"We were able to measure blood pressure directly in the arteries of the mice," Crumpacker said. The studies showed increased blood pressure in the infected mice after six weeks, but not in the uninfected group. It also showed that 30 percent of the infected mice in the high-cholesterol group developed atherosclerosis as well as high blood pressure.
There are several possible mechanisms for the pressure-raising effect of CMV, Crumpacker said. One is that it increases the activity of renin, an enzyme associated with high blood pressure. The study showed that CMV also increases activity of angiotensin 11, a protein involved in high blood pressure.
Most cases of high blood pressure in humans are of unknown origin, Crumpacker said. "Ninety-eight percent of the time, we don't know what the cause is," he said. If CMV infection is established as a cause -- something that requires much more research -- the way would be open for better methods of prevention and treatment, Crumpacker said.
"This is very exciting and important work," said Dr. Mark R. Schleiss, who holds the American Legion chair of pediatric infectious disease at the University of Minnesota and is a leading figure in the drive to develop a CMV vaccine.
"It is virtually certain that cytomegalovirus infection makes at least some contribution to cardiovascular disease in people," Schleiss said. "Obviously, cytomegalovirus is not the whole picture. There are other issues, including smoking, physical activity and diet. But this extends our body of knowledge about the role cytomegalovirus infection can play, and it is an important role, in cardiovascular disease."
The effort to develop a CMV vaccine has concentrated on childbirth, since infection during pregnancy is the leading cause of mental retardation and deafness in children, Schleiss said. "Now there is an urgency to develop a vaccin
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