When it comes to abdominal aortic aneurysms – life-threatening bulges or weak areas in the main artery feeding blood to the lower half of the body – new U-M research shows that it is definitely better to be female. During 2000, about 11,000 people in the United States died from a ruptured abdominal aortic aneurysm. Eighty percent of these aneurysms, which doctors call AAAs for short, occur in men. Scientists know very little about why this often-undetected condition, for which there is no medical treatment, strikes men more often than women. But vascular surgeons at the University of Michigan Medical School have found some intriguing clues.At this week’s American College of Surgeons meeting in New Orleans, Derek T. Woodrum, M.D., a U-M resident in general surgery, will present new research results showing that smooth muscle cells from aortas of male rats contain 2.5 times more destructive MMP-9 protein and 10 times the level of MMP-9 gene expression compared to the same cells from female rat aortas. Known to be involved in AAA formation, MMP-9 is a cell-digesting enzyme that eats away at the wall of the aorta, leaving it vulnerable to expansion and rupture.
