We were looking to see whether we could have figured out that these babies were exposed in utero just by using the gene expression screening on the stored blood samples, Samson says. The answer was a resounding yes.
Further, the team found that a subset of just 11 of these genes could be used as a highly reliable test for determining whether babies had been born to mothers exposed to arsenic during pregnancy. Since blood samples are already taken routinely for medical tests this may provide an easier way of screening for such exposure.
The gene expression changes the group found in the exposed children are mostly associated with inflammation, which can lead to increased cancer risk. Recognizing the damaging effects of the arsenic exposure, the government has provided alternative water sources to the affected villages, Fry says, which means that following these children as they grow older (they are now toddlers) has the potential to show how long-lasting the effects of the prenatal exposure may be. However, she adds, this may be complicated by the fact that many people are still using the local water for cooking.
It's not yet clear how long the changes may last. We will be testing whether these gene expression changes have persisted in these children, Fry says.
This is the first time such a response to prenatal arsenic exposure has been found in humans. But it is not entirely unexpected, Samson explains, because in mice, when mothers are transiently exposed to arsenic in the drinking water, their progeny, in their adult life, are much more cancer-prone.
Further research could include studies of possible ways of reversing or mitigating the
|Contact: Elizabeth Thomson|
Massachusetts Institute of Technology