LOCALIZATION OF PROTEIN-Z IN VASCULAR-LESIONS OF PATIENTS WITH ATHEROSCLEROSIS

Background. The deposition of protein Z was investigated in atheroscle rotic vascular lesions of patients with diabetes mellitus or atheroscl erotic vascular disease without diabetes in comparison to controls. Pa tients and methods: Protein Z antigen was evidenced by immunohistochem istry in arteries of 5 healthy control patients, 11 diabetic patients with arterio-occlusive disease and 7 patients suffering from arterio-o cclusive disease without diabetes. For immunohistochemistry, a commerc ially available antibody was taken as first antibody, and Immunopositi vity was evaluated independently by two investigators (J. G.; I. K.) a s negative (0), positive (+) and strongly positive (++). The results w ere assessed by the Whitney-Mann-Wilcoxon test. Results: Macrovascular endothelial cells were stained positive for protein Z in all arteries studied. Arteries of controls did not show significant immunopositivi ty in cells other than macrovascular endothelial cells, while the micr ovascular endothelial cells of control arteries were largely negative. The proliferating subendothelial space in atherosclerotic vascular le sions showed significant immunopositivity for protein Z. In contrast t o control arteries, the microvascular endothelial cells of the prolife rating areas stained positive. The staining pattern of the subendothel ial space was similar in atherosclerotic vessels independent of the ri sk factor for atherosclerosis. Plaques were immunopositive for protein 5 too. Conclusions: Protein Z is present in atherosclerotic vascular lesions of diabetic and non-diabetic patients, but not in the subendot helial space and microvascular endothelial cells of healthy controls. Since protein Z-positivity was detected in microvascular endothelium a s well as In extra-vascular deposits around plaques, it may play a rol e in the development of these lesions.