Parkinson research: (Courtesy of The Yomiuri Shimbun)
Japanese researchers have
been able to improve the symptoms of Parkinson's disease in monkeys by
transplanting nerve cells derived from embryonic stem cells into their brains,
the team has announced.
The finding is the world's first
reported success of its kind with a primate, according to the research team led
by associate professor Jun Takahashi of Kyoto University's Institute for
Frontier Medical Sciences. It has been released in the online edition of US journal Stem
Cells.
After the transplant, the monkeys,
which had been almost unable to move, showed improvements in their symptoms to
the point where they became able to walk on their own, the team said.
Parkinson's disease is a
neurological illness believed to be caused by a deficit of the neurotransmitter
dopamine in the brain.
Embryonic stem cells, which have the
potential to become almost any type of tissue, are harvested from inside a
blastocyst, which develops from a mammalian egg cell about a week after it is
fertilised.
Takahashi's research team used the
embryonic stem cells to cultivate a cell mass in which 35 per cent of the cells
were dopamine-producing neurons.
These neurons then were transplanted
into the four crab-eating monkeys, whose conditions were observed over a
one-year period.
According to the study, the monkeys
exhibited reduced shaking of their limbs half a year later. They had remained
nearly motionless inside their cages all day long before the transplant, but
the improvement of their symptoms eventually enabled them to occasionally walk
around the cages.
The research team confirmed that
normal nerve cells had been created in their brains.
The finding could mark a major
breakthrough for applying embryonic stem cells in clinical settings, experts
said. The Health, Labour and Welfare Ministry has been encouraging researchers
to study the clinical applications of not only stem cells, but also induced
pluripotent stem cells, which also can grow into many kinds of human cells.
Takahashi's team has already
performed experiments to transplant iPS cells into monkeys' brains.
"We'll make further efforts to
enhance the safety of these cell transplants," Takahashi said. "And
we hope to start clinical application studies as early as three years from now."
