P-436 EndoTime: Non-categorical timing estimates for luteal endometrium

Study question

Can expression measurements of a small panel of genes be used to develop a continuous, non-categorical model for the improvement of endometrial biopsy timing accuracy?

Summary answer

Measuring expression levels of six genes (IL2RB, IGFBP1, CXCL14, DPP4, GPX3, and SLC15A2) is sufficient to obtain and assess substantially more accurate timing estimates.

What is known already

Commercially available endometrial timing approaches based on gene expression require much larger gene sets and use a categorical approach that classifies samples as pre-receptive, receptive, or post-receptive.

Study design, size, duration

Gene expression was measured by RT-qPCR in different sample sets, comprising a total of 664 endometrial biopsies obtained 4 to 12 days after a self-reported positive home ovulation test. A further 36 endometrial samples were profiled by RT-qPCR as well as RNA-sequencing.

Participants/materials, setting, methods

A computational procedure, named ‘EndoTime’, was established that models the temporal profile of each gene and estimates the timing of each sample. Iterating these steps, temporal profiles are gradually refined as sample timings are being updated, and confidence in timing estimates is increased. After convergence, the method reports updated timing estimates for each sample while preserving the overall distribution of time points.

Main results and the role of chance

The Wilcoxon rank-sum test was used to confirm that ordering samples by EndoTime estimates yields sharper temporal expression profiles for held-out genes (not used when determining sample timings) than ordering the same expression values by patient-reported times (GPX3 : p < 0.005; CXCL14 : p < 2.7e-6; DPP4 : p < 3.7e-13). Pearson correlation between EndoTime estimates for the same sample set but based on RT-qPCR or RNA-sequencing data showed high degree of congruency between the two (p = 8.6e-10, R-squared = 0.687). Estimated timings did not differ significantly between control subjects and patients with recurrent pregnancy loss or recurrent implantation failure (p > 0.05).

Limitations, reasons for caution

Timing estimates are informed by glandular gene expression and will only represent the temporal state of other endometrial cell types if in synchrony with the epithelium. Additionally, methods that estimate the day of ovulation are still required as these data are essential inputs in our method.

Wider implications of the findings

Our method is the first to assay the temporal state of endometrial samples on a continuous domain, enabling accurate temporal profiling of any gene in luteal phase biopsies for a wide range of research applications and, potentially, clinical use. It is freely available, open-source software including supporting data sets.

Trial registration number

Not applicable

O-302 Lower expression of AHCY is associated with increased miscarriage risk

Study question

Are alterations in the transcript levels of genes from the methionine cycle associated with maternal associated miscarriage risk?

Summary answer

Lower expression of AHCY is associated with a greater number of prior pregnancy losses

What is known already

Around 15% of pregnancies end in miscarriage, and the risk of recurrence increases with each pregnancy loss. Aberrant differentiation (decidualization) of endometrial stromal cells into specialised decidual cells to accommodate implantation is a key maternal factor for miscarriage risk.

Our previous work identified secretory changes in cysteine and methionine metabolites upon decidualization. The methionine cycle contributes to vital cellular functions, including producing methionine for proliferation, regulating cell differentiation, and S-adenosylmethionine (SAM) production. SAM is required for protein, RNA and DNA methylation, thereby influencing pathways at the metabolic, epigenetic, and proteomic levels. AHCY clears S-adenosylhomocysteine (SAH), reducing its inhibition of methylation.

Study design, size, duration

Endometrial biopsies (n = 250) were collected during the luteal phase (LH + 6-11). Patients were grouped based on their miscarriage history. Accordingly, expression of genes from the methionine cycle were quantified using RT-qPCR.

Participants/materials, setting, methods

Endometrial biopsies were obtained, with written informed consent, from women attending the Implantation Clinic at University Hospitals Coventry and Warwickshire NHS Trust, following transvaginal ultrasounds to exclude uterine pathology. Isolated RNA was converted into cDNA. Expression of AHCY, AMD1, BHMT2, CBS, MAT2A, MAT2B, and MTR were normalised to L19. Statistical analysis was performed in Graphpad Prism; with significance accepted at p < 0.05. AHCY was silenced in an endometrial cell line to determine its effect on decidualization.

Main results and the role of chance

This study reports a distinct reduction in expression of methionine cycle genes (MAT2A, AHCY, AMD1, MTR, BHMT2) in the late-luteal phase of the cycle consistent with a reduction in proliferation.

By plotting percentile graphs based on the statistical distribution in gene expression for each day of the luteal phase, comparisons have been made between groups.

AHCY expression is significantly reduced in patients with increasing number of prior miscarriages, particularly between 0-2 and 5+ previous miscarriages (p = 0.0334). Neither patient age nor BMI are a factor in this reduced expression.

In contrast, there is a stromal specific increase in AHCY upon decidualization in vitro, suggesting it is required in the decidua. Silencing AHCY in an endometrial cell line significantly reduces PRL expression upon decidualization. Reduction in AHCY may lead to a decreased “methylation potential” as SAH cannot be cleared. SAH accumulation inhibits methylation, and limits SAM production, thus compounding its effect.

Decreased methylation potential could prevent differentiation of the stromal compartment, resulting in lower levels of PRL, and altering decidual timing. Therefore, an embryo may implant into a tissue primed for disintegration, resulting a miscarriage.

In summary, AHCY may contribute to aberrant decidualization augmenting the risk of miscarriage.

Limitations, reasons for caution

Results are based on endometrial biopsies from an implantation clinic, therefore studies into biopsies from women with normal reproductive histories should also be analysed. Further functional studies are needed to ascertain the mechanism of action of AHCY in miscarriage.

Wider implications of the findings

This study identified that a decrease in AHCY in whole endometrial tissue is associated with increased risk of miscarriage. Further, silencing AHCY perturbed decidual marker expression. Thus, AHCY may act as a biomarker for atypical decidualization, and the clearance of SAH may be a potential treatment.

Trial registration number

N/A

O-129 Lactobacillus deplete vaginal microbial composition is associated with chromosomally normal miscarriage and local inflammation

Study question

To investigate the vaginal microbial composition and the local immune response in chromosomally normal and abnormal miscarriages and compare this to uncomplicated pregnancies delivering at term.

Summary answer

We show that euploid miscarriage is associated with a significantly higher prevalence of Lactobacillus spp. deplete vaginal microbial communities compared to aneuploid miscarriage.

What is known already

Emerging evidence supports the role of the vaginal microbiota in adverse pregnancy outcome, but the underlying mechanisms are poorly understood. A dominance of Lactobacillus spp. in pregnancy provides protection against pathogenic bacteria by producing lactic acid and antimicrobial compounds. A depletion in Lactobacillus spp. is often linked to adverse pregnancy outcomes.Current work also implicates the reproductive tract microbiota as a key modulator of local inflammatory and immune pathways. We have previously shown that miscarriage is associated with vaginal dysbiosis but without knowledge of the cytogenetic status of those miscarriages or the local immune profile.

Study design, size, duration

This study was a prospective observational cohort study based at Queen Charlotte’s & Chelsea Hospital, Early Pregnancy Unit, London between March 2014-February 2019. Vaginal swabs were collected from the posterior vaginal fornix of 167 patients.

Participants/materials, setting, methods

We used 16S rRNA gene based metataxonomics to interrogate the vaginal microbiota in a cohort of 167 women, 93 miscarriage patients (54 euploid and 39 aneuploid using molecular cytogenetics) and 74 women who delivered at term and correlate this with the aneuploidy status of the miscarriages. We also measured the concentrations of IL-2, IL-4, IL-6, IL-8, TNF-α, IFN-γ, IL-1β, IL-18 and IL-10 in cervical vaginal fluid using Human Magnetic Luminex Screening Assay (8-plex).

Main results and the role of chance

We show that euploid miscarriage is associated with a significantly higher prevalence of Lactobacillus spp. deplete vaginal microbial communities compared to aneuploid miscarriage (P=0.008). In women having Lactobacillus spp. deplete vaginal microbial communities, euploid miscarriage associates with higher concentrations of pro-inflammatory cytokines IL-1β, IL-8, IL-6 (P<0.001, P=0.01 and P<0.001 respectively) and lower concentrations of anti-inflammatory cytokines IL10 (P<0.001) when compared to viable term pregnancy. We identified Prevotella bivia and Streptococcus as particularly common in euploid miscarriage and as drivers of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α). Co-occurrence network analyses revealed low levels of co-occurrence between Lactobacillus crispatus and other organisms and strong co-occurrence between Streptococcal species. Our data show a combination of both an adverse vaginal microbiota and a cytokine response to it influences early pregnancy outcome. Although this may be a reflection of intrinsic maternal immune response, it appears that the cytokine response is largely driven by the bacterial taxa present in the vagina, which presents an opportunity for specific, directed intervention. The negative co-occurrence between L.crispatus and all other organisms suggests a possible therapeutic role for probiotics containing this organism. The influence of Streptococci also suggests a potential benefit of targeted antibiotics with probiotics for some patients.

Limitations, reasons for caution

There were no longitudinal samples in this cohort and our results are based on the assumption that the vaginal microbial composition is stable throughout the first trimester.Future longitudinal studies with larger sample sizes are needed to corroborate these findings and provide insights to the mechanisms that trigger the inflammatory response.

Wider implications of the findings

These findings support the hypothesis that the vaginal microbiota plays an important aetiological role in euploid miscarriage and may represent a target to modify the risk of pregnancy loss.

Trial registration number

n/a

Regulation of Platelet Aggregation and Adenosine Triphosphate Release In Vitro by 17β-Estradiol and Medroxyprogesterone Acetate in Postmenopausal Women

Clinical studies have suggested that hormone replacement therapy (HRT) may reduce the risk of coronary heart disease in postmenopausal women. Although progestins are commonly added to HRT preparations for uteroprotection, the perceived beneficial cardiovascular effects of HRT are thought to be mediated predominantly by the estrogen component. Platelets play a critical role in the pathogenesis of atherosclerosis and cardiovascular disease and, hence, it is possible that the cardiovascular effects of estrogens are mediated, at least in part, through inhibition of illicit platelet activation. The aim of this study was to examine the effects of sex steroids on adenosine diphosphate (ADP)-induced platelet aggregation and adenosine triphosphate (ATP) release in vitro in postmenopausal women. In addition, the effects of antiestrogens [4-hydroxy tamoxifen (4-OHT) and ICI 182780] and antiprogestins (RU 486 and ZK 98299) were also investigated. Preincubation of platelet-rich plasma (PRP) with antiestrogens or antiprogestins did not alter subsequent platelet aggregation or ATP release in response to ADP. However, preincubation with 17β-estradiol (E2) significantly inhibited ADP-mediated platelet aggregation by a mean (±SEM) of 37% ± 6% (p = 0.02) and ATP release by 82% ± 6% (p = 0.03), an effect that was reversed by the addition of ICI 182780 or 4-OHT but not RU 486 and ZK 98299. Although the progestin medroxyprogesterone acetate (MPA) also significantly inhibited platelet aggregation (by 28% ± 5%, p = 0.02) and ATP release (by 63% ± 9%, p = 0.02), this inhibition was not reversed by the addition of antiprogestins or antiestrogens. These data show that sex steroids can modulate platelet function in vitro. Furthermore, as platelets are devoid of nuclear components, these findings indicate that estrogens may regulate platelet function through binding to a non-nuclear receptor with ligand-binding properties similar or identical to the wild-type receptor. By contrast, MPA appears to exert its effect through a mechanism that does not involve binding to the “classical” progesterone receptor.

Inhibition of steroid sulphatase activity in endometriotic implants by 667 COUMATE: a potential new therapy

BACKGROUND

Local biosynthesis of estrogens is thought to be important for the maintenance and growth of endometriotic implants. In addition to the formation of estrogen via the aromatase pathway, steroid sulphatase (STS), which is responsible for the hydrolysis of estrogen sulphates, may be an important source of estrogens in endometriosis.

METHODS

Eutopic and ectopic endometrial samples from 14 women with minimal or mild (MM) endometriosis and from 13 women with moderate to severe (MS) endometriosis were analysed for aromatase and STS activities.

RESULTS

Aromatase and STS activity were detected in all samples. STS enzyme activity in both eutopic and ectopic endometrium was considerably higher and less variable than aromatase activity. Moreover, STS, but not aromatase, activity in endometriotic implants correlated with the severity of the disease (mean +/- SEM: 203 +/- 38 nmol/4 h/g wet weight tissue in MM disease versus 423 +/- 44 nmol/4 h/g wet weight tissue in MS endometriosis, P < 0.001). The STS inhibitor 667 COUMATE almost completely blocked STS activity (>99%) in both eutopic and ectopic tissues.

CONCLUSIONS

The high levels of STS activity detected in ectopic endometrium and the correlation with severity of disease suggest that STS inhibitors could be useful for the treatment of endometriosis.

Cyclic AMP and progesterone receptor cross-talk in human endometrium: a decidualizing affair

During the menstrual cycle, the ovarian hormones oestradiol and progesterone control the ordered growth and differentiation of uterine cells. This remodelling process is critical for implantation of the developing embryo, the formation of the placenta, and maintenance of pregnancy. Failure of uterine tIssues to respond appropriately to ovarian hormone signalling results in defective placentation, associated with a spectrum of pregnancy disorders such as recurrent miscarriages and preeclampsia. These obstetrical disorders are a major cause of maternal and perinatal morbidity and mortality. Progesterone exerts its action on target cells, at least in part, through binding to the progesterone receptor (PR), a member of the steroid/thyroid hormone receptor superfamily of ligand-activated transcription factors. The mechanism by which progesterone controls the differentiation of human endometrial stromal cells, a process termed decidualization, in the secretory phase of the menstrual cycle is not well understood. Emerging evidence indicates that locally expressed factors and activation of the cAMP second messenger pathway integrate hormonal inputs and confer cellular specificity to progesterone action through the induction of diverse transcription factors capable of modulating PR function.

Regulation of platelet aggregation and adenosine triphosphate release in vitro by 17beta-estradiol and medroxyprogesterone acetate in postmenopausal women

Clinical studies have suggested that hormone replacement therapy (HRT) may reduce the risk of coronary heart disease in postmenopausal women. Although progestins are commonly added to HRT preparations for uteroprotection, the perceived beneficial cardiovascular effects of HRT are thought to be mediated predominantly by the estrogen component. Platelets play a critical role in the pathogenesis of atherosclerosis and cardiovascular disease and, hence, it is possible that the cardiovascular effects of estrogens are mediated, at least in part, through inhibition of illicit platelet activation. The aim of this study was to examine the effects of sex steroids on adenosine diphosphate (ADP)-induced platelet aggregation and adenosine triphosphate (ATP) release in vitro in postmenopausal women. In addition, the effects of antiestrogens 14-hydroxy tamoxifen (4-OHT) and ICI 182780] and antiprogestins (RU 486 and ZK 98299) were also investigated. Preincubation of platelet-rich plasma (PRP) with antiestrogens or antiprogestins did not alter subsequent platelet aggregation or ATP release in response to ADP. However, preincubation with 17beta-estradiol (E2) significantly inhibited ADP-mediated platelet aggregation by a mean (+/-SEM) of 37%+/-6% (p = 0.02) and ATP release by 82%+/-6% (p = 0.03), an effect that was reversed by the addition of ICI 182780 or 4-OHT but not RU 486 and ZK 98299. Although the progestin medroxyprogesterone acetate (MPA) also significantly inhibited platelet aggregation (by 28%+/-5%, p = 0.02) and ATP release (by 63%+/-9%, p = 0.02), this inhibition was not reversed by the addition of antiprogestins or antiestrogens. These data show that sex steroids can modulate platelet function in vitro. Furthermore, as platelets are devoid of nuclear components, these findings indicate that estrogens may regulate platelet function through binding to a non-nuclear receptor with ligand-binding properties similar or identical to the wild-type receptor. By contrast, MPA appears to exert its effect through a mechanism that does not involve binding to the "classical" progesterone receptor.

Conservative laparoscopic treatment of ectopic pregnancies using the CO2-laser

OBJECTIVE

To assess the feasibility of CO2-laser-endoscopic surgical treatment for large and/or ruptured ectopic pregnancies, and to compare the results with those of microsurgical salpingotomy.

DESIGN

A retrospective review of all women treated for an ectopic pregnancy during a 6-year period, 1984-1989. During 1988 and 1989 treatment was randomized by the day of admission, depending only upon the surgeon in charge, some performing a linear salpingotomy (n = 42) and some a CO2-laser laparoscopy (n = 34) in all women haemodynamically stable.

SETTING

Department of Obstetrics and Gynaecology, University Hospital Gasthuisberg, Leuven.

SUBJECTS

135 women with ectopic pregnancies of whom 76 were included in the randomized series between 1988 and 1989. Overall 11 were treated by pelvic lavage, 78 by laparotomy and 46 by laparoscopic procedures.

MAIN OUTCOME MEASURES

Postoperative complications, duration of hospital stay. Cumulative pregnancy rates after the procedures.

RESULTS

The two groups of women analysed in the randomized series were comparable for duration of amenorrhoea, diameter of the ectopic pregnancy and prevalence of 'ruptured' ectopics, but the duration of stay in hospital was much shorter (mean 2.9, SD 1.8 days) for the 34 women treated by laparoscopy than for the 42 women treated by laparotomy (mean 6.8, SD 1.6 days). The postoperative cumulative pregnancy rate was higher in nulliparous women with a history of infertility or pelvic inflammatory disease (PID), when treated with CO2-laser-laparoscopy (P = 0.009). The recurrency rate was low (less than 5% in both groups). Overall in the women treated by laparotomy, postoperative cumulative pregnancy rates were lower following excision or adnexectomy than after a microsurgical linear salpingotomy (P = 0.01). Four women treated by laparoscopy required a second procedure.

CONCLUSION

Endoscopic treatment of large and/or ruptured ectopic pregnancies is feasible and resulted in a shorter hospital stay and, in nulliparous women with a history of PID or infertility, in higher cumulative pregnancy rates, than after microsurgical salpingotomies.