WWII Chemical Exposure May Pass Down Disease, Study Finds

The World War II generation may have
passed down to their grandchildren the effects of chemical
exposure in the 1940s, possibly explaining current rates of
obesity, autism and mental illness, according to one researcher.

David Crews, professor of psychology and zoology at the
University of Texas at Austin, theorized that the rise in these
diseases may be linked to environmental effects passed on
through generations. His research showed that descendants of
rats exposed to a crop fungicide were less sociable, more obese
and more anxious than offspring of the unexposed.

The results, published today in the Proceedings of the
National Academy of Sciences, are part of a growing field of
study that suggests environmental damage to cells can cause
inherited changes and susceptibility to disease. Crews said his
findings are applicable to humans.

“This, I think, is the first causal demonstration that
environmental contamination may be the root cause of the great
increase in obesity and the great increase in mental
disorders,” Crews said in a telephone interview. “It’s as if
the exposure three generations before has reprogrammed the brain
so it responds in a different way to a life challenge.”

In the study, a group of rats were exposed once to
vinclozolin, a common fungicide used to protect fruits and
vegetables. This single contact altered how their genes were
activated, and future generations also carried this change,
though they never had been exposed to the chemical, Crews said.

Stress Reactions

When these descendants were then restrained as adolescents,
causing stress, their reactions differed from relatives of
unexposed rats. The affected rats also showed less interest in
new companions and spent more time in the corners of an open
field rather than the middle than rats whose ancestors weren’t
exposed. Rats related to the exposed animals that weren’t
stressed were obese, Crews said.

Crews tested the reactions of rats three generations after
exposure because humans are that far removed from the debut of
new chemicals seven decades ago, he said. During the 1940s,
powerful agricultural chemicals including DDT, the first
synthetic pesticide, and new types of plastics were introduced.

“The chemical revolution started in the 1940s, with World
War II and the development of organic chemistry, plastics,
detergents, fertilizers,” Crews said.

Andrew Feinberg, director of Johns Hopkins University’s
Epigenetics Center in Baltimore, said Crew’s theory may be
premature, after reading the paper.

Evidence ‘Not Clear’

“We should be very careful about overstating what looks
like basic science with public health implications,” Feinberg
said in an interview. “Currently we don’t have enough evidence
showing that these fungicides are causing common human disease
through an epigenetic mechanism. It’s research that’s well worth
doing, but it’s clear that that hasn’t been shown.”

Other studies in epigenetics, a field that investigates the
inheritance of cellular changes outside the realm of DNA, have
shown chemical exposure can affect fertility. A project by
researchers at Washington State University published in PLoS One
in February found that when pregnant rats are injected with
common environmental toxins, such as chemicals used in insect
repellents, plastics and jet fuel, offspring for three
generations have reproductive problems.

Japanese scientists are studying whether descendants of
atomic bomb survivors have inherited epigenetic changes that
make them more susceptible to cancer and heart disease.

“Diseases like autism, schizophrenia, bipolar disorder are
not single gene, or even a few genes, they’re complex of
genes,” Crews said. “It also turns out a lot of these genes
that we have identified are epigenetically modified.”

To contact the reporter on this story:
Ryan Flinn in San Francisco at
rflinn@bloomberg.net

To contact the editor responsible for this story:
Reg Gale at
rgale5@bloomberg.net

Please enable JavaScript to view the comments powered by Disqus.

Open bundled references in tabs:

Leave a Reply