The role of inflammation and infection in preterm birth

The hormonal control of parturition

Parturition is a complex physiological process that must occur in a reliable manner and at an appropriate gestation stage to ensure a healthy newborn and mother. To this end, hormones that affect the function of the gravid uterus, especially progesterone (P4), 17β-estradiol (E2), oxytocin (OT), and prostaglandins (PGs), play pivotal roles. P4 via the nuclear P4 receptor (PR) promotes uterine quiescence and for most of pregnancy exerts a dominant block to labor. Loss of the P4 block to parturition in association with a gain in prolabor actions of E2 are key transitions in the hormonal cascade leading to parturition. P4 withdrawal can occur through various mechanisms depending on species and physiological context. Parturition in most species involves inflammation within the uterine tissues and especially at the maternal-fetal interface. Local PGs and other inflammatory mediators may initiate parturition by inducing P4 withdrawal. Withdrawal of the P4 block is coordinated with increased E2 actions to enhance uterotonic signals mediated by OT and PGs to promote uterine contractions, cervix softening, and membrane rupture, i.e., labor. This review examines recent advances in research to understand the hormonal control of parturition, with focus on the roles of P4, E2, PGs, OT, inflammatory cytokines, and placental peptide hormones together with evolutionary biology of and implications for clinical management of human parturition.

Pregnancy outcomes in patients with familial Mediterranean fever: systematic review and meta-analysis

OBJECTIVE

The relationship between FMF and pregnancy outcomes remains unclear. This systematic review and meta-analysis aimed to clarify this association.

METHODS

Electronic databases-PubMed, Web of Science, Cochrane, and EMBASE-were searched on 20 December 2022, using specific search terms. Case-control, cohort, and randomized clinical trial studies comparing patients with FMF and healthy controls were considered eligible. We excluded systematic reviews, meta-analyses, case series with fewer than five cases, republished articles without new findings on pregnancy outcomes, studies targeting paternal FMF, and those not published in English. The results were summarized in the form of odds ratios (ORs) and 95% CIs, using a random-effects model. This study was registered in the University hospital Medical Information Network Clinical Trials Registry (Japan) as UMIN000049827.

RESULTS

The initial electronic search identified 611 records, of which 9 were included in this meta-analysis (177 735 pregnancies, 1242 with FMF, and 176 493 healthy controls). FMF was significantly associated with increased odds of preterm deliveries (OR, 1.67; 95% CI, 1.05-2.67; I2 = 22%) and insignificantly associated with increased odds of fetal growth restriction (OR, 1.45; 95% CI, 0.90-2.34; I2 = 0%) and hypertensive disorders during pregnancy (OR, 1.28; 95% CI, 0.87-1.87; I2 = 0%).

CONCLUSION

FMF was significantly associated with preterm delivery and insignificantly associated with fetal growth restriction and hypertensive disorders. All of the included studies were observational studies. Treatment characteristics were not fully collected from the articles, and further analysis of treatments for FMF in pregnancy is still warranted.

Antibody Response to the Sneathia vaginalis Cytopathogenic Toxin A during Pregnancy

Sneathia vaginalis is a Gram-negative vaginal species that is associated with pregnancy complications. It produces cytopathogenic toxin A (CptA), a pore-forming toxin. To determine whether CptA is expressed in vivo and to examine the mucosal Ab response to the toxin, we examined human midvaginal swab samples obtained during pregnancy for IgM, IgA, and IgG Abs with CptA affinity. This subcohort study included samples from 93 pregnant people. S. vaginalis relative abundance was available through 16S rRNA survey. There were 22 samples from pregnancies that resulted in preterm birth in which S. vaginalis relative abundance was <0.005%, 22 samples from pregnancies that resulted in preterm birth with S. vaginalis ≥0.005%, 24 samples from pregnancies that resulted in term birth with S. vaginalis <0.005%, and 25 samples from pregnancies that resulted in term birth with S. vaginalis ≥0.005%. IgM, IgA, and IgG with affinity for CptA were assessed by ELISA. The capacity for the samples to neutralize CptA was quantified by hemolysis assay. All three Ab isotypes were detectable within different subsets of the samples. There was no significant association between relative abundance of S. vaginalis and the presence of any Ab isotype. The majority of vaginal swab samples containing detectable levels of anti-CptA Abs neutralized the hemolytic activity of CptA, with the strongest correlation between IgA and neutralizing activity. These results demonstrate that S. vaginalis produces CptA in vivo and that CptA is recognized by the host immune defenses, resulting in the production of Abs with toxin-neutralizing ability.

Host-microbiome interactions in distinct subsets of preterm labor and birth

Preterm birth, the leading cause of perinatal morbidity, often follows premature labor, a syndrome whose prevention remains a challenge. To better understand the relationship between premature labor and host-microbiome interactions, we conducted a mechanistic investigation using three preterm birth models. We report that intra-amniotic delivery of LPS triggers inflammatory responses in the amniotic cavity and cervico-vaginal microenvironment, causing vaginal microbiome changes and signs of active labor. Intra-amniotic IL-1α delivery causes a moderate inflammatory response in the amniotic cavity but increasing inflammation in the cervico-vaginal space, leading to vaginal microbiome disruption and signs of active labor. Conversely, progesterone action blockade by RU-486 triggers local immune responses accompanying signs of active labor without altering the vaginal microbiome. Preterm labor facilitates ascension of cervico-vaginal bacteria into the amniotic cavity, regardless of stimulus. This study provides compelling mechanistic insights into the dynamic host-microbiome interactions within the cervico-vaginal microenvironment that accompany premature labor and birth.

Evidence for the participation of CHCHD2/MNRR1, a mitochondrial protein, in spontaneous labor at term and in preterm labor with intra-amniotic infection

OBJECTIVE

Intra-amniotic inflammation (IAI), associated with either microbe (infection) or danger signals (sterile), plays a major role in the pathophysiology of preterm labor and delivery. Coiled-Coil-Helix-Coiled-Coil-Helix Domain Containing 2 (CHCHD2) [also known as Mitochondrial Nuclear Retrograde Regulator 1 (MNRR1)], a mitochondrial protein involved in oxidative phosphorylation and cell survival, is capable of sensing tissue hypoxia and inflammatory signaling. The ability to maintain an appropriate energy balance at the cellular level while adapting to environmental stress is essential for the survival of an organism. Mitochondrial dysfunction has been observed in acute systemic inflammatory conditions, such as sepsis, and is proposed to be involved in sepsis-induced multi-organ failure. The purpose of this study was to determine the amniotic fluid concentrations of CHCHD2/MNRR1 in pregnant women, women at term in labor, and those in preterm labor (PTL) with and without IAI.

METHODS

This cross-sectional study comprised patients allocated to the following groups: (1) mid-trimester (n = 16); (2) term in labor (n = 37); (3) term not in labor (n = 22); (4) PTL without IAI who delivered at term (n = 25); (5) PTL without IAI who delivered preterm (n = 47); and (6) PTL with IAI who delivered preterm (n = 53). Diagnosis of IAI (amniotic fluid interleukin-6 concentration ≥2.6 ng/mL) included cases associated with microbial invasion of the amniotic cavity and those of sterile nature (absence of detectable bacteria, using culture and molecular microbiology techniques). Amniotic fluid and maternal plasma CHCHD2/MNRR1 concentrations were determined with a validated and sensitive immunoassay.

RESULTS

(1) CHCHD2/MNRR1 was detectable in all amniotic fluid samples and women at term without labor had a higher amniotic fluid CHCHD2/MNRR1 concentration than those in the mid-trimester (p = 0.003); (2) the amniotic fluid concentration of CHCHD2/MNRR1 in women at term in labor was higher than that in women at term without labor (p = 0.01); (3) women with PTL and IAI had a higher amniotic fluid CHCHD2/MNRR1 concentration than those without IAI, either with preterm (p < 0.001) or term delivery (p = 0.01); (4) women with microbial-associated IAI had a higher amniotic fluid CHCHD2/MNRR1 concentration than those with sterile IAI (p < 0.001); (5) among women with PTL and IAI, the amniotic fluid concentration of CHCHD2/MNRR1 correlated with that of interleukin-6 (Spearman's Rho = 0.7; p < 0.001); and (6) no correlation was observed between amniotic fluid and maternal plasma CHCHD2/MNRR1 concentrations among women with PTL.

CONCLUSION

CHCHD2/MNRR1 is a physiological constituent of human amniotic fluid in normal pregnancy, and the amniotic concentration of this mitochondrial protein increases during pregnancy, labor at term, and preterm labor with intra-amniotic infection. Hence, CHCHD2/MNRR1 may be released into the amniotic cavity by dysfunctional mitochondria during microbial-associated IAI.

Interferon-stimulated gene 15 polymorphisms are associated with spontaneous preterm birth in Taiwanese women

PROBLEM

Immune and inflammatory responses are known to be major causes of preterm birth (PTB). The maternal genetic background plays an important role in the development of PTB. Interferon-stimulated gene 15 (ISG15) is an interferon-induced protein which can modulate immune cell activation and function. We aim to study if polymorphisms in the ISG15 gene are associated with spontaneous PTB (sPTB) risk in Taiwanese women.

METHOD OF STUDY

ISG15 rs4615788 C/G, rs1921 G/A, and rs8997 A/G polymorphisms were genotyped in a hospital-based study of 112 women with sPTB and 1120 term controls. The plasma concentrations of ISG15 were determined by enzyme-linked immunosorbent assay.

RESULTS

We found the ISG15 rs1921 G-rs8997 A haplotype was associated with decreased risk for PTB (χ2  = 6.26, p = .01, pc  = .04). The A/G genotype of ISG15 rs8997 polymorphism might have the potential to confer reduced risk of PTB women (χ2  = 4.09, p = .04, pc  = .08). Spontaneous PTB women displayed higher plasma ISG15 levels compared to term controls (p < .001). The plasma ISG15 levels among pregnant women with rs8997 A/G genotype were found significantly lower compared to G/G genotype (p = .03).

CONCLUSIONS

Women with the ISG15 rs1921 G-rs8997 A haplotype may associate with spontaneous PTB. These findings provide new insights into the etiology of preterm birth.

A key role for NLRP3 signaling in preterm labor and birth driven by the alarmin S100B

Preterm birth remains the leading cause of neonatal morbidity and mortality worldwide. A substantial number of spontaneous preterm births occur in the context of sterile intra-amniotic inflammation, a condition that has been mechanistically proven to be triggered by alarmins. However, sterile intra-amniotic inflammation still lacks treatment. The NLRP3 inflammasome has been implicated in sterile intra-amniotic inflammation; yet, its underlying mechanisms, as well as the maternal and fetal contributions to this signaling pathway, are unclear. Herein, by utilizing a translational and clinically relevant model of alarmin-induced preterm labor and birth in Nlrp3-/- mice, we investigated the role of NLRP3 signaling by using imaging and molecular biology approaches. Nlrp3 deficiency abrogated preterm birth and the resulting neonatal mortality induced by the alarmin S100B by impeding the premature activation of the common pathway of labor as well as by dampening intra-amniotic and fetal inflammation. Moreover, Nlrp3 deficiency altered leukocyte infiltration and functionality in the uterus and decidua. Last, embryo transfer revealed that maternal and fetal Nlrp3 signaling contribute to alarmin-induced preterm birth and neonatal mortality, further strengthening the concept that both individuals participate in the complex process of preterm parturition. These findings provide novel insights into sterile intra-amniotic inflammation, a common etiology of preterm labor and birth, suggesting that the adverse perinatal outcomes resulting from prematurity can be prevented by targeting NLRP3 signaling.

Integration of transcriptomics and metabolomics reveals the responses of the maternal circulation and maternal-fetal interface to LPS-induced preterm birth in mice

Background

Term birth (TB) and preterm birth (PTB) are characterized by uterine contractions, rupture of the chorioamniotic membrane, decidual activation, and other physiological and pathological changes. In this study, we hypothesize that inflammation can cause changes in mRNA expression and metabolic stability in the placenta, decidua, chorioamniotic membrane, uterus and peripheral blood, ultimately leading to PTB.

Methods

To comprehensively assess the effects of inflammation on mRNA expression and metabolite production in different tissues of pregnancy, we used a mouse PTB model by intraperitoneally injecting lipopolysaccharide (LPS) and integrated transcriptomics and metabolomics studies.

Results

Our analysis identified 152 common differentially expressed genes (DEGs) and 8 common differentially expressed metabolites (DEMs) in the placenta, decidua, chorioamniotic membrane, uterus, and peripheral blood, or placenta and uterus after LPS injection, respectively. Our bioinformatics analysis revealed significant enrichment of the NOD-like receptor signaling pathway (mmu04621), TNF signaling pathway (mmu04668), IL-17 signaling pathway (mmu04657), and NF-kappa B signaling pathway in the transcriptomics of different tissues, and Hormone synthesis, Lysosome, NOD-like receptor signaling pathway, and Protein digest and absorption pathway in metabolomics. Moreover, we found that several upstream regulators and master regulators, including STAT1, STAT3, and NFKB1, were altered after exposure to inflammation in the different tissues. Interaction network analysis of transcriptomics and metabolomics DEGs and DEMs also revealed functional changes in mice intraperitoneally injected with LPS.

Conclusions

Overall, our study identified significant and biologically relevant alterations in the placenta, decidua, chorioamniotic membrane, uterus, peripheral blood transcriptome and the placenta and uterus metabolome in mice exposed to LPS. Thus, a comprehensive analysis of different pregnancy tissues in mice intraperitoneally injected with LPS by combining transcriptomics and metabolomics may help to systematically understand the local and systemic changes associated with PTB caused by inflammation.

Use of personal care products during pregnancy and birth outcomes - A pilot study

Prenatal exposure to endocrine disrupting chemicals (EDCs) from personal care products may be associated with birth outcomes including preterm birth and low birth weight. There is limited research examining the role of personal care product use during pregnancy on birth outcomes. Our pilot study consisted of 164 participants in the Environmental Reproductive and Glucose Outcomes (ERGO) study (Boston, MA), with data on self-reported personal care product use at four study visits throughout pregnancy (product use in the 48 h before a study visit and hair product use in the month before a study visit). We used covariate-adjusted linear regression models to estimate differences in mean gestational age at delivery, birth length, and sex-specific birth weight-for-gestational age (BW-for-GA) Z-score based on personal care product use. Hair product use in the past month prior to certain study visits was associated with decreased mean sex-specific BW-for-GA Z-scores. Notably, hair oil use in the month prior to study visit 1 was associated with a lower mean BW-for-GA Z-score (V1: -0.71, 95% confidence interval: -1.12, -0.29) compared to non-use. Across all study visits (V1-V4), increased mean birth length was observed among nail polish users vs. non-users. In comparison, decreased mean birth length was observed among shave cream users vs. non-users. Liquid soap, shampoo, and conditioner use at certain study visits were significantly associated with higher mean birth length. Suggestive associations were observed across study visits for other products including hair gel/spray with BW-for-GA Z-score and liquid/bar soap with gestational age. Overall, use of a variety of personal care products throughout pregnancy was observed to be associated with our birth outcomes of interest, notably hair oil use during early pregnancy. These findings may help inform future interventions/clinical recommendations to reduce exposures linked to adverse pregnancy outcomes.

Markers of intestinal immune activation and inflammation are not associated with preterm birth among women with low level HIV viremia

BACKGROUND

Maternal markers of intestinal immune activation may be used to predict preterm birth (PTB) in pregnant women living with HIV.

METHODS

This study used de-identified samples from the International Maternal Pediatric Adolescent AIDS Clinical Trials Group (IMPAACT) Protocol P1025 study. Singleton pregnancies with ≥3 ml plasma available and HIV viral load ≤400 copies/ml within 4 weeks of specimen collection were included. Frequency matching of PTB cases and term birth controls was performed on basis of maternal race, number of available plasma specimens, and timing of plasma sample collection in a 1:1 ratio. Plasma progesterone, 25-hydroxy vitamin D, soluble CD14, intestinal fatty acid binding protein (I-FABP), Lipopolysaccharide (LPS)-binding protein, and inflammatory cytokines (IL-1B, IFN-gamma, IL-6, TNF-alpha) were measured. Generalized mixed linear regression modeling was used to examine the association between PTB and biomarkers, adjusting for covariates and confounders. Data analyses were performed using SAS 9.4 (Cary, NC).

RESULTS

We included 104 PTB compared to 104 controls. Third trimester log2 IL-1B was lower among PTB versus term birth controls by univariate analysis (-1.50 ± 2.26 vs. -.24 ± 2.69, p = .01) though this association was no longer significant by regression modeling. In an uncontrolled, exploratory sub-analysis, subjects with prior PTB had increased odds of PTB with higher I-FABP [aOR 2.72, 95% CI 1.18-6.24] and lower IFN-gamma [aOR .23, 95% CI .12-.41] after adjustment for covariates and confounders.

CONCLUSIONS

Intestinal immune activation measured by soluble CD14 or intestinal fatty acid binding protein was not associated with preterm birth among pregnant women with low-level HIV viremia.

A single-cell atlas of murine reproductive tissues during preterm labor

Preterm birth, the leading cause of perinatal morbidity and mortality worldwide, frequently results from the syndrome of preterm labor. The best-established causal link to preterm labor is intra-amniotic infection, which involves premature activation of the parturition cascade in the reproductive tissues. Herein, we utilize single-cell RNA sequencing (scRNA-seq) to generate a single-cell atlas of the murine uterus, decidua, and cervix in a model of infection-induced preterm labor. We show that preterm labor affects the transcriptomic profiles of specific immune and non-immune cell subsets. Shared and tissue-specific gene expression signatures are identified among affected cells. Determination of intercellular communications implicates specific cell types in preterm labor-associated signaling pathways across tissues. In silico comparison of murine and human uterine cell-cell interactions reveals conserved signaling pathways implicated in labor. Thus, our scRNA-seq data provide insights into the preterm labor-driven cellular landscape and communications in reproductive tissues.

Something Smells Fishy: How Lipid Mediators Impact the Maternal-Fetal Interface and Neonatal Development

Normal pregnancy relies on inflammation for implantation, placentation, and parturition, but uncontrolled inflammation can lead to poor maternal and infant outcomes. Maternal diet is one modifiable factor that can impact inflammation. Omega-3 and -6 fatty acids obtained through the diet are metabolized into bioactive compounds that effect inflammation. Recent evidence has shown that the downstream products of omega-3 and -6 fatty acids may influence physiology during pregnancy. In this review, the current knowledge relating to omega-3 and omega-6 metabolites during pregnancy will be summarized.

Immune transcriptional profiles in mothers with clinically elevated depression and anxiety symptoms several years post-delivery

BACKGROUND

Most research on maternal mental health focuses on the perinatal period and does not extend beyond 12 months postpartum. However, emerging evidence suggests that for some women (30%-50%), psychological symptoms may persist beyond the first year postpartum or even emerge later increasing the risk of chronic mood and anxiety symptoms. Despite the high prevalence rates and devastating maternal-child consequences, studies examining maternal depression, anxiety, and post-traumatic stress disorder (PTSD) beyond the first year postpartum are rare and our understanding of the underlying biological mechanisms is incomplete. Inflammatory processes are thought to be involved in the pathophysiology of depression, anxiety, & PTSD outside of the postpartum period. Therefore, the purpose of the current investigation was to examine the relationship between depression, anxiety, and PTSD two to three years post-delivery, and transcriptional control pathways relevant to inflammatory and antiviral processes.

METHODS

Women over 18 years of age enrolled in ongoing research studies at Cedars Sinai Medical Center who were 2-3 years postpartum were invited to participate in the current study. Women (N = 33) reported on their levels of depression, anxiety, and PTSD and provided a blood sample approximately 2-3 years post-delivery. Bioinformatic analyses of differential gene expression (DGEs) to infer transcription factor activity were used. Gene expression was assayed by RNA sequencing and TELiS bioinformatics analysis of transcription factor-binding motifs in the promoters of differentially expressed genes.

RESULTS

DGE analyses revealed that women with clinically elevated symptoms of depression, anxiety and PTSD (n = 16) showed upregulation of genes activated by transcription control pathways associated with inflammation (NF-_Κ B, p = 0.004; JUN, p = 0.02), including ꞵ-adrenergic responsive CREB (p = 0.01) and reduced activation of genes associated with the antiviral response (IRFs, p = 0.02) and the glucocorticoid signaling pathway (GR, p = 0.02) compared to women without clinical symptoms (n = 17).

CONCLUSIONS

This is one of the first investigations into the immune signaling pathways involved in depression, anxiety, and PTSD two to three years post-delivery. The results of this study suggest that clinically elevated symptoms of depression, anxiety, and PTSD two to three years post-delivery are associated with a gene expression profile characterized by upregulated expression of pro-inflammatory genes and downregulated expression of antiviral genes. The data also point to two potential stress responsive pathways linking symptoms to increased inflammatory signaling in immune cells: sympathetic nervous system mediated ꞵ-adrenergic signaling and reduced hypothalamic pituitary adrenal axis activity. Together, these findings highlight the need for investigations into maternal mental health beyond the first year postpartum. This article is protected by copyright. All rights reserved.

Understanding the Immune System in Fetal Protection and Maternal Infections during Pregnancy

The fetal-maternal immune system determines the fate of pregnancy. The trophoblast cells not only give an active response against external stimuli but are also involved in secreting most of the cytokines. These cells have an essential function in fetal acceptance or fetal rejection. Other immune cells also play a pivotal role in carrying out a successful pregnancy. The disruption in this mechanism may lead to harmful effects on pregnancy. The placenta serves as an immune barrier in fetus protection against invading pathogens. Once the infections prevail, they may localize in placental and fetal tissues, and the presence of inflammation due to cytokines may have detrimental effects on pregnancy. Moreover, some pathogens are responsible for congenital fetal anomalies and affect almost all organs of the developing fetus. This review article is designed to address the bacterial and viral infections that threaten pregnancy and their possible outcomes. Moreover, training of the fetal immune system against the exposure of infections and the role of CD49a + NK cells in embryonic development will also be highlighted.

Clarithromycin prevents preterm birth and neonatal mortality by dampening alarmin-induced maternal–fetal inflammation in mice

Background

One of every four preterm neonates is born to a woman with sterile intra-amniotic inflammation (inflammatory process induced by alarmins); yet, this clinical condition still lacks treatment. Herein, we utilized an established murine model of sterile intra-amniotic inflammation induced by the alarmin high-mobility group box-1 (HMGB1) to evaluate whether treatment with clarithromycin prevents preterm birth and adverse neonatal outcomes by dampening maternal and fetal inflammatory responses.

Methods

Pregnant mice were intra-amniotically injected with HMGB1 under ultrasound guidance and treated with clarithromycin or vehicle control, and pregnancy and neonatal outcomes were recorded (n = 15 dams each). Additionally, amniotic fluid, placenta, uterine decidua, cervix, and fetal tissues were collected prior to preterm birth for determination of the inflammatory status (n = 7–8 dams each).

Results

Clarithromycin extended the gestational length, reduced the rate of preterm birth, and improved neonatal mortality induced by HMGB1. Clarithromycin prevented preterm birth by interfering with the common cascade of parturition as evidenced by dysregulated expression of contractility-associated proteins and inflammatory mediators in the intra-uterine tissues. Notably, clarithromycin improved neonatal survival by dampening inflammation in the placenta as well as in the fetal lung, intestine, liver, and spleen.

Conclusions

Clarithromycin prevents preterm birth and improves neonatal survival in an animal model of sterile intra-amniotic inflammation, demonstrating the potential utility of this macrolide for treating women with this clinical condition, which currently lacks a therapeutic intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04764-2.

Salicornia herbacea Aqueous Extracts Regulate NLRP3 Inflammasome Activation in Macrophages and Trophoblasts

Salicornia herbacea L. (Chenopodiaceae), an edible salt marsh plant with anti-inflammatory effects, was examined in macrophages and trophoblasts whether it modulates NLRP3 inflammasome activity. Pretreatment and delayed treatment of S. herbacea extract (SHE) in bone marrow-derived macrophages (BMDMs) reduced the activity of NLRP3 inflammasome induced by lipopolysaccharide (LPS) and adenosine triphosphate stimulation and downregulated interleukin (IL)-1β production. SHE also inhibited pyroptotic cell death, the adaptor molecule apoptosis-associated speck-like protein containing a CARD (ASC), oligomerization, and speck by NLRP3 inflammasome activity in BMDM. Similarly, SHE decreased the mRNA expression of NLRP3, ASC, IL-1β, and IL-6 in the LPS-stimulated human trophoblast cell line, Swan 71 cells. In addition, SHE inhibited the production of IL-6 and IL-1β and decreased the expression of cyclooxygenase-2 and prostaglandin E2 in stimulated Swan 71 cells. Finally, 3,5-dicaffeoylquinic acid (3,5-DCQA), one of the components of S. herbacea, inhibited IL-1β produced by NLRP3 inflammasome activity. In conclusion, SHE downregulated the activity of the NLRP3 inflammasome in macrophages and trophoblasts.

Myometrial-derived CXCL12 promotes lipopolysaccharide induced preterm labour by regulating macrophage migration, polarization and function in mice

Preterm birth is a major contributor to neonatal mortality and morbidity. Infection results in elevation of inflammation-related cytokines followed by infiltration of immune cells into gestational tissue. CXCL12 levels are elevated in preterm birth indicating it may have a role in preterm labour (PTL); however, the pathophysiological correlations between CXCL12/CXCR4 signalling and premature labour are poorly understood. In this study, PTL was induced using lipopolysaccharide (LPS) in a murine model. LPS induced CXCL12 RNA and protein levels significantly and specifically in myometrium compared with controls (3-fold and 3.5-fold respectively). Highest levels were found just before the start of labour. LPS also enhanced the infiltration of neutrophils, macrophages and T cells, and induced macrophage M1 polarization. In vitro studies showed that condition medium from LPS-treated primary smooth muscle cells (SMC) induced macrophage migration, M1 polarization and upregulated inflammation-related cytokines such as interleukin (IL)-1, IL-6 and tumor necrosis factor alpha (TNF-α). AMD3100 treatment in pregnant mice led to a significant decrease in the rate of PTL (70%), prolonged pregnancy duration and suppressed macrophage infiltration into gestation tissue by 2.5-fold. Further, in-vitro treatment of SMC by AMD3100 suppressed the macrophage migration, decreased polarization and downregulated IL-1, IL-6 and TNF-α expression. LPS treatment in pregnant mice induced PTL by increasing myometrial CXCL12, which recruits immune cells that in turn produce inflammation-related cytokines. These effects stimulated by LPS were completely reversed by AMD3100 through blocking of CXCL12/CXCR4 signalling. Thus, the CXCL12/CXCR4 axis presents an excellent target for preventing infection and inflammation-related PTL.

Genital Mycoplasmas and Biomarkers of Inflammation and Their Association With Spontaneous Preterm Birth and Preterm Prelabor Rupture of Membranes: A Systematic Review and Meta-Analysis

Genital mycoplasmas (GM), such as Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma parvum, and Ureaplasma urealyticum are commonly associated with spontaneous preterm labor (SPTL), spontaneous preterm birth (PTB), and preterm prelabor rupture of membranes (PPROM). This study determined the association between GM and such adverse pregnancy outcomes. We searched for studies published 1980–2019 in MEDLINE, EMBASE, and Web of Science. Studies were eligible when GM was detected during pregnancy. We included 93 and 51 studies in determining the prevalence and the inflammatory biomarkers associated with GM, respectively, using the “metafor” package within R. The protocol was registered with PROSPERO (registration no. CRD42016047297). Women with the studied adverse pregnancy outcomes had significantly higher odds of presence with GM compared to women who delivered at term. For PTB, the odds ratios were: M. hominis (OR: 2.25; CI: 1.35–3.75; I²: 44%), M. genitalium (OR: 2.04; CIL 1.18–3.53; I²: 20%), U. parvum (OR: 1.75; CI: 1.47–2.07; I²: 0%), U. urealyticum (OR: 1.50; CI: 1.08–2.07; I²: 58%). SPTL had significantly higher odds with M. hominis (OR: 1.96; CI: 1.19–3.23; I²: 1%) or U. urealyticum (OR: 2.37; CI: 1.20–4.70; I²: 76%) compared to women without SPTL. Women with PPROM had significantly higher odds with M. hominis (OR: 2.09; CI: 1.42–3.08; I²: 0%) than women without PPROM. However, our subgroup analysis based on the diagnostic test and the sample used for detecting GM showed a higher prevalence of GM in maternal samples than in fetal samples. GM presence of the cervix and vagina was associated with lower odds of PTB and preterm labor (PTL). In contrast, GM presence in the AF, fetal membrane, and placenta was associated with increased odds of PTB and PTL. However, genital mycoplasmas may not elicit the massive inflammation required to trigger PTB. In conclusion, GM presence in the fetal tissues was associated with significantly increased odds of PTB and PTL.

Downregulation of miR-21 is Involved in the Pathogenesis of Infection-Induced Preterm Birth by Targeting NF-κB

Infection-induced preterm birth (PTB) is contributing to the main factors of increased maternal and fetal morbidity and mortality. Infections and inflammation are often accompanied by histologic chorioamnionitis. Recently, several studies have uncovered that miR-21 and NF-κB are associated with pathological processes of pregnant women. However, the role of miR-21 in infection-induced PTB remains unclear. This study aimed to determine whether miR-21 is involved in the pathogenesis of infection-induced PTB by regulating NF-κB. In this study, we found that the expression of miR-21 was significantly decreased in placental tissues of lipopolysaccharides (LPS)-induced infectious PTB mice model, accompanied by the increase of NF-κB, IL-6, and TNF-α (P < 0.05). Luciferase reporter gene assays showed that NF-κB was a validated target of miR-21. Furthermore, cell transfection experiments showed that miR-21 overexpression significantly decreased NF-κB mRNA expression compared with the miR-control group and blank group. Conversely, miR-21 inhibitor can enhance NF-κB mRNA expression. After the treatment of miR-21 mimics, miR-21 expression was obviously increased compared with the LPS group, accompanied by the decrease of NF-κB, TNF-α, and IL-6 mRNA expression (P < 0.05). What's more, miR-21 expression was negatively correlated with NF-κB (r=-0.87, P < 0.01). Overall, the study findings indicate that miR-21 may contribute to the pathogenesis of infection-induced PTB by upregulating the target NF-κB and that miR-21 may be a new potential therapeutic target for infection-induced PTB.

Study of Treatment and Reproductive Outcomes Among Reproductive-Age Women With HIV Infection in the Southern United States: Protocol for a Longitudinal Cohort Study

BACKGROUND

Nearly a quarter of the 1.1 million individuals with HIV in the United States are women. Racial and ethnic minority women in the Southern United States are disproportionately impacted. Reproductive-age women with HIV are prone to poor HIV outcomes but remain underrepresented in HIV research. We will answer contemporary questions related to the health outcomes in this population by enrolling a prospective cohort of reproductive-age women with and without HIV in the Southern United States.

OBJECTIVE

The Study of Treatment and Reproductive Outcomes (STAR) will enroll and retain 2000 reproductive-age women with and without HIV. The STAR will leverage the infrastructure of the US-based Multicenter AIDS Cohort Study (MACS)/Women's Interagency HIV Study (WIHS) Combined Cohort Study, comprising the WIHS (a cohort of women with and at risk for HIV, which began in 1993), and the MACS (a cohort of gay and bisexual men with and at risk for HIV, which began in 1984). Although the advancing age of the participants enrolled in the MACS/WIHS Combined Cohort Study provides an opportunity to address the questions related to HIV and aging, the research questions pertinent to the reproductive years must also be addressed. The STAR will conduct high-priority scientific research in key areas with the overall aim of addressing the unique needs of reproductive-age women with HIV.

METHODS

The STAR is a prospective, observational cohort study that will be conducted at 6 sites in the United States-Atlanta, Georgia; Birmingham, Alabama; Jackson, Mississippi; Chapel Hill, North Carolina; Miami, Florida; and Washington, District of Columbia. Visits will occur semiannually for 2 years, with additional visits for up to 5 years. At each visit, the participating women will complete a structured interview for collecting key demographic, psychosocial, and clinical variables, and undergo biospecimen collection for laboratory testing and repositing (blood, urine, hair, vaginal, anal, and oral specimens). Pregnant women and infants will undergo additional study assessments. The initial scientific focus of the STAR is to understand the roles of key social determinants of health, depression, reproductive health, and oral health on HIV and pregnancy outcomes across the reproductive life span.

RESULTS

Enrollment in the STAR commenced in February 2021 and is ongoing.

CONCLUSIONS

Through in-depth, longitudinal data and biospecimen collection, the newly initiated STAR cohort will create a platform to answer scientific questions regarding reproductive-age women with and without HIV. STAR will be uniquely positioned to enable investigators to conduct high-impact research relevant to this population. Building on the legacy of the MACS and WIHS cohorts, the STAR is designed to foster multidisciplinary collaborations to galvanize scientific discoveries to improve the health of reproductive-age women with HIV and ameliorate the effects of the HIV epidemic in this population in the United States.

Association of Maternal Inflammation During Pregnancy With Birth Outcomes and Infant Growth Among Women With or Without HIV in India

IMPORTANCE

The association of elevated levels of specific inflammatory markers during pregnancy with adverse birth outcomes and infant growth could indicate pathways for potential interventions.

OBJECTIVE

To evaluate whether higher levels of certain inflammatory markers during pregnancy are associated with preterm birth (PTB), low birth weight (LBW), and infant growth deficits.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study of pregnant women with or without HIV, 218 mother-infant pairs were followed up from pregnancy through 12 months post partum from June 27, 2016, to December 9, 2019. Pregnant women aged 18 to 40 years and between 13 and 34 weeks of gestation who were receiving antenatal care were enrolled in a cohort stratified by HIV status; sampling was based on convenience sampling from women receiving antenatal care at Byramjee Jeejeebhoy Government Medical College.

EXPOSURES

Levels of multiple circulating inflammation markers during the third trimester of pregnancy.

MAIN OUTCOMES AND MEASURES

The primary study outcome was PTB (<37 weeks' gestation). Secondary outcomes were LBW (<2500 g) and repeated measures (delivery; 6 weeks post partum; and 3, 6, and 12 months post partum using multivariable generalized linear models) of infant growth outcomes (length-for-age, weight-for-age, and weight-for-length z scores).

RESULTS

The median age of the 218 women at enrollment was 23 years (IQR, 21-27 years). In multivariable models, higher pregnancy levels of interleukin 17A were associated with increased odds of both PTB (adjusted odds ratio [aOR], 2.62; 95% CI, 1.11-6.17) and LBW (aOR, 1.81; 95% CI, 1.04-3.15). Higher levels of interleukin 1β were associated with increased PTB (aOR, 1.47; 95% CI, 1.15-1.89) and infant growth deficits (lower length-for-age z score: adjusted β = -0.10; 95% CI, -0.18 to -0.01; lower weight-for-age z score: adjusted β = -0.07; 95% CI, -0.14 to 0.001).

CONCLUSIONS AND RELEVANCE

This study suggests that increased levels of certain systemic inflammatory markers, including interleukin 1β and interleukin 17A, during pregnancy were associated with adverse birth outcomes and infant growth deficits. Future studies should evaluate whether potential interventions to modulate specific inflammatory pathways during pregnancy could improve birth outcomes and infant growth.

Placental extracellular vesicles-associated microRNA-519c mediates endotoxin adaptation in pregnancy

BACKGROUND

Pregnancy represents a unique challenge for the maternal-fetal immune interface, requiring a balance between immunosuppression, which is essential for the maintenance of a semiallogeneic fetus, and proinflammatory host defense to protect the maternal-fetal interface from invading organisms. Adaptation to repeated inflammatory stimuli (endotoxin tolerance) may be critical in preventing inflammation-induced preterm birth caused by exaggerated maternal inflammatory responses to mild or moderate infections that are common during pregnancy. However, the exact mechanisms contributing to the maintenance of tolerance to repeated infections are not completely understood. MicroRNAs play important roles in pregnancy with several microRNAs implicated in gestational tissue function and in pathologic pregnancy conditions. MicroRNA-519c, a member of the chromosome 19 microRNA cluster, is a human-specific microRNA mainly expressed in the placenta. However, its role in pregnancy is largely unknown.

OBJECTIVE

This study aimed to explore the role of "endotoxin tolerance" failure in the pathogenesis of an exaggerated inflammatory response often seen in inflammation-mediated preterm birth. In this study, we investigated the role of microRNA-519c, a placenta-specific microRNA, as a key regulator of endotoxin tolerance at the maternal-fetal interface.

STUDY DESIGN

Using a placental explant culture system, samples from term and second-trimester placentas were treated with lipopolysaccharide. After 24 hours, the conditioned media were collected for analysis, and the placental explants were re-exposed to repeated doses of lipopolysaccharide for 3 days. The supernatant was analyzed for inflammatory markers, the presence of extracellular vesicles, and microRNAs. To study the possible mechanism of action of the microRNAs, we evaluated the phosphodiesterase 3B pathway involved in tumor necrosis factor alpha production using a microRNA mimic and phosphodiesterase 3B small interfering RNA transfection. Finally, we analyzed human placental samples from different gestational ages and from women affected by inflammation-associated pregnancies.

RESULTS

Our data showed that repeated exposure of the human placenta to endotoxin challenges induced a tolerant phenotype characterized by decreased tumor necrosis factor alpha and up-regulated interleukin-10 levels. This reaction was mediated by the placenta-specific microRNA-519c packaged within placental extracellular vesicles. Lipopolysaccharide treatment increased the extracellular vesicles that were positive for the exosome tetraspanin markers, namely CD9, CD63, and CD81, and secreted primarily by trophoblasts. Primary human trophoblast cells transfected with a microRNA-519c mimic decreased phosphodiesterase 3B, whereas a lack of phosphodiesterase 3B, achieved by small interfering RNA transfection, led to decreased tumor necrosis factor alpha production. These data support the hypothesis that the anti-inflammatory action of microRNA-519c was mediated by a down-regulation of the phosphodiesterase 3B pathway, leading to inhibition of tumor necrosis factor alpha production. Furthermore, human placentas from normal and inflammation-associated pregnancies demonstrated that a decreased placental microRNA-519c level was linked to infection-induced inflammatory pathologies during pregnancy.

CONCLUSION

We identified microRNA-519c, a human placenta-specific microRNA, as a novel regulator of immune adaptation associated with infection-induced preterm birth at the maternal-fetal interface. Our study serves as a basis for future experiments to explore the potential use of microRNA-519c as a biomarker for infection-induced preterm birth.

Endocrine disrupting chemical-associated hair product use during pregnancy and gestational age at delivery: a pilot study

BACKGROUND

Prenatal endocrine disrupting chemical (EDC) exposure has been associated with increased risk of preterm birth. Non-Hispanic Black women have higher incidence of preterm birth compared to other racial/ethnic groups and may be disproportionately exposed to EDCs through EDC-containing hair products. However, research on the use of EDC-associated hair products during pregnancy and risk of preterm birth is lacking. Therefore, the objective of this pilot study was to estimate associations of prenatal hair product use with gestational age at delivery in a Boston, Massachusetts area pregnancy cohort.

METHODS

The study population consisted of a subset of participants enrolled in the Environmental Reproductive and Glucose Outcomes (ERGO) Study between 2018 and 2020. We collected self-reported data on demographics and hair product use using a previously validated questionnaire at four prenatal visits (median: 12, 19, 26, 36 weeks' gestation) and abstracted gestational age at delivery from medical records. We compared gestational age and hair product use by race/ethnicity and used linear regression to estimate covariate-adjusted associations of product use and frequency of use at each study visit with gestational age at delivery. Primary models were adjusted for maternal age at enrollment and delivery method.

RESULTS

Of the 154 study participants, 7% delivered preterm. Non-Hispanic Black participants had lower mean gestational age at delivery compared to non-Hispanic White participants (38.2 vs. 39.2 weeks) and were more likely to report ever and more frequent use of hair products. In regression models, participants reporting daily use of hair oils at visit 4 had lower mean gestational age at delivery compared to non-users (β: -8.3 days; 95% confidence interval: -14.9, -1.6). We did not find evidence of associations at earlier visits or with other products.

CONCLUSIONS

Frequent use of hair oils during late pregnancy may be associated with shorter gestational duration. As hair oils are more commonly used by non-Hispanic Black women and represent potentially modifiable EDC exposure sources, this may have important implications for the known racial disparity in preterm birth.

Sex Differences Are Here to Stay: Relevance to Prenatal Care

Sex differences exist in the incidence and presentation of many pregnancy complications, including but not limited to pregnancy loss, spontaneous preterm birth, and fetal growth restriction. Sex differences arise very early in development due to differential gene expression from the X and Y chromosomes, and later may also be influenced by the action of gonadal steroid hormones. Though offspring sex is not considered in most prenatal diagnostic or therapeutic strategies currently in use, it may be beneficial to consider sex differences and the associated mechanisms underlying pregnancy complications. This review will cover (i) the prevalence and presentation of sex differences that occur in perinatal complications, particularly with a focus on the placenta; (ii) possible mechanisms underlying the development of sex differences in placental function and pregnancy phenotypes; and (iii) knowledge gaps that should be addressed in the development of diagnostic or risk prediction tools for such complications, with an emphasis on those for which it would be important to consider sex.

Maternal Vaginal Ureaplasma spp. Colonization in Early Pregnancy Is Associated with Adverse Short- and Long-Term Outcome of Very Preterm Infants

Vaginal colonization with Ureaplasma (U.) spp. has been shown to be associated with adverse pregnancy outcome; however, data on neonatal outcome are scarce. The aim of the study was to investigate whether maternal vaginal colonization with U. spp. in early pregnancy represents a risk factor for adverse short- or long-term outcome of preterm infants. Previously, 4330 pregnant women were enrolled in an observational multicenter study, analyzing the association between vaginal U. spp. colonization and spontaneous preterm birth. U. spp. colonization was diagnosed via PCR analysis from vaginal swabs. For this study, data on short-term outcome were collected from medical records and long-term outcome was examined via Bayley Scales of Infant Development at 24 months adjusted age. Two-hundred-and-thirty-eight children were born <33 weeks gestational age. After exclusion due to asphyxia, malformations, and lost-to-follow-up, data on short-term and long-term outcome were available from 222 and 92 infants, respectively. Results show a significant association between vaginal U. spp. colonization and severe intraventricular hemorrhage (10.4% vs. 2.6%, p = 0.03), retinopathy of prematurity (21.7% vs. 10.3%, p = 0.03), and adverse psychomotor outcome (24.3% vs. 1.8%, OR 13.154, 95%CI 1.6,110.2, p = 0.005). The data suggest an association between vaginal U. spp. colonization in early pregnancy and adverse short- and long-term outcome of very preterm infants.

Prenatal Maternal Lipopolysaccharide and Mild Newborn Hyperoxia Increase Intrapulmonary Airway but Not Vessel Reactivity in a Mouse Model

Maternal infection is a risk for preterm delivery. Preterm newborns often require supplemental oxygen to treat neonatal respiratory distress. Newborn hyperoxia exposure is associated with airway and vascular hyperreactivity, while the complications of maternal infection are variable. In a mouse model of prenatal maternal intraperitoneal lipopolysaccharide (LPS, embryonic day 18) with subsequent newborn hyperoxia (40% oxygen × 7 days) precision-cut living lung slices were used to measure intrapulmonary airway and vascular reactivity at 21 days of age. Hyperoxia increased airway reactivity to methacholine compared to room air controls. Prenatal maternal LPS did not alter airway reactivity in room air. Combined maternal LPS and hyperoxia exposures increased airway reactivity vs. controls, although maximal responses were diminished compared to hyperoxia alone. Vessel reactivity to serotonin did not significantly differ in hyperoxia or room air; however, prenatal maternal LPS appeared to attenuate vessel reactivity in room air. Following room air recovery, LPS with hyperoxia lungs displayed upregulated inflammatory and fibrosis genes compared to room air saline controls (TNFαR1, iNOS, and TGFβ). In this model, mild newborn hyperoxia increases airway but not vessel reactivity. Prenatal maternal LPS did not further increase hyperoxic airway reactivity. However, inflammatory genes remain upregulated weeks after recovery from maternal LPS and newborn hyperoxia exposures.

Vertical Transmission of Extended-Spectrum, Beta-Lactamase-Producing Enterobacteriaceae during Preterm Delivery: A Prospective Study

Maternal carriage and vertical transmission of extended-spectrum, beta-lactamase-producing Enterobacteriaceae (ESBL-E), such as Escherichia coli, hamper the treatment of infections, resulting in high morbidity. E. coli is the most frequent cause of early-onset neonatal sepsis (EOS) in preterm infants, where ESBL-E are more frequently isolated. In this prospective, case-controlled study, maternal rectovaginal ESBL-E colonization and vertical transmission to preterm infants were assessed in 160 women with preterm premature rupture of membranes (PPROM; 57.4%) or preterm labor (42.6%); additional cultures were obtained from the placenta, amnion, and umbilical cord during preterm labor. Maternal and neonatal ESBL-E-carriage rates were 17.5% and 12.9%, respectively, and the vertical-transmission rate was 50%. Maternal ESBL-E colonization among women with PPROM was 21.3%, and in women with premature labor it was 12.6%. No correlation was observed between maternal ESBL-E-colonization and previous hospitalization or antibiotic administration during pregnancy. However, a correlation was found between placental inflammation and maternal ESBL-E colonization (p = 0.007). ESBL-E-colonized infants were delivered at an earlier gestational age and were more likely to have complications. Thus, the high ESBL-E carriage rate in women with threatened preterm labor, without obvious risk factors for carriage, and a high vertical transmission rate, combined with a correlation between placental inflammation and ESBL-E carriage, support maternal–neonatal ESBL-E-colonization surveillance and active measures to prevent ESBL-E-related EOS.

Reporting of Perinatal Outcomes in Probiotic Randomized Controlled Trials. A Systematic Review and Meta-Analysis

The use of probiotic microorganisms in clinical practice has increased in recent years and a significant number of pregnant women are regular consumers of these products. However, probiotics might modulate the immune system, and whether or not this modulation is beneficial for perinatal outcomes is unclear. We performed a systematic review and meta-analysis to evaluate the reporting of perinatal outcomes in randomized controlled trials including women supplemented with probiotic microorganisms during pregnancy. We also analyzed the effects that the administration of probiotic microorganisms exerts on perinatal outcomes. In the review, 46 papers were included and 25 were meta-analyzed. Reporting of perinatal outcomes was highly inconsistent across the studies. Only birth weight, cesarean section, and weeks of gestation were reported in more than 50% of the studies. Random effects meta-analysis results showed that the administration of probiotic microorganisms during pregnancy did not have any a positive or negative impact on the perinatal outcomes evaluated. Subgroup analysis results at the strain level were not significantly different from main analysis results. The administration of probiotic microorganisms does not appear to influence perinatal outcomes. Nonetheless, future probiotic studies conducted in pregnant women should report probiotic strains and perinatal outcomes in order to shed light upon probiotics’ effects on pregnancy outcomes.

Maternal Progesterone Treatment Reduces Maternal Inflammation-Induced Fetal Brain Injury in a Mouse Model of Preterm Birth

Maternal natural vaginal progesterone (nVP) administration has been shown to reduce the risk of preterm birth (PTB). The largest randomized trial of nVP for PTB (OPPTIMUM) noted a sonographic reduction in neonatal brain injury following nVP treatment. We investigated the neuroinflammatory protective effect of maternal nVP in a mouse model for maternal inflammation. Pregnant mice (n = 24) were randomized to nVP (1 mg/day) or vehicle from days 13-16 of gestation. At days 15 and 16, lipopolysaccharide (30 μg) or saline were administered. Mice were sacrificed 4 h following the last injection. Fetal brains and placentas were collected. Levels of NF-κB, nNOS, IL-6, and TNFα were determined by Western blot. Maternal lipopolysaccharide significantly increased fetal brain levels of IL-6 (0.33 ± 0.02 vs. 0.11 ± 0.01 u), TNFα (0.3 ± 0.02 vs. 0.10 ± 0.01 u), NF-κB (0.32 ± 0.01 vs. 0.17 ± 0.01 u), and nNOS (0.24 ± 0.04 vs. 0.08 ± 0.01 u), and reduced the total glutathione levels (0.014 ± 0.001 vs. 0.026 ± 0.001 pmol/μl; p < 0.01) compared with control. Maternal nVP significantly reduced fetal brain levels of IL-6 (0.14 ± 0.01 vs. 0.33 ± 0.02 u), TNFα (0.2 ± 0.06 vs. 0.3 ± 0.02 u), NF-κB (0.16 ± 0.01 vs 0.32 ± 0.01 u), and nNOS (0.14 ± 0.01 vs 0.24 ± 0.04 u), and prevented the reduction of fetal brain total glutathione levels (0.022 ± 0.001 vs. 0.014 ± 0.001 pmol/μl; p < 0.01) to levels similar to controls. A similar pattern was demonstrated in the placenta. Maternal nVP for PTB may protect the fetal brain from inflammation-induced brain injury by inhibiting specific inflammatory and oxidative pathways in both brain and placenta.

Modeling ascending infection with a feto-maternal interface organ-on-chip

Maternal infection (i.e., ascending infection) and the resulting host inflammatory response are risk factors associated with spontaneous preterm birth (PTB), a major pregnancy complication. However, the path of infection and its propagation from the maternal side to the fetal side have been difficult to study due to the lack of appropriate in vitro models and limitations of animal models. A better understanding of the propagation kinetics of infectious agents and development of the host inflammatory response at the feto-maternal (amniochorion-decidua, respectively) interface (FMi) is critical in curtailing host inflammatory responses that can lead to PTB. To model ascending infection and determine inflammatory responses at the FMi, we developed a microfluidic organ-on-chip (OOC) device containing primary cells from the FMi (decidua, chorion, and amnion [mesenchyme and epithelium]) and collagen matrix harvested from primary tissue. The FMi-OOC is composed of four concentric circular cell/collagen chambers designed to mimic the thickness and cell density of the FMi in vivo. Each layer is connected by arrays of microchannels filled with type IV collagen to recreate the basement membrane of the amniochorion. Cellular characteristics (viability, morphology, production of nascent collagen, cellular transitions, and migration) in the OOC were similar to those seen in utero, validating the physiological relevance and utility of the developed FMi-OOC. The ascending infection model of the FMi-OOC, triggered by exposing the maternal (decidua) side of the OOC to lipopolysaccharide (LPS, 100 ng mL-1), shows that LPS propagated through the chorion, amnion mesenchyme, and reached the fetal amnion within 72 h. LPS induced time-dependent and cell-type-specific pro-inflammatory cytokine production (24 h decidua: IL-6, 48 h chorion: GM-CSF and IL-6, and 72 h amnion mesenchyme and epithelium: GM-CSF and IL-6). Collectively, this OOC model and study successfully modeled ascending infection, its propagation, and distinct inflammatory response at the FMi indicative of pathologic pathways of PTB. This OOC model provides a novel platform to study physiological and pathological cell status at the FMi, and is expected to have broad utility in the field of obstetrics.

RNA Sequencing Reveals Diverse Functions of Amniotic Fluid Neutrophils and Monocytes/Macrophages in Intra-Amniotic Infection

Intra-amniotic infection, the invasion of microbes into the amniotic cavity resulting in inflammation, is a clinical condition that can lead to adverse pregnancy outcomes for the mother and fetus as well as severe long-term neonatal morbidities. Despite much research focused on the consequences of intra-amniotic infection, there remains little knowledge about the innate immune cells that respond to invading microbes. We performed RNA-seq of sorted amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection to determine the transcriptomic differences between these innate immune cells. Further, we sought to identify specific transcriptomic pathways that were significantly altered by the maternal or fetal origin of amniotic fluid neutrophils and monocytes/macrophages, the presence of a severe fetal inflammatory response, and pregnancy outcome (i.e., preterm or term delivery). We show that significant transcriptomic differences exist between amniotic fluid neutrophils and monocytes/macrophages from women with intra-amniotic infection, indicating the distinct roles these cells play. The transcriptome of amniotic fluid immune cells varies based on their maternal or fetal origin, and the significant transcriptomic differences between fetal and maternal monocytes/macrophages imply that those of fetal origin exhibit impaired functions. Notably, transcriptomic changes in amniotic fluid monocytes/macrophages suggest that these immune cells collaborate with neutrophils in the trafficking of fetal leukocytes throughout the umbilical cord (i.e., funisitis). Finally, amniotic fluid neutrophils and monocytes/macrophages from preterm deliveries display enhanced transcriptional activity compared to those from term deliveries, highlighting the protective role of these cells during this vulnerable period. Collectively, these findings demonstrate the underlying complexity of local innate immune responses in women with intra-amniotic infection and provide new insights into the functions of neutrophils and monocytes/macrophages in the amniotic cavity.

GrpE Immunization Protects Against Ureaplasma urealyticum Infection in BALB/C Mice

Nucleotide exchange factor (GrpE), a highly conserved antigen, is rapidly expressed and upregulated when Ureaplasma urealyticum infects a host, which could act as a candidative vaccine if it can induce an anti-U. urealyticum immune reaction. Here, we evaluated the vaccine potential of recombinant GrpE protein adjuvanted by Freund's adjuvant (FA), to protect against U. urealyticum genital tract infection in a mouse model. After booster immunization in mice with FA, the GrpE can induced both humoral and cellular immune response after intramuscular injection into BALB/c mice. A strong humoral immune response was detected in the GrpE-immunized mice characterized by production of high titers of antigen-specific serum IgG (IgG1, IgG2a, and IgG3) antibodies. At the same time, the GrpE also induced a Th1-biased cytokine spectrum with high levels of IFN-γ and TNF-α after re-stimulation with immunogen GrpE in vitro, suggesting that GrpE could trigger the Th1 response when used for vaccination in the presence of FA. Although GrpE vaccination in the presence of a Th1-type adjuvant-induced had readily detectable Th1 responses, there wasn't increase inflammation in response to the infection. More importantly, the robust immune responses in mice after immunization with GrpE showed a significantly reduced U. urealyticum burden in cervical tissues. Histopathological analysis confirmed that tissues of GrpE-immunized BALB/c mice were protected against the pathological effects of U. urealyticum infection. In conclusion, this study preliminarily reveals GrpE protein as a promising new candidate vaccine for preventing U. urealyticum reproductive tract infection.

Does Low Maternal Exposure to Per- and Polyfluoroalkyl Substances Elevate the Risk of Spontaneous Preterm Birth? A Nested Case-Control Study in China

Previous animal and human studies suggest potential links between maternal exposure to per- and polyfluoroalkyl substances (PFASs) and adverse birth outcomes. As spontaneous preterm birth (SPB) represents a major cause of infant mortality and precursor to future morbidity, we conducted a prospective nested case-control study in Shanxi Province, China to investigate the association between prenatal PFAS exposure and SPB risk, as well as the associations with biomarkers of oxidative stress and systemic inflammation. Among 4229 women enrolled during 2009-2013, 144 SPB cases and 375 controls were included in this study. Seventeen PFASs, as well as monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), and heme oxygenase-1 (HO-1), were measured in maternal plasma or serum collected during 4th-22nd gestational weeks. Perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and its alternative chlorinated polyfluoroether sulfonic acid (6:2 Cl-PFESA) were detected in more than 90% samples with a median concentration of 0.79, 1.79, and 0.34 ng/mL, respectively. The analyses revealed no significant associations between plasma PFASs and the SPB risk after adjusting for potential confounders. However, concentrations of PFOS and 6:2 Cl-PFESA were both significantly and positively associated with MCP-1 levels, while PFOA was inversely associated with IL-8. Our findings suggested that maternal exposure to the determined low levels of PFAS did not induce an elevated risk of SPB, but the exposure may disturb potential biochemical pathways of inflammation. The latter has important implications for possible birth outcome effects and developmental effects in fetuses and newborns, which warrants close attention.

New Australian birthweight centiles

OBJECTIVES

To prepare more accurate population-based Australian birthweight centile charts by using the most recent population data available and by excluding pre-term deliveries by obstetric intervention of small for gestational age babies.

DESIGN

Population-based retrospective observational study.

SETTING

Australian Institute of Health and Welfare National Perinatal Data Collection.

PARTICIPANTS

All singleton births in Australia of 23-42 completed weeks' gestation and with spontaneous onset of labour, 2004-2013. Births initiated by obstetric intervention were excluded to minimise the influence of decisions to deliver small for gestational age babies before term.

MAIN OUTCOME MEASURES

Birthweight centile curves, by gestational age and sex.

RESULTS

Gestational age, birthweight, sex, and labour onset data were available for 2 807 051 singleton live births; onset of labour was spontaneous for 1 582 137 births (56.4%). At pre-term gestational ages, the 10th centile was higher than the corresponding centile in previous Australian birthweight charts based upon all births.

CONCLUSION

Current birthweight centile charts probably underestimate the incidence of intra-uterine growth restriction because obstetric interventions for delivering pre-term small for gestational age babies depress the curves at earlier gestational ages. Our curves circumvent this problem by excluding intervention-initiated births; they also incorporate more recent population data. These updated centile curves could facilitate more accurate diagnosis of small for gestational age babies in Australia.

Variable Responsiveness to Agonists for TLR2 and TLR7 in Myometrial Cells from Different Sources: Correlation with Receptor Expression

The myometrium plays a vital role in maintenance of pregnancy. Disruption of myometrial sensitivity to pro-contractile stimuli might lead to preterm labor. Inflammation and/or infection are common precursors to preterm birth, in part by initiating pro-contractile stimuli through toll-like receptor (TLRs) activation. In this study, we investigated the responses specific to inflammatory stimuli for both human primary myometrial cells (HPMCs) and PHM1-41 cells, a human immortalized myometrial cell line. Both these types of cells are commonly used to study labor and pregnancy. Both cell lines were treated with lipopolysaccharide (LPS), peptidoglycan (PGN), or imiquimod (IQ) (ligands for TLRs 2, 4, and 7, respectively). We demonstrate that inflammatory cytokines increase significantly with LPS treatment; however, no change occurs with PGN and IQ, suggesting lack of TLR2- and TLR7-specific signaling in both HPMCs and in the PHM1-41 cell line. Absence of TLR2- and TLR7-specific protein bands on western blots confirmed the lack of these receptors in both HPMCs maintained in long-term culture and PHM1-41 cells. However, TLR2 expression was present in freshly collected matched human myometrial tissue (i.e., the tissues used to create the HPMC cultures), showing loss of TLR2 receptors by HPMCs during the cell culturing process. TLR7 protein expression was lacking both in myometrial tissue and in cultured cells. These results demonstrate the limited applicability and reliability of cellular models to investigate the role of the myometrium during pregnancy and labor.

Compartmentalized profiling of amniotic fluid cytokines in women with preterm labor

Objective

Amniotic fluid cytokines have been implicated in the mechanisms of preterm labor and birth. Cytokines can be packaged within or on the surface of extracellular vesicles. The main aim of this study was to test whether the protein abundance internal to and on the surface of extracellular vesicles changes in the presence of sterile intra-amniotic inflammation and proven intra-amniotic infection in women with preterm labor as compared to the women with preterm labor without either intra-amniotic inflammation or proven intra-amniotic infection.

Study design

Women who had an episode of preterm labor and underwent an amniocentesis for the diagnosis of intra-amniotic infection or intra-amniotic inflammation were classified into three groups: 1) preterm labor without either intra-amniotic inflammation or proven intra-amniotic infection, 2) preterm labor with sterile intra-amniotic inflammation, and 3) preterm labor with intra-amniotic infection. The concentrations of 38 proteins were determined on the extracellular vesicle surface, within the vesicles, and in the soluble fraction of amniotic fluid.

Results

1) Intra-amniotic inflammation, regardless of detected microbes, was associated with an increased abundance of amniotic fluid cytokines on the extracellular vesicle surface, within vesicles, and in the soluble fraction. These changes were most prominent in women with proven intra-amniotic infection. 2) Cytokine changes on the surface of extracellular vesicles were correlated with those determined in the soluble fraction; yet the magnitude of the increase was significantly different between these compartments. 3) The performance of prediction models of early preterm delivery based on measurements on the extracellular vesicle surface was equivalent to those based on the soluble fraction.

Conclusions

Differential packaging of amniotic fluid cytokines in extracellular vesicles during preterm labor with sterile intra-amniotic inflammation or proven intra-amniotic infection is reported herein for the first time. The current study provides insights into the biology of the intra-amniotic fluid ad may aid in the development of biomarkers for obstetrical disease.

Maternal vascular malperfusion in spontaneous preterm birth placentas related to clinical outcome of subsequent pregnancy

INTRODUCTION

Spontaneous preterm birth (SPTB) has several causes and its pathophysiology remains unclear. In a significant proportion of SPTB, placental histology shows signs of maternal vascular malperfusion (MVM); commonly associated with hypertensive disorders of pregnancy (HD), fetal growth restriction (FGR) and placental abruption, together referred to as clinical ischemic placental diseases (IPD). We hypothesized that women with SPTB and placental MVM are at elevated risk for IPD in a subsequent pregnancy.

METHODS

We included women with SPTB in our cohort and followed the subsequent ongoing pregnancy (n = 110). Histological placental characteristics in the index were reported according to new international guidelines, and related to the clinical outcome of the subsequent pregnancy.

RESULTS

In the SPTB placentas, we observed MVM in 61.8% (n = 68). In the subsequent pregnancies in 19.1% (n = 21) at least one clinical sign of IPD was present (HD (12.7%), FGR (5.5%) or placental abruption (0.9%)). There was no significant difference in the prevalence of clinical IPD or recurrence of SPTB in the subsequent pregnancy between women with and without placental MVM in the index pregnancy, although our study was not powered to detect small differences.

DISCUSSION

Women with a history of SPTB have an elevated risk of IPD in the subsequent pregnancy. MVM is present in a large proportion of SPTB placentas. The presence of placental MVM in the index pregnancy does not predict clinical IPD or recurrent SPTB in a subsequent pregnancy.

Mouse models of preterm birth: suggested assessment and reporting guidelines

Preterm birth affects approximately 1 out of every 10 births in the United States, leading to high rates of mortality and long-term negative health consequences. To investigate the mechanisms leading to preterm birth so as to develop prevention strategies, researchers have developed numerous mouse models of preterm birth. However, the lack of standard definitions for preterm birth in mice limits our field's ability to compare models and make inferences about preterm birth in humans. In this review, we discuss numerous mouse preterm birth models, propose guidelines for experiments and reporting, and suggest markers that can be used to assess whether pups are premature or mature. We argue that adoption of these recommendations will enhance the utility of mice as models for preterm birth.

Probiotic Supplementation During Human Pregnancy Affects the Gut Microbiota and Immune Status

The consumption of probiotics and fermented foods has been very popular in recent decades. The primary aim of our study was to evaluate the effect of probiotics on the gut microbiota and the changes in inflammatory cytokines after an average of 6.7 weeks of probiotic administration among normal pregnant women. Thirty-two healthy pregnant women at 32 weeks of gestation were recruited and divided into two groups. The probiotic group ingested combined probiotics until after birth. The base characteristics of the probiotics and control groups showed no significant differences. The structure of the fecal microbiota at the genus level varied during the third trimester, and administration of probiotics had no influence on the composition of the fecal microbiota however, many highly abundant taxa and core microbiota at the genus level changed in the probiotic group when compared to the control group. The analysis of cytokines showed that IL-5, IL-6, TNF-α, and GM-CSF had equal levels between the baseline and control groups but were significantly increased after probiotic administration (baseline = control < probiotics). Additionally, levels of IL-1β, IL-2, IL-12, and IFN-γ significantly increased among the three groups (baseline < control < probiotics). This result demonstrated that probiotics helped to shift the anti-inflammatory state to a pro-inflammatory state. The correlation analysis outcome suggested that the relationship between the microbiota and the cytokines was not strain-dependent. The gut microbiota varied during the third trimester. The probiotics demonstrated immunomodulation effects that helped to switch over to a pro-inflammatory immune state in the third trimester, which was important for labor.

Risk of spontaneous preterm birth and fetal growth associates with fetal SLIT2

Spontaneous preterm birth (SPTB) is the leading cause of neonatal death and morbidity worldwide. Both maternal and fetal genetic factors likely contribute to SPTB. We performed a genome-wide association study (GWAS) on a population of Finnish origin that included 247 infants with SPTB (gestational age [GA] < 36 weeks) and 419 term controls (GA 38-41 weeks). The strongest signal came within the gene encoding slit guidance ligand 2 (SLIT2; rs116461311, minor allele frequency 0.05, p = 1.6×10-6). Pathway analysis revealed the top-ranking pathway was axon guidance, which includes SLIT2. In 172 very preterm-born infants (GA <32 weeks), rs116461311 was clearly overrepresented (odds ratio 4.06, p = 1.55×10-7). SLIT2 variants were associated with SPTB in another European population that comprised 260 very preterm infants and 9,630 controls. To gain functional insight, we used immunohistochemistry to visualize SLIT2 and its receptor ROBO1 in placentas from spontaneous preterm and term births. Both SLIT2 and ROBO1 were located in villous and decidual trophoblasts of embryonic origin. Based on qRT-PCR, the mRNA levels of SLIT2 and ROBO1 were higher in the basal plate of SPTB placentas compared to those from term or elective preterm deliveries. In addition, in spontaneous term and preterm births, placental SLIT2 expression was correlated with variations in fetal growth. Knockdown of ROBO1 in trophoblast-derived HTR8/SVneo cells by siRNA indicated that it regulate expression of several pregnancy-specific beta-1-glycoprotein (PSG) genes and genes involved in inflammation. Our results show that the fetal SLIT2 variant and both SLIT2 and ROBO1 expression in placenta and trophoblast cells may be correlated with susceptibility to SPTB. SLIT2-ROBO1 signaling was linked with regulation of genes involved in inflammation, PSG genes, decidualization and fetal growth. We propose that this receptor-ligand couple is a component of the signaling network that promotes SPTB.

MicroRNA-Mediated Control of Inflammation and Tolerance in Pregnancy

Gestational age-dependent immune intolerance at the maternal-fetal interface might be a contributing factor to placental pathology and adverse pregnancy outcomes. Although the intrauterine setting is highly choreographed and considered to be a protective environment for the fetus, unscheduled inflammation might overwhelm the intrauterine milieu to cause a cascade of events leading to adverse pregnancy outcomes. The old paradigm of a sterile intrauterine microenvironment has been challenged, and altered microflora has been detected in gestational tissues and amniotic fluid in the absence of induction of significant inflammation. Is there a role for endotoxin tolerance at the maternal-fetal interface? Endotoxin tolerance is a phenomenon in which tissues or cells exposed to the bacterial product, particularly lipopolysaccharide, become less responsive to subsequent exposures accompanied by decreased expression of pro-inflammatory mediators. This could also be related to trained or experienced immunity that leads to the successful outcome of subsequent pregnancies. Adaptation to endotoxin tolerance or trained immunity might be critical in preventing rejection of the fetus by the maternal immune system and protecting the fetus from excessive maternal inflammatory responses to infectious agents; however, to date, the exact mechanisms contributing to the establishment and maintenance of tolerance at the maternal-fetal interface remain incompletely understood. There is now extensive evidence suggesting that microRNAs (miRNAs) play important roles in the maintenance of a healthy pregnancy. miRNAs not only circulate freely in extracellular fluids but are also packaged within extracellular vesicles (EVs) produced by various cells and tissues. The placenta is a known, abundant, and transient source of EVs; therefore, our proposed model suggests that repeated exposure to infectious agents induces a tolerant phenotype at the maternal-fetal interface mediated by specific miRNAs mostly contained within placental EVs. We hypothesize that impaired endotoxin tolerance or failed trained immunity at the maternal-fetal interface will result in a pathological inflammatory response contributing to early or late pregnancy maladies.

Complement Activation During Early Pregnancy and Clinical Predictors of Preterm Birth in African American Women

Complement activation is essential for select physiologic processes during pregnancy; however, excess activation has been associated with an increased risk for preterm birth (PTB). African American (AA) women experience disproportionately higher rates of inflammation-associated PTB than other groups of women; thus, the purpose of this study was to explore the relationship between complement activation and perinatal outcomes among AA women. A plasma sample was collected between 8 and 14 weeks' gestation from a cohort of healthy AA women (N = 144) enrolled in a larger PTB cohort study. Medical record review was conducted to collect information on clinical factors (cervical length, health behaviors, gestational age at delivery). Multiple regression analysis was used to explore the relationships between complement marker (C3a/Bb) concentrations and the outcomes of interest after adjusting for baseline characteristics. C3a/Bb concentrations were not significant predictors of the gestational age at delivery, cervical length, or behavioral risk factors for PTB in this sample. Complement markers may not influence pregnancy outcomes among AA women in the same way as in predominantly white populations; however, more studies are needed to define complement dysregulation and the relationship with outcomes among AA women.

Block of Granulocyte-Macrophage Colony-Stimulating Factor Prevents Inflammation-Induced Preterm Birth in a Mouse Model for Parturition

OBJECTIVE

A multitude of factors promotes inflammation in the reproductive tract leading to preterm birth. Macrophages peak in the cervix prior to birth and their numbers are increased by the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF). We hypothesize GM-CSF is produced from multiple sites in the genital tract and is a key mediator in preterm birth.

STUDY DESIGN

Ectocervical, endocervical, and amniotic fluid mesenchymal stem cells were treated with lipopolysaccharide (LPS), and the concentration and expression of GM-CSF was measured. Pregnant CD-1 mice on gestational day 17 received LPS and an intravenous injection of either anti-mouse GM-CSF or control antibody. After 6 hours, the preterm birth rate was recorded.

RESULTS

Treatment with LPS increased the GM-CSF concentration and messenger RNA expression after 24 hours in all 3 cell lines ( P < .01). Mice treated with LPS and the GM-CSF antibody had a preterm birth rate of 25%, compared to a 66.7% preterm birth rate in controls, within 6 hours ( P < .05, χ²). Treatment with the anti-mouse GM-CSF antibody decreased the concentration of GM-CSF in the mouse serum ( P < .01) but did not alter the number of macrophages or collagen content in the cervix.

CONCLUSION

These studies demonstrate that GM-CSF is produced from multiple sites in the genital tract and that treatment with an antibody to GM-CSF prevents preterm birth. Curiously, the anti-mouse GM-CSF antibody did not decrease the number of macrophages in the cervix. Further research is needed to determine whether antibodies to GM-CSF can be utilized as a therapeutic agent to prevent preterm birth.

Intestinal Barrier Dysfunction and Microbial Translocation in Human Immunodeficiency Virus-Infected Pregnant Women Are Associated With Preterm Birth

Background

Preterm birth (PTB) rates are high in human immunodeficiency virus (HIV)-infected populations, even when on treatment. Still, only a subset of all births in HIV-infected pregnant women result in PTB, suggesting that risk factors other than HIV infection itself are also important. Inflammation is a known risk factor in uninfected populations, but its role in HIV-infected population have not been studied; in addition, the immune pathways involved are not clear and noninvasive immune markers with predictive value are lacking. Our objective was to determine the association of select markers of inflammation with PTB in HIV-1-infected pregnant women.

Methods

Within a randomized trial of pregnant women receiving nevirapine (Six-Week Extended-Dose Nevirapine [SWEN] trial), we nested a case-control study (n = 107; 26 cases, 81 controls) to determine the association of maternal inflammation with PTB. Cases were defined as PTB (<37 weeks' gestational age). We assessed inflammation by measuring plasma levels of markers of general inflammation (C-reactive protein [CRP]), intestinal barrier dysfunction (intestinal fatty acid binding protein [I-FABP]), and microbial translocation/monocyte activation (soluble CD14 [sCD14] and CD163 [sCD163]). Multivariable logistic regression was used to determine the odds of PTB per log2 increase of each marker.

Results

In multivariable models, there was increased odds of PTB per unit increase of log2 sCD14 (adjusted odds ratio [aOR], 2.45; 95% confidence interval [CI], 1.24-4.86), log2 sCD163 (aOR, 3.87; 95% CI, 1.43-10.49), and log2 I-FABP (aOR, 2.28; 95% CI, 1.18-4.41) but not log2 CRP (aOR, 0.72; 95% CI, .48-1.09).

Conclusions

Our results show that select immune markers can identify women at higher risk for PTB in HIV-1-infected populations and suggest that modulating gut barrier integrity and microbial translocation may affect PTB.

Clinical Trials Registration

NCT00061321.

Evidence of a gene-environment interaction of NODAL variants and inflammation in preterm birth

OBJECTIVE

NODAL has been implicated in timing of parturition and immune regulation. We investigated the relationship between NODAL polymorphisms, infection/inflammation, and preterm birth.

STUDY DESIGN

For this secondary analysis, 613 women (189 preterm and 424 term) from the Montreal Prematurity Study were genotyped for NODAL polymorphisms and assessed for bacterial vaginosis and placental inflammation.

RESULT

NODAL polymorphisms were not associated with preterm birth. However, the rs2231947(C>T) variant allele was associated with increased risk for preterm birth among women with bacterial vaginosis (odds ratio: 2.76, 95% confidence interval: 1.12-6.85). Among women without placental inflammation, the rs1904589(A>G) variant allele was associated with increased risk of preterm birth (odds ratio: 1.31, 95% confidence interval: 1.02-1.70). Among women with placental inflammation, the rs10999338(C>T) variant allele was associated with reduced risk of preterm birth (odds ratio: 0.50, 95% confidence interval: 0.29-0.87).

CONCLUSION

The effect of NODAL polymorphisms on preterm birth depends on maternal infection/inflammation status.

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.

Intrauterine Inflammation, Epigenetics, and Microbiome Influences on Preterm Infant Health

PURPOSE OF REVIEW

Significant research reveals that the microbiome modulates perinatal and postnatal health. This review aims to examine mechanisms by which intrauterine infection, the epigenome, and microbiome specifically influence preterm infant health outcomes.

RECENT FINDINGS

Intrauterine infection is a primary cause of preterm birth and can cause alterations in gene expression and epigenetic programming as well as postnatal inflammatory responses in the offspring. Insights from our own studies demonstrate epigenetic modifications of TLRs associated with exposure to intrauterine inflammation, as well as a cross talk between host epigenome and microbiome. Lastly, the gut microbiome modulates maturation of inflammatory pathways, which influences the development of preterm infants.

SUMMARY

We present a unifying theme that preterm infant outcomes are associated with modulation of host immune and inflammatory responses, which are influenced by acute intrauterine infection, epigenetic, and microbiome factors.

Immunological Tolerance, Pregnancy, and Preeclampsia: The Roles of Semen Microbes and the Father

Although it is widely considered, in many cases, to involve two separable stages (poor placentation followed by oxidative stress/inflammation), the precise originating causes of preeclampsia (PE) remain elusive. We have previously brought together some of the considerable evidence that a (dormant) microbial component is commonly a significant part of its etiology. However, apart from recognizing, consistent with this view, that the many inflammatory markers of PE are also increased in infection, we had little to say about immunity, whether innate or adaptive. In addition, we focused on the gut, oral and female urinary tract microbiomes as the main sources of the infection. We here marshall further evidence for an infectious component in PE, focusing on the immunological tolerance characteristic of pregnancy, and the well-established fact that increased exposure to the father's semen assists this immunological tolerance. As well as these benefits, however, semen is not sterile, microbial tolerance mechanisms may exist, and we also review the evidence that semen may be responsible for inoculating the developing conceptus (and maybe the placenta) with microbes, not all of which are benign. It is suggested that when they are not, this may be a significant cause of PE. A variety of epidemiological and other evidence is entirely consistent with this, not least correlations between semen infection, infertility and PE. Our view also leads to a series of other, testable predictions. Overall, we argue for a significant paternal role in the development of PE through microbial infection of the mother via insemination.

First Trimester Vaginal Ureaplasma Biovar Colonization and Preterm Birth: Results of a Prospective Multicenter Study

BACKGROUND

While there is a proven association of upper genital tract Ureaplasma infection during pregnancy with adverse pregnancy outcome, the effect of vaginal Ureaplasma colonization on preterm delivery has been controversially debated.

OBJECTIVES

We hypothesized that women with isolation of vaginal U. parvum but not U. urealyticum are at increased risk for spontaneous preterm birth (SPB) compared to women with negative results.

METHODS

A vaginal swab taken between 12 and 14 weeks of gestation was analyzed for the presence of Ureaplasma biovars by PCR in 4,330 pregnant women.

RESULTS

Of the study cohort, 37% were positive for U. parvum, 5.9% for U. urealyticum, and 3.1% for both. The rates of SPB were 10.4% (OR 1.7, 95% CI 1.3, 2.2, p < 0.001) and 8.9% (OR 1.4, 95% CI 0.9, 2.3, p = 0.193) in the groups with isolation of U. parvum and U. urealyticum, respectively, compared to 6.4% in the group with negative PCR results. Multiple logistic regression and interaction analyses showed that vaginal colonization with U. parvum but not U. urealyticum was a statistically significant risk factor for SPB (adjusted OR 1.6, 95% CI 1.2, 2.1, p < 0.001), independent of other risk factors such as bacterial vaginosis and history of SPB.

CONCLUSION

Our study demonstrates a statistically significant and independent association between first-trimester vaginal colonization with U. parvum and subsequent SPB.

Maternal administration of melatonin exerts short- and long-term neuroprotective effects on the offspring from lipopolysaccharide-treated mice

Preterm birth is a major contributor to early and delayed physical and cognitive impairment. Epidemiological and experimental data indicate that maternal infections are a significant and preventable cause of preterm birth. Recently, melatonin has been suggested to exert neuroprotective effects in several models of brain injury. Here, we sought to investigate whether the administration of melatonin is able to prevent lipopolysaccharide (LPS)-induced fetal brain damage in a model of LPS-induced preterm labor. For this purpose, 15-day pregnant BALB/c mice received intraperitoneally 2 doses of LPS or vehicle: the first one at 10:00 hours (0.26 mg/kg) and the second at 13:00 hours (0.52 mg/kg). On day 14 of pregnancy, a group of mice was subcutaneously implanted with a pellet of 25 mg melatonin. This experimental protocol resulted in 100% of preterm birth and pup death in the LPS group and a 50% of term birth and pup survival in the melatonin + LPS group. In the absence of melatonin, fetuses from LPS-treated mothers showed histological signs of brain damage, microglial/macrophage activation, and higher levels of IL-1β, inducible nitric oxide synthase (NOS), and neuronal NOS mRNAs as well as increased histone acetyltransferase activity and histone H3 hyperacetylation. In contrast, antenatal administration of melatonin prevented LPS-induced fetal brain damage. Moreover, when behavioral traits were analyzed in the offspring from control, melatonin, and melatonin + LPS, no significant differences were found, suggesting that melatonin prevented LPS-induced long-term neurodevelopmental impairments. Collectively, our results suggest that melatonin could be a new therapeutic tool to prevent fetal brain damage and its long-term consequences induced by maternal inflammation.