Amyloidosis, Inflammation, and Oxidative Stress in the Heart of an Alkaptonuric Patient

Figure 3

TEM observation of AKU aortic valve. (a) Large deposits of extracellular ochronotic pigment associated with areas of valvular calcification (arrows). Bar 2 μm. (b) Pathological alterations and calcification (white arrow) involving surface endothelium with cells disgregation and sprinkled Golgi complex and ER (black arrows). Bar 1 μm. (c) Interweaving networks of collagen fiber bundles (white circle) and aggregates of extracellular ochronotic pigment appeared to be in locations of necrotic cells (black arrow). Bar 1 μm. (d) Intracellular ochronotic pigment (black arrow) and an example of apoptotic cell with condensed chromatin and disrupted mitochondrion (white arrow). Bar 200 nm. (e), (f), and (g) ECM organization is disrupted and ECM trilaminar stratification is lost as evidenced by disorganized and fragmented collagens and elastin fibres strictly interconnected to pigment “squirts” (white circle and arrows); in (f) a necrotic cell is shown with multiple dysmorphic mitochondria. (e) Bar 1 μm; (f) bar 500 nm; (g) bar 200 nm; (h) bundles of amyloid fibrils nearby ochronotic deposits. Bar 100 nm.