Scientists at Case Western Reserve University have discovered that asthma may be driven by 'pseudo leukotrienes' formed through free-radical reactions, rather than the traditionally blamed leukotrienes produced by enzymes. These molecules appear at higher levels in asthma patients, correlating with symptom severity. The finding suggests potential new treatments targeting the root cause of inflammation.
For decades, asthma has been understood as an inflammatory condition primarily triggered by leukotrienes, chemicals released by white blood cells in response to irritants or allergens. These molecules narrow the airways, leading to breathing difficulties, and drugs like Singulair have been developed to block their effects by targeting the same receptor.
However, a new study from researchers at Case Western Reserve University challenges this view. Led by Robert Salomon, the Charles Frederic Mabery Professor of Research in Chemistry, the team identified 'pseudo leukotrienes'—molecules structurally similar to leukotrienes but formed differently. Unlike enzyme-driven leukotrienes, these arise from uncontrolled free-radical reactions that add oxygen to lipids, creating a rapid, explosive inflammatory process.
"The free radical process is almost like an explosion or a fire," Salomon explained. "It's just like when oxygen reacts with fuel and you get flames. It can easily get out of control."
Analysis of urine samples revealed that pseudo leukotriene levels were four to five times higher in people with asthma compared to those without, and they closely matched disease severity in mild and severe cases. The researchers suggest these could serve as biomarkers for monitoring asthma and treatment efficacy.
Current treatments block the receptor where both types of molecules bind, but Salomon argues for a more precise approach: "The real importance of this discovery is the possibility of treating these diseases with drugs that prevent the free radical process or moderate it rather than drugs that block the receptor."
The study, funded by the U.S. National Institutes of Health, appears as a pre-proof in the Journal of Allergy and Clinical Immunology. Collaborators included experts from Case Western Reserve, the University of Toledo, and Cleveland Clinic Children's Hospital. Future research will explore roles in other conditions like RSV, bronchiolitis, and COPD, with broader implications for neurological diseases such as Parkinson's and Alzheimer's.
