Researchers from University of Birmingham and Swansea University in the UK devised a mechanical procedure to mimic vaping and produce condensate from the vapour.
They extracted alveolar macrophages from lung tissue samples provided by eight non-smokers who had never had asthma or chronic obstructive pulmonary disease (COPD).
A third of the cells were exposed to plain e-cigarette fluid, a third to different strengths of the artificially vaped condensate with and without nicotine, and a third to nothing for 24 hours.
The results showed that the condensate was significantly more harmful to the cells than e-cigarette fluid and that these effects worsened as the 'dose' increased.
After 24 hours of exposure the total number of viable cells exposed to the vaped condensate was significantly reduced compared to the untreated cells, and condensate containing nicotine exaggerated this effect.
Exposure to the condensate increased cell death and boosted production of oxygen free radicals by a factor of 50, and it significantly increased the production of inflammatory chemicals - more so when the condensate contained nicotine.
What is more, the ability of cells exposed to vaped condensate to engulf bacteria was significantly impaired, although treatment with an antioxidant restored this function and helped lessen some of the other harmful effects.
The researchers conclude that the vaping process itself can damage vital immune system cells, at least under laboratory conditions.
"Importantly, exposure of macrophages to [e-cigarette vapour condensate] induced many of the same cellular and functional changes in [alveolar macrophage] function seen in cigarette smokers and patients with COPD," they said.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)