A team of neurologists from Columbia University (USA) has discovered that the brain does not stop growing, a finding that could help treat degenerative diseases such as Alzheimer’s.
Previously, researchers believed that the brain did not develop any new cells after childhood, making it much more difficult for adults to acquire new skills or learn a foreign language, for example.
More recent studies suggested that if specific areas of the brain were hyperstimulated, new cells could form. However, a new study published in the journal Cell Stem Cell has concluded that thousands of new brain cells or neurons form all the time, even when people are very old.
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The work suggests that problems with age-related memory and mental abilities are not due to the loss of neurons, but rather to failures in the neurons themselves to communicate appropriately with each other.
“We found that older people have a similar ability to generate thousands of new hippocampal neurons from progenitor cells, as younger people do. However, older people had less vascularization (blood vessel formation) and perhaps less capacity of new neurons to establish connections “, explains Maura Boldrini, leader of the study.
This advance could help scientists better understand the causes of dementia and how to prevent it from occurring, as the numbers of people with these neurodegenerative disorders continue to increase.
For their experiment, the experts looked at the hippocampus in 28 healthy individuals between the ages of 14 and 79 who had died suddenly. None of them had cognitive impairment or depression, which can affect the development of neurons.
They found that even in the most mature brains neurons were forming up to the time of death. It is the first time that scientists have observed newly created neurons and the state of blood vessels throughout the human hippocampus shortly after death.
“We found similar numbers of intermediate neuronal progenitors and thousands of immature neurons,” the authors concluded.
The caveat in this case was that older people formed fewer new blood vessels within brain structures and possessed a smaller group of progenitor cells, descendants of stem cells that develop into neurons.
According to Boldrini, this brain deterioration in old age could be due to this smaller set of neural stem cells, the decrease in blood vessels and reduced cell-to-cell connectivity in the hippocampus.
“It is possible that ongoing hippocampal neurogenesis supports human-specific cognitive function throughout life and that the declines may be related to compromised cognitive-emotional resilience,” he concludes.
Reference: Cell Stem Cell, Boldrini et al .: “Human Hippocampal Neurogenesis Persists Throughout Aging” http://www.cell.com/cell-stem-cell/fulltext/S1934-5909(18)30121-8, DOI: 10.1016 /j.stem.2018.03.015
