E-Cigarette Use: Device Market, Study Design, and Emerging Evidence of Biological Consequences

Int J Mol Sci. 2021 Nov 18;22(22):12452. doi: 10.3390/ijms222212452.


Electronic cigarettes are frequently viewed as a safer alternative to conventional cigarettes; however, evidence to support this perspective has not materialized. Indeed, the current literature reports that electronic cigarette use is associated with both acute lung injury and subclinical dysfunction to the lung and vasculature that may result in pathology following chronic use. E-cigarettes can alter vascular dynamics, polarize innate immune populations towards a proinflammatory state, compromise barrier function in the pulmonary endothelium and epithelium, and promote pre-oncogenic phenomena. This review will summarize the variety of e-cigarette products available to users, discuss current challenges in e-cigarette study design, outline the range of pathologies occurring in cases of e-cigarette associated acute lung injury, highlight disease supporting tissue- and cellular-level changes resulting from e-cigarette exposure, and briefly examine how these changes may promote tumorigenesis. Continued research of the mechanisms by which e-cigarettes induce pathology benefit users and clinicians by resulting in increased regulation of vaping devices, informing treatments for emerging diseases e-cigarettes produce, and increasing public awareness to reduce e-cigarette use and the onset of preventable disease.

Keywords: EVALI; ROS; e-cigarette; e-liquid; endothelium; epithelium; macrophage; neutrophil; platelets; vaping.

Publication types

  • Review

MeSH terms

  • Acute Lung Injury / chemically induced
  • Acute Lung Injury / immunology
  • Acute Lung Injury / pathology*
  • Animals
  • Blood Platelets / drug effects
  • Blood Platelets / immunology
  • Blood Platelets / pathology
  • Carcinogenesis / immunology
  • Carcinogenesis / pathology
  • Cardiovascular Diseases / chemically induced
  • Cardiovascular Diseases / immunology
  • Cardiovascular Diseases / pathology*
  • Cytokines / biosynthesis
  • Cytokines / immunology
  • Electronic Nicotine Delivery Systems*
  • Humans
  • Immunity, Innate / drug effects
  • Lung / drug effects
  • Lung / immunology
  • Lung / pathology
  • Lung Neoplasms / chemically induced
  • Lung Neoplasms / immunology
  • Lung Neoplasms / pathology*
  • Macrophages / drug effects
  • Macrophages / immunology
  • Macrophages / pathology
  • Neovascularization, Pathologic / chemically induced
  • Neovascularization, Pathologic / immunology
  • Neovascularization, Pathologic / pathology
  • Neutrophils / drug effects
  • Neutrophils / immunology
  • Neutrophils / pathology
  • Reactive Oxygen Species / immunology
  • Reactive Oxygen Species / metabolism
  • Respiratory Mucosa / drug effects
  • Respiratory Mucosa / immunology
  • Respiratory Mucosa / pathology
  • Rodentia
  • Vaping / immunology
  • Vaping / pathology*


  • Cytokines
  • Reactive Oxygen Species