A man in
his mid-50s with Parkinson's disease had fetal brain cells injected into his
brain last week. He is the first person in nearly 20 years to be treated this way
– and could recover full control of his movements in roughly five
years.
"It
seemed to go fine," says Roger Barker
of the University of Cambridge, who is leading the international team that is
reviving the procedure.
The
treatment was pioneered 28 years ago
in Sweden, but two trials in the US
reported no significant benefit within the first two years following the
injections, and the procedure was abandoned in favour of deep brain stimulation
treatments.
What these
trials overlooked is that it takes several years for fetal cells to "bed
in" and connect properly to the recipient's brain. Many Swedish and North
American recipients improved dramatically, around three years or more after the
implants – long after the trials had finished. "In the best cases,
patients who had the treatment pretty much went back to normal," says
Barker
After the
fetal cells were wired up properly in their brains, they started producing the
brain signalling chemical dopamine – low levels of this cause the classic
Parkinson's symptom of uncontrolled movements. In fact, the cells produced so
much dopamine that many patients could stop taking their Parkinson's drugs.
"The prospect of not having to take medications for Parkinson's is
fantastic," says James Beck of the Parkinson's Disease Foundation in the
US.
Because
the early trials missed this improvement no one had received fetal brain cells
since the 1990s. But the man treated at Addenbrooke's Hospital in Cambridge on
18 May did not receive a full treatment, because the team only had enough cells
to treat one half of his brain.
The
transplant depends on fetal cell donations from women terminating pregnancies,
so the researchers don't know when cells are likely to be available. It takes
cells from at least three fetuses to treat each half of the brain, and four
earlier attempts to treat the same man had to be stopped due to a lack of
cells.
Lack of cells
But
Barker hopes to treat the other half of the man's brain soon. "We would
expect that if we do both sides, he will see an improvement in around six
months to a year," says Barker. But the maximum benefits are predicted to
happen in three to five years' time, and should then be sustained for more than
a decade, he says.
The team
plans to test the treatment in a further 19 people, in a trial split between
Cambridge and Sweden.
Barker
sees the revival of the technique as a stepping stone to injecting
dopamine-producing cells made by stem cells (see "Stem cells – the next
step" below). Trials of such treatments are expected as early as 2017, and
Barker hopes lessons learned from the fetal cell transplants will guide how to
apply and assess them once they are ready.
"We
are now on the road towards a 2.0 version of the cell therapy paradigm,"
says Lorenz Studer
of the Memorial Sloan Kettering Cancer Center in New York. He thinks future
treatment will eventually involve the use of dopamine neurons that come from
stem cells rather than fetal cells, which will permanently resolve the supply
problem.
Members
of the Parkinson's Disease Global Force met
in New York last week to discuss the progress of this stem cell work. When
Barker announced that his team's first patient had just left the operating
theatre, the meeting's attendees burst into spontaneous applause.
"There's
a real sense within the community that this is a collaborative effort to make
cell treatments work, and that there's real potential to change the lives of
hundreds of people worldwide," said Barker.
Stem
cells – the next step
The team
behind the fetal cell treatment (main story) hopes it will pave the way for
bespoke stem cell treatments to replace the missing dopamine in people with
Parkinson's disease. Rather than relying on fetal cells, these stem cell
treatments could in theory be made to order.
Four
teams – two in Europe and two in the US – have managed to make neurons from
embryonic stem cells and all are hoping to use them to treat people
with Parkinson's. Unlike fetal cells, these stem cells can provide a limitless
supply of neurons because they can divide many times.
Meanwhile
in Japan, researchers are using "induced pluripotent" stem cells to
make dopamine-producing cells. Unlike embryonic stem cells, such iPS cells can
be created from an adult's ordinary body tissues.
Roger
Barker of the University of Cambridge says all these teams are now gearing up
to test their cells in patients, hoping to begin in 2017.
http://www.newscientist.com/article/dn27593-fetal-cells-injected-into-a-mans-brain-to-cure-his-parkinsons.html?cmpid=RSS%7CNSNS%7C2012-GLOBAL%7Conline-news#.VWXoEGCKzAM
No comments:
Post a Comment