Abstract 2600: Serum Proteomics Identifies Vitamin D-Binding Protein And Prothrombin As Novel Fingerprints of Coronary Thrombosis in Patients with STEMI
One of the intriguing possibilities offered by proteomics analysis is to define new diagnostic and prognostic biomarkers of coronary artery disease. Accordingly, the aim of the present study was to analyze modifications in the serum proteome after acute myocardial infarction. Serum samples were collected from patients (age 63.8±12.6) with ST-Elevation Myocardial Infarction (STEMI) at 2–11 hours after the onset of typical chest pain and before standard therapy was initiated. The control group included 10 age- and sex-matched normal donors. The serum samples were processed to obtain albumin- and IgG-depleted serum. Then, isotope-coded affinity tag (ICAT) method was employed to label cysteine residues and liquid chromatography-Tandem Mass Spectrometry (LC-MS/MS) analysis was performed to measure the labelled proteins. Ten out of 300 defined and analyzed proteins were identified in 100% of the samples. Interestingly, haptoglobin, alpha-1-antitrypsin and ceruloplasmin were significantly increased in the samples from patients with acute STEMI (N=10) compared to controls (N=10). These data well reproduce similar findings reported in recent studies. However, two novel proteins were identified in patients with AMI. Remarkably, we observed a significant increase of vitamin D-binding protein precursor (VDB) and heavy chain prothrombin precursor in the serum from acute STEMI patients compared to control donors. Western blot analysis confirmed the higher amount of the latter two proteins after STEMI. Interestingly, fresh thrombotic plaques, obtained during primary angioplasty, showed high expression of VDB and prothrombin by RT-PCR and immunohistochemistry, postulating a potential role of VDB and prothrombin in coronary plaque instability and thrombosis. In additional studies in ex vivo human platelets VDB, as well as prothrombin, significantly increased ADP-induced platelet aggregation. In conclusion, the serum proteomics analysis employed in this study was able to identify VDB and prothrombin protein variation as novel indicators of acute STEMI. These data could be relevant to establish specific proteomics-based serum fingerprints for diagnosis and prognosis of acute coronary syndromes.