Peroxisome proliferator-activated receptor-γ coactivator 1α-mediated pathway as a possible therapeutic target in endometriosis.

STUDY QUESTION: Is a peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α)-mediated pathway involved in the development of endometriosis? SUMMARY ANSWER: PGC-1α plays critical roles in inflammation and cell proliferation of endometriotic tissues and may be involved in the development of endometriosis. WHAT IS KNOWN ALREADY: Expression levels of PGC-1α are higher in ovarian endometrioma (OE) than normal endometrium (NE). PGC-1α also stimulates aromatase activity and promotes local estrogen biosynthesis in OE. STUDY DESIGN, SIZE, DURATION: This is a case-controlled biological study using endometrial cells and tissues derived from 23 women with, and 10 women without, OE. PARTICIPANTS/MATERIALS, SETTING, METHODS: Ectopic endometriotic and eutopic endometrial stromal cells (SCs) were isolated and maintained in culture. PGC-1α was either overexpressed in the cells or knocked down using siRNA. The expression of PGC-1α and other factors during endometriosis was examined using real-time PCR and western blotting, cell proliferation was measured using Cell Counting Kit-8 (WST-8) assays and transcriptional activity was assessed using luciferase reporter assays. MAIN RESULTS AND THE ROLE OF CHANCE: PGC-1α overexpression promoted the proliferation of OESCs in a time-dependent manner (P < 0.01 versus control) but not NESCs. PGC-1α stimulated aromatase (P < 0.01 versus control) and interleukin (IL)-6/IL-8 mRNA expression levels (P < 0.05 versus control for each) and led to inhibitor kappa B phosphorylation protein expression and upregulation of the apoptosis inhibitors X-linked inhibitor of apoptosis protein and survivin at mRNA level (P < 0.05 versus control for each). HX531, a selective retinoid-X receptor-α (RXRα) antagonist, suppressed the PGC-1α-induced cell proliferation (P < 0.05 versus control), aromatase/IL-6/IL-8/survivin mRNA expression (P < 0.05 versus control for each) and transcription reporter activity of PGC-1α in a dose-dependent manner (P < 0.01 versus control). Moreover, HX531 downregulated PGC-1α-induced aromatase-promoter PI.3-II transcripts in OESCs, and PGC-1α knockdown reduced aromatase, IL-6/IL-8 and antiapoptotic factors mRNA expression (P < 0.05 versus control for each). Notably, the Histogram score, which was used for quantifying RXRα status, was markedly higher in OE than in NE tissue (P < 0.01). LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Only OE tissues were included in this study, while peritoneal and deep infiltrating endometriotic tissues were not. Therefore, these findings might not be generalized to other types of endometriosis. WIDER IMPLICATIONS OF THE FINDINGS: In OESC, PGC-1α stimulated cell proliferation and was involved in local estrogen biosynthesis, inflammation and apoptosis, and these effects of PGC-1α were inhibited by HX531. The suppression of PGC-1α-induced proliferation by HX531 in OESCs but not NESCs suggests that the PGC-1α-RXRα axis could play critical roles in promoting endometriosis. This is the first report of a relationship between PGC-1α and inhibitor of apoptosis proteins in endometriosis. Based on these findings, the PGC-1α-mediated pathway could represent a potential target in molecular therapy of endometriosis. STUDY FUNDING/COMPETING INTEREST(S): The study is supported in part by Grants-in-Aid for Scientific Research (15 K10681 and 15 K10726) from the Ministry of Education, Culture, Sports, Science, and Technology (Japan). The authors have no conflicts of interest to disclose.

Molecular detection of microbial colonization in cervical mucus of women with and without endometriosis.

PROBLEM: Intrauterine microbial colonization and its association with the pathogenesis of endometriosis via an innate immune cascade have been reported. As a potential source of microbial transmission, information on microbial colonization in cervical mucus is unknown. We investigated pattern of microbiota in the cervical mucus collected from women with and without endometriosis using next-generation sequencing (NGS) technology. METHOD OF STUDY: Cervical mucus samples were collected from women with (n = 30) and without (n = 39) endometriosis. The communities of microbiota in cervical mucus in the endometriosis group and the control group were examined by Gram staining and NGS targeting the V5-V6 region of 16S ribosomal RNA gene. Copy number of some target bacteria was detected by real-time PCR. RESULTS: We confirmed visual presence of bacteria in cervical mucus by Gram staining. NGS analysis showed that distribution of microbiota was similar in cervical mucus of women with and without endometriosis regardless of the phases of the menstrual cycle. In addition to predominant Lactobacilli spp., the populations of Corynebacterium, Enterobacteriaceae, Flavobacterium, Pseudomonas, and Streptococcus were increased in the endometriosis group. Of them, Enterobacteriaceae and Streptococcus were identified as the more significant candidates in the endometriosis group than in controls by real-time PCR (P < 0.05 for each). CONCLUSION: Our NGS analysis of cervical mucus indicated that among a variable microbiota, two candidates (Enterobacteriaceae and Streptococcus) were more frequently detected in women with endometriosis. Further investigation is needed to elucidate a mechanistic link of these bacteria in the pathophysiology of endometriosis.

Dienogest therapy during the early stages of recurrence of endometrioma might be an alternative therapeutic option to avoid repeat surgeries.

AIM: We aimed to evaluate whether hormonal therapy immediately after postsurgical recurrence of ovarian endometrioma controls disease progression and can be an alternative therapeutic option to avoid multiple repeat surgeries. METHODS: We enrolled 146 patients treated for endometrioma at the University Hospital of Kyoto Prefectural University of Medicine between 2009 and 2015. After laparoscopic cystectomy using the stripping technique, opening of cul-de-sac obliterations and complete resection of the deep infiltrating endometriosis lesions, the patients either received no treatment (n = 83), oral contraceptives (OC; n = 32) or dienogest (DNG; n = 27), depending on their medical history. Four patients were excluded because they changed their regimens during the follow-up period. All patients were followed up every 3 months. Patients who developed recurrence of endometrioma immediately received DNG, OC or gonadotropin-releasing hormone agonist. RESULTS: Overall, 16 patients developed a recurrence of the endometrioma (12 in the nontreatment group, three in the OC group and one in the DNG group). The 11 patients with recurrence were treated with DNG immediately after the diagnosis of recurrent endometrioma. Among them, seven patients continued treatment with DNG (2 mg) for 24 months. After 24 months of treatment with DNG, complete resolution of recurrent endometrioma was achieved in four (57.1%) of seven patients. There was no improvement in the three patients who received OC and one patient who underwent secondary surgery. CONCLUSION: DNG therapy early after recurrence of postsurgical endometrioma appears to be viable for reducing the risk of repeated surgery.