Effect of Estrogen Receptor Alpha on Cardiopulmonary Adaptation to Chronic Developmental Hypoxia in a Rat Model.

Humans living at high-altitude (HA) have adapted to this environment by increasing pulmonary vascular and alveolar growth. RNA sequencing data from a novel murine model that mimics this phenotypical response to HA suggested estrogen signaling via estrogen receptor alpha (ERα) may be involved in this adaptation. We hypothesized ERα was a key mediator in the cardiopulmonary adaption to chronic hypoxia and sought to delineate the mechanistic role ERα contributes to this process by exposing novel loss-of-function ERα mutant (ERαMut) rats to simulated HA. ERα mutant or wild type (wt) rats were exposed to normoxia or hypoxia starting at conception and continued postnatally until 6 weeks of age. Both wt and ERαMut animals born and raised in hypoxia exhibited lower body mass and higher hematocrits, total alveolar volumes (Va), diffusion capacities of carbon monoxide (DLCO), pulmonary arteriole (PA) wall thickness, and Fulton indices than normoxia animals. Right ventricle adaptation was maintained in the setting of hypoxia. While no major physiologic differences were seen between wt and ERαMut animals at either exposure, ERαMut animals exhibited smaller mean linear intercepts (MLI) and increased PA total and lumen areas. Hypoxia exposure or ERα loss-of-function did not affect lung mRNA abundance of vascular endothelial growth factor, angiopoietin 2 or apelin. Sexual dimorphisms were noted in PA wall thickness and lumen area in ERαMut rats. In summary, in room air-exposed rats and rats with peri- and postnatal hypoxia exposure, ERα loss-of-function was associated with decreased alveolar size (primarily driven by hypoxic animals) and increased PA remodeling.

Vitamin C Supplementation Among Pregnant Smokers and Airway Function Trajectory in Offspring: A Secondary Analysis of a Randomized Clinical Trial.

This secondary analysis of a randomized clinical trial analyzes the association of vitamin C supplementation in women who smoked during pregnancy with airway function trajectory in their offspring at 4 to 6 years of age.

Decreased vascular reactivity associated with increased IL-8 in 6-month-old infants of mothers with pre-eclampsia.

BACKGROUND: Offspring born to mothers with pre-eclampsia (Pre-E) suffer higher risks of adult cardiovascular diseases, suggesting that exposure to an antiangiogenic environment in-utero has a lasting impact on the development of endothelial function. The goal of this study is to test the hypothesis that in-utero exposure to Pre-E results in alterations of angiogenic factors/cytokines that negatively impact vascular development during infancy. METHODS: Infants born from mothers with and without Pre-E were recruited and followed up at 6 months. Plasma cytokines, blood pressure, microvessel density, and vascular reactivity were assessed. RESULTS: 6-month-old infants born to mothers with Pre-E had unchanged blood pressure (p = 0.86) and microvessel density (p = 0.57). Vascular reactivity was decreased in infants born to mothers with Pre-E compared to infants born to healthy mothers (p = 0.0345). Interleukin 8 (IL-8) (p = 0.03) and Angiopoeitin-2 (Ang-2) (p = 0.04) were increased in infants born to mothers with Pre-E. We observed that higher IL-8 was associated with lower vascular reactivity (rho = -0.14, p < 0.0001). CONCLUSION: At 6 months of age, infants born to mothers with Pre-E had impaired vascular reactivity and higher IL-8 and Ang-2, but similar blood pressure and microvessel density compared to infants born to non-Pre-E mothers. IMPACT STATEMENT: Changes in cord blood antiangiogenic factors are documented in infants of mothers with pre-eclampsia and may contribute to offspring risks of adult cardiovascular disease. How these factors evolve during early infancy and their correlation with offspring vascular development have not been studied. This study found that 6-month-old infants born to mothers with pre-eclampsia had decreased vascular reactivity, which was correlated with higher IL-8. These findings underscore the lasting impact of maternal pre-eclampsia on offspring vascular development and highlight the need for long-term follow-up in children born to mothers with pre-eclampsia.

Improvements in lung function following vitamin C supplementation to pregnant smokers are associated with buccal DNA methylation at 5 years of age.

BACKGROUND: We previously reported in the "Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function" randomized clinical trial (RCT) that vitamin C (500 mg/day) supplementation to pregnant smokers is associated with improved respiratory outcomes that persist through 5 years of age. The objective of this study was to assess whether buccal cell DNA methylation (DNAm), as a surrogate for airway epithelium, is associated with vitamin C supplementation, improved lung function, and decreased occurrence of wheeze. METHODS: We conducted epigenome-wide association studies (EWAS) using Infinium MethylationEPIC arrays and buccal DNAm from 158 subjects (80 placebo; 78 vitamin C) with pulmonary function testing (PFT) performed at the 5-year visit. EWAS were performed on (1) vitamin C treatment, (2) forced expiratory flow between 25 and 75% of expired volume (FEF25-75), and (3) offspring wheeze. Models were adjusted for sex, race, study site, gestational age at randomization (≤ OR > 18 weeks), proportion of epithelial cells, and latent covariates in addition to child length at PFT in EWAS for FEF25-75. We considered FDR p < 0.05 as genome-wide significant and nominal p < 0.001 as candidates for downstream analyses. Buccal DNAm measured in a subset of subjects at birth and near 1 year of age was used to determine whether DNAm signatures originated in utero, or emerged with age. RESULTS: Vitamin C treatment was associated with 457 FDR significant (q < 0.05) differentially methylated CpGs (DMCs; 236 hypermethylated; 221 hypomethylated) and 53 differentially methylated regions (DMRs; 26 hyper; 27 hypo) at 5 years of age. FEF25-75 was associated with one FDR significant DMC (cg05814800), 1,468 candidate DMCs (p < 0.001), and 44 DMRs. Current wheeze was associated with 0 FDR-DMCs, 782 candidate DMCs, and 19 DMRs (p < 0.001). In 365/457 vitamin C FDR significant DMCs at 5 years of age, there was no significant interaction between time and treatment. CONCLUSIONS: Vitamin C supplementation to pregnant smokers is associated with buccal DNA methylation in offspring at 5 years of age, and most methylation signatures appear to be persistent from the prenatal period. Buccal methylation at 5 years was also associated with current lung function and occurrence of wheeze, and these functionally associated loci are enriched for vitamin C associated loci. Clinical trial registration ClinicalTrials.gov, NCT01723696 and NCT03203603.

Chronic developmental hypoxia alters rat lung immune cell transcriptomes during allergic airway inflammation.

Populations that are born and raised at high altitude develop under conditions of chronic developmental hypoxia (CDH), which results in pulmonary adaptations of increased lung volume and diffusion capacity to increase gas exchange. It is not clear how CDH may alter allergic inflammation in the lung. In this study, we sought to characterize the impact of CDH on immune cell populations in the rat lung during a murine model of asthma. Rats were bred and raised in either hypoxic (15% oxygen, CDH) or normobaric room air (20% oxygen). At 3-weeks of age, animals were sensitized to ovalbumin (OVA) or physiologic saline (phosphate-buffered saline [PBS]) as a control, followed by three consecutive days of intra-nasal OVA or PBS at 6-weeks of age. We then assessed airway reactivity and allergic-associated cytokine levels. This was followed by single-cell transcriptomic profiling of lung cell populations. In scRNA-seq analysis, we assessed differentially expressed genes, differentially enriched functional pathways, immune cell exhaustion/activation markers, and immune cell secretory products. Our results show that while OVA heightened airway reactivity, CDH suppressed airway reactivity in OVA-challenged and control animals. Through scRNA-seq analysis, we further demonstrate that CDH alters the transcriptional landscape in the lung and alters transcriptional programs in immune cells. These data define CDH-dependent changes in the lung that impact airway reactivity.

Effect of Vitamin C Supplementation for Pregnant Smokers on Offspring Airway Function and Wheeze at Age 5 Years: Follow-up of a Randomized Clinical Trial.

Importance: Vitamin C supplementation (500 mg/d) for pregnant smokers has been reported to increase offspring airway function as measured by forced expiratory flow (FEF) through age 12 months; however, its effects on airway function at age 5 years remain to be assessed. Objective: To assess whether vitamin C supplementation in pregnant smokers is associated with increased and/or improved airway function in their offspring at age 5 years and whether vitamin C decreases the occurrence of wheeze. Design, Setting, and Participants: This study followed up the Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function (VCSIP) double-blind, placebo-controlled randomized clinical trial conducted at 3 centers in the US (in Oregon, Washington, and Indiana) between 2012 and 2016. Investigators and participants remain unaware of the treatment assignments. Forced expiratory flow measurements at age 5 years were completed from 2018 to 2021. Interventions: Pregnant smokers were randomized to vitamin C (500 mg/d) or placebo treatment. Main Outcomes and Measures: The primary outcome was the prespecified measurement of FEF between 25% and 75% expired volume (FEF25-75) by spirometry at age 5 years. Secondary outcomes included FEF measurements at 50% and 75% of expiration (FEF50 and FEF75), forced expiratory volume in 1 second (FEV1), and occurrence of wheeze. Results: Of the 251 pregnant smokers included in this study, 125 (49.8%) were randomized to vitamin C and 126 (50.2%) were randomized to placebo. Of 213 children from the VCSIP trial who were reconsented into this follow-up study, 192 (90.1%) had successful FEF measurements at age 5 years; 212 (99.5%) were included in the analysis of wheeze. Analysis of covariance demonstrated that offspring of pregnant smokers allocated to vitamin C compared with placebo had 17.2% significantly higher mean (SE) measurements of FEF25-75 at age 5 years (1.45 [0.04] vs 1.24 [0.04] L/s; adjusted mean difference, 0.21 [95% CI, 0.13-0.30]; P < .001). Mean (SE) measurements were also significantly increased by 14.1% for FEF50 (1.59 [0.04] vs 1.39 [0.04] L/s; adjusted mean difference, 0.20 [95% CI, 0.11-0.30]; P < .001), 25.9% for FEF75 (0.79 [0.02] vs 0.63 [0.02] L/s; 0.16 [95% CI, 0.11-0.22]; P < .001), and 4.4% for FEV1 (1.13 [0.02] vs 1.09 [0.02] L; 0.05 [95% CI, 0.01-0.09]; P = .02). In addition, offspring of pregnant smokers randomized to vitamin C had significantly decreased wheeze (28.3% vs 47.2%; estimated odds ratio, 0.41 [95% CI, 0.23-0.74]; P = .003). Conclusions and Relevance: In this follow-up study of offspring of pregnant smokers randomized to vitamin C vs placebo, vitamin C supplementation during pregnancy resulted in significantly increased airway function of offspring at age 5 years and significantly decreased the occurrence of wheeze. These findings suggest that vitamin C supplementation for pregnant smokers may decrease the effects of smoking in pregnancy on childhood airway function and respiratory health. Trial Registration: ClinicalTrials.gov Identifier: NCT03203603.

Long-term childhood outcomes for babies born at term who were exposed to antenatal corticosteroids.

BACKGROUND: Antenatal corticosteroids improve neonatal outcomes when administered to infants who are at risk of preterm delivery. Many women who receive antenatal corticosteroids for threatened preterm labor proceed to deliver at term. Thus, long-term outcomes should be evaluated for term-born infants who were exposed to antenatal corticosteroids in utero. OBJECTIVE: This study aimed to compare long-term outcomes between term-born children aged ≥5 years who were born to women who received antenatal corticosteroids for threatened preterm labor and children whose mothers were also evaluated for threatened preterm labor but did not receive antenatal corticosteroids. STUDY DESIGN: We performed a retrospective cohort study of children born at ≥37 weeks' gestation, aged ≥5 years, and born to mothers diagnosed with threatened preterm labor during pregnancy. The primary exposure of interest was receiving antenatal corticosteroids. Among the collected childhood medical conditions, the primary outcome of interest was a diagnosis of asthma. RESULTS: Of the 3556 term-born children aged ≥5 years, 629 (17.6%) were exposed to antenatal corticosteroids (all betamethasone), and 2927 (82.3%) were controls whose mothers were evaluated for threatened preterm birth but did not get antenatal corticosteroid injections. Women receiving antenatal corticosteroids had higher rates of maternal comorbidities (diabetes mellitus, hypertension; P≤.01). Antenatal corticosteroid-exposed children had no difference in diagnosis of asthma (12.6% vs 11.6%), attention deficit disorder, or developmental delay (P=.47, .54, and .10, respectively). Controlling for maternal and neonatal characteristics, asthma was not different between those exposed to antenatal corticosteroids and controls (odds ratio, 1.05; 95% confidence interval, 0.79-1.39). The odds of the child's weight percentile being <10% were increased for antenatal corticosteroid-exposed children born at term (odds ratio, 2.00; 95% confidence interval, 1.22-3.25). CONCLUSION: Children born at term who were exposed to antenatal corticosteroids may have increased odds of being in a lower growth percentile than those not exposed. However, rates of diagnoses such as asthma, developmental delay, and attention deficit disorders were not different.

Forced expiratory flows and diffusion capacity in infants born from mothers with pre-eclampsia.

RATIONALE: Animal models suggest pre-eclampsia (Pre-E) affects alveolar development, but data from humans are lacking. OBJECTIVE: Assess the impact of Pre-E on airway function, diffusion capacity, and respiratory morbidity in preterm and term infants born from mothers with Pre-E. METHODS: Infants born from mothers with and without Pre-E were recruited for this study; term and preterm infants were included in both cohorts. Respiratory morbidity in the first 12 months of life was assessed through monthly phone surveys. Raised volume rapid thoracoabdominal compression and measurement of diffusion capacity of the lung to carbon monoxide (DLCO) were performed at 6 months corrected age. MEASUREMENTS AND MAIN RESULTS: There were 146 infants in the Pre-E cohort and 143 in the control cohort. The Pre-E cohort was further divided into nonsevere (N = 41) and severe (N = 105) groups. There was no significant difference in DLCO and DLCO/alveolar volume among the three groups. Forced vital capacity was similar among the three groups, but the nonsevere Pre-E group had significantly higher forced expiratory flows than the other two groups. After adjusting for multiple covariates including prematurity, the severe Pre-E group had a lower risk for wheezing in the first year of life compared to the other two groups. CONCLUSIONS: Pre-E is not associated with reduced DLCO, lower forced expiratory flows, or increased wheezing in the first year of life. These results differ from animal models and highlight the complex relationships between Pre-E and lung function and respiratory morbidity in human infants.

An IL-9-pulmonary macrophage axis defines the allergic lung inflammatory environment.

Despite IL-9 functioning as a pleiotropic cytokine in mucosal environments, the IL-9-responsive cell repertoire is still not well defined. Here, we found that IL-9 mediates proallergic activities in the lungs by targeting lung macrophages. IL-9 inhibits alveolar macrophage expansion and promotes recruitment of monocytes that develop into CD11c+ and CD11c- interstitial macrophage populations. Interstitial macrophages were required for IL-9-dependent allergic responses. Mechanistically, IL-9 affected the function of lung macrophages by inducing Arg1 activity. Compared with Arg1-deficient lung macrophages, Arg1-expressing macrophages expressed greater amounts of CCL5. Adoptive transfer of Arg1+ lung macrophages but not Arg1- lung macrophages promoted allergic inflammation that Il9r-/- mice were protected against. In parallel, the elevated expression of IL-9, IL-9R, Arg1, and CCL5 was correlated with disease in patients with asthma. Thus, our study uncovers an IL-9/macrophage/Arg1 axis as a potential therapeutic target for allergic airway inflammation.

Impact of vitamin C supplementation on placental DNA methylation changes related to maternal smoking: association with gene expression and respiratory outcomes.

BACKGROUND: Maternal smoking during pregnancy (MSDP) affects development of multiple organ systems including the placenta, lung, brain, and vasculature. In particular, children exposed to MSDP show lifelong deficits in pulmonary function and increased risk of asthma and wheeze. Our laboratory has previously shown that vitamin C supplementation during pregnancy prevents some of the adverse effects of MSDP on offspring respiratory outcomes. Epigenetic modifications, including DNA methylation (DNAm), are a likely link between in utero exposures and adverse health outcomes, and MSDP has previously been associated with DNAm changes in blood, placenta, and buccal epithelium. Analysis of placental DNAm may reveal critical targets of MSDP and vitamin C relevant to respiratory health outcomes. RESULTS: DNAm was measured in placentas obtained from 72 smokers enrolled in the VCSIP RCT: NCT03203603 (37 supplemented with vitamin C, 35 with placebo) and 24 never-smokers for reference. Methylation at one CpG, cg20790161, reached Bonferroni significance and was hypomethylated in vitamin C supplemented smokers versus placebo. Analysis of spatially related CpGs identified 93 candidate differentially methylated regions (DMRs) between treatment groups, including loci known to be associated with lung function, oxidative stress, fetal development and growth, and angiogenesis. Overlap of nominally significant differentially methylated CpGs (DMCs) in never-smokers versus placebo with nominally significant DMCs in vitamin C versus placebo identified 9059 candidate "restored CpGs" for association with placental transcript expression and respiratory outcomes. Methylation at 274 restored candidate CpG sites was associated with expression of 259 genes (FDR < 0.05). We further identified candidate CpGs associated with infant lung function (34 CpGs) and composite wheeze (1 CpG) at 12 months of age (FDR < 0.05). Increased methylation in the DIP2C, APOH/PRKCA, and additional candidate gene regions was associated with improved lung function and decreased wheeze in offspring of vitamin C-treated smokers. CONCLUSIONS: Vitamin C supplementation to pregnant smokers ameliorates changes associated with maternal smoking in placental DNA methylation and gene expression in pathways potentially linked to improved placental function and offspring respiratory health. Further work is necessary to validate candidate loci and elucidate the causal pathway between placental methylation changes and outcomes of offspring exposed to MSDP. Clinical trial registration ClinicalTrials.gov, NCT01723696. Registered November 6, 2012. https://clinicaltrials.gov/ct2/show/record/NCT01723696 .

Decision tree-based rules outperform risk scores for childhood asthma prognosis.

BACKGROUND: There are no widely accepted prognostic tools for childhood asthma; this is in part due to the multifactorial and time-dependent nature of mechanisms and risk factors that contribute to asthma development. Our study objective was to develop and evaluate the prognostic performance of conditional inference decision tree-based rules using the Pediatric Asthma Risk Score (PARS) predictors as an alternative to the existing logistic regression-based risk score for childhood asthma prediction at 7 years in a high-risk population. METHODS: The Canadian Asthma Primary Prevention Study data were used to develop, compare, and contrast the prognostic performance (area under the curve [AUC], sensitivity, and specificity) of conditional inference tree-based decision rules to the pediatric asthma risk score for the prediction of childhood asthma at 7 years. RESULTS: Conditional inference decision tree-based rules have higher prognostic performance (AUC: 0.85; 95% CI: 0.81, 0.88; sensitivity = 47%; specificity = 93%) than the pediatric asthma risk score at an optimal cutoff of ≥6 (AUC: 0.71; 95% CI: 0.67, 0.76; sensitivity = 60%; specificity = 74%). Moreover, the pediatric asthma risk score is not linearly related to asthma risk, and at any given pediatric asthma risk score value, different combinations of its pediatric asthma risk score clinical variables differentially predict asthma risk. CONCLUSION: Conditional inference tree-based decision rules could be a useful childhood asthma prognostic tool, providing an alternative way to identify unique subgroups of at-risk children, and insights into associations and effect mechanisms that are suggestive of appropriate tailored preventive interventions. However, the feasibility and effectiveness of such decision rules in clinical practice is warranted.

Are newborn outcomes different for term babies who were exposed to antenatal corticosteroids?

BACKGROUND: Antenatal corticosteroids improve newborn outcomes for preterm infants. However, predicting which women presenting for threatened preterm labor will have preterm infants is inaccurate, and many women receive antenatal corticosteroids but then go on to deliver at term. OBJECTIVE: This study aimed to compare the short-term outcomes of infants born at term to women who received betamethasone for threatened preterm labor with infants who were not exposed to betamethasone in utero. STUDY DESIGN: We performed a retrospective cohort study of infants born at or after 37 weeks' gestational age to mothers diagnosed as having threatened preterm labor during pregnancy. The primary neonatal outcomes of interest included transient tachypnea of the newborn, neonatal intensive care unit admission, and small for gestational age and were evaluated for their association with betamethasone exposure while adjusting for covariates using multiple logistic regression. RESULTS: Of 5330 women, 1459 women (27.5%) received betamethasone at a mean gestational age of 32.2±3.3 weeks. The mean age of women was 27±5.9 years and the mean gestational age at delivery was 38.9±1.1 weeks. Women receiving betamethasone had higher rates of maternal comorbidities (P<.001 for diabetes mellitus, asthma, and hypertensive disorder) and were more likely to self-identify as White (P=.022). Betamethasone-exposed neonates had increased rates of transient tachypnea of the newborn, neonatal intensive care unit admission, small for gestational age, hyperbilirubinemia, and hypoglycemia (all, P<.05). Controlling for maternal characteristics and gestational age at delivery, betamethasone exposure was not associated with a diagnosis of transient tachypnea of the newborn (adjusted odds ratio, 1.10; 95% confidence interval, 0.80-1.51), although it was associated with more neonatal intensive care unit admissions (adjusted odds ratio, 1.49; 95% confidence interval, 1.19-1.86) and higher odds of the baby being small for gestational age (adjusted odds ratio, 1.78; 95% confidence interval, 1.48-2.14). CONCLUSION: Compared with women evaluated for preterm labor who did not receive betamethasone, women receiving betamethasone had infants with higher rates of neonatal intensive care unit admission and small for gestational age. Although the benefits of betamethasone to infants born preterm are clear, there may be negative impacts for infants delivered at term.

Predictive biomarker modeling of pediatric atopic dermatitis severity based on longitudinal serum collection.

The pathogenesis of atopic dermatitis (AD) results from complex interactions between environmental factors, barrier defects, and immune dysregulation resulting in systemic inflammation. Therefore, we sought to characterize circulating inflammatory profiles in pediatric AD patients and identify potential signaling nodes which drive disease heterogeneity and progression. We analyzed a sample set of 87 infants that were at high risk for atopic disease based on atopic dermatitis diagnoses. Clinical parameters, serum, and peripheral blood mononuclear cells (PBMCs) were collected upon entry, and at one and four years later. Within patient serum, 126 unique analytes were measured using a combination of multiplex platforms and ultrasensitive immunoassays. We assessed the correlation of inflammatory analytes with AD severity (SCORAD). Key biomarkers, such as IL-13 (rmcorr=0.47) and TARC/CCL17 (rmcorr=0.37), among other inflammatory signals, significantly correlated with SCORAD across all timepoints in the study. Flow cytometry and pathway analysis of these analytes implies that CD4 T cell involvement in type 2 immune responses were enhanced at the earliest time point (year 1) relative to the end of study collection (year 5). Importantly, forward selection modeling identified 18 analytes in infant serum at study entry which could be used to predict change in SCORAD four years later. We have identified a pediatric AD biomarker signature linked to disease severity which will have predictive value in determining AD persistence in youth and provide utility in defining core systemic inflammatory signals linked to pathogenesis of atopic disease.

STAT5 promotes accessibility and is required for BATF-mediated plasticity at the Il9 locus.

T helper cell differentiation requires lineage-defining transcription factors and factors that have shared expression among multiple subsets. BATF is required for development of multiple Th subsets but functions in a lineage-specific manner. BATF is required for IL-9 production in Th9 cells but in contrast to its function as a pioneer factor in Th17 cells, BATF is neither sufficient nor required for accessibility at the Il9 locus. Here we show that STAT5 is the earliest factor binding and remodeling the Il9 locus to allow BATF binding in both mouse and human Th9 cultures. The ability of STAT5 to mediate accessibility for BATF is observed in other Th lineages and allows acquisition of the IL-9-secreting phenotype. STAT5 and BATF convert Th17 cells into cells that mediate IL-9-dependent effects in allergic airway inflammation and anti-tumor immunity. Thus, BATF requires the STAT5 signal to mediate plasticity at the Il9 locus.

Antenatal corticosteriods decrease forced vital capacity in infants born fullterm.

Antenatal corticosteroids (ACS) administration to pregnant women for threatened preterm labor is standard obstetric care to reduce neonatal respiratory distress syndrome and the associated respiratory morbidity. While ACS stimulates surfactant production in the fetal lung, the effects of ACS upon the subsequent growth and development of the lung are unclear. Follow-up studies outside of the neonatal period have been primarily limited to spirometry, and most subjects evaluated were born prematurely. To our knowledge, no study has assessed both airway and parenchymal function in infants or adults following ACS exposure. We hypothesized that ACS impairs lung growth and performed infant pulmonary function testing, which included spirometry, alveolar volume (VA ) and lung diffusion (DL ). As a pilot study, we limited our assessment to infants whose mothers received ACS for threatened preterm labor, but then proceeded to full term delivery. This approach evaluated a more homogenous population and eliminated the confounding effects of preterm birth. We evaluated 36 full-term infants between 4 to 12 months of age; 17 infants had ACS exposure and 19 infants had no ACS exposure. Infants exposed to ACS had a significantly lower forced vital capacity compared with non-ACS exposed infants (250 vs 313 mL; P = .0075). FEV0.5 tended to be lower for the ACS exposed group (205 vs 237 mL; P = .075). VA and DL did not differ between the two groups. These findings suggest that ACS may impair subsequent growth of the lung parenchyma.

Vitamin C to Pregnant Smokers Persistently Improves Infant Airway Function to 12†Months of Age: A Randomised Trial.

BACKGROUND: Vitamin C (500 mg·day-1) supplementation for pregnant smokers has been reported to increase newborn pulmonary function and infant forced expiratory flows (FEFs) at 3 months of age. Its effect on airway function through 12 months of age has not been reported. OBJECTIVE: To assess whether vitamin C supplementation to pregnant smokers is associated with a sustained increased airway function in their infants through 12 months of age. METHODS: This is a prespecified secondary outcome of a randomised, double-blind, placebo-controlled trial that randomised 251 pregnant smokers between 13 and 23 weeks of gestation: 125 to 500 mg·day-1 vitamin C and 126 to placebo. Smoking cessation counselling was provided. FEFs performed at 3 and 12 months of age were analysed by repeated measures analysis of covariance. RESULTS: FEFs were performed in 222 infants at 3 months and 202 infants at 12 months of age. The infants allocated to vitamin C had significantly increased FEFs over the first year of life compared to those allocated to placebo. The overall increased flows were: 40.2 mL·sec-1 for FEF75 (adjusted 95% CI for difference 6.6 to 73.8; p=0.025); 58.3 mL·sec-1 for FEF50 (95% CI 10.9 to 105.8; p=0.0081); and 55.1 mL·sec-1 for FEF25-75 (95% CI, 9.7 to 100.5; p=0.013). CONCLUSIONS: In offspring of pregnant smokers randomised to vitamin C versus placebo, vitamin C during pregnancy was associated with a small but significantly increased airway function at 3 and 12 months of age, suggesting a potential shift to a higher airway function trajectory curve. Continued follow-up is underway.