Discovery of how pollution damages airways raises new hope

The Indian Express , Wednesday, January 19, 2011
Correspondent : Agencies

Scientists have discovered how nano particles from diesel exhaust damage airway cells of human lungs, a finding they claim could lead to new therapies for people susceptible to airway diseases.

The researchers from the Duke University Medical Center also found that the severity of the injury depends on the genetic make-up of the affected individual.

"We gained insight into why some people can remain relatively healthy in polluted areas and why others don't," said Wolfgang Liedtke, an assistant professor in the Duke Department of Medicine who led the study.

Diesel exhaust particles -- a major part of urban smog – consist of a carbon core coated with organic chemicals and metals.

The Duke team found that the particle core delivers these organic chemicals onto brush-like surfaces called cilia, which clear mucus from the airway lining.

Contact with these chemicals then triggers a "signalling cascade" as the cells respond, the researchers reported in the journal Environmental Health Perspectives.

In some patients, who have a single "letter" difference in their DNA, a circuit called the TRPV4 ion channel signals more strongly in response to the pollutants.

Previous research showed that this gene variant makes humans more liable to develop chronic-obstructive disease (COPD), and the current study provides an explanation for this observation.

About 75 per cent of people have the version of the gene MMP-1 that leads to greater production of the molecule MMP-1 mediator, which destroys lung tissue.

This genetic make-up allows for a turbo-charged production of MMP-1, which damages airways and lungs at multiple levels, Liedtke said.

A more fortunate 25 per cent of people, he added, escape this high level of production of MMP-1, which may be reflected in the fact that certain individuals can better manage the effects of air pollution without grave airway damage.

The injurious molecule MMP-1 is known to enhance the development of certain devastating lung diseases, such as chronic-obstructive pulmonary disease (COPD) -- a top-ten ailment causing morbidity and mortality, according to WHO.

According to Liedtke, the devastating tissue-destructive actions of MMP-1 can also lead to lung emphysema – the chronic reduction of the lung surface because of gaseous exchange and the spread of lung cancer cells.

The new study also provides a direction for developing therapeutics for those who are genetically more susceptible to air pollution and airway damage, Liedtke said.

"If we can find a way to stop the hyper-activation of MMP-1 in response to diesel-engine exhaust particles and reduce it to levels that the airways can manage, then we will be helping a large number of people worldwide," he said.

"It is attractive to envision inhaled TRPV4 inhibitor drugs, rather than swallowing a pill or taking an injection. I envision this as rather similar to inhaled drugs for allergic airway disease that are currently available."

 
SOURCE : http://www.indianexpress.com/news/discovery-of-how-pollution-damages-airways-raises-new-hope/739036/2
 


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