Sting for brain toxicity testing
30 December 2013. Good news, finally, and from an unexpected source. Just before the holidays, the EU agency responsible for food safety recommended detailed assessment of possible brain drain risks from the two “neonic” pesticides that we recently called attention to – acetamiprid and imidacloprid. The report from the European Food Safety Authority (EFSA) was triggered by a request from the European Commission to evaluate a Japanese study that these pesticides may affect so-called nicotinic acetylcholine receptors (nAChRs) in the nervous system. This seminal report has previously been highlighted here.
The two pesticides were recently banned temporarily in the EU due to their apparent toxicity to honey bees. Research carried out at the U.S. Environmental Protection Agency has also focused on the effect of the pesticides on honey bees, but no action has been taken so far in the U.S. In a statement to the New York Times, an industry spokesperson claimed that imidacloprid has no developmental neurotoxicity potential in humans and also raised questions about the Japanese study, as it “reports investigations in rat cell cultures, i.e. in an artificial system.” The EFSA experts are less dismissive in regard to the cell-based findings and recommend further research in this field. In fact, the particular brain receptors that are targeted by the neonicotinoids are of crucial importance to brain development – also in humans.
Not only that, but the EFSA experts also call for further consideration of toxic effects on brain development using recommended protocols for Developmental Neurotoxicity Testing (DNT), including call-based tests. EFSA is therefore proposing to define criteria that should trigger mandatory DNT studies as part of the pesticide authorisation process and perhaps also for other substances. This proposal would lead to a comprehensive testing strategy to evaluate the DNT potential of neonicotinoid pesticides and perhaps other chemicals that may cause adverse effects on brain development. The experts suggest a stepwise approach that uses laboratory tests on cells (so-called in vitro) as a first screening step and then progresses to tests on animals (in vivo) if the initial results raise concerns over the brain-draining potential of a substance.
This initiative – this well-argued sting – should be warmly welcomed and should inspire consideration also in regard to the forthcoming update of EU’s chemicals regulations (REACH).