Research on Antibiotics as a Treatment for Endometriosis

Understanding Endometriosis

Endometriosis is a chronic medical condition characterized by pelvic and lower abdominal pain, as well as infertility. Approximately 10% of women aged 25 to 40 are affected by this disorder, which significantly diminishes quality of life. Current treatments include surgery and hormone therapy; however, these options do not prevent the recurrence of endometriosis.

The Role of Bacteria in Endometriosis

One hypothesis concerning the etiology of endometriosis concerns the presence of bacteria in the reproductive tract. Research has shown that the bacterial communities in the reproductive tracts of women with and without endometriosis differ, with certain bacterial profiles linked to reproductive disorders.

Study Investigating Gut Bacteria and Endometriosis Progression

Researchers from the Department of Obstetrics and Gynecology at Washington University School of Medicine conducted a study to explore the hypothesis that gut bacterial communities might influence the progression of endometriosis. Their findings were published in the journal Human Reproduction.

The team employed a well-established mouse model for endometriosis. After inducing the condition in the mice, they administered drinking water containing a combination of four antibiotics: vancomycin, neomycin, metronidazole, and ampicillin. Aspartame was added to the water to mask the antibiotics’ taste. The antibiotic-treated mice were then compared to a control group that received only aspartame.

After three weeks of treatment, the mice were euthanized, and samples were taken from their gut and reproductive tract. The results revealed that the antibiotic-treated group exhibited smaller endometriotic lesions compared to the control group.

In a separate experiment, the researchers provided the antibiotics before the surgical induction of endometriosis. This group also showed smaller lesions in comparison to the control mice.

Implications of Antibiotic Treatment

These experiments indicate that antibiotic treatment may reduce the progression of endometriosis and inhibit the early growth of endometriotic lesions. The researchers further analyzed the gut bacterial communities of the antibiotic-treated mice, discovering that those without antibiotic treatment had greater bacterial diversity. Conversely, the lowest diversity was observed in the mice treated with antibiotics.

Metronidazole’s Potential as an Effective Treatment

The study also isolated the effects of metronidazole and neomycin on endometriosis. Mice treated with metronidazole exhibited smaller lesions compared to those treated with neomycin, in addition to fewer inflammatory markers present in the lesions.

Furthermore, metronidazole-treated mice were given fecal matter from other endometriosis-affected mice, resulting in endometriotic lesions that were comparable in mass and volume to those in the control group. This finding suggests that gut bacteria may play a crucial role in the development and progression of endometriosis.

Future Research Directions

Further investigations are essential to ascertain whether these findings are applicable to humans. If gut bacteria indeed influence the progression of endometriosis in human patients, this could pave the way for innovative treatment options.

Written by Jessica Caporuscio, PharmD

Reference: Chadchan SB, Cheng M, Parnell LA, et al. Antibiotic therapy with metronidazole reduces endometriosis disease progression in mice: a potential role for gut microbiota. Hum Reprod. 2019.