A hormone produced by the human placenta reduced the symptoms of multiple sclerosis in a small test group of women, explaining the oft-noted observation that women with this neurological disease report fewer symptoms during pregnancy.
The study, by researchers at UCLA's David Geffen School of Medicine, found that women in early stages of multiple sclerosis developed less inflammation in their brains and underwent encouraging changes in their immune function when given the hormone estriol for several months.
While the finding is positive, the scientists caution that the study is very preliminary, involving a handful of women and designed mostly to check whether the treatment was safe.
Multiple sclerosis is a disease in which the body's immune system attacks the insulation of nerve fibers, causing symptoms such as tingling and numbness, even blindness and paralysis. Typically developing during early adulthood, MS affects an estimated 1 in 10,000 adults in the United States. Twice as many women as men are afflicted with the condition.
Current medications, such as interferon beta-1a and glatiramer acetate, carry side effects such as flulike symptoms and depression and must be injected, leading to scarring at the injection site.
At one time, women with the disease were discouraged from having babies because symptoms had been observed to worsen after their pregnancies.
But patients and doctors had also noticed that during the pregnancy, symptoms noticeably improved. Scientists hypothesized that one of the hormones of pregnancy was the cause--and that the improvement was linked to immune system changes aimed at avoiding rejection of the fetus.
Estriol is produced by the placenta and is found in the human body in large amounts during the second and third trimester of pregnancy. When a group led by Dr. Rhonda Voskuhl, associate professor of neurology at UCLA, tested estriol in a mouse model for multiple sclerosis, they found that the animals' symptoms improved.
That led Voskuhl's team to begin a human study, published today in the journal Annals of Neurology.
In the study, Voskuhl and colleagues enrolled 12 women suffering from multiple sclerosis. Six of the women had a common, early version of the illness known as relapsing remitting multiple sclerosis, in which symptoms come and go. Another six patients had more serious and advanced illness.
