Implantation of a retrogradely shed endometrium during menstruation requires an adequate blood supply, which allows the growth of endometriotic lesions. This suggests that the development of endometriosis can be impaired by inhibiting angiogenesis. The growth of endometriotic foci is impaired by commercial oncological antiangiogenic drugs used to block vascular endothelial growth factor (VEGF) signaling. The dopamine agonist cabergoline (Cb2) inhibits the growth of established endometriosis lesions by exerting antiangiogenic effects through VEGFR2 inactivation. However, the use of ergot-derived Cb2 is associated with an increased incidence of cardiac valve regurgitation. To evaluate the potential usage of non-ergot-derived dopamine agonists for the treatment of human endometriosis, we compared the efficacy of quinagolide with that of Cb2 in preventing angiogenesis and vascularization in a heterologous mouse model of endometriosis. Nude mice whose peritoneum had been implanted with eutopic human endometrial fragments were treated with vehicle, 50 mg/kg per day oral Cb2, or 50 or 200 mg/kg per day quinagolide during a 14-day period. At the end of the treatment period, the implants were excised in order to assess lesion size, cell proliferation, degree of vascularization, and angiogenic gene expression. Neoangiogenesis was inhibited and the size of active endometriotic lesions, cellular proliferation index, and angiogenic gene expression were significantly reduced by both dopamine agonists when compared with the placebo. Given that Cb2 and quinagolide were equally effective in inhibiting angiogenesis and reducing lesion size, these experiments provide the rationale for pilot studies to explore the use of non-ergot-derived dopamine agonists for the treatment of endometriosis in humans.

STUDY QUESTION Do oocytes from women with ovarian endometriosis (OE) have a different transcriptomic profile than those from healthy women? SUMMARY ANSWER Oocytes from endometriosis patients, independently of whether they came from the affected ovary, exhibited a differential transcriptomic profile compared to oocytes from healthy egg donors. WHAT IS KNOWN ALREADY Studies of endometriosis have sought to determine whether OE affects oocyte quality. While many reports indicate that oocytes recovered from endometriotic ovaries may be affected by the disease, other studies have found no significant differences among oocyte/embryo quality and fertilization, implantation and pregnancy rates in women with endometriosis. STUDY DESIGN, SIZE, DURATION This prospective study compared metaphase II (MII) oocytes (n = 16) from endometriosis patients (n = 7) to oocytes (n = 16) from healthy egg donors (n = 5) by single-cell RNA sequencing (scRNA-seq). Participants were recruited between December 2016 and February 2018 at IVI-RMA Valencia and Vigo clinics. PARTICIPANTS/MATERIALS, SETTING, METHODS Human MII oocytes were collected from healthy egg donors and OE patients aged 18–34 years, with a body mass index of <30 and >6 pre-antral follicles. RNA was extracted, cDNA was generated and libraries were constructed and sequenced. scRNA-seq data libraries were processed and statistically analysed. Selected genes were validated by quantitative real-time PCR. MAIN RESULTS AND THE ROLE OF CHANCE Our scRNA-seq results revealed an effect of endometriosis on global transcriptome behaviour in oocytes from endometriotic ovaries. The highest number of differentially expressed genes (DEGs) was found when oocytes from women with OE were compared to oocytes from healthy donors [520 DEGs (394 upregulated and 126 downregulated)], independently of whether oocytes came from an affected or unaffected ovary. Among the top 20 significant DEGs in this comparison, most were upregulated, including APOE, DUSP1, G0S2, H2AFZ, ID4, MGST1 and WEE1. PXK was the only downregulated gene. Subsequently, functional analysis showed 31 enriched functions deregulated in endometriosis patients (Benjamini P < 0.1), being 16 significant enriched functions considering Benjamini P < 0.05, which involved in biological processes and molecular functions, such as steroid metabolism, response to oxidative stress and cell growth regulation. In addition, our functional analysis showed enrichment for mitochondria, which are an important cellular component in oocyte development. Other functions important in embryo development, such as angiogenesis and methylation, were also significantly enriched. LARGE SCALE DATA All raw sequencing data are submitted in Gene Expression Omnibus (GEO) under accession number (PRJNA514416). LIMITATIONS, REASONS FOR CAUTION This study was restricted only to OE and thereby other anatomical entities, such as peritoneal and deep infiltrating endometriosis, were not considered. This is a descriptive study with a limited number of samples reflecting the difficulty to recruit human oocytes, especially from women with endometriosis. WIDER IMPLICATIONS OF THE FINDINGS This study suggests that OE exhibits a global transcriptomic effect on oocytes of patients in OE, independently if they come from an affected or unaffected ovary and alters key biological processes and molecular functions related to steroid metabolism, response to oxidative stress and cell growth regulation, which reduce oocyte quality. STUDY FUNDING/COMPETING INTEREST(S) This research was supported by IVI Foundation, the Spanish Ministry of Economy and Competitiveness through the Miguel Servet programme (CPII018/00002 to F.D.), the Sara Borrell Program (CD15/00057 to H.F.) and the VALi+d Programe (Generalitat Valenciana); ACIF/2016/444 to A.C.). The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER None

BACKGROUND Patients with endometriosis often experience infertility and have poor IVF outcomes, with low fertilization and pregnancy rates. Although many theories have tried to explain the mechanisms underlying infertility in these patients, none of them is conclusive. OBJECTIVE AND RATIONALE In this review, we discuss the pathologic mechanisms through which endometriosis likely leads to infertility along with the therapeutic options used to date to treat endometriosis-related infertility and, thereby, to improve IVF outcomes in patients with endometriosis. SEARCH METHODS We performed a comprehensive literature search of clinical outcomes in endometriosis and the molecular mechanisms contributing to oocyte quality using the PubMed database to identify human and animal studies published from 1992 until September 2020. In total, 123 manuscripts were included. OUTCOMES While some theories propose that endometriosis patients may have fertility problems as a result of decreased endometrial receptivity, others reinforce the idea that infertility could be associated with oocyte alterations and lower implantation rates. Single-cell RNA sequencing of oocytes from patients with endometriosis has identified dysregulated mechanisms involved in steroid metabolism and biosynthesis, response to oxidative stress and cell cycle regulation. Dysregulation of these mechanisms could result in the poor IVF outcomes observed in patients with endometriosis. Further, impaired steroidogenesis may directly affect oocyte and embryo quality. Increased oxidative stress in patients with endometriosis also has a detrimental effect on the follicular microenvironment, inducing cell cycle dysregulation in oocytes, poor oocyte quality, and infertility. Moreover, granulosa cells in the context of endometriosis undergo increased apoptosis and have an altered cell cycle that could adversely affect folliculogenesis, oocyte and embryo quality, and IVF outcomes. Endometriosis is also associated with inflammatory damage and impaired angiogenesis, which could be directly correlated with poor IVF outcomes. While therapeutic options using GnRH analogues, progestins and aromatase inhibitors do not improve endometriosis-related infertility, anti-inflammatory agents and antioxidant supplementation could improve oocyte quality as well as implantation and clinical pregnancy rates in patients with endometriosis. WIDER IMPLICATIONS Endometriosis is a heterogeneous disease whose pathogenesis is complex and could affect fertility by altering a collection of molecular mechanisms in oocytes. Thus, a single model is not sufficient to describe endometriosis-related infertility. Dysregulation of steroidogenesis, oxidative stress, cell cycle progression, inflammation and angiogenesis in the follicular environment and oocytes in individuals with endometriosis are all possible contributors to endometriosis-related infertility. Therefore, treatments targeting these mechanisms could be therapeutic alternatives to improve IVF outcomes for these patients.

Objective: To assess the effect of vitamin D (VitD) on human uterine leiomyomas through Wnt/b-catenin pathway inhibition, apoptosis induction, and cell growth arrest. Design: A prospective study comparing leiomyoma vs. myometrium tissues. Paired design study comparing human uterine leiomyoma primary (HULP) cells treated with or without VitD. Setting: University hospital. Patient(s): Human uterine leiomyoma and myometrium were collected from women (aged 35À52 years) without hormonal treatment. Intervention(s): Samples were collected from women undergoing surgery due to symptomatic uterine leiomyoma pathology. Main Outcome Measure(s): Uterine leiomyoma and myometrium tissues were analyzed by western blot (WB) to determine proliferation, Wnt/b-catenin, and apoptosis pathways. HULP cells were used to study VitD effect in cell proliferation (WB), cell cycle (flow cytometry), Wnt/b-catenin and apoptosis genes (polymerase chain reaction arrays), Wnt-related proteins (protein array), and apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling [TUNEL] assay). Results: Human leiomyoma tissues compared with matched myometrium showed higher proliferation (fold change ¼ 8.16; P¼ .0006) and altered Wnt/b-catenin pathway (fold change ¼ 5.5; P< .0001), whereas no differences in apoptosis were observed. VitD induced cell growth arrest and decreased proliferation in HULP cells (fold change ¼ 0.74; P¼ .007). Moreover, VitD decreased Wnt-pathway expression in HULP cells at gene (activity score ¼ À0.775; P< .001) and protein levels. However, VitD did not induce apoptosis expression. Conclusion: Increased proliferation and Wnt/b-catenin pathway deregulation play a role in the development and growth of leiomyomas, whereas apoptosis appears not to contribute. VitD exerts an antiproliferative action on HULP cells through cell growth arrest and Wnt/b-catenin pathway inhibition, but not through apoptosis regulation, suggesting VitD as an effective therapy to stabilize leiomyoma size and prevent its growth. (Fertil Steril Ò 2019;111:397-407. Ó2018 by American Society for Reproductive Medicine.) El resumen está disponible en Español al final del artículo.