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

Abstract

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 × 108 mononuclear cells, which is the equivalent to 60 ml of filtered BM. Mononuclear cells were expanded ex vivo to 17 × 106 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.

Keywords

• adipogenic differentiation
• bone marrow
• collection bag
• filter system
• mesenchymal stromal cells
• mixed lymphocyte reaction