Thursday July 26 6:01 PM ET
By Amy Norton
NEW YORK (Reuters Health) - With the promise of stem cell research the subject of much recent debate, scientists have new evidence that the primitive cells may indeed help treat defects in the brain--at least those that occur early in brain development.
In experiments in which human brain stem cells were injected into fetal monkey brains, researchers found that the injected cells segregated themselves, with some developing into more mature brain cells and others being put aside--into what the scientists speculate are "pools" of stem cells that the brain can use for later repairs.
"We found the stem cells we put in behaved in an orderly way...like real stem cells," study co-author Dr. Curt R. Freed of the University of Colorado Health Sciences Center in Denver told Reuters Health.
He said the findings suggest that the same could occur if stem cells were introduced to the human brain. According to Freed, this raises the possibility of using stem cells to treat problems of early brain development while a fetus is still in utero. He cited Tay-Sachs, a fatal genetic disease of the central nervous system, as an example--although he stressed there is no evidence that stem cells can treat the disease.
Freed and his colleagues report their findings in the July 26th issue of Sciencexpress, the online edition of the journal Science.
Stem cells are the primitive cells that give rise to a range of body tissue. Because of the potential to mature into a variety of other cells, they are believed to hold promise in the treatment of degenerative diseases--including disorders of the brain such as Alzheimer's. Freed added, it is unclear what the current findings could mean for the treatment of such diseases.
Because stem cells are can be derived from human embryos and aborted fetuses, their use in research has garnered strong opposition. In the new study, researchers used cultured cells originally derived from a human fetus.
In the study, the investigators charted the course of the human brain stem cells after they were injected into the brains of monkey fetuses. They found that the cells separated into two basic populations: one in which the stem cells formed mature brain cells called neurons and glial cells; and one in which the stem cells clustered into various pools and remained in immature form.
The scientists speculate that the fetal brains socked away this second group of stem cells to be used, possibly, for "lifelong self-repair."
The study's authors note that in rodents, brain stem cells have been shown to be "well-suited" for transplants to replace diseased cells.
"Our results suggest that this approach may similarly be feasible in large primates and possibly humans," they conclude.
SOURCE: Sciencexpress 2001;10.1126.