Outcome of pregnancy oral glucose tolerance test and preterm birth.

BACKGROUND: Gestational diabetes is associated with adverse outcomes such as preterm birth (<37 weeks). However, there is no international consensus on screening criteria or diagnostic levels for gestational diabetes, and it is unknown whether body mass index (BMI) or obesity modifies the relation between glucose level and preterm birth. METHODS: We studied a pregnancy cohort restricted to two Danish regions from the linked Danish Medical Birth Register to study associations between glucose measurements from the 2-hour post-load 75-gram oral glucose tolerance test (one-step approach) and preterm birth from 2004-2018. In Denmark, gestational diabetes screening is a targeted strategy for mothers with identified risk factors. We used Poisson regression to estimate rate ratios (RR) of preterm birth with z-standardized glucose measurements. We assessed effect measure modification by stratifying analyses and testing for heterogeneity. RESULTS: Among 11,337 pregnancies (6.2% delivered preterm), we observed an adjusted preterm birth RR of 1.2 (95% CI: 1.1-1.3) for a 1 standard deviation glucose increase of 1.4 mmol/L from the mean 6.7 mmol/L. There was evidence for effect measure modification by obesity, e.g., adjusted RR for non-obese (BMI <30): 1.2 (95%CI: 1.1-1.3) vs. obese (BMI ≥30): 1.3 (95%CI: 1.2-1.5), P=0.05 for heterogeneity. CONCLUSIONS: Among mothers screened for gestational diabetes, increased glucose levels, even those below the diagnostic level for gestational diabetes in Denmark, were associated with increased preterm birth risk. Obesity (BMI ≥30) may be an effect measure modifier, not just a confounder, of the relation between blood glucose and preterm birth risk.

Solving the Puzzle of Preterm Birth.

Solving the puzzle of preterm birth has been challenging and will require novel integrative solutions as preterm birth likely arises from many etiologies. It has been demonstrated that many sociodemographic and psychological determinants of preterm birth relate to its complex biology. It is this understanding that has enabled the development of a novel preventative strategy, which integrates the omics profile (genome, epigenome, transcriptome, proteome, metabolome, microbiome) with sociodemographic, environmental, and psychological determinants of individual pregnant people to solve the puzzle of preterm birth.

Ambient Environment and the Epidemiology of Preterm Birth.

Preterm birth (PTB) is associated with substantial mortality and morbidity. We describe environmental factors that may influence PTB risks. We focus on exposures associated with an individual's ambient environment, such as air pollutants, water contaminants, extreme heat, and proximities to point sources (oil/gas development or waste sites) and greenspace. These exposures may further vary by other PTB risk factors such as social constructs and stress. Future examinations of risks associated with ambient environment exposures would benefit from consideration toward multiple exposures - the exposome - and factors that modify risk including variations associated with the structural genome, epigenome, social stressors, and diet.

Genome-wide study of gene-by-sex interactions identifies risks for cleft palate.

Structural birth defects affect 3-4% of all live births and, depending on the type, tend to manifest in a sex-biased manner. Orofacial clefts (OFCs) are the most common craniofacial structural birth defects and are often divided into cleft lip with or without cleft palate (CL/P) and cleft palate only (CP). Previous studies have found sex-specific risks for CL/P, but these risks have yet to be evaluated in CP. CL/P is more common in males and CP is more frequently observed in females, so we hypothesized there would also be sex-specific differences for CP. Using a trio-based cohort, we performed sex-stratified genome-wide association studies (GWAS) based on proband sex followed by a genome-wide gene-by-sex (GxS) interaction testing. There were 13 loci significant for GxS interactions, with the top finding in LTBP1 (RR=3.37 [2.04 - 5.56], p=1.93x10 -6 ). LTBP1 plays a role in regulating TGF-B bioavailability, and knockdown in both mice and zebrafish lead to craniofacial anomalies. Further, there is evidence for differential expression of LTBP1 between males and females in both mice and humans. Therefore, we tested the association between the imputed genetically regulated gene expression of genes with significant GxS interactions and the CP phenotype. We found significant association for LTBP1 in cell cultured fibroblasts in female probands (p=0.0013) but not in males. Taken altogether, we show there are sex-specific risks for CP that are otherwise undetectable in a combined sex cohort, and LTBP1 is a candidate risk gene, particularly in females.

USING FÖRSTER RESONANCE ENERGY TRANSFER (FRET) TO UNDERSTAND THE UBIQUITINATION LANDSCAPE.

Förster resonance energy transfer (FRET) is a fluorescence technique that allows quantitative measurement of protein interactions, kinetics and dynamics. This review covers the use of FRET to study the structures and mechanisms of ubiquitination and related proteins. We survey FRET assays that have been developed where donor and acceptor fluorophores are placed on E1, E2 or E3 enzymes and ubiquitin (Ub) to monitor steady-state and real-time transfer of Ub through the ubiquitination cascade. Specialized FRET probes placed on Ub and Ub-like proteins have been developed to monitor Ub removal by deubiquitinating enzymes (DUBs) that result in a loss of a FRET signal upon cleavage of the FRET probes. FRET has also been used to understand conformational changes in large complexes such as multimeric E3 ligases and the proteasome, frequently using sophisticated single molecule methods. Overall, FRET is a powerful tool to help unravel the intricacies of the complex ubiquitination system.

A search for factors associated with reduced carbohydrate intake and NTD risk in two population-based studies.

BACKGROUND: Two population-based case-control studies have reported an increased risk of neural tube defect (NTD)-affected pregnancies among women with low carbohydrate diet in the periconceptional period. Given that only two studies have investigated this association, it is unclear to what degree the findings could be impacted by residual confounding. Here, we further interrogated both studies that observed this association with the objective to identify factors from a much larger number of factors that might explain the association. METHODS: By employing a machine learning algorithm (random forest), we investigated a baseline set of over 200 variables. These analyses produced the top 10 variables in each data set for cases and controls that predicted periconceptional low carbohydrate intake. RESULTS: Examining those prediction variables with logistic regression modeling, we did not observe any particular variable that substantially contributed to the NTD-low carbohydrate association in either data set. CONCLUSIONS: If there are underlying factors that explain the association, our findings suggest that none of the 200+ variables we examined were sufficiently correlated with what that true explanatory exposure may be. Alternatively, our findings may suggest that there are other unidentified factor(s) at play, or the association observed in two independent data sets is directly related to low carbohydrate intake.

Corrigendum: Advances and potential of omics studies for understanding the development of food allergy.

[This corrects the article DOI: 10.3389/falgy.2023.1149008.].

Vascular health years after a hypertensive disorder of pregnancy: The EPOCH study.

BACKGROUND: Preeclampsia is associated with a two-fold increase in a woman's lifetime risk of developing atherosclerotic cardiovascular disease (ASCVD), but the reasons for this association are uncertain. The objective of this study was to examine the associations between vascular health and a hypertensive disorder of pregnancy among women ≥ 2 years postpartum. METHODS: Pre-menopausal women with a history of either a hypertensive disorder of pregnancy (cases: preeclampsia or gestational hypertension) or a normotensive pregnancy (controls) were enrolled. Participants were assessed for standard ASCVD risk factors and underwent vascular testing, including measurements of blood pressure, endothelial function, and carotid artery ultrasound. The primary outcomes were blood pressure, ASCVD risk, reactive hyperemia index measured by EndoPAT and carotid intima-medial thickness. The secondary outcomes were augmentation index normalized to 75 beats per minute and pulse wave amplitude measured by EndoPAT, and carotid elastic modulus and carotid beta-stiffness measured by carotid ultrasound. RESULTS: Participants had a mean age of 40.7 years and were 5.7 years since their last pregnancy. In bivariate analyses, cases (N = 68) were more likely than controls (N = 71) to have hypertension (18% vs 4%, P = .034), higher calculated ASCVD risk (0.6 vs 0.4, P = .02), higher blood pressures (systolic: 118.5 vs 111.6 mm Hg, P = .0004; diastolic: 75.2 vs 69.8 mm Hg, P = .0004), and higher augmentation index values (7.7 vs 2.3, P = .03). They did not, however, differ significantly in carotid intima-media thickness (0.5 vs 0.5, P = .29) or reactive hyperemia index (2.1 vs 2.1, P = .93), nor in pulse wave amplitude (416 vs 326, P = .11), carotid elastic modulus (445 vs 426, P = .36), or carotid beta stiffness (2.8 vs 2.8, P = .86). CONCLUSION: Women with a prior hypertensive disorder of pregnancy had higher ASCVD risk and blood pressures several years postpartum, but did not have more endothelial dysfunction or subclinical atherosclerosis.

Hydroxychloroquine in Lupus Pregnancy and Risk of Preeclampsia.

OBJECTIVE: Systemic lupus erythematosus (SLE) disproportionately affects women during childbearing years, and hydroxychloroquine (HCQ) is the standard first-line treatment. Preeclampsia complicates up to one-third of pregnancies in lupus patients, although reports vary by parity and multifetal gestation. We investigated whether taking HCQ early in pregnancy may reduce the risk of preeclampsia. METHODS: We studied 1,068 live birth singleton pregnancies among 1,020 privately insured patients with SLE (2007-2016). HCQ treatment was defined as three months preconception through the first trimester, and prescription fills were a proxy for taking HCQ. Modified Poisson regression estimated risk ratios (RRs) and 95% confidence intervals (CIs), stratified by parity. Propensity scores accounted for confounders, and stratified analyses examined effect modification. RESULTS: Approximately 15% of pregnant patients were diagnosed with preeclampsia. In 52% of pregnancies, patients had one or more HCQ fills. Pregnant patients exposed to HCQ had more comorbidities, SLE activity, and azathioprine treatment. We found no evidence of a statistical association between HCQ and preeclampsia among nulliparous (RR 1.26 [95% CI 0.82-1.93]) and multiparous pregnancies (RR 1.20 [95% CI 0.80-1.70]). Additional controls for confounding decreased the RRs toward the null (nulliparous pregnancy, propensity score-adjusted [PS-adj] RR 1.09 [95% CI 0.68-1.76]; multiparous pregnancy, PS-adj RR 1.01 [95% CI 0.66-1.53]). CONCLUSION: Using a large insurance-based database, we did not observe a decreased risk of preeclampsia associated with HCQ treatment in pregnancy, although we cannot rule out residual and unmeasured confounding and misclassification. Further studies leveraging large population-based data and prospective collection could characterize how HCQ influences preeclampsia risk in pregnant patients with SLE and among persons at greater risk of hypertensive disorders of pregnancy.

Preconception dietary glycemic index and risk for large-for-gestational age births.

OBJECTIVES: Diets with a high glycemic index (GI) leading to elevated postprandial glucose levels and hyperinsulinemia during pregnancy have been inconsistently linked to an increased risk for large-for-gestational-age (LGA) births. The effects of prepregnancy dietary GI on LGA risk are, to our knowledge, unknown. We examined the association of prepregnancy dietary GI with LGA births and joint associations of GI and maternal overweight/obesity and infant sex with LGA births among 10 188 infants born without congenital anomalies from 1997 to 2011, using data from the National Birth Defects Prevention Study (NBDPS). The aim of this study was to investigate this association among infants without major congenital anomalies (controls) who participated in the NBDPS and to evaluate how prepregnancy BMI and infant sex may modify this association on the additive scale. METHODS: Dietary intake was ascertained using a 58-item food frequency questionnaire. We dichotomized dietary GI into high and low categories using spline regression models. Infants with a birth weight at or above the 90th percentile for gestational age and sex, according to a U.S. population reference, were considered LGA. We used logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Of the infants, 859 (9%) had a high dietary GI (cut-point: 59), and 1244 infants (12%) were born LGA. Unadjusted analysis suggested an inverse association between high dietary GI and LGA (OR, 0.79; 95% CI, 0.62-0.99). No association was observed in multivariable models when comparing high dietary GI intake between LGA births and all other births (OR, 0.94; 95% CI, 0.74-1.20) or when excluding small-for-gestational-age (SGA) births (OR, 0.94; 95% CI, 0.73-1.19). No joint associations with maternal overweight/obesity or infant sex were observed. CONCLUSION: High prepregnancy maternal GI was not associated with LGA births independently of or jointly with other factors.

Pregnancy Outcomes in a Diverse US Lupus Cohort.

OBJECTIVE: Although the population of patients with systemic lupus erythematosus (SLE) is racially and ethnically diverse, many study populations are homogeneous. Further, data are often lacking on critical factors, such as antiphospholipid antibodies (aPLs). We investigated live birth rates in patients with SLE at Kaiser Permanente Northern California, including race and ethnicity and aPL data. METHODS: Electronic health records of pregnancies with outcomes observed from 2011 to 2020 were identified among patients with SLE. Prevalent SLE was defined as two or more International Classification of Diseases-coded visits seven or more days apart before the last menstrual period. We summarized patient characteristics, medication orders, health care use, and medication use. Pregnancy outcomes (live birth, stillbirth, spontaneous abortion, ectopic pregnancy, and molar pregnancy) were presented overall and stratified by race and ethnicity, aPL status, and nephritis history. RESULTS: We identified 657 pregnancies among 453 patients with SLE. The cohort was diverse, reflecting the Northern California population (27% Asian, 26% Hispanic, 26% Non-Hispanic White, 13% Non-Hispanic Black, 5% multiracial, and approximately 2% Pacific Islander and Native American). Approximately 74% of observed pregnancies ended in live birth, 23% resulted in spontaneous abortion, 2% were ectopic or molar pregnancies, and <1% were stillbirths. There was limited variability in live births by race and ethnic group (72%-79%), aPL status (69.5%-77%), and nephritis history (71%-75%). CONCLUSION: Our findings are consistent with previous studies; however, some methodologic differences may yield a range of live birth rates. We found that approximately 74% of pregnancies in patients with SLE ended in live birth, with modest variability in spontaneous abortion by race and ethnicity, nephritis history, and aPL status.

Integrative analysis of noncoding mutations identifies the druggable genome in preterm birth.

Preterm birth affects ~10% of pregnancies in the US. Despite familial associations, identifying at-risk genetic loci has been challenging. We built deep learning and graphical models to score mutational effects at base resolution via integrating the pregnant myometrial epigenome and large-scale patient genomes with spontaneous preterm birth (sPTB) from European and African American cohorts. We uncovered previously unidentified sPTB genes that are involved in myometrial muscle relaxation and inflammatory responses and that are regulated by the progesterone receptor near labor onset. We studied genomic variants in these genes in our recruited pregnant women administered progestin prophylaxis. We observed that mutation burden in these genes was predictive of responses to progestin treatment for preterm birth. To advance therapeutic development, we screened ~4000 compounds, identified candidate molecules that affect our identified genes, and experimentally validated their therapeutic effects on regulating labor. Together, our integrative approach revealed the druggable genome in preterm birth and provided a generalizable framework for studying complex diseases.

Large-scale proteomics in the first trimester of pregnancy predict psychopathology and temperament in preschool children: an exploratory study.

BACKGROUND: Understanding the prenatal origins of children's psychopathology is a fundamental goal in developmental and clinical science. Recent research suggests that inflammation during pregnancy can trigger a cascade of fetal programming changes that contribute to vulnerability for the emergence of psychopathology. Most studies, however, have focused on a handful of proinflammatory cytokines and have not explored a range of prenatal biological pathways that may be involved in increasing postnatal risk for emotional and behavioral difficulties. METHODS: Using extreme gradient boosted machine learning models, we explored large-scale proteomics, considering over 1,000 proteins from first trimester blood samples, to predict behavior in early childhood. Mothers reported on their 3- to 5-year-old children's (N = 89, 51% female) temperament (Child Behavior Questionnaire) and psychopathology (Child Behavior Checklist). RESULTS: We found that machine learning models of prenatal proteomics predict 5%-10% of the variance in children's sadness, perceptual sensitivity, attention problems, and emotional reactivity. Enrichment analyses identified immune function, nervous system development, and cell signaling pathways as being particularly important in predicting children's outcomes. CONCLUSIONS: Our findings, though exploratory, suggest processes in early pregnancy that are related to functioning in early childhood. Predictive features included far more proteins than have been considered in prior work. Specifically, proteins implicated in inflammation, in the development of the central nervous system, and in key cell-signaling pathways were enriched in relation to child temperament and psychopathology measures.

Maternal physical activity, sitting, and risk of non-cardiac birth defects.

BACKGROUND: The relationship between maternal physical activity (PA)/sitting and birth defects is largely unexplored. We examined whether pre-pregnancy PA/sitting were associated with having a pregnancy affected by a birth defect. METHODS: We used data from two United States population-based case-control studies: 2008-2011 deliveries from the National Birth Defects Prevention Study (NBDPS; 9 states) and 2014-2018 deliveries from the Birth Defects Study To Evaluate Pregnancy exposureS (BD-STEPS; 7 states). Cases with one of 12 non-cardiac birth defects (n = 3798) were identified through population-based registries. Controls (n = 2682) were live-born infants without major birth defects randomly sampled using vital/hospital records. Mothers self-reported pre-pregnancy PA/sitting. Unconditional logistic regression models estimated associations between PA/sitting categories and the 12 birth defects. RESULTS: Mothers engaging in pre-pregnancy PA was associated with a reduced odds of five (spina bifida, cleft palate, anorectal atresia, hypospadias, transverse limb deficiency) and a higher odds of two (anencephaly, gastroschisis) birth defects. Mothers spending less time sitting in pre-pregnancy was associated with a reduced odds of two (anorectal atresia, hypospadias) and a higher odds of one (cleft lip with or without cleft palate) birth defect. CONCLUSIONS: Reasonable next steps include replication of these findings, improved exposure assessment, and elucidation of biologic mechanisms. IMPACT: Using data from two population-based case-control studies, we found that mothers engaging in different types of physical activity in the 3 months before pregnancy had an infant with a reduced odds of five and a higher odds of two birth defects. Mothers spending less time sitting in the 3 months before pregnancy had an infant with a reduced odds of two and a higher odds of one birth defect. Clarification and confirmation from additional studies are needed using more precise exposure measures, distinguishing occupational from leisure-time physical activity, and elucidation of mechanisms supporting these associations.

Factors associated with infant sex and preterm birth status for selected birth defects from the National Birth Defects Prevention Study, 1997-2011.

BACKGROUND: Birth defects and preterm birth co-occur, with some overlapping risk factors. Many birth defects and preterm births tend to have a male preponderance. We explored potential risk factors impacting sex and preterm (<37 weeks of gestation) birth differences among infants with selected birth defects delivered from 1997 to 2011 using data from the National Birth Defects Prevention Study (NBDPS). METHODS: The NBDPS was a large multisite, population-based case-control study. Using random forests, we identified important predictors of male preterm, female preterm, and male term, each compared with female term births for each birth defect. Using logistic regression, we estimated odds ratios for associations between important predictors and sex-preterm birth status by birth defect. RESULTS: We examined 11,379 infants with nine specific birth defects. The top 10 most important predictors of sex-preterm birth status from the random forests varied greatly across the birth defects and sex-preterm comparisons within a given defect group, with several being novel factors. However, one consistency was that short interpregnancy interval was associated with sex-preterm birth status for many of the studied birth defects. Although obesity has been identified as a risk factor for preterm birth and birth defects in other research, it was not associated with sex-preterm birth status for any of the examined defects. CONCLUSIONS: We confirmed expected associations for sex-preterm birth status differences and found new potential risk factors for further exploration among the studied birth defects.

Bias analyses to investigate the impact of differential participation: Application to a birth defects case-control study.

BACKGROUND: Certain associations observed in the National Birth Defects Prevention Study (NBDPS) contrasted with other research or were from areas with mixed findings, including no decrease in odds of spina bifida with periconceptional folic acid supplementation, moderately increased cleft palate odds with ondansetron use and reduced hypospadias odds with maternal smoking. OBJECTIVES: To investigate the plausibility and extent of differential participation to produce effect estimates observed in NBDPS. METHODS: We searched the literature for factors related to these exposures and participation and conducted deterministic quantitative bias analyses. We estimated case-control participation and expected exposure prevalence based on internal and external reports, respectively. For the folic acid-spina bifida and ondansetron-cleft palate analyses, we hypothesized the true odds ratio (OR) based on prior studies and quantified the degree of exposure over- (or under-) representation to produce the crude OR (cOR) in NBDPS. For the smoking-hypospadias analysis, we estimated the extent of selection bias needed to nullify the association as well as the maximum potential harmful OR. RESULTS: Under our assumptions (participation, exposure prevalence, true OR), there was overrepresentation of folic acid use and underrepresentation of ondansetron use and smoking among participants. Folic acid-exposed spina bifida cases would need to have been ≥1.2× more likely to participate than exposed controls to yield the observed null cOR. Ondansetron-exposed cleft palate cases would need to have been 1.6× more likely to participate than exposed controls if the true OR is null. Smoking-exposed hypospadias cases would need to have been ≥1.2 times less likely to participate than exposed controls for the association to falsely appear protective (upper bound of selection bias adjusted smoking-hypospadias OR = 2.02). CONCLUSIONS: Differential participation could partly explain certain associations observed in NBDPS, but questions remain about why. Potential impacts of other systematic errors (e.g. exposure misclassification) could be informed by additional research.

Large-scale correlation network construction for unraveling the coordination of complex biological systems.

Advanced measurement and data storage technologies have enabled high-dimensional profiling of complex biological systems. For this, modern multiomics studies regularly produce datasets with hundreds of thousands of measurements per sample, enabling a new era of precision medicine. Correlation analysis is an important first step to gain deeper insights into the coordination and underlying processes of such complex systems. However, the construction of large correlation networks in modern high-dimensional datasets remains a major computational challenge owing to rapidly growing runtime and memory requirements. Here we address this challenge by introducing CorALS (Correlation Analysis of Large-scale (biological) Systems), an open-source framework for the construction and analysis of large-scale parametric as well as non-parametric correlation networks for high-dimensional biological data. It features off-the-shelf algorithms suitable for both personal and high-performance computers, enabling workflows and downstream analysis approaches. We illustrate the broad scope and potential of CorALS by exploring perspectives on complex biological processes in large-scale multiomics and single-cell studies.

Rare variants in CAPN2 increase risk for isolated hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect (CHD) characterized by hypoplasia of the left ventricle and aorta along with stenosis or atresia of the aortic and mitral valves. HLHS represents only ∼4%-8% of all CHDs but accounts for ∼25% of deaths. HLHS is an isolated defect (i.e., iHLHS) in 70% of families, the vast majority of which are simplex. Despite intense investigation, the genetic basis of iHLHS remains largely unknown. We performed exome sequencing on 331 families with iHLHS aggregated from four independent cohorts. A Mendelian-model-based analysis demonstrated that iHLHS was not due to single, large-effect alleles in genes previously reported to underlie iHLHS or CHD in >90% of families in this cohort. Gene-based association testing identified increased risk for iHLHS associated with variation in CAPN2 (p = 1.8 × 10-5), encoding a protein involved in functional adhesion. Functional validation studies in a vertebrate animal model (Xenopus laevis) confirmed CAPN2 is essential for cardiac ventricle morphogenesis and that in vivo loss of calpain function causes hypoplastic ventricle phenotypes and suggest that human CAPN2707C>T and CAPN21112C>T variants, each found in multiple individuals with iHLHS, are hypomorphic alleles. Collectively, our findings show that iHLHS is typically not a Mendelian condition, demonstrate that CAPN2 variants increase risk of iHLHS, and identify a novel pathway involved in HLHS pathogenesis.