Encapsulation of allogeneic mesenchymal stem cells in alginate extends local presence and therapeutic function.

Bone marrow derived mesenchymal stem cells (MSCs) have immunomodulatory and trophic capacities. For therapeutic application in local chronic inflammatory diseases, MSCs, preferably of allogeneic origin, have to retain immunomodulatory properties. This might be achieved by encapsulation of MSCs in a biomaterial that protects them from the host immune system. Most studies investigating the properties of MSCs for therapeutic application use short term cultures of cells in monolayer. Since the physical environment of MSCs can influence their functionality, we evaluated the feasibility of preserving the immunomodulatory properties of MSCs encapsulated in a three-dimensional alginate construct. After 5 weeks of implantation in immunocompetent rats, active allogeneic MSCs encapsulated in alginate were still detectable by Bio Luminescence Imaging and Magnetic Resonance Imaging of luciferase transduced and superparamagnetic iron oxide labelled MSCs. MSCs injected in saline were only detectable up to 1 week after injection. Moreover, the MSCs encapsulated in alginate responded to inflammatory stimuli similarly to MSCs in monolayer culture. In addition, MSC-alginate beads secreted immunomodulatory and trophic factors and inhibited T-cell proliferation after 30 d of in vitro culture. Our data indicate that allogeneic MSCs encapsulated in alginate persist locally and could act as an interactive immunomodulatory or trophic factor release system for several weeks, making this an interesting system to investigate for application in inflammatory disease conditions.

Arthritic and non-arthritic synovial fluids modulate IL10 and IL1RA gene expression in differentially activated primary human monocytes.

OBJECTIVE: Synovitis with an increased presence of macrophages is observed in osteoarthritis (OA) and rheumatoid arthritis (RA). Given the important role of macrophages in arthritis, we investigated the influence of OA and RA synovial fluid (SF) on primary human monocytes (Mo), their lineage precursors. METHOD: Adherent monocytes without any stimulation (Mo(-)) or stimulated with IFN-γ and TNF-α (Mo(IFN-γ/TNF-α)) or IL-4 (Mo(IL-4)) were exposed to SF from 6 donors without any known joint disease (SF-Ctrl), 10 OA donors (SF-OA), and 10 RA donors (SF-RA). The transcriptional expression of IL6, IL1B, TNFA, IL10, CCL18, CD206, and IL1RA was analyzed. RESULTS: Mo(-) exposed to SF-RA had a lower expression of IL10 and a higher expression of IL1RA than when exposed to SF-Ctrl. Mo(IL-4) exposed to SF-RA had a lower expression of IL10 and CCL18 than when exposed to SF-Ctrl and Mo(IFN-γ/TNF-α) were not affected by SF-RA. Mo exposed to SF-OA also expressed less IL10, but only upon stimulation with IL-4, and expressed more IL1RA than when exposed to SF-Ctrl in any condition. CONCLUSION: A lower expression of IL10 may be regarded as a response to less inflammatory conditions since IL10 expression is higher in response to IFN-γ/TNF-α stimulation, probably as a feedback mechanism. Therefore, the lower expression of IL10 and the higher expression of IL1RA in Mo exposed to arthritic than to non-arthritic SF suggest that arthritic SF is mainly reducing the inflammatory responses in Mo. This may mimic the response of monocytes/macrophages recruited to the joint, where feedback mechanisms counteract pro-inflammatory processes.

Safety of intra-articular cell-therapy with culture-expanded stem cells in humans: a systematic literature review.

BACKGROUND: An important goal of stem cell research in orthopaedics is to develop clinically relevant techniques that could be applied to heal cartilage or joint pathology. Stem cell treatment in orthopaedics for joint pathology is promising since these cells have the ability to modulate different processes in the various tissues of the joint simultaneously. The non life-threatening nature of musculoskeletal system disorders makes safety of stem cell therapy a necessary prerequisite. OBJECTIVE: To systematically review the literature and provide an overview of reported adverse events (AEs) of intra-articular treatment with culture-expanded stem cells in humans. DESIGN: A systematic literature search was performed in Pubmed, EMBASE, Web of Science and CINAHL in February 2013. AEs were reported into three categories: local/systemic, serious adverse event or AE (SAE/AE), related/unrelated. RESULTS: 3039 Potentially eligible articles were identified of which eventually eight fulfilled our inclusion criteria. In total, 844 procedures with a mean follow-up of 21 months were analysed. Autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) were used for cartilage repair and osteoarthritis treatment in all included studies. Four SAEs were reported by the authors. One infection following bone marrow aspiration (BMA) was reported as probably related and resolved with antibiotics. One pulmonary embolism occurred 2 weeks after BMA and was reported as possibly related. Two tumours, both not at the site of injection, were reported as unrelated. Twenty-two other cases of possible procedure-related and seven of possible stem cell-product related adverse events (AEs) were documented. The main AEs related to the procedure were increased pain/swelling and dehydration after BMA. Increased pain and swelling was the only AE reported as related to the stem cell-product. CONCLUSIONS: Based on current literature review we conclude that application of cultured stem cells in joints appears to be safe. We believe that with continuous caution for potential side effects, it is reasonable to continue with the development of articular stem cell therapies.