Factors Influencing the Role of Stem Cells in the Pathogenesis of Endometriosis
Endometriosis is known as the leading cause of infertility, affecting 10-15% of reproductive-aged women. However, up until now its exact pathogenesis has not yet been established, causing it to be often under-diagnosed and mistreated. Retrograde menstruation theory which was established by Sampson remains the most widely accepted one even though other theories also start to emerge. Recently, it has also been postulated that stem cells play a role in the pathogenesis of endometriosis. This can provide an enlightenment regarding processes which are inadequate to be explained by retrograde menstruation theory alone. Such issues include the controversy on why endometriosis only happens in 10-15% of women if retrograde menstruation occurs in up to 90% of them.
Speculation that stem cells are also shed alongside with the retrograde menstruation blood is strengthen by the discoveries of stem cells marker such as hTERT, OCT-4, SSEA-4, and NANOG. However, such presence may not benefit the disease progression if there is no alteration in the stem cells themselves. Apparently, OCT4, SOX2, and TWIST1 are found to be unregulated in endometriotic tissue and endometrium of endometriosis patient. In addition, researchers have also found dysregulation in the micro-RNA. Moreover, findings also suggest the involvement of bone marrow-derived stem cells in the pathogenesis of endometriosis. They can explain how endometrial tissue may be implanted in distant sites. To sum up, the role of stem cells in the pathogenesis of endometriosis is influenced by many factors, some of which include genetic alterations, sex hormone dysregulation as well as tissue injury.