Dr. Rafii and his researchers had previously uncovered growth factors that control regeneration in the liver and bone marrow, and in both cases, they found that endothelial cells produce the key inductive growth factors, which they defined as "angiocrine factors." In the current lung study, they discovered the same phenomenon -- that blood vessel cells in the lungs jump-start regeneration of alveoli. "Blood vessels are not just the inert plumbing that carries blood. They actively instruct organ regeneration," says Dr. Rafii. "This is a critical finding. Each organ uses different growth factors within its local vascular system to promote regeneration."
To conduct this study, Dr. Bi-Sen Ding, a postdoctoral fellow in Dr. Rafii's lab and the first author of this paper, removed the left lungs of mice and studied the biochemical process of subsequent regeneration of the remaining right lung. Previous pioneering work by Dr. Crystal had shown that when the left lung of mice is removed, the right lung regenerates by 80 percent, effectively replacing most of the lost alveoli. "This regeneration process also restores the physiological respiratory function of the lungs, which is mediated by amplification of various epithelial progenitor cells and regeneration of the alveolar sacs," says Dr. Ding.
"This regenerative phenomenon, however, only occurs after a trauma that abruptly reduces lung mass. Then the specific subsets of blood vessels in the remaining lung receive a message to start to repopulate alveoli, and our job was to find that signal," says Dr. Daniel Nolan, a senior scientist in this project who developed methods to characterize the lung
|Contact: John Rodgers|
New York- Presbyterian Hospital/Weill Cornell Medical Center/Weill Cornell Medical College