That is, HO-2 is the physiological regulator of cellular functions, while HO-1 has a cytoprotective role, regulating tissue responses to injury in pathophysiological states (Kim et al., 2011); therefore, this review will be mainly focused on vascular and macrophage HO-1 and its possible role in hypertension-associated vascular alterations. The gene discussed is HMOX1; the disease is Hypertension.