Thursday, February 29, 2024

How do you get endometriosis?

Short answer: no one really knows. Long answer: there are numerous theories as to why and when endometriosis develops although none of them have been proven conclusively. Some have big fancy names like retrograde menstruation (menstrual blood refluxing back into the body), metaplasia (residual embryonic cells that respond to hormones), or apoptosis suppression and alteration of endometrial cell fate. Or some go back to genetics, stem calls, immune dysfunction, or oxidative stress and inflammation. Endometriosis lesions can be found in embryos, thus highlighting that it can be laid down before birth. Studies do show there is a genetic component, with increased risks among those with relatives with endometriosis (for example in one study there was an 5.2 increased risk between sisters and 1.6 increased risk in cousins). The oldest theory of what causes endometriosis is that menstrual blood backflows into the pelvis and once there attaches and grows. However, this retrograde menstruation occurs in most individuals with a uterus, but only around 10% develop endometriosis. In addition, endometriotic lesions have distinct characteristics from that of regular endometrial tissue from the uterus.   

It matters how we get it, because some treatments are based on not only how endometriosis behaves and what relieves symptoms but also how it originates. While endometriosis’ origins continue to be an enigma, studies continue to highlight new information that can guide care in the future (see some studies below).

References

Crispi, S., Piccolo, M. T., D'avino, A., Donizetti, A., Viceconte, R., Spyrou, M., ... & Signorile, P. G. (2013). Transcriptional profiling of endometriosis tissues identifies genes related to organogenesis defects. Journal of cellular physiology228(9), 1927-1934. https://doi.org/10.1002/jcp.24358

Sourial, S., Tempest, N., & Hapangama, D. K. (2014). Theories on the pathogenesis of endometriosis. International journal of reproductive medicine2014. https://doi.org/10.1155/2014/179515

Rahmioglu et al. (2015. Genetics of Endometriosis. Woman’s Health. https://journals.sagepub.com/doi/pdf/10.2217/whe.15.41

 

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Theories on endometriosis from before birth:

       Crispi, S., Piccolo, M. T., D'avino, A., Donizetti, A., Viceconte, R., Spyrou, M., ... & Signorile, P. G. (2013). Transcriptional profiling of endometriosis tissues identifies genes related to organogenesis defects. Journal of cellular physiology228(9), 1927-1934. https://doi.org/10.1002/jcp.24358

       Laganà, A. S., Vitale, S. G., Salmeri, F. M., Triolo, O., Frangež, H. B., Vrtačnik-Bokal, E., ... & Sofo, V. (2017). Unus pro omnibus, omnes pro uno: a novel, evidence-based, unifying theory for the pathogenesis of endometriosis. Medical hypotheses103, 10-20. https://doi.org/10.1016/j.mehy.2017.03.032

       Signorile, P. G., Baldi, F., Bussani, R., Viceconte, R., Bulzomi, P., D'Armiento, M., ... & Baldi, A. (2012). Embryologic origin of endometriosis: analysis of 101 human female fetuses. Journal of Cellular Physiology227(4), 1653-1656.  https://doi.org/10.1002/jcp.22888

       Schuster, M., & Mackeen, D. A. (2015). Fetal endometriosis: a case report. Fertility and sterility, 103(1), 160-162. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0015028214022274

 

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Genetics:

       “… among sisters there was a 5.2-fold increase in the risk of being diagnosed with endometriosis”

European Society For Human Reproduction And Embryology. "Genetic Link To Endometriosis – Unique Icelandic Study Provides Further Proof." ScienceDaily. ScienceDaily, 5 March 2002. www.sciencedaily.com/releases/2002/02/020228073008.htm

        “…primary difference was the finding that women who had relatives with endometriosis had more severe disease, defined as stages III to IV.”

Dun, E. C., Taylor, R. N., & Wieser, F. (2010). Advances in the genetics of endometriosis. Genome medicine, 2(10), 75. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2988445/#!po=0.609756

       “Endometriosis was found in 8/136 (5.9%) first-degree relatives of patients and in 4/134 (3.0%) first-degree relatives of controls in the real-case analysis”

Nouri, K., Ott, J., Krupitz, B., Huber, J. C., & Wenzl, R. (2010). Family incidence of endometriosis in first-, second-, and third-degree relatives: case-control study. Reproductive Biology and Endocrinology8(1), 85. https://pubmed.ncbi.nlm.nih.gov/20618992/

       "...the study identified 19 genetic variants associated with endometriosis, and many of those variants are also associated with other serious health conditions such as ovarian cancer, cardiovascular disease and high cholesterol....In this case the study found several variants in genes involved in sex hormone metabolism, specifically the genes GREB1, FN1, KDR, CCDC170, ESR1, SYNE1, and FSHB." https://blog.23andme.com/23andme-research/endometriosis/