Human bone marrow-derived mesenchymal stem cell: a source for cell-based therapy

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. This project was designed for isolation, culture, and characterization of human marrow-derived MSCs based on the immunophenotypic markers and the differentiation potential. 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 adipo-cytes was also achieved. The MSCs were CDllb [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. MSCs can be isolated and expanded from most healthy donors, providing for a source of cell-based therapy