Houston to Lead Study of Toxin Effects on Embryos

Thanks to a $3.2 million grant from the Environmental Protection Agency (EPA) and its Science to Achieve Results (STAR) program, a group of University of Houston researchers is taking the lead with about $1.5 million in a collaboration involving the Texas A&M Institute for Genomic Medicine and Indiana University. The other two research groups were awarded about $750,000 each for their contributions.

The primary aim of the three-year grant is to contribute to a more reliable chemical risk assessment that will provide clues to how certain chemicals affect human health. This will provide researchers with a wealth of new information about what toxins may cause serious diseases. Examples may be embryos exposed to chemicals that reduce the number of brain stem cells or change the number of neurons resulting in a greater risk of developing neurodegenerative diseases in adulthood, such as Parkinson's and Alzheimer's disease, as well as detecting developmental effects like spina bifida, one of the most common birth defects.

A new virtual center has been assembled through EPA to analyze the effects of many of these toxic chemicals on the developing embryo. Initiated by the Center for Nuclear Receptors and Cell Signaling (CNRCS) at UH, the new entity is called the Texas-Indiana Virtual STAR (TIVS) Center.

A main goal of this multidisciplinary research will be to include finding ways to speed up the testing process and decrease the costs. This can be done through the use of zebrafish in the studies to be performed at UH, which is a new approach that will complement Texas A&M's use of mouse embryonic stem cells in this project. While it can be argued that, as mammals, mice are closer to humans, they are much more costly. Furthermore, zebrafish can be exposed to several toxins at once, more realistically representing the world in which we live.

There are a number of similarities between fish and mammals with regard to developmental pathways, and about 75 percent of their genes are the same.

The researchers say current chemical regulations are insufficient, and the environmental and public health implications of toxin exposure have not been fully determined for the vast majority of chemicals, with a considerable knowledge gap remaining between exposure and effects. Therefore, a need to restructure the risk-assessment procedure is necessary to protect future generations.

A main objective of TIVS is to contribute to a more reliable chemical risk assessment through developing increasingly effective screening models of developmental toxicity. By incorporating the collective results and subsequent computer models developed during this research project into other screening projects that are being performed in the United States and Europe, researchers will be able to better prioritize chemicals for further risk assessment, with new methods for the screening of developmental adverse effects in zebrafish and mouse embryonic stems cells that are relevant for human embryonic development.

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