Synovium-derived mesenchymal stem cells (SMSCs) triple differentiation potentials from healthy donors and patients with rheumatoid arthritis (RA). (A, B) Morphologic characteristics of SMSCs for adipogenic, osteogenic, and chondrogenic differentiation evaluated with the inverted phase-contrast microscope; SMSCs from RA patients (RA-SMSCs) have the same morphologic properties as SMSCs from healthy donors (HD-SMSCs). Adipocytes were filled with many fat vacuoles, and Red Oil O was used to stain the fat vacuoles of adipocytes (A1, B1: ×100). Osteocytes were stained for alkaline phosphatase (ALP) with the Cell ALP assay (A2, B2: ×100) and for calcium deposition by using alizarin red-S (A3, B3: ×100). Chondroblast differentiation from SMSCs was displayed as cartilage-specific metachromasia with alcian blue (A4, B4: ×100).