HMOX1 and Huntington disease: Indeed, there is an increasing support that HO-1 plays a crucial protective role in the central nervous system (CNS), primarily in astrocytes and microglia/macrophages, particularly during aging and in several disease states where oxidative stress is implicated, including Alzheimer’s disease (AD), Parkinson’s disease (PD) and Huntington’s disease (HD; Calabrese et al., 2004).