Evaluation of differentiation potential of human bone marrow-derived mesenchymal stromal cells to cartilage and bone cells

Objectives: This study was designed to identify the charac¬teristics and surface antigen properties of mesenchymal stro¬mal cells (MSC) isolated and cultured from bone marrow of healthy subjects and to assess their differentiation potential to osteoblast and chondroblast lineage cells. Methods: Mononuclear cells were isolated by density-gradi¬ent separation from 1-3 ml of bone marrow collected from 10 donors of bone transplantation aged between 4 months and 18 years. These mononuclear cells were cultured in flasks contain¬ing %10 fetal calf serum, which resulted in growth of fibro- blast-like cells showing adhesion onto the culture flask. Physi¬cal properties of the cells were identified and flow cytometric immunophenotyping was performed to specify surface antigen properties. Differentiation of mesenchymal stromal cells in spe¬cific media to chondroblasts and osteoblasts was evaluated. Os- teoblasts and chondroblasts were stained with Alizarin red and Alcian blue, respectively, and microphotographed. Results: In vitro yield of MSCs showed no age-related dif¬ferences in terms of morphological and adhesive properties. While cells of stromal origin showed strong positivity (90% to 99%) to characteristic CD105, CD44, CD166, CD29, CD90, and CD73 antibodies, hematopoietic cells remained negative (0% to 5%) to CD45, CD34, CD14, and HLA-DR antibodies. It was observed that MSCs produced in cell-specific media differentiated to osteoblasts and chondroblasts in all passages (p1-15) tested, including late passages. Conclusion: It seems that the use of MSCs would provide promising treatment strategies in bone marrow transplanta¬tion, inherited diseases, and organ repair; in in vitro assess¬ment of biological effects of biomaterials in orthopedics; and in repair of bone and cartilage injuries.