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AP-1 Protein Controls the Formation of Varicose Veins
Varicose veins, sometimes referred to as "varices" in medical jargon, are usually just a cosmetic problem if they occur as spider veins. In their advanced stage, however, they pose a real health threat. In people with this widespread disorder, the blood is no longer transported to the heart unhindered, but instead pools in the veins of the leg. This is because the vessel walls or venous valves no longer function adequately. Dr. Thomas Korff and his group at the Division of Cardiovascular Physiology (Director: Professor Markus Hecker) of Heidelberg University's Institute of Physiology and Pathophysiology have now shown that the pathological remodeling processes causing varicose veins are mediated by a single protein (AP-1). As a response to increased stretching of the vessel wall, this protein triggers the production of several molecules promoting changes in wall architecture. The paper, published in the October 2011 issue of The FASEB Journal, may offer a possibility for using drugs to decelerate the formation of, or even prevent, new varicose veins. Previously, no suitable experimental systems existed for studying the way in which these changes in the cells of the blood vessels are controlled. For their studies, Dr. Korff and his team took advantage of the fact that blood vessels in the mouse ear are clearly visible and are also easily accessible for minor surgical procedures. In order to artificially set off processes that are similar to the formation of varicose veins, they tied off a vein with a thin thread. The elevated pressure in the vessels caused by the pooled blood led to the recognizable remodeling characteristic of varicose veins. In addition, in the affected veins, the cell proliferation rate and the production of MMP-2 increased.