A new study in mice suggests that the answer may be yes. As Science News reports, researchers have found evidence that the immune response involved in Alzheimer’s-related brain damage may be partly organised in the lymph nodes — small structures throughout the body that help coordinate the immune system.
The research, published in Nature Neuroscience, offers a new perspective on how brain damage may develop in Alzheimer’s disease.
Scientists have long known that Alzheimer’s involves more than the accumulation of abnormal proteins in the brain. The immune system also becomes active, producing inflammation that can contribute to damage to brain cells. What has been less clear is how immune cells outside the brain might become involved.
The researchers found that proteins associated with brain damage can travel from the brain to nearby lymph nodes. There, they can trigger an immune response. Some of the activated immune cells can then travel back towards the brain, where they were associated with inflammation and damage to brain tissue.
The researchers were able to reduce this damage in mice by blocking part of this immune response. Interestingly, this did not prevent the accumulation of tau, a protein strongly associated with Alzheimer’s and other neurodegenerative diseases. Instead, it reduced the amount of damage to brain tissue.
This distinction could be important. It suggests that the abnormal proteins themselves may not tell the whole story. The way the immune system responds to them could also influence how much damage the brain eventually experiences.
The findings may eventually open the door to new approaches to treatment. Rather than focusing exclusively on what happens inside the brain, researchers could potentially target parts of the immune response elsewhere in the body. This could be particularly interesting because the blood-brain barrier makes it difficult for many medicines to reach the brain.
There is still a long way to go. The study was conducted in mice, and further research will be needed to determine whether the same mechanism occurs in people with Alzheimer’s disease.
For now, the study does not suggest that Alzheimer’s disease begins in the lymph nodes. Instead, it points to a possible connection between what happens in the brain and how the immune system responds elsewhere in the body.
As Science News highlights, understanding this connection could help researchers look at Alzheimer’s from a different angle: not only as a disease of the brain, but also as a condition involving communication between the brain and the immune system.
PhD in Sociology from the University of Barcelona. Early Childhood Education Teacher. Substitute Teacher at the Universitat de València.