Autism and Air Pollution
Breathing the particulates in polluted air can cause DNA defects and slow down cellular methylation processes, besides such well known consequences as lung and heart disease.
https://www.worldhealth.net/news/brea..._rapidly_chan/
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Breathing in pollutants can rapidly change DNA composition
Tiny bits of dust, metal and soot suspended in air can lodge deep in the lungs. Exposure to such particulate matter has been linked to respiratory diseases, lung cancer and heart problems.
While scientists may not understand exactly how inhaling the matter can cause health problems, a new study has shown that polluted air can also damage DNA. Moreover, according to researchers from the University of Milan, breathing in particulate matter can reprogram genes in as little as three days. And DNA damage can result in increased rates of cancer and other diseases.
In the study, led by Andrea Baccarelli, blood samples of 63 steel-foundry workers in Brescia, Italy, were taken on the first day of the work week, before they had been exposed to the foundry's air, then again a few days later. As they discovered, the DNA of the exposed workers had been damaged by a slowed rate of "methylation," a biological process in which genes are organized into different chemical groups.
With fewer groups, fewer genes were made into proteins, which, say the researchers, is critical to the body's regular maintenance system. "Comparisons between the two samples revealed significant changes in the methylation of four genes that may suppress tumors," says Baccarelli. Similar reduced-size gene groups have also been found in the blood DNA of lung cancer patients.
The University of Milan research team speculates that the same changes could occur in people who live in cities, although it would probably take weeks or even months for the effects to show up. And in fact, previous research conducted by Baccarelli has shown that elderly people living in Boston had DNA damage from breathing in particulate matter.
"Other investigators have shown that inhalation of particulate matter affects DNA through the methylation process," notes John Heffner, professor of medicine at Oregon Health and Science University and past president of the American Thoracic Society. "What these investigators have done is show that the genes affected are ones that are known to be related to the development of lung cancer."
Baccarelli emphasizes that the results need to be confirmed in air pollution studies before they can be extended to the general population. In the meantime, however, related work by his team raises the possibility that folic acid, which is naturally found in many foods, may be able to slow or even reverse methylation damage from particulate matter. "The vitamin may make methylation machineries more efficient," he says, and adds that "we found that subjects with higher intakes of methyl nutrients were protected from some of the cardiac effects of particulate matter."
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Now a latest study has linked air pollution to autism, which is well known as a disease with a large number of DNA defects and poor cellular methylation.
https://www.physorg.com/news/2010-12-...ay-autism.html
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Living near a freeway may be associated with increased risk of autism, according to a study published by a team of researchers from Children's Hospital Los Angeles, the Keck School of Medicine of the University of Southern California (USC) and the UC Davis MIND Institute.
"Children born to mothers living within 309 meters of a freeway appeared to be twice as likely to have autism," said Heather Volk, PhD, MPH, and first author on the study. Dr. Volk holds a joint appointment at the Community, Health Outcomes & Intervention Research Program at The Saban Research Institute of Children's Hospital Los Angeles, the Zilkha Neurogenetic Institute and the Department of Preventative Medicine at USC.
Autism is a developmental disorder that has long been ascribed to genetic factors. While changes in diagnostic criteria and increased awareness have been thought to contribute to the rising incidence of the disorder, these factors alone cannot explain the dramatic increase in the number of children affected. The Centers for Disease Control reported a 57 percent increase between 2002 and 2006. This study supports the theory that environmental factors, in conjunction with a strong genetic risk, may be one possible explanation for the increase.
While little is known about the role of environmental pollutants on autism, air pollution exposure during pregnancy has been seen to have physical and developmental effects on the fetus in other studies. Exposure to air pollution during the first months of life has also been linked to cognitive developmental delay. However, the authors said that this study is the first to link exposure to vehicular pollutants with autism risk, though direct measurements of pollutants were not made.
Data from children with autism and typically developing children, who served as controls, were drawn from the Childhood Autism Risks from Genetics and the Environment (CHARGE) study, a population-based case-control study of preschool children. Children were between the ages of 24 and 60 months at the start of the study and lived in communities around Los Angeles, San Francisco and Sacramento. Population-based controls were recruited from state of California birth files, and were frequency matched to the autism cases by age, gender, and broad geographic area. Each participating family was evaluated in person. All children were assessed; assessment of autism was done using well-validated instruments.
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