While Alzheimer’s disease is widely known as a brain disorder, new research reveals it also affects other parts of the body.
In a study published in Neuron, scientists from Baylor College of Medicine and Texas Children’s Hospital used fruit flies to show that Alzheimer’s-related proteins don’t just damage the brain—they disrupt the health and function of many other organs too.
The research team, led by Dr. Hongjie Li and Dr. Hugo Bellen, created a detailed map called the Alzheimer’s Disease Fly Cell Atlas.
This atlas charts how different genes behave in over 200 types of cells throughout the bodies of fruit flies that had Alzheimer’s proteins in their brains.
It’s the first resource of its kind and offers a whole-body view of how Alzheimer’s-related changes can ripple far beyond the brain.
The study focused on two hallmark proteins of Alzheimer’s: Aβ42, the protein that forms sticky plaques, and Tau, which forms tangles inside brain cells. Researchers engineered fruit flies to produce either Aβ42 or Tau in only their neurons—the cells of the brain and nervous system—so they could see how these proteins affect the rest of the body without being present there directly.
The results were eye-opening.
Flies with Aβ42 in their neurons showed problems mainly in their nervous system, especially in sensory cells. Cells involved in smell, vision, and hearing were particularly affected.
This matches what doctors have seen in humans—loss of smell is one of the early warning signs of Alzheimer’s disease. In the flies, the team even identified the exact types of smell-sensing cells that became damaged by Aβ42.
In contrast, Tau had a wider impact across the body. Flies that produced Tau in their neurons showed changes in fat metabolism, digestion, and even fertility. These issues resemble age-related decline, suggesting that Tau might speed up the aging process, even outside the brain.
The researchers also found that communication between the brain and other organs was disrupted, possibly because Tau interfered with the nervous system’s ability to send signals throughout the body.
“Our findings show that Alzheimer’s-related proteins in the brain can trigger a chain reaction, harming tissues that don’t even produce these proteins,” said Dr. Tzu-Chiao Lu, one of the study’s first authors. “This helps explain why Alzheimer’s patients often experience problems that go beyond memory loss, such as weight loss or digestive issues.”
The Alzheimer’s Disease Fly Cell Atlas is now a valuable tool for scientists around the world. By showing how Alzheimer’s proteins affect different organs and cell types, it can guide future studies that aim to find new treatments or biomarkers—early signs of disease that show up outside the brain.
This research also highlights the importance of brain-body communication in neurodegenerative diseases. Understanding how signals break down between the brain and other organs could lead to more effective therapies that treat the whole body, not just the brain.
In the words of Dr. Bellen, “This work gives us a more complete picture of Alzheimer’s disease. It’s not just a brain disorder—it’s a condition that involves the entire body.”
If you care about Alzheimer’s disease, please read studies about the protective power of dietary antioxidants against Alzheimer’s, and eating habits linked to higher Alzheimer’s risk.
For more health information, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
The research findings can be found in Neuron.
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