HMOX1 and inflammatory bowel disease: Given that the heme metabolic process was proven to be the trigger and target of the artemisinin family [23], and that HO-1 can regulate Th/Treg disorders (which comprise the pathogenic basis of IBD), we hypothesized that DHA would have protective effects on IBD, and that the underlying mechanism would comprise Th/Treg modulation through the regulation of HO-1.