Health Effects of E Cigarettes Kansas Health Institute Chronic electronic cigarette exposure in mice induces features of COPD in a nicotine dependent manner Thorax E liquids and vanillin flavoring disrupts retinoic acid signaling and causes craniofacial defects in Xenopus embryos ScienceDirect E cigarette aerosol exposure can cause craniofacial defects in Xenopus laevis embryos and mammalian neural crest cells PLOS One Differential Toxicity of Electronic Cigarette Aerosols Generated from Different Generations of Devices In Vitro and In Vivo Environment & Health