Human endothelial lecitin-like oxLDL receptor-1 (LOX-1) expression is not associated with impairment of endothelium-dependent vasoreactivity in conduit vessels

The cellular uptake of oxidized low density lipoprotein (ldl) is mediated through the oxidized ldl receptor-1,lox-1. we investigated whether circulating factors link lox-1 expression in endothelial cells and impaired endothelium-dependent vasoreactivity (edvr) as functional indicator of atherogenesis. edvr was measured as flow-mediated dilation (fmd) of the brachial artery in 27 patients with a known history of cardiovascular disease. human umbilical vein endothelial cells (huvec) were incubated with bradykinin or prostacyclin in the presence of tumour necrosis factor-alpha (tnf-α) or with serum of each patient for four hours. total mrna and protein extracts were analysed for lox-1 and enos expression relative to the expression in medium-treated cells and corrected for gapdh expression. results: prostacyclin and bradykinin did not modulate lox-1 basal expression but were able to prevent significantly the up-regulation of lox-1 expression by tnf-α,in huvec in vitro. impaired edvr was associated significantly with reduced endothelial nitric oxide synthase (enos) protein expression in huvec (r=0.788,p<0.001),diabetes (p=0.024),and smoking status (yes/no,p=0.047). in contrast,no such association was established with lox-1 mrna (r=0.292,p=0.138) or with lox-1 protein expression in huvec (r=0.201,p=0.312). conclusions: using a combination of in vitro experiments with in vivo measurements,we found no evidence that endothelial lox-1 expression and edvr mediated through circulating factors were associated.