The regulation of ovary and conceptus on the uterine natural killer cells during early pregnancy

Association of adverse fetal outcomes with placental inflammation after oral gestational exposure to hexafluoropropylene oxide dimer acid (GenX) in Sprague-Dawley rats

Hexafluoropropylene oxide dimer acid (HFPO-DA), known as "GenX" for its trade name, is gradually taking the place of Perfluorooctanoic acid (PFOA). However, there is a poor understanding of the developmental effects of GenX. This study aims to explore whether GenX produces adverse effects on offspring development in Sprague-Dawley (SD) rats and the underlying mechanisms. Pregnant rats were orally administered with GenX (0, 1, 10 and 100 mg/kg/day) from gestational 0.5-19.5 days. Experimental data showed that the exposure to GenX resulted in increased rats' gestational weight gain, whereas both body weight and body length of their fetuses born naturally were significantly reduced. This could contribute to the developmental delays of fetal body weight, body length and tail length from postnatal 1-21 days. Histopathological evaluation of placenta indicated that GenX exposure led to neutrophil infiltration in decidual zone and congestion in labyrinth zone. Moreover, placental proteomics showed changes at the expression levels of the inflammation-related proteins in the Rap1 signaling pathway. In conclusion, gestational exposure to GenX induced fetal intrauterine and extrauterine development retardation in SD rats. Placental inflammation may play a key role in this process through the Rap1 signaling pathway.

Maternal, Fetal and Neonatal Outcomes Related to Recreational Cannabis Use during Pregnancy: Analysis of a Real-World Clinical Data Warehouse between 2010 and 2019

BACKGROUND

Cannabis is the main illicit psychoactive substance used in French childbearing women and very few data are available about adverse events (AEs) related to its use during pregnancy. The aim of this study was to evaluate the association between recreational cannabis use during pregnancy and adverse outcomes from a real-world clinical data warehouse.

METHODS

Data from the Poitiers University Hospital warehouse were analyzed between 1 January 2010 and 31 December 2019. Logistic regression models were used to evaluate associations between outcomes in three prenatal user groups: cannabis alone ± tobacco (C ± T) (n = 123), tobacco alone (T) (n = 191) and controls (CTRL) (n = 355).

RESULTS

Pregnant women in the C ± T group were younger (mean age: 25.5 ± 5.7 years), had lower pre-pregnancy body mass index (22.8 ± 5.5 kg/m2), more psychiatric history (17.5%) and were more likely to benefit from universal free health-care coverage (18.2%) than those in the T and CTRL groups. Cannabis use increases the occurrence of voluntary interruption of pregnancy, at least one AE during pregnancy, at least one neonatal AE, the composite adverse pregnancy outcome over 28, prematurity and small for gestational age.

CONCLUSION

Given the trivialization of recreational cannabis use during pregnancy, there is an urgent need to communicate on AEs of cannabis use during pregnancy.

The Neglected Uterine NK Cells/Hamperl Cells/Endometrial Stromal Granular Cell, or K Cells: A Narrative Review from History through Histology and to Medical Education

Reproductive immunology is at the forefront of research interests, aiming to better understand the mechanisms of immune regulation during gestation. The relationship between the immune system and the implanting embryo is profound because the embryo is semi-allogenic but not targeted by the maternal immune system, as expected in graft-versus-host reactions. The most prominent cell population at the maternal-fetal interface is the population of uterine natural killer (uNK) cells. Uterine NK cells are two-faced immunologically active cells, bearing comparison with Janus, the ancient Roman god of beginnings and endings. Their first face can be seen as natural killer cells, namely lymphocytes, which are critical for host defense against viruses and tumors. Even though uNK cells contain cytolytic molecules, their cytotoxic effect is not applied to classical target cells in vivo, playing a permissive rather than a defensive role. Their second face is crucial in maintaining physiological gestation-uNK cells show critical immunomodulatory functions with the potential to control embryo implantation and trophoblast invasion, regulate placental vascular remodeling, and promote embryonic/fetal growth. Therefore, we believe that their current designation "natural killer cells" (the first "cytotoxic" Janus's face) is misleading and inappropriate, considering their principal function is supporting and maintaining pregnancy. In this narrative review, we will focus on three lesser-known areas of knowledge about uNK cells. First, from the point of view of histology, we will comprehensively map the history of the discovery of these cells, as well as the current histological possibilities of their identification within the endometrium. To be brief, the discovery of uNK cells is generally attributed to Herwig Hamperl, one of the most influential and prominent representatives of German pathology in the 20th century, and his co-worker, Gisela Hellweg. Secondly, we will discuss the interesting aspect of terminology, since uNK cells are probably one of the human cells with the highest number of synonymous names, leading to significant discrepancies in their descriptions in scientific literature. From the first description of this cell type, they were referred to as endometrial granulocytes, granular endometrial stromal cells, or large granular lymphocytes until the end of the 1980s and the beginning of the 1990s of the last century, when the first publications appeared where the name "uterine NK cells" was used. The third area of present review is medical teaching of histology and clinical embryology. We can confirm that uNK cells are, in most textbooks, overlooked and almost forgotten cells despite their enormous importance. In the present narrative review, we summarize the lesser-known historical and terminological facts about uNK cells. We can state that within the textbooks of histology and embryology, this important cell population is still "overlooked and neglected" and is not given the same importance as in fields of clinical research and clinical practice.

Ovarian Stimulation in Mice Resulted in Abnormal Placentation through Its Effects on Proliferation and Cytokine Production of Uterine NK Cells

Ovarian stimulation is associated with an increased incidence of abnormal placentation. Uterine natural killer (uNK) cells are the major subpopulation of decidual immune cells, which are crucial for placentation. In a previous study, we found that ovarian stimulation impairs uNK cell density on gestation day (GD) 8.5 in mice. However, it was not clear how ovarian stimulation led to a reduction in the density of uNK cells. In this study, we constructed two mouse models, an in vitro mouse embryo transfer model and an estrogen-stimulated mouse model. We used HE and PAS glycogen staining, immunohistochemical techniques, q-PCR, Western blot, and flow cytometry to analyze the mouse decidua and placenta, and the results showed that SO resulted in a fetal weight reduction, abnormal placental morphology, decreased placental vascular density, and abnormal density and function of uNK cells. Our results suggest that ovarian stimulation resulted in aberrant estrogen signaling and may contribute to the disorder of uNK cells caused by ovarian stimulation. Together, these results provide new insights into the mechanisms of aberrant maternal endocrine environments and abnormal placentation.

Emerging Roles of Endocannabinoids as Key Lipid Mediators for a Successful Pregnancy

In recent years, Cannabis use/misuse for treating pregnancy-related symptoms and other chronic conditions has increased among pregnant women, favored by decriminalization and/or legalization of its recreational uses in addition to its easy accessibility. However, there is evidence that prenatal Cannabis exposure might have adverse consequences on pregnancy progression and a deleterious impact on proper neurodevelopmental trajectories in the offspring. Maternal Cannabis use could interfere with the complex and finely controlled role performed by the endocannabinoid system in reproductive physiology, impairing multiple gestational processes from blastocyst implantation to parturition, with long-lasting intergenerational effects. In this review, we discuss current clinical and preclinical evidence regarding the role of endocannabinoids in development, function, and immunity of the maternal–fetal interface, focusing on the impact of Cannabis constituents on each of these gestational processes. We also discuss the intrinsic limitations of the available studies and the future perspectives in this challenging research field.

Postpartum hepatitis and host immunity in pregnant women with chronic HBV infection

In order to develop immune tolerant to the fetal, maternal immune system will have some modification comparing to the time before pregnancy. Immune tolerance starts and develops at the maternal placental interface. In innate immunity, decidual natural killer (dNK) cells, macrophages and dendritic cells play a key role in immue tolerance. In adaptive immunity, a moderate increase of number and immune inhibition function of regulatory T cells (Treg) are essential for immune tolerance. The trophoblast cells and immune cells expressing indoleamine 2,3-dioxygenase (IDO), the trophoblast cells expressing HLA-G, and Th1/Th2 shifting to Th2 dominant and Th17/Treg shifting to Treg domiant are in favor of maternal fetal immune tolerance. Steroids (estrogen and progesterone) and human chorionic gonadotropin (HCG) also participate in immune tolerance by inducing Treg cells or upregulating immunosuppressive cytokines. Most of the patients with chronic HBV infection are in the "HBV immune tolerance period" before pregnancy, and the liver disease is relatively stable during pregnancy. In chronic HBV infection women, after delivery, the relative immunosuppression in vivo is reversed, and Th1 is dominant in Th1/Th2 and Th17 is dominant in Th17/Treg balance. After delivery, the number of Treg decrease and NK cells increase in quantity and cytotoxicity in peripheral blood. Liver NK cells may cause liver inflammation through a non-antigen specific mechanism. After delivery, the number of CD8⁺ T cells will increase and HBV specific T cell response recovers from the disfunction in pregnancy. Under the background of postpartum inflammation, the rapid decrease of cortisol after delivery, and especially the enhancement of HBV specific T cell response induced by HBV DNA and cytokines, are the main reasons for postpartum hepatitis. HBeAg positive, especially HBeAg<700 S/CO, and HBV DNA>3-5Log₁₀IU/ml are risk factors for postpartum hepatitis. Antiviral treatment in late pregnancy can reduce the incidence of mother to child transmission (MTCT) in chronic HBV infection women. Chronic HBV infection women have hepatitis both during pregnancy and more often in 12 weeks postpartum. It is generally agreed that postpartum hepatitis is mild symptoms and self-limited. Delaying drug withdrawal to 48 weeks can increase the seroconversion rate of HBeAg in delivery women with elevated alanine aminotransferase (ALT) in pregnancy.

Uterine Natural Killer Cells in the Context of Implantation: Immunohistochemical Analysis of Endometrial Samples from Women with Habitual Abortion and Recurrent Implantation Failure

Infertility affects approximately 48 million couples globally. Despite the enormous progress of the methods of reproductive medicine that has been made since the first test-tube baby was born in 1978, the implantation rate of day-3 embryos is only around 15-20 % and 30 % of day-5 embryos. Numerous strategies aim to improve implantation rates and prevent repeated implantation failure. However, there is no specific general recommendation leading to satisfying results. One of the many risk factors relevant in this regard is the uterine immunological make-up, mainly the uterine Natural Killer (uNK) cells. They orchestrate the overall immune response during implantation by influencing trophoblast invasion and vascular remodeling and throughout pregnancy, uNK cells are also the main immune cells at the maternal–fetal interface. Previously, uNK count has been correlated with various fertility issues including idiopathic recurrent miscarriage. The present study used endometrial samples collected from 256 patients with recurrent implantation failure (RIF), habitual abortion (HA) and idiopathic sterility. Samples were collected between day 19 and 21 of the menstrual cycle mainly by Pipelle endometrial sampling. The samples were fixed in formalin for 24 hours and further processed for immunohistochemistry using anti-CD56 to visualize this antigen marker of uNK cells. Immunohistochemical counting was performed to assess the low, normal, or elevated count of uNK cells. According to the one-way ANOVA test, the age of our patients did not have any influence on the count of uNK cells. With Spearman correlation analysis, we found statistically significant correlation (p-value 0.05) of -0.133 between prior miscarriage and lower uNK cell count. Using the same analysis we found statistically significant correlation (correlation 0.233 with p value 0.01) between number of uNK cells and activation status. Patients with higher uNK cells were more frequenty diagnosed with endometriosis (p-value 0.05, correlation 0.130). Patients with an immunological factor of sterility (defined by a clinical immunologist) had a lower chance of gravidity (-0.203 with p-value 0.01). Based on our results, we can confirm that there is a correlation between RIF, HA, idiopathic sterility, endometriosis, and immunological factor of sterility (uNK cell count). The true predictive value with regard to fertility outcomes needs to be addressed in future research.

Uterine Natural Killer Cells in the Context of Implantation: Immunohistochemical Analysis of Endometrial Samples from Women with Habitual Abortion and Recurrent Implantation Failure

Infertility affects approximately 48 million couples globally. Despite the enormous progress of the methods of reproductive medicine that has been made since the first test-tube baby was born in 1978, the implantation rate of day-3 embryos is only around 15-20 % and 30 % of day-5 embryos. Numerous strategies aim to improve implantation rates and prevent repeated implantation failure, however there is no specific general recommendation leading to satisfying results. One of the many risk factors relevant in this regard is the uterine immunological make-up, mainly the uterine Natural Killer (uNK) cells. They orchestrate the overall immune response during implantation by influencing trophoblast invasion and vascular remodeling and throughout pregnancy, uNK cells are also the main immune cells at the maternal-foetal interface. Previously, uNK count has been correlated with various fertility issues including idiopathic reccurent miscarriage. The present study used endometrial samples collected from 256 patients with recurrent implantation failure (RIF), habitual abortion (HA) and idiopathic sterility. Samples were collected between day 19 and 21 of the menstrual cycle mainly by Pipelle endometrial sampling. The samples were fixed in formalin for 24 hours and further processed for immunohistochemistry using anti-CD56 to visualize this antigen marker of uNK cells. Immunohistochemical counting was performed to assess the low, normal, or elevated count of uNK cells. According to the one-way ANOVA test, the age of our patients did not have any influence on the count of uNK cells. With Spearman correlation analysis, we found statistically significant correlation (p-value 0.05) of -0.133 between prior miscarriage and lower uNK cell count. Using the same analysis we found statistically significant correlation (correlation 0.233 with p-value 0.01) between number of uNK cells and activation status. Patients with higher uNK cells were more frequenty diagnosed with endometriosis (p-value 0.05, correlation 0.130). Patients with an immunological factor of sterility (defined by a clinical immunologist) had a lower chance of gravidity (-0.203 with p-value 0.01). Based on our results, we can confirm that there is a correlation between RIF, HA, idiopathic sterility, endometriosis, and immunological factor of sterility (uNK cell count). The true predictive value with regard to fertility outcomes needs to be addressed in future research.

Polarization disorder of decidual NK cells in unexplained recurrent spontaneous abortion revealed by single-cell transcriptome analysis

BACKGROUND

Unexplained recurrent spontaneous abortion (URSA) is one of the most common diseases in pregnancy and is mainly caused by immune disorders. The foetus is similar to semiallogeneic maternal tissue, so the balance of immune tolerance must be dynamically maintained during pregnancy. Decidual natural killer (dNK) cells primarily mediate the immune tolerance microenvironment at the maternal-fetal interface. By using single-cell RNA sequencing (scRNA-seq) and high-throughput transcriptome sequencing analysis, we explored the characteristic distribution of dNK cells in URSA patients.

METHODS

Control maternal-fetal interface tissue (from normal pregnant women, n = 3) and case maternal-fetal interface tissue (from patients with URSA, n = 3) samples were analysed by scRNA-seq and high-throughput transcriptome sequencing.

RESULTS

By scRNA-seq, we demonstrated the maturation process of the transition of dNK cells from cytotoxic characteristics to immune tolerance in transcriptome analysis. Moreover, compared with normal pregnant women, serious disturbances in the polarization process of dNK cells were found in URSA. Simultaneously, the transcriptional level of the extracellular matrix (ECM) in URSA patients showed a significant decrease. The dNK cells interacted with extravillous trophoblasts to achieve immune-tolerant polarization.

CONCLUSIONS

Insufficient expression of KIRs during dNK cell differentiation might be a key reason why polarized dNK cells still had high cytotoxic reactivity in URSA patients. Abnormal expression of ECM may affect the interaction of dNK cells with EVTs, making dNK cells immature. Both resulted in maternal immune intolerance to the foetus during pregnancy.

Biology and pathology of the uterine microenvironment and its natural killer cells

Tissues are the new frontier of discoveries in immunology. Cells of the immune system are an integral part of tissue physiology and immunity. Determining how immune cells inhabit, housekeep, and defend gut, lung, brain, liver, uterus, and other organs helps revealing the intimate details of tissue physiology and may offer new therapeutic targets to treat pathologies. The uterine microenvironment modulates the development and function of innate lymphoid cells [ILC, largely represented by natural killer (NK) cells], macrophages, T cells, and dendritic cells. These immune cells, in turn, contribute to tissue homeostasis. Regulated by ovarian hormones, the human uterine mucosa (endometrium) undergoes ~400 monthly cycles of breakdown and regeneration from menarche to menopause, with its fibroblasts, glands, blood vessels, and immune cells remodeling the tissue into the transient decidua. Even more transformative changes occur upon blastocyst implantation. Before the placenta is formed, the endometrial glands feed the embryo by histiotrophic nutrition while the uterine spiral arteries are stripped of their endothelial layer and smooth muscle actin. This arterial remodeling is carried out by invading fetal trophoblast and maternal immune cells, chiefly uterine NK (uNK) cells, which also assist fetal growth. The transformed arteries no longer respond to maternal stimuli and meet the increasing demands of the growing fetus. This review focuses on how the everchanging uterine microenvironment affects uNK cells and how uNK cells regulate homeostasis of the decidua, placenta development, and fetal growth. Determining these pathways will help understand the causes of major pregnancy complications.

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.

Mifepristone regulates macrophage-mediated natural killer cells function in decidua

Mifepristone has been used for first-trimester abortion and contraception. Nevertheless, its functional mechanism still needs to be elucidated. Decidua tissues were collected from 40 pregnant women who received (20 patients) or did not receive (20 patients) mifepristone. Immunofluorescence was used to analyze the effect of mifepristone on the quantity of CD56 and CD206 in decidua. in vitro assay, NK cells were isolated from decidua tissue and macrophages were induced from THP-1 cells. NK cells were co-cultured with macrophages pre-treated different concentrations of mifepristone (0 nmol/L, 200 nmol/L, 1800 nmol/L, and 25000 nmol/L); the cells' cytotoxicity and migration ability were analyzed using MTT assay and transwell assay, respectively. Si-TGF-β1, which was utilized to knock down the TGF-β1 expression in macrophages and human recombinant TGF-β1 were used to verify whether TGF-β1 was involved in the mifepristone regulation of NK cells function. The quantity of CD56 and CD206 decreased after mifepristone treatment. Moreover, the NK cells' cytotoxicity and migration ability were significantly increased by macrophages pre-treated with mifepristone in a dose-dependent manner. Moreover, compared with the si-NC group, the MTT absorbance rate of NK cells was significantly increased in the si-TGF-β1 group and was decreased in the human recombinant TGF-β1 group. Our data suggest that mifepristone, which regulates NK cells function through macrophages, was associated with the changes in TGF-β1 secreted by macrophages. This may be one of the mechanisms of mifepristone acting as contraceptive and abortion drugs at the maternal-fetal interface.

Differential molecular and hormonal changes in oocytes, granulosa cells and follicular fluid of pregnant and non-pregnant camels

This study aimed to compare the expression of genes regulating follicles development, survival and steroid hormones secretion in oocytes and granulosa cells (GCs) and study the correlation between their expression and follicular fluid (FF) levels of progesterone (P4) in pregnant and non-pregnant camels. In total, 138 ovarian pairs from slaughtered camels were used. Gene expression and hormonal assay were determined using real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The obtained results revealed that the number of follicles (3-8 mm) was significantly (P < 0.05) lower in pregnant, compared with non-pregnant, camels. P4 level in the FF was significantly (P < 0.05) higher in pregnant, compared with non-pregnant, camels. However, no significant (P > 0.05) difference was noticed in the oestradiol (E2) level. STAR, PTEN, IGF1 and BCL2 mRNA levels were significantly higher in GCs and significantly lower in oocytes of pregnant, compared with non-pregnant, camels. However, follicle-stimulating hormone receptor (FSHR) mRNA level was significantly lower in GCs and oocytes, and the BMP15 mRNA level was significantly lower in oocytes of pregnant, compared with non-pregnant, camels. P4 level in FF was positively correlated with STAR, PTEN, IGF1 and BCL2 mRNA levels in GCs and negatively correlated with BMP15 mRNA levels in oocytes and FSHR mRNA levels in GCs and oocytes of pregnant camels. It could be concluded that pregnancy-induced variations in oocytes and GC expression of BMP15, IGF1, FSHR, STAR, BCL2, and PTEN genes might be associated with a decrease in the number of follicles and an increase in the FF level of P4.

Cannabinoid Signalling in Immune-Reproductive Crosstalk during Human Pregnancy

Despite the intricate involvement of the endocannabinoid system in various physiological processes, it remains one of the most under-studied biological systems of the human body. The scope of endocannabinoid signalling is widespread, ranging from modulation of immune responses in innate and adaptive immunity to gestational processes in female physiology. Cannabinoid receptors are ubiquitously distributed in reproductive tissues and are thought to play a role in regulating the immune-reproductive interactions required for successful pregnancy, specifically among uterine natural killer cells and placental extravillous trophoblasts. The use of cannabis during pregnancy, however, can perturb endocannabinoid homeostasis through effects mediated by its major constituents, Δ-9-tetrahydrocannabinol and cannabidiol. Decidualization of the endometrium, invasion, and angiogenesis may be impaired as a consequence, leading to clinical complications such as miscarriage and preeclampsia. In this review, the crosstalk between endocannabinoid signalling in uterine natural killer cells and placental extravillous trophoblasts will be examined in healthy and complicated pregnancies. This lays a foundation for discussing the potential of targeting the endocannabinoid system for therapeutic benefit, particularly with regard to the emerging field of synthetic cannabinoids.

Crosstalk Between Trophoblasts and Decidual Immune Cells: The Cornerstone of Maternal-Fetal Immunotolerance

The success of pregnancy relies on the fine adjustment of the maternal immune system to tolerate the allogeneic fetus. Trophoblasts carrying paternal antigens are the only fetal-derived cells that come into direct contact with the maternal immune cells at the maternal–fetal interface. The crosstalk between trophoblasts and decidual immune cells (DICs) via cell–cell direct interaction and soluble factors such as chemokines and cytokines is a core event contributing to the unique immunotolerant microenvironment. Abnormal trophoblasts–DICs crosstalk can lead to dysregulated immune situations, which is well known to be a potential cause of a series of pregnancy complications including recurrent spontaneous abortion (RSA), which is the most common one. Immunotherapy has been applied to RSA. However, its development has been far less rapid or mature than that of cancer immunotherapy. Elucidating the mechanism of maternal–fetal immune tolerance, the theoretical basis for RSA immunotherapy, not only helps to understand the establishment and maintenance of normal pregnancy but also provides new therapeutic strategies and promotes the progress of immunotherapy against pregnancy-related diseases caused by disrupted immunotolerance. In this review, we focus on recent progress in the maternal–fetal immune tolerance mediated by trophoblasts–DICs crosstalk and clinical application of immunotherapy in RSA. Advancement in this area will further accelerate the basic research and clinical transformation of reproductive immunity and tumor immunity.

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.

Recent insights on indirect mechanisms in developmental toxicity of nanomaterials

BACKGROUND

Epidemiological and animal studies provide compelling indications that environmental and engineered nanomaterials (NMs) pose a risk for pregnancy, fetal development and offspring health later in life. Understanding the origin and mechanisms underlying NM-induced developmental toxicity will be a cornerstone in the protection of sensitive populations and the design of safe and sustainable nanotechnology applications.

MAIN BODY

Direct toxicity originating from NMs crossing the placental barrier is frequently assumed to be the key pathway in developmental toxicity. However, placental transfer of particles is often highly limited, and evidence is growing that NMs can also indirectly interfere with fetal development. Here, we outline current knowledge on potential indirect mechanisms in developmental toxicity of NMs.

SHORT CONCLUSION

Until now, research on developmental toxicity has mainly focused on the biodistribution and placental translocation of NMs to the fetus to delineate underlying processes. Systematic research addressing NM impact on maternal and placental tissues as potential contributors to mechanistic pathways in developmental toxicity is only slowly gathering momentum. So far, maternal and placental oxidative stress and inflammation, activation of placental toll-like receptors (TLRs), impairment of placental growth and secretion of placental hormones, and vascular factors have been suggested to mediate indirect developmental toxicity of NMs. Therefore, NM effects on maternal and placental tissue function ought to be comprehensively evaluated in addition to placental transfer in the design of future studies of developmental toxicity and risk assessment of NM exposure during pregnancy.

Gestational Perfluorooctanoic Acid Exposure Inhibits Placental Development by Dysregulation of Labyrinth Vessels and uNK Cells and Apoptosis in Mice

Perfluorooctanoic acid (PFOA) is a widely used perfluorinated compound and known to cause developmental toxicity which includes the increase of resorbed embryo, decrease of fetal survival, and fetal growth retardation. Nevertheless, whether it is associated with alteration of placental development remains unknown. Pregnant mice were gavaged with 0, 2.5, 5, 10 mg PFOA /kg/day from pregnancy day (PD) 1 to PD 13. Results showed that PFOA exposure markedly decreased the placental weight and caused interstitial edema of placenta. Laminin staining indicated that blood sinusoids area was shrunken in placenta of PFOA-exposed mice. Furthermore, PFOA treatment significantly reduced numbers of uNK cells. Western blot analysis revealed that levels of Bax and cleaved-caspase 3 proteins were markedly up-regulated in PFOA-treated groups. In addition, TEM examination showed that PFOA treatment caused rupture of nuclear membrane and nuclear pyknosis and fragmentation. Thus, our results suggested that gestational PFOA exposure significantly inhibited development of early placenta through shrinkage of labyrinth vessels and downregulation of uNK cells and apoptosis induction, which may result in adverse gestational outcomes.

Flutamide ameliorates uterine decidualization and angiogenesis in the mouse hyperandrogenemia model during mid-pregnancy

Background/Aim

Patients with polycystic ovary syndrome (PCOS), characterized by anovulation, hyperandrogenemia and polycystic ovaries, are still vulnerable to undergo recurrent pregnancy loss and premature labor even though the ovulatory process is pharmacologically recovered. However, its potential mechanism remains unknown. Thus, our aim was to investigate the effect and mechanism of hyperandrogenemia and flutamide (a non-steroidal anti-androgen) on the embryo implantation and pregnancy during mid-pregnancy.

Methods

We used a mouse model in which PCOS-like hyperandrogenemia was induced by subcutaneous injection of testosterone propionate. In this model, we observed the effect of hyperandrogenemia and flutamide on the decidualization, angiogenesis and uNK cells by methods of immunohistochemistry, quantitative PCR, western blotting and Dolichos biflorus agglutinin (DBA) lectin staining.

Results

Testosterone and flutamide treatment did not significantly influence the numbers of implanted embryo compared with the control group. However, different doses of testosterone significantly increased the ratio of resorbed /implanted embryo, decreased the level of prl8a2 mRNA and cyclin D3 protein, inhibited the uterine angiogenesis and reduced the numbers of uNK cells, but combined treatment with flutamide markedly decreased the resorbed embryos, increased expressions of prl8a2 mRNA and cyclin D3 protein and angiogenesis and numbers of uNK cells.

Conclusion

Flutamide treatment can efficiently ameliorate the hyperandrogenemia-induced the disorders in aspects of decidualization, angiogenesis and uNK cells, which further improve the poor endometrial receptivity in PCOS patients.

Immunomodulatory effects of progesterone and selective ligands of membrane progesterone receptors

Progesterone (P4) and its analogues regulate various reproductive processes, such as ovulation, implantation, pregnancy maintenance and delivery. In these processes, an important role is played by the immune cells recruited to the female reproductive organs and tissues, where they are exposed to the action of P4. Progestins regulate cellular processes, acting through nuclear steroid receptors (nSRs), membrane P4 receptors (mPRs), and through the sensors. It remains unclear, what type of receptors is used by P4 and its derivatives to exert their effect on the immune cells and how similar their effects are in different types of these cells. We have previously synthesized new progesterone derivatives, among which two selective mPRs ligands, not interacting with nSRs were identified. The objective of this study was to examine the effects of P4 and new selective mPRs ligands on the expression of pro- and anti-inflammatory cytokines in activated human peripheral blood mononuclear cells (PBMCs), THP-1 monocyte cells, and Jurkat T cells. It was demonstrated that the action of P4 and selective ligands was unidirectional, but in different types of the immune cells, their effects were different, and sometimes even opposite. In PBMCs, exposure to these steroids resulted in the increase of mRNA and secreted protein levels of IL-1β, TNFα, and IL-6 cytokines, as well as in the increase of INFγ mRNA level, decrease of IL-2 mRNA level, increase of TGFβ mRNA level, and decrease of IL-4 mRNA and IL-10 secreted protein levels. In monocytes, similarly to PBMCs, expression of IL-1β and TNFα mRNA was increased, but expression of IL-10 was also increased, and the TGFβ expression statistically significantly remained the same. In Jurkat T cells, expression of IL-2 and TNFα mRNA decreased, while expression of IL-10 increased, and expression of TGFβ did not change. Thus, progestins act on the immune cells through mPRs and have both pro- and anti-inflammatory effects, depending on the phenotypes of these cells. The data obtained are important for understanding the complexity of the immune system regulation by progestins, which depends on the type of the immune cells and individual characteristics of the immune system.

Killer-cell immunoglobulin-like receptors associated with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) affects the endocrine system and is associated with low-grade inflammation. Natural killer (NK) cells are involved in the defense of the female reproductive tract, folliculogenesis, ovulation and the menstrual cycle. The killer-cell immunoglobulin-like receptors (KIR) on the surface of NK cells modulate the activation and function of these cells after interacting with human leukocyte antigen (HLA) class I ligands. The objective of this study was to evaluate the possible association of the KIR and their HLA ligands with polycystic ovary syndrome.

METHODS

Ninety-three patients with PCOS according to the Rotterdam criteria and 104 healthy controls were included in this study. The HLA class I and KIR genotypes were determined using a PCR-SSO technique, rSSO Luminex®. In order to assess whether the distribution of the HLA and KIR genotypes was in Hardy-Weinberg equilibrium, Arlequin 3.1 software was used. The frequency distributions in the two study groups were compared using the chi-squared statistic with Yates´s correction using Open Epi software.

RESULTS

The higher frequencies of KIR3DS1-Bw4 (41% vs. 19%, Pc = 0.002; OR = 2.90) and homozygotic KIR2DS4-del (54% vs. 26%, Pc = 0.0002; OR = 3.316) in patients compared with controls suggest they confer susceptibility to PCOS. A lower frequency of KIR2DS4-full was observed in patients (43% vs. 70%, Pc = 0.0004, OR = 0.320).

CONCLUSION

KIR and its HLA ligands were associated with the development of PCOS in the studied population.

Gestational exposure to titanium dioxide nanoparticles impairs the placentation through dysregulation of vascularization, proliferation and apoptosis in mice

Background

Titanium dioxide nanoparticles (TiO₂ NPs) have recently found applications in a wide variety of consumer goods. TiO₂ NPs exposure significantly increases fetal deformities and mortality. However, the potential toxicity of TiO₂ NPs on the growth and development of placenta has been rarely studied during mice pregnancy.

Purpose

The objective of this study was to investigate the effects of maternal exposure of TiO₂ NPs on the placentation.

Methods

Mice were administered TiO₂ NPs by gavage at 0, 1 and 10 mg/kg/day from gestational day (GD) 1 to GD 13. Uteri and placentas from these mice were collected and counted the numbers of implanted and resorbed embryo and measured the placental weight on GD 13. Placental morphometry was observed by hematoxylin and eosin staining. The levels of Hand1, Esx1, Eomes, Hand2, Ascl2 and Fra1 mRNA were assessed by qRT-PCR. Uterine NK (uNK) cells were detected by using DBA lectin. Laminin immunohistochemical staining was to identify fetal vessels. Western blotting and transmission electron micrograph (TEM) were used to assess the apoptosis of placenta.

Results

No treatment-related difference was observed in the numbers of implanted and resorbed embryos and weight of placenta between the groups. However, 1 mg/kg/day TiO₂ NPs treatment significantly reduced the ratio of placenta/body weight on GD 13. The proportion of spongiotrophoblast in the 10 mg/kg/day dose group became higher than that in the control group, yet that of labyrinth was significantly lower in 10 mg/kg/day mice. The expression levels of Hand1, Esx1, Eomes, Hand2, Ascl2 and Fra1 mRNA markedly decreased in TiO₂ NP treated placentas. Furthermore, TiO₂ NPs treatment impaired the formation of intricate networks of fetal vessels and reduced the number of uNK cells, and inhibited proliferation and induced apoptosis of placenta by nuclear pyknosis, the activation of caspase-3 and upregulation of Bax protein and downregulation of Bcl-2 protein on GD 13.

Conclusion

Gestational exposure to TiO₂ NPs significantly impairs the growth and development of placenta in mice, with a mechanism that seems to be involved in the dysregulation of vascularization, proliferation and apoptosis. Therefore, our results suggested the need for great caution while handling of the nanomaterials by workers and specially pregnant consumers.