Obscurin and Clusterin Elevation in Serum of Acute Myocardial Infarction Patients

Abstract

We discovered new biomarker candidates for acute myocardial infarction (AMI) using micro LC and accurate mass spectrometry. Two serum samples were pooled and used for biomarker screening. UHPLC-LTQ-Orbitrap analysis was used with data-dependent acquisition followed by Sequest search. Six biomarker candidates were selected after fold change analysis of peptides in AMI patient samples compared to healthy controls. Literature search results were reflected. The six biomarker candidates were characterized and quantified using multi reaction monitoring using synthesized peptides or trypsin digested protein standards. Levels of obscurin, alpha-1-acid glycoprotein 1, and clusterin were significantly increased (p < 0.001) in AMI patient samples compared to levels in healthy controls, while those of antithrombin III and fibrinogen beta were not. We confirmed the diagnostic performance of obscurin and clusterin as biomarker candidates for AMI using commercial ELISA kits. Receiver operating characteristic results showed that obscurin and clusterin showed highest sensitivity and specificity for AMI diagnosis together with troponins by both of multi-reaction monitoring analysis and ELISA.