Chondrogenic potential of blood-acquired mesenchymal progenitor cells.

INTRODUCTION: The associated morbidity from the acquisition of mesenchymal stem cells (MSC) from the bone marrow has led to the investigation of alternative stem cell sources. We propose that such cells may be isolated from non-mobilised blood and demonstrate their differentiation into a chondrocytic lineage. This safe and abundant source of cells may be useful for tissue engineering cartilage. METHOD: Peripheral blood mononuclear cells (PBMC) were isolated from healthy adults and cultured in RPMI medium supplemented with serum. The non-adherent and adherent cells were analysed for cell surface marker expression of CD14, CD34, CD133, CD105 and CD45 by flow cytometry. Adherent cells were also cultured on glass slides in chondrogenic media and analysed for the expression of collagen I and II on day 14 of culture. RESULTS: The adherent cells were fibroblastic in morphology and were confluent on day 14. The non-adherent and adherent cell populations were shown to have distinct profiles by flow cytometry. The adherent cells were positive for CD105 and CD14 and also expressed collagen I and II precursors when cultured in chondrogenic media. CONCLUSION: Blood-acquired mesenchymal progenitor cells (BMPCs) can be isolated from non-mobilised blood. These unique cells are CD105(+) and CD14(+) and have chondrogenic differentiation capacity. BMPC may provide a potential source of MPC for tissue engineering applications.