidential intervals (CIs) were used to display pooled results. 152 randomized clinical trials (RCTs) that incorporated 9228 individuals treated with MSCs from autologous or allogenic adipose tissue, bone marrow, Wharton's Jelly, and placenta tissue were included in the analysis. We discovered appropriate 21 MSC treatment-related adverse events (TRAEs), of which fever [OR, 1.61, 95% CI: 1.22-2.11, p<0.01] was the sole event that was closely associated with MSC therapy. MSCs also trended to lower the incidence rate of tachycardia [OR, 0.83, 95% CI: 0.64-1.09, p=0.14] and fatigue [OR, 0.18, 95% CI: 0.61-1.07, p=0.18]. A separate analysis of studies with long-term follow-up (more than 1 year) demonstrated the close relationship between MSCs and fever [OR, 1.75, 95% CI: 1.26-2.24, p<0.01]. The rest TRAEs did not associate themselves with MSC therapy. Dose-response was also conducted for fever, linearity was discovered between MSCs from allogeneic tissue and Wharton's Jelly and fever. To date, our results suggest that fever is the only AE closely associated with MSCs.

Adipose stromal cells bioproducts as cell-free therapies: manufacturing and therapeutic dose determine in vitro functionality

BackgroundExtracellular vesicles (EV) are considered a cell-free alternative to mesenchymal stromal cell (MSC) therapy. Numerous reports describe the efficacy of EV in conferring immunomodulation and promoting angiogenesis, yet others report these activities to be conveyed in EV-free bioproducts. We hypothesized that this discrepancy may depend either on the method of isolation or rather the relative impact of the individual bioactive components within the MSC secretome.MethodsTo answer this question, we performed an inter-laboratory study evaluating EV generated from adipose stromal cells (ASC) by either sequential ultracentrifugation (UC) or size-exclusion chromatography (SEC). The effect of both EV preparations on immunomodulation and angiogenesis in vitro was compared to that of the whole secretome and of the EV-free protein fraction after SEC isolation.ResultsIn the current study, neither the EV preparations, the secretome or the protein fraction were efficacious in inhibiting mitogen-driven T cell proliferation. However, EV generated by SEC stimulated macrophage phagocytic activity to a similar extent as the secretome. In turn, tube formation and wound healing were strongly promoted by the ASC secretome and protein fraction, but not by EV. Within the secretome/protein fraction, VEGF was identified as a potential driver of angiogenesis, and was absent in both EV preparations.ConclusionsOur data indicate that the effects of ASC on immunomodulation and angiogenesis are EV-independent. Specific ASC-EV effects need to be dissected for their use as cell-free therapeutics.

Differential response of mesenchymal stromal cells (MSCs) to type 1 ex vivo cytokine priming: implications for MSC therapy

Background aimsMesenchymal stromal cells (MSCs) are polymorphic, adherent cells with the capability to stimulate tissue regeneration and modulate immunity. MSCs have been broadly investigated for potential therapeutic applications, particularly immunomodulatory properties, wound healing and tissue regeneration. The exact physiologic role of MSCs, however, remains poorly understood, and this gap in knowledge significantly impedes the rational development of therapeutic cells. Here, we considered interferon γ (IFN-γ) and tumor necrosis factor alpha (TNF-α), two cytokines likely encountered physiologically and commonly used in cell manufacturing. For comparison, we studied interleukin-10 (IL-10) (anti-inflammatory) and interleukin-4 (IL-4) (type 2 cytokine). MethodsWe directly assessed the effects of these cytokines on bone marrow MSCs by comparing RNA Seq transcriptional profiles. Western blotting and flow cytometry were also used to evaluate effects of cytokine priming. ResultsThe type 1 cytokines (IFN-γ and TNF-α) induced striking changes in gene expression and remarkably different profiles from one another. Importantly, priming MSCs with either of these cytokines did not increase variability among multiple donors beyond what is intrinsic to non-primed MSCs from different donors. IFN-γ–primed MSCs expressed IDO1 and chemokines that recruit activated T cells. In contrast, TNF-α–primed MSCs expressed genes in alternate pathways, namely PGE2 and matrix metalloproteinases synthesis, and chemokines that recruit neutrophils. IL-10 and IL-4 priming had little to no effect. ConclusionsOur data suggest that IFN-γ–primed MSCs may be a more efficacious immunosuppressive therapy aimed at diseases that target T cells (ie, graft-versus-host disease) compared with TNF-α–primed or non-primed MSCs, which may be better suited for therapies in other disease settings. These results contribute to our understanding of MSC bioactivity and suggest rational ex vivo cytokine priming approaches for MSC manufacturing and therapeutic applications.