Common virus may spur high blood pressure

Researchers at Beth Israel Deaconess Medical Center (BIDMC) claim to have found that the cytomegalovirus (CMV), a common viral infection affecting vast population globally, triggers inflammation in blood vessels, causing high blood pressure.

Experts also found that the virus led to the development of atherosclerosis, or hardening of the arteries, when coupled with other risk factors for heart disease.

"CMV infects humans all over the world," explains lead researcher Clyde Crumpacker, MD, an investigator in the Division of Infectious Diseases at BIDMC and Professor of Medicine at Harvard Medical School. "This new discovery may eventually provide doctors with a whole new approach to treating hypertension, with anti-viral therapies or vaccines becoming part of the prescription."

How the research was conducted
To reach their findings, Crumpacker and colleagues carried out two experiments involving laboratory mice.

In one experiment, they examined four groups of lab mice. Two groups of animals were fed a standard diet and two were fed a high-fat diet. After the four-week follow-up, the researchers infected one group of the mice from the standard diet group and another group from fatty diet group with the CMV virus.

After six weeks, mice in both the infected groups had elevated blood pressure, but 30 percent of CMV-infected mice in the high-cholesterol diet group also exhibited signs of atherosclerosis.

"This strongly suggests that the CMV infection and the high cholesterol diet might be working together," Crumpacker said.

In another experiment of kidney cells in infected mice, Crumpacker and colleagues found high levels of the enzyme renin, a risk factor for high blood pressure. Similar rate of the enzyme was found in human blood vessel cells infected with CMV.

Crumpacker, who reported his findings in the May 15, 2009 issue of PLoS Pathogens, said more research is needed to establish the role of viruses in causing heart disease.

About High Blood Pressure
High blood pressure, also referred to as hypertension, HTN or HPN, is a medical condition in which the blood pressure is chronically elevated. Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysm, and is a leading cause of chronic renal failure.

Hypertension, also called “silent killer”, can be classified either essential (primary) or secondary. Essential hypertension indicates that no specific medical cause can be found to explain a patient's condition. Secondary hypertension indicates that the high blood pressure is a result of another condition, such as kidney disease or tumors.

What is CMV
Cytomegalovirus is a member of the herpes virus family, and affects all age groups. The virus is the source of congenital infection, mononucleosis, and severe infection in transplant patients. CMV is a lifelong infection, but most of the sufferers will never even know they have it.