Autism is something we are, as a society, getting more and more familiar with. A new study shows that at least 1 in 45 children in the US are now diagnosed with autism. It is no secret that fungicides (among other chemicals) are used daily in farming to keep the year’s crop from being eradicated. It is also no secret that a lot of the chemicals in pesticides are harmful to human and animal health. The fine line of just how much damage to the eventual consumer of these farmed foods has to be drawn and redrawn on an almost daily basis, and re-evaluations have to be constant in order to keep the consumer safe. Dr. Mark Zylka out of the University of North Carolina School of Medicine has studied a class of commonly used fungicides and a found that they produce gene expression changes similar to the changes in people with autism and neurodegenerative diseases like Alzheimer’s and Huntington’s.
The study exposed mouse neurons to about 300 different chemicals. The RNA (ribonucleic acid, the single stranded counterpart of DNA that is charged with coding, decoding, regulation and expression of genes) is then sequenced to find out which genes would be misregulated compared to mice that were untreated. Six chemical groups were described depending on how they altered gene expression. One of these groups altered many of the genes involved in brains of people with autism and alzheimer’s disease. The pesticides in this group were rotenone, pyridaben and fenpyroximate. Also included are fungicides like pyraclostrobin, trifloxystrobin, fenamidone, and famoxadone. The study doesn’t pinpoint the blame on these chemicals as further study is needed to figure out the real epidemiology (how the chemicals affect health and control of disease). Zylka and his group also figured out that the chemicals reduced the expression of genes involved in synaptic transmission (the connections important for communication between neurons). This would result in lower brain function. The chemicals also caused an elevated expression of genes that express inflammation in the nervous system. This kind of neuroinflammation is commonly seen in autism and neurodegenerative diseases.
Zylka’s group also checked the use of these chemicals via the U.S. Geological Survey and found out that as there are some chemicals that have declined in use, most others are the same and some like the fungicides have increased use over the past decade. Further study as to how each chemical affects the end consumer, and how much exposure is needed to have a cumulative effect on the brain. Zylka hopes that this study will be a wake-up call for regulatory agencies and the scientific and medical communities to look into this on a deeper level.Source: Nature Communications