MIT: Prenatal arsenic exposure detected i...( CAMBRIDGE Mass MIT researchers have...)

CAMBRIDGE, Mass MIT researchers have found that the children of mothers whose water supplies were contaminated with arsenic during their pregnancies harbored gene expression changes that may lead to cancer and other diseases later in life. In addition to establishing the potential harmful effects of these prenatal exposures, the new study also provides a possible method for screening populations to detect signs of arsenic contamination.

This is the first time evidence of such genome-wide changes resulting from prenatal exposure has ever been documented from any environmental contaminant. It suggests that even when water supplies are cleaned up and the children never experience any direct exposure to the pollutant, they may suffer lasting damage.

The research will be reported in the Nov. 23 issue of PLoS Genetics (published by the Public Library of Science).

The evidence comes from studies of 32 mothers and their children in a province of Thailand that experienced heavy arsenic contamination from tin mining. Similar levels of arsenic are also found in many other regions, including the US Southwest.

The research was led by Mathuros Ruchirawat, Director of the Laboratory of Environmental Toxicology of the Chulabhorn Research Institute (CRI) in Thailand, and Leona D. Samson, Director of MITs Center for Environmental Health Sciences (CEHS) and the American Cancer Society Professor in the Departments of Biological Engineering and Biology at MIT. The first author of the study is Rebecca C. Fry, a research scientist at CEHS. Coauthors include Panida Navasumrit of the CRI and Chandni Valiathan, graduate student at MITs Computational and Systems Biology Initiative.

The team analyzed blood that had been collected from umbilical cords at birth. The exposure of mothers to arsenic during their pregnancy was independently determined by analyzing toenail clippings the most reliable way of detecting past arsenic exposure.

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