Cellular Aging of Mesenchymal Stem Cells

To determine gene expression changes during in vitro senescence of MSC we have analyzed differential expression of the corresponding early passage (P2) and senescent passage (PX). There were global changes in the gene expression profile that were reproducible in three independent donor samples. Keywords: Replicative senescence, time course Mesenchymal Stem Cells (MSC) were isolated from human bone marrow (BM) as described before (Wagner et al., 2005, Exp Hematol, 33, 1402-1416; Wagner et al., Exp Hematol, 34, 536-548). Cells were always replated when grown to confluency. A sample for RNA isolation was taken at every passage until the cells finally became senescent: they became much larger with irregular and flat shape. The nucleus became more circumscribed in phase contrast microscopy. The cytoplasm began to be granular with many inclusions and there was more cell debris. Global gene expression profiles were analyzed to determine molecular changes between corresponding early passage (P2) and senescent passage (PX) in three donor samples. In addition we have analyzed different passages of donor 1 (P2, P3, P4, P5, P6, P7, P8, P10, and P11) to determine changes in the course of cellular aging. Data were median normalized and compared to P2 of the corresponding donor sample.