Autologous synovial fluid enhances migration of mesenchymal stem cells from synovium of osteoarthritis patients in tissue culture system.

Synovial fluid from osteoarthritic knee contains mesenchymal stem cells (MSCs). One of the possible reservoirs of MSCs in synovial fluid is synovial tissue, and synovial fluid may induce mobilization of MSCs into synovial fluid in osteoarthritis patients. Here, we investigated whether synovial fluid expanded synovial MSCs in a tissue culture system. Human synovium and synovial fluid were obtained from osteoarthritis patients during total knee arthroplasties. In the tissue culture system, autologous synovial fluid expanded synovial cells statistically higher than alpha MEM + FBS, and the addition of TGF beta 3 to alpha MEM + FBS increased expansion to a similar level in all 11 donors. The addition of decorin or anti-TGFbeta neutralizing antibody to synovial fluid partially inhibited synovial cell expansion. In cell culture assay, synovial fluid proliferated synovial cells fewer than alpha MEM + FBS. The expanded synovial cells in synovial fluid retained multipotentiality and showed surface markers similar to those of MSCs. We demonstrated that autologous synovial fluid enhanced expansion of MSCs in tissue culture of synovium from osteoarthritis patients by promoting cell migration. This effect was partially affected by TGFbeta.