Hemopexin (HPX) is a plasma protein with the strongest binding capacity to heme and widely involved in modulation of a variety of physiological and pathological processes. The main physiological function of HPX is to bind and transport free toxic heme. Recent studies indicate that HPX also plays roles of anti-oxidant, anti-apoptosis, immune regulation and organic protection. In addition, HPX participates in regulation of cell differentiation and extracellular matrix reconstruction. In recent years, a great deal of progress has been made in studies of the mechanisms of HPX protective effects and on possible clinical application. In the past few years, especially, a number of proteomic studies have demonstrated that HPX could be served as positive molecular biomarkers for cancers of lung, liver, kidney, colon, and uterine myoma as well as osteoarthritis. In this review, recent progress in the biochemical characteristics and function of HPX and its possible clinical applications are summarized.
Heme ; Heme Oxygenase (Decyclizing) ; Hemopexin ; chemistry ; metabolism ; Humans

Heme oxygenase (HO)-1 is an inducible enzyme that catalyzes the first and rate-limiting step in the oxidative degradation of free heme into ferrous iron, carbon monoxide (CO), and biliverdin (BV), the latter being subsequently converted into bilirubin (BR). HO-1, once expressed during inflammation, forms high concentrations of its enzymatic by-products that can influence various biological events, and this expression is proven to be associated with the resolution of inflammation. The degradation of heme by HO-1 itself, the signaling actions of CO, the antioxidant properties of BV/BR, and the sequestration of ferrous iron by ferritin all concertedly contribute to the anti-inflammatory effects of HO-1. This review focuses on the anti-inflammatory mechanisms of HO-1 actions and its roles in inflammatory diseases.
Bilirubin ; Biliverdine ; Carbon Monoxide ; Ferritins ; Heme ; Heme Oxygenase (Decyclizing) ; Heme Oxygenase-1 ; Inflammation ; Iron

Heme oxygenase (HO)-1 is an inducible enzyme that catalyzes the first and rate-limiting step in the oxidative degradation of free heme into ferrous iron, carbon monoxide (CO), and biliverdin (BV), the latter being subsequently converted into bilirubin (BR). HO-1, once expressed during inflammation, forms high concentrations of its enzymatic by-products that can influence various biological events, and this expression is proven to be associated with the resolution of inflammation. The degradation of heme by HO-1 itself, the signaling actions of CO, the antioxidant properties of BV/BR, and the sequestration of ferrous iron by ferritin all concertedly contribute to the anti-inflammatory effects of HO-1. This review focuses on the anti-inflammatory mechanisms of HO-1 actions and its roles in inflammatory diseases.
Bilirubin ; Biliverdine ; Carbon Monoxide ; Ferritins ; Heme ; Heme Oxygenase (Decyclizing) ; Heme Oxygenase-1 ; Inflammation ; Iron

PURPOSE: The inducible isoform of heme oxygenase(HO), HO-1, responds to hypoxia. HO-1 regulates vascular smooth muscle tone through carbon monoxide production. To investigate the possible role of HO-1 in low-flow priapism, we examined the expression and activity of HO-1 in artificially induced veno-occlusive priapism in rat. MATERIALS AND METHODS: Fourteen male Sprague Dawley rats were divided into 2 groups with 7 rats each. In the first group, low-flow priapism was induced using a vacuum-constriction device and a constriction rubber band; in the second group, low-flow priapism was induced using papaverine. We measured the expression level and activity of HO-1 in penile tissues after time periods of 0(control), 2, 3, 4, 8, 12, 24, and 48 hours. At the same time, the expression levels of i-NOS, e-NOS, and beta-actin(control) in penile tissues were also measured. RESULTS: In both groups, expression of HO-1 and HO-1 enzyme activities in penile tissue significantly increased in a time dependent fashion(p<0.01). However, there was no difference in the expression of i-NOS and e-NOS in both groups at any time period. CONCLUSIONS: HO-1 was induced over time in rats with artificially induced veno-occlusive priapism. Induction of HO-1 may play a protective role against hypoxic injury, but may also play an important role in the vicious cycle observed for low flow priapism. Increasing induction of HO-1 against hypoxic injury in a prolonged erectile state promotes sustained dilatation of corporal smooth muscle, and this may aggravate low-flow priapism.
Animals ; Anoxia ; Carbon Monoxide ; Constriction ; Dilatation ; Heme Oxygenase (Decyclizing) ; Heme Oxygenase-1* ; Heme* ; Humans ; Male ; Muscle, Smooth ; Muscle, Smooth, Vascular ; Papaverine ; Priapism* ; Rats* ; Rats, Sprague-Dawley ; Rubber

Carcinogenesis ; Cell Transformation, Neoplastic ; Heme Oxygenase-1 ; Humans

The Porphyria are a group of inherited and acquired disorders characterized by partial defects in the heme biosynthetic pathway. Among the hepatic forms, acute intermittent porphyria(AIP) is the most severe and common type in western hemisphere. Though its association with pregnancy is rare, it presents the obstetrician with challenging problems in diagnosis and management and it is probable that pregnancy had some deleterious effect in acute porphyria. The authors present a cae of AIP in pregnancy with a review of literature.
Biosynthetic Pathways ; Diagnosis ; Heme ; Porphyria, Acute Intermittent* ; Porphyrias ; Pregnancy*

Catalases are well studied enzymes that play critical roles in protecting cells against the toxic effects of hydrogen peroxide. The ubiquity of the enzyme and the availability of substrates made heme catalases the focus of many biochemical and molecular biology studies over 100 years. In human, this has been implicated in various physiological and pathological conditions. Advancement in proteomics revealed many of novel and previously unknown features of this mysterious enzyme, but some functional aspects are yet to be explained. Along with discussion on future research area, this mini-review compile the information available on the structure, function and mechanism of action of human catalase.
Catalase ; chemistry ; metabolism ; physiology ; Heme ; chemistry ; Humans ; Hydrogen Peroxide ; metabolism

PURPOSE: To evaluate the effects of oxidative stress and antioxidantson heme oxygenase-1 (HO-1) in cultured human retinal pigment epithelial (RPE) cells. METHODS: Cultured RPE cells were challenged with different concentrations of hydrogen peroxide (H2O2), and the HO-1 mRNA level was determined by RT-PCR after 24 hours and 48 hours of incubation independently. Additionally, the HO-1 mRNA level was measured after preincubating RPE cells with N-acetylcystein (NAC) as the antioxidant for 30 minutes and then challenging the cells with H2O2. RESULTS: The expression of the HO-1 mRNA level increased after H2O2 exposure, and this level was proportional to the increased H2O2 concentration (p<0.05). Expression of the HO-1 mRNA level decreased when the RPE cells were preincubated with NAC (p<0.05). CONCLUSIONS: In human RPE cells, the HO-1 level increased in proportion to the degree of oxidative stress and decreased with exposure to antioxidants. Expression of HO-1 may be helpful in preventing retinal disease, which occurs due to oxidative stresses such as age-related macular degeneration.
Antioxidants ; Heme ; Heme Oxygenase-1 ; Humans ; Hydrogen Peroxide ; Macular Degeneration ; Oxidative Stress ; Retinal Diseases ; Retinal Pigment Epithelium ; Retinaldehyde ; RNA, Messenger

PURPOSE: To evaluate the effects of oxidative stress and antioxidantson heme oxygenase-1 (HO-1) in cultured human retinal pigment epithelial (RPE) cells. METHODS: Cultured RPE cells were challenged with different concentrations of hydrogen peroxide (H2O2), and the HO-1 mRNA level was determined by RT-PCR after 24 hours and 48 hours of incubation independently. Additionally, the HO-1 mRNA level was measured after preincubating RPE cells with N-acetylcystein (NAC) as the antioxidant for 30 minutes and then challenging the cells with H2O2. RESULTS: The expression of the HO-1 mRNA level increased after H2O2 exposure, and this level was proportional to the increased H2O2 concentration (p<0.05). Expression of the HO-1 mRNA level decreased when the RPE cells were preincubated with NAC (p<0.05). CONCLUSIONS: In human RPE cells, the HO-1 level increased in proportion to the degree of oxidative stress and decreased with exposure to antioxidants. Expression of HO-1 may be helpful in preventing retinal disease, which occurs due to oxidative stresses such as age-related macular degeneration.
Antioxidants ; Heme ; Heme Oxygenase-1 ; Humans ; Hydrogen Peroxide ; Macular Degeneration ; Oxidative Stress ; Retinal Diseases ; Retinal Pigment Epithelium ; Retinaldehyde ; RNA, Messenger

OBJECTIVETo investigate the location of heme oxygenase (HO) enzyme in the human testis, and explore the correlation of the expression of HO enzyme with azoospermia by analyzing its different expression levels in the testes of nonobstructive azoospermia, obstructive azoospermia and normal men.

METHODSWe detected the location of the cells expressing HO enzyme in the human testis tissue using immunohistochemistry, determined the mRNA and protein expression levels of HO-1 and HO-2 in the testes of azoospermia patients and normal healthy men by RT-fluorescence quantitative PCR (RT-FQ-PCR) and Western blot, and explored the correlation of HO expressions with the pathogenesis of azoospermia.

RESULTSHO-1 enzyme was expressed mainly in the Sertoli cells and HO-2 enzyme chiefly in the germ cells of the testis tissue. RT-FQ-PCR showed that the expression of HO-1 in the testis tissue was significantly lower in the nonobstructive azoospermia than in the normal and obstructive azoospermia groups (P < 0.05), with no significant difference between the latter two. Western blot revealed no obvious difference between the expression level of HO-1 protein and that of HO-1 mRNA. There were no differences in the expression level of HO-2 protein among the three groups.

CONCLUSIONThe expression level of HO enzyme is significantly decreased in the testis tissue of nonobstructive azoospermia patients, and the expression of HO-1 protein is consistent with that of HO-1 mRNA. As HO-1 protects the testis tissue against various stress injuries through its antioxidant, anti-inflammatory and anti-apoptotic effects, its decreased expression level may be correlated with spermatogenic dysfunction, and therefore considered as a possible mechanism of nonobstructive azoospermia.

Azoospermia ; enzymology ; metabolism ; Case-Control Studies ; Heme Oxygenase (Decyclizing) ; metabolism ; Heme Oxygenase-1 ; metabolism ; Humans ; Male ; Spermatogenesis ; Testis ; enzymology ; metabolism