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| Diagram of a human thymus gland--Courtesy of the National Cancer Institute |
Scottish scientists report that they have successfully regenerated a living mouse organ and transplanted it into a young mouse.
The investigators, from the University of Edinburgh, rebuilt an important immune organ called the thymus in aged mice by reactivating a certain protein produced in the thymus--called FOXN1--which helps to control how certain important genes are switched on. By increasing production of FOXN1, the team was able to instruct stem cell-like cells to rebuild the organ in older mice. The findings are detailed in the journal Development.
"Our results suggest that targeting the same pathway in humans may improve thymus function and therefore boost immunity in elderly patients, or those with a suppressed immune system," said Clare Blackburn, professor of tissue stem cell biology at the University of Edinburgh's MRC Centre for Regenerative Medicine, in a statement.
Located next to the heart, the thymus plays a central role in the immune system by producing T cells needed to attack foreign invaders. The gland is bigger in children and deteriorates with age, which is why older people are often more susceptible to infections such as flu. In certain congenital and autoimmune problems, the thymus malfunctions and compromises the body's ability to fight off infection.
The advance could lead to new therapies to help treat people with genetic conditions that affect thymus development, such as DiGeorge syndrome, as well as those with damaged immune systems.
By essentially restarting FOXN1, a natural mechanism that shuts down with age, the researchers were able to rejuvenate the thymus in genetically modified elderly mice. After treatment, the regenerated organ resembled on found in a young mouse.
The investigators observed that in older mice with the revived thymus, T cells produced increased, but it's not yet clear whether the treatment improved the mice's immune system.
- see the press release
- read the study