Science News

Virus to blame for blood pressure

US Scientists have discovered that a common human viral infection may be linked to hypertension, also known as high blood pressure.

Writing in PLoS Pathogens, Beth Israel Deconess Medical Center researcher Clyde Crumpacker and his team infected mice with the rodent equivalent of CMV (cytomegalovirus), which infects 80% of human adults.  They found that, compared with uninfected controls, the CMV-exposed animals had significantly higher blood pressure in the weeks after the infection.

They also fed a second group of mice on a high-fat diet and infected half of them with the virus.  In the CMV-exposed group the animals again developed hypertension but also showed signs of early atherosclerosis (arterial disease).

To find out why, the team studied the animal's blood vessels and found that the virus was establishing a persistent infection in the vessel wall that led to the production of inflammatory hormones called cytokines including IL-6, TNF-alpha and MCP-1, which have been linked previously to vascular disease.  The team also found increases in the activity of two genes that directly control blood pressure - renin and angiotensin.

Next, to find out whether the results also apply to humans the team infected human umbilical cord blood vessels with human CMV with the same results.  These findings are important because CMV is part of the herpes virus family, members of which characteristically establish life-long "latent" infections, meaning that CMV is well-placed to provoke long-term injury to blood vessels that could lead to vascular disease.  The next step will be to discover whether there is a real association between human onset of hypertension and CMV infection, which increases in prevalence with increasing age, just like blood pressure diagnoses...

17th May 2009