Poster 106: Commonly Used Orthopaedic Clinical Therapeutics Affect the Cytokine Activity of Culture-Expanded Mesenchymal Stem Cells

OBJECTIVES: Hyaluronic acid (HA), platelet-rich plasma (PRP), and methylprednisolone are widely used for the non-operative management of osteoarthritis (OA). More recently, human bone marrow derived mesenchymal stem cells (BM-MSCs) have garnered significant interest as a non-operative means for symptom modification of OA. Anti-inflammatory cytokine secretion is a major component of proposed BM-MSC action. We sought to describe the effect of HA, PRP, and methylprednisolone on the cytokine profile of BM-MSCs at multiple stages of culture expansion. METHODS: Following Institutional Review Board and United States Food and Drug Administration approval, nine BM-MSC cell lines from 4 human donors underwent three stages of culture expansion: passage 2 (P2), passage 3 (P3), and passage 4 (P4). Levels of OA-related cytokines (IL-1β, IL-6, IL-8, IL-10, Stem cell Factor [SCF], Stem Cell Derived Factor-alpha [SDF-α]) were measured using Luminex multiplexing technology. Each of the BM-MSC preparations were evaluated at each passage, 24 hours following exposure to HA, PRP, or methylprednisolone. Paired T-tests and Wilcoxon signed-rank testing were performed as appropriate following assessment of normality. Significance was set at p<0.05. RESULTS: Culture expansion significantly altered cytokine production, however treatment with current OA therapeutics further altered these responses implicating the potential of combined treatment of culture expanded hMSCs and OA therapeutics. Figure 1 demonstrates the behavior of selected cytokines after exposure to HA, PRP or methylprednisolone preparations. Further, we tested different concentrations of each of the therapeutics to determine optimal dosing. Exposure to increasing doses of HA led to reductions in BM-MSC expression of SCF, SDF-α, VEGF, CCL20, and adiponectin (p<0.05 for all). PRP increased IL-1 levels in P2 and P3 (p<0.05 for both), IL-6 in P2 (100 pg/mL vs 5500 pg/mL, p<0.001), and IL-8 in P3 (900 pg/mL vs 3900 pg/mL, p<0.001). PRP did not affect IL-10 expression (p>0.05). Aside from an increase in IL-6 production for P2 (200 pg/mL vs 1500 pg/mL, p<0.05), methylprednisolone did not have significant effects on cytokine expression. CONCLUSIONS: Orthopaedic therapeutic adjuvants influence the inflammatory cytokine profile of BM-MSCs at multiple stages of culture expansion. Although further study is needed, these therapeutics have potential to be used in tandem with BM-MSCs to create an optimal cytokine environment for treatment of degenerative joint disease.