Stem cells out of the bag: characterization of ex vivo expanded mesenchymal stromal cells for possible clinical use

AIM: Mesenchymal stromal cells (MSC) are a promising tool for cellular therapy and regenerative medicine. One major difficulty in establishing a MSC expansion protocol is the large volume of bone marrow (BM) required. We studied whether cells trapped within a collection bag and filter system could be considered as a source of MSC. RESULTS: From the 20 BM collection bag and filter systems, we recovered an average of 1.68 × 10(8) mononuclear cells, which is the equivalent to 60 ml of filtered BM. Mononuclear cells were expanded ex vivo to 17 × 10(6) MSC, with purity shown by a CD44(+), CD105(+), CD90(+) and CD73(+) immunophenotype, a reduction of 20% proliferating cells in a mixed lymphocyte reaction and also the ability of adipocyte differentiation. CONCLUSION: Long-term MSC cultures were established from the usually discarded BM collection bag and filter, maintaining an appropriate phenotype and function, being suitable for both investigation and clinical settings.