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Therapy extends life in rats with nerve disease
Tue Sep 23, 2008 12:27am BST


[-] Text [+] By Julie Steenhuysen

MADISON, Wisconsin (Reuters) - Treatment with genetically modified stem cells helped rats with a paralyzing disease live significantly longer, U.S. researchers said on Monday in a finding that could one day help humans.

Rats with ALS that were treated with the gene-engineered stem cells lived 28 days longer than untreated mice, the researchers told a conference.

Amyotrophic lateral sclerosis or Lou Gehrig's disease progressively attacks nerve cells called motor neurons, which waste away and die. Rather than trying to replace the motor neurons, the researchers used stem cells as a way of delivering a growth factor to keep them alive.

They injected the rats with adult nerve stem cells that were engineered to release a growth factor called glial cell-line derived neurotrophic factor or GDNF.

"It's a fertilizer for neurons that die in ALS," said Clive Svendsen, a University of Wisconsin-Madison professor of neurology, who led a panel meeting on ALS at the World Stem Cell Summit in Madison.

"It's the first time we've seen functional recovery in this model," Svendsen said in an interview. "They're not cured, but they lived significantly longer than non-treated rats."

Prior studies in rats showed that injecting nerve stem cells with GDNF into the spinal cord helped spare some of the motor neurons, but it did nothing to help the rats live longer.

"We protected the motor neurons in the spinal cord but the rats kept getting paralyzed," Svendsen said.

There is no cure for ALS, which kills gradually by paralyzing patients. About 120,000 new cases are diagnosed each year, according to the International Alliance of ALS.

BROKEN CONNECTION

The researchers suspected this may have been because the motor neurons were unable to reconnect at the muscle, a place called the neuromuscular junction.

Some studies have suggested that this loss of connections where the neuron connects with the muscle may occur early in the disease process. The Wisconsin team wanted to see if they could target the junction and restore the connection.

Svendsen and colleague Masatoshi Suzuki turned to primitive muscle cells called mesenchymal stem cells, which are found in bone marrow. They engineered them to express, or produce, GDNF plus a green fluorescent protein so they could see where the cells went.

Not only did the rats live longer but they regained muscle function and outlived untreated rats, Svendsen's team reported in the Nature journal Molecular Therapy.

Svendsen said his group is now trying to deliver the growth protein using nerve stem cells in the spine and muscle stem cells injected into the neuromuscular junction.

If this works, he said the group plans to seek U.S. Food and Drug Administration approval to start tests in humans.



http://uk.reuters.com/article/scienc...34328720080922