MONDAY, May 14 (HealthDay News) -- Testosterone gel may slow the progression of multiple sclerosis in men with the disease, a new study suggests.
Only 10 men took part in the research, all had milder forms of MS, and more studies will be needed before doctors determine whether the treatment really works. Still, the researchers were impressed that the men's mental decline ceased, and the shrinking of their brains returned to the normal levels expected due to aging.
"We saw an improvement which was exciting," said study co-author Dr. Rhonda Voskuhl, professor of neurology at the University of California, Los Angeles. "This looks like it would be neuroprotective, which would be great."
But another expert, Dr. Moses Rodriguez, professor of neurology and immunology at the Mayo Clinic, said he was skeptical that the treatment would become common and noted that MS research has had a history of promising therapies that ultimately failed.
A treatment that protects the central nervous system against multiple sclerosis would be a major breakthrough for the 400,000 Americans with the disease. MS is thought to be caused when the immune system attacks the myelin sheath, a fatty substance that insulates nerves in the brain and spinal cord. It can cause a wide range of symptoms, from cognitive decline and pain to severe fatigue and difficulty walking. Most people with the disease have normal or near-normal life spans.
Women are two to three times more likely to get the disease, and there has been speculation that testosterone -- the male hormone -- could protect men against MS.
While injection drugs can slow the progress of the disease, researchers have been trying to find a way to boost their effectiveness.
In the new study, the researchers followed 10 men with mild MS who, for a variety of reasons, chose not to take injection treatments. The average age of the participants was 46. After the researchers monitored the men's conditions for six months, each man applied 10 grams of a gel containing 100 milligrams of testosterone to his upper arms once daily for 12 months.
"The cognition improved instead of declining," Voskuhl said. "We were pretty surprised by seeing an improvement." The study authors also found that the rate of brain atrophy declined by two-thirds, to the rate expected during normal aging. In another promising sign, the men ended up with more muscle mass after undergoing the treatment.
Unfortunately, testosterone treatment would not be feasible in women because of its side effects, Voskuhl said. But researchers are looking into other possible treatments for women.
Voskuhl also thinks that testosterone treatment -- if it turns out to work in other studies -- could lead to better therapies for diseases such as Alzheimer's and Parkinson's.
The findings are published in the May issue of the Archives of Neurology.
But the Mayo Clinic's Rodriguez, who's familiar with the study findings, said he doubts that testosterone therapy will become standard, because it has side effects and has been connected to an increased risk of prostate cancer. Also, much promising but preliminary MS research fails to bear fruit, he said.
Voskuhl said further research will take three to five years, largely because it takes time to get funding. Doctors could legally give testosterone to MS patients now, but she said it's not approved for that purpose.
"You really should wait until the larger trials are finished and we go for FDA (U.S. Food and Drug Administration) approval," Voskuhl said.
However, Rodriguez believes MS patients would be taking a "great risk" if they underwent testosterone treatment before it was federally approved for that purpose.
Learn more about MS from the National Multiple Sclerosis Society.
SOURCES: Rhonda Voskuhl, M.D., professor of neurology, University of California, Los Angeles; Moses Rodriguez, M.D., professor of neurology and immunology, Mayo Clinic, Rochester, Minn.; May 2007, Archives of Neurology