PhD Defence by Andreas Treschow

Principal supervisor:

• Prof. Anne Marie Vinggaard, DTU Food

Co-supervisor:

• Post doc Maria João Valente, DTU Food

Examiners:

• Prof. Jens Jørgen Sloth, DTU Food
• Prof. Johan Lundquist, SLU, SE
• Ass. prof. Martin Roursgaard, KU, DK

Chairperson at defence:

• Ass. prof. Martin Frederik Laursen, DTU Food

Resume
Everyday, we are exposed to numerous chemicals stemming from our environment, food and personal care products. This exposure might cause multiple harmful health effects. One area of particular concern for risk assessment of chemicals is the impact of this continuous exposure on the developing fetus in the womb. Current methods for testing for developmental toxicity of drugs and chemicals rely on animal models, which can misrepresent human adverse effects. For a more accurate chemical risk assessment in the future, it is important to develop highly predictive screening models, that are more human relevant and thus do not rely on the use of animals.

This Ph.D. thesis revolves around the PluriLum assay, a human stem cell-based method developed for embryotoxicity testing of chemicals in vitro. To further the field of development of the so-called ‘New Approach Methodologies’, or NAMs, we investigated the applicability of this assay in regard to identification of embryotoxic potential of single chemicals from different classes and performed a protocol optimization to improve the robustness and predictive power of the assay. Additionally, the assay was tested as a tool for screening mixture effects, for both defined chemical mixtures, namely of PFAS as chemicals of emerging concern, as well as complex chemical mixtures from ‘real-life’ samples, extracted from the water treatment pipeline, food items and human biological samples. Finally, the assay was used to investigate the modes of action by which PFAS may exert their embryotoxic effects through RNA sequencing analysis.

The PluriLum assay was able to correctly identify the embryotoxic potential of 4 out of 5 compounds with known teratogenicity, and further detect effects from three PFAS and two fungicides. The assay also proved to be a good tool to monitor relative potency of effects of both complex chemical mixture extracts, and defined PFAS mixtures. Lastly, the transcriptome analysis suggested that the tested PFAS broadly affect similar targets and functional pathways in the PluriLum assay.

The work presented in this thesis substantiates the future use of the PluriLum assay as part of batteries of in vitro assays to assess embryotoxic effects of single chemicals and mixtures, within the context of both science and industry, or as a part of a defined approach for regulatory assessment of developmental toxicity.

A copy of the PhD thesis is available for reading at the department.