SHIRLEY S. WANG shared this article in the Wall Street Journal Newspaper on Sept. 22, 2014. I found it very informative.Doctors increasingly are recognizing that as many as half of asthma sufferers have a form of the lung disease known as nonallergic asthma. Some medications that help control symptoms of the more familiar allergic asthma aren’t as effective in nonallergic patients.
There is still much that isn’t understood about allergic asthma, which is brought on by an overactive response of the body’s immune system to food, pollen and other allergens. Even more mysterious is the cause of nonallergic asthma, which doesn’t involve an immune-system response. Symptoms for both forms of the disease typically include constricted airways, wheezing and coughing.
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Researchers also continue to discover substances in the environment that appear to increase the risk for developing asthma. One of the latest studies, from New York’s Columbia University Medical Center, found an association between asthma rates and phthalates, chemicals used in many plastic products that have raised health concerns.
The scientific hunt for the causes of asthma reflects concern about the puzzling rise in rates of the disease. In the U.S., the percentage of the population diagnosed increased in 2010 to 8.4%—or more than 25 million adults and children—from 5.5% in 1996, according to the most recent data from the Centers for Disease Control and Prevention. Some 1.8 million people visited a hospital emergency department in 2010 for asthma-related treatment.
Scientists studying nonallergic asthma say greater understanding of the molecular pathways in this form of the disease could lead to new targets for drug development.
Stefan Worgall, chief of the pediatric pulmonology, allergy and immunology division at Weill Cornell Medical College, and his colleagues recently discovered that when a normally occurring type of fat, known as sphingolipids, isn’t embedded properly in the cell walls in the lungs of mice, the airways constrict.
In a related experiment, they administered a drug to inhibit sphingolipid production in tissue taken from a healthy human lung. The tissue showed the same type of constriction as seen in the mice, the study found. The report was published last year in the journal Science Translational Medicine.
Dr. Worgall says the finding could help explain why obesity is a risk factor for asthma. Obese people tend to exhibit abnormalities in sphingolipids, he says.
Currently, Dr. Worgall and his team are measuring sphingolipid levels in the blood and breath of asthmatic children. Early findings suggest the levels appear abnormal, he says.
Jeroen Douwes, director of the Centre for Public Health Research, at Massey University in New Zealand, believes nonallergic-asthma patients might have particularly sensitive nerves in the lungs that tell the brain at a lower-than-normal threshold that a noxious substance is in the air and airways need to be constricted.
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