Maternal-fetal immunity and recurrent spontaneous abortion.

Recurrent Spontaneous Abortion (RSA) is a common pregnancy complication, that has multifactorial causes, and currently, 40%-50% of cases remain unexplained, referred to as Unexplained RSA (URSA). Due to the elusive etiology and mechanisms, clinical management is exceedingly challenging. In recent years, with the progress in reproductive immunology, a growing body of evidence suggests a relationship between URSA and maternal-fetal immunology, offering hope for the development of tailored treatment strategies. This article provides an immunological perspective on the pathogenesis, diagnosis, and treatment of RSA. On one hand, it comprehensively reviews the immunological mechanisms underlying RSA, including abnormalities in maternal-fetal interface immune tolerance, maternal-fetal interface immune cell function, gut microbiota-mediated immune dysregulation, and vaginal microbiota-mediated immune anomalies. On the other hand, it presents the diagnosis and existing treatment modalities for RSA. This article offers a clear knowledge framework for understanding RSA from an immunological standpoint. In conclusion, while the "layers of the veil" regarding immunological factors in RSA are gradually being unveiled, our current research may only scratch the surface. In terms of immunological etiology, effective diagnostic tools for RSA are currently lacking, and the efficacy and safety of immunotherapies, primarily based on lymphocyte immunotherapy and intravenous immunoglobulin, remain contentious.

THBS1 regulates decidualization in URSA.

Inappropriate endometrial stromal decidualization has been implied as an important reason of many pregnancy-related complications, such as unexplained recurrent spontaneous abortion (URSA), preeclampsia and intrauterine growth restriction. Here, we observed that thrombospondin-1 (THBS1), an adhesive glycoprotein, was significantly downregulated in endometrial decidual cells from patients with URSA. The immortalized human endometrial stromal cell line T-HESC was used to investigate the possible THBS1-mediated regulation of decidualization. In vitro experiments found that the expression level of THBS1 increased with the normal decidualization process. Knockdown of THBS1 could decrease the expression levels of prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP1), two acknowledged human decidualization markers. Whereas, THBS1 overexpression could reverse these effects. The RNA sequencing results demonstrated that the extracellular regulated protein kinases (ERK) signaling pathway was potentially affected by the knockdown of THBS1. And we further confirmed that the regulation of THBS1 on decidualization was achieved through the ERK signaling pathway by the treatment of inhibitors. Moreover, knockdown of THBS1 in pregnant mice could impair decidualization and result in an increased fetus resorption rate. Altogether, our study demonstrated a crucial role of THBS1 in the pathophysiological process of URSA and provided some new insights into the research of pregnancy-related complications.

Association between urinary polycyclic aromatic hydrocarbons and unexplained recurrent spontaneous abortion from a case-control study.

Polycyclic aromatic hydrocarbons (PAHs) have been reported to be associated with adverse pregnancy outcomes. However, there is limited knowledge regarding the effects of single or mixed PAHs exposure on unexplained recurrent spontaneous abortion (URSA). This study aimed to investigate the association between monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and URSA in a case-control study. The results showed that 1-NAP, 2-NAP, 9-FLU, and 1-PYR were detected in 100% of the subjects among measured all sixteen OH-PAHs. Compared with those in the lowest quartiles, participants in the highest quartiles of 3-BAA were associated with a higher risk of URSA (OR (95%CI) = 3.56(1.28-9.85)). With each one-unit increase of ln-transformed 3-BAA, the odds of URSA increased by 41% (OR (95%CI) = 1.41(1.05-1.89)). Other OH-PAHs showed negative or non-significant associations with URSA. Weighted quantile sum (WQS) regression, Bayesian kernel machine regression (BKMR), and quantile-based g-computation (qgcomp) analyses consistently identified 3-BAA as the major contributor to the mixture effect of OH-PAHs on URSA. Our findings suggest that exposure to 3-BAA may be a potential risk factor for URSA. However, further prospective studies are needed to validate our findings in the future.

HOTAIR/miR-1277-5p/FBN2 signaling axis is involved in recurrent spontaneous abortion by regulating the growth, migration, and invasion of HTR-8/SVneo cells.

OBJECTIVE: This study aimed to explore the specific pathways by which HOX transcript antisense intergenic RNA (HOTAIR) contributes to the pathogenesis of unexplained recurrent spontaneous abortion (URSA). METHODS: Real-time quantitative PCR (RT-qPCR) was employed to assess the differential expression levels of HOTAIR in chorionic villi tissues from URSA patients and women with voluntarily terminated pregnancies. HTR-8/SVneo served as a cellular model. Knockdown and overexpression of HOTAIR in the cells were achieved through siRNA transfection and pcDNA3.1 transfection, respectively. Cell viability, migration, and invasion were evaluated using cell counting kit-8 (CCK-8), scratch, and Transwell assays, respectively. The interaction among the HOTAIR/miR-1277-5p/fibrillin 2 (FBN2) axis was predicted through bioinformatics analysis and confirmed through in vitro experiments. Furthermore, the regulatory effects of the HOTAIR/miR-1277-5p/FBN2 signaling axis on cellular behaviors were validated in HTR-8/SVneo cells. RESULTS: We found that HOTAIR was downregulated in chorionic villi tissues from URSA patients. Overexpression of HOTAIR significantly enhanced the viability, migration, and invasion of HTR-8/SVneo cells, while knockdown of HOTAIR had the opposite effects. We further confirmed the regulatory effect of the HOTAIR/miR-1277-5p/FBN2 signaling axis in URSA. Specifically, HOTAIR and FBN2 were found to reduce the risk of URSA by enhancing cell viability, migration, and invasion, whereas miR-1277-5p exerted the opposite effects. CONCLUSION: HOTAIR promotes URSA development by targeting inhibition of miR-1277-5p/FBN2 axis.

Baicalin ameliorates deficient decidualization in URSA by regulating mitochondrial fission induced necroptosis.

Unexplained recurrent spontaneous abortion (URSA) is a common complication of pregnancy that affects the health of pregnant women. Deficient endometrial decidualization has been associated with URSA. However, the underlying mechanism is poorly understood. This study aims to explore the mechanisms of mitochondrial fission induced necroptosis in deficient decidualization in URSA, and explore the regulation of baicalin on this mechanism. Initially, decidual tissues were collected from patients with URSA and health controls. Subsequently, in vitro induced decidualization model of Telomerase-Immortalized Human Endometrial Stromal Cells (T-hESCs) was constructed. Additionally, murine models of URSA (CBA/J × DBA/2) and normal pregnancy (CBA/J × BALB/c) were established, respectively. The level of decidualization, necroptosis, and mitochondrial fission of decidual tissues from clinical samples were detected. The function of mitochondrial fission on necroptosis during decidualization in T-hESCs was assessed by enhancing or inhibiting mitochondrial fission or necroptosis. Finally, CBA/J × DBA/2 pregnant mice were administrated with different doses of baicalin or saline, and the expression of mitochondrial fission, necroptosis, and decidualization markers were verified. The results of the study demonstrated a significant decrease in decidualization markers in the decidual tissues of URSA patients (P < 0.05), along with an increase in the incidence of cell necroptosis (P < 0.05) and hyperactive mitochondrial fission (P < 0.05). In vitro experiments, LPS was induced to trigger necroptosis of T-hESCs during induced decidualization, and decidualization markers IGFBP1 and PRL were subsequently decreased (P < 0.05). Besides, the mitochondrial fission agonist Tyrphostin A9 was found to promote the level of necroptosis (P < 0.05) and induced deficient decidualization (P < 0.05), which could be rescued by mitochondrial fission inhibitor Mdivi-1 and necroptosis inhibitor Nec-1 (P < 0.05). In addition, baicalin was shown to reduce hyperactive mitochondrial fission (P < 0.05), necroptosis (P < 0.05) and ameliorate deficient decidualization in vitro and in URSA murine models (P < 0.05). Collectively, baicalin shows potential in ameliorating deficient decidualization in URSA by inhibiting mitochondrial fission-triggered necroptosis.

The role of Th17 and Treg cells in normal pregnancy and unexplained recurrent spontaneous abortion (URSA): New insights into immune mechanisms.

Recurrent spontaneous abortion (RSA) has various causes, including chromosomal abnormalities, a prethrombotic state, and abnormal uterine anatomical factors. However, in about 50% of cases, the cause remains unknown and is referred to as unexplained recurrent spontaneous abortion (URSA). The fetus is protected from rejection by the maternal system, acting as an allogeneic gene, and immune tolerance serves as a crucial mechanism. The Th17/Treg cell paradigm's emergence as a new subpopulation of CD4+ T cells, interacting with one another, plays an essential role in the immune microenvironment and the body's defense system. This Th17/Treg cell model helps to explain the pathology of recurrent miscarriage that could not be accounted for by the original immune mechanism based on the Th1/Th2 model. Furthermore, the plasticity of Th17 and Treg cells holds innovative significance in autoimmunity and abortion. This paper reviews the role of Th17/Treg cellular immune response in the maintaining normal pregnancy and understanding unexplained recurrent spontaneous abortion.

Intercellular communication involving macrophages at the maternal-fetal interface may be a pivotal mechanism of URSA: a novel discovery from transcriptomic data.

Unexplained recurrent spontaneous abortion (URSA) is a severe challenge to reproductive females worldwide, and its etiology and pathogenesis have not yet been fully clarified. Abnormal intercellular communication between macrophages (Mφ) and decidual stromal cells (DSCs) or trophoblasts has been supposed to be the key to URSA. However, the exact molecular mechanisms in the crosstalk are not yet well understood. This study aimed to explore the potential molecule mechanism that may be involved in the communication between Mφ and DSC or trophoblast cells and determine their diagnostic characteristics by using the integrated research strategy of bioinformatics analysis, machine learning and experiments. First, microarrays of decidual tissue (GSE26787, GSE165004) and placenta tissue (GSE22490) in patients with URSA, as well as microarrays involving induced decidualization (GSE94644) and macrophage polarization in vitro (GSE30595) were derived from the gene expression omnibus (GEO) database. And 721 decidua-differentially expressed genes (DEGs), 613 placenta-DEGs, 510 Mφ polarization DEGs were obtained in URSA by differential expression analysis. Then, the protein-protein interaction (PPI) network was constructed, and the hub genes were identified by CytoHubba in Cytoscape software and validated by real-time PCR assay. Subsequently, immune enrichment analysis on decidua-DEGs and placenta-DEGs by ClueGO verified their regulation effects on Mφ. Besides, functional enrichment analysis was performed on Mφ polarization DEGs and the essential module genes derived from the weighted gene co-expression network analysis (WGCNA) to uncover the biological function that were related to abnormal polarization of Mφ. Furthermore, we screened out 29, 43 and 22 secreted protein-encoding genes from DSC-DEGs, placenta-DEGs and Mφ polarization DEGs, respectively. Besides, the hub secreted-protein-encoding genes were screened by CytoHubba. Moreover, we conducted functional enrichment analysis on these genes. And spearman correlation analysis between hub secreted-protein-encoding genes from donor cells and hub genes in recipient cells was performed to further understand the molecular mechanism of intercellular communication further. Moreover, signature genes with diagnostic value were screened from secreted protein-encoding genes by machine learning and validated by immunofluorescence co-localization analysis with clinical samples. Finally, three biomarkers of DSCs (FGF9, IL1R2, NID2) and three biomarkers of Mφ (CFB, NID2, CXCL11) were obtained. In conclusion, this project provides new ideas for understanding the mechanism regulatory network of intercellular communication involving macrophages at the maternal-fetal interface of URSA. Also, it provides innovative insights for the diagnosis and treatment of URSA.

Efficacy and safety of recombinant human granulocyte colony-stimulating factor in patients with unexplained recurrent spontaneous abortion: A systematic review and meta-analysis.

INTRODUCTION: Published data regarding efficacy of intrauterine perfusion of recombinant human granulocyte colony-stimulating factor for patients with unexplained recurrent spontaneous abortion (URSA) is inconclusive. This study aims at evaluating the efficacy and safety of G-CSF in URSA. MATERIALS AND METHODS: Electronic databases were searched including Cochrane Library, PubMed, Embase, China Biology Medicine disc, China Science and Technology Journal Database, Wanfang Database and China National Knowledge Infrastructure Database (last search was performed on Sep 10th, 2022). A systematic review and meta-analysis was conducted with R-language software. Combined relative risk (RRs), and 95% confidence intervals (CIs) were calculated to estimate efficacy and safety. RESULTS: Compared with placebo, the efficacy of G-CSF in the treatment of URSA patients was significant in conception rate (RR=1.34, 95%CI: 1.03-1.74, P = 0.028), and was none of significance in live birth rate (RR=1.35, 95%CI: 0.99-1.84, P = 0.06). Subgroup analysis showed that the ovulation-period-medication was the protective factor for conception rate, while "Ethnicity Asian" and "ovulation-period medication" were the protective factors for live birth rate. When it comes to the safety of rhG-CSF on URSA, meta-analysis showed that rhG-CSF had no significant effect on the incidence of adverse events (AEs) (RR=1.13, 95% CI: 0.89-1.43, P = 0.322), and subgroup analysis showed that the incidence of AEs in each subgroup did not increase significantly (P > 0.05). CONCLUSION: Based on our meta-analysis, intrauterine perfusion of rhG-CSF in ovulation period is an effective and safe way to improve conception rate in URSA.

Integrated analysis of lncRNA and mRNA expression profiles in patients with unexplained recurrent spontaneous abortion.

PROBLEM: Unexplained recurrent spontaneous abortion (URSA) is one of the most frustrating and confounding conditions in reproductive medicine, and its exact pathogenesis has not been clearly established. METHOD OF STUDY: In this study, we used RNA sequencing to characterize the mRNA and lncRNA expression profiles in peripheral blood. Thereafter, enrichment analysis was performed to determine the functions of the differentially expressed genes, and Cytoscape was used to construct lncRNA-mRNA interaction networks. RESULTS: Our results showed that the peripheral blood of patients with URSA has distinct mRNA and lncRNA expression profiles, with a total of 359 mRNAs and 683 lncRNAs being differentially expressed. Moreover, the top hub genes, including IGF1, PPARG, CCL3, RETN, SERPINE1, HESX1, and PRL, were identified and further validated using real-time quantitative PCR. Furthermore, we demonstrated a lncRNA-mRNA interaction network that achieved 12 key lncRNAs and their targeted mRNAs are involved in systemic lupus erythematosus, allograft rejection, and complement and coagulation cascades. Finally, the correlation between immune cell subtypes and IGF1 expression was evaluated; a negative correlation was observed with the proportion of natural killer cells, which increased significantly in URSA. CONCLUSION: We identified seven top hub genes, constructed a lncRNA-related network and suggested that IGF1 plays a key role in regulating maternal immune response by affecting NK and T cells' function, which helps to identify the pathogenesis of URSA.

Clinical Research into Treating Unexplained Recurrent Spontaneous Abortion during Early Pregnancy with the Qing Yi Tiao Mian Formula.

OBJECTIVE: The present study aims to analyze the clinical effect of the Qing Yi Tiao Mian (QYTM) formula on unexplained recurrent spontaneous abortion (URSA) during early pregnancy and the immune balance of T lymphocytes. METHODS: With their consent, 45 patients with URSA in weeks 4-9 of pregnancy were separated into three groups, i.e., the conventional fetal protection (n = 15), prednisone treatment (n = 10), and QYTM formula treatment (n = 20) groups. These patients received treatment once they had been diagnosed with an intrauterine pregnancy. The conventional fetal protection group was given progesterone (20 ∼ 40 mg daily injection) for four weeks. The prednisone treatment group was given progesterone (20 ∼ 40 mg daily injection) + prednisone (5 mg/d) for four weeks. The QYTM formula treatment group was given progesterone (20 ∼ 40 mg daily injection) + QYTM formula (one dose per day) for four weeks. In addition, women who had previously had a normal pregnancy were enrolled as a control group (n = 18). The success rate of the pregnancy in the first trimester was observed in each group, and the proportion of T lymphocytes in the peripheral blood before and after treatment was recorded. RESULTS: Among the 20 patients with URSA in the QYTM formula treatment group, 19 remained pregnant. Thus, the success rate during early pregnancy was 95%, which was significantly higher than the conventional fetal protection (53.33%) and prednisone treatment (70%) groups. The CD8+ T and natural killer (NK) cells population in the URSA groups was higher compared with the control group (P < 0.01). The QYTM formula treatment significantly decreased the ratio of CD8+ T lymphocytes (P < 0.01) and NK cells (P < 0.01). CONCLUSION: The QYTM formula significantly decreased the spontaneous abortion rate in patients with URSA during early pregnancy. The mechanism may be closely related to the inhibition of the killer lymphocytes' proliferation by CD8+ T lymphocytes and NK cells.

Associations between urinary monohydroxylated polycyclic aromatic hydrocarbons and unexplained recurrent spontaneous abortion and health risk assessment in a large case-control study in China.

Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental endocrine disruptors with known carcinogenic, reproductive, and developmental toxicity. Important knowledge gaps remain regarding the relationship between PAH exposure and unexplained recurrent spontaneous abortion (URSA). In the present study, twelve monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) were measured in the urine of 413 URSA cases and 434 controls. The main OH-PAHs measured in this study were monohydroxy metabolites of naphthalene, followed by fluorene and phenanthrene. After the creatinine correction, the median concentration of urinary OH-PAHs in the control group (17.4 µg/g Creatinine) was higher than that in the case group (14.2 µg/g Creatinine). There was no positive relationship between PAH exposure and URSA using binary logistic regression analysis. Among 847 Chinese women of childbearing age, residential environment, type of drinking water, and education level were the influencing factors of PAH exposure. The health risk assessment showed that over 98% of women had a carcinogenic risk with carcinogenic risk values above the acceptable level (10-6). Although this large-scale case-control study did not observe an association between PAH exposure and URSA, more attention should be paid to the high carcinogenic risk due to PAH exposure in women of reproductive age.

Low-dose aspirin protects unexplained recurrent spontaneous abortion via downregulation of HMGB1 inflammation activation.

Background: High mobility group box protein 1 (HMGB1) is considered as a kind of sterile inflammatory mediators, which is an overexpression in patients with unexplained recurrent spontaneous abortion (URSA). Specific targeting effect of aspirin on HMGB1 has been revealed. Our previous studies have explored the application of HMGB1 as a therapeutic target of aspirin in URSA disease of mice model and human, but the dynamic process of aspirin downregulating HMGB1 concentration has not been demonstrated. Methods: From December 2018 to November 2020, women with URSA (n = 91) and control women (n = 90) with no history of recurrent abortion or adverse pregnancy were included in the Reproductive Medicine Center of the First Affiliated Hospital of Anhui Medical University. ELISA was applied to detect the concentrations of HMGB1 and IFN-γ in the peripheral blood. Thirty-one URSA patients were monitored for low-dose aspirin treatment (2 and 4 weeks), the changes of HMGB1 and IFN-γ concentrations in peripheral blood of URSA patients before and after using aspirin were compared, and pregnancy outcomes after aspirin treatment were followed up. Results: The levels of HMGB1 in peripheral blood were significantly higher in URSA patients compared with controls, decreasing trends of HMGB1 and IFN-γ concentrations in plasma of URSA patients were observed after treatment with low-dose aspirin continuously, and the expression of HMGB1 was positively correlated with IFN-γ. There were no birth abnormalities in the babies of the URSA patients treated with aspirin. Conclusions: High levels of HMGB1 may be one of the pathogenesis of URSA. Low-dose aspirin may provide protective effect on the HMGB1-triggered URSA.

Frequency of HLA­G UTR­1/UTR­3/UTR­7 in women with unexplained recurrent spontaneous abortion.

Human leukocyte antigen (HLA)-G is an important molecule that maintains maternal-fetal interface tolerance and plays a vital role in a healthy pregnancy. Single-nucleotide polymorphisms in the 3'-untranslated regions (UTR) of the HLA-G gene may differ in women with unexplained recurrent spontaneous abortion (URSA). The present study involved the isolation of genome DNA from peripheral blood leukocytes, Sanger sequencing and analysis of the polymorphism sites in the 3'UTR of the HLA-G gene based on polymerase chain reaction. In total, 261 DNA samples from cases of URSA (n=133), including primary URSA (n=83) and secondary URSA (n=50), and controls (n=128) were evaluated. The present data showed that +3010CC genotype carriers exhibited a higher risk of URSA, while +3187GG genotype carriers exhibited a lower risk. Secondary URSA patients carrying +3010C had a higher risk of URSA, while +3187G carriers exhibited a lower risk of URSA. UTR-1 haplotype carriers may be associated with a reduced risk of primary and secondary URSA. Notably, UTR-3 and UTR-7 could increase the risk of primary and secondary URSA, respectively. The present results showed that HLA-G 3'UTR polymorphisms and haplotypes may be involved in URSA development and be a predictor of pregnancy outcome.

A missense variant in NCF1 is associated with susceptibility to unexplained recurrent spontaneous abortion.

Unexplained recurrent spontaneous abortion (URSA) is a major concern in reproductive medicine. Neutrophil cytosolic factor 1 (NCF1) polymorphisms leading to low production of reactive oxygen species (ROS) are strongly associated with autoimmune diseases. We investigated the association of the missense single nucleotide polymorphism (SNP) rs201802880 (NCF1-339) in NCF1 with URSA and explored its function. We performed NCF1-339 SNP genotyping of samples from 152 Chinese patients with URSA and 72 healthy controls using nested PCR and TaqMan assays. ROS production and RELA (NF-κB subunit) expression in the blood of participants with different NCF1-339 genotypes were determined. The frequencies of the wild-type (GG) and mutant (GA) genotypes remarkably differed between the URSA and control groups. The mutant genotype was associated with an increased risk of recurrent abortion. Furthermore, ROS levels in the URSA group with the GG genotype were significantly higher than those in the group with the GA genotype (p < 0.05). RELA expression in URSA patients with the GA genotype was considerably higher than that in control individuals with the GG genotype. These findings indicate that mutations in NCF1 may increase the risk of URSA via the NADP/ROS/NF-κB signaling pathway, which has implications for the diagnosis and treatment of URSA.

Temporal changes in cyclinD-CDK4/CDK6 and cyclinE-CDK2 pathways: implications for the mechanism of deficient decidualization in an immune-based mouse model of unexplained recurrent spontaneous abortion.

BACKGROUND: Deficient endometrial decidualization has been associated with URSA. However, the underlying mechanism is poorly understood. This study aimed to investigate the temporal cytokine changes and the involvement of CyclinD-CDK4/6 and CyclinE-CDK2 pathways in the regulation of the G1 phase of the cell cycle during decidualization in a murine model of URSA. METHODS: Serum and decidual tissues of mice were collected from GD4 to GD8. The embryo resorption and abortion rates were observed on GD8 and the decidual tissue status was assessed. In addition, PRL, Cyclin D, CDK6, CDK4, Cyclin E, CDK2 expression in mice were measured. RESULTS: URSA mice showed high embryo resorption rate and PRL, Cyclin D, Cyclin E CDK2, CDK4, CDK6 down-regulation during decidualization. The hyperactivated Cyclin D-CDK4/CDK6 and cyclin E/CDK2 pathways inhibit the decidualization process and leading to deficient decidualization. CONCLUSION: Insufficient decidualization is an important mechanism of URSA. which is related to the decrease of Cyclin D、Cyclin E、 CDK2、CDK4 and CDK6 in decidualization process of URSA.

Association of thyroid peroxidase antibodies with the rate of first-trimester miscarriage in euthyroid women with unexplained recurrent spontaneous abortion.

Background: Unexplained recurrent spontaneous abortion is a serious reproductive problem of unknown etiology. Thyroid peroxidase antibodies (TPO-Ab) may be associated with pregnancy outcomes in unexplained recurrent spontaneous abortion with normal thyroid function. Objective: This study aimed to investigate the relationship between TPO-Ab and the first trimester miscarriage rate/live birth rate in women of unexplained recurrent spontaneous abortion with normal thyroid function. Methods: We retrospectively analyzed the clinical data of 297 women who met our strict inclusion criteria, comparing the first trimester miscarriage rate/live birth rate between the TPO-Ab positive and TPO-Ab negative groups. For the same purpose, we also performed subgroup analysis. Results: Of the included women, 76 (25.6%) were TPO-Ab positive, and 221 (74.4%) were negative. First trimester miscarriage rate differed between the two groups (36.8% vs 24.0%, RR = 1.54, 95% CI: 1.05-2.24, P = 0.030). In the younger subgroup (<35 years) and the primary RSA subgroup, First trimester miscarriage rate was also higher in the TPO-Ab positive group (33.3% vs 19.0%, RR = 1.75, 95% CI: 1.07-2.87, P = 0.030; 36.5% vs 21.7%, RR = 1.69, 95% CI: 1.10-2.58, P = 0.020). While the live birth rate was lower in women with TPO-Ab positive, the difference did not reach statistical significance, even in the subgroup analysis. Conclusion: Our results suggest that TPO-Ab is associated with first trimester miscarriage rate in euthyroid women with unexplained recurrent spontaneous abortion.

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

BACKGROUND: Unexplained recurrent spontaneous abortion (URSA) is one of the most common diseases in pregnancy and is mainly caused by immune disorders. The foetus is similar to semiallogeneic maternal tissue, so the balance of immune tolerance must be dynamically maintained during pregnancy. Decidual natural killer (dNK) cells primarily mediate the immune tolerance microenvironment at the maternal-fetal interface. By using single-cell RNA sequencing (scRNA-seq) and high-throughput transcriptome sequencing analysis, we explored the characteristic distribution of dNK cells in URSA patients. METHODS: Control maternal-fetal interface tissue (from normal pregnant women, n = 3) and case maternal-fetal interface tissue (from patients with URSA, n = 3) samples were analysed by scRNA-seq and high-throughput transcriptome sequencing. RESULTS: By scRNA-seq, we demonstrated the maturation process of the transition of dNK cells from cytotoxic characteristics to immune tolerance in transcriptome analysis. Moreover, compared with normal pregnant women, serious disturbances in the polarization process of dNK cells were found in URSA. Simultaneously, the transcriptional level of the extracellular matrix (ECM) in URSA patients showed a significant decrease. The dNK cells interacted with extravillous trophoblasts to achieve immune-tolerant polarization. CONCLUSIONS: Insufficient expression of KIRs during dNK cell differentiation might be a key reason why polarized dNK cells still had high cytotoxic reactivity in URSA patients. Abnormal expression of ECM may affect the interaction of dNK cells with EVTs, making dNK cells immature. Both resulted in maternal immune intolerance to the foetus during pregnancy.

Association of emerging and legacy per- and polyfluoroalkyl substances with unexplained recurrent spontaneous abortion.

Emerging per- and polyfluoroalkyl substances (PFAS) alternatives are increasingly used in daily life. Although legacy PFAS have been associated with miscarriage in previous studies, it remains unknown whether exposure to emerging and legacy PFAS has any impact on the risk of unexplained recurrent spontaneous abortion (URSA). We conducted a case-control study with 464 URSA cases who had at least 2 unexplained miscarriages and 440 normal controls who had at least one normal livebirth. Concentrations of 21 PFAS in plasma, including three emerging PFAS alternatives, eight linear and branched PFAS isomers, four short-chain PFAS, and six legacy PFAS, were measured by ultra-performance liquid chromatography coupled with a tandem mass spectrometry (UPLC-MS/MS). Multiple logistic regression was applied to evaluate the relationship between PFAS and URSA risk. Perfluorooctanoic acid (PFOA, median: 6.18 ng/mL), perfluorooctane sulfonate (PFOS, median: 4.10 ng/mL), and 6:2 chlorinated perfluoroalkyl ether sulfonic acid (6:2 Cl-PFESA, median: 2.27 ng/mL) were the predominant PFAS in the controls. Exposure to 6:2 Cl-PFESA [adjusted odds ratio (aOR) = 1.18 (95% CI: 1.00, 1.39)] and hexafluoropropylene oxide dimer acid (HFPO-DA) [aOR = 1.35 (95% CI: 1.15, 1.59)] were significantly associated with increased risks of URSA. Women with older age (>30 years old) had a stronger association between PFAS and URSA. Our results suggest that emerging PFAS alternatives may be an important risk factor for URSA.

Diminished miR-374c-5p negatively regulates IL (interleukin)-6 in unexplained recurrent spontaneous abortion.

Unexplained recurrent spontaneous abortion (URSA) is commonly observed, and seriously affects women's reproductive health. Excessive interleukin-6 (IL-6) production has been shown to frequently occur and relate to URSA pathogenesis. In this study, the miRNA expression profile in peripheral blood mononuclear cells (PBMCs) from URSA patients and normal pregnant (NP) women was assessed by miRNA microarray and real-time quantitative reverse-transcription polymerase chain reaction (qPCR). MiRNA target prediction tools and luciferase reporter assay were used to detect direct binding between miRNAs and IL6. Functional study of administering anti-IL-6 neutralizing antibody and miR-374c-5p mimics to an URSA animal model was performed to evaluate embryo resorption rates. In the results, compared with NP women, the expression of IL-6 increased markedly in PBMCs and decidual tissues at both mRNA and protein levels, while miR-374c-5p expression decreased significantly. Prediction software and luciferase reporter assay showed that miR-374c-5p binds with IL6 3'UTR via the complementary bases. Transfection of miR-374c-5p mimics into an in vitro HeLa cell line significantly downregulated the expression of IL-6, while transfection of the miR-374c-5p inhibitor induced an opposite result. In the URSA mouse model, miR-374c-5p overexpression reduced the embryo resorption rate significantly, accompanied with decreased expression of IL-6 in the decidua. To sum up, downregulated miR-374c-5p was involved in the pathogenesis of URSA by enhancing IL-6 expression. Modulation of miR-374c-5p expression may be used to regulate IL-6 production for the treatment of URSA.

Astragalus polysaccharides combined with Codonopsis pilosula polysaccharides modulates the physiological characteristics of trophoblasts via miR-92a-1-5p/CCR7 axis.

BACKGROUND: When the abnormality occurs in proliferation, differentiation and apoptosis of trophoblasts, the invasion ability of placental trophoblast is weakened, which is prone to trigger the occurrence of various pregnancy diseases such as repeated spontaneous abortion (RSA). Clinically, Astragalus and Codonopsis pilosula polysaccharides (APS and CPPS) are used for the treatment of unexplained recurrent spontaneous abortion (URSA). Therefore, we aimed to probe into the roles of APS and CPPS in biological behaviors of placental trophoblasts. METHODS: The trophoblasts were treated with APS and CPPS, and transfected with miR-92a-1-5p mimic and CCR7 plasmid to explore the roles of APS and CPPS. Cell viability and apoptosis were determined by CCK-8 and flow cytometry, respectively. The levels of miRNA/mRNA and protein were measured by qRT-PCR and western blot, respectively. The interaction between miR-92a-1-5p and CCR7 was analyzed by TargetScan and dual-luciferase reporter assay. Invasion and migration rates were assessed by Transwell and wound healing assays, respectively. RESULTS: APS combined with CPPS enhanced viability, Bcl-2 expression, and migration and invasion capabilities, while suppressing apoptosis, and expressions of Bax, Bim and miR-92a-1-5p in trophoblasts. Nevertheless, miR-92a-1-5p mimic produced the inverse modulations in trophoblasts, and partially reversed the effects of APS and CPPS. Furthermore, overexpression of CCR7, the target of miR-92a-1-5p, partially offset the effect of miR-92a-1-5p mimic in trophoblasts. CONCLUSION: Astragalus combined with Codonopsis pilosula polysaccharides modulates the biological behaviors of trophoblasts via miR-92a-1-5p/CCR7 axis. The regulatory axis we studied will be helpful for the treatment of URSA in the future.