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Rubidium and potassium levels are altered in Alzheimer's disease brain and blood but not in cerebrospinal fluid

  • Blaine R. Roberts
  • , James D. Doecke
  • , Alan Rembach
  • , L. Fernanda Yévenes
  • , Christopher J. Fowler
  • , Catriona A. McLean
  • , Monica Lind
  • , Irene Volitakis
  • , Colin L. Masters
  • , Ashley I. Bush
  • , Dominic J. Hare
  • , the Australian Imaging Biomarkers and Lifestyle (AIBL) Research Group

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Loss of intracellular compartmentalization of potassium is a biochemical feature of Alzheimer's disease indicating a loss of membrane integrity and mitochondrial dysfunction. We examined potassium and rubidium (a biological proxy for potassium) in brain tissue, blood fractions and cerebrospinal fluid from Alzheimer's disease and healthy control subjects to investigate the diagnostic potential of these two metal ions. We found that both potassium and rubidium levels were significantly decreased across all intracellular compartments in the Alzheimer's disease brain. Serum from over 1000 participants in the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing (AIBL), showed minor changes according to disease state. Potassium and rubidium levels in erythrocytes and cerebrospinal fluid were not significantly different according to disease state, and rubidium was slightly decreased in Alzheimer's disease patients compared to healthy controls. Our data provides evidence that contrasts the hypothesized disruption of the blood-brain barrier in Alzheimer's disease, with the systemic decrease in cortical potassium and rubidium levels suggesting influx of ions from the blood is minimal and that the observed changes are more likely indicative of an internal energy crisis within the brain. These findings may be the basis for potential diagnostic imaging studies using radioactive potassium and rubidium tracers.

Original languageEnglish
Article number119
Number of pages8
JournalActa Neuropathologica Communications
Volume4
Issue number1
DOIs
Publication statusPublished - 14 Nov 2016

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