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Linked to Generations of Disease
The research, led by Washington State University professor Michael Skinner, Ph.D., raises new concerns about exposure to endocrine disrupting pesticides and other toxics. While endocrine disruption during fetal development had already been linked to the adult onset of disease, the lab’s findings suggest such exposure could be leaving a legacy.
In one of two new studies published in Endocrinology, pregnant rats were exposed to vinclozolin, a fungicide commonly used in vineyards, during a window in fetal development that is sensitive to genetic reprogramming. The subsequent offspring and three additional generations were then monitored for health effects. Compared to controls, the exposed animals, male and female, had higher incidence of health problems and many had multiple afflictions. The incidence of some effects, such as kidney disease and immune problems, actually increased in the later generations.
"When we got them to age, we basically saw everything from breast tumors, prostate disease, kidney disease, immune dysfunction. We saw pretty much many of the major diseases we see in the human population," Dr. Skinner said.
The second study explains the mechanism for the transfer of disease. The groundbreaking work at Dr. Skinner’s lab has found disease can be passed down without a change in DNA sequence (i.e. mutation), but rather through epigenetic inheritance. Looking at the first three generations from the first study, the team was able to identify a series of genes that have undergone a change in the molecules attached to DNA. These molecules affect the behavior of a gene by controlling whether it is turned on or off.
These findings build on the team’s previous discovery that long-term reproductive effects can also be caused by epigenetic inheritance. Their previous work involved observing multigenerational effects on rats exposed to two pesticides, vinclozolin and methoxychlor, a multi-use insecticide. The first generation of offspring suffered reduced sperm counts and sperm motility. When the effected offspring reproduced with healthy females, more than 90 per cent of the subsequent generation displayed the same reproductive effects. The study was able to trace this effect over four generations.
To put the findings into perspective, Dr. Skinner said, "A human analogy would be if your grandmother was exposed to an environmental toxicant during mid-gestation, you may develop a disease state even though you never had direct exposure, and you may pass it on to your great-grandchildren."
“These discoveries illustrate not only the need for EPA to get back on track with implementing endocrine disruption assays, but also exactly why the precautionary principle is so important – we’re still discovering new ways these toxics affect our systems,” notes Laura Hepting, Special Projects Coordinator of Beyond Pesticides.