To explore potential therapeutic targets for diabetic vascular complications, we first conducted an unbiased screen at the protein level with lower extremity vessels from non-diabetic control individuals and from patients with type 2 diabetes by LC-MS/MS (liquid chromatography-tandem mass spectrometry). A total of 1093 proteins were identified by MS, of which 116 proteins were differentially expressed (false discovery rate q-value < 0.05; fold change > 1.5 or < 1/1.5) in the 3 diabetic samples (DM) compared with 3 non-diabetic controls (Non-DM), including 92 upregulated and 24 downregulated proteins.