a novel hybrid tobacco product that delivers a tobacco flavour note with vapour aerosol (Part 2): In vitro biological assessment and comparison with different tobacco-heating products

Introduction:
This summary will provide an overview of a study that assessed the toxicological and biological responses of a novel hybrid tobacco product, as well as the comparison of these responses with those of different tobacco-heating products. The study used various exposure matrices, including total particulate matter (TPM), whole aerosol (Wa), and aqueous aerosol extracts (aqE) obtained after machine-puffing the test products under the health Canada Intense smoking regime. The levels of carbonyls and nicotine in these matrices were also measured to understand the aerosol dosimetry of the products.

Key Points:

* The hybrid tobacco product tested negative across various in vitro assays, including mutagenicity, genotoxicity, cytotoxicity, tumour promotion, oxidative stress, and endothelial dysfunction.
* all the ThPs tested demonstrated significantly reduced responses in these in vitro assays compared to 3R4F, suggesting their potential for reduced health risks.
* The aerosol from vapour products forms differently than cigarette smoke, with e-liquids containing nicotine, propylene glycol, vegetable glycerol, and flavoring agents, while ThPs generate aerosol from heated tobacco.
* The study compared the cytotoxicity, genotoxicity, and oxidative stress potential of the hybrid tobacco product, 3R4F, c-ThP, and p-ThP using various in vitro assays.
* The hybrid tobacco product and ThPs showed significantly less cytotoxicity than 3R4F at a common dose, and none of the alternative products induced DNa damage in the g-h2aX assay.
* The Bhas 42 cell transformation assay, which detects tumour promoting activity, showed that 3R4F TPM induced a concentration-dependent response, while ThPs and the hybrid tobacco product TPM were negative at all concentrations tested.
* additional in vitro endpoints relevant to disease processes, such as oxidative stress and endothelial wound repair, were also assessed, with the hybrid tobacco product showing little to no biological activity.

Main Message:
The study suggests that the novel hybrid tobacco product and ThPs have the potential for reduced health risks compared to conventional cigarettes. The findings support further pre-clinical and clinical assessments to substantiate the risk reduction of these novel products at individual and population levels. however, it is crucial to note that while these products may pose fewer health risks than traditional cigarettes, they are not risk-free, and their long-term effects on consumers require additional research.

Breheny, Damien, Jason adamson, David azzopardi, andrew Baxter, Emma Bishop, Tony Carr, Ian Crooks, et al. “a Novel hybrid Tobacco Product That Delivers a Tobacco Flavour Note with Vapour aerosol (Part 2): In Vitro Biological assessment and Comparison with Different Tobacco-heating Products.” Food and Chemical Toxicology 106 (august 2017): 533–46. https://doi.org/10.1016/j.fct.2017.05.023.