Nachweis der Progesteronrezeptor-Isoformen im eutopen Endometrium bei Endometriose

Aim of this study was to characterise the endometrium of women with endometriosis. We studied immunohistochemically the expression of the progesterone receptor isoforms A and B in eutopic endometrium and compared their expression in patients with (n=24) and without (n=15) endometriosis. The expression of the progesterone receptor isoforms turned out to be dysregulated in endometriosis. There were no cyclical changes as in healthy patients without endometriosis. Although patients of our study without endometriosis showed symptoms like chronic pelvic pain, dyspareunia, dysmenorrhoe or infertility, they showed the typical changes of PR-expression during the menstrual cycle. Both receptor isoforms increased during the proliferative phase in epithelium as well as in stroma. In epithelial cells, they decreased during the secretory phase of the cycle while PR-A was still detectable in the stromal cells in the late secretory phase. In eutopic endometrium of patients with endometriosis, PR-A was also detectable in stromal cells of the secretory phase, while there was no comparable increase during the proliferative phase in epithelium and stroma. In some samples of both proliferative and secretory phase no PR-B could be detected in epithelium as well as in stroma, while some other samples of the same phase of the cycle showed a strong expression. Regarding the complete tissue sections we found strong alterations in progesterone receptor expression pattern. So the different parts of the sections showed different progesterone receptor expression. We consider that the detection of the progesterone receptor isoforms alone is not sufficient to characterise the endometrium of patients with endometriosis, but the dysregulation of their expression may in addition to other markers refer to endometriosis. Whether the different expression pattern of progesterone receptor isoforms is responsible for the development of endometriosis or is rather a result remains to be elucidated in further studies.