Federal scientists are collaborating on a new approach to testing the toxicity of chemicals ranging from pesticides to household cleaners. They plan to use new automated high-speed cell tests to get more reliable data faster and more cheaply, and with less reliance on animal testing.
The National Institutes of Health and the U.S. Environmental Protection Agency are partners in the plan. NIH director Elias Zerhouni says scientists will apply technology developed by the two agencies to identify chemicals that might be harmful to humans.
"You could, in a battery of tests, end up with very specific molecular signatures that will be predictive of human toxicology, in ways that you just can't do in animal testing today," he said.
Scientists now rely heavily on animal tests to generate chemical toxicity data. That process is expensive, time-consuming and not always the best predictor of effects on humans says Francis Collins, director of the NIH National Human Genome Research Institute.
"There are differences between species. We are not rats and we are not even other primates, and so that [the] desire here is to see if we could do better," she said. "Ultimately what you are looking for is [whether] this compound does damage to cells."
The high-speed automated screening looks at the effects of chemical compounds on single human cells rather than on an entire laboratory animal. Researchers expect the new toxicology testing method will expand the number of chemicals tested and reduce the time, money and use of animals. NIH director Elias Zerhouni says it will also generate data more relevant to humans.
"What is being proposed here is to move the 20th century paradigm of testing of one compound at a time in many animals to going to the 21st Century paradigm [that] tests 5,000 to 10,000 compounds against 20,000 conditions in cells that are very specific to human toxicology," he said.
Since NIH started the National Toxicology Program 30 years ago, it has tested 2,500 chemicals. Using the new automated strategy could get the same job done in a single afternoon.
John Butcher, associate director of the National Toxicology Program, explains that to check the reliability of this approach, scientists will first do a comparative analysis of the 2,500 chemicals previously tested on animals.
"And we can compare the output from these cell-based assays, in terms of whether these chemicals cause cancer, reproductive and developmental effects, neurological effects, immunotoxic effects and various other kinds of toxicity," he said.
Butcher says the anticipated shift away from animal testing could take many years. Writing in Science Magazine, he says the agencies expect broader participation from public and private partners in the scientific community as the cell-based testing methods are refined and accepted.