Histopathologic features of degenerative aortic valve and its mechanisms

Abstract To explore the related pathogenesis of degenerative aortic valvular disease by observing the histopathological changes of aortic valves from patients with aortic degenerative stenosis and compare the results with those controls with normal aortic valves. Between May 2009 and May 2010, 22 cases of degenerative calcified aortic valves from patients with aortic valve stenosis undergoing aortic valve replacement (14 males, 8 females, mean age: (66 ± 6) years) and 6 cases of normal aortic valves from those with dissection undergoing Bentall operation (4 males, 2 females, mean age: (43 ± 5) years) were collected. The results of hematoxylin and eosin staining and immunohistochemical examinations were used to observe the histological features of degenerative aortic valves and elucidate the related pathogenesis of degenerative aortic valvular disease. Degenerative aortic valve leaflets became thickened. Calcification appeared in aortic side of valve leaflets. Inflammatory infiltrate, angiogenesis, cholesterol crystals, foamy cell aggregation, diffuse and nodular calcification could be seen in subendocardial space of degenerative aortic valve leaflets. No expression of Osterix (OSX) or nuclear factor of activated T-cells 1 (NFATc1) was observed in normal valves. In contrast, the expressions of OSX and NFATc1 showed nuclear immunostaining in degenerative aortic valves. Immunohistochemical staining was graded from 0 to 3. And the expression of OSX was present in 1(4.5%), 1(4.5%), 8(36.4%) and 12 cases (54.5%) respectively in calcified areas, that of OSX in 4(18.2%), 6(27.3%), 7 (31.8%) and 5 cases (22.7%) respectively in non-calcified areas, that of NFATc1 in 1 (4.5%), 1 (4.5%), 8 (36.4%) and 12 cases (54.5%) respectively in calcified areas, that of NFATc1 in 4 (18.2%), 6 (27.3%), 8 (36.4%) and 4 cases (18.2%) respectively in non-calcified areas. The expressions of OSX and NFATc1 in calcified areas were higher than those in non-calcified areas (χ(2) = 8.320, P = 0.040 and χ(2) = 9.371, P = 0.025 respectively). Unlike in normal valves, inflammatory infiltrate, lipid deposition, angiogenesis and bone regulatory factors appear in degenerative aortic valves. And inflammatory infiltrate, lipid deposition, angiogenesis and ossification may be involved in the degenerative calcified aortic stenosis.