Scientists from east China's Zhejiang University have for the first time identified the relationship between airway diseases and environmental particulate matter (PM).
Scientists discovered that autophagy, a normal physiological process in the body that destroys cells, leads to inflammation and mucus hyperproduction induced by particles 100 to 500 times thinner than a human hair.
Invading PMs that contain a large amount of inorganic carbon, heavy metal and other toxic substances are normally engulfed by cells in human airways and result in dark particles, which do not degrade, causing inflammation and chronic airway diseases if accumulated.
"Conversely, a genetic blockage of autophagy can markedly reduce PM-induced airway diseases," said Shen Huahao, a leading researcher.
Mice with impaired autophagy due to knockdown of a related gene displayed significantly reduced airway inflammation and mucus hyperproduction in response to PM exposure.
"If inhibition of autophagy is proven effective in human, treating PM-induced airway diseases will become easier and more targeted," said Chen Zhihua, first author of the paper that is published by Autophagy online journal early Wednesday.
Chen said the team is currently working on inhibitive medicine that will be tested on human.
PM is capable of inducing asthma, airway injuries and lung cancer in extreme cases, while the origin and development of the diseases remain largely unclear.
Smog and haze have a heavy concentration of hazardous fine and ultrafine PMs that stay longer and travel farther than normal particles. They are more easily inhaled by humans.
Heavy smog in eastern China Tuesday prompted local authorities to issue a yellow alert, the third highest in a four-tier warning system, and order schools to halt outdoor activities.
Beijing and cities in northeast China also experienced their worst ever smoggy days this month, forcing governments and residents to take protective measures.
The Chinese capital issued its first ever red alert, the highest, for air pollution on Dec. 7 after the worst period of air pollution this year took Air Quality Index readings to the maximum 500.
According to the research team, more than 1 billion people worldwide suffer PM-related chronic airway diseases.
