Isolation of large numbers of mesenchymal stem cells from the washings of bone marrow collection bags: characterization of fresh mesenchymal stem cells.

Background: Bone marrow (BM) is an excellent source of mesenchymal stem cells (MSC) which can be expanded in vitro for further use. However, large volumes of BM specimens are not routinely available. We hypothesized that the normally discarded BM collection kits might be a convenient source of large numbers of MSC.