Electronic cigarettes (ECIGs) are electronic devices that heat and vaporize a solution that usually contains a mixture of glycerol, propylene glycol, water, flavors and various concentrations of nicotine. ECIGs have 3 key components: A power source, a cartridge containing an atomizer along with a liquid solution and a mouthpiece. The solution (often known as e-liquid or e-juice) is heated into an aerosol inhaled by the user. Smoking conventional cigarettes is considered a determinant factor in the development of chronic respiratory diseases, cardiovascular diseases, cancers, and reproductive system dysfunctions. Conventional smoking also causes genome damage and alteration of the transcriptome, due to the amounts of noxious substances emitted during the combustion of these products. Recently, cigarette consumers have begun to use ECIGs as a replacement or substitute practice to help them quit smoking. In addition, an increase in the use of ECIGs and similar devices by young individuals has been reported, which is unsurprising due to the unregulated distribution and sale of these products. The present review article describes and discusses the impact and the noxious effects of substances in ECIGs and other nicotine administration systems on DNA structure, gene expression profile, and epigenetic modification, focusing on the respiratory system and embryonic development.

El proceso transición epitelio mesénquima (TEM) permite que una célula epitelial de manera temporal, adquiera un fenotipo mesenquimal como respuesta a un estímulo interno o externo. Este proceso se caracteriza  por la activación y represión de genes involucrados en diferentes vías de señalización asociadas con migración, invasión y apoptosis, entre otros. En este proceso la epigenética cumple un papel fundamental. La epigenética comprende cuatro mecanismos: metilación de ADN, modificación covalente de histonas, ARN no codificantes (ARNnc) y complejos remodeladores de la cromatina, que regulan la expresión de un gen sin alterar su secuencia. En esta revisión de tema los autores describen los principales mecanismos epigenéticos involucrados en la regulación de la expresión de genes que se activan y reprimen concomitantemente en las tres fases del proceso TEM: fase no migratoria, fase premigratoria y fase migratoria.