James Bruckner, a toxicology professor in the College of Pharmacy, received a two-year, $898,179 contract from the Consumer Specialty Production Association to assess potential neurotoxic risks posed by pyrethroid insecticides to infants and children. The research findings will be forwarded to the U.S. Environmental Protection Agency so it can develop scientifically based exposure guidelines to assure safe levels of pyrethroids in agriculture and the home.
The Consumer Specialty Production Association is a consortium of 18 chemical companies that manufacture and/or sell pyrethroid insecticides.
“When the EPA banned the use of neurotoxic DDT and organophosphates as insecticides, it forced chemical companies to switch to pyrethroids without having established scientific guidelines for their safe use,” Bruckner said.
Relatively little is known about how the body handles or responds to most pyrethroids, particularly in infants and children.
“Generally, infants and young children are incapable of detoxifying high doses of chemicals, but the high-dose experiments performed in the past often may not be relevant to lower real-life doses,” he said.
Experiments are planned to test the hypothesis that young rodents and humans have adequate amounts of plasma and liver enzymes to deactivate all of the very low environmentally relevant doses of pyrethroids. This should result in comparable, nontoxic brain levels in all age groups, he said.
Bruckner’s interdisciplinary research team, made up of Michael Bartlett, Brian Cummings, Cathy White and Jason Zastre from the department of pharmaceutical and biomedical sciences, will focus on understanding gastrointestinal absorption, plasma protein and lipoprotein binding and blood-brain-barrier permeability of select pyrethroids. Experiments will be conducted in mature rats, cultured human cells and blood from children and adults to learn whether the chemicals are actively carried across gastrointestinal and blood-brain-barrier membranes by transport proteins.
The results, Bruckner said, will be used to develop and assess the ability of physiologically based pharmacokinetic computer models to accurately forecast blood and brain pyrethroid concentrations in people of different ages. Validation of physiologically based pharmacokinetic models provide a scientifically based alternative and an indirect means of predicting target organ levels and resulting adverse effects of toxic chemicals in infants, children and adults for realistic insecticide exposure scenarios.
