Cellular response of human cardiac fibroblasts to mechanically simulated aortic regurgitation.

Myocardial fibrosis has been identified in biopsy specimens from catheterization and valve replacement surgery in patients with severe chronic aortic regurgitation (AR). While characterization of these extracellular matrix (ECM) alterations has been incomplete in humans, fibrosis also has been identified in chronic severe experimentally created AR, in which ECM composition features abnormal fibronectin/glycoprotein production, with normal collagen content. Virtually identical ECM variations have been induced when normal rabbit cardiac fibroblasts (CF) are subjected in culture to cyclic mechanical strain mimicking that found in the left ventricle (LV) in severe AR.