Isolation and phenotypic characterisation of stem cells from late stage osteoarthritic mesenchymal tissues.

INTRODUCTION Osteoarthritis (OA) represents an increasing health issue worldwide. Regenerative medicine (RM) has raised the hope for introducing revolutionary therapies in clinical practice. Detection of autologus cell sources can improve accessibility to RM strategies. OBJECTIVES To assess the presence and biological potential of mesehchymal stem cells in three tissues (subchondral bone, synovial layer, periarticular adipose tissue) in late stages osteoarthritic patients. MATERIAL AND METHODS Samples were collected from subjects undergoing total knee replacement (TKR). MSCs were isolated and cultured in complete αMEM with β FGF. Cell morphology and growth potential was assessed. Flow cytometry was used for detection of several relevant cell surface markers. Quantitative and qualitative assessment of differentiation potential towards three mesenchymal lineages (osteogenesis adipogenesis chondrogenesis) was performed. Time lapse life cell imaging of nondiferentiated cells over 24 hours period was used to determine cell kinetics. RESULTS Mesenchymal cells derived from all donors and tissue types showed morphology, growth and surface cell markers associated with stemness. All cell types underwent differentiation toward three mesenchymal lineages with significant differences between tissues of origin, not between donors. Cell kinetics, as derived from life imaging records, was variable with tissue of origin, significant higher for adipose derived MSCS. CONCLUSION Human late stage OA mesenchymal tissues, contain progenitors with proliferative and differentiation potential of MSCs. These populations can be used for research and autologus regenerative therapies. Further comparative studies with age matched non OA samples has the potential of contributing to deepening knowledge about disease occurrence and progression.