Science1 publisher2 min readPublished
UFZ and Food Packaging Forum pick 15 bioassays from a network of 266 disease pathways
Sarah Stevens and colleagues mapped 266 adverse outcome pathways across six disease groups, then chose assays at the points where those pathways converge. Whether the assays catch known hazardous chemicals is the next study.
The Scientist · Science desk
What happened
- Researchers at UFZ and the Food Packaging Forum mapped 266 adverse outcome pathways onto six disease groups, among them cancer, metabolic disease, cardiovascular disease and brain-related disorders.
- Treating the pathways as networks, they picked 15 high-throughput in vitro bioassays meant to test whether a product already on the market could contribute to any of those six groups.
- The panel is not validated: the authors say the next step is determining how effectively the assays flag known hazardous chemicals, and a study on food-contact chemicals is already running.
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Why it matters
- capability Reading a material's biological activity would bring the unidentified non-intentionally added substances in food packaging within reach of testing. Testing built around named substances cannot get to compounds nobody has identified.
- constraint The panel is built for hazard identification. Anyone deciding whether a packaging material is acceptable still needs exposure and dose information that these assays do not produce.
- decision The regulators and industry stakeholders inside CoModHaz would have to accept in vitro endpoints beyond genotoxicity before a 15-assay result changes what any company is obliged to test.
- precedent If the food-contact validation study shows the assays catch hazards already on record, choosing assays by where pathways converge becomes a method other product categories can copy.
Fifteen assays standing in for 266 pathways is about 18 pathways per assay [15]. That compression is the design. The researchers mapped the 266 adverse outcome pathways onto six disease groups, then treated them as networks to locate the biological events where pathways converge and where a single event can help promote more than one disease [3][4]. Where many pathways run through one shared event, one assay can report on many pathways at once. Centrality in that network is a property of the 266 pathways that were mapped [4].
The approach targets hazard identification [2]. A hit says a sample can trigger an event the network ties to one of the six groups: cancer, reproductive disorders, metabolic disease, immunological disorders, cardiovascular disease and brain-related disorders [3]. How much of the chemical reaches a consumer is a separate question.
The authors name one use: packaging already on sale [8]. A food-contact material can carry non-intentionally added substances that nobody has identified, and so nobody has tested them [8]. A bioassay panel skips the names; it is meant to test whether the product itself is toxic and could contribute to any of the six groups in consumers [5]. Most chemicals in consumer products, packaging included, lack the data to say whether they are safe [7].
None of the 15 has been validated for this job. The next step is to determine how effectively they flag chemicals already known to be hazardous, and a study applying the approach to food-contact chemicals from packaging is under way [9]. Sarah Stevens, the lead author, at the Helmholtz Centre for Environmental Research, said: "The proposed panel of 15 assays could enable much broader toxicological screening of chemicals than is currently standard practice." [13]
By the source's account the gap is real: many testing requirements ask only about genotoxicity and examine one substance at a time, while consumers meet complex mixtures from many types of products simultaneously [6]. What this study does is widen the list of endpoints. Screening mixtures is a stated goal of CoModHaz, the co-creation project the work sits in, which is led by professor Escher of UFZ and covers chemicals, their transformation products and mixtures [10]. Regulators and industry stakeholders are partners in that project alongside the Food Packaging Forum [11].
Jane Muncke, a co-author from the Food Packaging Forum, said: "This research is an important milestone in improving the way we test chemicals." [14] The authors describe the proposed tests as a starting point that can evolve as new knowledge and testing technology become available [16].
What to watch
- The validation numbers: how many known hazardous chemicals the 15 assays flag, and how many they miss.
- Whether the food-contact study tests packaging extracts and mixtures or reverts to single compounds.
- Whether any regulator in CoModHaz writes non-genotoxicity in vitro endpoints into a testing requirement.