Methods and Protocols

      The Ames Assay and assessment of Reduced-Risk Products

      PMI

      Published on
      May 1, 2017
      Topic
      Summary

      The Ames Assay (or Bacterial Reverse Mutation Assay) is the most commonly used in vitro genotoxicity test and was designed to detect genetic damage and gene mutations induced by a range of single chemicals and complex environmental and biological mixtures[1].

      The test is recommended by the Organisation for Economic Co-operation and Development (OECD) and the International Conference on Harmonisation (ICH) as part of the standard testing set for genotoxicity[2][3].

      Ames Assay to assess Reduced-Risk Products

      The Ames Assay can discriminate the mutagenic activity of total particulate matter (TPM) from different types of cigarette with different filter ventilation, filter efficiency and paper porosity[4][5]. It can also discriminate between tobacco types and cigarette smoke fractions[6] as well as between cigarettes and Reduced-Risk Products (RRPs).[4]

      We perform the Ames test in compliance with OECD guideline 471[2], taking into account that TPM is known to be mutagenic. In each test, concurrent positive and negative controls are evaluated and used to confirm the test performance.

      As can be seen in the graph below, we tested a range of doses of TPM from our RRP Platform 1 (regular and menthol) and 3R4F[7]. The graph very clearly shows that even at concentrations of TPM significantly higher than the maximum dose of TPM from 3R4F, the number of mutation revertants found in the bacteria exposed to TPM from Platform 1 was significantly reduced. 

       

      Genotoxicity in bacterial cells substantially decreased compared to 3R4F Note: these data alone do not imply or represent a claim of reduced exposure or reduced risk.

      References:

      [1] Maron, DM and BN Ames. Revised methods for the Salmonella mutagenicity test. Mutat Res, 1983. 113(3-4): p. 173-215. Available online at: https://www.sciencedirect.com/science/article/abs/pii/0165116183900109

      [2] OECD. OECD guideline for the testing of chemicals: bacterial reverse mutation test. 1997.

      [3] International Conference on Harmonisation. Guidance on genotoxicity testing and data interpretation for pharmaceuticals intended for human use. 2011.

      [4] Roemer. E, et al. Discrimination of cigarette mainstream smoke condensates with the Salmonella reverse mutation assay. The Toxicologist, 1998. 42(1-S): p. 295.

      [5] Tewes. FJ, et al. Cigarette parameters that influence the mutagenicity of mainstream smoke condensate. The Toxicologist 1999. 48(1-S): p. 296.

      [6] DeMarini, DM. Genotoxicity of tobacco smoke and tobacco smoke condensate. Mutat Res, 1983. 114(1): p. 59-89. Available online at: https://www.sciencedirect.com/science/article/abs/pii/0165111083900192 [

      [7] Philip Morris International Investor Day Presentation, 26 June 2014. Available online at: https://www.pmi.com/resources/docs/default-source/pmi-investor-day-archives-2016/2014-day-1/2014-06-26-rrps_investor_day_slides_-website_final-(2).pdf?sfvrsn=b4e092b5_4

      PMIScience.com is operated by Philip Morris International for the purpose of publishing and disseminating scientific information about Philip Morris International’s efforts in support of its smoke-free product portfolio. This site is a global site for use by scientists, the public health and regulatory communities, and other stakeholders with an interest in tobacco policy. The purpose of this site is not advertising or marketing, nor is it directed at any specific market. It is not intended for use by consumers. New tobacco products sold in the United States are subject to FDA regulation; therefore the content of this site is not intended to make, and nor should it be construed as making, any product related claims in the United States without proper FDA authorization. ​
      ​
      Reduced Risk Products ("RRPs”) is the term we use to refer to products that present, are likely to present, or have the potential to present less risk of harm to smokers who switch to these products versus continuing smoking. PMI has a range of RRPs in various stages of development, scientific assessment and commercialization. All of our RRPs are smoke-free products that deliver nicotine with far lower quantities of harmful and potentially harmful constituents than found in cigarette smoke.