Study links e-cigarette vanillin flavoring to embryonic development disruption

RIVERSIDE, California — Researchers at the University of California, Riverside, have found that vanillin, a flavoring widely used in high concentrations in e-cigarettes, can cause serious developmental abnormalities in human embryonic cells. Because clinical trials on pregnant women are prohibited on ethical grounds, the study was conducted on human embryonic stem cells that mimic the third week of pregnancy. The findings, published in the journal Human Reproduction, showed that exposure to micromolar levels of vanillin triggered cell death, while nanomolar levels led to a loss of the ability to differentiate into various cell types. The research team determined that vanillin binds to the TRPV4 protein found on embryonic cell membranes, and that the harmful effects disappeared when this protein was disabled in the laboratory. Study leader Prue Talbot said the changes observed could prevent the healthy development of the embryo. The researchers emphasized that the experimental results do not necessarily mean the same effects would occur in the human body at similar concentrations, but said the study offers a possible mechanism that could help explain the link between e-cigarette use and difficulty conceiving or miscarriage risk.