Summary: Researchers found a close association between high aluminum content in brain tissue and amyloid-beta location in post-mortem samples of people with familial Alzheimer’s disease. The findings back up previous claims that aluminum exposure may be linked to the development of the neurodegenerative disease.
Source: IOS Press
A new study published in the Journal of Alzheimer’s Disease (JAD) supports a growing body of research that links human exposure to aluminum with Alzheimer’s disease (AD). Researchers found significant amounts of aluminum content in brain tissue from donors with familial AD. The study also found a high degree of co-location with the amyloid-beta protein, which leads to early onset of the disease.
“This is the second study confirming significantly high brain accumulation in familial Alzheimer’s disease, but it is the first to demonstrate an unequivocal association between the location of aluminum and amyloid-beta in the disease. It shows that aluminum and amyloid-beta are intimately woven in the neuropathology,” explained lead investigator Christopher Exley, PhD, Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire, UK.
An association between aluminum and amyloid-beta has been suggested for over 40 years. In an earlier study, brain tissue from donors in the United Kingdom diagnosed with familial AD showed significant accumulations of aluminum. To further understand this relationship, in the current study the researchers measured aluminum in the brain tissue of a cohort of Colombian donors with familial AD who shared a specific mutation. The mutation leads to elevated levels of amyloid-beta, early disease onset, and an aggressive disease etiology. The levels were compared with a control set of brain tissues from donors with no diagnosis of neuropathological disease. They also used aluminum-specific fluorescence microscopy imaging to investigate the relationship between aluminum and amyloid-beta in familial AD.
The results were striking. The aluminum content of the brain tissue from donors with the genetic mutation was universally high, with 42% of tissues having a level considered pathologically significant, and the levels were significantly higher than those in the control set. The imaging studies identified aluminum deposits in all brain tissues studied. They were predominantly co-located with amyloid-beta in senile plaques and occasionally in the brain vasculature. Aluminum was also found separately from amyloid-beta in intracellular compartments including glia and neuronal axons. The results strongly suggest that genetic predispositions known to increase amyloid-beta in brain tissue also predispose individuals to accumulate and retain aluminum in brain tissue.
“Compelling localization of aluminum with a central player in AD, amyloid-beta, strengthens the link of aluminum to the pathogenesis of AD,” commented George Perry, PhD, Professor of Biology, Semmes Distinguished University Chair in Neurobiology, University of Texas at San Antonio, and Editor-in-Chief of JAD.
“One could envisage increased amyloid-beta in brain tissue as a response to high levels of aluminum content, or that aluminum fosters the accumulation of amyloid-beta,” said Dr. Exley. “Either way, the new research confirms my resolve that within the normal lifespan of humans, there would not be any AD if there were no aluminum in the brain tissue. No aluminum, no AD.”
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IOS Press
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The image is credited to the researchers.
Original Research: Open access
“Aluminum and Amyloid-β in Familial Alzheimer’s Disease”. Mold, Matthew; Linhart, Caroline; Gómez-Ramírez, Johana; Villegas-Lanau, Andrés; Exley, Christopher.
Journal of Alzheimer’s Disease doi:10.3233/JAD-191140.
Abstract
Aluminum and Amyloid-β in Familial Alzheimer’s Disease
Genetic predispositions associated with metabolism of the amyloid-β protein precursor underlie familial Alzheimer’s disease; a form of dementia characterized by early disease onset and elevated levels of cortical amyloid-β. Human exposure to aluminum is linked to the etiology of Alzheimer’s disease and recent research measured a high content of aluminum in brain tissue in familial Alzheimer’s disease. To elaborate upon this finding, we have obtained brain tissues from a Colombian cohort of donors with familial Alzheimer’s disease. We have used established methods to measure the aluminum content of these tissues and we have compared the data with a recently measured dataset for control brain tissues. We report significantly higher levels of aluminum in brain tissues in donors with familial Alzheimer’s disease than in control tissues from donors without neurological impairment or neurodegeneration. We have used aluminum-specific fluorescence microscopy along with complementary imaging for amyloid-β to demonstrate a very high degree of co-localization of these two risk factors in brain tissue in familial Alzheimer’s disease. Aluminum and amyloid-β were co-located in senile plaques as well as vasculature, the latter resembling cerebral amyloid angiopathy. Aluminum was also found separately from amyloid-β in intracellular compartments including glia and neuronal axons. The research has identified an arguably unique association between high brain aluminum content and amyloid-β and allows postulation that genetic predispositions defining familial Alzheimer’s disease underlie this relationship.