New Ideas on What Causes Endometriosis
Surprisingly, bacteria may be involved
Endometriosis happens when tissue similar to the uterus lining grows in other places like the ovaries. Researchers are studying new ideas about what causes this common and painful condition.
Common Theories
Some existing theories are:
Retrograde menstruation — uterine tissue flows back through the fallopian tubes during menstruation and implants in the abdomen. But this happens in most women, yet not all get endometriosis.
Cell change — cells in the abdomen transform into endometrial-like cells. But it’s unclear what triggers this change.
Stem cells — rogue uterine stem cells travel and develop into lesions. But stem cells are rare in menstrual blood.
Hormones Play a Role
Oestrogen causes uterine lining growth. Endometriosis lesions have extra oestrogen receptors. They also have fewer progesterone receptors, causing resistance to progesterone which normally opposes oestrogen.
This hormonal imbalance promotes lesion growth and inflammation. Hormone suppressing medications can help treat endometriosis. But more research is needed on what causes the receptor abnormalities.
Immune System Dysfunction
Alterations in immune cells like macrophages, NK cells and T cells create an inflammatory environment in the abdomen. This likely enables lesions to establish and grow. But it’s unknown whether immune dysfunction is the cause or result of endometriosis.
Emerging Role of Bacteria
New DNA sequencing techniques detect bacteria deep in reproductive tissues previously thought to be sterile. Some bacteria may promote inflammation and lesion growth.
Fusobacterium bacteria in the uterus may provoke cell changes leading to endometriosis when they reach the abdomen via retrograde menstruation.
Imbalances between healthy and harmful bacteria in the uterus and vagina could contribute to the development of lesions. More research on bacterial influences is needed.
Looking Ahead
Endometriosis likely arises from a complex interplay of menstrual backflow, genetic susceptibility, hormones, immune factors, and microbial changes.
A better understanding of these root causes is essential for developing new treatments that don’t compromise fertility.
Sources:
DOI:https://doi.org/10.1016/j.isci.2023.108739
Emerging bacterial factors for understanding pathogenesis of endometriosis: iScience (cell.com)
