Washington D.C. - Research by a group of Italian and Canadian scientists indicates that certain adult cells-previously assumed to be permanently wedded to their specialized roles in the body-can shed their identities and reinvent themselves as different types of cells. In the study, reported in the 22 January issue of Science, the authors transplanted adult stem cells from the brains of adult mice into the bone marrow of new mice, where the stem cells changed their behavior and began generating blood cells. The findings raise the possibility that in the future adult stem cells could be used to supply a variety of new cells for important therapeutic uses, for example to generate healthy blood cells for treating patients with blood disorders.
Researchers recently proposed that using stem cells to grow healthy tissues was one of several beneficial applications for their new-found ability to grow human stem cells from early-stage embryos, a finding announced in Science last November. Embryonic stem cells are primordial cells that divide indefinitely and give rise to the body's different cell types as they develop. However, although these cells may have the potential to provide considerable benefits, they also pose some controversial ethical implications because they come from human embryos.
Now, a study on mice by Angelo Vescovi, of NeuroSpheres Limited in Canada and the National Neurological Institute in Italy, and his colleagues suggests that stem cells don't have to come from embryos in order to generate specialized cells. "We went the other way around and used adult stem cells instead," said Vescovi.
Adult stem cells are more specialized than the primitive stem cells of an early
embryo. These stem cells supply new cells to parts of the body with a high
cellular turnover rate, such as the hematopoeitic (blood producing) system, the
intestines, or the skin. In their experiment, Vescovi and his colleagues used
neural stem cells (N
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American Association for the Advancement of Science