title: Selenium Levels in Serum, Red Blood Cells, and Cerebrospinal Fluid of Alzheimer's Disease Patients: A Report from the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL).
abstract: Selenium (Se) protects cells against oxidative stress damage through a range of bioactive selenoproteins. Increased oxidative stress is a prominent feature of Alzheimer's disease (AD), and previous studies have shown that Se deficiency is associated with age-related cognitive decline. In this study, we assessed Se status in different biofluids from a subgroup of participants in the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing. As Se in humans can either be an active component of selenoproteins or inactive via non-specific incorporation into other proteins, we used both size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) and tandem mass spectrometry to characterize selenoproteins in serum. We observed no differences in total Se concentration in serum or cerebrospinal fluid of AD subjects compared to mildly cognitively impairment patients and healthy controls. However, Se levels in erythrocytes were decreased in AD compared to controls. SEC-ICP-MS analysis revealed a dominant Se-containing fraction. This fraction was subjected to standard protein purification and a bottom-up proteomics approach to confirm that the abundant Se in the fraction was due, in part, to selenoprotein P. The lack of change in the Se level is at odds with our previous observations in a Brazilian population deficient in Se, and we attribute this to the Australian cohort being Se-replete.
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, SP, Brazil.
authors.forename: Bárbara R
authors.initials: BR
authors.lastname: Cardoso
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Elemental Bio-imaging Facility, University of Technology Sydney, Broadway, NSW, Australia.
authors.forename: Dominic J
authors.initials: DJ
authors.lastname: Hare
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Cooperative Research Centre for Mental Health, Parkville, VIC, Australia.
authors.forename: Ashley I
authors.initials: AI
authors.lastname: Bush
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Qiao-Xin
authors.initials: QX
authors.lastname: Li
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Fowler
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Colin L
authors.initials: CL
authors.lastname: Masters
authors.affiliation: Edith Cowan University, School of Exercise, Biomedical and Health Sciences, Joondalup, WA, Australia.
authors.forename: Ralph N
authors.initials: RN
authors.lastname: Martins
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Katherine
authors.initials: K
authors.lastname: Ganio
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Cooperative Research Centre for Mental Health, Parkville, VIC, Australia.
authors.forename: Amber
authors.initials: A
authors.lastname: Lothian
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata, India.
authors.forename: Soumya
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Cooperative Research Centre for Mental Health, Parkville, VIC, Australia.|Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Kapp
authors.affiliation: The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.|Cooperative Research Centre for Mental Health, Parkville, VIC, Australia.
authors.forename: Blaine R
authors.initials: BR
authors.lastname: Roberts
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood* / Q000134:cerebrospinal fluid* / Q000235:genetics; D053327:Apolipoprotein E4 / Q000235:genetics; D015415:Biomarkers / Q000097:blood / Q000134:cerebrospinal fluid; D060825:Cognitive Dysfunction / Q000097:blood* / Q000134:cerebrospinal fluid* / Q000235:genetics; D015331:Cohort Studies; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D040901:Proteomics; D012643:Selenium / Q000097:blood* / Q000134:cerebrospinal fluid*
chemical_list: D053327:Apolipoprotein E4; D015415:Biomarkers; D012643:Selenium
keywords: Alzheimer’s disease; cognition; selenium; selenocysteine; selenoproteins