title: Alkali metals levels in the human brain tissue: Anatomical region differences and age-related changes.
abstract: The link between trace elements imbalances (both "toxic" and "essential") in the human brain and neurodegenerative disease has been subject of extensive research. More recently, some studies have highlighted the potential role of the homeostasis deregulation of alkali metals in specific brain regions as key factor in the pathogenesis of neurodegenerative diseases such as multiple sclerosis and Alzheimer's disease. Using flame atomic emission spectrometry and inductively coupled plasma-mass spectrometry after microwave-assisted acid digestion of the samples, alkali metals (Na, K, Li, Rb and Cs) were determined in 14 different areas of the human brain (frontal cortex, superior and middle temporal gyri, caudate nucleus, putamen, globus pallidus, cingulated gyrus, hippocampus, inferior parietal lobule, visual cortex of the occipital lobe, midbrain, pons, medulla and cerebellum) of adult individuals (n=42; 71±12, range: 50-101 years old) with no known history and evidence of neurodegenerative, neurological or psychiatric disorder. Potassium was found as the most abundant alkali metal, followed by Na, Rb, Cs and Li. Lithium, K and Cs distribution showed to be quite heterogeneous. On the contrary, Rb and Na appeared quite homogeneously distributed within the human brain tissue. The lowest levels of Na, K, Rb and Li were found in the brainstem (midbrain, medulla and pons) and cerebellum, while the lowest levels of Cs were found in the frontal cortex. The highest levels of K (mean±sd; range 15.5±2.5; 8.9-21.8mg/g) Rb (17.2±6.1; 3.9-32.4μg/g and Cs (83.4±48.6; 17.3-220.5ng/g) were found in putamen. The highest levels of Na and Li were found in the frontal cortex (11.6±2.4; 6.6-17.1mg/g) and caudate nucleus (7.6±4.6 2.2-21.3ng/g), respectively. Although K, Cs and Li levels appear to remain largely unchanged with age, some age-related changes were observed for Na and Rb levels in particular brain regions (namely in the hippocampus).
authors.affiliation: LAQV/REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, Porto University, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Ramos
authors.affiliation: National Institute of Legal Medicine and Forensic Sciences - North Branch, Jardim Carrilho Videira, 4050-167 Porto, Portugal; CENCIFOR - Forensic Science Center, Largo da Sé Nova, s/n, 3000-213 Coimbra, Portugal; Faculty of Medicine, Porto University, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; School of Health Sciences, Minho University, Campus of Gualtar, 4710-057 Braga, Portugal.
authors.forename: Agostinho
authors.initials: A
authors.lastname: Santos
authors.affiliation: LAQV/REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, Porto University, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal; CISA, Research Centre on Environment and Health, School of Allied Health Sciences, Polytechnic Institute of Porto, Rua Valente Perfeito 322, 4400-330 Vila Nova de Gaia, Portugal.
authors.forename: Edgar
authors.initials: E
authors.lastname: Pinto
authors.affiliation: CENCIFOR - Forensic Science Center, Largo da Sé Nova, s/n, 3000-213 Coimbra, Portugal.
authors.forename: Nair Rosas
authors.initials: NR
authors.lastname: Pinto
authors.affiliation: CENCIFOR - Forensic Science Center, Largo da Sé Nova, s/n, 3000-213 Coimbra, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Mendes
authors.affiliation: CENCIFOR - Forensic Science Center, Largo da Sé Nova, s/n, 3000-213 Coimbra, Portugal; Faculty of Medicine, Porto University, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; Institute of Research and Advanced Training in Health Sciences and Technologies (IINFACTS), Department of Sciences, University Institute of Health Sciences (IUCS), CESPU, R. Central da Gandra 1317, 4585-116 Gandra, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Magalhães
authors.affiliation: LAQV/REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, Porto University, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal. Electronic address: aalmeida@ff.up.pt.
authors.forename: Agostinho
authors.initials: A
authors.lastname: Almeida
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001921:Brain / Q000033:anatomy & histology* / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008672:Metals, Alkali / Q000032:analysis* / Q000378:metabolism*; D008875:Middle Aged
chemical_list: D008672:Metals, Alkali
keywords: Ageing; Alkali metals; Human brain; Postmortem analysis