Washington: Scientists are inching closer to developing a new blood test to detect early emphysema in smokers, a possible breakthrough which they say could help prevent thousands of deaths from the common lung diseases every year.
Emphysema is a type of chronic obstructive pulmonary disease (COPD) that damages to the air sacs in the lungs, causing trouble in breathing. It occurs mostly because of smoking.
Researchers at the NewYork-Presbyterian Hospital/Weill Cornell Medical Centre said the blood test they are developing can help warn smokers about impending development of the untreatable disease -- which is currently a major cause of disability and death in the US.
Not all smokers develop emphysema, but those who find out they are at risk will be motivated to quit to halt progression of the disease, said Dr Ronald Crystal, who led the study, published in the American Journal of Respiratory and Critical Care Medicine.
"We know, from other studies, that smokers who learn from objective evidence that their health is in danger are much more likely to quit. That is the only thing that will help them avoid this deadly disorder," he said.
The new test measures particles that are shed by tiny blood vessels known as capillaries that surround air sacs (alveoli) in lungs.
These particles are debris shed by ongoing injury to the air sacs -- damage that eventually results in devastation of the sacs and the "Swiss cheese" appearance of the lungs.
As the sacs are destroyed, people develop shortness of breath as they cannot take in enough oxygen to feed the body and eventually cannot remove carbon dioxide from the blood.
Dr Crystal and his team reasoned that as capillaries surrounding the air sacs are being injured, the debris would be carried out by the blood supply and could potentially be quantified as a disease biomarker. So they began to look for evidence of what they called endothelial microparticles (EMP).
To examine their theory, the researchers enrolled three groups of people -- healthy nonsmokers, healthy smokers, and smokers with early evidence of lung destruction.
The participants had their medical histories taken, and to gauge lung function in these participants, all underwent two pulmonary function tests and a test for their EMP levels.
The researchers found a 95 per cent positive correlation between elevated EMPs in the blood and an abnormal result from pulmonary function test, meaning that it detected nearly all verified cases of early emphysema in participants.