Study: Vanillin, a Common Vape Flavor, May Disrupt Early Embryonic Development

Vanillin, a flavoring chemical widely used in e-cigarettes, may interfere with early embryonic development, according to laboratory research published August 12 in the journal Human Reproduction. The findings offer a possible biological explanation for previously reported links between vaping, difficulty conceiving, and miscarriage.

Because testing vape chemicals directly in pregnant women or developing embryos would be impractical and unethical, researchers led by Prue Talbot at the University of California, Riverside, exposed human embryonic stem cells, which resemble cells found in human embryos at about three weeks of development, to different concentrations of vanillin in the lab. Micromolar concentrations, representing higher exposure, tended to kill the cells. Nanomolar concentrations, representing lower exposure, caused cells to lose pluripotency, the ability to develop into any cell type, and to differentiate into endoderm rather than the normal mix of endoderm, ectoderm and mesoderm. Endoderm gives rise to the lining of the gut and respiratory tissues; without ectoderm, the nervous system fails to develop, and without mesoderm, tissues such as muscle fail to develop.

The researchers traced the effect to TRPV4, a channel on the surface of embryonic stem cells. Vanillin binds to TRPV4, triggering an influx of calcium, a signaling molecule that activates the downstream changes in pluripotency and cell fate. When the researchers blocked TRPV4 with a chemical antagonist or an antibody, vanillin no longer produced these effects, confirming the channel's role.

"Our data predict that nanomolar concentrations of vanillin may reach the embryo in pregnant women who vape," said Talbot, who recommended that physicians advise against vaping during pregnancy, particularly for women having trouble conceiving or experiencing miscarriages, and that regulators consider mandatory ingredient disclosure on e-cigarette packaging.