(UPDATED: See below.)

blastocyst.jpgStem-cell proponents have long told anyone who will listen that U.S. restrictions on the research will lead to a “brain drain” of scientists emigrating to other countries where the work can proceed without limits.

The prospect of the brain drain, though, was always somewhat overblown, as only a handful of scientists have emigrated specifically to escape federal limits on stem-cell research. Among them were Roger Pedersen, the UCSF biologist who in 2001 decamped to the University of Cambridge in the U.K. and two husband-and-wife scientists — Neal Copeland and Nancy Jenkins of the NIH and Edward Holmes and Judith Swain of UCSD — who left for Singapore last year. (Holmes’ decision to move is especially hard to paint as a “brain drain,” since he sat on the powerful committee that oversees California’s $3 billion stem-cell program.)

These days, it’s equally tempting to suggest that the brain drain — to the extent that it ever existed — has been reversed into a “brain gain.” Several California universities have boosted their hiring of stem-cell researchers and administrators from elsewhere in the U.S., and now some foreign scientists seem willing to pull up roots for the Golden State as well.

shinya-yamanaka.jpgYesterday, for instance, the Gladstone Institute of Cardiovascular Disease, a research organization affiliated with UCSF, announced that it had hired Shinya Yamanaka, a Japanese researcher who recently demonstrated a way to revert ordinary skin cells back into a stem-cell like state. (See our coverage here (first item); Yamanaka is pictured to the left.) It’s a homecoming of sorts for Yamanaka, a Kobe University researcher who was a postdoc and then a staff research investigator at Gladstone in the mid-1990s. Arlene Chiu, interim chief scientific officer for the California stem-cell program, called the move “a great coup for Gladstone and for California.” Gladstone, apparently hoping to maximize the publicity effect, has already put up a bio page for Yamanaka.

The move is certainly a coup for California’s still-nascent stem-cell effort, especially since as recently as two months ago, Yamanaka had disavowed any desire to leave his native Japan. As a harbinger of a reverse brain drain, however, it’s still pretty weak beer. That’s particularly true since Yamanaka is only going to be spending one week a month in San Francisco for the next year or two, according to the WSJ health blog, although the institute’s head said he hopes to bring the Japanese scientist on full-time in two years.

For more background on Yamanaka, try this WSJ column by Peter Landers.

UPDATE: David Jensen over at the California Stem Cell Report runs with a list of the nearly 50 stem-cell researchers who have come to California since the state’s stem-cell program was approved by voters. Two caveats: The list was produced by the stem-cell agency itself, and it doesn’t include names of scientists who have moved out of the state, so it’s a fairly one-sided perspective on the question. Still, it’s worth a look if this sort of thing interests you.