Rare young-like neurons may help some brains withstand Alzheimer’s
A Dutch study links Alzheimer’s resilience to survival programs in immature neurons found in the aging hippocampus.
By Lucas Ferreira · Science & Environment Writer
3 min read
Researchers in the Netherlands say a rare class of young-like brain cells may help explain why some people with Alzheimer’s-related brain changes avoid dementia. The finding matters because it points Alzheimer’s research toward natural defenses that may protect memory even after disease pathology is present.
The Netherlands Institute for Neuroscience-KNAW said the study examined cognitive resilience, the ability of some brains to keep working despite biological signs of Alzheimer’s disease. Senior author Evgenia Salta said about 30% of older adults who develop Alzheimer’s disease do not show symptoms, a gap researchers have not been able to explain.
The work, published in Cell Stem Cell, focused on immature neurons in the hippocampus, a memory-related region of the brain. These cells resemble developing neurons and are tied to the broader question of adult neurogenesis, the generation of new neurons in adulthood.
Brain bank tissue offered a comparison
Salta and colleagues studied donated human brain tissue from the Netherlands Brain Bank, according to the institute. The samples came from healthy people, people diagnosed with Alzheimer’s disease, and people whose brains showed Alzheimer’s pathology but who had not developed dementia.
The researchers concentrated on a small area of the hippocampus where immature neurons were expected to be found. Salta said the cells are very rare, so the team developed methods to locate them and used newer analytical approaches designed for human tissue rather than relying mainly on animal-study assumptions.
The team found immature neurons in all groups, including people whose average age was above 80, the institute said. That result supports the view that such cells can persist into very old age.
Cell activity, not cell count, stood out
The main difference was not that resilient people had far more of the cells, according to the researchers. The study instead found differences in the activity patterns of those cells.
In people who stayed cognitively resilient, the immature neurons appeared to turn on programs linked to survival and coping with damage, Salta said. The researchers also saw lower signals associated with inflammation and cell death in those individuals.
That suggests the cells may do more than serve as replacements for neurons lost to disease, according to Salta. She said they may help support nearby tissue and contribute to keeping the brain functional, though she cautioned that this remains a hypothesis.
The study has limits. Because it used donated tissue, the scientists could not watch the cells operate in living brains. Salta said the team inferred cell function from the data but could not confirm it directly with this type of research.
A lead, not a full explanation
The institute said the findings add one piece to a wider effort to understand why Alzheimer’s pathology leads to dementia in some people and not in others. Salta said resilience is unlikely to come from a single cause.
Future work will examine how immature neurons communicate with other brain cells and whether those interactions help preserve memory and thinking. The study does not show why the cells behave differently in resilient brains, but it gives researchers a target for studying the brain’s own protective responses.
Salta said understanding what shields these brains could eventually guide new therapeutic strategies. For now, the findings support a shift in Alzheimer’s research toward studying why some brains tolerate damage as well as how the disease causes it.
This story draws on original reporting from ScienceDaily.