Innovative non-animal based testing platform to detect chemical-induced cardiotoxicity - A roadmap for regulatory uptake.

Accounting for 32% of all global deaths in 2019, cardiovascular diseases (CVDs) are the leading cause of mortality worldwide. However, the relationship between environmental chemical exposure and CVD development is poorly understood. Furthermore, current regulations do not address cardiotoxicity as a specific endpoint, resulting in ineffective prevention of CVD incidence and deaths caused by chemical exposures. With an aging population and chronic exposure to chemical mixtures, particularly in Europe, there is an urgent need to develop robust, non-animal based mechanistic strategies to assess the cardiotoxicity of chemicals. In this context, the Horizon 2020 project ALTERNATIVE (grant no. 101037090) aims to develop a non-animal test platform to detect the cardiotoxicity of chemicals . The platform includes a 3D in vitro physiological system mimicking healthy and aged human cardiac tissue, as well as multi-omics analyses and an integrated Machine Learning (ML) risk assessment tool. One of the main challenges is facilitating the regulatory uptake of this innovative platform in order to provide a more robust basis for decision-making. To facilitate regulatory uptake of the platform, we first reviewed existing cardiotoxicity regulations for chemicals, pesticides and biocides, and indicated how specific limitations in addressing the elderly population and chemical mixtures could be overcome using new approach methodologies (NAMs). The adverse outcome pathway (AOP) framework can provide mechanistic relevance for NAMs by identifying the mechanistic underpinnings of the toxicological responses observed in NAMs. Based on textbook knowledge, we have developed and introduced two putative AOPs leading to heart failure (AOP 479 and AOP 480) that are now included in the OECD workplan. Evidence from systematic reviews to support these AOPs is currently being assembled and assessed according to the OECD handbook. Finally, an AOP-informed integrated approach to testing and assessment (IATA) will be drafted by integrating existing knowledge and other IATA components developed within this project, such as the 3D in vitro system, QSAR models, and PBK modeling. The outcome is expected to provide a basis for a practical regulatory approach to assess the potential of chemicals to induce cardiotoxicity. Subsequently, our IATA will be proposed for common elaboration within the ASPIS cluster, OECD working groups and regulatory stakeholders/policy makers, aiming to integrate our IATA into a larger framework. A final guidance and strategy for validation will be drafted, which will be submitted to EURL ECVAM for review and to seek approval for further validation of this novel platform. Ultimately, we aim to improve the regulatory acceptance and uptake of NAMs for cardiotoxicity assessment, and contribute to the prevention of exposure to potential cardiotoxic chemicals.