Mesenchymal stem cells derived from bone marrow and leukapheresis show different putative subpopulations

Mesenchymal stem cells (MSCs), with their high proliferative and differentiation potential, in addition to their plasticity, are promising candidates for cell therapeutic applications. Bone marrow (BM) harvest is still the main source of MSCs in spite of being traumatic and painful. Clinical indications for peripheral blood-derived MSCs are rapidly increasing. This study was done to compare the biological properties of MSCs derived from BM and leukapheresis product regarding viability, fold expansion, cell cycle status and putative subpopulations. MSCs were isolated and cultured from BM and leukapheresis samples after stem cell mobilization. MSCs were characterized by morphology and immunophenotyping. Their viability, fold expansion and cell cycle status were compared. Estimation of putative cells among the mesenchymal population was done by dual expression of CD44 and Oct4. Leukapheresis derived MSCs were found to be comparable to BM-MSCs regarding their viability, fold expansion and cell cycle status, however they differ in their putative subpopulations. BM samples had significantly higher percentage of putative population than leukapheresis samples (18.38± 3.21% vs 5.43± 1.26%, P=0.009). These results indicated the possible isolation and expansion of MSCs from leukapheresis samples. The lower putative subpopulations among leukapheresis derived MSCs may be due to lack of BM microenvironment related factors needed to maintain pluripotency or due to the current methods of cell mobilization that have been optimized for hematopoietic stem cells rather than MSCs.