title: Recombinant human thrombomodulin suppresses experimental abdominal aortic aneurysms induced by calcium chloride in mice.
abstract: OBJECTIVE
  To investigate whether recombinant thrombomodulin containing all the extracellular domains (rTMD123) has therapeutic potential against aneurysm development.
  
  
  BACKGROUND
  The pathogenesis of abdominal aortic aneurysm (AAA) is characterized by chronic inflammation and proteolytic degradation of extracellular matrix. Thrombomodulin, a transmembrane glycoprotein, exerts anti-inflammatory activities such as inhibition of cytokine production and sequestration of proinflammatory high-mobility group box 1 (HMGB1) to prevent it from engaging the receptor for advanced glycation end product (RAGE) that may sustain inflammation and tissue damage.
  
  
  METHODS
  The in vivo effects of treatment and posttreatment with rTMD123 on aortic dilatation were measured using the CaCl2-induced AAA model in mice.
  
  
  RESULTS
  Characterization of the CaCl2-induced model revealed that HMGB1 and RAGE, both localized mainly to macrophages, were persistently upregulated during a 28-day period of AAA development. In vitro, rTMD123-HMGB1 interaction prevented HMGB1 binding to macrophages, thereby prohibiting activation of HMGB1-RAGE signaling in macrophages. In vivo, short-term treatment with rTMD123 upon AAA induction suppressed the levels of proinflammatory cytokines, HMGB1, and RAGE in the aortic tissue; reduced the infiltrating macrophage number; and finally attenuated matrix metalloproteinase production, extracellular matrix destruction, and AAA formation without disturbing vascular calcification. Consistently, posttreatment with rTMD123 seven days after AAA induction alleviated vascular inflammation and retarded AAA progression.
  
  
  CONCLUSIONS
  These data suggest that rTMD123 confers protection against AAA development. The mechanism of action may be associated with reduction of proinflammatory mediators, blockade of macrophage recruitment, and suppression of HMGB1-RAGE signaling involved in aneurysm formation and downstream macrophage activation.
authors.affiliation: *Institute of Clinical Medicine †Cardiovascular Research Center ‡Departments of Surgery; and §Biochemistry and Molecular Biology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chao-Han
authors.initials: CH
authors.lastname: Lai
authors.forename: Guey-Yueh
authors.initials: GY
authors.lastname: Shi
authors.forename: Fang-Tzu
authors.initials: FT
authors.lastname: Lee
authors.forename: Cheng-Hsiang
authors.initials: CH
authors.lastname: Kuo
authors.forename: Tsung-Lin
authors.initials: TL
authors.lastname: Cheng
authors.forename: Bi-Ing
authors.initials: BI
authors.lastname: Chang
authors.forename: Chih-Yuan
authors.initials: CY
authors.lastname: Ma
authors.forename: Fu-Chih
authors.initials: FC
authors.lastname: Hsu
authors.forename: Yu-Jen
authors.initials: YJ
authors.lastname: Yang
authors.forename: Hua-Lin
authors.initials: HL
authors.lastname: Wu
mesh_terms: D000818:Animals; D017544:Aortic Aneurysm, Abdominal / Q000139:chemically induced / Q000517:prevention & control*; D002122:Calcium Chloride / Q000008:administration & dosage; D051379:Mice; D008810:Mice, Inbred C57BL; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000502:physiology; D011994:Recombinant Proteins / Q000627:therapeutic use; D018180:Thrombomodulin / Q000627:therapeutic use*
chemical_list: D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D011994:Recombinant Proteins; C546931:THBD protein, human; D018180:Thrombomodulin; D002122:Calcium Chloride