A group of patients with inherited forms of Alzheimer’s disease was found to have extremely high brain-aluminum levels, leading researchers to suggest there might be a link between genetic vulnerability to the condition and a higher susceptibility to accumulate aluminum in the brain.
“Aluminium in brain tissue in familial Alzheimer’s disease” recorded some of the highest brain-aluminum levels ever measured, and suggested that the metal could be a factor in amyloid-beta aggregation. The report was published in the Journal of Trace Elements in Medicine and Biology.
Abnormally high aluminum levels have been found in the brains of patients with sporadic Alzheimer’s, but no studies had examined levels in patients with familial versions of the neurodegenerative condition.
Researchers at Keele University in England autopsied the brains of 12 familial Alzheimer’s patients. The patients were 42 to 86 years old and had been diagnosed by genetic analysis or the presence of disease in close relatives, along with an early disease onset.
The team found aluminum in all 144 brain parts examined. Levels above 2 micrograms per gram of tissue are considered concerning, and about 40% of all the examined tissue had content higher than that. More than half the tissue — 58% — had levels higher than 3 micrograms, which is considered a significant hazard.
In 11 of the patients, the team found at least one brain region with aluminum levels in a hazardous range. Five patients had levels higher than 10 micrograms, with the highest concentration being 35.65 micrograms per gram of tissue.
Aluminum amounts that high typically are only found in cases of aluminum-triggered encephalopathy, a brain disease that can develop as a result of a person’s occupation or significant exposure to aluminum-containing drugs.
Researchers also found aluminum deposits in the gray matter, concentrated in clusters.
They noted that the extracellular deposits looked like amyloid-beta deposits.
“These data, supported by visual evidence of aluminium in brain tissue, raise the possibility that genetic predisposition to AD is accompanied by a higher propensity to accumulate and retain aluminium in the brain,” the researchers wrote.
In earlier work, the team showed that aluminum clustered in the same spots as amyloid-beta in the brain of an Alzheimer’s patient. Other studies have shown that amyloid-beta binds aluminum, which triggers precipitation of amyloid aggregates.
Amyloid-beta’s role in familial Alzheimer’s is more established than its part in sporadic cases. These data indicate that aluminum can contribute to all types of Alzheimer’s disease.