Is the Gut a Significant Source of Amyloid- β in Alzheimer ' s Disease?

The early stages of Alzheimer's disease are characterized by rising levels of amyloid-β in the brain and the formation of misfolded amyloid aggregates. It is presently thought that this is a necessary precursor for the more harmful later stages of the condition, in which chronic inflammation and tau aggregation cause widespread cell death in the brain. It has been noted that amyloid-β exists outside the brain, and there is evidence for levels of amyloid-β in the vasculature to be in dynamic equilibrium with amyloid-β in the brain. Clearing amyloid-β from the bloodstream has shown some promise as an approach to reduce levels in the brain. You may recall that the misfolded α-synuclein aggregates found in Parkinson's disease are now thought to originate in the gut in a sizable number of patients and thereafter spread to the brain. Analogously, in today's open access paper, researchers present evidence for the gut to provide a significant source of amyloid-β that is transported to the brain via the vasculature. This coincides with the evidence for Alzheimer's patients to have a significantly altered gut microbiome composition. Perhaps this affects the risk of disease via increased microbiome-spurred inflammation, but perhaps it is also generating increased amyloid-β to the point of overwhelming the clearance mechanisms in brain tissue. In this context, it is worth noting the point that a major route of clearance of molecular waste from the brain is via drain...
Source: Fight Aging! - Category: Research Authors: Tags: Medicine, Biotech, Research Source Type: blogs