To find out the effect of vaping, a research team exposed frog embryos and samples of mammalian neural crest cells to saline-infused with e-cigarette vapor.
‘Complex e-liquids that mix flavors, such as berries and creme and other food-related flavorings can damage neural crest cells that cause defects in the face.’
Vapour is created when e-liquids - blends of nicotine, propylene, glycol, vegetable glycerin and various flavoring compounds - are heated within e-cigarettes during inhalation. The vapor is then collected in a syringe before it is infused into saline.
Frogs, like other vertebrates, are similar to humans embryonically, said Amanda Dickinson, from the Virginia Commonwealth University (VCU) in the US. "This means that if a chemical perturbs a frog embryo, it's likely to do the same thing to a human embryo," said Dickinson, one of the authors of the study published in the journal PLOS
Mammalian neural crest cells are also ideal models because they have a key role in embryonic facial development. Damage to these cells in utero can cause craniofacial birth defects, said Rene Olivares-Navarrete from the VCU.
"Neural crest cells are extremely important in the development of craniofacial structures because they can form many different tissues like bones, cartilage, skin, teeth, and glands," Olivares-Navarrete said. E-cigarettes are connected to the pump, which "inhales" the vapor.
The researchers exposed the frog embryos to the saline-vapor mixture and recorded facial measurements and any incidents of cleft palates the embryos developed. They tested the effects of the mixture on the viability and function of neural crest cells. The results were surprising and strongly suggested using e-cigarettes could lead to birth defects, Dickinson said.
In experimental trials for specific e-liquid types, all the frog embryos developed cleft palates. "We observed that very complex e-liquids that mix flavors, such as berries and creme and other food-related flavorings, may have the most dramatic effect on the face," Dickinson said.