Scientists may have discovered a potential cause of endometriosis, a painful condition in which the uterine lining grows outside of the uterus. Endometriosis affects approximately 10% of women, however, the causes are poorly understood.
A new study, published in Science Translational Medicine, detected a bacteria, called Fusobacterium, in over 60% of women with endometriosis.
As Healthline reports, the researchers also tested treatments in mice and found that antibiotics targeting Fusobacterium may reduce the size and frequency of lesions associated with endometriosis. Though the findings suggest microbes could play a role in the development of endometriosis, more research is needed to understand the relationship and whether antibiotics may be an effective treatment in humans.
Researchers hope the findings will lead to new treatment options for people with endometriosis, as the condition is notoriously difficult to diagnose and treat. “This study showing that there is a potential infectious etiology transforming normal cells into inflammatory cells triggering endometriosis is extremely interesting as targeted antibiotic therapy will definitely contribute to decreasing symptomatic disease,” Dr. David Herzog, the director of gynecology and minimally-invasive gynecologic surgery at Staten Island University Hospital, told Healthline.
The researchers recruited 155 women in Japan — 79 of whom had endometriosis and 76 who did not. They took vaginal swabs of the participants and found that about 64% of the women with endometriosis tested positive for a bacteria called Fusobacterium.
Of those who did not have endometriosis, 7% tested positive for Fusobacterium. “The presence of this bacteria in the vaginal swab samples from patients with endometriosis was significantly greater than from patients without endometriosis,” Dr. Jane Frederick, a reproductive endocrinologist who specializes in fertility and infertility and Medical Director of HRC Fertility in Orange County, California, said.
In a study done with mice, researchers investigated whether certain antibiotics, administered vaginally, may reduce the size and frequency of the lesions associated with endometriosis. They found that antibiotics reduced the amount of Fusobacterium in the mice and appeared to delay the development of endometriosis and shrink the number and size of the lesions.
The researchers say the report suggests antibiotics could be an effective treatment for some cases of endometriosis. More research is needed to better understand why this bacteria may lead to endometriosis and how antibiotics may help treat the condition. A clinical trial in women is now being conducted to determine if antibiotics may help with endometriosis.
Currently, the exact causes of endometriosis are not known. “There are many responsible factors, possibly including genetic, immunological and hormonal reasons,” Frederick said. Because the causes of endometriosis are unclear, it can be difficult to treat the condition.
Many researchers believe that retrograde menstruation — which occurs when menstrual blood period flows upward through the fallopian tubes and into the pelvis instead of out your vagina — contributes to endometriosis, however, many women with endometriosis do not experience this phenomenon. Though most reproductive-aged women experience retrograde menstruation, only a small percentage (10 to 15%) develop endometriosis.
Per the new findings, other mechanisms, like microbes, may be at play. “Endometriosis is a multifactorial disease, and its cause is difficult to attribute to a single factor,” says Frederick. Currently, hormonal medications — like birth control — and surgery to remove the affected tissue are the most common treatments for endometriosis.
“The cause of endometriosis is unknown, which is why this type of research is being conducted,” says Herzog.
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