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LOS ANGELES -- Testosterone supplements are safe and well-tolerated in men with relapsing-remitting multiple sclerosis, according to researchers here.
LOS ANGELES, May 14 -- Testosterone supplements are safe and well-tolerated in men with relapsing-remitting multiple sclerosis, according to researchers here.
Moreover, the results of a small pilot study suggested a potential significant neuroprotective effect, including improvements in cognition and slowing of brain atrophy, found Nancy Sicotte, M.D., of the University of California at Los Angeles.
Also, during treatment with a topical testosterone gel, lean muscle mass increased significantly (P=0.02), Dr. Sicotte and colleagues reported in the May issue of Archives of Neurology.
The researchers cautioned that the study is "exploratory," but added that the results - especially the apparent neuroprotection - warrant further investigation.
Dr. Sicotte and colleagues noted that men are less likely than women to get multiple sclerosis and the onset tends to be later, possibly because of an interplay of sex hormones.
Also, in several animal models of autoimmune disease as well as in some human neurodegenerative diseases, exogenous testosterone has been shown to be protective, they said.
But the effects of testosterone supplements is not known in men with multiple sclerosis, they said, so the researchers enrolled 10 men in a crossover study, in which each volunteer served as his own control.
After a six-month pretreatment observations phase, each man was treated for 12 months with a testosterone gel - 10 grams daily, containing 100 mg of testosterone, rubbed on the upper arms.
At the start, all of the volunteers had low-normal serum testosterone levels, with a mean of 493 ng/dL. Over the course of the study, levels increased on average by 50%, to high normal, the researchers found.
By the end of the study, the men had gained on average 1.7 kilograms of lean muscle mass, compared with their pretreatment levels.
Cognition, as measured by the Paced Auditory Serial Addition Task, did not change during the first six months of treatment, but trended upward by nine months and was significantly improved (at P=0.008) after 12 months of therapy, the researchers found.
During the pretreatment phase and the first three months of treatment, brain volumes - as measured by magnetic resonance scanning -- decreased at an annualized rate of minus 0.81%, which was statistically significant at P<0.001.
But during the rest of the treatment period, brain atrophy slowed to an annualized rate of minus 0.26%, which was not significant (P=0.10). The difference represented a 67% reduction in the rate of brain volume loss, Dr. Sicotte and colleagues reported.
Interestingly, the effect on brain volume was seen in the absence of a marked anti-inflammatory effect, the researchers said, implying that testosterone may have a similar effect on non-inflammatory neurodegenerative diseases.
There were no adverse effects attributed to the testosterone, the researchers said.
Dr. Sicotte and colleagues cautioned that the results must be taken with a grain of salt because of the small sample size, and added that they may not apply to men with more aggressive disease.