E-cigarettes: Effects in phagocytosis and cytokines response against Mycobacterium tuberculosis

Abstract

Cigarette smoking and tuberculosis are a significant cause of death worldwide. Several epidemiological studies have demonstrated cigarette smoking is a risk factor for tuberculosis. Electronic cigarettes have recently appeared as a healthier alternative to conventional smoking, although their impact in tuberculosis is not well understood. The aim of this study was to explore the effect of electronic cigarettes in phagocytosis of Mycobacterium tuberculosis and cytokines production. In vitro infection was carried out by exposing THP-1 macrophages to four electronic vapor extracts and the intracellular burden of M. tuberculosis was determined. The percentage of infection was evaluated by confocal microscopy and the cytokine production by Luminex. A reduction of intracellular M. tuberculosis burden in THP-1 macrophages was found after its exposure to electronic vapor extract; the same trend was observed by confocal microscopy when Mycobacterium bovis BCG-GFP strain was used. Electronic cigarettes stimulate a pro-inflammatory cytokine response. We conclude that electronic cigarettes impair the phagocytic function and the cytokine response to M. tuberculosis.

E-cigarette use and respiratory disorders: an integrative review of converging evidence from epidemiological and laboratory studies

“…Gilpin [87] and Gomez [88] exposed macrophages and several types of bacteria (e.g., influenza, pneumonia) to e-cigarette aerosol extract and found increased bacterial virulence and inflammatory potential as well as decreased bacteria-killing ability. A mouse study [89] found similar effects for macrophages and increased morbidity and mortality among influenza-infected animals, independent of nicotine.…”

“…Though these studies demonstrated effects of flavorings, some also found significant adverse effects for humectants alone. In several studies [87,88,89,91,92] some effects of e-cigarettes on immune function were less than for cigarettes but some were equal to cigarettes.…”

“…= related; STIM = stromal interaction molecule; permeab = membrane permeability; MMP = matrixmetalloprotease. Control conditions were clean air in [75,86,89,92,94], medium control in [84,85,87,90,91,93], untreated or littermate control in [84,88,95]. For other notes, see footnote for Supplementary Table 5.…”

“…In a series of cell studies and in vivo studies [ 86 ], lungs of mice exposed to e-cigarette aerosol and infected with Streptococcus pneumoniae showed increased bacterial burden, and mice infected with influenza virus showed a higher rate of mortality in the e-cigarette condition compared to a clean-air control. Similarly, G ilpin et al [ 87 ] and G ómez et al [ 88 ] exposed macrophages and several types of bacteria ( e.g. influenza, pneumonia) to e-cigarette aerosol extract and found increased bacterial virulence and inflammatory potential as well as decreased bacteria-killing ability.…”

Cardiorespiratory and Immunologic Effects of Electronic Cigarettes

“…Stimulation of cytokine production in macrophages by e-cigarette exposure is accompanied by a decrease in their phagocytic activity. Exposure of macrophages to e-cigarette aerosol condensate has been reported to result in a 50-fold increase in ROS production and a significant inhibition of phagocytosis [ 83 ], efferocytosis, and bacterial clearance [ 89 ], and exposing THP-1 macrophages to e-cigarette aerosol extracts has been shown to decrease the intracellular burden of Mycobacterium tuberculosis [ 90 ]. Similarly, when exposed to freshly generated e-cigarette aerosol at the air-liquid interface, alveolar macrophages and neutrophils show reduced anti-microbial activity against Staphylococcus aureus [ 91 ].…”