High plasma levels of the soluble receptor for advanced glycation endproducts in patients with symptomatic carotid atherosclerosis

Background Advanced glycation endproducts (AGEs), particularly carboxymethyl(lysine)-adducts (CML), exert part of their cellular effects by binding to a receptor, named receptor for AGEs (RAGE). The soluble form of this receptor (sRAGE) has been shown to have an athero-protective role. We hypothesized the existence of a relationship between the AGE-RAGE axis and the occurrence of symptoms related to carotid atherosclerosis in nondiabetic conditions. Materials and methods We evaluated plasma levels of CML and sRAGE (by ELISA), and tissue levels (tAGEs and tRAGE, semiquantitatively, by immunohistochemistry) in endarterectomy carotid plaque tissue in 29 nondiabetic patients. At the time of surgery, 10 patients were asymptomatic and 19 were symptomatic. Results Plasma levels of sRAGE were higher in symptomatic patients than in asymptomatic patients [median (interquartile range): 676 (394-858) pg mL‾ overline1 vs. 347 (284-479) pg mL‾ overline1, P = 0.009]. In symptomatic patients, plasma levels of sRAGE correlated positively with CML (r = 0.60, P 0.01), C-reactive protein (CRP) (r