Stem cell research shows vape flavour could affect embryo development

Vanillin, a common flavouring used in vapes and e-cigarettes, may pose a risk to embryonic development if inhaled during pregnancy.

According to new research from the University of California, Riverside, human embryonic stem cells exposed to vanillin concentrations consistent with maternal vape use lost the ability to form all the cell types required for embryonic development.

'We focused on vanillin because it is frequently used in e-cigarette fluids, it is often used at high concentrations, and because we knew that embryonic cells had a channel called TRPV4 on their surface that would likely bind with vanillin,' said Professor Prue Talbot, who led the research published in Human Reproduction.

To model the effects of vanillin in two- to three-week-old human embryos, the team exposed human embryonic stem cells to varying levels of vanillin. High vanillin concentrations led to cell death, while exposure levels equivalent to one to four puffs per hour of a vape containing standard vanillin concentrations caused cells to lose pluripotency – the ability to develop into all cell types. They were unable to form two of the three distinct cell classes required for embryonic development.

'These changes are potentially very serious and could prevent normal development of embryos,' said first author Dr Shabnam Etemadi.

To understand how vanillin interacts with cells, the researchers also exposed the same stem cells to vanillin in combination with a TRPV4 antagonist, which prevented vanillin from binding to the receptor. These cells were unaffected by vanillin, confirming the TRPV4 channel as the route for vanillin's interaction with cells.

As this research was carried out in a laboratory using cellular models, it does not demonstrate a direct clinical link between women using e-cigarettes containing vanillin and disrupted embryo development or miscarriage. However, previous studies have found that vape use during pregnancy can increase the risk of decreased birth weight, pre-term birth, fetal growth restriction, neurological dysfunction and small size for gestational age.

'As this is research done on embryonic cells in a lab, it will need to be further clarified in human clinical trials as laboratory findings do not necessarily always translate into clinically relevant outcomes,' said Jacob George, professor of cardiovascular medicine at the University of Dundee, who was not involved in the study.

'Having said that, many researchers, including myself, have been calling for the limiting of flavours in vapes and for further research to be done on the impact of flavourings. Whilst nicotine-containing vapes are seen as a harm reduction measure compared to tobacco cigarettes, the presence of unregulated chemicals in flavourings is a concern that needs to be addressed,' he added.

Dr Etemadi and Professor Talbot previously published similar research on menthol, which is also used as a flavouring in cigarettes and vapes.