Endometriosis, a condition in which the uterine lining (known as the endometrium) grows outside the uterus, can be incredibly painful and sometimes debilitating. To make matters worse, researchers know woefully little about it. A study published on June 14 in the journal Science Translational Medicine, however, presents a novel connection between the chronic condition and a common bacteria. This study marks the first time this bacterium has been implicated in female reproductive health issues.
The Japanese researchers zeroed in on fusobacterium, which typically dwells in the mouth and gastrointestinal tract. The team took vaginal swabs from 79 participants with endometriosis and 76 without it. They found that 64 percent of the endometriosis group tested positive for the bacterium in their uterine lining. On the other hand, less than 10 percent of participants without endometriosis tested positive for it.
Cancer biologist Yutaka Kondo from Nagoya University Graduate School of Medicine, and co-author of the study, told the Washington Post, “Previously, nobody thought that endometriosis came from a bacterial infection, so this is a very new idea.”
To further examine the link between fusobacterium and endometriosis, the researchers turned to a mouse model. They injected the bacterium into mice, which correlated with an uptick in endometriotic lesions. These lesions shrank in size and number, however, in response to antibiotics, which indicates the fusobacterium plays some part in worsening endometriosis. This trial is useful to demonstrate the bacterium’s effects on lesions, but mice do not menstruate or spontaneously form endometrial lesions.
While some types of fusobacterium are innocuous, others can induce severe infections like periodontitis and tonsilitis.
Still, this study leads to no treatment options yet. The paper’s abstract states: “Our data support a mechanism for the pathogenesis of endometriosis via Fusobacterium infection and suggest that eradication of this bacterium could be an approach to treat endometriosis.” The dream is for it to serve as a jumping-off point for future development.
Considering the only permanent treatment for endometriosis right now is a hysterectomy, it’s at least a step in the right direction. Up to 15 percent of people of reproductive age with uteruses have endometriosis.
Elise Courtois, a genomicist who studies the disease at the Jackson Laboratory, told Nature she would like to see future studies in more diverse populations.
