Figure 4 (A) Immunostaining for secreted protein, acidic and rich in cysteine/osteonectin (SPARC) showing localisation to fibroblasts and the extracellular matrix near calcified nodules (purple) (200×). SPARC expression (B) by the endothelium of the leaflet surface (arrow) (100×), (C) by the endothelium of blood vessels under the valve surface (200×), (D) by medium‐sized blood vessels (600×) and (E) by capillaries (1000×). (F) SPARC was expressed in cell islands by mature blood vessels (200 ×) and by (G) multinucleated cells (1000×) that were (H) CD68 positive (macrophages) (1000×). (I) macrophages in cell islands expressed matrix metalloproteinase‐9 (1000×).