HMGB1 Expression Level in Circulating Platelets is not Significantly Associated with Outcomes in Symptomatic Coronary Artery Disease

BACKGROUND/AIMS: Platelets express high-mobility group box 1 (HMGB1), a damage-associated molecular pattern molecule (DAMP) that triggers thrombosis and inflammation when present in extracellular space. The role of platelet-derived HMGB1 in coronary artery disease (CAD) remains unexplored. METHODS: In a cohort study, we measured the expression of HMGB1 on the surface of circulating platelets in 183 patients with symptomatic CAD (stable CAD: n=80, acute coronary syndrome, ACS: n=103) at the time of percutaneous coronary intervention. All patients were tracked for course of left ventricular ejection fraction (LVEF), all-cause death (ACD), and myocardial infarction (MI) for 360 days after study inclusion. RESULTS: Platelet HMGB1 expression did not significantly differ between stable CAD, unstable CAD, non-ST segment elevation myocardial infarction (NSTEMI), and ST segment elevation myocardial infarction (STEMI). Moreover, platelet HMGB1 did not significantly correlate with LVEF, neither at baseline nor at 6 months follow-up of the MI subgroup, and did not exert any significant effect on outcome (composite of ACD and/or MI as well as single events ACD and MI). Cumulative event-free survival of patients was not significantly different between HMGB1 levels above the median and HMGB1 levels below or equal to the median. CONCLUSION: These findings suggest that HMGB1 expressed on the surface of circulating platelets in patients with symptomatic CAD may not serve as a prognostic biomarker for this disease state.