Interleukin-1 system messenger ribonucleic acid and protein expression in human fallopian tube may be associated with ectopic pregnancy

Reduced innate lymphoid cells in the endometrium of women with endometriosis

PROBLEM

Innate lymphoid cells (ILCs), a recently discovered family of innate immune cells, are responsible for the early immune response, and control both innate and adapted immune system via cytokine secretion. The role of ILCs in endometriosis has not been investigated; therefore, here, we aimed to investigate how the proportion of ILCs changes in endometriosis.

METHOD OF STUDY

The percentage of each ILC group in CD45⁺ cells was examined in the peripheral blood, peritoneal fluid, endometrium, and ovarian endometrioma obtained from women with and without endometriosis (ERB-C-1216) using flow cytometry.

RESULTS

Specimens were obtained from 19 women with endometriosis and 15 without endometriosis. In the endometrium, patients with endometriosis had lower proportion of ILC2 and 3 compared to control specimens (ILC2: .02±.01% vs .07±.03%; P < .05, ILC3: .31±.14% vs 1.10±.93%; P < .05). There was no significant change in the peripheral blood or the peritoneal fluid between the two groups. Additionally, ovarian endometrioma increased the proportion of ILCs (ILC1: .92±1.12%, ILC2: .08±.08%, ILC3: .70±.39%) compared to the endometrium samples of patients with endometriosis each with P < .05. Immunohistochemistry of IL-1β and IL-23, which are ILC3-inducing factors, showed no significant change in the H-score of the epithelium of the two groups, but a significant increase was found in ovarian endometrioma.

CONCLUSION

The proportion of ILC2 and 3 was reduced in the endometrium of patients with endometriosis, and ILCs were increased in ovarian endometrioma. Our findings may indicate a new immunological approach to understand the pathophysiology of endometriosis.

The Role of Interleukin in Ectopic Pregnancy: A Systematic Review

BACKGROUND: Ectopic pregnancy (EP) is the implantation of an embryo outside the eutopic cavity with the most location of EP is in the fallopian tube (FT), known as tubal EP (TEP). The FT of TEP expresses higher levels of pro-inflammatory cytokines such as interleukin-1 (IL-1), IL-6, and IL-8. AIM: The study aimed to look systematically into the current literature and carefully analyze the results to explore the role of IL in EP. METHODS: Three independent reviewers conducted the literature search through some electronic databases searching for articles fulfilling inclusion and exclusion criteria. The lead author independently assessed the risk of bias of each of the 313 articles identified in database searching, 12 articles met the criteria for this review. CONCLUSION: IL-6 and IL-8 have diagnostic significance in predicting EP with the cutoff levels of IL-6 and IL-8 which were 26.48 and 40 pg/mL. Further, research is needed for the role of other interleukins in EP.

Upregulation of elafin expression in the fallopian tube of ectopic tubal pregnancies compared to the normal tubes

BACKGROUND

Ectopic pregnancy is one of the most important causes of maternal deaths and fallopian tubes are the location of 95% of ectopic pregnancies. Elafin is a natural antimicrobial molecule that plays an important role as an anti-inflammatory agent in mucosal surfaces and has been found in the female reproductive tract.

OBJECTIVES

The aim of this study was to investigate elafin expression, in the fallopian tube mucosa of ectopic pregnancies compared to the normal tubes using immunohistochemistry (IHC) techniques and quantitative reverse transcription (qRT)-PCR.

METHODS

In this case-control study, uterine tube samples were obtained from patients with an indication for surgical removal of the tubes. The case group (n = 20) consisted of patients who were undergoing salpingectomy due to an ectopic pregnancy, the control group (n = 20) included patients who had a salpingectomy and hysterectomy. Using qRT-PCR and IHC, the expression of elafin was investigated in both study groups.

RESULTS

Immunohistochemical expression of elafin in the epithelium and connective tissue was significantly increased in the implantation site of the patients in comparison with the control group (P < 0.001). The level of elafin mRNA increased in the mucous membrane of the fallopian tube from patients with the ectopic pregnancy compared to the normal mucosa (P < 0.001).

CONCLUSION

Increasing expression of elafin during an ectopic pregnancy may be a mechanism for enhancing innate immune response and be involved in related pathological conditions such as infection and ectopic implantation.

Simultaneous detection of two growth factors from human single-embryo culture medium by a bead-based digital microfluidic chip

The measurement of growth factors released in a culture medium is considered to be an attractive non-invasive approach, apart from the embryo morphology, to identify the condition of an embryo development after fertilization in vitro (IVF), but the available embryo culture medium in the current method is only a few microlitres. This small sample volume, also of small concentration, makes difficult the application of a conventional detection method, such as an enzyme-linked immunosorbent assay (ELISA). A reliable detection of the growth factor from each embryo culture medium of such a small concentration hence remains a challenge. Here for the first time we report the results of measurement of not just one, but two, growth factors, human IL-1β and human TNF-α, from an individual droplet of embryo culture medium with a bead-based digital microfluidic chip. The required sample volume for a single measurement is only 520 nL; the total duration of the on-chip process is less than 40 min. Using the culture media of human embryos with normal morphologic features, we found that the concentrations of TNF-α change little from day 3 to day 5-6, but the concentrations of IL-1β for some embryos might double from day 3 to day 5-6. For other embryos even with similar normal morphologic features, some growth factors, such as IL-1β, might exhibit different expressions during the culture period. Those growth factors could serve to distinguish the development conditions of each embryo, not merely from an observation of embryo morphology.

B cell activation factor (BAFF) induces inflammation in the human fallopian tube leading to tubal pregnancy

Background

Tubal pregnancy is recognized as one of the most common ectopic pregnancy types. Salpingitis may result in tubal pregnancy by causing fallopian tube occlusion and hydrosalpinx. B cell activation factor (BAFF) is a proinflammatory cytokine that helps regulate both innate and adaptive immune responses. Our previous study firstly showed that BAFF immunostaining appeared on the cellular membrane and in the cytoplasm of tubal epithelial cells, and both BAFF protein and mRNA in human inflamed fallopian tubes had higher expression levels than those in normal fallopian tubes. This study aimed to elucidate the association between the expression of BAFF gene and the inflammation in the human fallopian tube leading to tubal pregnancy.

Methods

We examined 70 patients undergoing salpingectomy for salpingitis (n = 35) and tubal pregnancy (n = 35). Twenty patients with benign uterine diseases undergoing complete hysterectomy and salpingectomy were recruited into control group. BAFF mRNA and protein in tissue samples were detected by qPCR and Western blotting methods. Furthermore, serum levels of BAFF, tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 were measured using ELISA kits.

Results

We found statistically significantly elevated expressions of BAFF mRNA or protein in whole tissue samples, and serum levels of BAFF, TNF-α and IL-6 in whole blood samples from patients with salpingitis and tubal pregnancy, in comparison to the control group.

Conclusion

Based on the results, high expression of BAFF gene might induce inflammation in the human fallopian tube, suggesting its possible role in the tubal pregnancy process.

Understanding the hidden relations between pro- and anti-inflammatory cytokine genes in bovine oviduct epithelium using a multilayer response surface method

An understanding gene-gene interaction helps users to design the next experiments efficiently and (if applicable) to make a better decision of drugs application based on the different biological conditions of the patients. This study aimed to identify changes in the hidden relationships between pro- and anti-inflammatory cytokine genes in the bovine oviduct epithelial cells (BOECs) under various experimental conditions using a multilayer response surface method. It was noted that under physiological conditions (BOECs with sperm or sex hormones, such as ovarian sex steroids and LH), the mRNA expressions of IL10, IL1B, TNFA, TLR4, and TNFA were associated with IL1B, TNFA, TLR4, IL4, and IL10, respectively. Under pathophysiological + physiological conditions (BOECs with lipopolysaccharide + hormones, alpha-1-acid glycoprotein + hormones, zearalenone + hormones, or urea + hormones), the relationship among genes was changed. For example, the expression of IL10 and TNFA was associated with (IL1B, TNFA, or IL4) and TLR4 expression, respectively. Furthermore, under physiological conditions, the co-expression of IL10 + TNFA, TLR4 + IL4, TNFA + IL4, TNFA + IL4, or IL10 + IL1B and under pathophysiological + physiological conditions, the co-expression of IL10 + IL4, IL4 + IL10, TNFA + IL10, TNFA + TLR4, or IL10 + IL1B were associated with IL1B, TNFA, TLR4, IL10, or IL4 expression, respectively. Collectively, the relationships between pro- and anti-inflammatory cytokine genes can be changed with respect to the presence/absence of toxins, sex hormones, sperm, and co-expression of other gene pairs in BOECs, suggesting that considerable cautions are needed in interpreting the results obtained from such narrowly focused in vitro studies.

Alteration of the immune cell profiles in the pathophysiology of tubal ectopic pregnancy

Tubal ectopic pregnancy (TEP) refers to implantation of conceptus in the fallopian tube. It makes up over 98% of ectopic pregnancy (EP), which is the leading cause of maternal morbidity and mortality in the first trimester of pregnancy. Immune cells at the maternal-fetal interface play important roles in the process of embryo implantation, stroma decidualization, and early placental development. Alterations in the composition, phenotype, and activity of the immune cells in the fallopian tubes contribute toward the onset of TEP. In this review, we compare the leukocytic proportions in decidua of normal pregnancy, and in decidua and fallopian tubes of TEP. The possible functions of these immune cells in the pathophysiology of TEP are also discussed.

IL-1β predicts IVF outcome: a prospective study

PURPOSE

Retrospective cohort studies have shown a relationship between maternal serum interleukin-1β (IL-1β) and interleukin-1 receptor antagonist (IL-1Ra) levels and in vitro fertilization (IVF) cycle outcome. The objective of this investigation was to explore the correlation between serum IL-1β and/or IL-1Ra levels obtained prospectively and IVF outcomes.

METHODS

Sera from 205 women were collected just prior to initiation of their IVF cycle, at the time of human chorionic gonadotropin administration, day 24 of IVF cycle, day 28, and day 35. Sera were analyzed for IL-1β and IL-1Ra using commercially available ELISA kits. Cycle outcomes were followed prospectively. Data were analyzed using Friedman analysis of variance by ranks and chi-square analysis.

RESULTS

Among women with a viable pregnancy, IL-1β serum levels increased over time for those that proceeded to deliver or had an ongoing pregnancy. There was no increase in serum levels for those with subsequent pregnancy loss. Of the women that had an embryo transfer, detectable IL-1β levels at the start of the cycle were associated with successful IVF outcome (p = 0.027). Of women with a positive pregnancy test, undetectable IL-1β at the start of the cycle were associated with subsequent pregnancy loss (p = 0.046). For all IL1-Ra serum analysis, there were no significant results.

CONCLUSIONS

The increasing levels of IL-1β over time are consistent with the known role of the IL-1 cytokine family in implantation and pregnancy. Additionally, we confirm in a prospective investigation the positive relationship between detectable serum IL-1β at the start of IVF cycle and outcome.

Immunoreactivities of IL-1β and IL-1R in oviduct of Chinese brown frog (Rana dybowskii) during pre-hibernation and the breeding period

The Chinese brown frog (Rana dybowskii) has one special physiological phenomenon, which is that its oviduct goes through expansion prior to hibernation instead of during the breeding period. In this study, we investigated the localization and expression level of interleukin-1 (IL-1β) and its functional membrane receptor type I (IL1R1) proteins in the oviduct of R. dybowskii during pre-hibernation and the breeding period. There were significant differences in both oviductal weight and pipe diameter, with values markedly higher in pre-hibernation than in the breeding period. Histologically, epithelium cells, glandular cells and tubule lumen were identified in the oviduct during pre-hibernation and the breeding period, while sizes of both cell types are larger in the pre-hibernation than those of the breeding period. IL-1β was immunolocalized in the cytoplasm of epithelial and glandular cells in both periods, whereas IL-1R1 was observed in the membrane of epithelial and glandular cells in the breeding period, whereas only in epithelial cells during pre-hibernation. Consistently, the protein levels of IL-1β and IL-1R1 were higher in pre-hibernation as compared to the breeding period. These results suggested that IL-1β may play an important autocrine or paracrine role in oviductal cell proliferation and differentiation of R. dybowskii.

Soluble ligands and their receptors in human embryo development and implantation

Extensive evidence suggests that soluble ligands and their receptors mediate human preimplantation embryo development and implantation. Progress in this complex area has been ongoing since the 1980s, with an ever-increasing list of candidates. This article specifically reviews evidence of soluble ligands and their receptors in the human preimplantation stage embryo and female reproductive tract. The focus will be on candidates produced by the human preimplantation embryo and those eliciting developmental responses in vitro, as well as endometrial factors related to implantation and receptivity. Pathways to clinical translation, including innovative diagnostics and other technologies, are also highlighted, drawing from this collective evidence toward facilitating joint improvements in embryo quality and endometrial receptivity. This strategy could not only benefit clinical outcomes in reproductive medicine but also provide broader insights into the peri-implantation period of human development to improve fetal and neonatal health.

From mice to women and back again: causalities and clues for Chlamydia-induced tubal ectopic pregnancy

OBJECTIVE

To provide an overview of knockout mouse models that have pathological tubal phenotypes after Chlamydia muridarum infection, discuss factors and pathological processes that contribute to inflammation, summarize data on tubal transport and progression of tubal implantation from studies in humans and animal models, and highlight research questions in the field.

DESIGN

A search of the relevant literature using PubMed and other online tools.

SETTING

University-based preclinical and clinical research laboratories.

PATIENT(S)

Women with tubal ectopic pregnancy after Chlamydia trachomatis infection.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Critical review of the literature.

RESULT(S)

Chlamydia trachomatis infection poses a major threat to human reproduction. Biological and epidemiological evidence suggests that progression of Chlamydia infection causes intense and persistent inflammation, injury, and scarring in the fallopian tube, leading to a substantially increased risk of ectopic pregnancy and infertility. The main targets of Chlamydia infection are epithelial cells lining the mucosal surface, which play a central role in host immune responses and pathophysiology. Tubal phenotypes at the cellular level in mutant mice appear to reflect alterations in the balance between inflammatory mediator and factor deficiency. While studies in mice infected with Chlamydia muridarum have provided insight into potential inflammatory mediators linked to fallopian tube pathology, it is unclear how inflammation induced by Chlamydia infection prevents or retards normal tubal transport and causes embryo implantation in the fallopian tube.

CONCLUSION(S)

Given the similarities in the tubal physiology of humans and rodents, knockout mouse models can be used to study certain aspects of tubal functions, such as gamete transport and early embryo implantation. Elucidation of the exact molecular mechanisms of immune and inflammatory responses caused by Chlamydia infection in human fallopian tubal cells in vitro and understanding how Chlamydia infection affects tubal transport and implantation in animal studies in vivo may explain how Chlamydia trachomatis infection drives inflammation and develops the tubal pathology in women with tubal ectopic pregnancy.

Detection of IL-1β in culture media supernatants of pre-implantation human embryos; its relation with embryo grades and development

In this study, we aimed to determine whether human embryos secrete interleukin-1β (IL-1β) into culture media and its correlation with embryo grade and development. Culture media supernatants of 100 embryos obtained from 39 cycles of 38 patients and cultivated individually were collected 2 and 3 days after intracytoplasmic sperm injection (ICSI). IL-1β concentrations of samples were determined with ELISA and compared with embryo grades and blastomere numbers. Embryo grades and the amount of IL-1β they secreted were found not to be correlated (p:0.559). Numbers of blastomeres each embryo had at 2nd and 3rd days were found to be correlated with IL-1β secreted (p:0.00 and p:0.00, respectively). Mean amount of IL-1β secreted by the embryos from ejaculated sperm cycles were found to be significantly higher than that of embryos from TESE cycles (p:0.016). Patient age and etiology of infertility were not correlated with the amount of IL-1β secreted and embryo grade. In conclusion, preimplantation human embryos secrete IL-1β in their media in amounts correlated with their blastomere numbers.

Interleukin-1 system in the human fallopian tube-No spatial but a temporal regulation of mRNA and protein expression

The human fallopian tube provides the environment for the first 5 days of embryonic development in vivo. The IL-1 system is involved in human embryo implantation. This study aimed to investigate IL-1beta, IL-1ra and IL-1R tI expression within the length of the human fallopian tube on mRNA- and protein-level in samples from proliferative versus secretory phase, postmenopause (PMP) samples and samples from intra- (IUP) and extrauterine pregnancies (EUP) to examine possible spatial and hormonal induced changes (fimbrial, ampullary and isthmic tube segments). On mRNA-level, IL-1beta was expressed in all samples except in PMP. IL-1R tI could be detected in all samples whereas IL-1ra was only expressed in secretory phase and the IUP sample. Immunohistochemically we could detect IL-1beta and IL-1R t1 protein in all proliferative and secretory phase samples with maximum intensity in secretory phase samples whereas IL-1ra was expressed in secretory phase samples only. Overall no spatial but temporal differences possibly due to hormonal changes could be observed suggesting a precise regulation of the IL-1 system, especially for IL-1ra and moreover a stable molecular architecture within the full length of the fallopian tube.

Eutopic endometrial interleukin-18 system mRNA and protein expression at the level of endometrial-myometrial interface in adenomyosis patients

OBJECTIVE

To investigate the eutopic endometrial interleukin-18 (IL-18) system including interleukin-18 (IL-18), IL-18 receptor (IL-18R), and IL-18 binding protein (IL-18BP), mRNA, and protein expression in patients with adenomyosis.

DESIGN

A clinical and molecular study.

SETTING

Clinical and academic research setting in a university medical center.

PATIENT(S)

Twenty-eight samples of human eutopic endometria were obtained from surgical specimens of normal cycling women undergoing hysterectomy for uterine adenomyosis (n = 19); the control group (n = 9) was women undergoing hysterectomy for benign reason including uterine fibroids.

INTERVENTION(S)

Quantitative competitive polymerase chain reaction (QC PCR) and immunohistochemistry studies were performed.

MAIN OUTCOME MEASUREMENT(S)

The differences of the IL-18 system mRNA and the ratio of IL-18BP to IL-18 in the eutopic endometrium of uterine adenomyosis and control group were analyzed.

RESULT(S)

IL-18 system mRNA and protein expression was demonstrated in the eutopic endometrium of both adenomyosis and control women. Quantitative competitive PCR demonstrated that endometrial IL-18R mRNA and the ratio of IL-18BP to IL-18 were significantly increased in adenomyosis patients in comparison to the control group. Pearson's correlation showed a significant correlation between IL-18 and IL-18R in the eutopic endometrium of women with uterine adenomyosis, but not the control group.

CONCLUSION(S)

The expression of the eutopic endometrial IL-18 system and the ratio of antagonist to agonist at the level of the endometrial-myometrial interface (EMI) may possibly be responsible for the pathologic process of adenomyosis.

Interleukin-1 in reproductive strategies

Evolutionary studies on different classes of vertebrates could help clarify the role of cytokines in acceptance of the embryo by the maternal tissues. This review focuses on the cytokine interleukin-1 (IL-1) and reports on its presence in the female reproductive tract of species with different reproductive strategies, that is, viviparity, oviparity, and ovuliparity. Unlike oviparity and viviparity, ovuliparity does not involve any contact between paternal-derived fetal antigens and maternal tissues, because eggs are released unfertilized in the external environment. Therefore, we consider ovuliparity a natural negative control for mechanisms of materno-fetal immunotolerance. The goal of this review is to discuss the role of the IL-1 system in the acquisition of the ability to retain the embryo in the female genital tract during the transition from ovuliparity to viviparity.

Interleukin 1 in Oviductal Tissues of Viviparous, Oviparous, and Ovuliparous Species of Amphibians1

In previous reports, we have shown that interleukin 1 (IL1), a cytokine associated with implantation in mice, is also expressed in reproductive tissues of viviparous squamate reptiles and cartilaginous fishes. In the present study, we investigated the expression of IL1B and its functional membrane receptor type I (IL1R1) in amphibians, a class of vertebrates that is characterized by different reproductive modes, including internal and external fertilization. In particular, we investigated the oviductal tissues of the aplacental viviparous Salamandra lanzai, the oviparous Triturus carnifex, and the ovuliparous Bufo bufo. In immunohistochemistry with anti-human IL1B and IL1R1 polyclonal antibodies we found that in S. lanzai, most cells in the uterine mucosa were immunoreactive for IL1B and IL1R1. In T. carnifex, IL1B and IL1R1 were present in ciliated luminal cells, and there was evidence of IL1B in glandular cells. In B. bufo, the expression of IL1B and IL1R1 was limited to the apical cytoplasm of the ciliated oviductal cells. Western blot analysis showed that a putative mature form of IL1B, similar to that seen in mammals, was present in the oviductal tissues of S. lanzai, whereas different forms, which probably correspond to an inactive pro-IL1B protein, were found in T. carnifex and B. bufo. A band that corresponded to the predicted 80-kDa human IL1R1 was found in S. lanzai and T. carnifex. Although the present study shows that IL1B and IL1R1 expression occurs in all reproductive modes, the differential expression patterns noted between ovuliparity and oviparity and viviparity may reflect the different roles of IL1 in the various reproductive modes.

Interleukin-18 system messenger RNA and protein expression in human endometrium during the menstrual cycle

OBJECTIVE

To investigate the IL-18 system, including IL-18, IL-18 receptor (IL-18R), IL-18 binding protein (IL-18BP), and IL-18 precursor (proIL-18), mRNA and protein expression in human endometrium during the menstrual cycle.

DESIGN

Controlled study.

SETTING

Clinical and academic research setting in a university medical center.

PATIENT(S)

Human endometrium was obtained from surgical specimens of normal cycling women undergoing hysterectomy for benign reasons.

INTERVENTION(S)

A total of 24 human endometrium samples were obtained at proliferative and secretory phase from surgical specimens of normal cycling women undergoing hysterectomy. Quantitative competitive polymerase chain reaction (QC PCR) and immunohistochemistry were performed.

MAIN OUTCOME MEASURE(S)

The differences of IL-18 system mRNA and the ratio of antagonist to agonist in both proliferative and secretory phases of endometrium were analyzed.

RESULT(S)

Our results showed a complete IL-18 system, including mRNA expression and protein production in both proliferative and secretory phases of the endometrium. The QC PCR demonstrated that both IL-18 and IL-18R decreased and IL-18BP increased mRNA expression in human endometrium in secretory phase compared with proliferative phase. A positive correlation of IL-18 and IL-18R in human endometrium was demonstrated in proliferative phase but not in secretory phase. In addition, there is a significantly higher ratio of IL-18BP to IL-18 mRNA levels in secretory endometrium compared with proliferative phase endometrium (P<.05).

CONCLUSION(S)

The expression and ratio of IL-18 antagonist to agonist may be responsible for embryo implantation.