By activating dozens of genes that combat free radicals and toxic pollutants in cigarette smoke, a naturally produced protein called Nrf2 can stand as a stalwart defender against emphysema, a new study suggests.
The finding indicates that variations in the gene encoding Nrf2 might partly explain why some smokers get emphysema while others don't. Cigarette smoking accounts for most cases of the lung ailment, which is the fourth leading cause of death in the United States.
Cigarette smoke contains highly reactive free radicals—unstable molecules that destructively oxidize other molecules, including DNA. Fortunately, vitamins C and E and other antioxidant compounds continually clear oxidizing radicals from the body.
Past research showed that Nrf2 activates genes that encode antioxidant proteins. But its full role has been unclear.
In the new study, researchers compared mice that lacked the Nrf2 gene with others that had such a gene. After exposin