A group of small molecules can spur the growth of stem cells from umbilical cord blood. These could one day be used as transplants to treat, for example, certain blood cancers.

Guy Sauvageau at the University of Montreal in Canada and his colleagues screened a library of small molecules for ones that stimulate the proliferation of human cord-blood stem cells that drive the long-term production of all blood cells. They found one molecule that worked particularly well and synthesized an optimized version, UM171, that performed even better. This molecule triggered the expansion of cord-blood stem cells that, when transplanted into mice, generated the full array of mature blood cells.

Cord-blood stem cells could be an alternative to bone-marrow transplants, which are currently in short supply, the authors say.

Science 345, 1509–1512 (2014)