The health effects of ‘vaping’, or inhaling the aerosol generated by e-cigarettes, are largely unknown, writes Jenna Flogeras for Advanced Science News. Researchers from the University of Cambridge and MINES St Etienne measured tracheal barrier integrity after aerosol exposure from e-cigarettes – and found them harmful.
Originally intended for use as a stop-smoking aid, the recreational use of e-cigarettes is growing. The vaping phenomenon has elicited some controversy by spawning nicotine addiction among non-smokers, including youth and minors, who are more likely to find the assortment of candy-flavored pods available on the market appealing – not to mention the sleek e-cigarette designs, which make for fashionable accessories.
How e-cigarettes affect the tracheal epithelium, which acts as a barrier to prevent the entrance of harmful inhaled particles into the body, is not well known and has prompted the development of in vitro methods to analyze aerosol toxicity. Current commercial technologies are unable to provide an assessment of tracheal barrier integrity under physiological conditions.
University of Cambridge researcher Dr Róisín M Owens, Dr Marc Ramuz of MINES St Étienne, and co-workers have developed a sensing platform to measure tracheal barrier integrity at the air-liquid interface (ALI) after aerosol exposure from e-cigarettes.Their research was reported in the journal Advanced Biosystems last month.
Their device, which consists of an organic electrochemical resistor (OECT) combined with a conformal flexible gate (fg), enables continuous electrical measurement at the ALI and does not rely on liquids – a limitation of previous studies.
A human airway epithelium model was exposed to e-cigarette aerosols from an e-liquid mixture of propylene glycol, vegetable glycerin, and nicotine in concentrations corresponding to 25 and 30 puffs. Electrical measurements using the fg-OECT over four hours showed that the complete loss of epithelial barrier properties occurs within 3.5 hours of aerosol exposure.
Results suggest that the aerosol produced from e-cigarettes should be considered harmful, but a model that measures exposure over a longer period (that is, several days or weeks) is needed to more thoroughly investigate the cytotoxic effects of e-cigarettes.
This technology could potentially be adapted to in vitro studies for other tissues with ALIs, including lungs and skin.
Effect of E Cigarette Emissions on Tracheal Cells Monitored at the Air-Liquid Interface Using an Organic Electrochemical Transistor
E‐cigarettes have been suggested as a potentially healthier alternative to cigarettes based on studies using cell viability, DNA damage, and transcriptional response assays.
However, little is known about the effect of e‐cigarette aerosols on the integrity of the tracheal epithelium, specifically with respect to barrier resistance. This is partly due to the lack of methods for monitoring epithelia at the air-liquid interface (ALI), i.e., under physiological conditions.
Here, it is shown that an organic electrochemical transistor can be adapted for the measurement of barrier resistance at the ALI.
This technology enables accurate, continuous quantification of tracheal barrier integrity through the use of a conformable gate electrode placed on top of the cell‐secreted mucus, obviating the need for addition of culture medium or buffer as a conductance medium for rigid electrodes. The platform allows for the detection of a dose‐dependent, rapid decrease in barrier resistance of an in vitro model of human bronchial epithelium (MucilAir) after E‐cigarette aerosols exposure.
The system represents a powerful tool to study tissue responses of the human airway epithelium to inhaled smoke. The same technology will have broad applications for toxicology studies on other tissues with ALI, including other airway tissues and skin.
E-Cigarettes: Friend or Foe? Effect of E Cigarette Emissions on Tracheal Cells Monitored at the Air–Liquid Interface Using an Organic Electrochemical Transistor
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