In an accompanying editorial, Columbia University surgeon M. David Tilson, M.D., notes that the studies bring research on AAA formation and the role of the neutrophil to a new level and may lead to further discoveries that help sort out the AAA puzzle.
AAAs are an under-appreciated and under-researched public health threat, says Upchurch, who operates on dozens of AAA patients each year, including some whose aneurysms have already burst and who will die within minutes or hours if the bleeding isn't stopped. AAAs can go undetected for years; experts sometimes refer to them as a "ticking time bomb" inside a patient's abdomen.
In fact, an estimated 10 percent of all men over the age of 70 may have intact aortic aneurysms, which cause few symptoms except for occasional back pain or abdominal discomfort. If they are detected during this stage, for instance on a routine physical exam, X-Ray, MRI or CT scan, they can be repaired successfully 95 percent of the time.
Recently, new ideas about why aneurysms form have begun to take shape. "We're finding that in general, an aneurysm is an inadequate response to injury," Upchurch explains. "Something happens to damage elastin fibers in the blood vessel wall and, for some reason, the immune system's normal healing response doesn't work. Something eats away at smooth muscle cells in the wall of the aorta until it starts to fall apart."
Researchers have found that AAAs appear to be associated with high levels of enzymes that are capable of doing that eating. But the question of how those enzymes get there, and what prompts them to arrive, has been unanswered.
"Neutrophils are known to ca
Source:University of Michigan Health System