Research Pinpoints Role of Biomarker in COPD

New findings suggest that patients with chronic obstructive pulmonary disease (COPD) and asthma have a protein in their lungs that leaks a small molecule into their bloodstream that restricts their breathing instead of relaxing their airways.

Published in the American Journal of Respiratory Cell and Molecular Biology, the report said the discovery could help clinicians diagnose and determine the severity of chronic lung diseases and make current treatments more effective.

The study discovered that a protein in the cell membranes of smooth muscles in the lungs of patients with chronic airway disease can leak cyclic adenosine monophosphate (cAMP), which transmits biological information to help relax muscles in the lungs and widen the airways. The leakage causes the airways to become constricted and cAMP can be found in the bloodstream, which can improve diagnosis of chronic airway diseases.

“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 coauthor Reynold A. Panettieri, Jr, MD, who is vice chancellor of translational medicine at Rutgers University, where researchers worked with scientists from the Yale School of Medicine on the finding about the leak of cAMP from human airway smooth muscle cells from patients with and without asthma.

“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.”

These cells control constriction of the airways in asthma and by losing cAMP the cells are more apt to constrict and worsen asthma. They next defined cAMP in the bloodstream as a biomarker by analyzing blood samples from a well-defined cohort of asthma patients.

“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.”

In the United States, 25 million people suffer with asthma and another 14 million with COPD.

Reference

Cao G, Lam H, Jude JA, et al. Inhibition of ABCC1 decreases cAMP egress and promotes human airway smooth muscle cell relaxation. Am J Respir Cell Mol Biol. Published online October 14, 2021. doi: 10.1165/rcmb.2021-0345OC