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Phan MAT, Gibson E, Golebiowski B, Stapleton F, Jenner AM, Bucknall MP. Analysis of sex steroids in human tears using LC-MS and GC-MS: Considerations and developments to improve method sensitivity and accuracy. Exp Eye Res 2022; 225:109283. [PMID: 36273577 DOI: 10.1016/j.exer.2022.109283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 10/04/2022] [Accepted: 10/13/2022] [Indexed: 12/29/2022]
Abstract
Sex steroids play a role in regulation of tear film function and may exert their action locally at the ocular surface. However, measurement of sex steroids in tears is difficult due to small-volume tear samples and very low concentrations of the hormones. This short communication highlights what has been achieved to date in the analysis of tear sex steroids using ultra-performance LC-MS (UPLC-MS) as previously published, and reports further and more recent investigations toward optimising mass spectrometry method sensitivity and accuracy. The published UPLC-MS method successfully measured progesterone, androsterone glucuronide and 5α-androstane-3α,17β-diol in pooled basal tears of postmenopausal women, and fourteen sex steroid standards in methanol. Limitations included sub-optimal limits of detection (LOD) and lower limits of quantification (LLOQ) for some analytes (particularly oestrogens), exclusion of sample matrix effects and no use of internal standards. This update reports on further experiments carried out to improve sensitivity and accuracy. Sample matrix effects, internal standard spiking, and derivatisation with dansyl chloride and oximes were investigated. Dansylation significantly improved the LOD and LLOQ of oestrogens and their metabolites, by a factor of 10 for oestradiol and a factor of 5 for oestrone, but sensitivity of this updated method is not sufficient however for analysis of these oestrogens in human tears. Using gas chromatography-mass spectrometry (GC-MS) as an alternative technique to LC-MS, improved sensitivity for derivatised oestradiol is reported. This work demonstrates the need to develop higher sensitivity methods and points researchers towards specific MS ionisation techniques for future analysis of sex steroids in tears, in order to progress current understanding of the role of sex steroids in tear function and dry eye.
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Affiliation(s)
- Minh Anh Thu Phan
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW, 2052, Australia
| | - Emma Gibson
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW, 2052, Australia; Optometry, Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK
| | - Blanka Golebiowski
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW, 2052, Australia.
| | - Fiona Stapleton
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW, 2052, Australia
| | - Andrew M Jenner
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, UNSW, Sydney, NSW, 2052, Australia
| | - Martin P Bucknall
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, NSW, 2052, Australia; Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, UNSW, Sydney, NSW, 2052, Australia
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Phillips GR, Saville JT, Hancock SE, Brown SHJ, Jenner AM, McLean C, Fuller M, Newell KA, Mitchell TW. The long and the short of Huntington’s disease: how the sphingolipid profile is shifted in the caudate of advanced clinical cases. Brain Commun 2021; 4:fcab303. [PMID: 35169703 PMCID: PMC8833324 DOI: 10.1093/braincomms/fcab303] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/27/2021] [Accepted: 12/21/2021] [Indexed: 01/01/2023] Open
Abstract
Huntington’s disease is a devastating neurodegenerative disorder that onsets in late adulthood as progressive and terminal cognitive, psychiatric and motor deficits. The disease is genetic, triggered by a CAG repeat (polyQ) expansion mutation in the Huntingtin gene and resultant huntingtin protein. Although the mutant huntingtin protein is ubiquitously expressed, the striatum degenerates early and consistently in the disease. The polyQ mutation at the N-terminus of the huntingtin protein alters its natural interactions with neural phospholipids in vitro, suggesting that the specific lipid composition of brain regions could influence their vulnerability to interference by mutant huntingtin; however, this has not yet been demonstrated in vivo. Sphingolipids are critical cell signalling molecules, second messengers and membrane components. Despite evidence of sphingolipid disturbance in Huntington’s mouse and cell models, there is limited knowledge of how these lipids are affected in human brain tissue. Using post-mortem brain tissue from five brain regions implicated in Huntington’s disease (control n = 13, Huntington’s n = 13), this study aimed to identify where and how sphingolipid species are affected in the brain of clinically advanced Huntington’s cases. Sphingolipids were extracted from the tissue and analysed using targeted mass spectrometry analysis; proteins were analysed by western blot. The caudate, putamen and cerebellum had distinct sphingolipid changes in Huntington’s brain whilst the white and grey frontal cortex were spared. The caudate of Huntington’s patients had a shifted sphingolipid profile, favouring long (C13–C21) over very-long-chain (C22–C26) ceramides, sphingomyelins and lactosylceramides. Ceramide synthase 1, which synthesizes the long-chain sphingolipids, had a reduced expression in Huntington’s caudate, correlating positively with a younger age at death and a longer CAG repeat length of the Huntington’s patients. The expression of ceramide synthase 2, which synthesizes very-long-chain sphingolipids, was not different in Huntington’s brain. However, there was evidence of possible post-translational modifications in the Huntington’s patients only. Post-translational modifications to ceramide synthase 2 may be driving the distinctive sphingolipid profile shifts of the caudate in advanced Huntington’s disease. This shift in the sphingolipid profile is also found in the most severely affected brain regions of several other neurodegenerative conditions and may be an important feature of region-specific cell dysfunction in neurodegenerative disease.
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Affiliation(s)
- Gabrielle R. Phillips
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Jennifer T. Saville
- Genetics and Molecular Pathology, SA Pathology at Women’s and Children’s Hospital, North Adelaide, SA 5006, Australia
| | - Sarah E. Hancock
- School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Simon H. J. Brown
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
- School of Chemistry and Molecular Biosciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Andrew M. Jenner
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia
| | - Catriona McLean
- Department of Anatomical Pathology, Alfred Health and Florey Neuroscience, Parkville, VIC 3052, Australia
| | - Maria Fuller
- Genetics and Molecular Pathology, SA Pathology at Women’s and Children’s Hospital, North Adelaide, SA 5006, Australia
- Adelaide Medical School, University of Adelaide, Adelaide, SA 5000, Australia
| | - Kelly A. Newell
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Todd W. Mitchell
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
- Molecular Horizons, University of Wollongong, Wollongong, NSW 2522, Australia
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3
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Kreilaus F, Spiro AS, Hannan AJ, Garner B, Jenner AM. Therapeutic Effects of Anthocyanins and Environmental Enrichment in R6/1 Huntington's Disease Mice. J Huntingtons Dis 2017; 5:285-296. [PMID: 27567888 DOI: 10.3233/jhd-160204] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Huntington's disease (HD) is a progressive neurodegenerative disease with no effective treatment or cure. Environmental enrichment has been used to slow processes leading to ageing and neurodegenerative diseases including HD. Phenolic phytochemicals including anthocyanins have also been shown to improve brain function in ageing and neurodegenerative diseases. OBJECTIVE This study examined the effects of anthocyanin dietary supplementation and environmental enrichment on behavioural phenotypes and brain cholesterol metabolic alterations in the R6/1 mouse model of HD. METHODS R6/1 HD mice and their wild-type littermate controls were randomised into the different experimental conditions, involving either environmentally enriched versus standard housing conditions, or anthocyanin versus control diet. Motor dysfunction was assessed from 6 to 26 weeks using the RotaRod and the hind-paw clasping tests. Gas chromatography - tandem mass spectrometry was used to quantify a broad range of sterols in the striatum and cortex of R6/1 HD mice. RESULTS Anthocyanin dietary supplementation delayed the onset of motor dysfunction in female HD mice. Environmental enrichment improved motor function and the hind paw clasping phenotype in male HD mice only. These mice also had lower levels of cholesterol oxidation products in the cortex compared to standard-housed mice. CONCLUSION Both anthocyanin supplementation and environmental enrichment are able to improve the motor dysfunction phenotype of R6/1 mice, however the effectiveness of these interventions was different between the two sexes. The interventions examined did not alter brain cholesterol metabolic deficits that have been reported previously in this mouse model of HD.
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Affiliation(s)
- Fabian Kreilaus
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia.,School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Adena S Spiro
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia.,School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Brett Garner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia.,School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Andrew M Jenner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia.,School of Biological Sciences, University of Wollongong, NSW, Australia
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Kreilaus F, Spiro AS, Hannan AJ, Garner B, Jenner AM. Brain Cholesterol Synthesis and Metabolism is Progressively Disturbed in the R6/1 Mouse Model of Huntington’s Disease: A Targeted GC-MS/MS Sterol Analysis. J Huntingtons Dis 2015; 4:305-18. [DOI: 10.3233/jhd-150170] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Fabian Kreilaus
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Adena S. Spiro
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Anthony J. Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkvillie, VIC, Australia
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Brett Garner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Andrew M. Jenner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia
- School of Biological Sciences, University of Wollongong, NSW, Australia
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Abbott SK, Jenner AM, Spiro AS, Batterham M, Halliday GM, Garner B. Fatty acid composition of the anterior cingulate cortex indicates a high susceptibility to lipid peroxidation in Parkinson's disease. J Parkinsons Dis 2015; 5:175-85. [PMID: 25613350 DOI: 10.3233/jpd-140479] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Oxidative stress contributes to Parkinson's disease (PD) etiology. Although previous studies have focused on sources of free radical formation in brain regions affected by PD, less is known regarding changes in lipid composition and the implications for susceptibility to peroxidation. OBJECTIVE To assess fatty acid profiles from control and PD tissues that are susceptible to PD pathology but devoid of severe destruction. METHODS We used gas chromatography methods to assess fatty acid profiles from control (n = 10) and PD (n = 9) postmortem tissues. We focused on the anterior cingulate cortex (ACC), a region that accumulates alpha-synuclein, but does not undergo severe destruction, and compared this to the occipital cortex, a region that is pathologically spared. RESULTS Our data indicate a significant 33% increase in the proportion of polyunsaturated fatty acids (mol%) present in the PD ACC as compared to control ACC. Increases in highly unsaturated 22:5n-6 and 22:6n-3 fatty acids were particularly pronounced (109% and 73%, respectively). Calculation of a peroxidation index (accounting for total fatty acyl double bounds) indicated a 44% increase in susceptibility of the PD ACC to lipid peroxidation compared to control ACC. Such differences were not detected in the occipital cortex from the same donors. Assessment of F2-isprostane levels confirmed that PD tissue lipids were more oxidized than controls. CONCLUSIONS The global composition of fatty acids in the PD ACC is altered in a way that increases susceptibility to peroxidation in a region-specific manner. This has important implications for PD, supporting the oxidative stress hypothesis of PD pathogenesis.
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Affiliation(s)
- Sarah K Abbott
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Andrew M Jenner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Adena S Spiro
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Marijka Batterham
- National Institute of Applied Statistics Research Australia, University of Wollongong, Wollongong NSW, Australia
| | - Glenda M Halliday
- Neuroscience Research Australia and the University of New South Wales, Sydney, NSW, Australia
| | - Brett Garner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia School of Biological Sciences, University of Wollongong, NSW, Australia
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Kreilaus F, Spiro AS, McLean CA, Garner B, Jenner AM. Evidence for altered cholesterol metabolism in Huntington's disease post mortem brain tissue. Neuropathol Appl Neurobiol 2015; 42:535-46. [PMID: 26373857 DOI: 10.1111/nan.12286] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 09/14/2015] [Indexed: 01/26/2023]
Abstract
AIMS Cholesterol plays an essential role in membrane structure and function, being especially important in the brain. Alteration of brain cholesterol synthesis and metabolism has been demonstrated in several Huntington's disease (HD) mouse and cell models; however, less is known about these alterations in human tissue. This study aimed to identify alterations to cholesterol synthetic and metabolic pathways in human HD brain tissue. METHODS A broad range of cholesterol synthetic precursors, metabolites and oxidation products were measured by gas chromatography-tandem mass spectrometry in five regions of human post mortem HD brain and compared with age- and sex-matched control tissues. The level of enzymes that regulate cholesterol homeostasis, cholesterol 24-hydroxylase and delta(24)-sterol reductase were investigated by Western blotting and qPCR in putamen. RESULTS The most significant changes were localized to the putamen, where a 60% decrease in 24(S)-hydroxycholesterol, 30% increase in cholesterol and 100-200% increase in synthetic precursors (lathosterol, zymosterol and desmosterol) was detected. The enzymes cholesterol 24-hydroxylase and delta(24)-sterol reductase were also significantly decreased in HD putamen as compared with control tissues. Free radical-generated cholesterol oxidation products 7-keto cholesterol and 7β-hydroxycholesterol were also increased by 50-70% in HD putamen. CONCLUSION Human HD brain has significantly decreased cholesterol metabolism and disrupted cholesterol homeostasis. Our data also indicate that lipid oxidative stress accompanies HD pathology.
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Affiliation(s)
- Fabian Kreilaus
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, Australia. .,School of Biological Sciences, University of Wollongong, Wollongong, Australia.
| | - Adena S Spiro
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, Australia.,School of Biological Sciences, University of Wollongong, Wollongong, Australia
| | - Catriona A McLean
- Department of Anatomical Pathology, Alfred Hospital, Prahran, Australia
| | - Brett Garner
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, Australia.,School of Biological Sciences, University of Wollongong, Wollongong, Australia
| | - Andrew M Jenner
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, Australia. .,School of Biological Sciences, University of Wollongong, Wollongong, Australia.
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Cheng D, Spiro AS, Jenner AM, Garner B, Karl T. Long-term cannabidiol treatment prevents the development of social recognition memory deficits in Alzheimer's disease transgenic mice. J Alzheimers Dis 2015; 42:1383-96. [PMID: 25024347 DOI: 10.3233/jad-140921] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Impairments in cognitive ability and widespread pathophysiological changes caused by neurotoxicity, neuroinflammation, oxidative damage, and altered cholesterol homeostasis are associated with Alzheimer's disease (AD). Cannabidiol (CBD) has been shown to reverse cognitive deficits of AD transgenic mice and to exert neuroprotective, anti-oxidative, and anti-inflammatory properties in vitro and in vivo. Here we evaluate the preventative properties of long-term CBD treatment in male AβPPSwe/PS1ΔE9 (AβPP × PS1) mice, a transgenic model of AD. Control and AD transgenic mice were treated orally from 2.5 months of age with CBD (20 mg/kg) daily for 8 months. Mice were then assessed in the social preference test, elevated plus maze, and fear conditioning paradigms, before cortical and hippocampal tissues were analyzed for amyloid load, oxidative damage, cholesterol, phytosterols, and inflammation. We found that AβPP × PS1 mice developed a social recognition deficit, which was prevented by CBD treatment. CBD had no impact on anxiety or associative learning. The prevention of the social recognition deficit was not associated with any changes in amyloid load or oxidative damage. However, the study revealed a subtle impact of CBD on neuroinflammation, cholesterol, and dietary phytosterol retention, which deserves further investigation. This study is the first to demonstrate CBD's ability to prevent the development of a social recognition deficit in AD transgenic mice. Our findings provide the first evidence that CBD may have potential as a preventative treatment for AD with a particular relevance for symptoms of social withdrawal and facial recognition.
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Affiliation(s)
- David Cheng
- Neuroscience Research Australia, Randwick, NSW, Australia School of Medical Sciences, University of New South Wales, NSW, Australia
| | - Adena S Spiro
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Andrew M Jenner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Brett Garner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Tim Karl
- Neuroscience Research Australia, Randwick, NSW, Australia School of Medical Sciences, University of New South Wales, NSW, Australia Schizophrenia Research Institute, Darlinghurst, NSW, Australia
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Li H, Ruberu K, Muñoz SS, Jenner AM, Spiro A, Zhao H, Rassart E, Sanchez D, Ganfornina MD, Karl T, Garner B. Apolipoprotein D modulates amyloid pathology in APP/PS1 Alzheimer's disease mice. Neurobiol Aging 2015; 36:1820-33. [PMID: 25784209 DOI: 10.1016/j.neurobiolaging.2015.02.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/22/2015] [Accepted: 02/10/2015] [Indexed: 11/24/2022]
Abstract
Apolipoprotein D (apoD) is expressed in the brain and levels are increased in affected brain regions in Alzheimer's disease (AD). The role that apoD may play in regulating AD pathology has not been addressed. Here, we crossed both apoD-null mice and Thy-1 human apoD transgenic mice with APP-PS1 amyloidogenic AD mice. Loss of apoD resulted in a nearly 2-fold increase in hippocampal amyloid plaque load, as assessed by immunohistochemical staining. Conversely, transgenic expression of neuronal apoD reduced hippocampal plaque load by approximately 35%. This latter finding was associated with a 60% decrease in amyloid β 1-40 peptide levels, and a 34% decrease in insoluble amyloid β 1-42 peptide. Assessment of β-site amyloid precursor protein cleaving enzyme-1 (BACE1) levels and proteolytic products of amyloid precursor protein and neuregulin-1 point toward a possible association of altered BACE1 activity in association with altered apoD levels. In conclusion, the current studies provide clear evidence that apoD regulates amyloid plaque pathology in a mouse model of AD.
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Affiliation(s)
- Hongyun Li
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Kalani Ruberu
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Sonia Sanz Muñoz
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Andrew M Jenner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Adena Spiro
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Hua Zhao
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; School of Biological Sciences, University of Wollongong, NSW, Australia
| | - Eric Rassart
- Laboratoire de biologie moléculaire, Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Canada; BioMed, centre de recherches biomédicales, Université du Québec à Montréal, Montréal, Canada
| | - Diego Sanchez
- Departamento de Bioquímica y Biología Molecular y Fisiología - Instituto de Biología y Genética Molecular, Universidad de Valladolid - CSIC, Valladolid, Spain
| | - Maria D Ganfornina
- Departamento de Bioquímica y Biología Molecular y Fisiología - Instituto de Biología y Genética Molecular, Universidad de Valladolid - CSIC, Valladolid, Spain
| | - Tim Karl
- Neuroscience Research Australia, Randwick, NSW, Australia; School of Medical Sciences, University of New South Wales, NSW, Australia; Schizophrenia Research Institute, Darlinghurst, NSW, Australia
| | - Brett Garner
- Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia; School of Biological Sciences, University of Wollongong, NSW, Australia.
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Bhatia S, Jenner AM, Li H, Ruberu K, Spiro AS, Shepherd CE, Kril JJ, Kain N, Don A, Garner B. Increased apolipoprotein D dimer formation in Alzheimer's disease hippocampus is associated with lipid conjugated diene levels. J Alzheimers Dis 2013; 35:475-86. [PMID: 23455990 DOI: 10.3233/jad-122278] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Previous studies indicate that apolipoprotein D (apoD) may have a lipid antioxidant function in the brain. We have shown that apoD can reduce free radical-generating lipid hydroperoxides to inert lipid hydroxides in a reaction that involves conversion of surface exposed apoD methione-93 (Met93) residue to Met93-sulfoxide (Met93-SO). One consequence of this reaction is the formation of a stable dimerized form of apoD. As cerebral lipid peroxidation is associated with Alzheimer's disease (AD), in the present study we aimed to assess the possible presence of apoD dimers in postmortem hippocampal and cerebellar tissues derived from a cohort of pathologically defined cases ranging from control to late stage AD. Both soluble and insoluble (requiring guanidine HCl extraction) fractions of tissue homogenates were analyzed for apoD and its dimerized form. We also assessed amyloid-β levels by ELISA and levels of lipid peroxidation by lipid conjugated diene and F2-isoprostane analysis. Our studies reveal a significant association between soluble apoD levels and AD Braak stage whereas apoD dimer formation appears to increase predominantly in the advanced stages of disease. The formation of apoD dimers is closely correlated to lipid conjugated diene levels and occurs in the hippocampus but not in the cerebellum. These results are consistent with the hypothesis that apoD acts as a lipid antioxidant in the brain.
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Affiliation(s)
- Surabhi Bhatia
- Neuroscience Research Australia, Randwick, NSW, Australia
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Jovanović V, Abdul Aziz N, Lim YT, Ng Ai Poh A, Jin Hui Chan S, Ho Xin Pei E, Lew FC, Shui G, Jenner AM, Bowen L, McKinney EF, Lyons PA, Kemeny MD, Smith KGC, Wenk MR, MacAry PA. Lipid anti-lipid antibody responses correlate with disease activity in systemic lupus erythematosus. PLoS One 2013; 8:e55639. [PMID: 23409013 PMCID: PMC3567138 DOI: 10.1371/journal.pone.0055639] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 12/28/2012] [Indexed: 12/17/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by broad clinical manifestations including cardiovascular and renal complications with periodic disease flares and significant morbidity and mortality. One of the main contributing factors to the pathology of SLE is the accumulation and impaired clearance of immune complexes of which the principle components are host auto-antigens and antibodies. The contribution of host lipids to the formation of these autoimmune complexes remains poorly defined. The aim of the present study was to identify and analyze candidate lipid autoantigens and their corresponding anti-lipid antibody responses in a well-defined SLE patient cohort using a combination of immunological and biophysical techniques. Disease monitoring in the SLE cohort was undertaken with serial British Isles Lupus Assessment Group (BILAG) scoring. Correlations between specific lipid/anti-lipid responses were investigated as disease activity developed from active flares to quiescent during a follow up period. We report a significant negative correlation between anti-lipid antibodies for 24S-hydroxycholesterol, cardiolipin and phosphatidylserine with SLE disease activity. Taken together, these data suggest that lipid autoantigens represent a new family of biomarkers that can be employed to monitor disease activity plus the efficacy of therapeutic intervention in SLE.
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Affiliation(s)
- Vojislav Jovanović
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Nurhuda Abdul Aziz
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Yan Ting Lim
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Amanda Ng Ai Poh
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Sherlynn Jin Hui Chan
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Eliza Ho Xin Pei
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Fei Chuin Lew
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Guanghou Shui
- Department of Biochemistry, National University of Singapore, Singapore
| | - Andrew M. Jenner
- School of Biological Sciences, Illawara Health and Medical Research Institute, University of Wollongong, Australia
| | - Li Bowen
- Department of Biochemistry, National University of Singapore, Singapore
| | - Eoin F. McKinney
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, School of Clinical Medicine, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Paul A. Lyons
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, School of Clinical Medicine, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Michael D. Kemeny
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
| | - Kenneth G. C. Smith
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, School of Clinical Medicine, Addenbrooke’s Hospital, Cambridge, United Kingdom
| | - Markus R. Wenk
- Department of Biochemistry, National University of Singapore, Singapore
| | - Paul A. MacAry
- Immunology Programme and Department of Microbiology, National University of Singapore, Singapore
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11
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Wong YT, Gruber J, Jenner AM, Tay FEH, Ruan R. Chronic resveratrol intake reverses pro-inflammatory cytokine profile and oxidative DNA damage in ageing hybrid mice. Age (Dordr) 2011; 33:229-246. [PMID: 20730501 PMCID: PMC3168607 DOI: 10.1007/s11357-010-9174-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 08/03/2010] [Indexed: 05/29/2023]
Abstract
Thymic involution and shrinkage of secondary lymphoid organs are leading causes of the deterioration of the T-cell compartment with age. Inflamm-aging, a sustained inflammatory status, has been associated with chronic diseases and shortened longevity. This is the first study to investigate the effect of treating aging hybrid mice with long-term, low-dose resveratrol (RSV) in drinking water by assessing multiple immunological markers and profiles in the immune system. We found that hybrid mice exhibited marked age-related changes in the CD3+CD4+, C3+CD8+, CD4+CD25+, CD4M and CD8M surface markers. RSV reversed surface phenotypes of old mice to that of young mice by maintaining the CD4+ and CD8+ population in splenocytes as well as reducing CD8+CD44+ (CD8M) cells in the aged. RSV also enhanced the CD4+CD25+ population in old mice. Interestingly, pro-inflammatory status in young mice was transiently elevated by RSV but it consequently mitigated the age-dependent increased pro-inflammatory cytokine profile while preserving the anti-inflammatory cytokine condition in the old mice. Age-dependent increase in 8OHdG, an oxidative DNA damage marker was ameliorated by RSV. Immunological-focused microarray gene expression analysis showed that only the CD72 gene was significantly downregulated in the 12-month RSV-treated mice compared to age-matched controls. Our study indicates that RSV even at low physiological relevant levels is able to affect the immune system without causing marked gene expression changes.
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Affiliation(s)
- Yee Ting Wong
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, #04-01, The Nanos, Singapore, Singapore 138669
- Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore
| | - Jan Gruber
- Neurobiology and Ageing Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Andrew M. Jenner
- Neurobiology and Ageing Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Francis Eng Hock Tay
- Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore
- Medical Devices Research Group, Institute of Bioengineering and Nanotechnology, Singapore, Singapore
| | - Runsheng Ruan
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, #04-01, The Nanos, Singapore, Singapore 138669
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12
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Lim L, Jackson-Lewis V, Wong LC, Shui GH, Goh AXH, Kesavapany S, Jenner AM, Fivaz M, Przedborski S, Wenk MR. Lanosterol induces mitochondrial uncoupling and protects dopaminergic neurons from cell death in a model for Parkinson's disease. Cell Death Differ 2011; 19:416-27. [PMID: 21818119 PMCID: PMC3278725 DOI: 10.1038/cdd.2011.105] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder marked by the selective degeneration of dopaminergic neurons in the nigrostriatal pathway. Several lines of evidence indicate that mitochondrial dysfunction contributes to its etiology. Other studies have suggested that alterations in sterol homeostasis correlate with increased risk for PD. Whether these observations are functionally related is, however, unknown. In this study, we used a toxin-induced mouse model of PD and measured levels of nine sterol intermediates. We found that lanosterol is significantly (∼50%) and specifically reduced in the nigrostriatal regions of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice, indicative of altered lanosterol metabolism during PD pathogenesis. Remarkably, exogenous addition of lanosterol rescued dopaminergic neurons from 1-methyl-4-phenylpyridinium (MPP+)-induced cell death in culture. Furthermore, we observed a marked redistribution of lanosterol synthase from the endoplasmic reticulum to mitochondria in dopaminergic neurons exposed to MPP+, suggesting that lanosterol might exert its survival effect by regulating mitochondrial function. Consistent with this model, we find that lanosterol induces mild depolarization of mitochondria and promotes autophagy. Collectively, our results highlight a novel sterol-based neuroprotective mechanism with direct relevance to PD.
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Affiliation(s)
- L Lim
- Department of Biological Sciences, National University of Singapore, Singapore.
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13
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Kim JH, Ee SM, Jittiwat J, Ong ES, Farooqui AA, Jenner AM, Ong WY. Increased expression of acyl-coenzyme A: cholesterol acyltransferase-1 and elevated cholesteryl esters in the hippocampus after excitotoxic injury. Neuroscience 2011; 185:125-34. [PMID: 21514367 DOI: 10.1016/j.neuroscience.2011.04.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 04/05/2011] [Accepted: 04/08/2011] [Indexed: 10/18/2022]
Abstract
Significant increases in levels of cholesterol and cholesterol oxidation products are detected in the hippocampus undergoing degeneration after excitotoxicity induced by the potent glutamate analog, kainate (KA), but until now, it is unclear whether the cholesterol is in the free or esterified form. The present study was carried out to examine the expression of the enzyme involved in cholesteryl ester biosynthesis, acyl-coenzyme A: cholesterol acyltransferase (ACAT) and cholesteryl esters after KA excitotoxicity. A 1000-fold greater basal mRNA level of ACAT1 than ACAT2 was detected in the normal brain. ACAT1 mRNA and protein were upregulated in the hippocampus at 1 and 2 weeks after KA injections, at a time of glial reaction. Immunohistochemistry showed ACAT1 labeling of oligodendrocytes in the white matter and axon terminals in hippocampal CA fields of normal rats, and loss of staining in neurons but increased immunoreactivity of oligodendrocytes, in areas affected by KA. Gas chromatography-mass spectrometry analyses confirmed previous observations of a marked increase in level of total cholesterol and cholesterol oxidation products, whilst nuclear magnetic resonance spectroscopy showed significant increases in cholesteryl ester species in the degenerating hippocampus. Upregulation of ACAT1 expression was detected in OLN93 oligodendrocytes after KA treatment, and increased expression was prevented by an antioxidant or free radical scavenger in vitro. This suggests that ACAT1 expression may be induced by oxidative stress. Together, our results show elevated ACAT1 expression and increased cholesteryl esters after KA excitotoxicity. Further studies are necessary to determine a possible role of ACAT1 in acute and chronic neurodegenerative diseases.
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Affiliation(s)
- J-H Kim
- Department of Anatomy, National University of Singapore, Singapore 119260
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14
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Cheng D, Jenner AM, Shui G, Cheong WF, Mitchell TW, Nealon JR, Kim WS, McCann H, Wenk MR, Halliday GM, Garner B. Lipid pathway alterations in Parkinson's disease primary visual cortex. PLoS One 2011; 6:e17299. [PMID: 21387008 PMCID: PMC3046155 DOI: 10.1371/journal.pone.0017299] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 01/28/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND We present a lipidomics analysis of human Parkinson's disease tissues. We have focused on the primary visual cortex, a region that is devoid of pathological changes and Lewy bodies; and two additional regions, the amygdala and anterior cingulate cortex which contain Lewy bodies at different disease stages but do not have as severe degeneration as the substantia nigra. METHODOLOGY/PRINCIPAL FINDINGS Using liquid chromatography mass spectrometry lipidomics techniques for an initial screen of 200 lipid species, significant changes in 79 sphingolipid, glycerophospholipid and cholesterol species were detected in the visual cortex of Parkinson's disease patients (n = 10) compared to controls (n = 10) as assessed by two-sided unpaired t-test (p-value <0.05). False discovery rate analysis confirmed that 73 of these 79 lipid species were significantly changed in the visual cortex (q-value <0.05). By contrast, changes in 17 and 12 lipid species were identified in the Parkinson's disease amygdala and anterior cingulate cortex, respectively, compared to controls; none of which remained significant after false discovery rate analysis. Using gas chromatography mass spectrometry techniques, 6 out of 7 oxysterols analysed from both non-enzymatic and enzymatic pathways were also selectively increased in the Parkinson's disease visual cortex. Many of these changes in visual cortex lipids were correlated with relevant changes in the expression of genes involved in lipid metabolism and an oxidative stress response as determined by quantitative polymerase chain reaction techniques. CONCLUSIONS/SIGNIFICANCE The data indicate that changes in lipid metabolism occur in the Parkinson's disease visual cortex in the absence of obvious pathology. This suggests that normalization of lipid metabolism and/or oxidative stress status in the visual cortex may represent a novel route for treatment of non-motor symptoms, such as visual hallucinations, that are experienced by a majority of Parkinson's disease patients.
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Affiliation(s)
- Danni Cheng
- Neuroscience Research Australia, Sydney, New South Wales, Australia
| | - Andrew M. Jenner
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Guanghou Shui
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
- Life Science Institute, National University of Singapore, Singapore, Singapore
| | - Wei Fun Cheong
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Todd W. Mitchell
- School of Health Sciences, University of Wollongong, Wollongong, New South Wales, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia
| | - Jessica R. Nealon
- School of Chemistry, University of Wollongong, Wollongong, New South Wales, Australia
| | - Woojin S. Kim
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Heather McCann
- Neuroscience Research Australia, Sydney, New South Wales, Australia
| | - Markus R. Wenk
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Glenda M. Halliday
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Brett Garner
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
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15
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Choy MS, Chen MJ, Manikandan J, Peng ZF, Jenner AM, Melendez AJ, Cheung NS. Up-regulation of endoplasmic reticulum stress-related genes during the early phase of treatment of cultured cortical neurons by the proteasomal inhibitor lactacystin. J Cell Physiol 2011; 226:494-510. [PMID: 20683911 DOI: 10.1002/jcp.22359] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Inhibition of proteasome degradation pathway has been implicated in neuronal cell death leading to neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. We and others demonstrated that treatment of cortical neurons with the proteasomal inhibitor lactacystin leads to apoptosis. We discovered by microarray analysis that lactacystin treatment modulates the expression of both potentially neuroprotective as well as pro-apoptotic genes in neurons. However, the significance of the genes which upon transcriptional modulation contributed to proteasomal inhibition-induced apoptosis, remained unidentified. By employing microarray analysis to decipher the time-dependent changes in transcription of these genes in cultured cortical neurons, we discovered different groups of genes were transcriptionally regulated in the early and late phase of lactacystin-induced cell death. In the early phase, several neuroprotective genes such as those encoding the proteasome subunits and ubiquitin-associated enzymes, as well as the heat-shock proteins (HSP) were up-regulated. However, the pro-apoptotic endoplasmic reticulum (ER) stress-associated genes were also up-regulated at the early phase of lactacystin-induced neuronal cell death. In the late phase, genes encoding antioxidants and calcium-binding proteins were up-regulated while those associated with cholesterol biosynthesis were down-regulated. The data suggest that ER stress may participate in mediating the apoptotic responses induced by proteasomal inhibition. The up-regulation of the neuroprotective antioxidant genes and calcium-binding protein genes and down-regulation of the cholesterol biosynthesis genes in the later phase are likely consequences of stimulation of the pro-apoptotic signaling pathways in the early phase of lactacystin treatment.
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Affiliation(s)
- Meng Shyan Choy
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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16
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Jenner AM, Lim WLF, Ng MPE, Wenk MR, Shui G, Sharman MJ, Gandy SE, Martins RN. The effect of APOE genotype on brain levels of oxysterols in young and old human APOE epsilon2, epsilon3 and epsilon4 knock-in mice. Neuroscience 2010; 169:109-15. [PMID: 20416362 DOI: 10.1016/j.neuroscience.2010.04.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 04/04/2010] [Accepted: 04/14/2010] [Indexed: 11/19/2022]
Abstract
Despite apolipoprotein E's important role in cholesterol transport and metabolism in the brain as well as its influence on Alzheimer's disease, the impact of the human APOE genotype on cholesterol metabolism in brain has not been fully examined. This study was carried out to investigate APOE genotype effects on oxysterols measured. In this study the measurement of cholesterol and several oxysterols in the brains of human APOE epsilon2, epsilon3 and epsilon4 knock-in mice at 8 weeks and 1 year of age using gas chromatography mass spectrometry (GC-MS) demonstrated no APOE genotype or age effect on total brain cholesterol and the oxysterol 24-hydroxycholesterol. The level of 27-hydroxycholesterol was elevated in 1 year old animals for all APOE genotypes. Interestingly, lathosterol an indicator of cholesterol synthesis was significantly reduced in the 1 year old animals for all APOE genotypes. APOE epsilon4 expressing mice exhibited statistically lower levels of lathosterol compared to APOE epsilon2 in both the young and old mice. Oxidized cholesterol metabolites were significantly lower in APOE epsilon2 mice compared to other genotypes at 8 weeks old. Although minimal differences were observed between APOE E3 and E4 knock-in (KI) mice, these findings indicate that there are some clear APOE genotype specific effects on brain cholesterol synthesis and associated metabolic pathways, particularly in APOE epsilon2 KI mice.
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Affiliation(s)
- A M Jenner
- Neurobiology and Ageing Research Program, Centre for Life Sciences, Yong Loo Lin School of Medicine, National University of Singapore, 28 Medical Drive, Singapore 117456
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17
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Ong WY, Kim JH, He X, Chen P, Farooqui AA, Jenner AM. Changes in brain cholesterol metabolome after excitotoxicity. Mol Neurobiol 2010; 41:299-313. [PMID: 20140539 DOI: 10.1007/s12035-010-8099-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 01/07/2010] [Indexed: 12/15/2022]
Abstract
Excitotoxicity due to excess stimulation of glutamate receptors in neurons is accompanied by increased Ca(2+) influx, stimulation of Ca(2+)-dependent enzymes, ATP depletion, increase in lipid peroxidation products, and loss of glutathione. These changes resemble neurochemical alterations in acute neuronal injury (stroke, spinal cord injury, and traumatic brain injury) and chronic neurodegenerative diseases such as Alzheimer's disease. Intracerebroventricular injection of the potent glutamate analog kainate in rats results in increased cholesterol concentration in the hippocampus at short to medium time intervals, i.e., 3 days-1 week post-injection, as detected by gas chromatography-mass spectrometry in the lesioned hippocampus. This is accompanied by an early increase in levels of cholesterol biosynthetic precursors and increases in both enzymatically derived oxysterols such as 24-hydroxycholesterol and cholesterol oxidation products (COPs) generated by reactive oxygen species, including cholesterol epoxides and 7-ketocholesterol. In contrast to COPs, no change in concentration of the neurosteroid pregnenolone was found after KA injury. Cholesterol and COPs significantly increase exocytosis in cultured PC12 cells and neurons, and both oxysterols and COPs are able to induce cytotoxic and apoptotic injuries in different cell types, including neurons. Together, the findings suggest that increased cholesterol and COPs after KA excitotoxicity could themselves lead to disturbed neuronal ion homeostasis, increased neurotransmitter release, and propagation of excitotoxicity.
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Affiliation(s)
- Wei-Yi Ong
- Department of Anatomy, National University of Singapore, Singapore, 119260, Singapore.
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18
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Loke WM, Jenner AM, Proudfoot JM, McKinley AJ, Hodgson JM, Halliwell B, Croft KD. A metabolite profiling approach to identify biomarkers of flavonoid intake in humans. J Nutr 2009; 139:2309-14. [PMID: 19812218 DOI: 10.3945/jn.109.113613] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Flavonoids are phytochemicals that are widespread in the human diet. Despite limitations in their bioavailability, experimental and epidemiological data suggest health benefits of flavonoid consumption. Valid biomarkers of flavonoid intake may be useful for estimating exposure in a range of settings. However, to date, few useful flavonoid biomarkers have been identified. In this study, we used a metabolite profiling approach to examine the aromatic and phenolic profile of plasma and urine of healthy men after oral consumption of 200 mg of the pure flavonoids, quercetin, (-)-epicatechin, and epigallocatechin gallate, which represent major flavonoid constituents in the diet. Following enzymatic hydrolysis, 71 aromatic compounds were quantified in plasma and urine at 2 and 5 h, respectively, after flavonoid ingestion. Plasma concentrations of different aromatic compounds ranged widely, from 0.01 to 10 micromol/L, with variation among volunteers. None of the aromatic compounds was significantly elevated in plasma 2 h after consumption of either flavonoid compared with water placebo. This indicates that flavonoid-derived aromatic compounds are not responsible for the acute physiological effects reported within 2 h in previous human intervention studies involving flavonoids or flavonoid-rich food consumption. These effects are more likely due to absorption of the intact flavonoid. Our urine analysis suggested that urinary 4-ethylphenol, benzoic acid, and 4-ethylbenzoic acid may be potential biomarkers of quercetin intake and 1,3,5-trimethoxybenzene, 4-O-methylgallic acid, 3-O-methylgallic acid, and gallic acid may be potential markers of epigallocatechin gallate intake. Potential biomarkers of (-)-epicatechin were not identified. These urinary biomarkers may provide an accurate indication of flavonoid exposure.
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Affiliation(s)
- Wai Mun Loke
- School of Medicine and Pharmacology, University of Western Australia, Royal Perth Hospital Unit, Perth, WA 6000, Australia
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19
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Abstract
The present study was carried out to elucidate changes in the gene expression and activity of cholesterol biosynthetic enzymes and transporters in the rat hippocampus after kainate excitotoxicity. Significantly increased cholesterol level was detected in the degenerating hippocampus, reaching double normal levels at 1 week after kainate injury. RT-PCR analyses of hippocampal homogenates showed significantly decreased mRNA expression of the transcription factor controlling cholesterol biosynthesis SREBP-2, and the rate-controlling enzyme HMG-CoA (3-hydroxy-3-methyl-glutaryl-CoA) reductase at all time points after kainate injection; and decreased lanosterol synthase and CYP51 at 1 and 2 weeks post-kainate injection respectively. GC-MS analyses showed a significant increase in cholesterol biosynthetic precursors lanosterol, desmosterol and 7-dehydrocholesterol at 1 day after kainate injection presumably reflecting biosysnthesis in injured neurons, and significant decreases in precursors at 1 and 2 weeks post-kainate injection, at time of gliosis in the degenerating hippocampus. Levels of cholesterol autooxidation including 7 ketocholesterol and cholesterol epoxides were elevated in the kainate lesioned hippocampus. Furthermore, loss of expression of the cholesterol transporter, ABCA1 was detected in neurons, but increased expression in astrocytes was detected after kainate lesions. The results suggest that increased cholesterol biosynthesis and loss of ABCA1 expression in injured neurons might result in increase in cholesterol in the degenerating hippocampus. The increased cholesterol might predispose to increased formation of cholesterol oxidation products which have been shown to be toxic to neurons.
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Affiliation(s)
- Ji-Hyun Kim
- Department of Anatomy, National University of Singapore, Singapore
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20
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Gruber J, Tang SY, Jenner AM, Mudway I, Blomberg A, Behndig A, Kasiman K, Lee CYJ, Seet RCS, Zhang W, Chen C, Kelly FJ, Halliwell B. Allantoin in human plasma, serum, and nasal-lining fluids as a biomarker of oxidative stress: avoiding artifacts and establishing real in vivo concentrations. Antioxid Redox Signal 2009; 11:1767-76. [PMID: 19388825 DOI: 10.1089/ars.2008.2364] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Urate is the terminal product of purine metabolism in primates, including humans. Urate is also an efficient scavenger of oxidizing species and is thought to be an important antioxidant in human body fluids. Allantoin, the major oxidation product of urate, has been suggested as a candidate biomarker of oxidative stress because it is not produced metabolically. Although urate is converted to allantoin under strongly alkaline pH, such conditions have been used in the past to facilitate extraction of allantoin. We evolved a method for the determination of allantoin concentrations in human plasma and serum by gas chromatography-mass spectrometry without such artifact. With this method, we show that alkaline conditions do indeed cause breakdown of urate, leading to significant overestimation of allantoin concentration in human samples. By using our alternative method, serum samples from 98 volunteers were analyzed, and allantoin levels were found to be significantly lower than was previously reported. The in vivo utility and sensitivity of our method was further evaluated in human nasal-lining fluids. We were able to demonstrate an ozone-induced increase in allantoin, in the absence of increases in either ascorbate or glutathione oxidation products.
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Affiliation(s)
- Jan Gruber
- Centre for Life Sciences, Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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21
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Ong WY, Jenner AM, Pan N, Ong CN, Halliwell B. Elevated oxidative stress, iron accumulation around microvessels and increased 4-hydroxynonenal immunostaining in zone 1 of the liver acinus in hypercholesterolemic rabbits. Free Radic Res 2009; 43:241-9. [DOI: 10.1080/10715760802691455] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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He X, Jittiwat J, Kim JH, Jenner AM, Farooqui AA, Patel SC, Ong WY. Apolipoprotein D modulates F2-isoprostane and 7-ketocholesterol formation and has a neuroprotective effect on organotypic hippocampal cultures after kainate-induced excitotoxic injury. Neurosci Lett 2009; 455:183-6. [PMID: 19429117 PMCID: PMC7117013 DOI: 10.1016/j.neulet.2009.03.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Revised: 02/24/2009] [Accepted: 03/09/2009] [Indexed: 11/26/2022]
Abstract
Apolipoprotein D (apoD), a member of the lipocalin family of transporter proteins binds a number of small lipophilic molecules including arachidonic acid and cholesterol. Recent studies showed a protective function of mammalian apoD as well as its insect and plant homologs against oxidative stress. In this study we investigated the effect of direct addition of exogenous human apoD protein purified from breast cystic fluid to rat hippocampal slice cultures after excitotoxic injury induced by the glutamate analog kainate. ApoD at a concentration of 10 microg/ml partially prevented loss of MAP2 immunostaining and LDH release from injured hippocampal neurons after kainate injury. ApoD also attenuated the increase in oxidative products of arachidonic acid and cholesterol, F(2)-isoprostanes and 7-ketocholesterol, respectively, after kainate treatment. In view of the molecular structure of apoD which consists of an eight stranded beta barrel that forms a binding pocket for a number of small hydrophobic molecules, we propose that apoD promotes its neuroprotective effects by binding to arachidonic acid and cholesterol thus preventing their oxidation to neurotoxic products such as 4-hydroxynonenal (4-HNE) and 7-ketocholesterol.
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Affiliation(s)
- Xin He
- Department of Anatomy, Beijing University of Chinese Medicine, Beijing 100029, China
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23
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Wong YT, Gruber J, Jenner AM, Ng MPE, Ruan R, Tay FEH. Elevation of oxidative-damage biomarkers during aging in F2 hybrid mice: protection by chronic oral intake of resveratrol. Free Radic Biol Med 2009; 46:799-809. [PMID: 19159678 DOI: 10.1016/j.freeradbiomed.2008.12.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 12/07/2008] [Accepted: 12/09/2008] [Indexed: 10/21/2022]
Abstract
Resveratrol (RSV), a naturally occurring phytoalexin that can be found in red wine, berries, and peanuts, has been shown to extend both mean and maximum life span in model organisms. RSV has also been reported to shift the physiology of middle-aged mice on a high-calorie diet toward that of mice on a standard diet. These beneficial effects of RSV have been suggested to resemble caloric restriction. Our study in F2 four-way cross-hybrid mice was the first to evaluate the effects of aging and long-term RSV treatment (14.09+/-3.4 mg/L in drinking water for 6 or 12 months) on biomarkers of oxidative damage to DNA, 8-hydroxy-2'-deoxyguanosine (8OHdG); lipid, 8-iso-prostaglandin(2 alpha) (8-iso-PGF(2 alpha)); and protein, protein carbonyl content (PCC). There was a significant age-dependent accumulation of oxidative damage to DNA, lipid, and protein as well as a clear increase in urine 8-iso-PGF(2 alpha) levels in the majority of mouse tissues. Rates of age-dependent increases in damage biomarkers varied between tissues. Chronic RSV treatment elevated total RSV plasma levels and reduced the observed age-dependent accumulation of (1) 8OHdG in liver and heart, (2) 8-iso-PGF(2 alpha) in heart and urine, and (3) PCC in liver and kidney. However, a 12-month RSV intake resulted in significant elevation of 8-iso-PGF(2 alpha) and PCC in kidney. Our studies demonstrate that RSV treatment consistently attenuated oxidative damage in tissues where age-related oxidative damage accumulation was prominent, but also suggested that chronic RSV treatment may induce nephrotoxicity.
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Affiliation(s)
- Yee Ting Wong
- Cancer and Ageing Research Group, Institute of Bioengineering and Nanotechnology, Singapore
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24
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Lee CYJ, Huang SH, Jenner AM, Halliwell B. Measurement of F2-isoprostanes, hydroxyeicosatetraenoic products, and oxysterols from a single plasma sample. Free Radic Biol Med 2008; 44:1314-22. [PMID: 18226605 DOI: 10.1016/j.freeradbiomed.2007.12.026] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 11/24/2007] [Accepted: 12/10/2007] [Indexed: 11/15/2022]
Abstract
Oxidized lipids such as F2-isoprostanes (F2-IsoPs), hydroxyeicosatetraenoic acid products (HETEs), and cholesterol oxidation products (COPs) are widely believed to be involved in multiple diseases. Usually, each product is measured individually in separate blood samples. In this study we describe a method allowing us to measure F2-IsoPs, HETEs, COPs, and arachidonate using a single sample. Plasma (1 ml) samples from healthy volunteers were diluted with heavy isotopic standards, hydrolyzed in alkali with organic solvent, and then subjected to anionic-exchange solid-phase extraction (SPE). After the SPE column was washed, hexane and hexane/ethyl acetate portions were collected and combined for COPs measurement. Thereafter the column was loaded with hexane/ethanol/acetic acid and fractions were collected for total F2-IsoPs, total HETEs, and arachidonate measurement. All compounds in the eluates were measured by gas chromatography-mass spectrometry. The efficiency of SPE and reproducibility for all compounds measured were high. Levels of total F2-IsoPs (0.45+/-0.26 ng/ml (n=157)), total HETEs (34.06+/-16.35 ng/ml (n=21)), total arachidonate (68.36+/-24.45 microg/ml (n=33)), and COPs (7-ketocholesterol, 12.25+/-6.56 ng/ml; 7beta-hydroxycholesterol, 6.32+/-3.46 ng/ml; 7alpha-hydroxycholesterol, 15.06+/-7.06 ng/ml; 24-hydroxycholesterol, 41.39+/-18.22 ng/ml; and 27-hydroxycholesterol, 29.08+/-16.79 ng/ml (n=26)) were recorded in healthy subjects (age range 20 to 66 years; average male to female ratio 1:1).
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Affiliation(s)
- Chung-Yung J Lee
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597
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25
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Abstract
Soy sauce is a traditional fermented seasoning in Asian countries, that has high antioxidant activity in vitro and some antioxidant activity in vivo. We attempted to identify the major antioxidants present, using the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay as a guide. 3-Hydroxy-2-methyl-4H-pyran-4-one (maltol) was one of several active compounds found in an ethyl acetate extract of dark soy sauce (DSS) and was present at millimolar concentrations in DSS. However, most of the antioxidant activity was present in colored fractions, two of which (CP1 and CP2) were obtained by gel filtration chromatography. Their structural characteristics based on nuclear magnetic resonance (NMR) and electrospray-ionization time-of-flight mass spectrometry (ESI-TOF-MS) analysis suggest that carbohydrate-containing pigments such as melanoidins are the major contributors to the high antioxidant capacity of DSS.
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Affiliation(s)
- Huansong Wang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, 117597 Singapore
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26
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Lee HC, Jenner AM, Low CS, Lee YK. Effect of tea phenolics and their aromatic fecal bacterial metabolites on intestinal microbiota. Res Microbiol 2006; 157:876-84. [PMID: 16962743 DOI: 10.1016/j.resmic.2006.07.004] [Citation(s) in RCA: 460] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 06/06/2006] [Accepted: 07/18/2006] [Indexed: 12/20/2022]
Abstract
Tea is rich in polyphenols and other phenolics that have been widely reported to have beneficial health effects. However, dietary polyphenols are not completely absorbed from the gastrointestinal tract and are metabolized by the gut microflora so that they and their metabolites may accumulate to exert physiological effects. In this study, we investigated the influence of the phenolic components of a tea extract and their aromatic metabolites upon bacterial growth. Fecal homogenates containing bacteria significantly catalyzed tea phenolics, including epicatechin, catechin, 3-O-methyl gallic acid, gallic acid and caffeic acid to generate aromatic metabolites dependent on bacterial species. Different strains of intestinal bacteria had varying degrees of growth sensitivity to tea phenolics and metabolites. Growth of certain pathogenic bacteria such as Clostridium perfringens, Clostridium difficile and Bacteroides spp. was significantly repressed by tea phenolics and their derivatives, while commensal anaerobes like Clostridium spp., Bifidobacterium spp. and probiotics such as Lactobacillus sp. were less severely affected. This indicates that tea phenolics exert significant effects on the intestinal environment by modulation of the intestinal bacterial population, probably by acting as metabolic prebiotics. Our observations provide further evidence for the importance of colonic bacteria in the metabolism, absorption and potential activity of phenolics in human health and disease. The bioactivity of different phenolics may play an important role in the maintenance of gastrointestinal health.
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Affiliation(s)
- Hui Cheng Lee
- Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore 117597, Republic of Singapore
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27
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He X, Jenner AM, Ong WY, Farooqui AA, Patel SC. Lovastatin Modulates Increased Cholesterol and Oxysterol Levels and Has a Neuroprotective Effect on Rat Hippocampal Neurons After Kainate Injury. J Neuropathol Exp Neurol 2006; 65:652-63. [PMID: 16825952 DOI: 10.1097/01.jnen.0000225906.82428.69] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
This study was carried out to elucidate the effect of a brain-permeable statin (lovastatin) on cholesterol and oxysterol levels of the hippocampus after neuronal injury induced by the excitotoxin, kainic acid. Increased immunolabeling to cholesterol and the oxysterol biosynthetic enzyme, cholesterol 24-hydroxylase, was observed in the rat hippocampus after kainate lesions. This was accompanied by increased levels of cholesterol, 24-hydroxycholesterol (product of cholesterol 24-hydroxylase enzymatic activity), and 7-ketocholesterol in homogenates of the degenerating hippocampus as detected by gas chromatography/mass spectrometry. Hippocampi from rats or organotypic slices that had been treated with kainate plus lovastatin showed significantly lower levels of cholesterol, 24-hydroxycholesterol, and 7-ketocholesterol compared with those that had been treated with kainate only. Lovastatin also modulated hippocampal neuronal loss after kainate treatment in vivo and in vitro. The level of 24-hydroxycholesterol detected in vivo after kainate treatment (>50 microM) was found to be neurotoxic in hippocampal slice cultures. These results suggest that brain-permeable statins such as lovastatin could have a neuroprotective effect by limiting the levels of oxysterol in brain areas undergoing neurodegeneration.
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Affiliation(s)
- Xin He
- Department of Anatomy, National University of Singapore, Singapore, and New England Biomedical Research Center and VA Connecticut Healthcare System, Newington, CT, USA
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28
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Koh CHV, Whiteman M, Li QX, Halliwell B, Jenner AM, Wong BS, Laughton KM, Wenk M, Masters CL, Beart PM, Bernard O, Cheung NS. Chronic exposure to U18666A is associated with oxidative stress in cultured murine cortical neurons. J Neurochem 2006; 98:1278-89. [PMID: 16771828 DOI: 10.1111/j.1471-4159.2006.03958.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Findings that antioxidant treatment may be beneficial in Alzheimer's disease indicate that oxidative stress is an important factor in its pathogenesis. Studies have also suggested that cholesterol imbalance in the brain might be related to the development of neurological disorders. Previously, we have reported that U18666A, a cholesterol transport-inhibiting agent, leads to apoptosis and intracellular cholesterol accumulation in primary cortical neurons. In this study, we found that neuronal apoptosis mediated by U18666A is associated with oxidative stress in the treated cortical neurons. Cortical neurons treated with U18666A also showed decreased secretion and increased intraneuronal accumulation of beta-amyloid. The association of neuronal apoptosis with oxidative stress and Abeta accumulation may provide clues to the pathogenesis of Alzheimer's disease, as well as the role oxidative stress plays in other neurodegenerative diseases.
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Affiliation(s)
- Chor Hui Vivien Koh
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, Singapore
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29
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Lee CYJ, Isaac HB, Wang H, Huang SH, Long LH, Jenner AM, Kelly RP, Halliwell B. Cautions in the use of biomarkers of oxidative damage; the vascular and antioxidant effects of dark soy sauce in humans. Biochem Biophys Res Commun 2006; 344:906-11. [PMID: 16631617 DOI: 10.1016/j.bbrc.2006.03.217] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Accepted: 03/30/2006] [Indexed: 10/24/2022]
Abstract
Dark soy sauce (DSS) is a powerful antioxidant in vitro. We investigated whether this effect could occur in vivo and improve vascular function. Healthy human subjects were given DSS or placebo meals in a randomized, crossover study. Blood and urine were sampled before and 1, 2, 3, and 4h after the meal for F(2)-isoprostanes (total, free, and esterified) and 8OHdG measurements. Blood pressure, vascular augmentation index (AIx), and heart rate (HR) were also measured. Plasma total F(2)-isoprostanes significantly decreased 3h after placebo and the decrease was greater for DSS. Plasma free and esterified F(2)-isoprostanes were also significantly decreased after DSS. Both placebo and DSS meals increased urinary F(2)-isoprostanes at 1h but not thereafter, and lowered urinary 8OHdG levels, DBP and AIx, and increased HR. We conclude that DSS decreases lipid peroxidation in vivo. However, oxidative damage biomarkers changed after the placebo meal, a phenomenon to consider when designing interventional studies.
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Affiliation(s)
- Chung-Yung J Lee
- National University of Singapore, Yong Loo Lin School of Medicine, Department of Biochemistry, 8 Medical Drive, Singapore 117597, Singapore
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30
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Jenner AM, Rafter J, Halliwell B. Human fecal water content of phenolics: the extent of colonic exposure to aromatic compounds. Free Radic Biol Med 2005; 38:763-72. [PMID: 15721987 DOI: 10.1016/j.freeradbiomed.2004.11.020] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Revised: 11/03/2004] [Accepted: 11/15/2004] [Indexed: 12/23/2022]
Abstract
Phenolic compounds are not completely absorbed in the small intestine and so enter the colon, where they might exert physiological effects. To identify phenolics that are present in normal human colon, fecal water was prepared from 5 free-living volunteers with no dietary restrictions and analyzed by gas chromatography-mass spectrometry. Daily measurements were also performed on a single individual to examine the variation more closely. Levels of polyphenols were variable between individuals. Naringenin and quercetin had mean concentrations of 1.20 and 0.63 microM. All other flavonoids examined were present < or =0.17 microM. Simple phenolic and other aromatic acids were present at much higher concentrations. The major components were phenylacetic acid, 479 microM; 3-phenylpropionic acid, 166 microM; 3-(4-hydroxy)-phenylpropionic acid, 68 microM; 3,4-dihydroxycinnamic acid, 52 microM; benzoic acid, 51 microM; 3-hydroxyphenylacetic acid, 46 microM; and 4-hydroxyphenylacetic acid, 19 microM. Other phenolic acids ranged from 0.04 to 7 microM. Decreased dietary phenolic intake caused a decrease in polyphenol and monophenolic acid concentration in fecal water 24 h later. This study is the first to measure the range of aromatic compounds in human fecal water and demonstrates that phenolic acid concentrations are high. The biological effects of phenolics may play an important role in colon function.
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Affiliation(s)
- Andrew M Jenner
- Biochemistry Department, Faculty of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597.
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31
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Lin HS, Jenner AM, Ong CN, Huang SH, Whiteman M, Halliwell B. A high-throughput and sensitive methodology for the quantification of urinary 8-hydroxy-2'-deoxyguanosine: measurement with gas chromatography-mass spectrometry after single solid-phase extraction. Biochem J 2004; 380:541-8. [PMID: 14992687 PMCID: PMC1224185 DOI: 10.1042/bj20040004] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 02/24/2004] [Accepted: 03/02/2004] [Indexed: 11/17/2022]
Abstract
8-hydroxy-2'-deoxyguanosine (8OHdG) is a widely used biomarker for the measurement of endogenous oxidative DNA damage. A sensitive method for the quantification of 8OHdG in urine by single solid-phase extraction and GC-MS (gas chromatography with MS detection) using selective ion monitoring is described in the present study. After solid-phase extraction, samples are freeze-dried, derivatized by trimethylsilylation and analysed by GC-MS. The urinary 8OHdG was quantified using heavy isotope dilution with [18O]8OHdG. The recovery of 8OHdG after the solid-phase extraction ranged from 70 to 80% for a wide range of urinary 8OHdG levels. Using 1 ml of urine, the limit of quantification was >2.5 nM (2.5 pmol/ml) and the calibration curve was linear in the range 2.5-200 nM. This method was applied to measure 8OHdG in urine samples from 12 healthy subjects. The intra- and inter-day variations were <9%. Urinary 8OHdG levels in spot urine samples from four healthy subjects were also measured for 1 week and, again, the variation was small. The presence of H2O2 in urine did not cause artifactual formation of 8OHdG. Since this assay is simple, rapid, sensitive and reproducible, it seems suitable to be used as a routine methodology for the measurement of urinary excretion of 8OHdG in large population studies.
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Affiliation(s)
- Hai-Shu Lin
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, MD 7, Medical Drive, Singapore 117597, Singapore
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32
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Lee CYJ, Jenner AM, Halliwell B. Rapid preparation of human urine and plasma samples for analysis of F2-isoprostanes by gas chromatography-mass spectrometry. Biochem Biophys Res Commun 2004; 320:696-702. [PMID: 15240104 DOI: 10.1016/j.bbrc.2004.06.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2004] [Indexed: 02/07/2023]
Abstract
Reliable MS-based methods have been developed for the measurement of free and esterified F2-isoprostanes. However, prior to sample analysis several steps of purification, including solid-phase extraction followed by TLC or HPLC, are usually required, making it tedious to analyze large sample numbers, e.g., for population studies. We report a quick sample purification method using anion exchange solid phase extraction (SPE), which is highly selective for acidic compounds. Urine and hydrolyzed plasma of healthy individuals were acidified before SPE extraction, washed with 4 different solvent mixtures and finally eluted with ethyl acetate. The eluted samples were first derivatized with pentafluorobenzyl bromide followed by a second derivatization with bis-(trimethylsilyl)trifluoroacetamide. F2-isoprostanes were analyzed by GC-MS-NCI. The method was highly sensitive; the limit of detection at 5:1 signal-to-noise ratio was 0.037 ng/ml and 0.007 ng/mg creatinine for plasma and urine, respectively. Anion exchange SPE extraction for F2-isoprostane showed recovery of 55-65% and high linearity for concentration 0-1.0 ng/ml for urine (CV=4.08%, r2=0.990) and 0-0.5 ng/ml for plasma (CV=4.07%, r2=0.998). Fasting for 6h significantly increased plasma F2-isoprostanes levels, which has implications for the design of intervention studies using this biomarker.
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Affiliation(s)
- Chung-Yung J Lee
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore
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Lennon MA, Ireland RS, Tappin J, Ratcliffe PM, Taylor I, Turner R, Jenner AM. The personal dental service as a setting for an undergraduate clinical programme. Br Dent J 2004; 196:419-22; discussion 409. [PMID: 15071535 DOI: 10.1038/sj.bdj.4811139] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2002] [Accepted: 06/04/2003] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To investigate the feasibility and benefits of placing dental undergraduates into a general dental practice setting for part of their clinical programme. SETTING Two six-surgery general dental practices in the North West of England operating within the personal dental service of the NHS. METHOD Six volunteer final year students worked within the practices for one-day-per week for 11 weeks. Evaluation included patients', practitioners' and students' views obtained from questionnaires and/or interviews and an analysis of students' clinical records. RESULTS The students saw a large positive impact from: working alongside a dental nurse; developing their clinical skills; working in a busy practice environment; and developing interpersonal skills. Patients were very positive with 98% (44/45) being complimentary about the treatment they received, and commenting that they would be willing to participate in future student training programmes. The practice principals would also welcome continuation of the programme. CONCLUSION The programme was both feasible and educationally beneficial. The financial implications need further research.
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Affiliation(s)
- M A Lennon
- Department of Clinical Dental Sciences, University of Liverpool L69 3BX2.
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34
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Rawlingson A, Shendi K, Greenacre SA, England TG, Jenner AM, Poston RN, Halliwell B, Brain SD. Functional significance of inducible nitric oxide synthase induction and protein nitration in the thermally injured cutaneous microvasculature. Am J Pathol 2003; 162:1373-80. [PMID: 12651629 PMCID: PMC1851230 DOI: 10.1016/s0002-9440(10)63933-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Increased nitric oxide (NO) production after burn injury is well established. However, there is little information relating to the reactions that occur as a consequence of NO generation under such circumstances. We have investigated the synthesis and function of NO in a rat model of local cutaneous thermal injury. We show that NO levels are elevated from 3 hours after injury with a concomitant increase in protein nitration. A selective inducible nitric oxide synthase (iNOS) inhibitor (1400W) significantly attenuated NO synthesis, protein nitration, and neutrophil accumulation in this model, but had no effect on edema formation. The results also indicate that NO synthesis and protein nitration occurred independently of neutrophil accumulation because these parameters were unaffected by depletion of circulating neutrophils. 3-Chlorotyrosine, a marker of neutrophil/myeloperoxidase-mediated protein damage was significantly increased from 1 hour after burn. Our observations provide evidence for the involvement of reactive species in the inflammatory response after burn. The use of selective iNOS inhibitors may represent a novel approach for the management of human burn injuries.
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Affiliation(s)
- Andrew Rawlingson
- Centre for Cardiovascular Biology and Medicine, King's College London, London, United Kingdom
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35
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Ruiz E, Siow RCM, Bartlett SR, Jenner AM, Sato H, Bannai S, Mann GE. Vitamin C inhibits diethylmaleate-induced L-cystine transport in human vascular smooth muscle cells. Free Radic Biol Med 2003; 34:103-10. [PMID: 12498985 DOI: 10.1016/s0891-5849(02)01192-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Adaptive increases in intracellular glutathione (GSH) in response to oxidative stress are mediated by induction of L-cystine uptake via the anionic amino acid transport system x(c)(-). The recently cloned transporter xCT forms a heteromultimeric complex with the heavy chain of 4F2 cell surface antigen (4F2hc/CD98). Depletion of GSH by the electrophile diethylmaleate (DEM) induces the activity and expression of xCT in peritoneal macrophages. We here examine the effects of vitamin C on induction of xCT by DEM in human umbilical artery smooth muscle cells. DEM caused time- (3-24 h) and concentration- (25-100 microM) dependent increases in L-cystine transport, with GSH depleted by 50% after 6 h and restored to basal values after 24 h. xCT mRNA levels increased after 4 h DEM treatment with negligible changes detected for 4F2hc mRNA. DEM caused a rapid (5-30 min) phosphorylation of p38(MAPK). Inhibition of p38(MAPK) by SB203580 (10 microM) enhanced DEM-induced increases in L-cystine transport and GSH, whereas inhibition of p42/p44(MAPK) (PD98059, 10 microM) had no effect. Pretreatment of cells with vitamin C (100 microM, 24 h) attenuated DEM-induced adaptive increases in L-cystine transport and GSH levels. Inhibition of p38(MAPK), but not p42/p44(MAPK), reduced the cytoprotective action of vitamin C. Our findings suggest that DEM induces activation of xCT via intracellular signaling pathways involving p38(MAPK), and that vitamin C, in addition to its antioxidant properties, may modulate this signaling pathway to protect smooth muscle cells from injury.
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Affiliation(s)
- Emilio Ruiz
- Centre for Cardiovascular Biology and Medicine, GKT School of Biomedical Sciences, King's College, University of London, London, UK
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36
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Jenner AM, Ruiz JE, Dunster C, Halliwell B, Mann GE, Siow RCM. Vitamin C protects against hypochlorous Acid-induced glutathione depletion and DNA base and protein damage in human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 2002; 22:574-80. [PMID: 11950693 DOI: 10.1161/01.atv.0000013785.03265.5c] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hypochlorous acid (HOCl), generated by myeloperoxidase released from activated macrophages, is thought to contribute to vascular dysfunction and oxidation of low density lipoproteins (LDLs) in atherogenesis. We have previously shown that HOCl exposure can cause chlorination and oxidation of isolated DNA and that vitamin C protects human arterial smooth muscle cells against oxidized LDL-mediated damage. We report in the present study that vitamin C attenuates HOCl-induced DNA base and protein damage and depletion of intracellular glutathione (GSH) and ATP in human arterial smooth muscle cells. Cells were pretreated in the absence or presence of 100 micromol/L vitamin C (24 hours) and then exposed to HOCl (0 to 500 micromol/L, 0 to 60 minutes) in the absence of vitamin C. Intracellular GSH and ATP levels were depleted by HOCl treatment, and gas chromatography-mass spectroscopy revealed a concentration- and time-dependent increase in DNA base oxidation and protein damage (measured as 3-chlorotyrosine). Pretreatment of smooth muscle cells with vitamin C significantly reduced the extent of HOCl-induced DNA and protein damage and attenuated decreases in intracellular ATP and GSH. Our findings suggest that physiological levels of vitamin C provide an important antioxidant defense against HOCl-mediated injury in atherosclerosis.
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Affiliation(s)
- Andrew M Jenner
- Centre for Cardiovascular Biology and Medicine, Guy's, King's and St. Thomas' School of Biomedical Sciences, King's College, University of London, London, UK
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37
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Abstract
OBJECTIVE To achieve consensus within primary dental care on the contents of a clinical minimum data set to measure oral health status. DESIGN Using the Delphi process a simple random sample of 30 LDCs and 10 CDS services in England were asked to rank a list of existing clinical indicators in order of their perceived importance as a means of measuring oral health. A nominated panel representing the stakeholder organisations of primary dental care reviewed this ranking and identified a core group of clinical indicators to be included in a clinical minimum data set. RESULTS An 80 percent response rate to the Delphi process was achieved. Consensus was reached on a core group of 10 indicators, which can provide information on patient's perceptions of pain, function and appearance, and professional measurements of caries, teeth present, periodontal disease, oral sepsis, presence of mucosal pathology and tooth wear. CONCLUSIONS A representative sample of primary care dentists in England and the key representative organisations of primary dental care achieved consensus on the contents of a clinical minimum data set to record oral health status in primary dental care. This is a first step in standardising the measurement of oral health status across primary care.
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Affiliation(s)
- R S Ireland
- University of Liverpool, Liverpool Dental Hospital and School of Dentistry.
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Abstract
1. It has been demonstrated that hydrazine is metabolized by rat liver enzymes located in the microsomal fraction. This metabolism was reduced in the absence of oxygen or NADPH and was increased by NADH in the presence of NADPH. 2. Microsomal enzyme inhibitors, piperonyl butoxide and metyrapone, significantly inhibited hydrazine metabolism but glutathione had no affect and was not depleted. 3. In addition to P450, flavin monooxygenase may also be involved in catalysing the microsomal metabolism of hydrazine. 4. Liver microsomes prepared from either beta-naphthoflavone, acetone or the isoniazid-pretreated rat did not show a significant increase in hydrazine metabolism compared with microsomes from the control rat. However, although phenobarbitone pretreatment increased overall microsomal hydrazine metabolism this was not increased relative to P450 content. 5. Hydrazine metabolism was 20-70% lower in human microsomes prepared from three individuals compared with the control rat. 6. Hydrazine is also metabolized by rat liver mitochondria but the monoamine oxidase inhibitors clorgyline and pargyline do not significantly decrease this.
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Affiliation(s)
- A M Jenner
- Toxicology Department, School of Pharmacy, University of London, UK
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39
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Arch LM, Jenner AM, Whittle JG. The views and expectations regarding dental care of the parents of children with special dental needs: a survey in the County of Cheshire, England. Int J Paediatr Dent 1994; 4:127-32. [PMID: 7748852 DOI: 10.1111/j.1365-263x.1994.tb00116.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A postal questionnaire of multiple-choice design was sent to 122 parents of children with special dental needs in the county of Cheshire, England, with the aim of determining parents' views and expectations of dental care. Replies were received from 85 (70%). Eighty respondents (94%) were in favour of preventive dental advice being given to their children and 83 (98%) felt that an explanation should be given of the risk to general health posed by dental disease or its treatment. A high proportion of parents felt that simple dietary and oral hygiene advice was necessary, that the benefits of fluoride supplementation should be explained and that free fluoride supplements should be issued. The 'family dentist' was most favoured as the source of advice, closely followed by a community dental officer. Likewise the dental surgery was the most popular location for receiving advice, and doctors' surgeries were the least favoured. Parental support for regular school dental screening examinations of all children was extremely high and parents thought that special-needs children should be examined more frequently.
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Affiliation(s)
- L M Arch
- Department of Community Dental Health, Chester and Halton Community NHS Trust, Chester, England
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40
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Abstract
Hydrazine hepatotoxicity in vivo, as manifested by triglyceride accumulation, depletion of ATP and reduced glutathione (GSH) was shown to be dose related. The effect of pretreatment of rats with various inhibitors and inducers of cytochrome P450 on these dose-response relationships was investigated. Pretreatment with the inhibitor piperonyl butoxide increased triglyceride accumulation whereas pretreatment with the inducers phenobarbital and beta-naphthoflavone (BNF) resulted in reduced triglyceride accumulation. Pretreatment with the inducers acetone and isoniazid also enhanced triglyceride accumulation. Only phenobarbital pretreatment also significantly reduced GSH and ATP depletion. A linear correlation was found between hepatic glutathione and ATP levels in non-pretreated animals given various doses of hydrazine. However, exponential relationships were found between hepatic triglycerides and both hepatic ATP and glutathione. The results suggest that i) the hepatotoxicity of hydrazine can be modulated by inducing or inhibiting particular isoenzymes of cytochrome P450, ii) ATP and GSH depletion may not be directly involved in the development of fatty liver.
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Affiliation(s)
- A M Jenner
- Toxicology Department, School of Pharmacy, University of London, UK
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Jenner AM, Timbrell JA. Effect of acute and repeated exposure to low doses of hydrazine on hepatic microsomal enzymes and biochemical parameters in vivo. Arch Toxicol 1994; 68:240-5. [PMID: 8067896 DOI: 10.1007/s002040050063] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A single dose of hydrazine (3 mg.kg-1 i.p.) caused hepatic accumulation of triglycerides and depletion of ATP in rats after 9 h. Repeated exposure of rats to hydrazine (approximately equal to 2.5 mg.kg-1 per day) for 10 days resulted in depletion of hepatic reduced glutathione (GSH) and triglycerides. Repeated exposure to hydrazine also caused a significant (time dependent) induction of p-nitrophenol hydroxylase (NPH) activity together with changes in other hepatic microsomal enzymes. These included 7-pentoxyresorufin O-deethylase (PROD) and 7-ethoxyresorufin O-de ethylase (EROD) activity, total cytochrome P450, cytochrome b5 and cytochrome P450 reductase activity. Repeated exposure to lower levels of hydrazine (approximately equal to 0.250 mg.kg-1 per day) caused no significant hepatic biochemical or microsomal changes after 5 or 10 days except for an increase in NPH activity (17%) and liver ATP (15%) after 5 days.
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Affiliation(s)
- A M Jenner
- Toxicology Department, School of Pharmacy, University of London, UK
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Jones S, Crawford AC, Jenner AM, Roberts JT, Lennon MA. The possibility of school milk as a vehicle for fluoride: epidemiological, organisational and legal considerations. Community Dent Health 1992; 9:335-42. [PMID: 1486521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The aim of this study was to investigate the epidemiological, organisational and legal considerations of using school milk as a vehicle for fluoride. The background to the work was the need to develop alternative methods of fluoride supplementation for high risk groups living in areas where water fluoridation is unlikely. St Helens in Merseyside was chosen as the study area, where 23 per cent of 4-year-old children were identified as having a high caries experience (dmft > or = 4). It was found that 65 per cent of 3 and 4-year-old children attend local authority educational facilities, where milk is provided on a daily basis for children aged 2 to 7 years. This group included 62 per cent of the 4-year-old group with high caries experience. The legal aspects of adding fluoride to milk were found to be complex but it was concluded that there may be considerable potential for using school milk as a vehicle for fluoride, and a large-scale study is now planned.
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Affiliation(s)
- S Jones
- Department of Clinical Dental Sciences, University of Liverpool, UK
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Zoitopoulos L, Jenner AM. Referral of child patients from the Community Dental Service to the General Dental Service: one year's experience. Br Dent J 1991; 170:4-5. [PMID: 2001300 DOI: 10.1038/sj.bdj.4807400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The Community Dental Service has been encouraged to refer regular attending patients to General Dental Practice whilst maintaining a monitoring system to ensure that referred patients do not 'fall through the net'. The referral and monitoring system run by Halton Health Authority for one year is described. During this period 112 motivated patients were identified as being suitable for referral to general practice. Of these, 85 agreed to referral and 27 refused. Of those referred, 69 subsequently attended but 16 failed to attend and 14 of these did not respond to a further recall by the CDS. Far from acting as a safety net service the CDS may, in pursuing this referral policy, be actually increasing the number of irregular attenders in some localities and for this reason Halton is reviewing the speed with which the referral policy is being implemented.
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Jenner AM, Lennon MA. An evaluation of the school dental inspection. Community Dent Health 1986; 3:221-6. [PMID: 3463382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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