DALLAS, August 11 -- People with high blood pressure have elevated blood levels of collagen, a protein, which may help explain why these individuals are at risk for heart failure as well as kidney and other organ failure, according to a study in today's Circulation: Journal of the American Heart Association.
How high blood pressure contributes to organ failure has not been understood. However, researchers from the University of Navarra School of Medicine in Pamplona, Spain found excess collagen and not enough of the chemical that breaks it down in individuals with high blood pressure. The study also provides a possible reason for the effectiveness of ACE-inhibitor drugs: They can help prevent the build-up of collagen and, in turn, the failure of these organs.
Collagen is a vital "building block" that contributes to the shape and function of the skin, heart, blood vessels and other organs. When synthesis exceeds degradation, there is a net accumulation of collagen that can eventually become fibrosis.
When blood vessels become stiff because of fibrosis, the heart works harder to keep blood flowing through the vessels and blood pressure increases. As fibrosis progresses, cells in the heart and vessels are encased in a "cement-like" collagen mesh. The heart and vessels become stiffer, and their cells no longer can function properly.
"Picture giant mastodons, large, perfectly healthy animals. They are like the enlarged heart muscle cells caused by high blood pressure, who are trapped in tar, not unlike fibrous tissue," says Karl T. Weber, M.D., of the University of Missouri Health Sciences Center. His editorial about the study appears in today's issue of Circulation: Journal of the American Heart Association. "Because of this unfriendly environment, these mastodons are unable to move -- much like heart muscle cells unable to properly contract -- and become vulnerable."