Carolina researchers develop new way to measure lung health

Blood sampling is a quick and accurate tool used to diagnose health conditions, like heart disease, diabetes and liver function. Researchers at the UNC School of Medicine and Marsico Lung Institute/Cystic Fibrosis and Pulmonary Research Center have developed a tool that can similarly monitors chronic lung conditions.

This new metric, called the Quantitative Mucin Index of the Lung, is described in a new study  published in the New England Journal of Medicine Evidence, written by 18 authors led by Mehmet Kesimer, a professor of pathology and lab medicine at the UNC School of Medicine. Significant study contributors from Marsico were Giorgio Radicioni, Agathe Ceppe, Amina A. Ford, Neil Alexis and Richard C. Boucher. The National Heart, Lung and Blood Institute — part of the National Institutes of Health — funded this work.

Called MUCQ, this tool analyzes sputum and other lung mucus samples to detect airway mucus abnormalities, assess disease risk and track disease progression in patients over time.

“MUCQ allows us to detect underlying mucus abnormalities before significant lung damage appears on standard lung function tests,” said Kesimer. “With an objective, biology-based measurement, we can now issue far more compelling evidence that will help physicians provide diagnoses and treatments sooner, rather than later.”

The role of mucins in lung health

Mucins are large proteins that make mucus slimy and thick. They play a crucial role, as the stickiness is what protects the respiratory system from pathogens, toxins and physical damage. While mucins serve a protective function, excess and/or increased concentrations of mucins can restrict and block the airways.

This risk is heightened in individuals exposed to cigarette smoke and environmental allergens, which can trigger mucin/mucus overproduction and lead to chronic bronchitis, chronic obstructive pulmonary disease or asthma. Early detection is key before progressive, widespread airway obstruction develops.

However, the diagnosis of chronic bronchitis, a common precursor for COPD, currently relies on patient questionnaires that subjectively assess cough and phlegm history. Until now, physicians and researchers had no real, objective way to gauge a patient’s risk of developing these kinds of lung diseases.

Quantitative mucin index of the lung

Kesimer and co-authors from the nationwide SubPopulations and InteRmediate Outcome Measures in COPD Study suggested that measuring two key airway mucins along with total mucin levels, may help identify risks associated with disease and determine disease progression.

SPIROMICS researchers then put their new score to the test. Using patient-derived samples from the study, they found that higher MUCQ scores sensitively and reliably indicated lung abnormalities. They were also linked to worse lung function, small airway disease, chronic bronchitis symptoms and greater risk of future COPD flare-ups.

Importantly, elevated MUCQ values were also observed in symptomatic smokers with normal lung function, which suggests that MUCQ could be an accurate way to detect airway disease earlier than standard lung function tests.

Kesimer adds that the use of MUCQ scores in clinical care may enable doctors to detect and track people who are at risk, giving them a chance to change their habits and lower their exposure before the disease develops or worsens.

“In the clinic, doctors always tell patients to stop smoking, but behavior change is hard,” said Kesimer. “Being able to show a patient an objective numeric value — like their MUCQ score — especially when their lung function still appears normal, can be far more convincing.”

“With MUCQ, we can identify and monitor at-risk populations, pushing them towards behavioral adaptations that would allow them to enjoy a higher quality of life and reduce the economic burden on the healthcare system.”