Wednesday, July 15, 2015

New Study Finds that E-Cigarettes Have No Adverse Effect on Respiratory Epithelial Cells, While Tobacco Smoke Kills the Cells

A new study conducted by British American Tobacco and published in the journal Toxicology in Vitro reports that e-cigarette aerosol from two conventional products had no adverse effect on human respiratory epithelial cells (in cell culture), while tobacco smoke caused almost complete cell death.

The methods and results are summarized as follows: "EpiAirway™ tissues [in vitro respiratory epithelial cells in culture] were exposed to cigarette smoke and aerosol generated from two commercial e-cigarettes for up to 6 h. Cigarette smoke reduced cell viability in a time dependent manner to 12% at 6 h. E-cigarette aerosol showed no such decrease in cell viability and displayed similar results to that of the untreated air controls. Applicability of the EpiAirway™ model and exposure system was demonstrated, showing little cytotoxicity from e-cigarette aerosol and different aerosol formulations when compared directly with reference cigarette smoke, over the same exposure time."

According to a British American Tobacco press release: "Until now, there have been no aerosol studies of potential adverse effects of e-cigarette vapour on in vitro models that so closely mimic the structure, function and exposure of normal human airway tissue. The researchers combined a commercially available 3D model of respiratory epithelial tissue and the popular VITROCELL smoking robot, an aerosol exposure system, to assess the irritant potential of e-cigarette vapour from two commercially available e-cigarettes on human airway tissue. The results show that, despite hours of aggressive and continuous exposure, the impact of the e-cigarette vapour on the airway tissue is similar to that of air."

The overall conclusion of the study was as follows: "Further studies will need to be conducted to compare between different commercially available products, formats,and formulations, but our data suggest that e-cigarette aerosols have significantly less impact than cigarette smoke over the duration of a 6 h exposure in vitro using organotypic tissue constructs."

The two products tested were NJOY Bold and NJOY Menthol.

The Rest of the Story

While one cannot necessarily extrapolate from this study to all e-cigarette products, at least we now know that one major brand of electronic cigarettes appears to have relatively benign effects on the cells lining the respiratory tract, in contrast to cigarette smoke which exhibits very high levels of cytotoxicity. This finding is consistent with earlier studies showing that the aerosol produced by NJOY e-cigarettes did not contain measurable quantities of most of the chemicals of concern that have been detected in the aerosol produced by some e-cigarette brands.

A major contribution of this research is that it sets out a procedure that could be used to test the cytotoxicity of various brands of electronic cigarettes, providing some assessment of the potential for respiratory irritation or inflammation that could be associated with these products. It could also help the FDA identify manufacturing procedures and/or quality control measures that prevent the formation of the unwanted chemicals in e-cigarette vapor, which could aid the agency in crafting quality standards to ensure that e-cigarettes on the market are as safe as they can be.

Despite the limitations of the research, it adds additional evidence to support the contention that vaping is a lot safer than smoking. Moreover, it suggests that it is possible to produce an e-cigarette that has little cytotoxicity to respiratory epithelial cells.

I am by no means an expert on e-cigarette design, but I can't help but think that the careful voltage and temperature regulation that the tobacco companies and the large independent e-cigarette companies have built into their products have a great deal to do with the fact that the aerosol produced by these products appears to present few concerns about the chemicals present or about the aerosol's cytotoxicity. Overheating is likely a major reason why some products have been found to produce an aerosol that does contain a number of toxins, such as various aldehydes.

This research adds to the evidence suggesting that with proper regulation, the FDA could maximize the potential benefits of e-cigarettes while minimizing their potential harms. If embraced by the agency, e-cigarettes have the potential to transform the nicotine market and produce a dramatic shift away from combustible tobacco products (i.e., cigarettes) and toward non-combusted, non-tobacco-containing e-cigarettes. Such a phenomenon would result in the greatest public health miracle of our lifetimes.

Unfortunately, I do not believe that the anti-tobacco groups or major health agencies, including the CDC or the FDA, are aiming to try to transform the nicotine market and achieve this huge public health victory. Instead, they are taking a zero-risk, zero-addiction approach that is ideal in a fantasy world, but destructive to the public's health in the real world.

1 comment:

Blogger said...

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