Culture of human embryonic stem cells and the extracellular matrix microenvironment.

Among the major obstacles impeding successful derivation and continuous culture of human embryonic stem cells (hESC) for therapeutic purposes, are the presence of feeder cells and feeder-conditioned media of animal origin. The risk of contamination with xenopathogens makes hESC cultured in this way unsafe for future use in regenerative medicine. A holy grail for investigators in the field will be to establish and maintain new hESC lines in completely feeder-free and serum-free defined conditions. Recently, propagation of hESC has become possible, using mammalian- or human-derived extracellular matrix (ECM) and conditioned medium from feeder cells. In addition, providing a three-dimensional ECM environment can even support the derivation of new hESC. In this review, we examine recent advances in the use and development of substrates suitable for the derivation and maintenance of hESC, and our current understanding of the effects of a three-dimensional ECM milieu on cellular behavior.