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Taurine Normalizes Blood Levels and Urinary Loss of Selenium, Chromium, and Manganese in Rats Chronically Consuming Alcohol. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009. [DOI: 10.1007/978-0-387-75681-3_42] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Speckmann B, Walter PL, Alili L, Reinehr R, Sies H, Klotz LO, Steinbrenner H. Selenoprotein P expression is controlled through interaction of the coactivator PGC-1alpha with FoxO1a and hepatocyte nuclear factor 4alpha transcription factors. Hepatology 2008; 48:1998-2006. [PMID: 18972406 DOI: 10.1002/hep.22526] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Selenoprotein P (SeP), the major selenoprotein in plasma, is produced mainly by the liver, although SeP expression is detected in many organs. Recently, we reported stimulation of SeP promoter activity by the forkhead box transcription factor FoxO1a in hepatoma cells and its attenuation by insulin. Here, we demonstrate that this translates into fine-tuning of SeP production and secretion by insulin. Overexpression of peroxisomal proliferator activated receptor-gamma coactivator 1alpha (PGC-1alpha) enhanced the stimulatory effect of FoxO1a on SeP promoter activity. We identified a novel functional binding site for hepatocyte nuclear factor (HNF)-4alpha, termed hepatocyte nuclear factor binding element 1, in the human SeP promoter directly upstream of the FoxO-responsive element daf16-binding element 2 (DBE2). Point mutations in hepatocyte nuclear factor binding element 1 alone or together with DBE2 decreased basal activity and responsiveness of the SeP promoter to PGC-1alpha. Moreover, the PGC-1alpha-inducing glucocorticoid dexamethasone strongly enhanced SeP messenger RNA levels and protein secretion in cultured rat hepatocytes, whereas insulin suppressed the stimulation of both PGC-1alpha and SeP caused by dexamethasone treatment. In a brain-derived neuroblastoma cell line with low basal SeP expression, SeP transcription was stimulated by PGC-1alpha together with FoxO1a, and overexpression of HNF-4alpha potentiated this effect. CONCLUSION High-level expression of SeP in liver is ensured by concerted action of the coactivator PGC-1alpha and the transcription factors FoxO1a and HNF-4alpha. Hence, the production of SeP is regulated similarly to that of the gluconeogenic enzyme glucose-6-phosphatase. As hepatic SeP production is crucial for selenium distribution throughout the body, the present study establishes PGC-1alpha as a key regulator of selenium homeostasis.
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Affiliation(s)
- Bodo Speckmann
- Institute for Biochemistry and Molecular Biology I, Hepatology and Infectiology, Heinrich-Heine-University, Düsseldorf, Germany
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Abstract
Following the publication of the landmark trial of Clark et al. in 1996 that appeared to show that Se could reduce the risk of cancer, awareness of the importance of Se to human health has markedly increased. As a result, there is now much more aggressive marketing of Se supplements and functional foods, even in situations where additional consumption of Se is inappropriate. The present review addresses how Se gets into the food chain, the wide variability in Se content of foods and the very different levels of intake between countries and regions. Though it is clear that there are adverse consequences for health of both deficient and excessive intake, health effects at intermediate levels of intake are less certain. Thus it is difficult to define optimal intake which depends on a large number of factors, such as which functions of Se are most relevant to a particular disease state, which species of Se is most prominent in the Se source, which health condition is being considered, the adequacy or otherwise of intake of other nutrients, the presence of additional stressors, and lastly whether the ability to make selenoproteins may be compromised. These complexities need to be understood, particularly by policy makers, in order to make informed judgments. Potential solutions for increasing Se intake, where required, include agronomic biofortification and genetic biofortification or, for individuals, increased intake of naturally Se-rich foods, functional foods or supplements. The difficulties of balancing the risks and benefits in relation to Se intake are highlighted.
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Bosschaerts T, Guilliams M, Noel W, Hérin M, Burk RF, Hill KE, Brys L, Raes G, Ghassabeh GH, De Baetselier P, Beschin A. Alternatively activated myeloid cells limit pathogenicity associated with African trypanosomiasis through the IL-10 inducible gene selenoprotein P. THE JOURNAL OF IMMUNOLOGY 2008; 180:6168-75. [PMID: 18424738 DOI: 10.4049/jimmunol.180.9.6168] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Uncontrolled inflammation is a major cause of tissue injury/pathogenicity often resulting in death of a host infected with African trypanosomes. Thus, comparing the immune response in hosts that develop different degrees of disease severity represents a promising approach to discover processes contributing to trypanosomiasis control. It is known that limitation of pathogenicity requires a transition in the course of infection, from an IFN-gamma-dependent response resulting in the development of classically activated myeloid cells (M1), to a counterbalancing IL-10-dependent response associated with alternatively activated myeloid cells (M2). Herein, mechanisms and downstream effectors by which M2 contribute to lower the pathogenicity and the associated susceptibility to African trypanosomiasis have been explored. Gene expression analysis in IL-10 knockout and wild-type mice, that are susceptible and relatively resistant to Trypanosoma congolense infection, respectively, revealed a number of IL-10-inducible genes expressed by M2, including Sepp1 coding for selenoprotein P. Functional analyses confirm that selenoprotein P contributes to limit disease severity through anti-oxidant activity. Indeed, Sepp1 knockout mice, but not Sepp1(Delta)(240-361) mice retaining the anti-oxidant motif but lacking the selenium transporter domain of selenoprotein P, exhibited increased tissue injury that associated with increased production of reactive oxygen species and increased apoptosis in the liver immune cells, reduced parasite clearance capacity of myeloid cells, and decreased survival. These data validate M2-associated molecules as functioning in reducing the impact of parasite infection on the host.
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Affiliation(s)
- Tom Bosschaerts
- Department of Molecular and Cellular Interactions, Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, Belgium
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55
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Selenium and cancer: biomarkers of selenium status and molecular action of selenium supplements. Eur J Nutr 2008; 47 Suppl 2:29-50. [DOI: 10.1007/s00394-008-2005-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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56
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Gazzana G, Borlak J. Mapping of the serum proteome of hepatocellular carcinoma induced by targeted overexpression of epidermal growth factor to liver cells of transgenic mice. J Proteome Res 2008; 7:928-37. [PMID: 18198842 DOI: 10.1021/pr070462c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Epidermal growth factor (EGF) is an important mitogen for hepatocytes. Its targeted overexpression induced hepatocellular carcinomas (HCC), as recently reported by us (Borlak et al. 2005). Early detection of disease is essential for successful therapy and overall survival. Here we describe our efforts in identifying serum biomarkers of liver cancer in a transgenic disease model that mimics effectively the consequence of exaggerated EGF signaling. We report a reference 2-DE map of mouse serum proteins. About 180 proteins were detected per gel and 130 proteins were identified by 2-DE-MALDI-MS analysis. We compared serum proteins of healthy nontransgenic and HCC tumor-bearing mice and identified 25 regulated proteins, of which n = 7 reached statistical significance ( p < 0.05). Furthermore, we identified several fragments of fibrinogens and of the alpha-2-macroglobulin to be disease-associated. We also found immunoglobulins to be repressed or absent in serum samples of tumor-bearing mice, and this included, among others, the Ig K and L class. In contrast, amyloid component P and apolipoprotein M were highly significantly increased by 10- and 8-fold, respectively, in serum samples of HCC mice. Overall, our findings provide a rationale for further clinical evaluation of the herein identified biomarker candidates.
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Affiliation(s)
- Giuseppe Gazzana
- Department of Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany
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57
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Kabuyama Y, Oshima K, Kitamura T, Homma M, Yamaki J, Munakata M, Homma Y. Involvement of selenoprotein P in the regulation of redox balance and myofibroblast viability in idiopathic pulmonary fibrosis. Genes Cells 2007; 12:1235-44. [DOI: 10.1111/j.1365-2443.2007.01127.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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58
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Kim H, Park H, Kwon K. J Pharmacopuncture 2007; 10:121-135. [DOI: 10.3831/kpi.2007.10.1.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Burk RF, Norsworthy BK, Hill KE, Motley AK, Byrne DW. Effects of chemical form of selenium on plasma biomarkers in a high-dose human supplementation trial. Cancer Epidemiol Biomarkers Prev 2006; 15:804-10. [PMID: 16614127 DOI: 10.1158/1055-9965.epi-05-0950] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Intervention trials with different forms of selenium are under way to assess the effects of selenium supplements on the incidence of cancer and other diseases. Plasma selenium biomarkers respond to selenium administration and might be useful for assessing compliance and safety in these trials. The present study characterized the effects of selenium supplementation on plasma selenium biomarkers and urinary selenium excretion in selenium-replete subjects. Moderate (approximately 200 microg/d) to large (approximately 600 microg/d) selenium supplements in the forms sodium selenite, high-selenium yeast (yeast), and l-selenomethionine (selenomethionine) were administered. Subjects were randomized into 10 groups (placebo and three dose levels of each form of selenium). Plasma biomarkers (selenium concentration, selenoprotein P concentration, and glutathione peroxidase activity) were determined before supplementation and every 4 weeks for 16 weeks. Urinary selenium excretion was determined at 16 weeks. Supplementation with selenomethionine and yeast raised the plasma selenium concentration in a dose-dependent manner. Selenite did not. The increased selenium concentration correlated with the amount of selenomethionine administered. Neither glutathione peroxidase activity nor selenoprotein P concentration responded to selenium supplementation. Urinary selenium excretion was greater after selenomethionine than after selenite, with excretion after yeast being intermediate and not significantly different from either of the other two. We conclude that plasma selenium concentration is useful in monitoring compliance and safety of selenium supplementation as selenomethionine but not as selenite. Plasma selenium seems to reflect the selenomethionine content of yeast but not the other yeast selenium forms. As judged by urinary selenium excretion, selenium in the form of selenomethionine is better absorbed than selenite.
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Affiliation(s)
- Raymond F Burk
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-0252, USA.
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Breedlove HA, Smith AM, Burk RF, Hill KE, Shapiro CL. Serum selenium measurements in women with early-stage breast cancer with and without chemotherapy-induced ovarian failure. Breast Cancer Res Treat 2006; 97:225-30. [PMID: 16791483 DOI: 10.1007/s10549-005-9012-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2005] [Indexed: 10/24/2022]
Abstract
Blood selenium has been shown to decline as breast cancer progresses and fluctuate with estrogen. The objective of this study was to determine the effect of estrogen depletion resulting from chemotherapy-induced ovarian failure on serum selenium and selenoproteins in stage I/II premenopausal breast cancer patients. Serum selenium, glutathione peroxidase (GPx) activity, and selenoprotein P (SelP) were measured and a dietary questionnaire was completed at baseline (before chemotherapy) and 6, 12, and 24 months after start of chemotherapy. Twelve months after the start of adjuvant chemotherapy 33 (75%) patients developed ovarian failure (OF) and 11 (25%) retained menstrual function (non-OF). Dietary selenium intake was 30-58% above the Recommended Dietary Allowance for both groups. By six months the mean estradiol (pg/ml) was lower in the OF group than in the non-OF group (32+/-5 versus 140+/-62 pg/ml, p=0.01) and this difference was maintained at 12 and 24 months. However, there was no differences in serum selenium, GPx activity, or SelP in the OF and non-OF groups at 6, 12, and 24 months. Selenium status in premenopausal breast cancer patients, as measured by serum selenium, GPx and SelP, was within the normal range before and following adjuvant chemotherapy, and was not affected by chemotherapy-induced ovarian failure.
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Affiliation(s)
- Hollie A Breedlove
- Department of Human Nutrition, The Ohio State University, Columbus, OH 43210, USA
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61
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Buchman AL, Iyer K, Fryer J. Parenteral nutrition-associated liver disease and the role for isolated intestine and intestine/liver transplantation. Hepatology 2006; 43:9-19. [PMID: 16374841 DOI: 10.1002/hep.20997] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Parenteral nutrition-associated liver disease (PNALD) is the most devastating complication of long-term parenteral nutrition therapy. Because its progression is typically insidious and its long-term consequences are generally underappreciated, PNALD is often recognized too late, when liver injury is irreversible. When end-stage liver disease (ESLD) develops in these patients, most potential interventions are futile and transplantation of both an intestine and a liver becomes the only viable option, despite the relatively poor outcomes associated with this combined procedure. Although likely multifactorial in origin, the etiology of PNALD is poorly understood. Early clinical intervention with a combination of nutritional, medical, hormonal, and surgical therapies can be effective in preventing liver disease progression. If these interventions fail, intestinal transplantation should be performed expeditiously before development of ESLD mandates simultaneous inclusion of a liver graft as well.
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Affiliation(s)
- Alan L Buchman
- Division of Gastroenterology, Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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62
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Abstract
OBJECTIVE In alcoholic liver disease (ALD), progression from initial steatosis, through hepatitis to cirrhosis is well described, resulting in 20,000 deaths in the UK annually. However, pathological mechanisms are not well understood and drug trials have led to conflicting results. It has been established that alcohol consumption increases hepatic free radical production and oxidant stress has been implicated in the disease process. MATERIAL AND METHODS Markers of lipid peroxidation, antioxidant status, hepatic fibrogenesis, inflammation and liver function were measured in blood and urine from 24 patients with established alcoholic cirrhosis and in 49 age- and sex-matched controls. RESULTS In the ALD group, lipid peroxidation markers 8-isoprostane and malondialdehyde were significantly increased (p<0.001), as was the ratio of oxidized to reduced glutathione (p=0.027). The antioxidants selenium, glutathione (whole blood and plasma) and vitamins A, C and E were all significantly decreased (p<0.001); median plasma glutathione levels were only 19% of control levels. Type III procollagen peptide (PIIINP), a serum marker of hepatic fibrogenesis, and C-reactive protein (CRP) were both increased (p<0.001). Urinary 8-isoprostane correlated positively with PIIINP, CRP and markers of cholestasis (alkaline phosphatase and bilirubin) and negatively with glutathione (whole blood), vitamins A and E and albumin. CONCLUSIONS Oxidant stress, as reflected in blood and urine by a wide range of pro- and antioxidant markers, is a significant feature of alcoholic cirrhosis, providing a mechanism by which alcohol intake may be linked to hepatic inflammation and fibrosis. Non-invasive markers could prove valuable in monitoring response to treatment during clinical trials.
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63
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Burk RF, Hill KE. Selenoprotein P: an extracellular protein with unique physical characteristics and a role in selenium homeostasis. Annu Rev Nutr 2005; 25:215-35. [PMID: 16011466 DOI: 10.1146/annurev.nutr.24.012003.132120] [Citation(s) in RCA: 387] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Selenoprotein P is an abundant extracellular glycoprotein that is rich in selenocysteine. It has two domains with respect to selenium content. The N-terminal domain of the rat protein contains one selenocysteine residue in a UxxC redox motif. This domain also has a pH-sensitive heparin-binding site and two histidine-rich amino acid stretches. The smaller C-terminal domain contains nine selenocysteine and ten cysteine residues. Four isoforms of selenoprotein P are present in rat plasma. They share the same N terminus and amino acid sequence. One isoform is full length and the three others terminate at the positions of the second, third, and seventh selenocysteine residues. Selenoprotein P turns over rapidly in rat plasma with the consequence that approximately 25% of the amount of whole-body selenium passes through it each day. Evidence supports functions of the protein in selenium homeostasis and oxidant defense. Selenoprotein P knockout mice have very low selenium concentrations in the brain, the testis, and the fetus, with severe pathophysiological consequences in each tissue. In addition, those mice waste moderate amounts of selenium in the urine. Selenoprotein P binds to endothelial cells in the rat, and plasma levels of the protein correlate with prevention of diquat-induced lipid peroxidation and hepatic endothelial cell injury. The mechanisms of these apparent functions remain speculative and much work on the mechanism of selenoprotein P function lies ahead. Measurement of selenoprotein P in human plasma has shown that it is depressed by selenium deficiency and by cirrhosis. Selenium supplementation of selenium-deficient human subjects showed that glutathione peroxidase activity was optimized before selenoprotein P concentration was optimized, indicating that plasma selenoprotein P is the better index of human selenium nutritional status.
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Affiliation(s)
- Raymond F Burk
- Division of Gastroenterology, Department of Medicine and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
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Pemberton PW, Aboutwerat A, Smith A, Burrows PC, McMahon RFT, Warnes TW. Oxidant stress in type I autoimmune hepatitis: the link between necroinflammation and fibrogenesis? Biochim Biophys Acta Mol Basis Dis 2004; 1689:182-9. [PMID: 15276644 DOI: 10.1016/j.bbadis.2004.01.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Accepted: 01/16/2004] [Indexed: 11/20/2022]
Abstract
Autoimmune hepatitis (AIH) is a chronic liver disease of unknown aetiology characterized by circulating autoantibodies, hyperglobulinaemia and interface hepatitis. The mechanisms of progression from initial autoimmune attack to fibrosis and cirrhosis are unclear but oxidant stress may be involved. Markers of lipid peroxidation, antioxidant status, hepatic fibrogenesis and liver function were measured in blood and urine in 35 controls and in 33 patients with type-1 AIH; histology was assessed in 18 patients. In AIH, markers of lipid peroxidation were significantly elevated (8-isoprostane in both plasma and urine P < 0.001; plasma malondialdehyde P = 0.017). Total antioxidant capacity in protein-free serum and total glutathione in both whole blood and plasma were significantly reduced (P = 0.007, P = 0.037, P < 0.001, respectively). The antioxidants selenium, vitamin A and vitamin E were significantly decreased (P = 0.007, P < 0.001, P = 0.025, respectively); vitamin C was unchanged. Urinary 8-isoprostane correlated positively with interface hepatitis and necroinflammatory score and with hepatic fibrogenesis (type III procollagen peptide). Interface hepatitis correlated negatively with vitamin A and whole blood total glutathione. Oxidant stress, as reflected in blood and urine by a wide range of pro- and antioxidant markers, is a significant feature of AIH and provides a probable mechanism linking hepatic necroinflammation to fibrogenesis and disease progression.
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Affiliation(s)
- Philip W Pemberton
- Department of Gastroenterology, The Liver Unit, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK
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65
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Center SA. Metabolic, antioxidant, nutraceutical, probiotic, and herbal therapies relating to the management of hepatobiliary disorders. Vet Clin North Am Small Anim Pract 2004; 34:67-172, vi. [PMID: 15032126 DOI: 10.1016/j.cvsm.2003.09.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many nutraceuticals, conditionally essential nutrients, and botanical extracts have been proposed as useful in the management of liver disease. The most studied of these are addressed in terms of proposed mechanisms of action, benefits, hazards, and safe dosing recommendations allowed by current information. While this is an area of soft science, it is important to keep an open and tolerant mind, considering that many major treatment discoveries were in fact serendipitous accidents.
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Affiliation(s)
- Sharon A Center
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
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66
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Stanzial AM, Benoni G, Cuzzolin L, Gabrielli GB, Pasino M, Perfetti P, Corrocher R. Urinary nitrite/nitrate concentrations and total antioxidant capacity in patients with chronic hepatitis C in therapy with interferon and ribavirin. J Chemother 2004; 15:584-90. [PMID: 14998085 DOI: 10.1179/joc.2003.15.6.584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
In this study we tried to elucidate the role of nitric oxide (NO) in chronic hepatitis C in relation to antioxidant status, since the mechanisms by which hepatitis C virus (HCV) causes cell damage and the factors underlying its resistance to therapy are not well understood. Before and after one and six months of therapy with alpha-interferon and ribavirin, we measured nitrite/nitrate urinary levels, total antioxidant capacity and selenium serum concentrations in 14 patients with chronic hepatitis C and in 9 healthy subjects. Before therapy, mean urinary nitrite/nitrate levels of patients were not different from those of healthy subjects, but after a 6-month treatment with alpha-interferon and ribavirin, these NO metabolites were higher in virologically negative patients (responders). Moreover, while no changes in selenium were observed in all patients, total antioxidant capacity was significantly higher in non-responders and well correlated with hyperuricemia (due to cell damage) observed in these subjects. Instead, uric acid decreased as free molecule in serum in responders, while we found the excretion of high NO levels as nitrite/nitrate. Our data allow us to hypothesize a role for NO as predictive of the success of therapy, since nitrite/nitrate increase in the urine of some patients precedes disappearance of the virus observed at the end of therapy.
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Affiliation(s)
- A M Stanzial
- Department of Clinical & Experimental Medicine, University of Verona, Italy
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Yi YS, Park SG, Byeon SM, Kwon YG, Jung G. Hepatitis B virus X protein induces TNF-alpha expression via down-regulation of selenoprotein P in human hepatoma cell line, HepG2. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1638:249-56. [PMID: 12878326 DOI: 10.1016/s0925-4439(03)00090-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Human hepatitis B virus X protein (HBx) is associated with the induction of oxidative stress, which is considered significant in the development of liver damage. In this study, we investigated the molecular mechanisms by which HBx induced lipid peroxidation and tumor necrosis factor-alpha (TNF-alpha) expression through regulation of selenoprotein P (SeP) expression in the human hepatoma cell line, HepG2. Forced expression of HBx significantly down-regulated the expression of SeP mRNA and protein in both the cell lysates and the culture medium. Lipid peroxidation increased 2.5-fold when expression of the SeP protein was blocked with a SeP antisense vector. Also, HBx transfection increased lipid peroxidation by 3.0-fold, whereas the hepatitis B virus core protein (HBc) had no significant effects. The induction of lipid peroxidation due to the block in SeP protein expression or treatment with ferric chloride (FeCl(3)) up-regulated the expression levels of TNF-alpha mRNA and protein. The pattern of HBx-induced lipid peroxidation and TNF-alpha up-regulation was reversed by SeP introduction. These results suggest that HBx induces lipid peroxidation via down-regulation of SeP expression, resulting in increased expression of TNF-alpha in the human hepatoma cell line, HepG2.
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Affiliation(s)
- Young-Su Yi
- School of Biological Sciences, Seoul National University, 151-742, Seoul, South Korea
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Aboutwerat A, Pemberton PW, Smith A, Burrows PC, McMahon RFT, Jain SK, Warnes TW. Oxidant stress is a significant feature of primary biliary cirrhosis. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1637:142-50. [PMID: 12633902 DOI: 10.1016/s0925-4439(02)00225-9] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Primary biliary cirrhosis (PBC) is a chronic cholestatic disorder characterised by an immunological, and often granulomatous, attack on bile ducts leading to fibrosis, cirrhosis, liver failure and death. Animal and human studies suggest that oxidant stress plays a key role in progression of other liver diseases, but no comprehensive investigation has been performed previously in PBC. A wide range of lipid peroxidation and antioxidant markers were measured in the blood and urine of 41 patients with histologically confirmed PBC. Lipid peroxidation markers were significantly elevated [plasma and urinary 8-isoprostane, P<0.001; plasma malondialdehyde (MDA), P=0.007] compared to age- and sex-matched controls. The most striking antioxidant depletion occurred with plasma total glutathione where levels were significantly reduced (30% of controls). Total serum antioxidant levels were decreased (P=0.013) and serum selenium and vitamin A were also lower (both P<0.001); vitamins C and E were normal. Most patients had early disease biochemically and were Child-Pugh grade A. Urinary 8-isoprostane correlated positively with Ludwig stage and markers of hepatic injury and cholestasis. This study clearly demonstrates that oxidant stress, as reflected in a comprehensive spectrum of lipid peroxidation and antioxidant markers, is a significant feature of early-stage PBC.
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Affiliation(s)
- Ali Aboutwerat
- The Liver Unit, Department of Gastroenterology, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK
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Abstract
Selenium (Se) is an essential trace element for animals and humans that is obtained from dietary sources including cereals, grains and vegetables. The Se content of plants varies considerably according to its concentration in soil. Plants convert Se mainly into Se-methionine (Se-Met) and incorporate it into protein in place of methionine (Met). Selenocystine (Se-Cys), methyl-Se-Cys and gamma-glutamyl-Se-methyl-Cys are not significantly incorporated into plant protein and are at relatively low levels irrespective of soil Se content. Higher animals are unable to synthesize Se-Met and only Se-Cys was detected in rats supplemented with Se as selenite. Renal regulation is the mode by which whole body Se is controlled. Se is concentrated in hair and nail and it occurs almost exclusively in organic compounds. The potentiating effect of Se deficiency on lipid peroxidation is enhanced in some tissues by concurrent deficiency of copper or manganese. In the in vitro system, the chemical form of Se is an important factor in eliciting cellular responses. Although the cytotoxic mechanisms of selenite and other redoxing Se compounds are still unclear, it has been suggested that they derive from their ability to catalyze the oxidation of thiols and to produce superoxide simultaneously. Selenite-induced cytotoxicity and apoptosis in human carcinoma cells can be inhibited with copper (CuSO(4)) as an antioxidant. High doses of selenite result in induction of 8-hydroxydeoxyguanosine (8-OHdG) in mouse skin cell DNA and in primary human keratinocytes. It may cause DNA fragmentation and decreased DNA synthesis, cell growth inhibition, DNA synthesis, blockade of the cell cycle at the S/G(2)-M phase and cell death by necrosis. In contrast, in cells treated with methylselenocyanate or Se methylselenocysteine, the cell cycle progression was blocked at the G(1) phase and cell death was predominantly induced by apoptosis.
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Affiliation(s)
- H Tapiero
- Université de Paris - Faculté de Pharmacie, CNRS UMR 8612, 5, rue Jean-Baptiste Clément, 94200, Chatenay-Malabry, France.
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Affiliation(s)
- Alan Buchman
- Department of Gastroenterology and Hepatology, Northwestern University Medical School, Chicago, Illinois 60611, USA.
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71
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Affiliation(s)
- Gavin E Arteel
- Laboratory of Hepatobiology and Toxicology, Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Jain SK, Pemberton PW, Smith A, McMahon RFT, Burrows PC, Aboutwerat A, Warnes TW. Oxidative stress in chronic hepatitis C: not just a feature of late stage disease. J Hepatol 2002; 36:805-11. [PMID: 12044532 DOI: 10.1016/s0168-8278(02)00060-0] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND/AIMS Chronic hepatitis C infection is a major world-wide problem, frequently progressing to cirrhosis, liver failure or hepatoma. The pathological mechanisms of disease progression are unclear but oxidant stress may play a role. METHODS Markers of lipid peroxidation, antioxidant status, hepatic fibrogenesis and liver function were measured in blood or urine from 42 chronic hepatitis C patients. Fibrosis was graded histologically in a subgroup of 33 patients. RESULTS The lipid peroxidation marker 8-isoprostane and the ratio of oxidized to reduced glutathione were significantly elevated (P<0.001, P=0.006). The antioxidants glutathione, selenium and vitamins A, C and E were significantly decreased (all P<0.001) compared to age and sex matched controls. Abnormal values were more marked in cirrhotics, but significant changes were also observed in the non-cirrhotic group. The fibrosis score correlated positively with urinary 8-isoprostane and type III procollagen peptide and negatively with vitamin A. CONCLUSIONS Oxidant stress, as reflected in blood and urine by a wide range of pro- and antioxidant markers, is a significant feature of hepatitis C infection. Although more severe in the cirrhotic group, there was clear evidence of oxidant stress in non-cirrhotic patients. Antioxidant therapy may therefore have a role in slowing disease progression to cirrhosis.
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Affiliation(s)
- Sanjiv K Jain
- The Liver Unit, Manchester Royal Infirmary, Manchester, UK
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73
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Navarro-Alarcón M, López-Ga de la Serrana H, Pérez-Valero V, López-Martínez MC. Selenium concentrations in serum of individuals with liver diseases (cirrhosis or hepatitis): relationship with some nutritional and biochemical markers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2002; 291:135-141. [PMID: 12150433 DOI: 10.1016/s0048-9697(01)01088-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Serum concentrations were measured in individuals (n = 50) with liver diseases (cirrhosis and hepatitis) by hydride generation atomic absorption spectrometry in a cross-sectional study. Mean serum selenium levels determined in patients with cirrhosis (n = 12) or with hepatitis (n = 38) were significantly lower (P<0.01) than those measured in control groups mainly due to a decreased liver function. Mean serum selenium concentrations were significantly lower in cirrhotic individuals when compared with patients with hepatitis (P<0.05). Therefore, the severity of the live injury is a factor conditioning the impairment in the selenium body status observed in individuals with hepatopathies. In hepatic patients serum total cholesterol levels showed a significant correlation with serum selenium concentrations (r=0.912, P<0.05) demonstrating the important role of selenium as an antioxidant agent; similarly, gamma-glutamic-transferase levels were significantly correlated with the serum selenium levels (r=-0.803, P<0.05) indicating that when the intensity of the hepatic injury increases (enhancement in serum GGT levels) concomitantly the serum selenium levels decrease significantly. No significant relationships between serum selenium levels and sex or age of patients were observed.
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Affiliation(s)
- M Navarro-Alarcón
- Department of Nutrition and Bromatology, Faculty of Pharmacy, University of Granada, Spain.
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74
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Burk RF. Selenium, an antioxidant nutrient. NUTRITION IN CLINICAL CARE : AN OFFICIAL PUBLICATION OF TUFTS UNIVERSITY 2002; 5:75-9. [PMID: 12134713 DOI: 10.1046/j.1523-5408.2002.00006.x] [Citation(s) in RCA: 182] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Selenium is an essential constituent of a number of enzymes, some of which have antioxidant functions. Deficiency of the element in animals makes them susceptible to injury by certain types of oxidative stress. At least 1 human disease occurs only in selenium-deficient individuals. Therefore, it seems prudent to avoid selenium deficiency. The plasma (or serum) selenium concentration is often used to assess selenium nutritional status. A plasma selenium concentration of 8 micrograms/dL or greater in a healthy subject indicates that plasma selenoproteins are optimized and the subject is selenium replete. The Third National Health and Nutrition Examination Survey determined plasma selenium in 17,630 subjects in the United States. Its results indicate that more than 99% of the subjects studied were selenium replete. The Institute of Medicine has set the Recommended Dietary Allowance for selenium at 55 micrograms per day for adults. Since most estimates of selenium intake in the United States are 80 micrograms per day or greater, routine selenium supplementation is not recommended in the United States.
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Affiliation(s)
- Raymond F Burk
- Division of Gastroenterology, Department of Medicine, Clinical Nutrition Research Unit, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2279, USA.
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75
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Abstract
OBJECTIVES Selenium is a trace mineral that, as a constituent of certain selenoproteins, acts as an antioxidant. Results of studies addressing a cancer protective effect of selenium have been controversial. The present study measured selenoprotein-P, extracellular glutathione peroxidase, and plasma selenium in patients with colon cancer and adenomatous colon polyps to determine whether patients who develop colorectal adenomas or cancer are selenium deficient. METHODS Patients who presented to an endoscopy center for colonoscopy or who were referred to our institution with a newly diagnosed colorectal cancer were offered enrollment in the trial. Each patient underwent phlebotomy, usually immediately after colonoscopy. In all, 103 patients were enrolled in the study. Of these, 33 patients were found to have colorectal cancer, 35 adenomatous colon polyps, and 17 normal examinations. A total of 18 patients had other diagnoses and were not included in the study group. RESULTS The mean age for the colorectal cancer group was 69 yr, for the adenomatous colon polyp group 62 yr, and for the normal group was 56 yr. The adenomatous colon polyp and normal groups were predominantly female. Based on one way analysis of variance tests, there was no significant difference in selenoprotein-P or plasma selenium levels or extracellular glutathione peroxidase activity among the three groups (p = 0.28, 0.098, and 0.35 respectively). CONCLUSIONS The present data suggest that patients with adenomatous colon polyps and those with colorectal cancer are not selenium deficient.
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76
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Abstract
Selenium is present in plasma and tissues in specific and non-specific forms. The experiments reported here were carried out to clarify some factors that affect these forms of the element in plasma. A selenium-replete human subject was given 400 microg of selenium daily for 28 days as selenomethionine and, in a separate experiment, as selenate. The selenomethionine raised plasma and albumin selenium concentrations. Selenate did neither. The molar ratio of methionine to selenium in albumin was approximately 8000 under basal and selenate-supplemented conditions but 2800 after selenomethionine supplementation. This demonstrates that selenium from selenomethionine, but not selenium from selenate, can be incorporated into albumin, presumably as selenomethionine in the methionine pool. Selenocysteine incorporation into albumin was studied in rats using (75)Se-selenocysteine. No evidence was obtained for incorporation of (75)Se into albumin after exogenous administration or endogenous synthesis of (75)Se-selenocysteine. Thus, selenocysteine does not appear to be incorporated non-specifically into proteins as is selenomethionine. These findings are in support of selenomethionine being a non-specific form of selenium that is metabolized as a constituent of the methionine pool and is unaffected by specific selenium metabolic processes. No evidence was found for non-specific incorporation of selenium into plasma proteins when it was administered as selenate or as selenocysteine. These forms of the element appear to be metabolized by specific selenium metabolic processes.
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Affiliation(s)
- R F Burk
- Division of Gastroenterology, Department of Medicine and Clinical Nutrition Research Unit, Vanderbilt University School of Medicine, Nashville, TN 37221, USA.
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Persson-Moschos ME, Stavenow L, Akesson B, Lindgärde F. Selenoprotein P in plasma in relation to cancer morbidity in middle-aged Swedish men. Nutr Cancer 2000; 36:19-26. [PMID: 10798212 DOI: 10.1207/s15327914nc3601_4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The premorbid level of selenoprotein P in plasma from subjects with cancer at different sites was compared with that from control subjects in a nested case-control study. A health screening of 12,500 middle-aged men was performed during 1974-1982 in Malmö, Sweden, and from the 400 cancer cases that were identified during follow-up until the end of 1988, 302 plasma samples were available for analysis of selenoprotein P. Two living controls per case of the same screening day and age were chosen. Selenoprotein P levels in subgroups of major cancer sites were lower in cases than in controls for the respiratory tract (1.20 and 1.30 arbitrary units, respectively; p < 0.05) cancer group. The odds ratio for overall cancer risk in the lowest quintile of selenoprotein P level compared with that in the highest was 5.2 [p (for trend) = 0.01]. In subgroups of major cancer sites, the odds ratios for cancer risk in the lowest tertile compared with the highest were 6.0 [p (for trend) = 0.004] in the respiratory tract and 3.4 [p (for trend) = 0.002] in the digestive tract. In cases + controls, selenoprotein P was lower in smokers than in nonsmokers (p < 0.05). Selenoprotein P was significantly correlated to plasma albumin, fasting blood glucose, and body mass index and inversely correlated to plasma alpha 1-antitrypsin and gamma-glutamyl transferase. The results suggest that a low plasma selenoprotein P level is associated with higher future risk of respiratory and digestive tract cancer in middle-aged men.
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Reyes H, Báez ME, González MC, Hernández I, Palma J, Ribalta J, Sandoval L, Zapata R. Selenium, zinc and copper plasma levels in intrahepatic cholestasis of pregnancy, in normal pregnancies and in healthy individuals, in Chile. J Hepatol 2000; 32:542-9. [PMID: 10782901 DOI: 10.1016/s0168-8278(00)80214-7] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND/AIMS Low blood Se levels have been previously shown in normal pregnancies (third trimester) and significantly lower levels in patients with intrahepatic cholestasis of pregnancy (ICP), in Finland and in Chile, suggesting that a low or marginal dietary availability of Se may contribute to the pathogenesis of this disease. The aim of this study was to investigate whether a temporal change in plasma concentration of Se, and seasonal fluctuations in plasma concentrations of Se, Zn and Cu, could coincide with changes in the prevalence of ICP. METHODS A cross-sectional cohort study was done including 21 ICP patients, 98 women in the third trimester of a normal pregnancy, 29 non-pregnant women, and also 13 individuals (seven non-pregnant women and six men) who had been studied 9 years before. Plasma Se, Zn and Cu were measured by atomic spectroscopy. Plasma Se levels in the present study were compared to the results obtained 5 to 7 years before, employing identical methodology in similar population samples. RESULTS Plasma Se concentrations in non-pregnant women were higher than in the previous study: 1.43+/-0.34 micromol/l vs 0.85+/-0.13; p<0.001. In comparison to non-pregnant women, normal pregnancies near term had lower plasma levels of Se: 1.08+/-0.25 micromol/l; p<0.01, and Zn: 17.90+/-3.61 micromol/l vs 19.71+/-3.21; p<0.05, but higher plasma levels of Cu: 34.35+/-7.12 micromol/l vs 20.62+/-3.34; p<0.01. In normal pregnancies, plasma Se concentration was significantly higher in summer (1.34+/-0.19 micromol/l) than in the other seasons, while Zn and Cu diminished. Similar to previous studies, ICP patients had significantly lower Se plasma levels than normal pregnancies: 0.94+/-0.12 micromol/l, p<0.05, and Cu levels were significantly higher: 50.80+/-7.02 micromol/l, p<0.01. Cu plasma levels correlated with the biochemical severity of the disease. Zn did not change in ICP. CONCLUSIONS The present study shows that the decrease in the prevalence of ICP in Chile during the last decade coincides with an increase in plasma Se levels. Its lower incidence during summer coincides with a higher plasma Se concentration in summer than in other seasons, as observed in normal pregnancies.
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Affiliation(s)
- H Reyes
- Department of Medicine, Hospital del Salvador and Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago de Chile.
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