What’s next?
The chief limitation of human studies looking at mechanisms of endometriosis is that they are correlational: Tissue samples are collected from women with and without endometriosis, often through an invasive procedure such as laparoscopy or biopsy, at one point in time. Currently, the best tools for proving causation are animal models of endometriosis, such as the those used by Dr. Kondo’s and Dr. Kommagani’s teams.
Better diagnostic tools would solve that problem. The ultimate goal is a noninvasive test for endometriosis that would allow clinicians to follow women over time and permit the monitoring of disease progression, or regression, without the need for painful procedures. Such a diagnostic tool would facilitate rigorous longitudinal studies evaluating mechanisms of disease, as well as monitoring outcomes of clinical trials of new treatments.
Could stool samples be the answer?
The Japanese team found that women harboring Fusobacterium in endometrial tissue also had Fusobacterium in vaginal samples taken at the time of their hysterectomy – and stool samples can pick up changes in the gut microbiome.
“Vaginal swab or stool tests are probably the best and easiest for noninvasive early detection,” Dr. Kommagani said.
Spit tests for DNA would be even easier to obtain. Polygenic risk scores could be developed to estimate an individual’s risk of disease based on the number of variants, but Dr. Zondervan cautioned that not all the genes that account for endometriosis are known.
“The things that we found altogether explain about 5% of disease variability, basically – which is still not an awful lot,” she said.
Dr. Kondo’s work was supported by the Grant-in-Aid for Scientific Research, the Japan Society for the Promotion of Science, and the Research Grant of the Princess Takamatsu Cancer Research Fund. A patent method for detecting bacteria of genus Fusobacterium in order to diagnose endometriosis (WO2023/ 042714), was submitted (international publication date, March 23, 2023).
Dr. Kommagani’s work was funded, in part, by National Institutes of Health/National Institute of Child Health and Human Development grants R01HD102680, R01HD065435, and R00HD080742. He has no other conflicts of interest. Dr. Zondervan received funding from the Wellcome Trust (216767; 104036; 084766; 212904; 076113 and 085475) and also reported grants from Bayer AG, AbbVie, Volition Rx, MDNA Life Sciences, and Roche Diagnostics outside the submitted work.
Dr. Thomas is a pediatrician and epidemiologist living in Portland, Ore.
A version of this article originally appeared on Medscape.com.