Exposure to Electronic Cigarettes Impairs Pulmonary Anti-Bacterial and Anti-Viral Defenses in a Mouse Model

• Published in: PloS one Vol. 10; no. 2; p. e0116861
• Main Authors: Sussan, Thomas E., Gajghate, Sachin, Thimmulappa, Rajesh K., Ma, Jinfang, Kim, Jung-Hyun, Sudini, Kuladeep, Consolini, Nicola, Cormier, Stephania A., Lomnicki, Slawo, Hasan, Farhana, Pekosz, Andrew, Biswal, Shyam
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.02.2015; Public Library of Science (PLoS)
• Subjects: Alveoli; Analysis; Animal models; Animals; Antibacterial agents; Antiinfectives and antibacterials; Antimicrobial agents; Antiviral agents; Bacteria; Bacterial infections; Chronic obstructive pulmonary disease; Cigarette smoking; Cotinine; Cytokines; Cytotoxicity; Electronic cigarettes; Environmental health; Exposure; Free radicals; Free Radicals - analysis; Gene expression; Health aspects; Health sciences; Immune clearance; Immune response; Immune system; In vivo methods and tests; Infections; Inflammation; Influenza; Influenza A; Influenza A Virus, H1N1 Subtype - physiology; Inhalation; Lung - drug effects; Lung - immunology; Lung - microbiology; Lung - virology; Lungs; Macrophages; Male; Marketing; Mice; Mice, Inbred C57BL; Microorganisms; Nicotine; Nicotine - adverse effects; Nicotine - chemistry; Oxidative stress; Oxidative Stress - drug effects; Perception; Phagocytosis; Phagocytosis - drug effects; Pneumonia; Public health; Respiration; Smoking; Smoking - adverse effects; Smoking cessation; Streptococcus infections; Streptococcus pneumoniae - physiology; Tobacco; Vapors; Viral infections; Viral Load - drug effects; Viruses; VOCs; Volatile organic compounds; Volatilization; Louisiana; Baton Rouge Louisiana; United States > US; Maryland; Baltimore Maryland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0116861

Electronic cigarettes (E-cigs) have experienced sharp increases in popularity over the past five years due to many factors, including aggressive marketing, increased restrictions on conventional cigarettes, and a perception that E-cigs are healthy alternatives to cigarettes. Despite this perception, studies on health effects in humans are extremely limited and in vivo animal models have not been generated. Presently, we determined that E-cig vapor contains 7 x 10(11) free radicals per puff. To determine whether E-cig exposure impacts pulmonary responses in mice, we developed an inhalation chamber for E-cig exposure. Mice that were exposed to E-cig vapor contained serum cotinine concentrations that are comparable to human E-cig users. E-cig exposure for 2 weeks produced a significant increase in oxidative stress and moderate macrophage-mediated inflammation. Since, COPD patients are susceptible to bacterial and viral infections, we tested effects of E-cigs on immune response. Mice that were exposed to E-cig vapor showed significantly impaired pulmonary bacterial clearance, compared to air-exposed mice, following an intranasal infection with Streptococcus pneumonia. This defective bacterial clearance was partially due to reduced phagocytosis by alveolar macrophages from E-cig exposed mice. In response to Influenza A virus infection, E-cig exposed mice displayed increased lung viral titers and enhanced virus-induced illness and mortality. In summary, this study reports a murine model of E-cig exposure and demonstrates that E-cig exposure elicits impaired pulmonary anti-microbial defenses. Hence, E-cig exposure as an alternative to cigarette smoking must be rigorously tested in users for their effects on immune response and susceptibility to bacterial and viral infections.