The role of chemokine CCL5/RANTES and metalloproteinase-9 as inflammatory modulators in symptomatic internal carotid artery stenosis.

Abstract

Up to 80% of all ischemic strokes (IS) attributed to internal carotid athero-occlusive artery stenosis (ICAS) are related to a thromboembolic mechanism. One athero-occlusive ischemic event increases the risk for ischemia in another vascular territory, resulting from inflammation within the atherosclerotic plaque induced by cytokines. Thus, ultrasonographic characteristics of vulnerable plaques in ICAS, including plaque echolucency and ulceration might correspond to cytokine activity. The present study aimed to investigate the associations between serum cytokines and atherosclerotic plaque characteristics and the 3-year risk of a major adverse coronary and carotid ischemic event (MACCE) in symptomatic patients treated for ICAS. Plaque characteristics on ultrasonography, serum levels of C-C motif chemokine ligand 5 (CCL5)/regulated on activation, normal T-cell expressed and secreted (RANTES), metalloproteinase-9 (MMP-9), interleukin-6 (IL-6), transforming growth factor beta (TGF-β), C-X-C motif chemokine ligand 16 (CXCL16), FAS ligand (FASL) and high sensivity C-reactive protein (hs-CRP) were analyzed in 103 symptomatic patients with ICAS prior to carotid revascularization. The incidence of MACCE: cardiovascular death (CVD), myocardial infarction (MI) and recurrent ischemic stroke (IS) were recorded prospectively for up to 5 years (median 37; IQR 21 - 40 months). Echolucent plaques, in comparison to echogenic plaques, displayed lower median levels of RANTES (P = 0.042) but higher median levels of IL-6 (P = 0.039). There was no relationship between plaque characteristics and median levels of MMP-9, TGF β, CXCL16, FASL, or hs-CRP (P = NS). During follow-up, MACCE occurred in 15 (14.6%) patients. Univariate Cox proportional hazard analysis indicated median RANTES levels < 45.5ng/mL (hazard ratio (HR) = 3.95; 95%CI = 1.10 - 14.2; P = 0.035), MMP-9 > 0.6 μg/mL (HR 4.5; 95%CI = 1.4 - 13.9; P = 0.009), renal impairment (HR 3.48; 95%CI = 1.29 - 9.34; P = 0.013) as potential MACCE risk factors. On multivariate Cox proportional hazard analysis, MMP-9 > 0.6 μg/mL and RANTES < 45.5 ng/ml were associated with a 4.72-fold (95%CI = 1.3 - 17.0; P = 0.017) and a 3.8-fold risk increase (95%CI = 1.07 - 13.89; P = 0.038) of MACCE. Kaplan-Meier analysis showed significant differences in MACCE-free survival rates depending on RANTES and MMP-9 median levels. We conclude that serum RANTES, IL-6, and MMP-9 were associated with plaque vulnerability and predicted adverse MACCE in patients treated for ICAS.