Human embryonic stem cells (hESCs) hold great therapeutic promise since they are capable
of generating specialized cells that may be utilized to replace damaged tissues in patients suffering from
various types of diseases. However, this application is dependent on a comprehensive understanding of
the signalling mechanisms involved in ESC lineage restriction, an area in which further scientific
proficiency is needed. Moreover, the development of clinical applications using hESCs rests on the
formulation of appropriate culture conditions that would allow for the isolation and maintenance of
homogeneous, genetically and epigenetically stable cell populations. The stability of these cells is
critical to diminish potentially adverse effects following transplantation, such as host rejection, low
survival of the grafted cells and maybe even tumor formation. In this chapter I will describe the current
techniques for isolating, characterizing and maintaining hESCs in culture. I will address some of the
challenges underlying these methods and, when possible, offer alternatives that may help overcome
these challenges. Finally, I will discuss the current limitations that have made hESC-based therapy a
discipline still in its infancy and we will provide my view of where the field of personalized stem cellbased
medicine is likely to go in the future.
Keywords: hESC derivation, hESC characterization, stem cell niche, pluripotency.
