Endothelial dysfunction promotes atherogenesis, vascular inflammation, and thrombus formation. Reendothelialization after angioplasty is required in order to prevent stent failure. Previous studies have highlighted the role of 2-arachidonoylglycerol (2-AG) in murine experimental atherogenesis and in human coronary artery disease. However, the impact of 2-AG on endothelial repair and leukocyte-endothelial cell adhesion is still unknown.
Endothelial repair was studied in two treatment groups of wildtype mice following electrical injury of the common carotid artery. One group received the monoacylglycerol lipase (MAGL)-inhibitor JZL184, which impairs 2-AG degradation and thus causes elevated 2-AG levels, the other group received DMSO (vehicle). The effect of 2-AG on human coronary artery endothelial cell (HCAEC) viability, leukocyte-endothelial cell adhesion, surface expression of adhesion molecules, and expression of endothelial NO synthase (NOS3) was studied in vitro.
Elevated 2-AG levels significantly impaired reendothelialization in wildtype mice following electrical injury of the common carotid artery. In vitro, 2-AG significantly reduced viability of HCAEC. Additionally, 2-AG promoted adhesion of THP-1 monocytes to HCAEC following pre-treatment of the HCAEC with 2-AG. Adhesion molecules (E-selectin, ICAM-1 and VCAM-1) remained unchanged in arterial endothelial cells, whereas 2-AG suppressed the expression of NOS3 in HCAEC.
Elevated 2-AG levels hamper endothelial repair and HCAEC proliferation, while simultaneously facilitating leukocyte-endothelial cell adhesion. Given that 2-AG is elevated in patients with coronary artery disease and non-ST-segment elevation myocardial infarction, 2-AG might decrease reendothelialization after angioplasty and thus impact the clinical outcomes.

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