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Early research indicates blood exchanges could be a potential treatment for Alzheimer’s disease. FG Trade/Getty Images
  • A study used mice to test whether blood transfusions could reduce levels of amyloid plaque associated with Alzheimer’s disease.
  • Researchers reported that this treatment significantly improved symptoms of Alzheimer’s and reduced plaques in the brains of mice.
  • Experts say complete blood transfusion can’t be done in humans, but they plan to try blood dialysis and blood plasma exchange next to see if the mice respond to this equally well, which could lead to human trials.

Researchers say that the complete exchange of blood might be a new, disease-modifying treatment for Alzheimer’s disease.

Their new study, recently published in the journal Molecular Psychiatry, reports that this treatment successfully reduced the development of a protein associated with the disease called amyloid plaque in the brains of mice.

Claudio Soto, Ph.D., a lead study author and a professor in the Department of Neurology at McGovern Medical School at UTHealth Houston, told Healthline the study was motivated by his previous findings that “toxic materials” in the blood of Alzheimer’s disease patients may contribute to brain damage caused by the disease.

“We proceed with this proof-of-concept study to see if by replacing the blood of an animal model of [Alzheimer’s disease] with blood from healthy mice, we could decrease the disease in the brain,” he said.

Soto says this approach could allow the disease to be treated through the circulatory system instead of trying to cross the blood-brain barrier by sending drugs to the brain.

Researchers used transgenic mice that had risk factors for Alzheimer’s bred into them.

After repeated transfusions from healthy mice, the researchers reported that the formation of brain amyloid plaques in the transgenic mice modeling Alzheimer’s disease decreased between 40 and 80 percent.

In older animals with amyloid disease, the researchers observed an improvement in spatial memory ability and slower development of plaques.

The exact mechanism of how these blood transfusions may be impacting the formation of amyloid plaques is still unknown.

Nonetheless, Soto said he and his team were surprised by the magnitude of therapeutic benefit using this approach.

“In some of the animals we see up to 80 percent reduction of the damage in the brain,” he said. “We also saw that treated animals exhibited normal memory, whereas untreated animals have severe memory problems.”

“The amyloid plaque is seen in thin sections cut from the brain by using a microscope after treating the sections with special stains. It was first described in 1907 by Alois Alzheimer, a German psychiatrist and neuropathologist,” said Dr. Bibhuti Mishra, the chief of neurology at Long Island Jewish Forest Hills in Queens, part of Northwell Health in New York.

Mishra told Healthline that Alzheimer first discovered these plaques of “darkly stained substance” in the brain of a 51-year-old woman who died after an illness characterized by progressive loss of all cognitive functions.

Alzheimer also reported tangles of branches of nerve fibers, or “neurofibrillary tangles,” also associated with these symptoms.

“Since then, hundreds of researchers have confirmed both these descriptions in those who die after an illness similar to the first patient described by Alzheimer,” Mishra noted.

Soto emphasized that studies using mouse models are a necessary first step to analyze the efficacy of a therapeutic strategy.

“Of course, mice are not humans, so we would need to show that our approach works in ‘real life’ with ‘real patients,’” he explained. “Whole blood exchange, as we did in this study, is not feasible in humans.”

However, he added that there are two technologies currently in common medical practice that may work — plasmapheresis, also called therapeutic plasma exchange, and blood dialysis.

“We are currently adapting these techniques for mice studies and if we obtain positive results, the next step will be to start some clinical trials in humans affected by [Alzheimer’s disease],” confirmed Soto.

Percy Griffin, Ph.D., the Alzheimer’s Association director of scientific engagement, said that given the similarities between mice and humans, the research offers a good model to quickly test ideas and targets before translating them into people.

“In this study, blood from young mice was able to reduce the deposition of amyloid, an Alzheimer’s-related brain change, and improve memory,” he told Healthline. “While this is exciting, more research is needed to understand what specific factors in young blood helps to reduce the Alzheimer’s-related brain changes.”

According to Mishra, this study raises many more questions than answers, but it still “may be a crucial step toward finding the treatment for Alzheimer’s Disease.”

Mishra pointed out that many researchers have evidence to support the generation and deposition of amyloid peptides, the substance that makes up amyloid plaques in the brain, without contribution from the blood.

“What proportion of the amyloid collection is contributed by the circulating amyloid peptides?” Mishra asked. “What starts the process of forming aggregates of amyloid peptides?”

He also wondered if it’s sufficient to focus on amyloid plaque alone and ignore other pathological abnormalities described by Alzheimer, such as neurofibrillary tangles.

Griffin said the Alzheimer’s Association is encouraged by the “diversity of therapeutic approaches” currently under investigation and is committed to diversifying the treatment pipeline through their Part the Cloud program.