Regulation of FasL/Fas in human trophoblasts: possible implications for chorioamnionitis

Plasma IGFBP-1, Fas, kallistatin, and P-selectin as predictive biomarkers of histologic chorioamnionitis and associated intra-amniotic infection in women with preterm labor

PROBLEM

To determine whether altered levels of 13 plasma biomarkers, alone or in combination, could be independently associated with histologic chorioamnionitis (HCA) and microbial-associated HCA (defined as the presence of HCA along with microbial invasion) in women with preterm labor (PTL).

METHODS OF STUDY

This was a retrospective cohort study involving 77 singleton pregnant women with PTL (23-34 gestational weeks) who delivered within 96 h of plasma and amniotic fluid (AF) sampling. DKK-3, E-selectin, Fas, haptoglobin, IGFBP-1, kallistatin, MMP-2, MMP-8, pentraxin 3, progranulin, P-selectin, SAA4, and TGFBI levels were assayed in plasma samples by ELISA. AF obtained via amniocentesis was used for microorganism identification.

RESULTS

Multiple logistic regression analyses revealed significant associations between low plasma IGFBP-1 levels and acute HCA, and between low plasma Fas and kallistatin levels, and elevated plasma P-selectin levels and microbial-associated HCA (all p < .05), after adjusting for gestational age. Using a stepwise regression procedure, a multi-biomarker panel for microbial-associated HCA was developed, which included plasma MMP-2, kallistatin, and P-selectin levels (area under the curve [AUC], .867). The AUC for this three-marker panel was significantly or borderline significantly greater than that of any single variable included in the panel. However, a predictive model for acute HCA could not be developed because only one variable (MMP-2) was selected.

CONCLUSIONS

These findings demonstrate that IGFBP-1, Fas, kallistatin, and P-selectin are associated with acute HCA and microbial-associated HCA in women with PTL. Their combined use can significantly improve the diagnostic ability for the detection of microbial-associated HCA.

Immunobiology of Acute Chorioamnionitis

Acute chorioamnionitis is characterized by neutrophilic infiltration and inflammation at the maternal fetal interface. It is a relatively common complication of pregnancy and can have devastating consequences including preterm labor, maternal infections, fetal infection/inflammation, fetal lung, brain, and gastrointestinal tract injury. In this review, we will discuss current understanding of the pathogenesis, immunobiology, and mechanisms of this condition. Most commonly, acute chorioamnionitis is a result of ascending infection with relatively low-virulence organisms such as the Ureaplasma species. Furthermore, recent vaginal microbiome studies suggest that there is a link between vaginal dysbiosis, vaginal inflammation, and ascending infection. Although less common, microorganisms invading the maternal-fetal interface via hematogenous route (e.g., Zika virus, Cytomegalovirus, and Listeria) can cause placental villitis and severe fetal inflammation and injury. We will provide an overview of the knowledge gleaned from different animal models of acute chorioamnionitis and the role of different immune cells in different maternal-fetal compartments. Lastly, we will discuss how infectious agents can break the maternal tolerance of fetal allograft during pregnancy and highlight the novel future therapeutic approaches.

Rosiglitazone blocks first trimester in-vitro placental injury caused by NF-κB-mediated inflammation

Increased inflammation and abnormal placentation are common features of a wide spectrum of pregnancy-related disorders such as intra uterine growth restriction, preeclampsia and preterm birth. The inflammatory response of the human placenta has been mostly investigated in relation to cytokine release, but the direct molecular consequences on trophoblast differentiation have not been investigated. This study measured the general effects of LPS on both extravillous and villous trophoblast physiology, and the involvement of the transcription factors PPARγ and NF-κB, specifically using 1^st trimester explants and HTR-8/ SVneo cell line models. While both proteins are known for their roles in inflammatory pathways, PPARγ has been identified as an important molecule in trophoblast differentiation, suggesting its potential role in mediating a crosstalk between inflammation and trophoblast differentiation. Here, LPS (1 µg/ml) exposure of first trimester placental villous explants resulted in secretion of inflammatory cytokines, induction of apoptosis and reduction in trophoblast cell proliferation. Additionally, LPS significantly reduced expression of the trophoblast differentiation proteins GCM1 and β-hCG, and increased invasion of the extravillous trophoblast. Activation of PPARγ by Rosiglitazone (10 µM) reversed the LPS-mediated effects on inflammatory cytokine release, trophoblast apoptosis and proliferation compared to controls. Lastly, markers of trophoblast differentiation and invasion reverted to control levels upon activation of PPARγ and concomitant inhibition of NF-κB (either by Rosiglitazone or NF-κB specific inhibitor), revealing a new role for NF-κB in trophoblast invasion. This study reveals a novel PPARγ - NF-κB axis that coordinates inflammatory and differentiation pathways in the human placenta. The ability to reverse trophoblast-associated inflammation with Rosiglitazone offers promise that the PPARγ - NF-κB pathway could one day provide a therapeutic target for placental dysfunction associated with both inflammation and abnormal trophoblast differentiation.

Interferon-Gamma and Fas Are Involved in Porphyromonas gingivalis-Induced Apoptosis of Human Extravillous Trophoblast-Derived HTR8/SVneo Cells via Extracellular Signal-Regulated Kinase 1/2 Pathway

BACKGROUND

A number of studies recently revealed a link between periodontal disease and preterm birth (PTB). PTB can be induced by dental infection with Porphyromonas gingivalis (Pg), a periodontopathic bacterium. This study aims to investigate responses of human extravillous trophoblast-derived HTR8/SVneo cells to Pg infection.

METHODS

Cell apoptosis, cell viability, protein expression, and cytokine production in HTR8 cells were measured via: 1) flow cytometry, 2) CCK-8 assay, 3) western blot, and 4) enzyme-linked immunosorbent assay methods, respectively.

RESULTS

Pg decreased cell viability and increased cell apoptosis, active caspase-3 and Fas expression, and interferon-gamma (IFN-γ) secretion in HTR8 cells. Extracellular signal-regulated kinase (ERK) 1/2 inhibitor U0126 and FasL neutralizing antibody NOK1 that blocks FasL/Fas interaction both significantly suppressed Pg-induced apoptosis. U0126 also inhibited IFN-γ secretion and Fas expression close to control levels. Moreover, treatment with recombinant IFN-γ also significantly decreased number of viable HTR8 cells and increased Fas expression, suggesting IFN-γ may play an important role in Pg-induced apoptosis of HTR8 cells, at least partially through regulation of Fas expression.

CONCLUSIONS

To the best of the authors' knowledge, this is the first study to demonstrate Pg induces IFN-γ secretion, Fas expression, and apoptosis in human extravillous trophoblast-derived HTR8/SVneo cells in an ERK1/2-dependent manner, and IFN-γ (explored by recombinant IFN-γ) and Fas are involved in Pg-induced apoptosis. The finding that Pg infection abnormally regulates inflammation and apoptosis of human trophoblasts may give new insights into the possible link of PTB with maternal periodontal disease and periodontal pathogens.

Viral single stranded RNA induces a trophoblast pro-inflammatory and antiviral response in a TLR8-dependent and -independent manner

Interest is growing in the role of viral infections and their association with adverse pregnancy outcomes. The trophoblast is permissive to viruses, but little is known about their impact on the placenta. We previously established that viral single stranded RNA (ssRNA), a Toll-like receptor 8 (TLR8) agonist, induces a restricted trophoblast pro-inflammatory cytokine/chemokine response by upregulating the secretion of interleukin (IL)-6 and IL-8. In parallel, the type I interferon, IFNbeta, is produced and acts back on the cell in an autocrine/paracrine manner to trigger caspase-3-dependent apoptosis. In this study, we sought to extend these findings by determining the mechanisms involved, examining whether viral ssRNA could induce a trophoblast antiviral response, and evaluating the influence of viral ssRNA on pregnancy outcome using a mouse model. Viral ssRNA induced human first-trimester trophoblast inflammation, type I interferon production, an antiviral response, and apoptosis in both a TLR8/MyD88-dependent and -independent manner. Furthermore, administration of viral ssRNA to pregnant mice induced placental caspase-3 activation, a pro-inflammatory cytokine/chemokine, type I interferon, and antiviral response as well as immune cell infiltration. Thus, ssRNA viral infections may compromise pregnancy by altering placental trophoblast survival and function through both TLR8 and non-TLR8 signaling pathways, leading to immune changes at the maternal-fetal interface.

Interferon gamma is involved in apoptosis of trophoblast cells at the maternal-fetal interface following Toxoplasma gondii infection

OBJECTIVE

To assess whether interferon gamma (IFN-γ) secreted by decidual natural killer (dNK) cells at the maternal-fetal interface is involved in the apoptosis of trophoblast cells (trophoblasts) following Toxoplasma gondii infection.

METHODS

Human dNK cells were infected with T. gondii and then co-cultured with trophoblasts. The infected co-cultured cells were treated with or without IFN-γ neutralizing antibodies. Uninfected co-cultured cells were used as controls. The level of IFN-γ in the supernatant of co-culture was measured by ELISA and the apoptosis of trophoblasts was analyzed by flow cytometry. The expression of caspase 3 and caspase 8 of trophoblasts cells was determined by Western blotting and real-time RT-PCR.

RESULTS

The levels of IFN-γ were increased at <24h following T. gondii infection and were maintained thereafter. Caspase 3, caspase 8, and the apoptosis of trophoblasts co-cultured with dNK cells were increased compared with the control. Meanwhile, IFN-γ, caspase 3, caspase 8, and trophoblast apoptosis were up-regulated upon increased ratios of dNK cells to trophoblasts. Compared to the infected group, the levels of IFN-γ, caspase 3, caspase 8, and trophoblast apoptosis were significantly decreased upon treatment with the IFN-γ neutralizing antibody. IFN-γ levels were correlated positively with the apoptosis of trophoblasts (r=0.7163, p < 0.01).

CONCLUSIONS

The levels of IFN-γ secreted by dNK cells at the maternal-fetal interface were closely correlated with the apoptosis of trophoblasts upon T. gondii infection. The apoptosis of trophoblasts induced by the increase in IFN-γ depended on the caspase pathway, which may contribute to the abnormal pregnancy outcomes that occur with T. gondii infection.

Identification of microRNAs that regulate TLR2-mediated trophoblast apoptosis and inhibition of IL-6 mRNA

While infection-induced placental inflammation is a common mechanism of adverse pregnancy outcome, some pathogens can also trigger placental apoptosis, and Toll-like receptors (TLRs) mediate this response. Treatment of human first trimester trophoblast cells with bacterial peptidoglycan (PDG) reduces their constitutive secretion of IL-6 protein and induces apoptosis. This apoptotic response is dependent upon the cell’s expression of TLR1, TLR2 and TLR10, and their lack of TLR6, such that ectopic expression of TLR6 prevents PDG-induced apoptosis and restores IL-6 production. In this current study we have identified three microRNAs (miRs) that regulate TLR2-mediated responses in the human trophoblast. Herein we report that miR-329 plays a pivotal role in mediating PDG-induced trophoblast apoptosis and inhibition of IL-6 mRNA expression by targeting the NF-κB subunit, p65. TLR2 activation by PDG upregulates miR-329 expression and inhibits NF-κB p65 and IL-6 mRNA, and this is reversed by the presence of TLR6. Moreover, inhibition of miR-329 prevents PDG-induced inhibition of NF-κB p65 and IL-6 mRNA expression, and restores cell survival. In addition, we have found miR-23a and let-7c to directly regulate PDG-mediated inhibition of IL-6 mRNA. TLR2 activation by PDG upregulates miR23a and let-7c expression and this is reversed by the presence of TLR6. Furthermore, inhibition of both miR23a and let-7c prevents PDG-inhibition of trophoblast IL-6 mRNA expression. Together, our findings suggest that multiple miRs are involved in the molecular regulation of TLR2-mediated responses in the trophoblast towards gram-positive bacterial components.

HO-1 as modulator of the innate immune response in pregnancy

PROBLEM

The immune modulatory effect of heme oxygenase-1 (HO-1) is well documented in studies about sepsis and transplantation. This work evaluates the influence of HO-1 on the innate immune response during pregnancy.

METHOD OF STUDY

Human first-trimester trophoblasts derived from normal pregnancies or spontaneous abortions were analyzed for their basal HO-1, BCL-associated athanogene-1 (Bag-1), and cytokine production before and after LPS treatment. In vivo, pregnant Hmox1+/+ and Hmox1+/- female mice were treated with LPS, and the production of Bag-1 was evaluated.

RESULTS

Human trophoblasts up-regulated the expression of both HO-1 and pro-inflammatory cytokines after LPS treatment, whereas the basal level of HO-1 was higher in normal pregnancies. In vivo, HO-1 deficiency provoked diminished Bag-1 level upon LPS treatment.

CONCLUSION

HO-1 deficiency causes an inflammatory immune reaction and diminished expression of protective molecules in trophoblasts. Thus, HO-1 emerges as one important modulator of innate immune responses in pregnancy.

Are placental Fas and Fas ligand gene polymorphisms associated with preeclampsia?

OBJECTIVE

Increased placental trophoblastic apoptosis has been reported in pregnancies complicated by preeclampsia. Fas-Fas ligand is one of the major signal transduction pathways of apoptosis. The objective of this study was to determine if placental Fas and Fas ligand gene polymorphisms differ between patients with and without preeclampsia.

STUDY DESIGN

Forty-five singleton placentas were studied. Twenty-three placentas were from preeclamptic pregnancies and 22 were from normotensive controls. Genotyping was performed for Fas-1377, Fas-691, Fas-670, Fas ligand-844, Fas ligand-1174, Fas ligand-2777. Chi-square and Fisher's exact tests were used for statistical analysis.

RESULTS

There were no significant differences in maternal age, parity or race between the two groups. There were no significant differences in genotypes or allele frequencies for the Fas-1377, Fas-691, Fas-670, Fas ligand-844, Fas ligand-1174 and Fas ligand-2777.

CONCLUSION

Immune intolerance of maternal and placental interaction plays an important role in the pathogenesis of preeclampsia. Our findings do not support the role of placental Fas and Fas ligand gene polymorphisms in the pathogenesis of preeclampsia.

Increased resistance to apoptosis during differentiation and syncytialization of BeWo choriocarcinoma cells

Transition from mononuclear villous cytotrophoblast into multinuclear syncytiotrophoblast in the human placenta is accompanied by changes in apoptosis-related proteins and an apparent increased resistance to induced apoptosis. We investigated the specific nature and timing of changes in Bcl-2, Bax, p53, and caspases 3 and 8 in forskolin-treated BeWo choriocarcinoma cells, a model for villous cytotrophoblast differentiation. BeWo cells were treated with forskolin or vehicle alone for up to 72 h and evaluated at 24 h intervals for syncytialization and quantitative expression specific apoptosis-related proteins and mRNAs. Syncytialization was quantified using fluorescent staining of intercellular membranes and enumeration of the percentage of nuclei in multinucleate cells, and differential localization of apoptosis-related proteins to multinuclear or mononuclear cells was determined by quantitative immunofluorescence. Forskolin treatment for up to 72 h resulted in 80% syncytialization, increased expression of Bcl-2 protein (P < 0.01) and mRNA (P < 0.05), and significantly decreased expression of protein and mRNA for Bax, p53, and caspases 3 and 8. Syncytialized cells expressed higher levels of Bcl-2 protein concurrent with increased resistance to cisplatin-induced apoptosis. Thus, syncytialization of BeWo cells was accompanied by altered transcription of apoptotic-related proteins characteristic of increased apoptosis resistance secondary to increased expression of the anti-apoptotic protein Bcl-2 and diminish expression of pro-apoptotic proteins.

Downregulation of ASPP1 in gestational trophoblastic disease: correlation with hypermethylation, apoptotic activity and clinical outcome

Gestational trophoblastic disease encompasses a spectrum of trophoblastic lesions including true neoplasms such as choriocarcinomas and the potentially malignant hydatidiform moles, which may develop persistent disease requiring chemotherapy. ASPP1, a member of apoptosis-stimulating proteins of p53 (ASPPs), is a proapoptotic protein that can stimulate apoptosis through its interaction with p53. We evaluated the promoter methylation and expression profiles of ASPP1 in different trophoblastic tissues and its in vitro functional effect on two choriocarcinoma cell lines, namely JEG-3 and JAR. Significant downregulation of ASPP1 mRNA and protein levels was demonstrated in hydatidiform moles and choriocarcinomas, when compared with normal placentas by quantitative-PCR and immunohistochemistry. The ASPP1 mRNA level was significantly correlated with its hypermethylation status, evaluated with methylation-specific PCR, in placenta and gestational trophoblastic disease samples (P=0.024). Moreover, lower ASPP1 immunoreactivity was shown in hydatidiform moles that progressed to persistent gestational trophoblastic neoplasms than in those that regressed (P=0.045). A significant correlation was also found between expression of ASPP1 and proliferative indices (assessed by Ki67 and MCM7), apoptotic activity (M30 CytoDeath antibody), p53 and caspase-8 immunoreactivities. An in vitro study showed that ectopic expression of ASPP1 could trigger apoptosis through intrinsic and extrinsic pathways as indicated by an increase in cleaved caspase-9 and Fas ligand protein expression. The latter suggests a hitherto unreported novel link between ASPP1 and the extrinsic pathway of apoptosis. Our findings suggest that downregulation of ASPP1 by hypermethylation may be involved in the pathogenesis and progress of gestational trophoblastic disease, probably through its effect on apoptosis.

Toll-like receptors in pregnancy disorders and placental dysfunction

The Toll receptor was originally identified as a regulator of embryogenesis in Drosophila. Toll-like receptors (TLRs) in mammals recognize infectious agents and other danger signals. Activation of TLRs on trophoblast influences immune cell recruitment, cytokine secretion, and decidual responses to invading pathogens during pregnancy. Importantly, biological effects of TLR signal transduction at multiple maternal-fetal interfaces may contribute to several pregnancy pathologies associated with placental dysfunction, including pre-eclampsia, intrauterine growth restriction, and preterm labor. We herein discuss mechanisms by which TLRs regulate the maternal immune response during normal and abnormal gestation, and we highlight recent data that assign a role to TLRs in the pathophysiology of selected pregnancy-associated complications.

Pretreatment with pancaspase inhibitor (Z-VAD-FMK) delays but does not prevent intraperitoneal heat-killed group B Streptococcus-induced preterm delivery in a pregnant mouse model

Caspases and apoptosis are thought to play a role in infection-associated preterm-delivery. We have shown that in vitro treatment with pancaspase inhibitor Z-VAD-FMK protects trophoblasts from microbial antigen-induced apoptosis. Objective. To examine whether in vivo administration of Z-VAD-FMK would prevent infection-induced preterm-delivery. Methods. We injected 14.5 day-pregnant-mice with heat-killed group B streptococcus (HK-GBS). Apoptosis within placentas and membranes was assessed by TUNEL staining. Calpain expression and caspase-3 activation were assessed by immunohistochemistry. Preterm-delivery was defined as expulsion of a fetus within 48 hours after injection. Results. Intrauterine (i.u.) or intraperitoneal (i.p.) HK-GBS injection led to preterm-delivery and induced apoptosis in placentas and membranes at 14 hours. The expression of calpain, a caspase-independent inducer of apoptosis, was increased in placenta. Treatment with the specific caspase inhibitor Z-VAD-FMK (i.p.) prior to HK-GBS (i.p.) delayed but did not prevent preterm-delivery. Conclusion. Caspase-dependent apoptosis appears to play a role in the timing but not the occurrence of GBS-induced preterm delivery in the mouse.

An introduction to Toll-like receptors and their possible role in the initiation of labour

Toll-like receptors (TLR) have emerged as key upstream mediators of inflammation at many tissue sites in humans. Inflammatory processes are involved in the process of parturition suggesting that TLR activity within gestation-associated tissues might have an important role in the initiation and/or maintenance of normal term labour and in various pathological states of pregnancy such as infection-associated preterm labour. Either TLRs or their signalling molecules might be excellent therapeutic targets for prevention of preterm labour.

Toll-like receptor-2 expression in normal and pathologic human placenta

Toll-like receptors (TLRs) are important components of the innate immune system and are expressed by trophoblast in normal full-term placenta. At present, not much is known about the role of TLRs during normal pregnancy and in pregnancy complicated by infection. In this study, we have used immunohistochemistry to investigate the expression of TLR2 in 58 placentas from second and third trimester with chorioamnionitis and 25 full-term placentas from uncomplicated pregnancies without chorioamnionitis. TLR2 was found to be localized to the cyto- and syncytio-trophoblast cell layer and to decidual stromal cells. The expression of TLR2 in placentas with chorioamnionitis was significantly lower than in placentas without chorioamnionitis. Furthermore, there was a significantly higher expression in placentas from liveborn children than in placentas from stillborn/aborted fetuses and also a higher expression in second- than in third-trimester placentas. These data suggest that TLR2 expression in the trophoblast could be involved in the response to infectious pathogens in the placenta.

ChlamydiaHeat Shock Protein 60 Induces Trophoblast Apoptosis through TLR4

Intrauterine infection affects placental development and function, and subsequently may lead to complications such as preterm delivery, intrauterine growth retardation, and preeclampsia; however, the molecular mechanisms are not clearly known. TLRs mediate innate immune responses in placenta, and recently, TLR2-induced trophoblast apoptosis has been suggested to play a role in infection-induced preterm delivery. Chlamydia trachomatis is the etiological agent of the most prevalent sexually transmitted bacterial infection in the United States. In this study, we show that in vitro chlamydial heat shock protein 60 induces apoptosis in primary human trophoblasts, placental fibroblasts, and the JEG3 trophoblast cell line, and that TLR4 mediates this event. We observed a host cell type-dependent apoptotic response. In primary placental fibroblasts, chlamydial heat shock protein 60-induced apoptosis was caspase dependent, whereas in JEG3 trophoblast cell lines it was caspase independent. These data suggest that TLR4 stimulation induces apoptosis in placenta, and this could provide a novel mechanism of pathogenesis for poor fertility and pregnancy outcome in women with persistent chlamydia infection.

FLICE-inhibitory Protein: Expression in Early and Late Gestation Human Placentas

The apoptosis cascade that plays a central role in normal and pathological processes is strictly controlled, in part by FLIP (Fas-associated death domain-like interleukin-1beta-converting enzyme-inhibitory protein), an inhibitor of caspase-8. Here, we report the expression of long and short isoforms of FLIP mRNAs and proteins in early and late gestation human placentas, term cytotrophoblast cells and two choriocarcinoma cell lines, JEG-3 and Jar. Reverse transcriptase polymerase chain reaction identified mRNAs derived from the FLIP gene in all samples. Analysis by immunoblotting revealed that both long and short forms of FLIP proteins are present in early and late gestation human placentas with increasing levels over gestation and that FLIP proteins are present in normal and transformed trophoblast cells. Immunohistochemical experiments performed on paraformaldehyde-fixed tissue sections taken from early and late stages of pregnancy demonstrated that FLIP proteins are present in caspase-8-expressing cells and that expression patterns of FLIP differed according to cell lineage and stage of cell differentiation. The results of this study are consistent with the postulate that FLIP proteins have critical roles in placental cell survival and suggest that FLIP may protect normal and transformed trophoblast cells from cell death.

Trophoblast Cells as Immune Regulators

Medawar, in the early 1950s, recognized for the first time, the unique immunology of the maternal-fetal interface and its potential relevance for transplantation. In his original work, he described the “fetal allograft analogy” whereby the fetus may be viewed as a semi-allogeneic conceptus that has evaded rejection by the maternal immune system. Although numerous hypotheses have been proposed to prove this observation, none have demonstrated that the maternal immune system is antagonist to the invading trophoblast. In the present manuscript we have reviewed recent studies demonstrating the expression and function of TLRs in trophoblast cells and based on this data we propose an alternative view for maternal-fetal immune interactions.

Toll-like receptors and their role in the trophoblast

The aim of this review is to discuss the role of Toll-like receptors at the maternal-fetal interface and the capacity of trophoblast cells to initiate innate immune responses towards infection. The maternal-fetal interface represents an immunologically unique site that must promote tolerance to the allogenic fetus, whilst maintaining host defense against a diverse array of possible pathogens. Clinical studies have shown a strong association between certain complications of pregnancy and intrauterine infections. Therefore, innate immune responses against microorganisms at the maternal-fetal interface may have a significant impact on the success of a pregnancy. There is growing evidence that trophoblast cells are able to recognize and respond to pathogens through the expression of Toll-like receptors, an important part of innate immunity. This review will discuss the role of Toll-like receptors at the maternal-fetal interface, the potential for trophoblast cells to function as components of the innate immune system and the impact TLR-mediated trophoblast responses may have on pregnancy outcome.

Programmed cell death (apoptosis) in placentas from normal pregnancy and pregnancy complicated by term (t) and preterm (p) premature rupture of membranes (PROM)

OBJECTIVE

The aim of this study was to determine the apoptotic index using three different apoptotic markers: terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL); M30 cytoDEATH antibody and fluorescein isothiocyanate (FTIC)-labeled annexin-V in the placenta and membranes from normal pregnancy and pregnancy complicated by premature rupture of membranes (PROM).

STUDY DESIGN

Placentas from 16 pregnancies (22-40 weeks' gestation) and 13 pregnancies complicated by pPROM and tPROM were collected at delivery. Maternal and gestational age, mode of delivery, gravidity and parity, fetal birthweight, Apgar scores, presence of histologic chorioamnionitis, interval between membrane rupture and delivery were recorded among PPROM and tPROM cases.

RESULTS

Only M30 cytoDEATH antibody (P=0.02) and TUNEL test (P=0.04) on fetal membranes gave statistically significantly higher levels in cases with premature rupture of membranes. The presence of histologic chorioamnionitis had no significant impact on apoptotic markers in PROM placentas. Preterm deliveries following the rupture of membranes had higher median AI values detected by M30M antibody, compared to those cases delivered without PROM (P=0.03).

CONCLUSION

High apoptotic nuclei counts were found in fetal membranes of pPROM.

Polymorphisms in immunoregulatory genes and the risk of histologic chorioamnionitis in Caucasoid women: a case control study

Background

Chorioamnionitis is a common underlying cause of preterm birth (PTB). It is hypothesised that polymorphisms in immunoregulatory genes influence the host response to infection and subsequent preterm birth. The relationship between histologic chorioamnionitis and 22 single nucleotide polymorphisms in 11 immunoregulatory genes was examined in a case-control study.

Methods

Placentas of 181 Caucasoid women with spontaneous PTB prior to 35 weeks were examined for histologic chorioamnionitis. Polymorphisms in genes IL1A, IL1B, IL1RN, IL1R1, tumour necrosis factor (TNF), IL4, IL6, IL10, transforming growth factor beta-1 (TGFB1), Fas (TNFRSF6), and mannose-binding lectin (MBL2) were genotyped by polymerase chain reaction and sequence specific primers. Multivariable logistic regression including demographic and genetic variables and Kaplan-Meier survival analyses of genotype frequencies and pregnancy outcome were performed.

Results

Sixty-nine (34%) women had histologic evidence of acute chorioamnionitis. Carriage of the IL10-1082A/-819T/592A (ATA) haplotype [Multivariable Odds ratio (MOR) 1.9, P = 0.05] and MBL2 codon 54Asp allele (MOR 2.0, P = 0.04), were positively associated with chorioamnionitis, while the TNFRSF6-1377A/-670G (AG) haplotype (MOR 0.4, P = 0.03) and homozygosity for TGFB1-800G/509T (GT) haplotype (MOR 0.2, P = 0.04) were negatively associated.

Conclusion

These findings demonstrate that polymorphisms in immunoregulatory genes IL10, MBL2, TNFRSF6 and TGFB1 may influence susceptibility to chorioamnionitis.

Placental Fas and Fas ligand expression in normal early, term and molar pregnancy

To clarify the Fas and Fas-ligand status of normal and molar trophoblast, the expression of Fas and FasL by placental trophoblast populations in partial and complete hydatidiform moles was compared with that in normal first trimester and term pregnancies using an avidin-biotin peroxidase technique on frozen and formalin-fixed paraffin-embedded placental tissues with both monoclonal and polyclonal antibodies. The TUNEL technique was used to detect apoptotic cells in the same tissues. The immunoreactivity for Fas and Fas-ligand was comparable with both monoclonal and polyclonal antibodies on frozen as well as paraffin-embedded sections. In normal early and molar pregnancy there was strong FasL expression by villous cytotrophoblast and syncytiotrophoblast. However, there were significant differences in FasL expression by trophoblast subpopulations in both early and term normal pregnancy and between the same trophoblast subpopulation at different gestations, with FasL staining generally being weaker at term. Strong FasL staining by cytotrophoblast cells in the distal parts of cell columns contrasted with unstained cytotrophoblast in the proximal part of columns. Distinct trophoblast subpopulations in partial hydatidiform mole also differentially expressed FasL with reduced FasL expression in proliferating syncytiotrophoblast. In contrast there was no differential FasL expression in complete hydatidiform mole, all trophoblast subpopulations strongly expressing FasL. Unlike the differential expression of FasL there were no differences in Fas expression by trophoblast populations in normal early or term placental tissues. Fas expression was reduced in villous cytotrophoblast at term. Differential expression of Fas by different trophoblast subpopulations was noted in partial and complete hydatidiform mole. In complete mole villous cytotrophoblast and syncytiotrophoblast stained strongly compared with proliferating trophoblast. Using TUNEL labelling apoptosis was rarely detected in placental trophoblast. Differential Fas and FasL expression by trophoblast subpopulations in normal and pathological pregnancy does not appear to be related to apoptosis of trophoblast.