Stenotic aortic valves are characterized by atherosclerosis-like lesions, consisting of activated inflammatory cells, including T lymphocytes, macrophages, and mast cells, and of lipid deposits, calcific nodules, and bone tissue. Active mediators of calcification and cells with osteoblast-like activity are present in diseased valves. Extracellular matrix remodeling, including collagen synthesis and elastin degradation by matrix metalloproteinases and cathepsins, contributes to leaflet stiffening. In experimental animals, hypercholesterolemia induces calcification and bone formation in aortic valves, which can be inhibited by statin treatment. The potential of statins to retard progression of aortic valve stenosis has also been recognized in clinical studies; however, the results of such trials have been negative. We have found that angiotensin II-forming enzymes are upregulated in stenotic valves. Thus, angiotensin II may participate in profibrotic progression of aortic valve stenosis and may serve as a possible therapeutic target of the disease.

Based on the original observation in our laboratory, we launched together with the Division of Cardiology at the University of Helsinki (Principal Investigator Professor Markku Kupari), a blinded, randomized, placebo-controlled, prospective study, the aim of which is to determine the influence of effective treatment with Type 1 angiotensin II (Ang II) receptor (AT-1R) antagonist, using candesartan (target dose 16 mg) on stenotic aortic valves. The investigators will specifically quantify whether candesartan attenuates the key pathogenic mechanisms of aortic valve stenosis, namely inflammation, fibrosis, elastin degradation, calcification, and neovascularization.

Selected publications

Syväranta S, Helske S, Laine M, Lappalainen J, Kupari M, Mäyränpää MI, Lindstedt KA, Kovanen PT. Vascular endothelial growth factor-secreting mast cells and myofibroblasts: a novel self-perpetuating angiogenic pathway in aortic valve stenosis. Arterioscler Thromb Vasc Biol. 2010;30:1220-7.

Helske S, Miettinen T, Gylling H, Mäyränpää M, Lommi J, Turto H, Werkkala K, Kupari M, Kovanen PT. Accumulation of cholesterol precursors and plant sterols in human stenotic aortic valves. J Lipid Res. 2008;49:1511-8.

Helske S, Kupari M, Lindstedt KA, Kovanen PT. Aortic valve stenosis: an active atheroinflammatory process. Curr Opin Lipidol. 2007;18:483-91.

Helske S, Lindstedt KA, Laine M, Mäyränpää M, Werkkala K, Lommi J, Turto H, Kupari M, Kovanen PT. Induction of local angiotensin II-producing systems in stenotic aortic valves. J Am Coll Cardiol. 2004;44:1859-66.