Kazunobu Ishikawa Pages 2489 - 2497 ( 9 )
Heme oxygenase (HO), an enzyme essential for heme degradation, shows anti-oxidative and anti-inflammatory properties via the production of bile pigments, carbon monoxide (CO) and ferritin induction under various pathophysiological conditions. A number of recent studies have shown biological effects of HO reaction in cardiovascular disorders. An inducible form of HO, HO-1, is induced by a variety of stresses such as oxidized lipoproteins, cytokines, hemodynamic changes, angiotensin II and nitric oxide (NO) in vascular wall. HO-1 induction seems to function as an adaptive response against these injurious stimuli. HO-1 induction in artery wall scavenges reactive oxygen species, which leads to the attenuation of monocyte adhesion and chemotaxis. HO-1 induction also reduces lipid peroxidation in plasma and artery wall. These properties of HO-1 suggest anti-atherogenic roles of this enzyme. In this review, roles of endothelial HO-1 expression and bilirubin in atherogenesis are also discussed. HO-1 also seems to play a significant role in restenosis after angioplasty, which is a major clinical problem associated with atherosclerosis. Recent progress in human HO-1 genetics supports these experimental results. This review aims to reaffirm current problems in the biological aspects of HO and suggest future research direction and clinical application.
heme oxygenase,carbon monoxide,bilirubin,ferritin,oxidative stress,atherosclerosis,restenosis
First Department of Internal Medicine, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima-city,Fukushima, 960-1295, Japan.