In Vivo Measurement of Aluminum in Alzheimer's Disease and Related Studies

Abstract

Alzheimer’s disease accounts for up to 80% of the cases of dementia making it the most common type of dementia. As of 2015, 46.8 million people are suffering from Alzheimer’s disease worldwide with an alarming rate of increase in the onset of the disease. Despite the ongoing research, the true cause of Alzheimer’s disease remains unknown. Aluminum is one of the major environmental toxins linked to the etiology of Alzheimer’s disease. A pilot clinical study for non-invasive measurement of bone aluminum was performed at the in vivo neutron activation analysis facility at McMaster University including 15 Alzheimer’s and 15 control subjects. A significant difference in bone aluminum, relative to calcium, was found between the two groups. Multiple methods of analysis were investigated to determine the method with the lowest minimum detection limit. The method of in vivo neutron activation analysis allows for the simultaneous activation of multiple elements. As such, it was possible to measure the magnesium levels, which has been shown to be involved in Alzheimer’s disease, in the study subjects. The results of bone measurements did not show a significant association between bone magnesium levels and Alzheimer’s disease. Moreover, the short-term kinetic behaviours of sodium and chlorine, both essential for the human body, were studied. The outcome of this study revealed an increase in the biological half-lives of sodium and chlorine with age and a higher variability in Alzheimer’s patients compared to control subjects. Finally, bone samples from parenteral nutrition patients were analyzed to determine their aluminum content for comparison and benchmarking purposes. The present results suggest a possible association between bone aluminum and the presence of Alzheimer’s disease. No such association was found for magnesium or the biological half-lives of sodium and chlorine. The technique of in vivo neutron activation analysis was shown to be a promising tool for measuring bone aluminum and magnesium; however, a better detection limit is required to strengthen the current results.