HMOX1 and inflammatory response: The important role of HO enzymes in this capacity as well as the potential targeting of vascular HO for therapeutics is reviewed by E. Marcantoni et al. The importance of vascular HO-1 in the suppression of vascular inflammation is demonstrated in studies by K. Ishikawa et al. who show that HO-1 knockout mice exhibit enhanced vascular inflammation, atherosclerotic lesions, and increased oxidation of HDL.