Evolutionary impact assessment is a framework for quantifying the effects of harvest-induced evolution on the utility generated by fish stocks.

Mesenchymal stem or stromal cells (MSCs) exert chondroprotective effects in preclinical models of osteoarthritis (OA). Most of their therapeutic effects are mediated via soluble mediators, which can be conveyed within extracellular vesicles (EVs). The objective of the study was to compare the respective role of exosomes (Exos) or microvesicles/microparticles (MPs) in OA. MPs and Exos were isolated from bone marrow murine BM-MSCs through differential centrifugation. Effect of MPs or Exos was evaluated on OA-like murine chondrocytes and chondroprotection was quantified by RT-qPCR. In OA-like chondrocytes, BM-MSC-derived MPs and Exos could reinduce the expression of chondrocyte markers (type II collagen, aggrecan) while inhibiting catabolic (MMP-13, ADAMTS5) and inflammatory (iNOS) markers. Exos and MPs were also shown to protect chondrocytes from apoptosis and to inhibit macrophage activation. In vivo, Exos or MPs were injected in the collagenase-induced OA (CIOA) model and histomorphometric analyses of joints were performed by µCT and confocal laser microscopy. BM-MSCs, MPs and Exos equally protected mice from joint damage. In conclusion, MPs and Exos exerted similar chondroprotective and anti-inflammatory function in vitro and protected mice from developing OA in vivo, suggesting that either Exos or MPs reproduced the main therapeutic effect of BM-MSCs.

Mesenchymal stem cells (MSCs) exert immunomodulatory properties via the inhibition of T cell activation and proliferation. Because of the deleterious role of Th17 cells in the pathogenesis of inflammatory disease, we investigated whether proinflammatory cytokines could modify the expression of adhesion molecules on human MSCs, thereby contributing to increased Th17 cell adhesion to MSCs and, as a consequence, modulating the function of the latter cells. IFN-γ and TNF-α synergistically enhanced the expression of CD54 by MSCs, enabling the CCR6 chemokine ligand CCL20 to induce in vitro adhesion of Th17 cells to MSCs. MSCs prevented the in vitro differentiation of naive CD4⁺ T cells into Th17 cells and inhibited the production of IL-17, IL-22, IFN-γ, and TNF-α by fully differentiated Th17 cells; this was mediated, in part, via PGE₂, the production of which was enhanced in cocultures with Th17 cells. Moreover, MSCs induced the production of IL-10 and trimethylation of histone H3K4me3 at the promoter of the FOXP3 gene locus, whereas it suppressed trimethylation of the corresponding region in the RORC gene in Th17 cells. These epigenetic changes were associated with the induction of fork head box p3 and the acquisition by Th17 cells of the capacity to inhibit in vitro proliferative responses of activated CD4⁺ T cells, which was enhanced when MSCs were preincubated with IFN-γ and TNF-α. These results showed that, under inflammatory conditions, MSCs mediate the adhesion of Th17 cells via CCR6 and exert anti-inflammatory effects through the induction of a T cell regulatory phenotype in these cells.

Osteoarthritis (OA) is the most widespread musculoskeletal disorder in adults. It leads to cartilage damage associated with subchondral bone changes and synovial inflammation, causing pain and disability. The present study aimed at evaluating the safety of a dose-escalation protocol of intra-articular injected adipose-derived stromal cells (ASCs) in patients with knee OA, as well as clinical efficacy as secondary endpoint. A bicentric, uncontrolled, open phase I clinical trial was conducted in France and Germany with regulatory agency approval for ASC expansion procedure in both countries. From April 2012 to December 2013, 18 consecutive patients with symptomatic and severe knee OA were treated with a single intra-articular injection of autologous ASCs. The study design consisted of three consecutive cohorts (six patients each) with dose escalation: low dose (2 × 106 cells), medium dose (10 × 106), and high dose (50 × 106). The primary outcome parameter was safety evaluated by recording adverse events throughout the trial, and secondary parameters were pain and function subscales of the Western Ontario and McMaster Universities Arthritis Index. After 6 months of follow-up, the procedure was found to be safe, and no serious adverse events were reported. Four patients experienced transient knee joint pain and swelling after local injection. Interestingly, patients treated with low-dose ASCs experienced significant improvements in pain levels and function compared with baseline. Our data suggest that the intra-articular injection of ASCs is a safe therapeutic alternative to treat severe knee OA patients. A placebo-controlled double-blind phase IIb study is being initiated to assess clinical and structural efficacy. Significance: Although this phase I study included a limited number of patients without a placebo arm, it showed that local injection of autologous adipose-derived stem cells was safe and well tolerated in patients with knee osteoarthritis. This study also provides encouraging preliminary evidence of efficacy. Larger and controlled long-term studies are now mandatory to confirm whether this new strategy of cell therapy can improve pain and induce structural benefit in osteoarthritis.

Objectives: Mesenchymal stem cells (MSCs) release extracellular vesicles (EVs) that display a therapeutic effect in inflammatory disease models. Although MSCs can prevent arthritis, the role of MSCs-derived EVs has never been reported in rheumatoid arthritis. This prompted us to compare the function of exosomes (Exos) and microparticles (MPs) isolated from MSCs and investigate their immunomodulatory function in arthritis.