Tobacco and marijuana induce adverse effects on cardiac function and platelet activity and reduce tissue preservation following myocardial infarction.

Abstract

Smoking disrupts cardiac autonomic regulation, vascular biology, and platelet function; however, the acute and longer-term cardiovascular effects of resurging and emerging tobacco and marijuana products remain incompletely characterized. We investigated the impact of exposure to smoke and aerosol from several tobacco and marijuana products on cardiac function, platelet activity, and myocardial susceptibility to ischemia-reperfusion myocardial infarction (MI). Male and female Sprague-Dawley rats underwent single or daily 5-min pulsatile exposure sessions to emissions from tobacco cigarettes, e-cigarettes (JUUL), heated tobacco products (IQOS), marijuana cigarettes, or cannabinoid-depleted ("placebo") marijuana cigarettes, with an air negative control. Cardiac function was assessed immediately after single exposure by echocardiography and intraventricular hemodynamics. Platelet aggregation was measured immediately after single exposure and 1 day after repeated (2-wk) exposure. Myocardial infarct size, normalized to area at risk, was assessed following MI after repeated (4-wk) exposure. Single exposure to tobacco smoke or JUUL aerosol reduced left ventricular ejection fraction relative to preexposure. Acute marijuana smoke exposure similarly impaired left ventricular function assessed by hemodynamics. Single exposure to tobacco, marijuana, and placebo marijuana smoke increased collagen-induced platelet aggregation, with more pronounced responses in females, whereas repeated (2-wk) exposure to smoke/aerosol from tobacco cigarettes, JUUL, IQOS, and placebo marijuana increased platelet aggregation across groups. Notably, repeated (4-wk) exposure to tobacco smoke/aerosol or marijuana smoke before MI reduced myocardial tissue preservation, resulting in greater infarct size post MI. These findings indicate that individual tobacco and marijuana smoking and vaping similarly impair cardiac function, enhance platelet reactivity, and reduce myocardial tolerance to ischemia-reperfusion injury.NEW & NOTEWORTHY Inhalable products marketed as reduced-harm alternatives to combustible cigarettes, including e-cigarettes, heated tobacco products, and marijuana, produce rapid and sustained adverse cardiovascular effects. Even brief exposure impairs cardiac function and enhances platelet aggregation, whereas prior exposure increases myocardial susceptibility to ischemia-reperfusion injury, resulting in larger infarcts following myocardial infarction. These findings challenge the perception that noncombustible or "reduced-harm" products are cardiovascularly benign.