CELLS grown from discarded eye tissue will be used later this year as an
experimental treatment for Parkinson鈥檚 disease.
The neurotransmitter dopamine, which conveys signals to neurons in the brain,
is normally made by cells in a part of the brain called the substantia nigra. In
Parkinson鈥檚, these cells gradually die, and patients lose control of their
movements.
To restore dopamine levels, scientists are developing treatments such as
transplanting dopamine-producing cells from fetuses and from the patient鈥檚 neck
(This Week, 1 May, p 24).
Louis Bucalo of Titan Pharmaceuticals in San Francisco
and his colleagues wondered if eye banks might provide a better source of cells.
Among the eye tissue thrown away after corneas are removed for transplantation
are retinal cells that produce dopamine.
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A team at Titan cultured the cells and attached them to gelatin beads,
producing a substance they call 鈥渟pheramine鈥� that is easy to handle. 鈥淭he
product is intended to be closer to a pharmaceutical than a human tissue
transplant,鈥� says Bucalo. They injected spheramine into the brains of monkeys
with a disease similar to Parkinson鈥檚.
Spheramine was as effective at improving the monkeys鈥� symptoms as standard
drugs, but its effects lasted much longer鈥攂etween six and eight weeks, as
opposed to a few hours. The team will describe their findings at a conference in
Vancouver next month.
The researchers hope the technique will get round practical problems
associated with transplanting fetal cells. Less than 20 per cent of transplanted
fetal tissue survives. But about 80 per cent of transplanted tissue survives in
the spheramine technique, and a single sample of eye tissue could provide enough
spheramine to treat 10 000 patients. Clinical trials of the treatment will start
later this year.