Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cortex area thinner in youth with Alzheimer's-related gene

24.04.2007
A part of the brain first affected by Alzheimer’s disease is thinner in youth with a risk gene for the disorder, a brain imaging study by researchers at the National Institute of Mental Health (NIMH), one of the National Institutes of Health (NIH), has found.

A thinner entorhinal cortex, a structure in the lower middle part of the brain’s outer mantle, may render these youth more susceptible to degenerative changes and mental decline later in life, propose Drs. Philip Shaw, Judith Rapoport, Jay Giedd, and NIMH and McGill University colleagues. They report on how variation in the gene for apoliproprotein (ApoE), which plays a critical role in repair of brain cells, affects development of this learning and memory hub in the June, 2007 Lancet Neurology.

"People with the Alzheimer’s-related variant of the ApoE gene might not be able to sustain much aging-related tissue loss in the entorhinal cortex before they cross a critical threshold," explained Shaw. "But the early thinning appears to be a harmless genetic variation rather than a disease-related change, as it did not affect youths’ intellectual ability. Only long-term brain imaging studies of healthy aging adults will confirm whether this anatomical signature detectible in childhood predisposes for Alzheimer’s."

It was already known that adults destined to develop Alzheimer’s disease tend to have a smaller and less active entorhinal cortex. This structure is the first to shrink in volume and to develop the neurofibrillary tangles characteristic of the disorder.

Previous studies had also implicated in Alzheimer’s one of three versions of a gene that produces ApoE. The ApoE4 variant occurs in 10-25 percent of the general population, but in 40 percent of late-onset Alzheimer’s patients. The strongest genetic risk factor for the disease discovered to date, ApoE4 has been linked to altered brain activity in adults and impaired neuronal development.

... more about:
»APOE4 »Alzheimer »apoE »entorhinal

Shaw and colleagues suspected that youth with ApoE4 would have a thinner entorhinal cortex. To confirm this, they compared the MRI (magnetic resonance imaging) scans of 239 healthy children and teens with their ApoE gene types. Many were re-scanned as they grew up to see if there was any ongoing thinning process traceable to ApoE4.

Each individual inherits two copies of the ApoE gene, one from each parent. Youth with at least one copy of the relatively rare ApoE2 variant – which may confer a protective effect against developing Alzheimer’s – showed the thickest entorhinal cortex. This was the first evidence that the ApoE2 version, which is carried by 5-10 percent of the population, affects brain structure, say the researchers. Youth with two copies of ApoE3, the most common version (65-85% prevalence), had intermediate cortex thickness. Those with one or two copies of ApoE4 had the thinnest entorhinal cortex.

ApoE4 gene type also predicted thinning of two other brain regions (medial temporal and posterior orbitofrontal areas) affected early in Alzheimer’s disease, which, like the entorhinal cortex, are involved in learning and memory. The pattern of changes resembled that seen in early Alzheimer’s, but to a far lesser degree. For example, the entorhinal cortex thinning seen in Alzheimer’s disease is about 10-fold greater than in the youth with ApoE4.

Although they did not test for possible learning and memory deficits, the researchers found no difference in IQ attributable to ApoE gene type. Nor did the E4 variant accelerate loss of cortex tissue. The differences were fixed, and didn't progress. In fact, the researchers noted evidence that ApoE4 may even promote survival in infancy and protect the brain’s thinking capacity against damage from infectious illness.

"In the future we hope to determine whether this thinner cortex is associated with differences in brain activity during tasks of learning and memory in children," said Shaw.

Jules Asher | EurekAlert!
Further information:
http://www.nih.gov

Further reports about: APOE4 Alzheimer apoE entorhinal

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>