The preclinical study, conducted in the mouse model of Alzheimer’s, modified with amyloid precursor proteins, was to assess the effects of replacing blood with whole blood from healthy mice. Lead author Dr. Claudio Soto, Professor in the Department of Neurology summarizes the findings: “We provide proof of concept and promise of technologies commonly used in medical practice, such as plasmapheresis or blood ‘dialysis’, to purify the blood, in this case of patients with Alzheimer’s disease, to reduce the accumulation of toxic substances in the brain”.
Treat disease through the bloodstream rather than in the brain
This is a considerable advantage of this new alternative which does not require, in particular, the passage of therapeutic agents across the blood-brain barrier. Previous studies have already shown that the misfolding, aggregation and accumulation of beta-amyloid proteins in the brain play a central role in Alzheimer’s disease, but, with this work, it seems possible to prevent these process by manipulation of circulating blood components:
“The blood vessels in the brain are classically considered the most impermeable barrier in the body, however this barrier is also a very specialized interface between the brain and the systemic circulation”write the researchers.
- After several blood transfusions, the development of cerebral amyloid plaques in the transgenic mouse model of Alzheimer’s disease appears to be reduced by 40% to 80%;
- this reduction in amyloid plaques is accompanied by a decrease in plaque growth rates over time and allows for improved spatial memory performance in animals.
What mechanism? The exact mechanism by which this blood exchange reduces amyloid pathology and improves memory remains poorly understood, however scientists have several hypotheses:
- the decrease in beta-amyloid proteins in the bloodstream could promote the redistribution of the peptide from the brain to the peripheral circulation;
- blood exchange could prevent the influx of beta-amyloid.
If these mechanisms of action remain to be clarified, the “change of blood” is envisaged, for the first time, as a promising avenue for the treatment of Alzheimer’s disease. A track that warrants further research.