Smoke of Chimneys

Air Pollution Can Trigger Asthma Through Genetic Changes

Research presented yesterday at the American Academy of Allergy, Asthma, and Immunology (AAAAI) further explains how air pollution can cause new cases of asthma by triggering genetic and immune system changes. The senior investigator, Kari Nadeau, said,  “We’ve shown that the gene being changed is directly associated with asthma and severity of the asthma.”  Nadeau studied children in the highly polluted city of Fresno, California, and showed that exposure to polycyclyic aromatic hydrocarbon (PAH) caused genetic changes that in turn caused changes in immune function.

PAH is a type of chemical found naturally in the environment although they can also be man-made. They are created when substances such as coal, oil, and gas are burned, but not completely. A person can be exposed to PAH in a variety of ways, including vehicle exhaust fumes, wildfires, wood-burning stoves, fossil fuel combustion, barbecued meats, and cigarette smoke.

“What we have the most unique data on is to be able to trace a molecular level change at the DNA level to a cell function change, which was then associated with a health outcome such as asthma,” she said. “Unfortunately, this gene was changed over time and it was sustained. It doesn’t seem to be reversible.”

Pollution can trigger episodes  of asthma in people who already have the disease and that’s been well understood for some time. But the observation that pollution can trigger new cases through genetic changes in immune function is altogether new evidence of long-lasting damage from air pollution.

“We found that pollution modified the DNA in regulatory T cells that are sensitive to pollution. These regulatory T cells have a gene called FOXP3 and this gene was what we found to be most affected,” said Arunima Kohli, another investigator. Methylation of this gene increased in subjects exposed to higher PAH levels.

Click here to read more in Medscape, here to read the abstract presented at AAAAI and here to read related research in PLOS ONE.

Smoke of Chimneys is the Breath of Soviet Russia, poster from Wikimedia