Enhanced UGT1A1 Gene and Protein Expression in Endometriotic Lesions.

The cellular function in endometriosis lesions depends on a highly estrogenic milieu. Lately, it is becoming evident that, besides the circulating levels of estrogens, the balance of synthesis versus inactivation (metabolism) of estrogens by intralesion steroid-metabolizing enzymes also determines the local net estrogen availability. In order to extend the knowledge of the role of estrogen-metabolizing enzymes in endometriosis, we investigated the gene and protein expression of a key uridine diphospho-glucuronosyltransferase (UGT) for estrogen glucuronidation, UGT1A1, in eutopic endometrial samples obtained from nonaffected and endometriosis-affected women and also from endometriotic lesions. Although UGT1A1 messenger RNA (mRNA) expression was detected at similar frequencies in endometriotic lesions and in eutopic endometrial samples, the levels of mRNA expression were greater in deep-infiltrating endometriotic lesions and in non-deep-infiltrating lesions when compared with either control endometrium or eutopic endometrium from women with endometriosis. Overall, we observed that protein expression of UGT1A1 was significantly more frequent in samples from endometriotic lesions in comparison with endometria. In addition, expression of UGT1A1 protein was greater in deep-infiltrating than in non-deep-infiltrating endometriotic lesions. We suggest that the finding of increased expression of UGT1A1 in lesions versus endometria might be related to impairment of regulatory mechanisms, in response to a highly estrogenic milieu, and that this enzyme may be a new target for therapy.

Is cytochrome P450 3A4 regulated by menstrual cycle hormones in control endometrium and endometriosis?

The estrogen-metabolizing activities of cytochrome P450 (CYP) enzymes have been implicated in endometriosis. However, their regulation in various sources of endometrial tissue under different hormonal conditions has not been clarified. Our objective was to study the hormone regulation of a specific CYP enzyme, namely CYP3A4, in control (n = 15) and endometriosis patients (n = 42). To this end, we evaluated mRNA expression (using real-time PCR) of CYP3A4 in tissue samples classified according to the phase of menstrual cycle at which they were obtained as confirmed by the related circulating hormone levels. Protein expression was also evaluated by Western Blot. In order to further investigate the hormonal regulation of CYP3A4, stromal cells from ovarian endometriotic lesions were cultured with the prevailing hormones of the distinct phases of the menstrual cycle. We observed that all control and endometriosis tissues express CYP3A4. Nevertheless, changes in CYP3A4 gene expression related to cycle phase were only seen in the control eutopic endometrium and not in samples from endometriosis patients, with an increase in the luteal phase. Stromal cells isolated from ovarian endometriotic lesions expressed CYP3A4 and their exposure to luteal phase-mimicking hormones (estradiol + progesterone) reduced CYP3A4 mRNA in parallel with a diminished expression of the corresponding receptors, estrogen receptor alpha and progesterone receptor. Our findings suggest that steroid hormones are able to regulate CYP3A4 mRNA expression, although the circulating levels of these hormones can only regulate control endometrium and not endometriosis tissues, probably because of dysregulated local steroid concentration in these latter samples.

Increased expression of CYP1A1 and CYP1B1 in ovarian/peritoneal endometriotic lesions.

Endometriosis is an estrogen-dependent disease affecting up to 10% of all premenopausal women. There is evidence that different endometriosis sites show distinct local estrogen concentration, which, in turn, might be due to a unique local estrogen metabolism. We aimed to investigate whether there was a site-specific regulation of selected enzymes responsible for the oxidative metabolism of estrogens in biopsy samples and endometrial and endometriotic stromal cells. Cytochrome P450 (CYP) 1A1 and CYP1B1 mRNA and protein expressions in deep-infiltrating (rectal, retossigmoidal, and uterossacral) lesions, superficial (ovarian and peritoneal) lesions, and eutopic and healthy (control) endometrium were evaluated by real-time PCR and western blot. Using a cross-sectional study design with 58 premenopausal women who were not under hormonal treatment, we were able to identify an overall increased CYP1A1 and CYP1B1 mRNA expression in superficial lesions compared with the healthy endometrium. CYP1A1 mRNA expression in superficial lesions was also greater than in the eutopic endometrium. Interestingly, we found a similar pattern of CYP1A1 and CYP1B1 expression in in vitro stromal cells isolated from ovarian lesions (n=3) when compared with stromal cells isolated from either rectum lesions or eutopic endometrium. In contradiction, there was an increased half-life of estradiol (measured by HPLC-MS-MS) in ovarian endometriotic stromal cells compared with paired eutopic stromal endometrial cells. Our results indicate that there is a site-dependent regulation of CYP1A1 and CYP1B1 in ovarian/peritoneal lesions and ovarian endometriotic stromal cells, whereas a slower metabolism is taking place in these cells.

Effects of steroid hormone on estrogen sulfotransferase and on steroid sulfatase expression in endometriosis tissue and stromal cells.

Endometriosis is an estrogen-dependent disease that afflicts about 10% of women in their reproductive age, causing severe pain and infertility. The potential roles of female steroid hormones in modulating key estrogen-metabolizing enzymes, steroid sulfatase (STS) and estrogen sulfotransferase (SULT1E1), were investigated. The expression of STS and SULT1E1 mRNA in biopsy samples (n=78) of superficial and deep endometriotic lesions, eutopic endometrium of women with endometriosis and endometrium from control patients were compared according to the menstrual cycle phase. Increased STS gene expression was detected in superficial and deep-infiltrating lesions and a reduced SULT1E1 expression was also observed in the eutopic endometrium relative to the superficial lesions. Additionally, a significantly positive correlation was detected between STS and SULT1E1 mRNA expression levels in biopsy specimens collected from the endometriosis patients, and not in control individuals. The actions of female steroid hormones on SULT1E1 and STS expression were evidenced in endometriosis, revealed by increased expression levels in the luteal phase of the cycle. There was an increased STS expression in primary eutopic and ectopic endometrial stromal cells treated with estradiol and progesterone (representative of the luteal phase, n=3). Although an increased STS mRNA expression was observed in hormone-induced endometrial stromal cells in vitro, no difference could be detected between the hormone treatment groups in estradiol formation from estradiol sulfate measured by LC-MS-MS. Interestingly, a greater expression of STS was observed in stromal cells from eutopic endometrium with an agreement in estradiol formation originated from estradiol sulfate. The differential regulation of STS and SULT1E1 could provide insights for novel studies of the therapeutic use of STS inhibitors.

Location of the embryo-transfer catheter guide before the internal uterine os improves the outcome of in vitro fertilization.

The objective of this study was to assess whether positioning the embryo transfer (ET) catheter guide at the time of embryo expulsion, before or beyond the internal os, has an impact on IVF cycle outcome. We performed a retrospective study comparing IVF outcomes in relation to the ET guide position relative to the internal uterine os. We analyzed ultrasound-guided ETs in IVF-intracytoplasmic sperm injection (ICSI) cycles, performed with the tip of the ET catheter guide just before the internal os (group 1) and beyond the internal os (group 2). Implantation and pregnancy rates were significantly better in group 1 than in group 2, at 14.8% versus 11.8% and 57.3% versus 43.1, respectively. We conclude that passing the ET catheter guide beyond the internal os reduces implantation and pregnancy rates.