According to a new study in mice published online in the journal PLoS Biology, a probable cause of the Alzheimer's disease is the release from the blood into the brain of particles carrying fat and toxic liver proteins.
“We have identified the likely 'blood-brain pathway' that may lead to Alzheimer's, the most prevalent form of dementia globally,” says the study's senior author, Professor John Mamo, director of the Curtin Health Innovation Research Institute at Curtin University.
We knew that the defining characteristic of people living with Alzheimer's disease was the progressive accumulation of toxic protein deposits within the brain called beta-amyloid. What we didn't know is where the amyloid came from, or why it settled in the brain. We now know that these toxic protein deposits are carried into the brain by particles produced by the liver called lipoproteins.
John Mamo
Managing the liver, managing Alzheimer's?
“This blood-brain pathway originating from the liver is significant,” says the scientist. "Because if we can manage blood levels of lipoprotein amyloid and prevent their leakage into the brain, this opens up potential new treatments to prevent Alzheimer's and slow memory loss."
Building on previous research showing that beta-amyloid is produced outside the brain with lipoproteins, Professor Mamo and his colleagues tested the blood-brain pathway by genetically engineering mouse models. Mice with livers "engineered" to produce human lipoproteins.
The results
“It's as we predicted,” Mamo says. ”The study found that mouse models producing lipoprotein-amyloid in the liver suffered from inflammation in the brain. Not only that: they accelerated the death of brain cells and memory loss,” said Professor Mamo.
Further studies are needed, including tests on human subjects. An important window opens up, however. This discovery shows that the abundance of these toxic protein deposits in the blood could potentially be addressed through a person's diet.
