The discovery of an adult stem cell that could differentiate into every cell type has caused a stir within the scientific and non-scientific community.

New Scientist reported how a patent application from a team led by Catherine Verfaille at the University of Minnesota reveals that a class of stem cells, called multipotent adult progenitor cells (MAPCs), could be as versatile as embryonic stem cells (ESCs).

The MAPCs were isolated from bone marrow by enrichment and seem to grow indefinitely in culture (some for almost two years), and show no signs of ageing. Implanting MAPCs from humans and mice into blastocysts has found they share a striking similarity with ESCs. “Given the right conditions, MAPCs can turn into a myriad of tissue types: muscle, cartilage, bone, liver and different types of neurons and brain cells”, (New Scientist, 26 January 2002).

Although Verfaille said it was too early to hail MAPCs as the ultimate stem cell, the finding has been used by opponents of embryo research to show that it makes such research redundant. “'Science continues to prove that destructive embryonic stem cell research is unnecessary,' said Senator Sam Brownback, Republican of Kansas”, (The New York Times, 25 January 2002).

But scientists, including Verfaillie, remain cautious about the findings, as fundamental questions remain unanswered. One is whether MAPCs progress to form functioning cells. The other is whether the MAPCs are reprogrammed back into a semi-embryonic state as a result of the selection process.