A new study claims men and women's reproductive hormones may play key roles in the development of multiple sclerosis.1
Doctors at Rome's La Sapienza University set out to "investigate the relation between sex hormone concentrations and characteristics of tissue damage on conventional magnetic resonance imaging (MRI) in men and women suffering form relapsing-remitting MS."
The study was initiated on the heels of other research that found gender differences in the incidence of the disease.2
Sex Hormones in the Pathology of MS
Carlo Pozzilli, MD, PhD, a professor of Neurological Sciences, and his colleagues studied a group of 60 people with MS. Each had the relapsing-remitting form of the disease, in which people experience clearly-defined flare-ups, followed by partial or complete recovery periods free of disease progression. This is the most common form of the illness.3 Each of them had had the disease for about six years, on average.
None of the patients had been treated with interferon before the study, nor had they experienced any relapses or used steroids in the two months prior to the study's initiation. The women in the study were not using contraceptives, nor had they been prescribed hormone replacement therapy (HRT) for any reason. Their menstrual cycles were also normal.
To determine whether certain reproductive hormones somehow underlie the development of MS, Pozzilli andi his team measured levels of the hormones in the patients and compared their results with those of 36 healthy volunteers. Women's hormone levels were measured throughout their menstrual cycle since they can vary during this time.
Each MS patient also underwent MRI scans to detect any changes in the progression of the disease. Scanning also allowed the researchers to see how MS had caused damage to the patients' brains, or how much inflammation had occurred as a result of the disease.
Two Hormones May be Responsible
At the end of the study, Pozzilli and his colleagues determined that only testosterone and estrogen played key roles in the pathology of MS. "Testosterone was significantly lower in women with MS than in controls," they noted. "The lowest levels were found in women with a greater number of [brain] lesions."
The scientists also noted a close relationship between testosterone levels and both tissue damage and clinical disability. That is, women with MS and abnormally low levels of testosterone tended to have inflammation more often as seen on their brain scans than in those with MS and normal testosterone levels. Conversely, women with the disease and abnormally high levels of testosterone were more likely to have irreversible brain tissue damage due to MS.
"In men, there was a positive correlation between [estrogen] concentrations and brain damage," they wrote. Specifically, men with the illness and the highest levels of estrogen were more likely to have larger amounts of brain tissue damage, Pozzilli's group learned.
"The hormone related modulation of pathological changes supports the hypothesis that sex hormones play a role in the inflammation, damage, and repair mechanisms typical of MS," wrote the investigators. The significance of this, however, needs to be addressed in future studies, they added.
1. Tomassini V, Onesti E, Mainero C et al. Sex hormones modulate brain damage in multiple sclerosis: MRI evidence. J Neurol Neurosurg Psychiatry 2005 Feb;76(2):272-5.
2. Voskuhl RR. Gender issues and multiple sclerosis. Curr Neurol Neurosci Rep 2002 May;2(3):277-86.
3. National Multiple Sclerosis Society. What is Multiple Sclerosis? Available at: http://www.nationalmssociety.org/What%20is%20MS.asp. Accessed April 8, 2005.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
