Monday April 27 10:39 PM EDT=20

Cloned brain cells may treat Parkinson's

By Maggie Fox, Health and Science Correspondent=20

WASHINGTON (Reuters) - Researchers said Monday they had created a =
possible new source for treating Parkinson's patients -- the brain cells =
of cloned cattle.=20

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.=20

They said they hoped the technique could one day be used in people.=20

The scientists' approach combined three new and controversial =
technologies -- cloning, genetic engineering, and the use of fetal brain =
cells to treat Parkinson's.=20

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.=20

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.=20

Victims have a shortage of dopamine -- an important brain chemical that =
plays a role in muscular movement.=20

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.=20

Aborted or miscarried fetuses have been the source, but using them is =
highly controversial.=20

"A major problem for this emerging therapy is the limited and variable =
supply of human fetal tissue," the researchers wrote in their report.=20

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.=20

"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.=20

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.=20

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.=20

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.=20

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.=20