Role of the ubiquitin-proteasome system in carotid plaque instability in diabetic patients.

In order to define the role of the ubiquitin-proteasome system in atherosclerotic plaque rupture in patients with type 2 diabetes mellitus (T2DM), we evaluated the amount of this system, of the main inflammatory cells, of the collagen content and some indexes indicative of oxidative stress in the carotid plaques of both diabetic and non-diabetic asymptomatic patients. Plaques were obtained from 31 type 2 diabetic and 27 non-diabetic patients undergoing endoterectomy. Both were examined for macrophages, T-lymphocytes, ubiquitin/proteasome 20S activity, NFkB, IkB-b, nitrotyrosine, matrix metalloproteinase-9 (MMP-9) and collagen.