Aromatase and endometriosis: estrogens play a role

Follicle-Stimulating Hormone Receptor Expression in Endometriotic Lesions and the Associated Vasculature: An Immunohistochemical Study

Follicle-stimulating hormone receptor (FSHR) is present on endothelial cells of blood vessels and endometrial glands of the proliferative and secretory endometrium. So far, the expression of FSHR in endometriosis has not been studied. We evaluated FSHR expression in 194 tissue specimens representing 3 relevant types of endometriosis: rectovaginal endometriotic nodules, ovarian endometriotic cysts, and peritoneal endometriotic implants. Specimens of normal endometrium were used as controls. Archival formalin-fixed and paraffin-embedded material was analyzed immunohistochemically with a highly specific monoclonal antihuman FSHR antibody using the peroxidase method. A robust vascular FSHR expression was found in all 194 patients, irrespective of the endometriosis lesion location. Follicle-stimulating hormone receptor was not detected in normal host tissues located more than 5 mm from the lesions. The endometriotic lymphatic vessels do not express FSHR. The density of FSHR-positive vessels in patients with rectovaginal endometriotic nodules was 46.0 ± 5.7 vessels/mm(2) Similar values were obtained for ovarian endometriotic cysts and peritoneal endometriosis. The density of FSHR-positive vessels associated with the core of rectovaginal endometriotic nodules was 2-fold higher than that of the perilesional, adjacent normal host tissue (64.2 ± 8.2 vs 27.2 ± 3.2 vessels/mm(2), respectively). Expression of FSHR was also detected either in endometriotic glandular epithelial cells, endometriotic stromal cells, or in both cell types (23%, 25%, and 21% of patients, respectively). Normal endometrium expressed FSHR predominately in basalis, in a cellular distribution dependent on hormonal environment. In conclusion, our data suggest novel FSHR expression in endometriotic lesions, qualitatively and quantitatively different from that of normal endometrium.

p53 Arg72Pro polymorphism confers the susceptibility to endometriosis among Asian and Caucasian populations

PURPOSE

Findings from studies on the association between the p53 Arg72Pro polymorphism and endometriosis susceptibility have so far been inconsistent. Therefore, we undertook a meta-analysis to clarify the association of p53 Arg72Pro polymorphism with the risk of endometriosis.

METHODS

Relevant studies were chosen by searching PubMed, Embase, the Cochrane Library databases, CNKI, Wanfang database, and CBM for articles published before and up to April 30, 2015. Two independent reviewers performed the eligibility evaluation and data extraction. The odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated for the overall risk estimate.

RESULTS

Eleven case-control studies involving 1834 endometriosis cases and 2331 controls were included. Pooled data analysis suggested that the p53 72Pro variant is a significant endometriosis risk factors in comparison to the 72Arg variant (Pro vs. Arg: OR = 1.298, 95 % CI 1.082-1.558; Pro/Pro vs. Arg/Arg: OR = 1.751, 95 % CI 1.130-2.711; Pro/Arg vs. Arg/Arg: OR = 1.530, 95 % CI 1.174-1.994), which was strengthened in the dominant model (Pro/Pro + Arg/Pro vs. Arg/Arg: OR = 1.570, 95 % CI = 1.181-2.087). In the stratified analysis by ethnicity and Hardy-Weinberg equilibrium (HWE) in the controls, we found strong associations in Asians and in studies that were consistent with HWE. However, the analyses of the revised American Fertility Society (rAFS) stage and the menopausal status subgroup did not reveal any significant associations.

CONCLUSION

In conclusion, the p53 Arg72Pro polymorphism was closely related to the risk of endometriosis, especially in Asian populations.

Metformin Suppresses Prostaglandin E2-Induced Cytochrome P450 Aromatase Gene Expression and Activity via Stimulation of AMP-Activated Protein Kinase in Human Endometriotic Stromal Cells

BACKGROUND

Cytochrome P450 aromatase (encoded by the CYP19A1/aromatase gene) plays a critical physiologic role in endometriosis. Metformin is known to suppress prostaglandin E2 (PGE2)-induced CYP19A1 messenger RNA (mRNA) expression in human endometriotic stromal cells (ESCs). However, the possible mechanism behind this suppression remains to be determined.

METHODS

In this study, ESCs were cultured with metformin, PGE2, and adenosine monophosphate (AMP)-activated protein kinase (AMPK) inhibitors. Expression of CYP19A1 mRNA and aromatase activity were measured by quantitative polymerase chain reaction and aromatase activity assay, respectively. The binding of the cyclic AMP response element-binding (CREB) protein to CYP19A1 promoter II (PII) was assessed by chromatin immunoprecipitation assay.

RESULTS

We demonstrated that metformin downregulated the expression of aromatase mRNA (32%) and activity (25%) stimulated by PGE2 (4.18-fold and 2.14-fold) in ESCs via stimulation of AMPK. Following PGE2 treatment, there was a marked increase in CREB binding to aromatase PII, while metformin attenuated the above-mentioned stimulation by 67%.

CONCLUSION

Metformin could inhibit PGE2-induced CYP19A1 mRNA expression and aromatase activity via AMPK activation and inhibition of CREB to CYP19A1 PII in human ESCs. The results of the present study suggest that metformin may have unique therapeutic potential as an antiendometriotic drug in the future.

Power over Pain: A Brief Review of Current and Novel Interventions for Endometriosis-Associated Pain

An estimated 10%-15% of women of reproductive age suffer from endometriosis and can be plagued with one or many forms of pain. It is no mystery that endometriosis is an extremely complex disease, with several factors leading to the predominant symptoms of infertility and pain. Although there are currently multiple options available for treating endometriosis-associated pain, none have the ability to completely relieve the symptoms. This review both highlights the current trends in treatment of endometriosis-associated pain and explores some novel options available for therapy directed towards oxidative stress, inflammation and nociceptive mechanisms of pain. A PubMed search was conducted to identify the most recent publications on the topic of pain associated with endometriosis, and further research was performed to clarify the mechanism by which current treatments target pain. Lastly, the authors include a review of pharmacological options at the forefront of endometriosis research. A more comprehensive understanding of the mechanisms behind endometriosis-associated pain will ultimately lead to more effective treatments and improved prognoses for patients.