Human bronchial epithelial cells cultured to diluted cinnamon e-liquids and e-liquid aerosols from an e-cigarette device were used to conduct analysis. Frequency of movement from hair like cilia projections which clear dirt and mucus from the lungs beat frequency was measured over two hours using high speed digital camera and video analysis systems. Each e-liquid cinnamaldehyde content was determined and human bronchial epithelial cells were exposed to the various concentrations to determine if cilia beat frequency changes with dosage, and mitochondrial oxidation phosphorylation changes were evaluated.
There are several different reactive aldehydes chemicals are found in cigarette smoke which cause lung inflammation and increase susceptibility to viral and bacterial infections. E-cigarettes have gained popularity being said to be a possibly safer alternative to cigarettes as they provide the sensation of smoking and nicotine effects without burning tobacco, however this and other studies add to discussions and growing bodies of evidence that call those claims into question.
Chemicals are contained within e-cigarette emissions which have not been evaluated for inhalation toxicities. Inhalation of flavoring agents poses numerous unknowns in regards to health risks as many of the chemicals are structurally similar to toxic aldehydes contained in cigarette smoke. These aldehyde flavoring agents are often used in extremely high concentration which could lead to high dose exposures, the two principles of toxicology clearly can apply here.
Data provided by this study significantly adds to the knowledge of how common food safe flavoring agents in the context of e-cigarette use can be altered, and can affect immune defense responses within the lungs. It was observed that a single acute exposure of cinnamaldehyde containing e-liquid temporarily impaired mitochondrial functions, reduced intracellular energy production, and stopped motile cilia within human airway epithelial cells. Studies show that substances which impair airway cilia structure and function enhance susceptibility to respiratory infections, and can have implications for various lung diseases, noted the researchers. Additional studies are required to determine whether e-cigarette aerosols impair mucociliary clearance in user in vivo.
This study was conducted because many food additives that are generally recognized as safe by the FDA have been added to e-cigarettes without further studies of their effects or if they become altered in this use when inhaled, and concern after investigating chemical structures of various e-cigarette flavoring agents that have chemical structures similar to those found in cigarette smoke with know toxicities, according to the researchers.
