Researchers Craft Tool to Minimize Threat of Endocrine Disruptors in New Chemicals

The innovative “TiPED” testing system (Tiered Protocol for Endocrine Disruption) stems from a cross-disciplinary collaboration among scientists, and can be applied at different phases of the chemical design process. The goal of the system is to help steer companies away from inadvertently creating harmful products, and thus avoid adding another BPA or DDT to the marketplace.

A paper describing the work, “Designing Endocrine Disruption Out of the Next Generation of Chemicals,” is published online in the Royal Society of Chemistry journal Green Chemistry.

“In order to reduce our exposure to endocrine disruptors, we have to ensure that new products entering the market do not contain them,” says Dr. Heather Patisaul, an associate professor of biology at NC State and co-author of the paper. “The goal of this project is to develop an effective strategy for chemists, engineers, and manufacturers to identify potential endocrine disruptors before they are used in commercial products. Identifying these types of chemicals early in the design process will ultimately help ensure that we develop the safest products possible, which benefits consumers.”

The work was conducted by biologists, green chemists and others from North America and Europe who say that recent product recalls and bans reveal that neither product manufacturers nor governments have adequate tools for dealing with endocrine disrupting chemicals (EDCs). EDCs are chemicals commonly used in consumer products that can mimic hormones and lead to a host of modern-day health epidemics including cancers, learning disabilities and immune system disorders.

The authors conclude that as our understanding of the threat to human health grows, the need for an effective testing strategy for endocrine disrupting chemicals becomes imperative.

Historically, chemists have aimed to make products that are effective and economical. Considering toxicity when designing new chemicals has not been their responsibility. This collaboration between fields expands the scope of both biologists and chemists to lead to a way to design safer chemicals.

There is a companion website to the paper, www.TiPEDinfo.com. One can access the paper there and learn more about the TiPED system.

The paper was co-authored by researchers from NC State, NIEHS, the University of California, San Diego, the University of California, Irvine, Carnegie Mellon University, University of Texas at Austin, Virginia Commonwealth University, Advancing Green Chemistry, Louisiana Tech University, Medical University of South Carolina, University of California, Berkeley, McGill University, Oregon State University, Tufts University, the Warner Babcock Institute for Green Chemistry, the University of Texas Medical Branch, the University of Missouri–Columbia, the University of Massachusetts-Amherst and Environmental Health Sciences.

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Note to Editors: The study abstract follows.

“Designing endocrine disruption out of the next generation of chemicals”

Authors: T. T. Schug, R. Abagyan, B. Blumberg, T. J. Collins, D. Crews, P. L. DeFur, S. M. Dickerson, T. M. Edwards, A. C. Gore, L. J. Guillette, T. Hayes, J. J. Heindel, A. Moore , H. B. Patisaul, T. L. Tal, K. A. Thayer, L. N. Vandenberg, J. C. Warner, C. S. Watson, F. S. vom Saal, R. T. Zoeller, K. P. O’Brien and J. P. Myers.

Published: Dec. 6, Green Chemistry

Abstract: A central goal of green chemistry is to avoid hazard in the design of new chemicals. This objective is best achieved when information about a chemical’s potential hazardous effects is obtained as early in the design process as feasible. Endocrine disruption is a type of hazard that to date has been inadequately addressed by both industrial and regulatory science. To aid chemists in avoiding this hazard, we propose an endocrine disruption testing protocol for use by chemists in the design of new chemicals. The Tiered Protocol for Endocrine Disruption (TiPED) has been created under the oversight of a scientific advisory committee composed of leading representatives from both green chemistry and the environmental health sciences. TiPED is conceived as a tool for new chemical design, thus it starts with a chemist theoretically at “the drawing board.” It consists of five testing tiers ranging from broad in silico evaluation up through specific cell- and whole organism-based assays. To be effective at detecting endocrine disruption, a testing protocol must be able to measure potential hormone-like or hormone-inhibiting effects of chemicals, as well as the many possible interactions and signaling sequellae such chemicals may have with cell-based receptors. Accordingly, we have designed this protocol to broadly interrogate the endocrine system. The proposed protocol will not detect all possible mechanisms of endocrine disruption, because scientific understanding of these phenomena is advancing rapidly. To ensure that the protocol remains current, we have established a plan for incorporating new assays into the protocol as the science advances. In this paper we present the principles that should guide the science of testing new chemicals for endocrine disruption, as well as principles by which to evaluate individual assays for applicability, and laboratories for reliability.

In a ‘proof-of-principle’ test, we ran 6 endocrine disrupting chemicals (EDCs) that act via different endocrinological mechanisms through the protocol using published literature. Each was identified as endocrine active by one or more tiers. We believe that this voluntary testing protocol will be a dynamic tool to facilitate efficient and early identification of potentially problematic chemicals, while ultimately reducing the risks to public health.