October 25, 1999
Scientists Transplant 'Improved' Brain Cells
WASHINGTON (Reuters) - Scientists said Monday they had transplanted
brain cells from pigs into monkeys using a new process that made the
neurons hold up longer under attack from the monkeys' immune systems.
The idea is to come up with ways to treat PARKINSON'S and other diseases
involving the destruction of brain cells.
The team, from Harvard Medical School and Connecticut-based Alexion
Pharmaceuticals, Inc., said they had protected the pig cells from attack
by the immune system using a product being developed by Alexion.
Dr. Ole Isacson and colleagues at Harvard's McLean Hospital told a
meeting of the Society for Neuroscience in Miami that the transplanted
brain cells survived and functioned.
``To my knowledge, this study represents the first successful
engraftment of pig neurons into primates,'' Isacson said in a statement.
Parkinson's is caused when certain brain cells, which produce a
chemical, dopamine -- important for movement and muscle control -- start
dying off. A few Parkinson's patients have had brain cells from embryos
injected into their brains in the hope of correcting the problem.
But such cells are rare and the practice is controversial. Some
scientists hope to use animal brain cells instead, but the body can
recognize these as foreign cells and reject them.
The researchers used an Alexion product called C5 Complement Inhibitor.
A monoclonal antibody, it is a genetically engineered human protein
currently being tested in human patients in Phase II clinical trials for
the treatment of various chronic inflammatory disorders.
Alexion first genetically engineered pigs to grow brain cells that lack
a certain sugar on the surface and thus do not look quite so foreign to
the human or primate body.
Then they took the dopamine-producing cells from the pigs and further
genetically engineered them to express human complement inhibitor
proteins -- which further protected them from immune attack.
These cells worked to restore brain function in monkeys made to develop
Parkinson's symptoms. Adding the C5 inhibitor made the cells last even
longer, they said.
``We are now focusing on optimizing manufacturing and beginning to
explore the process of initiating human clinical trials,'' Dr. Leonard
Bell, president and chief executive officer of Alexion, said in a
statement.
Copyright © 1996-1999 Reuters Limited.
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Judith Richards, London, Ontario, Canada
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