Okay, so you smoke cigarettes in a regular basis with no plans to quit. Lung cancer and respiratory ailments could be looming, but how do you know? A new blood test is being developed that detects the early development of emphysema well before symptoms occur and provide some form of peace of mind. Not all smokers develop emphysema, but finding out far in advance may just be the wakeup call you need.
Dr. Ronald G. Crystal, chairman and professor of genetic medicine and the Bruce Webster Professor of Internal Medicine at Weill Cornell Medical College and chief of the Division of Pulmonary and Critical Care Medicine at New York-Presbyterian Hospital/Weill Cornell Medical Center says:
“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.”
Emphysema and chronic bronchitis are the twin disorders that make up chronic obstructive pulmonary disease (COPD), which is now the fourth leading cause of death in Americans. Given the aging population, COPD is soon expected to move up to third in mortality prevalence.
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. The alveoli are where critical gas exchanges occur: blood in the capillaries brings carbon dioxide from the rest of the body for release into the air sacs, and the oxygen in the sacs (taken in from breathing) is taken up by the blood and transported to the rest of the body.
As the sacs are destroyed, people develop shortness of breath because they cannot take in enough oxygen to feed the body and eventually cannot remove carbon dioxide from the blood.
Dr. Crystal and his colleagues 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 micro particles (EMP).
Endothelial micro particles are small vesicles that are released from endothelial cells and can be found circulating in the blood. The micro particle consists of a plasma membrane surrounding a small amount of cytosol. The membrane of the endothelial micro particle contains receptors and other cell surface molecules which enable the identification of the endothelial origin of the micro particle, and allow it to be distinguished from micro particles from other cells, such as platelets.
Although circulating endothelial micro particles can be found in the blood of normal individuals, increased numbers of circulating endothelial micro particles have been identified in individuals with certain diseases, especially hypertension and cardiovascular disorders. The endothelial micro particles in some of these disease states have been shown to have arrays of cell surface molecules reflecting a state of endothelial dysfunction. Therefore, endothelial micro particles may be useful as an indicator or index of the functional state of the endothelium in disease, and may potentially play key roles in the pathogenesis of certain diseases, including rheumatoid arthritis.
The researchers found a 95% positive correlation between elevated EMPs in the blood and an abnormal DLCO test result, meaning that it detected nearly all verified cases of early emphysema in participants.
“Our blood vessels are always being replenished, so we all have some level of EMPs in our blood. What we are looking for are elevated levels of EMPs. For smokers, this is the equivalent of a smoke detector sounding its alarm; elevated levels of EMPs suggest their air sacs are being injured and it is time to act. We need a blood test that can be administered to the 20% of American adults who smoke as well as nonsmokers exposed to secondhand smoke — all who may not understand their risk of developing this progressive lung disease.”
Source: The American Journal Respiratory and Critical Care Medicine
Written by Sy Kraft, B.A.