Progenitor cells from the adipose tissue: Cell source for the construction of novel in vitro test systems?

Background: Tissue engineering is based on the idea of cultivating cells on suitable matrices. Thereby tissues can be constructed which allows the analysis of different applications under in vitro conditions. Essential for their generation are vital and functional cells like primary cells, but they are often not available in an adequate amount. Therefore stem cells are used, which can be differentiated towards several cell types. Progenitor cells (PCs) from adipose tissue are a possible source. The advantages of these cells are: high availability, extraction by a biopsy, human/autologous material. Methods: The isolation of porcine and human PCs was performed by the treatment of adipose tissue with collagenase, washing steps and a density gradient centrifugation. The characterization of the cells occurred by antibody staining (factor XIII, collagenase IV, tropomyosine). The osteogene and adipogene differentiation succeeded by the treatment with special cultivation media. Results: We have isolated adipose tissue PCs and differentiated them in adipocytes and osteoblasts. The definite differentiation towards two different cell types proves the pluripotence of this cell type. In the adipose tissue the PCs are arranged around blood vessels. The antibody stain against endothelial cells did not succeed in vitro, which proved, that the isolated PCs are in vivo ""adipose tissue pericytes"". Perspective: The long-term aim is to build up a three-dimensional test system with these cells. Ideally it should be a vascularized test system to be able to calculate risks in an overarching way. Such a vascularised test system regarding the liver was developed at Fraunhofer IGB.