IJOTM 2008-6490 3 1 2012 01 03 Human Bone Marrow-derived Mesenchymal Stem Cell: A Source for Cell-Based Therapy 32 39 EN M Ayatollahi Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. ayatollmb@yahoo.com B Geramizadeh M Zakerinia M Ramzi R Yaghobi P Hadadi AR Rezvani M Aghdai N Azarpira H Karimi 2011 10 04 Background: The ability of mesenchymal stem cells (MSCs) to differentiate into many cell types, and modulate immune responses, makes them an attractive therapeutic tool for cell transplantation and tissue engineering. Objective: This project was designed for isolation, culture, and characterization of human marrow-derived MSCs based on the immunophenotypic markers and the differentiation potential. Methods: Bone marrow of healthy donors was aspirated from the iliac crest. Mononuclear cells were layered over the Ficoll-Paque density-gradient and plated in tissue cultures dish. The adherent cells expanded rapidly and maintained with periodic passages until a relatively homogeneous population was established. The identification of adherent cells and the immune-surface markers was performed by flow cytometric analysis at the third passage. The in vitro differentiation of MSCs into osteoblast and adipocytes was also achieved. Results: The MSCs were CD11b (CR3), CD45, CD34, CD31 (PCAM-1), CD40, CD80 (B7-1), and HLA-class II negative because antigen expression was less than 5%, while they showed a high expression of CD90, and CD73. The differentiation of osteoblasts, is determined by deposition of a mineralized extracellular matrix in the culture plates that can be detected with Alizarin Red. Adipocytes were easily identified by their morphology and staining with Oil Red. Conclusion: MSCs can be isolated and expanded from most healthy donors, providing for a source of cell-based therapy.