They found that chronic inhalation of polluted air in mice appears to activate a protein that triggers the release of white blood cells, setting off events that lead to widespread inflammation.
This finding narrows the gap in researchers’ understanding of how prolonged exposure to pollution can increase the risk for cardiovascular problems and other diseases.
The cellular activity they observed resembles an immune response that has spiraled out of control. A normal immune response to a pathogen or other foreign body requires some inflammation, but when inflammation is excessive and has no protective or healing role, the condition can lead to an increased risk for cardiovascular diseases, diabetes and obesity, as well as other disorders.
|AirMedic for particle and chemical control|
Though many questions about the beginning of this process remain unanswered, the scientists predict that the damage may originate in fluid that lines the lung. Tiny molecules in this fluid change structure after being exposed to polluted air, and that change appears to set off this cascade of damaging white blood cell behavior by activating a receptor called “toll-like receptor 4.”
“Our main hypothesis is that particulate matter stimulates inflammation in the lung, and products of that inflammation spill over into the body’s circulation, traveling to fat tissue to promote inflammation and causing vascular dysfunction,” said Sanjay Rajagopalan, professor of cardiovascular medicine at Ohio State and senior author of the study. “We haven’t identified the entire mechanism, but we have evidence now that activation of TLR4 influences this response.”
The research is published in a recent issue of the journal Circulation Research.
Editor’s note: This story was adapted from PR materials produced by Emily Caldwell and Ohio State University