Research finds e-cig vapour disables key immune cells in the lung

Research led by the University of Birmingham has found that vapourised e-liquid fluid has a similar effect on the lungs and body that is seen in regular cigarette smokers and patients with chronic lung disease.

The research, published in Thorax and funded by the British Lung Foundation, shows that e-liquid that has been vapourised through the use of an electronic ‘e-cigarette’ boosts the production of inflammatory chemicals and disables key protective cells in the lungs that keep the air spaces clear of potentially harmful particles.

They found that vapour impairs the activity of cells, called alveolar macrophages, which are key to the immune response within the airways. Alveolar macrophages engulf and remove dust, bacteria, and allergens that have evaded the other mechanical defences of the respiratory tract.

The findings have prompted the researchers to suggest that, while further studies are needed to better understand the health effects of vaping on people, e-cigarettes may be more harmful than we think.

Professor David Thickett, of the University of Birmingham’s Institute of Inflammation and Ageing, said: “Cigarette smoking is associated with the cause of almost every lung disease – lung cancer, asthma, COPD and fibrosis.

“It has been suggested electronic cigarettes are safer than traditional cigarettes, and this narrative is increasingly supported by tobacco companies that have established research institutes devoted to generating supportive data.

“E-cigarette users have been given advice based on relatively little information. We hope that by disseminating this data as widely as possible the public can at least make an informed choice; the public must be aware that these devices are not harmless.

“We hope this information will be taken on board by advisory bodies when considering their public advice strategy. We also hope this highlights the need for dedicated funding and research to determine the long term effects of e-cigarette usage.”

Dr Aaron Scott, also of the University of Birmingham’s Institute of Inflammation and Ageing, said: “Several previous studies have examined the effects of unvaped e-cigarette liquid however, it is well established that the vapourising process changes the chemical composition of the liquid.

“The use of vaped liquid in our study makes this a better reflection of the exposure of the user, allowing us to examine whether e-cigarettes have a negative impact on the viability and function of cells called alveolar macrophages, which are key to the immune response within the airways.

“Our work clearly shows that vapourised e-cigarette fluid is toxic to living cells; increases the production of inflammatory chemicals; and inhibits the function of cells that are key to the immune stystem.

“Importantly, we found that exposure of these cells to e-cigarette vapour induced many of the same cellular and functional changes in function seen in cigarette smokers and patients with COPD.

“While further research is needed to fully understand the effects of e-cigarette exposure in humans in vivo, we suggest continued caution against the widely held opinion that e-cigarettes are safe.”

To find out the impact of vaping e-liquid, the researchers 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 50-fold and significantly increased the production of inflammatory chemicals – more so with condensate containing nicotine.

What’s 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.