Figure 2.

Chronic vascular inflammation and adventitial vasa vasorum expansion in irradiated human arteries. Immunofluorescent staining on the arterial wall is positive for 5-LO in irradiated arteries. A–E) 5-LO–positive cells localized around the expanded vasa vasorum in the adventitia of irradiated (XRT) (C–E), but not in nonirradiated (0 XRT) (A, B) arteries. K–O) Invasion of macrophages into the adventitia was observed in irradiated arteries only. F–J) VWF staining was confined to vasa vasorum in the adventitia of irradiated arteries and not observed in the adventitia of nonirradiated controls from the same patients. Blue fluorescence, DAPI; red fluorescence, 5-LO; green fluorescence, VWF/CD68.