Carolien M. Boomsma

Endometrial secretion analysis identifies a cytokine profile predictive of pregnancy in IVF

BACKGROUND The study of human endometrial-embryonic interactions is complicated by the disruptive impact of endometrial sample collection on the process of implantation itself. Endometrial secretion analysis is a novel technique, non-disruptive to implantation. The primary aim of this prospective cohort study was to explore whether a cytokine profile predictive of implantation and clinical pregnancy can be identified in endometrial secretions aspirated immediately prior to embryo transfer following IVF. METHODS Endometrial secretions, aspirated immediately prior to embryo transfer from 210 women undergoing IVF, were analyzed using a multiplex immunoassay for 17 soluble regulators of implantation, namely interleukin (IL)-1beta, IL-5, IL-6, IL-10, IL-12, IL-15, IL-17, IL-18, tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, macrophage migration inhibitory factor, eotaxin, IFN-gamma-inducible 10 kDa protein (IP-10), monocyte chemo-attractant protein-1 (MCP-1), Dickkopf homolog 1, heparin-binding epidermal growth factor and vascular endothelial growth factor (VEGF). In order to detect implantation, daily urine samples were collected after embryo transfer, and human Chorionic Gonadotropin (hCG) concentrations were analyzed by an immunoassay. RESULTS Multivariable logistic regression analysis revealed significant associations (negative and positive association, respectively) between MCP-1 (P = 0.005) and IP-10 (P = 0.037) levels and implantation, and between IL-1beta (P = 0.047) and TNF-alpha (P = 0.023) levels and clinical pregnancy. The predictive value for pregnancy of IL-1beta and TNF-alpha was observed to be equivalent and additive to that of embryo quality. CONCLUSIONS Endometrial secretion cytokine profiling offers a novel, non-disruptive approach to study the role of the endometrium in human embryo implantation and identifies a profile which appears to be conducive to clinical pregnancy. CLINICAL TRIAL REGISTRATION www.clinicaltrials.gov (nCT00264992).

Pregnancy complications in women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. There is an increasing body of evidence indicating that PCOS may have significant implications for pregnancy outcomes and long-term health of a woman and her offspring. Whether or not PCOS itself or the symptoms that coincide with PCOS, like obesity and fertility treatment, are responsible for these increased risks is a continuing matter of debate. Miscarriage rates among women with PCOS are believed to be increased compared with normal fertile women, although supporting evidence is limited. Pregnant women with PCOS experience a higher incidence of perinatal morbidity from gestational diabetes, pregnancy-induced hypertension, and preeclampsia. Their babies are at an increased risk of neonatal complications, such as preterm birth and admission at a neonatal intensive care unit. Pre-pregnancy, antenatal, and intrapartum care should be aimed at reducing these risks. The use of insulin sensitizing drugs to decrease hyperinsulinemic insulin resistance has been proposed during pregnancy to reduce the risk of developing preeclampsia or gestational diabetes. Although metformin appears to be safe, there are too few data from prospective, randomized controlled trials to support treatment during pregnancy.

Uterine Selection of Human Embryos at Implantation

Human embryos frequently harbor large-scale complex chromosomal errors that impede normal development. Affected embryos may fail to implant although many first breach the endometrial epithelium and embed in the decidualizing stroma before being rejected via mechanisms that are poorly understood. Here we show that developmentally impaired human embryos elicit an endoplasmic stress response in human decidual cells. A stress response was also evident upon in vivo exposure of mouse uteri to culture medium conditioned by low-quality human embryos. By contrast, signals emanating from developmentally competent embryos activated a focused gene network enriched in metabolic enzymes and implantation factors. We further show that trypsin, a serine protease released by pre-implantation embryos, elicits Ca2+ signaling in endometrial epithelial cells. Competent human embryos triggered short-lived oscillatory Ca2+ fluxes whereas low-quality embryos caused a heightened and prolonged Ca2+ response. Thus, distinct positive and negative mechanisms contribute to active selection of human embryos at implantation.

Cytokine profiling in endometrial secretions: A non-invasive window on endometrial receptivity

Investigation of human embryo implantation requires a non-disruptive means of studying the endometrium during the window of implantation. This study describes a novel approach of cytokine profiling in endometrial secretions. Endometrial secretions aspirated prior to embryo transfer from 210 women undergoing IVF or intracytoplasmic sperm injection were analysed by a multiplex immunoassay. Ten mediators [interleukin (IL)-1beta, IL-6, IL-12, IL-18, tumour necrosis factor-alpha, macrophage migration inhibitory factor, eotaxin, monocyte chemotactic protein-1, interferon-gamma inducible protein-10, vascular endothelial growth factor] were detectable in 90-100% of the samples. Heparin-binding epidermal growth factor, IL-5, IL-17, IL-10, Dickkopf homologue-1 and IL-15 were detected in 23-76%, whereas interferon-gamma was not detectable in any of the samples. To assess possible contamination of samples, cervical mucus was also aspirated for comparative analysis in 22 women. The endometrial cytokine profile differed significantly from cervical mucus. Pregnancy rates of the study participants who underwent endometrial secretion aspiration were compared with 210 controls matched for important prognostic variables; no significant differences were found. In conclusion, cytokine profiling in endometrial secretion offers an objective, non-disruptive means of analysing the in-vivo milieu encountered by the embryo and offers a new and potentially valuable approach to studying the endometrial factor in human embryo implantation.

Ovarian stimulation for in vitro fertilization alters the intrauterine cytokine, chemokine, and growth factor milieu encountered by the embryo

OBJECTIVE To elucidate the impact of ovarian stimulation on the intrauterine milieu represented by the cytokine, chemokine, and growth factor profile in endometrial secretions aspirated before embryo transfer. DESIGN Prospective cohort study. SETTING Fertility center in tertiary referral university hospital. PATIENT(S) Forty-two patients undergoing ovarian stimulation with GnRH analogues were recruited. They participated in both a natural and an ovarian-stimulated cycle for within patient comparisons. INTERVENTION(S) Endometrial secretion aspiration was performed immediately before embryo transfer. MAIN OUTCOME MEASURE(S) The concentrations of 17 mediators known to be involved in human embryo implantation were assessed by multiplex immunoassay. RESULT(S) After correction for multiple testing, significantly higher concentrations of interleukin (IL)-1β, IL-5, IL-10, IL-12, IL-17, tumor necrosis factor (TNF)-α, heparin-binding epidermal growth factor (HbEGF), eotaxin, and dickkopf homologue-1 were present in endometrial secretions obtained in stimulated compared with natural cycles. CONCLUSION(S) Endometrial secretion analysis provides a novel means of investigating the effect of ovarian stimulation on the intrauterine milieu. The in vivo milieu encountered by the embryo after transfer is significantly altered by ovarian stimulation.

An endometrial gene expression signature accurately predicts recurrent implantation failure after IVF

The primary limiting factor for effective IVF treatment is successful embryo implantation. Recurrent implantation failure (RIF) is a condition whereby couples fail to achieve pregnancy despite consecutive embryo transfers. Here we describe the collection of gene expression profiles from mid-luteal phase endometrial biopsies (n = 115) from women experiencing RIF and healthy controls. Using a signature discovery set (n = 81) we identify a signature containing 303 genes predictive of RIF. Independent validation in 34 samples shows that the gene signature predicts RIF with 100% positive predictive value (PPV). The strength of the RIF associated expression signature also stratifies RIF patients into distinct groups with different subsequent implantation success rates. Exploration of the expression changes suggests that RIF is primarily associated with reduced cellular proliferation. The gene signature will be of value in counselling and guiding further treatment of women who fail to conceive upon IVF and suggests new avenues for developing intervention.

What can the clinician do to improve implantation

Implantation is a complicated process that requires the orchestration of a series of events involving both the embryo and the endometrium. Even with the transfer of high quality embryos, implantation rates remain relatively low. The growing tendency towards transferring fewer embryos provides further incentives to improve implantation rates. In this article, the various clinical strategies employed to increase the chance of implantation are reviewed. Embryo transfer technique is a critical step in assisted reproductive technology cycles. Recent studies have shown significant improvements in clinical pregnancy rates resulting from careful embryo transfer technique, appropriate catheter type and placing for embryo transfer. Increasingly, adjuvant pharmaceutical therapies are also being applied with the aim of improving embryo implantation. However, the evidence for their efficacy and safety is limited. Recent evidence suggests that adoption of milder ovarian stimulation regimens may provide a more effective clinical approach to improving implantation, since beneficial effects have been shown for both endometrial receptivity and embryo quality.

Does glucocorticoid therapy in the peri-implantation period have an impact on IVF outcomes?

Purpose of review Failure of the embryo to implant remains the major limiting step in assisted reproductive techniques success rates. The existing evidence supports a possible role of glucocorticoids in improving the intrauterine environment and therefore embryo implantation. The present study aims to summarize the available evidence and make recommendations about the use of glucocorticoids. Recent findings A recent meta-analysis on glucocorticoids to improve embryo implantation showed no beneficial effect in the routine IVF/intracytoplasmic sperm injection population, although a subgroup analysis of women undergoing IVF did show a borderline improvement in pregnancy rates. Studies on women with autoantibodies or treatment cycles in which assisted hatching is performed have also indicated a benefit from glucocorticoid cotreatment. No significant improvement in pregnancy rates, however, has been demonstrated in women with recurrent implantation failure in whom assisted hatching is performed in combination with glucocorticoids. Conflicting results have been reported on the use of glucocorticoids to improve the ovarian response. Summary Although evidence to support the empirical use of glucocorticoids to improve implantation is insufficient, these may be beneficial in specific patient groups. More studies are required to confirm the efficacy and safety of adjuvant glucocorticoid therapy, and they should only be empirically used in the context of randomized controlled trials.

Is bacterial vaginosis associated with a pro-inflammatory cytokine profile in endometrial secretions of women undergoing IVF?

The objective of this prospective cohort study was to elucidate whether bacterial vaginosis (BV) is associated with a pro-inflammatory endometrial secretion cytokine profile and whether there is a relationship between BV and the concentrations of a number of key regulatory cytokines, chemokines and growth factors. A total of 198 women undergoing IVF treatment were included. Prior to embryo transfer, participants underwent screening for BV according to Nugent criteria by a Gram-stained cervical smear. The concentrations of 17 soluble mediators of human implantation were measured by multiplex immunoassay in endometrial secretions aspirated prior to embryo transfer. Seventeen (8.6%) women had BV (Nugent score >6). Multivariable logistic regression showed a significant positive association between interleukin-beta and the presence of BV (P=0.011; Nugent score >6 versus 6) and a significant negative association between eotaxin and BV (P=0.003). No significant differences were found in the ratios of distinct pro- and anti-inflammatory cytokines in endometrial secretions from women with or without BV. In conclusion, BV is associated with higher concentrations of interleukin-beta in endometrial secretions compared with women without BV. However, no distinct difference in pro- and anti-inflammatory profiles is present. An effect on endometrial receptivity is unlikely.

Development of nanoelectrospray high resolution isotope dilution mass spectrometry for targeted quantitative analysis of urinary metabolites: application to population profiling and clinical studies

An automated chip-based electrospray platform was used to develop a high-throughput nanoelectrospray high resolution mass spectrometry (nESI-HRMS) method for multiplexed parallel untargeted and targeted quantitative metabolic analysis of urine samples. The method was demonstrated to be suitable for metabolic analysis of large sample numbers and can be applied to large-scale epidemiological and stratified medicine studies. The method requires a small amount of sample (5 μL of injectable volume containing 250 nL of original sample), and the analysis time for each sample is three minutes per sample to acquire data in both negative and positive ion modes. Identification of metabolites was based on the high resolution accurate mass and tandem mass spectrometry using authentic standards. The method was validated for 8 targeted metabolites and was shown to be precise and accurate. The mean accuracy of individual measurements being 106% and the intra- and inter-day precision (expressed as relative standard deviations) were 9% and 14%, respectively. Selected metabolites were quantified by standard addition calibration using the stable isotope labelled internal standards in a pooled urine sample, to account for any matrix effect. The multiple point standard addition calibration curves yielded correlation coefficients greater than 0.99, and the linear dynamic range was more than three orders of magnitude. As a proof-of-concept the developed method was applied for targeted quantitative analysis of a set of 101 urine samples obtained from female participants with different pregnancy outcomes. In addition to the specifically targeted metabolites, several other metabolites were quantified relative to the internal standards. Based on the calculated concentrations, some metabolites showed significant differences according to different pregnancy outcomes. The acquired high resolution full-scan data were used for further untargeted fingerprinting and improved the differentiation of urine samples based on pregnancy outcome.