Changes in mitral valve with age averaged across 200 mitral valve samples. Trends include decreasing cellularity and increasing fibrosis and collagen degradation, lipid accumulation and calcification. Reprinted from Sell, S., Scully, R. E. (1965). Aging changes in the aortic and mitral valves: histologic and histochemical studies, with observations on the pathogenesis of calcific aortic stenosis and calcification of the mitral annulus. Am J Pathol, 46 (3), 345–365 with permission from Elsevier.