A total of 29 participants from 12 countries (Belgium, Croatia, Denmark, Germany, Greece, Italy, Norway, Slovakia, Slovenia, Sweden, Switzerland, United Kingdom) gathered at the Institute of Environmental Medicine (IMM), Karolinska Institutet ↗, Stockholm, Sweden, for the PARC in-person training course on Adverse Outcome Pathways (AOPs) – Principles and Applications. Held from 3 to 7 November 2025, the course was organised under the first PARC training cycle and focused on equipping researchers and professionals with the theoretical foundations and practical skills to develop, assess, and apply AOPs in toxicological research and risk assessment.

The programme featured a combination of expert-led lectures, interactive discussions, and group assignments. Over five days, participants delved into AOP networks, regulatory applications, and links to Integrated Approaches to Testing and Assessment (IATAs). Sessions were delivered by experts from Karolinska Institutet ↗, European Food Safety Authority (EFSA) ↗, University of Antwerp (UAntwerp) ↗, EU Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM) ↗, and the Norwegian Institute for Water Research (NIVA) ↗.

The course successfully brought together participants with a strong interest in developing and applying AOPs to advance mechanistic research and risk assessment. A well-balanced combination of presentations, group assignments, and interactive discussions fostered effective learning and provided excellent opportunities for networking, noted Johanna Zilliacus, scientific coordinator.

Participants appreciated the structured and application-oriented format. Group assignments allowed them to analyse real scenarios, propose solutions, and apply AOP principles in collaborative settings. Topics such as the development of AOPs for skin sensitisation, their quantitative application, and their role in EFSA’s regulatory work were explored through case-based learning and discussion.

Feedback from participants was overwhelmingly positive. 

A very inspiring, informative, and well-organised course. The structure, with the mix of presentations and group work, was a great way to deepen knowledge about AOPs.

This was an amazing course. The organisation was very smooth, and the exact right amount of knowledge was shared in the lectures.

Great course that was structured very well, with excellent presentations and presenters. I really liked the small group assignments because of all the discussion and explanations.

This course is a very comprehensive introduction to AOPs, from development to application.

With its focus on connecting mechanistic understanding to real-world applications, this training contributed to PARC’s broader mission to build capacity specifically for non-animal approaches and to strengthen the scientific basis of chemical risk assessment across Europe.

Stay tuned to the PARC website for information on upcoming training courses, open learning resources, and related materials.