Gestational age-dependent expression of IL-10 and its receptor in human placental tissues and isolated cytotrophoblasts

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) enhances placental inflammation

Preterm birth is a leading cause of perinatal morbidity and mortality that is often associated with ascending infections from the lower genital tract. Recent studies with animal models have suggested that developmental exposure to the environmental toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can increase the risk of preterm birth in the offspring. How TCDD may modify placental immunity to ascending infections is unclear. Therefore, we studied the effects of TCDD treatment on basal and Escherichia coli-stimulated cytokine production by placental explants. Cultures of second-trimester placentas were treated with up to 40 nM TCDD for 72 h and then stimulated with 10(7)CFU/ml E. coli for an additional 24h. Concentrations of cytokines and PGE2 were measured in conditioned medium by immunoassay. TCDD exposure increased mRNA levels of IL-1β by unstimulated cultures, but no effects on protein levels of this cytokine were detected. TNF-α production was unaffected by TCDD for unstimulated cultures, but pre-treatment with 40 nM TCDD significantly increased E. coli-stimulated TNF-α production. Both basal and bacteria-stimulated PGE2 and COX-2 gene expression were enhanced by TCDD pretreatment. In contrast, production of the anti-inflammatory cytokine, IL-10, was reduced by TCDD pretreatment for both unstimulated and E. coli-stimulated cultures. No effect of TCDD on the viability of the cultures was detected. These results suggest that TCDD exposure may shift immunity to enhance a proinflammatory phenotype at the maternal-fetal interface that could increase the risk of infection-mediated preterm birth.

Change in mononuclear leukocyte responsiveness in midpregnancy and subsequent preterm birth

OBJECTIVE

To estimate the associations of change in immune response with preterm delivery, omega-3 supplementation, and fish diet.

METHODS

This was an ancillary study to a randomized trial of omega-3 fatty acid supplementation for the prevention of recurrent preterm birth. In vitro maternal peripheral blood mononuclear leukocyte production of the anti-inflammatory cytokine, interleukin-10, and the proinflammatory cytokine, tumor necrosis factor-α, in response to stimulation with lipopolysaccharide, was measured at 16-22 weeks of gestation (baseline) and again at 25-28 weeks of gestation (follow-up) among women with prior spontaneous preterm birth. Changes in concentrations from baseline to follow-up ([INCREMENT]) were compared separately among groups defined by gestational age category at delivery, fish diet history, and omega-3 compared with placebo treatment assignment with Kruskal-Wallis tests.

RESULTS

Interleukin-10 [INCREMENT] differed by gestational age category among 292 women with paired assays. Concentrations increased less in women delivering between 35 and 36 6/7 weeks of gestation (48.9 pg/mL) compared with women delivering at term (159.3 pg/mL) and decreased by 65.2 pg/mL in women delivering before 35 weeks of gestation (P=.01). Tumor necrosis factor-α Δ also differed by gestational age category among 319 women, but the pattern was inconsistent. Those delivering between 35 and 36 6/7 weeks of gestation exhibited decreased concentrations of tumor necrosis factor-α at follow-up compared with baseline (-356.0 pg/mL); concentrations increased among women delivering before 35 weeks of gestation and those delivering at term, 132.1 and 86.9 pg/mL (P=.03). Interleukin-10 Δ and tumor necrosis factor-α Δ were unaffected by either omega-3 supplementation or fish diet.

CONCLUSION

Recurrent preterm birth was associated with decreased peripheral blood mononuclear leukocyte production of interleukin-10 in response to a stimulus during the second trimester.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135902.

LEVEL OF EVIDENCE

II.

Evaluation of serum concentrations of interleukin (IL)-4, IL-10, and IL-12 during pregnancy in bitches

Complex cytokine networks play an important role in a wide range of pregnancy-related processes. During physiological pregnancy, the balance of T helper lymphocytes Th1 and Th2 is strongly shifted toward Th2, which has a protective role in the feto-maternal interaction. The aim of the present study is to establish the serum concentrations, ranges, and trends of anti-inflammatory interleukin (IL)-4 and IL-10, and inflammatory IL-12A, during three phases of gestation in the bitch (20-30, 31-40, and 41-57 days of gestation). Our results indicate that, in early gestation, IL-4 and -10 serum concentrations are elevated and might depend on progesterone that could act as a potent inhibitor of Th1 responses inducing, conversely, the production of Th2-type cytokines (i.e., IL-10 and IL-4). On the other hand, between 30 and 40 days of gestation, the concentrations of the anti-inflammatory ILs decrease probably because of high concentrations of prolactin, which is endowed with immunostimulatory properties on different immune cell types. In the third phase of gestation (41-57 days), an increase in IL-10 occurs, which might depend on high levels of 17β-estradiol that, during pregnancy, interfere with the ability of dendritic cells to stimulate T lymphocytes, acting as an anti-inflammatory factor. Conversely, the low and persistent concentrations of inflammatory IL-12A, throughout pregnancy, compared with anti-inflammatory ILs, might depend on the characteristic cytokine products of Thl and Th2 cells that are known to be mutually inhibitory. The monitoring of immunological status via the levels of cytokines during pregnancy in the bitch, could represent a diagnostic tool to predict and/or prevent pregnancy abnormality, as demonstrated in women.

Silibinin attenuates oxidative metabolism and cytokine production by monocytes from preeclamptic women

Silibinin is a polyphenolic plant flavonoid with anti-inflammatory properties. The present study investigated the effect of silibinin on oxidative metabolism and cytokine production - tumor necrosis factor-alpha (TNF-α), interleukin (IL)12, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, IL-10, and transforming growth factor beta (TGF-β1) - by peripheral blood monocytes (PBM) from preeclamptic pregnant women. It is a case-controlled study involving women with preeclampsia (PE, n = 30) compared with normotensive pregnant (NT, n = 30) and with non-pregnant (NP, n = 30) women. Monocytes were obtained and cultured with or without silibinin (5 μM or 50 μM) for 18 h. Superoxide anion (O2-) and hydrogen peroxide (H2O2) release were determined by specific assays, and cytokine levels were determined by immunoenzymatic assays (ELISA). Monocytes from preeclamptic women cultured without stimulus released higher levels of O22, H2O2 and TNF-α, and lower levels of IL-10 and TGF-β1 than did monocytes from NT and NP women. Treatment in vitro with silibinin significantly inhibited spontaneous O2- and H2O2 release and TNF-α production by monocytes from preeclamptic women. The main effect of silibinin was obtained at 50 μM concentration. Thus, silibinin exerts anti-oxidative and anti-inflammatory effects on monocytes from preeclamptic pregnant women by inhibiting the in vitro endogenous release of reactive oxygen species and TNF-α production.

Expression of inflammatory cytokines in placentas from pregnancies complicated with preeclampsia and HELLP syndrome

OBJECTIVE

To investigate the expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) in villous trophoblast, syncytial knots and decidua placentas from pregnancies complicated with preeclampsia (PE), Hemolysis, Elevated Liver enzymes and Low Platelet count (HELLP) syndrome and gestational age-matched controls.

METHODS

Study group included 35 placentas from pregnancies complicated with PE and 35 placentas from pregnancies with HELLP syndrome. Control group included 35 placentas from idiopathic preterm labor. Placentas were matched according to the gestational age. Expression of TNF-α, IL-6 and IL-10 was determined by immunohistochemistry and semi-quantitative HSCORE method in villous trophoblast, syncytial knots and decidua. Non-parametric statistics were used for analyses.

RESULTS

There was no difference in the expression of TNF-α, IL-6 and IL-10 in all the studied placental segments between PE, HELLP and gestational age-matched control group. TNF-α (F = 32, 41, p < 0.001), IL-6 (F = 58, 53, p < 0.001) and IL-10 (F = 17, 62, p < 0.001) expression was significantly different in different placental cell types, the highest expression of cytokines was in decidua.

CONCLUSION

There was no difference in cytokine expression in villous trophoblast, syncytial knots and decidua among the studied placental groups. The expression of cytokines was highest in decidua in all the studied placental groups.

The entry of fetal and amniotic fluid components into the uterine vessel circulation leads to sterile inflammatory processes during parturition

Pro-inflammatory cytokines play an important role during the process of human parturition. The focus of this review was to explore the contribution of biological, biochemical, and genetic changes in the onset of term labor. This article reviews the English-language literature on inflammatory, hormonal, and immunological factors in an effort to identify the molecular basis of human parturition. The majority of the genes and proteins up-regulated in parturition at term are related to four functional categories, mechanical stretch-mediated damage-associated molecular patterns (DAMPs) activation, response to immunity, induction of inflammatory signaling, and progressive uterine myometrial contractility and resultant term birth. Mechanical stretch could promote the entry of amniotic fluid components into the uterine vessel circulation that is the common physiologic mechanism at term prior to labor. The fetal or amniotic fluid-derived DAMPs could activate the immune system. The inflammatory mediators are produced by infiltrating activated leukocytes and by the reproductive tissues themselves such as myometrium, and subsequently lead to uterine contractions. This review supports the sterile inflammation hypothesis that there are at least two phases of human parturition: the initial wave of the entry of amniotic fluid components into uterine vasculatures would be followed by the second big wave of subsequent myometrial contraction.

Role of molecular mimicry and polyclonal cell activation in the induction of pathogenic β2-glycoprotein I-directed immune response in Balb/c mice upon hyperimmunization with tetanus toxoid

It is known that tetanus toxoid (TTd)-hyperimmunization induces increased titer of sera β2-glycoprotein I (β2GPI)-specific antibodies (Abs) in Balb/c mice. The concentrations of such induced anti-β2GPI Abs as well as their pathogenic potential are strongly influenced by the context of TTd application. β2GPI-specific immune response is established as a part of TTd-specific immune response by molecular mimicry mechanism due to structural homology between TTd and β2GPI. This finding is supported by the following facts: (1) cross-reactive Abs that recognize both TTd and β2GPI epitopes are present in Balb/c mice sera; (2) anti-TTd Abs secretion in splenic cultures is induced after β2GPI stimulation and vice versa. However, analyses of (1) IL-10 production following in vitro stimulation of immunized Balb/c mice splenocytes by TTd, β2GPI or glutaraldehyde-treated β2GPI and (2) specific impact of ConA and agonists of TLR2, TLR4, and TLR9 on anti-TTd and autoreactive Abs secretion strongly imply that these two branches of the TTd-induced immune response do not use identical cell populations and are regulated in a different way. Results presented in this paper describe that structural homology between foreign and self-antigens could focus mounted autoreactive immune response toward specific self-structure, but the context of antigen application, including a history of previous immune stimulations and adjuvants applied together with the antigen, are the main factors which determine the outcome of the induced immune response.

Cytokines and chemokines production by mononuclear cells from parturient women after stimulation with live Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasite that can cause variable clinical symptoms or can even be asymptomatic in immunocompetent individuals. More severe symptoms are observed in immunocompromised patients and congenital transmission of the parasite has been reported. The objective of this study was to evaluate the response of peripheral blood mononuclear cells (PBMC) in parturient and non-pregnant women exposed to live tachyzoites of T. gondii strain RH or ME49. PBMC were isolated from parturient and non-pregnant women with negative or positive serology for toxoplasmosis and cultured with live tachyzoites of the two T. gondii strains for 24 h. Next, the cell culture supernatants were collected and levels of CCL2, CCL5, IL-6, IL-10, IL-12, and TNF-α produced by PBMC after tachyzoite exposure were measured. Live tachyzoite forms of T. gondii significantly inhibited the synthesis of CCL2 in seropositive parturient women, whereas a stimulatory effect on CCL5 was observed in seronegative parturient women. Cells from T. gondii-seronegative non-pregnant women produced significantly higher levels of TNF-α and IL-12, demonstrating the proinflammatory profile induced by the presence of the parasite in culture. The results suggest that the immunomodulation seen during pregnancy contributes to the development of an environment that facilitates escape of the parasite from the immune response.

Ontogeny and the effects of in utero brain ischemia on interleukin-1β and interleukin-6 protein expression in ovine cerebral cortex and white matter

Interleukin (IL)-1β and IL-6 have been implicated in brain development, injury progression, and fetal/maternal immune interactions. We examined IL-1β and IL-6 protein expression in cerebral cortex (CC) and white matter (WM) from non-ischemic ovine fetuses at 87-90, 122-127, and 135-137 days of gestation, pregnant ewes at 87-90 and 135-137 days of gestation, and fetuses exposed to 48 or 72h of reperfusion after ischemia. Protein expression was determined by Western immunoblot. In non-ischemic CC, IL-1β was higher (P<0.05) in adult sheep and fetuses at 135-137 than 87-90 and 122-127 days, and IL-6 higher at 122-127 than 87-90 days, and in adults than fetuses at 87-90, 122-127, and 135-137 days of gestation. In non-ischemic fetal WM, IL-6 was higher at 135-137 than 87-90 days, but IL-1β did not differ. In CC, IL-1β was higher in ewes at 135-137 than 87-90 days and IL-6 at 135-137 days and in non-pregnant adults than ewes at 87-90 days of gestation. In WM, IL-1β was higher in ewes at 135-137 than 87-90 days of gestation, but IL-6 did not differ. Forty-eight and 72h after ischemia, CC IL-1β was higher than in non-ischemic fetuses. Seventy-two hours after ischemia, IL-1β and IL-6 were higher in WM than CC. In conclusion, IL-1β and IL-6 exhibit developmental regulation in fetal brain, change during gestation in brains of pregnant ewes, show regional differences in normal brains of fetuses and ewes, demonstrate differential responses after ischemia in CC and WM, and IL-1β but not IL-6 increases after ischemia in CC.

Cytokine profile and induction of T helper type 17 and regulatory T cells by human peripheral mononuclear cells after microbial exposure

The immunomodulatory effects of probiotics were assessed following exposure of normal peripheral blood mononuclear cells (PBMC), cord blood cells and the spleen-derived monocyte/macrophage cell line CRL-9850 to Lactobacillus acidophilus LAVRI-A1, Lb. rhamnosus GG, exopolysaccharides (EPS)-producing Streptococcus thermophilus St1275, Bifidobacteriun longum BL536, B. lactis B94 and Escherichia coli TG1 strains. The production of a panel of pro- and anti-inflammatory cytokines by PBMC following bacterial stimulation was measured, using live, heat-killed or mock gastrointestinal tract (GIT)-exposed bacteria, and results show that (i) all bacterial strains investigated induced significant secretion of pro- and anti-inflammatory cytokines from PBMC-derived monocytes/macrophages; and (ii) cytokine levels increased relative to the expansion of bacterial cell numbers over time for cells exposed to live cultures. Bifidobacteria and S. thermophilus stimulated significant concentrations of transforming growth factor (TGF)-β, an interleukin necessary for the differentiation of regulatory T cells (T(reg) )/T helper type 17 (Th17) cells and, as such, the study further examined the induction of Th17 and T(reg) cells after PBMC exposure to selected bacteria for 96 h. Data show a significant increase in the numbers of both cell types in the exposed populations, measured by cell surface marker expression and by cytokine production. Probiotics have been shown to induce cytokines from a range of immune cells following ingestion of these organisms. These studies suggest that probiotics' interaction with immune-competent cells produces a cytokine milieu, exerting immunomodulatory effects on local effector cells, as well as potently inducing differentiation of Th17 and T(reg) cells.

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.

Effects of acupuncture on Th1, th2 cytokines in rats of implantation failure

The aim is to explore the effect of acupuncture on Th1, Th2 cytokines in rats of implantation failure. Early pregnant rats were randomized into normal group (N), implantation failure group (M), acupuncture group (A), progestin group (H). The model was established with mifepristone. Samples of serum, endometrium were collected on Day 5, 6 and 8 of pregnancy. Compared with group M, the number of embryos was significantly higher in groups N, A and H; IL-1β, IL-2 protein in serum and endometrium were significantly lower in groups N, A and H, while IL-4, IL-10 were significantly higher in groups N, A and H; the endometrial IL-2, IL-4 mRNA were significantly lower in groups N, A and H, while IL-1β, IL-10 mRNA were significantly higher in groups N, A and H. Acupuncture could improve the poor receptive state of endometrium due to mifepristone by promoting Th2 cytokines secretion and inhibiting Th1 cytokines to improve blastocyst implantation.

[The role of infection in preterm birth]

Intrauterine infection could be responsible for 25% up to 40% of preterm births. This relationship was initially demonstrated using animal models, inducing their abortion by injecting bacteria or endotoxins. In human research, examination of amniocentesis fluid showed the anteriority of infection over labor induction, and the existence of a subclinical latency phase between these two phenomena. The ascending route is preponderant, and four stages can be distinguished: cervical and vaginal infection, chorio-decidual infection, intra-amniotic infection, fetal infection. The intrauterine infection is very frequent in case of early preterm birth (<30 WG). It is associated with an increase of neurological and pulmonary morbidity. Most commonly found bacterial species are mycoplasma species, but also Escherichia coli, Gardnerella vaginalis and streptococcus B. Several markers of the infection have been studied: a maternal leukocytosis>15,000/mm(3) or a C-Reactive Protein (CRP)>20mg/l, an increase of fibronectin and/or IL-6 cervical, a short cervical length especially before 32 WG, a leukocytosis of the amniotic fluid, and/or high interleukin concentrations. The main marker used for the newborn is the CRP, but other markers can also be used for an early diagnosis of an infection, especially interleukin 6.

Calcitriol inhibits interleukin-10 expression in cultured human trophoblasts under normal and inflammatory conditions

Preeclampsia is associated with systemic inflammation and increased expression of placental Th1-cytokines. IL-10 and calcitriol inhibit proinflammatory cytokines expression in human placenta helping to fetal allograft toleration. Regulation of placental IL-10 by calcitriol and Th-1 cytokines has not yet been fully elucidated. Since it is believed that calcitriol promotes a shift from a Th1- to a Th2 profile, we hypothesized that it would stimulate IL-10 in a normal and an inflammatory scenario to conjointly restrain inflammation. Therefore, we investigated calcitriol effects upon IL-10 expression in cultured human trophoblasts obtained from normal (NT) and preeclamptic (PE) pregnancies. Similar studies in the presence of TNF-α (as an inflammatory stressor) were also performed. Calcitriol dose-dependently inhibited IL-10 expression in NT, PE and TNF-α-challenged trophoblasts (P<0.05). This effect was prevented by a vitamin D receptor (VDR) antagonist. IL-10 expression was significantly stimulated by TNF-α and IL-1β, inhibited by IFN-γ and was not affected by IL-6. Finally, calcitriol inhibited TNF-α and IL-1β stimulation upon IL-10. In summary, in cultured human trophoblasts, calcitriol down-regulates IL-10 expression under normal as well as under natural and experimental inflammatory conditions. This effect is mediated by the VDR and might involve direct inhibition of TNF-α. In view of these and previous results it seems that in placenta calcitriol suppresses both Th1- and Th2 cytokines while undertakes the anti-inflammatory effects of IL-10 by itself, since both factors exert this task redundantly. The regulation of IL-10 by IFN-γ suggests that this cytokine could be a viable candidate to explain low IL-10 levels in preeclampsia.

Regulatory T helper cells in pregnancy and their roles in systemic versus local immune tolerance

PROBLEM

During pregnancy, the maternal immune system needs to adapt in order not to reject the semi-allogenic fetus.

METHOD

In this review, we describe and discuss the role of regulatory T (Treg) cells in fetal tolerance.

RESULTS

Treg cells constitute a T helper lineage that is derived from thymus (natural Treg cells) or is induced in the periphery (induced Treg cells). Treg cells are enriched at the fetal-maternal interface, showing a suppressive phenotype. In contrast, Treg cells are not increased in the circulation of pregnant women, and the suppressive capacity is similar to that in non-pregnant women. However, aberrations in Treg frequencies and functions, both systemically and in the uterus, may be involved in the complications of pregnancy.

CONCLUSION

Treg cells seem to have distinguished roles locally versus systemically, based on their distribution and phenotype.

Uterine Regulatory T cells, IL-10 and hypertension

PROBLEM

Regulatory T cells (T(reg) ) are a vital immune cellular population at the maternal-fetal interface. They are likely to aid in immune tolerance by dampening the harmful effects of other immune cellular populations through cell-cell-mediated interactions as well as by producing IL-10 and TGF-β. In addition to the anti-inflammatory properties, IL-10 has emerged as an important vascular cytokine choreographing endovascular interactions and angiogenesis and regulates hypertension.

METHOD OF STUDY

Review of innovative concepts to understand the temporal role of T(regs) in both mouse and human pregnancy, particularly whether uterine T(reg) play a potential role in regulating vascular homeostasis and blood flow during pregnancy.

RESULTS

T(reg) guard immune tolerance, getting cytotoxically activated under certain conditions, leading to adverse pregnancy outcome.

CONCLUSION

Despite increasing evidence of T(reg) tissue-specific expansion and functional plasticity, their role in vascular activity, pre-eclampsia or gestational diabetes is obscure and needs closer investigation to delineate its role later during pregnancy.

Macrophages at the fetal-maternal interface express markers of alternative activation and are induced by M-CSF and IL-10

During pregnancy, the maternal immune system is challenged by the presence of the fetus, which must be tolerated despite being semiallogeneic. Uterine mucosal (or decidual) macrophages (M), one of the major leukocyte populations at the fetal-maternal interface, have been implicated in fetal tolerance, but information regarding their regulation is scarce. In this study, we investigated the role of several factors potentially involved in the differentiation and polarization of decidual M with an in vitro M differentiation model. By using flow cytometry, we showed that M-CSF and IL-10 were potent inducers of M2 (immunoregulatory) M markers expressed on human decidual M (CD14, CD163, CD206, CD209). In contrast, proinflammatory stimuli, and unexpectedly also the Th2-associated IL-4 and IL-13, induced different patterns of expression, indicating that a Th2-dominated environment is not required for decidual M polarization. M-CSF/IL-10-stimulated and decidual M also showed similar cytokine secretion patterns, with production of IL-10 as well as IL-6, TNF, and CCL4. Conversely, the proinflammatory, LPS/IFN-γ-stimulated M produced significantly higher levels of TNF and no IL-10. We also used a gene array with 420 M-related genes, of which 100 were previously reported to be regulated in a global gene expression profiling of decidual M, confirming that M-CSF/IL-10-induced M are closely related to decidual M. Taken together, our results consistently point to a central role for M-CSF and in particular IL-10 in the shaping of decidual M with regulatory properties. These cytokines may therefore play an important role in supporting the homeostatic and tolerant immune milieu required for a successful pregnancy.

Placental immunology and maternal alloimmune responses

During pregnancy, women are tolerant of their semi-allogeneic fetus whilst not being immunosuppressed and indeed readily form alloantibodies. This 'Immunological Paradox of Pregnancy' may be explained by an understanding of placental anatomy and immunology. Trophoblast cells form the interface between the fetus and maternal tissues and blood and escape allorecognition because they lack classical human leucocyte antigen (HLA) class I and II molecules. Local immunoregulation, or tolerance, in the decidua is mediated partly by HLA-G(+) extravillous trophoblasts (EVT) that invade the tissue and prevent killing by maternal natural killer cells, cytotoxic T cells and macrophages. Placental hormones orchestrate the composition and regulatory function of maternal immune cells. In contrast, syncytiotrophoblast cells at the surface of chorionic villi, in contact with maternal blood, maintain a state of mild maternal systemic immunity via activation of innate immunity and skewing towards humoral immunity. This enables maintenance of a healthy immune system in pregnant women and robust protective antibody responses to pathogens whilst enabling survival of the fetus. However, this has the unfortunate consequence that pregnant women readily form alloantibodies to incompatible alloantigens on fetal red cells, platelets and leucocytes if fetomaternal haemorrhage (FMH) occurs. The antibodies are initially low affinity but after re-immunization with further FMH become functionally effective, high-titre IgG.

Haplotype-dependent differential activation of the human IL-10 gene promoter in macrophages and trophoblasts: implications for placental IL-10 deficiency and pregnancy complications

PROBLEM

polymorphic changes in the IL-10 gene promoter have been identified that lead to altered IL-10 production. We hypothesized that because of these genotypic changes, the IL-10 promoter might be expressed in a cell type-specific manner and may respond differentially to inflammatory triggers.

METHOD OF STUDY

we created reporter gene promoter constructs containing GCC, ACC, and ATA haplotypes using DNA from patients harboring polymorphic changes at -1082 (G→A), -819 (C→T), and -592 (C→A) sites in the IL-10 promoter. These individual luciferase reporter constructs were transiently transfected into either primary term trophoblasts or THP1 monocytic cells. DNA-binding studies were performed to implicate the role of the Sp1 transcription factor in response to differential promoter activity.

RESULTS

our results suggest that the GCC promoter construct was activated in trophoblast cells in response to lipopolysaccharide (LPS), as demonstrated by reporter gene expression, but not in monocytic cells. The ACC construct showed weaker activation in both cell types. Importantly, while the ATA promoter was constitutively activated in both cell types, its expression was selectively repressed in response to LPS, but only in trophoblasts. DNA-nuclear protein binding assays with nuclear extracts from LPS treated or untreated cells suggested a functional relevance for Sp1 binding differences at the -592 position.

CONCLUSIONS

these results demonstrate cell type-specific effects of the genotypic changes in the IL-10 gene promoter. These responses may be further modulated by bacterial infections or other inflammatory conditions to suppress IL-10 production in human trophoblasts.

Vascular IL-10: a protective role in preeclampsia

IL-10 is a pregnancy compatible cytokine that plays a vital role in maintaining the balance of anti-inflammatory and pro-inflammatory milieu at the maternal-fetal interface. Recent evidence now suggests that IL-10 is a potent vascular cytokine that can blunt hypertension and inflammation-mediated vascular dysfunction. Thus, a re-evaluation of IL-10 as a cytokine supporting endovascular interactions and angiogenesis as well as blunting hypoxic-injury and preeclampsia-like features is warranted. In this review, we highlight these novel functions of IL-10 and propose that its immune-modulating and vascular functions are mutually inclusive, particularly in the context of normal gestation.

Review: hCG, preeclampsia and regulatory T cells

Human chorionic gonadotropin (hCG) is crucial for successful pregnancy. Its many functions include angiogenesis and immune regulation. Despite years of research, the etiology of preeclampsia remains unknown. Marked by insufficient trophoblast invasion and poor spiral artery remodeling, preeclampsia has also been linked to immune dysregulation. Here we discuss the roles of hCG in the context of endovascular cross-talk between trophoblasts and endothelial cells and immune tolerance. We propose that functional and glycosylation modifications of hCG may contribute to the pathogenesis of preeclampsia.

A critical role of interleukin-10 in modulating hypoxia-induced preeclampsia-like disease in mice

Hypoxia has been implicated in the pathogenesis of preeclampsia, a hypertensive disorder of pregnancy. However, in vivo evidence and mechanistic understanding remain elusive. Preeclampsia is associated with impaired placental angiogenesis. We have recently shown that interleukin (IL)-10 can support trophoblast-driven endovascular crosstalk. Accordingly, we hypothesize that pathological levels of oxygen coupled with IL-10 deficiency induce severe preeclampsia-like features coupled with elevated production of antiangiogenic factors, apoptotic pathways, and placental injury. Exposure of pregnant wild-type and IL-10(-/-) mice to 9.5% oxygen resulted in graded placental injury and systemic symptoms of renal pathology, proteinuria (wild-type 645.15 ± 115.73 versus 198.09 ± 93.45; IL-10(-/-) 819.31 ± 127.85 versus 221.45 ± 82.73 μg/mg/24 hours) and hypertension (wild-type 118.37 ± 14.45 versus 78.67 ± 14.07; IL-10(-/-) 136.03 ± 22.59 versus 83.97 ± 18.25 mm Hg). Recombinant IL-10 reversed hypoxia-induced features in pregnant IL-10(-/-) mice confirming the protective role of IL-10 in preeclampsia. Hypoxic exposure caused marked elevation of soluble fms-like tyrosine kinase 1 (110.8 ± 20.1 versus 44.7 ± 11.9 ng/mL) in IL-10(-/-) mice compared with their wild-type counterparts (81.6 ± 13.1 versus 41.2 ± 8.9 ng/mL), whereas soluble endoglin was induced to similar levels in both strains (approximately 380 ± 50 versus 180 ± 31 ng/mL). Hypoxia-induced elevation of p53 was associated with marked induction of proapoptotic protein Bax, downregulation of Bcl-2, and trophoblast-specific apoptosis in utero-placental tissue. Collectively, we conclude that severe preeclampsia pathology could be triggered under certain threshold oxygen levels coupled with intrinsic IL-10 deficiency, which lead to excessive activation of antiangiogenic and apoptotic pathways.

Maternal serum levels of TNF-alpha and IL-6 long after delivery in preeclamptic and normotensive pregnant women

AIM

To evaluate maternal TNF-alpha and IL-6 plasma levels in normotensive pregnant women, women with preeclampsia, and to examine the temporal changes in their levels from the antepartum to the postpartum period correlated with the regression of preeclampsia.

METHOD

A prospective study was performed in the 2nd Department of Obstetrics and Gynecology, University of Athens. Blood samples were obtained: (1) antepartum at the time of clinical diagnosis of the syndrome, 2. 12-14 weeks postpartum.

RESULTS

No statistically significant differences were found in IL-6 levels, whereas a difference was found in TNF-alpha levels between preeclamptic and controls in antepartum period (0.80 pg/ml versus 0.60 pg/ml, P : .04). Long after delivery, TNF-alpha levels were significantly higher in preeclamptic compared to normotensive controls (0.86 pg/ml versus 0.60 pg/ml, P : .004). No difference was observed in TNF-alpha before and after delivery in both groups. No difference was noticed in IL-6 levels in women of normotensive group long after delivery compared to that before delivery. Long after delivery IL-6 levels were statistically significant higher in preeclamptic women compared to normal controls (3.53 ± 0.52 pg/ml versus 1.69 ± 0.48 pg/ml, P : .02).

CONCLUSION

Preeclamptic women remain under a status of increased inflammatory stress up to 12-14 weeks postpartum despite the fact that all the other signs of preeclampsia are resolved.

Maternal Schistosomiasis japonica is associated with maternal, placental, and fetal inflammation

Schistosomes infect ∼40 million women of childbearing age and result in the elaboration of proinflammatory cytokines that have been implicated in fetal growth restriction. In murine models and two observational studies in humans, schistosome infection during pregnancy was associated with reduced birth weight, although a recent treatment trial in Schistosoma mansoni did not detect this association. We conducted an observational study among 99 pregnant women living in an area of Schistosoma japonicum endemicity in the Philippines. We enrolled women at 32 weeks gestation and measured S. japonicum and geohelminth infection intensity. We collected maternal peripheral blood at 32 weeks gestation and placental and cord blood at delivery to assess inflammatory status. At delivery, we collected a placental-tissue sample and measured birth weight. In multivariate models adjusted for geohelminths, maternal schistosomiasis was associated with increased levels of inflammatory cytokines in maternal peripheral (tumor necrosis factor alpha [TNF-α] and interleukin 10 [IL-10]), placental (TNF-α, IL-6, TNF-α receptor II [RII], and IL-1β), and cord (IL-1β and TNF-α RII) blood, as well as acute subchorionitis and increased TNF-α production by syncytiotrophoblasts assessed by immunohistochemistry (all P < 0.05). After adjusting for confounders, placental IL-1β, and TNF-α production by syncytiotrophoblasts was independently associated with decreased birth weight (both P < 0.05). Our data indicate that maternal schistosomiasis results in a proinflammatory signature that is detectable in maternal, placental, and fetal compartments, and a subset of these responses are associated with decreased birth weight. This potential mechanistic link between maternal schistosomiasis and poor birth outcomes will contribute to the debate regarding treatment of maternal schistosome infections.

Low maternal serum matrix metalloproteinase (MMP)-2 concentrations are associated with preterm labor and fetal inflammatory response

OBJECTIVES

to assess the relationship between maternal and umbilical serum concentrations of matrix metalloproteinases (MMP)-2,8,9, the soluble receptor for advanced glycation end products (sRAGE) and IL-10 and premature delivery and fetal inflammation.

METHODS

maternal serum levels of MMPs, sRAGE, IL-10 and C-reactive protein (CRP) were determined in 67 women with preterm labor and in 38 healthy pregnant women of similar gestational age (GA). In the group with preterm labor we also determined umbilical concentrations of MMPs, IL-6 and sRAGE. The group with preterm labor was additionally divided based on the presence of funisitis and elevations of fetal umbilical IL-6 concentrations.

RESULTS

maternal serum levels of MMP-2 and sRAGE were significantly lower in women with preterm labor compared to women with normal pregnancy. Additionally, within the group of women with preterm labor, maternal serum MMP-2 concentrations were significantly lower in the subgroup with funisitis and in the subgroup with elevated umbilical concentration of IL-6.

CONCLUSION

our results demonstrate significantly different serum concentrations of MMP-2 and sRAGE in women with preterm labor compared to healthy pregnant patients of the same GA.

Sera from preeclampsia patients elicit symptoms of human disease in mice and provide a basis for an in vitro predictive assay

Early diagnosis and treatment of preeclampsia would significantly reduce maternal and fetal morbidity and mortality. However, its etiology and prediction have remained elusive. Based on the hypothesis that sera from patients with preeclampsia could function as a "blueprint" of causative factors, we describe a serum-based pregnancy-specific mouse model that closely mirrors the human condition as well as an in vitro predictive assay. We show that a single administration of human preeclampsia serum in pregnant IL-10-/- mice induced the full spectrum of preeclampsia-like symptoms, caused hypoxic injury in uteroplacental tissues, and elevated soluble fms-like tyrosine kinase 1 and soluble endoglin, markers thought to be related to the disease. The same serum sample(s) induced a partial preeclampsia phenotype in wild-type mice. Importantly, preeclampsia serum disrupted cross talk between trophoblasts and endothelial cells in an in vitro model of endovascular activity. Disruption of endovascular activity could be documented in serum samples as early as 12 to 14 weeks of gestation from patients who subsequently developed preeclampsia. These results indicate that preeclampsia patient sera can be used to understand the pregnancy-specific disease pathology in mice and can predict the disorder.

Identification of a novel role for endothelins within the oviduct

Endothelins were first identified as potent vasoactive peptides; however, diversity in the biological function of these hormones is now evident. We have identified a novel role for endothelins: a requirement for these peptides within the oviduct during fertilization and/or early embryo development. In vivo, treatment after ovulation with a dual endothelin receptor antagonist (tezosentan) decreased the number of two-cell embryos that could be collected from within the oviducts. In vitro fertilization experiments showed that gamete viability and their ability to fertilize were not affected by treatment with this antagonist, suggesting that the effect observed in vivo was mediated by the oviduct itself. Expression of mRNA for all three isoforms of the endothelins and both receptor subtypes was detectable within the oviduct. Expression of mRNA for endothelin-3 was regulated by gonadotropins in epithelial cells of the oviduct and increased specifically within the isthmus of this structure. Immunostaining revealed localization of both endothelin receptors A and B to the columnar epithelial cells within the oviduct, suggestive of a local role for endothelins in the regulation of epithelial function and ultimately oviductal secretions. A microarray analysis revealed three likely endothelin-regulated protein networks for future analysis: the TGFbeta, IL-10, and CCAAT/enhancer-binding protein superfamilies. Overall, these results suggest a novel and requisite role for endothelins within the oviduct during fertilization and/or early embryo development.

Beyond the threshold: an etiological bridge between hypoxia and immunity in preeclampsia

Taking a cue from the recent workshop 'Preeclampsia--a Pressing Problem' sponsored by the National Institutes of Child Health and Human Development, this review article takes a fresh look at hypoxia and a dysfunctional immune system as the key contributors to the etiology of preeclampsia and the mechanisms involved therein. In the context of epidemiological research on the intricate and multifactorial nature of preeclampsia, we focus on hypoxia as an upstream regulator of preeclampsia and its consequences in a model compromised by a deficiency in key pregnancy compatible immune modulators. It has been proposed that placental hypoxia releases cytotoxic factors produced at the maternal-fetal interface into the circulation to manifest the maternal symptoms associated with preeclampsia. However, it is not clear how this mechanism is empowered in pregnant women. Does systemic hypoxia exert preeclampsia-like effects on pregnancy? Are these effects further manifested by intrinsic inflammation in the absence of key immune modulators such as IL-10? Thus, it is of paramount importance that in vivo models be developed wherein the role of systemic hypoxia can be evaluated for preeclampsia-causing events. We present a discussion on whether prolonged exposure to hypoxia can lead to a perpetual cycle of compartmentalized uteroplacental tissue damage, release of anti-angiogenic and vasoconstrictive factors that impair trophoblast invasion and promote systemic vascular resistance resulting in the maternal syndrome.

Environmental levels of para-nonylphenol are able to affect cytokine secretion in human placenta

BACKGROUND

para-Nonylphenol (p-NP) is a metabolite of alkylphenols widely used in the chemical industry and manufacturing. It accumulates in the environment, where it acts with estrogen-like activity. We previously showed that p-NP acts on human placenta by inducing trophoblast differentiation and apoptosis.

OBJECTIVE

The aim of the present study was to investigate the effect of p-NP on cytokine secretion in human placenta.

METHODS

In vitro cultures of chorionic villous explants from human placenta in the first trimester of pregnancy were treated with p-NP (10(13), 10(11), and 10(9) M) in 0.1% ethanol as vehicle. Culture medium was collected after 24 hr and assayed by specific immunoassays for the cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-gamma), interleukin (IL)-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, and tumor necrosis factor-alpha (TNF-alpha).

RESULTS

p-NP modulated cytokine secretion by inducing the release of GM-CSF, IFN-gamma, IL-1beta, IL-4, and IL-10, with a maximum effect at 10(11) M. It reduced the release of TNF-alpha at 10(13) M, whereas levels of IL-2 and IL-5 remained below the detection limit. IL-6 and IL-8 levels were 1001,000 times higher than those of other cytokines, and they were not affected by p-NP. We observed significant differences from controls (ethanol alone) only for GM-CSF and IL-10.

CONCLUSION

An unbalanced cytokine network at the maternal--fetal interface may result in implantation failure, pregnancy loss, or other complications. The effects of extremely low doses of p-NP on the placental release of cytokines raise considerable concerns about maternal exposure to this endocrine disruptor during pregnancy.

Interleukin-10: a multi-faceted agent of pregnancy

It is widely accepted that pregnancy constitutes a unique developmental event. Unprecedented intrauterine actions of angiogenesis, immunity, and neuroendocrine regulation are juxtaposed to mechanisms of senescence that enable fetal growth and protection. The suppressive and regulatory factors that facilitate healthy pregnancy are under investigation. In non-pregnant systems of infection and inflammation, the cytokine interleukin-10 (IL-10) has been widely investigated because of its potential as a key immunosuppressant in response to a multitude of inflammatory events. In the context of pregnancy, IL-10 levels increase markedly in women during early pregnancy and remain elevated well into the third trimester immediately prior to onset of labor. The role of IL-10 during pregnancy as a suppressor of active maternal immunity to allow acceptance of the fetal allograft has been a point of study. Moreover, secretion of IL-10 by a diverse set of maternal and fetal cells has proven to aid in the orchestration of normal processes of pregnancy. Interestingly, some of the more profound findings regarding the actions of IL-10 during pregnancy have manifested from research that focuses on aberrant pregnancy outcomes as a result of inflammation, hormonal imbalances, or gene-environment interactions. This review focuses on the role of IL-10 as a facilitator of successful pregnancy both as an immune suppressive agent and a mediator of cross talk between the placenta and the decidua. Importantly, we discuss investigations on adverse pregnancy conditions to further elucidate the multifarious role of IL-10 at the maternal-fetal interface.

The transcriptome of the fetal inflammatory response syndrome

PROBLEM

The fetal inflammatory response syndrome (FIRS) is considered the counterpart of the systemic inflammatory response syndrome (SIRS), but similarities in their regulatory mechanisms are unclear. This study characterizes the fetal mRNA transcriptome of peripheral leukocytes to identify key biological processes and pathways involved in FIRS.

METHOD OF STUDY

Umbilical cord blood from preterm neonates with FIRS (funisitis, plasma IL-6 >11 pg/mL; n = 10) and neonates with no evidence of inflammation (n = 10) was collected at birth. Results Microarray analysis of leukocyte RNA revealed differential expression of 541 unique genes, changes confirmed by qRT-PCR for 41 or 44 genes tested. Similar to SIRS and sepsis, ontological and pathway analyses yielded significant enrichment of biological processes including antigen processing and presentation, immune response, and processes critical to cellular metabolism.

RESULTS

are comparable with microarray studies of endotoxin challenge models and pediatric sepsis, identifying 25 genes across all studies.

CONCLUSION

This study is the first to profile genome-wide expression in FIRS, which demonstrates a substantial degree of similarity with SIRS despite differences in fetal and adult immune systems.

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.

IL-10 modulates placental responses to TLR ligands

PROBLEM

Intra-uterine infections increase production of pro-inflammatory cytokines. It is unclear whether different infectious agents determine the relative expression of pro-and anti-inflammatory cytokines.

METHODS OF STUDY

We compared the placental inflammatory response induced by bacterial lipopolysaccharide (LPS, endotoxin from Gram-negative bacteria) with those induced by lipoteichoic acid (LTA, a cell wall component of Gram-positive bacteria). Placental explants from term delivery were treated with either LPS or LTA, in the presence or absence of IL-10, for 24 hrs. Cytokines, prostaglandin E(2) (PGE(2)) production and cyclo-oxygenase-2 (COX-2) expression were quantified.

RESULTS

Both LTA and LPS significantly induced several cytokines with LPS eliciting more potent effects. IL-6 and IL-8 were induced to comparable levels in response to both LTA and LPS whereas monocyte chemotactic protein-1 (MCP-1) production was induced more by LTA, demonstrating a differential placental response to a specific toll-like receptor (TLR) ligand. IL-10 treatment significantly reduced most pro-inflammatory cytokines as well as PGE(2) induced by both LPS and LTA. Interestingly, IL-10 down-regulated LTA-mediated MCP1 induction, but not that mediated by LPS. Moreover, IL-10 was more effective in down-regulating PGE(2) after LPS- when compared with LTA stimulation.

CONCLUSIONS

Our results demonstrate that placental exposure to LTA and LPS appear to trigger distinct cytokine responses that can be modulated by IL-10.

Placental IL-10 dysregulation and association with bronchopulmonary dysplasia risk

Cytokine profiles in amniotic fluid, cord serum, and tracheal aspirate of premature infants suggest a shift toward a proinflammatory state. Cytokines also contribute to the pathogenesis of bronchopulmonary dysplasia (BPD). We hypothesize that the initiating events for BPD are reflected in the placenta and propose that placental expression of cytokines provide a blueprint of events leading to BPD. This is a retrospective, case-controlled study of placental cytokines of premature infants with (n = 49) and without (n = 49) BPD, matched for gender, birth weight, and year of birth at Women and Infants Hospital between 2003 and 2005. Cytokine expression, including IL-6 and IL-10, was determined by immunohistochemistry in membrane rolls, umbilical cords, and placentas. IL-6 was similarly expressed in all tissues of infants with and without BPD. In contrast, anti-inflammatory cytokine IL-10 was less prominent in the placenta of patients with BPD compared with those without BPD. IL-10 expression in the villous trophoblast layer was associated with a reduced odds ratio of developing BPD (adjusted OR 0.08, 95% CI 0.01-0.70, p = 0.02). These results suggest that a placental balance between inflammatory and anti-inflammatory cytokines is crucial to normal lung organogenesis. Importantly, IL-10 seems to be protective against the development of BPD.

Inflammatory pathways in female reproductive health and disease

Inflammation involves alterations to vascular and immune cell function. It is well recognised that many physiological reproductive events such as ovulation, menstruation, implantation and onset of labour display hallmark signs of inflammation. These are orchestrated by specific molecular pathways involving a host of growth factors, cytokines, chemokines and lipid mediators. Resumption of normal reproductive function involves prompt and proper resolution of these inflammatory pathways. Recent literature confirms that resolution of inflammatory pathways involves specific biochemical events that are activated to re-establish homeostasis in the affected tissue. Moreover, initiation and maintenance of inflammatory pathways are the key components of many pathologies of the reproductive tract and elsewhere in the body. The onset of reproductive disorders or disease may be the result of exacerbated activation and maintenance of inflammatory pathways or their dysregulated resolution. This review will address the role of inflammatory events in normal reproductive function and its pathologies.

The isolation and characterization of a novel telomerase immortalized first trimester trophoblast cell line, Swan 71

Studies using first trimester trophoblast cells may be limited by the inability to obtain patient samples and/or adequate cell numbers. First trimester trophoblast cell lines have been generated by SV40 transformation or similar methods, however, this approach is known to induce phenotypic and karyotypic abnormalities. The introduction of telomerase has been proposed to be a viable alternative for the immortalization of primary human cells. To investigate whether telomerase-induced immortalization might be a more feasible approach for the generation of first trimester trophoblast cell lines, we isolated primary trophoblast cells from a 7-week normal placenta and infected the cells with human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase. Although this hTERT-infected first trimester trophoblast cell line, which we have named Swan 71, has been propagated for more than 100 passages, it still has attributes that are characteristic of primary first trimester trophoblast cells. The Swan 71 cells are positive for the expression of cytokeratin 7, vimentin and HLA-G, but do not express CD45, CD68 or the Fibroblast Specific Antigen (FSA), CD90/Thy-1. In addition, we also demonstrated that the Swan 71 cells secrete fetal fibronectin (FFN) as well as low levels of human Chorionic Gonadotrophin (hCG). Moreover, the Swan 71 cells exhibit a cytokine and growth factor profile that is similar to primary trophoblast cells and are resistant to Fas, but not TNF-alpha-induced apoptosis. This suggests that the Swan 71 cells may represent a valuable model for future in vitro trophoblast studies.

Progesterone-induced blocking factor and cytokine profile in women with threatened pre-term delivery

PROBLEM

The objective of this study was to compare serum concentrations of progesterone-induced blocking factor (PIBF), anti-inflammatory (IL-10),and pro-inflammatory (IL-6, TNFa, and IFNc) cytokines of women with threatened pre-term delivery, with those of women with normal pregnancy and to evaluate the impact of PIBF on the outcome of pregnancy.

METHOD OF STUDY

A prospective study was conducted on a sample of 30 women with threatened pre-term delivery (study group) and 20 healthy pregnant women (control group) between the 24th and 37th gestational weeks. Serum PIBF, anti-inflammatory (IL-10), and pro-inflammatory (IL-6, TNFa, and IFNc) cytokine concentrations were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Thirteen of 30 patients (43.3%) with symptoms of threatened pre-term delivery, and one of 20 patients (5%) in the control group delivered before the 37th week of gestation. Mean PIBF concentrations in serum samples of patients with threatened pre-term delivery were significantly lower than in those of healthy pregnant women (171.12 +/-162.06 ng/mL versus 272.85 +/- 114.87 ng/mL; P < 0.05).Women with symptoms of threatened pre-term delivery had significantly lower serum levels of IL-10, and higher levels of IL-6 as well as IFNc compared with healthy controls.

CONCLUSION

Our results indicate that measuring PIBF and cytokine concentrations in serum during pregnancy is feasible and may be important for understanding immunological causes of pre-term delivery.

The water channel aquaporin 1 is a novel molecular target of polychlorinated biphenyls for in utero anomalies

Despite serious health risks in humans and wild life, the underlying mechanisms that explain the gene-environment effects of chemical toxicants are largely unknown. Polychlorinated biphenyls (PCBs) are one of the most ubiquitous environmental toxicants worldwide, with reported epidemiological evidence for reproductive and neurocognitive anomalies in humans. Here, we show that Aroclor 1254, a mixture of structurally distinct PCBs, causes preterm birth in interleukin (IL)-10(-/-) mice at a dose that does not show any adverse effects in wild type mice, highlighting the significance of IL-10 as an anti-toxicant cytokine. Aroclor 1254-treated IL-10(-/-) mice demonstrated increased amniotic fluid, intrauterine growth restriction, and reduced litter size with postnatal neuromotor defects. Further, our results identify aquaporin 1 (AQP1), a potent effector of fluid volume regulation and angiogenic activity, as a novel placental target of PCBs. In vivo or in vitro exposure to Aroclor 1254 coupled with IL-10 deficiency significantly reduced the protein content of AQP1. Reduced uterine AQP1 levels were associated with defective spiral artery transformation. Importantly, recombinant IL-10 reversed PCB-induced in vivo and in vitro effects. These data demonstrate for the first time that the IL-10-AQP1 axis is a novel regulator of PCB-induced in utero effects.

Evidence for participation of uterine natural killer cells in the mechanisms responsible for spontaneous preterm labor and delivery

OBJECTIVE

The purpose of this study was to determine in a mouse model whether uterine natural killer (uNK) cell cytotoxic activation induces infection/inflammation-associated preterm labor and delivery.

STUDY DESIGN

Wild type or interleukin (IL)-10(-/-) mice were injected intraperitoneally with lipopolysaccharide on gestational day 14. Mice were either killed for collection of uteroplacental tissue, spleen, and serum or allowed to deliver. Uteroplacental tissue was used for histology and characterization of uNK cells.

RESULTS

Low-dose lipopolysaccharide treatment triggered preterm labor and delivery in IL-10(-/-), but not wild type mice, in a manner independent of progesterone levels. Preterm labor and delivery in IL-10(-/-) mice was associated with an increased number and placental infiltration of cytotoxic uNK cells and placental cell death. Depletion of NK cells or tumor necrosis factor (TNF)-alpha neutralization in these mice restored term delivery. Furthermore, TNF-alpha neutralization prevented uNK cell infiltration and placental cell apoptosis.

CONCLUSION

The uNK cell-TNF-alpha-IL-10 axis plays an important role in the genesis of infection/inflammation-induced preterm labor/delivery.

Interleukin 10 gene promoter polymorphisms in women with pregnancy loss: preferential association with embryonic wastage

Interleukin 10 (IL10) is associated with maternal immunotolerance. IL10 also down-regulates decidual cell tissue factor expression, the main molecule triggering coagulation activation: this antithrombotic effect may protect the umbilicoplacental vasculature from the 10th wk of gestation onward. IL10 down-regulation may thus dispose to early pregnancy loss (PL) due to maternal immunotolerance defect or late pregnancy failure due to placental vascular insufficiency. IL10 gene promoter polymorphisms associated with cytokine down-regulation may help to identify the actual and probable mechanisms of IL10 modulation in pregnancy outcomes. We investigated the following four IL10 promoter polymorphisms associated with IL10 down-regulation: two single-nucleotide polymorphisms rs1800871 and rs1800872 and two polymorphic CA repeat microsatellites IL10 X78437.2:g8134CA(14_29) and IL10 X78437.2:g.5325CA(11_15). Each microsatellite was analyzed as a biallelic polymorphism. Based on a review of the literature, we define a short allele and a long allele for each microsatellite. We compared their frequencies in early PL occurring before 10 wk of amenorrhea (n = 342) and in PL occurring later on (n = 123). The mutated alleles rs1800871T (odds ratio, 3.083; 95% confidence interval, 1.984-4.792) and rs1800872A (odds ratio, 3.013; 95% confidence interval, 1.924-4.719) were associated with early PL. The haplotype rs1800872A/rs1800871T/X78437.2:g.8134CA[14_25]/X78437.2:g.5325CA[11_13], which includes the two mutated alleles, was significantly associated with the risk of early PL in a dose-dependent manner. Positivity for one haplotype was significantly associated with a 5.6-fold increase in the risk of early pregnancy failure, and positivity for two haplotypes was associated with an 8-fold increase in risk. In women with PL, some polymorphisms of the IL10 gene promoter seem to be constitutional risk factors for early (embryonic) pregnancy failure.

IL-10-secreting T cells from HIV-infected pregnant women downregulate HIV-1 replication: effect enhanced by antiretroviral treatment

OBJECTIVE

This study aimed to evaluate the impact of pregnancy-related immune events on the HIV-1 replication and to analyze their relationship with the risk of vertical transmission.

METHODS

The peripheral blood from HIV-1-infected pregnant women who controlled (G1) or not controlled (G2) their plasma viral load was drawn, and the plasma and the T cells were obtained. The T-cell cultures were activated in vitro with anti-CD3 and anti-CD28, and the proliferation and cytokine production profile were evaluated after 3 days of incubation. The in-vitro HIV-1 replication was measured in culture supernatants in the seventh day following stimulation. The cytokines were also analyzed in the plasma.

RESULTS

Our results demonstrated a lower T-cell proliferation and a lower interleukin-1beta, tumor necrosis factor-alpha and interferon-gamma production in polyclonally activated T-cell cultures from G1 patients, when compared with G2. Furthermore, high levels of interleukin-10 were produced both systemically and by activated T-cell cultures from G1 patients. Interestingly, the neutralization of endogenous interleukin-10 by anti-interleukin-10 monoclonal antibody elevated both the inflammatory cytokines' release and the HIV-1 replication in the polyclonally activated T-cell cultures from G1 patients. Additionally, the maternal antiretroviral treatment significantly enhanced the systemic interleukin-10 production. Finally, the higher systemic interleukin-10 levels were inversely correlated with vertical virus transmission risk.

CONCLUSION

These results indicate that a high tendency of pregnant women to produce interleukin-10 can help them control the HIV-1 replication, and this can reduce the risk of vertical transmission. Furthermore, our data suggest a role for maternal antiretroviral treatment in enhancing this phenomenon.

Cytokine responses in very low birth weight infants receiving glutamine-enriched enteral nutrition

OBJECTIVE

Very low birth weight (VLBW) infants receiving glutamine-enriched enteral nutrition may present with a lower infection rate, which may result from enhanced antimicrobial innate or Th1 cytokine responses. We investigated whether glutamine-enriched enteral nutrition in VLBW infants increased these cytokine responses following in vitro stimulation of whole blood cells.

METHODS

In a double-blind, placebo-controlled, randomized controlled trial, VLBW infants (gestational age <32 weeks and/or birth weight <1500 g) received enteral glutamine supplementation (0.3 g x kg(-1) x day(-1)) or isonitrogenous placebo supplementation (alanine) between days 3 and 30 of life. Cytokine responses following in vitro whole blood cell stimulation with anti-(alpha)CD3/alphaCD28 or lipopolysaccharide were analyzed by cytometric bead array at 3 time points: before the start of the study, at day 7 of life, and at day 14 of life.

RESULTS

Baseline patient and nutritional characteristics were not different between groups. At least 2 blood samples were analyzed in 25 of 52 (48%) and 38 of 50 (76%) infants in the glutamine-supplemented and control groups, respectively. Glutamine-enriched enteral nutrition was not associated with significant alterations in cytokine responses (interferon-gamma, tumor necrosis factor-alpha, interleukin [IL]-2, IL-4, IL-5, and IL-10) of peripheral blood cells upon stimulation with either anti-alphaCD3/alphaCD28 or lipopolysaccharide.

CONCLUSIONS

We hypothesize that glutamine-enriched enteral nutrition decreases the infection rate in VLBW infants by influencing the mucosal and not the systemic immune system.

Recurrent miscarriages: What is the role of cytokines?

Recurrent miscarriage is defined as three or more consecutive miscarriages before 20 weeks of gestation. This condition is a frequent reproductive problem worldwide, affecting up to 1% of couples. Immune effector cell dysfunction has been implicated in the pathogenesis of early pregnancy loss. This dysfunction may involve defects in cytokines, growth factors and immunosuppressive factors at the maternofetal interface. This is a growing research field, especially the role of cytokines in recurrent miscarriage.