The role of endothelial nitric oxide in the anti-restenotic effects of liraglutide in a mouse model of restenosis

• Published in: Cardiovascular diabetology 2017-10, Vol.16 (1), p.122-122, Article 122
• Main Authors: Kushima, Hideki, Mori, Yusaku, Koshibu, Masakazu, Hiromura, Munenori, Kohashi, Kyoko, Terasaki, Michishige, Fukui, Tomoyasu, Hirano, Tsutomu
• Format: Article
• Language: English
• Subjects: AMP-activated protein kinase; Angioplasty; Animals; Antidiabetics; Arginine; Cardiovascular disease; Cell proliferation; Cells, Cultured; Coronary Restenosis - drug therapy; Coronary Restenosis - metabolism; Coronary Restenosis - pathology; Cyclic AMP; Diabetes mellitus; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelial cells; Endothelium; Femoral artery; Femur; GLP-1 receptor agonist; Glucagon; Glucagon-like peptide 1; Human Umbilical Vein Endothelial Cells - drug effects; Human Umbilical Vein Endothelial Cells - metabolism; Humans; Hyperglycemia; Hyperplasia; Hypoglycemic Agents - pharmacology; Hypoglycemic Agents - therapeutic use; Injury analysis; Kinases; Liraglutide - pharmacology; Liraglutide - therapeutic use; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Morphometry; Mouse; Nitric oxide; Nitric Oxide - antagonists & inhibitors; Nitric Oxide - physiology; Nitric-oxide synthase; Original Investigation; Phosphorylation; Protein kinase A; Restenosis; Rodents; siRNA; Smooth muscle; Treatment Outcome; Umbilical vein; Variance analysis
• ISSN: 1475-2840; 1475-2840
• DOI: 10.1186/s12933-017-0603-x

Previous animal studies have shown that glucagon-like peptide-1 receptor agonists (GLP-1RAs) suppress arterial restenosis, a major complication of angioplasty, presumably through their direct action on vascular smooth muscle cells. However, the contribution of vascular endothelial cells (VECs) to this process remains unknown. In addition, the potential interference caused by severe hyperglycemia and optimal treatment regimen remain to be determined. Nine-week-old male C57BL6 (wild-type) and diabetic db/db mice were randomly divided into vehicle or liraglutide treatment groups (Day 1), and subject to femoral artery wire injuries (Day 3). The injured arteries were collected on Day 29 for morphometric analysis. Human umbilical vein endothelial cells (HUVECs) were used for in vitro experiments. One-way ANOVA, followed by Tukey's test, was used for comparisons. In wild-type mice, liraglutide treatment (5.7, 17, or 107 nmol/kg/day) dose-dependently reduced the neointimal area (20, 50, and 65%) without inducing systemic effects, and caused an associated decrease in the percentage of vascular proliferating cells. However, these effects were completely abolished by the nitric oxide synthase (NOS) inhibitor N-omega-nitro-L-arginine methyl ester. Next, we investigated the optimal treatment regimen. Early treatment (Days 1-14) was as effective in reducing the neointimal area and vascular cell proliferation as full treatment (Days 1-29), whereas delayed treatment (Days 15-29) was ineffective. In HUVECs, liraglutide treatment dose-dependently stimulated NO production, which was dependent on GLP-1R, cAMP, cAMP-dependent protein kinase, AMP-activated protein kinase (AMPK), and NOS. Subsequently, we investigated the role of liver kinase B (LKB)-1 in this process. Liraglutide increased the phosphorylation of LKB-1, and siRNA-induced LKB-1 knockdown abolished liraglutide-stimulated NO production. In severe hyperglycemic db/db mice, liraglutide treatment also suppressed neointimal hyperplasia, which was accompanied by reductions in vascular cell proliferation and density. Furthermore, liraglutide treatment suppressed hyperglycemia-enhanced vascular inflammation 7 days after arterial injury. We demonstrate that endothelial cells are targets of liraglutide, and suppress restenosis via endothelial NO. Furthermore, the protective effects are maintained in severe hyperglycemia. Our findings provide an evidence base for a future clinical trial to determine whether treatment with GL