An Oklahoma Medical Research Foundation scientist is a step closer to understanding a link between female obesity and multiple sclerosis.
His recent discovery, published Tuesday in the journal Cell Metabolism, may also help explain why the autoimmune disease affects far more women than men.
“Previous studies had established that obesity during female adolescence creates a greater risk of developing MS later,” said OMRF scientist Bob Axtell, Ph.D. “But those studies have shown that this was only true for females. The same connection doesn’t seem to be there for males.”
Axtell sought to understand how and why obesity seems to predispose some females to developing MS. Axtell studied various biological measures of obese male and female patients at OMRF’s MS Center of Excellence, as well as obese but otherwise healthy people of both sexes.
He collaborated with Shannon Dunn, Ph.D., from the University of Toronto, who conducted similar experiments in lab mice bred to have an MS-like condition.
Both studies found elevated levels of inflammation in obese females, but not in obese males.
“We’re not clear why inflammation would affect one gender more than the other, but that inflammation seems to be what predisposes these women not only for MS, but also for other autoimmune diseases,” Axtell said. “From existing data, we believe that this effect is set up during adolescence.”
Females today comprise about 80% of new MS cases, according to the National Multiple Sclerosis Society. Forty years ago, that gender gap was nearly negligible. Axtell believes that significant change may correspond to America’s increase in childhood obesity, which has more than tripled since the early 1970s.
MS is a chronic autoimmune disease affecting the central nervous system. Symptoms can include vision impairment, numbness and tingling, focal weakness, bladder and bowel dysfunction, and cognitive impairment. The disease affects about 1 million Americans and an estimated 2.3 million worldwide, according to the National MS Society.
Gabriel Pardo, M.D., who heads OMRF’s MS Center of Excellence and treats thousands of MS patients there, says the new study represents an important addition to researchers’ and healthcare providers’ body of knowledge.
“We need to better understand the molecular underpinnings of this disease so that we can mitigate those factors before the onset of MS,” he said. “But this study also provides a cautionary example pointing to another danger of obesity.”
Axtell’s study was funded by grant Nos. R01AI137047-03 from the National Institute of Allergies and Infectious Diseases, and R01EY027346-04 from the National Eye Institute, both of which are part of the National Institutes of Health.
