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Testosterone Loss Linked to Alzheimer’s

12/21/06
USC study shows hormone therapy slows progression of the disease in mice, a discovery that may be useful for its prevention in men.
By Orli Belman and Athan Bezaitis
“The next step is to look at what the long-term effects of testosterone therapy are in aging men,” said senior author Christopher Pike.

Researchers at USC have discovered a direct link between the loss of testosterone and the development of an Alzheimer’s-like disease in mice. Testosterone treatment, they found, slows progression of the disease.

The study, published in the Dec. 20 issue of The Journal of Neuroscience, predicts that testosterone-based hormone therapy may be useful in the treatment and prevention of Alzheimer’s disease in aging men.

“We’ve known that low testosterone is a risk factor for Alzheimer’s disease, but now we know why,” said Christian Pike, senior author and associate professor at the USC Leonard Davis School of Gerontology. “The implication for humans is that testosterone therapy might one day be able to block the development of the disease.”

In order to investigate testosterone’s role in the development of Alzheimer’s disease, the team took away the ability of male mice to produce testosterone. Some mice then were given a form of testosterone while others were given none.

The mice with lowered testosterone showed increases in levels of the protein B-amyloid (AB), which has been widely implicated as playing a role in the development of Alzheimer’s disease. They also showed signs of behavioral impairment.

The mice that were given testosterone showed reduced accumulation of AB and less behavioral impairment.

“These results are exciting because they tell us that we are on to something that is worth pursuing,” Pike said. “The next step is to look at what the long-term effects of testosterone therapy are in aging men.”

This study adds valuable new information to understanding the role of hormones in aging and disease. Recent evidence has suggested that testosterone may be useful in other neurological conditions. In a recent presentation at the Society of Neuroscience’s annual meeting, Chien-Ping Ko, professor of biological sciences at USC, reported that testosterone therapy improved muscle coordination in mice suffering from a form of Amyotrophic Lateral Sclerosis, or Lou Gehrig’s Disease.

Pike’s co-authors on the Journal of Neuroscience study were Emily R. Rosario and Jenna Carroll of the USC Neuroscience Graduate Program and Salvatore Oddo and Frank M. LaFerla of UC Irvine. The Alzheimer’s Association and the National Institutes of Health provided funding.