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Stem Cells International
Volume 2016, Article ID 1764938, 8 pages
Research Article

Clumping and Viability of Bone Marrow Derived Mesenchymal Stromal Cells under Different Preparation Procedures: A Flow Cytometry-Based In Vitro Study

1Institute of Clinical Medicine-Neurology, University of Eastern Finland, 70210 Kuopio, Finland
2Department of Clinical Microbiology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland
3Fraunhofer Institute for Cell Therapy and Immunology, 04103 Leipzig, Germany
4Fraunhofer Research Institution for Marine Biotechnology, 23562 Lübeck, Germany
5Institute for Medical and Marine Biotechnology, University of Lübeck, 23562 Lübeck, Germany
6Finnish Red Cross Blood Service, Advanced Cell Therapy Centre, 00310 Helsinki, Finland
7Neurocenter, Neurology, University Hospital of Kuopio, 70210 Kuopio, Finland

Received 27 November 2015; Revised 15 January 2016; Accepted 4 February 2016

Academic Editor: Shinn-Zong Lin

Copyright © 2016 Li-li Cui et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Complications of microocclusions have been reported after intra-arterial delivery of mesenchymal stromal cells. Hence, quantification and efficient limitation of cell clumps in suspension before transplantation is important to reduce the risk. We used a flow cytometry-based pulse-width assay to assess the effects of different cell suspension concentrations (0.2–2.0 × 106/mL), storage solutions (complete growth medium, Dulbecco’s phosphate-buffered saline, and normal saline), storage time in suspension (0–9 h), and freeze-thawing procedure on the clumping of rat bone marrow derived mesenchymal stromal cells (BMMSCs) and also evaluated cell viability at the same time. Surprisingly, increasing the cell concentration did not result in more cell clumps in vitro. Freshly harvested (fresh) cells in normal saline had significantly fewer cell clumps and also displayed high viability (>90%). A time-dependent reduction in viability was observed for cells in all three storage solutions, without any significant change in the clumping tendency except for cells in medium. Fresh cells were more viable than their frozen-thawed counterparts, and fresh cells in normal saline had fewer cell clumps. In conclusion, cell clumping and viability could be affected by different cell preparation procedures, and quantification of cell clumping can be conducted using the flow cytometry-based pulse-width assay before intra-arterial cell delivery.