Researchers have long known that mice could regenerate one lung when the other is missing. Now, a new study has helped to identify the biochemical trigger behind this process. The findings, researchers hope, could be used to treat millions with respiratory disorders.

In the study published in the journal Cell, mice that had their left lungs removed were able to regenerate their right lungs by 80 percent -- although the phenomenon occurred only after a trauma abruptly reduced lung mass.
Researchers found that after lung removal, endothelial cells lining blood vessels in the lung increased production of a specific protein (MMP14), which then appeared to activate new air sac (alveoli) growth in the lungs.

Researchers at Weill Cornell Medical College in New York believe the same process may take place in humans.

It is speculated, but not proven, that humans can regenerate air sacs in their lungs, says lead researcher Dr. Shahin Rafii.

"Our hope is to take these findings," Dr. Rafii said, "and see if we can induce lung regeneration in patients who need it, such as those with chronic obstructive pulmonary disease."