Isolation and Immunophenotyping of Leukocytes from the Human Maternal-Fetal Interface.

During human pregnancy, leukocytes that infiltrate the maternal-fetal interface play a major role in establishing a delicate balance between immune tolerance and functional response and setting the inflammatory process that leads to labor. Here we describe two methods for isolating immune cells from the chorioamniotic membranes (decidua parietalis) and placental blood (decidua basalis) that combine gentle enzymatic digestion, magnetic cell sorting, and density gradient. Isolated leukocytes can be immunophenotypified by flow cytometry, and both isolation methods are compatible with downstream cellular and molecular applications, such as cell culture, transcriptome, and proteome analyses.

The Intuitive Eating Scale-2 Adapted for Mexican Pregnant Women: Psychometric Properties and Influence of Sociodemographic Variables.

A weight-inclusive approach to health involves the promotion of intuitive eating, i.e., the individual's ability to be aware of their physiological hunger and satiety cues to determine when and how much to eat, while paying attention to how certain foods affect their body. The second version of the Intuitive Eating Scale (IES-2) evaluates four interrelated traits of intuitive eating: Unconditional Permission to Eat (UPE), Eating for Physical rather than emotional Reasons (EPR), Reliance on internal Hunger/Satiety Cues (RHSC), and Body-Food Choice Congruence (BFCC). In this study, our aim was to evaluate the psychometric properties of a Mexican Spanish adaptation of the IES-2 for pregnant women and examine the relationship between intuitive eating traits and maternal sociodemographic characteristics. A sample of 514 pregnant women answered our IES-2 adaptation and a sociodemographic questionnaire. We determined the quality, validity, and reliability of our adaptation through descriptive measures, frequency distributions, intra-class correlations, and extreme answer group comparison for each item, eliminating those with weak technical properties. We then performed an exploratory principal component analysis and a confirmatory factor analysis. Last, we analyzed the association between intuitive eating and maternal sociodemographic and reproductive variables through correlation tests and multivariable linear regressions. Psychometric tests confirmed the validity and reliability of our IES-2 adaptation, which comprised 18 out of the 23 original items. Notably, both the exploratory and confirmatory factor analyses yielded not four but five factors, due to the EPR subscale splitting in two (the "emotional" and "physical" components of EPR). We attribute this novel finding to the emotional manifestations that naturally accompany pregnancy, which may incline pregnant women to base their eating behaviors more on the emotional than the physical component that would otherwise dominate their EPR trait. Further research is also needed about the UPE subscale during pregnancy, due to item removal and subtle changes in meaning. Finally, the influence of sociodemographic variables on the IES-2 score was extremely low, suggesting that other variables, possibly of a psychological nature, may have greater influence on a pregnant woman's intuitive eating.

A Mexican Spanish Adaptation of the Dutch Eating Behavior Questionnaire: Psychometric Properties and Influence of Sociodemographic Variables in Pregnant Women.

Eating behaviors are complex phenomena, entangling physiological signals of hunger and satiety, food choices, emotional states, and social factors and expectations, as well as food availability and sensory appearance. Evaluating eating behaviors is challenging and must cover different motives. One instrument for such evaluation is the Dutch Eating Behavior Questionnaire (DEBQ), composed of three subscales for exploring emotional eating, external eating, and restrained eating. In this article, we aimed to (1) evaluate the psychometric properties of a Mexican Spanish adaptation of the DEBQ; and (2) explore the associations between the three adapted DEBQ scales and the influence of sociodemographic factors on each of the three eating behaviors in Mexican pregnant women. A sample of 514 pregnant women responded to our adapted version of the DEBQ and a questionnaire about sociodemographic information. We performed an exploratory factor analysis using a principal component analysis with varimax rotation; based on this analysis, we removed items that loaded on two factors and then performed a confirmatory factor analysis. The final version of the adapted DEBQ has 26 items, clearly divided into a three-factor structure and satisfactorily reliable (Cronbach's ⍺ = 0.903). We then performed Spearman bivariate correlations and multivariate linear regression with backward variable selection to test the associations and influence of sociodemographic factors on each of the three eating behaviors evaluated with the DEBQ. In pregnant women, emotional eating (EmoE) had a medium-high correlation with external eating (ExtE) and a low correlation with restrained eating (RestE), while ExtE and RestE showed no association. The three eating behaviors are associated with maternal sociodemographic and reproductive variables, which partly explain their variation, most notably maternal schooling. Our adapted version of the DEBQ is suitable for use with Mexican Spanish-speaking pregnant women. Maternal sociodemographic and reproductive factors have an influence on the variance of eating behaviors during pregnancy.

Infant Feeding Practices That Substitute Exclusive Breastfeeding in a Semi-Rural Mexican Community: Types, Moments, and Associated Factors.

International organizations recommend mothers practice exclusive breastfeeding (EBF) during the first six months of their infant's life and introduce complementary feeding (CF) thereafter while continuing breastfeeding. However, the earlier introduction of liquids and foods is common worldwide and may have negative effects on breastfeeding practice, nutrition, and health. In this formative cross-sectional study, we interviewed 143 mothers from semi-rural communities in Tabasco, Mexico, whose infants were 4-6 months old. We explored (1) which feeding practices substituted EBF and (2) which factors were associated with each practice. During the first month of life, 42.7% of infants received formula milk (FM); this proportion increased to 74.5% by the sixth month. Adjusted Poisson regression analyses showed that giving FM was positively related to working away from home (PR 1.27; 95% CI 1.06, 1.54) and the perception that FM is an important food to accompany breast milk (PR 1.38; 95% CI 1.19, 1.70). Giving FM was negatively associated with not being sure the infant is full after breastfeeding (PR 0.75; 95% CI 0.61, 0.92). Regarding CF, less than half (47.5%) of infants had not received it by the fifth month. Factors positively associated with timely CF introduction were: the mother was told during prenatal care visits the optimal age to start CF is 6 months (PR 1.17, 95% CI 1.06, 1.29); she is convinced that giving only breast milk is best for her baby (PR 1.15, 95% CI 1.03, 1.29), and a higher infant weight-for-length (PR 1.04, 95% CI 1.00, 1.08) and length for age (PR 1.04, 95% CI 1.00, 1.09) z-scores at the study visit; conversely, it was negatively associated to the idea that if the infant is not full, she/he should receive formula milk or some other food (PR 0.87, 95% CI 0.78, 0.96). In these communities, EBF is lost to the use of FM and early CF. The factors associated with these inadequate feeding practices are related to returning to work, information received during prenatal visits, and the mother's beliefs and thoughts. This work will guide the design of an intervention on infant feeding practices for these communities and other similar ones.

Exclusive Breastfeeding and Factors Influencing Its Abandonment During the 1st Month Postpartum Among Women From Semi-rural Communities in Southeast Mexico.

INTRODUCTION: In this study we describe breastfeeding practices among women from semi-rural communities in southeast Mexico, and explore which factors, modifiable or not, are associated with such practices. MATERIALS AND METHODS: This was a formative cross-sectional study that included 143 mothers with infants 4-6 months old, from semi-rural communities in Tabasco, Mexico. We collected data on two categories of factors: (1) women's sociodemographic characteristics, and (2) maternal / infant factors. We first analyzed the frequency of various breastfeeding practices. Then, we classified participants into the up to 1 month of exclusive breastfeeding group ( ≤ 1 m-EBF) and the beyond 1 month EBF group (>1 m-EBF), if they practiced EBF for less or more than 1 month, respectively. We compared the two categories of factors between groups and then, using logistic regression models, explored which factors were associated with practicing >1 m-EBF. RESULTS: By the end of the 1st month postpartum, 51.7% of participants had abandoned EBF, introduced milk formula (35%), other food (9.1%), non-nutritive liquids (7.7%), or had stopped breastfeeding completely. In the next months, EBF practice fell sharply and mixed feeding grew importantly.Logistic regression models showed that women were more likely to be in the >1 m-EBF group if they lived with the baby's father, had complications during pregnancy, delivered vaginally and attended a health center at least three times postpartum. To the contrary, women were less likely to be practice >1 m-EBF if they gave infants other liquids during their hospital stay; experienced pain or discomfort in breasts/nipples, or used a pacifier after hospitalization; had larger bodies (i.e., higher BMI); and believed that you should give the infant powdered milk or some other food when the baby is not full. CONCLUSION: Many factors associated with abandoning EBF, particularly in the early postpartum period, are modifiable and can be altered through timely interventions that include giving correct information and ensuring its comprehension; assertive personal counseling and accompaniment must be provided to mothers; and reinforcement during the early postpartum at health facilities and other settings.

Prolactin Protects the Structural Integrity of Human Fetal Membranes by Downregulating Inflammation-induced Secretion of Matrix Metalloproteinases.

Prolactin (PRL) is a pleiotropic hormone with a key role in pregnancy. In fetal membranes, PRL can regulate the secretion of pro-inflammatory factors, which induces the activation of matrix metalloproteinases (MMPs). The increase and activation of MMPs deregulate the turnover of the extracellular matrix in the fetal membranes, altering its structure and function, causing premature rupture of the membranes and preterm labor. In this work, we evaluate the effect of PRL upon the secretion of MMP-1, MMP-2, MMP-9, MMP-13, and the tissue inhibitors of metalloproteinases (TIMPs) in human fetal membranes after lipopolysaccharide (LPS) challenge. Nine fetal membranes from healthy non-laboring cesarean deliveries at term were cultured in a 2-independent chamber system and pre-treated with 250, 500, 1000 or 4000 ng/ml of PRL for 24 h, then choriodecidual region was stimulated with 500 ng/ml of LPS plus fresh PRL for 24 h. The MMPs and TIMPs secretion were quantified by ELISA, additionally MMP-2 and MMP-9 gelatinolytic activity was measured by zymography. LPS induced the MMP-9 and MMP-1 secretion, but no MMP-2 or MMP-13 in comparison with basal levels. PRL co-treatment decreased the MMP-2, MMP-9 and MMP-1 secretion induced by LPS. The active forms were present in the tissue extract, showing a response consistent with the secretion profile. TIMP-1 and TIMP-2 secretion was decreased after LPS treatment and the PRL co-treatment reverts this effect. The present results support that PRL may favor the balance between these factors involved in the structural maintenance of fetal membranes in an inflammatory event.

Maternal adiposity is associated with inflammatory gene expression in leukocytes at term human pregnancy: A pilot study.

BACKGROUND: Human labor is associated with an inflammatory process that takes place at the maternal-fetal interface, where leukocytes infiltrate and contribute to the local production of effector molecules such as cytokines, chemokines, MMPs, etc. This process may be altered by a low-grade chronic inflammation, characteristic of obesity, resulting in adverse pregnancy outcomes. In this cross-sectional pilot study, we analyzed the relationship between maternal adiposity and inflammation-related gene expression in leukocytes from six healthy women with term pregnancies without labor. METHODS: We estimated maternal adiposity and examined the relative expression of 211 inflammation-related genes in maternal peripheral blood leukocytes (MAT), placental intervillous blood leukocytes (PLA), and choriodecidual leukocytes (CHD) by real-time qPCR. Finally, we analyzed the correlation between maternal adiposity and gene expression. RESULTS: Participants' adiposity ranged from 27.6% to 61.1% (n = 6). The expression of 23 genes significantly differed (p < 0.05) in MAT, PLA, and CHD leukocytes, most of which code for chemokines and proinflammatory cytokines. Importantly, increasing maternal adiposity correlated (r > 0.7) mostly positively with the expression of genes related to activation, migration, infiltration, and proinflammation in MAT (36 genes) and PLA (31 genes). In contrast, in CHD leukocytes maternal adiposity correlated only negatively with seven genes, involved in migration and infiltration. CONCLUSION: Our findings suggest that during term pregnancy, increased maternal adiposity may enhance the priming of peripheral leukocytes, while in choriodecidua it may alter leukocyte recruitment and proinflammatory activity. Maternal adiposity must be considered an important variable in further studies that analyze inflammation-related gene expression in pregnant women.

Erythropoiesis and Red Cell Indices Undergo Adjustments during Pregnancy in Response to Maternal Body Size but not Inflammation.

During human pregnancy, iron requirements gradually increase, leading to higher amounts of erythropoietin (EPO) and reticulocytes, and changes in erythrocyte size and density. Women with pregestational obesity experience "obesity hypoferremia" during pregnancy, which alters iron homeostasis. In this study we aimed to describe the relationship between EPO and iron nutrition status during nonanemic pregnancy, and to explore whether obesity and inflammation influence erythropoiesis and red cell indices. We conducted a secondary analysis of a cohort followed throughout pregnancy. Participants were nonanemic women assigned to two study groups based on pregestational body mass index (pgBMI): adequate weight (AW, n = 53) or obesity (Ob, n = 40). All received a multivitamin supplement. At gestational ages (GA) 13, 21, 28 and 34, we measured hemoglobin and red cell indices with an ACT-5DIFF hematology counter, and reticulocyte percentage by manual cell counting. EPO, interleukin (IL-6) and markers of iron status, i.e., hepcidin, serum transferrin receptor (sTfr) and ferritin, were measured by ELISA. Bivariate correlations showed that EPO was positively associated with pgBMI, GA, sTfr and IL-6, but negatively associated with hepcidin, ferritin and hemoglobin, and unrelated to iron intake. Generalized linear models adjusted for confounding factors showed that EPO and erythrocyte concentrations were significantly higher in women in the Ob group, while mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and red cell distribution width (RDW) were lower; reticulocytes and mean corpuscular hemoglobin concentration (MCHC) were not different. Differences were not altered when controlling for inflammation (IL-6). These changes suggest that, in addition to altering iron metabolism, a larger maternal body size during pregnancy results in higher erythropoiesis without increasing hemoglobin, which is exhibited in the latter being distributed among more and smaller erythrocytes.

Innate Immune Cells and Toll-like Receptor-Dependent Responses at the Maternal-Fetal Interface.

During pregnancy, the placenta, the mother and the fetus exploit several mechanisms in order to avoid fetal rejection and to maintain an immunotolerant environment throughout nine months. During this time, immune cells from the fetal and maternal compartments interact to provide an adequate defense in case of an infection and to promote a tolerogenic milieu for the fetus to develop peacefully. Trophoblasts and decidual cells, together with resident natural killer cells, dendritic cells, Hofbauer cells and other macrophages, among other cell types, contribute to the modulation of the uterine environment to sustain a successful pregnancy. In this review, the authors outlined some of the various roles that the innate immune system plays at the maternal-fetal interface. First, the cell populations that are recruited into gestational tissues and their immune mechanisms were examined. In the second part, the Toll-like receptor (TLR)-dependent immune responses at the maternal-fetal interface was summarized, in terms of their specific cytokine/chemokine/antimicrobial peptide expression profiles throughout pregnancy.

Obesity Is Associated with Changes in Iron Nutrition Status and Its Homeostatic Regulation in Pregnancy.

The influence of obesity on maternal iron homeostasis and nutrition status during pregnancy remains only partially clarified. Our study objectives were (1) to describe how obesity influences broad iron nutrition spectrum biomarkers such as available or circulating iron (serum transferrin receptor (sTfr) and serum iron), iron reserves (ferritin), and functional iron (hemoglobin); and (2) to depict the regulating role of hepcidin. The above was carried out while considering influential factors such as initial iron nutrition status, iron intake, and the presence of inflammation. Ninety three non-anemic pregnant adult women were included, 40 with obesity (Ob) and 53 with adequate weight (AW); all took ≈30 mg/day of supplementary iron. Information on iron intake and blood samples were obtained at gestational weeks 13, 20, 27, and 35. A series of repeated measure analyses were performed using General Linear Models to discern the effect of obesity on each iron indicator; iron intake, hepcidin, and C-reactive protein were successively introduced as covariates. Available and circulating iron was lower in obese women: sTfr was higher (p = 0.07) and serum iron was lower (p = 0.01); and ferritin and hemoglobin were not different between groups. Hepcidin was higher in the Ob group (p = 0.01) and was a significant predictor variable for all biomarkers. Obesity during pregnancy dysregulates iron homeostasis, resembling "obesity hypoferremia".

Choriodecidual leukocytes display a unique gene expression signature in spontaneous labor at term.

Prior to and during the process of human labor, maternal circulating leukocytes infiltrate the maternal-fetal interface (choriodecidua) and become activated resembling choriodecidual leukocytes. Since, there is no evidence comparing maternal circulating and choriodecidual leukocytes, herein, we characterized their transcriptome and explored the biological processes enriched in choriodecidual leukocytes. From women undergoing spontaneous term labor we isolated circulating and choriodecidual leukocytes, performed microarray analysis (n = 5) and qRT-PCR validation (n = 9) and interaction network analysis with up-regulated genes. We found 270 genes up-regulated and only 17 genes down-regulated in choriodecidual leukocytes compared to maternal circulating leukocytes. The most up-regulated genes were CCL18, GPNMB, SEPP1, FN1, RNASE1, SPP1, C1QC, and PLTP. The biological processes enriched in choriodecidual leukocytes were cell migration and regulation of immune response, chemotaxis, and humoral immune responses. Our results show striking differences between the transcriptome of choriodecidual and maternal circulating leukocytes. Choriodecidual leukocytes are enriched in immune mediators implicated in the spontaneous process of labor at term.

A trypsin-based method for isolating leukocytes from human choriodecidua suitable for immunophenotyping and transcriptome studies.

Leukocytes found at the human maternal-fetal interface participate in the inflammatory process associated with both preterm and term labor; therein, effective methods for their isolation that allow further phenotypic and functional analyses are necessary. Leukocyte isolation is usually carried out through scraping or enzyme digestion of the choriodecidua, however both methods usually limit the use of downstream immunophenotyping or transcriptomic techniques. Here we describe an isolation method based on gentle trypsin digestion that yields a leukocyte-enriched cell mixture with high lymphocyte viability, although less viable myeloid cells. We show that the method does not compromise cell surface markers since isolated leukocytes are suitable for flow cytometry; and that high quality RNA can be obtained from these cells for qRT-PCR and microarray analyses.

Selective immuno-modulatory effect of prolactin upon pro-inflammatory response in human fetal membranes.

During pregnancy, prolactin (PRL) is a neuro-immuno-cytokine that contributes actively to the crosstalk between the immune and endocrine systems and, thus, to the creation of an immune-privileged milieu. This work aims to analyze the capacity of PRL to modulate the synthesis and secretion of pro-inflammatory markers associated with labor. Studies were conducted using human fetal membranes at term mounted in a model of two independent chambers. The choriodecidual region was stimulated with 500-ng/mL lipopolysaccharide (LPS), and the amnion and choriodecidual region were co-simulated with different concentrations of PRL that can arise during pregnancy: 250, 500, 1000, and 4000ng/mL. Following these co-treatments, the tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, and IL-10 levels were measured in both compartments. As expected, treatment with LPS induced all cytokines to increase. Co-stimulation with the highest tested concentration of PRL induced significant decreases in TNF-α in the choriodecidual region and IL-1ß in both regions of the fetal membranes. PRL did not modified the IL-6 and IL-10 secretion profile. These findings, coupled with clinical evidence, suggest that the high level of PRL in the amniotic cavity is involved the mechanism by which the fetal-placental unit regulates the equilibrium between pro- and anti-inflammatory modulators.

Decidualization Mediated by Steroid Hormones Modulates the Innate Immunity in Response to Group B Streptococcal Infection in vitro.

BACKGROUND: Decidual cells play a role in the modulation of the innate immune response to protect pregnancy against infection. Steroid hormones regulate the innate immune response in different tissues, and they are involved in several biological processes like decidualization. The aim of this study was to assess if steroid hormones modulate the innate immunity in endometrial stromal cells (ESCs) and decidual stromal cells (DSCs) in response to group B streptococcus (GBS) infection in vitro. METHODS: Primary cultures of ESC were differentiated into DSC using 36 nM estradiol + 300 nM progesterone, and both were infected with GBS overnight. Concentrations of pro- and anti-inflammatory mediators (interleukin [IL]-1ß, IL-6, tumor necrosis factor [TNF]-α, IL-10, and TGF-ß), chemokines (IL-8 and GCP-2), and human ß-defensins (HBD-1, HBD-2, and HBD-3) were measured in the culture supernatants. RESULTS: DSCs showed a significant increase in IL-6 (p < 0.05), TNF-α (p < 0.05), IL-10 (p < 0.01), and TGF-ß (p < 0.05) secretion after GBS infection, while these changes were not observed in infected ESCs. IL-8 and GCP-2 increased after GBS infection, regardless of decidualization. ß-Defensins 1-3 decreased (p < 0.05) in ESCs after GBS infection, and hormone decidualization preserved the secretion of these antimicrobial peptides. CONCLUSIONS: Decidualization mediated by steroid hormones balance the pro- and anti-inflammatory response at the maternal-fetal interface under infection conditions.

The potential role of prolactin as a modulator of the secretion of proinflammatory mediators in chorioamniotic membranes in term human gestation.

OBJECTIVE: To test the effect of prolactin (PRL) on expression of proinflammatory cytokines and matrix metallopeptidase 9 (MMP-9) in vitro. STUDY DESIGN: Tissue explants were incubated from 4 to 48 hours alone or in the presence of 500 ng/mL PRL, and mRNA expression in tissues and secretion of interleukin (IL)-1ß, tumor necrosis factor alpha (TNF-α), MMP-2, and MMP-9 was quantified. RESULTS: Fetal membranes secreted IL-1ß, TNF-α, and MMP-9 in culture with consistent low concentration during the first 24 hours and then increased progressively. The presence of PRL during explant incubation significantly decreased the patterns of IL-1ß, TNF-α and MMP-9 secretion along culture (P < .001). MMP-2 secretion was unaffected by PRL. The relative basal expression of IL-1ß mRNA (1.2 ± 0.87) was reduced by 80% in the presence of PRL after 32 hours of incubation of the membranes (P = .001). The expression of the TNF-α mRNA was not modified by the presence of PRL (0.06 ± 0.01) compared with the basal expression levels (0.05 ± 0.01). MMP-9 mRNA basal expression (0.018 ± 0.008) was significantly reduced (P = .001) in the presence of PRL after 32 hours (0.002 ± 0.0005). CONCLUSION: PRL may be a potential candidate as a key signal controlling the expression of signals related to the proinflammatory reaction associated with human labor.

Tissue-specific IL-10 secretion profile from term human fetal membranes stimulated with pathogenic microorganisms associated with preterm labor in a two-compartment tissue culture system.

OBJECTIVE: Interleukin (IL)-10 is a cytokine with anti-inflammatory properties that plays pivotal roles in immune recognition and maintenance of pregnancy, limiting the harmful effects of pro-inflammatory modulators. The aim of this work was to characterize the contribution of amnion and choriodecidua regions of the human fetal membranes in the production of IL-10 after selective stimulation with Candida albicans, Gardnerella vaginalis and Streptococcus agalactiae. METHODS: Pre-labor human fetal membranes were cultured in a two-compartment tissue culture system and stimulated with 1 × 10(6) CFU/ml of each pathogen added to either the amniotic or choriodecidual region or both. RESULTS: Candida albicans and G. vaginalis were the pathogens most effective in inducing IL-10 secretion, increasing 20 and 10 times, respectively, the levels of this cytokine in the choriodecidual compartment. Stimulation with S. agalactiae was effective only in the choriodecidual region, increasing two times IL-10 concentration. CONCLUSIONS: Synthesis and secretion of IL-10 in response to three different pathogens associated with intrauterine infection and preterm birth are differential and depend on the nature of the microorganism and initial contact region.

Progesterone elicits an inhibitory effect upon LPS-induced innate immune response in pre-labor human amniotic epithelium.

PROBLEM: Infection of human fetal membranes elicits secretion of pro-inflammatory modulators through its innate immune capacities. We investigated the effect of lipopolysacharide (LPS) and progesterone (P4) upon expression of TLR-4/MyD88, TNFα, IL-6, IL-8, IL-10, and HBD2 on the human amniotic epithelium. METHOD OF STUDY: Explants of the human amniotic epithelium were pre-treated with 0.01, 0.1, and 1.0 µM of P4; then cotreated with 1000 ng/mL LPS. TLR-4 was immuno-detected, and concentrations of MyD88, TNFα, IL-6, IL-8, IL-10, and HBD2 were quantified by ELISA. RESULTS: P4 significantly reduced the expression of LPS-induced TLR-4/MyD88. LPS increased the concentrations of TNFα, IL-6, IL-8, IL-10, and HBD2 by factors of 30-, eight, three, three, and fivefold, respectively. P4 at 1.0 µM was the most effective dose to blunt the secretion of TNFα, IL-6, and HBD-2. RU-486 blocks the effect of P4. CONCLUSION: P4 inhibited LPS-induced TLR-4/MyD88 and pro-inflammatory factors in the human amniotic epithelium. These results could explain partially how P4 can protect the amniotic region of fetal membranes and generate a compensatory mechanism that limits the secretion of pro-inflammatory modulators, which could jeopardize the immune privilege during pregnancy.

Housekeeping gene expression stability in reproductive tissues after mitogen stimulation.

BACKGROUND: Intrauterine infection during pregnancy can trigger a local inflammatory response leading to several complications, such as preterm labor. Many studies have used in vitro and in vivo models employing mitogens to induce the expression of the characteristic proinflammatory mediators triggered by infection. However, relative expression assays depend on the stability of housekeeping gene expression, which can vary depending on certain stimuli. In this study, we analyzed the stability and pairwise variation in the expression of GAPDH, ACTB and RNA18S1 in cultured reproductive tissues under mitogen stimulation. We used fetal membranes, placental villous and umbilical cord explants from patients with normal term pregnancies (>37 weeks of gestation), as well as myometrium and cervix explants from patients undergoing hysterectomies. Tissues were stimulated with lipopolysaccharide or phytohemagglutinin for 24 hours. We then analyzed the expression stability and the pairwise variation of GAPDH, ACTB and RNA18S1 from real time quantitative RT-PCR absolute threshold cycles (Cp) using geNorm software. RESULTS: In all of the tissues, the three housekeeping genes showed great stability under our experimental conditions. Pairwise variation analyses showed that only two reference genes are required for adequate normalization, GAPDH and ACTB being optimal in the cervix, fetal membranes and umbilical cord, while GAPDH and RNA18S1 are best for normalization in the placenta and myometrium. CONCLUSION: Our results show that GAPDH, ACTB and RNA18S1 are adequate references for gene expression normalization in reproductive tissues stimulated with mitogens in culture.

Evidence for a role for the adaptive immune response in human term parturition.

PROBLEM: Spontaneous labor at term involves leukocyte recruitment and infiltration into the choriodecidua; yet, characterization of these leukocytes and their immunological mediators is incomplete. The purpose of this study was to characterize the immunophenotype of choriodecidual leukocytes as well as the expression of inflammatory mediators in human spontaneous parturition at term. METHOD OF STUDY: Choriodecidual leukocytes were analyzed by FACS, immunohistochemistry, and RT-PCR in three different groups: (i) preterm gestation delivered for medical indications without labor; (ii) term pregnancy without labor; and (iii) term pregnancy after spontaneous labor. RESULTS: Two T-cell subsets of memory-like T cells (CD3(+) CD4(+) CD45RO(+) and CD3(+) CD4(-) CD8(-) CD45RO(+) cells) were identified in the choriodecidua of women who had spontaneous labor. Evidence for an extensive immune signaling network composed of chemokines (CXCL8 and CXCL10), chemokine receptors (CXCR1-3), cytokines (IL-1ß and TNF-α), cell adhesion molecules, and MMP-9 was identified in these cells during spontaneous labor at term. CONCLUSIONS: The influx of memory-like T cells in the choriodecidua and the evidence that they are active by producing chemokines and cytokines, and expressing chemokine receptors, cell adhesion molecules, and a matrix-degrading enzyme provides support for the participation of the adaptive immune system in the mechanisms of spontaneous parturition at term.

Tissue-specific human beta-defensins (HBD)-1, HBD-2 and HBD-3 secretion profile from human amniochorionic membranes stimulated with Candida albicans in a two-compartment tissue culture system.

BACKGROUND: During intrauterine infection, amniochorionic membranes represent a mechanical and immunological barrier against dissemination of infection. Human beta defensins (HBD)-1, HBD-2, and HBD-3 are key elements of innate immunity that represent the first line of defense against different pathogen microorganisms associated with preterm labor. The aim of this work was to characterize the individual contribution of the amnion (AMN) and choriodecidua (CHD) regions to the secretion of HBD-1, HBD-2 and HBD-3, after stimulation with Candida albicans. METHODS: Full-thickness human amniochorionic membranes were obtained after delivery by elective cesarean section from women at 37-40 wk of gestation with no evidence of active labor. The membranes were cultured in a two-compartment experimental model in which the upper compartment is delimited by the amnion and the lower chamber by the choriodecidual membrane. One million of Candida albicans were added to either the AMN or the CHD face or to both and compartmentalized secretion profiles of HBD-1, HBD-2, and HBD-3 were quantified by ELISA. Tissue immunolocalization was performed to detect the presence of HBD-1, -2, -3 in tissue sections stimulated with Candida albicans. RESULTS: HBD-1 secretion level by the CHD compartment increased 2.6 times (27.30 [20.9-38.25] pg/micrograms protein) when the stimulus with Candida albicans was applied only on this side of the membrane and 2.4 times (26.55 [19.4-42.5] pg/micrograms protein) when applied to both compartments simultaneously. HBD-1 in the amniotic compartment remained without significant changes. HBD-2 secretion level increased significantly in the CHD when the stimulus was applied only to this region (2.49 [1.49-2.95] pg/micrograms protein) and simultaneously to both compartments (2.14 [1.67- 2.91] pg/micrograms protein). When the stimulus was done in the amniotic compartment HBD-2 remained without significant changes in both compartments. HBD-3 remained without significant changes in both compartments regardless of the stimulation modality. Localization of immune-reactive forms of HBD-1, HBD-2, and HBD-3 was carried out by immunohistochemistry confirming the cellular origin of these peptides. CONCLUSION: Selective stimulation of amniochorionic membranes with Candida albicans resulted in tissue-specific secretion of HBD-1 and HBD-2, mainly in the CHD, which is the first region to become infected during an ascending infection.