PD干细胞的突破

New research has paved the way to treating Parkinson's disease with stem cells derived from a patient's own skin.
Scientists "reprogrammed" skin cells from Parkinson's patients and then transformed them into brain neurons. At the same time they were able to remove potentially harmful viruses used in the process.
The viruses ferry genes into the cells that cause them to revert to a stem cell-like state. But if they are allowed to remain they can cause cancer.
Stem cells are immature cells that can take on a variety of specialised roles.
Those obtained from cannibalised human embryos have the greatest potential, but many object to their use on ethical grounds.
Recently scientists learned how to reprogramme normal cells into induced pluripotent stem (iPS) cells which have the same properties as embryonic stem cells. But the technique is hampered by the need to use potentially harmful viruses.
In the new study, reported in the journal Cell, scientists used viruses that could be inserted and then removed.
Research leader Dr Rudolf Jaenisch, from the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, US, said: "We used a modified virus you can excise. After they've done their job, you can get rid of them."
After the cells were reprogrammed they were treated with chemicals to turn them into nerve cells producing dopamine, a signalling molecule that is under active in Parkinson's patients.
"The next step is to use these iPS-derived cells as disease models, and that's a high bar, a real challenge," said Dr Jaenisch. "I think a lot of work has to go into that."