Key challenges for in vitro testing of tobacco and next generation products for regulatory applications: Recommendations for the Ames test

The Ames bacterial mutagenesis assay (Ames test) has been used for more than 50 years, to help assess the safety of a variety of single chemicals and complex mixtures in the form of solids, liquids or aerosols. Because of the diverse range of substances that need to be tested, many modifications of this test, as well as modifications of the methods by which the test substances are prepared and applied to the bacterial test system, have been developed. Currently, there is a need for mutagenicity testing of both traditional tobacco products and next generation products (NGPs) such as e-cigarettes, heated tobacco products, tobacco-free nicotine products, oral pouches, etc. There are currently no standardised guidelines that cover the differing, often complex, procedures used by different laboratories to assess NGPs with the Ames test. To address this problem, the Institute for In Vitro Sciences (IIVS) convened a workshop, where representatives of industry, government, academia, contract research organisations (CROs) and non-government organisations (NGOs) could present bespoke experimental techniques and data from their testing platforms. The further aim of the workshop was to help formulate some general guidelines that could be used in the testing of tobacco and nicotine products, to allow better comparisons to be made between laboratories. The workshop discussions also resulted in the identification of some suggested areas for future research activities.