Endometrial Immune Dysfunction in Recurrent Pregnancy Loss

Upregulation of immune genes in the proliferative phase endometrium enables classification into women with recurrent pregnancy loss versus controls

STUDY QUESTION

Does the transcriptome of preconceptional endometrium in the proliferative phase show a specific profile in women with recurrent pregnancy loss (RPL)?

SUMMARY ANSWER

A specific differential gene expression signature in endometrial samples for women experiencing RPL compared with IVF control women was identified including an RPL subgroup characterized by upregulation of immune-related genes and pathways.

WHAT IS KNOWN ALREADY

RPL affects 1-3% of couples trying to become parents with both short- and long-term health implications; furthermore, the underlying pathophysiology is complex and heterogeneous with no explanations found for more than half of the couples. Some studies indicate that immunological dysfunction plays a role even preconceptionally and during implantation; however, the few published studies of endometrial transcriptomes from women with RPL have had small sample sizes and focused on the secretory phase of the menstrual cycle.

STUDY DESIGN, SIZE, DURATION

The study was based on two cohorts of women: an RPL cohort (n = 108) and a control cohort (n = 27). Endometrial samples were collected at two university hospital clinics from March 2013 until February 2019. Dating of the endometrium was made by histological examination by experienced pathologists.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All women were between 18 and 42 years at the time of collection of the biopsy. RPL was defined as three or more consecutive pregnancy losses or two second-trimester losses or stillbirths. The control group consisted of women referred to IVF/ICSI treatment with a presumed healthy endometrium. All biopsies, except one, were collected in a natural menstrual cycle. In total, 108 women with RPL were subjected to RNA-seq analysis. Seventy-six biopsies were in the proliferative phase, 29 were in the secretory phase, and three could not be classified. For the control women, in total, 27 were included in the RNA-seq analysis; 22 biopsies were in the proliferative phase, one was in the secretory phase, and four could not be classified. Total RNA was extracted from the endometrial biopsies, which had been stored in RNA stabilization solution at -80°C. RNA-seq reads were mapped and quantified using a reference transcriptome and analysed using principal component analysis (PCA), hierarchical clustering, and differential gene expression methods.

MAIN RESULTS AND THE ROLE OF CHANCE

PCA showed a clear separation of biopsies collected either in the proliferative or secretory phase. For the main analyses, we focused on the women with biopsies in the proliferative phase. PCA and differentially expressed genes (DEGs) revealed that RPL patients were characterized by upregulation of a limited number of immune-related genes and pathways. Further analyses revealed that subjects could describe a gene expression continuum, separable into four different subgroups by the gene expression data, where one subgroup consisted only of IVF controls, one was mixed, and two were composed of RPL patients only. The final analyses showed a distinct subgroup in the RPL cohort with stronger upregulation of immune-related genes, and deconvolution analyses of the bulk RNA-sequencing data together with immunohistochemistry analyses of the CD56 marker indicated an increased number of natural killer cells in this subgroup. A machine-learning model based on the Random Forest algorithm and gene expression data from the 157 DEGs (RPL vs controls) was trained on a subset of the cohort and validated using the remaining subjects, reaching on average 96.6% accuracy (95% CI: 93.3-96.7%), 95.7% sensitivity (95% CI: 95.7-95.7%), and 99.5% specificity (95% CI: 85.7-100.0%). The same analysis using only the most informative genes increased validation accuracies further.

LIMITATIONS, REASONS FOR CAUTION

The size of the IVF control group and difficulties in defining the most optimal type of control group is a recurrent limitation in this and other RPL studies. Some of the women from the control group might be subfertile in relation to endometrial factors. However, the current control group is a mix of women with different pregnancy and fertility records, which is a strength. Alternative control groups could be women with one to two healthy pregnancies or one to two pregnancy terminations. Furthermore, in only about 10% of the RPL cases information on foetal pathology or chromosomal aneuploidy was obtained.

WIDER IMPLICATIONS OF THE FINDINGS

The findings presented here indicate that a gene expression signature exists, which can be used to classify RPL patients versus control (non-RPL) women. An interesting aspect is that a pregnancy loss in some women thereby might result in a specific signature detectable as a specific endometrial gene expression profile possibly irrespectively of the cause of the pregnancy loss. Aside from contributing to a further understanding of the pathophysiology and development of new treatments, this finding could lead to a specific and cost-effective test that at an early stage could identify women with high risk of experiencing RPL. To this end, further perspectives include a prospective study, which would explore further utility of the predictive model by analysing endometrial samples collected in the proliferative phase from a cohort of women, who have experienced one pregnancy loss.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Region Zealand Health Sciences Research Foundation, Zealand University Hospital through the ReproHealth Research Consortium ZUH, the Frimodt-Heineke Foundation, 'Direktør Emil C. Hertz og Hustru Inger Hertz' Fond', the Torben and Alice Frimodt's Foundation, the Novo Nordisk Foundation, and the Independent Research Fund Denmark. L.H.J.A., R.S.M., Y.D., K.J.H., H.S.N., A.S., and T.V.F.H. are inventors on a patent application (number EP24171923.6) submitted by Region Zealand, The Capital Region of Denmark, and the University of Copenhagen that covers a diagnostic test based on the results of the study. The authors declared no other competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Silencing circRNA-ZFAND6 induces trophoblast apoptosis by activating the mitochondrial pathway through the miR-575/SOD2 axis in unexplained recurrent spontaneous abortion

BACKGROUND

Unexplained recurrent spontaneous abortion (URSA) is a major problem in the field of human reproductive health. At present, several circRNAs have been reported to be differentially expressed and play an important biological function in pregnancy-related diseases. However, the role of circRNAs in URSA remains unclear.

METHODS

Levels of circRNA and miRNA were examined by RT-qPCR. The si-RNA and overexpression plasmid were respectively used to silence and overexpress circRNA-ZFAND6. We investigated the biological function of circRNA-ZFAND6 on trophoblasts through CCK8, EdU, Flow cytometric assay, Wound-healing assays and Transwell. Dual luciferase activity assay was conducted to identify the interaction between miR-575 and circRNA-ZFAND6.

RESULTS

We confirmed that circRNA-ZFAND6 was a stable circular RNA and was mostly localized in the cytoplasm. CircRNA-ZFAND6 was downregulated in placental villous tissues of URSA. CCK-8 and EdU assays showed that circRNA-ZFAND6 promoted the proliferation of HTR-8/SVneo cells. Flow cytometry and western blot assays prompted that circRNA-ZFAND6 obviously reduced cells apoptosis. Scratch wound healing and transwell assays revealed that circRNA-ZFAND6 had no effect on cell migration and invasion. CircRNA-ZFAND6 worked by adsorbing miR-575 through the ceRNA mechanism. MiR-575 can inhibit the proliferation and promote the apoptosis of HTR8/SVneo cells. SOD2 was identified as a direct target of miR-575 and was associated with mitochondrial apoptosis. Transmission electron microscopy, TMRM and ROS staining assays both suggested that circRNA-ZFAND6 affected mitochondrial apoptosis. Excessive trophoblast apoptosis was a key event to promote the development of URSA.

CONCLUSION

CircRNA-ZFAND6, which is low expressed in URSA and regulates the apoptosis of trophoblast cells, may affect the expression of SOD2 and thus affect mitochondrial apoptosis by regulating miR-575. This is closely related to the occurrence of URSA.

The alteration of uterine microbiota participated in the activation of the decidual inflammatory response in early spontaneous abortion

BACKGROUND

Early spontaneous abortion (ESA) is one of the most common clinically recognized pregnancy complications. While multiple factors such as embryo abnormalities and maternal conditions may contribute to ESA, early identification and screening of maternal risk factors are increasingly important to explore the potential etiologies and improve prevention and treatment strategies for ESA. This study investigates the changes in uterine microbiota and the decidual immune response in ESA patients without embryo abnormalities.

METHODS

ESA patients without embryo abnormality and artificial abortion (AA) controls were enrolled for clinical characteristics analysis. The decidual endometrium was subsequently collected for histological evaluation and inflammatory indicator detection. Moreover, 16S rRNA gene sequencing of uterine secretions was performed to investigate the differences in uterine microorganisms between the ESA and AA groups.

RESULTS

Clinical analysis showed higher inflammatory response with elevated neutrophil counts in ESA patients. The increase in leukocytes, including neutrophils, was positively correlated with ESA. ESA patients presented significantly increased IL-1β expression in decidual stromal cells. 16S rRNA gene sequencing revealed greater diversity in the uterine microbiota of the ESA group, which presented decreased Lactobacillus abundance and increased abundance of other bacteria at the genus and species levels.

CONCLUSIONS

Changes in the uterine microbiome are likely related to inflammatory response and lead to early pregnancy loss.

An aerobe exercise intervention for optimizing metabolic, cardiovascular and immune status: protocol of an intervention study with a multi-systemic approach for women with unexplained recurrent pregnancy loss

Women confronted with recurrent pregnancy loss (RPL) are often desperately searching for a possible explanation and hoping they will someday fulfill a healthy pregnancy. Unfortunately, in more than 50% of these women no cause for their losses can be identified after clinical investigations and therefore clinicians have no treatment options to help these women. Although adaptations in several systems such as the metabolic, the cardiovascular, and the immune system are highly important to support early pregnancy, especially the contribution of a specific subset of immune cells in the uterus known as CD56bright Natural Killer (NK) cells has gained a lot of interest, investigating separate RPL associated factors might not be the way forward. Moreover, a readily available and non-invasive exercise intervention might optimize all systems simultaneously, reducing metabolic, cardiovascular and immunological risk factors contributing to RPL. Therefore, we propose an aerobe exercise intervention and study the influence on the cardiovascular, the metabolic, and the immune system, with a particular focus on endometrial CD56bright NK cells, in women with unexplained RPL. In this exercise intervention study, women with unexplained RPL will receive two questionnaires to assess baseline characteristics. Moreover, they will receive (1) an immunological assessment (by sampling menstrual blood, peripheral blood and a vaginal swab) (2) an assessment of the cardiovascular system (by transvaginal ultrasound to assess uterine artery perfusion, by measuring hemodynamic and autonomic nerve system responses during a tilt test and by maximum stress test on a cycle ergometer) and (3) a metabolic assessment (by sampling peripheral blood, urine and by measuring body characteristics) before and after intervention. The intervention consists of 12-weeks moderate exercise training based on 50-65% of heart rate reserve. One year after the end of the intervention women will receive a final questionnaire regarding possible subsequent pregnancy outcome. This clinical trial with a multi-systemic approach can not only provide new insights by studying contribution and associations of the immune system, the cardiovascular system and the metabolic system in women with unexplained RPL, it also can support shared decision-making between clinicians and patients by evaluating the importance of a ready available exercise intervention strategy.

Immune Treatment Strategies in Unexplained Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) is characterized by the occurrence of two or more consecutive pregnancy losses. Approximately half of these cases lack a clear etiology and are termed unexplained recurrent pregnancy loss (URPL). Maternal-fetal immune dysfunction is thought to be involved in causing URPL. Increased human leukocyte antigen compatibility, susceptibility genes, lack of blocking antibodies, and dysfunction of immune cells can all disrupt the immune tolerance environment of the maternal-fetal interface. To correct the maternal-fetal immune imbalances, some immunotherapies were recently tried to be used for patients with URPL. This review summarizes the characteristics and mechanisms of the immune microenvironment at the maternal-fetal interface of URPL patients, and the present immunotherapies for URPL patients, to serve as a reference for future research.

Pregnancy and perinatal outcomes in women with recurrent pregnancy loss-A case-control study

INTRODUCTION

Recurrent pregnancy loss (RPL), defined as two or more pregnancy losses, might be associated with elevated obstetrical and perinatal risks in the following pregnancies. RPL and pregnancy problems related to placental development may have similar etiological features. This study explores the incidences of pregnancy and perinatal outcomes in women with RPL.

MATERIAL AND METHODS

This retrospective case-control study investigated the outcomes of the next subsequent singleton pregnancy after thorough RPL examination (n = 360) in Helsinki University Hospital, Finland, in 2007-2016. Data for cases and four control women for each case, matched for age, parity, delivery month, year, and hospital (n = 1440), were retrieved from the Medical Birth Register. Primary outcomes were pregnancy and delivery complications, perinatal outcomes, and characteristics of pregnancy follow-up. Secondary outcomes were maternal and neonatal diagnoses. Associations between RPL and outcomes were estimated with risk ratios with 95% confidence intervals (CI). In sub-analyses, we compared the outcomes of secondary RPL with multipara controls and women with unexplained or explained RPL.

RESULTS

Women with RPL had a higher risk for gestational hypertension (3.1% vs. 1.4%, risk ratio [RR] 2.20 [Confidence interval (CI) 1.06-4.55], p = 0.03), preterm birth (8.9% vs. 5.8%, RR 1.54 [CI 1.04-2.28], p = 0.04), malpresentation of the fetus (3.3% vs. 1.5%, RR 2.18 [CI 1.09-4.37], p = 0.02), premature rupture of membranes (5.6% vs. 2.4%, RR 2.35 [CI 1.37-4.04], p = 0.002), and had more prenatal visits than controls. Mode of delivery was comparable between the study groups, although RPL women had more induced labor (28.1% vs. 22.2%, RR 1.26 [CI 1.04-1.53], p = 0.02). Mean birthweight was lower (3387 ± 680 g) in RPL women's newborns than in the control group (3482 ± 564 g, p = 0.02), and the risk of umbilical artery pH <7.10 (6.7% vs. 3.6%, RR 1.85 [CI 1.15-2.95], p = 0.03) was higher. Risk ratio for small for gestational age was higher in the secondary RPL group than in multipara controls (5.1% vs. 2.0%, RR 2.50 [CI 1.15-5.42], p = 0.02).

CONCLUSIONS

Women with a history of RPL seem to have higher risks in their subsequent pregnancies and should therefore be monitored carefully. These findings support the theory of placental development being the common nominator behind hypertensive pregnancy disorders and RPL.

The correlation between ANAs and pregnancy loss and their impact on IVF/ICSI-ET pregnancy outcomes in patients with recurrent pregnancy loss

OBJECTIVE

To explore the correlation between antinuclear antibodies (ANAs) and pregnancy loss (PL), and to observe its impact on the pregnancy outcomes of in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) in recurrent PL (RPL) patients.

METHODS

In this retrospective study, patients first seen at the hospital between January 2016 and December 2022 and who underwent two ANA tests within 4-6 weeks were included. After exclusion of confounding factors, patients were allocated to the non-pregnancy loss (non-PL), single-PL, or RPL group according to previous number of PLs, and the correlation between PL and ANAs was analyzed. The first embryo transfer (ET) after in vitro IVF/ICSI without immunological treatment was placed in the RPL group, and patients were classified into the ANA-negative or ANA-positive subgroup according to ANA titer. The effect of ANAs on pregnancy outcomes in the RPL patients after IVF/ICSI-ET was further analyze.

RESULTS

The results of multivariate unordered logistic regression showed that when the non-PL group was used as the reference, ANA positivity was an independent risk factor for RPL (P = 0.023) but not for single PL (P = 0.654). When the single-PL group was used as the reference, ANA positivity was an independent risk factor for RPL (P = 0.022). Multivariate logistic regression analysis revealed that the early PL rate of the ANA-positive subgroup was significantly higher than that of the ANA-negative subgroup (P = 0.009), and the total PL rate of the ANA-positive subgroup was significantly higher than that of the ANA-negative subgroup (P = 0.049).

CONCLUSION

The results showed that ANA positivity may be related to RPL occurrence, but there was no significant correlation between ANA positivity and single PL. ANA positivity is associated with PL occurrence in RPL patients after transfer, and the correlation is reflected mainly in the first trimester.

Immune dysregulation of decidual NK cells mediated by GRIM19 downregulation contributes to the occurrence of recurrent pregnancy loss

In patients with recurrent pregnancy loss (RPL), excessive activation of decidual natural killer (dNK) cells has been widely observed, yet the precise underlying mechanisms remain to be elucidated. We collected decidual specimens from RPL patients and controls to assess GRIM19 expression, activation phenotype, cytotoxic function, inflammatory cytokine secretion, and mitochondrial homeostasis in dNK cells. Furthermore, we established a GRIM19-knockout NK-92MI cell line and a GRIM19 ± C57BL/6J mouse model to investigate the relationship between GRIM19 downregulation and dNK immune dysregulation, ultimately contributing to pregnancy loss. Decidual NK cells from RPL patients exhibited significantly lower GRIM19 expression, accompanied by abnormal hyperactivation, enhanced cytotoxicity, and abnormal mitochondrial activation. In vitro experiments confirmed that reduced GRIM19 expression significantly potentiated the cytotoxicity and pro-inflammatory cytokine secretion of NK-92MI cells, while also promoting mitochondrial homeostasis imbalance. Mouse model studies corroborated that GRIM19 downregulation triggers NK cell homeostasis imbalance, contributing to the occurrence of pregnancy loss. Downregulation of GRIM19 in dNK cells contributes to RPL through hyperactivation and disruption of mitochondrial homeostasis, emphasizing its potential as a diagnostic and therapeutic target.

Understanding the heterogeneity of natural killer cells at the maternal-fetal interface: implications for pregnancy health and disease

Natural killer (NK) cells are the most abundant leukocytes located at the maternal-fetal interface; they respond to pregnancy-related hormones and play a pivotal role in maintaining the homeostatic micro-environment during pregnancy. However, due to the high heterogeneity of NK cell subsets, their categorization has been controversial. Here, we review previous studies on uterine NK cell subsets, including the classic categorization based on surface markers, functional molecules, and developmental stages, as well as single-cell RNA sequencing-based clustering approaches. In addition, we summarize the potential pathways by which endometrial NK cells differentiate into decidual NK (dNK) cells, as well as the differentiation pathways of various dNK subsets. Finally, we compared the alterations in the NK cell subsets in various pregnancy-associated diseases, emphasizing the possible contribution of specific subsets to the development of the disease.

How does chronic endometritis influence pregnancy outcomes in endometriosis associated infertility? A retrospective cohort study

BACKGROUND

Endometriosis (EMS) and chronic endometritis (CE) frequently coexist. This study aimed to examine the impact of CE on reproductive outcomes in patients with EMS.

METHODS

We enrolled 685 patients with endometriosis-associated infertility from January 2018 to December 2020. The patients were divided into CE (318) and non-CE (367) groups. A subset of 123 clinically pregnant women from the CE group and 369 from the non-CE group was selected for detailed comparison. Pregnancy and delivery data were meticulously collected from hospital records and through telephone interviews.

RESULTS

CE was diagnosed in 46.42% of EMS patients. Higher pregnancy rates were observed in patients with Endometriosis Fertility Index (EFI) scores of 7-10. EMS patients with CE had increased risks of placenta previa (13.01%), gestational hypertension (5.69%), and cesarean sections (59.34%).

CONCLUSIONS

CE, which is prevalent among EMS patients, is linked to increased risks of pregnancy complications, including placenta previa, gestational hypertension, and cesarean delivery. Although combined hysteroscopy and laparoscopy improve pregnancy rates, they demand careful management of these complications.

lncRNA-mediated immune system dysregulation in RIF; a comprehensive insight into immunological modifications and signaling pathways' dysregulation

The initial stage of biological pregnancy is referred to as implantation, during which the interaction between the endometrium and the fetus is crucial for successful implantation. Around 10% of couples undergoing in vitro fertilization and embryo transfer encounter recurrent implantation failure (RIF), a clinical condition characterized by the absence of implantation after multiple embryo transfers. It is believed that implantation failure may be caused by inadequate or excessive endometrial inflammatory responses during the implantation window, as the female immune system plays a complex role in regulating endometrial receptivity and embryo implantation. Recent approaches to enhance the likelihood of pregnancy in RIF patients have focused on modifying the mother's immune response during implantation by regulating inflammation. Long non-coding RNAs (lncRNAs) play a significant role in gene transcription during the inflammatory response. Current research suggests that dysfunctional lncRNAs are linked to various human disorders, such as cancer, diabetes, allergies, asthma, and inflammatory bowel disease. These non-coding RNAs are crucial for immune functions as they control protein interactions or the ability of RNA and DNA to form complexes, which are involved in differentiation, cell migration, and the production of inflammatory mediators. Given the apparent involvement of the immune system in RIF and the modulatory effect of lncRNAs on the immune system, this review aims to delve into the role of lncRNAs in immune system modulation and their potential contribution to RIF.

Doppler Evaluation of Uterine Blood Flow in Patients with Unexplained Recurrent Pregnancy Loss

Objective

This study aimed to analyze uterine artery and spiral artery hemodynamics in patients with unexplained recurrent pregnancy loss (URPL) with varying pregnancy outcomes.

Methods

174 pregnant women with URPL and 144 pregnant women without adverse pregnancy histories were enrolled in this retrospective study. Based on pregnancy outcomes, these patients were divided into two groups: normal pregnancy outcomes (URPL-N, n=138) and adverse pregnancy outcomes (URPL-A, n=36). Control group participants were categorized into normal pregnancy outcomes (CON-N, n=129) and adverse pregnancy outcomes (CON-A, n=15). We compared uterine artery and spiral artery hemodynamics during different stages of gestation and the predictive value of these parameters for pregnancy outcomes.

Results

URPL-N group had fewer pregnancy losses and lower BMI compared to URPL-A group (P< 0.05). Spiral artery hemodynamics in URPL-N and CON-N groups were lower than those in URPL-A and CON-A groups during the mid-luteal phase, 11-13 weeks, 15-17 weeks, and 19-21 weeks of gestation, respectively. Uterine artery hemodynamics ((Pulsatility index (mPI), resistive index (mRI), and systolic-to-diastolic ratio (mS/D)) in the mid-luteal period were lower in URPL-N group than URPL-A group. Similarly, in CON-N group were lower than CON-A group. The URPL-A and CON-A groups had higher uterine artery and spiral artery hemodynamics when compared to the URPL-N and CON-N groups. Spiral artery hemodynamics exhibited larger areas under the ROC curve compared to uterine artery parameters.

Conclusion

Abnormal hemodynamics in these arteries may contribute to URPL and adverse pregnancy outcomes. Spiral artery hemodynamics are more reliable predictors of pregnancy outcomes than uterine artery parameters.

Impact of Vitamin D deficiency on immunological and metabolic responses in women with recurrent pregnancy loss: focus on VDBP/HLA-G1/CTLA-4/ENTPD1/adenosine-fetal-maternal conflict crosstalk

BACKGROUND AND AIM

Recurrent pregnancy loss (RPL), also known as recurrent implantation failure (RIF), is a distressing condition affecting women characterized by two or more consecutive miscarriages or the inability to carry a pregnancy beyond 20 weeks. Immunological factors and genetic variations, particularly in Vit D Binding Protein (VDBP), have gained attention as potential contributors to RPL. This study aimed to provide insight into the immunological, genetic, and metabolic networks underlying RPL, placing a particular emphasis on the interactions between VDBP, HLA-G1, CTLA-4, ENTPD1, and adenosine-fetal-maternal conflict crosstalk.

METHODS

A retrospective study included 198 women with three or more consecutive spontaneous abortions. Exclusion criteria comprised uterine abnormalities, endocrine disorders, parental chromosomal abnormalities, infectious factors, autoimmune diseases, or connective tissue diseases. Immunological interplay was investigated in 162 female participants, divided into two groups based on their Vit D levels: normal Vit D-RPL and low Vit D-RPL. Various laboratory techniques were employed, including LC/MS/MS for Vit D measurement, ELISA for protein detection, flow cytometry for immune function analysis, and molecular docking for protein-ligand interaction assessment.

RESULTS

General characteristics between groups were significant regarding Vit D and glucose levels. Low Vit D levels were associated with decreased NK cell activity and downregulation of HLA-G1 and HLA-G5 proteins, while CTLA-4 revealed upregulation. VDBP was significantly downregulated in the low Vit D group. Our findings highlight the intricate relationship between Vit D status and adenosine metabolism by the downregulation of SGLT1, and NT5E, key components of adenosine metabolism, suggests that Vit D deficiency may disrupt the regulation of adenosine levels, leading to an impaired reproductive outcome. HNF1β, a negative regulator of VDBP, was upregulated, while HNF1α, a positive regulator, was downregulated in low Vit D women after RPL. Molecular docking analysis revealed crucial residues involved in the interaction between Vit D and HNF1β.

CONCLUSION

Collectively, these findings underscore the importance of Vit D in modulating immune function and molecular pathways relevant to pregnancy maintenance, highlighting the need for further research to elucidate the mechanisms and potential therapeutic interventions for improving pregnancy outcomes in individuals with Vit D deficiency and RPL.

Exploring the role of endoplasmic reticulum stress in recurrent spontaneous abortion: Identification of diagnostic biomarkers and immune cell interactions

Dysregulated endoplasmic reticulum stress (ERS) is associated with recurrent spontaneous abortion (RSA) and is involved in the mechanisms that govern immune balance and vascular regulation at the maternal-fetal interface. The molecular intricacies of these mechanisms remain elusive. This study employed microarray and bioinformatics techniques to examine genetic abnormalities in endometrial tissues from RSA patients, with the objective of identifying potential ERS-related biomarkers. By integrating two publicly available microarray datasets, consisting of 88 RSA and 42 control samples, we conducted an extensive analysis, including differential expression, functional annotation, molecular interactions, and immune cell infiltration. Analysis of immune cell characteristics suggests an inflammatory immune imbalance as a potential contributor to RSA progression. Both innate and adaptive immunity were found to play roles in RSA development, with M1 macrophages constituting a significant proportion of immune infiltration. We identified five key ERS-associated genes (TMEM33, QRICH1, MBTPS2, ERN1, and BAK1) linked to immune-related mechanisms, with RT-qPCR results aligning with bioinformatics findings. Our research findings offer a fresh and comprehensive perspective on the ERS-related genes' pathways and interaction networks, offering significant insights for the advancement of innovative therapy techniques for RSA.

Unexplained Recurrent Pregnancy Loss: Clinical Application of Immunophenotyping

PROBLEM

Recurrent pregnancy loss (RPL) is defined as the failure of two or more pregnancies and affects approximately 5% of couples, often without a clear cause. The etiologies of RPL include factors such as maternal age, endocrine dysfunction, uterine abnormalities, chromosomal abnormalities, thrombophilias, infections, and autoimmune disorders. However, these conditions account for only 50%-60% of RPL cases. Research has explored whether an altered immune system, compared to the physiological state, may be linked to RPL. This review aims to determine whether specific immunophenotypes are associated with unexplained Recurrent Pregnancy Loss (uRPL) and whether targeted therapies addressing specific immunophenotypic alterations can improve pregnancy outcomes.

METHODS

A literature review was conducted using Pubmed/Medline, Scopus, and Embase databases, analyzing data from 95 articles published between 2001 and 2023. The roles of various cells of the immune system (B lymphocytes, T lymphocytes, natural killer cells, macrophages) in different tissues (peripheral blood, menstrual blood) were specifically investigated in women with uRPL.

DISCUSSION AND CONCLUSION

Specific immunophenotypes have been demonstrated to be associated with this condition. However, there is a need to standardize immunophenotyping assays and conduct more trials to stratify RPL risk and improve potential therapeutic strategies.

Whole exome sequencing identifies a novel mutation in Annexin A4 that is associated with recurrent spontaneous abortion

Background

Recurrent spontaneous abortion (RSA) is a multifactorial disease, the exact causes of which are still unknown. Environmental, maternal, and genetic factors have been shown to contribute to this condition. The aim of this study was to investigate the presence of mutations in the ANXA4 gene in patients with RSA.

Methods

Genomic DNA was extracted from 325 patients with RSA and 941 control women with a normal reproductive history for whole-exome sequencing (WES). The detected variants were annotated and filtered, and the pathogenicity of the variants was predicted through the SIFT online tool, functional enrichment analyses, Sanger sequencing validation, prediction of changes in protein structure, and evolutionary conservation analysis. Furthermore, plasmid construction, Western blotting, RT-qPCR, and cell migration, invasion and adhesion assays were used to detect the effects of ANXA4 mutations on protein function.

Results

An ANXA4 mutation (p.G8D) in 1 of the 325 samples from patients with RSA (RSA-219) was identified through WES. This mutation was not detected in 941 controls or included in public databases. Evolutionary conservation analysis revealed that the amino acid residue affected by the mutation (p.G8D) was highly conserved among 13 vertebrate species, and the SIFT program and structural modeling analysis predicted that this mutation was harmful. Furthermore, functional assays revealed that this mutation could inhibit cell migration, invasion and adhesion.

Conclusion

Our study suggests that an unreported novel ANXA4 mutation (p.G8D) plays an important role in the pathogenesis of RSA and may contribute to the genetic diagnosis of RSA.

In-utero transfer of decidualized endometrial stromal cells increases the frequency of regulatory T cells and normalizes the abortion rate in the CBA/J × DBA/2 abortion model

Introduction

Failure to adequate decidualization leads to adverse pregnancy outcomes including pregnancy loss. Although there are plenty of reports underscoring immune dysfunction as the main cause of abortion in CBA/J females mated with DBA/2 males (CBA/J × DBA/2), little is known about the potential role of impaired endometrial decidualization.

Methods

Endometrial stromal cells (ESCs) from CBA/J mice were in-vitro decidualized, and the proteome profile of the secretome was investigated by membrane-based array. CBA/J mice were perfused In-utero with either decidualized ESCs (C×D/D), undecidualized ESCs (C×D/ND), or PBS (C×D/P) 12 days before mating with DBA/2 males. Control mice were not manipulated and were mated with male DBA/2 (C×D) or Balb/c (C×B) mice. On day 13.5 of pregnancy, reproductive parameters were measured. In-vivo tracking of EdU-labeled ESCs was performed using fluorescence microscopy. The frequency of regulatory T cells (Tregs) in paraaortic/renal and inguinal lymph nodes was measured by flow cytometry. The proliferation of pregnant CBA/J splenocytes in response to stimulation with DBA/2 splenocytes was assessed by 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) flow cytometry.

Results

In C×D/D mice, the resorption rate was reduced to match that seen in the C×B group. Intrauterine perfused ESCs appeared in uterine stroma after 2 days, which remained there for at least 12 days. There was no difference in the number of implantation sites and embryo weight across all groups. The frequency of Tregs in the inguinal lymph nodes was similar across all groups, but it increased in the paraaortic/renal lymph nodes of C×D/D mice to the level found in C×B mice. No significant changes were observed in the proliferation of splenocytes from pregnant C×D/D compared to those of the C×D group in response to stimulation with DBA/2 splenocytes. Decidualization of ESCs was associated with a profound alteration in ESC secretome exemplified by alteration in proteins involved in extracellular matrix (ECM) remodeling, response to inflammation, senescence, and immune cell trafficking.

Discussion

Our results showed that the deficiency of Tregs is not the primary driver of abortion in the CBA/J × DBA/2 model and provided evidence that impaired endometrial decidualization probably triggers endometrial immune dysfunction and abortion in this model.

Biochemical markers for prediction of the first half pregnancy losses: a review

Objective

26% of all pregnancies end in miscarriage, and up to 10% of clinically diagnosed pregnancies, and recurrent pregnancy loss is 5% among couples of childbearing ages. Although there are several known causes of pregnancy loss in the first half, including recurrent pregnancy loss, including parental chromosomal abnormalities, uterine malformations, endocrinological disorders, and immunological abnormalities, about half of the cases of pregnancy loss in its first half remain unexplained.

Methods

The review includes observational controlled studies (case-control or cohort, longitudinal studies, reviews, meta-analyses), which include the study of biochemical factors for predicting pregnancy losses in the first half, in singlet pregnancy. The Newcastle-Ottawa Scale (NOS) was used to assess the research quality.

Results

Finally, 27 studies were included in the review, which has 134904 examined patients. The results of the review include estimates of β-human chorionic gonadotropin, progesterone, pregnancy-associated protein - A, angiogenic vascular factors, estradiol, α-fetoprotein, homocysteine and CA-125 as a predictors or markers of the first half pregnancy losses.

Conclusion

It may be concluded that to date, research data indicate the unavailability of any reliable biochemical marker for predicting pregnancy losses in its first half and require either a combination of them or comparison with clinical evidence. A fairly new model shall be considered for the assessment of α-fetoprotein in vaginal blood, which may have great prospects in predicting spontaneous miscarriages.

Immunological Indicators of Recurrent Pregnancy Loss: A Mendelian Randomization Study

Recurrent pregnancy loss (RPL) is thought to be related to maternal-fetal immune tolerance disorders. Immune monitoring of RPL patients mainly involves two aspects: inflammatory factors and immune cells. However, most observational studies have reported controversial findings. This study aimed to confirm whether abnormal inflammatory factors and immune cells in peripheral blood may lead to RPL, and guide clinical immune monitoring. We demonstrated causality using two-sample Mendelian randomization. Sensitivity analysis, reverse Mendelian randomization and meta-analysis were used to enhance the effectiveness of the results. There was a causal relationship between the level of IL-12 (OR = 1.78, 95% CI = 1.25-2.55; P = 0.00149) and RPL for 41 inflammatory factors. We screened 5 groups of immune cell subtypes that were causally associated with RPL: switched memory B-cell absolute count (OR = 0.66, 95% CI = 0.49-0.87, P = 0.00406), IgD + CD24 + B-cell absolute count (OR = 0.69, 95% CI = 0.53-0.88, P = 0.00319), CD39 + resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.86, 95% CI = 0.78-0.95, P = 0.00252), activated & resting CD4 regulatory T-cell %CD4 regulatory T-cell (OR = 0.89, 95% CI = 0.82-0.97, P = 0.00938) and CD45 RA + CD28-CD8 + T-cell %CD8 + T-cell (OR = 0.99, 95% CI = 0.98-1.00, P = 0.01231). In terms of inflammatory factors, a causal relationship between IL-12 and RPL in peripheral blood was confirmed. We also identified five immune cell phenotypes that play a protective role. This suggests that there may be protective B cells and CD8 + T-cell subsets in peripheral blood, and the protective effect of Tregs was proved again. Immune monitoring of peripheral blood in patients with RPL seems to be necessary and the foundation for precision medicine.

Recombinant humanized type I collagen remodels decidual immune microenvironment at maternal-fetal interface by modulating Th17/Treg imbalance

Disruption of the extracellular matrix and dysregulation of the balance between Th17 and regulatory T cells are recognized as risk factors for recurrent spontaneous abortion (RSA). However, the interaction between matrix components and the Th17/Treg axis remains poorly elucidated. The result of this study revealed that the absence of type I collagen in the decidua is linked to Th17/Treg imbalance in RSA. Furthermore, we discovered that biomaterial recombinant humanized type I collagen (rhCOLI) promoted T cell differentiation into Tregs by inhibition the Notch1/Hes1 signaling pathway and enhanced the immunosuppressive function of Tregs, as indicated by increased secretion level of IL-10 and TGF-β. Importantly, this study is the first to demonstrate that rhCOLI can modulate the Th17/Treg imbalance, reduce embryo resorption rates, reshape the immune microenvironment at the maternal-fetal interface, and improve fertility in an RSA mouse model. Collectively, these findings suggest that type I collagen deficiency may contribute to, rather than result from, RSA, and propose a potential intervention for RSA using rhCOLI.

Rhoptry proteins affect the placental barrier in the context of Toxoplasma gondii infection: Signaling pathways and functions

Toxoplasma gondii is an opportunistic and pathogenic obligate intracellular parasitic protozoan that is widespread worldwide and can infect most warm-blooded animals, seriously endangering human health and affecting livestock production. Toxoplasmosis caused by T. gondii infection has different clinical manifestations, which are mainly determined by the virulence of T. gondii and host differences. Among the manifestations of this condition, abortion, stillbirth, and fetal malformation can occur if a woman is infected with T. gondii in early pregnancy. Here, we discuss how the T. gondii rhoptry protein affects host pregnancy outcomes and speculate on the related signaling pathways involved. The effects of rhoptry proteins of T. gondii on the placental barrier are complex. Rhoptry proteins not only regulate interferon-regulated genes (IRGs) to ensure the survival of parasites in activated cells but also promote the spread of worms in tissues and the invasive ability of the parasites. The functions of these rhoptry proteins and the associated signaling pathways highlight relevant mechanisms by which Toxoplasma crosses the placental barrier and influences fetal development and will guide future studies to uncover the complexity of the host-pathogen interactions.

Beyond the cradle - Amidst microplastics and the ongoing peril during pregnancy and neonatal stages: A holistic review

Advancements in research concerning the occurrence of microplastics (MPs) in human blood, sputum, urine, and breast milk samples have piqued the interest of the scientific community, prompting further investigation. MPs present in the placenta, amniotic fluid, and meconium raise concerns about interference with embryonic development, leading to preeclampsia, stillbirth, preterm birth, and spontaneous abortion. The challenges posed by MPs extend beyond pregnancy, affecting the digestive, reproductive, circulatory, immune, and central nervous systems. This has spurred scientists to examine the origins of MPs in distinct environmental layers, including air, water, and soil. These risks continue after birth, as neonates are continuously exposed to MPs through everyday items such as breast milk, cow milk and infant milk powder, as well as plastic-based products like feeding bottles and breast milk storage bags. It is the need of the hour to strike a balance amidst lifestyle changes, alternative choices to traditional plastic products, raising awareness about plastic-related health risks, and fostering collaboration between the scientific community and policymakers. This review aims to provide fresh insights into potential sources of MP pollution, with a specific focus on pregnancy and neonates. It is the first compilation of its kind so far that includes critical studies on recently reported discoveries.

Bibliometric analysis of the global trends in immune-related recurrent pregnancy loss research over the last two decades

PROBLEM

A comprehensive analysis was conducted to explore the scientific output on immune-related recurrent pregnancy loss (RPL) and its key aspects. Despite the lack of clear explanations for most RPL cases, immune factors were found to play a significant role.

METHOD OF STUDY

The study utilized a bibliometric approach, searching the Web of Science Core Collection database for relevant literature published between 2004 and 2023.

RESULTS

The collected dataset consisted of 2228 articles and reviews, revealing a consistent increase in publications and citations over the past two decades. The analysis identified the United States and China as the most productive countries in terms of RPL research. Among the institutions, Fudan University in China emerged as the top contributor, followed by Shanghai Jiaotong University. Kwak-kim J was the most prolific author, while Christiansen Ob had the highest number of co-citations. The top 25 co-cited references on diagnosis, treatment, and mechanisms formed the foundation of knowledge in this field. By examining keyword co-occurrence and co-citations, the study found that antiphospholipid syndrome and natural killer cells were the primary areas of focus in immune-related RPL research. Additionally, three emerging hotspots were identified: chronic endometritis, inflammation, and decidual macrophages. These aspects demonstrated increasing interest and research activity within the field of immune-related RPL.

CONCLUSIONS

Overall, this comprehensive bibliometric analysis provided valuable insights into the patterns, frontiers, and focal points of global scientific output related to immune-related RPL.

Evaluation of Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) affects approximately 5% of couples. Although RPL definitions vary across professional societies, an evaluation after a second clinically recognized first-trimester pregnancy loss is recommended. Good quality evidence links parental chromosomal rearrangements, uterine anomalies, and antiphospholipid syndrome (APS) to RPL. In contrast, the relationship between RPL and other endocrine, hematologic, and immunologic disorders or environmental exposures is less clear. Anticoagulant therapy and low-dose aspirin are recommended for patients with RPL who have also been diagnosed with APS. Vaginal progesterone supplementation may be considered in patients experiencing vaginal bleeding during the first trimester. Surgical correction may be considered for patients with RPL in whom a uterine anomaly is identified. Evaluation and management of additional comorbidities should be guided by the patient's history rather than solely based on the diagnosis of RPL, with the goal of improving overall health to reduce complications in the event of pregnancy. Most people with RPL, including those without identifiable risk factors, are expected to achieve a live birth within 5 years from the initial evaluation. Nevertheless, clinicians should be sensitive to the psychological needs of individuals with this condition and provide compassionate and supportive care across all stages.

Identification of hub genes in placental dysfunction and recurrent pregnancy loss through transcriptome data mining: A meta-analysis

Recurrent pregnancy loss (RPL) is a condition characterized by the loss of two or more pregnancies before 20 weeks of gestation. The causes of RPL are complex and can be due to a variety of factors, including genetic, immunological, hormonal, and environmental factors. This transcriptome data mining study was done to explore the differentially expressed genes (DEGs) and related pathways responsible for pathogenesis of RPL using an Insilco approach. RNAseq datasets from the Gene Expression Omnibus (GEO) database was used to extract RNAseq datasets of RPL. Meta-analysis was done by ExpressAnalyst. The functional and pathway enrichment analysis of DEGs were performed using KEGG and BINGO plugin of Cytoscape software. Protein-protein interaction was done using STRING and hub genes were identified. A total of 91 DEGs were identified, out of which 10 were downregulated and 81 were upregulated. Pathway analysis indicated that majority of DEGs were enriched in immunological pathways (IL-17 signalling pathway, TLR-signalling pathway, autoimmune thyroid disease), angiogenic VEGF-signalling pathway and cell-cycle signalling pathways. Of these, 10 hub genes with high connectivity were selected (CXCL8, CCND1, FOS, PTGS2, CTLA4, THBS1, MMP2, KDR, and CD80). Most of these genes are involved in maintenance of immune response at maternal-fetal interface. Further, in functional enrichment analyses revealed the highest node size in regulation of biological processes followed by cellular processes, their regulation and regulation of multicellular organismal process. This in-silico transcriptomics meta-analysis findings could potentially contribute in identifying novel biomarkers and therapeutic targets for RPL, which could lead to the development of new diagnostic and therapeutic strategies for this condition.

BMP4 in Human Endometrial Stromal Cells Can Affect Decidualization by Regulating FOXO1 Expression

CONTEXT

Recurrent spontaneous abortion (RSA) is defined as the loss of 2 or more consecutive intrauterine pregnancies with the same sexual partner in the first trimester. Despite its significance, the etiology and underlying mechanisms of RSA remain elusive. Defective decidualization is proposed as one of the potential causes of RSA, with abnormal decidualization leading to disturbances in trophoblast invasion function.

OBJECTIVE

To assess the role of bone morphogenetic protein 4 (BMP4) in decidualization and RSA.

METHODS

Decidual samples were collected from both RSA patients and healthy controls to assess BMP4 expression. In vitro cell experiments utilized the hESC cell line to investigate the impact of BMP4 on decidualization and associated aging, as well as its role in the maternal-fetal interface communication. Subsequently, a spontaneous abortion mouse model was established to evaluate embryo resorption rates and BMP4 expression levels.

RESULTS

Our study identified a significant downregulation of BMP4 expression in the decidua of RSA patients compared to the normal control group. In vitro, BMP4 knockdown resulted in inadequate decidualization and inhibited associated aging processes. Mechanistically, BMP4 was implicated in the regulation of FOXO1 expression, thereby influencing decidualization and aging. Furthermore, loss of BMP4 hindered trophoblast migration and invasion via FOXO1 modulation. Additionally, BMP4 downregulation was observed in RSA mice.

CONCLUSION

Our findings highlighted the downregulation of BMP4 in both RSA patients and mice. BMP4 in human endometrial stromal cells was shown to modulate decidualization by regulating FOXO1 expression. Loss of BMP4 may contribute to the pathogenesis of RSA, suggesting potential avenues for abortion prevention strategies.

Bulk RNA-sequencing, single-cell RNA-sequencing analysis, and experimental validation reveal iron metabolism-related genes CISD2 and CYP17A1 are potential diagnostic markers for recurrent pregnancy loss

BACKGROUND

Recurrent pregnancy loss (RPL) is associated with variable causes. Its etiology remains unexplained in about half of the cases, with no effective treatment available. Individuals with RPL have an irregular iron metabolism. In the present study, we identified key genes impacting iron metabolism that could be used for diagnosing and treating RPL.

METHODS

We obtained gene expression profiles from the Gene Expression Omnibus (GEO) database. The Molecular Signatures Database was used to identify 14 gene sets related to iron metabolism, comprising 520 iron metabolism genes. Differential analysis and a weighted gene co-expression network analysis (WGCNA) of gene expression revealed two iron metabolism-related hub genes. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry were used on clinical samples to confirm our results. The receiver operating characteristic (ROC) analysis and immune infiltration analysis were conducted. In addition, we analyzed the distribution of genes and performed CellChat analysis by single-cell RNA sequencing.

RESULTS

The expression of two hub genes, namely, CDGSH iron sulfur domain 2 (CISD2)and Cytochrome P450 family 17 subfamily A member 1 (CYP17A1), were reduced in RPL, as verified by both qPCR and immunohistochemistry. The Gene Ontology (GO) analysis revealed the genes predominantly engaged in autophagy and iron metabolism. The area under the curve (AUC) demonstrated better diagnostic performance for RPL using CISD2 and CYP17A1. The single-cell transcriptomic analysis of RPL demonstrated that CISD2 is expressed in the majority of cell subpopulations, whereas CYP17A1 is not. The cell cycle analysis revealed highly active natural killer (NK) cells that displayed the highest communications with other cells, including the strongest interaction with macrophages through the migratory inhibitory factor (MIF) pathway.

CONCLUSIONS

Our study suggested that CISD2 and CYP17A1 genes are involved in abnormal iron metabolism, thereby contributing to RPL. These genes could be used as potential diagnostic and therapeutic markers for RPL.

Comparison of serum levels of interleukin 33 in combination with serum levels of C-reactive protein, Immunoglobulin G, Immunoglobulin A, and Immunoglobulin M in recurrent pregnancy loss: A case-control study

Background

One of the critical cases of recurrent pregnancy loss is immunological factors, whereas obtaining effective prevention or treatment is necessary for cognition of reasons.

Objective

In this study, we tried to evaluate some immunological factors related to recurrent pregnancy loss.

Materials and Methods

This case-control study was conducted on 66 women at the age of 18-35 yr who were referred to the Clinic of Gynecology and Obstetrics, Ali Ibn Abi Taleb hospital, Zahedan, Iran, from August-December 2019. Interleukin 33 (IL-33) serum levels were measured using enzyme-linked immunosorbent assay. Immunoglobulin G, Immunoglobulin A, Immunoglobulin M (IgM), and C-reactive protein levels were measured by serology and hematology methods.

Results

The mean age of total participants was 30.8 ± 3.80 yr. The mean serum IL-33 in the case group was 318.5 ± 254.1 pg/ml and was lower than the control group (354.2 ± 259.9 pg/ml), which was not statistically significant (p = 0.52). The level of C-reactive protein in the case and control was not significantly different (p = 0.27), and Immunoglobulin A and Immunoglobulin G in the case and control were also not significantly different (p = 0.46, and p = 0.16, respectively), but there were significant differences (p = 0.003) between the level of the IgM in the case and control groups.

Conclusion

No statistically significant difference was observed in the IL-33 serum level, for at least 4-6 months after the last abortion in the case group and the final live birth in the control group. In contrast, serum levels of IgM were statistically significant. Finally, the need for more studies is felt according to the different results of the previous studies in this field.

Meta-analysis of FOXP3 polymorphisms and recurrent spontaneous abortion susceptibility

BACKGROUND

The polymorphisms of the FOXP3 gene may mediate abnormalities in Tregs, leading to an imbalance in maternal-fetal immune tolerance and ultimately resulting in recurrent spontaneous abortion (RSA). This meta-analysis aims to assess the potential association between FOXP3 polymorphisms and susceptibility to RSA using five specific single nucleotide polymorphisms (SNPs).

MATERIALS AND METHODS

By conducting a comprehensive search across databases such as EMBASE, PubMed, Web of Science, Cochrane Library, CNKI, Wanfang, and CBM, we identified suitable studies for inclusion in the meta-analysis. The data extracted from these studies were subjected to analysis using Stata SE 15. To assess the degree of association, we utilized the odds ratio (OR) along with its corresponding 95% confidence intervals (CI). Five specific single nucleotide polymorphisms (SNPs) were employed in assessing the connection between FOXP3 gene polymorphisms and RSA.

RESULTS

The meta-analysis demonstrated a significant association between several polymorphisms (rs3761548, rs2232365, rs2232368, rs2280883, and rs2294021) and susceptibility to RSA. Conversely, the FOXP3 rs5902434 polymorphism was not associated with susceptibility to RSA.

CONCLUSION

Our meta-analysis suggests that these genetic variations within the FOXP3 gene might play a role in the progression of RSA disease. Meanwhile, large-scale studies that consider multiple factors are needed to validate this finding.

An immune window of opportunity to prevent spontaneous abortion: prepregnancy peripheral leukocytes and subsets were associated with a decreased risk of spontaneous abortion

STUDY QUESTION

Do prepregnancy peripheral leukocytes (PPLs) and their subsets influence the risk of spontaneous abortion (SAB)?

SUMMARY ANSWER

PPLs and their subsets are associated with the risk of SAB.

WHAT IS KNOWN ALREADY

Compelling studies have revealed the crucial role of maternal peripheral leukocytes in embryo implantation and pregnancy maintenance. Adaptive changes are made by PPLs and their subsets after conception.

STUDY DESIGN, SIZE, DURATION

This population-based retrospective cohort study was based on data from the National Free Pre-pregnancy Check-up Project (NFPCP) in mainland China. Couples preparing for pregnancy within the next six months were provided with free prepregnancy health examinations and counseling services for reproductive health. The current study was based on 1 310 494 female NFPCP participants aged 20-49 who became pregnant in 2016. After sequentially excluding 235 456 participants lost to follow-up, with multiple births, and who failed to complete blood tests, a total of 1 075 038 participants were included in the primary analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

PPLs and their subset counts and ratios were measured. The main outcome was SAB. A multivariable logistic regression model was used to estimate the odds ratio (OR) and 95% CI of SAB associated with PPLs and their subsets, and restricted cubic spline (RCS) was used to estimate the nonlinear exposure-response relationship.

MAIN RESULTS AND ROLE OF CHANCE

Of the included pregnant participants, a total of 35 529 SAB events (3.30%) were recorded. Compared to participants with reference values of PPLs, the ORs (95% CIs) of leukopenia and leukocytosis for SAB were 1.14 (1.09-1.20) and 0.74 (0.69-0.79), respectively. The RCS result revealed a monotonous decreasing trend (Pnonlinear < 0.05). Similar relationships were observed for the neutrophil count and ratio, monocyte count, and middle-sized cell count and ratio. The lymphocyte ratio showed a positive and nonlinear relationship with the risk of SAB (Pnonlinear < 0.05). Both eosinophils and basophils showed positive relationships with the risk of SAB (eosinophil Pnonlinear > 0.05 and basophil Pnonlinear < 0.05).

LIMITATIONS, REASONS FOR CAUTION

Chemical abortion events and the cause of SAB were not collected at follow-up. Whether women with abnormal PPLs had recovered during periconception was not determined.

WIDER IMPLICATIONS OF THE FINDINGS

PPLs and their subsets are associated with the risk of SAB. Leukopenia and neutropenia screening in women preparing for pregnancy and developing a feasible PPL stimulation approach should be emphasized to utilize the immune window of opportunity to prevent SAB.

STUDY FUNDING/COMPETING INTEREST(S)

This study was approved by the Institutional Research Review Board of the National Health and Family Planning Commission. This study was supported by the National Key Research and Development Program of China (grants 2021YFC2700705 [Y.Y.] and 2016YFC100307 [X.M.]) and the National Natural Science Foundation of China (grant no. 82003472 [L.W.]). The funding source was not involved in the study design, data collection, analysis and interpretation of the data, writing the report, or the decision to submit this article for publication. No competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Low follistatin level is a causal risk factor for spontaneous abortion: a two-sample mendelian randomization study

Background

Recurrent pregnancy loss is a distressing event during pregnancy, and understanding its causal factors is crucial. Follistatin, a glycoprotein involved in folliculogenesis and embryogenesis, has been implicated as a potential contributor to the risk of spontaneous abortion. However, establishing a causal relationship requires rigorous investigation using robust methods.

Methods

In this study, we utilized mendelian randomization (MR), a powerful genetic epidemiological approach, to examine the causal relationship between follistatin levels and spontaneous abortion. We obtained instrumental variables strongly associated with follistatin levels from large-scale genome-wide association from the IEU database. The inverse variance weighting (IVW) method was taken as gold standard. We also performed sensitivity test to evaluate the robustness of our result.

Results

MR analysis revealed a significant causal relationship between low follistatin levels and spontaneous abortion (p = 0.03). Sensitivity analyses, including pleiotropy test, heterogeneity test, and leave-one-out analysis, all supported the robustness of our findings.

Conclusion

Our study provides compelling evidence supporting the causal relationship between low follistatin levels and increased risk of spontaneous abortion. These findings underscore the importance of follistatin in the etiology of spontaneous abortion and suggest potential preventive interventions. Modulating follistatin levels or relevant pathways could hold promise for reducing the incidence of spontaneous abortion and improving reproductive outcomes. The utilization of MRs strengthens the validity of our results by mitigating confounding and reverse causality biases. Further research is needed to elucidate the underlying molecular mechanisms and explore therapeutic strategies targeting follistatin levels.

Associations of Nutrients and Dietary Preferences with Recurrent Pregnancy Loss and Infertility

This review examines associations of nutrients and dietary preferences with recurrent pregnancy loss (RPL), miscarriage, and infertility. Research articles, reviews, and meta-analyses of RPL and infertility that focused on nutrition, meals, and lifestyle were reviewed, and associations of nutrients and dietary preferences with pregnancy are discussed in relation to recent research findings. Studies related to RPL were given the highest priority, followed by those dealing with miscarriage and infertility. Multivitamin supplements-even when lacking folic acid or vitamin A-reduced total fetal loss. High-dose folic acid supplementation before conception reduced the risk of miscarriage and stillbirth. A meta-analysis revealed a strong association of vitamin D deficiency/insufficiency with miscarriage. Another meta-analysis revealed that seafood and dairy products reduced the risk of miscarriage, whereas a caffeine intake of 300 mg/day or more was associated with miscarriage. A balanced diet that included nutrients with antioxidant properties helped prevent miscarriage, whereas a diet that included processed foods and nutrients with proinflammatory effects increased the risk of miscarriage. Associations of nutrients with RPL warrant further research.

MANF Promotes Unexplained Recurrent Miscarriages by Interacting with NPM1 and Downregulating Trophoblast Cell Migration and Invasion

Dysplasia and invasive defects in early trophoblasts contribute to unexplained recurrent miscarriages (URMs). Mesencephalic astrocyte-derived neurotrophic factor (MANF) inhibits migration and invasion in some cancer cells, but its role in pregnancy-related diseases remains unresolved. Here, we found that MANF levels in the peripheral blood and aborted tissue of URM women were higher than in normal controls, irrespective of pregnancy or miscarriage. We confirm the interaction between MANF and nucleophosmin 1 (NPM1) in trophoblasts of URM patients, which increases the ubiquitination degradation of NPM1, leading to upregulation of the p53 signaling pathway and inhibition of cell proliferation, migration, and invasion ability. Using a URM mouse model, we found that MANF downregulation resulted in reduced fetal resorption; however, concomitant NPM1 downregulation led to increased abortion rates. These data indicate that MANF triggers miscarriage via NPM1 downregulation and p53 activation. Thus, MANF downregulation or disruption of the MANF-NPM1 interaction could be targets for URM therapeutics.

Oral administration of Bifidobacterium longum ES1 reduces endometrial inflammation in women with recurrent pregnancy loss

BACKGROUND

Over-activation of endometrial inflammasome NALP-3 (Nod-like receptor family pyrin domain containing 3) can be found in recurrent pregnancy loss (RPL) women probably due to leaky gut and passage into circulation of lipopolysaccharides (LPS). Leaky gut can be caused by exposure to gluten in RPL women genetically predisposed to celiac disease, positive for Human Leukocyte Antigen (HLA)-DQ2/DQ8 haplotype. Oral administration of Bifidobacterium longum ES1 (GliadinES®) can inactivate gluten peptides toxicity to epithelial gut cells and improve gut barrier.

METHODS

We investigated by enzyme-linked immunoassay: (a) serum levels of LPS and zonuline (a marker of leaky gut); (b) LPS, NALP-3, caspase-1, interleukine (IL)-1β and IL-18 concentration in endometrial fluids, in untreated women with uncomplicated pregnancies (negative HLA-DQ2/DQ8 haplotype) (n = 22) and in women with unexplained RPL, HLA-DQ2/DQ8 positive (n = 22), before and after daily oral administration for 3 months of GliadinES®.

RESULTS

RLP women showed higher serum levels of LPS (p < 0.0001) and higher concentration of LPS (p < 0.0001), NALP-3 (p < 0.01); Caspase-1 (p < 0.0001), IL-1β (p < 0.0001), and IL-18 (p < 0.0001) in endometrial fluids compared to controls. GliadinES® treatment significantly reduced serum levels of both LPS (p < 0.0001) and zonuline (p < 0.01), as well as LPS (p < 0.5), NALP-3 (p < 0.01), Caspase-1 (p < 0.001), IL-1β (p < 0.001), and IL-18 (p < 0.01) concentrations in endometrial fluids of RPL women.

CONCLUSIONS

RPL women positive for HLA-DQ2/DQ8 haplotype show increased circulating and endometrial levels of LPS and endometrial inflammasome NALP-3 over-activation. Oral administration of GliadinES® can reduce gut permeability, decrease serum levels of LPS and, contextually, improve endometrial inflammation in this specific subset of RPL women.

Vitamin D levels in non-pregnant women with a history of recurrent pregnancy loss with and without autoantibodies

Background

The objective of this study was to compare the levels of vitamin D in non-pregnant women with a history of recurrent pregnancy loss (RPL) who were seropositive or seronegative for autoantibodies (autoAbs).

Methods

The study examined 58 RPL patients with autoAbs (ANA, anti-TPO, or APAs), 34 RPL patients without autoAbs, and 58 healthy women with prior successful pregnancies and without autoantibodies. The levels of 25 (OH) D were measured using the sandwich ELISA technique.

Results

Our results showed insufficient serum 25(OH) D levels in study groups, with significantly lower levels observed in RPL patients with or without autoAbs compared to healthy women (P=0.0006). In addition, RPL patients with autoAbs had significantly lower 25(OH) D levels compared to RPL patients without autoAbs. We also found that serum levels of 25(OH) D in RPL patients with autoAbs were significantly lower than in RPL patients without autoAbs (20.51 ± 1.15 ng/ml Vs. 23.69 ± 0.74 ng/ml, P=0.0356). Further analysis indicated that RPL patients who were positive for ANA, and APAs, except anti-TPO, had significantly lower than 25(OH)D serum levels than RPL patients without autoAbs.

Conclusion

These findings suggest that RPL patients, especially those with APAs or ANA, have lower vitamin D levels compared to healthy women. This may indicate a link between maternal immune dysregulation due to vitamin D deficiency and the presence of autoantibodies in RPL.

Exploring the sophistications of unexplained recurrent pregnancy loss: A case-control study

BACKGROUND

Unexplained recurrent pregnancy loss (URPL) is a significant obstetric challenge affecting maternal health and well-being. Genetic factors, including mutations in the methylenetetrahydrofolate reductase (MTHFR) gene and elevated homocysteine levels, are increasingly recognized as contributors to URPL, though their precise roles remain complex. This study aimed to comprehensively explore these factors.

OBJECTIVES

This study examines the links between MTHFR gene polymorphisms (C677T and A1298C), plasma homocysteine levels, and URPL. It also aims to create a predictive model for URPL based on these factors.

DESIGN

A case-control study with Vietnamese women who had at least one pregnancy between January 2017 and June 2020, recruited from Medlatec Hospital and Hanoi Medical University. Participants included URPL cases (n = 128) and controls (n = 126).

METHODS

Participants were selected based on specific criteria. Main analyses identified the optimal multivariable logistic regression model for predicting URPL using Bayesian Model Averaging, with the optimal model chosen based on the highest Area Under the Curve (AUC) and posterior probability. A nomogram for clinical risk prediction was developed based on parameters from the optimal model.

RESULTS

URPL cases exhibited significantly higher plasma homocysteine levels (11.73 ± 6.08 µmol/L) compared to controls (7.64 ± 1.78 µmol/L), correlating with increased URPL risk (OR: 1.64, 95% confidence interval (CI): 1.41-1.96; p < 0.001). The MTHFR C677T variant showed strong associations with URPL, particularly the CT genotype (OR: 6.07, 95% CI: 3.00-12.93; p < 0.001) and TT genotype (OR: 14.62, 95% CI: 2.85-114.77; p = 0.003). Similarly, the A1298C variant demonstrated elevated URPL risk with the AC genotype (OR: 2.73, 95% CI: 1.34-5.78; p = 0.007) and CC genotype (OR: 12.43, 95% CI: 3.17-64.22; p = 0.001).

CONCLUSION

This study provides insights into the complex interplay of MTHFR gene mutations, elevated homocysteine levels, and URPL. Genetic testing and biomarker assessment may play a crucial role in customizing risk assessment and management strategies for women at risk of URPL.

Immunological Aspects of Infertility-The Role of KIR Receptors and HLA-C Antigen

The mechanisms of immune tolerance of a mother against an antigenically foreign fetus without a concomitant loss of defense capabilities against pathogens are the factors underlying the success of a pregnancy. A significant role in human defense is played by killer immunoglobulin-like receptor (KIR) receptors, which regulate the function of the natural killer (NK) cells capable of destroying antigenically foreign cells, virus-infected cells, or tumor-lesioned cells. A special subpopulation of NK cells called uterine NK cells (uNK) is found in the uterus. Disruption of the tolerance process or overactivity of immune-competent cells can lead to immune infertility, a situation in which a woman's immune system attacks her own reproductive cells, making it impossible to conceive or maintain a pregnancy. Since the prominent role of the inflammatory response in infertility, including KIR receptors and NK cells, has been postulated, the process of antigen presentation involving major histocompatibility complex (MHC) molecules (HLA) appears to be crucial for a successful pregnancy. Proper interactions between KIR receptors on female uNK cells and HLA class I molecules, with a predominant role for HLA-C, found on the surface of germ cells, are strategically important during embryo implantation. In addition, maintaining a functional balance between activating and inhibitory KIR receptors is essential for proper placenta formation and embryo implantation in the uterus. A disruption of this balance can lead to complications during pregnancy. The discovery of links between KIR and HLA-C has provided valuable information about the complexity of maternal-fetal immune interactions that determine the success of a pregnancy. The great diversity of maternal KIR and fetal HLA-C ligands is associated with the occurrence of KIR/HLA-C combinations that are more or less favorable for reproductive success.

A comprehensive Bayesian analysis assessing the effectiveness of lymphocyte immunotherapy for recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) affects 2%-5% of couples worldwide and remains a subject of debate regarding the effectiveness of lymphocyte immunotherapy (LIT) due to limited retrospective studies. We conducted a comprehensive Bayesian analysis to assess the impact of LIT on RSA. Using data from the Shenzhen Maternity and Child Healthcare Hospital (2001-2020, n = 2316), a Bayesian generalized linear model with predictive projection feature selection was employed. Our analysis revealed a significant improvement in live birth rates for RSA patients undergoing LIT. Notably, LIT had a greater impact compared to the other 85 factors considered. To mitigate research bias, we conducted a Bayesian meta-analysis combining our dataset with 19 previously reported studies (1985-2021, n = 4246). Additionally, we developed an empirical model highlighting the four key factors, which are the LIT result, age, paternal blood type, and anticardiolipin antibody. Younger age (19-27), paternal blood type B, and a positive anticardiolipin antibody (IgM) were associated with better therapeutic outcomes in LIT for RSA. These findings aid clinicians in identifying suitable candidates for LIT and improving treatment outcomes.

Decreased CD56+CD16-CD94+uNK cells in the mid-luteal phase in women with recurrent implantation failure are associated with IL-15 deficiency

PROBLEM

Whether the abnormal development of uterine natural killer (uNK) cells contributes to women with recurrent implantation failure (RIF) remains unclear.

METHOD OF STUDY

We characterized the development of uNK cells and peripheral blood NK cells (pbNK) in the mid-luteal phase in women with RIF (n = 31) and controls (n = 14) by flow cytometry. Endometrial IL-15 mRNA expression was studied by quantitative reverse transcription-PCR. The GSE58144 dataset was used to validate the correlation results.

RESULTS

We found decreased proportions of stage 4 CD56+CD16-CD94+ uNK cells (median: 9.56% vs. 17.78%, P .014) and increased proportions of stage 6 CD56+CD16+CD57+ uNK cells (median: 1.54% vs. 0.74%, P = .020) in the mid-luteal endometrium of women with RIF compared to fertile women. We also found that there was no quantitative correlation between uNK cells and the corresponding pbNK cell subpopulations (P > .05). In addition, IL-15 mRNA levels in the mid-luteal endometrium were positively correlated with the proportion of CD56+ uNK cells (r = .392, P = .008), especially with stage 4 uNK cell populations (r = .408, P = .005).

CONCLUSIONS

We showed that the proportion of stage 4 uNK cells decreased in the RIF group compared to controls, and the decrease in stage 4 uNK cells correlated positively with low IL-15 mRNA expression. We suggest that the reduced stage 4 uNK cells in women with RIF are associated with IL-15 deficiency.

Intrauterine perfusion of dexamethasone improves pregnancy outcomes in recurrent reproductive failure patients with elevated uterine natural killer cells. A retrospective cohort study

OBJECTIVE

To determine the effect of intrauterine perfusion of dexamethasone (DXM) on pregnancy outcomes in recurrent reproductive failure (RRF) patients with elevated uNK cells.

METHODS

This retrospective cohort study included 132 RRF patients with elevated uNK cells: 56 patients received DXM treatment and 76 patients refused it in the frozen-thawed embryo transfer cycles. To determine the efficacy of intrauterine perfusion of DXM, multivariate logistic regression models and diagnosis-based subgroup analysis were performed. We also compared the pregnancy outcomes of patients with different responsiveness to DXM treatment.

RESULTS

Intrauterine perfusion of DXM significantly improved clinical pregnancy rate (aOR: 3.188, 95% CI: 1.395-7.282, P = .006) and live birth rate (aOR: 3.176, 95% CI: 1.318-7.656, P = .010) in RRF patients with elevated uNK cells, but there was no significant association with miscarriage rate. Subgroup analysis revealed that intrauterine perfusion of DXM in patients with recurrent implantation failure (RIF) showed significant improvement in clinical pregnancy rate (aOR: 6.110, 95% CI: 1.511-24.713, P = .011) and live birth rate (aOR: 9.904, 95% CI: 1.963-49.968, P = .005), but there was insufficient evidence of benefit in recurrent pregnancy loss (RPL) patients. Additionally, uNK cell levels dropped to normal range was achieved in only 35.90% of RRF patients after DXM treatment, no significant difference was found in pregnancy outcomes among patients with different responsiveness to DXM treatment (all P > .05).

CONCLUSION

Intrauterine perfusion of DXM was a promising and effective treatment to enhance clinical pregnancy rate and live birth rate in RRF women with abnormally elevated uNK cells, and RIF patients are more likely to benefit than RPL patients.

Role of the CD40-CD40L expression level pathway in the diagnosis of unexplained recurrent pregnancy loss

BACKGROUND

Unexplained recurrent spontaneous pregnancy loss (URPL) lacks effective treatment and reliable early diagnosis and prediction. Immunologic dysfunction can be an underlying cause of recurrent pregnancy loss (RPL). Considering the regulatory role of CD40-CD40L in immune responses, we explored its clinical significance in URPL.

METHODS

The 108 women with URPL who were treated in Hebei Yanda Hospital from January 2020 to December 2022 were selected as study subjects, and another 108 healthy women who were not pregnant and matched with the age and body mass index of the study group were selected as the control group. CD40 and CD4 + CD25 + Treg cells in peripheral blood mononuclear cells (PBMCs) and CD40L in peripheral blood platelets were measured by flow cytometry. The predictive value of CD40-CD40L in URPL for the risk of RPL was determined by receiver operating characteristic (ROC) curves. The correlations of CD40-CD40L with CD4 + CD25 + Treg cells and serum pro-inflammatory factors were assessed by Pearson's analysis.

RESULTS

CD40 on the surface of PBMCs and CD40L on the surface of platelets were up-regulated in URPL patients. CD40 in combination with CD40L had high predictive value for the risk of RPL in URPL patients. Peripheral blood CD40-CD40L was positively linked to IL-17 and IL-23, and negatively to CD4 + CD25 + Treg cells and IL-10 in URPL patients.

CONCLUSIONS

The CD40-CD40L pathway expression in peripheral blood can help predict the risk of RPL in URPL patients.

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.

Events Leading to the Establishment of Pregnancy and Placental Formation: The Need to Fine-Tune the Nomenclature on Pregnancy and Gestation

Today, there is strong and diversified evidence that in humans at least 50% of early embryos do not proceed beyond the pre-implantation period. This evidence comes from clinical investigations, demography, epidemiology, embryology, immunology, and molecular biology. The purpose of this article is to highlight the steps leading to the establishment of pregnancy and placenta formation. These early events document the existence of a clear distinction between embryonic losses during the first two weeks after conception and those occurring during the subsequent months. This review attempts to highlight the nature of the maternal-embryonic dialogue and the major mechanisms active during the pre-implantation period aimed at "selecting" embryos with the ability to proceed to the formation of the placenta and therefore to the completion of pregnancy. This intense molecular cross-talk between the early embryo and the endometrium starts even before the blastocyst reaches the uterine cavity, substantially initiating and conditioning the process of implantation and the formation of the placenta. Today, several factors involved in this dialogue have been identified, although the best-known and overall, the most important, still remains Chorionic Gonadotrophin, indispensable during the first 8 to 10 weeks after fertilization. In addition, there are other substances acting during the first days following fertilization, the Early Pregnancy Factor, believed to be involved in the suppression of the maternal response, thereby allowing the continued viability of the early embryo. The Pre-Implantation Factor, secreted between 2 and 4 days after fertilization. This linear peptide molecule exhibits a self-protective and antitoxic action, is present in maternal blood as early as 7 days after conception, and is absent in the presence of non-viable embryos. The Embryo-Derived Platelet-activating Factor, produced and released by embryos of all mammalian species studied seems to have a role in the ligand-mediated trophic support of the early embryo. The implantation process is also guided by signals from cells in the decidualized endometrium. Various types of cells are involved, among them epithelial, stromal, and trophoblastic, producing a number of cellular molecules, such as cytokines, chemokines, growth factors, and adhesion molecules. Immune cells are also involved, mainly uterine natural killer cells, macrophages, and T cells. In conclusion, events taking place during the first two weeks after fertilization determine whether pregnancy can proceed and therefore whether placenta's formation can proceed. These events represent the scientific basis for a clear distinction between the first two weeks following fertilization and the rest of gestation. For this reason, we propose that a new nomenclature be adopted specifically separating the two periods. In other words, the period from fertilization and birth should be named "gestation", whereas that from the completion of the process of implantation leading to the formation of the placenta, and birth should be named "pregnancy".

An interplay of Progesterone, Leukemia Inhibitor Factor and Interleukin-6 in the window of implantation; Impact on fertility

BACKGROUND

The process of implantation is crucial for the initiation of conception and hence fertility. In addition to a number of factors, it is regulated by a cross talk of gonadotrophins [Luteinizing Hormone (LH), Follicle Stimulatory Hormone (FSH)], ovarian steroids [Estrogen (Et), Progesterone (Pt)] and cytokines [Leukemia inhibitory factor (LIF) and Interleukin 6 (IL6)]. These biomarkers are chief players of implantation.

OBJECTIVE

We aimed to explore the role of gonadotrophins (LH, FSH, LH/FSH ratio), ovarian steroids (Et, Pt) and cytokines (LIF, IL6) in the implantation process. This aim was achieved by comparing these hormones and cytokines in the fertile and infertile groups [Polycystic ovaries (PCOs), endometriosis, unexplained infertility (Uex-IF)] and finding their association in all study groups.

METHODS

A case control study conducted from October 2020-March 2023. A total of 135 infertile women (with PCOs, Uex-IF, and endometriosis) and 177 fertile women (matched for age and BMI) were selected. Levels of 'Et', 'Pt', 'LIF' and, 'IL6' were estimated using Enzyme Linked Immunosorbent Assay (ELISA). LH and FSH values were obtained from hospital desk records. The Independent Student'st-test was used to compare fertile and infertile groups. One-way ANOVA test was used to compare more than two groups, and Pearson's chi-square (χ2) test was employed to compare percentages of variables. Pearson correlation analysis was performed to assess the associations and correlations. A p value < 0.05 was considered statistically significant.

RESULTS

Significantly higher levels of LIF and IL6 were observed in fertile women compared to infertile women. Pt levels were significantly greater in the fertile group than in the infertile group. The FSH/LH ratio was significantly higher in the fertile group. Among infertile women, PCOs (71%) and Uex-IF (91%) exhibited lower Pt levels than the fertile controls (p < 0.01), but these levels remained within the reference range (RR). Among the fertile group (81%), levels of LIF within the RR were significantly higher compared to those with Uex-IF (49%) and females with endometriosis (37%). Moreover, the highest number of participants (57%) with Uex-IF exhibited IL6 levels significantly below the RR in comparison to the fertile group and infertile groups (PCOS and endometriosis). However, lower levels of IL6 were observed in women with Uex-IF. In the control group, LIF exhibited a significant positive correlation with IL6 (r = 0.370), Pt (r = 0.496), Et (r = 0.403), and LH (r = 0.428). Among women with PCOs, LIF showed a significant positive correlation with IL6 (r = 0.443), Pt (r = 0.607), and LH (r = 0.472). In cases of Uex-IF, LIF demonstrated a significant positive correlation with IL6 (r = 0.727). Females with endometriosis displayed a significant positive correlation between LIF and IL6 (r = 0.535) as well as Pt (r = 0.605). In fertile women, a positive correlation was observed between LH and IL6 (r = 0.197, p = 0.009), LIF (r = 0.428, p = 0.000), Pt (r = 0.238, p = 0.001), and Et (r = 0.356, p = 0.000). Furthermore, a positive correlation was found between LH and LIF (r = 0.472, p = 0.000) in women with PCOs.

CONCLUSION

Elevated levels of Pt were found to increase the production of LIF in fertile females. However, infertile females with PCOs and Uex-IF exhibited deficient levels of Pt, supporting its role as a biomarker for successful implantation in infertile women. These females showed decreased levels of gonadotropins as well as reduced LH/FSH ratio and diminished secretion of receptivity marker LIF, in addition to reduced Pt secretion. This suggests that reduced gonadotropin levels contribute to a lower LH/FSH ratio, resulting in decreased Pt secretion and ultimately leading to low levels of LIF, thereby causing impaired implantation in women with PCOs and Uex-IF. The exploration of low levels of LIF in patients with endometriosis requires further investigation. The significantly low levels of IL6 in the Uex-IF group elucidate the role of this cytokine in association with decreased Pt and LIF synthesis within this group.

Association of plasma folic acid, vitamin-B12 and homocysteine with recurrent pregnancy loss. "A case control study"

Objective

To investigate the relationship of serum homocysteine, folic acid, and vitamin-B12 levels with recurrent pregnancy loss (RPL).

Methods

A case-control study was conducted in the Department of Gynecology and Obstetrics, Dr. Ruth Pfau Civil Hospital, Karachi from July 2021 to June 2022. Total 124 participants were recruited from gynecology outpatient department after taking informed consent. The participants included 62 non-pregnant females with two or more consecutive unexplained RPLs and 62 healthy women having at least two successful deliveries without any pregnancy loss. Serum folic acid and vitamin-B12 levels were measured by chemiluminescent method and serum homocysteine was measured by enzyme-linked immunosorbent assay (ELISA). Comparison of quantitative variables with RPL cases and control was done by Mann-Whitney U-test (for non-normally distributed data) and independent sample t-test (for normally distributed data), while Pearson's chi-square test was used for the association of qualitative variables with RPL cases and control. Correlation of homocysteine with vitamin-B12 and folic acid was assessed in RPL cases.

Results

The median age of the study population was 27 (IQR 25-32) years. The median body mass index (BMI) was 26.25 (IQR 22-29) kg/m2. Cases had significantly lower serum folic acid (p-value=0.022), while vitamin-B12 was decreased in cases as compared to controls (p-value=0.295). Mean concentration of serum homocysteine was higher in RPL cases as compared to controls (p-value=0.094). There was significant association of serum vitamin B12 (p-value=0.001) and folic acid levels (p-value=0.004) with RPL. The homocysteine was not significantly correlated with vitamin-B12 (r=0.124, p=0.338) and folic acid (r=0.067, p=0.606) in the RPL group.

Conclusion

Reduced level of serum folic acid and vitamin B12 was significantly associated with RPL cases, while homocysteine was marginally raised however the difference was not significant. Folic acid and vitamin B12 supplementation before next pregnancy in RPL patients is likely to be beneficial in improving pregnancy outcomes.

Palmitic Acid Upregulates CD96 Expression to Mediate Maternal-Foetal Interface Immune Tolerance by Inhibiting Cytotoxic Activity and Promoting Adhesion Function in Human Decidual Natural Killer Cells

Decidual natural killer cells (dNK cells) are an essential component of the immune cells present at the maternal-foetal interface during early pregnancy, and they play a vital role in various physiological processes. Abnormalities in the ratio or function of dNK cells have been linked to recurrent miscarriages. CD96 has been previously shown to regulate NK cell function in the tumour microenvironment; however, its role and mechanism at the maternal-foetal interface remains unclear. The present study aimed to investigate the immunomodulatory role of CD96 in dNK cells and its function at the maternal-foetal interface. Immunofluorescence staining and flow cytometry were used to detect the expression of cellular markers such as CD96. Furthermore, the secretory function, adhesion-function-related molecules, and cell proliferation markers of CD96+ and CD96- dNK cells were detected using flow cytometry. In addition, we performed cell culture experiments via the magnetic bead sorting of NK cells to detect changes in the expression of the aforementioned functional molecules in dNK cells after the CD96 blockade. Furthermore, we examined the functional characteristics of dNK cells after palmitic acid treatment at a concentration of 10 μM. We also examined the changes in dNK cell function when subjected to the combined effect of palmitic acid and CD96 antagonists. The results indicated that CD96, TIGIT, CD155, and CD112 were highly expressed at the maternal-foetal interface, with dNK cells predominantly expressing CD96, whereas TIGIT was mainly expressed on T cells, and CD155 and CD112 were mainly present in metaphase stromal and trophoblast cells. CD96+ dNK cells displayed low cytotoxic activity and a high adhesion phenotype, which mediated the immunosuppressive effect on dNK cells at the maternal-foetal interface. Palmitic acid upregulated CD96 expression on the surface of dNK cells in the coculture system, inhibiting dNK cell activity and increasing their adhesion molecule expression. CD96 antagonist treatment blocked the inhibitory effect of trophoblasts on dNK cells, resulting in enhanced cytokine secretion and reduced adhesion. The results of this study provide valuable insight into the immunomodulatory role of CD96 in dNK cells and its mechanism at the maternal-foetal interface, particularly in metaphase NK cells. This study sheds light on the mechanisms of immune regulation at the maternal-foetal interface and their implications for the study of recurrent miscarriages of unknown origin.

Identification and verification of diagnostic biomarkers in recurrent pregnancy loss via machine learning algorithm and WGCNA

Background

Recurrent pregnancy loss defined as the occurrence of two or more pregnancy losses before 20-24 weeks of gestation, is a prevalent and significant pathological condition that impacts human reproductive health. However, the underlying mechanism of RPL remains unclear. This study aimed to investigate the biomarkers and molecular mechanisms associated with RPL and explore novel treatment strategies for clinical applications.

Methods

The GEO database was utilized to retrieve the RPL gene expression profile GSE165004. This profile underwent differential expression analysis, WGCNA, functional enrichment, and subsequent analysis of RPL gene expression using LASSO regression, SVM-RFE, and RandomForest algorithms for hub gene screening. ANN model were constructed to assess the performance of hub genes in the dataset. The expression of hub genes in both the RPL and control group samples was validated using RT-qPCR. The immune cell infiltration level of RPL was assessed using CIBERSORT. Additionally, pan-cancer analysis was conducted using Sangerbox, and small-molecule drug screening was performed using CMap.

Results

A total of 352 DEGs were identified, including 198 up-regulated genes and 154 down-regulated genes. Enrichment analysis indicated that the DEGs were primarily associated with Fc gamma R-mediated phagocytosis, the Fc epsilon RI signaling pathway, and various metabolism-related pathways. The turquoise module, which showed the highest relevance to clinical symptoms based on WGCNA results, contained 104 DEGs. Three hub genes, WBP11, ACTR2, and NCSTN, were identified using machine learning algorithms. ROC curves demonstrated a strong diagnostic value when the three hub genes were combined. RT-qPCR confirmed the low expression of WBP11 and ACTR2 in RPL, whereas NCSTN exhibited high expression. The immune cell infiltration analysis results indicated an imbalance of macrophages in RPL. Meanwhile, these three hub genes exhibited aberrant expression in multiple malignancies and were associated with a poor prognosis. Furthermore, we identified several small-molecule drugs.

Conclusion

This study identifies and validates hub genes in RPL, which may lead to significant advancements in understanding the molecular mechanisms and treatment strategies for this condition.

Immune Checkpoints in Recurrent Pregnancy Loss: New Insights into a Detrimental and Elusive Disorder

Recurrent pregnancy loss (RPL) refers to two or more miscarriages before 20 weeks gestation. Its prevalence is 1-2%; its pathogenesis remains unexplained in more than 50% of cases, in which the cause is thought to be abnormal immune activity during placentation leading to a lack of pregnancy-induced immune tolerance. It is unknown whether immune activity is deranged in the endometrium of women with RPL. We studied the gene expression and the quantitative tissue protein levels of three immune checkpoints (CD276, which enhances cytotoxic T-cell activity, cytotoxic T-lymphocyte-associated antigen-4 [CTL-4], which reduces Th1 cytokine production, and lymphocyte activation gene-3 [LAG-3], which shows suppressive activity on Tregs and CD4+ T-cells) in endometrial samples from 27 women with unexplained RPL and in 29 women with dysfunctional uterine bleeding and previous uneventful pregnancies as controls. RNA isolation, real-time PCR, protein isolation, and ELISA were performed. CD276 gene expression and protein tissue levels were significantly lower in the endometrium of the RPL group than in the controls, whereas both CTL-4 and LAG-3 were significantly higher. This difference suggests defective endometrial immune regulation and overactivation of immune response in women with a history of RPL, at least in relation to controls with dysfunctional uterine bleeding and previous normal reproductive history.

Radiomics optimizing the evaluation of endometrial receptivity for women with unexplained recurrent pregnancy loss

Background

The optimization of endometrial receptivity (ER) through individualized therapies has been shown to enhance the likelihood of successful gestation. However, current practice lacks comprehensive methods for evaluating the ER of patients with recurrent pregnancy loss (RPL). Radiomics, an emerging AI-based technique that enables the extraction of mineable information from medical images, holds potential to offer a more objective and quantitative approach to ER assessment. This innovative tool may facilitate a deeper understanding of the endometrial environment and enable clinicians to optimize ER evaluation in RPL patients.

Objective

This study aimed to identify ultrasound radiomics features associated with ER, with the purpose of predicting successful ongoing pregnancies in RPL patients, and to assess the predictive accuracy of these features against regular ER parameters.

Methods

This retrospective, controlled study involved 262 patients with unexplained RPL and 273 controls with a history of uncomplicated full-term pregnancies. Radiomics features were extracted from ultrasound endometrial segmentation images to derive a radiomics score (rad-score) for each participant. Associations between rad-scores, baseline clinical variables, and sonographic data were evaluated using univariate and multivariate logistic regression analyses to identify potential indicators of RPL. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive accuracy of the rad-score and other identified indicators in discriminating RPL cases. Furthermore, the relationships between age and these identified indicators were assessed via Pearson correlation analysis.

Results

From the 1312 extracted radiomics features, five non-zero coefficient radiomics signatures were identified as significantly associated with RPL, forming the basis of the rad-score. Following multivariate logistic regression analysis, age, spiral artery pulsatility index (SA-PI), vascularisation index (VI), and rad-score emerged as independent correlates of RPL (all P<0.05). ROC curve analyses revealed the superior discriminative capability of the rad-score (AUC=0.882) over age (AUC=0.778), SA-PI (AUC=0.771), and VI (AUC=0.595). There were notable correlations between age and rad-score (r=0.275), VI (r=-0.224), and SA-PI (r=0.211), indicating age-related variations in RPL predictors.

Conclusion

This study revealed a significant association between unexplained RPL and elevated endometrial rad-scores during the WOI. Furthermore, it demonstrated the potential of rad-scores as a promising predictive tool for successful ongoing pregnancies in RPL patients.

Identification of novel biomarkers and immune infiltration features of recurrent pregnancy loss by machine learning

Recurrent pregnancy loss (RPL) is a complex reproductive disorder. The incompletely understood pathophysiology of RPL makes early detection and exact treatment difficult. The purpose of this work was to discover optimally characterized genes (OFGs) of RPL and to investigate immune cell infiltration in RPL. It will aid in better understanding the etiology of RPL and in the early detection of RPL. The RPL-related datasets were obtained from the Gene Expression Omnibus (GEO), namely GSE165004 and GSE26787. We performed functional enrichment analysis on the screened differentially expressed genes (DEGs). Three machine learning techniques are used to generate the OFGs. A CIBERSORT analysis was conducted to examine the immune infiltration in RPL patients compared with normal controls and to investigate the correlation between OFGs and immune cells. Between the RPL and control groups, 42 DEGs were discovered. These DEGs were found to be involved in cell signal transduction, cytokine receptor interactions, and immunological response, according to the functional enrichment analysis. By integrating OFGs from the LASSO, SVM-REF, and RF algorithms (AUC > 0.880), we screened for three down-regulated genes: ZNF90, TPT1P8, FGF2, and an up-regulated FAM166B. Immune infiltration study revealed that RPL samples had more monocytes (P < 0.001) and fewer T cells (P = 0.005) than controls, which may contribute to RPL pathogenesis. Additionally, all OFGs linked with various invading immune cells to varying degrees. In conclusion, ZNF90, TPT1P8, FGF2, and FAM166B are potential RPL biomarkers, offering new avenues for research into the molecular mechanisms of RPL immune modulation and early detection.