Researchers in Australia have demonstrated that blocking a certain protein can reduce or prevent cigarette smoke-induced lung inflammation in mice. Inflammation underlies the disease process of chronic obstructive pulmonary disease (COPD) and many other smoking-related ailments.
The findings have been published online ahead of print publication in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
Cigarette smoking causes lung inflammation, which can lead to oxidative stress, emphysema, small airway fibrosis, mucus hypersecretion and progressive airflow limitation. Since the inflammatory reaction to cigarette smoke responds poorly to current anti-inflammatory treatments, there is intense research to identify more effective therapies for cigarette smoke-induce lung damage.
Granulocyte macrophage-colony stimulating factor (GM-CSF) is of special interest because it governs the growth, activation and survival of leukocytes directly implicated in the pathogenesis of COPD.
Cigarette smoke triggers the release of GM-CSF and other cytokines and chemokines which cause activation and recruitment of more inflammatory cells into the lung,thereby perpetuating the inflammatory response and exacerbating ongoing inflammation. These activated and recruited inflammatory cells also release proteases such as matrix metalloproteinase (MMP)-12, which destroy the lung tissue, resulting in emphysema.
The research team from the University of Melbourne set out to determine whether blocking GM-CSF could reduce the inflammation and other deleterious effects of cigarette smoke exposure in mice.
To do so, they exposed a group of mice, half of which had been treated with a GM-CSF blocking agent, anti-GM-CSF, and half of which were controls, to the equivalent of nine cigarettes of smoke each day for four days. At the end of four days, the mice were killed and their lung tissue was examined for the presence of inflammatory cells.