Fig. 1.

A) Macroscopic aspect of AKU aortic valve showing a rough surface of the leaflets and ochronotic pigmentation on the surface. A thickening of the central areas of the cusps with nodule-like structures is visible (arrow). B) Light microscopy (hematoxylin and eosin staining) examinations of AKU aortic valve with intense inflammatory cell infiltrate that includes large cells macroscopically corresponding to macrophages (arrows). Magnification 20 ×. C) Congo Red staining of AKU aortic valve amyloid deposits. Left: unpolarized light. Valve tissue was ever stained red (“congophilic”); Right: polarized light. The pigmented areas (arrows) were also birefringent, indicating overlapping of ochronosis and amyloid. Magnification 40 ×. D) SAA was present in AKU aortic valve amyloid deposits. Positive staining for SAA-amyloid was particularly intense in correspondence of ochronotic pigmentation. Magnification 20 ×. E) Immunoreactivity for 4-HNE in AKU aortic valve leaflet. The presence of 4-HNE in the AKU valve was uniformly diffused and the distribution of 4-HNE-positive area was perfectly superimposing to ochronotic pigmented areas. The presence of lipid peroxidation and ochronotic pigment was found to be strictly related to areas of lymphocytes accumulation. Magnification 20 ×.