Induction of heme oxygenase-1 suppresses venular leukocyte adhesion elicited by oxidative stress: Role of bilirubin generated by the enzyme

Shinobu Hayashi, Rina Takamiya, Tokio Yamaguchi, Kenji Matsumoto, Shinichiro J. Tojo, Takuya Tamatani, Masaki Kitajima, Nobuya Makino, Yuzuru Ishimura, Makoto Suematsu

Research output: Contribution to journalArticlepeer-review

334 Citations (Scopus)


This study aimed to examine whether an elevated activity of heme oxygenase (HO)-1 in the tissue attenuates endothelial cell-leukocyte interactions microvessels in vivo. When rats were pretreated with an intraperitoneal injection of hemin, an HO-1 inducer, mesenteric tissues, including their microvessels, displayed a marked induction of HO-1 concurrent with an increase in plasma concentrations of bilirubin-IXα, the product of HO-catalyzed degradation of protoheme IX. In these rats, oxidative stress such as superfusion with H2O2 and ischemia-reperfusion of the tissues neither induced rolling nor exhibited adherent responses of leukocytes in venules. In contrast, the oxidative stresses evoked marked rolling and adhesion of leukocytes in the control rats without HO-1 induction. The HO-1 induction also downregulated leukocyte adhesion elicited by other pro-oxidant stimuli such as N(ω)-nitro-L-arginine methyl ester. The decreases in the oxidant-elicited leukocyte adhesive responses under HO-1-inducing conditions were restored by perfusion with zinc protoporphyrin-IX, an HO inhibitor, but not with copper protoporphyrin-IX, which did not inhibit the enzyme. Furthermore, the effects of zinc protoporphyrin-IX were repressed by superfusion with bilirubin or biliverdin at the micromolar level, but not by the same concentration of carbon monoxide, another product of HO. These results indicate that induction of the HO-1 activity serves as a potential stratagem to prevent oxidant-induced microvascular leukocyte adhesion through the action of bilirubin, a product of HO reaction.

Original languageEnglish
Pages (from-to)663-671
Number of pages9
JournalCirculation research
Issue number8
Publication statusPublished - 1999 Oct 15
Externally publishedYes


  • Bilirubin
  • Carbon monoxide
  • Endothelial cell
  • Heme oxygenase
  • Oxidative stress

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine


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