Chronic Pod-Mod E-Cigarette Aerosol Exposure Induces Aortic Dysfunction in Hypercholesterolemic Mice: Role of Oxidative Stress and Inflammation

Abstract

ObjectiveElectronic (e-)cigarettes are the most used tobacco product amongst youth, and adult smokers favor e-cigarettes over approved cessations aids. Despite the lower perceived harm of vaping compared to smoking, inhalation of e-cigarette aerosol elicits cardiovascular responses that may lead to permanent injury when repeated over time. We thus aimed to infer the long-term outcomes of vaping on the function and structure of the aorta and shed light on the underlying cellular and molecular mechanisms.Approach and ResultsWe exposed female hypercholesterolemic mice to either pod-mod e-cigarette aerosol or room air daily for 24 weeks. Chronic inhalation of e-cigarette aerosol triggered accumulation of inflam-matory signals systemically and within aortic tissues, as well as T lymphocyte accrual in the aortic wall. Reduced eNOS expression and enhanced ROS production following eNOS uncoupling and NADPH oxi-dase activation curbed nitric oxide availability in the aorta of mice exposed to e-cigarette aerosol, impairing the endothelium-dependent vasodilatation that regulates blood flow distribution. Inhalation of e-cigarette aerosol thickened and stiffened aortic tissues via collagen deposition and remodeling, hindering the storage of elastic energy and limiting the cyclic distensibility that enables the aorta to function as a pressure reservoir. These effects combined contributed to raising systolic and pulse pressure above control levels.ConclusionsChronic inhalation of aerosol from pod-mod e-cigarettes promotes oxidative stress, inflammation, and fibrosis within aortic tissues, significantly impairing passive and vasoactive aortic functions. This evidence provides new insights on the biological processes that increase the risk for adverse cardio-vascular events as a result of pod-mod e-cigarette vaping.