Release kinetics of inflammatory biomarkers in a clinical model of acute myocardial infarction

Abstract

Rationale: Inflammation in the setting of acute myocardial infarction (MI) has been linked to risk stratification; however, the release kinetics of inflammatory biomarkers in patients with acute MI has been difficult to establish.

Objective: The aim of this study was to determine the kinetics of changes in the levels of several biomarkers specifically linked to inflammation after transcoronary ablation of septal hypertrophy, a procedure that mimics acute MI.

Methods and results: We analyzed release kinetics of C-reactive protein, high-sensitivity C-reactive protein, interleukin-6, soluble CD40 ligand, and peripheral blood leukocyte subsets in patients (n=21) undergoing transcoronary ablation of septal hypertrophy. Blood samples were collected before transcoronary ablation of septal hypertrophy and at various times after transcoronary ablation of septal hypertrophy. Serum levels of C-reactive protein were increased at 24 hours (1.0 mg/dL [interquartile range [IQR], 0.7-1.75] versus 0.2 mg/dL [IQR, 0.1-1.05] at baseline [BL]; P<0.001), whereas high-sensitivity C-reactive protein increased as early as 8 hours (2.68 mg/L [IQR, 1.23-11.80] versus 2.17 mg/L [IQR, 1.15-5.06] at BL; P=0.002). Interleukin-6 was significantly increased at 45 minutes (2.59 pg/mL [IQR, 1.69-5.0] versus 1.5 pg/mL [IQR, 1.5-2.21] at BL; P=0.002), and soluble CD40 ligand was significantly decreased at 60 minutes (801.6 pg/mL [IQR, 675.0-1653.5] versus 1750.0 pg/mL [IQR, 1151.0-2783.0] at BL; P=0.016). Elevated counts of polymorphonuclear neutrophils were detectable at 15 minutes, with a significant increase at 2 hours (6415 cells/μL [IQR, 5288-7827] versus 4697 cells/μL [IQR, 2892-5620] at BL; P=0.004). Significant monocytosis was observed at 24 hours (729 cells/μL [IQR, 584-1344] versus 523 cells/μL [IQR, 369-701] at BL; P=0.015).

Conclusions: Interleukin-6 and neutrophil granulocytes showed a continuous rise at all prespecified time points after induction of MI. Our results provide valuable additional evidence of the diagnostic value of inflammatory biomarkers in the setting of early acute MI.

Keywords: acute myocardial infarction; inflammation; leukocytes.