According to the Johns Hopkins Medical School study, a decrease in lung concentrations of NRF2-dependent antioxidants, key components of the lung's defense system against inflammatory injury, is linked to the severity of chronic obstructive pulmonary disease (COPD) in smokers.
Broccoli is known to contain a compound that prevents the degradation of NFRP.
The findings were published in the second issue for September of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
To reach the conclusion, the researchers examined tissue samples from the lungs of smokers with and without COPD to determine if there were differences in measured levels of NRF2 expression and the level of its biochemical regulators, including KEAP1, which inhibits NRF2, and DJ-1, which stabilizes it.
Dr. Shyam Biswal had previously shown that disruption in NRF2 expression in mice exposed to cigarette smoke caused early onset of severe emphysema.
When compared to non-COPD lungs, the lungs of patients with COPD showed markedly decreased levels of NRF2-dependent antioxidants, increased oxidative stress markers, a significant decrease in NRF2 protein with no change in NRF2 mRNA levels (indicating that it was expressed, but subsequently degraded), and similar KEAP1
evels, but a marked decrease in the level of DJ-1.
"NRF2-dependent antioxidants and DJ-1 expression was negatively associated with severity of COPD," wrote principle investigator, Shyam Biswal, Ph.D., an associate professor in the Bloomberg School's Department of Environmental Health Sciences and Division of Pulmonary and Critical Care at the Johns Hopkins School of Medicine.
Therapy directed toward enhancing NRF2-regulated antioxidants may be a novel strategy for attenuating the effects of oxidative stress in the pathogenesis of COPD," he added.