White blood cells, sent out by the body's immune system, causes inflammation in the lungs and ultimately leads to COPD. Smoking is the primary cause of COPD and researchers discovered that cigarette smoke causes a specific type of white blood cell to travel into the bronchial tissue of the lungs causing permanent scarring and damage. Identifying the beginning of COPD can lead to new treatments that can target COPD earlier and more effectively.
"If you smoke, ask your doctor about free intervention programs."
The study was led by Dr. Benjamin Davis, a researcher with the Center for Health and the Environment. Dr. Davis developed an animal model of COPD with an equivalent damage of 10 years of smoking a pack of cigarettes a day. Researchers wanted to find out how COPD began as well as how the body's immune system responded to cigarette smoke which would eventually lead to COPD. Researchers can use this model to see how drugs can treat early COPD.
Cigarette smoking causes the immune system to release neutrophils, a type of white blood cells, that then travel into the bronchial tissue of the lungs. The bronchial airways let air flow in and out of the lungs. The amount of neutrophils in the lung tissue causes inflammation. This inflammation can lead to scarring and lung damage ultimately obstructive airflow.
According to the study, COPD in its most severe form destroys the tissue lining the lungs. This causes the lungs to be more susceptible to infections and other diseases. This level of COPD is usually found in smokers who have been smoking for 30 to 40 years.
Neutrophils leave the bloodstream and enter into the tissue because cigarette smoke creates proteins call cell adhesion molecules that cause other cells to stick together. Neutrophils help to repair tissue but an excess number can lead to inflammation and damage.
Researchers also developed a new rat model to test and analyze COPD. The rats, when exposed to a certain level of smoke, have similar symptoms to 10-to-20 year smokers and 30-to-40 year smokers who have developed COPD. New treatments can be tested using this new model in the future.
Understanding how smoking causes COPD is important because nearly 80 percent of all COPD cases are because of smoking. Cigarette smoke, and all of the compounds that make up the smoke, destroys the epithelial tissue which manages airflow in the lungs. Getting to the root of COPD will allow for new drugs to be developed that target the particular mechanism that allows COPD to develop.
The study was funded by grants from the National Center for Research Resources of the National Institutes of Health and the Tobacco-Related Disease Research Program.
This study was published in the March edition of Public Library of Science.