Prenatal nicotine exposure affects cardiovascular function and growth of the developing fetus

Association of secondhand smoke exposure during pregnancy with left ventricle structure and function in offspring at 4 years old: a prospective birth cohort study

BACKGROUND

The association of secondhand smoke exposure during pregnancy with childhood cardiac alterations remains insufficiently elucidated. This study aims to explore the correlation between maternal passive smoking during gestation with cardiac structure and function of offspring.

METHODS

1089 mother-offspring pairs from the Shanghai Birth Cohort were included. Information on secondhand smoke exposure during each trimester of pregnancy and baseline characteristics was documented during pregnancy via structured questionnaire. Subsequent follow-up assessments, encompassing anthropometric information and echocardiographic evaluation, were conducted from 2018 to 2021, when the children were 4 years old. Multiple linear regressions models were used to explore the association of secondhand smoke exposure during pregnancy with left ventricular measurements in early childhood.

RESULTS

Secondhand smoke exposure during pregnancy was correlated with increased left ventricle (LV) internal diameter in diastole [LVIDd; β = 0.38, 95%CI: (0.06, 0.70)] and in systole [LVIDs; β = 0.28, 95%CI: (0.02, 0.54)] adjusted for maternal and child characteristics. Specifically, maternal passive smoking in early pregnancy (≤ 12 weeks of gestation) showed a positive association with LV internal diameter in diastole [LVIDd; β = 0.46, 95%CI: (0.14, 0.79)], in systole [LVIDs; β = 0.35, 95%CI: (0.09, 0.60)], end diastolic volume [LVEDV; β = 1.45, 95%CI: (0.26, 2.63)] and end systolic volume [LVESV; β = 0.68, 95%CI: (0.18, 1.19)]. No significant association was observed between secondhand smoke exposure during pregnancy and LV function of offspring.

CONCLUSION

Secondhand smoke exposure during pregnancy was correlated with subclinical alterations in LV dimensions of offspring, especially during the early stage of pregnancy. Further research is necessary to confirm our findings and to explore the long-term effect of these cardiac changes on later cardiovascular risks.

The Relationship between Maternal Smoking and Infant Birth Weight: Improving Accuracy through Urine Cotinine Analysis and Effective Medical Record Strategies

OBJECTIVE

We conducted a study to determine if antenatally collected maternal urine cotinine (a metabolite of nicotine) measurements can be used to assess the neonatal impact of nicotine exposure during pregnancy. This was a prospective longitudinal cohort of mother-infant dyads. Only term singleton pregnancies were included. The primary outcome measure was the correlation between maternal urine cotinine and infant birth weight.

METHODS

We analysed data from 238 mother-neonate dyads. Smoking habits were recorded during routine prenatal check-ups and urine samples were collected to measure cotinine and creatinine levels.

RESULTS

Urine cotinine was detected in 50.4% (120/238) of women from the whole cohort, but only 16% (38/238) self-reported as smokers (chi-square 39.7, p < 0.0001), and these women had significantly smaller babies (p = 0.010). There was a significant negative correlation between maternal urine cotinine and birth weight (Spearman's coefficient = -0.0226, p = 0.013). Female babies born to women with nicotine in their urine were significantly smaller (p = 0.001).

CONCLUSIONS

Infant birth weight significantly reduced in mothers with exposure to nicotine during pregnancy. The number of women exposed to nicotine during late pregnancy (measured in urine) was markedly higher than self-reported and national smoking percentages, suggesting an urgent need for an improvement in medical record reporting on smoking habits to better assess neonatal outcomes.

Evidence for Wnt signaling's central involvement in perinatal nicotine exposure-induced offspring lung pathology and its modulation by electroacupuncture

OBJECTIVE

Many factors during pregnancy can induce intrauterine growth restriction (IUGR), resulting in various adverse perinatal outcomes such as low birth weight and multiple organ disorders. Among these factors, prenatal smoke/nicotine exposure is a common cause of IUGR, often associated with altered fetal lung development. The classical Wnt signaling pathway plays a vital role in lung development, and its alterations are commonly associated with developmental lung pathologies. The purpose of this study was to determine whether electroacupuncture (EA) at "Zusanli" (ST 36) points protects perinatal nicotine exposure (PNE)-induced offspring lung dysplasia through Wnt/β-catenin signaling pathway and to identify specific Wnt signaling pathway targets of EA.

METHODS

Following a well-established protocol, nicotine (1 mg/kg/ body weight) was administered subcutaneously to pregnant Sprague Dawley rat dams from gestational day 6 to postnatal day 21. In the EA group, dams were treated with EA at both ST 36 acupoints, while in another experimental group, Wnt/β-catenin signaling pathway agonist was injected subcutaneously (2 mg/kg/ body weight). Offspring body weight (PND 1, 7, 14, and 21), lung weight, Wnt signaling markers, pulmonary function, and lung morphology were determined at sacrifice on PND 21. Specifically, Western blotting and Real-time PCR were used to detect the protein and mRNA levels of critical Wnt signaling markers Wnt2, Wnt7b, FZD4, FZD7, LRP5, and LRP6 in the offspring lung. The protein levels of β-catenin in lung tissue of offspring rats were detected by ELISA that of LEF-1 by Western blotting.

RESULTS

Compared to the control group, the body and lung weights of the offspring rats were significantly decreased in the nicotine-only exposed group. The pulmonary function determined as FVC, PEF, TV, and Cdyn was also significantly decreased, while PIF was significantly increased. The protein levels and mRNA expression of Wnt2, Wnt7b, FZD4, FZD7, LRP5, and LRP6 in the lung tissue of the PNE offspring rats were significantly increased. With EA administration at ST 36 acupoints concomitant with nicotine administration, the body and lung weights, pulmonary function (FVC, PEF, PIF, TV, and Cdyn), protein and mRNA levels Wnt signaling pathway markers (Wnt2, Wnt7b, FZD4, FZD7, LRP5, LRP6, β-catenin, and LEF-1) normalized and were not different from the control group. Notably, Wnt agonists agonist administration blocked the protective effects of EA against PNE-induced lung morphological, molecular, and function changes, highlighting the central significance of Wnt pathway signaling in PNE-induced offspring pulmonary pathology and its modulation by EA at ST 36 acupoints.

CONCLUSION

Concomitant maternal EA at ST 36 acupoints from gestational day 6 to PND 21 protects against offspring PNE-induced lung phenotype. The protective effect is achieved by regulating the expression of Wnt ligand proteins (Wnt2 and Wnt7b) and receptor proteins (FZD4, FZD7, LRP5, and LRP6) upstream of the Wnt/β-catenin signaling pathway intermediates β-catenin, and LEF-1.

The impact of smoking and nicotine exposure during pregnancy on fetal nephrogenesis: a systematic review

The effect of smoking and nicotine exposure during pregnancy on fetal nephrogenesis is a growing area of research. The objective of this systematic review is to summarise the current evidence in this research field. Our literature search identified a total of 415 articles from PubMed, Embase, Scopus, and Cochrane. After electronic sorting and manual screening, 18 eligible articles were found, 6 being human studies and 12 being animal studies. Articles that did not study nicotine or smoking, did not focus on fetal kidney development, or did not include nicotine or smoking exposure during pregnancy were excluded from the systematic review. The main outcomes of the studies were kidney weight, volume and size, kidney histopathology and morphology, and kidney function. Evidence from human studies identified a reduction in fetal kidney size, volume, and weight in offspring exposed to smoking during pregnancy; and the greatest impact was seen in offspring exposed to >5-10 cigarettes per day. Animal studies investigated kidney histopathology and highlighted kidney injury and microscopic changes in response to nicotine exposure during pregnancy. Further research is required to determine the impact on kidney function. Recreational nicotine use is evolving, and with the increasing use of urine cotinine in the evaluation of nicotine exposure, further research is needed.

The Regulatory Role of H19/miR-181a/ATG5 Signaling in Perinatal Nicotine Exposure-Induced Development of Neonatal Brain Hypoxic-Ischemic Sensitive Phenotype

Nicotine exposure either from maternal cigarette smoking or e-cigarette vaping is one of the most common risk factors for neurodevelopmental disease in offspring. Previous studies revealed that perinatal nicotine exposure programs a sensitive phenotype to neonatal hypoxic-ischemic encephalopathy (HIE) in postnatal life, yet the underlying mechanisms remain undetermined. The goal of the present study was to determine the regulatory role of H19/miR-181a/ATG5 signaling in perinatal nicotine exposure-induced development of neonatal brain hypoxic-ischemic sensitive phenotype. Nicotine was administered to pregnant rats via subcutaneous osmotic minipumps. All experiments were conducted in offspring pups at postnatal day 9 (P9). Perinatal nicotine exposure significantly enhanced expression of miR-181a but attenuated autophagy-related protein 5 (ATG5) mRNA and protein levels in neonatal brains. Of interest, miR-181a mimicking administration in the absence of nicotine exposure also produced dose-dependent increased hypoxia/ischemia (H/I)-induced brain injury associated with a decreased ATG5 expression, closely resembling perinatal nicotine exposure-mediated effects. Locked nucleic acid (LNA)-miR-181a antisense reversed perinatal nicotine-mediated increase in H/I-induced brain injury and normalized aberrant ATG5 expression. In addition, nicotine exposure attenuated a long non-coding RNA (lncRNA) H19 expression level. Knockdown of H19 via siRNA increased the miR-181a level and enhanced H/I-induced neonatal brain injury. In conclusion, the present findings provide a novel mechanism that aberrant alteration of the H19/miR-181a/AGT5 axis plays a vital role in perinatal nicotine exposure-mediated ischemia-sensitive phenotype in offspring and suggests promising molecular targets for intervention and rescuing nicotine-induced adverse programming effects in offspring.

Unique effects of nicotine across the lifespan

Smoking remains the leading cause of preventable death in the United States. Although combustible cigarettes are largely being replaced by tobacco-free products, nicotine use continues to increase in vulnerable populations, including youth, adolescents, and pregnant women. Nicotine exerts unique effects on specific brain regions during distinct developmental periods due to the dynamic expression of nicotinic acetylcholine receptors (nAChRs) throughout the lifespan. Nicotine exposure is a health concern not only for adults but also has neurotoxic effects on the fetus, newborn, child, and adolescent. In this review, we aim to highlight the dynamic roles of nAChRs throughout gestation, adolescence, and adulthood. We also provide clinical and preclinical evidence of the neurodevelopmental, cognitive, and behavioral consequences of nicotine exposure at different developmental periods. This comprehensive review highlights unique effects of nicotine throughout the lifespan to help elucidate interventions and public health measures to protect sensitive populations from nicotine exposure.