The role of inflammation and infection in preterm birth

Yogurt consumption during pregnancy and preterm delivery in Mexican women: A prospective analysis of interaction with maternal overweight status

Preterm delivery is an important cause of perinatal morbidity and mortality, often precipitated by maternal infection or inflammation. Probiotic-containing foods, such as yogurt, may reduce systemic inflammatory responses. We sought to evaluate whether yogurt consumption during pregnancy is associated with decreased preterm delivery. We studied 965 women enrolled at midpregnancy into a clinical trial of prenatal docosahexaenoic acid supplementation in Mexico. Yogurt consumption during the previous 3 months was categorized as ≥5, 2-4, or <2 cups per week. Preterm delivery was defined as delivery of a live infant before 37 weeks gestation. We used logistic regression to evaluate the association between prenatal yogurt consumption and preterm delivery and examined interaction with maternal overweight status. In this population, 25.4%, 34.2%, and 40.4% of women reported consuming ≥5, 2-4, and <2 cups of yogurt per week, respectively. The prevalence of preterm delivery was 8.9%. Differences in preterm delivery were non-significant across maternal yogurt consumption groups; compared with women reporting <2 cups of yogurt per week, those reporting 2-4 cups of yogurt per week had adjusted odds ratio (aOR) for preterm delivery of 0.81 (95% confidence interval, CI [.46, 1.41]), and those reporting ≥5 cups of yogurt per week had aOR of 0.94 (95% CI [.51, 1.72]). The association between maternal yogurt consumption and preterm delivery differed significantly for nonoverweight women compared with overweight women (p for interaction = .01). Compared with nonoverweight women who consumed <2 cups of yogurt per week, nonoverweight women who consumed ≥5 cups of yogurt per week had aOR for preterm delivery of 0.24 (95% CI [.07, .89]). Among overweight women, there was no significant association. In this population, there was no overall association between prenatal yogurt consumption and preterm delivery. However, there was significant interaction with maternal overweight status; among nonoverweight women, higher prenatal yogurt consumption was associated with reduced preterm delivery.

Amniotic fluid neutrophils can phagocytize bacteria: A mechanism for microbial killing in the amniotic cavity

PROBLEM

Neutrophils are capable of performing phagocytosis, a primary mechanism for microbial killing. Intra-amniotic infection is characterized by an influx of neutrophils into the amniotic cavity. Herein, we investigated whether amniotic fluid neutrophils could phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection.

METHODS

Amniotic fluid neutrophils from women with intra-amniotic infection were visualized by transmission electron microscopy (n=6). The phagocytic activity of amniotic fluid neutrophils from women with intra-amniotic infection and/or inflammation (n=10) or peripheral neutrophils from healthy individuals (controls, n=3) was tested using ex vivo phagocytosis assays coupled with live imaging. Phagocytosis by amniotic fluid neutrophils was also visualized by confocal microscopy (n=10) as well as scanning and transmission electron microscopy (n=5).

RESULTS

(i) Intra-amniotic infection-related bacteria including cocci (eg Streptococcus agalactiae), bacilli (eg Bacteriodes fragilis and Prevotella spp.), and small bacteria without a cell wall (eg Ureaplasma urealyticum) were found inside of amniotic fluid neutrophils; (ii) peripheral neutrophils (controls) rapidly phagocytized S. agalactiae, U. urealyticum, Gardnerella vaginalis, and Escherichia coli; (iii) amniotic fluid neutrophils rapidly phagocytized S. agalactiae and G. vaginalis; and (iv) amniotic fluid neutrophils slowly phagocytized U. urealyticum and E. coli; yet, the process of phagocytosis of the genital mycoplasma was lengthier.

CONCLUSION

Amniotic fluid neutrophils can phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection, namely S. agalactiae, U. urealyticum, G. vaginalis, and E. coli. Yet, differences in the rapidity of phagocytosis were observed among the studied microorganisms. These findings provide a host defense mechanism whereby amniotic fluid neutrophils can kill microbes invading the amniotic cavity.

Clinical chorioamnionitis at term VII: the amniotic fluid cellular immune response

OBJECTIVES

1) To characterize the cellular composition of the amniotic fluid of patients diagnosed with clinical chorioamnionitis at term, as a function of the presence or absence of microorganisms determined by cultivation techniques, and 2) to characterize the cytokine production by white blood cells present in the amniotic fluid using flow cytometry-based techniques.

MATERIALS AND METHODS

Amniotic fluid samples from 20 women who had the diagnosis of clinical chorioamnionitis at term were analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital Mycoplasmas). Amniotic fluid IL-6 concentrations were determined by an enzyme-linked immunosorbent assay. Amniotic fluid leukocytes were visualized by using hematoxylin and eosin staining and immunofluorescence. Immunophenotyping of surface markers and cytokines was performed in amniotic fluid leukocytes using flow cytometry.

RESULTS

1) Neutrophils (CD45+CD15+ cells) were the most common leukocyte subset found in the amniotic fluid, followed by monocytes (CD45+CD14+ cells); other white blood cells (such as lymphocytes and natural killer cells) were scarce in the amniotic fluid; 2) the absolute counts of neutrophils and monocytes were significantly higher in patients with microorganisms found in the amniotic fluid than in those without detectable microorganisms, using cultivation techniques; 3) there was a significant correlation between the absolute counts of neutrophils and monocytes determined by flow cytometry (Spearman's correlation=0.97; P<0.001); 4) there was a significant correlation between the absolute white blood cell count determined with a hemocytometer chamber and by flow cytometric analysis (Spearman's correlation=0.88; P<0.001); and 5) the profile of cytokine expression differed between monocytes and neutrophils; while neutrophils predominantly produced TNF-α and MIP-1β, monocytes expressed higher levels of IL-1β and IL-1α.

CONCLUSION

Flow cytometry analysis of the amniotic fluid of patients with intra-amniotic infection and clinical chorioamnionitis at term demonstrated that neutrophils and monocytes are the most common cells participating in the inflammatory process. We have characterized, for the first time, the differential cytokine expression by these cells in this important complication of pregnancy.

Environmental risk factors for autism: an evidence-based review of systematic reviews and meta-analyses

BACKGROUND

According to recent evidence, up to 40-50% of variance in autism spectrum disorder (ASD) liability might be determined by environmental factors. In the present paper, we conducted a review of systematic reviews and meta-analyses of environmental risk factors for ASD. We assessed each review for quality of evidence and provided a brief overview of putative mechanisms of environmental risk factors for ASD.

FINDINGS

Current evidence suggests that several environmental factors including vaccination, maternal smoking, thimerosal exposure, and most likely assisted reproductive technologies are unrelated to risk of ASD. On the contrary, advanced parental age is associated with higher risk of ASD. Birth complications that are associated with trauma or ischemia and hypoxia have also shown strong links to ASD, whereas other pregnancy-related factors such as maternal obesity, maternal diabetes, and caesarian section have shown a less strong (but significant) association with risk of ASD. The reviews on nutritional elements have been inconclusive about the detrimental effects of deficiency in folic acid and omega 3, but vitamin D seems to be deficient in patients with ASD. The studies on toxic elements have been largely limited by their design, but there is enough evidence for the association between some heavy metals (most important inorganic mercury and lead) and ASD that warrants further investigation. Mechanisms of the association between environmental factors and ASD are debated but might include non-causative association (including confounding), gene-related effect, oxidative stress, inflammation, hypoxia/ischemia, endocrine disruption, neurotransmitter alterations, and interference with signaling pathways.

CONCLUSIONS

Compared to genetic studies of ASD, studies of environmental risk factors are in their infancy and have significant methodological limitations. Future studies of ASD risk factors would benefit from a developmental psychopathology approach, prospective design, precise exposure measurement, reliable timing of exposure in relation to critical developmental periods and should take into account the dynamic interplay between gene and environment by using genetically informed designs.

Synergistic effect of DDT and its metabolites in lipopolysaccharide-mediated TNF-α production is inhibited by progesterone in peripheral blood mononuclear cells

Increased TNF-α levels have been associated with adverse pregnancy outcomes. Lipopolysaccharide (LPS), 1,1,1-trichloro-2,2-bis-(chlorophenyl)ethane (DDT), 1,1-bis-(chlorophenyl)-2,2-dichloroethene (DDE), and 1,1-dichloro-2,2-bis(chlorophenyl)ethane (DDD) induce TNF-α release in peripheral blood mononuclear cells (PBMC). Conversely, progesterone (P4) inhibits TNF-α secretion. Pregnant women in malaria endemic areas may be co-exposure to these compounds. Thus, this study was to investigate the synergistic effect of LPS and these pesticides in PBMC and to assess P4 influence on this synergy. Cultured PBMC were exposed to each pesticide in the presence of LPS, P4, or their combination. TNF-α was measured by ELISA. All pesticides enhanced TNF-α synthesis in PBMC. Co-exposure with LPS synergizes TNF-α production, which is blocked by progesterone. These results indicate that these organochlorines act synergistically with LPS to induce TNF-α secretion in PBMC. This effect is blocked by P4.

The Microbiome and Complement Activation: A Mechanistic Model for Preterm Birth

Preterm birth (PTB, <37 completed weeks' gestation) is one of the leading obstetrical problems in the United States, affecting approximately one of every nine births. Even more concerning are the persistent racial disparities in PTB, with particularly high rates among African Americans. There are several recognized pathophysiologic pathways to PTB, including infection and/or exaggerated systemic or local inflammation. Intrauterine infection is a causal factor linked to PTB thought to result most commonly from inflammatory processes triggered by microbial invasion of bacteria ascending from the vaginal microbiome. Trials to treat various infections have shown limited efficacy in reducing PTB risk, suggesting that other complex mechanisms, including those associated with inflammation, may be involved in the relationship between microbes, infection, and PTB. The complement system, a key mediator of the inflammatory response, is an innate defense mechanism involved in both normal physiologic processes that occur during pregnancy implantation and processes that promote the elimination of pathogenic microbes. Recent research has demonstrated an association between this system and PTB. The purpose of this article is to present a mechanistic model of inflammation-associated PTB, which hypothesizes a relationship between the microbiome and dysregulation of the complement system. Exploring the relationships between the microbial environment and complement biomarkers may elucidate a potentially modifiable biological pathway to PTB.

Maternal Influenza Immunization and Adverse Birth Outcomes: Using Data and Practice to Inform Theory and Research Design

Maternal influenza immunization can reduce influenza-attributable morbidity and mortality among pregnant women and infants who are too young to be vaccinated. Data from empirical studies also support the hypothesis that immunization can protect the fetus against adverse outcomes if the mother is exposed to influenza. In their theoretical analysis in the Journal, Hutcheon et al. (Am J Epidemiol 2016;184(3):227-232) critiqued the existing evidence of the fetal benefits of maternal influenza immunization by calculating the sample sizes needed to demonstrate hypothetical reductions in risk and concluded that the benefits observed in empirical studies are likely implausible. However, in their analysis, they did not take into account multiple fundamental characteristics of influenza epidemiology, including the time-variable effects of influenza illness and vaccination during pregnancy, or well-known differences in disease epidemiology between seasons, populations, and geographic regions. Although these and other factors might affect the magnitude of fetal benefit conferred by maternal influenza immunization, studies in which investigators have accounted for influenza circulation have demonstrated a consistent protective effect against a variety of adverse birth outcomes; those studies include the only randomized controlled trial designed a priori and adequately powered to do so. Only a comprehensive and nuanced assessment of the evidence base will allow for effective translation of these data into a global immunization policy.

Inhibition of Uterine Contractility by Thalidomide Analogs via Phosphodiesterase-4 Inhibition and Calcium Entry Blockade

Uterine relaxation is crucial during preterm labor. Phosphodiesterase-4 (PDE-4) inhibitors have been proposed as tocolytics. Some thalidomide analogs are PDE-4 inhibitors. The aim of this study was to assess the uterus-relaxant properties of two thalidomide analogs, methyl 3-(4-nitrophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4NO2PDPMe) and methyl 3-(4-aminophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4APDPMe) and were compared to rolipram in functional studies of spontaneous phasic, K⁺-induced tonic, and Ca²⁺-induced contractions in isolated pregnant human myometrial tissues. The accumulation of cAMP was quantified in HeLa cells. The presence of PDE-4B2 and phosphorylated myosin light-chain (pMLC), in addition to the effect of thalidomide analogs on oxytocin-induced pMLC, were assessed in human uterine myometrial cells (UtSMCs). Thalidomide analogs had concentration-dependent inhibitory effects on spontaneous and tonic contractions and inhibited Ca²⁺-induced responses. Tonic contraction was equipotently inhibited by 4APDPMe and rolipram (IC₅₀ = 125 ± 13.72 and 98.45 ± 8.86 µM, respectively). Rolipram and the thalidomide analogs inhibited spontaneous and tonic contractions equieffectively. Both analogs increased cAMP accumulation in a concentration-dependent manner (p < 0.05) and induced changes in the subcellular localization of oxytocin-induced pMLC in UtSMCs. The inhibitory effects of thalidomide analogs on the contractions of pregnant human myometrium tissue may be due to their PDE-4 inhibitory effect and novel mechanism as calcium-channel blockers.

CDC Grand Rounds: Public Health Strategies to Prevent Preterm Birth

Preterm birth (delivery before 37 weeks and 0/7 days of gestation) is a leading cause of infant morbidity and mortality in the United States. In 2013, 11.4% of the nearly 4 million U.S. live births were preterm; however, 36% of the 8,470 infant deaths were attributed to preterm birth (1). Infants born at earlier gestational ages, especially <32 0/7 weeks, have the highest mortality (Figure) and morbidity rates. Morbidity associated with preterm birth includes respiratory distress syndrome, necrotizing enterocolitis, and intraventricular hemorrhage; longer-term consequences include developmental delay and decreased school performance. Risk factors for preterm delivery include social, behavioral, clinical, and biologic characteristics (Box). Despite advances in medical care, racial and ethnic disparities associated with preterm birth persist. Reducing preterm birth, a national public health priority (2), can be accomplished by implementing and monitoring strategies that target modifiable risk factors and populations at highest risk, and by providing improved quality and access to preconception, prenatal, and interconception care through implementation of strategies with potentially high impact.

Regulatory Cytokine Expression and Preterm Birth: Case-Control Study Nested in a Cohort

Background

Currently known risk factors explain only a small fraction of preterm birth (PTB). Previous PTB is one of the most important predictors. However, this information is not available in primiparous women. Few studies have looked at associations between regulatory cytokine expression (RCE) and PTB and the results are conflicting.

Objective

To investigate the association of RCE–Interleukin 10 (IL-10) and Transforming Growth Factor β (TGF-β)–with PTB, and to assess whether bacterial vaginosis (BV) is involved in this relationship.

Methods

This was a case-control study nested in a prospective cohort–called BRISA. Women with singleton pregnancies were interviewed from 22 to 25 weeks of gestational age (GA). Women were recruited from health services in São Luís, Brazil. A blood sample was collected and gynecological examination was performed. Serum IL-10 and TGF-β were determined using cytometric bead array. Nugent score >7 and/or the presence of clue cells were used for BV diagnosis. All PTB estimated by ultrasound dating performed before 20 weeks of gestational age were considered cases. Controls were selected by simple random sampling from the rest of the cohort, at a 2:1 ratio. Different models were tested, according to the main independent variable. Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated by regression analyses.

Results

The study included 327 pregnant women, 109 cases and 218 controls. No associations were found between BV and PTB (P = 1.44; 95%CI: 0.51–3.77). Low levels of IL-10 (OR = 2.92 95%CI: 1.38–6.16) or TGF-β (OR = 16.90 95%CI: 6.42–44.51) or both simultaneously (OR = 77.16 95%CI: 7.99–744.88) were associated with increasing odds of PTB, even after adjustment for confounding.

Conclusion

Decreased RCE is a risk factor for PTB. This relationship, however, is not triggered by the presence of BV. Low IL-10/TGF-β levels from 22 to 25 weeks of GA could be used as early predictors of PTB. We suggest monitoring of these RCE, especially among primiparous women, for whom history of previous PTB is not available.

Baby born too soon: an overview and the impact beyond the infection

Spontaneous preterm delivery, prematurity, and low birth weight due to prematurity account for a great part of neonatal morbidity and mortality. Inflammation may cause preterm labor, with the involvement of different mediators that produce diverse aspects of the inflammatory response. Although bacteria are considered to be the main trigger for intrauterine infection/inflammation, immunological factors also appear to be involved. Recently, molecular genetic studies have helped us better understand the underlying pathophysiologic processes. During mammalian pregnancy, maternal-fetal tolerance involves a number of immunosuppressive factors produced by placenta. Recently, placenta-derived exosomes have emerged as new immune regulators in the maternal immune tolerance. This review focuses on the specific immune parameters that become altered during human pregnancy, the identity and function of some immune modulators that have been best characterized to date, as well as a comprehensive evaluation of the pregnancy-associated mechanisms that downregulate proinflammatory immunity to a level sufficient to prevent the triggering of premature common pathway of labor and damage to developing organs.

Bacterial Hyaluronidase Promotes Ascending GBS Infection and Preterm Birth

Preterm birth increases the risk of adverse birth outcomes and is the leading cause of neonatal mortality. A significant cause of preterm birth is in utero infection with vaginal microorganisms. These vaginal microorganisms are often recovered from the amniotic fluid of preterm birth cases. A vaginal microorganism frequently associated with preterm birth is group B streptococcus (GBS), or Streptococcus agalactiae However, the molecular mechanisms underlying GBS ascension are poorly understood. Here, we describe the role of the GBS hyaluronidase in ascending infection and preterm birth. We show that clinical GBS strains associated with preterm labor or neonatal infections have increased hyaluronidase activity compared to commensal strains obtained from rectovaginal swabs of healthy women. Using a murine model of ascending infection, we show that hyaluronidase activity was associated with increased ascending GBS infection, preterm birth, and fetal demise. Interestingly, hyaluronidase activity reduced uterine inflammation but did not impact placental or fetal inflammation. Our study shows that hyaluronidase activity enables GBS to subvert uterine immune responses, leading to increased rates of ascending infection and preterm birth. These findings have important implications for the development of therapies to prevent in utero infection and preterm birth.

IMPORTANCE

GBS are a family of bacteria that frequently colonize the vagina of pregnant women. In some cases, GBS ascend from the vagina into the uterine space, leading to fetal injury and preterm birth. Unfortunately, little is known about the mechanisms underlying ascending GBS infection. In this study, we show that a GBS virulence factor, HylB, shows higher activity in strains isolated from cases of preterm birth than those isolates from rectovaginal swabs of healthy women. We discovered that GBS rely on HylB to avoid immune detection in uterine tissue, but not placental tissue, which leads to increased rates of fetal injury and preterm birth. These studies provide novel insight into the underlying mechanisms of ascending infection.

The Effect of Influenza Vaccination on Birth Outcomes in a Cohort of Pregnant Women in Lao PDR, 2014-2015

BACKGROUND

Some studies suggest that maternal influenza vaccination can improve birth outcomes. However, there are limited data from tropical settings, particularly Southeast Asia. We conducted an observational study in Laos to assess the effect of influenza vaccination in pregnant women on birth outcomes.

METHODS

We consented and enrolled a cohort of pregnant woman who delivered babies at 3 hospitals during April 2014-February 2015. We collected demographic and clinical information on mother and child. Influenza vaccination status was ascertained by vaccine card. Primary outcomes were the proportion of live births born small for gestational age (SGA) or preterm and mean birth weight. Multivariate models controlled for differences between vaccinated and unvaccinated women and influenza virus circulation.

RESULTS

We enrolled 5103 women (2172 [43%] were vaccinated). Among the 4854 who had a live birth, vaccinated women were statistically significantly less likely than unvaccinated women to have an infant born preterm during the period of high influenza virus circulation (risk ratio [RR] = 0.56, 95% confidence interval [CI], .45-.70), and the effect remained after adjusting for covariates (adjusted RR, 0.69; 95% CI, .55-.87). There was no effect of vaccine on mean birth weight. Vaccinated mothers had a statistically significant elevated risk of having an infant born SGA (adjusted RR, 1.25; 95% CI, 1.11–1.41).

CONCLUSIONS

In this observational study, we found indirect evidence of influenza vaccine safety during pregnancy, and women who received vaccine had a reduced risk of delivering a preterm infant during times of high influenza virus circulation. Vaccination may prevent 1 in 5 preterm births that occur during periods of high influenza circulation.

A Cross-Species Analysis of Animal Models for the Investigation of Preterm Birth Mechanisms

BACKGROUND

Spontaneous preterm birth is the leading cause of neonatal morbidity and mortality worldwide. The ability to examine the exact mechanisms underlying this syndrome in humans is limited. Therefore, the study of animal models is critical to unraveling the key physiologic mechanisms that control the timing of birth. The purpose of this review is to facilitate enhanced assimilation of the literature on animal models of preterm birth by a broad range of investigators.

METHODS

Using classical systematic and informatics search techniques of the available literature through 2012, a database of intact animal models was generated. Research librarians generated a list of articles using multiple databases. From these articles, a comprehensive list of Medical Subject Headings (MeSH) was created. Using mathematical modeling, significant MeSH descriptors were determined, and a MEDLINE search algorithm was created. The articles were reviewed for mechanism of labor induction categorized by species.

RESULTS

Existing animal models of preterm birth comprise specific interventions to induce preterm birth, as no animal model was identified that exhibits natural spontaneous preterm birth at an incidence comparable to that of the humans. A search algorithm was developed which when used results in a comprehensive list of agents used to induce preterm delivery in a host of animal species. The evolution of 3 specific animal models--sheep, mice, and rats--has demonstrated a clear shift in focus in the literature from endocrine to inflammatory agents of preterm birth induction.

CONCLUSION

The process of developing a search algorithm to provide efficient access to information on animal models of preterm birth illustrates the need for a more precise organization of the literature to allow the investigator to focus on distinctly maternal versus fetal outcomes.

Effects of antenatal lipopolysaccharide and postnatal hyperoxia on airway reactivity and remodeling in a neonatal mouse model

BACKGROUND

Antenatal inflammation and preterm birth are associated with the development of airway diseases such as wheezing and asthma. Utilizing a newborn mouse model, we assessed the effects of maternal inflammation and postnatal hyperoxia on the neonatal airway.

METHODS

Pregnant C57/Bl6 dams were injected with lipopolysaccharide (LPS) or saline on embryonic day 16. Offspring were placed in room air or hyperoxia (50% O2) for 7 d and then returned to normoxia. Airway mechanics, histology, and laser capture micro-dissection (LCM) were performed.

RESULTS

At postnatal day 21, maternal LPS- and 50% O2-exposed pups exhibited increased resistance and decreased compliance compared to 21% O2 pups; however their effects were not synergistic. LPS and hyperoxia each increased the thickness of airway smooth muscle (ASM), but not the airway epithelial layer. Structural changes were largely limited to the conducting airways. Upregulation of inflammatory markers in the lung was observed at birth. LCM revealed increased collagen-3, transforming growth factor β, and connective tissue growth factor expression with LPS and hyperoxia within the ASM layer.

CONCLUSION

These novel studies provide functional, structural, and molecular evidence that antenatal inflammation is detrimental to the developing airway. Exposure to moderate hyperoxia does not exacerbate LPS effects on the airway.

Outside-in? Acute fetal systemic inflammation in very preterm chronically catheterized sheep fetuses is not driven by cells in the fetal blood

BACKGROUND

The preterm birth syndrome (delivery before 37 weeks gestation) is a major contributor to the global burden of perinatal morbidity and death. The cause of preterm birth is complex, multifactorial, and likely dependent, at least in part, on the gestational age of the fetus. Intrauterine infection is frequent in preterm deliveries that occur at <32 weeks gestation; understanding how the fetus responds to proinflammatory insult will be an important step towards early preterm birth prevention. However, animal studies of infection and inflammation in prematurity commonly use older fetuses that possess comparatively mature immune systems.

OBJECTIVE

Aiming to characterize acute fetal responses to microbial agonist at a clinically relevant gestation, we used 92-day-old fetuses (62% of term) to develop a chronically catheterized sheep model of very preterm pregnancy. We hypothesized that any acute fetal systemic inflammatory responses would be driven by signaling from the tissues exposed to Escherichia coli lipopolysaccharide that is introduced into the amniotic fluid.

STUDY DESIGN

Eighteen ewes that were carrying a single fetus at 92 days of gestation had recovery surgery to place fetal tracheal, jugular, and intraamniotic catheters. Animals were recovered for 24 hours before being administered either intraamniotic E coli lipopolysaccharide (n = 9) or sterile saline solution (n = 9). Samples were collected for 48 hours before euthanasia and necroscopy. Fetal inflammatory responses were characterized by microarray analysis, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay.

RESULTS

Intraamniotic lipopolysaccharide reached the distal trachea within 2 hours. Lipopolysaccharide increased tracheal fluid interleukin-8 within 2 hours and generated a robust inflammatory response that was characterized by interleukin-6 signaling pathway activation and up-regulation of cell proliferation but no increases in inflammatory mediator expression in cord blood RNA.

CONCLUSIONS

In very preterm sheep fetuses, lipopolysaccharide stimulates inflammation in the fetal lung and fetal skin and stimulates a systemic inflammatory response that is not generated by fetal blood cells. These data argue for amniotic fluid-exposed tissues that play a key role in driving acute fetal and intrauterine inflammatory responses.

Copper metabolism domain-containing 1 represses the mediators involved in the terminal effector pathways of human labour and delivery

STUDY HYPOTHESIS

Does Copper Metabolism MURR1 Domain 1 (COMMD1) play a role in regulating the mediators involved in the terminal processes of human labour and delivery?

STUDY FINDING

COMMD1 plays a critical role in the termination of nuclear factor-κB (NF-κB) activity and the control of pro-inflammatory and pro-labour mediators.

WHAT IS KNOWN ALREADY

Inflammation and infection are the biggest aetiological factors associated with preterm birth. NF-κB drives the transcription of pro-inflammatory mediators involved in the terminal effector pathways of human labour and delivery. In non-gestational tissues, COMMD1 is a negative regulator of NF-κB-induced inflammation.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

The mRNA and/or protein level of COMMD1 was assessed in myometrium (n = 8 per group) and fetal membranes (n = 8 per group) obtained from term non-labouring and labouring women at term, and fetal membranes (n = 8 per group) at preterm with and without histological chorioamnionitis. Primary human myometrial cells were used to determine the effect of pro-inflammatory mediators on COMMD1 level, and the effect of COMMD1 small interfering RNA (siRNA) on pro-labour mediators. Statistical significance was ascribed to a P < 0.05.

MAIN RESULTS AND THE ROLE OF CHANCE

COMMD1 expression was significantly decreased with spontaneous term labour in myometrium; in fetal membranes with histologically confirmed chorioamnionitis and in myometrial cells treated with pro-inflammatory cytokines interleukin (IL)-1β and tumour necrosis factor (TNF)-α, the bacterial product fibroblast-stimulating lipopeptide and the viral double stranded RNA analogue polyinosinic polycytidilic acid. Loss-of-function studies revealed an increase in inflammation- and infection-induced TNF-α, IL-1α, IL-1β, IL-6, IL-8 and/or monocyte chemoattractant protein-1 mRNA abundance and/or release; and cyclo-oxygenase-2 mRNA level, release of prostaglandin (PG) F2α and mRNA level of the PGF2α receptor FP. In addition, siRNA knockdown of COMMD1 was associated with significantly increased NF-κB activation as evidenced by increased IL-1β-induced IκB-α protein degradation and NF-κB DNA binding activity.

LIMITATIONS, REASONS FOR CAUTION

The conclusions are based on in vitro experiments with cells isolated from myometrium. Animal models, however, will be required to establish whether COMMD1 activators can prevent spontaneous preterm birth in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

The control of COMMD1 activation may provide an alternative therapeutic strategy for reducing the release of pro-labour mediators in spontaneous preterm labour.

LARGE SCALE DATA

Not applicable.

STUDY FUNDING AND COMPETING INTERESTS

Associate Professor Martha Lappas is supported by a Career Development Fellowship from the National Health and Medical Research Council (NHMRC; grant no. 1047025). Additional funding was provided by the Medical Research Foundation for Women and Babies and the Mercy Research Foundation. The author has no conflict of interest.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Clinical chorioamnionitis at term IV: the maternal plasma cytokine profile

INTRODUCTION

Fever is a major criterion for clinical chorioamnionitis; yet, many patients with intrapartum fever do not have demonstrable intra-amniotic infection. Some cytokines, such as interleukin (IL)-1, IL-6, interferon-gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), can induce a fever. The objective of this study was to determine whether maternal plasma concentrations of cytokines could be of value in the identification of patients with the diagnosis of clinical chorioamnionitis at term who have microbial-associated intra-amniotic inflammation.

METHODS

A retrospective cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=41; cases) and women in spontaneous labor at term without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified into three groups according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS), and amniotic fluid IL-6 concentration: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. The maternal plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) The maternal plasma concentrations of pyrogenic cytokines (IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) were significantly higher in patients with clinical chorioamnionitis at term than in those with spontaneous term labor without clinical chorioamnionitis; 2) the maternal plasma concentrations of cytokines were not significantly different among the three subgroups of patients with clinical chorioamnionitis (intra-amniotic inflammation with and without detectable bacteria and those without intra-amniotic inflammation); and 3) among women with the diagnosis of clinical chorioamnionitis, but without evidence of intra-amniotic inflammation, the maternal plasma concentrations of pyrogenic cytokines were significantly higher than in patients with spontaneous labor at term. These observations suggest that a fever can be mediated by increased circulating concentrations of these cytokines, despite the absence of a local intra-amniotic inflammatory response.

CONCLUSIONS

1) The maternal plasma concentrations of pyrogenic cytokines (e.g. IL-1β, IL-2, IL-6, IFN-γ, and TNF-α) are higher in patients with intra-partum fever and the diagnosis of clinical chorioamnionitis at term than in those in spontaneous labor at term without a fever; and 2) maternal plasma cytokine concentrations have limited value in the identification of patients with bacteria in the amniotic cavity. Accurate assessment of the presence of intra-amniotic infection requires amniotic fluid analysis.

TLR3 activation increases chemokine expression in human fetal airway smooth muscle cells

Viral infections, such as respiratory syncytial virus and rhinovirus, adversely affect neonatal and pediatric populations, resulting in significant lung morbidity, including acute asthma exacerbation. Studies in adults have demonstrated that human airway smooth muscle (ASM) cells modulate inflammation through their ability to secrete inflammatory cytokines and chemokines. The role of ASM in the developing airway during infection remains undefined. In our study, we used human fetal ASM cells as an in vitro model to examine the effect of Toll-like receptor (TLR) agonists on chemokine secretion. We found that fetal ASM express multiple TLRs, including TLR3 and TLR4, which are implicated in the pathogenesis of respiratory syncytial virus and rhinovirus infection. Cells were treated with TLR agonists, polyinosinic-polycytidylic acid [poly(I:C)] (TLR3 agonist), lipopolysaccharide (TLR4 agonist), or R848 (TLR7/8 agonist), and IL-8 and chemokine (C-C motif) ligand 5 (CCL5) secretion were evaluated. Interestingly, poly(I:C), but neither lipopolysaccharide nor R848, increased IL-8 and chemokine (C-C motif) ligand 5 secretion. Examination of signaling pathways suggested that the poly(I:C) effects in fetal ASM involve TLR and ERK signaling, in addition to another major inflammatory pathway, NF-κB. Moreover, there are variations between fetal and adult ASM with respect to poly(I:C) effects on signaling pathways. Pharmacological inhibition suggested that ERK pathways mediate poly(I:C) effects. Overall, our data show that poly(I:C) initiates activation of proinflammatory pathways in developing ASM, which may contribute to immune responses to infection and exacerbation of asthma.

Implementing Mass Cytometry at the Bedside to Study the Immunological Basis of Human Diseases: Distinctive Immune Features in Patients with a History of Term or Preterm Birth

Single-cell technologies have immense potential to shed light on molecular and biological processes that drive human diseases. Mass cytometry (or Cytometry by Time Of Flight mass spectrometry, CyTOF) has already been employed in clinical studies to comprehensively survey patients' circulating immune system. As interest in the "bedside" application of mass cytometry is growing, the delineation of relevant methodological issues is called for. This report uses a newly generated dataset to discuss important methodological considerations when mass cytometry is implemented in a clinical study. Specifically, the use of whole blood samples versus peripheral blood mononuclear cells (PBMCs), design of mass-tagged antibody panels, technical and analytical implications of sample barcoding, and application of traditional and unsupervised approaches to analyze high-dimensional mass cytometry datasets are discussed. A mass cytometry assay was implemented in a cross-sectional study of 19 women with a history of term or preterm birth to determine whether immune traits in peripheral blood differentiate the two groups in the absence of pregnancy. Twenty-seven phenotypic and 11 intracellular markers were simultaneously analyzed in whole blood samples stimulated with lipopolysaccharide (LPS at 0, 0.1, 1, 10, and 100 ng mL(-1)) to examine dose-dependent signaling responses within the toll-like receptor 4 (TLR4) pathway. Complementary analyses, grounded in traditional or unsupervised gating strategies of immune cell subsets, indicated that the prpS6 and pMAPKAPK2 responses in classical monocytes are accentuated in women with a history of preterm birth (FDR<1%). The results suggest that women predisposed to preterm birth may be prone to mount an exacerbated TLR4 response during the course of pregnancy. This important hypothesis-generating finding points to the power of single-cell mass cytometry to detect biologically important differences in a relatively small patient cohort.

A point of care test for the determination of amniotic fluid interleukin-6 and the chemokine CXCL-10/IP-10

OBJECTIVE

Intra-amniotic inflammation is a mechanism of disease implicated in preterm labor, preterm prelabor rupture of membrane, cervical insufficiency, a short cervix, and idiopathic vaginal bleeding. Determination of interleukin (IL)-6 with immunoassays has been proven for more than two decades to be an excellent method for the detection of intra-amniotic inflammation. However, assessment of IL-6 for this indication has been based on immunoassays which are not clinically available, and this has been an obstacle for the implementation of this test in clinical practice. It is now possible to obtain results within 20 min with a point of care (POC) test which requires minimal laboratory support. This test is based on lateral flow-based immunoassay. The objective of this study was to compare amniotic fluid (AF) IL-6 and interferon-γ - inducible protein 10 (IP-10 or CXCL-10) concentrations determined using lateral flow-based immunoassay or POC test and standard enzyme-linked immunosorbent assay (ELISA) techniques.

MATERIAL AND METHODS

AF samples were collected from patients with singleton gestations and symptoms of preterm labor (n = 20). AF IL-6 and IP-10 concentrations were determined by lateral flow-based immunoassay and ELISA. Intra-amniotic inflammation was defined as AF IL-6 ≥ 2.6 ng/ml. AF IL-6 and IP-10 concentrations between two assays were compared.

RESULTS

(1) Lateral flow-based immunoassay POC AF IL-6 and IP-10 test results were strongly correlated with concentrations of this cytokine/chemokine determined by ELISA (Spearman's ρ = 0.92 and 0.83, respectively, both p < 0.0001); (2) AF IL-6 concentrations determined by the lateral flow-based immunoassay test were, on average, 30% lower than those determined by ELISA, and the median difference was statistically significant (p < 0.0001); and (3) in contrast, AF IP-10 concentrations determined by the lateral flow-based immunoassay test were, on average, only 7% lower than those determined by ELISA, and the median difference was not statistically significant (p = 0.81).

CONCLUSION

AF IL-6 and IP-10 concentrations determined using a lateral flow-based immunoassay POC are strongly correlated with concentrations determined by conventional ELISA. This justifies further studies about the diagnostic indices and predictive values of this POC test.

Social context of preterm delivery in France in 2011 and impact on short-term health outcomes: the EPIPAGE 2 cohort study

BACKGROUND

Low socio-economic context increases the risk of preterm delivery and may affect short-term outcomes in children born preterm. We described the social context of preterm delivery in France in 2011 and compared it with the general population of deliveries over the same period. We also studied how social context influenced pregnancy and delivery characteristics in the preterm population, and how it affected mortality and short-term morbidity in liveborn preterm children (<35 weeks).

METHODS

We created an individual socio-economic vulnerability index, derived from multiple correspondence analysis based on maternal social information in the French National Perinatal Survey (NPS-2010). Weighted coordinates were applied to families from the EPIPAGE 2 study, a population-based cohort of preterm infants born in 2011, to quantify the infant's exposure to socio-economic vulnerability. Multivariable logistic models were used to relate the socio-economic context to pregnancy and delivery characteristics, and to assess its impact on short-term outcomes of the infants.

RESULTS

Among mothers of preterm infants, gestational age decreased as socio-economic conditions worsened. In the most deprived group, women had more irregular pregnancy care, a higher prevalence of infection during pregnancy, and a lower rate of antenatal corticosteroid administration. The most deprived group was associated with a higher risk of severe morbidity for the preterm neonates.

CONCLUSION

Our results emphasise the need for a large population-based surveillance system to identify the most deprived mothers, and to propose appropriate follow-up and care to these women and their infants in order to enhance long-term health.

A possible role of aryl hydrocarbon receptor in spontaneous preterm birth

Preterm birth (PTB) is defined as birth before 37 weeks of gestation and is a leading cause of neonatal mortality and morbidity. To date, the etiology of spontaneous PTB (sPTB) remains unclear; however, intrauterine bacterial infection-induced inflammation is considered to be one of the major triggers. Aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor. Upon activation, AhR signaling mediates many biological processes. AhR is abundantly expressed in human placentas, primarily in trophoblasts, and several fetal organs and tissues. The activation of AhR signaling can modulate inflammatory responses via promoting production of pro-inflammatory cytokines by the placenta and fetal membranes. These cytokines could enhance expression and/or activity of cyclooxygenase-2 (COX2) in human trophoblasts and amniotic epithelia, which in turn stimulate synthesis and release of prostaglandins (PGs; e.g., PGE2 and PGF2α). Given the discovery of a number of natural and endogenous AhR ligands in human, we hypothesize that in a subset of patients with high AhR expression in placentas and fetal membranes, repeated exposure to these AhR ligands hyperactivates AhR, inducing hyperactivation of the cytokines/COX2/PGs pathway, resulting in myometrial contractions, ultimately leading to sPTB. We further hypothesize that hyperactivation of this AhR pathway can induce sPTB either directly or in synergy with the bacterial infection. Proof of this hypothesis may provide a novel mechanism underlying sPTB.

Activation of decidual invariant natural killer T cells promotes lipopolysaccharide-induced preterm birth

Invariant natural killer T (iNKT) cells are crucial for host defense against a variety of microbial pathogens, but the underlying mechanisms of iNKT cells activation by microbes are not fully explained. In this study, we investigated the molecular mechanisms of iNKT cell activation in lipopolysaccharide (LPS)-stimulated preterm birth using an adoptive transfer system and diverse neutralizing antibodies (Abs) and inhibitors. We found that adoptive transfer of decidual iNKT cells to LPS-stimulated iNKT cell deficient Jα18(-/-) mice that lack invariant Vα14Jα281T cell receptor (TCR) expression significantly decreased the time to delivery and increased the percentage of decidual iNKT cells. Neutralizing Abs against Toll-like receptor 4 (TLR-4), CD1d, interleukin (IL)-12 and IL-18, and inhibitors blocking the activation of nuclear factor κB (NF-κB), mitogen-activated protein kinase (MAPK) p38 and extracellular signal-regulated kinase (ERK) significantly reduced in vivo percentages of decidual iNKT cells, their intracellular interferon (IFN)-γ production and surface CD69 expression. In vitro, in the presence of the same Abs and inhibitors used as in vivo, decidual iNKT cells co-cultured with LPS-pulsed dendritic cells (DCs) showed significantly decreased extracellular and intracellular IFN-γ secretion and surface CD69 expression. Our data demonstrate that the activation of decidual iNKT cells plays an important role in inflammation-induced preterm birth. Activation of decidual iNKT cells also requires TLR4-mediated NF-κB, MAPK p38 and ERK pathways, the proinflammatory cytokines IL-12 and IL-18, and endogenous glycolipid antigens presented by CD1d.

Associations between urinary phenol and paraben concentrations and markers of oxidative stress and inflammation among pregnant women in Puerto Rico

Phenols and parabens are used in a multitude of consumer products resulting in ubiquitous human exposure. Animal and in vitro studies suggest that exposure to these compounds may be related to a number of adverse health outcomes, as well as potential mediators such as oxidative stress and inflammation. We examined urinary phenol (bisphenol A (BPA), triclosan (TCS), benzophenone-3 (BP-3), 2,4-dichlorophenol (24-DCP), 2,5-dichlorophenol (25-DCP)) and paraben (butyl paraben (B-PB), methyl paraben (M-PB), propyl paraben (P-PB)) concentrations measured three times during pregnancy in relation to markers of oxidative stress and inflammation among participants in the Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) project. Serum markers of inflammation (c-reactive protein (CRP), IL-1β, IL-6, IL-10, and tumor necrosis factor-α (TNF-α)) were measured twice during pregnancy (n=105 subjects, 187 measurements) and urinary markers of oxidative stress (8-hydroxydeoxyguanosine (OHdG) and isoprostane) were measured three times during pregnancy (n=54 subjects, 146 measurements). We used linear mixed models to assess relationships between natural log-transformed exposure and outcome biomarkers while accounting for within individual correlation across study visits. After adjustment for urinary specific gravity, study visit, maternal pre-pregnancy BMI, and maternal education, an interquartile range (IQR) increase in urinary BPA was associated with 21% higher OHdG (p=0.001) and 29% higher isoprostane (p=0.0002), indicating increased oxidative stress. The adjusted increase in isoprostane per IQR increase in marker of exposure was 17% for BP-3, 27% for B-PB, and 20% for P-PB (all p<0.05). An IQR increase in triclosan (TCS) was associated with 31% higher serum concentrations of IL-6 (p=0.007), a pro-inflammatory cytokine. In contrast, IQR increases in BP-3 and B-PB were significantly associated with 16% and 18% lower CRP, a measure of systemic inflammation. Our findings suggest that exposure to BPA, select parabens, and TCS during pregnancy may be related to oxidative stress and inflammation, potential mechanisms by which exposure to these compounds may influence birth outcomes and other adverse health effects, but additional research is needed.

Omega-3 polyunsaturated fatty acids enhance cytokine production and oxidative stress in a mouse model of preterm labor

OBJECTIVE

Omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplementation during pregnancy remains controversial. We sought to examine the effects of ω-3 PUFA on inflammation and oxidative stress in vitro and in vivo using a model of preterm labor.

METHODS

In vivo. Female Swiss Webster mice were fed a normal diet or a 5% fish oil (FO) diet for 3 weeks then mated with normal-fed males. On gestational day 15, dams were injected with either saline (n=10 per group) or lipopolysaccharide (LPS, intrauterine) (n=10 per group). Maternal plasma, amniotic fluid, placentas, and uteri were collected 4 h later and assessed for cytokines; maternal plasma and amniotic fluids were analyzed for oxidative stress. In vitro. RAW264.7 mouse macrophage-like cells were treated with either: vehicle, H2O2, docosahexaenoic acid (DHA), or eicosapentaenoic acid (EPA) (0, 0.1-100 μM) and analyzed for oxidative stress.

RESULTS

In vivo. Administration of the 5% FO diet enhanced LPS-induced cytokines in the placenta (P<0.05-0.01) and increased tumor necrosis factor-α in the uterus (P<0.05) and amniotic fluid (P<0.01) when compared to LPS-treated normal-fed animals. Maternal plasma obtained from FO-fed dams showed higher LPS-induced oxidative stress than control-fed animals (P<0.035). However, no differences in oxidative stress were observed in the amniotic fluid. In vitro. Treatment of macrophage-like cells with ω-3 PUFA significantly and dose-dependently increased oxidative stress (P<0.001-0.0001).

CONCLUSIONS

Supplementation with FO for prior to and during pregnancy significantly increased LPS-induced inflammation in the amniotic fluid, uterus, and placenta and significantly increased maternal systemic oxidative stress in vivo. Likewise, DHA and EPA induced oxidative stress in macrophage-like cells in vitro.

Antenatal pharmacokinetics and placental transfer of N-acetylcysteine in chorioamnionitis for fetal neuroprotection

OBJECTIVE

To determine the pharmacokinetics (PK) and placental transfer of intravenous (i.v.) N-acetylcysteine (NAC) in mothers with a clinical diagnosis of chorioamnionitis (CA) and determine the PK of i.v. NAC in their infants.

STUDY DESIGN

In this prospective, double-blind study i.v. NAC 100 mg/kg/dose or saline was administered within 4 hours of CA diagnosis to pregnant women ≥24 weeks' gestation and then every 6 hours until delivery. Maternal PK and placental transfer were determined with maternal blood and matched maternal and cord venous blood. Neonatal PK estimates were determined from i.v. NAC (12.5-25 mg/kg/dose) administered every 12 hours for 5 doses. Noncompartmental analyses were performed for maternal and neonatal PK estimates.

RESULTS

Eleven mothers (5 preterm, 6 near-term) and 12 infants (1 set of twins) received NAC. Maternal clearance (CL) of NAC was faster than in nonpregnant adults, with a terminal elimination half-life of 1.2 ± 0.2 hours. The NAC cord to maternal ratio was 1.4 ± 0.8, suggesting rapid placental transfer and slower rate of fetal CL. Neonatal PK estimates for near-term compared with preterm infants showed a significantly shorter terminal elimination half-life (5.1 vs 7.5 hours, respectively) and greater CL (53.7 vs 45.0 mL/h/kg, respectively).

CONCLUSIONS

Maternal CL and placental transfer of NAC was rapid, with umbilical cord concentrations frequently exceeding maternal concentrations. The administration of NAC to mothers with CA achieves predictable NAC plasma concentrations in the fetus, indicating that antenatal neuroprotection may be possible for these newborns at high risk for neuroinflammation.

Slit2 is decreased after spontaneous labour in myometrium and regulates pro-labour mediators

Preterm birth, a global healthcare problem, is commonly associated with inflammation. As Slit2 plays an emerging role in inflammation, the purpose of this study was to determine the effect of Slit2 on labour mediators in human gestational tissues. Slit2 mRNA and protein expression were assessed using qRT-PCR and immunohistochemistry in foetal membranes and myometrium obtained before and after labour. Slit2 silencing was achieved using siRNA in primary myometrial cells. Pro-inflammatory and pro-labour mediators were evaluated by qRT-PCR, ELISA and gelatin zymography. Slit2 mRNA and protein expression were found to be significantly lower in myometrium after labour onset. There was no effect of term or preterm labour on Slit2 expression in foetal membranes. Slit2 mRNA expression was decreased in myometrium treated with LPS and IL-1β. Slit2 siRNA in myometrial cells increased IL-1β-induced pro-inflammatory cytokine gene expression and release (IL-6 and IL-8), COX-2 expression and prostaglandin PGE2 and PGF2α release, and MMP-9 gene expression and pro MMP-9 release. There was no effect of Slit2 siRNA on IL-1β-induced NF-κB transcriptional activity. Our results demonstrate that Slit2 is decreased in human myometrium after labour and our knock-down studies describe an anti-inflammatory effect of Slit2 in myometrial cells.

Intrauterine Candida albicans infection elicits severe inflammation in fetal sheep

BACKGROUND

Preventing preterm birth and subsequent adverse neonatal sequelae is among the greatest clinical challenges of our time. Recent studies suggest a role for Candida spp. in preterm birth and fetal injury, as a result of their colonization of either the vagina and/or the amniotic cavity. We hypothesized that intraamniotic Candida albicans would cause a vigorous, acute fetal inflammatory response.

METHODS

Sheep carrying singleton pregnancies received single intraamniotic injections of either saline (control) or 10(7) colony-forming units C. albicans 1 or 2 d prior to surgical delivery and euthanasia at 124 ± 2 d gestation.

RESULTS

Colonization of the amniotic cavity by C. albicans resulted in a modest inflammatory response at 1 d and florid inflammation at 2 d, characterized by fetal thrombocytopenia, lymphopenia, and significant increases of inflammatory cytokines/chemokines in the fetal membranes skin, lung, and the amniotic fluid.

CONCLUSION

Acute colonization of the amniotic cavity by C. albicans causes severe intrauterine inflammation and fetal injury. C. albicans is a potent fetal pathogen that can contribute to adverse pregnancy outcomes.

Prenatal inflammation is associated with adverse neonatal outcomes

OBJECTIVE

The purpose of this study was to determine whether prenatal inflammation (as assessed by clinical chorioamnionitis, maternal temperature >38°C, or histologic chorioamnionitis) is associated with a composite adverse neonatal outcome.

STUDY DESIGN

We performed a prospective cohort study of women at 22 weeks to 33 weeks 6 days' gestation with symptoms of labor (April 2009 to March 2012). Relevant maternal and neonatal exposures and outcomes were recorded. Multivariable logistic regression was performed to determine the association between prenatal inflammation and neonatal outcomes that were controlled for potential confounders.

RESULTS

We analyzed 871 mother-infant pairs. The preterm birth rate was 42.0%. When we controlled for infant sex and modified the data by gestational age at delivery, prenatal inflammation remains a significant risk factor for adverse neonatal outcomes, despite advancing gestational age: clinical chorioamnionitis at 32 weeks' gestation (odds ratio [OR], 3.12; 95% confidence interval [CI], 1.02-9.52], at 36 weeks' gestation (OR, 8.88; 95% CI, 4.32-18.25), and at 40 weeks' gestation (OR, 25.30; 95% CI, 9.25-69.19); maternal temperature >38°C at 32 weeks' gestation (OR, 3.18; 95% CI, 0.66-15.42), at 36 weeks gestation (OR, 8.40; 95% CI, 3.60-19.61), and at 40 weeks gestation (OR, 22.19; 95% CI, 8.15-60.44); histologic chorioamnionitis at 32 weeks gestation (OR, 1.25; 95% CI, 0.64-2.46), at 36 weeks gestation (OR, 2.56; 95% CI, 1.54-4.23), and at 40 weeks gestation (OR, 5.23; 95% CI, 1.95-13.99).

CONCLUSION

The protective association with advancing gestational age is diminished when prenatal inflammation is present.

History of preterm birth and subsequent cardiovascular disease: a systematic review

A history of preterm birth (PTB) may be an important lifetime risk factor for cardiovascular disease (CVD) in women. We identified all peer-reviewed journal articles that met study criteria (English language, human studies, female, and adults ≥19 years old), that were found in the PubMed/MEDLINE databases, and that were published between Jan. 1, 1995, and Sept. 17, 2012. We summarized 10 studies that assessed the association between having a history of PTB and subsequent CVD morbidity or death. Compared with women who had term deliveries, women with any history of PTB had increased risk of CVD morbidity (variously defined; adjusted hazard ratio [aHR] ranged from 1.2-2.9; 2 studies), ischemic heart disease (aHR, 1.3-2.1; 3 studies), stroke (aHR, 1.7; 1 study), and atherosclerosis (aHR, 4.1; 1 study). Four of 5 studies that examined death showed that women with a history of PTB have twice the risk of CVD death compared with women who had term births. Two studies reported statistically significant higher risk of CVD-related morbidity and death outcomes (variously defined) among women with ≥2 pregnancies that ended in PTBs compared with women who had at least 2 births but which ended in only 1 PTB. Future research is needed to understand the potential impact of enhanced monitoring of CVD risk factors in women with a history of PTB on risk of future CVD risk.

Sphingolipids in lung growth and repair

Sphingolipids comprise a class of bioactive lipids that are involved in a variety of pathophysiologic processes, including cell death and survival. Ceramide and sphingosine-1-phosphate (S1P) form the center of sphingolipid metabolism and determine proapoptotic and antiapoptotic balance. Findings in animal models suggest a possible pathophysiologic role of ceramide and S1P in COPD, cystic fibrosis, and asthma. Sphingolipid research is now focusing on the role of ceramides during lung inflammation and its regulation by sphingomyelinases. Recently, sphingolipids have been shown to play a role in the pathogenesis of bronchopulmonary dysplasia (BPD). Ceramide upregulation was linked with vascular endothelial growth factor suppression and decreased surfactant protein B levels, pathways important for the development of BPD. In a murine model of BPD, intervention with an S1P analog had a favorable effect on histologic abnormalities and ceramide levels. Ceramides and S1P also regulate endothelial permeability through cortical actin cytoskeletal rearrangement, which is relevant for the pathogenesis of ARDS. On the basis of these observations, the feasibility of pharmacologic intervention in the sphingolipid pathway to influence disease development and progression is presently explored, with promising early results. The prospect of new strategies to prevent and repair lung disease by interfering with sphingolipid metabolism is exciting and could potentially reduce morbidity and mortality in patients with severe lung disorders.

Maternal dietary docosahexaenoic acid supplementation attenuates fetal growth restriction and enhances pulmonary function in a newborn mouse model of perinatal inflammation

The preterm infant is often exposed to maternal and neonatal inflammatory stimuli and is born with immature lungs, resulting in a need for oxygen therapy. Nutritional intervention with docosahexaenoic acid (DHA; 6.3 g/kg of diet) has been shown to attenuate inflammation in various human diseases. Previous studies demonstrated that maternal DHA supplementation during late gestation and lactation attenuated hyperoxic lung injury in newborn mouse pups. In the present studies, we tested the hypothesis that DHA supplementation to the dam would reduce hyperoxic lung injury and growth deficits in a more severe model of systemic maternal inflammation, including lipopolysaccharide (LPS) and neonatal hyperoxia exposure. On embryonic day 16, dams were placed on DHA (6.3 g DHA/kg diet) or control diets and injected with saline or LPS. Diets were maintained through weaning. At birth, pups were placed in room air or hyperoxia for 14 d. Improvements in birth weight (P < 0.01), alveolarization (P ≤ 0.01), and pulmonary function (P ≤ 0.03) at 2 and 8 wk of age were observed in pups exposed to perinatal inflammation and born to DHA-supplemented dams compared with control diet-exposed pups. These improvements were associated with decreases in tissue macrophage numbers (P < 0.01), monocyte chemoattractant protein-1 expression (P ≤ 0.05), and decreases in soluble receptor for advanced glycation end products concentrations (P < 0.01) at 2 and 8 wk. Furthermore, DHA supplementation attenuated pulmonary fibrosis, which was associated with the reduction of matrix metalloproteinases 2, 3, and 8 (P ≤ 0.03) and collagen mRNA (P ≤ 0.05), and decreased collagen (P < 0.01) and vimentin (P ≤ 0.03) protein concentrations. In a model of severe inflammation, maternal DHA supplementation lessened inflammation and improved lung growth in the offspring. Maternal supplementation with DHA may be a therapeutic strategy to reduce neonatal inflammation.

Corticotropin-releasing hormone (CRH) promotes inflammation in human pregnant myometrium: the evidence of CRH initiating parturition?

CONTEXT

An increasing body of evidence indicates that human labor, either term or preterm, is an inflammatory event. CRH has been implicated to be a trigger of human parturition.

OBJECTIVE

To investigate whether CRH induces the cascades of inflammation in human pregnant myometrium, thereby leading to activation of uterus.

DESIGN

The myometrial tissues were obtained from pregnant women who were in labor or not in labor at term. The output of cytokines and prostaglandins (PGs) was determined by Multiplex and ELISA. Western blot analysis was used to determine the levels of uterine activation proteins (UAPs).

RESULTS

The levels of chemokines and cytokines as well as activated nuclear factor-κB (NF-κB) were increased in the term labor group more than the not term labor group. CRH stimulated production of a number of chemokines and cytokines in cultured uterine smooth muscle cells (USMCs), which induced chemotaxis of monocytes. These effects were mediated by CRH receptor 1 (CRHR1) and dependent on adenylyl cyclase/protein kinase (PKA) and NF-κB signaling. Cocultures of CRH-treated USMCs with monocytes greatly enhanced the output of cytokines and chemokines as well as PGs in cultures and increased the expression of uterine activation proteins (UAPs) in USMCs. IL-1β, IL-6, and TNF-α stimulated the expression of UAPs and output of PGs in USMCs.

CONCLUSIONS

CRH induces the production of chemokines and cytokines in myometrium at term and subsequently results in the cascade of inflammation in uterus. The inflammation induced by CRH can lead to activation of uterus.

Amniotic fluid metabolomic analysis in spontaneous preterm birth

OBJECTIVE

To identify metabolic changes associated with early spontaneous preterm birth (PTB; <34 weeks) and term births, using high-throughput metabolomics of amniotic fluid (AF) in African American population.

METHOD

In this study, AF samples retrieved from spontaneous PTB (<34 weeks [n = 25]) and normal term birth (n = 25) by transvaginal amniocentesis at the time of labor prior to delivery were subjected to metabolomics analysis. Equal volumes of samples were subjected to a standard solvent extraction method and analyzed using gas chromatography/mass spectrometry (MS) and liquid chromatography/MS/MS. Biochemicals were identified through matching of ion features to a library of biochemical standards. After log transformation and imputation of minimum observed values for each compound, t test, correlation tests, and false discovery rate corrections were used to identify differentially regulated metabolites. Data were controlled for clinical/demographic variables and medication during pregnancy.

RESULTS

Of 348 metabolites measured in AF samples, 121 metabolites had a gestational age effect and 116 differed significantly between PTB and term births. A majority of significantly altered metabolites could be classified into 3 categories, namely, (1) liver function, (2) fatty acid and coenzyme A (CoA) metabolism, and (3) histidine metabolism. The signature of altered liver function was apparent in many cytochrome P450-related pathways including bile acids, steroids, xanthines, heme, and phase II detoxification of xenobiotics with the largest fold change seen with pantothenol, a CoA synthesis inhibitor that was 8-fold more abundant in PTB.

CONCLUSION

Global metabolic profiling of AF revealed alteration in hepatic metabolites involving xenobiotic detoxification and CoA metabolism in PTB. Maternal and/or fetal hepatic function differences may be developmentally related and its contribution PTB as a cause or effect of PTB is still unclear.

WITHDRAWN: Special issue on Pregnancy and Steroids

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.jsbmb.2013.08.007. The duplicate article has therefore been withdrawn.

Tocolytic indomethacin: effects on neonatal haemodynamics and cerebral autoregulation in the preterm newborn

BACKGROUND

Indomethacin has vasoactive properties in cerebral and systemic vascular beds, and it improves cerebral autoregulatory ability. We speculated that tocolytic indomethacin will improve cerebral autoregulatory ability in the very preterm infant in early postnatal life.

METHODS

Eighteen stable preterm infants gestational age (GA) 25.3-29.6 weeks, birth weight (BW) 660-1430 grams), whose mothers had received 50-150 mg of tocolytic indomethacin within 24 h before birth, and 18 individually matched controls (GA 25.0-29.7 weeks, BW 700-1390 grams) were studied four times for 15 min in the first 24 h of life. Autoregulation was assessed by determining correlations between mean arterial blood pressure (MABP (mm Hg)) and near-infrared spectroscopy-monitored cerebral oxygenation (rScO2).

RESULTS

MABPs were significantly higher in the indomethacin infants than in the control infants (p=0.03). A decreased ability to autoregulate was found in four of the indomethacin infants, and in six of the control infants, which is not significantly different.

CONCLUSIONS

Prenatally administered indomethacin, given as a tocolytic in doses of 50-150 mg per day, improved transitional circulation in very preterm infants by significantly raising the MABP. It did not have an effect on the ability to autoregulate the cerebral circulation. In this study, no differences in short-term outcomes, like haemorrhagic or ischaemic cerebral lesions, were observed.

Selective exposure of the fetal lung and skin/amnion (but not gastro-intestinal tract) to LPS elicits acute systemic inflammation in fetal sheep

Inflammation of the uterine environment (commonly as a result of microbial colonisation of the fetal membranes, amniotic fluid and fetus) is strongly associated with preterm labour and birth. Both preterm birth and fetal inflammation are independently associated with elevated risks of subsequent short- and long-term respiratory, gastro-intestinal and neurological complications. Despite numerous clinical and experimental studies to investigate localised and systemic fetal inflammation following exposure to microbial agonists, there is minimal data to describe which fetal organ(s) drive systemic fetal inflammation. We used lipopolysaccharide (LPS) from E.coli in an instrumented ovine model of fetal inflammation and conducted a series of experiments to assess the systemic pro-inflammatory capacity of the three major fetal surfaces exposed to inflammatory mediators in pregnancy (the lung, gastro-intestinal tract and skin/amnion). Exposure of the fetal lung and fetal skin/amnion (but not gastro-intestinal tract) caused a significant acute systemic inflammatory response characterised by altered leucocytosis, neutrophilia, elevated plasma MCP-1 levels and inflammation of the fetal liver and spleen. These novel findings reveal differential fetal organ responses to pro-inflammatory stimulation and shed light on the pathogenesis of fetal systemic inflammation after exposure to chorioamnionitis.

Change in mononuclear leukocyte responsiveness in midpregnancy and subsequent preterm birth

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICAL TRIAL REGISTRATION

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

LEVEL OF EVIDENCE

II.

Fetal membrane biomarker network diversity and disease functions induced by intra-amniotic pathogens

PROBLEM

Intra-amniotic pathogens and by-products activate innate immune responses encompassing multitudes of signaling molecules and pathways that can result in spontaneous preterm birth (PTB). This study investigates fetal membrane response to bacterial stimulation using a bioinformatics approach.

METHOD OF STUDY

Dysregulated biomarker (IL1-β, IL-2, IL-8, IL-10, and TNF-α) data from fetal membranes at term stimulated with Ureaplasma urealyticum, Ureaplasma parvum, Mycoplasma hominis, E. coli, Group B Streptococci, Polyporhans gingivalis, or Gardnerella vaginalis with 50% (v/v) amniotic fluid (AF) were analyzed by Ingenuity Pathway Analysis.

RESULTS

In racially stratified analysis, networks representing late-stage immune inflammation were seen in African-Americans in AF absence. Inflammation was dominant in AF presence as well. In Caucasians, late-stage immune response was dominant with AF, but not in its absence.

CONCLUSIONS

Fetal membrane biofunctions in response to bacteria reflect early- and late-stage innate immune defenses that vary based on the presence of AF and subject race.

Can statins reduce the inflammatory response associated with preterm birth in an animal model?

OBJECTIVE

The objective of the study was to determine the effect of statins on lipopolysaccharide (LPS)-induced inflammatory response in a mouse model of preterm birth (PTB).

STUDY DESIGN

Day 15 CD1 mice were randomly allocated to intraperitoneal LPS injection (100 μg) or control. Mice in the LPS group were pretreated, 16 and 2 hours prior, with pravastatin (10 μg/g), simvastatin (10 μg/g), or vehicle control. Animals were sacrificed 6 hours after LPS. Cytokine messenger ribonucleic acid (mRNA) expression in the uterus and cervix, and concentrations in the maternal serum and amniotic fluid (AF) were determined.

RESULTS

Pravastatin reduced interleukin (IL)-1β and IL-6 mRNA expression in the uterus and cervix, respectively, and serum IL-1β and granulocyte-macrophage colony-stimulating factor (GM-CSF) concentrations. Simvastatin reduced IL-1β and IL-6 mRNA expressions in the uterus, IL-6 and tumor necrosis factor alpha (TNF-α) in the cervix, and IL-1β, IL-2, IL-12p70, IL-13, TNF-α, GM-CSF, and interferon-γ concentrations in the serum and IL-6 in AF.

CONCLUSION

Statins reduce the LPS-induced inflammatory responses in a mouse model of PTB.

Prenatal inflammation exacerbates hyperoxia-induced functional and structural changes in adult mice

Maternally derived inflammatory mediators, such as IL-6 and IL-8, contribute to preterm delivery, low birth weight, and respiratory insufficiency, which are routinely treated with oxygen. Premature infants are at risk for developing adult-onset cardiac, metabolic, and pulmonary diseases. Long-term pulmonary consequences of perinatal inflammation are unclear. We tested the hypothesis that a hostile perinatal environment induces profibrotic pathways resulting in pulmonary fibrosis, including persistently altered lung structure and function. Pregnant C3H/HeN mice injected with LPS or saline on embryonic day 16. Offspring were placed in room air (RA) or 85% O(2) for 14 days and then returned to RA. Pulmonary function tests, microCTs, molecular and histological analyses were performed between embryonic day 18 and 8 wk. Alveolarization was most compromised in LPS/O(2)-exposed offspring. Collagen staining and protein levels were increased, and static compliance was decreased only in LPS/O(2)-exposed mice. Three-dimensional microCT reconstruction and quantification revealed increased tissue densities only in LPS/O(2) mice. Diffuse interstitial fibrosis was associated with decreased micro-RNA-29, increased transforming growth factor-β expression, and phosphorylation of Smad2 during embryonic or early fetal lung development. Systemic maternal LPS administration in combination with neonatal hyperoxic exposure induces activation of profibrotic pathways, impaired alveolarization, and diminished lung function that are associated with prenatal and postnatal suppression of miR-29 expression.

The nonskeletal effects of vitamin D: an Endocrine Society scientific statement

Significant controversy has emerged over the last decade concerning the effects of vitamin D on skeletal and nonskeletal tissues. The demonstration that the vitamin D receptor is expressed in virtually all cells of the body and the growing body of observational data supporting a relationship of serum 25-hydroxyvitamin D to chronic metabolic, cardiovascular, and neoplastic diseases have led to widespread utilization of vitamin D supplementation for the prevention and treatment of numerous disorders. In this paper, we review both the basic and clinical aspects of vitamin D in relation to nonskeletal organ systems. We begin by focusing on the molecular aspects of vitamin D, primarily by examining the structure and function of the vitamin D receptor. This is followed by a systematic review according to tissue type of the inherent biological plausibility, the strength of the observational data, and the levels of evidence that support or refute an association between vitamin D levels or supplementation and maternal/child health as well as various disease states. Although observational studies support a strong case for an association between vitamin D and musculoskeletal, cardiovascular, neoplastic, and metabolic disorders, there remains a paucity of large-scale and long-term randomized clinical trials. Thus, at this time, more studies are needed to definitively conclude that vitamin D can offer preventive and therapeutic benefits across a wide range of physiological states and chronic nonskeletal disorders.