Pathogenetic factors involved in recurrent pregnancy loss from multiple aspects

Alpha-lipoic acid upregulates the PPARγ/NRF2/GPX4 signal pathway to inhibit ferroptosis in the pathogenesis of unexplained recurrent pregnancy loss

Aim

With unknown etiology and limited treatment options, unexplained recurrent pregnancy loss (URPL) remains a thorny problem. Ferroptosis, a newly identified type of cell death, has been shown to be crucial in the development in reproductive disorders. This study aims to explore the specific mechanism of ferroptosis in URPL and to uncover whether alpha-lipoic acid (ALA) can inhibit ferroptosis, and then exert a protective effect in URPL.

Method

The decidua tissues of URPL and control patients who actively terminated pregnancy were collected. The CBA/J × DBA/2 murine models of URPL were established, and were randomly treated with peroxisome proliferator activated receptor γ (PPARγ) agonists (Rosiglitazone) and ALA. The CBA/J × BALB/c murine models of normal pregnancy were intraperitoneally injected with PPARγ inhibitors (T0070907). Here, we used reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH)/GSSG, and FeRhoNox-1 analysis to detect the level of ferroptosis. We used quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analysis to evaluate the mRNA level of PPARγ. Besides, western blot and immunofluorescence were utilized to test the expression profile of PPARγ/nuclear factor erythroid 2-related factor 2 (NRF2)/glutathione peroxidase 4 (GPX4).

Results

In this study, we found that iron deposition was increased in the decidual tissue of patients with URPL. Additionally, the changes in cell morphology, the level of ROS, MDA, GSH, and the expression of ferroptosis marker proteins NRF2/GPX4 confirmed activated ferroptosis in URPL. Besides, bioinformatics analysis combined with experiments confirmed that PPARγ was critical in triggering NRF2/GPX4 pathway in URPL. Furthermore, URPL mouse models were established, and the results showed that PPARγ/NRF2/GPX4-mediated ferroptosis was also significantly increased, which could be mitigated by ALA treatment.

Conclusion

Overall, these findings suggest that ferroptosis may play an important role in URPL, and ALA might be a promising therapeutic drug for improving pregnancy outcomes in URPL via targeting the PPARγ/NRF2/GPX4 pathway.

Gene Expression Levels of CSF-1 and CSF-1R Endometrial under The Influence of Prolactin Level in Unexplained Miscarriage: A Case-Control Study

BACKGROUND

Hormones such as prolactin, by influencing expression of the endometrial genes, play a pivotal role in embryo implantation and development. The present study aimed to evaluate serum level of prolactin and its effect on altering expression level of colony-stimulating factor-1 (CSF-1) and colony-stimulating factor-1 receptor (CSF-1R) genes in endometrial tissue during in vitro fertilization (IVF) pregnancy in the infertile women and recurrent pregnancy loss (RPL), compared to fertile women, who lost their pregnancies at gestational age <20 weeks.

MATERIALS AND METHODS

In this case-control study, 40 infertile women, 40 IVF pregnant women with RPL and 40 fertile women who lost their pregnancies at <20 weeks of gestation for unknown reasons were selected. Prolactin serum level was assessed using ELISA technique and expression of CSF-1 and CSF-1R genes was determined in endometrial tissue, using quantitative reverse transcription polymerase chain reaction (qRT-PCR).

RESULTS

Mean prolactin level of the infertile group was 24.38 ± 1.43 ng/mL and it had statistically significant relationship with the fertile group (P<0.001). Expression level of the CSF-1 and CSF-1R genes were higher in the fertile than infertile groups by 2.88 times (P<0.0001) and 2.64 times (P<0.0001), while it was respectively 2.28 (P<0.0001) and 1.69 (P<0.0001) times higher compared to the RPL group. Risk factors for pregnancy loss, such as aging, increased body mass index (BMI), smoking and diabetes caused decreasing changes in gene expression (CSF-1 and CSF-1R ) and the differences were statistically significant, except in the infertile group.

CONCLUSION

The present study showed a significant relationship of CSF-1 and CSF-1R expression levels with pregnancy loss. Risk factors such as aging, obesity, smoking and diabetes decreased both genes expression levels.

Dominant immune cells in pregnancy and pregnancy complications: T helper cells (TH1/TH2, TH17/Treg cells), NK cells, MDSCs, and the immune checkpoints

Pregnancy problems including recurrent pregnancy loss, repeated implantation failure and pre-eclampsia  are common problems in the reproductive ages. Different reasons such as genetic, immunological, and environmental agents and also infections could develop these complications. In those cases in which the cause of the abortion is diagnosed, the chance of a successful pregnancy is increased by eliminating defective factors. However, in patients with unknown causes, there may be an imbalance in immune cells pattern. As a matter of fact, an inappropriate immune response is often associated with a failed pregnancy. Hence, the focus of treatment is to increase tolerance, not to suppress maternal immune system. These findings are linked to an elevated number of Treg cells and immune checkpoints through normal pregnancy. The present review discusses the balance of myeloid-derived suppressor cells, natural killer cells, T cells, and immune checkpoints, and also targeting them to maintain pregnancy and prevent associated complications.

Epigenetic and transcriptomic characterization of maternal-fetal interface in patients with recurrent miscarriage via an integrated multi-omics approach

Recurrent miscarriage (RM) occurs in 2.5 % of women aiming at childbirth, with unknown etiology in half of the cases. To identify the molecular features, an integrative study combining bioinformatics and multi-omics from GEO database was performed in these patients. Two datasets (GSE43256 and GSE73025) were integrated to indicate 1657 differentially expressed genes (DE-genes) in villus of females with RM. DE-genes in villus of females with RM mainly focused on cell growth and development. On the other hand, 230 DE-genes in decidua of RM patients were retrieved from GSE113790, and the DE-genes were involved in diverse functions, including transport of nutrients, immune response, extracellular matrix remodeling, and angiogenesis. Additionally, the results of immunologic signatures indicated that immune regulation played roles in both decidua and villus of RM. Interestingly, C1q and TNF related 7 (C1QTNF7), acquired from the intersection of decidua and villus datasets, is crucial in maintaining immune homeostasis, so is its upstream miRNA (miR-149-3p). The enhanced expression of C1QTNF7 in macrophages might inhibit the proliferation and migration of trophoblasts, and further result in pregnancy loss. The present study suggests C1QTNF7 might be a new target for the diagnosis and treatment of RM, but more basic researches are further required to illustrate its mechanism in RM.

Understanding recurrent pregnancy loss: recent advances on its etiology, clinical diagnosis, and management

Recurrent pregnancy loss (RPL) has become an important reproductive health issue worldwide. RPL affects about 2%-3% of reproductive-aged women, and makes serious threats to women's physical and mental health. However, the etiology of approximately 50% of RPL cases remains unknown (unexplained RPL), which poses a big challenge for clinical management of these patients. RPL has been widely regarded as a complex disease where its etiology has been attributed to numerous factors. Heretofore, various risk factors for RPL have been identified, such as maternal ages, genetic factors, anatomical structural abnormalities, endocrine dysfunction, prethrombotic state, immunological factors, and infection. More importantly, development and applications of next generation sequencing technology have significantly expanded opportunities to discover chromosomal aberrations and single gene variants responsible for RPL, which provides new insight into its pathogenic mechanisms. Furthermore, based upon patients' diagnostic evaluation and etiologic diagnosis, specific therapeutic recommendations have been established. This review will highlight current understanding and recent advances on RPL, with a special focus on the immunological and genetic etiologies, clinical diagnosis and therapeutic management.

Characterization of placental and decidual cell development in early pregnancy loss by single-cell RNA sequencing

Background

Early pregnancy loss (EPL) presents as sporadic or recurrent miscarriage during the first trimester. In addition to chromosomal defects, EPL may result from impairment of the placental-decidual interface at early gestational age due to gene-environmental interactions.

Methods

To better understand the pathogenesis associated with this impairment, cell development in chorionic villi and decidua of different forms of EPL (sporadic or recurrent) was investigated with single-cell RNA sequencing and compared to that of normal first-trimester tissue.

Results

Unique gene expression signatures were obtained for the different forms of EPL and for normal tissue and the composition of placental and decidual cell clusters in each form was established. In particular, the involvement of macrophages in the EPL phenotypes was identified revealing an immunoactive state.

Conclusion

Differential gene expression and unique marker genes among cell clusters from chorionic villi and decidua of miscarried and normal pregnancies, may lead to identification of biomarker for EPL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00904-5.

Study of association between different microRNA variants and the risk of idiopathic recurrent pregnancy loss

AIM

Recurrent pregnancy loss (RPL) is a common reproductive disorder among women and a major cause of infertility among them; however, the underlying causes of RPL remain unknown which have led to great difficulties and complications in the treatment. MicroRNAs (miRNA) have been shown to be a potential diagnosis tools in different reproductive disorders. This study aimed to investigate the association of four different miRNA variants with the risk of idiopathic RPL (iRPL).

METHODS

A total of 450 women including 225 patients and 225 controls were recruited in this study. DNA was extracted, and genotyped by PCR method. Haplotype analysis, as well as linkage disequilibrium between SNPs, was performed.

CONCLUSION

This study suggested that rs4636297, rs41291957, and rs353292, but not rs531564 can play a risk factor role for iRLP.

Association between serum vitamin D level during pregnancy and recurrent spontaneous abortion: a systematic review and meta-analysis

PROBLEM

Previous studies had shown that there might be an association between serum vitamin D concentrations and the occurrence of recurrent spontaneous abortion (RSA). However, the conclusions remained controversial. The objective of this study was to systematically review the evidence for an epidemiological association between vitamin D and RSA.

METHOD OF STUDY

The literature search was performed in the following databases: PubMed, Web of Science, Embase and Chinese databases. The I² statistic was used to evaluate heterogeneity. Effect sizes were calculated using fixed or random effects models, including standardized mean difference (SMD), odds ratios (OR) and their 95% confidence intervals (95%CI). Then we performed subgroup analysis, sensitivity analysis and publication bias analysis.

RESULTS

Fourteen studies from five countries were included. Based on the results, patients with RSA had lower vitamin D levels than controls (SMD = -1.48, 95%CI: -2.01, -0.94, P<0.001), and pregnant women with vitamin D deficiency (VDD) had a higher risk of developing RSA (OR = 4.02, 95%CI: 2.23, 7.25, P<0.001). There was remarkable heterogeneity between studies (I² _SMD = 97.3%, P<0.001; I² _OR = 82.2%, P<0.001). The results of the subgroup analysis suggested that heterogeneity may be caused by the assay method, age and region. Sensitivity analysis showed the analysis results were robust.

CONCLUSION

Patients with RSA had lower serum vitamin D levels than normal pregnant women, and pregnant women with VDD might be at higher risk for RSA. This article is protected by copyright. All rights reserved.

Evaluation of Th17 and Treg cytokines in patients with unexplained recurrent pregnancy loss

Background and Aim

The Th17/Treg balance in peripheral blood and reproductive tissues may have a role in the etiology of unexplained recurrent pregnancy loss (URPL). In this study, we evaluated the major cytokine of Treg cells transforming growth factor-beta (TGF-β), and their specific transcription factor Forkhead box P3 (FOXP3), as well as the most highlighted cytokine of Th17 cells (interleukin [IL]-17A) in both URPL patients and healthy women.

Methods

Samples were extracted from the peripheral blood, endocervix, endometrium, and vagina of 14 patients with URPL and 12 normal non-pregnant women as a control (normal) group. Quantitative reverse transcription polymerase chain reaction was used to determine gene expression. Enzyme-linked immunosorbent assay was used to determine the levels of cytokines in the serum and cervicovaginal fluid.

Results

We found that in the URPL group, FOXP3 gene expression was considerably higher in peripheral blood than in the normal group (P=0.043). TGF-β levels in the cervicovaginal fluid were different in the URPL and normal groups (P=0.015). In comparison to the control group, women with URPL had significantly greater IL-17 gene expression in the peripheral blood (P=0.01).

Conclusion

Lower TGF-β levels in the cervicovaginal fluid of patients compared to controls may be related with increased IL-17 and FOXP3 mRNA levels in patients with URPL. Dysregulation of local immune responses in reproductive tissues may represent dysregulation of systemic regulatory immunological responses in the pathogenesis of URPL.

Relevance for Patients

Dysregulation of immune responses may play a role in the pathogenesis of URPL at least in some patients with URPL. We conclude that the breakdown of tolerance in the local immune responses is more critical than the breakdown of tolerance in systemic tolerance in the pathogenesis of URPL. Therefore, modulating immune responses in the endometrium and decidua may be the focus of future therapeutic approaches in URPL. The impact of seminal plasma on the expansion of Tregs may provide a novel therapeutic intervention that has already been used in assisted reproductive technologies. Therefore, we suggest that transvaginal TGF-β in women with URPL may induce maternal tolerance which leads to the successful pregnancy.

Allogeneic lymphocytes immunotherapy in female infertility: Lessons learned and the road ahead

The endometrium is an essential tissue in the normal immunologic dialogue between the mother and the conceptus, which is necessary for the proper establishment and maintenance of a successful pregnancy. It's become evident that the maternal immune system plays a key role in the normal pregnancy's initiation, maintenance, and termination. In this perspective, the immune system contributes to regulating all stages of pregnancy, thus immunological dysregulation is thought to be one of the major etiologies of implantation failures. Many researchers believe that immune therapies are useful tactics for improving the live births rate in certain situations. Lymphocyte immunotherapy (LIT) is an active form of immunotherapy that, when used on the relevant subgroups of patients, has been shown in multiple trials to dramatically enhance maternal immunological balance and pregnancy outcome. The primary goal of LIT is to regulate the immune system in order to create a favorable tolerogenic immune milieu and tolerance for embryo implantation. However, there are a plethora of influential factors influencing its therapeutic benefits that merit to be addressed. The objective of our study is to discuss the mechanisms and challenges of allogeneic LIT.

Immunohistochemical Evaluation of CD3, CD4, CD8, and CD20 in Decidual and Trophoblastic Tissue Specimens of Patients with Recurrent Pregnancy Loss

Recurrent miscarriages affect up to 5% of couples. CD3⁺ (T-lymphocytes), CD4⁺ (helper T-lymphocytes), CD8⁺ (cytotoxic T-lymphocytes), and CD20⁺ (B-lymphocytes) cells may participate in the pathophysiology of recurrent pregnancy loss (RPL). The aim of this study was to investigate the complicity of these molecules in RPL. The experimental specimens were obtained from 20 females who underwent miscarriages in the first gestational trimester, while the control group’s specimens consisted of 20 females who proceeded with voluntary pregnancy termination during the same period. Tissue samples were taken from the decidua basalis, decidua parietalis, and trophoblast (placental chorionic villi) and were studied using immunohistochemical methods. Monoclonal antibodies were used against CD3, CD4, CD8, and CD20 cells. The lymphocyte levels in the decidua parietalis displayed profound disparities among the two groups. The decidua basalis and trophoblast exhibited almost the same disparities regarding positive CD cells. The comparison of CD4⁺ and CD8⁺ cells in the endometrial tissue revealed a significant difference between the two groups of study. The analysis uncovered a strong relationship between RPL and the presence of CD3⁺, CD4⁺, CD8⁺, and CD20⁺ cells in the decidua parietalis tissue. The number of positive T cells was decreased in the decidual basalis and chorionic villi, proving that their absence significantly disrupts the balance of the immunological environment.

Evaluation of the Effects of 1,25VitD3 on Inflammatory Responses and IL-25 Expression

VitD3 may contribute to a successful pregnancy through modulation of immune responses, so VitD3 deficiency may have a role in the immunopathogenesis of unexplained recurrent spontaneous abortion (URSA). However, the mechanisms of immunomodulatory actions of VitD3 in decreasing the risk of recurrent spontaneous abortion have not been understood well.

Objective: The purpose of this research was to investigate the influence of 1,25VitD3 on IL-25 and related cytokines of Th17 cells including IL-17A, IL-6, and IL-23 in peripheral blood mononuclear cells of healthy women as a control group and women with unexplained recurrent spontaneous abortion.

Method: Isolation of peripheral blood mononuclear cells (PBMCs) was performed from peripheral blood of the subjects of the studied groups (20 women with URSA as a case group, and 20 control women). The effects of 1,25VitD3 (50 nM, for 24 h) on the studied parameters were evaluated and were compared to the positive and negative controls in vitro. Flow cytometry analysis was used to determine the percentages of regulatory T cells and Th17 cells. For gene expression measurement and cytokines assay, real-time PCR and ELISA were carried out.

Results: The proportion of Th17 cells in women with URSA was considerably higher than in the control group. IL-25 mRNA and protein levels in cultured PBMCs from women with URSA were lower than the controls. 1,25VitD3 increased IL-25 expressions at both the protein and mRNA levels in PBMCs from women with URSA relative to the control group. Additionally, 1,25VitD3 treatment not only significantly decreased the percentage of Th17 cells frequency but also reduced expressions of IL-6, IL-17A, and IL-23 in PBMCs from women with URSA.

Conclusion: 1,25VitD3 may diminish inflammatory responses cells via downregulation of IL-25 expression. It could be an interesting subject for future researches in the field of the immunopathology of URSA to identify molecular pathways in URSA treatment.

Immunopharmacological properties of VitD3: 1,25VitD3 modulates regulatory T cells and Th17 cells and the cytokine balance in PBMCs from women with unexplained recurrent spontaneous abortion [URSA]

BACKGROUND

VitD3 may contribute to a successful pregnancy through modulation of immune responses, so VitD3 deficiency may have a role in the immunopathogenesis of unexplained recurrent spontaneous abortion [URSA]. However, the mechanisms of immunomodulatory actions of VitD3 in decreasing the risk of recurrent spontaneous abortion have not been understood well.

OBJECTIVE

The purpose of this research was to investigate the influence of 1,25VitD3 on regulatory T cells /Th17 axis, the gene expressions and concentrations of related cytokines including, TGF-β, IL-10, IL-6, IL-23, and IL-17A in peripheral blood mononuclear cells [PBMCs] of healthy women as a control group and women with URSA.

METHOD

Isolation of PBMCs was performed from peripheral blood of the subjects of the studied groups [20 women with URSA as a case group, and 20 control women]. The effects of 1,25VitD3 [50 nM, for 24 hours] on the studied parameters were evaluated and were compared to the positive and negative controls in vitro. Flow cytometry analysis was used to determine the percentages of regulatory T cells and Th17 cells. For gene expression measurement and cytokines assay, Real-time PCR and ELISA were carried out.

RESULTS

The proportion of regulatory T cells was markedly lower, while the proportion of Th17 cells in women with URSA was considerably higher than in the control group [P=0.01, P=0.01]. The ratio of the frequency of Tregs to the baseline [1,25VitD3/Untreated] increased, while the ratio of the frequency of Th17 cells to the baseline decreased in women with URSA relative to the controls [P= 0.01, P=0.04]. 1,25VitD3 increased IL-10 expressions at both the protein and mRNA levels in PBMCs in women with URSA relative to the control group [P=0.0001, P=0.04]. TGF-β levels in the cultured supernatants decreased significantly in the case group in the presence of 1,25VitD3 relative to the controls [P=0.03]. 1,25VitD3 treatment also significantly decreased gene expressions of IL-6, IL-17A, and IL-23 in PBMCs of women with URSA [P=0.01, P=0.001, P=0.0005], as well as the levels of those cytokines in cell culture supernatants [P=0.03, P=0.02, P=0.01, respectively] in women with URSA relative to the controls.

CONCLUSION

According to the findings of this research, modulation of immune responses by 1,25VitD3 is accomplished by strengthening Tregs function and inhibiting inflammatory responses of Th17 cells which may have a positive impact on pregnancy outcome. Thus, as an immunomodulating agent, VitD3 may be effective in reducing the risk of URSA.

Tumor necrosis factor inhibitors as therapeutic agents for recurrent spontaneous abortion (Review)

Recurrent spontaneous abortion (RSA) is a troublesome pregnancy disorder that manifests as sequential early pregnancy losses; its causes are diverse and complex. Among the known possible causes of RSA, the development of an immune disorder in response to the embryo appears to be the most pronounced. The imbalance between immune rejection and immune tolerance contributes to pregnancy loss in females with RSA, wherein the abnormal ratio of T helper (Th)1 cell‑related cytokines [predominantly tumor necrosis factor (TNF)‑α] and Th2 cell‑related cytokines is a strong risk factor for RSA. TNF‑α is a pro‑inflammatory cytokine and TNF inhibitors have been effective in the treatment of various autoimmune diseases, such as ankylosing spondylitis, and inflammatory diseases, such as ulcerative colitis. Based on their immunomodulatory properties, TNF inhibitors have been used in the treatment of RSA to reduce the immune rejection rate and improvement in pregnancy outcomes has been observed in females suffering from RSA who were treated with TNF inhibitors. The aim of the present review was to interpret the involvement of TNF‑α in the immunological disorder underlying RSA and summarize the clinical outcomes of TNF inhibitor treatment in patients with RSA.

Evaluation of the Effects of 1,25 Vitamin D3 on Regulatory T Cells and T Helper 17 Cells in Vitamin D-deficient Women with Unexplained Recurrent Pregnancy Loss

BACKGROUND

Vitamin D insufficiency and deficiency can be associated with adverse effects on pregnancy outcomes, which may include recurrent pregnancy loss through the mechanisms that are yet unknown. The aim of this study was to evaluate the effect of 1,25VitD3 on regulatory T cells (Tregs) and T helper17 (Th17) cell populations In vitro in unexplained recurrent pregnancy loss (URPL) patients and healthy women.

METHODS

Samples from 20 non-pregnant women with a history of URPL were compared to 20 normal non-pregnant women. Peripheral blood mononuclear cells (PBMC) were divided into 3 wells for each subject: in the presence of 1, 25 VitD3 (50 nM, for 16 hours), PHA (positive control) (10μM), and without any treatment (as a baseline or negative control). The percentage of regulatory T cells and Th17 cells was measured by flow cytometry at baseline and then after cell culture experiments.

RESULTS

Our study indicated that the percentage of Tregs in patients with URPL was significantly lower than the control group (2.42 ± 0.27 vs. 3.41 ± 0.29, P= 0.01). The percentage of Th17 cells was significantly greater in URPL patients compared to the control group (2.91 ± 0.33 vs. 1.18± 0.15, P=0.001). 1, 25VitD3 treatment significantly increased the percentage of Tregs from the baseline in the URPL group compared to that in the control group (1.23 ± 0.03 vs. 1.00 ± 0.03, P= 0.01).

CONCLUSION

Vitamin D deficiency may be a contributor to recurrent pregnancy loss and suggests supplementation of women with Vit D pre-pregnancy may be protective against URPL.

Hypoxia-induced DEC1 mediates trophoblast cell proliferation and migration via HIF1α signaling pathway

In early pregnancy, hypoxia is a typical extrinsic factor that regulates EVT functions including proliferation, migration and invasion which are essential for a successful pregnancy. Human differentiated embryonic chondrocyte-expressed gene 1 (DEC1), a hypoxia-regulated gene, has been reported to be overexpressed in several types of cancers. Given that the placenta and the cancer share several similarities with respect to their capacity to proliferate and invade adjacent tissues, we focused on the role of DEC1 on trophoblast function in a physiologically hypoxic environment, which may be associated with unexplained recurrent spontaneous abortion (URSA).In our study, we measured the expression of HIF-1α and DEC1 in first-trimester villi through real-time-PCR (RT-PCR) and immunohistochemical analysis. in vitro, DEC1 expression was downregulated in trophoblast cells via DEC1-specific shRNA plasmid transfection. The expression of DEC1 and HIF-1α was detected via western blotting and RT-PCR analysis. The proliferation and migration of HTR-8/SVneo cells were assayed using CCK-8 and Transwell migration assays, respectively.Our results indicated that the expression of DEC1 was significantly reduced in villi of URSA compared to that in normal pregnant women. in vitro, hypoxia induced the expression of HIF-1ɑ and DEC1 and upregulated proliferation and migration of the HTR-8/SVneo cells. Knockdown of DEC1 inhibited proliferation and migration of HTR-8/SVneo cells exposure to hypoxia. Furthermore, inhibition of HIF1α expression resulted in a significant decrease in DEC1. These findings illustrate that hypoxia-induced DEC1 expression promotes trophoblast cell proliferation and migration through the HIF1α signaling pathway, which plays an important role during placentation.

Genome wide methylation analysis to uncover genes related to recurrent pregnancy loss

BACKGROUND

Recurrent pregnancy loss (RPL) refers to two or more consecutive spontaneous abortion before 24 weeks of gestation, representing 1% of couples of childbearing age. Epigenetic factors including dysregulation of DNA methylation of some genes may play a role in RPL.

OBJECTIVE

To identify RPL related genes modulated by DNA methylation expressed in decidua and blood.

METHODS

Three decidua samples each from RPL patients and normal controls were recruited to perform genome-wide bisulfite sequencing (GWBS) and transcriptome sequencing. Based on the above results, 22.52 kb of differential methylation regions (DMRs) from 17 genes were verified by bisulfite sequencing PCR at specific region (Hi-MethylSeq) in another 15 decidua (7RPL vs. 8 Controls) and 13 blood (5RPL vs. 8 Controls) samples.

RESULTS

23 genes showed significantly differential cytosine methylation status and distinct expression level between PRL patients and healthy controls synergistically. Three signaling pathways were found to be shared between genes with both hypomethylated differential methylation regions (DMR) and upregulated differential gene expression (DGE). The results from Hi-MethylSeq showed that the hypermethylation of SGK1 in both blood and decidua samples in RPL patients, which was consistent to its lower expression in endometrium reported earlier. SGK3 and CREB5 also showed modulated methylation level in RPL decidua.

CONCLUSION

Our finding supported that aberrant methylation of SGK1 and CREB5 could be a cause of the dysregulation of these gens in the endometrium, which is one of cause of reproductive failure. The function of SGK3 in reproduction system deserves further investigation.

NLRP3 Inflammasome and Its Critical Role in Gynecological Disorders and Obstetrical Complications

Inflammasomes, intracellular, multimeric protein complexes, are assembled when damage signals stimulate nucleotide-binding oligomerization domain receptors (NLRs). Several inflammasomes have been reported, including the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), NLRP1, NLRP7, ice protease-activating factor (IPAF), absent in melanoma 2 (AIM2) and NLR family CARD domain-containing protein 4 (NLRC4). Among these inflammasomes, the NLRP3 inflammasome is the most well-studied in terms of structure and function. Unlike other inflammasomes that can only be activated by a finite number of pathogenic microorganisms, the NLRP3 inflammasome can be activated by the imbalance of the internal environment and a large number of metabolites. The biochemical function of NLRP3 inflammasome is to activate cysteine-requiring aspartate proteinase-1 (caspase-1), which converts pro-IL-1β and pro-IL-18 into their active forms, namely, IL-1β and IL-18, which are then released into the extracellular space. The well-established, classic role of NLRP3 inflammasome has been implicated in many disorders. In this review, we discuss the current understanding of NLRP3 inflammasome and its critical role in gynecological disorders and obstetrical complications.

Quantifying CD138+ cells in the endometrium to assess chronic endometritis in women at risk of recurrent pregnancy loss: A prospective cohort study and rapid review

OBJECTIVE

To determine the value of uterine CD138+ cells, as a marker of chronic endometritis, in predicting subsequent reproductive outcome in women with history of recurrent pregnancy loss.

DESIGN

A prospective longitudinal study.

SETTING

Tertiary specialized clinic.

PATIENTS

Women with history of recurrent pregnancy loss or implantation failure over a 12-months follow-up period.

INTERVENTION

We quantified the CD138+ cells/high powered field (hpf) using immunohistochemistry and image analysis of endometrial biopsies obtained during the secretory stage post ovulation.

MAIN OUTCOME MEASURES

Live birth and subsequent pregnancy loss. We calculated the receiver operator curve for predicting subsequent pregnancy loss and reported using relative risk (RR) and 95% confidence intervals (CI).

RESULTS

We enrolled 344 women of whom 88 became pregnant (88/344, 25.5%). Half of them had a subsequent live birth (47/88, 53%) and the rest lost their pregnancy (41/88, 46%). The median CD138+ score was significantly lower in the live birth group (P < 0.005) and women with a CD138+ score ≥ 16/hpf had a higher risk of subsequent miscarriage (RR 10.0, 95% CI 2.78-36.02). CD138+ cells count showed a good prediction for subsequent pregnancy loss in high-risk women with an area under the curve of 0.75 (95% CI 0.59-0.82, P = 0.01). A cut-off value of 4-6 cells/hpf offered the best predictive accuracy with higher scores predicting worse reproductive outcome. Our findings are limited by the small event rate and the sample size of our cohort.

CONCLUSION

Quantifying CD138+ cells by immunohistochemistry in women with a history of recurrent pregnancy loss is helpful to diagnose chronic endometritis and predict subsequent reproductive outcome.

Differentially expressed circulating microRNAs associated with idiopathic recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a major pregnancy complication which reportedly affects 2-3% of all pregnancies. Currently, RPL lacks an effective therapy and a reliable diagnostic and prognostic biomarker. Circulating microRNAs were recently described as potential biomarkers of pregnancy-associated complications. The aim of this study was to determine microRNA expression patterns in the plasma of RPL patients as potential early biomarker of RPL. Study subjects comprised 20 women with early RPL (miscarriage at 8-12 weeks of gestation), and 20 age- and gestation-matched multiparous control women. Circulating microRNAs were extracted from maternal plasma, and the differential microRNA expression were determined using customized pathway-focused miRNA profiler kit. Of the 10 differentially-expressed microRNAs identified, Hsa-let-7e, Hsa-miR-221-3p, Hsa-miR-16, Hsa-miR-519d, Hsa-miR-184, Hsa-miR-410 were upregulated, while Hsa-miR-21, Hsa-miR-125, Hsa-let-7a, Hsa-let-7d were downregulated in RPL cases as compared to control women. Of these, 5 novel microRNAs were reported for the first time to be associated with RPL. These comprised Hsa-let-7e, Hsa-miR-519d, Hsa-miR-410 which were upregulated, and Hsa-let-7a, Hsa-let-7d which were downregulated in RPL. While its association with RPL was reported earlier, this study is also the first to report on the upregulation of Hsa-miR-184 in circulating fluids in association with RPL. The study provides for understanding circulating microRNAs expression pattern in RPL which may be involved in its pathogenesis and demonstrates their potential role as noninvasive diagnostic and prognostic biomarkers for RPL.

Adoptive transfer of Tregs: A novel strategy for cell-based immunotherapy in spontaneous abortion: Lessons from experimental models

Since half of the genes are inherited from the paternal side, the maternal immune system has to tolerate the presence of foreign paternal antigens. Regulatory T cells facilitate the development and maintenance of peripheral tissue tolerance of the fetus during pregnancy. Reduction in regulatory T cells is associated with complications of pregnancy, including spontaneous abortion. Recent studies in mouse models have shown that the adoptive transfer of Tregs can prevent spontaneous abortion in mouse models through improving maternal tolerance. Thus, adoptive cell therapy using autologous Tregs could potentially be a novel therapeutic approach for cell-based immunotherapy in women with unexplained spontaneous abortion. Besides, strategies for activating and expanding antigen-specific Tregs ex vivo and in vivo based on pharmacological agents can pave the foundation for an approach incorporating immunotherapy and pharmacotherapy. This review aims to elaborate on the current understanding of the therapeutic potential of the adoptive transfer of Tregs in the treatment of spontaneous abortion disease.

Association between rs1049174 NKG2D gene polymorphism and idiopathic recurrent spontaneous abortion in Iranian women: a case-control study

Natural killer group 2, member D (NKG2D) is one of the best known activating receptors of NK cells, which recognises its ligand on altered or stressed cells and activates NK cells to kill them. In this study, the single nucleotide polymorphism of the NKG2D gene for rs1049174 mutation was compared in 140 women with recurrent spontaneous abortion (RSA) and 175 control women with at least one successful pregnancy and without any known pregnancy loss. The findings just revealed that GG genotype and G allele were significantly higher in the case group compared with the control group (p < .001). Our results regarding decreased risk of RSA in C allele (OR = 0.438; 95%CI = 0.310-0.619; p < .001), and GC genotype (OR = 0.492; 95%CI = 0.214-0.574; p < .001) compared with G allele and GG genotype respectively. This study demonstrated a significant association between NKG2D gene polymorphism (rs1049174 G/C) and the risk of RSA in Iranian women.Impact statementWhat is already known on this subject? According to previous investigations, maternal immune responses may affect the foetus, causing recurrent spontaneous abortion (RSA). The main cause of RSA has not yet been detected in nearly 50% of the cases.What do the results of this study add? The results showed that the frequency of G allele and C allele were significantly different in the case group and control group.What are the implications of these findings for clinical practice and/or further research? The results suggest a protective function of C allele because it significantly decreased the risk of RSA compared to G allele. It improves inhibition of NK cells and probably participates in maintaining pregnancy in fertile controls; whereas, G allele is related to a slight inhibition of NK cells, probably leading to increase effectiveness of NK activation and undesirable inflammation, which consequently causes foetal rejection.