Related to endothelium
"We wanted to apply our knowledge of CO production in the tissues to traumatic injury," McCarty said. "We're looking at CO's function in the peripheral circulatory system, in particular, at the effect it has on the endothelium."
A serious laceration damages the vascular endothelium, comprised of cells lining the blood vessels, by pulling and tearing it. When the endothelium is torn, it disrupts the production of nitric oxide synthase (NOS), a blood vessel dilator that is even more powerful than CO. The loss of NOS production at the area of tissue damage helps control bleeding, because the vessels dilate less without it. However, CO continues to dilate the vessels around the wound, and that is why it is important to inhibit CO, the remaining vessel dilator.
"One of the great things about what we've found is that by blocking the effects of CO, only the area of endothelial damage constricts," McCarty said. "The undamaged vessels continue to get blood to the other areas of the body." This control of bleeding at the site of the trauma while allowing circulation in the rest of the body is one of the most exciting aspects of the study, she said.
Trauma to liver
In the study's first phase, the researchers removed tiny blood vessels, known as arterioles, from rats, and put the vessels in a chamber that simulated the body's blood flow. They removed the endothelium in half the blood vessels, to simulate what happens in soft tissue trauma that causes massive bleeding. The researchers left the endothelium intact in the second group of blood vessels.
When the researchers administered a drug that blocks CO, they found that the vessels with the intact endothelium di
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Contact: Christine Guilfoy
cguilfoy@the-aps.org
301-634-7253
American Physiological Society
6-Apr-2006