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BackgroundMaternal cigarette smoking during pregnancy (MSDP) is associated with numerous adverse health outcomes in infants and children with potential lifelong consequences. Negative effects of MSDP on placental DNA methylation (DNAm), placental structure, and function are well established.ObjectiveOur aim was to develop biomarkers of MSDP using DNAm measured in placentas (N=96), collected as part of the Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function double-blind, placebo-controlled randomized clinical trial conducted between 2012 and 2016. We also aimed to develop a digital polymerase chain reaction (PCR) assay for the top ranking cytosine-guanine dinucleotide (CpG) so that large numbers of samples can be screened for exposure at low cost.MethodsWe compared the ability of four machine learning methods [logistic least absolute shrinkage and selection operator (LASSO) regression, logistic elastic net regression, random forest, and gradient boosting machine] to classify MSDP based on placental DNAm signatures. We developed separate models using the complete EPIC array dataset and on the subset of probes also found on the 450K array so that models exist for both platforms. For comparison, we developed a model using CpGs previously associated with MSDP in placenta. For each final model, we used model coefficients and normalized beta values to calculate placental smoking index (PSI) scores for each sample. Final models were validated in two external datasets: the Extremely Low Gestational Age Newborn observational study, N=426; and the Rhode Island Children's Health Study, N=237.ResultsLogistic LASSO regression demonstrated the highest performance in cross-validation testing with the lowest number of input CpGs. Accuracy was greatest in external datasets when using models developed for the same platform. PSI scores in smokers only (n=72) were moderately correlated with maternal plasma cotinine levels. One CpG (cg27402634), with the largest coefficient in two models, was measured accurately by digital PCR compared with measurement by EPIC array (R2=0.98).DiscussionTo our knowledge, we have developed the first placental DNAm-based biomarkers of MSDP with broad utility to studies of prenatal disease origins. https://doi.org/10.1289/EHP13838.

Delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis, remains a schedule I substance, thus safety data regarding the effects on the cardiovascular and prenatal health are limited. Importantly, there is evidence showing prenatal cannabis exposure can negatively impact fetal organ development, including the cardiovascular system. THC can cross the placenta and bind to cannabinoid receptors expressed in the developing fetus, including on endothelial cells. To understand the impact of prenatal THC exposure on the fetal cardiovascular system, we used our rhesus macaque model of prenatal daily edible THC consumption. Before conception, animals were acclimated to THC (2.5 mg/7 kg/day, equivalent to a heavy medical cannabis dose) and maintained on this dose daily throughout pregnancy. Fetal tissue samples were collected at gestational day 155 (full term is 168 days). Our model showed that in utero THC exposure was associated with a decreased heart weight-to-body weight ratio in offspring, warranting further mechanistic investigation. Histological examination of the fetal cardiac and vascular tissues did not reveal any significant effect of THC exposure on the maturity of collagen within the fetal heart or the aorta. Total collagen III expression and elastin production and organization were unchanged. However, bulk RNA-sequencing of vascular cells in the umbilical vein, umbilical artery, and fetal aorta demonstrated that THC alters the fetal vascular transcriptome and is associated with upregulated expression of genes involved in carbohydrate metabolism and inflammation. The long-term consequences of these findings are unknown but suggest that prenatal THC exposure may affect cardiovascular development in offspring. NEW & NOTEWORTHY: Prenatal cannabis use is increasing and despite the public health relevance, there is limited safety data regarding its impact on offspring cardiovascular health outcomes. We used a translational, nonhuman primate model of daily edible Δ-9-tetrahydrocannabinol (THC) consumption during pregnancy to assess its effects on the fetal cardiovascular system. THC-exposed fetal vascular tissues displayed upregulation of genes involved in cellular metabolism and inflammation, suggesting that prenatal THC exposure may impact fetal vascular tissues. [ABSTRACT FROM AUTHOR]

Prenatal cannabis use is rising, in part due to legalization and perceptions of safety. The impact of prenatal cannabis exposure on offspring development, especially respiratory health, remains largely unknown. The objective of this study was to determine whether in utero exposure to delta-9-tetrahydrocannabinol (THC), the main psychoactive component of cannabis, is deleterious to offspring lung development and function using a rhesus macaque model. Female rhesus macaques received a daily edible containing either THC (2.5 mg/7 kg/day, equivalent to a heavy medical cannabis dose) or placebo during gestation and postnatally. Serial in utero magnetic resonance imaging (MRI) was performed during pregnancy at approximately gestational days (G)110 and G150. At 6 mo of age, infants underwent pulmonary function testing, followed by tissue collection for molecular analysis (bulk RNAseq, whole genome bisulfite sequencing, and spatial RNAseq). THC-exposed infants displayed significantly reduced forced residual capacity, which correlated with nonsignificant decreases in total lung capacity, lung diffusion capacity and lower fetal lung perfusion, oxygen availability, and lung volume measured by MRI. Consistent with these decreases in volume indices, levels of pulmonary growth factors were decreased in bronchial alveolar lavage at 6 mo. Molecular analysis of infant lungs revealed altered epigenetic regulation of gene expression, including at genes involved in extracellular matrix organization and lung development, and activation of immune signaling. Our study suggests that exposure to prenatal edible THC alters epigenetic regulation of lung gene expression and may negatively affect offspring lung development and function. Data from this study will help guide healthcare provider counseling on cannabis use in pregnancy. NEW & NOTEWORTHY In a translational rhesus macaque model, chronic prenatal delta-9-tetrahydrocannabinol exposure resulted in decreased lung volumes in offspring measured at 6 mo of age. These decreases correlated with altered DNA methylation in the lung, including at genes involved in extracellular matrix organization, lung development, and activation of immune signaling, and changes in lung cell composition as measured by spatial transcriptomics. These findings add to the growing evidence that prenatal cannabis exposure may adversely affect offspring development.

Rationale: Most premature human infants are born in the moderate to late preterm (MLP) range, ≥30 to <37 weeks gestation and demonstrate increased incidence of wheeze and respiratory illness as they age. Animal models suggest that mechanical lung distention stimulates lung growth and alveolar development. To determine if nasal continuous positive airway pressure (nCPAP) influences MLP infant lung development, we developed a rhesus monkey model of moderate prematurity, randomized to 9 days of nCPAP or sham nCPAP., Methods: Timed-pregnant fetuses were delivered by elective hysterotomy at gestational age (GA) 140±1 days (85% gestation, term=165 days; human equivalent of 32-34 weeks), or at GA-149±1 days (GA-control) as a relative gestational age reference. The day after delivery, the GA-140 animals were treated with nCPAP or sham for 9 days, 12 consecutive hours each day. Pulmonary function testing followed by necropsy for analysis of lung structure and gene expression was performed on the equivalent of GA-150 for all animals., Results: The nCPAP and sham groups were clinically similar but distinct from the gestational control group. Stereological analysis of lung structure showed significantly increased numbers of alveoli in the nCPAP group compared to the sham group. Other functional and anatomic changes were consistent with increased alveolarization. Gene expression between the nCPAP and sham groups remained highly similar and distinct from GA-control animals., Conclusions: We show that nCPAP in MLP infants stimulates alveolarization with relatively few other changes. How this may benefit subsequent infant respiratory health requires further study., (Copyright ©The authors 2025. For reproduction rights and permissions contact permissions@ersnet.org.)

Background: Spirometry is the gold standard for assessing airway function for clinical studies; however, obtaining high-quality data in young children remains challenging. Since the forced oscillation technique (FOT) requires less subject cooperations, there has been increasing interest in FOT, particularly in young children. We evaluated whether spirometry and FOT in young children provides comparable ability to detect a treatment effect., Methods: We recently reported in a randomized controlled trial that vitamin C compared to placebo treatment of mothers who smoked during pregnancy (MSDP) results in the offspring having significantly higher forced expiratory flows (FEFs) at 5-years of age, as well as significantly less wheeze at 4-6 years of age. In these same offspring, we also measured respiratory impedance using FOT at 8-Hz impedance at 3, 4, and 5 years of age., Results: Although spirometry demonstrated significantly increased FEFs in vitamin C compared to placebo-treatment group at 5 years of age (p < 0.001), we were not able to detect a similar treatment effect using FOT impedance., Conclusions: It may be challenging to obtain technically successful spirometry in preschool children; however, FEFs may provide a better outcome than single-frequency FOT impedance to assess improvements in airway function in these young subjects., (© 2024 The Author(s). Pediatric Pulmonology published by Wiley Periodicals LLC.)