Localization of tumour necrosis factor production in cells at the materno/fetal interface in human pregnancy

Does tumour necrosis factor alpha-induced cyclooxygenase-2 expression lead to spontaneous abortion in Chlamydia trachomatis-infected women

Cytokines might be involved in spontaneous abortion by triggering inflammatory mediators (Cyclooxygenases (Cox)) leading to spontaneous abortion in Chlamydia trachomatis (Ct)-infected women. Study aimed to quantitate the expression of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-8) and Cox-2 in endometrial curettage tissue (ECT) of Spontaneous Aborters (SA). SA (n = 135) and 120 age-matched controls were enrolled from SJH, New Delhi, India. PCR was performed for detection of Ct MOMP gene (537 bp) in ECT. mRNA expression of pro-inflammatory cytokines and Cox-2 was assessed by real-time qPCR. Data was statistically evaluated. 14.8% SA were diagnosed as Ct-positive. Elevated expression of TNF-α, IFN-γ, IL-8 and Cox-2 was observed in Ct-infected SA. Ct-positive recurrent aborters showed significantly higher cytokine expression. Significant positive correlation was found between expression of Cox-2 and TNF-α in infected SA. Data suggested an increased expression of Th-1 cytokines, particularly TNF-α that induced Cox-2 expression in ECT, leading to spontaneous abortion in Ct-infected pregnant women.

Coordinated expression of TNFα- and VEGF-mediated signaling components by placental macrophages in early and late pregnancy

INTRODUCTION

Mononuclear phagocytes are thought to significantly contribute to cytokine regulation at the maternal-foetal interface, but the role of placental macrophages has been poorly investigated. TNFα and VEGF were demonstrated to have regulatory effects on basic structures of the placenta, particularly the trophoblast and blood vessels. The aims of this study were to determine the expression of TNFα, VEGF and related receptors in placental macrophages, and how does the participation of placental macrophages alter with gestational age in TNFα- and VEGF-mediated signaling.

METHODS

Macrophages were isolated from placental villous tissue from normal pregnancies at either 9-12 or 38-40 weeks gestation. Cell surface receptors (TNFR1, TNFR2, VEGFR1, and VEGFR2) and intracellular TNFα and VEGF were quantified by flow cytometry after antibody staining. Basal and stimulated secretion of both cytokines and soluble TNF receptors was quantified by cytometric bead arrays. Secreted VEGFR1 was measured by ELISA.

RESULTS

The expression of TNFR1 and VEGFR1 was remarkably variable and did not change from first to third trimester. There was minimal basal TNFα production in the placental macrophages, but nearly all cells in the population produced VEGF. TNFα and VEGF secretion increased with gestational age accompanied by decreased secretion of the antagonists sTNFR1 and sVEGFR. Macrophages isolated from early term placentas were less effective in responding to bacterial endotoxin. Lipopolysaccharide induced increases in the secretion of TNFα, TNFR1, TNFR2, and VEGFR1 but did not affect the production of VEGF. In late pregnancy, a significant correlation was observed between TNFR1 and VEGFR1.

DISCUSSION

The progression of pregnancy is accompanied by the concerted increase in TNFα and VEGF secretion and decrease in the production of their soluble receptors, but the expression of cell surface receptors does not depend on gestational age. The observed patterns of basal and stimulated expression of TNFα and VEGF may reflect the dual immune and morphogenetic roles of placental macrophages in gestation. Compatible patterns of TNFR1 and VEGFR1 expression suggest common regulatory pathways for these receptors.

An M1-like Macrophage Polarization in Decidual Tissue during Spontaneous Preterm Labor That Is Attenuated by Rosiglitazone Treatment

Decidual macrophages are implicated in the local inflammatory response that accompanies spontaneous preterm labor/birth; however, their role is poorly understood. We hypothesized that decidual macrophages undergo a proinflammatory (M1) polarization during spontaneous preterm labor and that PPARγ activation via rosiglitazone (RSG) would attenuate the macrophage-mediated inflammatory response, preventing preterm birth. In this study, we show that: 1) decidual macrophages undergo an M1-like polarization during spontaneous term and preterm labor; 2) anti-inflammatory (M2)-like macrophages are more abundant than M1-like macrophages in decidual tissue; 3) decidual M2-like macrophages are reduced in preterm pregnancies compared with term pregnancies, regardless of the presence of labor; 4) decidual macrophages express high levels of TNF and IL-12 but low levels of peroxisome proliferator-activated receptor γ (PPARγ) during spontaneous preterm labor; 5) decidual macrophages from women who underwent spontaneous preterm labor display plasticity by M1↔M2 polarization in vitro; 6) incubation with RSG reduces the expression of TNF and IL-12 in decidual macrophages from women who underwent spontaneous preterm labor; and 7) treatment with RSG reduces the rate of LPS-induced preterm birth and improves neonatal outcomes by reducing the systemic proinflammatory response and downregulating mRNA and protein expression of NF-κB, TNF, and IL-10 in decidual and myometrial macrophages in C57BL/6J mice. In summary, we demonstrated that decidual M1-like macrophages are associated with spontaneous preterm labor and that PPARγ activation via RSG can attenuate the macrophage-mediated proinflammatory response, preventing preterm birth and improving neonatal outcomes. These findings suggest that the PPARγ pathway is a new molecular target for future preventative strategies for spontaneous preterm labor/birth.

Acute chorioamnionitis and funisitis: definition, pathologic features, and clinical significance

Acute inflammatory lesions of the placenta consist of diffuse infiltration of neutrophils at different sites in the organ. These lesions include acute chorioamnionitis, funisitis, and chorionic vasculitis and represent a host response (maternal or fetal) to a chemotactic gradient in the amniotic cavity. While acute chorioamnionitis is evidence of a maternal host response, funisitis and chorionic vasculitis represent fetal inflammatory responses. Intraamniotic infection generally has been considered to be the cause of acute chorioamnionitis and funisitis; however, recent evidence indicates that "sterile" intraamniotic inflammation, which occurs in the absence of demonstrable microorganisms induced by "danger signals," is frequently associated with these lesions. In the context of intraamniotic infection, chemokines (such as interleukin-8 and granulocyte chemotactic protein) establish a gradient that favors the migration of neutrophils from the maternal or fetal circulation into the chorioamniotic membranes or umbilical cord, respectively. Danger signals that are released during the course of cellular stress or cell death can also induce the release of neutrophil chemokines. The prevalence of chorioamnionitis is a function of gestational age at birth, and present in 3-5% of term placentas and in 94% of placentas delivered at 21-24 weeks of gestation. The frequency is higher in patients with spontaneous labor, preterm labor, clinical chorioamnionitis (preterm or term), or ruptured membranes. Funisitis and chorionic vasculitis are the hallmarks of the fetal inflammatory response syndrome, a condition characterized by an elevation in the fetal plasma concentration of interleukin-6, and associated with the impending onset of preterm labor, a higher rate of neonatal morbidity (after adjustment for gestational age), and multiorgan fetal involvement. This syndrome is the counterpart of the systemic inflammatory response syndrome in adults: a risk factor for short- and long-term complications (ie, sterile inflammation in fetuses, neonatal sepsis, bronchopulmonary dysplasia, periventricular leukomalacia, and cerebral palsy). This article reviews the definition, pathogenesis, grading and staging, and clinical significance of the most common lesions in placental disease. Illustrations of the lesions and diagrams of the mechanisms of disease are provided.

Interferon-γ differentially modulates the impact of tumor necrosis factor-α on human endometrial stromal cells

The pro-inflammatory T helper (Th)-1 cytokines, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), are immunological factors relevant at the feto-maternal interface and involved in the pathophysiology of implantation disorders. The synergistic action of the two cytokines has been described with regard to apoptotic cell death and inflammatory responses in different cell types, but little is known regarding the human endometrium. Therefore, we examined the interaction of TNF-α and IFN-γ in human endometrial stromal cells (ESCs). ESCs were isolated from specimens obtained during hysterectomy and decidualized in vitro. Cells were incubated with TNF-α, IFN-γ or signaling-inhibitor. Insulin-like growth factor binding protein (IGFBP)-1, prolactin (PRL), leukemia inhibitory factor (LIF), interleukin (IL)-6, IL-8, regulated on activation normal T-cell expressed and secreted protein (RANTES) and monocyte chemotactic protein (MCP)-1 were measured using ELISA and real-time RT-PCR. Nuclear factor of transcription (NF)-κB and its inhibitor (IκBα) were analyzed by in-cell western assay and transcription factor assay. TNF-α inhibited and IFN-γ did not affect the decidualization of ESCs. In contrast, IFN-gamma differentially modulated the stimulating effect of TNF-alpha on cytokines by enhancing IL-6, RANTES and MCP-1 and attenuating LIF mRNA expression. These effects were time- and dose-dependent. IFN-γ had no impact on the initial activation of NF-κB signaling. Histone-deacetylase activity was involved in the modulating effect of IFN-γ on RANTES secretion. These observations showed a distinct pattern of interaction of the Th-1 cytokines, TNF-α and IFN-γ in the human endometrium, which could play an important role in the pathophysiology of implantation disorders.

Heparin modulates chemokines in human endometrial stromal cells by interaction with tumor necrosis factor α and thrombin

OBJECTIVE

To study the impact of heparins on chemokines in decidualized human endometrial stromal cells (ESCs) in vitro.

DESIGN

In vitro experiment.

SETTING

Research laboratory.

PATIENT(S)

Premenopausal women undergoing hysterectomy for benign reasons.

INTERVENTION(S)

ESCs were isolated from hysterectomy specimens, decidualized in vitro and incubated with unfractionated heparin and low-molecular-weight heparins (LMWHs) as well as tumor necrosis factor (TNF) α or thrombin with or without heparins.

MAIN OUTCOME MEASURE(S)

Chemokines CXCL1, CXCL5, CXCL8, CCL2, and CCL5 were measured with the use of ELISA, and CXCL5, CXCL8, CCL2, and CCL5 were detected with the use of real-time reverse-transcription polymerase chain reaction. Cell viability was determined with the use of a fluorometric assay.

RESULT(S)

TNF-α and thrombin stimulated distinct patterns of chemokines in ESCs. Unfractionated heparin and LMWHs attenuated the TNF-α-mediated induction of CXCL8 and enhanced CXCL5, CCL2, and CCL5. The stimulating effect of thrombin on CXCL8 could be inhibited by heparin, whereas heparin had no impact on thrombin-induced CXCL1 and CCL2. Nuclear factor of transcription κB signaling mediated the effects of TNF-α. The effects of thrombin were mediated via extracellular signal-regulated protein kinases 1/2.

CONCLUSION(S)

Heparins have modulating effects on TNF-α- and thrombin-induced endometrial chemokines, which might have implications in the regulation of endometrial receptivity and early implantation.

Decidual cytokines and pregnancy complications: focus on spontaneous miscarriage

The establishment of pregnancy requires the co-ordinated implantation of the embryo into the receptive decidua, placentation, trophoblast invasion of the maternal decidua and myometrium in addition to remodelling of the uterine spiral arteries. Failure of any of these steps can lead to a range of pregnancy complications, including miscarriage, pre-eclampsia, fetal growth restriction, placenta accreta and pre-term birth. Cytokines are small multifunctional proteins often derived from leucocytes and have primarily been described through their immunomodulatory actions. The maternal-fetal interface is considered to be immunosuppressed to allow development of the semi-allogeneic placental fetal unit. However, cytokine profiles of the decidua and different decidual cell types suggest that the in vivo situation might be more complex. Data suggest that decidual-derived cytokines not only play roles in immunosuppression, but also in other aspects of the establishment of pregnancy, including the regulation of trophoblast invasion and spiral artery remodelling. This review focuses on the potential role of decidua-derived cytokines in the aetiology of unexplained spontaneous miscarriage.

The possible role of extravillous trophoblast-derived exosomes on the uterine spiral arterial remodeling under both normal and pathological conditions

A tenet of contemporary obstetrics is that events that compromise placentation increase the risk of complications of pregnancy and contribute to poor pregnancy outcome. In particular, conditions that affect the invasion of placental cells and remodeling of uterine spiral arteries compromise placental function and the subsequent development of the fetus. Extravillous trophoblast cells (EVTs) proliferate and migrate from the cytotrophoblast in the anchoring villi of the placenta and invade the maternal decidua and myometrium. These cells are localised with uterine uterine spiral arteries and are thought to induce vascular remodeling. A newly identified pathway by which EVTs may regulate vascular remodeling within the uterus is via the release of exosomes. Trophoblast cells release exosomes that mediate aspects of cell-to-cell communication. The aim of this brief commentary is to review the putative role of exosomes released from extravillous trophoblast cells in uterine spiral artery remodeling and, in particular, their role in the aetiology of preeclampsia. Placental exosomes may engage in local cell-to-cell communication between the cell constituents of the placenta and contiguous maternal tissues and/or distal interactions, involving the release of placental exosomes into biological fluids and their transport to a remote site of action.

LPS-challenged TNFα production, prostaglandin secretion, and TNFα/TNFRs expression in the endometrium of domestic cats in estrus or diestrus, and in cats with pyometra or receiving medroxyprogesterone acetate

Progesterone (P4) derivatives which are commonly used to block the cyclicity of domestic cats disturb the endocrine balance in the endometrium. The aims of this study were (i) to examine whether lipopolysaccharide (LPS) is responsible for enhancement of tumor necrosis factor-α (TNFα) secretion by the feline endometrial epithelial and stromal cells in vitro, (ii) to know whether immunolocalization of TNFα/TNFR1 and TNFR2 differs in cats at estrus or diestrus, receiving medroxyprogesterone acetate and suffering from pyometra, and (iii) to determine if TNFα-challenged prostaglandin secretion is stopped by prostaglandin synthases inhibitors. A total of 37 domestic adult cats in estrus or diestrus, receiving octane medroxyprogesterone or having clinical symptoms of pyometra, were enrolled in this study. The results obtained showed a distinct increase in LPS-challenged TNFα secretion in endometrial epithelial, but not stromal cells. TNFα augmented PG secretion was blocked by phospholipase A2 (PLA2) and cyclooxygeanase-2 (COX-2), but not by mitogen-activated protein kinase (MAPK) inhibitor. TNFα/TNFR1 and 2 protein expressions were limited mostly to the surface and glandular epithelium. TNFα/TNFRs protein was upregulated in the inflammatory uterus and hence may be involved in development of pathologic changes in the endometrial glands in cats receiving exogenous P4 as a hormonal contraceptive.

Involvement of inflammation in normal pregnancy

To study the role of inflammation throughout normal pregnancy and postpartum, 37 women with normal pregnancies, including normal neonatal outcome, participated. Blood and urine samples were collected from each woman at least six times during pregnancy and postpartum. Plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) and urinary levels of a prostaglandin-F2α (PGF2α ) metabolite were measured. Median, 25th to 75th centile and average change per gestational week of IL-6, TNF-α and the PGF2α metabolite were measured. Levels of IL-6 increased significantly throughout pregnancy and remained high postpartum. No change in TNF-α could be seen. The PGF2α metabolite levels increased significantly throughout pregnancy and decreased postpartum. These results suggest that mild but significant inflammatory activity is involved in the development of normal pregnancy, which might have important physiological roles.

The expression of thioredoxin-1 in preterm delivery placenta

Preterm delivery (PTD) is the leading cause of infant mortality and morbidity. However, the mechanism at the molecular level is still unknown. Placental inflammatory response and oxidative stress are associated with PTD. Thioredoxin-1 (TRX-1) regulates oxidative stress, inflammation, and the activities of transcription factors.

OBJECTIVES

The objective was to detect in placental tissues the expressions of TRX-1 and the TRX-1-related molecules: tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), thioredoxin-1-binding protein-2 (TBP-2), hypoxia inducible transcription factor 1α (HIF-1α), and forkhead box protein O3A (FoxO3A).

METHODS

PTD was defined as gestation of <37 weeks and term delivery (TD) as ≥37 weeks. The expressions of TRX-1 and TRX-1-related molecules were examined in placental tissues by real-time polymerase chain rection and western blot.

RESULTS

The expressions of TRX-1, TNF-α, COX-2, HIF-1α, and FoxO3A in the placenta of PTD were significantly higher as compared with TD, but no difference was observed in TBP-2 expression.

DISCUSSION

These results indicate that TRX-1 may be adaptively induced by the effects of inflammation and oxidative stress, suggesting protective roles for TRX-1 against these effects in the placenta of PTD.

IL-10 reduces levels of apoptosis in Toxoplasma gondii-infected trophoblasts

Background

To analyze the effects of IL-10 on the HLA-G expression and the apoptosis of trophoblasts infected with Toxoplasma gondii.

Methods

T. gondii-infected or uninfected human trophoblasts and immortalized human placental BeWo cells were cultured with or without human IL-10. Uninfected and infected cells without IL-10 cells served as controls. HLA-G expression was measured by real-time PCR and flow cytometry, respectively. Cells apoptosis were analyzed by flow cytometry. Apoptosis associated moleculars were measured by real-time PCR and Western bolt.

Results

HLA-G expression was increased in the infected trophoblasts and BeWo cells compared to uninfected cells. Treatment of infected cells with IL-10 decreased HLA-G expression compared to infected cells while no change in treatment of uninfected cells compared with uninfected cells. Levels of apoptosis and apoptosis associated caspase-3 and caspase-8 decreased and c-FLIP levels increased in treated infected cells with IL-10 compared to infected cells and no difference in IL-10 treated uninfected cells compared to uninfected cells.

Conclusions

IL-10 regulates HLA-G expression in T. gondii-infected trophoblasts. IL-10 treatment of infected trophoblasts reduced levels of apoptosis. This may contribute to the improvement in pregnancy outcomes when women infected with T. gondii treated with IL-10.

Human cytomegalovirus-induces cytokine changes in the placenta with implications for adverse pregnancy outcomes

Human cytomegalovirus (CMV) infection of the developing fetus can result in adverse pregnancy outcomes including death in utero. Fetal injury results from direct viral cytopathic damage to the CMV-infected fetus, although evidence suggests CMV placental infection may indirectly cause injury to the fetus, possibly via immune dysregulation with placental dysfunction. This study investigated the effects of CMV infection on expression of the chemokine MCP-1 (CCL2) and cytokine TNF-α in placentae from naturally infected stillborn babies, and compared these changes with those found in placental villous explant histocultures acutely infected with CMV ex vivo. Tissue cytokine protein levels were assessed using quantitative immunohistochemistry. CMV-infected placentae from stillborn babies had significantly elevated MCP-1 and TNF-α levels compared with uninfected placentae (p = 0.001 and p = 0.007), which was not observed in placentae infected with other microorganisms (p = 0.62 and p = 0.71) (n = 7 per group). Modelling acute clinical infection using ex vivo placental explant histocultures showed infection with CMV laboratory strain AD169 (0.2 pfu/ml) caused significantly elevated expression of MCP-1 and TNF-α compared with uninfected explants (p = 0.0003 and p<0.0001) (n = 25 per group). Explant infection with wild-type Merlin at a tenfold lower multiplicity of infection (0.02 pfu/ml), caused a significant positive correlation between increased explant infection and upregulation of MCP-1 and TNF-α expression (p = 0.0001 and p = 0.017). Cytokine dysregulation has been associated with adverse outcomes of pregnancy, and can negatively affect placental development and function. These novel findings demonstrate CMV infection modulates the placental immune environment in vivo and in a multicellular ex vivo model, suggesting CMV-induced cytokine modulation as a potential initiator and/or exacerbator of placental and fetal injury.

Interleukin 10 and tumor necrosis factor-alpha in pregnancy: aspects of interest in clinical obstetrics

The purpose of this study was to review the literature regarding the action of the cytokines interleukin 10 (IL-10) and tumor necrosis factor-alpha (TNF-α) in pregnancy and to emphasize the factors that are of interest to clinical obstetrics. The literature highlights several actions of IL-10 and TNF-α during pregnancy. The actions of these cytokines seem to be antagonistic and dependent on the balance between them, which is orchestrated by the specific immunosuppressive action of IL-10. TNF-α has a characteristic inflammatory action, and it is an additional diabetogenic factor in pregnancy. The loss of the control of the production of these cytokines, with increase of TNF-α, is related to the risk for developing obstetric complications, particularly recurrent fetal loss, gestational diabetes mellitus, hypertensive syndromes, and fetal growth restriction. However, study results are controversial and are not clearly defined. These issues are attributed to the heterogeneity of the studies, particularly regarding their sample sizes and sources, the evaluation methods, and the multiplicity of factors and conditions that influence cytokine production. These questions are fundamental and should be addressed in future investigations to obtain more consistent results that can be applied to obstetric practice.

Tumor necrosis factor α induces a model of preeclampsia in pregnant baboons (Papio hamadryas)

Preeclampsia is a common disease of pregnancy characterised by maternal hypertension and proteinuria. Abnormal placentation in early pregnancy and abnormal cytokine and anti-angiogenic factor expression are thought to contribute to the clinical syndrome of endothelial dysfunction evident in the second half of gestation. The mechanisms underlying both the placental pathology and its translation to the maternal clinical syndrome are not fully understood. A model of preeclampsia manifest by clinically evident endothelial dysfunction (increased blood pressure and proteinuria) was induced by administration of low-dose TNF-α for 2weeks at mid-gestation in pregnant baboons (Papio hamadryas). Blood pressure was monitored continuously and remotely by intra-arterial radiotelemetry. Following TNF-α infusion, there was an increase in systolic and diastolic blood pressure and development of proteinuria in pregnant treated animals, but not in pregnant saline controls nor in non-pregnant TNF-α treated animals. The treated pregnant animals also developed elevated plasma soluble FMS-like tyrosine kinase-1 (sFLT-1) and increased placental mRNA expression of sFLT-1 and soluble endoglin (sEng). These results clearly demonstrate that the cytokine TNF-α can induce the clinical and biochemical features of human preeclampsia. The results identify a link between cytokines, placental dysfunction and endothelial dysfunction resulting in a loss of maternal blood pressure control.

Effect of tumour necrosis factor-α in combination with interferon-γ on first trimester extravillous trophoblast invasion

Successful pregnancy is dependent upon invasion of the uterine tissues by extravillous trophoblast cells (EVT). The mechanisms that control trophoblast invasion are unclear, but several cytokines and growth factors appear to be involved. We have previously demonstrated that IFN-γ inhibits EVT invasion via a mechanism partially dependent on an increase in EVT apoptosis and decreased secretion of matrix metalloproteinase (MMP)-2. In the current study we show that TNF-α, both alone and in combination with IFN-γ, inhibits EVT invasion via a mechanism associated with increased trophoblast apoptosis, decreased trophoblast proliferation and/or altered production of active proteases. TNF-α and its receptors, TNF-αRI and TNF-αRII, were immunolocalised in the placental bed. Uterine natural killer (uNK) cells, EVT and villous cytotrophoblast were shown to all produce TNF-α, and TNF-α receptors were primarily immunolocalised to EVT in the placental bed. TNF-α increased EVT apoptosis, decreased villous cytotrophoblast proliferation and increased expression of pro-MMP-9 (but not active MMP-9), urokinase plasminogen activator (uPA) and plasminogen activator inhibitor (PAI)-1 by EVT. The combination of TNF-α and IFN-γ inhibited EVT via a mechanism associated with increased EVT apoptosis, reduced proliferation, reduced pro-MMP-2 secretion and increased secretion of uPA. TNF-α is one of several decidua-derived factors with the capacity to inhibit EVT invasion. The mode of activity of TNF-α was modified by the presence of IFN-γ, suggesting that the local cytokine milieu may be critical in determining spatial and/or temporal changes in EVT invasion.

Inflammation and preeclampsia

No individual can claim credit for all the advances made during his lifetime. However, certain individuals have a far greater influence than others. Prof. Christopher Redman has had a huge role to play in increasing the understanding of the aetiology, pathology, progression and management of preeclampsia. The work he did personally, led in others and stimulated in colleagues, both friend and foe, has helped to progress preeclampsia from a disease that came from nowhere to one that is more understood and safely managed. In this paper, it is the work in immunology that will be concentrated on in a chronological way but this will be linked to other relevant research and clinical practice. The understanding that preeclampsia is a two-stage disease starting in the placenta and progressing systemically has led to greater understanding as well as more questions. The universal role of immunology first as an acceptor within the placental bed then as a disease driver in the systemic circulation emphasises the good and the bad in physiological systems. Prof. Redman has been present in all these areas of discovery and enlightenment as will be described.

Characterization of cytokine production by human term placenta macrophages in vitro

PROBLEM

Macrophages are apparently the only immune cells within placenta villi, yet functions of these cells remain obscure. It has been postulated that placental macrophages accomplish regulatory roles at the fetal-maternal interface by means of wide variety of secreted cytokines. We attempt to analyze the patterns of cytokine production in an isolated population of placental macrophages.

METHOD OF STUDY

Macrophages were obtained from term placentas in the absence of spontaneous labor. The basal and lipopolysaccharide (LPS)-stimulated levels of intracellular cytokines were detected by flow cytometry. The basal cytokine secretion was determined by BD Cytometry Bead Array (BD Biosciences, San Diego, CA, USA).

RESULTS

Intracellular IL-1alpha, IL-1beta, IL-6, and TNFalpha were detected in 31, 27, 4, and 3% CD68+ cells, respectively. Stimulation with LPS increased the proportions of cytokine-producing CD68+ cells to 48, 50, 28, and 49%, respectively. Under basal conditions, levels of released TNFalpha and IL-6, respectively, were 20- and 25-fold higher when compared with IL-1b while IL-10 was secreted in small but detectable amounts. When a secretory activity was estimated for cytokine-producing cells, the secretion rate for TNFalpha and IL-6 overwhelmingly surpassed that for IL-1beta (TNFalpha:IL-6:IL-1beta ratio was 192:145:1).

CONCLUSION

These results suggest functional heterogeneity of the placental macrophage population and contribute to the elucidation of regulatory roles of these cells in gestation.

Mechanisms of leukocyte accumulation and activation in chorioamnionitis: interleukin 1 beta and tumor necrosis factor alpha enhance colony stimulating factor 2 expression in term decidua

Chorioamnionitis is a major cause of prematurity as well as perinatal morbidity and mortality. The present study observed a marked increase in immunohistochemical staining for Colony Stimulating Factor 2 (CSF2; also known as granulocyte macrophage-colony stimulating factor), a potent neutrophil and macrophage chemoattractant and activator, in the decidua of patients with CAM compared with controls (n = 8; P = .001). To examine the regulation of this CSF2, cultured decidual cells primed with estradiol (E2) or E2 plus medroxyprogesterone acetate, were exposed to tumor necrosis factor-alpha or interleukin-1beta and secreted CSF2 measured by ELISA. Levels of CSF2 in E2 plus MPA-treated cultures increased 18- and 245-fold following treatment with TNF or IL1B (n = 7, P < .05). Quantitative RT-PCR demonstrated parallel changes in mRNA levels. This study reveals that CSF2 is strongly expressed in decidua from patients with CAM and indicates TNF or IL1B as important regulators of CAM-related decidual leukocyte infiltration and activation.

Role of TNF-α in human female reproduction

TNF-α is a highly versatile cytokine, playing an important role in both apoptosis and inflammation, which is central to reproduction. It belongs to the Th1 type of cytokines. Thus, TNF-α is a proinflammatory cytokine and is involved during follicle development and ovulation, corpus luteum formation and regression and cyclic endometrium function. It has been postulated to be detrimental to the survival of the conceptus due to apoptosis of human primary villous trophoblast cells, leading to miscarriage. However, TNF-α may have a dual role in early pregnancy. Hormonally regulated uterine TNF-α in the mother is probably essential for trophoblast cell invasion, while increased production of TNF-α by maternal macrophages may facilitate labor. The current knowledge on the role of TNF-α and its receptors in the female reproduction is described in this review.

Human tumour necrosis factor: physiological and pathological roles in placenta and endometrium

The cytokine tumour necrosis factor alpha (TNF) is a well known member of the TNF superfamily consisting of at least 18 ligands and 29 different receptors involved in numerous cellular processes. TNF signals through two distinct receptors TNFR1 and TNFR2 thereby controlling expression of cytokines, immune receptors, proteases, growth factors and cell cycle genes which in turn regulate inflammation, survival, apoptosis, cell migration, proliferation and differentiation. Since expression of TNF was discovered in amnion and placenta many studies demonstrated the presence of the cytokine and its receptors in the diverse human reproductive tissues. Whereas TNF has been implicated in ovulation, corpus luteum formation and luteolysis, this review focuses on the functions of TNF in human placental, endometrial and decidual cell types of normal tissues and also discusses its role in endometrial and gestational diseases. Physiological levels of the cytokine could be important for balancing cell fusion and apoptotic shedding of villous trophoblasts and to limit trophoblast invasion into maternal decidua. Regulation of the TNF/TNFR system by steroid hormones also suggests a role in uterine function including menstrual cycle-dependent destruction and regeneration of endometrial tissue. Aberrant levels of TNF, however, are associated with diverse reproductive diseases such as amniotic infections, recurrent spontaneous abortions, preeclampsia, preterm labour or endometriosis. Hence, concentrations, receptor distribution and length of stimulation determine whether TNF has beneficial or adverse effects on female reproduction and pregnancy.

Leptin, IL-10 and Inflammatory Markers (TNF-?, IL-6 and IL-8) in Pre-Eclamptic, Normotensive Pregnant and Healthy Non-Pregnant Women

PROBLEM

Despite progress in immunobiology, pre-eclampsia (PE) remains one of the most common reasons for women to die during pregnancy. The widespread pathophysiological mechanisms are endothelial dysfunction, oxidative stress and inflammation. The aim of this study was to assess the alteration in the levels of leptin, interleukin (IL)-10 and inflammatory cytokines [tumour necrosis factor (TNF)-alpha, IL-6 & IL-8] in pre-eclamptic (severe and mild), healthy pregnant and non-pregnant women and correlate these parameters with disease severity.

METHOD OF STUDY

The levels of leptin, IL-10 and inflammatory cytokines were measured by high sensitivity enzyme-linked immunoabsorbant assay. The study subjects were 54 pre-eclamptic women (ten severe and 45 milder), compared by age matched 50 healthy pregnant and 27 non-pregnant women. Kruskal-Wallis non-parametric analyses of variance followed by Mann-Whitney U-test were used for statistical analysis.

RESULTS

The levels of leptin, TNF-alpha, IL-6 & IL-8 in pre-eclamptic subjects were increased significantly when compared with the healthy control pregnant and non-pregnant (P < 0.000). The concentration of IL-10 has shown different pattern as its level decreased significantly (0.001) in pre-eclamptic women (overall) in comparison with control subjects (pregnant & non-pregnant). A combination of 80% or higher sensitivity and specificity was seen in the parameters analysed, except IL-8 and IL-10.

CONCLUSION

Our findings suggest a relationship among TNF-alpha, IL-6, IL-8, IL-10 and leptin and indicate that altered levels of above markers in PE might be used as markers of pro-inflammation/anti-inflammation and endothelial dysfunction in pre-eclamptic pregnancies. These results also advocate the abnormal leptin and cytokine responses in mother, which might be involved in the pathogenesis of PE.

Tumour Necrosis Factor-alpha Converting Enzyme in Human Gestational Tissues from Pregnancies Complicated by Chorioamnionitis

Chorioamnionitis increases the risk of preterm labour and is associated with adverse neonatal outcomes including cerebral palsy. Tumour necrosis factor-alpha (TNF-alpha) derived from the gestational tissues (placenta, fetal membranes and maternal decidua) is thought to play a pivotal role in the induction of cytokine response in chorioamnionitis. Tumour necrosis factor-alpha converting enzyme (TACE) is essential for the release of TNF-alpha. Our aim was to determine whether the expression of TACE is increased in human gestational tissues from pregnancies complicated by chorioamnionitis, and whether lipopolysaccharide (LPS) causes increased expression of TACE in the human gestational tissues in vitro. The immunostaining of TACE was generally more intense, in particular in the syncytiotrophoblast and stromal cells, in villous samples from pregnancies complicated by chorioamnionitis than those from normal pregnancies. Increased immunoreactivity of TACE was also noted in the amnion and choriodecidua. In parallel, there was an increased infiltration of monocytes/macrophages within the villous stroma and choriodecidua. As a complement to our in vivo findings, LPS significantly increased the levels of mRNA and protein of TACE in a dose-dependent response in villous and fetal membrane explant cultures. Together, our results imply a potential role of TACE in the pathogenesis of chorioamnionitis.

Cytokine secretion in decidual mononuclear cells from term human pregnancy with or without labour: ELISPOT detection of IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha

Cytokines are believed to be important in maintaining pregnancy and in the process of labour induction in humans. The aim of this study was to investigate the secretion of the cytokines interferon-gamma (IFN-gamma), interleukin-4 (IL-4), IL-10, transforming growth factor-beta (TGF-beta) and tumour necrosis factor-alpha (TNF-alpha) in decidual tissue with or without labour. Decidual tissue was collected from 32 healthy women undergoing elective caesarean sections before the onset of labour (n=17) or after normal vaginal delivery (n=15). Mononuclear cells were analysed for cytokine secretion with ELISPOT. To validate the widely used method of tissue collected at caesarean sections and after vaginal deliveries as a representative of before and after labour, respectively, placenta biopsies were collected from 12 healthy women to study the expression of the prostaglandin pathway enzymes cyclooxygenase-2 (COX-2) and microsomal prostaglandin E(2) synthase (mPGES). Decidual mononuclear cells from term human pregnancy spontaneously secrete IFN-gamma, IL-4, IL-10, TGF-beta and TNF-alpha. No difference was seen in cytokine secretion with or without labour, indicating that decidual leukocytes are not the main cell population responsible for plausible cytokine regulation in the process of termination of pregnancy. Placental tissues obtained after vaginal delivery showed a higher mRNA expression of the prostaglandin regulating molecules COX-2 and mPGES than tissues from caesarean sections before the onset of labour, validating that the model can be used as a representative of the state before and after labour.

TNFalpha-mediated induction of PAI-1 restricts invasion of HTR-8/SVneo trophoblast cells

The pro-inflammatory cytokine TNFalpha has numerous effects on placental trophoblasts. Here, we investigated the effects of the cytokine on gene expression and function of the extravillous trophoblast cell line HTR-8/SVneo. Wound healing and Matrigel invasion assays demonstrate that TNFalpha impairs motility and invasiveness. In contrast, counting of cumulative cell numbers and FACS analyses revealed that the cytokine did neither affect proliferation nor distribution of cell cycle phases. Immunocytochemistry of the cytokeratin 18 neo-epitope suggests that TNFalpha did not induce apoptosis in HTR-8/SVneo cells. Gelatine zymography and enzyme activity assays of supernatants of TNFalpha-treated cells demonstrate elevation of the pro- and active form of MMP-9 suggesting that increased expression of the protease cannot overcome the TNFalpha-inhibitory effect on cell invasion. Semi-quantitative RT-PCR analyses suggest that the cytokine may not alter mRNA levels of uPA and tPA. However, elevated expression of PAI-1 was detected by RT-PCR, as well as by Northern and Western blot analyses. Supplementation of PAI-1-blocking antibodies restored invasion of TNF-alpha-incubated HTR-8/SVneo cells through Matrigel-coated transwells. In addition, immunocytochemistry revealed nuclear accumulation of the p65 subunit of NFkappaB in the presence of the cytokine. EMSA indicated TNFalpha-induced binding of the inflammatory transcription factor to an NFkappaB consensus sequence and to the NFkappaB recognition site located in the PAI-1 promoter. The data suggest that TNFalpha restricts trophoblast invasion mainly by increasing the expression of PAI-1. Induction of the inhibitor may involve TNFalpha-stimulated activation of NFkappaB.

Th1/Th2 cytokines balance--yin and yang of reproductive immunology

For years conception of Th2 overbalance during pregnancy has been a paradigm for immunology of reproduction, while Th1 activity has been presented as unwanted component. Studies concerning Th1/Th2 balance in physiological and complicated pregnancy have been reviewed. Th1 activity during early peri-implantation period, premature and term labour not only accompanies but even predominates over Th2 activity. Th1 activity plays important role in promotion of Th2 response, regulation of placentation process, defense against infections and initiation of delivery. Together with Th2 activity it is necessary component of immunological reactions during pregnancy, both activities being inseparable like yin and yang. So paradigm of "Th1-Th2 cooperation" is much closer to reality than "Th2 phenomenon".

The effect of vascular origin, oxygen, and tumour necrosis factor alpha on trophoblast invasion of maternal arteries in vitro

Extravillous trophoblasts (EVTs) invade and remodel uterine spiral arteries. Regulatory factors may include inherent vessel susceptibility, local oxygen levels and tumour necrosis factor alpha (TNFalpha). We have used an in vitro model to investigate interstitial and endovascular invasion of myometrial spiral arteries from pregnant and non-pregnant uteri and also omental arteries. To model endovascular invasion, fluorescent-labelled EVTs were perfused into the lumen of these dissected vessels. For interstitial invasion, labelled EVTs were layered on top. Cultures were either maintained in 17% or 3% oxygen, or cultured with TNFalpha. The invasion of arteries from pregnant women occurred via both routes at 17% oxygen, with endovascular invasion more efficient than interstitial. In omental arteries and spiral arteries from non-pregnant women, endovascular invasion was limited. Endovascular and interstitial invasion were lower in all arteries at 3% oxygen. Typically, endovascular events were clustered, with an associated disruption in the adjacent endothelium and smooth muscle. A role for TNFalpha in limiting invasion was also supported. In conclusion, priming of uterine arteries may be necessary prior to EVT invasion. Oxygen is a sensitive regulator within this physiological model and increased invasion at higher pO2 may explain the homing of EVT to maternal arteries rather than veins. Adequate vascular transformation may therefore rely on a balance between vascular receptivity, oxygen partial pressure, and exposure to inflammatory mediators.

Immunological properties of human decidual macrophages--a possible role in intrauterine immunity

Our aim was to investigate the contribution of decidual macrophages, which constitute an important immune component of the decidua in late gestation, to intrauterine defence mechanisms. Using flow cytometry we examined the ability of decidual macrophages, isolated from term decidua, to bind and phagocytose fluorescence-labelled bacterial and yeast bioparticles. We also assessed their ability to generate superoxide radicals and tumour necrosis factor-alpha following lipopolysaccharide challenge. Decidual macrophages bound bacterial and yeast particles in a dose-dependent manner, which subsequently led to phagocytosis. These macrophages also produced superoxide radicals and the pro-inflammatory cytokine TNF-alpha when challenged with bacterial lipopolysaccharides. These results suggest a role for decidual macrophages in pathogen recognition and clearance during pregnancy, and, therefore, they are likely to protect the fetus against intrauterine infections which might otherwise lead to preterm labour.

Role of tumor necrosis factor-α in Gram-negative bacterial lipopolysaccharides induced implantation failure

Background and aims:  Gram-negative bacterial lipopolysaccharides (LPS) are known causative agents for pregnancy loss in mothers with genital tract infections. In this study, we attempt to test the role of tumor necrosis factor-α (TNF-α) in the normal physiological processes of preimplantation embryonic development and LPS induced pregnancy loss in mice. Since the preimplantation mouse embryos grow in an unattached state for a considerable period (day 1-4.5) of its development in the maternal environment, it is possible that a critical level of soluble and biologically active TNF-α is maintained in the maternal environment, and that any alteration in this could lead to implantation failure. Here we determine the pattern and level of expression of TNF-α gene in preimplantation stage embryos and uterus collected from control and LPS treated pregnant animals during different stages of preimplantation period of pregnancy by reverse transcriptase-polymerase chain reaction. Methods:  The concentrations and biological activity of soluble TNF-α protein present in oviductal fluid (OF) and uterine fluid (UF), in the normal and LPS treated animals, were determined by enzyme-linked immunosorbent assay and 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide assay on L929 cells, respectively. TNF-α was also given i.p. to study its effect on implantation. Results:  An early expression of TNF-α messenger ribonucleic acid in the preimplantation stage embryos collected from LPS treated animals was observed along with a significant rise in the level of biologically active soluble TNF-α in the OF. Similarly, the level of bioactive and soluble TNF-α present in the UF from LPS treated animals was significantly higher as compared to the control on day 4.42 of pregnancy. Conclusions:  TNF-α given i.p. exerted similar effects on pregnancy as that of LPS. An incessant exposure of the preimplantation stage embryos to significantly high levels of maternal bioactive free/soluble TNF-α, and an alteration in the normal pattern of its expression in the preimplantation stage embryos may be one of the causes of failure of implantation leading to poor pregnancy outcome in LPS treated mouse. (Reprod Med Biol 2005; 4: 79- 89).

Role of tumor necrosis factor-α in Gram-negative bacterial lipopolysaccharides induced implantation failure

Background and aims:  Gram-negative bacterial lipopolysaccharides (LPS) are known causative agents for pregnancy loss in mothers with genital tract infections. In this study, we attempt to test the role of tumor necrosis factor-α (TNF-α) in the normal physiological processes of preimplantation embryonic development and LPS induced pregnancy loss in mice. Since the preimplantation mouse embryos grow in an unattached state for a considerable period (day 1-4.5) of its development in the maternal environment, it is possible that a critical level of soluble and biologically active TNF-α is maintained in the maternal environment, and that any alteration in this could lead to implantation failure. Here we determine the pattern and level of expression of TNF-α gene in preimplantation stage embryos and uterus collected from control and LPS treated pregnant animals during different stages of preimplantation period of pregnancy by reverse transcriptase-polymerase chain reaction. Methods:  The concentrations and biological activity of soluble TNF-α protein present in oviductal fluid (OF) and uterine fluid (UF), in the normal and LPS treated animals, were determined by enzyme-linked immunosorbent assay and 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide assay on L929 cells, respectively. TNF-α was also given i.p. to study its effect on implantation. Results:  An early expression of TNF-α messenger ribonucleic acid in the preimplantation stage embryos collected from LPS treated animals was observed along with a significant rise in the level of biologically active soluble TNF-α in the OF. Similarly, the level of bioactive and soluble TNF-α present in the UF from LPS treated animals was significantly higher as compared to the control on day 4.42 of pregnancy. Conclusions:  TNF-α given i.p. exerted similar effects on pregnancy as that of LPS. An incessant exposure of the preimplantation stage embryos to significantly high levels of maternal bioactive free/soluble TNF-α, and an alteration in the normal pattern of its expression in the preimplantation stage embryos may be one of the causes of failure of implantation leading to poor pregnancy outcome in LPS treated mouse. (Reprod Med Biol 2005; 4: 79- 89).

Secretion of tumor necrosis factor-alpha from human placental tissues induced by hypoxia-reoxygenation causes endothelial cell activation in vitro: a potential mediator of the inflammatory response in preeclampsia

Preeclampsia is a hypertensive complication of human pregnancy characterized by generalized maternal endothelial cell activation. Circulating pro-inflammatory cytokines derived from the placenta are thought to play a key role. We recently demonstrated that hypoxia-reoxygenation (H/R) of placental tissues in vitro causes equivalent oxidative stress to that seen in preeclampsia. Our aim was to determine whether H/R also increases production of tumor necrosis factor-alpha (TNF-alpha), and whether conditioned media from samples exposed to H/R causes activation of human umbilical vein endothelial cells (HUVECs). Concentrations of mRNA encoding TNF-alpha were significantly higher in placental tissues subjected to H/R compared to hypoxic or normoxic controls. Although there was no difference in the concentrations of TNF-alpha protein in tissue homogenates, levels of TNF-alpha protein in the medium were significantly higher after H/R compared to controls, indicating increased secretion. Furthermore, conditioned medium from samples subjected to H/R caused increased expression of E-selectin by HUVECs, and the addition of anti-TNF-alpha antibodies significantly reduced that activation. These results are consistent with our hypothesis that intermittent perfusion of the placenta, secondary to reduced trophoblast invasion, causes increased secretion of TNF-alpha, and that this contributes to the activation of maternal endothelial cells that characterizes preeclampsia.

Neither lymphotoxin alpha nor lymphotoxin beta receptor expression is required for biogenesis of lymphoid aggregates or differentiation of natural killer cells in the pregnant mouse uterus

Gene ablation studies in mice indicate that lymphotoxin (LT)alpha, LTbeta and LTbetaR are essential for the genesis of lymph nodes (LN), normal structural development of peripheral lymphoid tissues and the differentiation of natural killer (NK) cells. LTbetaR binds to the heterotrimeric cytokines LTalpha1beta2 and LIGHT. LTs also regulate stromal cell expression of lymphocyte homing chemokines. Uterine decidualization in normal (+/+) mice is accompanied by the appearance and maturation of large numbers of uterine NK (uNK) cells that differentiate from precursors mobilized to the uterus from secondary lymphoid tissues. uNK cells accumulate in a transient, lymphocyte-rich region known as the metrial gland or, more recently, the mesometrial lymphoid aggregrate of pregnancy (MLAp). To determine if LTs contribute to development of the MLAp, and to the differentiation and/or localization of uNK cells, a histological study was undertaken of implantation sites from LTalpha null, LTbetaR null and gestation day-matched, normal mice. Implantation sites from the gene-ablated mice contained abundant numbers of uNK cells that localized appropriately. This indicates that the stromally derived molecules supporting NK cell differentiation in the uterus differ from those used in secondary lymphoid organs.

Interleukin-13 and tumor necrosis factor-beta differentially regulate the production of cytokines by cultured human endometrial stromal cells

OBJECTIVE

To evaluate the effects of interleukin (IL)-13, a T-helper (Th)2 cytokine, and tumor necrosis factor (TNF)-beta, a Th1 cytokine, on the production of IL-6 family cytokines and chemokines by endometrial stromal cells (ESC).

DESIGN

The effects of IL-13 and TNF-beta, on the production of IL-6, IL-11, leukemia inhibitory factor (LIF), IL-8, growth-regulated oncogene alpha (GROalpha), monocyte chemoattractant protein-1 (MCP-1), regulated on activation, T-cell expressed and secreted (RANTES), and eotaxin were investigated.

SETTING

Research laboratory at a medical university.

PATIENT(S)

Thirteen endometrial specimens in the late proliferative phase were used.

INTERVENTION(S)

The ESC were incubated for 24 hours with recombinant human IL-13 and recombinant human TNF-beta.

MAIN OUTCOME MEASURE(S)

The concentration of IL-6, IL-11, LIF, IL-8, GROalpha, MCP-1, RANTES, and eotaxin in the culture media was measured using ELISA.

RESULT(S)

The increase in levels of IL-6, IL-8, MCP-1, and eotaxin in the culture media of ESC paralleled the addition of increasing amounts of IL-13 and TNF-beta, whereas the levels of IL-11 and LIF were decreased with increasing amounts of IL-13, but were increased with increasing amounts of TNF-beta. Tumor necrosis factor-beta enhanced the production of GROalpha and RANTES in dose-dependent manner; however, IL-13 did not affect the expression of GROalpha or RANTES.

CONCLUSION(S)

These results suggest that IL-13 and TNF-beta secreted in the cyclic endometrial tissue and in the decidua may differentially regulate the production of IL-6 family cytokines and chemokines by ESC. The controlled expression of these cytokines in the endometrium may contribute to the modulation of the immune reaction during the menstrual cycle and in early pregnancy by the regulation of leukocyte trafficking and functions.

Cytokines of the placenta and extra-placental membranes: biosynthesis, secretion and roles in establishment of pregnancy in women

Virtually all known cytokines have been demonstrated to be expressed in the placenta and associated fetal and maternal membranes during normal gestation. In addition to playing their traditional roles as modulators of immunological function, cytokines derived from the placenta and extraplacental membranes, together with other locally-derived growth factors, appear to be implicated in various aspects of implantation and placental development. Imbalances in the intrauterine cytokine milieu around the time of implantation and invasion may play a causative role in disorders associated with early pregnancy failure, and are also associated with the abnormal trophoblast development seen in gestational trophoblastic disease. Cytokines thus appear to be an important component of a paracrine/autocrine communication network operating within the feto-maternal interface to ensure the successful establishment of pregnancy.

Flow cytometric measurement of intracellular Th1 and Th2 cytokine production by human villous and extravillous cytotrophoblast

A wide variety of cytokines are present at the maternal-fetal interface, but the extreme cellular complexity of the placenta has made it difficult to determine which cytokines are produced by which cells. Hence novel flow cytometric methods have been applied to determine intracellular cytokine production by specific cell-types in placental cell suspensions. Cell suspensions were prepared from first and third trimester chorionic villi and third trimester amniochorion by enzymatic digestion and Percoll density gradient centrifugation. After overnight incubation in the presence of monensin, cells were fixed, permeabilized and labelled with antibodies for villous cytotrophoblast (cytokeratin+, MHC class I-), extravillous cytotrophoblast (cytokeratin+, MHC class 1+) and leucocytes (CD45+). These cell types were further characterized by their expression of EGFR (proliferative cytotrophoblast) and c-erbB2 (invasive cytotrophoblast). Production of IL-4, IL-10, TNF-alpha, IFN-gamma and IL-12 was determined by simultaneous labelling with the appropriate monoclonal antibodies. Only IL-4 was detected consistently in all samples of cytotrophoblast. IL-10 was not detected but IL-10 mRNA was demonstrated in third trimester chorionic villus digests by RT-PCR. Although IL-4 secretion has not been demonstrated, these data suggest that, in vivo there may be a "Th2 type cytokine bias" orchestrated by the trophoblast. It is proposed that other cytokines (including IL-10 and TNF-alpha) are produced by decidual leukocytes, and not cytotrophoblast, at the maternal-fetal interface.

Preterm labour and delivery: a genetic predisposition

Preterm delivery (PTD) complicates as many as 10% of pregnancies in the United States. Moreover, prematurity accounts for more than 70% of the consequent neonatal and infantile morbidity and mortality. Serious long-term complications include cerebral palsy, respiratory disease, blindness and deafness. Despite substantial basic scientific, translational and clinical investigation in recent years, the PTD rate (10%) and the low birthweight rate (7%) remain largely unchanged. Indeed, the very aetiology and pathophysiology of PTD remain unknown in most cases. In short, PTD continues to constitute a major clinical and public health challenge of the highest order, a circumstance further compounded by the controversy surrounding the efficacy of current therapeutic regimens. In an effort to address the relevant knowledge gap, we put forth the hypothesis that PTD results, at least in part, from a genetic predisposition. Evidence supporting the hypothesis that certain women have a genetic predisposition to deliver preterm is growing. Moreover, the discovery of a gene mutation predisposing to PTD would constitute a major breakthrough for future research into the biology, prediction, and therapy of preterm labour. Presented here is a discussion of the evidence to support a genetic predisposition to PTD, molecular techniques proposed to study the genetics of preterm labour, and plausible candidate genes that warrant further investigation.

Increased production of tumor necrosis factor-alpha TNF-alpha by IUGR human placentae

OBJECTIVE

To evaluate the effect of pathological placental conditions such as intrauterine growth restriction (IUGR) or exposure to angiotensin II (AII) on TNF-alpha secretion in the vasculature of isolated human placental cotyledons.

STUDY DESIGN

Isolated placental cotyledons from 10 normal and four intrauterine growth restricted fetuses were dually perfused. Perfusate samples from the fetal circulation were collected every 30 min during 120 min. TNF-alpha levels in the fetal-placental perfusate were evaluated using specific commercial ELISA kits. In three additional normal placentae, bolus injections of angiotensin II (10(-9)-10(-4) mol/l) were given into the fetal-placental circulation and perfusate samples were collected. Statistical significance of difference TNF-alpha levels between different conditions was determined by analysis of variance (ANOVA) and paired t-test.

RESULTS

TNF-alpha levels were significantly higher in the perfusate of IUGR placentae as compared with normal placentae after 120 min of perfusion (mean 410+/-121 vs. 39+/-14 pg/ml, P=0.005). There was a significant dose-dependent increase in TNF-alpha levels in the placental perfusate after a bolus injection of AII 66 pg/ml with AII 10(-9) mol/l vs. 97 pg/ml with AII 10(-5) mol/l (P=0.004), respectively.

CONCLUSIONS

Placental pathology related to condition IUGR might induce the secretion of proinflammatory cytokines such as TNF-alpha, which may enhance the vasoconstriction of the fetal placental vascular bed.

Formation of proinflammatory cytokines in human term myometrium is stimulated by lipopolysaccharide but not by corticotropin-releasing hormone

Human term myometrium is poorly characterized as a source of proinflammatory mediators involved in parturition. We have investigated the basal expression of cytokines in myometrium, as well as the effects of CRH and lipopolysaccharide (LPS) on cytokine release. Explants from term myometrium were challenged with CRH or LPS (1 microg/mL each) in short-term tissue culture. Interleukin (IL)-1beta++, IL-6, IL-8, and tumor necrosis factor (TNF)alpha concentrations in the medium were quantified by enzyme immunoassay. The major cytokines released after 24 h were IL-6 and IL-8. All cytokines investigated were stimulated significantly by LPS (P: < 0. 05) but not by CRH. Messenger RNA levels of these cytokines were investigated by RT-PCR. IL-1beta+ and IL-6 messenger RNA were present in preterm and term myometrium before and during labor, whereas IL-8 and TNFalpha were expressed only by myometrium in active labor. Furthermore, myometrial CRH receptors and macrophages were characterized immunohistochemically. We conclude that human term myometrium is a site of production of proinflammatory cytokines and is involved in the inflammation-like reactions mediating the birth process. Cytokine release in term myometrium seems not to be under control of CRH.

TNF-alpha/TNFRI in primary and immortalized first trimester cytotrophoblasts

During the first trimester of pregnancy endogenous expression of tumour necrosis factor (TNF)-alpha has been detected in villous, as well as in proliferating and invading extravillous, trophoblasts suggesting that the protein could be involved in trophoblast differentiation. To gain insights into the putative role of the TNF-alpha signalling pathway, we investigated expression of its receptors, TNFR I and II, in first trimester placentae and early trophoblasts, and studied the influence of the cytokine on cell proliferation and apoptosis. ELISA and RT-PCR revealed secretion/expression of TNFRI protein/mRNA in immortalized ED27 cells and purified first trimester cytotrophoblasts, while soluble TNFRII was undetectable in cell culture supernatants. In agreement, immunohistochemical analyses of first trimester placentae showed that TNFRI is localized to the villous cyto- and syncytiotrophoblast, to the proliferating cytotrophoblasts of the cell islands and cell columns, as well as to extravillous cells invading decidual tissue. TNFRII, however, was absent in early trophoblast populations. Interleukin (IL)-1 and phorbol 12-myristate 13-acetate (PMA) induced shedding of TNFRI from ED27 and primary cells suggesting that under inflammatory conditions the soluble receptor protein may protect from cytotoxic effects of TNF-alpha. Upon incubation with increasing amounts of TNF-alpha no significant changes in DNA-content or cell numbers were found, suggesting that the cytokine does not augment proliferation of primary cytotrophoblasts. High doses of TNF-alpha, however, provoked growth arrest in ED27 cells as evaluated by cell counting, but did not induce necrosis/apoptosis as was assessed by TUNEL assay. In first trimester cells addition of elevated amounts of TNF-alpha resulted in the appearance of TUNEL-positive cells and an increase in caspase-3 enzyme activity suggesting that the TNF-alpha-dependent apoptotic cascade is executed in a portion of the early cytotrophoblasts.

Tumor necrosis factor-alpha and its receptor in the corpus luteum of pregnant cows

The objective of this study was to investigate the presence of tumor necrosis factor (TNF)-alpha mRNA and TNF-alpha receptors in the bovine corpus luteum (CL) during the gestation period. TNF-alpha mRNA and TNF-alpha receptors were determined on bovine CL from pregnant cows at three stages: trimester I (fetal crown-rump length; 6-20 cm), trimester II (25-45 cm) and trimester III (50-80 cm). TNF-alpha mRNA was detected by an RT-PCR analysis in the CL of all stages of gestation. A Scatchard analysis revealed the presence of a high-affinity binding site (Kd; 5.1-6.9 nM) in the CL membranes collected at each stage of gestation. Furthermore, the concentrations of TNF-alpha receptors in the CL of trimesters I (24. 0 +/- 1.95 pmol/mg protein) and III (21.6 +/- 2.39 pmol/mg protein) of gestation were significantly higher than the concentration in trimester II (14.9 +/- 2.07 pmol/mg protein) (P < 0.05). These results indicate that TNF-alpha is locally produced and that TNF-alpha receptors are present in bovine CL during the gestation period, and suggest that TNF-alpha plays one or more roles as a paracrine factor in regulating bovine CL function during the entire gestation period.

Evidence of a nonendothelial source of nitric oxide in the isolated perfused hindlimb vasculature of the pregnant rat

OBJECTIVE

This study was undertaken to further elucidate the roles of the vascular endothelium and nitric oxide (NO) in the regulation of vascular tone and constrictor responsiveness in pregnancy.

METHODS

The perfusion pressure-flow relationship was measured in isolated, perfused, norepinephrine-constricted (1) endothelium-intact, (2) endothelium-denuded, and (3) N omega-nitro-L-arginine methyl ester (L-NAME)-treated hindlimbs from nonpregnant and term-pregnant rates.

RESULTS

Baseline perfusion pressure at a flow rate of 2 mL/min was similar (approximately 20 min Hg) in all hindlimbs. Norepinephrine (0.5 muM) increased perfusion pressure in both nonpregnant (+21.6 +/- 2.4 mm Hg) and pregnant (+13.6 +/- 0.9 mm Hg) endothelium-intact rat hindlimbs. In nonpregnant rat hindlimbs, endothelium removal and L-NAME increased norepinephrine vasoconstriction similarly (+44.3 +/- 4.0 mm Hg and +46.4 +/- 8.6 mm Hg, respectively). In pregnant-rat hindlimbs, L-NAME increased norepinephrine vasoconstriction by 43.5 +/- 10.8 mm Hg, similar to that in nonpregnant-rat hindlimbs, but endothelium removal only increased norepinephrine vasoconstriction by 28.0 +/- 2.2 mm Hg. Perfusion pressure increased linearly as the flow rate was increased from 2 to 4 mL/min, and the slope of the regression line of the endothelium-intact pregnant-rat hindlimbs (7.0 +/- 0.6) was slightly, but not significantly, lower than that of the nonpregnant-rat hindlimbs (9.6 +/- 0.9). Endothelium removal increased the slopes of the regression lines, but that of pregnant-rat hindlimbs (12.8 +/- 1.6) was significantly lower (p < or = 0.05) than that of the nonpregnant-rat hindlimbs (23.8 +/- 1.8). L-NAME caused a similar increase in the pressure-flow slopes of nonpregnant-rat (36.5 +/- 3.4) and pregnant-rat (32.1 +/- 5.3) hindlimbs.

CONCLUSIONS

These results suggest that nonendothelial nitric oxide production may be increased in the hindlimb resistance vasculature of the pregnant rat, which may play a role in the normal pregnancy blunting of constrictor responsiveness and reduction of vascular resistance.

Localization of p43 placental isoferritin in human maternal-fetal tissue interface

OBJECTIVE

Human placental isoferritin, which is composed of a 43-kd protein subunit, is exclusively reactive with the CM-H9 monoclonal antibody. The p43 exerts immunosuppressive activity during pregnancy. The aim of this study was to localize the expression of p43 in the maternal-fetal tissue interface during normal gestation.

STUDY DESIGN

Villous tissues samples were collected between 5 and 20 weeks' gestation and at term from uncomplicated pregnancies. Immunohistochemical localization of p43 was performed with CM-H9 monoclonal antibody.

RESULTS

During the first trimester p43 was highly expressed in syncytiotrophoblast, Hofbauer cells, and decidual macrophages. From 15 weeks' gestation onward expression in the syncytiotrophoblast was below the level of detection; however, p43 was demonstrated in villous Hofbauer cells and decidual macrophages throughout gestation.

CONCLUSIONS

Expression of p43 was demonstrated on both sides of the maternal-fetal tissue interface, with localization dependent on gestational age. This may suggest its immunologic function throughout pregnancy. First-trimester syncytiotrophoblast displayed high p43 levels, which disappeared later on, whereas maternal serum p43 level continued to increase, which suggests an extraplacental source for p43.