LOS ANGELES, Dec. 20 (UPI) -- Stem cells taken from adult bone marrow show potential to develop into several types of central nervous system cells, a finding that could lead to treatments for numerous degenerative diseases, a new study released Friday suggests.
Scientists at Cedars-Sinai Medical Center in Los Angeles tested the possible benefits to using stem cells extracted from adult bone marrow in rats. They used modified viruses to transport the bone marrow stem cells into the arteries of rats with ischemic brain lesions, which can occur when blood is choked off from the brain.
As reported in the cover story in the December issue of Experimental Neurology, the stem cells were able to differentiate into three different types of brain cells called astrocytes, neurons and ologodendroglia. They also tracked down brain tissue that had been damaged because of interrupted blood flow, the type of damage caused by ischemic stroke. Forty-eight hours after the stem cells had been injected into the rats, researchers found the transplanted cells already had distributed themselves throughout the brain. This is a critical finding, they said, because it shows the stem cells were able to penetrate the brain's defenses in keeping out toxic or foreign substances.
"A very interesting characteristic of the stem cell is that it seems to be attracted to areas of problems in the brain and these are very different types of problems from stroke to brain tumors," lead researcher Dr. John S. Yu told United Press International.
Yu, who is co-director of the Comprehensive Brain Tumor Program at the Neurological Institute at Cedars-Sinai, said the finding could have implications in treating a host of brain diseases, including stroke, Alzheimer's disease, brain cancer and Parkinson's disease. "I think the door is wide open on being able to start treating these diseases with very specific cellular therapies," he said.
One advantage, Yu noted, is the stem cells would come from the patient's own body. If tested in humans, stem cells taken from a patient's bone marrow could reduce the risk of transplant rejection, which often is seen when transplanted cells from another donor are attacked by the immune system of the recipient.
Adult bone marrow could serve as an untapped reservoir of stem cells, Yu explained. As such, they could eliminate any ethical considerations, such as those surrounding the use of stem cells from human embryos.
Obtaining stem cells from fetal tissue has become a divisive issue in the United States, with many scientists arguing embryonic stem cells offer the most promise in treating several debilitating, chronic illnesses, while critics charge it is immoral to use the unborn for scientific research.
"So our study using stem cells from bone marrow answers both the ethical questions of using stem cells and the immunological questions," Yu said. "These are a very viable means of answering the ethical dilemma that's posed by embryonic stem cells and fetal stem cells."
The findings do not rule out the need to continue embryonic stem cell research, however, Yu added. "I think a lot of studies need to be done both on embryonic stem cells and these stem cells from other organs to determine whether they'll be sufficient to replenish or to be used as stem cells in the brain."
Scientists have questioned whether stem cells from mature tissue could offer the same potential as stem cells from immature or embryonic tissue.
"Adult bone marrow cells are important," Dr. Nelson Chao, a hematologist and director of the bone marrow transplant program at Duke University in Durham, N.C., told UPI. "But I don't think we know whether they can replace embryonic stem cells at this, if they have the same capacity."
Nevertheless, Chao called the study "exciting," adding now that scientists have found they can get the cells to the areas in need, the next step is to determine whether the cells will work properly.
"It's a start," Chao said. "I think we've got a long way to go before we understand which cells to use and when to put them in. I think the ultimate truth will be how will these cells function."
The research was funded by the National Institutes of Health.
(Reported by Katrina Woznicki, UPI Science News, in Washington)
