%0 Journal Article %T Human Mesenchymal Stem Cells Display Reduced Expression of CD105 after Culture in Serum-Free Medium %A Peter Mark %A Mandy Kleinsorge %A Ralf Gaebel %A Cornelia A. Lux %A Anita Toelk %A Erik Pittermann %A Robert David %A Gustav Steinhoff %A Nan Ma %J Stem Cells International %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/698076 %X Human Mesenchymal Stem Cells (hMSCs) present a promising tool for regenerative medicine. However, ex vivo expansion is necessary to obtain sufficient cells for clinical therapy. Conventional growth media usually contain the critical component fetal bovine serum. For clinical use, chemically defined media will be required. In this study, the capability of two commercial, chemically defined, serum-free hMSC growth media (MSCGM-CD and PowerStem) for hMSC proliferation was examined and compared to serum-containing medium (MSCGM). Immunophenotyping of hMSCs was performed using flow cytometry, and they were tested for their ability to differentiate into a variety of cell types. Although the morphology of hMSCs cultured in the different media differed, immunophenotyping displayed similar marker patterns (high expression of CD29, CD44, CD73, and CD90 cell surface markers and absence of CD45). Interestingly, the expression of CD105 was significantly lower for hMSCs cultured in MSCGM-CD compared to MSCGM. Both groups maintained mesenchymal multilineage differentiation potential. In conclusion, the serum-free growth medium is suitable for hMSC culture and comparable to its serum-containing counterpart. As the expression of CD105 has been shown to positively influence hMSC cardiac regenerative potential, the impact of CD105 expression onto clinical use after expansion in MSCGM-CD will have to be tested. 1. Introduction Human MSCs play an essential role in today¡¯s medical research, as they promise new approaches in treatment of human diseases. Their plasticity and immense ex vivo proliferation potential make MSC an important tool for cell transplantation as well as generation of living, functional tissue suitable for organ repair and replacement. Mesenchymal stem cells have already been successfully applied in treatment of osteogenesis imperfecta [1] to limit graft-versus-host disease via immunosuppression [2]. Furthermore, it has been reported that MSCs contribute to the regeneration process after myocardial infarction in mice [3] and are able to improve the outcome of allogeneic transplantation in general by means of immunomodulatory effects [4]. MSCs were first described as plastic adherent, clonogenic, colony-forming fibroblast-like cells [5]. So far, no generally accepted definition of MSC exists, although they are identified by specific properties [6]. The most important is the hMSC ability to self-renew and to give rise to mature cells of adipogenic, osteogenic, and chondrogenic lineage, producing tissues such as bone, cartilage, tendon, adipose tissue, and %U http://www.hindawi.com/journals/sci/2013/698076/