Differences in the placental membrane cytokine response: a possible explanation for the racial disparity in preterm birth

Decreased Adiponectin Levels in Early Pregnancy Are Associated with High Risk of Prematurity for African American Women

The relationship of low maternal serum adiponectin levels with preterm delivery among a multi-ethnic group has not been extensively investigated. We examined ethnic differences in cytokine/adipokine profiles and whether they contribute to several adverse pregnancy outcomes, particularly preterm delivery. Data and samples were from a large prospective observational cohort (n = 1776) of young, generally healthy pregnant women (African American 36.4%, Hispanic 48.0%, Caucasian 15.6%). Serum cytokine/adipokine concentrations were measured at entry (mean gestational age of 16.83 weeks) using the Liminex xMap Technology. Multivariable analyses were performed. A significant difference in adiponectin level was observed among ethnic groups. African Americans had a decreased adiponectin and increased resistin levels compared to Hispanics and Caucasians (p < 0.05 to p < 0.0001 for each). Decreased adiponectin (lowest quartile) was positively associated with preterm delivery independent of usual risk factors (adjusted odds ratio (AOR) 1.46, 95% confidence interval (CI) 1.05, 2.04 for all preterm and AOR 1.84, 95% CI 1.07, 3.17 for early preterm births). The results were unchanged when women with preeclampsia were excluded. Similar results were observed in African Americans. Decreased adiponectin levels were not related to preterm birth in either Hispanics or Caucasians. Lower adiponectin levels were also significantly associated with an increased risk of developing gestational diabetes (AOR 1.72, 95% CI 1.05, 2.84) and preeclampsia (AOR 1.45, 95% CI 1.00, 2.14) in the whole cohort and in Caucasians. We did not find any consistent relationships between the other markers with outcome variables. Dysregulation in maternal adiponectin at early gestation is associated with an increased risk of preterm delivery. An ethnic difference in adiponectin levels may contribute to a higher preterm delivery rate in African American women.

Prenatal particulate matter exposure and mitochondrial mutational load at the maternal-fetal interface: Effect modification by genetic ancestry

Prenatal ambient particulate matter (PM2.5) exposure impacts infant development and alters placental mitochondrial DNA abundance. We investigated whether the timing of PM2.5 exposure predicts placental mitochondrial mutational load using NextGen sequencing in 283 multi-ethnic mother-infant dyads. We observed increased PM2.5exposure, particularly during mid- to late-pregnancy and among genes coding for NADH dehydrogenase and subunits of ATP synthase, was associated with a greater amount of nonsynonymous mutations. The strongest associations were observed for participants of African ancestry. Further work is needed to tease out the role of mitochondrial genetics and its impact on offspring development and emerging disease disparities.

Understanding Racial Disparities of Preterm Birth Through the Placenta

The racial disparity associated with preterm birth is a public health concern in the United States. The placenta is the principal metabolic, respiratory, and endocrine organ of the fetus and a key route by which environmental exposures are transmitted from mother to offspring. Available at every delivery, it may serve as a marker of differences in prenatal exposures that manifest differently by race. Recently, we described differences in placental pathology between African-American and White preterm births: the prevalence of chronic inflammation was higher among African-American women's placentas compared with those of White women. Similarly, racial differences have been shown in placental malperfusion and placental weight. Social determinants such as poverty and stress from discrimination have been implicated in racial disparities in preterm birth. To date, however, the underlying biological mechanisms, whether through inflammatory, oxidative stress, or other pathways involving epigenetic programming, remain largely unknown. The placenta, complemented by maternal and umbilical cord blood biomarkers, may provide important information on the perinatal environment that explains the origins of racial disparities in preterm birth rates and subsequent health outcomes. This article reviews existing literature and current research gaps. Opportunities are discussed for future placental research that may reveal novel mechanisms leading to the development of new approaches in the prevention and management of preterm birth and its outcomes.

Fetal membrane extracellular vesicle profiling reveals distinct pathways induced by infection and inflammation in vitro

PROBLEM

Fetal inflammatory signals can be propagated to maternal tissues to initiate labor via exosomes (extracellular vesicles; 30-150 nm). We tested the hypothesis that fetal membrane cells exposed to infectious and inflammatory mediators associated with preterm birth (PTB) produce exosomes with distinct protein cargo contents indicative of underlying pathobiology.

METHODS OF STUDY

Fetal membrane explants (FM) as well as primary amnion epithelial (AEC) and mesenchymal cells (AMC), and chorion cells (CC) from term deliveries were maintained in normal conditions (control) or exposed to LPS 100 ng/mL or TNF-α 50 ng/mL for 48 hours. Exosomes were isolated from media by differential centrifugation and size exclusion chromatography and characterized using cryo-electron microscopy (morphology), nanoparticle tracking analysis (size and quantity), Western blot (markers), and mass spectroscopy (cargo proteins). Ingenuity pathway analysis (IPA) determined pathways indicated by differentially expressed proteins.

RESULTS

Irrespective of source or treatment, exosomes were spherical, had similar size, quantities, and markers (ALIX, CD63, and CD81). However, exosome cargo proteins were different between FM and individual fetal membrane cell-derived exosomes in response to treatments. Several common proteins were seen; however, there are several unique proteins expressed by exosomes from different cell types in response to distinct stimuli indicative of unique pathways and physiological functions in cells.

CONCLUSIONS

We demonstrate collective tissue and independent cell response reflected in exosomes in response to infectious and inflammatory stimuli. These cargoes determined underlying physiology and their potential in enhancing inflammation in a paracrine fashion.

Concepts in preterm birth research: Interview with a stakeholder

Preterm birth continues to be a clinical problem of vast significance all over the world [1,2]. The complexities of the biology of preterm birth suggest a syndrome with multiple factors that synchronize rupture of membranes, uterine contraction, cervical dilation, and labor. Multiple genetic, environmental, and basic biological factors are associated with preterm birth. Despite many years of effort, we still do not completely understand preterm birth, the basic mechanisms underlying parturition, or the relationship(s) between the two. My position has always been that breakthroughs in this area will come from an inclusive, integrative, and interdisciplinary approach that hears the voices of multiple stakeholders, encompasses "outside the box" thinking and utilizes novel methodologies. To document the voices of stakeholders, alternative thinking and the seeds of development of novel methodologies, I have begun to interview stakeholders in preterm birth. This is an interview with Ramkumar Menon, MS, PhD, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine & Perinatal Research, The University of Texas Medical Branch at Galveston. Dr. Menon is past president and current Executive Director of PREBIC Global. He has surmounted considerable challenges to not only produce outstanding science from his own laboratory, but also to bring together collaborators and support from all over the world to bear upon the problem of preterm birth. What follows is an interview I did with him in 2014.

Cognitive Behavioral Therapy for Insomnia and Women's Health: Sex as a Biological Variable

Differences in sleep for men and women begin at a very early age, with women reporting poorer sleep and having a higher risk for insomnia compared with men. Women are particularly vulnerable to developing insomnia during times of reproductive hormonal change. Sleep across the woman's lifespan and special treatment considerations for using cognitive behavioral therapy for insomnia (CBT-I) in women will be addressed in this review.

Spontaneous preterm birth: advances toward the discovery of genetic predisposition

Evidence from family and twin-based studies provide strong support for a significant contribution of maternal and fetal genetics to the timing of parturition and spontaneous preterm birth. However, there has been only modest success in the discovery of genes predisposing to preterm birth, despite increasing sophistication of genetic and genomic technology. In contrast, DNA variants associated with other traits/diseases have been identified. For example, there is overwhelming evidence that suggests that the nature and intensity of an inflammatory response in adults and children are under genetic control. Because inflammation is often invoked as an etiologic factor in spontaneous preterm birth, the question of whether spontaneous preterm birth has a genetic predisposition in the case of pathologic inflammation has been of long-standing interest to investigators. Here, we review various genetic approaches used for the discovery of preterm birth genetic variants in the context of inflammation-associated spontaneous preterm birth. Candidate gene studies have sought genetic variants that regulate inflammation in the mother and fetus; however, the promising findings have often not been replicated. Genome-wide association studies, an approach to the identification of chromosomal loci responsible for complex traits, have also not yielded compelling evidence for DNA variants predisposing to preterm birth. A recent genome-wide association study that included a large number of White women (>40,000) revealed that maternal loci contribute to preterm birth. Although none of these loci harbored genes directly related to innate immunity, the results were replicated. Another approach to identify DNA variants predisposing to preterm birth is whole exome sequencing, which examines the DNA sequence of protein-coding regions of the genome. A recent whole exome sequencing study identified rare mutations in genes encoding for proteins involved in the negative regulation (dampening) of the innate immune response (eg, CARD6, CARD8, NLRP10, NLRP12, NOD2, TLR10) and antimicrobial peptide/proteins (eg, DEFB1, MBL2). These findings support the concept that preterm labor, at least in part, has an inflammatory etiology, which can be induced by pathogens (ie, intraamniotic infection) or "danger signals" (alarmins) released during cellular stress or necrosis (ie, sterile intraamniotic inflammation). These findings support the notion that preterm birth has a polygenic basis that involves rare mutations or damaging variants in multiple genes involved in innate immunity and host defense mechanisms against microbes and their noxious products. An overlap among the whole exome sequencing-identified genes and other inflammatory conditions associated with preterm birth, such as periodontal disease and inflammatory bowel disease, was observed, which suggests a shared genetic substrate for these conditions. We propose that whole exome sequencing, as well as whole genome sequencing, is the most promising approach for the identification of functionally significant genetic variants responsible for spontaneous preterm birth, at least in the context of pathologic inflammation. The identification of genes that contribute to preterm birth by whole exome sequencing, or whole genome sequencing, promises to yield valuable population-specific biomarkers to identify the risk for spontaneous preterm birth and potential strategies to mitigate such a risk.

Biomarkers of spontaneous preterm birth: a systematic review of studies using multiplex analysis

OBJECTIVE

Despite decades of research on risk indicators of spontaneous preterm birth (PTB), reliable biomarkers are still not available to screen or diagnose high-risk pregnancies. Several biomarkers in maternal and fetal compartments have been mechanistically linked to PTB, but none of them are reliable predictors of pregnancy outcome. This systematic review was conducted to synthesize the knowledge on PTB biomarkers identified using multiplex analysis.

MATERIALS AND METHODS

Three electronic databases (PubMed, EMBASE and Web of Science) were searched for studies in any language reporting the use of multiplex assays for maternal biomarkers associated with PTB published from January 2005 to March 2014.

RESULTS

Retrieved citations (3631) were screened, and relevant studies (33) were selected for full-text reading. Ten studies were included in the review. Forty-two PTB-related proteins were reported, and RANTES and IL-10 (three studies) followed by MIP-1β, GM-CSF, Eotaxin, and TNF-RI (two studies) were reported more than once in maternal serum. However, results could not be combined due to heterogeneity in type of sample, study population, assay, and analysis methods.

CONCLUSION

By this systematic review, we conclude that multiplex assays are a potential technological advancement for identifying biomarkers of PTB, although no single or combination of biomarkers could be identified to predict PTB risk.

A proposed bio-panel to predict risk for spontaneous preterm birth among African American women

Preterm birth (PTB), or birth prior to 37 weeks gestation, impacts 11.5% of U.S. deliveries. PTB results in significant morbidity and mortality among affected children and imposes a large societal financial burden. Racial disparities in PTB are alarming. African American women are at more than 1.5 times the risk for PTB than white women. Unfortunately, the medical community's ability to predict who is at risk for PTB is extremely limited. History of a prior PTB remains the strongest predictor during a singleton gestation. Cervical length and fetal fibronectin measurement are helpful tools. However, usefulness is limited, particularly among the 95% of U.S. women currently pregnant and lacking a history of PTB. Therefore, preventive therapies do not reach a great number of women who may benefit from them. This manuscript, in response to the pressing need for predictors of PTB risk and elimination of racial disparities in PTB, presents a proposed bio-panel for use in predicting risk for spontaneous PTB among African American women. This bio-panel, measured each trimester, includes stimulated production of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-1 receptor antagonist (Ra), soluble(s) TNF receptor(R) 1, and sTNFR2, and cortisol responsiveness. We hypothesize that greater IL-1β and TNF-α production, decreased IL-1Ra, sTNFR1, and sTNFR2 production, and decreased cortisol responsiveness at each time point as well as a more expedient alignment with this unfavorable profile over time will be associated with PTB. The choice to focus on inflammatory parameters is supported by data highlighting a crucial role for inflammation in labor. Specific inflammatory mediators have been chosen due to their potential importance in preterm labor among African American women. The bio-panel also focuses on inflammatory regulation (i.e., cytokine production upon ex vivo stimulation), which is hypothesized to provide insight into potential in vivo leukocyte responses and potential for initiation of a preterm inflammatory cascade. Production of receptor antagonists is also considered, as pro-inflammatory mediator effects can be greatly influenced by their balance with respective antagonists. Finally, leukocyte responsiveness to cortisol is included as a measure of cortisol's ability to convey anti-inflammatory signals. The development of a bio-panel predictive of risk for spontaneous PTB among African American women would represent a significant advancement. Available preventive therapies, namely progesterone supplementation, could be delivered to women deemed at risk. Further, the identification of biological predictors of PTB may uncover novel targets for preventive therapies.

Racial/Ethnic Differences in Labor Outcomes with Prostaglandin Vaginal Inserts

OBJECTIVE

The aim of this study is to compare labor outcomes across race/ethnicity in women undergoing prostaglandin labor induction.

METHODS

Secondary analysis of misoprostol vaginal insert (MVI) trial, a double-blind, randomized, control trial of 1,308 patients comparing sustained release vaginal inserts containing dinoprostone 10 mg and misoprostol 50 mcg (MVI 50) or 100 mcg (MVI 100).

RESULTS

Achievement of active labor and induction failures were similar across race/ethnicity. Cesareans were performed less frequently in whites (29 %) and Hispanics (24.5 %) compared to blacks (32.7 %) (adjusted odds ratio (aOR) 0.87, 95 % confidence interval (CI) 0.47-0.97, p = 0.03 and aOR 0.86, 95 % CI 0.44-0.97, p = 0.03, respectively). When compared to blacks, whites were less likely to undergo cesarean for non-reassuring fetal heart rate tracing (aOR 0.41, 95 % CI 0.25-0.66, p = 0.0003), as were Hispanics (aOR 0.38, 95 % CI 0.22-0.65, p = 0.0004). Postpartum hemorrhage occurred more frequently in Hispanics (8.8 %) versus blacks (4.1 %) and whites (OR 2.27, 95 % CI 0.23-0.82, p = 0.02 and OR 3.69, 95 % CI 0.14-0.51, p < 0.0001, respectively). Birth weights of black infants were lower than whites (p < 0.0001) and Hispanics (p = 0.0003). Neonatal outcomes did not differ between groups.

CONCLUSION

Differences in labor induction outcomes with prostaglandin labor induction exist based on race/ethnicity. Blacks delivered smaller babies, were more likely to undergo cesarean, and have cesareans performed for non-reassuring fetal heart tracing compared to other groups. Hispanics were more likely to experience postpartum hemorrhage compared to the other races.

Pathway analysis of genetic factors associated with spontaneous preterm birth and pre-labor preterm rupture of membranes

Background

Pre-term birth (PTB) remains the leading cause of infant mortality and morbidity. Its etiology is multifactorial, with a strong genetic component. Genetic predisposition for the two subtypes, spontaneous PTB with intact membranes (sPTB) and preterm prelabor rapture of membranes (PPROM), and differences between them, have not yet been systematically summarised.

Methods and findings

Our literature search identified 15 association studies conducted in 3,600 women on 2175 SNPs in 274 genes. We used Ingenuity software to impute gene pathways and networks related to sPTB and PPROM. Detailed insight in the defined functional ontologies clearly separated integrated datasets for sPTB and PPROM. Our analysis of upstream regulators of genes suggests that glucocorticoid receptor (NR3C1), peroxisome proliferator activated receptor γ (PPARG) and interferon regulating factor 3 (IRF3) may be sPTB specific. PPROM-specific genes may be regulated by estrogen receptor2 (ESR2) and signal transducer and activator of transcription (STAT1). The inflammatory transcription factor NFκB is linked to both sPTB and PPROM, however, their inflammatory response is distinctly different.

Conclusions

Based on our analyses, we propose an autoimmune/hormonal regulation axis for sPTB, whilst pathways implicated in the etiology of PPROM include hematologic/coagulation function disorder, collagen metabolism, matrix degradation and local inflammation. Our hypothesis generating study has identified new candidate genes in the pathogenesis of PPROM and sPTB, which should be validated in large cohorts.

Human fetal membranes generate distinct cytokine profiles in response to bacterial Toll-like receptor and nod-like receptor agonists

Bacterial infection-associated inflammation is thought to be a major cause of preterm premature rupture of membranes. Proinflammatory cytokines, such as interleukin 1B (IL1B), can weaken fetal membranes (FM) by upregulating matrix metalloproteinases and inducing apoptosis. The mechanism by which infection leads to inflammation at the maternal-fetal interface and subsequent preterm birth is thought to involve innate immune pattern recognition receptors (PRR), such as the Toll-like receptors (TLR) and Nod-like receptors (NLR), which recognize pathogen-associated molecular patterns (PAMPs). The objective of this study was to determine the cytokine profile generated by FMs in response to the bacterial TLR and NLR agonists peptidoglycan (PDG; TLR2), lipopolysaccharide (LPS; TLR4), flagellin (TLR5), CpG ODN (TLR9), iE-DAP (Nod1), and MDP (Nod2). PDG, LPS, flagellin, iE-DAP, and MDP triggered FMs to generate an inflammatory response, but the cytokine profiles were distinct for each TLR and NLR agonist, and only IL1B and RANTES were commonly upregulated in response to all five PAMPs. CpG ODN, in contrast, had a mild stimulatory effect only on MCP-1 and primarily downregulated basal FM cytokine production. IL1B secretion induced by PDG, LPS, flagellin, iE-DAP, and MDP was associated with its processing. Furthermore, FM IL1B secretion in response to TLR2, TLR4, and TLR5 activation was caspase 1-dependent, whereas Nod1 and Nod2 induced IL1B secretion independent of caspase 1. These findings demonstrate that FMs respond to different bacterial TLR and NLR PAMPs by generating distinct inflammatory cytokine profiles through distinct mechanisms that are specific to the innate immune PRR activated.

Influence of infection during pregnancy on fetal development

Infection by bacteria, viruses, and parasites may lead to fetal death, organ injury, or limited sequelae depending on the pathogen. Here, we consider the role of infection during pregnancy in fetal development including placental development and function, which can lead to fetal growth restriction. The classical group of teratogenic pathogens is referred to as 'TORCH' (Toxoplasma gondii, others like Treponema pallidum, rubella virus, cytomegalovirus, and herpes simplex virus) but should include a much broader group of pathogens including Parvovirus B19, Varicella zoster virus, and Plasmodium falciparum to name a few. In this review, we describe the influence of different infections in utero on fetal development and the short- and long-term outcomes for the neonate. In some cases, the mechanisms used by these pathogens to disrupt fetal development are well known. Bacterial infection of the developing fetal lungs and brain begins with an inflammatory cascade resulting in cytokine injury and oxidative stress. For some pathogens like P. falciparum, the mechanisms involve oxidative stress and apoptosis to disrupt placental and fetal growth. An in utero infection may also affect the long-term health of the infant; in many cases, a viral infection in utero increases the risk of developing type 1 diabetes in childhood. Understanding the varied mechanisms employed by these pathogens may enable therapies to attenuate changes in fetal development, decrease preterm birth, and improve survival.

Factors associated with clinically significant insomnia among pregnant low-income Latinas

BACKGROUND

Poor sleep, common during pregnancy, is associated with negative health risks. The study aimed to identify predictors of clinically significant insomnia among pregnant Latinas.

METHODS

A total of 1289 pregnant Latinas recruited from obstetric clinics completed the Insomnia Severity Index (ISI) and questions about demographics and sleep.

RESULTS

Clinically significant insomnia (ISI≥10) was present among 17% of participants. Significant correlates of clinically significant insomnia were higher scores on the Edinburgh Postnatal Depression Scale (EPDS) after removing the sleep item (47% of women with EPDS≥9 and 9% with EPDS<9), completing measures in English (rather than Spanish: 26% versus 13%), and income but not pregnancy week, age, highest education level, or marital status. The highest percentage of clinically significant insomnia (59%) was experienced by women with EPDS≥9 who completed measures in English. The lowest percentage of clinically significant insomnia (6.2%) was experienced by women with EPDS<9 who completed measures in Spanish.

CONCLUSIONS

In this sample of low-income, mostly Spanish-speaking pregnant Latinas, rates of clinically significant insomnia appear to be higher than rates among nonpregnant Latinas. Rates of clinically significant insomnia are particularly high among Latinas with elevated depressive symptom severity, a known risk for insomnia. Acculturation, as indicated by completing measures in English, may be another risk specific to Latinas, possibly owing to loss of some ethnicity-specific protective factors (e.g., social support, strong family ties, and group identity). It will be important to directly test this explanation in future research.

Sleep and Women's Health

Sex differences in sleep begin at a very early age and women report poorer sleep quality and have higher risk for insomnia than do men. Sleep may be affected by variation in reproductive hormones, stress, depression, aging, life/role transitions, and other factors. The menstrual cycle is associated with changes in circadian rhythms and sleep architecture. Menstruating women (even without significant menstrual-related complaints) often report poorer sleep quality and greater sleep disturbance during the premenstrual week compared to other times of her menstrual cycle. In addition to these sleep disturbances, women with severe premenstrual syndrome often report more disturbing dreams, sleepiness, fatigue, decreased alertness and concentration during the premenstrual phase. Sleep disturbances are also commonly reported during pregnancy and increase in frequency and duration as the pregnancy progresses. The precipitous decline in hormones and unpredictable sleep patterns of the newborn contribute to and/or exacerbate poor sleep and daytime sleepiness during the early postpartum period. Insomnia is also among the most common health complaints that are reported by perimenopausal women. Women are particularly vulnerable to developing insomnia disorder during these times of reproductive hormonal change. In this review, we present a discussion on the most relevant and recent publications on sleep across the woman's lifespan, including changes in sleep related to menstruation, pregnancy, postpartum, and the menopausal transition. Treatment for sleep disturbances and insomnia disorder and special considerations for treating women will also be discussed.

Do pregnant women with depression have a pro-inflammatory profile?

AIM

We tested the hypothesis that maternal depression is associated with a pro-inflammatory state in pregnancy.

MATERIAL AND METHODS

In this nested case-control study, pro-inflammatory cytokine levels were compared between women with depression in pregnancy (n = 100) and a computer-generated referent group of healthy women known not to be depressed (n = 100). We only included cases with a documented Diagnostic and Statistical Manual of Mental Disorders depression diagnosis in the current pregnancy. Serum samples drawn at 11-14 weeks of gestation were analyzed for levels of tumor necrosis factor-alpha and interleukin-6 using high-sensitivity immunoassays.

RESULTS

Maternal demographics were similar between the groups except for older age (34.1 vs 32.7 years, P = .05), and lower body mass index (27.3 vs 28.9 kg/m², P = 0.03) among the depressed subjects. Compared to control women, tumor necrosis factor-alpha (5.8 ± 3.4 vs 3.2 ± 2.8 pg/ml, P < 0.0001) and interleukin-6 (2.4 ± 3.8 vs 1.5 ± 1.4 pg/ml, P = 0.03) levels were higher among women with depression. The higher rate of inflammatory cytokines remained significant after controlling for potential confounders, including maternal age and body mass index.

CONCLUSION

Women with depression may have higher levels of inflammatory markers in early pregnancy. Our findings support the hypothesis that inflammation may be a mediator in the association between maternal depression and adverse perinatal outcomes.

Lipopolysaccharide-induced murine embryonic resorption involves nitric oxide-mediated inhibition of the NAD+-dependent 15-hydroxyprostaglandin dehydrogenase

The initial inactivation of prostaglandins (PGs) is mediated by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). PGs are potent mediators of several biological processes, including inflammation and reproduction. In uterus, PGs play a key role in infection-induced pregnancy loss, in which concentration of this mediator increased. This process is accompanied with the induction of nitric oxide synthase expression and a marked increase in uterine levels of nitric oxide. There is no information concerning nitric oxide contribution to potential changes in PG catabolism, but experimental evidence suggests that nitric oxide modulates PG pathways. The specific objectives of the study were to evaluate the protein expression of HPGD (15-PGDH) and to characterize the nitric oxide-dependent regulation of this enzyme in a model of lipopolysaccharide (LPS)-induced embryonic resorption. Results show that LPS decreased HPGD protein expression and augmented PGE synthase activity; therefore, PGE2 levels increased in uterus in this inflammatory condition. Just as LPS, the treatment with a nitric oxide donor diminished HPGD protein expression in uterine tissue. In contrast, the inhibition of nitric oxide synthesis both in control and in LPS-treated mice increased 15-PGDH levels. Also, we have found that this enzyme and PGE2 levels are not modulated by peroxynitrite, an oxidant agent derived from nitric oxide. This study suggests that LPS and nitric oxide promote a decrease in the ability of the uterus for PG catabolism during bacterially triggered pregnancy loss in mice.

Non-pharmacological treatment of insomnia

Insomnia is one of the most common sleep disorders, which is characterized by nocturnal symptoms of difficulties initiating and/or maintaining sleep, and by daytime symptoms that impair occupational, social, or other areas of functioning. Insomnia disorder can exist alone or in conjunction with comorbid medical and/or psychiatric conditions. The incidence of insomnia is higher in women and can increase during certain junctures of a woman's life (e.g., pregnancy, postpartum, and menopause). This article will focus on an overview of cognitive behavioral therapy for insomnia, evidence of effectiveness for this treatment when insomnia disorder is experienced alone or in parallel with a comorbidity, and a review with promising data on the use of cognitive behavioral therapy for insomnia when present during postpartum and menopause.

Amniotic fluid and maternal race influence responsiveness of fetal membranes to bacteria

Spontaneous preterm birth (PTB) and preterm prelabor rupture of membranes (pPROM) occur more frequently in African-American women than in other racial groups. This may be due to an enhanced inflammatory response to pathogens associated with the condition. It is also possible that amniotic fluid (AF) has different immunomodulatory properties in African-American women that increase their risk of PTB and pPROM. To test this, we cultured fetal membranes from European-American and African-American women with sterile medium (control), Escherichia coli, Gardnerella vaginalis, Group B streptococci (GBS), Polyporphorans gingivalis, Mycoplasma hominis, Ureaplasma urealyticum or Ureaplasma parvum in the presence and absence of 50% autologous AF. Cytokine concentrations were quantified in the conditioned medium. All bacterial species increased IL-8 production. IL-1β and TNF-α production were stimulated by LPS, E. coli, and G. vaginalis compared with control, but responses to Group B streptococci and P. gingivalis were limited to IL-1β and TNF-α respectively. Genital mycoplasmas stimulated TNF-α and IL-10 but had no effect on IL-1β production. African-Americans had twice the IL-1β response to E. coli as European-Americans (P=0.031). Conversely, European-Americans produced more IL-8 in response to LPS than African-Americans (P=0.026). AF had both pro- and anti-inflammatory properties that varied between races and pathogens. These results suggest that the host response to fetal membrane infections is complex and not generalizable. Interventions to prevent PTB and pPROM may need to be customized based on a patient's race, type of bacterial infection and factors in her AF.

Changes in the levels of interleukins 6, 8, and 10, tumor necrosis factor alpha, and granulocyte-colony stimulating factor in Korean burn patients: relation to burn size and postburn time

Background

Major burn injury induces an inflammatory response that is accompanied by the release of various cytokines. We investigated the gradual changes in the levels of pro-inflammatory and anti-inflammatory cytokines following burn injury and determined the relationship between these levels and burn size in adult Korean patients with burn injury.

Methods

Blood samples from 9 healthy controls and 60 Korean burn patients were collected on days 1, 3, 7, 14, and 21 after burn injury, and concentrations of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, and granulocyte-colony stimulating factor (G-CSF) were measured. Burn patients were divided into 3 groups according to burn size (15-30%, 31-50%, >50% total body surface area), and the concentrations of the cytokines were compared between these groups and the control group over 3 weeks.

Results

Compared to their levels in controls, IL-6, IL-8, IL-10, TNF-α, and G-CSF levels in burn patients were significantly higher during the observation period. Median concentrations of IL-8, IL-10, and G-CSF at each time point increased with burn size, although peak levels and time to peak levels of these cytokines differed from patient to patient.

Conclusions

These findings indicate that IL-6, IL-8, IL-10, TNF-α, and G-CSF are important mediators in inflammatory changes after burn injury; however, various factors, including burn size, may influence the concentrations of these cytokines.

Second trimester maternal plasma levels of cytokines IL-1Ra, Il-6 and IL-10 and preterm birth

OBJECTIVE

To examine the interaction of the cytokines interleukin-1 receptor antagonist (IL)-1Ra, IL-6 and IL-10 to predict preterm birth (PTB) in pregnant Hispanic women (n=470).

STUDY DESIGN

In this prospective study, demographic data were obtained prenatally and birth outcome data were obtained from the medical chart. Cytokines were measured from plasma obtained at 22 to 24 weeks gestation. Data analysis utilized logistic regression.

RESULT

PTB was predicted by level of IL-1Ra (odds ratio (OR)=2.55; 95% confidence interval (CI)=1.24, 5.24). The interaction between IL-1Ra and IL-6 and between IL-1Ra and IL-10 was significant (Wald=4.01, P=0.04 and Wald=8.84, P<0.003, respectively) and was also predictive of PTB. As IL-1Ra levels increased while IL-10 levels were low, the probability of PTB greatly increased.

CONCLUSION

The interactions of select cytokines and cytokine receptor antagonists were associated with PTB. Future research should focus on the changes in cytokines during pregnancy to identify critical periods of change, and examine predictors of the cytokine response.

Male gender promotes an increased inflammatory response to lipopolysaccharide in umbilical vein blood

OBJECTIVES

To establish gender-specific differences in maternal and fetal immune response in healthy human fetuses at term.

METHODS

Forty-five women with elective caesarean sections for uncomplicated singleton pregnancies were recruited for two studies. Using a multiplex biomarker immunoassay system, unstimulated maternal and fetal plasma concentrations of interleukin (IL)-1β, IL-1ra, IL-6, IL-8, macrophage inflammatory protein (MIP)-1α, and tumor necrosis factor (TNF)-α were measured from one study population. Lipopolysaccharide (LPS)-stimulated cytokine response was measured in a second study.

RESULTS

There were no significant gender differences in either maternal or fetal unstimulated plasma cytokine concentrations, but concentrations of the proinflammatory cytokines IL-1β and IL-6 were significantly greater in male fetal LPS-stimulated samples than in female fetal samples.

CONCLUSIONS

Blood of male fetuses mounts a larger pro-inflammatory response to lipopolysaccharide (LPS). This heightened response could be a critical pathway in promoting premature rupture of membranes (PPROM) and may be associated with life long differential gender response to infection.

Biomarkers of spontaneous preterm birth: an overview of the literature in the last four decades

BACKGROUND

Understanding spontaneous preterm birth ([PTB] < 37 weeks) is difficult due to heterogeneities associated with multitudes of risk factors and pathophysiological pathways. Several biomarkers are routinely used clinically for predicting preterm labor; however, these factors are either nonspecific or detected too late.

OBJECTIVE

Systematic review of literature on PTB biomarkers in the last 40 years to map out the existing knowledge and gaps in understanding PTB biomarkers.

SEARCH STRATEGIES

Five electronic databases were searched for human studies on PTB biomarkers published in any language between 1965 and 2008.

SELECTION CRITERIA

The phenotype of interest for final data extraction was exclusively spontaneous PTB with no rupture of membranes. Data extraction included (a) general characteristics of the study (clinical setting, period, and study design), (b) study/participant characteristics (inclusion and exclusion criteria, race/ethnicity, number of participants, gestational age at sampling, (c) characteristics of the biomarker (type, rationale for its selection, type of biological sample, and assay used, and (d) concentration of biomarkers in cases and controls.

DATA COLLECTION AND ANALYSIS

The search yielded 7255 citations and data were extracted from 217 articles which met our inclusion and exclusion criteria.

MAIN RESULTS

A total of 116 different biomarkers were reported and these were assayed 578 times in the 217 included studies. Over two thirds of the 217 studies were performed on North American or European populations. No reliable biomarkers emerged as a risk predictor of PTB.

CONCLUSIONS

Identifying similar studies on biomarkers for the prediction of PTB was a very challenging task due heterogeneities in study design, sampling issues (types, timing and processing), assay methods, and analyses. Major areas of concern identified in this review include poor phenotype definition, nonideal study designs and poor rationale for biomarker selection and assays and population stratification issues.

A novel antiinflammatory role for the short-chain fatty acids in human labor

Human parturition is an inflammatory process that can be activated prematurely by pathological stimuli. This study investigated the expression of G protein-coupled receptors GPR43 and GPR41 receptors in human uteroplacental tissues and the role of short-chain fatty acids (SCFA) in modulating inflammatory pathways in fetal membranes. Expression of GPR43 and GPR41 was investigated in uteroplacental tissues collected from women delivering at term or preterm after ethical approval and patient informed consent. The effect of SCFA on expression of inflammatory genes was assessed in amnion explants after culture with a mimetic of infection (lipopolysaccharide, LPS). Sodium propionate effect on LPS-induced neutrophil chemotaxis was evaluated by transwell assay. GPR43 and GPR41 mRNA expression was higher in myometrium and fetal membranes collected from women after the onset of labor. GPR43 protein expression localized to immune cells and vascular endothelium in the myometrium and epithelium of fetal membranes. Treatment with LPS significantly increased mRNA expression of GPR43 and inflammatory genes. Cotreatment with LPS and sodium propionate decreased LPS-induced expression of inflammatory genes including IL-6, IL-8, cyclooxygenase-2, IL-1α, intercellular adhesion molecule-1, and platelet endothelial cell adhesion molecule-1 but not IL-1β or lymphocyte function-associated antigen-1. Sodium propionate reduced LPS-induced neutrophil chemotaxis and protein secretion of the neutrophil chemoattractant IL-8. Finally, fetal membrane expression of GPR43 was significantly higher in women delivering preterm with evidence of infection. GPR43-SCFA interactions may represent novel pathways that regulate inflammatory processes involved in human labor. Suppression of inflammatory pathways by SCFA may be therapeutically beneficial for pregnant women at risk of pathogen-induced preterm delivery.

An overview of racial disparities in preterm birth rates: caused by infection or inflammatory response?

Infection has been hypothesized to be one of the factors associated with spontaneous preterm birth (PTB) and with the racial disparity in rates of PTB between African American and Caucasian women. However, recent findings refute the generalizability of the role of infection and inflammation. African Americans have an increased incidence of PTB in the setting of intraamniotic infection, periodontal disease, and bacterial vaginosis compared to Caucasians. Herein we report variability in infection- and inflammation-related factors based on race/ethnicity. For African American women, an imbalance in the host proinflammatory response seems to contribute to infection-associated PTB, as evidenced by a greater presence of inflammatory mediators with limited or reduced presence of immune balancing factors. This may be attributed to differences in the genetic variants associated with PTB between African Americans and Caucasians. We argue that infection may not be a cause of racial disparity but in association with other risk factors such as stress, nutritional deficiency, and differences in genetic variations in PTB, pathways and their complex interactions may produce differential inflammatory responses that may contribute to racial disparity.

Sleep-disordered breathing and pregnancy: potential mechanisms and evidence for maternal and fetal morbidity

PURPOSE OF REVIEW

This article reviews current data on pathophysiologic mechanisms by which sleep-disordered breathing during pregnancy may cause harm, and explores biological pathways for associated adverse maternal and fetal outcomes, especially pregnancy-induced hypertension and gestational diabetes.

RECENT FINDINGS

Accumulating data indicate that snoring and sleep apnea during pregnancy are likely to increase the risk for gestational hypertension and preeclampsia. Several new studies have observed that sleep-disordered breathing and short sleep duration also increase the risk of gestational diabetes, similar to observations in the general population. There are varying levels of emerging evidence for potential mechanisms, including oxidative stress, increased sympathetic activity and inflammation, adipokine levels and insulin resistance, linking sleep-disordered breathing events during pregnancy to adverse outcomes.

SUMMARY

Sleep-disordered breathing and adverse maternal-fetal outcomes such as preeclampsia and gestational diabetes share a number of mechanistic pathways, and growing data in pregnant women indicate that snoring and sleep apnea increase the risk of these and other complications for both the mother and the fetus. Nevertheless, direct evidence of the pathophysiologic mechanisms by which sleep-disordered breathing during pregnancy exerts negative effects remains sparse.

Comparison of LPS-stimulated release of cytokines in punch versus transwell tissue culture systems of human gestational membranes

BACKGROUND

Cytokine signaling within the amnionic, chorionic and decidual extraplacental gestational membranes plays an important role in membrane rupture and the timing of birth. The predominant in vitro explant culture system for evaluating cytokine induction in human gestational membranes has been the free-floating biopsy punch culture. Punch systems have been used to investigate the impact of various toxicants, pharmaceuticals and genetic variation on expression of pro-inflammatory cytokines. More recently, a dual compartment transwell culture system has been developed that more closely mimics the intrauterine compartment. The current study compares these two systems with respect to release of pro- and anti-inflammatory cytokines in response to lipopolysaccharide (LPS), a model stimulant.

METHODS

Tissue samples were exposed to 100 ng/ml LPS for 12 h and cytokines were measured by ELISA. Data are expressed as increase relative to non-treated controls.

RESULTS

Levels of interleukin-6 increased in punch culture medium samples to a significantly greater extent (34.2 fold) compared with medium from transwell cultures in the amnion (6.6 fold) or choriodecidual (7.1 fold) compartments. Interleukin-8 also showed a significantly greater induction in punch (4.8 fold) than transwell amnion (1.6 fold) or choriodecidual (1.7 fold) samples. The anti-inflammatory interleukin-10 showed a significant difference between punch (36.5 fold) and transwell amnion (15.4 fold) samples, but no difference was observed between punch and transwell choriodecidual (28.5 fold) samples. Neither interleukin-1beta nor tumor necrosis factor-alpha (TNF-alpha) showed a significant difference between the punch and transwell samples.

CONCLUSIONS

These results indicate that the pattern of LPS-stimulated cytokine release from gestational membranes in vitro depends on the culture system used, confounding comparisons of studies that use different gestational membrane culture systems to study inflammatory responses.

A genetic association study of maternal and fetal candidate genes that predispose to preterm prelabor rupture of membranes (PROM)

OBJECTIVE

We sought to determine whether maternal/fetal single-nucleotide polymorphisms (SNPs) in candidate genes are associated with preterm prelabor rupture of membranes (pPROM).

STUDY DESIGN

A case-control study was conducted in patients with pPROM (225 mothers and 155 fetuses) and 599 mothers and 628 fetuses with a normal pregnancy; 190 candidate genes and 775 SNPs were studied. Single locus/haplotype association analyses were performed; false discovery rate was used to correct for multiple testing (q* = 0.15).

RESULTS

First, a SNP in tissue inhibitor of metalloproteinase 2 in mothers was significantly associated with pPROM (odds ratio, 2.12; 95% confidence interval, 1.47-3.07; P = .000068), and this association remained significant after correction for multiple comparisons. Second, haplotypes for Alpha 3 type IV collagen isoform precursor in the mother were associated with pPROM (global P = .003). Third, multilocus analysis identified a 3-locus model, which included maternal SNPs in collagen type I alpha 2, defensin alpha 5 gene, and endothelin 1.

CONCLUSION

DNA variants in a maternal gene involved in extracellular matrix metabolism doubled the risk of pPROM.

Identification of fetal and maternal single nucleotide polymorphisms in candidate genes that predispose to spontaneous preterm labor with intact membranes

OBJECTIVE

The purpose of this study was to determine whether maternal/fetal single nucleotide polymorphisms (SNPs) in candidate genes are associated with spontaneous preterm labor/delivery.

STUDY DESIGN

A genetic association study was conducted in 223 mothers and 179 fetuses (preterm labor with intact membranes who delivered <37 weeks of gestation [preterm birth (PTB)]), and 599 mothers and 628 fetuses (normal pregnancy); 190 candidate genes and 775 SNPs were studied. Single locus/haplotype association analyses were performed; the false discovery rate was used to correct for multiple testing.

RESULTS

The strongest single locus associations with PTB were interleukin-6 receptor 1 (fetus; P=.000148) and tissue inhibitor of metalloproteinase 2 (mother; P=.000197), which remained significant after correction for multiple comparisons. Global haplotype analysis indicated an association between a fetal DNA variant in insulin-like growth factor F2 and maternal alpha 3 type IV collagen isoform 1 (global, P=.004 and .007, respectively).

CONCLUSION

An SNP involved in controlling fetal inflammation (interleukin-6 receptor 1) and DNA variants in maternal genes encoding for proteins involved in extracellular matrix metabolism approximately doubled the risk of PTB.

Geographic ancestry and markers of preterm birth

Several biomarkers associated with spontaneous preterm birth (PTB) have been discovered over the last decade. Many of these markers, such as cytokines, are associated with infection and inflammation. As such, these biomarkers represent biologically plausible candidates for assessing those at risk of PTB. However, in the early association studies of biomarker-pregnancy outcome, the geographic ancestry of subjects was not considered. Based on more recent data, it is becoming increasingly evident that these biomarkers, and a universal approach that uses a single biomarker, fail to provide adequate assessment of risk in all subjects. Rather, recent data support the conclusion that some markers associate in subjects of African descent and another nonoverlapping set associates in subjects of European descent. These data indicate that diagnostic or predictive tests will have to use different biomarkers for different sets of subjects. If this is true, it poses severe restrictions on how to predict outcome or perform tests of association, and may make it impossible to determine risk or provide proper intervention. An alternative is presented that, although not yet proven, may make it possible to use a common set of biomarkers and their relationships to assess risk.

Integrated review of cytokines in maternal, cord, and newborn blood: part I--associations with preterm birth

Preterm birth (PTB; spontaneous delivery prior to 37 weeks gestation) affects one out of eight infants born in the United States and is the most common cause of neonatal morbidity and mortality. Although the pathogenesis of PTB is multifactorial, a growing body of literature supports the hypothesis that one cause of PTB is inflammation in pregnancy. Investigators have implicated mediators of inflammation, most notably proinflammatory cytokines, as being associated with and perhaps a playing a causal role in the pathogenesis of preterm labor and adverse early fetal outcomes. Though researchers have pursued the association of cytokines with preterm labor and subsequent early adverse fetal outcomes as a line of research, there has been little integration of diverse findings across studies. This systematic review appraises the empirical evidence from human studies for the association of levels of cytokines in blood with preterm labor and adverse early fetal outcome to examine the current state of the science in this important area of biobehavioral research. The most consistent finding is that increased levels of proinflammatory cytokines, particularly interleukin (IL) 6, IL-beta1, and tumor necrosis factor alpha (TNF-alpha), are associated with PTB as compared to levels found at term birth. However, there have been relatively few studies and results have not been consistent. Therefore, further research is needed to elucidate the association of these inflammatory mediators with adverse pregnancy outcomes.

TLR9 activation coupled to IL-10 deficiency induces adverse pregnancy outcomes

Pregnancy outcome is severely compromised by intrauterine infections and inflammation. Although the pregnant uterine microenvironment is replete with innate immune cells and TLR expression, the mechanisms that facilitate adverse effects of their activation are largely unknown. In this study, we mimic the activation of TLR9 with its pathogenic ligand hypomethylated CpG and demonstrate that IL-10 proficiency protects against CpG-induced pregnancy complications. We show that fetal resorption and preterm birth are rapidly induced in IL-10(-/-) mice by low doses of CpG (approximately 25 microg/mouse) when injected i.p. on gestational day 6 or gestational day 14, respectively. In contrast, wild-type mice failed to experience such effects at comparable doses, but pups born at term displayed craniofacial/limb defects in response to higher doses (approximately 400 microg/mouse). Pregnancy complications in IL-10(-/-) mice were associated with unexpected and robust TLR9-triggered activation and amplification of uterine neutrophil and macrophage subpopulations followed by their migration to the placental zone. Furthermore, a dramatic increase in serum levels of mouse KC and TNF-alpha production by uterine F4/80(+) cells, but not uterine NK or Gr-1(+)CD11b(+) cells, was observed. Depletion of F4/80(+) macrophages or neutralization of TNF-alpha rescued pregnancy to term. Our results have important implications for IL-10-mediated "uterine tolerance" against CpG-driven innate immune activation.

Racial disparity in pathophysiologic pathways of preterm birth based on genetic variants

OBJECTIVE

To study pathophysiologic pathways in spontaneous preterm birth and possibly the racial disparity associating with maternal and fetal genetic variations, using bioinformatics tools.

METHODS

A large scale candidate gene association study was performed on 1442 SNPs in 130 genes in a case (preterm birth < 36 weeks) control study (term birth > 37 weeks). Both maternal and fetal DNA from Caucasians (172 cases and 198 controls) and 279 African-Americans (82 cases and 197 controls) were used. A single locus association (genotypic) analysis followed by hierarchical clustering was performed, where clustering was based on p values for significant associations within each race. Using Ingenuity Pathway Analysis (IPA) software, known pathophysiologic pathways in both races were determined.

RESULTS

From all SNPs entered into the analysis, the IPA mapped genes to specific disease functions. Gene variants in Caucasians were implicated in disease functions shared with other known disorders; specifically, dermatopathy, inflammation, and hematological disorders. This may reflect abnormal cervical ripening and decidual hemorrhage. In African-Americans inflammatory pathways were the most prevalent. In Caucasians, maternal gene variants showed the most prominent role in disease functions, whereas in African Americans it was fetal variants. The IPA software was used to generate molecular interaction maps that differed between races and also between maternal and fetal genetic variants.

CONCLUSION

Differences at the genetic level revealed distinct disease functions and operational pathways in African Americans and Caucasians in spontaneous preterm birth. Differences in maternal and fetal contributions in pregnancy outcome are also different between African Americans and Caucasians. These results present a set of explicit testable hypotheses regarding genetic associations with preterm birth in African Americans and Caucasians.

How disturbed sleep may be a risk factor for adverse pregnancy outcomes

Adverse pregnancy outcomes associated with significant maternal and infant morbidity are on the rise in Western society despite advances of medical technology. Current risk factors are insufficient to identify women at greatest risk of developing an adverse outcome. An attempt to identify novel contributors to increased risk is warranted. Sleep disturbances are frequent during pregnancy, yet are often dismissed as irrelevant. Emerging evidence indicates that sleep disturbances are associated with poor health outcomes, including cardiovascular disease. Disturbed sleep is also linked with an increased inflammatory response. Increased inflammation is proposed as a key biological pathway through which chronic disease and adverse pregnancy outcomes develop. In this paper, we propose a model and a testable hypothesis of how disturbed sleep in the first 20 weeks of pregnancy could contribute to adverse pregnancy outcomes such as preeclampsia, intrauterine growth restriction, and preterm birth via increased inflammation.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Leaning Objectives: After completion of this article, the reader should be able to outline data linking sleep disturbances with an increased risk of some systemic disorders, recall characteristics of pregnancy complications which support the hypothesis that sleep disturbances may be related to these pregnancy outcomes, and summarize the likelihood and types of sleep disturbances that are common in pregnant women.

Cytokine SNPs: Comparison of allele frequencies by race and implications for future studies

The role of inflammation is being considered in chronic diseases. Previous studies have examined SNPs in a few key inflammatory genes and have included small numbers of African American participants. Variation in the frequencies of inflammatory pathway SNPs may help to explain racial disparities in disease risk. Through a population-based study of 103 African American and 380 Caucasian unrelated, healthy women, we examined the relationships between race and allele frequencies of 70 cytokine and cytokine receptor SNPs. The associations between genotypic and haplotype frequencies and race were also analyzed. Allelic frequencies for 52 out of the 70 SNPs meeting criteria for analysis differed significantly by race. Of the 32 pro-inflammatory and 20 anti-inflammatory SNPs for which the allele frequencies varied significantly by race, variant allele frequency differences between Caucasians and African Americans ranged between 6-37% and 7-53% for pro-inflammatory SNPs and anti-inflammatory SNPs, respectively. Our findings suggest that while allele frequencies do vary by race, racial groups are not simplistically represented by a pro-inflammatory or anti-inflammatory genetic profile. Given the racial variability in allele frequencies in inflammatory gene SNPs, studies examining the association between these SNPs and disease should at least incorporate self-reported race in their analyses.

Corticotrophin-releasing hormone in lipopolysaccharide-stimulated term fetal membranes and amniotic fluid from term and preterm birth in African Americans and Caucasians

The objective of this study is to document differences in corticotrophin-releasing hormone (CRH), CRH receptor 1 (CRHR1), and CRH binding protein (CRHBP) gene expression in fetal membranes derived from African Americans and Caucasians in vitro in response to lipopolysaccharide (LPS) stimulation and to assess racial disparity in CRH concentrations in the amniotic fluid (AF) of women with spontaneous preterm birth (PTB). Fetal membranes (African American, n = 8; Caucasian, n = 8) at term, placed in an organ explant system, were stimulated with LPS. Microarray analysis documented differences in the mRNA expression pattern of CRH, CRHBP, and CRHR1 between races. CRH was measured in AF (a case [PTB]-control [term] study) and culture media. Between races, LPS significantly increased CRH and CRHR1 expression in African Americans and CRHBP in Caucasians, with no differences in controls. CRH was detectable only in LPS-stimulated African American membranes. AF CRH concentrations were higher in PTB compared with controls (P < .001), and no difference was noticed between races (P = .1). AF analysis did not document racial disparity in CRH concentrations in PTB. In fetal membranes, African Americans showed a higher expression and production of CRH in response to an in vitro stimulus.

Region-specific gene expression profiling: novel evidence for biological heterogeneity of the human amnion

The amnion plays an important role during pregnancy and parturition. Though referred to as a single structure, this fetal tissue is regionally divided into placental amnion, reflected amnion, and umbilical amnion. Histological differences between placental amnion and reflected amnion led us to hypothesize that the amnion is biologically heterogeneous. The gene expression profiles of placental amnion and reflected amnion were compared in patients at term with no labor (TNL; n = 10) and in labor (TIL; n = 10). Real-time quantitative RT-PCR revealed a higher expression of IL1B mRNA in reflected amnion than in placental amnion in TNL cases but not in TIL cases. Extended screening using microarrays showed differential expression of 17 genes in labor, regardless of the region. Interestingly, 839 genes were differentially expressed between placental amnion and reflected amnion. Pathway analysis identified 19 signaling pathways, such as mitogen-activated protein kinase and transforming growth factor beta pathways, associated with region. Lipopolysaccharide (LPS) treatment of the amnion explants showed more robust activation of mitogen-activated protein kinase 3/1 (extracellular signal-regulated kinase 1/2) in placental amnion of TNL but not in TIL cases. Placental amnion from TNL and TIL cases showed a significant difference in the amplitude of IL1B mRNA induction by LPS. We report that the anatomical region has a substantial impact on the transcriptional program and the biological properties of the amnion. Labor-associated switching to a proinflammatory signature is a feature particular to placental amnion. The novel observations herein strongly suggest that the seemingly homogeneous amnion is biologically heterogeneous and compartmentalized, with implications for the physiology of pregnancy and parturition.

Patterns of cytokine profiles differ with pregnancy outcome and ethnicity

BACKGROUND

Preterm birth (PTB) is hypothesized to be an inflammatory response disease. However, no single factor alone is likely to explain PTB risk. It is more probable that coordinated networks of cytokines affect risk.

METHODS

Therefore, we examined the relationships between amniotic fluid (AF) cytokines/chemokines and related biomarkers in PTB and normal term deliveries in African Americans and Caucasians. Data were obtained from African American (41 preterm labor and 91 term labor) and Caucasian (105 preterm labor and 100 term labor) pregnant mothers. Pro-inflammatory cytokines and related molecules interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor- (TNF)-alpha, TNF soluble receptors (sTNFR1 and sTNFR2), and anti-inflammatory cytokine IL-10 that were all previously associated with PTB were studied. Correlations between biomarkers were calculated; differences of correlation coefficients between AF from African American and Caucasian samples in preterm labor and term labor were measured.

RESULTS

Multiple differences were observed between African American and Caucasian preterm and term birth groups. In term birth the strongest differences were between pro- and anti-inflammatory correlations, whereas in PTB differences were equally distributed between pro-inflammatory/anti-inflammatory and pro-inflammatory/pro-inflammatory correlations. Three correlation patterns differed significantly between AF from PTB African Americans with and without microbial invasion of the intra-amniotic cavity (MIAC); no differences were observed in Caucasians with MIAC.

CONCLUSION

Correlation analyses of cytokine measurements suggest coordinated interplay during pregnancy; significant differences exist between African Americans and Caucasians. Such analyses can serve as a means of understanding risk factors in these populations.

Association of preterm birth with sustained postnatal inflammatory response

OBJECTIVE

To investigate fetal or neonatal inflammatory patterns based on 25 inflammatory markers in neonatal dried blood spots samples from infants born preterm and term, collected several days after birth.

METHODS

Dried blood spots samples from 160 neonates were analyzed for 25 inflammatory markers using multiplex technology: 26 neonates born very preterm (before 32 weeks of gestation), drawn at a mean 6 days (95% confidence interval [CI], 5-7 days) after birth; 52 born preterm (32-36 weeks of gestation), drawn at mean 5 days (95% CI, 5-6 days) after birth; and 82 born at term (at or after 37 weeks of gestation), drawn at mean 5 days (95% CI, 5-5 days) after birth. Markers statistically significantly associated with preterm birth were analyzed in a multivariable model together with maternal and neonatal risk factors for preterm birth.

RESULTS

Elevated levels of interleukin (IL)-1beta, IL-6, soluble IL-6ralpha, IL-8, matrix metalloproteinase-9, and transforming growth factor-beta1 and decreased levels of IL-18, brain-derived neurotrophic factor, and C-reactive protein were associated with preterm birth. Maternal risk factors could explain only an increase of IL-1beta, whereas neonatal factors could explain several of the elevated and decreased inflammatory markers in the dried blood spots samples from the infants born preterm compared with the infants born at term.

CONCLUSION

The differences in levels of inflammatory markers in dried blood spots samples from infants born preterm compared with infants born at term supports the hypothesis that inflammation of fetal origin might be a cause of preterm birth.

LEVEL OF EVIDENCE

II.

Racial disparity in maternal-fetal genetic epistasis in spontaneous preterm birth

OBJECTIVE

To understand the differences in genetic interactions among tumor necrosis factor-alpha, interleukin-6 and their receptor gene variants between black and white patients in spontaneous preterm birth.

STUDY DESIGN

Maternal and fetal DNA (n = 1195) were collected from cases (preterm birth < 36 weeks' gestation; n = 448), controls (> 37 weeks' gestation; n = 747), and genotyped for single nucleotide polymorphisms in tumor necrosis factor-alpha, tumor necrosis factor receptor 1, and tumor necrosis factor receptor 2, interleukin-6, and interleukin-6 receptor loci. Multifactor dimensionality reduction analysis was used to test all single and multilocus combinations for the ability to predict pregnancy outcome.

RESULTS

In white patients, multilocus interactions in maternal DNA between single nucleotide polymorphisms at -7227 (interleukin-6), 22,215 (interleuki-6 receptor) and -3448 (tumor necrosis factor-alpha) was predictive of approximately 59.1% (P < .02; odds ratio, 2.3 [95% confidence interval = 1.6-3.4]) of pregnancy outcome. In white fetal DNA and black maternal DNA, no significant interactive models were observed. In black patients, the best epistatic model was in fetal DNA between single nucleotide polymorphisms at 17,691 (tumor necrosis factor-receptor 1) and at -3448 (tumor necrosis factor-alpha) and was predictive of pregnancy outcome 68.3% of the time (P < .01; odds ratio, 5.0 [95% confidence interval = 2.6-9.6]).

CONCLUSION

Analyses of multilocus interactions found/associated different models in black and white patients in both maternal and fetal DNA with preterm birth as outcome. Significant maternal-fetal interactions were not detected in either race.

Racial disparity in amniotic fluid concentrations of tumor necrosis factor (TNF)-alpha and soluble TNF receptors in spontaneous preterm birth

OBJECTIVE

Preterm birth rate in the United States is higher in blacks than whites. It has been hypothesized that a differential inflammatory response may explain this disparity. The objective of this study is to examine the inflammatory cytokine, tumor necrosis factor (TNF)-alpha and soluble TNF receptor concentrations (sTNFR1 and sTNFR2) in the amniotic fluid of black and white women at delivery.

STUDY DESIGN

Amniotic fluid samples were collected during active labor from 158 cases (preterm births, gestational age 22(0/7) weeks to 36(0/7) weeks, 52 black and 106 white) and 175 controls (term births, gestational age 37(0/7) weeks to 42(0/7) weeks, 87 black and 88 white) at Centennial Women's Hospital, Nashville, TN. Amniotic fluid TNF-alpha, sTNFR1, and sTNFR2 concentrations and the molar ratios of TNF-alpha to its receptors were compared between cases and controls within each racial group.

RESULTS

Median TNF-alpha concentration was associated with preterm birth when whites and blacks were analyzed together, with cases having higher values (191.5 pg/mL) than controls (68.9 pg/mL; P < .001). There were no significant associations with sTNFR1 or sTNFR2 concentrations between cases (2409.4 and 2934.3 pg/mL, respectively) and controls (2759.9 and 3084.1 pg/mL, respectively) when the racial groups were analyzed together (P = .08, P = .4, respectively). Black cases associated with higher TNF-alpha concentrations (1287.0 pg/mL in cases and 67.3 pg/mL in controls; P < .001). In whites there was no association between TNF-alpha and preterm birth (P = .3). The molar ratio of TNF-alpha/total sTNFR (R1 plus R2) associated with higher TNF-alpha in black cases, compared with black controls (P < .001). There was no significant association between white cases and controls for ligand receptor ratios (P = .3).

CONCLUSION

The TNF-alpha/sTNFR profile in pregnancy differs between racial groups, suggesting a difference in bioavailability of TNF-alpha. The larger molar ratio of TNF-alpha/sTNFR in black cases may be indicative of a TNF-alpha mediated pathological process of preterm birth in blacks but not in whites.

Amniotic fluid interleukin-6 increase is an indicator of spontaneous preterm birth in white but not black Americans

OBJECTIVE

This study examined the differences in the inflammatory cytokine interleukin (IL)-6 and the immunoinhibitory cytokine IL-10 in the amniotic fluid of black and white women in spontaneous preterm birth.

METHODS

In this study, 321 amniotic fluids from cases (preterm birth 36 or fewer weeks' gestation) and controls (normal term delivery longer than 37 weeks' gestation) were collected (147 cases [49 blacks and 98 whites] and 174 controls [85 blacks and 89 whites]) at the time of active labor. IL-6 and IL-10 concentrations were measured by immunoassays. Using normal-term delivery as controls, logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CIs) for preterm birth.

RESULTS

A significant difference in IL-6 concentration was observed in white cases (cases: 3773 pg/mL; controls: 1682 pg/mL; P = .0003), compared with controls, but not in blacks (cases: 2042 pg/mL; controls: 2366 pg/mL; P = .6). In a combined multivariable analysis, when the highest and the lowest quartiles of IL-6 were compared in whites, the ORs (95% CI) for preterm birth across quartiles were 1.74 (0.62-4.88), 1.09 (0.39-3.02), and 5.68 (2.15-15.0). No such association was found in blacks. IL-10 concentration was not different between cases and controls in either race.

CONCLUSIONS

Race-specific associations exist between IL-6 but not IL-10 concentration and preterm birth. Elevated IL-6 concentrations are associated with preterm birth in whites but not blacks.

Exodus-1 (CCL20): evidence for the participation of this chemokine in spontaneous labor at term, preterm labor, and intrauterine infection

AIM

CCL20, also known as MIP-3 alpha, is a chemokine that participates in chemotaxis of immature dendritic cells, effector/memory T-cells, and B-lymphocytes. The objectives of this study were to determine whether CCL20 can be detected in amniotic fluid (AF) and if AF concentration of this chemokine changes with advancing gestational age, parturition (term and preterm), and intra-amniotic infection/inflammation (IAI).

METHODS

A cross-sectional study was conducted including the following groups: (1) mid-trimester of pregnancy (n=65); (2) term not in labor (TNL; n=22); (3) term in labor (TIL; n=47); (4) spontaneous preterm labor (PTL) who delivered at term (n=57); (5) spontaneous PTL without IAI who delivered preterm (n=71); and (6) spontaneous PTL with IAI (n=38). AF CCL20 concentrations were determined using ELISA.

RESULTS

(1) The median AF CCL20 concentration in TNL was higher than that of mid-trimester patients; (2) Women in spontaneous labor at term had a higher median AF concentration of CCL20 than patients at term not in labor; (3) Patients with spontaneous PTL and IAI had a significantly higher median AF concentration of CCL20 than those without IAI who delivered preterm and those who delivered at term. Moreover, women with spontaneous PTL without IAI who delivered preterm had a significantly higher median AF concentration than those with PTL who subsequently delivered at term.

CONCLUSIONS

(1) CCL20 is a physiologic constituent of AF and its concentration increases as term approaches; (2) spontaneous labor (term and preterm) in the absence of IAI is associated with increased bioavailability of AF CCL20 suggesting that an increase in CCL20 is part of the common pathway of human parturition; (3) patients with IAI had dramatic elevations in the AF CCL20 concentrations suggesting that this chemokine participates in the host response to infection or other stimuli associated with intra-amniotic infection.

Amniotic fluid interleukin-1beta and interleukin-8 concentrations: racial disparity in preterm birth

The purpose of this study is to examine the racial differences between interleukin (IL)-1beta and IL-8 concentrations in the amniotic fluid of black and white women with spontaneous preterm birth (PTB). In this study, 350 amniotic fluid samples were collected: 165 PTB cases (<36 weeks' gestation; 52 blacks and 113 whites) and 185 controls (normal term delivery >37 weeks' gestation; 87 blacks and 98 whites). Amniotic fluid IL-1beta and IL-8 concentrations were measured by immunoassay. Wilcoxon nonparametric test was performed for statistical analysis. In data stratified by race, the median IL-1beta concentration was significantly higher in black cases (80 pg/mL) compared to black controls (23.7 pg/mL; P < .0001), and the difference was nonsignificant in white cases (25.5 pg/mL) compared to white controls (21.3 pg/mL; P = .1). IL-8 concentration was not higher in black cases (742.2 pg/mL) compared to black controls (731.4 pg/mL; P = .9), whereas it was higher in white cases (1362.3 pg/mL) compared to white controls (533.5 pg/mL; P = .0005). Between races, IL-1beta was significantly higher in blacks (P < .0001) than in whites in PTB, whereas no significant difference was noticed in IL-8 concentration between races (P = .1). In PTB, the cytokine footprint differs in the amniotic fluid between racial groups. IL-1beta is higher in black and IL-8 in white PTB. These differences in the amniotic fluid cytokine concentration might not explain the racial disparity in the PTB rate, but they are suggestive of different processes of PTB in whites and blacks.

Association of interleukin-1beta and interleukin-1 receptor antagonist polymorphisms with bacterial vaginosis in non-pregnant Italian women

Bacterial vaginosis (BV) is the most prevalent alteration of vaginal microflora worldwide. BV is a polymicrobial disorder, and its etiology is elusive. Factors predisposing to this recurrent condition are not fully characterized. We aimed to investigate whether interleukin-1beta (IL-1beta) and IL-1 receptor antagonist (IL-1ra) polymorphisms are associated with BV in non-pregnant white Italian women. Genomic DNA was obtained from 164 BV positive, and 406 control women. Two diallelic polymorphisms in the IL-1beta gene (IL-1B) representing C/T base transitions at - 511 and + 3954 positions and a variable number tandem repeats (VNTR) in intron 2 of the IL-1ra gene (IL-1RN) were assessed. We demonstrated that women who were homozygous for - 511 CC or + 3954 TT of the IL-1B gene were at increased risk for BV with an odds ratio (OR) = 1.5 [95% confidence interval (CI) = 1.03-2.14, P = 0.032], and OR = 2.8 (95% CI = 1.37-5.88, P = 0.004), respectively. The haplotype - 511/ + 3954 T-C was protective for BV, with an OR = 0.7 (95% CI = 0.49-0.90, P = 0.009). The IL-1RN VNTR genotype was not associated with BV, although the rare allele 3 showed a trend towards protection (P = 0.049). These data show that host genetic variants at the IL-1beta locus predispose to BV among Caucasian non-pregnant women. Further studies will determine whether these genetic polymorphisms modulate the risk for BV recurrence, and/or BV associated severe adverse outcomes as preterm birth and human immunodeficiency virus transmission.

Analysis of association between maternal tumor necrosis factor-alpha promoter polymorphism (-308), tumor necrosis factor concentration, and preterm birth

OBJECTIVE

This study was undertaken to investigate the association of tumor necrosis factor-alpha (TNF-alpha) single nucleotide polymorphism (G-308>A) and risk of preterm birth by performing a systematic review and a meta-analysis of available studies. In addition, association between this variant and TNF-alpha concentration in amniotic fluid (AF) in preterm birth was also investigated.

STUDY DESIGN

Articles were chosen based on a Medline and EMBASE searches (1990-2005) with no language restrictions. An ongoing case-control study conducted in Nashville, TN, was also included. Articles evaluating the association between G-308>A and preterm birth were screened according to specific inclusion criteria. Meta-analysis was performed by using a random effect model. Association between maternal -308 genotype and AF-TNF-alpha concentration was determined by sandwich immunoassays.

RESULTS

Titles and abstracts of 6851 citations identified through the search were screened. Including our own study, a total of 7 studies were included for meta-analysis. Only 2 reported a statistically significant increased risk based on -308 genotype. Meta-analysis of the case-control studies on a pooled dataset (a total of 1846 subjects, 638 cases, and 1208 controls) showed no significant association between the -308 genotype and the risk of preterm birth (odds ratio [OR] 1.41; CI 0.90-2.19). A nonsignificant increase of AF TNF-alpha concentration was demonstrated with the GG genotype in cases compared with the presence of allele A.

CONCLUSION

Meta-analysis of available evidence documented no statistically significant association between a single nucleotide polymorphism in the TNF-alpha gene (G-308>A) and preterm birth. Analyses of AF-TNF-alpha concentration demonstrated no increase in TNF-alpha in the presence of the minor allele (A). These results suggest that this single nucleotide polymorphism does not independently associate strongly with preterm birth.