Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stem Cell Activity Deciphered in the Aging Brain

20.12.2006
Neurobiologists have discovered why the aging brain produces progressively fewer new nerve cells in its learning and memory center. The scientists said the finding, made in rodents, refutes current ideas on how long crucial "progenitor" stem cells persist in the aging brain.

The finding also suggests the possibility of treating various neurodegenerative disorders, including Alzheimer's disease, dementia and depression, by stimulating the brain's ability to produce new nerve cells, said senior study investigator Ashok K. Shetty, Ph.D., professor of neurosurgery at Duke University Medical Center and medical research scientist at Durham VA Medical Center.

Results of the study appear online in the journal Neurobiology of Aging. The research was funded by the National Institutes of Health and the U.S. Department of Veterans Affairs.

Previous studies by Shetty and others had demonstrated that as the brain ages, fewer new nerve cells, or neurons, are born in the hippocampus, the brain's learning and memory center. In one study, Shetty and colleagues showed that the production of new neurons in rats slows down dramatically by middle age -- the equivalent of 50 years in humans.

... more about:
»Hippocampus »Shetty »neurons »stem cells

But scientists did not know what causes this decline.

The common assumption had been that the brain drain was due to a decreasing supply of neural stem cells in the aging hippocampus, said lead study investigator Bharathi Hattiangady, Ph.D., research associate in neurosurgery. Neural stem cells are immature cells that have the ability to give rise to all types of nerve cells in the brain.

In the current study, however, the researchers found that the stem cells in aging brains are not reduced in number, but instead they divide less frequently, resulting in dramatic reductions in the addition of new neurons in the hippocampus.

To conduct their census, the researchers attached easy-to-spot fluorescent tags to the neuronal stem cells in the hippocampus in young, middle-aged and old rats.

They found that in young rats, the hippocampus contained 50,000 stem cells -- and, significantly, this number did not diminish with aging. This finding, the researchers said, suggested that the decreased production of new neurons in the aged brain was not due to a lack of starting material.

The researchers then used another fluorescent molecule to tag all stem cells that were undergoing division in the process of staying "fresh" in case they were recruited to become mature nerve cells.

They found that in young rats, approximately 25 percent of the neural stem cells were actively dividing, but only 8 percent of the cells in middle-aged rats and 4 percent in old rats were dividing. This decreased division of stem cells is what causes the decreased neurogenesis, or birth of nerve cells, seen with aging, the scientists said.

"This discovery provides a new avenue to pursue in trying to combat the cognitive decline associated with conditions such as Alzheimer's disease and with aging in general," Hattiangady said.

The team now is searching for ways to stimulate the brain to replace its own cells in order to improve learning and memory function in the elderly.

One approach being explored is to treat older rats with drugs designed to mimic the action of compounds called neurogenic factors, which encourage stem cells in the brain to divide, Shetty said. The researchers also are grafting neural stem cells grown in culture dishes into the hippocampus, to stimulate those already present. Additional approaches include using behavioral modification techniques, such as physical exercise and exposure to an enriching environment, that are known to stimulate proliferation of stem cells.

Marla Vacek Broadfoot | EurekAlert!
Further information:
http://www.duke.edu

Further reports about: Hippocampus Shetty neurons stem cells

More articles from Life Sciences:

nachricht Phagocytes versus killer cells - A closer look into the tumour tissue
21.10.2019 | Universität Duisburg-Essen

nachricht How intestinal cells renew themselves – the role of Klumpfuss in cell differentiation
21.10.2019 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

Im Focus: Novel Material for Shipbuilding

A new research project at the TH Mittelhessen focusses on the development of a novel light weight design concept for leisure boats and yachts. Professor Stephan Marzi from the THM Institute of Mechanics and Materials collaborates with Krake Catamarane, which is a shipyard located in Apolda, Thuringia.

The project is set up in an international cooperation with Professor Anders Biel from Karlstad University in Sweden and the Swedish company Lamera from...

Im Focus: Controlling superconducting regions within an exotic metal

Superconductivity has fascinated scientists for many years since it offers the potential to revolutionize current technologies. Materials only become superconductors - meaning that electrons can travel in them with no resistance - at very low temperatures. These days, this unique zero resistance superconductivity is commonly found in a number of technologies, such as magnetic resonance imaging (MRI).

Future technologies, however, will harness the total synchrony of electronic behavior in superconductors - a property called the phase. There is currently a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

Fraunhofer LBF and BAM develop faster procedure for flame-retardant plastics

21.10.2019 | Materials Sciences

For EVs with higher range: Take greater advantage of the potential offered by lightweight construction materials

21.10.2019 | Materials Sciences

Benefit and risk: Meta-analysis draws a heterogeneous picture of drug-coated balloon angioplasty

21.10.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>