HMOX1 and atherosclerosis: Halit et al. reported that patients with acute myocardial infarction with impaired blood flow had higher bilirubin levels than the group with normal blood flow, suggesting that the more severe the degree of atherosclerosis and the higher the post-infarction HO-1 enzyme activity, the more marked the increase in bilirubin levels, and the degree of increase was related to the severity of the lesion [29].