WASHINGTON (Reuters) - Reuters [OL] via
NewsEdge Corporation : Researchers said Monday
they had created a possible new source for treating
Parkinson's patients -- the brain cells of cloned
cattle.

Brain cells from cattle fetuses were genetically
engineered, then cloned and injected into rats with
Parkinson's disease. The treatment seemed to
reduce the symptoms in the rats, the researchers
reported in the journal Nature Medicine.

They said they hoped the technique could one day
be used in people.

The scientists' approach combined three new and
controversial technologies -- cloning, genetic
engineering, and the use of fetal brain cells to treat
Parkinson's.

Dr. Curt Freed at the University of Colorado School
of Medicine, Dr. Steven Stice of the University of
Massachusetts at Amherst and colleagues said
they had been intrigued by reports about brain cell
transplants for Parkinson's patients.

There is no cure for Parkinson's, a common brain
disorder that causes tremors and progresses to
total muscle failure and death. It afflicts 1 percent of
people over the age of 50.

Victims have a shortage of dopamine -- an important
brain chemical that plays a role in muscular
movement.

Research has shown that their dopamine-producing
brain cells have somehow been destroyed. But
some experiments have shown Parkinson's patients
might be helped with injections of these brain cells
from human fetuses.

Aborted or miscarried fetuses have been the source,
but using them is highly controversial.

``A major problem for this emerging therapy is the
limited and variable supply of human fetal tissue,''
the researchers wrote in their report.

Earlier this year Stice's team reported they had
cloned a small herd of cattle using fetal cells -- not
the difficult technique that produced Dolly the
sheep, cloned from an adult cell, but nonetheless a
hard task.

They teamed up with Freed's group to see if such
cloned fetuses might help Parkinson's patients.

``Their study highlights some of the potential
benefits of this technology and will inevitably
rekindle many of the debates about cloning,'' Keith
Campbell of Scotland-based PPL Therapeutics, the
company that cloned Dolly, said in a commentary.

The researchers cloned cattle fetuses, genetically
engineered them, grew them until their brain cells
were at a certain stage, and removed the brain
cells. These brain cells -- neurons that produce
dopamine -- were injected into the brains of rats.

It is hard to tell with rats, but the animals displayed
less ``circling behavior'' -- one of the symptoms of
Parkinson's in rats. The researchers killed some of
the rats and looked at their brains and saw that in
many cases, the injected cells had grafted onto
their brains.

Using genetically engineered clones has two
advantages -- genes can be added to reduce the
risk that the patient's immune system will reject the
cells, and scientists can produce cells that are
exactly alike, with an effect thus more predictable.
The researchers think cattle fetuses could have
human genes added and be used as a source of
brain cells. But this calls for xenotransplantation --
using animal tissues in humans -- which is another
hotly debated area.

Scientists point out the risk of transmitting unknown
diseases, and changing some of the genes does
not always do away with the risk of rejection by the
patient's immune system.