32 Neuß-Stein, Sabine Jahnen-Dechent, Wilhelm 100000 Publikationsserver der RWTH Aachen University Aachen German 109 Bl. : Ill., graph. Darst. Mesenchymal stem cells (hMSC) are suitable for applications in tissue regeneration and tissue engineering. The combination of mesenchymal stem cells with biomaterials requires extensive knowledge about biological (concerning the cells) and technical (concerning the biomaterial) basics. New questions regarding cell differentiation, cell migration, metabolism and material stability, thus regarding the mutual interactions arise after combining cells and biomaterials. Such a combination was investigated exemplarily in the work in hand. The following questions and goals were formulated in terms of the relevance of mesenchymal stem cells in tissue regeneration in general and the potential application with shape memory polymers in tissue engineering in particular: After an injury, stem cells must receive signals which induce them to leave their niche, circulate in the blood, adhere near the target tissue, migrate into the target tissue, there proliferate and finally differentiate. Can a recruitment factor be identified, which attracts the stem cells out of its niche and conducts the cells to the target tissue At the beginning of the wound healing a thick fibrin mesh is formed, which represents a natural barrier as prevention of infections. Do mesenchymal stem cells have fibrinolytic capacities which would facilitate migration of the stem cells into the wounded area Do mesenchymal stem cells keep their multipotency if they are combined with biocompatible shape memory polymers or does it come to a spontaneous differentiation It can be observed that there is a minor rejection of transplants if mesenchymal stem cells are co-transplanted. What causes the immunmodulatory effects of mesenchymal stem cells These questions could be answered in most instances in the submitted work after sufficient characterization of the isolated cells. The hepatocyte growth factor could be identified as a chemotactic factor for hMSC. The hMSC migrated to HGF in vitro (dependent on the HGF concentration), while the proliferation was suppressed. Human mesenchymal stem cells expressed the fibrinolytic enzymes tPA, uPA and uPAR. Therefore, the arising fibrin mesh during the wound healing does not represent an invincible barrier for the stem cells. The three tested shape memory polymers were cytocompatible for hMSC and did not have any negative influence on the differentiation into osteoblasts and adipocytes. Human mesenchymal stem cells expressed TLR4 and a stimulation with LPS leaded to an enhanced TNF-Alpha expression. The results of this work support the assumption, that mesenchymal stem cells are involved in tissue regeneration. Aachen, Techn. Hochsch., Diss., 2004 ; PUB:(DE-HGF)11, ; 2, ; Dissertation / PhD Thesis 2005 RWTH-CONV-114141 2005 https://publications.rwth-aachen.de/record/51892