HMOX2 and cerebrovascular disorder: The role of HO-2 in cerebrovascular diseases is still unclear, because some evidence suggests that the enzyme is neuroprotective, whereas other studies support the opposite hypothesis (Doré et al., 1999a; Doré et al., 2000; Goto et al., 2003; Qu et al., 2007; Chen-Roetling et al., 2014; Goto et al., 2018).