Reducing the Burden on Animals and the Heart: An Evidence-Based Approach to Cardiotoxicity Assessment.

Cardiovascular disease, which is the leading cause of mortality worldwide, is suggested to besignificantly exacerbated by environmental factors such as chemicals. However, current regulatory guidelines insufficiently assess the cardiotoxicity of chemicals, biocides, and pesticides and heavily rely on animal testing.Within the EU Horizon 2020 Project ALTERNATIVE, we aim to facilitate improved regulatory assessment of cardiotoxicity by identifying current regulatory limitations, collecting and integrating multiple lines of evidence for heart failure caused by environmental chemicals to develop an Adverse Outcome Pathway (AOP) framework, evaluating the weight of evidence according to OECD guidance, identifying suitable non-animal methods and Biomarkers of Effect (BoEs) to assess key events of the AOP, drafting of an Integrated Approach to Testing andAssessment (IATA).We identified insufficient assessment of cardiotoxicity, low predictivity of animal-based as well as in vitro methods used in current regulatory guidelines for cardiotoxicity, and the need to address the elderly population and mixtures. We developed a novel AOP network (including AOPs #479 & #480) that causally combines and integrates epidemiological human health evidence (15 studies), as well as experimental in vivo, and in vitro evidence (360 studies) from our systematic reviews on heart failure caused by environmental chemicals. The weight of evidence is evaluated using OECD guidance and omics analysis will be used to validate key events and identify corresponding BoEs.These AOPs will ultimately provide a foundation to an IATA for organ toxicity, includingcardiotoxicity, and reduce the dependence on animal testing.