Menthol in electronic cigarettes causes biophysical inhibition of pulmonary surfactant.

Introduction:
This article discusses the impact of electronic cigarette (e-cigarette) aerosols on pulmonary surfactant, a crucial substance that lines the alveoli and reduces surface tension to enable effective gas exchange. The authors used constrained drop surfactometry, atomic force microscopy, 13C-NMR, circular dichroism, and molecular dynamics simulations to investigate the effects of individual e-cigarette liquid components on surfactant function.

Key Points:

* E-cigarette aerosols (ECas) consist mostly of submicron particles that deposit in the alveolar region of the lung and interact with pulmonary surfactant.
* Exposure to e-cigarette aerosols increases the minimum surface tension and film compressibility of pulmonary surfactant.
* Menthol, a popular e-cigarette flavoring, is the primary chemical compound in ECas that inhibits surfactant biophysical function.
* Menthol interacts with both surfactant phospholipids and proteins, disrupting phospholipid packing and impairing the formation of surfactant multilayers.
* Ethyl maltol and ethyl butyrate, other common flavorings, also negatively affect surfactant biophysical function but to a lesser extent than menthol.
* Nicotine alone has a minimal impact on surfactant biophysical function.
* The health impact of menthol-flavored e-cigarettes needs further investigation, as the FDa has proposed banning menthol in combustible cigarettes, potentially leading to increased use of menthol-flavored e-cigarettes.

Main Message:
This study highlights the significant role of menthol in e-cigarette aerosols' adverse effects on pulmonary surfactant, which can contribute to respiratory dysfunction. With the FDa's proposed ban on menthol in combustible cigarettes and the potential for increased e-cigarette usage, understanding the health implications of menthol-flavored e-cigarettes is crucial for better regulation and risk mitigation.

Xu L, Yang Y, Simien JM, et al. Menthol in electronic cigarettes causes biophysical inhibition of pulmonary surfactant. american journal of physiology Lung cellular and molecular physiology. 2022;323(2):L165-L177. doi:10.1152/ajplung.00015.2022