A new study has discovered a possible cause of endometriosis, fusobacterium. Endometriosis occurs when endometrial cells grow outside the uterus, which can cause life-altering pain and even infertility.
When endometrial cells are outside the uterus, they still respond to menstruation. According to the Mayo Clinic, endometrial cells thicken, break down, and are eliminated by releasing blood during a period.
When endometrial cells are not in the uterus, they still thicken and bleed during a period, but they have no way of exiting the body. Now, the blood is trapped inside of the abdomen instead of being excreted.
This causes inflammation, irritation, and, ultimately, pain.
Approximately 10% of women of reproductive age experience endometriosis worldwide. Until recently, upward flow of blood into the fallopian tubes during periods was thought to be one of the only possible causes of endometriosis. Genetic predisposition or irregular hormone levels were other theories, but the exact cause remained unknown.
This study found a potential, previously unthinkable cause, fusobacterium. According to the study’s senior author, Yutaka Kondo, PhD, “Previously, nobody thought that endometriosis came from a bacterial infection, so this is a very new idea.”
There are many types of fusobacterium, and some are harmless. Yet, others can cause oral diseases and other head or neck infections.
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The Endometriosis Study Details
In this study, 76 healthy women and 79 women with endometriosis provided vaginal swab samples. The researchers from Nagoya University Graduate School of Medicine found fusobacterium in 64% of women with endometriosis and in <10% of healthy women.
This suggests that fusobacterium could play a role in the development of endometriosis in certain cases.
It was theorized that fusobacterium could change the structure and ability of certain endometrial cells. The researchers performed an in vitro experiment to test this hypothesis. They found that when endometrial cells called “quiescent fibroblasts” were exposed to fusobacterium, they gain the ability to move.
When these cells gain the ability to move, they can migrate to areas outside of the uterus.
The researchers continued their experiments by exposing mice to fusobacterium. This was done to determine if fusobacterium caused changes like those found during the in vitro experiment.
In this model, the changes to the cells occurred, and symptoms of endometriosis were observed. More importantly, these changes were reversed by administration of antibiotics.
These findings indicate a potential therapy route for some women with endometriosis, but do not to jump to conclusions.
First, this study only administered antibiotics to mice known to have fusobacterium. Second, not all women with endometriosis were found to have fusobacterium. Third, we do not know if fusobacterium is present during all stages of the development of endometriosis.
This is a promising study that could lead to effective treatments for endometriosis, but more research is needed to support these findings.
References From Our Article
- Muraoka, A., Suzuki, M., Hamaguchi, T., Watanabe, S., Iijima, K., Murofushi, Y., Shinjo, K., Osuka, S., Hariyama, Y., Ito, M., Ohno, K., Kiyono, T., Kyo, S., Iwase, A., Kikkawa, F., Kajiyama, H., & Kondo, Y. (2023). Fusobacterium infection facilitates the development of endometriosis through the phenotypic transition of endometrial fibroblasts. Science translational medicine, 15(700), eadd1531. Read it here.
- Malhi, S. (2023). A new clue to endometriosis, an agonizing and poorly understood disease. Washington Post. Read it here.
- Mayo Clinic. (2018). Endometriosis – Symptoms and Causes. Read it here.
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