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

The vaginal immunoproteome for the prediction of spontaneous preterm birth: A retrospective longitudinal study

Background

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Most cases of preterm birth occur spontaneously and result from preterm labor with intact (spontaneous preterm labor [sPTL]) or ruptured (preterm prelabor rupture of membranes [PPROM]) membranes. The prediction of spontaneous preterm birth (sPTB) remains underpowered due to its syndromic nature and the dearth of independent analyses of the vaginal host immune response. Thus, we conducted the largest longitudinal investigation targeting vaginal immune mediators, referred to herein as the immunoproteome, in a population at high risk for sPTB.

Methods

Vaginal swabs were collected across gestation from pregnant women who ultimately underwent term birth, sPTL, or PPROM. Cytokines, chemokines, growth factors, and antimicrobial peptides in the samples were quantified via specific and sensitive immunoassays. Predictive models were constructed from immune mediator concentrations.

Results

Throughout uncomplicated gestation, the vaginal immunoproteome harbors a cytokine network with a homeostatic profile. Yet, the vaginal immunoproteome is skewed toward a pro-inflammatory state in pregnant women who ultimately experience sPTL and PPROM. Such an inflammatory profile includes increased monocyte chemoattractants, cytokines indicative of macrophage and T-cell activation, and reduced antimicrobial proteins/peptides. The vaginal immunoproteome has improved predictive value over maternal characteristics alone for identifying women at risk for early (<34 weeks) sPTB.

Conclusions

The vaginal immunoproteome undergoes homeostatic changes throughout gestation and deviations from this shift are associated with sPTB. Furthermore, the vaginal immunoproteome can be leveraged as a potential biomarker for early sPTB, a subset of sPTB associated with extremely adverse neonatal outcomes.

Funding

This research was conducted by the Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS) under contract HHSN275201300006C. ALT, KRT, and NGL were supported by the Wayne State University Perinatal Initiative in Maternal, Perinatal and Child Health.

Effect of strontium on transcription factors identified by transcriptome analyses of bovine ruminal epithelial cells

BACKGROUND

Strontium (Sr) has similar physicochemical properties as calcium (Ca) and is often used to evaluate the absorption of this mineral. Because the major route of Ca absorption in the bovine occurs in the rumen, it is essential to understand whether Sr impacts the ruminal epithelial cells and to what extent.

RESULTS

In the present study, RNA sequencing and assembled transcriptome assembly were used to identify transcription factors (TFs), screening and bioinformatics analysis in bovine ruminal epithelial cells treated with Sr. A total of 1405 TFs were identified and classified into 64 families based on an alignment of conserved domains. A total of 174 differently expressed TFs (DE-TFs) were increased and 52 DE-TFs were decreased; the biological process-epithelial cell differentiation was inhibited according to the GSEA-GO analysis of TFs; The GO analysis of DE-TFs was enriched in the DNA binding. Protein-protein interaction network (PPI) found 12 hubs, including SMAD4, SMAD2, SMAD3, SP1, GATA2, NR3C1, PPARG, FOXO1, MEF2A, NCOA2, LEF1, and ETS1, which verified genes expression levels by real-time PCR.

CONCLUSIONS

In this study, SMAD2, PPARG, LEF1, ETS1, GATA2, MEF2A, and NCOA2 are potential candidates that could be targeted by Sr to mediate cell proliferation and differentiation, as well as lipid metabolism. Hence, these results enhance the comprehension of Sr in the regulation of transcription factors and provide new insight into the study of Sr biological function in ruminant animals.

Association between light rare earth elements in maternal plasma and the risk of spontaneous preterm birth: a nested case-control study from the Beijing birth cohort study

BACKGROUND

Parental exposure to rare earth elements (REEs) could increase the risk of premature rupture of membranes, a major cause of spontaneous preterm birth (SPB). In addition, different subtypes of SPB, such as spontaneous preterm labor (SPL) and preterm premature rupture of membranes (PPROM), may have different susceptibility to environmental exposure. Therefore, we investigated the potential associations between REE exposure in different trimesters and SPB and its subtypes.

METHODS

A nested case-control study was performed. We included 244 women with SPB as cases and 244 women with full-term delivery as controls. The plasma concentrations of light REEs were measured in the first and third trimesters. Logistic regression was used to analyze the associations between single REE levels and SPB, and Bayesian kernel machine regression (BKMR) was used to analyze the mixed-exposure effect.

RESULTS

Exposure to light REEs was associated with SPB and its subtypes only in the third trimester. Specifically, the intermediate- and highest-tertile concentration groups of La and the highest-tertile concentration group of Sm were associated with an increased risk of SPL, with adjusted odds ratios (AORs) of 2.00 (95% CIs: 1.07-3.75), 1.87 (95% CIs: 1.01-3.44), and 1.82 (95% CIs: 1.00-3.30), respectively. The highest-tertile concentration group of Pr was associated with an increased risk of PPROM, with an AOR of 1.69 (95% CIs: 1.00-2.85). Similar results were also found in BKMR models.

CONCLUSIONS

La and Sm levels in plasma may be associated with the risk of SPL, and Pr levels in plasma may be associated with the risk of PPROM.

Investigating the regenerative effects of folic acid on human amniotic epithelial stem cells and amniotic pore culture technique (APCT) model in vitro using an integrated pharmacological-bioinformatic approach

INTRODUCTION

Disruption of fetal membranes before the onset of labor is referred to as premature rupture of membranes (PROM). Lack of maternal folic acid (FA) supplementation reportedly leads to PROM. However, there is a lack of information on the location of FA receptors in the amniotic tissue. Additionally, the regulatory role and potential molecular targets of FA in PROM in vitro have rarely been investigated.

METHODS

The three FA receptors (folate receptor α isoform [FRα], transporter of reduced folate [RFC], and proton-coupled folate transporter [PCFT]) in human amniotic epithelial stem cells (hAESCs) and amniotic tissue were localized using immunohistochemistry and immunocytochemistry staining. Effect and mechanism analyses of FA were performed in hAESCs and amniotic pore culture technique (APCT) models. An integrated pharmacological-bioinformatics approach was utilized to explore the potential targets of FA for the treatment of PROM.

RESULTS

The three FA receptors were widely expressed in human amniotic tissue, especially in the hAESC cytoplasm. FA stimulated the amnion regeneration in the in vitro APCT model. This mimics the PROM status, in which cystathionine-β-synthase, an FA metabolite enzyme, may play an important role. The top ten hub targets (STAT1, mTOR, PIK3R1, PTPN11, PDGFRB, ABL1, CXCR4, NFKB1, HDAC1, and HDAC2) of FA for preventing PROM were identified using an integrated pharmacological-bioinformatic approach.

DISCUSSION

FRα, RFC, and PCFT are widely expressed in human amniotic tissue and hAESCs. FA aids the healing of ruptured membrane.

Proteomic analysis of plasma to identify novel biomarkers for intra-amniotic infection and/or inflammation in preterm premature rupture of membranes

To identify potential plasma biomarkers associated with microbial invasion of the amniotic cavity (MIAC) and/or intraamniotic inflammation (IAI) in women with preterm premature rupture of membranes (PPROM). This retrospective cohort study included 182 singleton pregnant women with PPROM (23-33 weeks) who underwent amniocentesis. Plasma samples; all subjects were chosen from these participants and were analyzed using label-free liquid chromatography-tandem mass spectrometry for proteome profiling using a nested case-control study design (cases with MIAC/IAI vs. non-MIAC/IAI controls [n = 9 each]). Three identified target molecules for MIAC/IAI were further verified by ELISA in the study cohort (n = 182). Shotgun proteomic analysis revealed 17 differentially expressed proteins (P < 0.05) in the plasma of MIAC/IAI cases. In particular, the levels of FCGR3A and haptoglobin, but not LRP1, were found to be increased in the plasma of patients with MIAC, IAI, and both MIAC/IAI compared with those without these conditions. Moreover, these differences remained significant after adjusting for gestational age at sampling. The area under the curves of plasma FCGR3A and haptoglobin ranged within 0.59-0.65 with respect to each of the three outcome measures. Plasma FCGR3A and haptoglobin were identified as potential independent biomarkers for less-invasively detecting MIAC/IAI in women with PPROM.

First-trimester prediction of preterm prelabour rupture of membranes incorporating cervical length measurement

OBJECTIVES

To examine early pregnancy risk factors for preterm prelabour rupture of membranes (PPROM) and develop a predictive model.

STUDY DESIGN

Retrospective analysis of a cohort of mixed-risk singleton pregnancies screened in the first and second trimesters in three Danish tertiary fetal medicine centres, including a cervical length measurement at 11-14 weeks, at 19-21 weeks and at 23-24 weeks of gestation. Univariable and multivariable logistic regression analyses were employed to identify predictive maternal characteristics, biochemical and sonographic factors. Receiver operating characteristic (ROC) curve analysis was used to determine predictors for the most accurate model.

RESULTS

Of 3477 screened women, 77 (2.2%) had PPROM. Maternal factors predictive of PPROM in univariable analysis were nulliparity (OR 2.0 (95% CI 1.2-3.3)), PAPP-A < 0.5 MoM (OR 2.6 (1.1-6.2)), previous preterm birth (OR 4.2 (1.9-8.9)), previous cervical conization (OR 3.6 (2.0-6.4)) and cervical length ≤ 25 mm on transvaginal imaging (first-trimester OR 15.9 (4.3-59.3)). These factors all remained statistically significant in a multivariable adjusted model with an AUC of 0.72 in the most discriminatory first-trimester model. The detection rate using this model would be approximately 30% at a false-positive rate of 10%. Potential predictors such as bleeding in early pregnancy and pre-existing diabetes mellitus affected very few cases and could not be formally assessed.

CONCLUSIONS

Several maternal characteristics, placental biochemical and sonographic features are predictive of PPROM with moderate discrimination. Larger numbers are required to validate this algorithm and additional biomarkers, not currently used for first-trimester screening, may improve model performance.

Perinatal, metabolic, and reproductive features in PPARG-related lipodystrophy

OBJECTIVE

The adipogenic PPARG-encoded PPARγ nuclear receptor also displays essential placental functions. We evaluated the metabolic, reproductive, and perinatal features of patients with PPARG-related lipodystrophy.

METHODS

Current and retrospective data were collected in patients referred to a National Rare Diseases Reference Centre.

RESULTS

26 patients from 15 unrelated families were studied (18 women, median age 43 years). They carried monoallelic PPARG variants except a homozygous patient with congenital generalized lipodystrophy. Among heterozygous patients aged 16 or more (n = 24), 92% had diabetes, 96% partial lipodystrophy (median age at diagnosis 24 and 37 years), 78% hypertriglyceridaemia, 71% liver steatosis, and 58% hypertension. The mean BMI was 26 ± 5.0 kg/m2. Women (n = 16) were frequently affected by acute pancreatitis (n = 6) and/or polycystic ovary syndrome (n = 12). Eleven women obtained one or several pregnancies, all complicated by diabetes (n = 8), hypertension (n = 4), and/or hypertriglyceridaemia (n = 10). We analysed perinatal data of patients according to the presence (n = 8) or absence (n = 9) of a maternal dysmetabolic environment. The median gestational age at birth was low in both groups (37 and 36 weeks of amenorrhea, respectively). As expected, the birth weight was higher in patients exposed to a foetal dysmetabolic environment of maternal origin. In contrast, 85.7% of non-exposed patients, in whom the variant is, or is very likely to be, paternally-inherited, were small for gestational age.

CONCLUSIONS

Lipodystrophy-related PPARG variants induce early metabolic complications. Our results suggest that placental expression of PPARG pathogenic variants carried by affected foetuses could impair prenatal growth and parturition. This justifies careful pregnancy monitoring in affected families.

Association of single and multiple prefluoroalkyl substances exposure with preterm birth: Results from a Chinese birth cohort study

BACKGROUND

Perfluoroalkyl substances (PFASs) are persistent organic pollutants that may lead the adverse birth outcomes, including preterm birth (PTB). However, previous studies have reported inconsistent results on the association between PFASs and PTB, and lack of the epidemiological evidence regarding the effect of PFASs mixture on PTB. This study aimed to explore association of individual and multiple exposure to PFASs with PTB.

METHODS

The study subjects were consisted of 1341 pregnant women from Guangxi Zhuang Birth Cohort in Guangxi, China, from June 2015 to April 2019. Nine PFASs concentrations in the maternal serum were examined by ultrahigh liquid performance chromatography-tandem mass spectrometry, and the gestational weeks were obtained from medical records. We applied binary logistics regression model to explore correlation between individual PFAS and PTB and inspected the combined effect of PFASs mixture on PTB by applying Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) regression models.

RESULTS

In adjusted logistics regression model, perfluorooctane sulfonate (PFOS), perfluoroheptanoic acid (PFHpA), perfluorobutanesulfonic acid (PFBS), ∑perfluorinated sulfonic acids (PFSA), and ∑PFASs were positively associated with the risk of PTB. In contrast, perfluoroundecanoic acid (PFUnA), perfluorohexane sulfonate (PFHxS), and perfluorooctanoic acid (PFOA) were negatively associated with the risk of PTB. These associations of n PFOS and PFHpA with PTB were found to be more pronounced in male infants. Restricted cubic splines (RCSs) showed an inverse U-shaped relationship between PFBS and PTB. Analysis from BKMR model showed a positive association between PFASs mixture and PTB, and no evidence of interactions among the nine PFASs were detected. Additionally, PFHpA, PFOS, and PFBS were identified as the main contributors for the effect of PFASs mixture on increasing the risk of PTB by BKMR and WQS models.

CONCLUSION

Prenatal exposure to higher levels of PFASs mixture was associated with higher risk of PTB.

Genetics, epigenetics, and transcriptomics of preterm birth

Preterm birth contributes significantly to neonatal mortality and morbidity. Despite its global significance, there has only been limited progress in preventing preterm birth. Spontaneous preterm birth (sPTB) results from a wide variety of pathological processes. Although many non-genetic risk factors influence the timing of gestation and labor, compelling evidence supports the role of substantial genetic and epigenetic influences and their interactions with the environment contributing to sPTB. To investigate a common and complex disease such as sPTB, various approaches such as genome-wide association studies, whole-exome sequencing, transcriptomics, and integrative approaches combining these with other 'omics studies have been used. However, many of these studies were typically small or focused on a single ethnicity or geographic region with limited data, particularly in populations at high risk for sPTB, or lacked a robust replication. These studies found many genes involved in the inflammation and immunity-related pathways that may affect sPTB. Recent studies also suggest the role of epigenetic modifications of gene expression by the environmental signals as a potential contributor to the risk of sPTB. Future genetic studies of sPTB should continue to consider the contributions of both maternal and fetal genomes as well as their interaction with the environment.

Nitric oxide-related gene and microRNA expression in peripheral blood in pregnancy vary by self-reported race

Adverse pregnancy outcomes disproportionately affect non-Hispanic (NH) Black patients in the United States. Structural racism has been associated with increased psychosocial distress and inflammation and may trigger oxidative stress. Thus, the nitric oxide (NO) pathway (involved in the regulation of inflammation and oxidative stress) may partly explain the underlying disparities in obstetric outcomes.Cohort study of 154 pregnant patients with high-risk obstetric histories; n = 212 mRNAs and n = 108 microRNAs (miRNAs) in the NO pathway were evaluated in circulating white blood cells. NO pathway mRNA and miRNA transcript counts were compared by self-reported race; NH Black patients were compared with women of other races/ethnicities. Finally, miRNA-mRNA expression levels were correlated.Twenty-two genes (q < 0.10) were differentially expressed in self-identified NH Black individuals. Superoxide dismutase 1 (SOD1), interleukin-8 (IL-8), dynein light chain LC8-type 1 (DYNLL1), glutathione peroxidase 4 (GPX4), and glutathione peroxidase 1 (GPX1) were the five most differentially expressed genes among NH Black patients compared to other patients. There were 63 significantly correlated miRNA-mRNA pairs (q < 0.10) demonstrating potential miRNA regulation of associated target mRNA expression. Ten miRNAs that were identified as members of significant miRNA-mRNA pairs were also differentially expressed among NH Black patients (q < 0.10).These findings support an association between NO pathway and inflammation and infection-related mRNA and miRNA expression in blood drawn during pregnancy and patient race/ethnicity. These findings may reflect key differences in the biology of inflammatory gene dysregulation that occurs in response to the stress of systemic racism and that underlies disparities in pregnancy outcomes.

Stillbirth in COVID-19 Affected Pregnancies: A Double Whammy for the Mother

Introduction

Pregnant women represent a high-risk group especially during the COVID-19 pandemic, suffering at the expense of pandemic restrictions and landing up in adverse maternofetal outcomes including stillbirth. Fetal demise along with COVID-19 disease acts as a double blow to these mothers. Literature is still limited on its impact on maternofetal outcomes.

Methods

A prospective, observational study was conducted in a tertiary care hospital in Delhi, India from April 15, 2020 to April 14, 2021, wherein all pregnant mothers with SARS-CoV-2 infection in the hospital who delivered a stillborn baby were enrolled and analyzed for incidence of stillbirth. These women were evaluated for risk factors and causes for stillbirth.

Results

Out of 15859 deliveries in the institute, there were 330 viable births among COVID-19 affected pregnancies. The incidence of stillbirth was 7.2% (24/330). The institutional delivery rate fell by 43% during the pandemic. The majority of cases were unbooked, from rural areas and of low socioeconomic status (p<0.01). The most significant risk factor and cause for stillbirth was an associated comorbidity (75%, p<0.001), notably severe forms of hypertensive disorders of pregnancy (HDP, 41.6%, p=0.002), followed by preterm labour (58.3%) and preterm premature rupture of membranes (PPROM, 29.1%, p<0.001). HDP remained the main cause of macerated stillbirths while maternal fever (50%, p<0.001) was the main cause of fresh stillbirth. Major modifiable factors were lack of awareness of when to seek care (83.3%), financial reasons (75%), commutation problems (87.5%), distance to hospitals (50%) and delayed referral (41.6%).

Conclusion

Improved policy-making, with an emphasis on telemedicine, COVID-19 preparedness alongside amped up vaccination and healthcare workers training will help reduce adverse maternofetal outcomes.

Genome and transcriptome profiling of spontaneous preterm birth phenotypes

Preterm birth (PTB) occurs before 37 weeks of gestation. Risk factors include genetics and infection/inflammation. Different mechanisms have been reported for spontaneous preterm birth (SPTB) and preterm birth following preterm premature rupture of membranes (PPROM). This study aimed to identify early pregnancy biomarkers of SPTB and PPROM from the maternal genome and transcriptome. Pregnant women were recruited at the Liverpool Women’s Hospital. Pregnancy outcomes were categorised as SPTB, PPROM (≤ 34 weeks gestation, n = 53), high-risk term (HTERM, ≥ 37 weeks, n = 126) or low-risk (no history of SPTB/PPROM) term (LTERM, ≥ 39 weeks, n = 188). Blood samples were collected at 16 and 20 weeks gestation from which, genome (UK Biobank Axiom array) and transcriptome (Clariom D Human assay) data were acquired. PLINK and R were used to perform genetic association and differential expression analyses and expression quantitative trait loci (eQTL) mapping. Several significant molecular signatures were identified across the analyses in preterm cases. Genome-wide significant SNP rs14675645 (ASTN1) was associated with SPTB whereas microRNA-142 transcript and PPARG1-FOXP3 gene set were associated with PPROM at week 20 of gestation and is related to inflammation and immune response. This study has determined genomic and transcriptomic candidate biomarkers of SPTB and PPROM that require validation in diverse populations.

IL-27 Mediates Th1 Cells Infiltration in Fetal Membranes in Preterm Labor

The objective of this study is to investigate the effect of IL-27 on Th1 cells infiltration in human fetal membranes (FMs) in preterm labor (PL). The expression of Th1 cells specific transcription factor (T-bet), Th1 cells infiltration related molecules (CXCL9, CXCL10, CXCL11, and ICAM-1), and IL-27 receptor α subunit (IL-27Rα) was compared in human FMs from pregnant women in PL group and term labor (TL) group. In vitro, rhIL-27 was added to the culture medium of amniotic epithelial cells (WISH cells) to detect the expression of CXCL9, CXCL10, CXCL11, and ICAM-1. Furthermore, the underlying signaling pathway was detected by single-sample gene set enrichment analysis and western blot analysis. The expression of T-bet and CXCL9, CXCL10, CXCL11, and ICAM-1 as well as IL-27Rα was higher in human FMs from PL group than TL group. In vitro, rhIL-27 could upregulate the expression of CXCL9, CXCL10, CXCL11, and ICAM-1 in WISH cells. Using gene-set enrichment analysis of FMs, JAK/STAT signaling pathway was found to be activated by IL-27 signaling in PL. Using western blot analysis, JAK2/STAT1/STAT3 signaling pathway was confirmed to be enhanced in rhIL-27 treated WISH cells. In addition, AG490 (JAK2 inhibitor) could inhibit the secretion of CXCL9, CXCL10, and CXCL11 in WISH cells stimulated by rhIL-27. Our results suggested that IL-27 may promote Th1 cells infiltration in human FMs in PL, by promoting the expression of CXCL9, CXCL10, and CXCL11 at least partly through JAK2/STAT1/STAT3 signaling pathway.

The Role of IL-27 in the Systemic Inflammatory Response That Accompanies Preterm Labour

This study aimed to investigate whether interleukin-27 (IL-27) activates maternal peripheral blood mononuclear cells (PBMCs) and induces inflammatory responses in amniotic epithelial cells in preterm labour (PL). The expression of IL-27p28, EBI3 and IL-27Rα was compared in maternal PBMCs of the PL, term labour (TL) and term not in labour (TNL) groups. The relationship between IL-27 and molecules associated with PBMC activation was investigated using bioinformatic and quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses. We investigated the inflammatory effects of IL-27 in PBMCs and its underlying mechanisms in vitro. In addition, we treated amniotic epithelial cells (WISH cells) with a PBMC-conditioned medium to identify the inflammatory effects of IL-27-treated PBMCs in amniotic epithelial cells. The expression of IL-27p28 and IL-27Rα in PBMCs of the PL group was higher than that in the TL/TNL groups. Bioinformatic analysis revealed that IL-27 was positively correlated with IFNG, IL6, IL1β, CXCL10 and ICAM1 in the whole blood samples of pregnant women in the PL group, which was confirmed using qRT-PCR. Furthermore, rhIL-27 promoted the expression of Th1 cell-related molecules (T-bet, IFN-γ and ICAM-1) and proinflammatory cytokines (IL-6 and IL-1β) in PBMCs in vitro, which was partially mediated by the JAK2/STAT1 pathway. In addition, it enhanced the expression of IL-27p28, EBI3 and IL-27Rα in PBMCs. Moreover, the expression of IL-6, IL-1β and TNF-α in WISH cells was significantly increased by the conditional medium derived from IL-27-treated PBMCs. IL-27 upregulated the expression of Th1 cell-related molecules and proinflammatory cytokines in PBMCs partially mediated by the JAK2/STAT1 pathway. Inflammatory responses were induced in WISH cells by a conditional medium derived from IL-27-treated PBMCs. Therefore, IL-27 may contribute to PL by promoting inflammation in maternal PBMCs and amniotic epithelial cells.

Metabolic profiling of maternal serum of women at high-risk of spontaneous preterm birth using NMR and MGWAS approach

Preterm birth (PTB) is a leading global cause of infant mortality. Risk factors include genetics, lifestyle choices and infection. Understanding the mechanism of PTB could aid the development of novel approaches to prevent PTB. This study aimed to investigate the metabolic biomarkers of PTB in early pregnancy and the association of significant metabolites with participant genotypes. Maternal sera collected at 16 and 20 weeks of gestation, from women who previously experienced PTB (high-risk) and women who did not (low-risk controls), were analysed using 1H nuclear magnetic resonance (NMR) metabolomics and genome-wide screening microarray. ANOVA and probabilistic neural network (PNN) modelling were performed on the spectral bins. Metabolomics genome-wide association (MGWAS) of the spectral bins and genotype data from the same participants was applied to determine potential metabolite-gene pathways. Phenylalanine, acetate and lactate metabolite differences between PTB cases and controls were obtained by ANOVA and PNN showed strong prediction at week 20 (AUC = 0.89). MGWAS identified several metabolite bins with strong genetic associations. Cis-eQTL analysis highlighted TRAF1 (involved in the inflammatory pathway) local to a non-coding SNP associated with lactate at week 20 of gestation. MGWAS of a well-defined cohort of participants highlighted a lactate-TRAF1 relationship that could potentially contribute to PTB.

Preterm birth and genitourinary tract infections: assessing gene-environment interaction

BACKGROUND

Preterm birth (PTB) is the leading cause of perinatal morbimortality worldwide. Genetic and environmental factors could raise PTB risk. The aim of this study was to analyze the contribution of the statistical interaction between genes and vaginal-urinary tract infections (VI-UTI) to the risk of PTB by clinical subtype.

METHODS

Twenty-four SNPs were genotyped in 18 candidate genes from 352 fetal triads and 106 maternal triads. Statistical interactions were evaluated with conditional logistic regression models based on genotypic transmission/disequilibrium test.

RESULTS

In PTB-idiopathic subtype mothers exposed to UTI, fetal SNPs rs11686474 (FSHR), rs4458044 (CRHR1, allele G), rs883319 (KCNN3), and maternal SNP rs1882435 (COL4A3) showed a nominal significant increment in prematurity risk. In preterm premature rupture of membranes (PPROM), fetal SNP rs2277698 (TIMP2) showed a nominal significant risk increment. In mothers exposed to VI, fetal SNP rs5742612 (IGF1) in PTB-PPROM and maternal SNP rs4458044 (CRHR1, allele C) in spontaneous PTB showed nominal significant increment in prematurity risk.

CONCLUSIONS

Certain maternal and fetal genes linked to infectious/inflammatory and hormonal regulation processes increase prematurity risk according to clinical subtype when mothers are exposed to UTI or VI. These findings may help in the understanding of PTB etiology and PTB prevention.

IMPACT

Preterm birth is a major cause of perinatal morbimortality worldwide and its etiology remains unknown. This work provides evidence on the statistical interaction of six genes with gestational vaginal or urinary infections leading to the occurrence of preterm births. Statistical interactions vary according to infection type, genotype (maternal and fetal), and clinical subtype of prematurity. Certain maternal and fetal genetic variants of genes linked to infectious/inflammatory and hormonal regulation processes would increase the risk of prematurity according to clinical subtype and infection type. Our findings may help in the study of etiology of preterm birth and its prevention.

Current and Emerging Strategies for Prediction and Diagnosis of Prelabour Rupture of the Membranes: A Narrative Review

Prelabour rupture of membranes (PROM) refers to the disruption of foetal membranes before the onset of labour, resulting in the leakage of amniotic fluid. PROM complicates 3% and 8% of preterm and term pregnancies, respectively. Accurate and timely diagnosis is crucial for effective management to prevent adverse maternal- and foetal-outcomes. The diagnosis of equivocal PROM cases with traditional methods often becomes challenging in current obstetrics practice; therefore, various novel biochemical markers have emerged as promising diagnostic tools. This narrative review is sought to review the published data to understand the current and emerging trends in diagnostic modalities in term and preterm pregnancies complicated with PROM and the potential role of various markers for predicting preterm PROM (pPROM) and chorioamnionitis in women with pPROM.

Vaginal bacterial load in the second trimester is associated with early preterm birth recurrence: a nested case-control study

OBJECTIVE

To assess the association between vaginal microbiome (VMB) composition and recurrent early spontaneous preterm birth (sPTB)/preterm prelabour rupture of membranes (PPROM).

DESIGN

Nested case-control study.

SETTING

UK tertiary referral hospital.

SAMPLE

High-risk women with previous sPTB/PPROM <34⁺⁰  weeks' gestation who had a recurrence (n = 22) or delivered at ≥37⁺⁰  weeks without PPROM (n = 87).

METHODS

Vaginal swabs collected between 15 and 22 weeks' gestation were analysed by 16S rRNA gene sequencing and 16S quantitative PCR.

MAIN OUTCOME MEASURE

Recurrent early sPTB/PPROM.

RESULTS

Of the 109 high-risk women, 28 had anaerobic vaginal dysbiosis, with the remainder dominated by lactobacilli (Lactobacillus iners 36/109, Lactobacillus crispatus 23/109, or other 22/109). VMB type and diversity were not associated with recurrence. Women with a recurrence, compared to those without, had a higher median vaginal bacterial load (8.64 versus 7.89 log₁₀ cells/mcl, adjusted odds ratio [aOR] 1.90, 95% CI 1.01-3.56, P = 0.047) and estimated Lactobacillus concentration (8.59 versus 7.48 log₁₀ cells/mcl, aOR 2.35, (95% CI 1.20-4.61, P = 0.013). A higher recurrence risk was associated with higher median bacterial loads for each VMB type after stratification, although statistical significance was reached only for L. iners domination (aOR 3.44, 95% CI 1.06-11.15, P = 0.040). Women with anaerobic dysbiosis or L. iners domination had a higher median vaginal bacterial load than women with a VMB dominated by L. crispatus or other lactobacilli (8.54, 7.96, 7.63, and 7.53 log₁₀ cells/mcl, respectively).

CONCLUSIONS

Vaginal bacterial load is associated with early sPTB/PPROM recurrence. Domination by lactobacilli other than L. iners may protect women from developing high bacterial loads. Future PTB studies should quantify vaginal bacteria and yeasts.

TWEETABLE ABSTRACT

Increased vaginal bacterial load in the second trimester may be associated with recurrent early spontaneous preterm birth.

Spontaneous preterm birth: the underpinnings in the maternal and fetal genomes

Preterm birth (PTB) is a major cause of neonatal mortality and health complications in infants. Elucidation of its genetic underpinnings can lead to improved understanding of the biological mechanisms and boost the development of methods to predict PTB. Although recent genome-based studies of both mother and fetus have identified several genetic loci which might be implicated in PTB, these results suffer from a lack of consistency across multiple studies and populations. Moreover, results of functional validation of most of these findings are unavailable. Since medically indicated preterm deliveries have well-known heterogeneous causes, we have reviewed only those studies which investigated spontaneous preterm birth (sPTB) and have attempted to suggest probable biological mechanisms by which the implicated genetic factors might result in sPTB. We expect our review to provide a panoramic view of the genetics of sPTB.

TBX2, a Novel Regulator of Labour

Background and Objectives: Therapeutic interventions targeting molecular factors involved in the transition from uterine quiescence to overt labour are not substantially reducing the rate of spontaneous preterm labour. The identification of novel rational therapeutic targets are essential to prevent the most common cause of neonatal mortality. Based on our previous work showing that Tbx2 (T-Box transcription factor 2) is a putative upstream regulator preceding progesterone withdrawal in mouse myometrium, we now investigate the role of TBX2 in human myometrium. Materials and Methods: RNA microarray analysis of (A) preterm human myometrium samples and (B) myometrial cells overexpressing TBX2 in vitro, combined with subsequent analysis of the two publicly available datasets of (C) Chan et al. and (D) Sharp et al. The effect of TBX2 overexpression on cytokines/chemokines secreted to the myometrium cell culture medium were determined by Luminex assay. Results: Analysis shows that overexpression of TBX2 in myometrial cells results in downregulation of TNFα- and interferon signalling. This downregulation is consistent with the decreased expression of cytokines and chemokines of which a subset has been previously associated with the inflammatory pathways relevant for human labour. In contrast, CXCL5 (C-X-C motif chemokine ligand 5), CCL21 and IL-6 (Interleukin 6), previously reported in relation to parturition, do not seem to be under TBX2 control. The combined bioinformatical analysis of the four mRNA datasets identifies a subset of upstream regulators common to both preterm and term labour under control of TBX2. Surprisingly, TBX2 mRNA levels are increased in preterm contractile myometrium. Conclusions: We identified a subset of upstream regulators common to both preterm and term labour that are activated in labour and repressed by TBX2. The increased TBX2 mRNA expression in myometrium collected during a preterm caesarean section while in spontaneous preterm labour compared to tissue harvested during iatrogenic preterm delivery does not fit the bioinformatical model. We can only explain this by speculating that the in vivo activity of TBX2 in human myometrium depends not only on the TBX2 expression levels but also on levels of the accessory proteins necessary for TBX2 activity.

Obstetric and Perinatal Outcomes after Very Early Preterm Premature Rupture of Membranes (PPROM)-A Retrospective Analysis over the Period 2000-2020

Background and Objectives: Pre-term premature rupture of membranes (PPROM) responds for one third of preterm births, and it is associated with other complications that increase the risk of maternal or fetal poor outcome. To reduce uncertainty and provide accurate information to patients, the analysis of the large series is of great importance. In order to learn about the evolution over the time of the obstetric and perinatal outcomes in cases of PPROM at, or before, 28 weeks (very early PPROM) managed with an expectant/conservative protocol, we have designed the present study. Materials and Methods: We retrospectively studied all cases of very early PPROM attended in Malaga University Regional Hospital from 2000 to 2020. Results: Among 119,888 deliveries assisted, 592 cases of PPROM occurred in pregnancies at or before 28 weeks (0.49% of all deliveries, 3.9% of all preterm births and 12.9% of all cases of PPROM). The mean duration of the latency period between PPROM and delivery was 13.5 days (range 0 to 88 days), enlarging over the years. The mean gestational age at delivery was 27 weeks (SD 2.9; range 17–34). The proportion of cesarean deliveries was 52.5%. The overall perinatal mortality rate was 26.5%, decreasing over the period with a significant correlation Pearson’s coefficient −0.128 (p < 0.05). Conclusions: In the period 2000–2020, there was an improvement in the outcomes of very early PPROM cases and perinatal mortality showed a clear trend to decrease.

NF-κB and Its Regulators During Pregnancy

The transcriptional factor NF-κB is a nuclear factor involved in both physiological and pathological processes. This factor can control the transcription of more than 400 genes, including cytokines, chemokines, and their modulators, immune and non-immune receptors, proteins involved in antigen presentation and cell adhesion, acute phase and stress response proteins, regulators of apoptosis, growth factors, other transcription factors and their regulators, as well as different enzymes; all these molecules control several biological processes. NF-κB is a tightly regulated molecule that has also been related to apoptosis, cell proliferation, inflammation, and the control of innate and adaptive immune responses during onset of labor, in which it has a crucial role; thus, early activation of this factor may have an adverse effect, by inducing premature termination of pregnancy, with bad outcomes for the mother and the fetus, including product loss. Reviews compiling the different activities of NF-κB have been reported. However, an update regarding NF-κB regulation during pregnancy is lacking. In this work, we aimed to describe the state of the art around NF-κB activity, its regulatory role in pregnancy, and the effect of its dysregulation due to invasion by pathogens like Trichomonas vaginalis and Toxoplasma gondii as examples.

Novel Insights into the Regulatory Role of Nuclear Factor (Erythroid-Derived 2)-Like 2 in Oxidative Stress and Inflammation of Human Fetal Membranes

Fetal membrane dysfunction in response to oxidative stress (OS) is associated with adverse pregnancy outcomes. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is one of the regulators of innate OS response. This study evaluated changes in Nrf2 expression and its downstream targets heme oxygenase (HO-1) and peroxisome proliferator-activated receptor gamma (PPARγ) in fetal membranes during OS and infection in vitro. Furthermore, we tested the roles of sulforaphane (SFN; an extract from cruciferous vegetables) and trigonelline (TRN; an aromatic compound in coffee) in regulating Nrf2 and its targets. Fetal membranes (n = 6) collected at term were placed in an organ explant system were treated with water-soluble cigarette smoke extract (CSE), an OS inducer (1:10), and lipopolysaccharide (LPS; 100 ng/mL). Nrf2 expression, expression, its enhancement by sulforaphane (SFN, 10 µM/mL) and down regulation by TRN (10uM/mL) was determined by western blots. Expression of Nrf2 response elements PPARγ (western) heme oxygenase (HO-1), and IL-6 were quantified by ELISA. CSE and LPS treatment of fetal membranes increased nrf2, but reduced HO-1 and PPARγ and increased IL-6. Co-treatment of SFN, but not with TRN, with CSE and LPS increased Nrf2 substantially, as well as increased HO-1 and PPARγ and reduced IL-6 expression. Risk factor-induced Nrf2 increase is insufficient to generate an antioxidant response in fetal membranes. Sulforaphane may enhance innate antioxidant and anti-inflammatory capacity by increasing NRF-2 expression.

Differential Response of Gestational Tissues to TLR3 Viral Priming Prior to Exposure to Bacterial TLR2 and TLR2/6 Agonists

Background: Infection/inflammation is an important causal factor in spontaneous preterm birth (sPTB). Most mechanistic studies have concentrated on the role of bacteria, with limited focus on the role of viruses in sPTB. Murine studies support a potential multi-pathogen aetiology in which a double or sequential hit of both viral and bacterial pathogens leads to a higher risk preterm labour. This study aimed to determine the effect of viral priming on bacterial induced inflammation in human in vitro models of ascending and haematogenous infection.

Methods: Vaginal epithelial cells, and primary amnion epithelial cells and myocytes were used to represent cell targets of ascending infection while interactions between peripheral blood mononuclear cells (PBMCs) and placental explants were used to model systemic infection. To model the effect of viral priming upon the subsequent response to bacterial stimuli, each cell type was stimulated first with a TLR3 viral agonist, and then with either a TLR2 or TLR2/6 agonist, and responses compared to those of each agonist alone. Immunoblotting was used to detect cellular NF-κB, AP-1, and IRF-3 activation. Cellular TLR3, TLR2, and TLR6 mRNA was quantified by RT-qPCR. Immunoassays were used to measure supernatant cytokine, chemokine and PGE2 concentrations.

Results: TLR3 (“viral”) priming prior to TLR2/6 agonist (“bacterial”) exposure augmented the pro-inflammatory, pro-labour response in VECs, AECs, myocytes and PBMCs when compared to the effects of agonists alone. In contrast, enhanced anti-inflammatory cytokine production (IL-10) was observed in placental explants. Culturing placental explants in conditioned media derived from PBMCs primed with a TLR3 agonist enhanced TLR2/6 agonist stimulated production of IL-6 and IL-8, suggesting a differential response by the placenta to systemic inflammation compared to direct infection as a result of haematogenous spread. TLR3 agonism generally caused increased mRNA expression of TLR3 and TLR2 but not TLR6.

Conclusion: This study provides human in vitro evidence that viral infection may increase the susceptibility of women to bacterial-induced sPTB. Improved understanding of interactions between viral and bacterial components of the maternal microbiome and host immune response may offer new therapeutic options, such as antivirals for the prevention of PTB.

IκBNS and IL-6 expression is differentially established in the uterus of pregnant healthy and infected mice

During pregnancy, NF-κB plays an important role for embryo implantation and the onset of labor. Regulated IL-6 production, under transcriptional control of NF-κB, is essential for a successful pregnancy outcome and the atypical regulator IκBNS is involved in this process. Previously, we showed that IκBNS negatively regulates IL-6 in uterine tissues during mouse estrous cycle. In this work, we analyzed if IκBNS and IL-6 expression in pregnant mice under physiological or L. monocytogenes-infected conditions would remain as observed in estrous cycle. In the healthy pregnancy IL-6 was highly expressed during implantation/placentation and labor stages but decreased during fetal development and post-partum stages. In contrast, in mice infected before pregnancy, IL-6 expression was not increased in the implantation stage, and its regulator IκBNS increased more in the infected condition rather than in the healthy pregnancy. IκBNS expression was reduced in post-implantation infection, allowing for IL-6 overexpression. The IκBNS-unrelated cytokine IL-36γ, used as inflammatory cytokine marker, was severely increased in the infected uterine tissues. When we analyzed the effect of infection over the fetuses, we found that pre-implantation infection caused the resorption (rejection) of some products, while the post-implantation infection restricted the intrauterine growth of fetuses. The results suggest that in the uterine tissue of pregnant mice the regulatory effect of IκBNS over IL-6 is more evident in an infection status rather than in a healthy condition.

Protein Profile Changes in Circulating Placental Extracellular Vesicles in Term and Preterm Births: A Longitudinal Study

Spontaneous preterm birth (PTB) is a major obstetrical problem around the globe and the mechanisms leading to PTB are unclear. Recently, changes in the circulating levels of placental extracellular vesicles (EVs) during pregnancy have been associated with various pregnancy complications. However, progress in the field is hindered by the inability to isolate placental EVs from the maternal circulation. A longitudinal study design was used to determine the protein cargo present in circulating placental EVs in maternal plasma of term and PTB across gestation (ie, first, second, and third trimester). Placental-derived EVs were enriched from the total EV population based on their expression of membrane-bound placental alkaline phosphatase (PLAP). A quantitative, information-independent acquisition (sequential windowed acquisition of all theoretical mass spectra [SWATH]) approach identified and quantified the placental EV protein contents. PLAP+ EVs did not change in characteristics (size, shape, and markers) but did differ in numbers across gestation with low levels in PTB. A comparison analysis between the PLAP+ EV proteome from term and PTB revealed 96 proteins differing significantly (P < 0.05, false discovery rate 1%) across gestation. Bioinformatics analysis of differentially expressed proteins revealed consistent upregulation of inflammatory pathways in both upregulation of epithelial mesenchymal transition pathways at term and downregulation of coagulation/complement activation in preterm. Characterization of the proteomic profile in PLAP+ EVs across gestation demonstrates dramatic changes, which might be used to understand the biological process associated with early parturition and develop biomarkers for predicting high-risk status for PTB.

The PLART study: incidence of preterm labor and adverse pregnancy outcomes after assisted reproductive techniques-a retrospective cohort study

KEY MESSAGE

Even though assisted reproductive techniques represent one of the greatest achievements in modern medicine, the risk of preterm birth related to these pregnancies is about twice as high. This must be highlighted and further investigated to optimize the management of both mothers and newborns.

PURPOSE

The purpose of this study was to compare adverse pregnancy outcomes after assisted reproductive techniques (ART) and spontaneous conceptions, focusing on the incidence of preterm births (PTB) and distinguishing between iatrogenic and spontaneous events.

METHODS

This retrospective cohort study analyzed single births of one Italian hospital. The incidence of PTBs in ART pregnancies, divided into iatrogenic procedures, spontaneous preterm labors and preterm premature ruptures of the membranes (pPROMs), was compared with the non-ART control group. The incidence of other adverse pregnancy outcomes and the types of delivery were also reported and compared.

RESULTS

Of the 11,769 single births included, 2.39% were conceived by ART. The incidence of PTBs was 4.74% for spontaneous pregnancies and 12.8% for ART pregnancies (aOR 1.93; 95% CI 1.29-2.88). The percentage of iatrogenic procedures was 27.78% in the ART-PTBs' group and 30.88% in the non-ART-PTBs' controls. ART pregnancies showed an increased incidence of pPROMs (6.40% versus 2.41%), preterm labors (2.85% versus 0.93%), hypertensive disorders of the pregnancy (8.19% versus 2.32%), placenta previa (3.20% versus 0.59%), cesarean sections (28.47% versus 16.27%) and vacuum extractions (10.32% versus 5.19%).

CONCLUSIONS

Singleton ART pregnancies have a higher risk of PTB which is mostly linked to a higher incidence of pPROMs and spontaneous preterm labor. The concurrency of a demonstrated higher risk of hypertensive gestational disorders and placenta previa suggests that placental development plays an important role in the pathogenesis of PTB.

Predicting the likelihood of bronchopulmonary dysplasia in premature neonates

Introduction: Bronchopulmonary dysplasia (BPD) is the most common serious pulmonary morbidity in premature infants. Despite ongoing advances in neonatal care, the incidence of BPD has not improved. A potential explanation for this phenomenon is the limited ability for accurate early prediction of the risk of BPD. BPD continues to represent a therapeutic challenge and no single effective therapy exists for this condition. Areas covered: Here, we review risk factors of BPD derived from clinical data, biological fluid biomarkers, respiratory management data, and scientific advancements using 'omics' technologies, and their ability to predict the pathogenesis of BPD in preterm neonates. Risk factors and biomarkers were identified via literature search with a focus on the last 5 years of data. Expert opinion: The most accurate predictive tools utilize risk factors that encompass a variety of categories. Numerous predictive models have been proposed but suffer from a lack of adequate validation. An ideal model should include multiple, easily measurable variables validated across a heterogeneous population. In addition to evaluating recent BPD prediction models, we suggest approaches to enhance future models.

Should phenotype of previous preterm birth influence management of women with short cervix in subsequent pregnancy? Comparison of vaginal progesterone and Arabin pessary

OBJECTIVE

To investigate whether the classification of a previous spontaneous preterm birth (sPTB) as preterm labor (PTL) with intact membranes (IM) or as preterm prelabor rupture of membranes (PPROM) impacts the efficacy of cervical pessary or vaginal progesterone for prevention of sPTB in pregnant women with short cervix on transvaginal ultrasound.

METHODS

This was a retrospective cohort study of asymptomatic high-risk singleton pregnancies with a short cervix and history of sPTB, treated using Arabin pessary or vaginal progesterone for primary PTB prevention, conducted at four European hospitals. A log-rank test on Kaplan-Meier curves was used to assess the difference in performance of pessary and progesterone, according to history of PTL-IM or PPROM. Linear regression analysis was used to evaluate significant predictors of gestational age at delivery.

RESULTS

Between 2008 and 2015, 170 women were treated with a pessary and 88 with vaginal progesterone. In women treated with a pessary, rate of sPTB < 34 weeks was 16% in those with a history of PTL-IM and 55% in those with a history of PPROM. In women treated with progesterone, rate of sPTB < 34 weeks was 13% in those with a history of PTL-IM and 21% in those with a history of PPROM. Treatment with a pessary resulted in earlier delivery in women with previous PPROM than in any other subgroup (P < 0.0001). Linear regression analysis showed a clear effect of PPROM history (P < 0.0001), combination of PPROM history and treatment (P = 0.0003) and cervical length (P = 0.0004) on gestational age at birth.

CONCLUSIONS

Cervical pessary may be a less efficacious treatment option for women with previous PPROM; however, these results require prospective validation before change in practice is recommended. Phenotype of previous preterm birth may be an important risk predictor and treatment effect modifier; this information should be reported in future clinical trials. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Genomic and molecular characterization of preterm birth

Preterm birth (PTB) complications are the leading cause of long-term morbidity and mortality in children. By using whole blood samples, we integrated whole-genome sequencing (WGS), RNA sequencing (RNA-seq), and DNA methylation data for 270 PTB and 521 control families. We analyzed this combined dataset to identify genomic variants associated with PTB and secondary analyses to identify variants associated with very early PTB (VEPTB) as well as other subcategories of disease that may contribute to PTB. We identified differentially expressed genes (DEGs) and methylated genomic loci and performed expression and methylation quantitative trait loci analyses to link genomic variants to these expression and methylation changes. We performed enrichment tests to identify overlaps between new and known PTB candidate gene systems. We identified 160 significant genomic variants associated with PTB-related phenotypes. The most significant variants, DEGs, and differentially methylated loci were associated with VEPTB. Integration of all data types identified a set of 72 candidate biomarker genes for VEPTB, encompassing genes and those previously associated with PTB. Notably, PTB-associated genes RAB31 and RBPJ were identified by all three data types (WGS, RNA-seq, and methylation). Pathways associated with VEPTB include EGFR and prolactin signaling pathways, inflammation- and immunity-related pathways, chemokine signaling, IFN-γ signaling, and Notch1 signaling. Progress in identifying molecular components of a complex disease is aided by integrated analyses of multiple molecular data types and clinical data. With these data, and by stratifying PTB by subphenotype, we have identified associations between VEPTB and the underlying biology.

Genetic variants associated with patent ductus arteriosus in extremely preterm infants

OBJECTIVE

Patent ductus arteriosus (PDA) is a commonly observed condition in preterm infants. Prior studies have suggested a role for genetics in determining spontaneous ductal closure. Using samples from a large neonatal cohort we tested the hypothesis that common genetic variations are associated with PDA in extremely preterm infants.

STUDY DESIGN

Preterm infants (n = 1013) enrolled at NICHD Neonatal Research Network sites were phenotyped for PDA. DNA was genotyped for 1634 single nucleotide polymorphisms (SNPs) from candidate genes. Analyses were adjusted for ancestral eigenvalues and significant epidemiologic variables.

RESULTS

SNPs in several genes were associated with the clinical diagnosis of PDA and with surgical ligation in extremely preterm neonates diagnosed with PDA (p < 0.01). None of the associations were significant after correction for multiple comparisons.

CONCLUSION

We identified several common genetic variants associated with PDA. These findings may inform further studies on genetic risk factors for PDA in preterm infants.

Quantitative Proteomics by SWATH-MS of Maternal Plasma Exosomes Determine Pathways Associated With Term and Preterm Birth

Exosomes are membrane-bound nanovesicles that transport molecular signals between cells. This study determined changes in maternal plasma exosome proteomics contents in term and preterm births. Maternal plasma (MP) samples were collected from group 1: term not in labor (TNIL, n = 13); group 2: term in labor (TL, n = 11); group 3: preterm premature rupture of membranes (pPROM, n = 8); and group 4: preterm birth (PTB, n = 13). Exosomes isolated from plasma by differential density centrifugation followed by size exclusion chromatography were characterized by morphology (electron microscopy), quantity and size (nanoparticle tracking analysis), and markers (western blot). A quantitative, information-independent acquisition [sequential windowed acquisition of all theoretical mass spectra (SWATH-MS)] approach was used to determine the protein profile in exosomes. Ingenuity Pathway Analysis determined pathways associated with the protein profile identified in exosomes. MP exosomes were spherical, had a mean diameter of 120 nm, and were positive for exosomal proteins CD63 and TSG101 irrespective of pregnancy status. No distinct changes in exosome quantities were seen in maternal circulation across the groups. SWATH-MS identified 72 statistically significant proteins across the groups studied. Bioinformatics analysis showed the proteins within the exosomes in TNIL, TL, pPROM, and PTB target pathways mainly associated with inflammatory and metabolic signals. Exosomal data suggest that homeostatic imbalances, specifically inflammatory and endocrine signaling, might disrupt pregnancy maintenance resulting in labor-related changes both at term and preterm. Reflection of physiologic changes in exosomes is suggestive of its usefulness as biomarkers and cellular function indicators.

Progestins Inhibit Tumor Necrosis Factor α-Induced Matrix Metalloproteinase 9 Activity via the Glucocorticoid Receptor in Primary Amnion Epithelial Cells

Progestins have been recommended for preterm birth prevention in high-risk women; however, their mechanism of action still remains an area of debate. Medroxyprogesterone acetate (MPA) has previously been shown to significantly inhibit tumor necrosis factor α (TNFα)-induced matrix metalloproteinase 9 (MMP9) messenger RNA (mRNA) expression and activity in primary amnion epithelial cells, a process that may lead to preterm premature rupture of membranes. A mechanism that explains MPA's inhibition of TNFα-induced MMP9 mRNA expression and activity in primary amnion epithelial cells is unclear since these cells lack the classic nuclear progesterone receptor but express a membrane-associated progesterone receptor-progesterone receptor membrane component 1 (PGRMC1) along with the glucocorticoid receptor (GR). Primary amnion epithelial cells harvested from healthy term pregnant women at cesarean section were treated with PGRMC1 (to knockdown PGRMC1 expression), GR (to knockdown GR expression), or control small interfering RNA (siRNA; 10 nm) for 72 hours, pretreated with ethanol or MPA (10^-6 M) for 6 hours, and then stimulated with or without TNFα 10 ng/mL for 24 hours. Real-time quantitative polymerase chain reaction and gelatin zymography were used to quantify MMP9 mRNA expression and activity, respectively. Experimental groups were compared using 1-way analysis of variance. Both TNFα-induced MMP9 mRNA expression and activity were significantly inhibited by pretreatment with MPA; however, only the inhibition of TNFα-induced MMP9 activity was partially reversed with PGRMC1 siRNA. However, GR siRNA reversed both the inhibition of TNFα-induced MMP9 mRNA expression and activity by MPA. This study demonstrates that MPA mediates its anti-inflammatory effects primarily through GR and partially through PGRMC1 in primary amnion epithelial cells.

Mid-trimester preterm premature rupture of membranes (PPROM): etiology, diagnosis, classification, international recommendations of treatment options and outcome

Mid-trimester preterm premature rupture of membranes (PPROM), defined as rupture of fetal membranes prior to 28 weeks of gestation, complicates approximately 0.4%-0.7% of all pregnancies. This condition is associated with a very high neonatal mortality rate as well as an increased risk of long- and short-term severe neonatal morbidity. The causes of the mid-trimester PPROM are multifactorial. Altered membrane morphology including marked swelling and disruption of the collagen network which is seen with PPROM can be triggered by bacterial products or/and pro-inflammatory cytokines. Activation of matrix metalloproteinases (MMP) have been implicated in the mechanism of PPROM. The propagation of bacteria is an important contributing factor not only in PPROM, but also in adverse neonatal and maternal outcomes after PPROM. Inflammatory mediators likely play a causative role in both disruption of fetal membrane integrity and activation of uterine contraction. The "classic PPROM" with oligo/an-hydramnion is associated with a short latency period and worse neonatal outcome compared to similar gestational aged neonates delivered without antecedent PPROM. The "high PPROM" syndrome is defined as a defect of the chorio-amniotic membranes, which is not located over the internal cervical os. It may be associated with either a normal or reduced amount of amniotic fluid. It may explain why sensitive biochemical tests such as the Amniosure (PAMG-1) or IGFBP-1/alpha fetoprotein test can have a positive result without other signs of overt ROM such as fluid leakage with Valsalva. The membrane defect following fetoscopy also fulfils the criteria for "high PPROM" syndrome. In some cases, the rupture of only one membrane - either the chorionic or amniotic membrane, resulting in "pre-PPROM" could precede "classic PPROM" or "high PPROM". The diagnosis of PPROM is classically established by identification of nitrazine positive, fern positive watery leakage from the cervical canal observed during in specula investigation. Other more recent diagnostic tests include the vaginal swab assay for placental alpha macroglobulin-1 test or AFP and IGFBP1. In some rare cases amniocentesis and infusion of indigo carmine has been used to confirm the diagnosis of PPROM. The management of the PPROM requires balancing the potential neonatal benefits from prolongation of the pregnancy with the risk of intra-amniotic infection and its consequences for the mother and infant. Close monitoring for signs of chorioamnionitis (e.g. body temperature, CTG, CRP, leucocytes, IL-6, procalcitonine, amniotic fluid examinations) is necessary to minimize the risk of neonatal and maternal complications. In addition to delayed delivery, broad spectrum antibiotics of penicillin or cephalosporin group and/or macrolide and corticosteroids have been show to improve neonatal outcome [reducing risk of chorioamnionitis (average risk ratio (RR)=0.66), neonatal infections (RR=0.67) and abnormal ultrasound scan of neonatal brain (RR=0.67)]. The positive effect of continuous amnioinfusion through the subcutaneously implanted perinatal port system with amniotic fluid like hypo-osmotic solution in "classic PPROM" less than 28/0 weeks' gestation shows promise but must be proved in future prospective randomized studies. Systemic antibiotics administration in "pre-PPROM" without infection and hospitalization are also of questionable benefit and needs to be further evaluated in well-designed randomized prospective studies to evaluate if it is associated with any neonatal benefit as well as the relationship to possible adverse effect of antibiotics on to fetal development and neurological outcome.

Influence of MBL2 and NOS3 polymorphisms on spontaneous preterm birth in North East Brazil: genetics and preterm birth

Background: The mannose-binding lectin (MBL2) and nitric oxide synthase 3 (NOS3) genes are associated with the immune response against inflammatory processes, have been reported as possibly related with premature birth. Until now, most of the researches regarding the genetic influence of prematurity have revealed limited results because only investigating the child or the mothers' genotypes, thus not exploring the possible effects of interactions between these genotypes or the interactions with environmental factors related to the duration of pregnancy.Objective: We performed a replica study investigating the influence of single nucleotide polymorphisms (SNPs) in MBL2 and NOS3 genes on premature birth, also considering socioeconomic, demographic, and gestational factors.Materials and methods: We conducted a case-control study with 189 mother-infant dyads, with 104 spontaneous preterm births and 85 term births from Recife, Brazil. We used peripheral blood samples and umbilical cord samples to extract DNA. Functional SNPs at exon 1 and promoter region of MBL2 and NOS3 RS1799983 SNP were genotyped using direct sequencing and fluorescent allelic specific TaqMan^® assays respectively. Data were analyzed using the Statistical Package for the Social Sciences (SPSS^®) program with bivariate association and logistic multivariate regression tests.Results: We observed a prevalence of MBL2 wild-type genotype in the mother-infant dyad of the preterm group and polymorphic genotype in the mother-infant dyad of term birth. The haplotype LYA predominated in our sample, being more frequent in the preterm group, while the haplotype LYB, correlated with lower levels of MBL protein, was more frequent in the term birth group. About NOS3 RS1799983 SNP, the G/G genotype was more frequent throughout the sample. The heterozygous genotype predominated among women from the preterm group, showed a borderline difference between the groups. When MBL2 genotypes of the mother and son were analyzed together, codon 54 of MBL2 remained associated with prematurity. When the variables with p value lower than .20 in the bivariate analysis were analyzed by logistic regression, the low weight of the pregnant woman in relation to the gestational age, the occurrence of preterm premature rupture of membranes, urinary tract infection during birth and maternal history of other premature births were risk factors to prematurity. On the other hand, the presence of B allele at codon 54 of maternal MBL2 was a protective factor for the occurrence of spontaneous premature birth. In contrast, a borderline association was established between the maternal genetic variation within NOS3 gene and the outcome studied.Conclusions: Our study, limited by the small number of patients enrolled, indicates that MBL2 and NOS3 functional SNPs are associated with the occurrence of spontaneous prematurity and the regulation of the maternal inflammatory response. Despite these results are in agreement with previously reports, our findings do not replicate the ones reported in a large genome-wide association study performed on quite high number of subjects. Thus, we can conclude that MBL2 and NOS3 functional SNPs are plausible candidate risk factors just in few preterm birth cases, and consequently they cannot be included in the general diagnostic practice.

Whole exome sequencing reveals HSPA1L as a genetic risk factor for spontaneous preterm birth

Preterm birth is a leading cause of morbidity and mortality in infants. Genetic and environmental factors play a role in the susceptibility to preterm birth, but despite many investigations, the genetic basis for preterm birth remain largely unknown. Our objective was to identify rare, possibly damaging, nucleotide variants in mothers from families with recurrent spontaneous preterm births (SPTB). DNA samples from 17 Finnish mothers who delivered at least one infant preterm were subjected to whole exome sequencing. All mothers were of northern Finnish origin and were from seven multiplex families. Additional replication samples of European origin consisted of 93 Danish sister pairs (and two sister triads), all with a history of a preterm delivery. Rare exonic variants (frequency <1%) were analyzed to identify genes and pathways likely to affect SPTB susceptibility. We identified rare, possibly damaging, variants in genes that were common to multiple affected individuals. The glucocorticoid receptor signaling pathway was the most significant (p<1.7e-8) with genes containing these variants in a subgroup of ten Finnish mothers, each having had 2-4 SPTBs. This pathway was replicated among the Danish sister pairs. A gene in this pathway, heat shock protein family A (Hsp70) member 1 like (HSPA1L), contains two likely damaging missense alleles that were found in four different Finnish families. One of the variants (rs34620296) had a higher frequency in cases compared to controls (0.0025 vs. 0.0010, p = 0.002) in a large preterm birth genome-wide association study (GWAS) consisting of mothers of general European ancestry. Sister pairs in replication samples also shared rare, likely damaging HSPA1L variants. Furthermore, in silico analysis predicted an additional phosphorylation site generated by rs34620296 that could potentially affect chaperone activity or HSPA1L protein stability. Finally, in vitro functional experiment showed a link between HSPA1L activity and decidualization. In conclusion, rare, likely damaging, variants in HSPA1L were observed in multiple families with recurrent SPTB.

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.

Linking autoimmunity to the origin of the adaptive immune system

In jawed vertebrates, the adaptive immune system (AIS) cooperates with the innate immune system (IIS) to protect hosts from infections. Although targeting non-self-components, the AIS also generates self-reactive antibodies which, when inadequately counter-selected, can give rise to autoimmune diseases (ADs). ADs are on the rise in western countries. Why haven’t ADs been eliminated during the evolution of a ∼500 million-year old system? And why have they become more frequent in recent decades? Self-recognition is an attribute of the phylogenetically more ancient IIS and empirical data compellingly show that some self-reactive antibodies, which are classifiable as elements of the IIS rather then the AIS, may protect from (rather than cause) ADs. Here, we propose that the IIS’s self-recognition system originally fathered the AIS and, as a consequence of this relationship, its activity is dampened in hygienic environments. Rather than a mere breakdown or failure of the mechanisms of self-tolerance, ADs might thus arise from architectural constraints.

Translational Systems Pharmacology Studies in Pregnant Women

Pregnancy involves rapid physiological adaptation and complex interplay between mother and fetus. New analytic technologies provide large amounts of genomic, proteomic, and metabolomics data. The integration of these data through bioinformatics, statistical, and systems pharmacology techniques can improve our understanding of the mechanisms of normal maternal physiologic changes and fetal development. New insights into the mechanisms of pregnancy‐related disorders, such as preterm birth (PTB), may lead to the development of new therapeutic interventions and novel biomarkers.

Mutations in fetal genes involved in innate immunity and host defense against microbes increase risk of preterm premature rupture of membranes (PPROM)

BACKGROUND

Twin studies have revealed a significant contribution of the fetal genome to risk of preterm birth. Preterm premature rupture of membranes (PPROM) is the leading identifiable cause of preterm delivery. Infection and inflammation of the fetal membranes is commonly found associated with PPROM.

METHODS

We carried out whole exome sequencing (WES) of genomic DNA from neonates born of African-American mothers whose pregnancies were complicated by PPROM (76) or were normal term pregnancies (N = 43) to identify mutations in 35 candidate genes involved in innate immunity and host defenses against microbes. Targeted genotyping of mutations in the candidates discovered by WES was conducted on an additional 188 PPROM cases and 175 controls.

RESULTS

We identified rare heterozygous nonsense and frameshift mutations in several of the candidate genes, including CARD6, CARD8, DEFB1, FUT2, MBL2, NLP10, NLRP12, and NOD2. We discovered that some mutations (CARD6, DEFB1, FUT2, MBL2, NLRP10, NOD2) were present only in PPROM cases.

CONCLUSIONS

We conclude that rare damaging mutations in innate immunity and host defense genes, the majority being heterozygous, are more frequent in neonates born of pregnancies complicated by PPROM. These findings suggest that the risk of preterm birth in African-Americans may be conferred by mutations in multiple genes encoding proteins involved in dampening the innate immune response or protecting the host against microbial infection and microbial products.

Q192R polymorphism in the PON1 gene and familial hypercholesterolemia in a Saudi population

BACKGROUND

Familial hypercholesterolemia (FH) is an autosomal dominant condition characterized by abnormal levels of low-density lipoprotein (LDL) in the blood. FH is a risk factor for atherosclerosis and cardiovascular disease. The relationship between the paraoxonase 1 (PON1) gene, atherosclerosis and coronary artery disease has not been studied in Saudi patients.

OBJECTIVE

To investigate the genetic associations of the Q192R polymorphism in the PON1 gene with FH in Saudi patients.

DESIGN

Case-control study.

SETTING

Tertiary care center, Riyadh.

METHODS

Two hundred Saudi patients were enrolled in this study, including 100 patients with FH and 100 healthy controls, during the period from January 2012 to March 2013. Serum was separated from coagulated blood (3 mL) and used for analysis of lipid profiles. Genomic DNA was isolated from anticoagulant-treated blood (2 mL). Genotyping for the Q192R polymorphism was performed by polymerase chain reaction-restriction fragment length polymorphism analysis, followed by 3% agarose gel electrophoresis.

MAIN OUTCOME MEASURE

The strength of association between the Q192R polymorphism and FH in the Saudi population.

RESULTS

We confirmed that QR versus QQ (odds ratio [OR]: 1.55; 95% confidence interval [CI]: 1.05-3.43; P=.03), QR+RR versus QQ (OR: 1.98; 95% CI: 1.13-3.49; P=.01), and R versus Q (OR: 1.68; 95% CI: 1.09- 2.59; P=.01) in the Q192R polymorphism were associated with FH in the Saudi population.

CONCLUSION

In conclusion, the Q192R polymorphism in the PON1 gene is associated with FH in the Saudi population. Our results confirmed that the R allele, QR, and dominant model genotypes were associated with FH.

LIMITATION

Only a single variant (Q192R) was analyzed, and the medical and family histories of the patients were not known.

Association of candidate gene polymorphisms with clinical subtypes of preterm birth in a Latin American population

BackgroundPreterm birth (PTB) is the leading cause of neonatal mortality and morbidity. PTB is often classified according to clinical presentation as follows: idiopathic (PTB-I), preterm premature rupture of membranes (PTB-PPROM), and medically induced (PTB-M). The aim of this study was to evaluate the associations between specific candidate genes and clinical subtypes of PTB.MethodsTwenty-four single-nucleotide polymorphisms (SNPs) were genotyped in 18 candidate genes in 709 infant triads. Of them, 243 were PTB-I, 256 were PTB-PPROM, and 210 were PTB-M. These data were analyzed with a Family-Based Association.ResultsPTB was nominally associated with rs2272365 in PON1, rs883319 in KCNN3, rs4458044 in CRHR1, and rs610277 in F3. Regarding clinical subtypes analysis, three SNPs were associated with PTB-I (rs2272365 in PON1, rs10178458 in COL4A3, and rs4458044 in CRHR1), rs610277 in F3 was associated with PTB-PPROM, and rs883319 in KCNN3 and rs610277 in F3 were associated with PTB-M.ConclusionOur study identified polymorphisms potentially associated with specific clinical subtypes of PTB in this Latin American population. These results could suggest a specific role of such genes in the mechanisms involved in each clinical subtype. Further studies are required to confirm our results and to determine the role of these genes in the pathophysiology of clinical subtypes.

Association of SP-B gene 9306 A/G polymorphism (rs7316) and risk of RDS

BACKGROUND

Respiratory distress syndrome (RDS) is a severe pulmonary disease predominantly affects preterm newborns. Polymorphisms of surfactant-protein genes have been mostly evaluated as the candidate contributors in genetics of RDS. However the results are divers in different studies. We aimed at investigating the association of surfactant protein B (SPB) gene 9306 A/G polymorphism (rs7316) with RDS development.

METHOD

Three hundred and eighty newborns with gestational age of less than 34 weeks were included in a multicenter case-control study. Respiratory distress (RD) was scored according to Downes' scoring system. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used for genotyping.

RESULT

One hundred and eighty-four neonates showed RDS and 196 did not. Gestational age (GA) was significantly lower in the RDS group compared with the controls. AA genotype and A allele were found more frequently in the RDS group than the controls (96.2% versus 63.8% and 98.1% versus 80.6%, respectively) (p =.0001).

CONCLUSIONS

This is the first report of association of SFTPB rs7316 polymorphism with RDS development in Iranian newborns. The current study suggests that GA <28-weeks is the most important factor in predisposition to RDS. Genetic background in terms of SP-B gene might be involved in predisposition to RDS in premature neonates.

The preterm cervix reveals a transcriptomic signature in the presence of premature prelabor rupture of membranes

BACKGROUND

Premature prelabor rupture of fetal membranes accounts for 30% of all premature births and is associated with detrimental long-term infant outcomes. Premature cervical remodeling, facilitated by matrix metalloproteinases, may trigger rupture at the zone of the fetal membranes overlying the cervix. The similarities and differences underlying cervical remodeling in premature prelabor rupture of fetal membranes and spontaneous preterm labor with intact membranes are unexplored.

OBJECTIVES

We aimed to perform the first transcriptomic assessment of the preterm human cervix to identify differences between premature prelabor rupture of fetal membranes and preterm labor with intact membranes and to compare the enzymatic activities of matrix metalloproteinases-2 and -9 between premature prelabor rupture of fetal membranes and preterm labor with intact membranes.

STUDY DESIGN

Cervical biopsies were collected following preterm labor with intact membranes (n = 6) and premature prelabor rupture of fetal membranes (n = 5). Biopsies were also collected from reference groups at term labor (n = 12) or term not labor (n = 5). The Illumina HT-12 version 4.0 BeadChips microarray was utilized, and a novel network graph approach determined the specificity of changes between premature prelabor rupture of fetal membranes and preterm labor with intact membranes. Quantitative reverse transcription-polymerase chain reaction and Western blotting confirmed the microarray findings. Immunofluorescence was used for localization studies and gelatin zymography to assess matrix metalloproteinase activity.

RESULTS

PML-RARA-regulated adapter molecule 1, FYVE-RhoGEF and PH domain-containing protein 3 and carcinoembryonic antigen-ralated cell adhesion molecule 3 were significantly higher, whereas N-myc downstream regulated gene 2 was lower in the premature prelabor rupture of fetal membranes cervix when compared with the cervix in preterm labor with intact membranes, term labor, and term not labor. PRAM1 and CEACAM3 were localized to immune cells at the cervical stroma and NDRG2 and FGD3 were localized to cervical myofibroblasts. The activity of matrix metalloproteinase-9 was higher (1.22 ± 4.403-fold, P < .05) in the cervix in premature prelabor rupture of fetal membranes compared with preterm labor with intact membranes.

CONCLUSION

We identified 4 novel proteins with a potential role in the regulation of cervical remodeling leading to premature prelabor rupture of fetal membranes. Our findings contribute to the studies dissecting the mechanisms underlying premature prelabor rupture of fetal membranes and inspire further investigations toward the development of premature prelabor rupture of fetal membranes therapeutics.

Fetal de novo mutations and preterm birth

Preterm birth (PTB) affects ~12% of pregnancies in the US. Despite its high mortality and morbidity, the molecular etiology underlying PTB has been unclear. Numerous studies have been devoted to identifying genetic factors in maternal and fetal genomes, but so far few genomic loci have been associated with PTB. By analyzing whole-genome sequencing data from 816 trio families, for the first time, we observed the role of fetal de novo mutations in PTB. We observed a significant increase in de novo mutation burden in PTB fetal genomes. Our genomic analyses further revealed that affected genes by PTB de novo mutations were dosage sensitive, intolerant to genomic deletions, and their mouse orthologs were likely developmentally essential. These genes were significantly involved in early fetal brain development, which was further supported by our analysis of copy number variants identified from an independent PTB cohort. Our study indicates a new mechanism in PTB occurrence independently contributed from fetal genomes, and thus opens a new avenue for future PTB research.

Preterm birth is a prevalent pregnancy condition and leads to substantial morbidity and mortality. Its genetic association has been well observed, but the underlying etiology remains unclear. Current research has been focused on identifying risk factors in maternal genomes. In this study, we tested an unexplored hypothesis that preterm birth could be independently influenced by fetal genomes. We analyzed fetal de novo mutations, those not inherited from parents, from 816 trio families, and found preterm infants tended to have increased de novo mutation rates compared to infants born at term. Importantly, we also observed that these preterm-associated de novo mutations preferentially affect dosage sensitive genes that are essential in embryonic development, and these affected genes are involved in early fetal brain development. Overall, our study for the first time showed the fetal genetic contribution to preterm birth, and suggested abnormal fetal development as a potential cause for preterm birth.

Rare mutations and potentially damaging missense variants in genes encoding fibrillar collagens and proteins involved in their production are candidates for risk for preterm premature rupture of membranes

Preterm premature rupture of membranes (PPROM) is the leading identifiable cause of preterm birth with ~ 40% of preterm births being associated with PPROM and occurs in 1% - 2% of all pregnancies. We hypothesized that multiple rare variants in fetal genes involved in extracellular matrix synthesis would associate with PPROM, based on the assumption that impaired elaboration of matrix proteins would reduce fetal membrane tensile strength, predisposing to unscheduled rupture. We performed whole exome sequencing (WES) on neonatal DNA derived from pregnancies complicated by PPROM (49 cases) and healthy term deliveries (20 controls) to identify candidate mutations/variants. Genotyping for selected variants from the WES study was carried out on an additional 188 PPROM cases and 175 controls. All mothers were self-reported African Americans, and a panel of ancestry informative markers was used to control for genetic ancestry in all genetic association tests. In support of the primary hypothesis, a statistically significant genetic burden (all samples combined, SKAT-O p-value = 0.0225) of damaging/potentially damaging rare variants was identified in the genes of interest-fibrillar collagen genes, which contribute to fetal membrane strength and integrity. These findings suggest that the fetal contribution to PPROM is polygenic, and driven by an increased burden of rare variants that may also contribute to the disparities in rates of preterm birth among African Americans.

Renal injury in neonates: use of "omics" for developing precision medicine in neonatology

Preterm birth is associated with increased risks of morbidity and mortality along with increased healthcare costs. Advances in medicine have enhanced survival for preterm infants but the overall incidence of major morbidities has changed very little. Abnormal renal development is an important consequence of premature birth. Acute kidney injury (AKI) in the neonatal period is multifactorial and may increase lifetime risk of chronic kidney disease.Traditional biomarkers in newborns suffer from considerable confounders, limiting their use for early identification of AKI. There is a need to develop novel biomarkers that can identify, in real time, the evolution of renal dysfunction in an early diagnostic, monitoring and prognostic fashion. Use of "omics", particularly metabolomics, may provide valuable information regarding functional pathways underlying AKI and prediction of clinical outcomes.The emerging knowledge generated by the application of "omics" (genomics, proteomics, metabolomics) in neonatology provides new insights that can help to identify markers of early diagnosis, disease progression, and identify new therapeutic targets. Additionally, omics will have major implications in the field of personalized healthcare in the future. Here, we will review the current knowledge of different omics technologies in neonatal-perinatal medicine including biomarker discovery, defining as yet unrecognized biologic therapeutic targets, and linking of omics to relevant standard indices and long-term outcomes.