Screening and Identification of Pregnancy Zone Protein and Leucine‐Rich Alpha‐2‐Glycoprotein as Potential Serum Biomarkers for Early‐Onset Myocardial Infarction using Protein Profile Analysis

Purpose The present study aims to discover novel serum biomarkers of early‐onset myocardial infarction (MI) using proteomic analysis. Experimental design In the first stage, the iTRAQ‐coupled LC–MS/MS technique is utilized to investigate protein profiles of patients with early‐onset MI. In the second stage, these candidate proteins are validated using ELISA. Results A total of 538 proteins are quantified, with pregnancy zone protein (PZP), leucine‐rich α‐2‐glycoprotein (LRG) and Apolipoprotein C‐I (Apo C‐I) being upregulated and Apolipoprotein A‐I (Apo A‐I) and Apolipoprotein A‐IV (Apo A‐IV) downregulated in early‐onset MI patients. Results from the validation stage demonstrate that the serum concentrations of PZP and LRG are significantly increased in the early‐onset MI group. The correlation between the concentrations of C‐reactive protein (CRP) and the two candidate biomarkers is positive. Area under the curve values used to diagnose early‐onset MI for LRG and PZP are 0.939 and 0.874, respectively. Conclusions and clinical relevance Five differential serum proteins are identified in early‐onset MI using proteomic analysis. Lipoprotein‐related biomarkers further demonstrate the close relationship between lipid metabolism and the disease. Inflammation‐associated LRG and PZP may be novel biomarkers of the disease. In addition, changes in these proteins may partly reveal the possible mechanisms in the pathogenesis and pathophysiology of early‐onset MI.