Embryonic Stem Cell Lines Derived From Human Blastocysts

November 1998- Two separate groups report their success growing human stem cells in culture.

Dr. James Thomson (University of Wisconsin, Madison) reports derivation of human embryonic stem cells. He used cells derived from human embryos created in vitro, while Dr. John Gearhart (Johns Hopkins University) used stem cells from aborted fetal tissue. The two scientists placed these cells into a mouse cell feeder layer so that the culture would continue to grow indefinitely. The resulting cel lines "produce the enzyme telomerase, which resets the cells' chromosomal clocks" preventing an early death and allowing them to be cultured indefinitely ("The Stem Cell Debate"). Dr. Timothy Kamp generated a difficult to obtain cell type when he differentiates human ES cells into human cardiomyocytes (“Induced Pluripotent Stem (iPS) Cells”).