Vaping Additives Affect Lateral Organization and Functionality of Lung Surfactant Model Systems
Date
2022-07-28
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Abstract
Recent use of THC-based vapes has led to an outbreak of respiratory health issues. While the pathology is unresolved, common symptoms point to dysfunction of the lung surfactant (LS). This is a lipid-protein monofilm situated at the air-water interface in alveolar sacs, which acts to lower surface tension, preventing lung collapse during respiration. Inhaled substances that reach the alveoli will encounter LS. Certain vape additives have been identified as potential causative agents, these being tetrahydrocannabinol and cannabidiol, commonly found in THC products, as well as vitamin E and its derivative vitamin E acetate. The lipophilic nature of these additives may allow them to partition into the monofilm, wherein they could interact with lipids to disrupt proper function. The aim of this thesis was to use model surfactants to better understand the interactions between vaping additives and the primary lipid components of lung surfactant. These films were made up of phosphatidylcholines, phosphatidylglycerols, and cholesterol. Additionally, the clinical surfactant BLES was also used and compared to the model systems. BLES is used in surfactant replacement therapy, making it a good physiological counterpart to the simple model films studied. Surface activity of the films were measured using a Langmuir-Blodgett trough which allowed for compression and expansion of the films, mimicking respiration. Changes to the lateral organization of the films was conducted with Brewster angle microscopy. Visualization of BLES was also carried out with atomic force microscopy, which allowed for higher resolution images of the surfactant’s molecular architecture. Vape additives were found to destabilize domain formations in most systems, often accompanied by fluidization of the film. The effects on BLES provided a unique insight into the mechanistic action of additive induced surfactant dysfunction. Crucial multilayer structures that form on the surface of the film during compression were abolished in the presence of vitamin E acetate, reducing the surfactants ability to maintain a low surface tension. The Langmuir-Blodgett trough has demonstrated to be useful for studying in vitro interactions between lipids and vape additives. With further optimization, this method may be used to predict in vivo effects of vape additives.
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Keywords
Vaping additives, Lung surfactant
Citation
Van Bavel, N. (2022). Vaping Additives Affect Lateral Organization and Functionality of Lung Surfactant Model Systems (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.