Chronic obstructive pulmonary disease (COPD) may be partly driven by the action of immune cells circulating in the blood that enters the tissues of the lungs, according to a recent study published in the online journal, PLoS ONE. This discovery from researchers at University of California Davis helps explain how smoking can cause the chronic lung condition.
“Understanding how a disease begins is an important step to develop new therapies, and knowing the mechanism and location of white blood cell recruitment to the lung early on in the development of COPD in this model will allow us to more rapidly screen drugs and determine how they work,” said Benjamin Davis, a researcher with the Center for Health and the Environment and the lead study author, in a recent statement from ScienceDaily.
Davis and fellow researchers used an animal model to study the effects of cigarette smoking on COPD development. Findings show that approximately 10 years of one-pack-a-day smoking led to prominent immune response in the lungs, including physical damage and scarring to the bronchial airways and accelerated inflammation and cellular changes that in turn can obstruct airflow and reduce normal lung function.
Further, this research demonstrates that tobacco-smoke exposure stimulates a specific type of white blood cell called a neutrophil to migrate out of bronchial blood vessels and accumulate in the lung tissues. While neutrophils can aid in tissue repair, researchers note that when present in excess and activated, these white blood cells can release enzymes that kill cells and accelerate inflammation.
The study also demonstrates that the immune cell-triggered inflammation begins in the blood that feeds the bronchial airways, rather than in the alveoli where oxygen is transferred to blood vessels.
“Tobacco-smoke-induced lung inflammation is the cause of most COPD cases,” wrote study authors. “These findings have important implications for understanding the etiology of COPD and suggest that pharmaceuticals designed to reduce leukocyte recruitment through the bronchial circulation may have promise as potential therapy to treat COPD.”
With this information, researchers now plan to test a variety of potential drugs that target these cells with the long-term aim of finding new ways to treat people with COPD.