A common virus might be a major cause of high blood pressure, a new study found.
Researchers discovered that cytomegalovirus (CMV), an infection affecting between 60 and 99 percent of adults worldwide, can cause high blood pressure. The study was conducted with mice, but researchers think the link also applies to humans.
"It's estimated that a third of the American population does have high blood pressure," said study leader Clyde Crumpacker, a researcher at Beth Israel Deaconess Medical Center and professor at Harvard Medical School. "In 90 percent of those cases the cause is unclear. There is the possibility that this common viral infection might be a significant cause."
Crumpacker and team found that mice infected with CMV developed higher blood pressure than uninfected mice. What's more, when CMV-infected mice were fed high-cholesterol diets, they had the highest blood pressures of all.
High cholesterol diets and obesity are known to influence high blood pressure, but this is the first time that CMV infection is also implicated. The discovery could lead to better treatments.
"Here is the possibility that maybe high blood pressure could be prevented or treated by antiviral therapies or a vaccine," Crumpacker told LiveScience. "That could have major public health advantages for the American people."
The finding also fits into a larger pattern of research revealing links between common viruses or bacterial infections and major health problems. For example:
- The discovery that human papillomavirus (HPV) causes cervical cancer was a major breakthrough in the 1970s. Now a vaccine against the virus is seen as a significant advance in preventing the disease.
- Ulcers, once thought to be caused by stress, were recently discovered to be the result of Helicobacter pylori bacteria. The National Institutes of Health estimates that more than 90 percent of all cases of gastritis and ulcers are caused by this infection.
- The human adenovirus 36 (AD-36) was recently found to contribute to obesity by encouraging fat cells to replicate.
- The Coxsackie B4 virus is linked to the development of childhood Type 1 diabetes.
"It's likely that we're going to continue to find more and more links like this," Crumpacker said.
As with many of these connections, the virus associated with high blood pressure is probably a contributing factor, instead of the sole cause, of the disease. Diet and genetic predisposition are also known to be factors influencing high blood pressure (also called hypertension).
"It does sound reasonable, but it could only be one of many factors involved in hypertension," said Sylvia Smoller, a professor of epidemiology and population health at Albert Einstein College of Medicine at Yeshiva University in New York. She also cautioned that the results will need to be confirmed in humans, not just in mice.
The researchers think the connection applies to humans because they also conducted trials with human cell cultures. They found that when the cells were infected with CMV, they created a protein called renin that is known to contribute to high blood pressure.
Many people have CMV without knowing it. The virus is transmitted through sharing of bodily fluids, and can be passed on from a pregnant woman to her baby. Often it exists latent in the body without any symptoms, but if an infected person's immune system is compromised, it can cause problems, such as blockage of arteries in cardiac transplant patients.