A recent study has demonstrated that the use of e-cigarettes is linked to adverse biological changes that can cause disease.
E-cigarettes are battery-powered devices that heat a liquid into an aerosol that the user then inhales and exhales. The liquid consists of solvents, flavouring and varying concentrations of nicotine. Chemical analysis of e-cigarette vapour has revealed the presence of some of the same toxicants and carcinogens that are found in cigarette smoke. As they are generally found at much lower levels, there is a common perception that e-cigarettes are safe or less harmful than cigarette smoking. However, the use of e-cigarettes does not eliminate an individual’s risk. In fact, exposure to these chemicals at various concentrations has been associated with cardiovascular, immune-related and respiratory diseases, and cancer.
Existing literature on the health risks of vaping has been criticised due to the fact that many subjects have a current or past history of smoking. This in turn complicates the interpretation of the results. Therefore, in order to understand the consequences of vaping, it is important to account for the confounding effects of prior smoking history.
Role for e-cigarettes in gene dysregulation
In a recent paper, published in Scientific Reports, researchers aimed to disentangle the biological effects of vaping while accounting for smoking as a potential confounder. By using RNA-sequencing, they constructed the whole transcriptome in leukocytes of adult e-cigarette users (with and without prior history of smoking), exclusively cigarette smokers and a control group of never-smokers and never-vapers. The team also performed biochemical analyses on the participants’ blood to verify the histories by measuring the concentration of cotinine (a breakdown product of nicotine).
Computational modelling revealed that current vaping, but not past smoking, is significantly associated with gene dysregulation in e-cigarette users.
Ahmad Besaratinia, corresponding author, explained:
“We found that more than 80% of gene dysregulation in vapers correlated with the intensity and duration of current vaping. Whereas none of the detected gene dysregulation in vapers correlated to their prior smoking intensity or duration.”
The team also found that, in both vapers and smokers, mitochondrial genes were preferential targets of gene dysregulation. Additionally, both these groups had significant dysregulation of immune response genes.
These findings support the growing evidence of the central role of the mitochondria in immunity and inflammatory responses, which are key to disease development. This study may also help inform the regulation of the manufacturing, distribution and marketing of e-cigarettes.
The team now hope to identify and investigate chemicals that are common to both cigarette vapour and cigarette smoke to find out which ones might be causing similar adverse effects these groups.
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