Next generation product aerosols induce lower biological activity than combusted cigarettes: a comparison of in vitro cell migration in the scratch wound assay
Smoking combustible cigarettes is a cause of serious diseases in smokers, including heart disease. There are many commercially available next generation products (NGPs), such as tobacco-free e-vapour products, aiming to provide an alternative to smoking with a significant reduction in harm. The study aimed to compare the cardiovascular-related effect of NGP aerosol to cigarette smoke using the in vitro endothelial migration (scratch wound) assay.
Products investigated were the Kentucky reference cigarette (3R4F), a tobacco heating product (THP), a hybrid product (HYB) and a myblu™ e-vapour product (Tobacco Flavour 1.6 % Nicotine). The 3R4F and THP were smoked using an intense smoking regime, with HYB and myblu™ vaped according to CORESTA Recommended Method No. 81. Freshly generated smoke and aerosols were captured in phosphate buffered saline and added at concentrations up to 10 % of total cell media. Artificial wounds 700-800 µm wide were created in the human umbilical vein endothelial cell monolayer using a WoundMaker™ device. The impact of the test articles on endothelial cell migration activity was determined over 30 hours following exposure.
The scratch wound assay showed significant differences in rate of wound closure between test articles. A highly significantly, dose-dependent increase in wound closure inhibition was observed following 3R4F exposure. Trapped HTP and HYB aerosols showed lower migration activity over control indicating slight inhibition of the wound healing activity. The Dunnett’s multiple comparison test confirmed statistically significant effects for the HTP only. Trapped myblu™ aerosol did not show any significant inhibition of cell migration over control, even at the highest concentrations, under the conditions of test.
The data demonstrates clear differences between 3R4F smoke and next generation product (NGP) aerosols on endothelial cell migration, with no measurable effect observed for the tobacco-free myblu™ e-vapour product. These findings add to the increasing body of scientific evidence supporting the harm reduction potential of NGPs.