N.B.: Different languages can express different contents  -  (Italiano - English)


Even older adults grow new brain cells (2018-05-08)

Researchers at Columbia University Vagelos College of Physicians and Surgeons show for the first time that healthy older men and women can generate just as many new brain cells as younger people.
But new neurons in older brains may make fewer connections.

Scientists present the most definitive evidence to date that the human brain makes new neurons throughout life.

There has been controversy over whether adult humans grow new neurons, and some research has previously suggested that the adult brain was hard-wired and that adults did not grow new neurons.

Lead author Maura Boldrini, associate professor of neurobiology at Columbia University, says the findings may suggest that many senior citizens remain more cognitively and emotionally intact than commonly believed.

"We found that older people have similar ability to make thousands of hippocampal new neurons from progenitor cells as younger people do," Boldrini says.

"We also found equivalent volumes of the hippocampus (a brain structure used for emotion and cognition) across ages.

Nevertheless, older individuals had less vascularization and maybe less ability of new neurons to make connections."

IMAGE - A newborn neuron (upper left) in the brain of an older adult. Image: Maura Boldrini / Columbia University Vagelos College of Physicians and Surgeons.

The researchers autopsied hippocampi from 28 previously healthy individuals aged 14-79 who had died suddenly.

This is the first time researchers looked at newly formed neurons and the state of blood vessels within the entire human hippocampus soon after death.

The researchers had determined that study subjects were not cognitively impaired and had not suffered from depression or taken antidepressants, which Boldrini and colleagues had previously found could impact the production of new brain cells.

In rodents and primates, the ability to generate new hippocampal cells declines with age.

Waning production of neurons and an overall shrinking of the dentate gyrus, part of the hippocampus thought to help form new episodic memories, was believed to occur in aging humans as well.

IMAGE - A neural stem cell in the brain. Image: Maura Boldrini / Columbia University Vagelos College of Physicians and Surgeons.

The researchers from Columbia University and New York State Psychiatric Institute found that even the oldest brains they studied produced new brain cells.
"We found similar numbers of intermediate neural progenitors and thousands of immature neurons," they wrote.

Nevertheless, older individuals form fewer new blood vessels within brain structures and possess a smaller pool of progenitor cells-descendants of stem cells that are more constrained in their capacity to differentiate and self-renew.

The results point to a new model of brain aging, in which older brains retain the ability to make new neurons but may become less able to form new connections between them and keep them supplied with oxygen.

“It is possible that the changes we see in the older brains are related to some cognitive-emotional changes that occur with aging,” Boldrini said, “and exercise, diet, and medications may help, but future studies are needed to investigate these ideas.”

For more information

Cell Stem Cell
Human Hippocampal Neurogenesis Persists Throughout Aging
Maura Boldrini, Camille A. Fulmore, Alexandria N. Tartt, Laika R. Simeon, Ina Pavlova, Verica Poposka, Gorazd B. Rosoklija, Aleksandar Stankov, Victoria Arango, Andrew J. Dwork, René Hen, J. John Mann.