Researchers are looking for the right stem cell and the right conditions to grow it to the right differentiation stage. Here, adult stem cells share the limelight with embryonic stem cells (ESCs), and not simply because they enjoy a more favorable political climate. One recent review commented that using cells already heading toward the beta cell pathway might be more productive than starting with totally undifferentiated embryonic cells.3
Taking a different approach, Spanish scientists working with murine ESCs used gene-trapping technology to isolate insulin-producing cells. In this scheme, researchers transfected an antibiotic resistance gene adjoined to an insulin promoter into ESCs, providing a selection for insulin-producing cells.5 When allowed to form three-dimensional structures, the cells subsequently isolated increased insulin production to therapeutic levels.6
Last August, Israeli scientists found insulin-producing cells among human embryoid bodies-the three dimensional structures that ESCs spontaneously form when they stop growing.7 Like the murine stem cells, ...
