Courtesy of Ren-He Xu, Ruthann Perk, Bob Becker
Human embryonic stem cells cultured without mouse feeder cells for 10 months and stained for stem cell markers.
To encourage human embryonic stem cells (hESCs) to multiply without differentiating, scientists currently use a complex chemical mixture provided by mouse embryonic fibroblast "feeder cells." But these nonhuman cells pose problems for therapeutic hESC use. Now a group of researchers has shown how to avoid the mouse products by incorporating basic fibroblast growth factor (bFGF) and noggin, an inhibitor of bone morphogenic protein (BMP), into the growth medium.
Ren-He Xu, of the WiCell Research Institute in Madison, Wis., and colleagues showed that even after 32 passages of dilution in a culture medium containing noggin and bFGF, hESCs remained undifferentiated without the use of a feeder-cell layer. Upon treatment with BMP in the absence of noggin, the cultured cells were able to differentiate into...