Ageing of bone marrow and umbilical cord derived MSC during culture expansion

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S.F.H. de Witte, E.E. Lambert, A.M. Merino Rodriguez, T. Strini, J.C.W. Douben, S.J. Elliman, P.N. Newsome, J.E.M.M. de Klein, C.C. Baan, M.J. Hoogduijn

Chair(s): Prof. dr. C.C. Baan & dr. M.R. Rookmaaker

Wednesday 8 march 2017

18:06 - 18:18h at Hendrik Marsmanzaal

Categories: Parallel - Basaal

Parallel session: Parallelsessie V – Basaal 1 - Analyse niet-hematopoietische cellen in orgaantransplantatie

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Mesenchymal stromal cells (MSC) are used as experimental immunotherapy. Extensive culture expansion is necessary to obtain clinically relevant cell numbers, although the impact of this on MSC stability and function is unclear. Also, for clinical standardization it is relevant to identify up until when MSC maintain their properties to secure therapeutic efficacy. Here we study the effects of long-term in vitro culture expansion on the stability and function of MSC.

Human bone marrow derived MSC (bmMSC) and umbilical cord derived MSC (ucMSC) were in vitro expanded. During expansion their proliferative capacity was examined. At passages 4, 8 and 12 multiple analyses were carried out on MSC cultures to investigate the ploidy, metabolic stability, telomere length and immunophenotype. In addition, their potential to suppress lymphocyte proliferation and susceptibility to NK cell lysis was examined by FACS.

Both bmMSC and ucMSC showed decreasing proliferative capacity over time, whilst their telomere lengths and mitochondrial activity remained stable. The percentage of aneuploidy in cultures was unchanged after extensive expansion. In addition, expression of MSC markers CD13, CD73, CD90, CD105 and markers potentially associated with stress or ageing such as HLA type I and II and PDL-1 remained unchanged in both cultures. Reduced suppression of CD4 and CD8 T-cell proliferation was observed at passage 8 and 12 ucMSC compared to passage 4. Finally, susceptibility of bmMSC and ucMSC to NK cell lysis was similar among all passages.

We showed that after long-term expansion, the phenotype of bmMSC and ucMSC remains stable and cells exhibit similar immunogenic properties compared to lower passage cells. However, the immunosuppressive properties of MSC are reduced after long term culture. These findings reveal the consequences of application of higher passage MSC in the clinic, which will indeed help increase the total yield of therapeutic MSC, but may interfere with their efficacy.