Abstract Body (Do not enter title and authors here): Introduction
Insulin growth factor (IGF) binding protein-1 and 2 (IGFBP-1 and 2) are implicated in acute myocardial infarction (AMI) and have been suggested as predictors of mortality and development of heart failure. The IGF axis has been shown to play roles in cell proliferation and apoptosis. We analysed the serum IGFBP-1 and 2 levels in AMI before and after percutaneous coronary intervention (PCI) and correlated this with cardiac magnetic resonance (CMR) imaging to better establish their significance as biomarkers in AMI.

Methods
Patients with AMI who presented to Royal Free Hospital, London, were recruited for proteomic analysis (O link Proximity Extension Immunoassay) at presentation, 24h and 72h following primary PCI. All underwent both admission and follow-up CMR at 6 months to assess for myocardial oedema, left ventricular volumes and function, and assessment of scar.

Results
Proteomic evaluation in 20 AMI patients (male 95%; median age 59) revealed significant reduction in the average IGFBP-1 values at discharge compared with presentation, from 5.93 to 4.52 (24% reduction, p=0.003). Conversely, the average IGFBP-2 values at discharge significantly increased from 7.66 to 8.29 (8% increase, p=0.001). Higher discharge IGFBP-2 value was also correlated with increased indexed left ventricle end diastolic volume (LVEDV) at 6-month follow-up (R=0.54, p=0.032).

Discussion
IGFBP-1 and 2 showed significant change following intervention for AMI. IGFBP-1 is a stress hormone, which is directly and indirectly activated by cytokines, dysglycaemia and vasopressin activation. Its subsequent reduction following PCI in AMI indicates relative resolution of inflammation, but this was not correlated with changes in infarct size or LV function at follow-up. IGFBP-2 showed significant upregulation, and higher values at discharge were significantly correlated with increased LDEDV at follow-up, suggesting adverse clinical outcomes within this setting. This data suggests differential roles of IGFBP-1 and 2 in the pathogenesis of AMI.