X-Message-Number: 12824
Date: Tue, 23 Nov 1999 16:53:17 -0500
From: Jan Coetzee <>
Subject: Decade-old transplant survives

Decade-old transplant survives in Parkinson's patient

NEW YORK, Nov 22 (Reuters Health) -- A decade after human embryonic
brain cells were
transplanted into the brain of a 69-year-old man with Parkinson's
disease, the cells still survive
and are releasing dopamine, a brain chemical, researchers report.

``This is the first report to demonstrate... that grafts of fetal human
midbrain tissue not only store
dopamine but can release it in a (normal) manner,'' and continue to
relieve Parkinson's disease
symptoms, Dr. Paola Piccini of the Imperial College School of Medicine
in London, UK, told
Reuters Health.

Parkinson's disease is a brain disorder characterized by slowness of
movement, rigidity, and
tremors. A type of brain cell, the neuron that produces dopamine, is
lost in an area of the brain
called the basal ganglia, which controls voluntary movements. Drugs that
replace dopamine can
be used to treat the disease, but they eventually fail and also produce
debilitating side effects.

In the December issue of Nature Neuroscience, Piccini and colleagues in
the UK and Sweden
describe how they used an imaging technique to measure dopamine release
from the transplanted
neurons.

The Parkinson's patient who was studied had responded well to the
transplanted cells that were
implanted only into the right side of the brain. Therefore, the
researchers were able to compare
the function of the transplanted and nontransplanted sides of the brain.
Five healthy people were
studied for comparison.

The investigators found that the ability of the patient's brain cells to
store dopamine on the
transplanted side of the brain was restored to the same levels observed
in the healthy volunteers.
In contrast, the nontransplanted side stored dopamine at only 12% of
normal levels.

Piccini's group also found evidence that the transplanted neurons were
releasing dopamine. Peak
dopamine levels were increased by 2- to 10-fold, according to the
report.

There were no signs of transplant rejection, even though the patient had
not received any immune
system therapy for over 4 years.

``Our intention is now to explore other sources of (dopamine-releasing)
tissue,'' Piccini said in
the interview with Reuters Health. ``Success in this area should make
transplantation available to
a far wider population of Parkinson's disease patients.''

SOURCE: Nature Neuroscience 1999;2:1137-1140.

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