Drug May Shield Brain Cells From Huntington's Disease
WEDNESDAY July 25, 2007 -- A drug used in some countries to manage Huntington's disease symptoms is successful in protecting mouse brain cells from early death, new research shows.
The drug, tetrabenazine, "can actually prevent brain cells from dying," study senior author Dr. Ilya Bezprozvanny, associate professor of physiology at University of Texas Southwestern Medical Center at Dallas, said in a prepared statement. "It's much more important than people thought," the researcher said.
Huntington's disease is a genetic disease in which neurons start to degenerate in specific parts of the brain, causing a loss of mobility, mental function and emotional stability. Symptoms usually appear when people are in their 30s or 40s, after cell death has already begun. About one in 10,000 people have the disease, and another 200,000 are at risk. Although there are medications to manage the symptoms, there are no drugs available to slow the progression of the disease.
Bezprozvanny's team tested tetrabenazine on mice that are genetically altered to mimic human Huntington's disease. The drug, which is prescribed in countries outside the United States to manage the disease, is commercially distributed as Xenazine or Nitoman.
The researchers focused on an area of the brain called the striatum, which relays signals concerning motion and higher thought. It is a message center and also receives signals from several other brain regions. Huntington's disease results in the death of many of the neurons in the striatum.
The researchers gave both the normal and the genetically altered mice coordination tests. The Huntington's-like mice were given a drug that increased brain dopamine levels, as well as the tetrabenazine.
Those with increased dopamine performed worse on the tests, while tetrabenazine appeared to protect against the dopamine effect and preserved cells in the striatum.
Writing in the July 25 issue of Neuroscience, Bezprozvanny and colleagues called for further research to determine whether the effect would be the same in humans. However, they cautioned that it is always difficult to test the effectiveness of a drug that is aimed at preventing symptoms before they occur.
For facts about Huntington's disease, visit the Huntington's Disease Society of America.
Posted: July 2007