Pod-Based e-Cigarettes Cause Mitochondrial Dysfunction, Eventual Lung Injury

Electronic cigarette (e-cigarette) use is increasing in Western populations, notably among middle school and high school students. As respiratory illnesses linked to vaping have emerged, some states have banned sales of flavored e-cigarettes, in some cases making an exception for tobacco flavors. However, the health effects of e-cigarettes remain unclear. Researchers recently explored the impacts of pod-based e-cigarette flavors, hypothesizing that they would decrease mitochondrial function and induce mitochondrial superoxide production. The results were published online as part of the ATS 2020 International Conference.
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The researchers measured mitochondrial oxidation-phosphorylation in lung epithelial cells (Beas2b) on seahorse plates, which were exposed to either air or pod-based e-cigarette aerosols three times for 30 minutes each. Mitochondrial respiration with the Cell Mito Stress Test kit using the Seahorse XFp analyzer was measured immediately following and one day after exposure. Mitochondrial superoxide production was also measured, with the cells again exposed to either air or pod-based e-cigarette aerosols in three 30-minute sessions. Cells were measured six hours following the final exposure by flow cytometry with the Guava Millipore Easycyte-8 instrument.

Right after the last exposure to JUUL menthol aerosol, compared with air controls, the cells presented a significant increase in non-mitochondrial oxygen consumption, with an oxygen consumption rate (OCR) of 0.38 pmol/min/cells*1000, as well as proton leak, with an OCR of 0.29 pmol/min/cells*1000. The JUUL menthol aerosol-exposed cells also had decreased coupling efficiency compared with air controls.

One day after the final JUUL menthol aerosol exposure, compared with air controls, a significant increase in non-mitochondrial oxygen consumption was observed, with an OCR of 0.43 pmol/min/cells*1000, as well as a significant decrease in basal respiration, with an OCR of 1.0 pmol/min/cells*1000; maximal respiration, with an OCR of 2.3 pmol/min/cells*1000; and spare capacity, with an OCR of 1.3 pmol/min/cells*1000. The JUUL menthol aerosol-exposed cells also presented an increase in MitoSox high and Annexin V low cell populations and a decrease in MitoSox low and Annexin V low cell populations when compared with air controls.

The researchers concluded, “These results may indicate that prolonged exposure to pod-based electronic cigarette may result in lung injury due to this mitochondrial dysfunction.”