Histamine H1 type receptor antagonist loratadine ameliorates oxidized LDL induced endothelial dysfunction.

Oxidized LDL (ox-LDL) is one of the major risk factors of atherosclerosis. Endothelial dysfunction caused by ox-LDL is an early event in the pathogenesis of cardiovascular diseases. Preclinical studies have been performed to explore efficient means of preventing endothelial abnormalities. In this study, we revealed that loratadine, a histamine H1 type receptor specific antagonist, possesses a protective effect by relieving ox-LDL-induced endothelial inflammation. Treatment of endothelial cells with ox-LDL induces expression of the H1 receptor. The presence of loratadine in endothelial culture efficiently suppressed ox-LDL-induced attachment of monocytes to endothelial cells, production of ROS and vascular adhesion molecules, and induction cytokines including VCAM-1, E-selectin, TNF-α, IL-6 and IL-8. Mechanistically, we show that loratadine potently blocks ox-LDL-induced JNK activation as well as the AP-1 and NF-κB signaling pathways. Collectively, our data disclose a new role for loratadine in endothelial protection.