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Figure 1 Hypoxia Detection With Pimonidazole in Human Carotid Endarterectomy

(A) Hypoxia (pimonidazole immunoreactivity) is present in the center of an advanced human carotid atherosclerotic plaque, but not in the media. Inset shows hematoxylin and eosin staining. (B) A serial section of panel A shows that CD68-positive macrophages colocalize with hypoxia. (C) Macrophage regions of the lesion from panel A show extensive hypoxia, whereas the cap shows mild or no hypoxia. (D) Hypoxia is present in CD68-positive macrophages (inset) at 20 to 30 µm from the lumen. (E) Hypoxia is absent in CD68-positive macrophages (inset) of a plaque shoulder segment (pathological intimal thickening). (F) Hypoxia is present in an atherosclerotic plaque segment with intimal thickening, more specifically in a few CD68-positive macrophages (inset). (G) The immunoreactivity score of hypoxia (open bars) and CD68 (solid bars) is increased in stable and ruptured atherosclerotic lesions versus early lesions (*p < 0.05 vs. early; stable vs. ruptured is not significant). L = lumen.