CORESTA Meeting, Smoke Science/Product Technology, 2017, Kitzbühel, STPOST 21

The use of in vitro human biomarkers from relevant primary cell lines, to assess the effects of increasing nicotine concentration in e-liquids

(1) Imperial Tobacco Ltd, Bristol, U.K.; (2) DiscoverX Corporation, Fremont, CA, U.S.A.; (3) Fontem Ventures B.V. (an Imperial Brands PLC Company), Amsterdam, The Netherlands

As part of the ongoing stewardship of electronic cigarettes, and in line with the National Academies of Sciences “Toxicity Testing in the 21st Century: A Vision and a Strategy”, Fontem Ventures B.V. have investigated the utility of a series of endpoints in human primary cells. In the first instance, base e-liquids were used to determine the suitability of the test system.

DiscoverX Corporation, is a leading supplier of cell-based assays and services for drug discovery and development. The BioMAP® product was chosen, consisting of 12 primary human cell-based systems from multiple tissues. Cells are cultured either alone or as co-cultures and stimulated with a combination of biological proprietary factors (e.g. cytokines, growth factors, mediators, etc.) to recapitulate the multi-component signalling networks associated with disease states. The Diversity PLUS panel consists of 148 biomarker readouts and has been used as a tool for phenotypic drug discovery, competitive analysis and comparison to clinical standards of care.

Initial results of a base e-liquid (BL) containing only 50:50 propylene glycol and vegetable glycerine; BL containing 2.5 % nicotine and BL with a content of 4.5 % nicotine were tested at eight concentrations ranging between 0.031 to 4 % added directly to the cell media. BL with nicotine added to cell media at concentrations above 0.5 % lead to a characteristic fingerprint of biomarkers and showed a good dose response relationship with increasing concentration. This lead to an exaggeration of the fingerprint profile in selected cell panels, above that for the base e-liquid itself. The most sensitive cell panel in all cases was found to be the BT cell line composed of B cell and peripheral blood mono nuclear cells.

The results demonstrate that the use of BioMAP® is a sensitive and powerful tool, capable of detecting the addition of nicotine to e-liquids in a panel of human relevant primary cell lines. The next step is to assess the e-liquid aerosol, following stability trials of aerosol trapped in phosphate buffered saline.