The aortic valve microenvironment and its role in calcific aortic valve disease.

In calcific aortic valve disease, fibrotic and calcific lesions form focally in the fibrosa layer of the valve leaflets. Layer-specific pathosusceptibility suggests that the fibrosa microenvironment is permissive to pathological development. The cellular microenvironment in the aortic valve is defined by a variety of biomechanical-, biochemical-, and extracellular-mediated factors, some of which are unique to the fibrosa. Growing evidence supports the role of these microenvironmental cues in the local regulation of side-specific valve cell phenotypes and focal pathological alterations, revealing new insights into the cellular and molecular processes that contribute to calcific aortic valve disease.