Biomedical Engineering Program, Department of Chemical and Biomolecular Engineering, 168 Stocker Center, Ohio University, Athens, OH, 45701, USA.
School of Electrical Engineering and Computer Science, Ohio University, Athens, OH, 45701, USA.
Respir Res. 2017 Nov 17;18(1):193. doi: 10.1186/s12931-017-0676-9.
Despite their growing popularity, the potential respiratory toxicity of electronic cigarettes (e-cigarettes) remains largely unknown. One potential aspect of e-cigarette toxicity is the effect of e-cigarette vapor on lung surfactant function. Lung surfactant is a mixture of lipids and proteins that lines the alveolar region. The surfactant layer reduces the surface tension of the alveolar fluid, thereby playing a crucial role in lung stability. Due to their small size, particulates in e-cigarette vapor can penetrate the deep lungs and come into contact with the lung surfactant. The current study sought to examine the potential adverse effects of e-cigarette vapor and conventional cigarette smoke on lung surfactant interfacial properties.
Infasurf, a clinically used and commercially available calf lung surfactant extract, was used as lung surfactant model. Infasurf films were spread on top of an aqueous subphase in a Langmuir trough with smoke particulates from conventional cigarettes or vapor from different flavors of e-cigarettes dispersed in the subphase. Surfactant interfacial properties were measured in real-time upon surface compression while surfactant lateral structure after exposure to smoke or vapor was examined using atomic force microscopy (AFM).
E-cigarette vapor regardless of the dose and flavoring of the e-liquid did not affect surfactant interfacial properties. In contrast, smoke from conventional cigarettes had a drastic, dose-dependent effect on Infasurf interfacial properties reducing the maximum surface pressure from 65.1 ± 0.2 mN/m to 46.1 ± 1.3 mN/m at the highest dose. Cigarette smoke and e-cigarette vapor both altered surfactant microstructure resulting in an increase in the area of lipid multilayers. Studies with individual smoke components revealed that tar was the smoke component most disruptive to surfactant function.
While both e-cigarette vapor and conventional cigarette smoke affect surfactant lateral structure, only cigarette smoke disrupts surfactant interfacial properties. The surfactant inhibitory compound in conventional cigarettes is tar, which is a product of burning and is thus absent in e-cigarette vapor.
尽管电子烟越来越受欢迎，但它们潜在的呼吸道毒性在很大程度上仍不为人知。电子烟毒性的一个潜在方面是电子烟蒸汽对肺表面活性剂功能的影响。肺表面活性剂是一种排列在肺泡区域的脂质和蛋白质混合物。表面活性剂层降低肺泡液的表面张力，因此在肺稳定性中起着至关重要的作用。由于电子烟蒸汽中的颗粒较小，它们可以穿透深部肺部并与肺表面活性剂接触。本研究旨在检查电子烟蒸汽和传统香烟烟雾对肺表面活性剂界面特性的潜在不良影响。
使用临床上使用的和市售的小牛肺表面活性剂提取物 Infasurf 作为肺表面活性剂模型。Infasurf 薄膜铺展在 Langmuir 槽的水亚相中，亚相中分散有来自传统香烟的烟雾颗粒或不同口味电子烟的蒸汽。在表面压缩的同时实时测量表面活性剂界面特性，并且在用烟雾或蒸汽暴露后使用原子力显微镜（AFM）检查表面活性剂的横向结构。
电子烟蒸汽无论电子烟液的剂量和口味如何，都不会影响表面活性剂的界面特性。相比之下，来自传统香烟的烟雾对 Infasurf 界面特性有剧烈的、剂量依赖性的影响，在最高剂量下将最大表面压力从 65.1±0.2 mN/m 降低到 46.1±1.3 mN/m。香烟烟雾和电子烟蒸汽都改变了表面活性剂的微观结构，导致脂质多层的面积增加。对单个烟雾成分的研究表明，焦油是对表面活性剂功能最具破坏性的烟雾成分。
虽然电子烟蒸汽和传统香烟烟雾都影响表面活性剂的横向结构，但只有香烟烟雾会破坏表面活性剂的界面特性。传统香烟中的表面活性剂抑制化合物是焦油，它是燃烧的产物，因此在电子烟蒸汽中不存在。
