Summary
Introduction:
This article reports a study comparing the effects of electronic cigarette (EC) aerosol extracts and cigarette smoke extract (CSE) on human neutrophils and platelets in vitro. The study aimed to investigate and compare the immunomodulatory effects of EC and CSE on key components of the innate immune system.
Key points:
* The study used aqueous extracts derived from the aerosols of nicotine-free ECs (ECE −Nico), nicotine-containing ECs (ECE+Nico), and CSE.
* Neutrophils were isolated from heparinised venous blood from healthy adult volunteers and pre-incubated with the extracts.
* The generation of ROS, elastase release, and extracellular DNa (NET) formation were measured using chemiluminescence, spectrophotometric, and microscopic procedures, respectively.
* Platelet reactivity was measured according to the magnitude of upregulated expression of the adhesion molecule CD62P on activated cells using a flow cytometric procedure.
* Exposure of neutrophils to either ECEs or CSE caused a significant inhibition of ROS generation and elastase release.
* Pre-treatment of neutrophils with CSE, but not the ECEs, resulted in a marked attenuation of phorbol 12-myristate 13-acetate-mediated release of extracellular DNa.
* CSE, but not the ECEs, inhibited the expression of CD62P by platelets activated with aDP.
Main message:
The study suggests that EC aerosol extracts may inhibit some of the immuno-protective activities of neutrophils, such as ROS production and elastase release, but to a lesser extent than CSE. The inhibitory effects of CSE were significantly more pronounced, especially for suppression of NET formation and platelet activation. These harmful immunosuppressive effects of EC aerosols may compromise intrinsic pulmonary antimicrobial defense mechanisms, albeit less so than cigarette smoke. Therefore, it is crucial to consider the potential risks associated with EC use, especially in susceptible populations such as those with compromised immune systems.
Citation
Richards Ga, Theron aJ, van den Bout I, et al. Comparison of the effects of electronic cigarette vapours and tobacco smoke extracts on human neutrophils in vitro. ERJ open research. 2023;9(3). doi:10.1183/23120541.00502-2022
