University of Wisconsin researchers successfully introduced human stem cells into rats afflicted with Lou Gehrig’s Disease using a method that could one day be applied for treatment in humans.

The researchers took genetically modified human stem cells and inserted them into the spinal cord of rats infected with the disease, discovering that the stem cells survived and also produced an important protein that preserves the motor neurons that often die in neurodegenerative diseases.

Results of the findings appeared in the journal Human Gene Therapy Tuesday.

Lou Gehrig’s Disease, or amyotrophic lateral sclerosis, is a progressive neurodegenerative disease affecting nerves in both the brain and spinal cord. The cause of the disease is not fully understood and there is currently no cure or treatment successfully halting the disease, according to the ALS Association.

“In ALS, motor neurons in the spinal cord die, causing death and paralysis in humans,” said lead author of the study Sandra Klein, a UW physiology graduate student. “We were trying to protect these motor neurons from dying in the first place.”

Rats were used as a model for ALS in humans because the rodents develop the disease in a similar manner, Klein said.

To stop the motor neurons from dying, researchers first grew genetically engineered progenitor, or specialized, neural stem cells designed to produce the protective protein known as glial cell-line derived neurotrophic factor, according to Klein.

The scientists delivered the stem cells into a specific area of the rat’s central nervous system through a unique technique involving a micropipette. The approach, which Klein developed, tackled an important problem involving the method of stem-cell entry into the animal.

Results showed the human neural stem cells survived transplantation to integrate into the rat spinal cord and also continue to pump the protective GDNF protein.

“Although we didn’t see an overall effect on the animal’s survival of the disease, we did see local affects on motor neuron characteristics,” Klein said.

UW anatomy professor Clive Svendsen, a co-author of the study, was pleased with the results and said though the research is preliminary, the lab will continue studying the disease.

“It’s important that we have shown these human progenitor cells can actually survive in the brain of these ALS rats and can make [essential proteins],” Svendsen said. “We can now at least think about [using this method] in human patients.”

Svendsen stressed that the study is preliminary, and much is unknown about ALS. He added that if the same transplantation procedure is performed in humans, results could be different than in the rats.

“Models are only so good — it is almost impossible to predict what would happen in humans,” Svendsen said.

Klein believes transplantation of the stem cells into people will be successful someday since the cells they are using are human.

Future studies in the lab will involve transplanting the genetically modified stem cells to more regions of the diseased rat, according to Klein. Also, the lab will study whether the progenitor cells can prolong the life of the rat.