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 Traditional cigarettes have long been linked to an increased risk of
pneumonia, but it’s been less clear whether e-cigarettes might have
the same effect.
To find out, researchers did a series of laboratory experiments to
see whether exposure to e-cigarette vapor might increase levels of a
molecule produced by airway lining cells, called platelet-activating
factor receptor (PAFR).
Pneumococcal bacteria use PAFR to help them adhere to airway cells.
First, the researchers exposed some human airway epithelial cells in
culture dishes to e-cigarette vapor. Compared to cells that weren’t
exposed, those that were had PAFR levels three times higher.
Then, they exposed mice to e-cigarette vapor and found higher PAFR
production in the rodents who inhaled the fumes.
Finally, the researchers asked 17 people who were regular vapers to
come smoke an e-cigarette in the lab. Compared with these
participants’ PAFR levels measured before the vaping session, there
was a three-fold increase in PAFR levels an hour after people smoked
e-cigarettes.
“The take-home message is that it is over-optimistic to assume that
all of the adverse effects of cigarette smoking are reduced by
switching to vaping,” said senior study author Jonathan Grigg of
Queen Mary University of London.
“It also raises the question that, even if we have not proved that
vaping increases the risk of pneumonia, for young people taking up
vaping for the first time, a precautionary approach would suggest
that the risk should be assumed to exist until proved otherwise,”
Grigg said by email.
Big U.S. tobacco companies are all developing e-cigarettes. The
battery-powered gadgets feature a glowing tip and a heating element
that turns liquid nicotine and flavorings into a cloud of vapor that
users inhale.
Even when e-liquids don’t contain nicotine, the lungs are still
exposed to flavoring chemicals when the e-liquids are heated and the
vapors are inhaled.
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Some previous research, mostly in lab experiments, has linked
exposure to these flavorings to an increase in biomarkers for
inflammation and tissue damage. This type of cell damage can lead to
lung problems including fibrosis, chronic obstructive pulmonary
disorder and asthma.
In the current lab experiment, PAFR levels surged in human nose
lining cells in culture dishes exposed to e-liquids with nicotine
and in cells exposed to nicotine-free vapor. This was accompanied by
increased adhesion by pneumonia-causing bacteria.
Even though the study is small and the results must be verified in
larger human trials, the findings still suggest that e-cigarettes
aren’t risk-free and shouldn’t necessarily be considered a safe way
for people to try to curb use of traditional cigarettes, the
researchers conclude in the European Respiratory Journal.
At least when it comes to pneumonia, nicotine patches or gum may be
a safer option for smoking cessation, the researchers note.
“PAFR expression is enhanced in cigarette smokers and patients with
chronic obstructive pulmonary disorder and has been hypothesized to
be mediating enhanced adhesion of bacteria to epithelial cells and
subsequent development of pneumonia,” said Ilona Jaspers, deputy
director of the Center for Environmental Medicine, Asthma & Lung
Biology at the University of North Carolina at Chapel Hill.
“The data shown here suggest that vaping e-cigarettes could also
increase expression of PAFR in relevant epithelial cells,” Jaspers,
who wasn’t involved in the study, said by email. “In general, I
would refrain from calling e-cigarettes ‘safer’ than cigarettes, but
would suggest calling them causing ‘different’ effects than
cigarettes.”
SOURCE: http://bit.ly/2nV3Ts7 European Respiratory Journal, online
February 7, 2018.
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