Plasmatic biomarkers of inflammation correlate with 18FDG-PET-CT and microembolic signals in patients with carotid stenosis

Abstract

Aim: To determine whether plasmatic biomarkers correlate with 18fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET-CT) and presence of microembolic signals (MES) detected by transcranial Doppler in patients with carotid stenosis.Methods: 18FDG-PET-CT and MES detection was performed in consecutive patients with 50% to 99% symptomatic or asymptomatic carotid stenosis. Uptake index was defined by a target to background ratio (TBR) between maximum standardized uptake value of the carotid plaque and the average uptake of the jugular veins. The analysis of biomarkers included adhesion molecules [intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule 1, P-selectin and E-selectin], interleukins (IL-1, IL-6), chemokines (RANTES, monocyte chemoattractant protein 1), cytokines (tumor necrosis factor α), matrix-metalloproteases (MMP), myeloperoxidase, and lipoprotein-associated phospholipase A2.Results: There were 54 symptomatic and 57 asymptomatic patients. TBR values were significantly higher in the symptomatic compared to the asymptomatic (median 2.1 vs. 1.8, P = 0.002) and in the MES positive (MES+) compared to the MES negative (MES-) group (MES+, n = 19, median 2.3 and MES-, n = 88, median 1.8, P = 0.01). The best threshold for TBR values was of 1.9. We found a significant correlation between higher 18FDG uptake (TBR ≥ 1.9) and the plasmatic levels of chemokine RANTES (P = 0.03) and higher levels of ICAM-1 in MES+ patients (P = 0.03). Interestingly MMP-2 levels were more important in patients with lower TBR values (P = 0.02) and MMP-3 and P-selectin in those who were MES- (respectively P = 0.001 and P = 0.009).Conclusion: In the present study, ICAM-1 was associated with the presence of thrombotically active atherosclerotic plaques, while RANTES mainly correlated with the inflammatory process. MMP-2, MMP-3 and P-selectin levels were more important in patients with stable plaques