Cat Allergen Wreaks Havoc on Asthmatic Lungs
Reported November 30, 2005

 
(Ivanhoe Newswire) -- Researchers have discovered cat allergens can weaken lungs of people with asthma for more than 22 hours after contact.

Nearly 15 million Americans have asthma. Cat allergen exposure can greatly add to their morbidity rate. Those affected by the allergens can experience inflammation in the small airways for more than 22 hours but may not have any symptoms. This inflammation often leads to severe asthma attacks.

Jared W. Allen, Ph.D., researcher at David Geffen School of Medicine at the University of California, Los Angeles, says, "[We] studied cat allergen because it's an extra-fine particle that is both airborne and capable of penetrating deep into the small airways of the lungs."

With conventional pulmonary function tests, the prolonged inflamed lung is hard to detect. Dr. Allen and colleagues, however, have developed a high-resolution computed tomography method that examines the small airways deep in the lungs and reveals the extent of damage.

For the study, researchers evaluated 10 patients with asthma for three days after exposure to cat allergens. Researchers found all 10 patients had severe decrease in lung function long after their symptoms had subsided.

"Twenty-two hours after exposure, patients appeared to have otherwise recovered from respiratory symptoms according to clinical measures," Dr. Allen says. "However, HRCT still showed significant air trapping, suggesting that constriction and inflammation of the small airways remain long after initial exposure."

Dr. Allen hopes physicians will look closer at the issues surrounding small airways of asthmatic people. He says it is difficult to reach these regions of the lung with conventional inhalers and hopes the HRCT will help the development of inhaler devices and oral anti-inflammatory drugs capable of generating extra-fine particles to reach the small airways and suppress inflammation deep in the lung.

Dr. Allen says, "A better understanding of the causes and complications of asthma, as afforded by this type of imaging, will lead to improved and targeted therapies for this disease." Dr. Allen also believes, "The quantitative image analysis used in this study may be one of the safest ways to evaluate the efficacy of these new drugs and aerosols in the treatment of asthma."

SOURCE: Annual meeting of the Radiological Society of North America in Chicago, Nov. 26 - Dec. 2, 2005