Developmental toxicity of e‐cigarette aerosols

Abstract

Maternal smoking during pregnancy represents a major public health concern increasing the risk for low birth weight, congenital anomalies, preterm birth, fetal mortality, and morbidity. In an effort to diminish adverse developmental effects of exposure to cigarette smoking, pregnant women, and women of reproductive age, are increasingly turning to electronic nicotine delivery systems (ENDS), such as e‐cigarettes, as an alternative. Given that health risks associated with ENDS use during pregnancy are largely unknown, there is an acute need to determine risks vs. benefits of e‐cigarette use by pregnant women. While the most recent Surgeon General's Report on the “Health Consequences of Smoking” states that “the evidence is sufficient to infer that nicotine adversely affects maternal and fetal health during pregnancy, contributing to multiple adverse outcomes,” it remains unclear whether use of ENDS represents a “safer alternative” to tobacco smoking during pregnancy. This is due, in part, to the lack of sufficient and conclusive evidence concerning whether or not maternal e‐cigarette use adversely affects embryonic/fetal development. While several recent developmental studies have challenged the safety of nicotine inhalation via ENDS, the true risks of smoking e‐cigarettes during the first trimester of pregnancy—the period of organogenesis—are largely unknown. Moreover, evidence is emerging that even nicotine‐free e‐cigarette aerosols may harm the developing conceptus, suggesting that components of e‐cigarette liquid, including flavorings, may be developmentally toxicity. Focused human epidemiological analyses, and carefully designed animal studies are critically needed to address the question of the safety of ENDS use during pregnancy.

The role of teratogens in neural crest development

“…However, the placental and fetal alterations following the ENDS aerosol exposure compared to cigarette smoke exposure are still lacking. Taking into account that the fetal health risk of ENDS use during pregnancy is unknown, a need exists to establish the effects on NC development of e‐cigarettes use by pregnant women (Greene & Pisano, ).…”

The use of human induced pluripotent stem cells to screen for developmental toxicity potential indicates reduced potential for non-combusted products, when compared to cigarettes

“…The Centers for Disease Control and Prevention (CDC) and US Surgeon General state that cigarette smoking harms every phase of reproduction ( CDC, 2004 , US Department of Health Human Services, 2014 ). The impact of cigarette smoking on pregnancy has been reported in published scientific literature and by public health bodies ( CDC, 2004 , RCP, 2010 ), with maternal smoking during pregnancy being described in one review as ‘ perhaps the single most avoidable cause of adverse pregnancy outcomes’ ( Greene and Pisano, 2019 ). The reported adverse effects of cigarette smoking during pregnancy include an increased risk of: low birth weight, underdeveloped organs, congenital abnormalities, preterm birth, and foetal mortality ( Greene and Pisano, 2019 ).…”

MicroRNAs as Epigenetic Targets of Cigarette Smoke During Embryonic Development

“…This notion is based on the assumption that e-cigs produce aerosols that are devoid of many of the chemicals present in CS. Nevertheless, there is no conclusive evidence to suggest that maternal e-cig use does not affect normal embryonic and fetal development [ 28 ]. These aerosols contain chemicals, such as formaldehyde and acrolein, which can cause DNA damage and mutagenesis.…”

“…These aerosols contain chemicals, such as formaldehyde and acrolein, which can cause DNA damage and mutagenesis. Indeed, recent evidence indicates that exposure to these aerosols results in increased oxidative stress in laboratory animals and humans, cardiac defects in zebrafish larvae and craniofacial defects in frog embryos [ 28 , 29 ]. Several e-cig products have also been found to be contaminated with microbial toxins [ 30 ].…”