Scientists uncover kidney-to-brain route for Parkinson’s-related protein spread

Publication date: Jun 23, 2025

They examined kidney samples from patients with Parkinsons disease or related disorders, as well as from people with end-stage kidney disease who had no known brain conditions. But when kidney function is impaired, the protein can build up, deposit in the kidney itself, and travel to the brain via nerve pathways. The researchers also used genetically modified mice, normal wild-type mice, and mice with kidney failure to test how alpha-synuclein behaves in the body under different conditions. Most of the alpha-synuclein in the blood is found in red blood cells, and patients with kidney disease often have fragile or damaged red cells. But in mice with kidney failure, the protein stuck around longer in the blood and built up in the kidneys. Over the following months, they observed the protein moving along known nerve pathways from the kidney to the spinal cord and then into various brain regions. A new study published in Nature Neuroscience has uncovered evidence that Parkinsons disease and related conditions may start not in the brain, but in the kidneys.

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