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THURSDAY, July 24, 2003 (HealthDayNews) -- For the first time, researchers have found that transplanted brain stem cells aren't rejected by the new body's immune system.
The study in the July issue of Stem Cells found brain stem cells are "immune-privileged." That means they're invisible to a transplant recipient's immune system and don't trigger the immune system to reject them.
The findings indicate that using central nervous system stem cells in transplants for eye, brain and spinal cord diseases may eliminate the need for tissue typing before and immunosuppressive drugs after transplantation.
That holds potential promise in improving the success of a number of transplant procedures such as retinal transplantation to regenerate vision for millions of people with macular degeneration, retinitis pigmentosa and diabetic retinopathy, as well as transplants to restore functioning for people with brain disorders such as Parkinson's disease.
"These findings are very exciting. Though we suspected brain stem cells might be protected in this way, this is the first documented evidence," study author Michael Young, assistant scientist at Schepens Eye Research Institute and assistant professor at Harvard Medical School, says in a news release.
In previous research, Young found brain and retinal stem cells transplanted into the eyes of rats and mice seemed to survive longer and integrate more easily into damaged retinas than other cells. That led him to suspect these stem cells may be immune-privileged.
He and his colleagues confirmed that in this new study by transplanting these neural stem cells into the kidney capsule of mice. The kidney capsule, the pouch in which the kidney is located, always rejects transplanted tissue without immunosuppressant drugs and without close tissue-typing.
After four weeks, the researchers found the stem cells had not been rejected in any of the mice and had actually grown into neural tissue.
"Understanding the immune properties of these stem cells could have an enormous effect on how we perform brain or retinal transplantations in the future. Stem cells already have the advantage of being able to transform or differentiate into various types of cells and can be reproduced endlessly outside the body," Young says.
"Now we know that at least brain stem cells are immune-privileged and can be used without the same worry about tissue matching or immunosuppression that is true for other types of tissue," he adds.
More information
Here's where you can learn more about stem cells.
