From the article:
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 [abdominal aortic aneurysms] formation, MMP-9 is a cell-digesting enzyme that eats away at the wall of the aorta, leaving it vulnerable to expansion and rupture.
However, when Woodrum treated male rats with estradiol, a form of the female hormone estrogen, and then tested their aortas, he found that MMP-9 activity was substantially decreased. At this year’s meeting, Woodrum will receive an American College of Surgeons “Excellence in Research Award” for his study.
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“Earlier studies have demonstrated that increased estrogen systemically inhibits the development of AAAs,” Upchurch says. “Dr. Woodrum’s study extends earlier research and suggests that there also is something inherent in males that increases MMP-9 and may lead to greater AAA formation.”
“Estrogen affects production of MMP-9 by white blood cells called macrophages,” Upchurch adds. “MMPs degrade collagen and elastin, two major proteins in the aortic wall.