Expert meeting ponders chemical testing in the 21st century
By Thaddeus Schug
Rapid advances in science are fueling an evolution in toxicity testing, from predominantly animal-based studies, to greater incorporation and reliance on 21st century predictive toxicology methods, such as rapid, high-throughput in vitro testing. These types of new tests are cheaper and faster, lessen use of laboratory animals, and hold the potential to help address practical limitations we face in assessing chemical exposures in the real world.
But will these new testing strategies, in fact, improve our ability to understand and predict chemical hazard and risk and, ultimately, better protect the public’s health? What advances have been made and what potential benefits and challenges do they present?
To help begin addressing these questions, the Environmental Defense Fund (EDF) convened a meeting, “Chemical Testing in the 21st Century: Opportunities and Challenges,” Jan 24-25 in Washington, D.C., with experts from government, industry, academia, and non-governmental organizations.
Faster and cheaper testing strategies
“Toxicology has come a long way in the past few decades, and we are now at the stage where we can discuss replacing traditional long-term animal testing protocols with cost-effective high-throughput assays,” said NIEHS/NTP Director Linda Birnbaum, Ph.D., in an impromptu welcome to participants. “We are developing reliable assays that can quickly and efficiently flag problematic chemicals,” she added.
Opening presentations reviewed some of the key regulatory and scientific factors motivating the development of new chemical testing approaches.
Scientists from EPA and NIEHS spent some time explaining how ToxCast and the multiagency Tox21 program aim to move forward in this direction, through utilization of state-of-the-art high-throughput acellular and cellular assays that probe interactions between chemicals and a wide range of biological processes.
“The Tox21 program is in the process of testing a battery of 10,000 chemicals to produce activity profiles,” explained NTP Biomolecular Screening Branch Chief Ray Tice, Ph.D. “Currently, the activity profiles from these compounds require complex analysis of many different assays but, very soon, the technology will exist to perform multiple, genomic-based assessments of cellular responses to chemicals that will provide a complete, integrated picture of biological response to chemicals.”
Considerations of validation, use, and communication
Sessions on day two of the meeting covered an array of important topics, including test validation and the ability of high-throughput tests to reflect real-world exposures; new tools for high-throughput exposure modeling; potential near-term and future applications of newer methods; and means for greater stakeholder and public engagement and communication in this area.
Over the course of the two days, many ideas and perspectives were shared. It is clear that there are many critical and complex issues that need to be addressed, as efforts to advance new chemical testing approaches are made. Meetings, like this one, with multiple stakeholders, are valuable forums for working through the major issues.
“The goal of this multistakeholder meeting was really twofold — to foster a better understanding of the development and direction of emerging approaches for evaluating chemical hazard and risk, and to begin sharing various perspectives on the critical issues shaping the future of chemical testing and assessment,” said Jennifer McPartland, Ph.D., meeting lead organizer and EDF health scientist.
(Thaddeus Schug, Ph.D., is a health scientist in the NIEHS Division of Extramural Research and Training and a regular contributor to the Environmental Factor.)