Glycodelin in endometrial flushing fluid and endometrial biopsies from infertile and fertile women

The definition of unexplained infertility: A systematic review

BACKGROUND

There is no consensus on tests required to either diagnose unexplained infertility or use for research inclusion criteria. This leads to heterogeneity and bias affecting meta-analysis and best practice advice.

OBJECTIVES

This systematic review analyses the variability of inclusion criteria applied to couples with unexplained infertility. We propose standardised criteria for use both in future research studies and clinical diagnosis.

SEARCH STRATEGY

CINAHL and MEDLINE online databases were searched up to November 2022 for all published studies recruiting couples with unexplained infertility, available in full text in the English language.

DATA COLLECTION AND ANALYSIS

Data were collected in an Excel spreadsheet. Results were analysed per category and methodology or reference range.

MAIN RESULTS

Of 375 relevant studies, only 258 defined their inclusion criteria. The most commonly applied inclusion criteria were semen analysis, tubal patency and assessment of ovulation in 220 (85%), 232 (90%), 205 (79.5%) respectively. Only 87/220 (39.5%) studies reporting semen analysis used the World Health Organization (WHO) limits. Tubal patency was accepted if bilateral in 145/232 (62.5%) and if unilateral in 24/232 (10.3%). Ovulation was assessed using mid-luteal serum progesterone in 115/205 (56.1%) and by a history of regular cycles in 87/205 (42.4%). Other criteria, including uterine cavity assessment and hormone profile, were applied in less than 50% of included studies.

CONCLUSIONS

This review highlights the heterogeneity among studied populations with unexplained infertility. Development and application of internationally accepted criteria will improve the quality of research and future clinical care.

Non-Invasive and Mechanism-Based Molecular Assessment of Endometrial Receptivity During the Window of Implantation: Current Concepts and Future Prospective Testing Directions

Suboptimal endometrial receptivity and altered embryo-endometrial crosstalk account for approximately two-thirds of human implantation failures. Current tests of the window of implantation, such as endometrial thickness measurements and the endometrial receptivity assay, do not consistently improve clinical outcomes as measured by live birth rates. Understanding the mechanisms regulating the endometrial receptivity during the window of implantation is a critical step toward developing clinically meaningful tests. In this narrative review, the available literature is evaluated regarding mechanisms that regulate the endometrial receptivity during the window of implantation and the current tests developed. Overall, both animal and human studies point to five possible and interrelated mechanisms regulating the endometrial window of implantation: suitable synchrony between endometrial cells, adequate synchrony between the endometrium and the embryo, standard progesterone signaling and endometrial responses to progesterone, silent genetic variations, and typical morphological characteristics of the endometrial glands. The biological basis of current clinical markers or tests of window of implantation is poor. Future studies to elucidate the mechanisms shaping the window of implantation and to investigate the potential markers based on these mechanisms are required. In addition, molecular testing of the endometrium at single-cell resolution should be an initial step toward developing clinically meaningful tests for the optimal window of implantation. As understanding of the optimal window of implantation continues to evolve, one can envision the future development of non-invasive, mechanism-based testing of the window of implantation.

Mucosal biomarkers for endometrial receptivity: A promising yet underexplored aspect of reproductive medicine

Annually, approximately 2 million assisted reproductive technology (ART) procedures are performed worldwide, of which, only ~25% lead to successful delivery. There are two major factors contributing to successful implantation: embryo quality and endometrial receptivity (ER). Although embryo quality might be assessed through morphological and genetic testing, no clinically approved techniques are available to evaluate ER. Mucus in different parts of the female reproductive tract contains many cytokines, chemokines, growth factors, and nucleic acids, which influence and reflect various implantation-related processes. Therefore, the aim of the present review was to summarize available data regarding noninvasively obtained mucosal biomarkers for ER and to investigate their ability to predict the outcome of ART procedures. A broad literature search was performed to define studies related to noninvasive ER assessments. More than 50 biomarkers detectable in endometrial fluid, embryo transfer cannula leftover cells and mucus, menstrual blood, cervicovaginal washings are discussed herein. The remarkable methodological heterogeneity of the reviewed studies complicates the comparison of their results. Nevertheless, certain promising analytical targets may already be identified, such as urocortin, activin A, IL-1β, TNF-α, IP-10, MCP-1, and several oxidative stress biomarkers. The present review contains a collection of currently available mucosal biomarker-related data, which may provide insights for future studies.Abbreviations: ART: assisted reproductive technology; ER: endometrial receptivity; IVF: in vitro fertilization; ICSI: intracytoplasmic sperm injection; IUI: intrauterine insemination; MeSH: Medical Subject Headings; hDP 200: human decidua-associated protein 200; ET: embryo transfer; IL-18: Interleukin-18; LRG: leucine-rich α2-glycoprotein; ROC: receiver operating characteristic; AUC: area under the ROC-curve; LH: luteinizing hormone; LIF: leukemia inhibitory factor; TNF-α: tumor necrosis factor alpha; IFN-γ: interferon γ; MCP-1: monocyte chemoattractant protein-1; VEGF: vascular endothelial growth factor; SOD: superoxide dismutase; CAT: catalase; LPO: lipid peroxidation; TTG: total thiol groups; TAP: total antioxidant power; CE: chronic endometritis.

Conventional and modern markers of endometrial receptivity: a systematic review and meta-analysis

BACKGROUND

Early reproductive failure is the most common complication of pregnancy with only 30% of conceptions reaching live birth. Establishing a successful pregnancy depends upon implantation, a complex process involving interactions between the endometrium and the blastocyst. It is estimated that embryos account for one-third of implantation failures, while suboptimal endometrial receptivity and altered embryo-endometrial dialogue are responsible for the remaining two-thirds. Endometrial receptivity has been the focus of extensive research for over 80 years, leading to an indepth understanding of the processes associated with embryo-endometrial cross-talk and implantation. However, little progress has been achieved to translate this understanding into clinically meaningful prognostic tests and treatments for suboptimal endometrial receptivity.

OBJECTIVE AND RATIONALE

The objective of this systematic review was to examine the evidence from observational studies supporting the use of endometrial receptivity markers as prognostic factors for pregnancy outcome in women wishing to conceive, in order to aid clinicians in choosing the most useful marker in clinical practice and for informing further research.

SEARCH METHODS

The review protocol was registered with PROSPERO (CRD42017077891). MEDLINE and Embase were searched for observational studies published from inception until 26 February 2018. We included studies that measured potential markers of endometrial receptivity prior to pregnancy attempts and reported the subsequent pregnancy outcomes. We performed association and accuracy analyses using clinical pregnancy as an outcome to reflect the presence of receptive endometrium. The Newcastle-Ottawa scale for observational studies was employed to assess the quality of the included studies.

OUTCOMES

We included 163 studies (88 834 women) of moderate overall quality in the narrative synthesis, out of which 96 were included in the meta-analyses. Studies reported on various endometrial receptivity markers evaluated by ultrasound, endometrial biopsy, endometrial fluid aspirate and hysteroscopy in the context of natural conception, IUI and IVF. Associations were identified between clinical pregnancy and various endometrial receptivity markers (endometrial thickness, endometrial pattern, Doppler indices, endometrial wave-like activity and various molecules); however, their poor ability to predict clinical pregnancy prevents them from being used in clinical practice. Results from several modern molecular tests are promising and further data are awaited.

WIDER IMPLICATIONS

The post-test probabilities from our analyses may be used in clinical practice to manage couples' expectations during fertility treatments (IUI and IVF). Conventionally, endometrial receptivity is seen as a dichotomous outcome (present or absent), but we propose that various levels of endometrial receptivity exist within the window of implantation. For instance, different transcriptomic signatures could represent varying levels of endometrial receptivity, which can be linked to different pregnancy outcomes. Many studies reported the means of a particular biomarker in those who achieved a pregnancy compared with those who did not. However, extreme values of a biomarker (as opposite to the means) may have significant prognostic and diagnostic implications that are not captured in the means. Therefore, we suggest reporting the outcomes by categories of biomarker levels rather than reporting means of biomarker levels within clinical outcome groups.

Analysis of Glycodelin Levels Before and After Hysteroscopic Polypectomy in Infertile Patients

Glycodelin (or placental protein 14) is a glycoprotein located in the glandular and thin epithelium of the endometrium. It is considered an important factor in the implantation process, and its traces can be found in elevated concentrations in the uterine flushing obtained at the time of implantation, while in the proliferative phase of the cycle, its levels are low. A certain concentration has been found to inhibit the binding of spermatozoids to the zona pellucida of the oocites therefore, it effects conception. It has a role in angiogenesis and is in high concentrations in the tissues of both benign and malignant gynaecological tumours.

The aim of this study is to analyse and display the glycodelin level changes before and after hysteroscopic polypectomy in infertile patients in the uterine flushing fluid and serum. This survey covers 80 infertile patients, who were divided into two groups. The first group, the experimental group, consisted of 50 infertile patients with endometrial polyps, and a control group of 30 infertile patients without endometrial polyps was also included.

The results primarily indicate the existence of changes in glycodelin levels preoperatively in the flushing and venous blood in infertile patients with endometrial polyps compared with the levels after surgery. In the control group of patients, no significant change in the glycodelin levels was detected in the flushing and venous blood. When comparing these two groups, statistically significant differences in the glycodelin levels in the flushing and venous blood were noted. We conclude that the presence of endometrial polyps in the cavum uteri affects the increase in the glycodelin concentration in the flushing fluid and in the plasma. Increased glycodelin concentrations complicate fertilization and implantation.

Combinatorial effects of quercetin and sex-steroids on fluid and electrolytes' (Na+, Cl-, HCO3-) secretory mechanisms in the uterus of ovariectomised female Sprague-Dawley rats

Dysregulation of uterine fluid environment could impair successful reproduction and this could be due to the effect of environmental estrogens. Therefore, in this study, effect of quercetin, an environmental estrogen on uterine fluid and electrolytes concentrations were investigated under sex-steroid influence. Ovariectomised adult female Sprague-Dawley rats were given 10, 50 or 100mg/kg/day quercetin subcutaneously with 17-β estradiol (E) for seven days or three days E, then three days E plus progesterone (P) (E+P) treatment. Uterine fluid secretion rate, Na⁺, Cl^- and HCO₃^- concentrations were determined by in-vivo perfusion. Following sacrifice, uteri were harvested and levels of the proteins of interest were identified by Western blotting and Realtime PCR. Distribution of these proteins in the uterus was observed by immunofluorescence. Levels of uterine cAMP were measured by enzyme-linked immunoassay (EIA). Administration of quercetin at increasing doses increased uterine fluid secretion rate, Na⁺, Cl^- and HCO₃^- concentrations, but to the levels lesser than that of E. In concordant, levels of CFTR, SLC4A4, ENaC (α, β and γ), Na⁺/K⁺-ATPase, GPα/β, AC and cAMP in the uterus increased following increased in the doses of quercetin. Co-administration of quercetin with E caused uterine fluid secretion rate, Na⁺, Cl^- and HCO₃^- concentrations to decrease. In concordant, uterine CFTR, SLC26A6, SLC4A4, ENaC (α, β and γ), Na⁺/K⁺-ATPase, GPα/β, AC and cAMP decreased. Greatest effects were observed following co-administration of 10mg/kg/day quercetin with E. Co-administration of quercetin with E+P caused uterine fluid Na⁺ and HCO₃^- concentrations to increase but no changes in fluid secretion rate and Cl^- concentration were observed. Co-administration of high dose quercetin (100 mg/kg/day) with E+P caused uterine CFTR, SLC26A6, AC, GPα/β and ENaC (α, β and γ) to increase. Quercetin-induced changes in the uterine fluid secretion rate and electrolytes concentrations could potentially affect the uterine reproductive functions under female sex-steroid influence.

Role of Mucin 1 and Glycodelin A in recurrent implantation failure

OBJECTIVE

To evaluate and compare the levels of Mucin 1 (MUC-1) and Glycodelin A (GdA) in precisely timed endometrial biopsies and blood samples taken from women with recurrent implantation failure, and women with proven fertility, in a control group.

DESIGN

Molecular studies in human blood and tissue.

SETTING

University hospital.

PATIENT(S)

Women with recurrent implantation failure and women with proven fertility.

INTERVENTION(S)

Primary endometrial cells and blood samples during the implantation "window" (between day 7 and day 9 after the surge in luteinizing hormone).

MAIN OUTCOME MEASURE(S)

Expression of MUC-1 and GdA in the human endometrium and in blood during the implantation window were analyzed by enzyme-linked immunosorbent assay. Additionally, MUC-1 and GdA levels in tissue were analyzed by western blot during the same period.

RESULT(S)

Both blood and tissue measurements of MUC-1 and GdA were significantly lower in women with recurrent implantation failure than in fertile women during the implantation window. In addition, we found a highly significant correlation between blood vs. tissue measurements of both MUC-1 and GdA.

CONCLUSION(S)

The present study reveals that blood and tissue levels of MUC-1 and GdA are much lower in women with RIF, compared with those in fertile women. Receptivity can be evaluated with noninvasive blood sampling, rather than more-invasive endometrium sampling, as the blood and tissue measurements of MUC-1 and GdA are correlated.

Venous intravasation as a complication and potential pitfall during hysterosalpingography: re-emerging study with a novel classification

OBJECTIVES

Presently, hysterosalpingography (HSG) is used as a means to evaluate women with infertility and repetitive pregnancy loss. Venous intravasation is a complication and potential pitfall during HSG and analogous procedures including hysteroscopy. The aim of our study was to assess the venous intravasation and to obtain critical information for more secure and more accurate procedures. In particular, the primary goal of the present study was to compare HSG without and with intravasation to identify differences seen on HSG and to assess the predisposing factors of intravasation. The secondary goal was to describe clinical- and imaging-based novel classification of intravasation.

MATERIALS AND METHODS

This study included a patient cohort of 569 patients who underwent HSG between 2008 and 2011 at our center in the absence (control group) or presence (study group) of intravasation. Intravasation classified from level 0 (no intravasation) to level 3 (severe intravasation) was compared with preprocedural (demographic and clinical) and procedural (HSG) data. Data were analyzed using Statistical Package for Social Sciences (SPSS) statistical software.

RESULTS

Of the 569 patients undergoing HSG, 528 showed no intravasation and 41 (7.2%) patients showed intravasation when associated with preprocedural (leukocytes, menometrorrhagia, secondary infertility, ectopic pregnancy, abortus, polycystic ovaries, endometriosis, and interventions) and procedural (pain, scheduling, endometrial-uterine nature, and spillage) parameters. Moreover, intravasation was lower in women with smooth endometrium, triangular uterus, and homogeneous peritoneal spillage. No association was found between age, tubal patency, increased pressure, and intravasation.

CONCLUSIONS

Using a novel classification method, intravasation can be observed in women during HSG and associates with preprocedural and procedural predisposing factors in subsumed conditions. This classification method will be useful for improving the efficiency and accuracy of HSG and related procedures by minimization of severe complications caused by intravasation.