Chorioamnionitis and increased galectin-1 expression in PPROM --an anti-inflammatory response in the fetal membranes?

Galectin-1 Elicits a Tissue-Specific Anti-Inflammatory and Anti-Degradative Effect Upon LPS-Induced Response in an Ex Vivo Model of Human Fetal Membranes Modeling an Intraamniotic Inflammation

PROBLEM

Intrauterine infection is one of the most jeopardizing conditions associated with adverse outcomes, including preterm birth; however, multiple tolerance mechanisms operate at the maternal-fetal interface to avoid the rejection of the fetus. Among the factors that maintain the uterus as an immunoprivileged site, Galectin-1 (Gal-1), an immunomodulatory glycan-binding protein secreted by the maternal-fetal unit, is pivotal in promoting immune cell homeostasis. This work aimed to evaluate the role of Gal-1 during a lipopolysaccharide (LPS)-induced-inflammatory milieu.

METHOD OF STUDY

Using an ex vivo culture with two independent compartments, human fetal membranes at term were pretreated with 40 and 80 ng/mL of Gal-1, then to reproduce an intraamniotic inflammation, the fetal side of membranes was stimulated with 500 ng/mL of LPS for 24 h. The concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, monocyte chemoattractant protein (MCP1), macrophage inflammatory protein (MIP1) α, regulated upon activation normal T cell expressed and secreted (RANTES), and matrix metalloproteinase (MMP)-9 were measured in both amnion and choriodecidua compartments.

RESULTS

In a tissue-specific fashion profile, pretreatment with the physiologic concentration of Gal-1 significantly diminished the LPS-dependent secretion of TNF-α, IL-1β, Il-6, MCP1, MIP1α, RANTES, and MMP-9.

CONCLUSION

Gal-1 elicits an anti-inflammatory effect on the human fetal membranes stimulated with LPS, which supports the hypothesis that Gal-1 is part of the immunomodulatory mechanisms intended to stop the harmful effect of inflammation of the maternal-fetal interface.

Galectin-7 Expression in the Placentas of Women with Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a common condition during pregnancy. The prevalence of GDM is continuously increasing worldwide. Due to accessible diagnostic methods and a clear understanding of risk factors, GDM can be effectively diagnosed and managed. Galectins may influence immunomodulatory and inflammatory processes. This study examines the expression of galectin-7 in the placentas of women with gestational diabetes (GDM), compares it to its expression in healthy pregnancies, and evaluates the associated clinical outcomes. The placentas of 40 healthy women and 40 GDM placentas were included in the cohort. The expression level of galecin-7 was measured in the syncytiotrophoblast (SCT) and in the decidua of the placenta by immunohistochemistry and double immunofluorescence staining. The evaluation was performed by an immunoreactivity score (IRS). The study results show an increased expression of galectin-7 in the SCT and the decidua of GDM placentas as compared to the placentas of the control group. Elevated levels of galectin-7 were observed in both the nucleus and the cytoplasm. This study investigated the hypothesis that galectins are involved in pathophysiological processes of gestational diabetes. Statistical analysis of gene expression patterns confirmed that galectin-7 is indeed upregulated in GDM placentas. Further studies are needed to show the correlation of galectin-7 and the development and maintenance of gestational diabetes mellitus.

Proteomic profile of extracellular vesicles in maternal plasma of women with fetal death

OBJECTIVES

Fetal death is a complication of pregnancy caused by multiple etiologies rather than being the end-result of a single disease process. Many soluble analytes in the maternal circulation, such as hormones and cytokines, have been implicated in its pathophysiology. However, changes in the protein content of extracellular vesicles (EVs), which could provide additional insight into the disease pathways of this obstetrical syndrome, have not been examined. This study aimed to characterize the proteomic profile of EVs in the plasma of pregnant women who experienced fetal death and to evaluate whether such a profile reflected the pathophysiological mechanisms of this obstetrical complication. Moreover, the proteomic results were compared to and integrated with those obtained from the soluble fraction of maternal plasma.

METHODS

This retrospective case-control study included 47 women who experienced fetal death and 94 matched, healthy, pregnant controls. Proteomic analysis of 82 proteins in the EVs and the soluble fractions of maternal plasma samples was conducted by using a bead-based, multiplexed immunoassay platform. Quantile regression analysis and random forest models were implemented to assess differences in the concentration of proteins in the EV and soluble fractions and to evaluate their combined discriminatory power between clinical groups. Hierarchical cluster analysis was applied to identify subgroups of fetal death cases with similar proteomic profiles. A p-value of <.05 was used to infer significance, unless multiple testing was involved, with the false discovery rate controlled at the 10% level (q < 0.1). All statistical analyses were performed by using the R statistical language and environment-and specialized packages.

RESULTS

Nineteen proteins (placental growth factor, macrophage migration inhibitory factor, endoglin, regulated upon activation normal T cell expressed and presumably secreted (RANTES), interleukin (IL)-6, macrophage inflammatory protein 1-alpha, urokinase plasminogen activator surface receptor, tissue factor pathway inhibitor, IL-8, E-Selectin, vascular endothelial growth factor receptor 2, pentraxin 3, IL-16, galectin-1, monocyte chemotactic protein 1, disintegrin and metalloproteinase domain-containing protein 12, insulin-like growth factor-binding protein 1, matrix metalloproteinase-1(MMP1), and CD163) were found to have different plasma concentrations (of an EV or a soluble fraction) in women with fetal death compared to controls. There was a similar pattern of change for the dysregulated proteins in the EV and soluble fractions and a positive correlation between the log2-fold changes of proteins significant in either the EV or the soluble fraction (ρ = 0.89, p < .001). The combination of EV and soluble fraction proteins resulted in a good discriminatory model (area under the ROC curve, 82%; sensitivity, 57.5% at a 10% false-positive rate). Unsupervised clustering based on the proteins differentially expressed in either the EV or the soluble fraction of patients with fetal death relative to controls revealed three major clusters of patients.

CONCLUSION

Pregnant women with fetal death have different concentrations of 19 proteins in the EV and soluble fractions compared to controls, and the direction of changes in concentration was similar between fractions. The combination of EV and soluble protein concentrations revealed three different clusters of fetal death cases with distinct clinical and placental histopathological characteristics.

Expression and Significance of Galectin-1 and Galectin-3 in the Serum and Placental Tissues of Patients with Intrahepatic Cholestasis of Pregnancy

Background

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease, usually occurring in the third trimester of pregnancy. Its typical clinical manifestations are itching and elevated serum total bile acid levels, which are more harmful to the fetus, and can lead to a variety of adverse pregnancy outcomes. This paper discusses the expressions of galectin -1 and 3 in the serum and placenta of ICP patients and their relationship with the effect of the incidence of ICP.

Methods

Galectin-1 and 3 in serum and placenta were detected in 22 pregnant women with ICP and 20 healthy pregnant women admitted to the obstetrics Department of Northern Jiangsu People's Hospital from May 2021 to February 2022.

Results

Serum levels of galectin-1 and galectin-3 in ICP pregnant women were significantly higher than those in controls, with significant differences (P<0.05). Placental galectin-1 and 3 were higher in normal pregnant women, and there were statistical differences between groups (P<0.05).

Conclusion

In ICP, the maternal serum and placental galectin-1 and 3 levels were significantly increased, both of which may play an important role in the development of ICP, which may be the initiation factor of ICP pathophysiology, a marker of ICP prediction, and a target of ICP prevention strategies.

Galectin-1 and Galectin-9 Concentration in Maternal Serum: Implications in Pregnancies Complicated with Preterm Prelabor Rupture of Membranes

Preterm prelabor rupture of membranes (pPROM) accounts for nearly half of premature births. Although several risk factors have been identified, no markers allowing for effective prevention have been discovered. In this study, we investigated how the maternal serum levels of galectin-1 and galectin-9 change in patients with pPROM in comparison to uncomplicated pregnancies. A total of 75 patients were enrolled to both study and control group (37 vs. 38, respectively). The serum concentration of galectin-1 and galectin-9 were assayed in duplicate using an enzyme-linked immunoassay. All analyses were performed using PQ Stat v. 1.8.4 software. Galectin-1 levels were significantly higher in the controls (13.32 vs. 14.71 ng/mL, p = 0.02). Galectin-9 levels were similar in both groups (13.31 vs. 14.76 ng/mL, p = 0.30). Lower galectin levels were detected for early pPROM (before 32nd GW) in comparison to late pPROM and the controls (8.85 vs. 14.45 vs. 14.71 ng/mL, p = 0.0004). Similar trend was observed in galectin-9 levels, although no statistical significance was found (11.57 vs. 14.25 vs. 14.76 ng/mL, p = 0.26). Low galectin-1 maternal serum level is associated with the incidence of preterm prelabor rupture of membranes. Galectin-9 maternal serum levels were not significantly correlated with pPROM. However, in order to investigate gal-1 and gal-9 levels as potential, promising markers of pPROM, further clinical studies on larger groups are required.

Galectins: Important Regulators in Normal and Pathologic Pregnancies

Galectins (Gal) are characterized by their affinity for galactoside structures on glycoconjugates. This relationship is mediated by carbohydrate recognition domains, which are multifunctional regulators of basic cellular biological processes with high structural similarity among family members. They participate in both innate and adaptive immune responses, as well as in reproductive immunology. Recently, the discovery that galectins are highly expressed at the maternal–fetal interface has garnerd the interest of experts in human reproduction. Galectins are involved in a variety of functions such as maternal–fetal immune tolerance, angiogenesis, trophoblast invasion and placental development and are considered to be important mediators of successful embryo implantation and during pregnancy. Dysregulation of these galectins is associated with abnormal and pathological pregnancies (e.g., preeclampsia, gestational diabetes mellitus, fetal growth restriction, preterm birth). Our work reviews the regulatory mechanisms of galectins in normal and pathological pregnancies and has implications for clinicians in the prevention, diagnosis and treatment of pregnancy-related diseases.

Acute chorioamnionitis and intra-amniotic inflammation are more severe according to outside-in neutrophil migration within the same chorio-decidua

OBJECTIVE

No information exists about whether acute histologic chorioamnionitis (acute-HCA) is more advanced and severe, and intra-amniotic inflammation is more frequent and intense according to outside in neutrophil migration within the same chorio-decidua. The objective of current study is to examine this issue.

MATERIALS AND METHODS

We included 106 singleton preterm-births (gestational age at delivery: 20-34 weeks) due to either preterm-labor or preterm-PROM in the context of acute chorio-deciduitis. Study-population was divided into 3 groups according to outside-in neutrophil migration within chorio-decidua as follows: 1) group-1: 'inflammation restricted to the decidua' (n = 22); 2) group-2: 'inflammation restricted to the MT of chorion and the decidua' (n = 31); 3) group-3: 'inflammation in the CT of chorion' (n = 53). We examined the frequency of inflammation in each placental compartment beyond chorio-decidua (i.e., amnion, umbilical cord, and chorionic-plate), and total grade (1-8) of acute-HCA. Moreover, the frequency of intra-amniotic infection (defined as positive amniotic-fluid culture for aerobic and anaerobic bacteria and genital mycoplasmas) and intra-amniotic inflammation (defined as amniotic fluid WBC ≥ 19 cells/mm³), and an intra-amniotic inflammatory response gauged by amnioticfluid WBC count (cells/mm³) were examined in 50 amniotic fluid samples within 7 days of birth.

RESULTS

Amnionitis, funisitis and chorionic plate inflammation were more frequent (each for P < 0.01) and median total grade of acute-HCA was increased (P < 0.001) according to outside-in neutrophil migration within chorio-decidua (group-1vs.group-2vs.group-3). Moreover, intra-amniotic infection and inflammation were more frequent (each-for P < 0.05) and median amniotic-fluid WBC count was increased (P < 0.01) according-to outside-in neutrophil-migration within chorio-decidua (group-1 vs. group-2 vs. group-3).

CONCLUSION

Acute-HCA is more advanced and severe, and intra-amniotic inflammation is more frequent and intense according to outside in neutrophil migration within the same chorio-decidua. This finding suggests that what is now acute chorio-deciduitis should be subdivided.

Maternal serum galectin-1 and galectin-3 levels in pregnancies complicated with preterm prelabor rupture of membranes

Objective: To investigate maternal serum galectin-1 and galectin-3 levels in pregnancies complicated with preterm prelabor rupture of membranes (PPROM) and to compare with pregnancies delivered at term.Materials and methods: In this cross-sectional study, 40 women with singleton pregnancies complicated with PPROM between 24 and 34 weeks of gestation were compared with gestational age-matched 40 pregnant women with no obstetrics complications, who delivered at term. The maternal serum galectin-1 and galectin-3 levels were measured.Results: Patients complicated with PPROM had significantly higher levels of galectin-1 (p = .001) and galectin-3 (p = .003) than the control group. Maternal serum galectin-3 levels were found significantly negatively correlated with the gestational age at delivery and birth weight.Conclusion: Maternal serum galectin-1 and galectin-3 levels were significantly higher in pregnancies complicated with PPROM. Galectin-1 and galectin-3, with their regulatory effects in key biological processes, may be both an initiating factor in the pathophysiology of PPROM, a marker in the prediction, and a target of preventing strategies of PPROM.

The Role of Extracellular Vesicles and PIBF in Embryo-Maternal Immune-Interactions

Pregnancy represents a unique immunological situation. Though paternal antigens expressed by the conceptus are recognized by the immune system of the mother, the immune response does not harm the fetus. Progesterone and a progesterone induced protein; PIBF are important players in re-adjusting the functioning of the maternal immune system during pregnancy. PIBF expressed by peripheral pregnancy lymphocytes, and other cell types, participates in the feto-maternal communication, partly, by mediating the immunological actions of progesterone. Several splice variants of PIBF were identified with different physiological activity. The full length 90 kD PIBF protein plays a role in cell cycle regulation, while shorter splice variants are secreted and act as cytokines. Aberrant production of PIBF isoforms lead to the loss of immune-regulatory functions, resulting in and pregnancy failure. By up regulating Th2 type cytokine production and by down-regulating NK activity, PIBF contributes to the altered attitude of the maternal immune system. Normal pregnancy is characterized by a Th2-dominant cytokine balance, which is partly due to the action of the smaller PIBF isoforms. These bind to a novel form of the IL-4 receptor, and induce increased production of IL-3, IL-4, and IL-10. The communication between the conceptus and the mother is established via extracellular vesicles (EVs). Pre-implantation embryos produce EVs both in vitro, and in vivo. PIBF transported by the EVs from the embryo to maternal lymphocytes induces increased IL-10 production by the latter, this way contributing to the Th2 dominant immune responses described during pregnancy.

Gene Expression Signatures Point to a Male Sex-Specific Lung Mesenchymal Cell PDGF Receptor Signaling Defect in Infants Developing Bronchopulmonary Dysplasia

Male sex is a risk factor for development of bronchopulmonary dysplasia (BPD), a common chronic lung disease following preterm birth. We previously found that tracheal aspirate mesenchymal stromal cells (MSCs) from premature infants developing BPD show reduced expression of PDGFRα, which is required for normal lung development. We hypothesized that MSCs from male infants developing BPD exhibit a pathologic gene expression profile deficient in PDGFR and its downstream effectors, thereby favoring delayed lung development. In a discovery cohort of 6 male and 7 female premature infants, we analyzed the tracheal aspirate MSCs transcriptome. A unique gene signature distinguished MSCs from male infants developing BPD from all other MSCs. Genes involved in lung development, PDGF signaling and extracellular matrix remodeling were differentially expressed. We sought to confirm these findings in a second cohort of 13 male and 12 female premature infants. mRNA expression of PDGFRA, FGF7, WNT2, SPRY1, MMP3 and FOXF2 were significantly lower in MSCs from male infants developing BPD. In female infants developing BPD, tracheal aspirate levels of proinflammatory CCL2 and profibrotic Galectin-1 were higher compared to male infants developing BPD and female not developing BPD. Our findings support a notion for sex-specific differences in the mechanisms of BPD development.

Integrated Systems Biology Approach Identifies Novel Maternal and Placental Pathways of Preeclampsia

Preeclampsia is a disease of the mother, fetus, and placenta, and the gaps in our understanding of the complex interactions among their respective disease pathways preclude successful treatment and prevention. The placenta has a key role in the pathogenesis of the terminal pathway characterized by exaggerated maternal systemic inflammation, generalized endothelial damage, hypertension, and proteinuria. This sine qua non of preeclampsia may be triggered by distinct underlying mechanisms that occur at early stages of pregnancy and induce different phenotypes. To gain insights into these molecular pathways, we employed a systems biology approach and integrated different "omics," clinical, placental, and functional data from patients with distinct phenotypes of preeclampsia. First trimester maternal blood proteomics uncovered an altered abundance of proteins of the renin-angiotensin and immune systems, complement, and coagulation cascades in patients with term or preterm preeclampsia. Moreover, first trimester maternal blood from preterm preeclamptic patients in vitro dysregulated trophoblastic gene expression. Placental transcriptomics of women with preterm preeclampsia identified distinct gene modules associated with maternal or fetal disease. Placental "virtual" liquid biopsy showed that the dysregulation of these disease gene modules originates during the first trimester. In vitro experiments on hub transcription factors of these gene modules demonstrated that DNA hypermethylation in the regulatory region of ZNF554 leads to gene down-regulation and impaired trophoblast invasion, while BCL6 and ARNT2 up-regulation sensitizes the trophoblast to ischemia, hallmarks of preterm preeclampsia. In summary, our data suggest that there are distinct maternal and placental disease pathways, and their interaction influences the clinical presentation of preeclampsia. The activation of maternal disease pathways can be detected in all phenotypes of preeclampsia earlier and upstream of placental dysfunction, not only downstream as described before, and distinct placental disease pathways are superimposed on these maternal pathways. This is a paradigm shift, which, in agreement with epidemiological studies, warrants for the central pathologic role of preexisting maternal diseases or perturbed maternal-fetal-placental immune interactions in preeclampsia. The description of these novel pathways in the "molecular phase" of preeclampsia and the identification of their hub molecules may enable timely molecular characterization of patients with distinct preeclampsia phenotypes.

Characteristic Changes in Decidual Gene Expression Signature in Spontaneous Term Parturition

Background

The decidua has been implicated in the “terminal pathway” of human term parturition, which is characterized by the activation of pro-inflammatory pathways in gestational tissues. However, the transcriptomic changes in the decidua leading to terminal pathway activation have not been systematically explored. This study aimed to compare the decidual expression of developmental signaling and inflammation-related genes before and after spontaneous term labor in order to reveal their involvement in this process.

Methods

Chorioamniotic membranes were obtained from normal pregnant women who delivered at term with spontaneous labor (TIL, n = 14) or without labor (TNL, n = 15). Decidual cells were isolated from snap-frozen chorioamniotic membranes with laser microdissection. The expression of 46 genes involved in decidual development, sex steroid and prostaglandin signaling, as well as pro- and anti-inflammatory pathways, was analyzed using high-throughput quantitative real-time polymerase chain reaction (qRT-PCR). Chorioamniotic membrane sections were immunostained and then semi-quantified for five proteins, and immunoassays for three chemokines were performed on maternal plasma samples.

Results

The genes with the highest expression in the decidua at term gestation included insulin-like growth factor-binding protein 1 (IGFBP1), galectin-1 (LGALS1), and progestogen-associated endometrial protein (PAEP); the expression of estrogen receptor 1 (ESR1), homeobox A11 (HOXA11), interleukin 1β (IL1B), IL8, progesterone receptor membrane component 2 (PGRMC2), and prostaglandin E synthase (PTGES) was higher in TIL than in TNL cases; the expression of chemokine C-C motif ligand 2 (CCL2), CCL5, LGALS1, LGALS3, and PAEP was lower in TIL than in TNL cases; immunostaining confirmed qRT-PCR data for IL-8, CCL2, galectin-1, galectin-3, and PAEP; and no correlations between the decidual gene expression and the maternal plasma protein concentrations of CCL2, CCL5, and IL-8 were found.

Conclusions

Our data suggests that with the initiation of parturition, the decidual expression of anti-inflammatory mediators decreases, while the expression of pro-inflammatory mediators and steroid receptors increases. This shift may affect downstream signaling pathways that can lead to parturition.

Histological chorioamnionitis in preterm prelabor rupture of the membranes is associated with increased expression of galectin-3 by amniotic epithelium

PURPOSE

Gal-3, which can regulate immune responses upon infection and inflammation, was not studied so far in intrauterine infection leading to preterm prelabor rupture of the membranes (PPROM), although gal-1 was reported to be implicated in the process. Gal-3 mRNA and protein expression in amnion and its changes during histological chorioamnionitis were studied here.

MATERIALS AND METHODS

Fetal membranes were obtained from women with PPROM with (n =15) and without histological chorioamnionitis (n =15) during second and third trimester. Immunohistochemical reactivity was evaluated semiquantitatively and analyzed using t-test. Galectin profile of amniotic epithelia was determined by polymerase chain reaction (PCR) and change assessed in gal-3 in PPROM with (n =5) or without histological chorioamnionitis (n =5) by real-time PCR.

RESULTS

Human amniotic epithelium was found to express gal-1, gal-3, gal-7 and gal-8 mRNA. Gal-3 mRNA and protein is increased in fetal membranes and in the amniotic epithelium in patients with chorionamnionitis.

CONCLUSION

Histological chorioamnionitis is associated with increased gal-3 expression and strong immunoreactivity of the amnion. Gal-3 may participate in the regulation of the inflammatory responses to chorioamniotic infection and/or direct interaction with pathogens.

Neutrophil migration into the placenta: Good, bad or deadly?

Almost 2 decades have passed since the discovery that pregnancy is associated with a basal inflammatory state involving neutrophil activation, and that this is more overt in cases with preeclampsia, than in instances with sepsis. This pivotal observation paved the way for our report, made almost a decade ago, describing the first involvement of neutrophil extracellular traps (NETs) in a non-infectious human pathology, namely preeclampsia, where an abundance of these structures were detected directly in the placental intervillous space.

Despite these remarkable findings, there remains a paucity of interest among reproductive biologists in further exploring the role or involvement of neutrophils in pregnancy and related pathologies. In this review we attempt to redress this deficit by highlighting novel recent findings including the discovery of a novel neutrophil subset in the decidua, the interaction of placental protein 13 (PP13) and neutrophils in modulating spiral artery modification, as well as the use of animal model systems to elucidate neutrophil function in implantation, gestation and parturition. These model systems have been particularly useful in identifying key components implicated in recurrent fetal loss, preeclampsia or new signaling molecules such as sphingolipids. Finally, the recent discovery that anti-phospolipid antibodies can trigger NETosis, supports our hypothesis that these structures may contribute to placental dysfunction in pertinent cases with recurrent fetal loss.

The inflammatory milieu of amniotic fluid in acute-chorioamnionitis decreases with increasing gestational age

INTRODUCTION

The inflammatory milieu decreases in the placenta and amniotic fluid (AF) with gestational age (GA). However, there is no information about whether the inflammatory milieu of AF in the setting of the same placental inflammatory condition decreases with GA. We hypothesized that the inflammatory milieu of AF in acute chorioamnionitis would decrease with increasing GA.

METHODS

The inflammatory milieu of AF was examined in 617 singleton preterm pregnancies (<36 weeks) delivered within 5 days of amniocentesis. Study population was divided into GA at delivery ≤30 weeks (n = 148), 30-34 weeks (n = 226), and 34-36 weeks (n = 226). Acute-chorioamnionitis was classified according to the severity (i.e., mild, total grade 1; moderate, total grade 2; and severe, total grade 3-6) or involved compartment (i.e., chorionic plate, amnion and chorio-decidua). The inflammatory milieu of AF was determined by matrix metalloproteinase-8 (MMP-8) concentration.

RESULTS

1) AF MMP-8 concentrations decreased in patients with acute-chorioamnionitis (P < 0.001), but not inflammation-free placenta, with increasing GA; 2) AF MMP-8 concentrations were less intense at higher GA in patients with moderate and severe (each-for P < 0.005), but not mild, acute-chorioamnionitis; 3) AF MMP-8 concentrations decreased in the context of the same involved compartment (i.e., chorionic plate inflammation, amnionitis, or chorio-deciduitis) of acute-chorioamnionitis (each-for P < 0.001) with increasing GA; 4) Moreover, there was a significant inverse relationship between GA and AF MMP-8 concentrations in patients with acute-chorioamnionitis (r = -0.453, P < 0.0000001), but not inflammation-free placenta (r = -0.071, P = 0.170).

DISCUSSION

AF MMP-8 concentrations in acute-chorioamnionitis distinctly decrease throughout preterm-gestation. This finding suggests that the inflammatory milieu of AF decrease in acute-chorioamnionitis with GA.

Galectins: Double-edged Swords in the Cross-roads of Pregnancy Complications and Female Reproductive Tract Inflammation and Neoplasia

Galectins are an evolutionarily ancient and widely expressed family of lectins that have unique glycan-binding characteristics. They are pleiotropic regulators of key biological processes, such as cell growth, proliferation, differentiation, apoptosis, signal transduction, and pre-mRNA splicing, as well as homo- and heterotypic cell-cell and cell-extracellular matrix interactions. Galectins are also pivotal in immune responses since they regulate host-pathogen interactions, innate and adaptive immune responses, acute and chronic inflammation, and immune tolerance. Some galectins are also central to the regulation of angiogenesis, cell migration and invasion. Expression and functional data provide convincing evidence that, due to these functions, galectins play key roles in shared and unique pathways of normal embryonic and placental development as well as oncodevelopmental processes in tumorigenesis. Therefore, galectins may sometimes act as double-edged swords since they have beneficial but also harmful effects for the organism. Recent advances facilitate the use of galectins as biomarkers in obstetrical syndromes and in various malignancies, and their therapeutic applications are also under investigation. This review provides a general overview of galectins and a focused review of this lectin subfamily in the context of inflammation, infection and tumors of the female reproductive tract as well as in normal pregnancies and those complicated by the great obstetrical syndromes.

Expression and function of galectins in the endometrium and at the human feto-maternal interface

Galectins are classified as lectins that share structural similarities and bind β-galactosides via a conserved carbohydrate recognition domain. So far 16 out of 19 identified galectins were shown to be present in humans and numerous studies revealed galectins as pivotal modulators of cell death, differentiation and growth. Galectins were highlighted to interact with both the adaptive and innate immune response. In the field of reproductive medicine and placenta research different roles for galectins have been proposed. Several galectins, being abundantly present at the human feto-maternal interphase and endometrium, were hypothesized to significantly contribute to endometrial receptivity and pregnancy physiology. Hence, this review outlines selected aspects of galectin action within endometrial function and at the feto-maternal interphase. Further current knowledge on galectins in reproductive and pregnancy disorders like endometriosis, abortion or preeclampsia is summarized.

Interleukin-33 in the human placenta

OBJECTIVE

Interleukin-33 (IL-33) is the newest member of the IL-1 cytokine family, a group of key regulators of inflammation. The purpose of this study was to determine whether IL-33 is expressed in the human placenta and to investigate its expression in the context of acute and chronic chorioamnionitis.

METHODS

Placental tissues were obtained from five groups of patients: 1) normal pregnancy at term without labor (n = 10); 2) normal pregnancy at term in labor (n = 10); 3) preterm labor without inflammation (n = 10); 4) preterm labor with acute chorioamnionitis and funisitis (n = 10); and 5) preterm labor with chronic chorioamnionitis (n = 10). Immunostaining was performed to determine IL-33 protein expression patterns in the placental disk, chorioamniotic membranes, and umbilical cord. mRNA expression of IL-33 and its receptor IL1RL1 (ST2) was measured in primary amnion epithelial and mesenchymal cells (AECs and AMCs, n = 4) and human umbilical vein endothelial cells (HUVECs, n = 4) treated with IL-1β (1 and 10 ng/ml) and CXCL10 (0.5 and 1 or 5 ng/ml).

RESULTS

1) Nuclear IL-33 expression was found in endothelial and smooth muscle cells in the placenta, chorioamniotic membranes, and umbilical cord; 2) IL-33 was detected in the nucleus of CD14+ macrophages in the chorioamniotic membranes, chorionic plate, and umbilical cord, and in the cytoplasm of myofibroblasts in the Wharton's jelly; 3) acute (but not chronic) chorioamnionitis was associated with the presence of IL-33+ macrophages in the chorioamniotic membranes and umbilical cord; 4) expression of IL-33 or IL1RL1 (ST2) mRNA in AECs was undetectable; 5) IL-33 mRNA expression increased in AMCs and HUVECs after IL-1β treatment but did not change with CXCL10 treatment; and 6) IL1RL1 (ST2) expression decreased in AMCs and increased in HUVECs after IL-1β but not CXCL10 treatment.

CONCLUSIONS

IL-33 is expressed in the nucleus of placental endothelial cells, CD14+ macrophages, and myofibroblasts in the Wharton's jelly. IL-1β can induce the expression of IL-33 and its receptor. Protein expression of IL-33 is detectable in macrophages of the chorioamniotic membranes in acute (but not chronic) chorioamnionitis.

Galectins: guardians of eutherian pregnancy at the maternal-fetal interface

Galectins are multifunctional regulators of fundamental cellular processes. They are also involved in innate and adaptive immune responses, and play a functional role in immune-endocrine crosstalk. Some galectins have attracted attention in the reproductive sciences because they are highly expressed at the maternal-fetal interface, their functional significance in eutherian pregnancies has been documented, and their dysregulated expression is observed in the 'great obstetrical syndromes'. The evolution of these galectins has been linked to the emergence of eutherian mammals. Based on published evidence, galectins expressed at the maternal-fetal interface may serve as important proteins involved in maternal-fetal interactions, and the study of these galectins may facilitate the prediction, prevention, diagnosis, and treatment of pregnancy complications.

Placental protein 13 and decidual zones of necrosis: an immunologic diversion that may be linked to preeclampsia

We evaluated the role of placental protein 13 (PP13; galectin 13) in the process of trophoblast invasion and decidual necrosis. Immunohistochemical analysis for PP13, immune cells, human placental lactogen, cytokeratin, and apoptosis markers was performed on 20 elective pregnancy termination specimens between 6 and 15 weeks of gestation. Placental protein 13 was localized to syncytiotrophoblasts in the chorionic villi and to occasional multinucleated luminal trophoblasts within converted decidual spiral arterioles. Cytotrophoblasts, anchoring trophoblasts, and invasive trophoblasts did not stain for PP13. Extracellular PP13 aggregates were found around decidual veins associated with T-cell-, neutrophil- and macrophage-containing decidual zones of necrosis (ZONEs). We hypothesize that PP13 is secreted into the intervillus space, drains through the decidua basalis veins, and forms perivenous PP13 aggregates which attract and activate maternal immune cells. Thus, syncytiotrophoblast-derived PP13 may create a ZONE that facilitates trophoblast invasion and conversion of the maternal spiral arterioles.

Trichomoniasis: evaluation to execution

Trichomoniasis is the most common sexually transmitted disease, caused by a motile flagellate non-invasive parasitic protozoan, Trichomonas vaginalis (T. vaginalis). More than 160 million people worldwide are annually infected by this protozoan. T. vaginalis occupies an extracellular niche in the complex human genito-urinary environment (vagina, cervix, penis, prostate gland, and urethra) to survive, multiply and evade host defenses. T. vaginalis (strain G3) has a ∼160 megabase genome with 60,000 genes, the largest number of genes ever identified in protozoans. The T. vaginalis genome is a highly conserved gene family that encodes a massive proteome with one of the largest coding (expressing ∼4000 genes) capacities in the trophozoite stage, and helps T. vaginalis to adapt and survive in diverse environment. Based on recent developments in the field, we review T. vaginalis structure, patho-mechanisms, parasitic virulence, and advances in diagnosis and therapeutics.

Resistin levels in preterms: are they influenced by fetal inflammatory course?

OBJECTIVE

Many different factors are involved in the pathogenesis of preterm deliveries and among them maternal or perinatal infections and inflammatory response have the major role. Researches were carried out about resistin, which is thought to have a role in inflammatory cytokine cycle and it was shown to be associated with growth in neonates. However, no research has been carried out showing its relationship with inflammation in neonates. In this study, we aimed to evaluate the resistin levels in premature neonates and the effect of events such as preterm prelabour rupture of the membranes (PPROMs) and the use of antenatal steroids on these levels.

STUDY DESIGN

The study included 118 preterm neonates. Their medical data together with their mothers' were recorded. Serum resistin levels together with interleukin (IL)-6, C-reactive protein (CRP) and procalcitonin were evaluated in the first 2 h of life.

RESULT

Mean gestational age and birth weight of babies included in the study were 29.6 ± 2.7 weeks and 1306.4 ± 393.4 g, respectively. Babies with PPROMs had significantly higher levels of resistin ((n=30); 70.7 (7.8 to 568.4) ng ml(-1)) than babies without PPROM ((n=88); 25.9 (5.5 to 528.9) ng ml(-1)) (P=0.005), and the babies of mothers who received antenatal steroids had significantly lower resistin levels ((n=44); 20.8 (5.5 to 159.9) ng ml(-1)) than the babies of mothers who did not ((n=66); 34.6 (7.2 to 568.4) ng ml(-1)) (P=0.015). There were significant correlations between resistin and IL-6 levels and between IL-6 and procalcitonin and CRP levels in babies whose mothers did not receive antenatal steroids. However, no correlation was found between these parameters in babies whose mothers received antenatal steroids.

CONCLUSION

Preterm delivery and PPROM involve complex cascade of events including inflammation, and steroids are potent anti-inflammatory agents. Elevated resistin levels in babies with PPROM and suppressed levels in babies whose mothers received antenatal steroids reported in this study might have been observed as a result of the effects of fetal inflammation on resistin levels.

Hyperresistinemia - a novel feature in systemic infection during human pregnancy

PROBLEM

Resistin, originally described as an adipokine, has emerged as a potent pro-inflammatory protein associated with both acute and chronic inflammation. Moreover, resistin has been proposed as a powerful marker of sepsis severity, as well as a predictor of survival of critically ill non-pregnant patients. The aim of this study was to determine whether pyelonephritis during pregnancy is associated with changes in maternal plasma resistin concentrations.

METHODS OF STUDY

This cross-sectional study included the following groups: (i) normal pregnant women (n = 85) and (ii) pregnant women with pyelonephritis (n = 40). Maternal plasma resistin concentrations were determined by ELISA. Non-parametric statistics was used for analyses.

RESULTS

(i) The median maternal plasma resistin concentration was higher in patients with pyelonephritis than in those with a normal pregnancy (P < 0.001); (ii) among patients with pyelonephritis, the median maternal resistin concentration did not differ significantly between those with and without a positive blood culture (P = 0.3); (iii) among patients with pyelonephritis who were diagnosed with systemic inflammatory response syndrome (SIRS), those who fulfilled > or =3 criteria for SIRS had a significantly higher median maternal plasma resistin concentration than those who met only two criteria; and (iv) maternal WBC count positively correlated with circulating resistin concentration (r = 0.47, P = 0.02).

CONCLUSION

Hyperresistinemia is a feature of acute pyelonephritis during pregnancy. The results of this study support the role of resistin as an acute-phase protein in the presence of bacterial infection during pregnancy.

Maternal plasma concentration of the pro-inflammatory adipokine pre-B-cell-enhancing factor (PBEF)/visfatin is elevated in pregnant patients with acute pyelonephritis

PROBLEM

Visfatin/pre-B-cell-enhancing factor (PBEF) has been implicated in the regulation of the innate immune system, as well as in glucose metabolism. Specifically, visfatin plays a requisite role in delayed neutrophil apoptosis in patients with sepsis. The aim of this study was to determine whether pyelonephritis during pregnancy is associated with changes in maternal plasma visfatin concentration in normal weight and overweight/obese patients.

METHOD OF STUDY

This cross-sectional study included the following groups: (1) normal pregnant women (n = 200) and (2) pregnant women with pyelonephritis (n = 40). Maternal plasma visfatin concentrations were determined by ELISA. Non-parametric statistics was used for analyses.

RESULTS

(1) The median maternal plasma visfatin concentration was significantly higher in patients with pyelonephritis than in those with a normal pregnancy; (2) among overweight/obese pregnant women, those with pyelonephritis had a significantly higher median plasma visfatin concentration than women with a normal pregnancy; and (3) pyelonephritis was independently associated with higher maternal plasma visfatin concentrations after adjustment for maternal age, pre-gestational body mass index, smoking status, gestational age at sampling, and birthweight.

CONCLUSION

Acute pyelonephritis during pregnancy is associated with a high circulating maternal visfatin concentration. These findings suggest that visfatin/PBEF may play a role in the regulation of the complex and dynamic crosstalk between inflammation and metabolism during pregnancy.

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.

Impact of T. vaginalis infection on innate immune responses and reproductive outcome

Trichomonas vaginalis is the most common non-viral sexually transmitted pathogen. The infection is prevalent in reproductive age women and is associated with vaginitis, endometritis, adnexitis, pyosalpinx, infertility, preterm birth, low birth weight, bacterial vaginosis, and increased risk of cervical cancer, HPV, and HIV infection. In men, its complications include urethritis, prostatitis, epididymitis, and infertility through inflammatory damage or interference with the sperm function. The infection is often asymptomatic and recurrent despite the presence of specific antibodies, suggesting the importance of the innate immune defense. T. vaginalis adhesion proteins, cysteine proteases, and the major parasite lipophosphoglycan (LPG) play distinct roles in the pathogenesis and evasion of host immunity. LPG plays a key role in the parasite adherence and signaling to human vaginal and cervical epithelial cells, which is at least in part mediated by galectins. The epithelial cells respond to T. vaginalis infection and purified LPG by selective upregulation of proinflammatory mediators. At the same time, T. vaginalis triggers an immunosuppressive response in monocytes, macrophages, and dendritic cells. The molecular mechanisms underlying reproductive complications and epidemiologic risks associated with T. vaginalis infection remain to be elucidated.

Emergence of hormonal and redox regulation of galectin-1 in placental mammals: implication in maternal-fetal immune tolerance

Galectin-1 is an anti-inflammatory lectin with pleiotropic regulatory functions at the crossroads of innate and adaptive immunity. It is expressed in immune privileged sites and is implicated in establishing maternal-fetal immune tolerance, which is essential for successful pregnancy in eutherian mammals. Here, we show conserved placental localization of galectin-1 in primates and its predominant expression in maternal decidua. Phylogenetic footprinting and shadowing unveil conserved cis motifs, including an estrogen responsive element in the 5' promoter of LGALS1, that were gained during the emergence of placental mammals and could account for sex steroid regulation of LGALS1 expression, thus providing additional evidence for the role of galectin-1 in immune-endocrine cross-talk. Maximum parsimony and maximum likelihood analyses of 27 publicly available vertebrate and seven newly sequenced primate LGALS1 coding sequences reveal that intense purifying selection has been acting on residues in the carbohydrate recognition domain and dimerization interface that are involved in immune functions. Parsimony- and codon model-based phylogenetic analysis of coding sequences show that amino acid replacements occurred in early mammalian evolution on key residues, including gain of cysteines, which regulate immune functions by redox status-mediated conformational changes that disable sugar binding and dimerization, and that the acquired immunoregulatory functions of galectin-1 then became highly conserved in eutherian lineages, suggesting the emergence of hormonal and redox regulation of galectin-1 in placental mammals may be implicated in maternal-fetal immune tolerance.