NEW YORK (Reuters Health) - People who suffer with the chronic breathing disorder known as COPD may benefit from a second helping of broccoli at dinner, research published today suggests.
COPD, which stands for "chronic obstructive pulmonary disease," is a progressive lung condition that is mostly seen in smokers and former smokers. It is characterized by emphysema and chronic bronchitis, which obstructs air flow to the lungs.
Dr. Shyam Biswal from The Johns Hopkins School of Medicine in Baltimore and colleagues have found a correlation between more severe COPD and a decrease in lung concentrations of a specific protein called NRF2, which defends the lung against inflammation-related injury. Broccoli contains a compound that helps stabilize NRF2 levels in the lung.
Biswal and colleagues analyzed tissue samples from the lungs of smokers and former smoker with or without COPD. When compared with healthy lung tissue, COPD lung tissue showed a marked decline in the activity and concentrations of NRF2-dependent, inflammation-fighting antioxidants.
This defect seen in the COPD lung appears to be associated with reduction in another protein called DJ-1, whose main function is to stabilize NRF2 and prevent its degradation.
Clear signs of cell-damaging oxidative stress in the COPD lungs were also evident.
In the lab, the broccoli compound sulforaphane was able to restore the antioxidant imbalance in COPD lung tissue, the researchers found.
These observations point to the potential of using drugs to boost NRF2-regulated antioxidant defenses in the lung in patients with COPD, Biswal and colleagues conclude in a report in the latest issue of the American Journal of Respiratory and Critical Care Medicine.
"Future studies should target NRF2 as a novel strategy to increase antioxidant protection in the lungs and test its ability to decrease exacerbations and improve lung function in patients with COPD," Biswal said.
Increasing NRF2 "may also restore important detoxifying enzymes to counteract other effects of tobacco smoke," Dr. Peter Barnes of the National Heart and Lung Institute in London, writes in a commentary published with the study. This was been achieved in animals by isothiocyanate compounds, such as sulforaphane, which occurs naturally in broccoli, he explains.
In a written statement, Dr. John Heffner, past president of the American Thoracic Society, commented that "mounting evidence over several decades underscores the importance of oxidant-mediated damage for the development of COPD in addition to other lung diseases."
"This study adds greater precision to our understanding of the specific antioxidants that may protect the lung against (COPD) to allow clinical trials based on valid pathophysiologic principles," Heffner added.
SOURCE: American Journal of Respiratory and Critical Care Medicine, September 2008.