Changes in pathology and iron regulation in guinea pigs in relation to the lipid content of the diet

CHANGES IN PATHOLOGY AND IRON REGULATION IN GUINEA PIGS IN RELATION TO THE LIPID CONTENT OF THE DIET YE PENG (M. Med, Sichuan Univ., China) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF BIOCHEMISTRY NATIONAL UNIVERSITY OF SINGAPORE 2012 DECLARATION I hereby declare that the thesis is my original work and it has been written by me in its entirety. I have duly acknowledged all the sources of information which have been used in the thesis. This thesis has also not been submitted for any degree in any university previously. _________________ Ye Peng Aug 2012 i ACKNOWLEDGEMENTS Firstly, special thanks to my parents and my wife for their support throughout my candidature. I would like to give thanks to my supervisor, Professor Barry Halliwell, for his invaluable guidance and continuous support through my study. I also wish to thank Dr. Irwin Cheah Kee-Mun for coaching me throughout my project. Special thanks to Professor Frank Watt and Dr. Ren Minqin from Department of Physics, Faculty of Science, National University of Singapore for helping conduct nuclear microscopy technology on artery sections. Special thanks to Aina Hoi for assisting in animal sacrifice and sample collection. Last but not least, many thanks to my lab mates and friends, Dr. Tang Soon Yew, Wu Yilian, Long Lee Hua, Yew Shze Keong Terry, Dr. Wong Yee Ting, Dr. Jan Gruber, Ng Li Fang, Manickaratnam Ranjan, Dr. Sebastian Schaffer, Lam Yuk Man Vanessa, Dr. Alvin Loo, Ho Rongjian, Dr. Jetty Lee, Sherry Huang and Wang Huansong for their everyday help. ii TABLES OF CONTENTS Page Acknowledgements ii Tables of contents iii Abstract viii List of tables x List of figures xii List of abbreviations and symbols xv CHAPTER INTRODUCTION 1.1 Introduction 1.2 Role of cholesterol in disease 1.2.1 Cholesterol 1.2.2 Cardiovascular disease and atherosclerosis 1.2.3 Non-alcoholic fatty liver disease 1.3 Oxidative stress 11 1.3.1 What is oxidative stress? 11 1.3.2 Role of oxidative stress in disease 12 1.3.2.1 Role of oxidative stress in cardiovascular disease 13 1.3.2.2 Non-alcoholic fatty liver disease 14 1.3.3 Markers of oxidative stress 1.3.3.1 Biomarkers of lipid peroxidation 18 18 iii 1.3.3.2 Biomarkers of protein damage by RS 1.3.4 Management of oxidative stress 1.4 Iron and its role in oxidative-stress-induced damage 21 22 23 1.4.1 Role of iron in the body 23 1.4.2 Role of iron in disease 24 1.4.2.1 Cardiovascular disease 25 1.4.2.2 Non-alcoholic fatty liver disease 26 1.4.3 Management of iron in body 1.5 Guinea pig as an animal model 1.5.1 Guinea pig as an animal model for studying diet-induced 29 33 34 atherosclerosis 1.5.2 Guinea pig as an animal model for studying diet-induced 36 non-alcoholic fatty liver disease 1.6 Aims of the study 37 CHAPTER EXPERIMENTAL PROCEDURES 2.1 Animal studies 39 2.1.1 Diets 39 2.1.2 Animals 41 2.2 Material 42 2.3 Assays and analytical methods 43 2.3.1 TBARS assay 43 iv 2.3.2 Saliva cortisol measurement 44 2.3.3 Gas chromatography- mass spectrometry 45 2.3.3.1 Determination of oxidative markers in plasma 45 2.3.3.2 Determination of oxidative markers in liver 48 2.3.4 Cryo-sectioning 50 2.3.5 Hematoxylin and Eosin staining 51 2.3.6 Oil red staining 52 2.3.7 Sirius red staining 52 2.3.8 Ferrozine assay for total iron content 53 2.3.9 Cholesterol assay 54 2.3.10 High performance liquid chromatography 55 2.3.11 Alanine transaminase activity test 56 2.3.12 Gamma-glutamyl transpeptidase activity assay 56 2.3.13 Transferrin ELISA 57 2.3.14 Hepcidin ELISA 57 2.3.15 Protein carbonyl assay 58 2.3.16 Ferritin ELISA 59 2.3.17 Transferrin receptor-2 ELISA assay 59 2.3.18 Heme determination assay 60 2.3.19 Perl’s staining 60 2.3.20 Hydroxyproline assay 61 2.3.21 Iron/zinc analysis on aorta sections 61 v 2.3.22 Plasma HDL and LDL/VLDL assay 62 2.3.23 Liver HO-1 activity assay 63 2.4 Data analysis 64 CHAPTER BASIC OBSERVATIONS IN THE GUINEA PIG 3.1 Weight gain in guinea pigs and total food consumed 65 3.2 Saliva stress marker concentrations and food lipid peroxidation 69 levels and iron contents 3.3 Organ weight 71 CHAPTER PATHOLOGICAL CHANGES IN PLASMA AND BLOOD VESSELS 4.1 Plasma cholesterol and lipoprotein profile 78 4.2 Plasma markers of oxidative stress 82 4.3 Atherosclerotic changes in artery 88 4.4 Plasma ascorbic acid level 93 4.5 Conclusion 95 CHAPTER PATHOLOGICAL CHANGES IN LIVER AND SPLEEN 5.1 Hepatic steatosis 96 5.1.1 Histological changes 96 5.1.2 Liver damage markers 98 5.2 Liver cholesterol and markers of oxidative stress 100 vi 5.3 Iron regulation 108 5.3.1 Hepatic iron contents 108 5.3.2 Hepatic heme, ferritin, and hemosiderin 111 5.3.3 Transferrin, hepcidin, and iron concentrations in plasma 118 5.3.4 Transferrin receptor-2 expression in liver 121 5.3.5 Heme oxygenase-1 expression in the liver 123 5.4 Hepatosplenomegaly 125 5.4.1 Hydroxyproline content in liver 125 5.4.2 Spleen histological changes 128 5.4.3 Spleen iron content 130 5.4.4 Hemosiderin in spleen 132 5.5 Conclusion LIST OF REFERENCES 134 136 vii ABSTRACT Studies have revealed that elevated levels of iron promote the formation of atherosclerotic plaques and may contribute to the disease progression, while zinc was found to have a beneficial effect in rabbits. Guinea pigs have been suggested to be a realistic animal model for studying atherosclerosis, as their plasma lipoprotein profile closely mimics that of humans. This study initially attempted to further investigate the changes in iron and zinc levels in the atherosclerotic plaque, elemental and biochemical changes in the intima during initiation and progression of atherosclerosis over time and cause-consequence relationship between oxidative stress and atherosclerosis. For that purpose, male guinea pigs were fed a moderate cholesterol (10% fat, 0.17% cholesterol) or high cholesterol diet (10% fat, 0.33% cholesterol) alongside controls (4% fat, no cholesterol) for 2, 4, or months. We found that dietary cholesterol significantly raised the cholesterol concentrations in plasma and liver. Plasma and liver cholesterol oxidation products (24-OH cholesterol, 7α-OH cholesterol, 7β-OH cholesterol and 7-ketocholesterol) were also elevated in cholesterol-fed groups. However, there was no significant change in plasma and liver lathosterol, F2-isoprostanes or arachidonic acid levels. Unfortunately the diets failed to significantly alter atherosclerotic burden in the animals although iron/zinc concentrations within the few lesions (possibly early plaques) observed were suggestive of early atherosclerotic plaque formation and viii consistent with previous data. It may be that previous work on cholesterol-induced atherosclerosis in the guinea pig model in the literature could be questionable. On the other hand, significant liver damage and indications of advanced fatty liver disease were observed, together with decreased plasma hepcidin and transferrin levels in cholesterol-fed groups. Liver iron and cholesterol were shown to be increased in cholesterol-fed groups and a high correlation between them was observed. Plasma iron levels were shown to be increased, probably due to decreased plasma hepcidin. No significant difference was shown in liver ferritin, transferrin receptor-2 levels and heme oxygenase-1 activities between the three dietary groups. Liver hemosiderin depositions were found in cholesterol-fed groups but not in control group, which, together with almost normal oxidative stress levels, suggests that the excess iron was safely sequestered in hemosiderin. Thirdly, spleen enlargement was also found in cholesterol-fed groups, which could be explained by possible portal vein hypertension, consistent with the findings of increased liver collagen levels in those animals. There was a continuous rise in spleen iron with age in all groups, but no significant difference in spleen total iron levels was found between the groups. Spleen heme levels significantly decreased in high cholesterol group. However, spleen hemosiderin deposition was seen in all groups and no significant difference was found between them. ix Ohtake T, Saito H, Hosoki Y, Inoue M, Miyoshi S, Suzuki Y, Fujimoto Y, Kohgo Y. (2007) Hepcidin is down-regulated in alcohol loading. Alcohol Clin Exp Res. 2007 Jan;31(1 Suppl):S2-8. Oishi T, Terai S, Iwamoto T, Takami T, Yamamoto N, Sakaida I. (2011) Splenectomy reduces fibrosis and preneoplastic lesions with increased triglycerides and essential fatty acids in rat liver cirrhosis induced by a choline-deficient L-amino acid-defined diet. Hepatol Res. 2011 May;41(5):463-74. Okabe K, Hayashi M, Yoshida I, Nishimura K, Fukushima N, Tsujiuchi T. (2011) Distinct DNA methylation patterns of lysophosphatidic acid receptor genes during rat hepatocarcinogenesis induced by a choline-deficient L-amino acid-defined diet. Arch Toxicol. 2011 Oct;85(10):1303-10. Olivecrona T, Bengsston-Olivecrona G. (1993) Lipoprotein lipase and hepatic lipase. Curr Opin Lipidol. 1993 Jun;4(3):187-96. Oliver MF. (1991) Might treatment of hypercholesterolaemia increase non-cardiac mortality? Lancet. 1991 Jun 22;337(8756):1529-31. Olkkonen VM, Lehto M. (2004) Oxysterols and oxysterol binding proteins: role in lipid metabolism and atherosclerosis. Ann Med. 2004;36(8):562-72. Olson RE. (1998) Discovery of the lipoproteins, their role in fat transport and their significance as risk factors. J Nutr. 1998 Feb;128(2 Suppl):439S-443S. Ordway GA, Garry DJ. (2004) Myoglobin: an essential hemoprotein in striated muscle. J Exp Biol. 2004 Sep;207(Pt 20):3441-6. Ostwald R, Yamanaka W, Light M, Kroes J. (1977) The time course of metabolic 167 changes induced by dietary cholesterol in guinea pigs. Atherosclerosis. 1977 Jan;26(1):41-53. Otogawa K, Kinoshita K, Fujii H, Sakabe M, Shiga R, Nakatani K, Ikeda K, Nakajima Y, Ikura Y, Ueda M, Arakawa T, Hato F, Kawada N. (2007) Erythrophagocytosis by liver macrophages (Kupffer cells) promotes oxidative stress, inflammation, and fibrosis in a rabbit model of steatohepatitis: implications for the pathogenesis of human nonalcoholic steatohepatitis. Am J Pathol. 2007 Mar;170(3):967-80. Padilla-Carlin DJ, McMurray DN, Hickey AJ. (2008) The Guinea Pig as a Model of Infectious Diseases. Comp Med. 2008 Aug;58(4):324-40. Parthasarathy S, Steinberg D, Witztum JL. (1992) The role of oxidized low-density lipoproteins in the pathogenesis of atherosclerosis. Annu Rev Med. 1992;43:219-25. Percy ME. (1984) Catalase: an old enzyme with a new role? Can J Biochem Cell Biol. 1984 Oct;62(10):1006-14. Pessayre D, Fromenty B. (2005) NASH: a mitochondrial disease. J. Hepatol. 2005; 42: 928–40 Pessayre D. (2007) Role of mitochondria in non-alcoholic fatty liver disease. J Gastroenterol Hepatol. 2007 Jun;22 Suppl 1:S20-7. Philippe MA, Ruddell RG, Ramm GA. (2007) Role of iron in hepatic fibrosis: one piece in the puzzle. World J Gastroenterol. 2007 Sep 21;13(35):4746-54. Pogozelski WK, Tullius TD. (1998) Oxidative Strand Scission of Nucleic Acids: 168 Routes Initiated by Hydrogen Abstraction from the Sugar Moiety. Chem Rev. 1998 May 7;98(3):1089-1108. Poli G, Parola M. (1997) Oxidative damage and fibrogenesis. Free Radic Biol Med. 1997;22(1-2):287-305. Poli G, Schaur RJ. (2000) 4-Hydroxynonenal in the pathomechanisms of oxidative stress. IUBMB Life. 2000 Oct-Nov;50(4-5):315-21. Ponka P, Lok CN. (1999) The transferrin receptor: role in health and disease. Int J Biochem Cell Biol. 1999 Oct;31(10):1111-37. Postic C, Girard J. (2008) Contribution of de novo fatty acid synthesis to hepatic steatosis and insulin resistance: lessons from genetically engineered mice. J Clin Invest. 2008 Mar;118(3):829-38. Powell EE, Ali A, Clouston AD, Dixon JL, Lincoln DJ, Purdie DM, Fletcher LM, Powell LW, Jonsson JR. (2005) Steatosis is a cofactor in liver injury in hemochromatosis. Gastroenterology. 2005 Dec;129(6):1937-43. Praticò D. (2001) Lipid peroxidation in mouse models of atherosclerosis. Trends Cardiovasc Med. 2001 Apr-May;11(3-4):112-6. Puppione DL, Sardet C, Yamanaka W, Ostwald R, Nichols AV. (1971) Plasma lipoproteins of cholesterol-fed guinea pigs. Biochim Biophys Acta. 1971 Mar 16;231(2):295-301. Qiao Y, Yokoyama M, Kameyama K, Asano G. (1993) Effect of vitamin E on vascular integrity in cholesterol-fed guinea pigs. Arterioscler Thromb. 1993 Dec;13(12):1885-92. 169 Ramjiganesh T, Roy S, Nicolosi RJ, Young TL, McIntyre JC, Fernandez ML. (2000) Corn husk oil lowers plasma LDL cholesterol concentrations by decreasing cholesterol absorption and altering hepatic cholesterol metabolism in guinea pigs. J Nutr Biochem. 2000 Jul-Aug;11(7-8):358-66. Ramm GA, Ruddell RG. (2005) Hepatotoxicity of iron overload: mechanisms of iron-induced hepatic fibrogenesis. Semin Liver Dis. 2005 Nov;25(4):433-49. Ren M, Watt F, Huat BT, Halliwell B. (2003) Correlation of iron and zinc levels with lesion depth in newly formed atherosclerotic lesions. Free Radic Biol Med. 2003 Mar 15;34(6):746-52. Ren M, Rajendran R, Pan N, Tan BK, Ong WY, Watt F, Halliwell B. (2005) The iron chelator desferrioxamine inhibits atherosclerotic lesion development and decreases lesion iron concentrations in the cholesterol-fed rabbit. Free Radic Biol Med. 2005 May 1;38(9):1206-11. Ren M, Rajendran R, Ning P, Tan Kwong Huat B, Choon Nam O, Watt F, Jenner A, Halliwell B. (2006) Zinc supplementation decreases the development of atherosclerosis in rabbits. Free Radic Biol Med. 2006 Jul 15;41(2):222-5. Ricciardolo FL, Nijkamp F, De Rose V, Folkerts G. (2008) The guinea pig as an animal model for asthma. Curr Drug Targets. 2008 Jun;9(6):452-65. Rice BH, Kraft J, Destaillats F, Bauman DE, Lock AL. (2010) Ruminant-produced trans-fatty acids raise plasma total and small HDL particle concentrations in male Hartley guinea pigs. J Nutr. 2010 Dec;140(12):2173-9. Riemer J, Hoepken HH, Czerwinska H, Robinson SR, Dringen R. (2004) 170 Colorimetric ferrozine-based assay for the quantitation of iron in cultured cells. Anal Biochem. 2004 Aug 15;331(2):370-5. Robb A, Wessling-Resnick M. (2004) Regulation of transferrin receptor protein levels by transferrin. Blood. 2004 Dec 15;104(13):4294-9. Roche M, Rondeau P, Singh NR, Tarnus E, Bourdon E. (2008) The antioxidant properties of serum albumin. FEBS Lett. 2008 Jun 11;582(13):1783-7. Rolo AP, Teodoro JS, Palmeira CM. (2012) Role of oxidative stress in the pathogenesis of nonalcoholic steatohepatitis. Free Radic Biol Med. 2012 Jan 1;52(1):59-69. Ross R, Glomset JA. (1973) Atherosclerosis and the arterial smooth muscle cell: proliferation of smooth muscle is a key event in the genesis of the lesions of atherosclerosis. Science. 1973 Jun 29;180(4093):1332-9. Roy S, Vega-Lopez S, Fernandez ML. (2000) Gender and hormonal status affect the hypolipidemic mechanisms of dietary soluble fiber in guinea pigs. J Nutr. 2000 Mar;130(3):600-7. Sable-Amplis R, Sicart R. (1983) Relationship between aorta cholesterol content and plasma lipids in guinea pigs fed an atherogenic diet. Atherosclerosis. 1983 Sep;48(3):295-9. Saborido A, Soblechero L, Megías A. (2005) Isolated respiring heart mitochondria release reactive oxygen species in states and 3. Free Radic Res. 2005 Sep;39(9):921-31. Sadahira Y, Mori M. (1999) Role of the macrophage in erythropoiesis. Pathol Int. 171 1999 Oct;49(10):841-8. Salonen JT, Nyyssönen K, Korpela H, Tuomilehto J, Seppänen R, Salonen R. (1992) High stored iron levels are associated with excess risk of myocardial infarction in eastern Finnish men. Circulation. 1992 Sep;86(3):803-11. San Martin CD, Garri C, Pizarro F, Walter T, Theil EC, Núñez MT. (2008) Caco-2 intestinal epithelial cells absorb soybean ferritin by mu2 (AP2)-dependent endocytosis. J Nutr. 2008 Apr;138(4):659-66. Sancar A, Lindsey-Boltz LA, Unsal-Kaçmaz K, Linn S. (2004) Molecular mechanisms of mammalian DNA repair and the DNA damage checkpoints. Annu Rev Biochem. 2004;73:39-85. Sardet C, Hansma H, Ostwald R. (1972) Characterization of guinea pig plasma lipoproteins the appearance of new lipoproteins in response to dietary cholesterol. J Lipid Res. 1972 Sep;13(5):624-39. Sass G, Barikbin R, Tiegs G. (2012) The multiple functions of heme oxygenase-1 in the liver. Z Gastroenterol. 2012 Jan;50(1):34-40. Sato M, Suzuki S, Senoo H. (2003) Hepatic stellate cells: unique characteristics in cell biology and phenotype. Cell Struct Funct. 2003 Apr;28(2):105-12. Sauberlich HE. (1978) Pharmacology of Vitamin C. Annu Rev Nutr. 1994;14:371-91. Sawamura T, Kume N, Aoyama T, Moriwaki H, Hoshikawa H, Aiba Y, Tanaka T, Miwa S, Katsura Y, Kita T, Masaki T. (1997) An endothelial receptor for oxidized low-density lipoprotein. Nature. 1997 Mar 6;386(6620):73-7. 172 Schaeffer DO, Donnelly TM. (1997) Disease problems of guinea pigs and chinchillas, p. 260-281. In E. V. Hillyer and K. E. Quesenberry (ed.), Ferrets, rabbits, and rodents: clinical medicine and surgery. W.B. Saunders Co., Philadelphia. Schwemmer M, Sommer O, Koeckerbauer R, Bassenge E. (2000) Cardiovascular dysfunction in hypercholesterolemia associated with enhanced formation of AT1-receptor and of eicosanoids. J Cardiovasc Pharmacol Ther. 2000 Jan;5(1):59-68. Sedlak TW, Snyder SH. (2004) Bilirubin benefits: cellular protection by a biliverdin reductase antioxidant cycle. Pediatrics. 2004 Jun;113(6):1776-82. Sekiguchi M. (1996) MutT-related error avoidance mechanism for DNA synthesis. Genes Cells. 1996 Feb;1(2):139-45. Seljeskog E, Hervig T, Mansoor MA. (2006) A novel HPLC method for the measurement of thiobarbituric acid reactive substances (TBARS). A comparison with a commercially available kit. Clin Biochem. 2006 Sep;39(9):947-54. Semenza GL. (2007) Oxygen-dependent regulation of mitochondrial respiration by hypoxia-inducible factor 1. Biochem J. 2007 Jul 1;405(1):1-9. Sevanian A, Davies KJ, Hochstein P. (1991) Serum urate as an antioxidant for ascorbic acid. Am J Clin Nutr. 1991 Dec;54(6 Suppl):1129S-1134S. Shan Y, Pepe J, Lu TH, Elbirt KK, Lambrecht RW, Bonkovsky HL. (2000) Induction of the heme oxygenase-1 gene by metalloporphyrins. Arch Biochem Biophys. 173 2000 Aug 15;380(2):219-27. Sharma R, Yang Y, Sharma A, Awasthi S, Awasthi YC. (2004) Antioxidant role of glutathione S-transferases: protection against oxidant toxicity and regulation of stress-mediated apoptosis. Antioxid Redox Signal. 2004 Apr;6(2):289-300. Sharman MJ, Fernandez ML, Zern TL, Torres-Gonzalez M, Kraemer WJ, Volek JS. (2008) Replacing dietary carbohydrate with protein and fat decreases the concentrations of small LDL and the inflammatory response induced by atherogenic diets in the guinea pig. J Nutr Biochem. 2008 Nov;19(11):732-8. Shono T, Ono M, Izumi H, Jimi SI, Matsushima K, Okamoto T, Kohno K, Kuwano M. (1996) Involvement of the transcription factor NF-kappaB in tubular morphogenesis of human microvascular endothelial cells by oxidative stress. Mol Cell Biol. 1996 Aug;16(8):4231-9. Simonen P, Kotronen A, Hallikainen M, Sevastianova K, Makkonen J, Hakkarainen A, Lundbom N, Miettinen TA, Gylling H, Yki-Järvinen H. (2011) Cholesterol synthesis is increased and absorption decreased in non-alcoholic fatty liver disease independent of obesity. J Hepatol. 2011 Jan;54(1):153-9. Sirinian MI, Belleudi F, Campagna F, Ceridono M, Garofalo T, Quagliarini F, Verna R, Calandra S, Bertolini S, Sorice M, Torrisi MR, Arca M. (2005) Adaptor protein ARH is recruited to the plasma membrane by low density lipoprotein (LDL) binding and modulates endocytosis of the LDL/LDL receptor complex in hepatocytes. J Biol Chem. 2005 Nov 18;280(46):38416-23. Sjögren M, Mielke M, Gustafson D, Zandi P, Skoog I. (2006) Cholesterol and 174 Alzheimer's disease--is there a relation? Mech Ageing Dev. 2006 Feb;127(2):138-47. Skinner AM, Turker MS. (2005) Oxidative mutagenesis, mismatch repair, and aging. Sci Aging Knowledge Environ. 2005 Mar 2;2005(9):re3. Sligar SG. (1976) Coupling of spin, substrate, and redox equilibria in cytochrome P450. Biochemistry. 1976 Nov 30;15(24):5399-406. Sluse FE. (2012) Uncoupling proteins: molecular, functional, regulatory, physiological and pathological aspects. Adv Exp Med Biol. 2012;942:137-56. Smith BW, Adams LA. (2011) Non-alcoholic fatty liver disease. Crit Rev Clin Lab Sci. 2011 May-Jun;48(3):97-113. Smith C, Mitchinson MJ, Aruoma OI, Halliwell B. (1992) Stimulation of lipid peroxidation and hydroxyl-radical generation by the contents of human atherosclerotic lesions. Biochem J. 1992 Sep 15;286 ( Pt 3):901-5. Solís Herruzo JA, García Ruiz I, Pérez Carreras M, Muñoz Yagüe MT. (2006) Non-alcoholic fatty liver disease. From insulin resistance to mitochondrial dysfunction. Rev Esp Enferm Dig. 2006 Nov;98(11):844-74. Sookoian S, Pirola CJ. Non-alcoholic fatty liver disease is strongly associated with carotid atherosclerosis: a systematic review. J Hepatol. 2008 Oct;49(4):600-7. Sottero B, Gamba P, Gargiulo S, Leonarduzzi G, Poli G. (2009) Cholesterol oxidation products and disease: an emerging topic of interest in medicinal chemistry. Curr Med Chem. 2009;16(6):685-705. Spady DK, Turley SD, Dietschy JM. (1985) Rates of low density lipoprotein uptake 175 and cholesterol synthesis are regulated independently in the liver. J Lipid Res. 1985 Apr;26(4):465-72. Spruss A, Kanuri G, Wagnerberger S, Haub S, Bischoff SC, Bergheim I. (2009) Toll-like receptor is involved in the development of fructose-induced hepatic steatosis in mice. Hepatology. 2009 Oct;50(4):1094-104. Stadler N, Lindner RA, Davies MJ. (2004) Direct detection and quantification of transition metal ions in human atherosclerotic plaques: evidence for the presence of elevated levels of iron and copper. Arterioscler Thromb Vasc Biol. 2004 May;24(5):949-54. Stremmel W, Karner M, Manzhalii E, Gilles W, Herrmann T, Merle U. (2007) Liver and iron metabolism--a comprehensive hypothesis for the pathogenesis of genetic hemochromatosis. Z Gastroenterol. 2007 Jan;45(1):71-5. Subramaniam VN, Summerville L, Wallace DF. (2002) Molecular and cellular characterization of transferrin receptor 2. Cell Biochem Biophys. 2002;36(2-3):235-9. Subramanian S, Goodspeed L, Wang S, Kim J, Zeng L, Ioannou GN, Haigh WG, Yeh MM, Kowdley KV, O'Brien KD, Pennathur S, Chait A. (2011) Dietary cholesterol exacerbates hepatic steatosis and inflammation in obese LDL receptor-deficient mice. J Lipid Res. 2011 Sep;52(9):1626-35. Sugadev R, Ponnuswamy MN, Sekar K. (2011) Structural analysis of NADPH depleted bovine liver catalase and its inhibitor complexes. Int J Biochem Mol Biol. 2011;2(1):67-77. 176 Sugamura K, Keaney JF Jr. (2011) Reactive oxygen species in cardiovascular disease. Free Radic Biol Med. 2011 Sep 1;51(5):978-92. Sullivan JL. (1981) Iron and the sex difference in heart disease risk. Lancet. 1981 Jun 13;1(8233):1293-4. Sullivan JL. (2003) Are menstruating women protected from heart disease because of, or in spite of, estrogen? Relevance to the iron hypothesis. Am Heart J. 2003 Feb;145(2):190-4. Sumida Y, Nakashima T, Yoh T, Furutani M, Hirohama A, Kakisaka Y, Nakajima Y, Ishikawa H, Mitsuyoshi H, Okanoue T, Kashima K, Nakamura H, Yodoi J. (2003) Serum thioredoxin levels as a predictor of steatohepatitis in patients with nonalcoholic fatty liver disease. J Hepatol. 2003 Jan;38(1):32-8. Sumida Y, Yoshikawa T, Okanoue T. (2009) Role of hepatic iron in non-alcoholic steatohepatitis. Hepatol Res. 2009 Mar;39(3):213-22. Swain J, Gutteridge JM. (1995) Prooxidant iron and copper, with ferroxidase and xanthine oxidase activities in human atherosclerotic material. FEBS Lett. 1995 Jul 24;368(3):513-5. Tararak EM. (1968) Regression of experimental atherosclerosis of the aorta in guinea pigs. Bull Exper Biol Med 1968;67:118-21. Tenhunen R, Marver HS, Schmid R. (1968) The enzymatic conversion of heme to bilirubin by microsomal heme oxygenase. Proc Natl Acad Sci U S A. 1968 Oct;61(2):748-55. Theil EC. (2011) Iron homeostasis and nutritional iron deficiency. J Nutr. 2011 Apr 177 1;141(4):724S-728S. Thornalley PJ, Argirova M, Ahmed N, Mann VM, Argirov O, Dawnay A. (2000) Mass spectrometric monitoring of albumin in uremia. Kidney Int. 2000 Nov;58(5):2228-34. Thornalley PJ. (2005) Measurement of protein glycation, glycated peptides, and glycation free adducts. Perit Dial Int. 2005 Nov-Dec;25(6):522-33. Toyokuni S, Hirao A, Wada T, Nagai R, Date A, Yoshii T, Akatsuka S, Yamashita Y, Kawada A. (2011) Age- and sun exposure-dependent differences in 8-hydroxy-2'-deoxyguanosine and N-(carboxymethyl)lysine in human epidermis. J Clin Biochem Nutr. 2011 Sep;49(2):121-4. Trinder D, Fox C, Vautier G, Olynyk JK. (2002) Molecular pathogenesis of iron overload. Gut. 2002 Aug;51(2):290-5. Trinder D, Baker E. (2003) Transferrin receptor 2: a new molecule in iron metabolism. Int J Biochem Cell Biol. 2003 Mar;35(3):292-6. Tsushima Y, Endo K. (2000) Spleen enlargement in patients with nonalcoholic fatty liver: correlation between degree of fatty infiltration in liver and size of spleen. Dig Dis Sci. 2000 Jan;45(1):196-200. Tuomainen TP, Diczfalusy U, Kaikkonen J, Nyyssönen K, Salonen JT. (2003) Serum ferritin concentration is associated with plasma levels of cholesterol oxidation products in man. Free Radic Biol Med. 2003 Oct 15;35(8):922-8. Valavanidis A, Vlachogianni T, Fiotakis C. (2009) 8-hydroxy-2' -deoxyguanosine (8-OHdG): A critical biomarker of oxidative stress and carcinogenesis. J 178 Environ Sci Health C Environ Carcinog Ecotoxicol Rev. 2009 Apr;27(2):120-39. Vasandani C, Kafrouni AI, Caronna A, Bashmakov Y, Gotthardt M, Horton JD, Spady DK. (2002) Upregulation of hepatic LDL transport by n-3 fatty acids in LDL receptor knockout mice. J Lipid Res. 2002 May;43(5):772-84. Verdier F, Chazal I, Descotes J. (2004) Anaphylaxis models in the guinea-pig. Toxicology. 1994 Sep 22;93(1):55-61. Virchow, Rudolf (1856). Phlogose und Thrombose im Gefäßsystem Gesammelte Abhandlungen zur wissenschaftlichen Medizin. Germany: Staatsdruckerei Frankfurt. Wang W, Knovich MA, Coffman LG, Torti FM, Torti SV. (2010) Serum ferritin: Past, present and future. Biochim Biophys Acta. 2010 Aug;1800(8):760-9. Waterman MR, Simpson ER. (1985) Regulation of the biosynthesis of cytochromes P-450 involved in steroid hormone synthesis. Mol Cell Endocrinol. 1985 Feb;39(2):81-9. West K, Ramjiganesh T, Roy S, Keller BT, Fernandez ML. (2002) SC-435, an ileal, apical sodium-dependent bile acid transporter inhibitor (ASBT) alters hepatic cholesterol metabolism low-density-lipoprotein-cholesterol and lowers concentrations in guinea plasma pigs. J Pharmacol Exp Theraup. 2002;303:291-299. Willner IR, Waters B, Patil SR, Reuben A, Morelli J, Riely CA. (2001) Ninety patients with nonalcoholic steatohepatitis: insulin resistance, familial tendency, and severity of disease. Am J Gastroenterol. 2001 179 Oct;96(10):2957-61. Wilson S, Vennervald BJ, Dunne DW. (2011) Chronic hepatosplenomegaly in African school children: a common but neglected morbidity associated with schistosomiasis and malaria. PLoS Negl Trop Dis. 2011 Aug;5(8):e1149. Woessner, JF, Jr. (1961) The determination of hydroxyproline in tissue and protein samples containing small proportions of this imino acid. Arch Biochem Biophys. 1961 May;93:440-7. Wouters K, van Gorp PJ, Bieghs V, Gijbels MJ, Duimel H, Lütjohann D, Kerksiek A, van Kruchten R, Maeda N, Staels B, van Bilsen M, Shiri-Sverdlov R, Hofker MH. (2008) Dietary cholesterol, rather than liver steatosis, leads to hepatic inflammation in hyperlipidemic mouse models of nonalcoholic steatohepatitis. Hepatology. 2008 Aug;48(2):474-86. Wu ML, Ho YC, Yet SF. (2011) A central role of heme oxygenase-1 in cardiovascular protection. Antioxid Redox Signal. 2011 Oct 1;15(7):1835-46. Yang JL, Wang LC, Chang CY, Liu TY. (1999) Singlet oxygen is the major species participating in the induction of DNA strand breakage and 8-hydroxydeoxyguanosine adduct by lead acetate. Environ Mol Mutagen. 1999;33(3):194-201. Yanni AE. (2004) The laboratory rabbit: an animal model of atherosclerosis research. Lab Anim. 2004 Jul;38(3):246-56. Yasutake K, Nakamuta M, Shima Y, Ohyama A, Masuda K, Haruta N, Fujino T, Aoyagi Y, Fukuizumi K, Yoshimoto T, Takemoto R, Miyahara T, Harada N, 180 Hayata F, Nakashima M, Enjoji M. (2009) Nutritional investigation of non-obese patients with non-alcoholic fatty liver disease: the significance of dietary cholesterol. Scand J Gastroenterol. 2009;44(4):471-7. Ye D, Lammers B, Zhao Y, Meurs I, Van Berkel TJ, Van Eck M. (2011) ATP-binding cassette transporters A1 and G1, HDL metabolism, cholesterol efflux, and inflammation: important targets for the treatment of atherosclerosis. Curr Drug Targets. 2011 May;12(5):647-60. Ye P, Cheah I, Halliwell B. (2012) High fat diets and pathology in the guinea pig. Atherosclerosis or liver damage? Biochim Biophys Acta. 2012 Nov 26. doi:10.1016/j.bbadis.2012.11.008 You SA, Wang Q. (2005) Ferritin in atherosclerosis. Clin Chim Acta. 2005 Jul 1;357(1):1-16. Younossi ZM, Gramlich T, Bacon BR, Matteoni CA, Boparai N, O'Neill R, McCullough AJ. (1999) Hepatic iron and nonalcoholic fatty liver disease. Hepatology. 1999 Oct;30(4):847-50. Yu KC, Chen W, Cooper AD. (2001) LDL receptor-related protein mediates cell-surface clustering and hepatic sequestration of chylomicron remnants in LDLR-deficient mice. J Clin Invest. 2001 Jun;107(11):1387-94. Yu M, Romer KA, Nieland TJ, Xu S, Saenz-Vash V, Penman M, Yesilaltay A, Carr SA, Krieger M. (2011) Exoplasmic cysteine Cys384 of the HDL receptor SR-BI is critical for its sensitivity to a small-molecule inhibitor and normal lipid transport activity. Proc Natl Acad Sci U S A. 2011 Jul 26;108(30):12243-8. 181 Yuan XM, Brunk UT. Iron and LDL-oxidation in atherogenesis. APMIS. 1998 Sep;106(9):825-42. Zago MP, Oteiza PI. (2001) The anti-oxidant properties of zinc: interactions with iron and antioxidants. Free Radic Biol Med. 2001 Jul 15;31(2):266-74. Zern TL, West KL, Fernandez ML. (2003) Grape polyphenols decrease plasma triglycerides and cholesterol accumulation in the aorta of ovariectomized guinea pigs. J Nutr. 2003 Jul;133(7):2268-72. Zhang XH, Weissbach H. (2008) Origin and evolution of the protein-repairing enzymes methionine sulphoxide reductases. Biol Rev Camb Philos Soc. 2008 Aug;83(3):249-57. Zhu MJ, Sun LJ, Liu YQ, Feng YL, Tong HT, Hu YH, Zhao Z. (2008) Blood F2-isoprostanes are significantly associated with abnormalities of lipid status in rats with steatosis. World J Gastroenterol. 2008 Aug 7;14(29):4677-83. Zhu H, Santo A, Li Y. (2012) The antioxidant enzyme peroxiredoxin and its protective role in neurological disorders. Exp Biol Med (Maywood). 2012 Feb 1;237(2):143-9. Zhulin IB, Johnson MS, Taylor BL. (1997) How bacteria avoid high oxygen concentrations? Biosci Rep. 1997 Jun;17(3):335-42. 182 [...]... activation induced by iron- induced oxidative stress 28 1.10 Mechanism of iron absorption at intestinal endothelial cells 30 1.11 Control of iron uptake and recycling 33 3.1 Average weight gains of 2-month, 4-month, and 6-month groups 67 3.2 Average saliva cortisol concentrations of animals 69 3.3 TBARS levels of diets at the commencement and the conclusion of the animal study 70 3.4 Total iron contents in the. .. ballooning and cell death, increased inflammation and/ or fibrosis in the liver, eventually progressing to liver cirrhosis and carcinoma (Cohen et al., 2011) Although the relationship between simple hepatic steatosis and NASH remains poorly understood, researchers have widely accepted the “two-hit hypothesis” The first “hit” consists of simple hepatic steatosis which mainly increases the sensitivity of the. .. energy intake and insulin-resistance (Yasutake et al., 2009) Firstly, accumulation of fatty acids could be promoted by excess intake of triglycerides from the diet Secondly, glucose levels could be increased due to excess dietary sugar intake, causing the increase of insulin levels which in turn increases the de novo lipogenesis in liver through activation of ChREBP (for glucose) or SREBP-1c (for insulin)... throughout the life of the person, with or without apparent clinical symptoms Early stages of this disease have even been found in the fetus (Napoli et al., 1997) The impact of cholesterol on the incidence of atherosclerosis is now widely understood A study conducted by Anitchkow and Chalatow in 1913 was one of the earliest studies suggesting this relationship, whereby rabbits fed a diet containing egg... molecules difficult to measure, especially in vivo However, when studying diseases, it is perhaps more meaningful to measure the damage caused by ROS, rather than the ROS themselves Therefore, instead of directly measuring ROS, it is more feasible to measure the end-products of oxidative damage to cellular components in vivo (including DNA, lipids, and proteins) as an estimation of the oxidative stress... liver to secondary insults, while the second “hit” includes oxidative stress, decreased energy production in mitochondria, and inflammation, in which mitochondrial oxidative stress plays a central role (Rolo et al., 2012) When the accumulation of fat in hepatocytes (due to excessive dietary intake of fat or de novo lipogenesis) exceeds the capacity of fat oxidation of mitochondria, the 15 mitochondrial... contributes to the accumulation of fatty acids in the liver 14 Figure 1.5 Diets rich in fat and glucose can lead to hepatic steatosis TG: triglyceride; CM: chylomicron; SREBP-1c: sterol regulatory element binding protein-1c; ChREBP: carbohydrate response element binding protein Simple hepatic steatosis is benign and self-limiting However, some cases of hepatic steatosis may progress further to NASH, which... factors would increase the synthesis of fatty acids in liver which may lead to hepatic steatosis and later hypertriglyceridemia (see Figure 1.4 for an illustration of the pathway) (Baranowski, 2008) Excessive intake of dietary cholesterol could increase the levels of cholesterol oxidation products (or oxysterols), which are the ligands of LXRα and could hence activate the LXRα-SREBP-1c-pathway leading... (Watkins et al., 2011), stroke (Davis et al., 2011), and cerebrovascular disease (Yang et al., 2011) However, the most common manifestation of cardiovascular disease is atherosclerosis, which is characterized by a thickening of the blood vessel wall and often is the primary instigator of other cardiovascular pathology The development of atherosclerosis has been shown to 5 commence even in infancy and. .. cells by packaging triglyceride, cholesterol, 3 and apoB100 and then secreted into the circulation, where they are hydrolyzed by LPL and hepatic lipase (HL) to release fatty acids (Demant et al., 1998) The remnant of VLDL becomes LDL, and is then internalized and utilized by cells expressing LDL-R (including peripheral cells and hepatic cells), which is assisted by an adaptor protein (AP) (Sirinian et al., . CHANGES IN PATHOLOGY AND IRON REGULATION IN GUINEA PIGS IN RELATION TO THE LIPID CONTENT OF THE DIET YE PENG (M. Med, Sichuan Univ., China) A THESIS SUBMITTED FOR THE. in iron and zinc levels in the atherosclerotic plaque, elemental and biochemical changes in the intima during initiation and progression of atherosclerosis over time and cause-consequence relationship. elevated levels of iron promote the formation of atherosclerotic plaques and may contribute to the disease progression, while zinc was found to have a beneficial effect in rabbits. Guinea pigs have