Immunological modes of pregnancy loss: inflammation, immune effectors, and stress

Evaluation of the maternal systemic immune system during frozen euploid embryo transfer according to cycle outcome

Infertility affects 15 % of couples in the US, and many turn to assisted reproductive technologies, including in vitro fertilization and subsequent frozen embryo transfer (FET) to become pregnant. This study aimed to perform a broad assessment of the maternal immune system to determine if there are systemic differences on the day of FET in cycles that result in a live birth compared to those that do not. Women undergoing FET of euploid embryos were recruited and blood was collected on the day of FET as well as at early timepoints in pregnancy. Sixty immune and angiogenic proteins were measured in plasma, and gene expression of 92 immune-response related genes were evaluated in peripheral blood mononuclear cells (PBMCs). We found plasma concentrations of interleukin-13 (IL-13) and macrophage derived chemokine (MDC) were significantly lower on the day of FET in cycles that resulted in a live birth. We also found genes encoding C-C chemokine receptor type 5 (CCR5), CD8 subunit alpha (CD8A) and SMAD family member 3 (SMAD3) were upregulated in PBMCs on the day of FET in cycles that resulted in live birth. Measurements of immune mediators from maternal blood could serve as prognostic markers during FET to guide clinical decision making and further our understanding of implantation failure.

Systemic Inflammation Response Index and Systemic Immune-inflammation Index for Prediction of Pregnancy Loss: a Case-control Study

The systemic inflammation response index (SIRI) and systemic immune inflammation index (SII) have recently been investigated as new prognostic markers for obstetric morbidities. However, there are few studies on their predictive role in patients with pregnancy loss. Predicting miscarriages may be useful to support and prevent selected cases.The aim of this study was to investigate the role of SIRI and SII in the prediction of pregnancy loss. A total of 800 patients were included in the retrospective case-control study at a tertiary hospital.Group 1 consisted of 200 patients who had a pregnancy loss for the first time; group 2 consisted of 200 patients with recurrent pregnancy loss; the control group consisted of 400 patients who had a healthy pregnancy. The groups were compared in terms of maternal characteristics, SIRI and SII. Receiver operating characteristic analysis was performed to determine optimal cut-off values for SIRI and SII in predicting pregnancy loss. SIRI and SII were higher in the group with recurrent pregnancy loss than in the control group (p < 0.001).SIRI was higher in the first pregnancy loss group than in the control group (p < 0.001).To predict recurrent pregnancy loss, optimal cut-off values were 1.57 (80% sensitivity, 70% specificity) and 924.12 (74% sensitivity, 57% specificity) for SIRI and SII, respectively. For first pregnancy loss prediction, the optimal cut-off value was 1.38 for SIRI, with 75% sensitivity and 60% specificity. SIRI and SII may be used as inflammatory markers to predict recurrent pregnancy loss. High SIRI values can also help to predict first pregnancy loss.

Beyond Immune Balance: The Pivotal Role of Decidual Regulatory T Cells in Unexplained Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is defined as two or more consecutive pregnancy failures, which brings tremendous stress to women of childbearing age and seriously affects family well-being. However, the reason in about 50% of cases remains unknown and is defined as unexplained recurrent spontaneous abortion (URSA). The immunological perspective in URSA has attracted widespread attention in recent years. The embryo is regarded as a semi-allogeneic graft to the mother. A successful pregnancy requires transition to an immune environment conducive to embryo survival at the maternal-fetal interface. As an important member of regulatory immunity, regulatory T (Treg) cells play a key role in regulating immune tolerance at the maternal-fetal interface. This review will focus on the phenotypic plasticity and lineage stability of Treg cells to illustrate its relationship with URSA.

The Role of Regulatory T Cells and Their Therapeutic Potential in Hypertensive Disease of Pregnancy: A Literature Review

Hypertensive disorders of pregnancy (HDP), including preeclampsia (PE) and gestational hypertension (GH), are major causes of maternal and foetal morbidity and mortality. This review elucidates the role of regulatory T cells (Tregs) in the immunological aspects of HDP and explores their therapeutic potential. Tregs, which play a critical role in maintaining immune homeostasis, are crucial in pregnancy to prevent immune-mediated rejection of the foetus. The review highlights that Tregs contribute to immunological adaptation in normal pregnancy, ensuring foetal acceptance. In contrast, HDP is associated with Treg dysfunction, which is marked by decreased numbers and impaired regulatory capacity, leading to inadequate immune tolerance and abnormal placental development. This dysfunction is particularly evident in PE, in which Tregs fail to adequately modulate the maternal immune response against foetal antigens, contributing to the pathophysiology of the disorder. Therapeutic interventions aiming to modulate Treg activity represent a promising avenue for HDP management. Studies in animal models and limited clinical trials suggest that enhancing Treg functionality could mitigate HDP symptoms and improve pregnancy outcomes. However, given the multifactorial nature of HDP and the intricate regulatory mechanisms of Tregs, the review explores the complexities of translating in vitro and animal model findings into effective clinical therapies. In conclusion, while the precise role of Tregs in HDP is still being unravelled, their central role in immune regulation during pregnancy is indisputable. Further research is needed to fully understand the mechanisms by which Tregs contribute to HDP and to develop targeted therapies that can safely and effectively harness their regulatory potential for treating hypertensive diseases of pregnancy.

Revealing the mechanism of fiber promoting sow embryo implantation by altering the abundance of uterine fluid proteins: A proteomic perspective

Many studies have shown that fiber in the diet plays an important role in improving the reproductive performance of sows, but there is rarely research on the impact of fiber on early embryo implantation. This study used 4D-Label free technology to identify and analyze the effect of the fiber composition in the diet on the protein in the early pregnancy uterine fluid (UF) of sows. The results indicate that ratio of insoluble fibers to soluble fibers (ISF/SF) 4.89 can increase the concentration of progesterone (PROG) and reduce tumor necrosis factorα (TNF-α) concentration in sow UF. In addition, through 4D-Label free, we identified a total of 4248 proteins, 38 proteins abundance upregulated and 283 proteins abundance downregulated in UF. Through enrichment analysis of these differential abundance proteins (DAPs), it was found that these differential proteins are mainly related to the docking of extracellular vesicles, vesicular transport, inflammatory response, and insulin resistance. Therefore, the results of this study reveal the possible mechanism by which fiber improves the reproductive performance of sows, laying a theoretical foundation for future research on the effects of diet on reproduction. SIGNIFICANCE: This study demonstrates the importance of dietary fiber for early embryo implantation in sows. The effect of dietary ISF/SF on early embryo implantation in sows was elucidated from a proteomic perspective through 4D-Label free technology. This study not only has significant implications for improving sow reproductive efficiency, but also provides important theoretical references for studying early miscarriage and reproductive nutrition in human pregnancy.

Investigating the molecular mechanism of traditional Chinese medicine for the treatment of placental syndromes by influencing inflammatory cytokines using the Mendelian randomization and molecular docking technology

Introduction

Placental syndromes, which include pregnancy loss, preterm birth, gestational diabetes mellitus (GDM), and hypertensive disorders in pregnancy (HDP), have a strong association with disorder inflammatory reactions. Nonetheless, the exact causal relationship has not been established. This study aims to investigate the causal relationship between placental syndromes and inflammatory cytokines utilizing Mendelian randomization (MR). Additionally, we examined the interaction between small molecular compounds derived from traditional Chinese medicine and inflammatory cytokines using molecular docking method.

Methods

After obtaining the data of inflammatory cytokines and placental syndromes, as well as establishing single nucleotide polymorphisms (SNPs), we employed the inverse variance weighted (IVW) method to assess the causal relationship. We also accessed the heterogeneity and the horizontal pleiotropy of these data. The "ClusterProfiler" R package was utilized for Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) term analyses. The protein-protein interaction (PPI) network was constructed using STRING database. AutoDock Vina software was used for molecular docking, and Discovery Studio 2019 was used for visualization purposes.

Results

We found that the growth regulated oncogene A (GROA) and interleukin-9 (IL-9) were associated with the development of pregnancy hypertension, whereas interleukin-10 (IL-10) and hepatocyte growth factor (HGF) were linked to the occurrence of preeclampsia. Moreover, there were correlations observed between interleukin-18 (IL-18), IL-10, macrophage colony-stimulating factor (MCSF), and platelet-derived growth factor BB (PDGFbb) in cases of chronic hypertension combined with pregnancy (CHP). Additionally, macrophage migration inhibitory factor (MIF) exhibited a connection with GDM, and TNF related apoptosis inducing ligand (TRAIL) demonstrated a causal relationship with preterm birth. It is plausible to suggest that interleukin-1β (IL-1β) might contribute to the promotion of pregnancy loss. All of the binding free energy values of small molecular compounds with inflammatory cytokines were below -5.0 kcal/mol. Furthermore, all of the RMSD values were less than 2.

Conclusions

GROA, IL-1β, IL-9, IL-10, IL-18, MIF, MCSF, HGF, PDGFbb and TRAIL were found to be causally associated with placental syndromes. Molecular docking analysis revealed that small molecular compounds, such as puerarin, magnolol, atractylenolide I, paeoniflorin, tumulosic acid and wogonin, are closely bound to these inflammatory cytokines.

Chenodeoxycholic Acid Improves Embryo Implantation and Metabolic Health through Modulating Gut Microbiota-Host Metabolites Interaction during Early Pregnancy

Fetus loss in early pregnancy is of major concern to both humans and animals, and this issue is largely influenced by embryo implantation. Chenodeoxycholic acid (CDCA), a primary bile acid, contributes to metabolic improvements and protects against intrahepatic cholestasis of pregnancy. However, the effect of CDCA on embryo implantation during early pregnancy has not been investigated. The present study demonstrated that CDCA administration during early pregnancy improved embryo implantation in sows and rats, thereby improving the pregnancy outcomes of sows. CDCA significantly reduced inflammation, oxidative stress, and insulin resistance. The metabolomics analysis indicated significant differences in the fecal metabolome, especially regarding the level of secondary bile acids, between the control and CDCA-treated sows. CDCA also influenced the serum metabolite profiles in sows, and the serum L-Histidine level was significantly correlated with the abundance of 19 differential fecal metabolites. Importantly, L-Histidine administration improved embryo implantation and metabolic health in rats during early pregnancy. Moreover, CDCA administration during early pregnancy also led to long-term metabolic improvements in sows. Our data indicated that CDCA improved embryo implantation by alleviating inflammation and oxidative stress, improving insulin sensitivity, and modulating the interaction between the gut microbiota and host metabolites. Therefore, CDCA intervention is a potential therapeutic strategy regarding embryo loss during pregnancy.

High mobility group box 1 in women with unexplained recurrent pregnancy loss

OBJECTIVES

To investigate whether high mobility group box 1 (HMGB1) is involved in unexplained recurrent pregnancy loss (uRPL).

METHODS

Plasma levels of HMGB1 were measured by ELISA in non-pregnant women with (n=44) and without (n=53 controls) uRPL. Their platelets and plasma-derived microvesicles (MVs) were also assayed for HMGB1. Endometrial biopsies were taken in selected uRPL (n=5) and control women (n=5) and the tissue expression of HMGB1 was determined by western blot and immunohistochemistry (IHC).

RESULTS

plasma levels of HMGB1 were significantly higher in women with uRPL than in control women. HMGB1 content in platelets and MVs obtained from women with uRPL was significantly higher than that obtained from control women. HMGB1 expression in endometrium was higher in tissues obtained from women with uRPL than in tissues obtained from control women. IHC analysis revealed that HMGB1 is expressed in endometrium with different patterns between uRPL and control women.

CONCLUSIONS

HMGB1 could be involved in uRPL.

The Role of Sirtuin-1 (SIRT1) in the Physiology and Pathophysiology of the Human Placenta

Sirtuins, especially SIRT1, play a significant role in regulating inflammatory response, autophagy, and cell response to oxidative stress. Since their discovery, sirtuins have been regarded as anti-ageing and longevity-promoting enzymes. Sirtuin-regulated processes seem to participate in the most prevalent placental pathologies, such as pre-eclampsia. Furthermore, more and more research studies indicate that SIRT1 may prevent pre-eclampsia development or at least alleviate its manifestations. Having considered this, we reviewed recent studies on the role of sirtuins, especially SIRT1, in processes determining normal or abnormal development and functioning of the placenta.

Myeloid-derived suppressor cells as a potential biomarker for recurrent pregnancy loss and recurrent implantation failure: Increased levels of MDSCs in recurrent reproductive failure

PROBLEM

Recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) represent distinct clinical conditions with established definitions, both of which have been linked to an underlying pro-inflammatory state. This study aimed to explore the levels of monocytic-myeloid-derived suppressor cells (M-MDSCs) and regulatory T cells (TReg ) in a cohort of RPL and RIF women and their potential contribution to RPL and RIF.

METHOD OF STUDY

One hundred and eight non-pregnant women were evaluated: 40 RPL, 41 RIF, and 27 fertile healthy controls (HC). A multiparametric flow cytometry approach was utilized to measure and quantify the frequency of M-MDSCs and TReg cells. Cytokine levels in plasma samples were evaluated through a multiplex assay. M-MDSCs levels were significantly higher in RPL and RIF patients compared to HC.

RESULTS

M-MDSCs levels were significantly higher in RPL (9.4% [7-11.6]) and RIF (8.1% [5.9-11.6]) patients compared to HC (6% [4.2-7.6]). An optimal cut-off of 6.1% for M-MDSCs disclosed a sensitivity of 75.6% and 89.7% and a specificity of 57.7% and 57.7% in RIF and RPL groups, respectively. A significant negative correlation was observed between M-MDSCs and TReg (p = .002, r = -.51).

CONCLUSIONS

Our preliminary data allowed us to build a predictive model that may aid as a potential diagnostic tool in the clinic. These findings could provide a better understanding of these pathologies and a better definition of patients that could benefit from personalized treatments to promote pregnancy. Additional exploration and confirmation in distinct study groups are needed to fully assess the diagnostic capabilities of this biomarker.

OX40 (CD134) Expression on T Regulatory Cells Is Related to Serious Hypertensive Disorders in Pregnancy

Hypertension is one of the leading causes of morbidity and mortality among women related to pregnancy, childbirth and the postpartum period. The pathogenesis of gestational hypertension is complex and still not fully understood. The aim of this study was to assess the population of circulating CD4+CD25+FoxP3+ cells and its differentiation in terms of OX40 expression in two forms of hypertension: isolated hypertension developing after the 20th week of pregnancy and pre-eclampsia. The study included a group of 60 patients with hypertension and 48 healthy controls. The analysis of the percentage of Tregs was performed by flow cytometry. There was no difference in the percentage of peripheral lymphocytes between the groups. In the group of women with preeclampsia compared to the group with gestational hypertension, significantly higher percentages of CD4+CD25+FoxP3+ cells (p = 0.03) and percentages of CD4+CD25+FoxP3+ cells expressing the OX40 antigen (p = 0.001) were observed. OX40 expression on Tregs seems to be related to more serious type of hypertensive disorders in pregnant women.

Comprehensive molecular expression profiling of SARS-CoV-associated factors in the endometrium across the menstrual cycle and elevated susceptibility in women with recurrent pregnancy loss

Objective: To evaluate the dynamic expression profiling alterations of SARS-CoV-2-associated molecules within the fertile human endometrium throughout the menstrual cycle. Furthermore, to explore the inherent vulnerability of the endometrium to SARS-CoV-2 infection among women experiencing recurrent pregnancy failure, including both recurrent implantation failures (RIF) and recurrent pregnancy losses (RPL). Method: The present study employed multiple datasets to investigate the expression patterns of SARS-CoV-2-associated genes. Firstly, a single-cell RNA-sequencing dataset comprising endometrial samples from 19 healthy women across the menstrual cycle was utilized. Additionally, two microarray datasets encompassing 24 women with RIF, and 24 women with RPL during the peri-implantation phase were included. To complement these analyses, immunohistochemical (IHC) staining was performed on endometrial samples collected from 30 women with RIF, 30 women with RPL, and 20 fertile controls recruited specifically during the implantation period. Results: The investigation revealed a moderate expression percentage of CTSL (22%), TMPRSS4 (15%), FURIN (16%) and MX1 (9%) in endometrium. Conversely, the expression percentages of ACE2 (1%) and TMPRSS2 (4%) were relatively low. Notably, the expression of BSG exhibited an increment towards the window of implantation, reaching its peak during the middle secretary phase. Furthermore, a significant reduction (p < 0.05) in TMPRSS2 expression was observed in the RIF group compared to the control group. While the expression of BSG was significantly increased (p < 0.05) in the RPL group, findings that were corroborated by the IHC staining results. Conclusion: The findings of this study indicate a noteworthy upregulation of BSG expression in the endometrium of women with RPL. These results suggest an augmented susceptibility of endometrium to SARS-CoV-2 infection, potentially contributing to unfavorable pregnancy outcomes.

Cyclophilin A as a Pro-Inflammatory Factor Exhibits Embryotoxic and Teratogenic Effects during Fetal Organogenesis

The precise balance of Th1, Th2, and Th17 cytokines is a key factor in successful pregnancy and normal embryonic development. However, to date, not all humoral factors that regulate and influence physiological pregnancy have been completely studied. Our data here pointed out cyclophilin A (CypA) as the adverse pro-inflammatory factor negatively affecting fetal development and associated with pregnancy complications. In different mouse models in vivo, we demonstrated dramatic embryotoxicity and teratogenicity of increased CypA levels during pregnancy. Using generated transgenic models, we showed that CypA overexpression in fetal tissues induced the death of all transgenic fetuses and complete miscarriage. Administration of recombinant human CypA in a high dose to pregnant females during fetal organogenesis (6.5-11.5 dpc) exhibited teratogenic effects, causing severe defects in the brain and bone development that could lead to malformations and postnatal behavioral and cognitive disorders in the offspring. Embryotoxic and teratogenic effects could be mediated by CypA-induced up-regulation of M1 macrophage polarization via activation of the STAT1/3 signaling pathways. Here, we propose secreted CypA as a novel marker of complicated pregnancy and a therapeutic target for the correction of pregnancy complications.

Sequential disruptions to inflammatory and angiogenic pathways and risk of spontaneous preterm birth in Malawian women

Preterm birth is a leading cause of death in children under five years of age. We hypothesized that sequential disruptions to inflammatory and angiogenic pathways during pregnancy increase the risk of placental insufficiency and spontaneous preterm labor and delivery. We conducted a secondary analysis of inflammatory and angiogenic analytes measured in plasma samples collected across pregnancy from 1462 Malawian women. Women with concentrations of the inflammatory markers sTNFR2, CHI3L1, and IL18BP in the highest quartile before 24 weeks gestation and women with anti-angiogenic factors sEndoglin and sFlt-1/PlGF ratio in the highest quartile at 28-33 weeks gestation had an increased relative risk of preterm birth. Mediation analysis further supported a potential causal link between early inflammation, subsequent angiogenic dysregulation detrimental to placental vascular development, and earlier gestational age at delivery. Interventions designed to reduce the burden of preterm birth may need to be implemented before 24 weeks of gestation.

Fetal-maternal interactions during pregnancy: a 'three-in-one' perspective

A successful human pregnancy requires the maternal immune system to recognize and tolerate the semi-allogeneic fetus, allowing for appropriate trophoblasts invasion and protecting the fetus from invading pathogens. Therefore, maternal immunity is critical for the establishment and maintenance of pregnancy, especially at the maternal-fetal interface. Anatomically, the maternal-fetal interface has both maternally- and fetally- derived cells, including fetal originated trophoblasts and maternal derived immune cells and stromal cells. Besides, a commensal microbiota in the uterus was supposed to aid the unique immunity in pregnancy. The appropriate crosstalk between fetal derived and maternal originated cells and uterine microbiota are critical for normal pregnancy. Dysfunctional maternal-fetal interactions might be associated with the development of pregnancy complications. This review elaborates the latest knowledge on the interactions between trophoblasts and decidual immune cells, highlighting their critical roles in maternal-fetal tolerance and pregnancy development. We also characterize the role of commensal bacteria in promoting pregnancy progression. Furthermore, this review may provide new thought on future basic research and the development of clinical applications for pregnancy complications.

Inhibition of TMUB1 blocks apoptosis and NF-κB pathway-mediated inflammation in recurrent spontaneous abortion

INTRODUCTION

Approximately 50% of cases with recurrent spontaneous abortion (RSA) have unexplained etiology. Aberrant expression of transmembrane and ubiquitin-like domain containing 1 (TMUB1) is closely related to a series of diseases, including RSA. However, the function and underlying mechanism of TMUB1 in the occurrence of RSA has not been described.

METHODS

TMUB1 expression was detected in the placental villous tissues of 30 women with normal miscarriages and 12 women with RSA. The pregnant mice were injected intraperitoneally with lipopolysaccharide (LPS) to induce abortion. Human chorionic trophoblast cells were treated with LPS. Pathological analysis of placental tissues was performed by hematoxylin and eosin staining.

RESULTS

TMUB1 was highly expressed in the placental villous tissues of RSA patients compared to the patients who underwent induced abortions. After LPS administration, the mice exhibited high embryo absorption and pathological alterations, as well as presented an increase in inflammation and apoptosis (the etiology of RSA induction) in placental tissues. Moreover, the upregulated expression of TMUB1 was also found in placental tissues of LPS-induced mice, and further investigation showed that TMUB1 deficiency blocked embryo loss as well as inhibited apoptotic rate and inflammation after LPS activation. Furthermore, we found that the loss of TMUB1 suppressed the phosphorylation of IkappaB kinase (IKK) α/β and attenuated cytoplasmic-nuclear translocation of nuclear factor-κB (NF-κB) p65 in LPS-induced cells.

CONCLUSION

Our results indicate that TMUB1 may involve in the modulation of apoptosis and NF-κB pathway-mediated inflammation in RSA. Therefore, TMUB1 may develop as a potential biomarker for RSA treatment.

Should the Treatment of Patients with Repeated Embryo Implantation Failure Be Adapted as a Function of the Endometrial Cytokine Profile? A Single-Center Experience

Repeated embryo implantation failures (RIF) is a source of distress and frustration for patients and clinicians alike. Today's approaches for treating RIF are largely empirical and have limited effectiveness. The main causes of RIF are poor endometrial receptivity and poor-quality embryos. Recent studies have suggested the involvement of immune dysregulation due to an imbalance between T-helper (Th) 1 and Th2 cytokines; this opens up perspectives for treating women with RIF and increasing the implantation rate. We conducted an interventional, longitudinal, prospective cohort study of the impact of correcting the cytokine imbalance on the clinical pregnancy rate in women with RIF. Seventy-seven women with RIF underwent an endometrial biopsy during the implantation window. The cytokine profile was evaluated by studying the activation and maturation of uterine natural killer (uNK) cells, the IL-15/Fn-14 mRNA ratio (a biomarker of uNK activation/maturation), and the IL-18/TWEAK mRNA ratio (a marker of angiogenesis and the Th1/Th2 balance). Personalized treatment was initiated for women with an abnormal endometrial cytokine profile (hyper-activation or hypo-activation). We documented the clinical pregnancy rate after subsequent embryo transfers. In total, 72.7% (56/77) of patients had an abnormal endometrial cytokine profile (hyper-activation in 68.8% (n = 53) and hypo-activation in 3.9% (n = 3). After treatment (or not) as a function of the endometrial profile, the overall clinical pregnancy rate was 30.2%. Our results indicated a potential positive effect of appropriate treatment on the ongoing pregnancy rate in women with RIF, despite the small number of cases analyzed. The results must now be validated in randomized studies with larger numbers of well-characterized patients. By applying a previously published decision tree, this treatment approach could be implemented in clinics worldwide.

A prospective study comparing the inflammation-related cytokine and chemokine profile from the day of blastocyst transfer to 7 weeks of gestation between pregnancies that did or did not result in a miscarriage

The dynamics of maternal immunomodulation is essential in early pregnancy. In our previous study, successful implantation is characterized by a transient increase of pro-inflammatory cytokines followed by a switch to an anti-inflammatory state in peripheral blood around 3-6 days after embryo transfer (ET). In this study, we aimed to extend the time points to compare the cytokine and chemokine profiles between women who did or did not subsequently miscarry. We utilized precisely timed serum samples on the day of ET and 3, 6, 9, 16, 23 and 30 days after ET in women undergoing single blastocyst transfer. Our analysis revealed a significant alteration in cytokine profile after day ET+ 9 between the two groups. Regarding pro-inflammatory cytokine profile, there was a significant increase in IL-17 on days ET+ 16, + 23, and + 30 (50.60 ± 9.97 vs 37.09 ± 3.25, 53.20 ± 8.13 vs 36.51 ± 3.34, 57.06 ± 8.83 vs 33.04 ± 3.11 pg/mL), TNF-α on days ET+ 23 and + 30 (73.90 ± 12.42 vs 50.73 ± 3.55, 74.16 ± 12.46 vs 46.59 ± 3.21 pg/mL), IFN-γ on day ET+ 30 (69.52 ± 13.19 vs 42.28 ± 7.76 pg/mL) in women who miscarried compared to women who had a live birth. In contrast, the concentrations of anti-inflammatory cytokines IL-10 on days ET+ 23 and + 30 (26.23 ± 2.11 vs 38.30 ± 4.64, 23.77 ± 2.06 vs 39.16 ± 4.99 pg/mL) and TGF-β1 on day ET+ 30 (20.30 ± 1.25 vs 23.81 ± 0.88 ng/mL) were significantly decreased in women who miscarried compared to women who had a live birth. While for the chemokine profile, there was no significant alteration observed between the two groups across all the time points. These findings suggest that a sustained anti-inflammatory milieu is concomitant with the maintenance of early pregnancy, while the remarkable pro-inflammatory shift as early as day ET+ 16 in women who subsequently miscarried was observed before the diagnosis of miscarriage.

Changes in the T-helper 1 and 2 cell populations during pregnancy in tacrolimus-treated women with repeated implantation failure and recurrent pregnancy loss

Tacrolimus has received considerable attention as a treatment approach for infertility associated with maternal-foetal immune abnormalities, such as repeated implantation failure (RIF) and recurrent pregnancy loss (RPL). This study examined the changes in T-helper (Th) 1 and 2 cell populations during pregnancy in peripheral blood of tacrolimus-treated RIF patients who delivered a liveborn infant from August 2012 to February 2020 at the National Centre for Child Health and Development. A total of 58 eligible study subjects were divided into two groups according to the presence of a history of RPL: (i) RIF-alone group (n = 31); and (ii) RIF-plus-RPL group (n = 27). In a flow cytometric analysis, the Th1/Th2 cell ratios were significantly higher before pregnancy than after pregnancy, and during the first trimester than the second trimester in the RIF-alone group (p = 0.0071 and p = 0.0087, respectively). However, no significant differences were present in the RIF-plus-RPL group. Although the Th1 immunity was suppressed under tacrolimus treatment in both groups, a delayed reduction in the Th1 cell percentage after initiation of treatment was observed in the RIF-plus-RPL group. In conclusion, the cellular immune alterations in tacrolimus-treated patients with RIF were different depending on the presence or absence of a history of RPL.

Pregnancy stage-dependent modulation of neutrophil function may impact embryo survivability and pregnancy outcome in crossbred cows

Pregnancy is a complicated physiological process that involves synchronized coordination between immune and endocrine systems. Neutrophils have been suggested as a critical immune cell for embryo implantation and pregnancy maintenance. The present study was conducted to evaluate the dynamic changes in the mRNA expressions of the cluster of designation (CD11b, CD31, CD44 and CD62L) molecules and interferon-stimulated genes (ISG15, MX1 and OAS1) in blood neutrophils throughout pregnancy in dairy cows and correlate them with the outcome of pregnancy. Blood samples were taken from negative control (NC) group, and non-pregnant (NP) group at the time of artificial insemination (AI, day zero) and on days 10, 14, 16, 18, and 21 post-AI. In pregnant (P) cows, samples were taken as described above and after every 30 days until the time of parturition. In aborted cows, samples were collected until the time of the abortion. Comparison between pregnant, non-pregnant and aborted cows revealed that the expression of CD molecules increased (p < 0.05) on days 14, 16, 18 and 21 post-AI only in NP cows as compared to other groups. Although the expression of CD molecules remained constant throughout the study period in pregnant and aborted cows, the expression of CD11b, CD31 and CD62L increased (p < 0.05) on the day of abortion and parturition. Unlike CD molecules, the expression of CD44 decreased significantly (p < 0.05) at the time of abortion. There was a significant (p < 0.05) increase in the expression of interferon-stimulated genes including MX1, OAS1 and ISG15 during the peri-implantation period in pregnant cows, and at the time of abortion in aborted cows. However, the expression of ISGs was lower (p < 0.05) in non-pregnant cows as compared to the other groups. The results revealed the critical role played by neutrophils during pregnancy and form the basis to unravel the underlying mechanism for neutrophil associated immunological infertility in bovines.

Maternal obesity and the impact of associated early-life inflammation on long-term health of offspring

The prevalence of obesity is increasingly common in the United States, with ~25% of women of reproductive age being overweight or obese. Metaflammation, a chronic low grade inflammatory state caused by altered metabolism, is often present in pregnancies complicated by obesity. As a result, the fetuses of mothers who are obese are exposed to an in-utero environment that has altered nutrients and cytokines. Notably, both human and preclinical studies have shown that children born to mothers with obesity have higher risks of developing chronic illnesses affecting various organ systems. In this review, the authors sought to present the role of cytokines and inflammation during healthy pregnancy and determine how maternal obesity changes the inflammatory landscape of the mother, leading to fetal reprogramming. Next, the negative long-term impact on offspring’s health in numerous disease contexts, including offspring’s risk of developing neuropsychiatric disorders (autism, attention deficit and hyperactive disorder), metabolic diseases (obesity, type 2 diabetes), atopy, and malignancies will be discussed along with the potential of altered immune/inflammatory status in offspring as a contributor of these diseases. Finally, the authors will list critical knowledge gaps in the field of developmental programming of health and diseases in the context of offspring of mothers with obesity, particularly the understudied role of hematopoietic stem and progenitor cells.

Differential proteomics of placentas reveals metabolic disturbance and oxidative damage participate yak spontaneous miscarriage during late pregnancy

Background

High spontaneous miscarriage rate in yak, especially during late pregnancy, have caused a great economic loss to herdsmen living in the Qinghai-Tibet plateau. However, the mechanism underlying spontaneous miscarriage is still poorly understood. In the present study, placenta protein markers were identified to elucidate the pathological reasons for yak spontaneous miscarriage through isobaric tags for relative and absolute quantification (iTRAQ) proteomic technology and bioinformatic approaches.

Results

Subsequently, a total of 415 differentially expressed proteins (DEPs) were identified between aborted and normal placentas. The up-regulated DEPs in the aborted placentas were significantly associated with “spinocerebellar ataxia”, “sphingolipid signalling”, “relaxin signalling”, “protein export”, “protein digestion and absorption” and “aldosterone synthesis and secretion” pathway. While the down-regulated DEPs in the aborted placentas mainly participated in “valine, leucine and isoleucine degradation”, “PPAR signalling”, “peroxisome”, “oxidative phosphorylation”, “galactose metabolism”, “fatty acid degradation”, “cysteine and methionine metabolism” and “citrate cycle” pathway.

Conclusions

The results implied that the identified DEPs could be considered as placental protein markers for yak miscarriage during late pregnancy, and biomacromolecule metabolic abnormality and oxidative damage might be responsible for the high spontaneous miscarriage rate in yak. These findings provide an important theoretical basis for deciphering the pathologic mechanism of late spontaneous miscarriage in yak.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03354-w.

Triclosan activates c-Jun/miR-218-1-3p/SLC35C1 signaling to regulate cell viability, migration, invasion and inflammatory response of trophoblast cells in vitro

BACKGROUND

Spontaneous abortion is considered as the commonest complication of pregnancy. Triclosan (TCS) is an antimicrobial agent, which participates in the process of multiple human diseases, including spontaneous abortion. Our study aimed to evaluate the effect of TCS on spontaneous abortion and disclose the possible regulatory mechanism in vitro.

RESULTS

RT-qPCR analyzed that miR-218-1-3p derived from abortion-associated factor slit guidance ligand 2 (SLIT2) was up-regulated in trophoblast cells under TCS treatment. Supported by western blot analysis, functional experiments demonstrated that miR-218-1-3p overexpression impeded the proliferation, migration and invasion while exacerbating the inflammatory response of trophoblast cells. Moreover, mechanism assays revealed that TCS modulated c-Jun production to promote MIR218-1 transcription and enhance miR-218-1-3p expression. Moreover, solute carrier family 35 member C1 (SLC35C1) was validated as a target gene of miR-218-1-3p, and miR-218-1-3p was sustained to negatively modulate SLC35C1 expression in trophoblast cells. Rescue assays validated the role of TCS/miR-218-1-3p/SLC35C1 axis in regulating the viability, migration, invasion and inflammatory response of trophoblast cells.

CONCLUSIONS

TCS regulated miR-218-1-3p/SLC35C1 axis to modulate the proliferation, migration, invasion and inflammatory response of trophoblast cells in vitro, which might provide novel insights for spontaneous abortion prevention.

Immune determinants of endometrial receptivity: a biological perspective

Immune cells are essential for endometrial receptivity to embryo implantation and early placental development. They exert tissue-remodeling and immune regulatory roles-acting to promote epithelial attachment competence, regulate the differentiation of decidual cells, remodel the uterine vasculature, control and resolve inflammatory activation, and suppress destructive immunity to paternally inherited alloantigens. From a biological perspective, the endometrial immune response exerts a form of "quality control"-it promotes implantation success when conditions are favorable but constrains receptivity when physiological circumstances are not ideal. Women with recurrent implantation failure and recurrent miscarriage may exhibit altered numbers or disturbed function of certain uterine immune cell populations-most notably uterine natural killer cells and regulatory T cells. Preclinical and animal studies indicate that deficiencies or aberrant activation states in these cells can be causal in the pathophysiological mechanisms of infertility. Immune cells are, therefore, targets for diagnostic evaluation and therapeutic intervention. However, current diagnostic tests are overly simplistic and have limited clinical utility. To be more informative, they need to account for the full complexity and reflect the range of perturbations that can occur in uterine immune cell phenotypes and networks. Moreover, safe and effective interventions to modulate these cells are in their infancy, and personalized approaches matched to specific diagnostic criteria will be needed. Here we summarize current biological understanding and identify knowledge gaps to be resolved before the promise of therapies to target the uterine immune response can be fully realized.

Chromosomal Copy Number Variation Analysis in Pregnancy Products from Recurrent and Sporadic Miscarriage Using Next-Generation Sequencing

Chromosomal abnormality is one of the causes of fetal miscarriage. The potential differences of fetal chromosomal abnormalities in sporadic miscarriage (SM) and recurrent miscarriage (RM) remain unclear. The purpose of this study was to investigate copy number variations (CNVs) in SM and RM to provide useful genetic guidance for pregnancy and prenatal diagnosis. Four hundred eight samples of aborted fetuses were analyzed by CNV sequencing, and further functional enrichment analysis was performed. Chromosomal abnormalities were identified in 218 (53.4%) fetuses. There were 62 cases (15.2%) with structural chromosomal abnormalities, including 41 with VUS CNVs, 8 with pathogenic CNVs (pCNVs), and 5 with likely pCNVs. Duplications or deletions of 7p22, 8p22, 8p23, and Xp22.31 were significantly more common in RM cases and therefore believed to be related to RM. A total of 289 genes were identified, and 29 different functions were enriched as potential RM candidate genes and functions, which were mainly concentrated in 4 functional categories: chemokines and chemotaxis, protease activity and protein modification, defense response to bacterial and fungal infections, and immune response. The results of this study may improve our understanding of the etiology of RM and contribute to the establishment of a population-based genetic marker information for RM.

Immunological parameters of recurrent miscarriages among women in Thi-Qar province

Recurrent miscarriage (RM) is defined as the loss of pregnancy three or more consecutive times in the first and second trimester, which in some cases occurs due to immune abnormalities. This study aimed to assess some immunological parameters in women with recurrent miscarriages, including the level of antiphospholipid antibody (APA), anticardiolipin (ACA), antinuclear antibody (ANA), complement C3 and C4, and interleukine-3 (IL-3). We included 100 patients together with 100 healthy women as a control. ELIZA was used to measure some types of autoantibodies. APA and ACA significantly increased (P≤0.05) in patients compared to control. In addition, 29% of the patients were positive for antinuclear antibodies (ANA), while the control subjects had negative results for these autoantibodies. Regarding the complement, the serum levels of C3 and C4 were significantly elevated in the serum level of patients when compared to the control group, but in treated patients (heparin and low-dose aspirin), the levels of the complement (C3 and C4) showed a significant decrease in patients compared to total controls. Cytokine level (IL-3) significantly decreased in untreated patients 302.78 pg/ml compared to treated patients (741.57 pg/ml). Antiphospholipid antibodies are more prevalent among women with recurrent miscarriages and are also believed to be the result of abnormal autoimmune activation.

Progesterone: A Unique Hormone with Immunomodulatory Roles in Pregnancy

Progesterone is well known for its numerous endocrinologic roles in pregnancy but is also endowed with fascinating immunomodulatory capabilities. It can downregulate the induction of inflammatory reactions, the activation of immune cells and the production of cytokines, which are critical mediators of immune responses. These features appear to be critical to the success of pregnancy, given the ability of maternal immune reactivity to interfere with pregnancy and to contribute to several pregnancy complications. This review summarizes the contribution of maternal immune effectors in general, and cytokines in particular, to pregnancy complications such as recurrent miscarriage, pre-eclampsia and preterm labor; it describes the promise offered by supplementation with progesterone and the oral progestogen dydrogesterone, as well as the progesterone-induced blocking factor in the prevention and/or treatment of these serious complications.

Transcriptome study of receptive endometrium in overweight and obese women shows important expression differences in immune response and inflammatory pathways in women who do not conceive

Obesity and being overweight are growing worldwide health problems that also affect women of reproductive age. They impair women’s fertility and are associated with lower IVF success rates. The mechanism by which increased body weight disrupts fertility has not yet been established. One possibility is that it affects the process of embryo implantation on the endometrial level. The purpose of our study was to determine the differences in enriched biological pathways in the endometrium of overweight and obese women undergoing IVF procedures. For this purpose, 14 patients (5 pregnant, 9 non-pregnant) were included in the study. Endometrial samples were obtained during the window of implantation and RNA sequencing was performed. There were no differences in general patient’s and IVF cycle characteristics between pregnant and non-pregnant women. In the endometrial samples of women who did not conceive, pathways related to the immune response, inflammation, and reactive oxygen species production were over-expressed. Our findings show that the reason for implantation failure in overweight and obese women could lie in the excessive immune and inflammatory response at the endometrial level.

Mesenchymal stem cell therapy attenuates complement C3 deposition and improves the delicate equilibrium between angiogenic and anti-angiogenic factors in abortion-prone mice

Immunological disorders are one of the main causes of recurrent spontaneous abortions (RSA). A rapidly expanding body of evidence indicates that excessive activation of the complement system is critically involved in the development of miscarriages. In the CBA/J × DBA/2 murine model of recurrent miscarriage, exaggerated and unrestrained complement activation is reported to be the underlying cause of angiogenic factor imbalance and persistent inflammation. We have previously shown that mesenchymal stem cell (MSC) therapy can significantly reduce the abortion rate in abortion-prone mice through regulating the feto-maternal immune response. In the present study, we hypothesized that MSCs might improve the balance of angiogenic factors at the feto-maternal unit of CBA/J × DBA/2 mice by restraining complement activation and deposition. To explore this hypothesis, autologous adipose tissue-derived mesenchymal stem cells (AD-MSCs) were administered intra-peritoneally to abortion-prone mice on the 4.5th day of gestation. Control mice received PBS as vehicle. On day 13.5 of pregnancy, deposition of the complement component C3 and expression levels of Crry, CFD (adipsin), VEGF, PlGF and FLT-1 were measured at the feto-maternal interface by immunohistochemistry and real-time PCR, respectively. Decidual cells were also cultured in RPMI 1640 medium for 48 h and VEGF and sFLT-1 protein levels were quantified in supernatants using enzyme-linked immunosorbent assay (ELISA). Our results indicated that MSC therapy significantly reduced C3 deposition and adipsin transcription in the fetal-maternal interface of abortion-prone mice. Furthermore, administration of MSCs robustly upregulated the mRNA expression levels of Crry, VEGF, PlGF and FLT-1 in the placenta and decidua of CBA/J × DBA/2 mice. Consistently, the in vitro results demonstrated that decidual cells obtained from MSC-treated dams produced increased concentrations of VEGF in culture supernatants, with concomitant decreased levels of sFLT-1 protein. Here, we show for the first time that adoptive transfer of MSCs rectifies the disturbed balance of angiogenic factors observed at the feto-maternal unit of CBA/J × DBA/2 mice, in part at least, through inhibiting excessive complement activation and promoting the production of angiogenic factors. Collectively, these alterations seem to play a pivotal role in reducing the abortion rate and improving the intrauterine condition for the benefit of the fetus.

Association of Maternal History of Spontaneous Abortion and Stillbirth With Risk of Congenital Heart Disease in Offspring of Women With vs Without Type 2 Diabetes

IMPORTANCE

The associations of maternal history of spontaneous abortion (SA) and stillbirth with congenital heart disease (CHD) remain elusive.

OBJECTIVE

To evaluate the associations of maternal history of pregnancy loss with CHD in offspring and the role of maternal type 2 diabetes.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study included singleton live offspring born between January 1, 1977, and December 31, 2016, identified through Danish national health registries. Statistical analysis was performed from October 1, 2019, through September 1, 2021.

EXPOSURES

Maternal history of SA, with frequency varying from 1 or 2 to 3 or more episodes, and maternal history of single and multiple stillbirths.

MAIN OUTCOMES AND MEASURES

Overall CHD identified by hospital diagnosis. Cox proportional hazard regression was used to estimate the hazard ratio (HR) of CHD. Diabetes was evaluated as a potential confounder and a potential effect modifier.

RESULTS

Among 1 642 534 included offspring (mean [SD] age, 14.11 [8.39] years; 843 265 male [51.35%]), 246 669 (15.02%) were born to mothers with a history of SA and 9750 (0.59%) were born to mothers with a history of stillbirth. The HRs of CHD were 1.16 (95% CI, 1.13-1.20) for offspring with a maternal history of SA and 1.49 (95% CI, 1.32-1.68) for offspring with a maternal history of stillbirth. Significant dose-response associations were observed among offspring with a maternal history of 3 or more episodes of SA (HR, 1.60; 95% CI, 1.39-1.84) and those with maternal history of multiple stillbirths (HR, 2.75; 95% CI, 1.63-4.65). If only inpatient CHD cases were included, the risk of CHD was higher than that found in the main analysis, with HRs of 1.24 (95% CI, 1.19-1.30) for maternal history of SA and 1.78 (95% CI, 1.51-2.11) for maternal history of stillbirth. The observed associations were strengthened by maternal prepregnancy type 2 diabetes (HR for maternal history of SA, 1.65 [95% CI, 1.37-1.97]; HR for maternal history of stillbirth, 1.74 [95% CI, 1.06-2.85]).

CONCLUSIONS AND RELEVANCE

These findings suggest that offspring born to mothers with a previous SA or stillbirth, especially multiple episodes, or with prepregnancy type 2 diabetes were at a higher risk of being diagnosed with CHD. These findings may help identify women at increased risk in whom detailed fetal heart assessment may be cost-effective and highlight the importance of screening for type 2 diabetes in women of reproductive age.

Biomolecular Markers of Recurrent Implantation Failure-A Review

Currently, infertility affects 8–12% of reproductive age couples worldwide, a problem that also affects women suffering from recurrent implantation failure (RIF). RIF is a complex condition resulting from many physiological and molecular mechanisms involving dynamic endometrium–blastocyst interaction. The most important are the endometrial receptivity process, decidualization, trophoblast invasion, and blastocyst nesting. Although the exact multifactorial pathogenesis of RIF remains unclear, many studies have suggested the association between hormone level imbalance, disturbances of angiogenic and immunomodulatory factors, certain genetic polymorphisms, and occurrence of RIF. These studies were performed in quite small groups. Additionally, the results are inconsistent between ethnicities. The present review briefly summarizes the importance of factors involved in RIF development that could also serve as diagnostic determinants. Moreover, our review could constitute part of a new platform for discovery of novel diagnostic and therapeutic solutions for RIF.

COVID-19 and miscarriage: From immunopathological mechanisms to actual clinical evidence

The association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the first half of pregnancy and pregnancy loss is still unknown. Infections by other coronaviruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV), appear to increase the risk of miscarriage. The purpose of this study is to assess whether SARS-CoV-2 infection increases the risk of miscarriage. Firstly, a narrative review of the literature on animal and human studies was performed to analyze the immunopathological mechanisms of SARS-CoV-2 infection during preconception and early pregnancy, by which it may increase the risk of miscarriage. Secondly, a systematic review/meta-analysis of studies was conducted to assess the prevalence of miscarriage in COVID-19 patients diagnosed during pregnancy. Meta-analysis of proportions was used to combine data, and pooled proportions were reported. Seventeen case series and observational studies and 10 prevalence meta-analyses were selected for the review. The estimate of the overall miscarriage rate in pregnant women with COVID-19 was 15.3 % (95 % CI 10.94-20.59) and 23.1 (95 % CI 13.17-34.95) using fixed and random effect models, respectively. Based on the data in the current literature, the miscarriage rate (<22 weeks gestation) in women with SARS-CoV-2 infection is in the range of normal population. Well-designed studies are urgently needed to determine whether SARS-CoV-2 infection increases the risk of miscarriage during periconception and early pregnancy.

Reproductive outcomes of women with recurrent pregnancy losses and repeated implantation failures are significantly improved with immunomodulatory treatment

This study investigated if immunomodulatory treatment improves the in-vitro fertilization (IVF) success rates of women with two or more recurrent pregnancy losses (RPL) and repeated implantation failures (RIF) with cellular immune abnormalities and thrombophilia. We performed a retrospective cohort study of 197 RPL patients who received immunomodulatory and anticoagulation treatment undergoing IVF cycles (fresh or frozen embryo transfer). Patients were divided into four groups; Group 1: women with RPL but without RIF, Group 2: women with RPL and RIF (≥3), Group 3: women with RPL after IVF cycles (>2) and without RIF, and Group 4: women with RPL after IVF cycles and RIF. Patients received immunomodulatory treatment with prednisone-only or prednisone and intravenous immunoglobulin G (IVIG) and anticoagulation treatment with low molecular weight heparin and low dose aspirin. IVF success rates of study groups were compared to those of the historical controls. The pregnancy rate of IVF cycles with immunomodulatory treatment was significantly increased in all patients (48.2 % vs. 33.0 %, P < 0.001), Group 1 (54.2 % vs. 30.5 %, P < 0.005) and Group 2 (33.3 % vs. 11.0 %, P < 0.005) as compared to historical controls. The live birth rates per ET cycle were significantly improved for all patients (1.8 % vs. 39.6 %, P < 0.001), and study groups compared to their historical controls (Group 1, 43.1 % vs. 0 %; Group 2, 33.3 % vs. 2.5 %; Group 3, 45.5 % vs. 2.3 %; and Group 4, 16.7 % vs. 1.2 %, P < 0.001, respectively). Immunomodulatory and anticoagulation treatment significantly improved the reproductive outcomes of IVF cycles in women with a history of RPL and/or RIF of immune etiologies.

The Role and Function of Regulatory T Cells in Toxoplasma gondii-Induced Adverse Pregnancy Outcomes

Infection with Toxoplasma gondii (T. gondii) during the pregnant period and its potentially miserable outcomes for the fetus, newborn, and even adult offspring continuously occur worldwide. People acquire infection through the consumption of infected and undercooked meat or contaminated food or water. T. gondii infection in pregnant women primarily during the gestation causes microcephaly, mental and psychomotor retardation, or death. Abnormal pregnancy outcomes are mainly associated with regulatory T cell (Treg) dysfunction. Tregs, a special subpopulation of T cells, function as a vital regulator in maintaining immune homeostasis. Tregs exert a critical effect on forming and maintaining maternal-fetal tolerance and promoting fetal development during the pregnancy period. Forkhead box P3 (Foxp3), a significant functional factor of Tregs, determines the status of Tregs. In this review, we summarize the effects of T. gondii infection on host Tregs and its critical transcriptional factor, Foxp3.

Botryllus schlosseri as a Unique Colonial Chordate Model for the Study and Modulation of Innate Immune Activity

Understanding the mechanisms that sustain immunological nonreactivity is essential for maintaining tissue in syngeneic and allogeneic settings, such as transplantation and pregnancy tolerance. While most transplantation rejections occur due to the adaptive immune response, the proinflammatory response of innate immunity is necessary for the activation of adaptive immunity. Botryllus schlosseri, a colonial tunicate, which is the nearest invertebrate group to the vertebrates, is devoid of T- and B-cell-based adaptive immunity. It has unique characteristics that make it a valuable model system for studying innate immunity mechanisms: (i) a natural allogeneic transplantation phenomenon that results in either fusion or rejection; (ii) whole animal regeneration and noninflammatory resorption on a weekly basis; (iii) allogeneic resorption which is comparable to human chronic rejection. Recent studies in B. schlosseri have led to the recognition of a molecular and cellular framework underlying the innate immunity loss of tolerance to allogeneic tissues. Additionally, B. schlosseri was developed as a model for studying hematopoietic stem cell (HSC) transplantation, and it provides further insights into the similarities between the HSC niches of human and B. schlosseri. In this review, we discuss why studying the molecular and cellular pathways that direct successful innate immune tolerance in B. schlosseri can provide novel insights into and potential modulations of these immune processes in humans.

Prevention of Teratogenesis in Pregnancies of Obese Rats by Vitamin E Supplementation

Congenital malformations are a common adverse outcome in pregnancies complicated by pregestational obesity, although the underlying mechanisms are still unrevealed. Our aim was to study the effect of oxidative stress in obesity-induced teratogenesis. Wistar rats were fed a high-fat diet for 13 weeks, with (OE group) or without (O group) vitamin E supplementation. Then, rats were mated and sacrificed at day 11.5 of gestation. Embryos from O dams presented a 25.9 ± 3.5% rate of malformations (vs. 8.7 ± 3.4% in C rats), which was reduced in the OE group (11.5 ± 2.3%). Pregestational obesity induced hepatic protein and DNA oxidation and a decline in antioxidant enzymes. Importantly, glutathione content was also decreased, limiting the availability of this antioxidant in the embryos. Vitamin E supplementation efficiently maintained glutathione levels in the obese mothers, which could be used in their embryos to prevent oxidation-induced malformations. To test the effect of decreasing glutathione levels alone in a cell culture model of neuroepithelium, murine embryonic stem cells (ESC) were induced to form neuronal precursors and glutathione synthesis was inhibited with the gamma–glutamylcysteine synthesis inhibitor, buthionine sulfoximine (BSO). BSO inhibited the expression of Pax3, a gene required for neural tube closure that is also inhibited by oxidative stress. Taken together, our data indicate that obesity causes malformations through the depletion of maternal glutathione, thereby decreasing glutathione-dependent free radical scavenging in embryos, which can be prevented by vitamin E supplementation.

The role of decidual natural killer cell derived soluble factors in early pregnancy

Decidual natural killer cell (dNK), the predominant decidual lymphocytes in early pregnancy, are primarily identified based on their CD56^bright CD16^- phenotype and play an important role in maintaining immune tolerance at the maternal-fetal interface. dNK dysfunction reportedly leads to pathological pregnancy. Indeed, various dNK-derived soluble factors are involved in a series of key processes related to pregnancy outcomes. In this review, we summarize the roles of these dNK-derived factors in immune tolerance and embryonic development to improve the current understanding regarding the physiological and pathological mechanisms that occur during pregnancy, while potentially informing the development of effective therapeutics.

Functional NK surrogate biomarkers for inflammatory recurrent pregnancy loss and recurrent implantation failure

PROBLEM

Expansion of circulating NK cells has been related to pregnancy complications. This study aims at investigating several surface NK cell markers to identify a baseline inflammatory profile in women with recurrent pregnancy loss (iRPL) and recurrent implantation failure (iRIF).

METHOD OF STUDY

Expression of NKp30, TIGIT, NKp46, and DNAM-1 on total peripheral blood NK subsets, regulatory (CD56^bright CD16^neg ), and cytotoxic (CD56^dim CD16^pos/neg ) NK cells was measured.

RESULTS

Eighty-three women were recruited and classified into two groups, 58 women with RPL and 25 with RIF. A control group of 31 fertile women was included. Expression of NKp30 on cytNK was significantly higher in RPL (p = .019) and RIF (p < .001) than HC. TIGIT on cytNK cells was also higher in both RPL (p < .001) and RIF (p < .01). An optimal cutoff of 70% for NKp30⁺ cytNK disclosed a sensitivity of 82%, a specificity of 55%, and 83% PPV for RPL diagnosis. A cutoff level of 83% for TIGIT⁺ cytNK was chosen to discriminate between healthy controls and RPL women, with PPV of 84%.

CONCLUSION

Our preliminary data on this RPL and RIF cohorts suggest a simple diagnostic tool by combining NKp30 and TIGIT on cytNK cells to better identify a subgroup of RPL and RIF patients with a baseline inflammatory profile. A more rigorous selection of these patients through phenotyping peripheral cytNK cells may better define patients that could benefit from an immunomodulatory treatment to prevent further pregnancy losses. The performance of these biomarkers requires further investigation and validation in independent cohorts.

Toxoplasma Effectors that Affect Pregnancy Outcome

As an immune-privileged organ, the placenta can tolerate the introduction of antigens without inducing a strong inflammatory response that would lead to abortion. However, for the control of intracellular pathogens, a strong Th1 response characterized by the production of interferon-γ is needed. Thus, invasion of the placenta by intracellular parasites puts the maternal immune system in a quandary: The proinflammatory response needed to eliminate the pathogen can also lead to abortion. Toxoplasma is a highly successful parasite that causes lifelong chronic infections and is a major cause of abortions in humans and livestock. Here, we discuss how Toxoplasma strain type and parasite effectors influence host cell signaling pathways, and we speculate about how this might affect the outcome of gestation.

Gut and Reproductive Tract Microbiota Adaptation during Pregnancy: New Insights for Pregnancy-Related Complications and Therapy

Pregnancy is characterized by maternal adaptations that are necessary to create a welcoming and hospitable environment for the fetus. Studies have highlighted how the microbiota modulates several networks in humans through complex molecular interactions and how dysbiosis (defined as quantitative and qualitative alterations of the microbiota communities) is related to human pathologies including gynecological diseases. This review analyzed how maternal uterine, vaginal, and gut microbiomes could impact on fetus health during the gestational period. We evaluated the role of a dysbiotic microbiota in preterm birth, chorioamnionitis, gestational diabetes mellitus and pre-eclampsia. For many years it has been hypothesized that newborns were sterile organisms but in the past few years this paradigm has been questioned through the demonstration of the presence of microbes in the placenta and meconium. In the future, we should go deeper into the concept of in utero colonization to better understand the role of microbiota through the phases of pregnancy. Numerous studies in the literature have already showed interesting results regarding the role of microbiota in pregnancy. This evidence gives us the hope that microbiota modulation could be a novel strategy to reduce the morbidity and mortality related to pregnancy complications in the future.

The Role of the FOXO1/β2-AR/p-NF-κB p65 Pathway in the Development of Endometrial Stromal Cells in Pregnant Mice under Restraint Stress

Restraint stress causes various maternal diseases during pregnancy. β₂-Adrenergic receptor (β₂-AR) and Forkhead transcription factor class O 1 (FOXO1) are critical factors not only in stress, but also in reproduction. However, the role of FOXO1 in restraint stress, causing changes in the β₂-AR pathway in pregnant mice, has been unclear. The aim of this research was to investigate the β₂-AR pathway of restraint stress and its impact on the oxidative stress of the maternal uterus. In the study, maternal mice were treated with restraint stress by being restrained in a transparent and ventilated device before sacrifice on Pregnancy Day 5 (P5), Pregnancy Day 10 (P10), Pregnancy Day 15 (P15), and Pregnancy Day 20 (P20) as well as on Non-Pregnancy Day 5 (NP5). Restraint stress augmented blood corticosterone (CORT), norepinephrine (NE), and blood glucose levels, while oestradiol (E2) levels decreased. Moreover, restraint stress increased the mRNA levels of the FOXO family, β₂-AR, and even the protein levels of FOXO1 and β₂-AR in the uterus and ovaries. Furthermore, restraint stress increased uterine oxidative stress level. In vitro, the protein levels of FOXO1 were also obviously increased when β₂-AR was activated in endometrial stromal cells (ESCs). In addition, phosphorylated-nuclear factor kappa-B p65 (p-NF-κB p65) and its target genes decreased significantly when FOXO1 was inhibited. Overall, it can be said that the β₂-AR/FOXO1/p-NF-κB p65 pathway was activated when pregnant mice were under restraint stress. This study provides a scientific basis for the origin of psychological stress in pregnant women.

Prevalence of Thyroid Autoimmunity in Women with Recurrent Pregnancy Loss

Background and objectives: Thyroid autoimmunity (TAI) has been associated with a significantly increased risk of miscarriage in women with recurrent pregnancy loss (RPL). The aim of this study was to determine the prevalence of TAI in women with RPL and compare the clinical characteristics of positive and negative TAI women. Materials and Methods: This is a retrospective cross-sectional study; 203 women with RPL were included. Thyroid profile, anti-thyroid peroxidase (TPO-Ab), and anti-thyroglobulin (TG-Ab) antibodies were measured in all participants. Clinical characteristics and causes of RPL were compared between positive and negative TAI. Results: Prevalence of TAI was 14.8%; prevalence of positive TPO-Ab and TG-Ab was 12.3% and 4.9%, respectively. Women with TAI had significantly higher concentrations of thyrotropin (TSH) compared to women without TAI (4.8 ± 3.8 versus 3.1 ± 1.1, p = 0.001). There was no significant difference in age, the number of gestations, miscarriages, state of antiphospholipid antibodies (aPL), or causes of RPL between women that were TAI-positive versus TAI-negative. Prevalence of positive TAI by cause of RPL was: endocrine 7/25 (28%), genetic 1/5 (20%), autoimmune 1/5 (20%), anatomic 8/55 (14.5%), and unexplained cause 13/112 (11.6%). Conclusions: The prevalence of TAI in women with RPL is 14.8%. Women with an endocrine cause have the highest prevalence of TAI.

Using the Immune System to Manage Immunologically-Mediated Pregnancy Loss

Pregnancy is not nearly as successful as laypersons might assume, challenged as it is by several complications such as threatened abortion, spontaneous miscarriage, preeclampsia, and preterm delivery, among others. The maternal immune system has been shown to contribute to the etiopathogenesis of some of these pregnancy complications. Pro-inflammatory and anti-inflammatory cytokines have been studied for their effects on pregnancy because of their powerful and versatile effects on cells and tissues. This review addresses the relationship between pro-inflammatory cytokines and recurrent miscarriage, which is an important complication of pregnancy. References for this review were identified by using PRISMA-IPD (Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data) Guidelines by conducting searches for published articles from January 1, 1990 until March 1, 2020 in the following databases: PubMed, Google Scholar, and MEDLINE via OVID by the use of the search terms “recurrent spontaneous miscarriage,” “cytokines,” “progesterone,” “progestogen,” “dydrogesterone,” and “immunomodulation.” This review also presents the proposed mechanisms of action of pro-inflammatory cytokines in pregnancy loss, and then goes on to discuss the modulation of cytokine profiles to a state that is favorable to the success of pregnancy. In addition to its indispensable endocrinologic role of progesterone in pregnancy, it also has some intriguing immunomodulatory capabilities. We then summarize studies that show that progesterone and dydrogesterone, an orally-administered progestogen, suppress the production of pro-inflammatory cytokines and enhance the production of anti-inflammatory cytokines before mentioning clinical studies on progestogen supplementation. These studies support the contention that progestogens should be explored for the immunotherapeutic management of pregnancy complications.

Definition and Multiple Factors of Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is usually defined as three or more spontaneous abortions prior to 20-28 weeks gestation. RSA affects approximately 2-5% of all women of childbearing age, and it brings tremendous psychological and psychiatric trauma to the women and also results in economic burden. The causes could be female age, anatomical and chromosomal abnormalities, genetic, endocrinological, placental anomalies, infection, smoking and alcohol consumption, psychological factor, exposure to environmental factors such as heavy metal, environment pollution, and radiation.

Immunomodulatory properties of extracellular vesicles in the dialogue between placental and immune cells

Extracellular vesicle (EV)-mediated communication has been implicated in the cooperative alliance between trophoblast and immune cells toward maternal tolerance and placentation. Syncytiotrophoblast cells secrete EVs directly into the maternal circulation, which are taken up by immune cells, endothelial cells, and other cell types. Initial evidence also shows that EVs produced by immune cells are, in turn, incorporated by trophoblast cells and modulate placental responses. Non-coding RNAs (ncRNAs), proteins, and lipid mediators transported in EVs are able to influence proliferation, differentiation, cytokine production, and immunological responses of recipient cells. The molecular alphabet and cellular targets involved in this dialogue are being revealed. Nevertheless, several questions regarding the whole content, surface markers, and biological functions of EVs still remain to be investigated in both physiological and pathological conditions. Analysis of circulating EVs in maternal blood has the potential to serve as a minimally invasive approach to monitoring placental functions and immunological features of pregnancy, aiding in the diagnostics of complications. This review addresses the immunomodulatory properties of EVs and their tasks in the communication between placental and immune cells.

Immunology of the Placenta

In this article, the authors provide a general overview of the major immune cells present at the maternal-fetal interface, describe the key mechanisms used by the placenta to promote maternal immune regulation, tolerance, and adaptation, and discuss how dysregulation of these pathways could lead to obstetric complications such as pregnancy loss and preeclampsia. Finally, they conclude with a description of the innate immune properties of the human placenta that not only serve to protect the pregnancy from infection but also contribute to pregnancy complications such as preterm birth.

Expression of the Peptidase "Fibroblast Activation Protein" on Decidual Stromal Cells Facilitating Tissue Remodeling

INTRODUCTION

Expression of fibroblast activation protein (FAP) has been detected in activated fibroblasts participating in injury response, fibrotic and inflammatory conditions, and tumorigenesis. Human endometrium is equally characterized by rapid tissue remodeling events due to the reproductive tasks comprising the activity of proteolytic enzymes.

OBJECTIVE

We therefore hypothesized that FAP-positive fibroblasts could also be involved in physiological processes requiring tissue remodeling, such as decidualization during early pregnancy.

METHODS/RESULTS

The expression of FAP was analyzed by immunohistochemistry in frozen sections of decidual tissue from early pregnancy (gestational weeks: 6-12). All tissue samples clearly displayed a strong expression of FAP on the surface of stromal fibroblasts. Additionally, the percentage of FAP-positive fibroblasts freshly isolated from the decidua of the corresponding gestational weeks was calculated by applying FACS analysis. Decidual fibroblasts of different gestational weeks showed a significant decrease in FAP expression between the 6th and 7th weeks of gestation, which was followed by a steady slow reconstitution. By analyzing the expression of cytokines, chemokines, and growth factors of isolated FAP-positive decidual fibroblasts, we detected high levels of monocyte-attracting chemokines (growth-related oncogene alpha and monocyte chemoattractant protein-1 and -2), granulocyte-attracting chemokines (e.g., IL-8), proinflammatory factors (IL-1α and tumor necrosis factor alpha), and angiogenic substances (e.g., vascular endothelial growth factor and IL-8), which all promote an optimal microenvironment for implantation and growth of the conceptus.

CONCLUSIONS

Our data demonstrate that the healthy early pregnancy decidua is characterized by a general occurrence of FAP-positive fibroblasts possibly participating in active tissue remodeling during implantation.