Scientists discover how airborne particles can exaggerate airway inflammation

An international team of scientists has observed a previously unclear inflammatory mechanism caused by airborne particles that can worsen the symptoms of asthma. Toxicological sciences.

As the world industrializes more and more, the risk of developing respiratory diseases increases. The very small particles released by the emanations of the industry and vehicles are harmful to health, but we still do not know how. In a collaborative study, researchers in Japan, the United States, and Germany have discovered a mechanism that can exaggerate inflammation in response to diesel fumes and worsen symptoms of respiratory illness.

Tiny particles in the air are released by diesel exhaust vehicles, factories or cityscapes. People living in urban or industrial areas have a higher risk of developing diseases such as asthma. However, the mechanism of development of asthma is very complicated, says badociate professor Yasuhiro Ishihara of the Graduate School of Integrated Science for Life of Hiroshima University. Many different factors can trigger asthma, such as genetics and allergies, but Ishihara speculates that:

If we know the mechanism, we may be able to prevent particle-induced asthma. "

Research teams from Hiroshima University, the University of California and the Leibniz Research Institute have identified a cell-activated receptor activated by these particles, called AhR. This receptor promotes the production of inflammatory molecules to eliminate toxins present in the body (such as vapors and diesel particles). It is found on the cells of organs in contact with the air, such as the skin, intestines and lungs. The function of the AhR is to detoxify the body, but excessive activation of this receptor can often cause health problems.

In their study, the group stimulated human and mouse immune cells with diesel particles that activated AhR. The cells produce IL-33, a chemical messenger that promotes inflammation. To confirm that IL-33 levels were caused by AhR, the researchers blocked AhR signals in the cells and no IL-33 was found.

The researchers concluded that activation of AhR by airborne particles can worsen symptoms of diseases such as asthma. Diesel fumes push immune cells to release chemicals that promote inflammation.

Ishihara says that while this discovery is promising and opens the door to a deeper understanding of the mechanisms of these diseases, the best way to avoid them is to "escape". Even if you do not live right next to a factory or many vehicles, airborne particles can be distributed by the wind.

"This is an urgent problem in our radically developed world." Ishihara emphasizes.

Although scientists are doing great research to improve our quality of life in the city, living in the countryside could still be the best way to avoid asthma due to particles.