Platelet expression of stromal-cell-derived factor-1 (SDF-1): An indicator for ACS?

Background: Acute coronary syndrome (ACS) along with myocardial ischemic injury are the leading causes for chest pain. Platelet surface expression of stromal-cell-derived factor-1 (SDF-1) is enhanced during ischemic events and may play an important role in trafficking hematopoietic progenitor cells for tissue regeneration and neovascularization. This study examined the platelet surface expression of SDF-1 in patients with chest pain. Methods: We consecutively evaluated 1000 patients, who were admitted to the emergency department with chest pain. Platelet surface expression of GPIb and SDF-1 was determined by two-color whole blood flow cytometry. Results: Patients with ACS showed significantly enhanced SDF-1 expression on admission compared to patients with other causes such as stable angina pectoris (SAP) and other origin of chest pain (CPO) (ACS vs. SAP/CPO (mean fluorescence intensity (MFI) +/- SD): 39.7 +/- 26.3 vs. SAP: 37.6 +/- 31.5; P=0.045; arterial hypertension: 27.3 +/- 12.7; P=0.003; orthopedic disease: 22.1 +/- 6.5; P=0.014; pulmonary embolism: 26.6 +/- 19.1; P=0.003; Da Costa's syndrome: 22.1 +/- 12.5; P=0.021; inflammatory cardiomyopathy: 19.8 +/- 11.5; P=0.025). Logistic regression analysis showed that surface expression of platelet SDF-1 was significantly associated with ACS (P=0.026), however, the superiority of troponin-I in predicting ACS remains on a high level (P=0.001). Areas under the curve of receiver operating characteristic analysis revealed 0.718 (95% confidence interval (CI): 0.680-0.757) using SDF-1, and 0.795 (95% CI: 0.760-0.829) applying troponin-I baseline serum levels. Patients with enhanced SDF-1 levels (cutoff: MFI >= 27.7) had a 1.4-fold relative risk (95% CI: 1.17-1.52) for ACS. Conclusions: Platelet SDF-1 surface expression was significantly enhanced in patients with ACS compared to SAP or CPO. Determination of platelet SDF-1 may be useful as an early additional biomarker for cardiovascular risk stratification. (C) 2011 Elsevier Ireland Ltd. All rights reserved.