If we can map the adverse outcome pathways of numerous molecules in the way that we have here, we will be able to develop models which mean you don’t have to administer products in vivo and then look for a reaction to establish whether or not they are safe.
- Tim Allen
A new approach to mapping and predicting the impact of chemical compounds in the body, which it is hoped could eventually reduce the need for toxicity tests in animals, has been trialed by scientists.
Although still at an early stage, the process involves identifying “molecular initiating events” (MIEs) - the term given to the moment at which a molecule that has entered the body starts to interact with it, kick-starting a sequence of events which leads to a toxic outcome.
By identifying the specific features and properties within individual molecules that cause these events, the researchers argue that it should be possible to make accurate predictions about the effects of new and untested chemical compounds with similar characteristics.
In principle, that would reduce the need to test some chemicals contained within drugs, pesticides, food additives or other consumer products on animals. Instead, scientists would be able to screen a chemical’s molecular structure using customised computer software - a transition they characterise as one from testing “in vivo” (within the living) to “in silico” (on computers).
To prove the point, the new research, reported in the journal Chemical Research in Toxicology, mapped the pathways by which several well-known compounds, such as paracetamol, cause toxic outcomes. By tracing these back to the molecular initiating event, the team were able to identify chemical characteristics, that were present in other molecules exhibiting the same toxicities.
Tim Allen, a PhD researcher in chemistry at St John’s College, University of Cambridge, and the paper’s first author, said: “We are at the very early stages of building predictive tools for different molecules, and this work provides a proof-of-concept foundation for doing much more.”
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Image: By tracing the pathway by which paracetamol becomes toxic in the body back to a single molecular initiating event, researchers were able to predict with accuracy the likely toxic effects of other compounds with similar molecular features.
Credit: Painkillers by David Pacey from Flickr
Reproduced courtesy of the University of Cambridge
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