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Diesel exhaust can alter DNA: study

UBC researchers put volunteers into polycarbonate-enclosed booth containing exhaust fumes


Just two hours of exposure to diesel exhaust fumes can lead to fundamental health-related changes in biology, a new study from the University of British Columbia (UBC) and Vancouver Coastal Health has suggested.

The study, “Short-term diesel inhalation in a controlled human crossover study is associated with changes in DNA methylation of circulating mononuclear cells in asthmatics”, was published in January in the journal Particle and Fibre Toxicology. It found that diesel exhaust caused changes in methylation, the carbon-hydrogen “coating” that attaches to many parts of a person’s DNA, affecting about 400 genes at about 2,800 different points. In some places, it led to more methylation, but more often, it decreased methylation, the study said.

The study involved putting volunteers in a polycarbonate-enclosed booth — about the size of a standard bathroom — where they breathed in diluted and aged exhaust fumes “that are about equal to the air quality along a Beijing highway or under certain conditions at busy ports, rail yards, mines and industrial sites,” the UBC said in a statement. The researchers examined how diesel exhaust exposure affected methylation, which can silence or dampen a gene, preventing it from producing a protein — sometimes to a person’s benefit, sometimes not.

The statement said that the next step for researchers is to examine how these changes in gene expression translate to health. “Usually when we look at the effects of air pollution, we measure things that are clinically obvious — air flow, blood pressure, heart rhythm,” said Dr. Chris Carlsten, an associate professor in the UBC’s Division of Respiratory Medicine. “But asthma, higher blood pressure or arrhythmia might just be the gradual accumulation of epigenetic changes,” he added, referring to the field of gene expression. “So we’ve revealed a window into how these long-term problems arise.”

The fact that DNA methylation was affected after only two hours has positive implications, added Dr. Carlsten, who is also the AstraZeneca chair in occupational and environmental lung disease. “Any time you can show something happens that quickly, it means you can probably reverse it — either through a therapy, a change in environment, or even diet,” he said.

The study has implications for workers who are at risk of diesel exhaust exposure, such as toll booth operators, mechanics, loading/shipping dock workers, farmers, railroad workers and ship crew members. According to information from the Canadian Centre for Occupational Health and Safety, exposure to diesel exhaust can cause coughing and itchy/burning eyes, while breathing in exhaust can cause lung irritation and/or an allergic reaction, causing asthma or making pre-existing asthma worse. “Years of exposure to diesel exhaust may increase the risk of lung cancer and possibly bladder cancer,” the information added.

To read the study, visit http://www.particleandfibretoxicology.com/content/11/1/71.