It's known since some time that there is a link between blood and Alzheimer disease.
For example in 2019, after being dosed with GRF6021, a drug proposed by Alkahest, a California-based startup, Alzheimer's patients in a clinical trial retained memory and mental function for six months - when they would normally be expected to deteriorate. GRF6021, a drug proposed by Alkahest, a California-based startup, is made from the blood of young people.
On contrary a large study found that people who experienced a blood transfusion may be at risk of Alzheimer's disease or may be, because they were transfused with "old blood".
A research team led by Claudio Soto, in the Department of Neurology with McGovern Medical School at UTHealth Houston, with Akihiko Urayama, as first author, performed a series of whole blood exchange treatments to partially replace blood from mice exhibiting Alzheimer's disease-causing amyloid precursor proteins with complete blood from healthy mice of the same genetic background.
The results of the study was published in Molecular Psychiatry.
The development of cerebral amyloid plaques in a transgenic mice model of AD (Tg2576) was significantly reduced by 40–80% through exchanging whole blood with normal blood from wild type mice having the same genetic background. Importantly, such reduction resulted in improvement in spatial memory performance in aged Tg2576 mice.
The exact mechanism by which blood exchange reduces amyloid pathology and improves memory is presently unknown, but measurements of Aβ in plasma soon after blood exchange suggest that mobilization of Aβ from the brain to blood may be implicated.
Their results suggest that a target for AD therapy may exist in the peripheral circulation, which could open a novel disease-modifying intervention for AD. Technologies commonly used in medical practice, such as plasmapheresis or blood dialysis, could 'clean' blood from Alzheimer's patients, reducing the buildup of toxic substances in the brain.