Researchers have identified a molecule that plays a key role in causing the symptoms of asthma, a finding that could lead to new treatments for the breathing disorder that affects 15 million Americans.
Two teams of researchers experimenting independently with laboratory mice have found that a reaction triggered by a molecule called interleukin-13, or IL13, was a primary cause of the inflammation, clogging and restricted air flow that cause breathing problems in asthma attacks.
The two studies will appear Friday in the journal Science.
At Johns Hopkins University, researchers treated asthma-prone mice with a drug that blocks the action of IL13.
When the mice were exposed to an allergen, a substance that normally caused asthma attacks, the animals developed no breathing problems. Mice not treated with the IL13 blocker, however, had the inflammation and restricted airways typical of asthma.
In another study, researchers at the University of California, San Francisco, applied IL13 blocker to the nasal passages of mice and then exposed the animals to an asthma-causing protein.
Animals treated with the IL13 blocker had few asthma symptoms, the scientists report.
The University of California team also found that another molecule, interleukin-4, or IL4, also played a role in asthma. But, said David Corry of the university, "IL13 may be more potent."
If the mouse experiments can be duplicated in humans, they could give new targets for drugs that treat asthma at the cellular level. Such drugs, in effect, would stop an asthma reaction at its source instead of treating just the symptoms of the disorder.