Heme oxygenase-1 improves the survival of ischemic skin flaps

Heat shock protein 32 (Hsp32), also known as heme oxygenase-1 (HO-1), is an enzyme that exists in microsomes. HO-1 can be induced by a variety of stimuli, including heavy metals, heat shock, inflammatory stimuli, heme and its derivatives, stress, hypoxia, and biological hormones. HO-1 is the rate-limiting enzyme of heme catabolism, which splits heme into biliverdin, carbon monoxide (CO) and iron. The metabolites of HO-1 have anti-inflammatory and anti-oxidant effects, and provide protection to the cardiovascular system and transplanted organs. This review summarizes the biological characteristics of HO-1 and the functional significance of its products, and specifically elaborates on its protective effect on skin flaps. HO-1 improves the survival rate of ischemic skin flaps through anti-inflammatory, anti-oxidant and vasodilatory effects of enzymatic reaction products. In particular, this review focuses on the role of carbon monoxide (CO), one of the primary metabolites of HO-1, in flap survival and discusses the feasibility and existing challenges of HO-1 in flap surgery.