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

BACKGROUND: Electronic cigarettes (e-cigarettes) are the most used tobacco product among youth, and adults who smoke combustible cigarettes favor e-cigarettes over approved cessation aids. Despite the lower perceived harm of vaping compared with smoking, acute inhalation of e-cigarette aerosol elicits cardiovascular responses that may lead to persistent damage when repeated over time. METHODS: We exposed female hypercholesterolemic mice to either pod-mod e-cigarette aerosol or filtered air daily for 24 weeks. We assessed the long-term effects of vaping on aortic stiffness and vasoreactivity while investigating the underlying cellular and molecular mechanisms of injury. RESULTS: Chronic inhalation of e-cigarette aerosol triggered the accumulation of inflammatory signals systemically and within aortic tissues, as well as T-lymphocyte accrual in the aortic wall. Limited eNOS (endothelial nitric oxide synthase) expression and enhanced superoxide radical production curbed NO bioavailability in the aorta of mice exposed to e-cigarette aerosol despite iNOS (inducible nitric oxide synthase) induction, impairing the endothelium-dependent vasodilation 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. CONCLUSIONS: Chronic 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 into the biological processes that increase the risk of adverse cardiovascular events as a result of pod-mod e-cigarette vaping.