Epithelial-Mesenchymal Transition in Endometriosis-When Does It Happen?

Area of Science:

• Gynecology
• Cell Biology
• Pathophysiology

Background:

• Epithelial-mesenchymal transition (EMT) is a cellular process involving loss of epithelial traits and gain of mesenchymal characteristics.
• EMT is implicated in various biological processes and diseases, including recently described roles in endometriosis.
• Key EMT pathways and markers (e.g., Twist, Snail, ZEB1/2, cadherins) are known to be involved.

Purpose of the Study:

• To review and analyze the role of EMT pathways in the pathogenesis of endometriosis.
• To compare EMT marker expression in eutopic and ectopic endometrial tissues.
• To investigate the potential contribution of partial EMT to endometriotic lesion development.

Main Methods:

• Review of existing literature on EMT in endometriosis.
• Comparative analysis of EMT marker expression in eutopic and ectopic endometrium.
• Examination of cell-cell contact alterations and epithelial phenotype changes.

Main Results:

• Subtle changes in EMT markers were observed in the eutopic endometrium of women with endometriosis compared to controls.
• Significant alterations in EMT-related marker expression were predominantly found in ectopic endometrial tissues (ovarian, peritoneal, deep infiltrating endometriosis).
• Limited changes in cell-cell contacts and no significant alteration in the epithelial phenotype were noted in eutopic endometrium, suggesting partial EMT.

Conclusions:

• Partial EMT is likely not a prerequisite for the initial detachment of endometrial cells in endometriosis.
• The microenvironment of ectopic sites appears to significantly influence EMT marker expression in endometriotic implants.
• EMT pathways are differentially regulated in endometriosis, with greater involvement in ectopic lesions compared to eutopic endometrium.