Characterization and culture of human embryonic stem cells

Human embryonic stem (ES) cells are cultured cell lines derived from the inner cell mass of the blastocyst that can be grown indefinitely in their undifferentiated state, yet also are capable of differentiating into all cells of the adult body as well as extraembryonic tissue. Detailed investigation of the properties of embryonal carcinoma cells of both the mouse and human as well as mouse and primate ES cells led to the initial isolation and subsequent culture of human ES cells. The methodologies that were developed to culture and characterize these cell lines have provided a template for the development of human ES cells. The existing data illustrate a number of important differences and similarities between human ES cells and the other cell lines. This review aims to provide a brief historic account of the development of the mammalian pluripotent stem cell field; describe how this led to the isolation, culture, and characterization of human ES cells; and discuss the potential implications of recent advances.