The impact of tobacco chemicals and nicotine on placental development

Abstract

Despite decades of messages warning about the dangers of tobacco use in pregnancy, 10% to 15% of pregnant women continue to smoke. Furthermore, an increased popularity of electronic nicotine delivery systems (ENDS) over the past decade in women of childbearing age raises parallel concerns regarding the effects of vaporized nicotine use in pregnancy. While research using animal models which mimic tobacco smoke and nicotine exposure in pregnancy have largely replicated findings in humans, few studies focus directly on the effects of these exposures on the placenta. Because the placenta is a fetal derived tissue, and nicotine and other components of tobacco smoke are either processed by or transported directly through the placenta, such studies help us understand the risks of these exposures on the developing fetus. In this review, we summarize research on the placenta and placental‐derived cells examining either tobacco smoke or nicotine exposure, including both histologic and subcellular (ie, epigenetic and molecular) modifications. Collectively, these studies reveal that tobacco and nicotine exposure are accompanied by some common and several unique molecular and epigenomic placental modifications. Consideration of the nature and sequelae of these molecular mediators of risk may help to better inform the public and more effectively curtail modifiable behavior.

Cigarette smoke induced neural tube defects by down‐regulating noggin expression

“…This will allow harmful substances to easily enter the fetus through the placental barrier, causing abnormal development of the fetus (Liu et al, 2018). Cigarette smoke exposure can impair the structure and function of trophoblast cells (Kim et al, 2017; Suter & Aagaard, 2020). Our experiments found that cigarette smoke can increase the expression of pro‐apoptotic factor BAX and the expression of KI67, a cell proliferation marker in placental tissues, suggesting that cigarette smoke can disrupt the placental development process.…”

Epigenetic Alterations of Maternal Tobacco Smoking during Pregnancy: A Narrative Review

“…Placenta collected at birth does not allow measures of DNA methylation changes through pregnancy, but as cord blood, it presents the advantage of being easy to collect after birth [ 107 ], with a high acceptability rate. Placenta also requires few ethical concerns for its use in medical research [ 105 ]. The relationship between DNA methylation in placenta and other tissues will likely vary depending on the target gene, exact location, and timing of sampling.…”

“…Most studies rely on DNA methylation, which is the best understood and the most cost-effective epigenetic mark to consider in epidemiological studies, and it is conducted on placenta, cord blood, or peripheral children’s blood. Extensive reviews have been published in the last couple of years, including specific reviews on maternal tobacco smoking during pregnancy and epigenetics [ 58 , 104 , 105 ] and more general reviews on smoking and epigenetics [ 106 , 107 , 108 ].…”

Electronic Nicotine Delivery Systems (ENDS) Use and Pregnancy II: Perinatal Outcomes Following ENDS Use During Pregnancy

“…Although most of this research excludes pregnant persons, the general risks of exposure to toxicants and organ damage would be expected to apply to pregnant persons who use ENDS as well. Moreover, there may be additional risk to the fetus as a number of these toxicants may pass through the placenta [39].…”