Cytokines in relation to hCG are significantly altered in asymptomatic women with miscarriage - a pilot study

TNF-α-positive patients with recurrent pregnancy loss: The etiology and management

BACKGROUND

Elevated levels of tumor necrosis factor-alpha (TNF-α) have been associated with adverse pregnancy outcomes, specifically recurrent pregnancy loss (RPL). These elevated levels may be associated with the presence of autoantibodies. Although TNF-α inhibitors have shown promise in improving pregnancy rates, further research is needed to comprehend their impact and mechanisms in RPL patients.

OBJECTIVE

This study aims to investigate the association between elevated TNF-α levels and autoantibodies in RPL patients, as well as evaluate the effect of TNF-α inhibition on pregnancy outcomes.

METHODS

A total of 249 RPL patients were included in this study. Serum levels of TNF-α, autoantibodies, and complement were measured and monitored. Among these patients, 138 tested positive for TNF-α, while 111 tested negative. The medical records of these patients were retrospectively evaluated. Additionally, 102 patients with elevated TNF-α levels were treated with TNF-α inhibitors, and their pregnancy outcomes were assessed.

RESULTS

TNF-α-positive RPL patients had higher levels of complement C1q, anti-cardiolipin (ACL)-IgA, ACL-IgM ,ACL-IgG, thyroglobulin antibody, and Anti-phosphatidylserine/prothrombin IgM antibody, as well as a higher positive rate of antinuclear antibodies compared to TNF-α-negative patients (23.19% vs. 12.6%, P< 0.05). Conversely, complement C3 were lower in TNF-α-positive patients (t test, P< 0.05). The use of TNF-α inhibitors led to a reduction in the early abortion rate (13.7% vs. 44.4%, P< 0.001) and an improvement in term delivery rate (52.0% vs. 27.8%, P= 0.012). Furthermore, patients who used TNF-α inhibitors before 5 weeks of pregnancy had a lower early abortion rate (7.7% vs. 24.3%, P= 0.033) and a higher term delivery rate (69.2% vs. 48.6%, P= 0.033).

CONCLUSION

TNF-α plays a role in the occurrence and development of RPL, and its expression is closely associated with autoantibodies and complements. TNF-α inhibitors increase the term delivery rate in TNF-α-positive RPL patients, and their use before 5 weeks of pregnancy may more beneficial.

CCL2: An important cytokine in normal and pathological pregnancies: A review

C-C motif ligand 2 (CCL2), also known as monocytic chemotactic protein 1 (MCP-1), is an integral chemotactic factor which recruits macrophages for the immune response. Together with its receptors (e.g., CCR2, ACKR1, and ACKR2), they exert noticeable influences on various diseases of different systems. At the maternal-fetal interface, CCL2 is detected to be expressed in trophoblasts, decidual tissue, the myometrium, and others. Meanwhile, existing reports have determined a series of physiological regulators of CCL2, which functions in maintaining normal recruitment of immunocytes, tissue remodeling, and angiogenesis. However, abnormal levels of CCL2 have also been reported to be associated with adverse pregnancy outcomes such as spontaneous abortion, preeclampsia and preterm labor. In this review, we concentrate on CCL2 expression at the maternal-fetal interface, as well as its precise regulatory mechanisms and classic signaling pathways, to reveal the multidimensional aspects of CCL2 in pregnancy.

The effects of nutritional level and body condition score on cytokines in seminal plasma of beef bulls

Introduction

High quality semen is essential for reproductive efficiency. Nutrition and environmental factors impact the ejaculate components, like cytokines, that are essential for pregnancy establishment. We hypothesized that differing nutritional periods and body condition scores would affect seminal plasma cytokine concentrations of bulls.

Methods

Mature Angus bulls (n=11) were individually housed and randomly assigned to either over-fed (n=5) or restricted (n=6) treatment pathways. Bulls were fed different volumes of a single ration creating 8 individual treatment periods. Body weight and body condition scores were taken every 14 d to manage intake volumes. Ejaculates were collected every 84 d to determine seminal plasma cytokine profiles. A complete randomized design was used to evaluate seminal plasma cytokines after each nutritional treatment. Initial cytokine concentrations and volume of the ejaculate were included as covariates.

Results

All cytokines returned to initial concentrations following maintenance treatments at an ideal body condition score of 6. Nutritional treatments affected (P ≤ 0.05) IFN-γ, IL-8, MIP-1α, MIP-1β, TNF-α, IL-1β, and VEGF-A. However, TNF-α, IFN-γ, and MIP-1α had the greatest impact on cytokine profile.

Discussion

Nutritional levels and adiposity altered seminal plasma cytokine concentrations which could potentially impact the inflammatory balance of the uterus and the immune responses necessary for pregnancy establishment.

The Update Immune-Regulatory Role of Pro- and Anti-Inflammatory Cytokines in Recurrent Pregnancy Losses

Recurrent pregnancy losses (RPL) is a common reproductive disorder with various underlying etiologies. In recent years, rapid progress has been made in exploring the immunological mechanisms for RPL. A propensity toward Th2 over Th1 and regulatory T (Treg) over Th17 immune responses may be advantageous for reproductive success. In women with RPL and animals prone to abortion, an inordinate expression of cytokines associated with implantation and early embryo development is present in the endometrium or decidua secreted from immune and non-immune cells. Hence, an adverse cytokine milieu at the maternal-fetal interface assaults immunological tolerance, leading to fetal rejection. Similar to T cells, NK cells can be categorized based on the characteristics of cytokines they secrete. Decidual NK (dNK) cells of RPL patients exhibited an increased NK1/NK2 ratio (IFN-γ/IL-4 producing NK cell ratios), leading to pro-inflammatory cytokine milieu and increased NK cell cytotoxicity. Genetic polymorphism may be the underlying etiologies for Th1 and Th17 propensity since it alters cytokine production. In addition, various hormones participate in cytokine regulations, including progesterone and estrogen, controlling cytokine balance in favor of the Th2 type. Consequently, the intricate regulation of cytokines and hormones may prevent the RPL of immune etiologies. Local or systemic administration of cytokines or their antagonists might help maintain adequate cytokine milieu, favoring Th2 over Th1 response or Treg over Th17 immune response in women with RPL. Herein, we provided an updated comprehensive review regarding the immune-regulatory role of pro- and anti-inflammatory cytokines in RPL. Understanding the roles of cytokines involved in RPL might significantly advance the early diagnosis, monitoring, and treatment of RPL.

Independent value of serum β-human chorionic gonadotropin in predicting early pregnancy loss risks in IVF/ICSI cycles

Background

Early pregnancy loss (EPL) is the most prevalent complication, particularly in couples undergoing assisted reproductive technology treatment. The present study aimed to determine whether the serum β-human chorionic gonadotropin (β-hCG) level after 14 days of embryo transfer, either alone or in conjunction with other parameters in IVF/ICSI cycles, could be used to predict subsequent EPL.

Methods

This was a retrospective cohort study of all couples who received clinical pregnancy and underwent fresh IVF/ICSI cycles at a single large reproductive medical center between January 2013 and June 2020. The research involved a total of 6600 cycles. For risk variables, we conducted the least absolute shrinkage and selection operator (LASSO) analysis, and for risk scoring, we used logistic regression coefficients. To analyze relevant risk factors for EPL, univariate and multivariate logistic regression analyses were employed. Areas under the curve (AUC) were determined and compared between β-hCG and other factors using receiver operating characteristic (ROC) curves.

Results

β-hCG level was considerably lower in women who had EPL than in those who were ongoing pregnancy (564.03 ± 838.16 vs 1139.04 ± 1048.72 IU/L, p< 0.001). Univariable and multivariable logistic regression revealed that β-hCG levels were significantly correlated with the probability of EPL, independent of other risk factors. More importantly, the β-hCG level could independently predict the occurrence of EPL and was comparable to the model that combined other risk factors. The optimal serum β-hCG cut-off value for predicting EPL was 542.45 IU/L.

Conclusions

Our results suggest that the serum β-hCG level has a strong independent predictive value for EPL occurrence in fresh IVF/ICSI cycles.

Human Chorionic Gonadotropin and Early Embryogenesis: Review

Human chorionic gonadotropin (hCG) has four major isoforms: classical hCG, hyperglycosylated hCG, free β subunit, and sulphated hCG. Classical hCG is the first molecule synthesized by the embryo. Its RNA is transcribed as early as the eight-cell stage and the blastocyst produces the protein before its implantation. This review synthetizes everything currently known on this multi-effect hormone: hCG levels, angiogenetic activity, immunological actions, and effects on miscarriages and thyroid function.

Role of Transforming Growth Factor-β1 in Regulating Fetal-Maternal Immune Tolerance in Normal and Pathological Pregnancy

Transforming growth factor-β (TGF-β) is composed of three isoforms, TGF-β1, TGF-β2, and TGF-β3. TGF-β1 is a cytokine with multiple biological functions that has been studied extensively. It plays an important role in regulating the differentiation of immune cells and maintaining immune cell functions and immune homeostasis. Pregnancy is a carefully regulated process. Controlled invasion of trophoblasts, precise coordination of immune cells and cytokines, and crosstalk between trophoblasts and immune cells play vital roles in the establishment and maintenance of normal pregnancy. In this systematic review, we summarize the role of TGF-β1 in regulating fetal-maternal immune tolerance in healthy and pathological pregnancies. During healthy pregnancy, TGF-β1 induces the production of regulatory T cells (Tregs), maintains the immunosuppressive function of Tregs, mediates the balance of M1/M2 macrophages, and regulates the function of NK cells, thus participating in maintaining fetal-maternal immune tolerance. In addition, some studies have shown that TGF-β1 is dysregulated in patients with recurrent spontaneous abortion or preeclampsia. TGF-β1 may play a role in the occurrence and development of these diseases and may be a potential target for the treatment of these diseases.

Effect of Intralipid infusion on peripheral blood T cells and plasma cytokines in women undergoing assisted reproduction treatment

Objectives

Intravenous infusion of Intralipid is an adjunct therapy in assisted reproduction treatment (ART) when immune‐associated infertility is suspected. Here, we evaluated the effect of Intralipid infusion on regulatory T cells (Treg cells), effector T cells and plasma cytokines in peripheral blood of women undertaking IVF.

Methods

This prospective, observational pilot study assessed Intralipid infusion in 14 women exhibiting recurrent implantation failure, a clinical sign of immune‐associated infertility. Peripheral blood was collected immediately prior to and 7 days after intravenous administration of Intralipid. Plasma cytokines were measured by Luminex, and T‐cell subsets were analysed by flow cytometry.

Results

A small increase in conventional CD8⁺ T cells occurred after Intralipid infusion, but no change was seen in CD4⁺ Treg cells, or naïve, memory or effector memory T cells. Proliferation marker Ki67, transcription factors Tbet and RORγt, and markers of suppressive capacity CTLA4 and HLA‐DR were unchanged. Dimensionality‐reduction analysis using the tSNE algorithm confirmed no phenotype shift within Treg cells or other T cells. Intralipid infusion increased plasma CCL2, CCL3, CXCL8, GM‐CSF, G‐CSF, IL‐6, IL‐21, TNF and VEGF.

Conclusion

Intralipid infusion elicited elevated pro‐inflammatory cytokines, and a minor increase in CD8⁺ T cells, but no change in pro‐tolerogenic Treg cells. Notwithstanding the limitation of no placebo control, the results do not support Intralipid as a candidate intervention to attenuate the Treg cell response in women undergoing ART. Future placebo‐controlled studies are needed to confirm the potential efficacy and clinical significance of Intralipid in attenuating cytokine induction and circulating CD8⁺ T cells.

Pro- and Anti-Inflammatory Cytokines in the First Trimester-Comparison of Missed Miscarriage and Normal Pregnancy

The advantage in response of Th2 over Th1 is observed in normal pregnancy in peripheral blood. A disturbance of this balance can lead to symptoms of miscarriage and pregnancy loss. The aim of this study was to evaluate the pro- and anti-inflammatory cytokines in sera of women who were diagnosed with missed miscarriage in the first trimester and to compare this systemic immune response to the response in women with normal pregnancy. The study group consisted of 61 patients diagnosed with missed miscarriage. In total, 19 healthy women with uncomplicated first trimester created the control group. Cytokines were determined in the maternal serum by ELISA. The analysis included INF-γ, TNF-α, Il-1β, Il-4, Il-5, Il-6, Il-9, Il-10, Il-13 and TGF-β1. Th1 cytokine levels in the study group reached slightly higher values for INF-γ, Il-1β and slightly lower for IL-6 and TNF-α. In turn, Th2 cytokine levels in the study group were slightly higher (Il-9, Il-13), significantly higher (Il4, p = 0.015; Il-5, p = 0.0003) or showed no differences with the control group (Il-10). Slightly lower concentration involved only TGF-β1. Analysis of the correlation between levels of pro- and anti-inflammatory cytokines resulted in some discrepancies, without showing predominance of a specific immune response. The results did not confirm that women with missed miscarriage had an advantage in any type of immune response in comparison to women with normal pregnancy.

Interleukin-1 beta is significantly upregulated in the decidua of spontaneous and recurrent miscarriage placentas

BACKGROUND

Pregnancy is an extraordinarily complex immunological process. For successful pregnancy maintenance the maternal immune system must adapt to and tolerate the semi-allogenic fetus at the fetomaternal interface of the placenta. This balance is regulated by cytokines with a predominant T helper 2 (Th-2) system and a suppressed inflammatory T helper 1 (Th-1) response. This study investigates the role of the Th-1 pro-inflammatory cytokine Interleukin-1 beta (IL-1β) and its role in early pregnancy loss.

PATIENTS AND METHODS

In order to identify differences in IL- β levels a TaqMan® Human Cytokine Network Array, with placental tissue obtained from patients with healthy pregnancies (n = 15) and recurrent miscarriage (n = 15), was carried out. Protein expression of IL-1β in the decidua of healthy pregnancies (n = 15), spontaneous (n = 18) and recurrent miscarriages (n = 15), was investigated by immunohistochemistry. The identification of IL-1β expressing cells in the decidua was done with double-immunofluorescence.

RESULTS

Gene expression analysis identified a nearly 54-times higher expression of IL-1β in placental tissue of patients suffering from recurrent abortion. Immunohistochemistry confirmed a significant upregulation of IL-1β in the decidua of recurrent miscarriage specimens (p = 0.01) as well as in the decidua of women with spontaneous abortion (p = 0.001). Double-immunofluorescence identified decidual stoma cells as IL-1β expressing cells.

CONCLUSION

Significant upregulation of IL-1β may be associated with an imbalanced immune system and a procoagulant state that could be responsible for early pregnancy loss. These results provide new evidence of the complex interplay of IL-1β at the fetomaternal interface and its crucial role in miscarriage processes.

Pregnancy Zone Protein (PZP) is significantly upregulated in the decidua of recurrent and spontaneous miscarriage and negatively correlated to Glycodelin A (GdA)

BACKGROUND

Pregnancy Zone Protein (PZP) is an immunosuppressive protein that is expressed by the placenta and has also been identified in immune cells. When PZP and Glycodelin A (GdA) are combined, they act synergistically to inhibit Th-1 immune response. Little is known about its combined expression and role in normal and disturbed first trimester pregnancy.

PATIENTS AND METHODS

We investigated the expression of PZP and GdA in placental tissue obtained from spontaneous miscarriage (SM) (n = 19) and recurrent miscarriage (RM) (n = 17) at gestational weeks 6-13 by immunohistochemistry and on mRNA-level by either TaqMan PCR or in situ hybridization. Placental tissue from legal terminations of healthy pregnancies (n = 15) served as control group. Immunofluorescence double staining was used to analyse the combined expression of PZP and GdA in decidual tissue.

RESULTS

The protein level of PZP was significantly increased in decidual stroma of SM samples compared to the decidua of control specimens and also significantly upregulated in the decidual stroma cells in the RM group. Concerning GdA, the decidual stroma revealed a significantly decreased protein level in the group with spontaneous abortions than in the group with healthy pregnancies. There was also a significant downregulation of GdA in the decidual stroma of RM samples compared to the control group. We observed a significant negative correlation of PZP and GdA in decidual stromal tissue of recurrent abortion. We could confirm the staining results for PZP as well as for GdA on mRNA level. Both proteins are co-localized in decidual stroma as analysed by immunofluorescence double staining.

CONCLUSION

A balanced expression of GdA and its carrier protein PZP in the decidua seems crucial for a successful ongoing pregnancy. According to our data, these immunosuppressive proteins are co-localized in the decidual tissue and show a negative correlation only in patients suffering from recurrent abortion.

The role of the IL-1 system in pregnancy and the use of IL-1 system markers to identify women at risk for pregnancy complications†

The interleukin (IL)-1 system plays a major role in immune responses and inflammation. The IL-1 system components include IL-1α, IL-1β, IL-1 receptor type 1 and IL-1 receptor type 2 (decoy receptor), IL-1 receptor accessory protein, and IL-1 receptor antagonist (IL-1Ra). These components have been shown to play a role in pregnancy, specifically in embryo-maternal communication for implantation, placenta development, and protection against infections. As gestation advances, maternal tissues experience increasing fetal demand and physical stress and IL-1β is induced. Dependent on the levels of IL-1Ra, which regulates IL-1β activity, a pro-inflammatory response may or may not occur. If there is an inflammatory response, prostaglandins are synthesized that may lead to myometrial contractions and the initiation of labor. Many studies have examined the role of the IL-1 system in pregnancy by independently measuring plasma, cervical, and amniotic fluid IL-1β or IL-1Ra levels. Other studies have tested for polymorphisms in IL-1β and IL-1Ra genes in women experiencing pregnancy complications such as early pregnancy loss, in vitro fertilization failure, pre-eclampsia and preterm delivery. Data from those studies suggest a definite role for the IL-1 system in successful pregnancy outcomes. However, as anticipated, the results varied among different experimental models, ethnicities, and disease states. Here, we review the current literature and propose that measurement of IL-1Ra in relation to IL-1 may be useful in predicting the risk of poor pregnancy outcomes.

Human Chorionic Gonadotrophin: New Pleiotropic Functions for an "Old" Hormone During Pregnancy

Human chorionic gonadotrophin (hCG) is the first specific molecule synthesized by the embryo. hCG RNA is transcribed as early as the eight-cell stage, and the blastocyst produces the protein before its implantation. hCG in the uterine microenvironment binds with its cognate receptor, luteinizing hormone/choriogonadotropin receptor (LHCGR), on the endometrial surface. This binding stimulates leukemia inhibitory factor (LIF) production and inhibits interleukin-6 (IL-6) production by epithelial cells of the endometrium. These effects ensure essential help in the preparation of the endometrium for initial embryo implantation. hCG also effects angiogenic and immunomodulatory actions as reported in many articles by our laboratories and other ones. By stimulating angiogenesis and vasculogenesis, hCG provides the placenta with an adequate maternal blood supply and optimal embryo nutrition during the invasion of the uterine endometrium. The immunomodulatory properties of hCG are numerous and important for programming maternal immune tolerance toward the embryo. The reported effects of hCG on uterine NK, Treg, and B cells, three major cell populations for the maintenance of pregnancy, demonstrate the role of this embryonic signal as a crucial immune regulator in the course of pregnancy. Human embryo rejection for hCG-related immunological reasons has been studied in different ways, and a sufficient dose of hCG seems to be necessary to maintain maternal tolerance. Different teams have studied the addition of hCG in patients suffering from recurrent miscarriages or implantation failures. hCG could also have a beneficial or a negative impact on autoimmune diseases during pregnancy. In this review, we will discuss the immunological impacts of hCG during pregnancy and if this hormone might be used therapeutically.

IL-10 to TNFα ratios throughout early first trimester can discriminate healthy pregnancies from pregnancy losses

PROBLEM

Embryo implantation and placentation require a careful immunological balance. Cytokines such as IL-10 and TNFα have been implicated as markers of dysregulation, but have only been studied at a single time point or after a pregnancy loss. Our objective was to determine normative patterns of serum levels of IL-10 and TNFα and their ratio throughout the first trimester in healthy pregnancies and to determine if this pattern differs from pregnancy loss.

METHOD OF STUDY

Two prospective longitudinal cohorts of gravidae including in vitro fertilization (IVF) and naturally conceived pregnancies with serial blood draws. Cytokines were assayed using Simple Plex. In the IVF cohort, we monitored from the implantation day up to 6 weeks of gestation; whereas in the naturally conceived cohort, sample collection began at 4 weeks and throughout the whole first trimester.

RESULTS

IL-10 concentrations in normal pregnancies were significantly higher than in pregnancies ending in a loss starting at 6-8 weeks of gestation, while TNFα concentrations were significantly lower in normal than in pregnancies ending in a loss starting at 3-5 of gestation weeks. The IL-10 to TNFα ratio in normal pregnancies was significantly higher from 4 to 9 weeks compared to pregnancies that were lost (t test, P < .05). Changes were observed before any symptoms of miscarriage were present.

CONCLUSION

We provide evidences of differences in early immunomodulation in healthy pregnancies vs those destined to end in first-trimester loss. The ratio of IL-10 to TNFα rises significantly higher in viable pregnancies as early as 4.5 weeks compared to pregnancies loss.