[P450Arom and estrogenic microenvironment of eutopic endometria in endometriosis]

Endometriosis, a common gynecologic disorder characterized by endometrial glands and stroma outside the uterus, is diagnosed by direct visualization of peritoneal and ovarian implants during laparoscopy.

To study the estrogenic microenvironment in eutopic endometria of women with and without endometriosis.

Eutopic endometria, obtained during laparoscopy from 23 women with endometriosis and 20 fertile cyclic women undergoing tubal sterilization, was studied. P450Arom mRNA expression (RT-PCR) was measured. Also, P450Arom activity was assessed measuring testosterone conversion to estradiol and the concentration of this last hormone in cultured endometrial explants.

Age and body mass index was similar in both groups studied. Seventy nine percent of endometria from women with endometriosis and in 29.4% from control group expressed P450Arom mRNA (p <0.01). The intensity of the band was higher in secretory endometria from women with endometriosis when compared to controls (p <0.01), but it was similar during the proliferative phase. Estradiol secretion to the culture media by proliferative endometria explants from women with endometriosis was 3-fold higher than secretory endometria (p <0.01) and endometria from control women in both phases. P450Arom activity, in the presence of testosterone, was 7-fold higher in endometrial cultures from women with endometriosis, when compare with the basal culture (p <0.01). However, in endometrial explant cultures from control women, this activity was not statistical different.

These results indicate that in women with endometriosis, the microenvironment in the endometria is estrogenic as a consequence of an increased expression and activity of the P450Arom.