NanoRelease Food Additive Task Group 3 White Paper

1. - Alimentary Canal Models- NanoRelease Food AdditiveTask Group 3 White Paper Current Findings and Conclusions April 16, 2013 1 www.riskscience.org

2. Disclaimer The statements made in this presentation reflect the personal scientific opinion of the co-chairs and co-authors, and do not necessarily reflect the official position of any of the employers or organizations affiliated with the co-chairs and co-authors. The recommendations do not supersede applicable national legal risk assessment requirements. They will not necessarily be used as a basis for guidelines and/or recommendations issued by regulatory authorities. 2 www.riskscience.org

3. We aimed to prepare a review of alimentary canal models applicable for the assessment of the stability, kinetics, bioavailability and excretion of engineered nanomaterials following release from food. Task Group 3 - Aim www.riskscience.org

4. TG3: Alimentary Canal ModelsMEMBERS www.riskscience.org

5. Chapter 1: Introduction Chapter 2: Applicability of models of the healthy alimentary canal Chapter 3: Applicability of models for physiological and disease states of the alimentary canal Chapter 4: Specific examples of nanomaterial quantification in models of the alimentary canal Chapter 5: Discussion and Conclusions (100 pages) Table of Contents www.riskscience.org

6. In vivo • Ex vivo • In vitro Model Categories • In silico www.riskscience.org

7. Discussion of Findings The 3 categories can be studied in these systems • soft/lipid-based nanomaterials • solid non-lipid non metal nanomaterials • solid metalloid / metal-based nanomaterials • Several examples of each are available in the literature. No clear tendencies are yet apparent. Stability, kinetics, bioavailability and excretion rates can vary depending on specific nanomaterial surface chemistry, size, charge, etc. • Controls: ions, nanomaterials, bulk material www.riskscience.org

8. Recommendations on models of the alimentary canal for assessment of the stability, behaviour, bioavailability and excretion of nanomaterials following release from food 8 www.riskscience.org

9. TIER 1 Screen the nanomaterial in the following systems to quantify stability, solubility, agglomeration, and dynamics such as absorption and movement along the alimentary canal towards fecal excretion. • In silico computational models built on analytical data with similar nanomaterials – if such data is available for comparison • In vitro non-cellular digestive fluids to model conditions in the mouth, stomach, small intestine and/or large intestine 9 www.riskscience.org

10. TIER 2 Reconstruct healthy intestine using cells In Vitro: • Epithelial cells of the buccal cavity (mouth) • Intestinal Caco-2 enterocyte-like cells • Co-culture to generate intestinal M-cells • Co-culture with mucus-producing cells Some in vitro models can be adapted to reflect disease states. If a subpopulation of humans has a physiological state which modifies their ability to absorb nutrients or toxins, bioavailability could also be studied in these disease models. An alternative would be the use of inter-individual uncertainty factors. 10 www.riskscience.org

11. TIER 3 In Vivo studies in wild-type rodents and/or rodent models of human diseases. Use OECD oral exposure and toxicokinetic protocols. This tier could be important for engineered nanomaterials which will have high human exposure levels. An interspecies uncertainty factor is sometimes used to relate data in animals to human risk assessment. 11 www.riskscience.org

12. Notes on the Recommendations • Relevant models exist. However, the alternative models require standardization and validation before being acceptable for all stakeholders. • There likely won’t be a single method that addresses all of the necessary questions. 12 www.riskscience.org

13. Methods Development Needs • Development of analytical tools to quantify nanomaterial stability in complex media, saliva, chyme, feces and biological tissues; for assessment of the kinetics of food-borne nanomaterials • Validation of existing absorption and excretion models for use in risk assessment of nanomaterials (particularly confirmation that alternative ex vivo, in vitro and in silico models are reflective of animals and humans). 13 www.riskscience.org

14. Factors to consider in the selection of alimentary canal models for further development • reproducibility • ease of use • time required • easy access to required instrumentation, reagents and expertise • cost-effectiveness 14 www.riskscience.org

15. We are in the final stages of drafting • We are open to input from stakeholders on our suggested tiered approach to the selection of models of the alimentary canal Task Group 3 White Paper Status www.riskscience.org

16. Thank you for your attention! 16 www.riskscience.org