ABSTRACT
Stem cells are dened by their ability to maintain long-term proliferation and self-renewal. Under specic conditions, stem cells also can differentiate into a diverse population of functionally specialized cell types. There are two main types of human stem cells classied according to their source and developmental potential: embryonic and adult, or tissue-specic, stem cells. Human
CONTENTS
22.1 Introduction ................................................................................................455 22.2 Derivation of Human Embryonic Stem Cells ........................................456 22.3 Dening Properties of Pluripotent Human Embryonic Stem Cells ..... 457
22.3.1 Cell Morphology ............................................................................ 457 22.3.2 mRNA and microRNA Expression .............................................458 22.3.3 Epigenetic Characteristics ............................................................ 459 22.3.4 Pluripotency In Vitro and In Vivo ............................................... 459
22.4 hESC-Derived Progenitors and Their Use in Cell-Based Therapies ..... 461 22.4.1 Ectodermal Derivatives ................................................................. 461 22.4.2 Endodermal Derivatives ...............................................................463 22.4.3 Mesodermal Derivatives ...............................................................464
