Neurological Effects in the Offspring after Switching From Tobacco Cigarettes to E-Cigarettes During Pregnancy in a Mouse Model.

Introduction:
This text presents the results of a study investigating the effects of switching from tobacco cigarettes to e-cigarettes during pregnancy on the offspring's neurological development in a mouse model. The study used maternal exposure to tobacco smoke and e-cigarette aerosols to assess litter size, plasma cotinine levels, offspring body weight, memory, exploration/activity, anxiety, global DNa methylation, epigenetic gene expression, and neuronal counts.

Key Points:

* The study found that there was no significant difference in litter size among the three groups (Sham, SE, and Switch).
* Mothers from the SE and Switch groups had significantly higher cotinine levels compared to the Sham group, indicating nicotine exposure.
* Offspring from mothers that switched to e-cigarette aerosol exposure or exposed to continuous cigarette smoke during pregnancy had a low birth weight.
* Switching to e-cigarette aerosol exposure resulted in changes in offspring memory and hyperactivity, as shown in the NOR and EPM tests.
* Offspring from the Switch group showed global DNa methylation levels lower than the SE group, indicating that switching to e-cigarettes during pregnancy reduced DNa methylation in the offspring brain.
* The study also found that switching to e-cigarette aerosol exposure altered epigenetic gene expression of representative chromatin modification enzymes, including DNa methyltransferases, histone demethylases, histone acetylase, and deacetylase.
* In the dorsal hippocampus of adult offspring, the SE group had reduced neuronal counts, but the Switch group did not, highlighting the difficulty of teasing out the effects of tobacco chemicals, nicotine, and e-fluid chemicals on neurological function at different postnatal time points.

Main Message:
The study suggests that switching from tobacco cigarettes to e-cigarettes during pregnancy does not ameliorate the change in body weight and may not be safer in terms of neurocognitive outcomes. The study also highlights the need for further investigation into the epigenetic and physiological effects of e-cigarette use during pregnancy. Therefore, abstinence from all nicotine delivery products during pregnancy should still be advised.

Nguyen T, Li GE, Chen h, Cranfield CG, McGrath KC, Gorrie Ca. Neurological Effects in the Offspring after Switching From Tobacco Cigarettes to E-Cigarettes During Pregnancy in a Mouse Model. Toxicological sciences : an official journal of the Society of Toxicology. 2019;172(1):191-200. doi:10.1093/toxsci/kfz194