title: Bilirubin exerts pro-angiogenic property through Akt-eNOS-dependent pathway.
abstract: Low serum bilirubin levels are associated with the risk of cardiovascular diseases including peripheral artery disease. Bilirubin is known to exert its property such as antioxidant effect or the enhancement of flow-mediated vasodilation, however, bilirubin action on angiogenesis remains unclear. To investigate the molecular mechanism of bilirubin on angiogenic effect, we first employed C57BL/6J mice with unilateral hindlimb ischemia surgery and divided the mice into two groups (vehicle-treated group and bilirubin-treated group). The analysis of laser speckle blood flow demonstrated the enhancement of blood flow recovery in response to ischemia of mice with bilirubin treatment. The density of capillaries was significantly higher in ischemic-adductor muscles of bilirubin-treated mice. The phosphorylated levels of endothelial nitric oxide synthase (eNOS) and Akt were increased in ischemic skeletal muscles of mice with bilirubin treatment compared with vehicle treatment. In in vitro experiments by using human aortic endothelial cells, bilirubin augmented eNOS and Akt phosphorylation, cell proliferation, cell migration and tube formation. These bilirubin actions on endothelial cell activation were inhibited by LY294002, a phosphatidylinositol 3-kinase inhibitor. In conclusion, bilirubin promotes angiogenesis through endothelial cells activation via Akt-eNOS-dependent manner.
authors.affiliation: Department of Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Ikeda
authors.affiliation: Department of Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.|Department of Pharmacy, Tokushima University Hospital, Tokushima, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hamano
authors.affiliation: Department of Medical Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Akiho
authors.initials: A
authors.lastname: Satoh
authors.affiliation: Department of Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.|Department of Pharmacy, Tokushima University Hospital, Tokushima, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Horinouchi
authors.affiliation: Department of Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Izawa-Ishizawa
authors.affiliation: Department of Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kihira
authors.affiliation: Department of Pharmacy, Tokushima University Hospital, Tokushima, Japan.|Department of Clinical Pharmacy, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ishizawa
authors.affiliation: Department of hematology, endocrinology and metabolism, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Aihara
authors.affiliation: Department of Medical Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsuchiya
authors.affiliation: Department of Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tamaki
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology* / Q000627:therapeutic use; D001663:Bilirubin / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects*; D006614:Hindlimb / Q000098:blood supply; D006801:Humans; D007511:Ischemia / Q000188:drug therapy* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000098:blood supply; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D000975:Antioxidants; D013481:Superoxides; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D001663:Bilirubin