Adult bone marrow is a rich source of human mesenchymal ‘stem’ cells but umbilical cord and mobilized adult blood are not

In postnatal life, mesenchymal stem cells (MSC) self-replicate, proliferate and differentiate into mesenchymal tissues, including bone, fat, tendon, muscle and bone marrow (BM) stroma. Possible clinical applications for MSC in stem cell transplantation have been proposed. We have evaluated the frequency, phenotype and differentiation potential of MSC in adult BM, cord blood (CB) and peripheral blood stem cell collections (PBSC). During culture, BM MSC proliferated to confluence in 10-14 d, maintaining a stable non-haemopoietic phenotype, HLA class-1+, CD29+, CD44+, CD90+, CD45-, CD34- and CD14 through subsequent passages. Using the colony forming unit fibroblasts assay, the estimated frequency of MSC in the BM…