Androgen-induced alterations in endometrial proteins crucial in recurrent miscarriages

[Analysis of Risk Factors for Recurrent Pregnancy Loss in Patients Undergoing in vitro Fertilization-Embryo Transfer]

Objective

Recurrent pregnancy loss (RPL) presents a formidable challenge for individuals undergoing in vitro fertilization-embryo transfer (IVF-ET), forming both a clinical dilemma and a focal point for scientific inquiry. This study endeavors to investigate the intricate interplay between clinical features, such as age, body mass index (BMI), and waist-to-hip ratio (WHR), and routine laboratory parameters, including sex hormones, blood composition, liver and thyroid functions, thyroid antibodies, and coagulation indicators, in RPL patients undergoing IVF-ET. By meticulously analyzing these variables, we aim to uncover the latent risk factors predisposing individuals to RPL. Identifying potential factors such as advanced maternal age, obesity, and insulin resistance will provide clinicians with vital insights and empirical evidence to strengthen preventive strategies aimed at reducing miscarriage recurrence.

Methods

This retrospective case-controlled study included RPL patients who underwent IVF-ET treatment at Sun Yat-sen Memorial Hospital, Sun Yat-sen University, between January 2012 and March 2021 as the case cohort, compared with women receiving assisted reproductive treatment due to male infertility as the control cohort. The fasting peripheral blood was collected 5 days before the first menstrual cycle at least 12 weeks after the last abortion. The clinical characteristics and relevant laboratory indexes of the two groups were compared. Employing both univariate and multivariate logistic regression analyses, we sought to unearth potential high-risk factors underlying RPL. Additionally, a linear trend analysis was conducted to assess the linear relationship between total testosterone (TT) levels and the number of miscarriages.

Results

In contrast to the control cohort, the RPL cohort exhibited significant increases in age, BMI, and WHR (P<0.05). Notably, TT levels were markedly lower in the RPL cohort (P=0.022), while no significant differences were observed between the two groups concerning basal follicle-stimulating hormone, luteinizing hormone, estradiol, progesterone, prolactin levels, and anti-Müllerian hormone levels (P>0.05). Moreover, fasting insulin (FINS) levels and HOMA-IR index were notably elevated in the RPL cohort relative to the control cohort (P<0.001), although no significant differences were observed in fasting blood glucose levels (P>0.05). Furthermore, the neutrophil (NEU) count and NEU-to-lymphocyte ratio were notably higher in the RPL cohort (P<0.01). Univariate logistic regression analysis identified several factors, including age≥35 years old, BMI≥25 kg/m2, WHR>0.8, FINS>10 mU/L, HOMA-IR>2.14, NEU count>6.3×109 L－1, and an elevated NEU/lymphocyte ratio (NLR), as significantly increasing the risk of RPL (P<0.05). Although TT levels were within the normal range for both cohorts, higher TT levels were associated with a diminished RPL risk (odds ratio [OR]=0.67, 95% confidence interval [CI]: 0.510-0.890, P=0.005). After adjustments for confounding factors, age≥35 years old (OR=1.91, 95% CI: 1.06-3.43), WHR>0.8 (OR=2.30, 95% CI: 1.26-4.19), and FINS>10 mU/L (OR=4.50, 95% CI: 1.30-15.56) emerged as potent risk factors for RPL (P<0.05). Conversely, higher TT levels were associated with a reduced RPL risk (OR=0.59, 95% CI: 0.38-0.93, P=0.023). Furthermore, the linear trend analysis unveiled a discernible linear association between TT levels and the number of miscarriages (P trend=0.003), indicating a declining trend in TT levels with escalating miscarriage occurrences.

Conclusion

In patients undergoing IVF-ET, advanced maternal age, lower TT levels, increased WHR, and elevated FINS levels emerged as potent risk factors for RPL. These findings provide clinicians with valuable insights and facilitate the identification of patients who are at high risks and the formulation of preventive strategies to reduce the recurrence of miscarriages.

Hyperandrogenism and Its Possible Effects on Endometrial Receptivity: A Review

Endometrial receptivity is a state of the endometrium defined by its readiness for embryo implantation. When the receptivity of the endometrium is impaired due to hyperandrogenism or androgen excess, this condition can lead to pregnancy loss or infertility. Hyperandrogenism encompasses a wide range of clinical manifestations, including polycystic ovary syndrome (PCOS), idiopathic hirsutism, hirsutism and hyperandrogaenemia, non-classical congenital adrenal hyperplasia, hyperandrogenism, insulin resistance, acanthosis nigricans (HAIR-AN), ovarian or adrenal androgen-secreting neoplasms, Cushing's syndrome, and hyperprolactinaemia. Recurrent miscarriages have been shown to be closely related to elevated testosterone levels, which alter the endometrial milieu so that it is less favourable for embryo implantation. There are mechanisms for endometrial receptivity that are affected by excess androgen. The HOXA gene, aVβ3 integrin, CDK signalling pathway, MECA-79, and MAGEA-11 were the genes and proteins affect endometrial receptivity in the presence of a hyperandrogenic state. In this review, we would like to explore the other manifestations of androgen excess focusing on causes other than PCOS and learn possible mechanisms of endometrial receptivity behind androgen excess leading to pregnancy loss or infertility.

Androgen signalling in the ovaries and endometrium

Currently, our understanding of hormonal regulation within the female reproductive system is largely based on our knowledge of estrogen and progesterone signalling. However, while the important functions of androgens in male physiology are well known, it is also recognized that androgens play critical roles in the female reproductive system. Further, androgen signalling is altered in a variety of gynaecological conditions, including endometriosis and polycystic ovary syndrome, indicative of regulatory roles in endometrial and ovarian function. Co-regulatory mechanisms exist between different androgens, estrogens, and progesterone, resulting in a complex network of steroid hormone interactions. Evidence from animal knockout studies, in vitro experiments, and human data indicate that androgen receptor expression is cell-specific and menstrual cycle stage-dependent, with important regulatory roles in the menstrual cycle, endometrial biology, and follicular development in the ovaries. This review will discuss the expression and co-regulatory interactions of androgen receptors, highlighting the complexity of the androgen signalling pathway in the endometrium and ovaries, and the synthesis of androgens from additional alternative pathways previously disregarded as male-specific. Moreover, it will illustrate the challenges faced when studying androgens in female biology, and the need for a more in-depth, integrative view of androgen metabolism and signalling in the female reproductive system.

Circ_0115118 regulates endometrial functions through the miR-138-1-3p/WDFY2 axis in patients with PCOS†

To investigate the expression profiles of circular RNAs (circRNAs) in the endometria of women with polycystic ovary syndrome (PCOS) and to explore the role of aberrant circ_0115118 expression in endometrial dysfunction in patients with PCOS. CircRNA microarray hybridization and bioinformatic analyses were performed to determine the expression patterns of circRNAs in the endometria of patients with or without PCOS, the expression of target circRNA was evaluated by real-time polymerase chain reaction (PCR). Cell counting kit-8 and Transwell assays were used to detect cellular proliferative, invasive, and migratory capacities. The influence of the circRNA on decidualization was explored by real-time PCR. Animal models were established to investigate the regulatory effect of the circRNA on embryo implantation. Downstream microRNAs and genes were predicted using bioinformatic websites and verified by dual-luciferase reporter assays, real-time PCR, and western blotting. In the endometria of patients with PCOS, there were 113 differentially expressed circRNAs in the secretory phase and 1119 differentially expressed circRNAs in the proliferative phase. The expression of circ_0115118 was significantly higher in endometrial stromal cells during the proliferative phase in patients with PCOS, leading to inhibition of cellular mobilization and embryo implantation. In addition, circ_0115118 exerted effects by sponging miR-138-1-3p, subsequently increasing the expression of WD repeat and FYVE domain-containing protein 2 (WDFY2). Circ_0115118 expression is dysregulated in the endometria of patients with PCOS and adversely affects endometrial function. Our findings reveal that circ_0115118 may be a potential therapeutic target to improve pregnancy outcomes in women with PCOS.

Abnormal Endometrial Receptivity and Oxidative Stress in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women of childbearing age. Individual heterogeneity is evident, and the prevalence rate ranges between 6 and 15% globally. The prevalence rate of PCOS in Chinese women of childbearing age is 5.6%. The main manifestations are infertility, sparse menstruation, irregular vaginal bleeding, long-term endometrial hyperplasia, and endometrial cancer. PCOS is often associated with hyperandrogenemia, insulin resistance, hyperinsulinemia, obesity, metabolic syndrome, and intestinal flora disorder. Although there have been many studies in the past, the underlying pathophysiological mechanism of the disease is still unclear. Studies have shown that PCOS diseases and related complications are closely related to local oxidative stress imbalance in the endometrium, leading to poor endometrial receptivity and effects on pregnancy. Previous reviews have mainly focused on the abnormal mechanism of ovarian oxidative stress in women with PCOS, while reviews on endometrial receptivity and oxidative stress are relatively insufficient. This study reviews the abnormal cellular and molecular mechanisms of oxidative stress due to comorbidities in women with PCOS, leading to a downregulation of endometrial receptivity.

Insight on Polyunsaturated Fatty Acids in Endometrial Receptivity

Endometrial receptivity plays a crucial role in fertilization as well as pregnancy outcome in patients faced with fertility challenges. The optimization of endometrial receptivity may help with normal implantation of the embryo, and endometrial receptivity may be affected by numerous factors. Recently, the role of lipids in pregnancy has been increasingly recognized. Fatty acids and their metabolites may be involved in all stages of pregnancy and play a role in supporting cell proliferation and development, participating in cell signaling and regulating cell function. Polyunsaturated fatty acids, in particular, are essential fatty acids for the human body that can affect the receptivity of the endometrium through in a variety of methods, such as producing prostaglandins, estrogen and progesterone, among others. Additionally, polyunsaturated fatty acids are also involved in immunity and the regulation of endometrial decidualization. Fatty acids are essential for fetal placental growth and development. The interrelationship of polyunsaturated fatty acids with these substances and how they may affect endometrial receptivity will be reviewed in this article.

Research progress of endometrial receptivity in patients with polycystic ovary syndrome: a systematic review

Polycystic ovary syndrome (PCOS) is a neuroendocrine heterogeneous disease that frequently occurs in women of reproductive age, causing serious damage to the fertility, quality of life, and physical and mental health of patients. The current studies have proved that satisfactory endometrial receptivity is one of the conditions that must be met during the process of spermatovum position, adhesion and invasion, as well as the subsequent blastocyst division and embryo development. Women with PCOS may suffer a series of pathological processes such as changes in the expression levels of hormones and related receptors, imbalances in the proportion of miscellaneous cytokines, insulin resistance, low-grade chronic inflammation and endometrial morphological changes, which will damage endometrial receptivity from various aspects and obstruct fertilized egg nidation and embryonic development, thus causing adverse reproductive health events including infertility and abortion. This article reviews the research progress about characteristics and related influencing factors of endometrial receptivity in PCOS patients.

An Update on the Progress of Endometrial Receptivity in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a significant public health issue with diverse presentations, including reproductive, metabolic, and psychological disorders. Although problems with ovulation, metabolism, and hormonal imbalance can be pharmacologically improved, even the excellent quality of transferred embryos does not necessarily increase the pregnancy rate. Poor endometrial receptivity in women with PCOS perturbs endometrial decidualization and blastocyst implantation, increasing adverse pregnancy outcomes, such as miscarriage and poor embryonic development. The etiological and pathophysiological mechanisms involved in defective endometrial receptivity in women with PCOS have not been fully elucidated to date. Various contributing factors have been reported as primary causes of defective endometrial receptivity in women with PCOS, including metabolic alterations, inflammatory events, and some abnormally expressed endometrial molecular markers. However, few studies to date have investigated in depth the complex mechanisms underlying the compromised endometrial receptivity in women with PCOS. This article reviews recent reports mainly on metabolic alterations and some new endometrial molecular markers in order to collate the existing data and improve our understanding in this field. The aim was to discuss current novel insights on defective endometrial receptivity in women with PCOS in order to provide a theoretical basis for reducing adverse pregnancy outcomes and improving the live birth rate in PCOS.

The Disorders of Endometrial Receptivity in PCOS and Its Mechanisms

Polycystic ovary syndrome (PCOS) is a mysterious and complicated endocrine disease with the combination of metabolic, reproductive, psychological dysfunctions. Impaired endometrial receptivity and ovulation disorders/anovulation are both important causes of PCOS-related infertility. However, change in endometrium has never received the same attention as ovulatory dysfunction. Besides, putting emphasis on endometrial function may be more realistic for PCOS-related infertility, given the wide use of assisted reproductive technology. The present review focuses on the disorders of endometrial receptivity of patients with PCOS, summarizes the changes of the indicators of endometrial receptivity including leukemia inhibitory factor, homeobox genes A, pinopodes, αvβ3-integrin, and intercellular junctions and also analyzes the possible mechanisms of decreased endometrial receptivity and its relationship with the main endocrine and metabolic disorders of PCOS such as hyperandrogenism, inflammation, insulin resistance, and obesity. Despite several biomarkers have been found to be associated with decreased endometrial receptivity in PCOS, the clinical relevance of these findings still awaits future clarification.

The Effect of Ageing on Clinical, Hormonal and Sonographic Features Associated with PCOS-A Long-Term Follow-Up Study

The knowledge of polycystic ovary syndrome (PCOS) natural history is limited. Our objective was to assess the effect of aging on clinical, hormonal and sonographic ovarian PCOS features and additionally to identify parameters that impact the course of PCOS. A secondary aim was to supply additional information on the reproductive outcome in women with previously diagnosed PCOS. A longitudinal cohort study with a median follow-up of 120.9 months was conducted, and 31 Caucasian women previously diagnosed with PCOS according to the Rotterdam criteria were re-examined at a median age of 35. Clinical examinations; transvaginal ultrasound scans; and lipid, E-selectin and sex hormone assessments were performed at the beginning and at the end of the follow-up. It was observed that menstrual cycles became regular and sonographic morphology of ovaries was normalized in 55% and 49% of the participants, respectively (all p < 0.05). At the final assessment, 55% of the women no longer met the criteria for PCOS (p < 0.05). The age, follicle-stimulating hormone (FSH) and E-selectin assessed at the baseline were the most important predictors of the PCOS persistence into later years (respectively, OR = 0.84, OR = 0.39, OR = 1.08, all p < 0.05). Ninety-five percent of the patients who had ever been trying to conceive became pregnant a minimum of once. The women with persistent PCOS had worse metabolic and reproductive parameters compared to the women with resolved PCOS. Positive correlations were found between the number of miscarriages and ovarian volume, LH, androstenedione, 17-hydroxyprogesterone and an increase in E-selectin during the follow-up (R = 0.46, R = 0.59, R = 0.54, R = 0.49, R = 0.47, all p < 0.05). In conclusion, progressing from the third to the fourth decade is connected with a reduction in PCOS features, which seems to have a great impact on fertility of women with a previous diagnosis of PCOS. FSH and E-selectin, as determined at the initial PCOS diagnosis, had an impact on the disappearance of the syndrome years after.

Low basal serum testosterone level is detrimental to the embryo implantation in the patients with severe endometriosis

AIM

Androgens have been reported to be associated with female fertility. The mean serum testosterone concentration in the patients with endometriosis was reported to be significantly lower than that without endometriosis. Our study was designed to investigate the influence of basal serum testosterone levels on the clinical outcome of in vitro fertilization (IVF) in the patients with III-IV stage endometriosis.

METHODS

This retrospective cohort study included 407 patients with III-IV stage endometriosis diagnosed by laparoscopic surgery. We studied the association of the basal serum testosterone level and the reproductive outcome of IVF.

RESULTS

The basal serum testosterone concentration was significantly higher in the pregnant group of patients with III-IV stage endometriosis. The further analyses demonstrated that the implantation rate of the basal serum testosterone concentration < 0.305 ng/mL group was significantly lower than the testosterone ≥ 0.305 ng/mL group (24.1% vs. 32.7%, p = 0.007). The clinical pregnancy and live birth rate of the basal serum testosterone < 0.305 ng/mL group were also lower than that of the testosterone ≥ 0.305 ng/mL group. Both initial and total dose of gonadotropins in the testosterone <0.305 ng/mL group are significantly higher than that of the testosterone ≥0.305 ng/mL group.

CONCLUSIONS

Our study demonstrated, for the first time, that the basal serum testosterone <0.305 ng/mL had an adverse impact on pregnancy outcomes of IVF-embryo transfer in the patients with III-IV stage endometriosis. Besides, the basal serum testosterone is also helpful in making individual stimulation protocol for the patients with advanced endometriosis before entering IVF cycles.

Endometrial function in women with polycystic ovary syndrome: a comprehensive review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. An endometrial component has been suggested to contribute to subfertility and poor reproductive outcomes in affected women.

OBJECTIVE AND RATIONALE

The aim of this review was to determine whether there is sufficient evidence to support that endometrial function is altered in women with PCOS, whether clinical features of PCOS affect the endometrium, and whether there are evidence-based interventions to improve endometrial dysfunction in PCOS women.

SEARCH METHODS

An extensive literature search was performed from 1970 up to July 2020 using PubMed and Web of Science without language restriction. The search included all titles and abstracts assessing a relationship between PCOS and endometrial function, the role played by clinical and biochemical/hormonal factors related to PCOS and endometrial function, and the potential interventions aimed to improve endometrial function in women with PCOS. All published papers were included if considered relevant. Studies having a specific topic/hypothesis regarding endometrial cancer/hyperplasia in women with PCOS were excluded from the analysis.

OUTCOMES

Experimental and clinical data suggest that the endometrium differs in women with PCOS when compared to healthy controls. Clinical characteristics related to the syndrome, alone and/or in combination, may contribute to dysregulation of endometrial expression of sex hormone receptors and co-receptors, increase endometrial insulin-resistance with impaired glucose transport and utilization, and result in chronic low-grade inflammation, immune dysfunction, altered uterine vascularity, abnormal endometrial gene expression and cellular abnormalities in women with PCOS. Among several interventions to improve endometrial function in women with PCOS, to date, only lifestyle modification, metformin and bariatric surgery have the highest scientific evidence for clinical benefit.

WIDER IMPLICATIONS

Endometrial dysfunction and abnormal trophoblast invasion and placentation in PCOS women can predispose to miscarriage and pregnancy complications. Thus, patients and their health care providers should advise about these risks. Although currently no intervention can be universally recommended to reverse endometrial dysfunction in PCOS women, lifestyle modifications and metformin may improve underlying endometrial dysfunction and pregnancy outcomes in obese and/or insulin resistant patients. Bariatric surgery has shown its efficacy in severely obese PCOS patients, but a careful evaluation of the benefit/risk ratio is warranted. Large scale randomized controlled clinical trials should address these possibilities.

Effect of Three Androgen Indexes (FAI, FT, and TT) on Clinical, Biochemical, and Fertility Outcomes in Women with Polycystic Ovary Syndrome

This work sought to evaluate the effects of three androgen indexes of free testosterone (FT), total testosterone (TT), and free-androgen index (FAI) on clinical phenotype, endocrine metabolic disorders, and fertility outcomes in women with polycystic ovary syndrome. The data in this study came from a large, multicenter, randomized double-blind controlled clinical trial involving 1000 infertile PCOS patients. Baseline phenotypic, endocrine, and metabolic parameters and fertility outcomes undergoing ovulation induction were collected. FAI is superior to FT, and FT is superior to TT in terms of their correlation with anthropometric parameters and metabolic profile. FT and TT were significantly positively correlated with LH/FSH. FAI and FT were significantly correlated with the incidence of metabolic syndrome. FAI, FT, and TT were significantly positively correlated with polycystic ovary morphology and menstrual period. FAI was significantly related ovulations per cycle, pregnancy, conception, and live birth rates. After adjusting for age, the increased FT level was significantly related to the decreased rates of ovulations per cycle, conception, and pregnancy. FAI is superior to FT and FT is superior to TT in terms of their correlation with phenotypic and metabolic parameters in PCOS patients. FAI and FT are important factors related to the fertility outcomes of infertile PCOS patients. Clinical trial registration number: NCT01573858.

Pathogenetic factors involved in recurrent pregnancy loss from multiple aspects

Recurrent pregnancy loss (RPL) is a common complication in obstetrics, affecting about 5% of women of childbearing age. An increase in the number of abortions results in escalation in the risk of miscarriage. Although concentrated research has identified numerous causes for RPL, about 50% of them remain unexplained. Pregnancy is a complex process, comprising fertilization, implantation, organ and tissue differentiation, and fetal growth, which is effectively controlled by a number of both maternal and fetal factors. An example is the immune response, in which T cells and natural killer cells participate, and inflammation mediated by tumor necrosis factor or colony-stimulating factor, which hinders embryo implantation. Furthermore, vitamin D affects glucose metabolism and inhibits embryonic development, whereas microRNA has a negative effect on the gene expression of embryo implantation and development. This review examines the causes of RPL from multiple perspectives, and focuses on the numerous factors that may result in RPL.