Cytokines: Important for implantation?

Brucella melitensis Rev1Δwzm: Placental pathogenesis studies and safety in pregnant ewes

One of the main causes of human brucellosis is Brucella melitensis infecting small ruminants. To date, Rev1 is the only vaccine successfully used to control ovine and caprine brucellosis. However, it is pathogenic for pregnant animals, resulting in abortions and vaginal and milk shedding, as well as being infectious for humans. Therefore, there is an urgent need to develop an effective vaccine that is safer than Rev1. In efforts to further attenuate Rev1, we recently used wzm inactivation to generate a rough mutant (Rev1Δwzm) that retains a complete antigenic O-polysaccharide in the bacterial cytoplasm. The aim of the present study was to evaluate the placental pathogenicity of Rev1Δwzm in trophoblastic cells, throughout pregnancy in mice, and in ewes inoculated in different trimesters of pregnancy. This mutant was evaluated in comparison with the homologous 16MΔwzm derived from a virulent strain of B. melitensis and the naturally rough sheep pathogen B. ovis. Our results show that both wzm mutants triggered reduced cytotoxic, pro-apoptotic, and pro-inflammatory signaling in Bewo trophoblasts, as well as reduced relative expression of apoptosis genes. In mice, both wzm mutants produced infection but were rapidly cleared from the placenta, in which only Rev1Δwzm induced a low relative expression of pro-apoptotic and pro-inflammatory genes. In the 66 inoculated ewes, Rev1Δwzm was safe and immunogenic, displaying a transient serological interference in standard RBT but not CFT S-LPS tests; this serological response was minimized by conjunctival administration. In conclusion, these results support that B. melitensis Rev1Δwzm is a promising vaccine candidate for use in pregnant ewes and its efficacy against B. melitensis and B. ovis infections in sheep warrants further study.

Innate and adaptive immune dysregulation in women with recurrent implantation failure

Recurrent implantation failure (RIF) is a condition where a woman fails to obtain pregnancy after multiple embryo transfer cycles, even with superior-quality blastocysts. There are various factors that can contribute to RIF, including immunologic disturbances. The immune system is extremely important during pregnancy. Immune cells such as T cells, B cells, natural killer (NK) cells, and macrophages (MQ) are present in the female reproductive tract and are accountable for regulating the immune response to invading pathogens and maintaining tissue homeostasis. Dysregulation of these immune cells can lead to inflammation, which can impair fertility. One of the most common immunological disturbances observed in RIF is an altered Th1/Th2 ratio, along with changes in NK cell and macrophage numbers. In addition, the presence of some antibodies, such as anti-ovarian antibodies, can also contribute to RIF. Interleukins have been implicated in the development of an inflammatory response that can interfere with successful embryo implantation. As a result, a comprehensive understanding of immunological compartments in RIF women could assist us in determining the immunological origins of this disease. We will discuss immunological factors that might contribute to RIF etiology, including cellular and molecular components.

Effect of blastocyst development on hatching and embryo implantation

The mammalian zygote, formed after a sperm fertilizes an egg, undergoes several rounds of mitosis and morphogenesis to form the blastocyst. During the peri-implantation period, the blastocyst hatches out of the zona pellucida (ZP) and invades the receptive uterine endometrium. This process promotes maternal-fetal dialogue at the physiological and molecular level, thereby initiating the implantation process. Blastocyst hatching is a consequence of elevated osmotic pressure due to active Na+/K+ ion transporter in the blastocyst cavity, as well as proteases produced by trophectoderm (TE) that hydrolyze the ZP. This review summarizes the process underpinning blastocyst hatching, such as the hatching schedule, the location of TEs during initial hatching out of the ZP, the molecules involved in blastocyst hatching, and how these processes affect implantation events. Additionally, we focus on identifying crucial molecules that may influence the quality of implantation and predict the outcome of embryo implantation. Further understanding the mechanism of these molecules may help us to improve the efficiency of Assisted reproductive technology (ART) in livestock breeding. This review provides insight into embryonic development, specifically during the short-term process of blastocyst hatching and its effects on the following implantation.

Serum Cu, Zn and IL-1β Levels May Predict Fetal Miscarriage Risk After IVF Cycles: A Nested Case-Control Study

To explore the association between serum-related indicators (levels of inflammatory cytokines and essential trace elements) and miscarriage risk among infertile women undergoing assisted reproductive techniques (ART) on the 14th day after embryo transfer, and to develop and establish a multivariable algorithm model that might predict pregnancy outcome. According to a nested case-control study design, a total of 100 miscarriage cases and 100 live birth controls were included in this study, and women in both groups were infertile and have underwent in vitro fertilization (IVF). Pregnancy tests were performed and serum levels of five essential trace elements (vanadium (V), copper (Cu), zinc (Zn), selenium (Se) and molybdenum (Mo)) and five inflammatory cytokines (interleukin-1β (IL-1β), IL-6, IL-8, IL-10 and tumor necrosis factor-α (TNF-α)) of the participants were measured on the 14th day after embryo transfer. The serum levels of five inflammatory cytokines were determined by multiple magnetic bead enzyme immunity analyzer; and the serum concentrations of five elements were determined simultaneously by inductively coupled plasma‒mass spectrometry (ICP ‒ MS). The logistic regression was used to evaluate the relationship between these serum indices and miscarriage risk among women undergoing ART, and a predictive model of pregnancy outcome based on these indices was established. The levels of IL-10, IL-1β and TNF-α of infertile women in the live birth group were significantly higher than those in the miscarriage group (p = 0.009, p < 0.001, p = 0.006), and the levels of V, Cu, Zn and Se of infertile women in the live birth group were also significantly higher than those in the miscarriage group (all p < 0.001). Through logistic regression analyses, we found that serum levels of IL-1β, TNF-α, V, Cu, Zn and Se were significantly and negatively associated with miscarriage risk. Different combination prediction models were generated according to the results of logistic regression analyses, and the combination of IL-1β, Cu and Zn had the best prediction performance. The area under the curve (AUC) was 0.776, the sensitivity of the model was 60% and the specificity was 84%. In conclusion, the serum-related indicators of women undergoing ART on the 14th day after embryo transfer, including the inflammatory cytokines such as IL-1β and TNF-α and the essential trace metal elements such as V, Cu, Zn and Se, were negatively correlated with miscarriage risk. A multivariate algorithm model to predict pregnancy outcome among women undergoing ART was established, which showed that IL-1β, Cu and Zn might synergistically predict pregnancy outcome.

Extremely low-frequency electromagnetic field (ELF-EMF) induces alterations in epigenetic regulation in the myometrium - An in vitro study

Previous research by the authors indicated that an extremely low-frequency electromagnetic field (ELF-EMF) evokes molecular alterations in the porcine myometrium. It was hypothesized that the ELF-EMF could induce alterations in the epigenetic regulation of gene expression in the myometrium. In the current study, slices of the porcine myometrium during the peri-implantation period (n = 4) were used for further in vitro exposition to ELF-EMF (50 Hz, 8 mT, 2 h treatment duration). The study tested whether the ELF-EMF may affect: 1/the expression of DNA (cytosine-5)-methyltransferase 1 (DNMT1) and DNA (cytosine-5)-methyltransferase 3a (DNMT3a), 2/the level of genomic DNA methylation, and 3/the level of amplification of methylated and unmethylated variants of promoter regions of selected genes with altered expression in response to ELF-EMF. It was found that ELF-EMF treatment increased DNMT1, decreased DNMT3a mRNA transcript and protein abundance, and increased the level of genomic DNA methylation. The direction of alterations in the level of amplification of methylated and unmethylated variants of the promoter region of selected genes with altered expression, i.e. prodynorphin (PDYN), interleukin 15 (IL15) signal transducer and activator of transcription 5A (STAT5A), tumor necrosis factor (TNF), and between down-regulated genes were early growth response 2 (EGR2), hyaluronan and proteoglycan link protein 1 (HAPLN1), and uteroferrin associated basic protein-2 (UABP2), mostly involving the direction of changes in their transcriptional activity, which was evaluated in a previous study by the authors. Thus, ELF-EMF radiation disturbs epigenetic mechanisms, which may underlay ELF-EMF-related transcriptomic alterations in the myometrium.

Defects in protective cytokine profiles in spontaneous miscarriage in the first trimester

OBJECTIVE

To study differences in cytokine expression profiles between women with ongoing pregnancy and those experiencing spontaneous miscarriage, among women who presented with threatened miscarriage before week 16 of gestation.

DESIGN

Prospective cohort study.

SETTING

Academic hospital.

PATIENT(S)

In this prospective cohort study, 155 pregnant women, comprising normal pregnant women recruited from antenatal clinics (n = 97) and women with threatened miscarriage recruited from an emergency walk-in clinic (n = 58).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Sixty-five serum cytokines quantified using multiplex immunoassay correlated with miscarriage outcomes.

RESULT(S)

Among women presenting with threatened miscarriage, those who eventually miscarried had significantly lower levels of interleukin (IL)-2, IL-12p70, IL-17A, B-cell-activating factor, B lymphocyte chemoattractant, basic nerve growth factor, interferon-γ, tumor necrosis factor-related apoptosis-inducing ligand, thymic stromal lymphopoietin, and tumor necrosis factor-α and higher levels of vascular endothelial growth factor A, IL-21, and stromal cell-derived factor 1α than those with ongoing pregnancy. Comparisons between normal pregnancies and women with threatened miscarriage who eventually miscarried revealed significant differences across 7 cytokines: B-cell-activating factor; B lymphocyte chemoattractant; basic nerve growth factor; IL-17A; fractalkine/CX3CL1; vascular endothelial growth factor A; and CCL22. Vascular endothelial growth factor A exhibited a negative correlation with the progesterone level (r = -0.270). The cluster of significant cytokines alludes to T cell proliferation, B-cell proliferation, natural killer cell-mediated cytotoxicity, and apoptosis as important pathways that determine pregnancy outcomes. Bioinformatic analysis further revealed alteration of the suppressor of cytokine signaling proteins family of Janus kinase-signal transducer and activator of transcription signaling axis by cytokines as a plausible key molecular mechanism in spontaneous miscarriage.

CONCLUSION(S)

This study demonstrates that the regulated balance between the proinflammatory and anti-inflammatory pathways is crucial to maintaining pregnancy. A better understanding of the cytokines associated with immunomodulatory effects may lead to novel targets for the prediction and treatment of spontaneous miscarriage.

Role of inflammatory factors in the etiology and treatment of recurrent implantation failure

Recurrent implantation failure (RIF) is characterized by the absence of implantation after high-grade embryos are transferred to the endometrium by at least three in vitro fertilization cycles. It is one of the most important factors contributing to reproductive failure. After numerous barriers have been overcome to obtain good-quality embryos, RIF causes extreme distress and frustration in women and couples. In recent years, significant progress has been made in understanding how inflammatory factors, which include pro-inflammatory factors, anti-inflammatory factors, chemokines, and other molecules, contribute to RIF. Immunological abnormalities, hypercoagulability, and reproductive diseases are considered potential causes of RIF. In alloimmune disorders, inflammatory factors can affect the success rate of embryo implantation by altering T helper (Th)1/Th2 and Th17/regulatory T cell ratios and causing imbalances of uterine natural killer cells and macrophages. Autoimmune disorders can also lead to RIF. Inflammatory factors also play key roles in RIF-related disorders such as hypercoagulability, chronic endometritis, adenomyosis, hydrosalpinx, and endometriosis. This review focuses on the roles of inflammatory factors in RIF, including immune factors, blood hypercoagulable states, and reproductive diseases such as chronic endometritis, adenomyosis, hydrosalpinx, and endometriosis. It also summarizes the different treatments according to the causes of RIF and discusses the efficacy of sirolimus, peripheral blood mononuclear cells, low-dose aspirin combined with low-molecular-weight heparin, blocking interleukin-22, and gonadotropin-releasing hormone agonists in the treatment of RIF.

Associations between ubiquitin, follicle-stimulating hormone, and sex steroid hormones in the failed to conceive female dromedary camels raised in hot climates

Background and Aim:

The reproductive management of female dromedary camels involves traditional implications that are widespread among desert camel raisers. Several subfertility clinical manifestations impede pregnancy and elongate the interval between parturitions. Ubiquitin is a novel-specific protein, referred to recently as a biomarker for reproductive performance in male and female mammals. Therefore, this study aimed to investigate the association between subfertility clinical status and the peripheral levels of ubiquitin versus follicle-stimulating hormone (FSH), progesterone, and estradiol.

Materials and Methods:

According to the clinical diagnoses, 80 female dromedaries admitted to the university clinic were categorized into six female groups suffering from endometritis (EN, 28; 35%), inactive ovaries (IO, 18; 22.5%), ovarian hydrobursitis (BU, 19; 23.75%), vaginal adhesions (VA, 7; 8.75%), salpingitis (SA, 4; 5%), and cervicitis (CE, 4; 5%). In addition, five normal fertile non-pregnant females served as controls (CONs). All animals underwent ultrasonography and blood sampling for hormone and ubiquitin determinations.

Results:

The results revealed a significant (p < 0.05) increase in ubiquitin in the CE (577.22 pg/mL) and VA (670.92 pg/mL) females. However, lower ubiquitin levels but still higher than the CON were noted in females with other symptoms (225.76, 425.79, 394.02, 414.96, and 393.92 pg/mL in the CON, BU, SA, IO, and EN, respectively). Concomitantly, the mean levels of FSH revealed a similar trend, showing higher (p < 0.05) levels in CE (2.79 mIU/mL) and VA (2.5 pg/mL) females. In contrast, no change was observed in FSH among other groups than CON (2.11, 2.17, 2.01, 2.24, and 2.13 mIU/mL in CON, BU, SA, IO, and EN, respectively). There was no difference in the progesterone levels among groups; however, estradiol-17ß levels significantly differed (p < 0.01), showing the highest level (629.15 pg/mL) in the SA group with no significant difference among other groups.

Conclusion:

Thus, ubiquitin could be used as a biomarker for genital tract inflammation in female camels raised in hot climates.

Kinetics of Placental Infection by Different Smooth Brucella Strains in Mice

Abortion and reproductive failures induced by Brucella are the main symptoms of animal brucellosis. Laboratory animal models are essential tools of research to study the Brucella pathogenesis before experimentation in natural hosts. To extend the existing knowledge, we studied B. melitensis 16M (virulent) and Rev1 (attenuated) as well as B. suis bv2 infections in pregnant mice. Here, we report new information about kinetics of infection (in spleens, blood, placentas, vaginal shedding, and foetuses), serum cytokine profiles, and histopathological features in placentas and the litter throughout mice pregnancy. Both B. melitensis strains showed a marked placental tropism and reduced viability of pups (mainly in 16M infections), which was preceded by an intense Th1-immune response during placental development. In contrast, B. suis bv2 displayed lower placental tropism, mild proinflammatory immune response, and scarce bacterial transmission to the litter, thus allowing foetal viability. Overall, our studies revealed three different smooth Brucella patterns of placental and foetal pathogenesis in mice, providing a useful animal model for experimental brucellosis.

The Role of Interleukins in Recurrent Implantation Failure: A Comprehensive Review of the Literature

Recurrent implantation failure (RIF) is a multifactorial condition affecting 10-15% of in vitro fertilization (IVF) couples. Data suggest that functional dysregulation of the endometrial immune system constitutes one of the main pathophysiological mechanisms leading to RIF. The aim of this article is to provide a thorough presentation and evaluation of the role of interleukins (ILs) in the pathogenesis of RIF. A comprehensive literature screening was performed summarizing current evidence. During implantation, several classes of ILs are secreted by epithelial and stromal endometrial cells, including IL-6, IL-10, IL-12, IL-15, IL-18, and the leukemia inhibitory factor. These ILs create a perplexing network that orchestrates both proliferation and maturation of uterine natural killer cells, controls the function of regulatory T and B cells inhibiting the secretion of antifetal antibodies, and supports trophoblast invasion and decidua formation. The existing data indicate associations between ILs and RIF. The extensive analysis performed herein concludes that the dysregulation of the ILs network indeed jeopardizes implantation leading to RIF. This review further proposes a mapping of future research on how to move forward from mere associations to robust molecular data that will allow an accurate profiling of ILs in turn enabling evidence-based consultancy and decision making when addressing RIF patients.

Excessive endoplasmic reticulum stress drives aberrant mouse trophoblast differentiation and placental development leading to pregnancy loss

KEY POINTS

Endoplasmic reticulum (ER) stress promotes placental dysmorphogenesis and is associated with poor pregnancy outcomes. We show that unfolded protein response signalling pathways located in the ER drive differentiation of mouse trophoblast stem cells into trophoblast subtypes involved in development of the placental labyrinth zone and trophoblast invasion. In a mouse model of chronic ER stress (Eif2s1^tm1RjK ), higher ER stress in homozygous blastocysts is accompanied by reduced trophectoderm cell number and developmental delay and also is associated with an increased incidence of early pregnancy loss. Administration of the chemical chaperone, tauroursodeoxycholic acid, to Eif2s1^{+/ tm1RjK} heterozygous females during pregnancy alleviated ER stress in the mutant placenta, restored normal trophoblast populations and reduced the frequency of early pregnancy loss. Our results suggest that alleviation of intrauterine ER stress could provide a potential therapeutic target to improve pregnancy outcome in women with pre-gestational metabolic or gynaecological conditions.

ABSTRACT

Women with pre-gestational health conditions (e.g. obesity, diabetes) or gynaecological problems (e.g. endometriosis) are at increased risk of adverse pregnancy outcomes including miscarriage, pre-eclampsia and fetal growth restriction. Increasing evidence suggests that unfavourable intrauterine conditions leading to poor implantation and/or defective placentation are a possible causative factor. The endoplasmic reticulum (ER) unfolded protein response (UPR^ER ) signalling pathways are a convergence point of various physiological stress stimuli that can be triggered by an unfavourable intrauterine environment. Therefore, we explored the impact of ER stress on mouse trophoblast differentiation in vitro, mouse blastocyst formation and early placenta development in the Eif2s1^tm1RjK mutant mouse model of chronic ER stress. Chemically-manipulated ER stress or activation of UPR^ER pathways in a mouse trophoblast stem cell line promoted lineage-specific differentiation. Co-treatment with specific UPR^ER pathway inhibitors rescued this effect. Although the inner cell mass was unaffected, the trophectoderm of homozygous Eif2s1^tm1RjK blastocysts exhibited ER stress associated with a reduced cell number. Furthermore, one-third of Eif2s1^tm1RjK homozygous blastocysts exhibited severe developmental defects. We have previously reported a reduced trophoblast population and premature trophoblast differentiation in Eif2s1^tm1RjK homozygous placentas at mid-gestation. Here, we demonstrate that treatment of Eif2s1^+/tm1RjK heterozygous pregnant females with the chemical chaperone tauroursodeoxycholic acid alleviated ER stress, restored the trophoblast population and reduced the frequency of embryonic lethality. Our data suggest that therapeutic targeting of ER stress may improve pregnancy outcome in women with pre-gestational metabolic or gynaecological conditions.

The impact of indomethacin on the number of oocytes retrieved and IVF outcomes in patients with poor ovarian response

OBJECTIVE

The aim of this retrospective case-control study was to analyze the effect of administering indomethacin after triggering final oocyte maturation in patients with poor ovarian response (POR) on the cycle cancellation rate due to premature ovulation (PO), the number of oocytes retrieved and the clinical outcomes of IVF cycles.

STUDY DESIGN

A total of 214 patients with POR, diagnosed according to the Bologna criteria, who underwent fresh IVF cycle via flexible gonadotrophin-releasing hormone antagonist (GnRH-ant) protocol were enrolled in the study. The control group consisted of 100 patients, whereas the indomethacin group included 114 patients who received 100 mg rectal indomethacin administered twice within the same day (twelve hours apart) -starting at twelve hours after triggering. Cycle cancelation rates (CCR), number of oocytes retrieved (nOR), implantation rates (IR), biochemical pregnancy (BP) and clinical pregnancy loss rates (CPL), ongoing pregnancy rates (OPR) and live birth rates (LBR) were compared between the indomethacin and control groups.

RESULTS

The CCR rate was significantly lower in the indomethacin group (1.8%) compared to the control group (1.8% vs %12%, p = 0.01). In the control group, those with cycle cancellation were older than those without cycle cancellation (mean age 42.2 ± 2.3 years vs. 39.36 ± 4.3 years, p = 0.001) and had lower anti-Müllerian hormone levels and lower antral follicle count (0.59 ± 0.2 ng/mL vs 0.79 ± 0.2 ng/mL, p = 0.001 and 4 ± 0.6 vs 5.7 ± 1.7, p = 0.001, respectively). In multivariable analysis, when the dependent variable in the logistic regression model was coded as the absence of cycle cancellation, it was observed that only indomethacin had a statistically significant effect on cycle cancellation (β = -1.931, standard error = 0.832, Exp(B) = 0.145, p = 0.020). nOR was higher in the indomethacin group than control group but the difference did not reach significance (p = 0.07). Moreover, the IR, OPR and LBR, BP and CPL values were similar in the indomethacin and control groups (p > 0.05).

CONCLUSIONS

Based on data from this study, it can be concluded that indomethacin reduces cycle cancelation due to PO in patients with POR -without compromising implantation and pregnancy rates. However, further randomized controlled trials with larger sample sizes are required to clarify the definitive effect of indomethacin in the treatment of patients with POR.

Trophoblast derived extracellular vesicles specifically alter the transcriptome of endometrial cells and may constitute a critical component of embryo-maternal communication

BACKGROUND

The period of time when the embryo and the endometrium undergo significant morphological alterations to facilitate a successful implantation-known as "window of implantation"-is a critical moment in human reproduction. Embryo and the endometrium communicate extensively during this period, and lipid bilayer bound nanoscale extracellular vesicles (EVs) are purported to be integral to this communication.

METHODS

To investigate the nature of the EV-mediated embryo-maternal communication, we have supplemented trophoblast analogue spheroid (JAr) derived EVs to an endometrial analogue (RL 95-2) cell layer and characterized the transcriptomic alterations using RNA sequencing. EVs derived from non-trophoblast cells (HEK293) were used as a negative control. The cargo of the EVs were also investigated through mRNA and miRNA sequencing.

RESULTS

Trophoblast spheroid derived EVs induced drastic transcriptomic alterations in the endometrial cells while the non-trophoblast cell derived EVs failed to induce such changes demonstrating functional specificity in terms of EV origin. Through gene set enrichment analysis (GSEA), we found that the response in endometrial cells was focused on extracellular matrix remodelling and G protein-coupled receptors' signalling, both of which are of known functional relevance to endometrial receptivity. Approximately 9% of genes downregulated in endometrial cells were high-confidence predicted targets of miRNAs detected exclusively in trophoblast analogue-derived EVs, suggesting that only a small proportion of reduced expression in endometrial cells can be attributed directly to gene silencing by miRNAs carried as cargo in the EVs.

CONCLUSION

Our study reveals that trophoblast derived EVs have the ability to modify the endometrial gene expression, potentially with functional importance for embryo-maternal communication during implantation, although the exact underlying signalling mechanisms remain to be elucidated.

Effect of the Electromagnetic Field (EMF) Radiation on Transcriptomic Profile of Pig Myometrium during the Peri-Implantation Period-An In Vitro Study

The electromagnetic field (EMF) affects the physiological processes in mammals, but the molecular background of the observed alterations remains not well established. In this study was tested the effect of short duration (2 h) of the EMF treatment (50 Hz, 8 mT) on global transcriptomic alterations in the myometrium of pigs during the peri-implantation period using next-generation sequencing. As a result, the EMF treatment affected the expression of 215 transcript active regions (TARs), and among them, the assigned gene protein-coding biotype possessed 90 ones (differentially expressed genes, DEGs), categorized mostly to gene ontology terms connected with defense and immune responses, and secretion and export. Evaluated DEGs enrich the KEGG TNF signaling pathway, and regulation of IFNA signaling and interferon-alpha/beta signaling REACTOME pathways. There were evaluated 12 differentially expressed long non-coding RNAs (DE-lnc-RNAs) and 182 predicted single nucleotide variants (SNVs) substitutions within RNA editing sites. In conclusion, the EMF treatment in the myometrium collected during the peri-implantation period affects the expression of genes involved in defense and immune responses. The study also gives new insight into the mechanisms of the EMF action in the regulation of the transcriptomic profile through lnc-RNAs and SNVs.

CD91 Derived Treg Epitope Modulates Regulatory T Lymphocyte Response, Regulates Expression of Costimulatory Molecules on Antigen-Presenting Cells, and Rescues Pregnancy in Mouse Pregnancy Loss Model

The loss of immune tolerance to fetal antigens may result in reproductive failure. The downregulated number and activity of T regulatory lymphocytes, which are critical for the establishment of immune tolerance to fetal antigens, during pregnancy may lead to miscarriage. The adoptive transfer of Tregs prevents fetal loss in abortion-prone mice. Recently, we demonstrated that the administration of tregitopes, which are short peptides found in human and mouse immunoglobulins (IgGs), decreased the incidence of abortions in female CBA/J mice mated with DBA/2J mice. Here, two non-IgG source peptides (SGS and LKD) that can potentially bind to the major histocompatibility complex II (MHC II) with high affinity and induce Treg expansion were designed in silico. The immune dysregulation-induced pregnancy failure mouse model was used to evaluate the effect of SGS and LKD on immune response and pregnancy outcome. The fetal death rate in the SGS-treated group was lower than that in the phosphate-buffered saline-treated group. SGS and LKD upregulated the splenic pool of Tregs and modulated the T-helper cell (Th1)/Th2-related cytokine response at the preimplantation stage. Additionally, SGS and LKD downregulated the expression of CD80 and MHC class II molecules in splenic CD11c⁺ antigen-presenting cells. Thus, SGS treatment can result in beneficial pregnancy outcomes. Additionally, SGS peptide-mediated immunomodulation can be a potential therapeutic strategy for immune dysregulation-induced pregnancy failure.

Decidua-derived granulocyte macrophage colony-stimulating factor induces polymorphonuclear myeloid-derived suppressor cells from circulating CD15+ neutrophils

STUDY QUESTION

Do decidua-derived factors stimulate the conversion of circulating neutrophils to polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) in early human pregnancy?

SUMMARY ANSWER

Circulating neutrophils can acquire PMN-MDSC-like phenotypes and function via phosphorylated signal transducer and activator of transcription 5/programmed death ligand 2 (pSTAT5/PD-L2) signalling after stimulation with decidua-derived granulocyte macrophage colony-stimulating factor (GM-CSF).

WHAT IS KNOWN ALREADY

PMN-MDSCs are an important immunoregulatory cell type in early pregnancy. Neutrophils are of high heterogeneity and plasticity and can polarize to immunosuppressive PMN-MDSCs upon stimulation.

STUDY DESIGN, SIZE, DURATION

For analysis of myeloid-derived suppressor cell (MDSC) subset proportions, 12 endometrium tissues and 12 peripheral blood samples were collected from non-pregnant women, and 40 decidua tissues and 16 peripheral blood samples were obtained from women with normal early pregnancy undergoing elective surgical pregnancy termination for nonmedical reasons with gestation age of 6-10 weeks. Twenty-nine decidua tissues were collected for isolation of CD15+ PMN-MDSCs. Twenty endometrium tissues and 30 decidua tissues were collected for cytokine analysis, immunohistochemistry or neutrophil stimulation. Peripheral blood samples were obtained from 36 healthy donors for isolation of CD3+ T cells and CD15+ neutrophils.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The proportion of MDSC subsets in the decidua and peripheral blood of normal early pregnancy, endometrium and peripheral blood of non-pregnant women was analysed by flow cytometry. The phenotypes and function of decidual PMN-MDSCs and circulating neutrophils were compared by flow cytometry. Circulating neutrophils were stimulated with decidual explant supernatant (DES) and the phenotypes were measured by flow cytometry and immunofluorescence. The suppressive capacity of decidual PMN-MDSCs and DES-conditioned neutrophils was analysed by flow cytometry with or without anti-programmed cell death-1 (PD-1) antibody. Cytokines from DES and endometrial explant supernatant (EES) were detected by a Luminex assay. GM-CSF expression was determined by ELISA and immunohistochemistry. Neutrophils were stimulated with DES, EES, DES with anti-GM-CSF antibody or EES with GM-CSF. CD11b, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), PD-L2 and pSTAT5 expression were measured by flow cytometry.

MAIN RESULTS AND THE ROLE OF CHANCE

The frequency of PMN-MDSCs was significantly increased in the decidua of early pregnancy compared with peripheral blood of non-pregnant women, the endometrium of non-pregnant women or peripheral blood during early pregnancy. Decidual PMN-MDSCs suppressed T-cell proliferation and cytokine production. Phenotypes of decidual PMN-MDSCs were similar to mature activated neutrophils. DES-induced CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation in neutrophils. The PD-L2 expression in neutrophils was dependent on STAT5 phosphorylation. Both decidual PMN-MDSCs and DES-conditioned neutrophils suppressed T-cell proliferation via PD-1 signalling. GM-CSF was up-regulated in the decidua and induced CD11b, LOX-1 and PD-L2 expression on neutrophils. DES significantly induced CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation. Anti-GM-CSF antibody remarkably blocked such stimulation in neutrophils. EES did not induce CD11b, LOX-1, PD-L2 expression or STAT5 phosphorylation, while GM-CSF treatment sufficiently stimulated CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation in neutrophils.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The study was based on in vitro experiments and we were not able to evaluate neutrophils differentiation to PMN-MDSCs in other sites before entering the maternal-foetal interface due to the limited availability of human samples. This needs to be explored using murine models.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study demonstrating that decidual PMN-MDSCs are a group of immunoregulatory cells with mature status, and that neutrophils can be induced to a PMN-MDSC-like phenotype with decidua-derived GM-CSF via pSTAT5/PD-L2 signalling. This study indicates that GM-CSF can facilitate immune tolerance of early pregnancy through regulating PMN-MDSCs and further provides a potential role of GM-CSF in prevention and treatment for pregnancy complications.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (81671481) and National Natural Science Foundation of China (81871179). All authors have no competing interests to declare.

Disturbed progesterone signalling in an advanced preclinical model of endometriosis

RESEARCH QUESTION

Do human endometriosis organoids recapitulate aberrant progesterone signalling in the disease to serve as advanced experimental models for uncovering epigenetic mechanisms involved in attenuated progesterone response in endometriosis?

DESIGN

Initially, the organoids were established from acquired biopsies (women with and without endometriosis) and characterized by morphological, histological and immunostaining analyses.

RESULTS

A panel of endometriosis-related genes showed a pattern of expressions in cytochrome c oxidase subunit II (COX2), matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase-3 (TIMP3), transforming growth factor beta 1 (TGF-β1), and zinc finger E-box binding homeobox 1 (ZEB1), and a contradictory expression pattern for cadherin (CDH1), POU class 5 homeobox 1 (POU5F1; also known as OCT4), and Nanog homeobox (NANOG) in the endometriosis organoids that is concordant with published research. These endometriosis organoids failed to upregulate 17β-Hydroxysteroid dehydrogenase 2 (17HSDβ2), progestogen associated endometrial protein (PAEP), secreted phosphoprotein 1 (SPP1), and leukaemia inhibitory factor (LIF) in response to progesterone at the level observed in control endometrium organoids. Progesterone receptor B (PRB) gene expression significantly decreased in both eutopic and ectopic organoids compared with control endometrium organoids. DNA hypermethylation, as an epigenetic mechanism for suppression of transcription, was detected at the PRB promoter in the eutopic, but not ectopic, organoids. Therefore, other epigenetic mechanisms, such as histone modifications and microRNAs, may be responsible for PRB downregulation in ectopic organoids.

CONCLUSIONS

Endometriosis organoids are powerful preclinical models that can be used to investigate the molecular mechanisms involved in endometriosis-associated progesterone resistance.

Local action of cytokines and immune cells in communication between the conceptus and uterus during the critical period of early embryo development, attachment and implantation - Implications for embryo survival in cattle: A review

Early embryo development, implantation and pregnancy involve a complex dialogue between the embryo and mother. In cattle this dialogue starts as early as days 3-4 when the embryo is still in the oviduct, and it continues to implantation. Immunological processes involving cytokines, mast cells and macrophages form an important part of this dialogue. Amongst the cytokines, interleukin-6 (Il-6) and leukemia inhibitory factor (LIF) are secreted by both the embryo and uterine endometrium and form part of an ongoing and reciprocating dialogue. Mast cells and macrophages populate the uterine endometrium during embryo development and are involved in achieving the correct balance between inflammatory and anti-inflammatory reactions at the uterus that are associated with embryo attachment and implantation. Embryo loss is the major cause of reproductive wastage in cattle, and livestock generally. A deeper understanding of immunological processes during early embryo development will help to achieve the next step change in the efficiency of natural and assisted breeding.

Role of intrauterine administration of transfected peripheral blood mononuclear cells by GM-CSF on embryo implantation and pregnancy rate in mice

One of the effective treatments in women with recurrent implantation failure (RIF) is the use of immune cells to facilitate embryo implantation. Previous studies have shown that intrauterine transmission of peripheral blood mononuclear cells (PBMC) increased the embryo implantation rate. In this study using B6D2F1 (C57BL/6 × DBA2) mice, a fragment of the granulocyte macrophage colony-stimulating factor (Gm-csf) gene was cloned into an enhanced green fluorescent protein vector (pEGFP-N1) and then transfected into PBMC. The protein level of GM-CSF was evaluated in the transfected PBMC and untransfected PBMC by ELISA. Attachment of mouse embryos and the mRNA expression levels of leukemia inhibitory factor (Lif), vascular endothelial growth factor (Vegf), matrix metalloproteinase 9 (Mmp9), Gmcsf-receptor (Gmcsf-r) and interleukin 6 (Il6) in vitro were assessed by real-time PCR in endometrial cells. To determine the pregnancy rate and number of implantation sites in vivo, the mouse uterine horns were analyzed on Day 7.5 post coitum. A greater amount of GM-CSF was produced in PBMC transfected with recombinant vector (552 pg/mL) compared with the untransfected PBMC (57 pg/mL) and PBMC transfected with empty vector (34 pg/mL) (P < 0.05). The data showed that the embryo attachment rate and mRNA expression levels (Vegf [1.7-fold], Mmp9 [1.4-fold], Lif [1.5-fold], Gm-csf r [1.6-fold] and Il6 [1.2-fold]) in the in vitro study (P < 0.01), pregnancy rate (P < 0.01) and number of implantation sites (P < 0.01) in the in vivo investigation (P < 0.05) were increased in PBMC transfected with recombinant vector compared with the PBMC group. The study demonstrated that, in mice, endometrium immunotherapy with transfected PBMC that contained recombinant GM-CSF before embryo implantation was effective in improving embryo implantation and endometrial receptivity.

Endometrial preparation with etanercept increased embryo implantation and live birth rates in women suffering from recurrent implantation failure during IVF

Recurrent implantation failure (RIF),  defined as ≥3 failed in vitro fertilization (IVF) cycles with the accumulated transfer of at least five embryos, plague many infertile women. The exact cause is unknown; however, evidence supports the immune system, specifically the Tumor Necrosis Factor (TNF) pathway. Etanercept (a TNFα antagonist) has been shown to improve pregnancy rates in women with rheumatoid arthritis or endometriomas; therefore, this study aimed to determine the effectiveness of etanercept for IVF in RIF women. Eighty-three RIF women were recruited from the Ingenes Institute in Mexico City for this single-arm, prospective study. All patients underwent a similar IVF protocol and received etanercept (4 × 25 mg every 72 h) after endometrial preparation, if applicable, and at embryo transfer. IVF endpoints assessed were embryo implantation (h-βCG >10 mg/dL at Day 14), the presence of a gestational sac, live birth, and birth weight. All women reported no side-effects associated with the etanercept treatment. 75.9 % of the cohort achieved embryo implantation, 74.7 % developed gestational sacs, and the ongoing pregnancy/live birth rate was at 62.7 %. However, 56.7 % of the live births were preterm (<37 weeks) and 60.5 % of the births were underweight (<2500 g). When stratified by fresh or frozen cycles or by the ova source (patient versus donor), the results were not significantly different with respect to the implantation rate, formation of gestational sacs, and the live birth rate. Here, we showed that using etanercept during endometrial preparation improves IVF outcomes in RIF women.

Endometrial receptivity and embryo implantation in carnivores-commonalities and differences with other mammalian species

Endometrial receptivity and embryo implantation processes are a major point of pregnancy failure in many mammalian species, including humans. Although reproductive biology in many carnivore species remains enigmatic, the few that have been studied so far are invaluable comparative models. The goals of this review are to (1) summarize current data on the mechanisms involved in uterine receptivity and embryo implantation in carnivores, including commonalities and differences with other mammalian species and (2) identify research priorities to better understand a key phenomenon in a critical group of mammals. Besides unique reproductive traits in some carnivores (induced vs. spontaneous ovulation in cats, ovulation at the germinal vesicle stage in dogs), preimplantation embryo development is comparable with other orders. However, the timing of implantation varies, especially in species having an embryonic diapause. Mechanisms involved in endometrial receptivity and decidualization still remain to be fully understood, but specific markers have already been identified. Importantly, the use of endogenous hormones to control the ovarian activity may impact endometrial receptivity and subsequent embryo implantation. Next, research efforts should take advantage of advanced technologies to further study embryo implantation in carnivores and to provide more relevant models to reproductive medicine or for the conservation of rare and endangered species.

Successful implantation is associated with a transient increase in serum pro-inflammatory cytokine profile followed by a switch to anti-inflammatory cytokine profile prior to confirmation of pregnancy

OBJECTIVE

To compare the changing peripheral levels of inflammation-related cytokine profile during a 9-day period after blastocyst transfer between women who did and did not conceive.

DESIGN

Prospective, observational, and longitudinal study.

SETTING

University-affiliated hospital.

PATIENT(S)

Forty-seven women with infertility who were undergoing single day-5 blastocyst transfer were recruited.

INTERVENTION(S)

This prospective observational and longitudinal study on 47 women with infertility was performed in an in vitro fertilization unit from December 2018 to August 2019. The amounts of a range of cytokines was measured on serial blood samples obtained during a 9-day period after blastocyst transfer.

MAIN OUTCOME MEASURE(S)

Serial blood samples were obtained on the day of embryo transfer, and 3, 6, and 9 days afterward for measurement of serum interferon gamma (IFN-γ), tumor necrosis factor alpha, interleukin (IL)-2, IL-4, IL-10, IL-12, IL-13, IL-17, IL-18, and IL-22 using cytometric bead arrays; transforming growth factor beta 1 (TGF-β1) was measured using commercial enzyme-linked immunosorbent assay kits.

RESULT(S)

The cytokine profile was similar between the women who conceived and those who did not on the day of blastocyst transfer. In women who conceived, IFN-γ and IL-17 (pro-inflammatory cytokines) exhibited a transient and significant increase on day 3 after blastocyst transfer, which decreased to the baseline levels by day 6. Meanwhile, IL-10 (anti-inflammatory cytokine) was increased significantly on days 6 and 9, and TGF-β1 (anti-inflammatory cytokine) was increased significantly on day 9 after blastocyst transfer. In women who did not conceive, there was a more pronounced increase in IFN-γ and IL-17 (pro-inflammatory cytokines) on day 3, which was sustained on days 6 and 9 without a switch to an anti-inflammatory cytokine profile.

CONCLUSION(S)

Among women who conceived after blastocyst embryo transfer, there was a transient and modest increase in serum pro-inflammatory cytokine profile (IFN-γ and IL-17) 3 days after blastocyst transfer, which was followed by a switch to anti-inflammatory cytokine profile (increase IL-10 and TGF-β1) by 6 days after blastocyst transfer and the latter increase was sustained 9 days after blastocyst transfer, when pregnancy was confirmed.

An Experimental Model for Peri-conceptual COVID-19 Pregnancy Loss and Proposed Interventions to Optimize Outcomes

Reports appear to give reassurance that vertical transmission near term is unlikely, but risks of incidental SARS-CoV-2 infection during fertility treatments, at embryo implantation, or in the first trimester remain unknown. If early pregnancy sequela in the current COVID-19 pandemic are modeled from the 2004 Coronavirus outbreak data, then SARS-CoV-2 infection proximate to blastocyst nidation is likely to cause implantation failure or spontaneous abortion. Our model explains why this outcome is less attributable to virus-associated maternal pulmonary distress and instead derives from systemic inflammation and interference with trophectoderm-endometrium molecular signaling required for implantation. COVID-19 is often accompanied by high levels of IL-6, IL-8, TNF-alpha and other cytokines, a process implicated in pulmonary collapse and systemic organ failure. Yet when regarded in an early reproductive context, this "cytokine storm" of COVID-19 triggers a pro-coagulative state hostile to normal in utero blastocyst/fetal development. Evidence from obstetrics is accumulating to show that mothers with SARS-CoV-2 deliver placentas with abnormal interstitial villi fibrin deposits, diffuse infarcts, and hemangiomatous changes. This model classifies such lesions as permissive at term but catastrophic near embryo implantation or early first trimester pregnancy. Clinical experience with recurrent pregnancy loss offers workable interventions to address this challenge, but success will depend on prompt and accurate SARS-CoV-2 diagnosis. Although no professional guidelines currently exist for SARS-CoV-2 in early pregnancy, this model would warrant a high-risk designation for such cases; these patients should receive priority access to screening and treatment resources.

Determining the Molecular Background of Endometrial Receptivity in Adenomyosis

Background: Adenomyosis is a gynaecological condition with limited evidence of negative impact to endometrial receptivity. It is commonly associated with endometriosis, which has been shown to alter endometrial expression patterns. Therefore, the candidate genes identified in endometriosis could serve as a source to study endometrial function in adenomyosis. Methods: Transcripts/proteins associated with endometrial receptivity in women with adenomyosis or endometriosis and healthy women were obtained from publications and their nomenclature was adopted according to the HUGO Gene Nomenclature Committee (HGNC). Retrieved genes were analysed for enriched pathways using Cytoscape/Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Reactome tools to prioritise candidates for endometrial receptivity. These were used for validation on women with (n = 9) and without (n = 13) adenomyosis. Results: Functional enrichment analysis of 173, 42 and 151 genes associated with endometriosis, adenomyosis and healthy women, respectively, revealed signalling by interleukins and interleukin-4 and interleukin-13 signalling pathways, from which annotated LIF, JUNB, IL6, FOS, IL10 and SOCS3 were prioritised. Selected genes showed downregulated expression levels in adenomyosis compared to the control group, but without statistical significance. Conclusion: This is the first integrative study providing putative candidate genes and pathways characterising endometrial receptivity in women with adenomyosis in comparison to healthy women and women with endometriosis.

Effects of quercetin on Aroclor 1254-induced expression of CYP450 and cytokines in pregnant rats

The present study aimed to investigate the protective effect of quercetin on polychlorinated biphenyls (PCB)-induced liver and embryo damage in pregnant Sprague-Dawley rats. Pregnant rats were divided into five groups, and then were orally gavaged daily with peanut oil (vehicle) or a commercial PCB mixture (Aroclor 1254) - with or without co-treatment with 75, 150, or 300 mg/kg quercetin - on gestation days (GD) 4-7. At GD 9, all rats were euthanized, and their blood, liver, and uterus were collected. Expressions of CYP₄₅₀ mRNA and protein in liver, cytokines (IFNγ, IL-2, IL-4, and IL-6) and IFNγ/IL-4 ratios in liver and sera, liver morphology, and the status of implanted embryos were analyzed. The results showed Aroclor 1254 treatment alone caused hepatic cord damage (i.e. cell disorganization, swelling, decreased cytoplasm, vacuolization), and that quercetin co-treatment appeared to mitigate this damage. Similarly, levels of CYP1A1 and CYP2B1 mRNA in livers of Aroclor 1254-only-treated rats were significantly higher than those in rats co-treated with quercetin. Hepatic and sera levels of IFNγ, IL-2, IL-6, and IFNγ/IL-4 ratios, and the ratio of delayed-development embryos, all increased in Aroclor 1254-treated rats, but were relatively decreased as a result of quercetin co-treatments. IL-4 levels were decreased by Aroclor 1254 and tended to increase back to normal when quercetin was used. The results indicated that quercetin imparted a protective effect against Aroclor 1254-induced toxicity in pregnant rats, in part, by modulating levels of important pro-inflammatory cytokines and reducing induced CYP1A1 and CYP2B1 expression.

Yellow Fever Vaccination in a Mouse Model Is Associated With Uninterrupted Pregnancies and Viable Neonates Except When Administered at Implantation Period

The potential risk of yellow fever (YF) infection in unvaccinated pregnant women has aroused serious concerns. In this study, we evaluated the effect of the YF vaccine during gestation using a mouse model, analyzing placental structure, immunolocalization of the virus antigen, and viral activity at the maternal-fetal barrier and in the maternal liver and fetus. The YF vaccine (17DD) was administered subcutaneously at a dose of 2.0 log₁₀ PFU to CD-1 mice on gestational days (gd) 0.5, 5.5, and 11.5 (n = 5–10/group). The control group received sterile saline (n = 5–10/group). Maternal liver, implantation sites with fetus, and placentas were collected on gd18.5. The numbers of implantation sites, reabsorbed embryos, and stillborn fetuses were counted, and placentas and live fetuses were weighed. Tissues (placenta, fetuses, and liver) of vaccinated pregnant mice on gd5.5 (n = 15) were paraffin-embedded in 10% buffered-formalin and collected in TRIzol for immunolocalization of YF vaccine virus and PCR, respectively. PCR products were also subjected to automated sequence analysis. Fetal growth restriction (p < 0.0001) and a significant decrease in fetal viability (p < 0.0001) occurred only when the vaccine was administered on gd5.5. In stillbirths, the viral antigen was consistently immunolocalized at the maternal-fetal barrier and in fetal organs, suggesting a transplacental transfer. In stillbirths, RNA of the vaccine virus was also detected by reverse transcriptase-PCR indicating viral activity in the maternal liver and fetal tissues. In conclusion, the findings of this study in the mouse suggest that vaccination did not cause adverse outcomes with respect to fetal development except when administered during the early gestational stage, indicating the implantation period as a susceptible period in which the YF vaccine virus might interfere with pregnancy.

Effect of empiric intravenous intralipid therapy on pregnancy outcome in women with unexplained recurrent implantation failure undergoing intracytoplasmic sperm injection-embryo transfer cycle: a randomized controlled trial

To evaluate the effect of empiric intralipid infusion therapy on pregnancy outcomes for patients with unexplained recurrent implantation failure (RIF) undergoing intracytoplasmic sperm injection (ICSI). A total of 142 patients with a history of unexplained RIF (3 or more cycles) were included in this randomized controlled trial. Patients were randomized into two groups, study group (n = 71) and control group (n = 71). The study group received intralipid 20% infusion on the day of embryo transfer (ET) and a second dose on the day of pregnancy test. The clinical pregnancy rate in the study group was 36.6% (n = 26) compared to 28.2% (n = 20) in the control group (OR 1.47, CI 0.72-2.98, p = .282). The live birth rate in the study group was 18.3% (n = 13) and 14.1% (n = 10) in the control group (OR 1.37, CI 0.55-3.36, p=.49). No side effects of intralipid therapy were reported in the study period. There was improvement in the pregnancy rate among women with unexplained RIF who received empiric intralipid infusion therapy; however, this improvement did not reach statistical significance.

Immunological adaptations in pregnancy that modulate rheumatoid arthritis disease activity

During pregnancy, the fetus that grows within the maternal uterus is not rejected by the maternal immune system. To enable both tolerance towards the fetus and defence against pathogens, modifications of the maternal immune system occur during gestation. These modifications are able to bring about a natural improvement in disease activity of some autoimmune diseases, such as rheumatoid arthritis (RA). Various mechanisms of the immune system contribute to the phenomenon of pregnancy-related improvement of RA, and the cessation of these immunomodulatory mechanisms after delivery correlates with postpartum disease flare. HLA disparity between mother and fetus, glycosylation of IgG, immunoregulatory pathways, and alterations in innate and adaptive immune cells and their cytokines have important roles in pregnancy and in pregnancy-related amelioration of RA.

The Unique Microbiome and Innate Immunity During Pregnancy

A successful pregnancy depends on not only the tolerance of the fetal immune system by the mother but also resistance against the threat of hazardous microorganisms. Infection with pathogenic microorganisms during pregnancy may lead to premature delivery, miscarriage, growth restriction, neonatal morbidity, and other adverse outcomes. Moreover, the host also has an intact immune system to avoid these adverse outcomes. It is important to note the presence of normal bacteria in the maternal reproductive tract and the principal role of the maternal-placental-fetal interaction in antimicrobial immunity. Previous studies mainly focused on maternal infection during pregnancy. However, this review summarizes the new views on the study of the maternal microbiome and expounds the innate immune defense mechanism of the maternal vagina and decidua as well as how cytotrophoblasts and syncytiotrophoblasts recognize and kill bacteria in the placenta. Fetal immune systems, thought to be weak, also exhibit an immune defense function that is indispensable for maintaining the safety of the fetus. The skin, lungs, and intestines of the fetus during pregnancy constitute the main immune barriers. These findings will provide a new understanding of the effects of normal microbial flora and how the host resists harmful microbes during pregnancy. We believe that it may also contribute to the reference on the clinical prevention and treatment of gestational infection to avoid adverse pregnancy outcomes.

Peroxisome proliferator-activated receptor alpha regulates the expression of the immune response mediators in the porcine endometrium during the estrous cycle and early pregnancy

PROBLEM

Cytokines are immune response mediators that play an important role in the regulation of reproductive functions. An association between cytokines and peroxisome proliferator receptors (PPARs) has been reported in various tissues, including the endometrium. The present study aimed to evaluate the impact of PPARα ligands on the expression of nuclear factor kappa B (NF-κB) and cytokines (interleukin [IL]-1β, IL-4, IL-6, IL-8, IL-10, and LIF) in the porcine endometrium in different reproductive stages.

METHODS OF STUDY

Endometrial slices were collected from gilts on days 10-12 or 14-16 of the estrous cycle and pregnancy. Endometrial tissue explants were incubated in vitro in the presence or absence of PPARα agonist WY-14643 and antagonist MK886. Expression of mRNA and protein for NF-ĸB and selected cytokines was evaluated by real-time PCR and immunoblot.

RESULTS

PPARα agonist WY-14643 decreased the mRNA expression of NF-κB in most of the analyzed stages (excluding days 10-12 of the estrous cycle), but increased the expression of NF-κB protein (excluding days 14-16 of pregnancy). The WY-14643 increased expression of IL-1β and IL-6 proteins, and the mRNA expression of IL-8 and LIF, decreased IL-4 expression, and did not affect the mRNA and protein expression of IL-10.

CONCLUSION

The obtained results demonstrate that PPARα is involved in the regulation of NF-κB and cytokine expression in the porcine endometrium. PPARα ligands exert a varied influence on immune system components, which could be attributed to differences in the receptivity of porcine endometrial tissue during the reproductive cycle.

Are the cytokines TNF alpha and IL 1Beta early predictors of embryo implantation? Cross sectional study

The cross-talk between endometrium and embryo is not accessible to the researcher for obvious ethical reasons that let understand why implantation remains the black box of reproduction. We aimed to detect of the concentrations of IL-1β and TNF-α in endometrial secretion at the time of oocyte retrieval for early prediction of implantation. One hundred twenty women participated in the study during ICSI cycles. All women participating in the study included the following criteria; age; 22-36 years, BMI; less than 35 kg/m², a husband with oligo- or oligoasthenospermia. All women received controlled ovarian hyperstimulation and immediately after ovum pickup, an intrauterine flushing was done. Embryo transfer was done at the blastocyst stage five days after ovum pick up. Serum pregnancy tests were done for all women. The clinical pregnancy was defined as the appearance of the gestational sac and positive embryo cardiac activity was confirmed by TVS. The ongoing pregnancy was detected by abdominal ultrasound at 12 weeks. The participants were divided into two groups: the pregnant group and the non-pregnant group. Thirty-two and half percent of women got pregnant. There were non-significant differences between the two groups regarding the demographic, clinical and laboratory data except for the duration of infertility and concentrations of TNF-α and IL-1β. The concentrations of TNF-α and IL-1β were significantly higher in the pregnant group than the non-pregnant group.Therefore,The use of TNF-α and IL-1β to predict implantation in IVF is promising especially before embryo transfer. Clinical trial.gov registration NCT02854514.

Endometrium immunomodulation by intrauterine insemination administration of treated peripheral blood mononuclear cell prior frozen/thawed embryos in patients with repeated implantation failure

In assisted reproductive technology (ART) programmes, approximately 10% of infertile patients have at least two or three repeated implantation failures (RIFs) after an in vitro fertilization (IVF) protocol. Successful implantation mainly depends on local immune tolerance mechanisms involving a spectrum of cytokines, interleukins and growth factors. The latter have played pivotal roles in the recruitment of immune cells (and notably T-lymphocyte cells). In total, 250 couples participating in frozen-thawed embryo transfer programme were incorporated in a randomized clinical trial (peripheral blood mononuclear cells (PBMC) subgroup: n=122; control subgroup: n=128). In the PBMC group, a blood sample was collected 5 days before the scheduled frozen-thawed embryo transfer; PBMCs were isolated using Ficoll separation and then cultured for 72 h. Two days prior to embryo transfer, 0.4 ml of cultured PBMCs were transferred into the patient's uterus. Although the clinical pregnancy rate was higher in the PBMC group (34.4%) than in the control group (23.4%), this difference was not statistically significant (P=0.05 in a chi-squared test). Nevertheless, when we limited the analysis to patients with ≥3 RIFs (n=138), there was a significant difference in the clinical pregnancy rate between the PBMC group (38.6%) and the control group (19.7%; P=0.01). Our results imply that PBMC transfer can be part of effective fertility treatment for patients with RIF.

Role of Tim-3 in Decidual Macrophage Functional Polarization During Abnormal Pregnancy With Toxoplasma gondii Infection

Vertical transmission of the intracellular parasite Toxoplasma gondii (T. gondii) can lead to devastating consequences during gestation. Tim-3, a negative immune regulator, is constitutively expressed on decidual macrophages, but its specific role during T. gondii infection has not yet been explored. In the present study, we discovered that Tim-3 plays an important role in the abnormal pregnancy due to T. gondii infection using Tim-3^−/− pregnant mice and anti-Tim-3 neutralizing antibody treated human decidual macrophages. The results showed that abnormal pregnancy outcomes were more prevalent in Tim-3^−/− infected pregnant mice than in wild-type infected pregnant mice. Tim-3 expression in decidual macrophages was significantly down-regulated after T. gondii infection both in vitro and in vivo. Tim-3 down-regulation by T.gondii infection could strengthen M1 activation and weaken M2 tolerance by changing the M1 and M2 membrane molecule expression, arginine metabolic enzymes synthesis, and cytokine secretion profiles of decidual macrophages. Moreover, Tim-3 down-regulation by T.gondii infection led to PI3K-AKT phosphorylation inhibition, downstream transcription factor C/EBPβ expression, and SOCS1 activation, which resulted in enzymes synthesis regulation and cytokines secretion. Our study demonstrates that Tim-3 plays an indispensable role in the adverse pregnancy outcomes caused by T. gondii infection.

Impact of Metformin and Pioglitazone on Serum Level of Tumor Necrosis Factor-Alpha and Lipid Profiles during Implantation Window in Diabetic Rats

Background

The present study was designed to evaluate serum lipid profile and tumor necrosis factor-alpha (TNF-ɑ) level in diabetic rats at implantation time. Type 2 diabetes mellitus (T2DM) could affect various systems, including innate immune system and it causes chronic low-grade inflammation, increasing level of TNF-ɑ. Furthermore, T2DM is often accompanied by impaired lipid profile. Metformin and pioglitazone are used as the first and second lines of treatment for T2DM.

Materials and Methods

In this experimental study, 35 adult virgin female wistar rats, weighting 175-225 g, were randomly categorized into five groups: i. Control, ii. Sham, iii. Nicotinamide (NA)+streptozotocin (STZ) induced T2DM, iv. Diabetic+pioglitazone (20 mg/kg/day for 28 days oral administration), and v. Diabetic+metformin (100 mg/kg/day for 28 days oral administration). At the time of implantation, TNF-ɑ level in serum of rats was measured by ELISA kit. Glucose was measured using photometric method and lipid profiles were calculated by enzymatic methods.

Results

Level of TNF-ɑ in the diabetic group was significantly higher than other groups (P<0.001). In metformin treated group, TNF-ɑ serum level was also significantly higher than pioglitazone treated group (P<0.001). Fasting blood sugar (FBS) and lipid profiles were significantly higher in diabetic group.

Conclusion

Metformin and pioglitazone have similar effects on glucose, lipid profiles and TNF-ɑ serum levels. Among these drugs, pioglitazone has more efficient influence on TNF-α serum level, in comparison with metformin.

Interleukin-3 Polymorphism is Associated with Miscarriage of Fresh in Vitro Fertilization Cycles

The aim of this study was to examine the association between interleukin (IL) genes polymorphisms and in vitro fertilization (IVF) outcome. A prospective cohort analysis was performed at a Women’s Hospital IVF centre of 1015 female patients undergoing fresh non-donor IVF cycles. The effects of the following six single nucleotide polymorphisms (SNPs) in five IL genes on IVF outcomes were explored: IL-1α (rs1800587 C/T), IL-3 (rs40401 C/T), IL-6 (rs1800795 C/G), IL-15 (rs3806798 A/T), IL-18 (rs187238 C/G) and IL-18 (rs1946518 G/T). The main outcome measures included clinical pregnancy, embryo implantation, abortion and live birth rates. There were no statistically significant differences in clinical pregnancy, embryo implantation and live birth rates in the analysis of 1015 patients attempting their first cycle of IVF. Infertile women with IL-3 homozygous major genotype had a higher abortion rate than those with heterozygous and homozygous minor genotype (16.5% vs. 7.9%, P = 0.025). In conclusion, our results indicated that the IL-3 rs40401 polymorphism is associated with increased risk of abortion of IVF patients. Future studies with inclusion of other ethnic populations must be conducted to confirm the findings of this study.

Decidual macrophage M1 polarization contributes to adverse pregnancy induced by Toxoplasma gondii PRU strain infection

Recent evidence indicates that macrophages at the maternal-fetal interface adapt to a phenotype characterized by alternative activation (M2 polarization) and exhibit immunosuppressive functions that favor the maintenance of pregnancy. The bias of M2 decidual macrophages toward M1 has been clinically linked to pregnancy-related complications, such as preeclampsia and preterm delivery. The aim of this study was to investigate the effect of Toxoplasma gondii PRU strain infection on the bias of decidual macrophage polarization and its contribution to adverse pregnancy outcomes. A mouse model with adverse pregnancy outcome was established by infection with T. gondii PRU strain and the expression levels of functional molecules in decidual macrophages of mice were measured. The results showed that T. gondii infection caused seriously adverse pregnancy outcome in mice. The placentae of infected mice showed obvious congestion and inflammatory cell infiltration. The expression of CD206, MHC-II, and arginase-1 considered as M2 markers was decreased in decidual macrophages after T. gondii infection, whereas the expression of CD80, CD86, iNOS, and cytokines TNF-α and IL-12 considered as M1 markers was increased. Furthermore, iNOS-positive expression was observed in the decidua basalis of infected mice. Our results indicated that T. gondii infection was responsible for the bias of M2 decidual macrophages toward M1, which changes the immunosuppressive microenvironment at the maternal-fetal interface and contributes to adverse pregnancy outcomes.

Murine embryos exposed to human endometrial MSCs-derived extracellular vesicles exhibit higher VEGF/PDGF AA release, increased blastomere count and hatching rates

Endometrial Mesenchymal Stromal Cells (endMSCs) are multipotent cells with immunomodulatory and pro-regenerative activity which is mainly mediated by a paracrine effect. The exosomes released by MSCs have become a promising therapeutic tool for the treatment of immune-mediated diseases. More specifically, extracellular vesicles derived from endMSCs (EV-endMSCs) have demonstrated a cardioprotective effect through the release of anti-apoptotic and pro-angiogenic factors. Here we hypothesize that EV-endMSCs may be used as a co-adjuvant to improve in vitro fertilization outcomes and embryo quality. Firstly, endMSCs and EV-endMSCs were isolated and phenotypically characterized for in vitro assays. Then, in vitro studies were performed on murine embryos co-cultured with EV-endMSCs at different concentrations. Our results firstly demonstrated a significant increase on the total blastomere count of expanded murine blastocysts. Moreover, EV-endMSCs triggered the release of pro-angiogenic molecules from embryos demonstrating an EV-endMSCs concentration-dependent increase of VEGF and PDGF-AA. The release of VEGF and PDGF-AA by the embryos may indicate that the beneficial effect of EV-endMSCs could be mediating not only an increase in the blastocyst’s total cell number, but also may promote endometrial angiogenesis, vascularization, differentiation and tissue remodeling. In summary, these results could be relevant for assisted reproduction being the first report describing the beneficial effect of human EV-endMSCs on embryo development.

Changes in DNA Methylation from Age 18 to Pregnancy in Type 1, 2, and 17 T Helper and Regulatory T-Cells Pathway Genes

To succeed, pregnancies need to initiate immune biases towards T helper 2 (Th2) responses, yet little is known about what establishes this bias. Using the Illumina 450 K platform, we explored changes in DNA methylation (DNAm) of Th1, Th2, Th17, and regulatory T cell pathway genes before and during pregnancy. Female participants were recruited at birth (1989), and followed through age 18 years and their pregnancy (2011-2015). Peripheral blood DNAm was measured in 245 girls at 18 years; from among these girls, the DNAm of 54 women was repeatedly measured in the first (weeks 8-21, n = 39) and second (weeks 22-38, n = 35) halves of pregnancy, respectively. M-values (logit-transformed β-values of DNAm) were analyzed: First, with repeated measurement models, cytosine-phosphate-guanine sites (CpGs) of pathway genes in pregnancy and at age 18 (nonpregnant) were compared for changes (p ≤ 0.05). Second, we tested how many of the 348 pathway-related CpGs changed compared to 10 randomly selected subsets of all other CpGs and compared to 10 randomly selected subsets of other CD4+-related CpGs (348 in each subset). Contrasted to the nonpregnant state, 27.7% of Th1-related CpGs changed in the first and 36.1% in the second half of pregnancy. Among the Th2 pathway CpGs, proportions of changes were 35.1% (first) and 33.8% (second half). The methylation changes suggest involvement of both Th1 and Th2 pathway CpGs in the immune bias during pregnancy. Changes in regulatory T cell and Th17 pathways need further exploration.

Endometrial BCL6 testing for the prediction of in vitro fertilization outcomes: a cohort study

OBJECTIVE

To evaluate endometrial BCL6 expression as a prognostic biomarker for IVF outcome in women with unexplained infertility (UI) before ET.

DESIGN

Prospective cohort study.

SETTING

University-associated infertility clinic.

PATIENT(S)

Women with UI for >1 year.

INTERVENTION(S)

We studied women with UI who underwent testing for endometrial BCL6, in an LH-timed midluteal phase biopsy and completed an IVF cycle and ET.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate (PR) and live birth rate per transfer was compared for women positive or negative for BCL6 expression. An abnormal BCL6 result was defined by an histologic score (>1.4).

RESULT(S)

Women with normal and abnormal BCL6 and those who conceived or not had similar characteristics. Women with low levels of BCL6 expression had a significantly higher clinical PR (11/17; 64.7%; 95% confidence interval [CI] 41.3-82.6) compared with women with abnormal (high) BCL6 expression (9/52; 17.3%; 95% CI 9.3-30.8). These results yield a relative risk of 0.267 (95% CI 0.13-0.53; P=.0004) for those with normal BCL6 expression, an absolute benefit of 47.4% (95% CI 22.5-72.0). Live birth rate was also significantly higher in women with low BCL6 expression (10/17; 58.8%; 95% CI 36.0-78.4) compared with women with abnormal BCL6 expression (6/52; 11.5%; 95% CI 5.4-23.0). The relative risk was 0.19 (95% CI 0.08-0.45; P=.0002), yielding an absolute benefit of 47.3% (95% CI 21.8-67.8).

CONCLUSION(S)

Aberrant BCL6 expression (histologic score, >1.4) was strongly associated with poor reproductive outcomes in IVF cycles in women with UI.

Characterization of Natural Killer Cells and Cytokines in Maternal Placenta and Fetus of Diabetic Mothers

The present study characterized natural killer cells and cytokines in diabetic mothers, their placenta, and fetus. In the maternal blood from the hyperglycemic groups, the CD16⁺CD56⁻ NK cells increased, whereas that of CD16⁺CD56⁺ decreased in gestational diabetes mellitus [GDM] group. Cord blood from type 2 diabetes [DM-2] showed a higher proportion of CD16⁺CD56⁻ and CD16⁻CD56⁺. The placental extravillous layer of GDM and DM-2 showed an increase of CD16⁺CD56⁻ cells and, irrespective of region, the proportion of CD16⁻CD56⁺ cells was higher in mild gestational hyperglycemia [MGH] and GDM and lower in DM-2. IL-2 was lower in maternal blood and IFN-γ higher in maternal and cord blood from the GDM group. IL-17 was higher in maternal and cord blood from the DM-2 group. The placental extravillous layer of the MGH showed high levels of IL-4, IL-6, IL-10, IL-17, and IFN-γ and low levels of IL-1β and IL-8, whereas the placental villous layer contained high levels of IL-17 and IFN-γ. The GDM group, irrespective of region, showed higher levels of IL-8. The DM-2 group, irrespective of region, placenta showed high levels of TNF-α, IL-17, and IFN-γ. The hyperglycemia produces an inflammatory environment with a high content of inflammatory cytokines and cells expressing CD16⁺.

Macrophage migration inhibitory factor induces phosphorylation of Mdm2 mediated by phosphatidylinositol 3-kinase/Akt kinase: Role of this pathway in decidual cell survival

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway has an anti-apoptotic effect through several downstream targets, which includes activation of the transformed mouse 3T3 cell double-minute 2 (Mdm2) protein, its translocation to the nucleus and degradation of the tumor suppressor p53. We show that Mif, the Macrophage Migration Inhibitory Factor, an important cytokine at the maternal fetal interface in several species, triggers phosphorylation of Mdm2 protein in a PI3K/Akt-dependent manner, thereby preventing apoptosis in cultured mouse decidual cells. Inhibition of Akt and PI3K suppresses the pathway. Mif treatment also changes the nuclear translocation of p53 and interferes with the apoptotic fate of these cells when challenged with reactive oxygen species. In conclusion, an important mechanism has been found underlying decidual cell survival through Akt signaling pathway activated by Mif, suggesting a role for this cytokine in decidual homeostasis and in the integrity of the maternal-fetal barrier that is essential for successful gestation.