Fe, Zn, Se and Na increases in brains of individuals with cognitive decline

Abstract

Background: Although it has been known that trace elements play an essential role in the human metabolism, the role of these elements in neurological diseases still remains uncertain. Methods: Brain samples from 22 normal and 28 demented individuals of both genders aged more than 50 years from the Brain Bank of the Brazilian Ageing Brain Study Group. The brain samples were cut using a titanium knife and then freeze-dried. Neutron activation analysis was applied to assess Fe, Zn, Se, Na, K, Rb concentrations. Certified reference materials, NIST 1566b Oyster Tissue and NIST 1577b Bovine Liver were analyzed for quality of the analytical results. Cognitive evaluation was retrospectively gathered through a semi-structured interview using the Clinical Dementia Scale (CDR) and Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). Participants were classified as cognitively normal if the CDR was 0 and the IQCODE 3.20 and as demented if the CDR was 2 and the IQCODE 3.80. Results: Comparisons between the results obtained for the hippocampus of normal and demented individuals showed significantly higher concentrations of Fe, Na, Se and Zn in the hippocampus of demented individual group (p0.05). On the other hand, the hippocampus of the demented group presented lower K and Rb concentrations when compared to the hippocampus of the normal group. Conclusions: It is possible that the disequilibrium found in this study could be related to cognitive decline. However, further analysis with a larger group of both normal and demented individuals, including intermediate rates of cognitive decline, is needed.