Multipotential stromal cell (MSC) differentiation and immunophenotyping. (A) Representative images show trilineage differentiation capacity of Heberden’s node (HN)-MSCs compared with synovial fluid (SF)- and iliac crest bone marrow (ICBM)-MSCs. Adipogenesis of HN-MSC was low, and only micro-vesicles were observed (insert). (B) Plot showing mean percentage of populations positive for cell surface markers by flow cytometry (n = 3 for HN-, SF- and ICBM-MSCs). Error bars represent standard deviation. Below are example histogram overlays of Heberden’s node (blue), synovial fluid (green), and bone marrow (red) MSCs with isotype control (grey-filled).