HO-2 has been found to be closely associated with sGC, ALA synthase, cytochrome P450 reductase and NOS in the brain (Wu and Wang, 2005). levels in tissue, e.g., kernicterus. Care must be used to ensure that when these compounds are used as therapeutic agents their deleterious effects are minimized or avoided. On balance, however, the strategies to target heme oxygenase-1 as described in this review offer promising therapeutic approaches to clinicians for the effective management of hypertension and renal function. The approaches detailed may prove to be seminal in the development of a new therapeutic strategy to treat hypertension. strong class=”kwd-title” Keywords: Heme oxygenase, Hypertension, Carbon monoxide, Bilirubin, Adiponectin 1. Introduction Heme oxygenase (HO), comprising HO-1 and HO-2, functions as Ibuprofen (Advil) the rate-limiting enzyme in the degradation of heme, a process that leads to formation of equimolar amounts of the bile pigment biliverdin, free iron and carbon monoxide (CO). Biliverdin formed in this reaction is rapidly converted to bilirubin. Heme oxygenase has been reported to be present in all tissues and is located in microsomes (Abraham and Kappas, 2008). Recently HO-1 and HO-2 have been shown to be also present in mitochondria (Di Noia et al., 2006; Turkseven et al., 2007). It is now apparent that HO-2 is constitutively expressed, whereas HO-1 is inducible by Ibuprofen (Advil) a large number of structurally unrelated pharmacological and other agents as well as by a variety of circumstances, that include heat shock and both cellular and oxidant stress. The HO system provides both antioxidant and anti-apoptotic properties due to its byproducts, bilirubin/biliverdin and CO, respectively (Abraham and Kappas, 2008) (Fig. 1). HO-1 is induced by oxidant stress and plays a crucial role in protection against oxidative insult in diabetes and cardiovascular diseases (Abraham and Kappas, 2008). Open in a separate window Fig. EPHB4 1 Functional consequences of the three heme degradation products, biliverdin, iron, and carbon monoxide (CO). Biliverdin is converted to bilirubin in a stereospecific manner by the cytosolic enzyme, biliverdin reductase. Both CO and bilirubin are bioactive molecules while the iron generated by heme degradation is immediately sequestered by associated increases in ferritin. Heme oxygenase (HO), the rate-limiting enzyme in heme degradation exists Ibuprofen (Advil) in two isoforms, HO-1 (inducible) and HO-2 (constitutive). A spectrum of drugs have been used to up-regulate HO-1 expression and HO activity. Stannous chloride (SnCl2) has been reported to lower blood pressure in spontaneously hypertensive rats (Sacerdoti et al., 1989). Metalloporphyrins, such as heme, heme arginate, and CoPP, are also commonly used drugs to induce HO-1 expression and HO activity and have been used to normalize blood pressure in animals and humans (Kordac et al., 1989; Levere et al., 1990; Abraham and Kappas, 2008). However, in discovering the ideal pharmacological drug, one must consider the dose and time of HO-1 induction. Therefore, most of the pharmacological inducers of HO-1, such as hemin and heavy metals, used in experimental studies may show cellular and tissue toxicity if used at high concentrations. Thus, the adverse and long-term effects of increased HO-1 expression and its effect Ibuprofen (Advil) on the heme synthesis pathway must be elucidated before clinical application. Ibuprofen (Advil) Aspirin is known to reduce the incidence of thrombotic occlusive events, such as myocardial infarction and stroke. Aspirin increased HO-1 protein levels and HO activity in a dose-dependent manner in cultured endothelial cells derived from human umbilical vein. Pretreatment of cells with aspirin or bilirubin protected endothelial cells from H2O2-mediated toxicity (Abraham and Kappas, 2008). Another type of drug, statins, the widely used lipid-lowering agents, substantially decrease cardiovascular morbidity and mortality in patients with and without coronary disease. Simvastatin and lovastatin increase HO-1 mRNA levels in cultured endothelial cells derived from human umbilical vein (Abraham and Kappas, 2008). Recently, we reported that L-4F and D-4F mimetic peptides increased levels of aortic HO-1 protein, HO activity, and extracellular superoxide dismutase while decreasing superoxide levels (Abraham and Kappas, 2008; Peterson et al., 2007). Probucol, an antioxidant drug, reduces the risk of restenosis. The protective effect of probucol depends not only on its ability to inhibit lipid oxidation but also on its ability to induce HO-1. Treatment with paclitaxel, possessing antiproliferative effects on vascular smooth muscle cells, resulted in a marked time- and dose-dependent induction of HO-1 mRNA, followed by corresponding increases in HO-1 protein and HO activity (Choi et al., 2004). It has been suggested that HO-1, induced by rapamycin in VSMCs, shows an antiproliferative effect, resulting in the reduction of the restenosis rate (Abraham and Kappas, 2008). Resveratrol, an important component in certain varieties of.