Researchers have discovered a new source of neural stem cells in the adult brain. The discovery is reported in Nature (19 February 2004, Vol. 427, No. 6976, pp. 740-744).
Arturo Alvarez-Buylla and colleagues studied brain tissue samples taken from live patients undergoing brain surgery and from post-mortem brain donors. Cells taken from the lining of the lateral ventricle - a fluid-filled cavity inside the brain - appeared to be stem-cell-like in culture. They divided to form new stem cells and were able to generate different, mature types of brain cell.
In the human brain, the stem cells form a ribbon-like structure. Their organization is unique - similar structures have not been seen in any of the animal species tested so far, including primates. The cells are also unusual because they don't migrate. Stem cells from analogous regions in the rodent brain travel from their birthplace to the olfactory bulb - a brain region that processes smells - where they generate thousands of new neurons every day. Our lack of stem cell migration might explain our comparatively poor sense of smell.
So what do these stem cells do? Their function is unclear, but in an accompanying News and Views article, Pasko Rakic suggests that they could divide uncontrollably to form brain tumours. But they could also be a good thing. They might divide to form replacement brain cells. To fully harness stem cell potential for regenerative medicine, researchers will have to decipher the signals that control stem cell fate and stem cell migration, he says.
University of California
San Francisco, CA
Tel: +1 415 514 2348
Pasko Rakic Yale University School of Medicine
New Haven, CT
Tel: +1 203 785 4330
(C) Nature press release.
Message posted by: Trevor M. D'Souza