October 20, 2021
Rutgers University researchers have identified a potential biomarker for asthma and chronic obstructive pulmonary disease that may help doctors better diagnose the lung conditions.
At the heart of the discovery is a protein in the lungs that can leak a molecule called cyclic adenosine monophosphate, or cAMP, into the bloodstream, constricting the airways.
The molecule's job is to transmit biological information that helps relax lung muscles and widen the airways. But when cAMP is lost due to a leakage into the bloodstream, the opposite occurs.
The researchers said their findings may help doctors better determine the severity of chronic lung disease and lead to more effective bronchodilators – medications that relax the muscles that tighten the airways.
"This protein has been recognized as important in some diseases, but it has never been defined before in airway diseases, such as asthma and COPD, until now," said Dr. Reynold Panettieri, vice chancellor of translational medicine at Rutgers.
"In addition to identifying this protein, we demonstrated that if you decrease the leakage, the smooth muscles in the airways relax, which could be potentially very important in improving asthma and COPD management. In addition, the presence of too much cAMP in a patient's blood is a new biomarker that can help characterize specific types of asthma and COPD."
About 25 million U.S. residents have asthma and another 14 million have chronic obstructive pulmonary disease.
An asthma diagnosis requires a physical exam that may include a lung function test and an X-ray of the lungs or sinuses. A COPD diagnose may require a lung function test, a chest X-ray, a CT scan to detect emphysema and a blood test to measure how well the lungs oxygenate the blood and remove carbon dioxide.
For the study, Rutgers researchers collaborated with the Yale School of Medicine to analyze cAMP leakage in patients with and without asthma. They also analyzed blood samples from a group of asthma patients.
Losing cAMP molecules causes smooth muscle cells to constrict, worsening the asthma, the researchers found. And because the molecules are leaking into the bloodstream, they easily can be identified as a biomarker of asthma or chronic obstructive pulmonary disease.
"We determined that cAMP blood levels are higher in asthma patients," Panettieri said. "This knowledge allows for better diagnostics of the illness and forms the basis for new therapeutics that will plug the leak of cAMP in the protein."
The study was published in the American Journal of Respiratory Cell and Molecular Biology.
Asthma is a chronic condition that affects the lungs and requires ongoing management. An asthma attack occurs when the lungs become inflamed, constricting the airway.
Asthma symptoms – difficulty breathing, wheezing, coughing and tightness in the chest – are triggered by allergens or irritants that enter the lungs. But not everyone with asthma has allergies. Other asthma triggers include tobacco smoke, dust mites, cockroach droppings, air pollution, strong odors, fumes and intense exercise.
Chronic obstructive pulmonary disease causes breathing difficulties, coughing and wheezing that worsens over time. Occupational and environmental exposures are known risk factors.