Abstract
Introduction
Mesenchymal stem cells (MSCs) are a potential source of cells for the repair of articular cartilage and osteochondral defects (OCD) in the ankle. Synovial tissue has been shown to be a rich source of MSCs with the ability to undergo chondrogenic differentiation. Although these cells represent a heterogenous population, clonal populations have not been previously studied.
Methods
MSCs were isolated from synovial tissue of a patient undergoing joint arthroplasty and expanded in culture. Six clonal populations were also isolated and expanded. The cells from the mixed parent population and the derived clonal populations were characterised for stem cell surface epitopes, and then cultured in chondrogenic mediums. Various assays were determined to analyse for features of differentiation.
Results
Cells from the mixed parent population and the derived clonal populations stained strongly for markers of adult mesenchymal stem cells including CD44, CD90 and CD105, and they were negative for the haematopoietic marker CD34 and for the neural and myogenic marker CD56. Interestingly, a variable number of cells were also positive for the pericyte marker 3G5 both in the mixed parent and clonal populations. The clonal populations exhibited a variable chondrogenic response.
Conclusion
Pericytes are a candidate stem cell in many tissues and our results show that all six clonal populations derived from the heterogenous synovium population express the pericyte marker 3G5. The chondrogenic potential of synovial tissue could be optimised by the identification of clonal populations with a propensity to differentiate down particular differentiation pathways. Our study demonstrates a role for MSCs in of osteochondral defects (OCDs) and areas of focal cartilage damage in the ankle joint.
