Expression of angiogenic factor thymidine phosphorylase and angiogenesis in human atherosclerosis

In atheroscelerosis, leukocyte migration into the plaque is thought to occu r across the endothelium of the arterial lumen, However, intraplaque microv essels have been noted. While the significance of, and stimuli for these ar e uncertain, it seems possible that they may represent a second portal of e ntry for leukocytes into the plaque. This study performed a basic character ization of intraplaque microvessels and tested the hypothesis that the nove l angiogenic factor thymidine phosphorylase (TP) is expressed in atheroscle rosis, Immunocytochemistry was performed on aortic and coronary plaques and morphometry on coronary plaques. In plaques from both sites, macrophages, foam cells, and giant cells were immunoreactive for the angiogenic factors TP and vascular endothelial growth factor. Venule-like intraplaque microves sels expressed endothelial leukocyte adhesion molecules HLA-DR and ICAM-1, in contrast to the endothelium overlying the plaque. In coronary plaques, t here was a correlation between severity of stenosis and plaque microvascula r density, These results are consistent with a role for plaque macrophage/f oam cell TP in stimulating plaque angiogenesis, While attention has focused on dysfunction of the endothelium overlying the plaque, microvascular endo thelium may also represent a portal of entry for leukocytes into establishe d plaques. Copyright (C) 2000 John Wiley & Sons, Ltd.