The hippocampus is the region of the brain that plays an important role in the formation of specific, new memories, which is an ability that patients with Alzheimer's disease lose. The findings may have broad implications in determining how age, Alzheimer's disease and other diseases impact the function and integrity of the hippocampus.
Sudha Seshadri, MD, professor of neurology at BUSM, is a senior author of the study, which will be published online in Nature Genetics.
Previous research has shown that the hippocampus is one of the brain regions involved with short and long-term memory processes and that it shrinks with age. It also is one of the first regions to exhibit damage from Alzheimer's disease, which can cause memory problems and disorientation.
"One of the problems with studying the genetics of a disease like Alzheimer's, which becomes symptomatic later in life, is that many people die of other causes before they reach the age at which they might have manifested the clinical dementia associated with the disease," said Seshadri. "To get around this issue, we have been studying the genetics of traits that we know are associated with a high future risk of Alzheimer's disease but that can be measured in everyone, often 10 to 20 years before the age when most persons develop clinical symptoms."
The potential genetic traits are called endophenotypes, and hippocampal volume is one such trait. The hippocampus shrinks before and during the progression of Alzheimer's disease, but other factors, such as vascular risk factors and normal aging, also lead to the decrease in size.
"Our research team wanted to pinpoint the genetic causes of changes in the hippocampal volume in a sample of apparently normal older persons," said Seshadri.
The Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium allowed the researchers to gather data on hippocampal volume from 9,232 people who did not have dementia. They identified four genetic loci, including seven genes in or near these loci that appear to determine hippocampal volume.
The results show that if one of the genes is altered, the hippocampus is, on average, the same size as that of a person four to five years older. These results were replicated in two large European samples that included a mixed-age sample that included some participants with cognitive impairment.
"The findings indicate that these loci may have broad implications for determining the integrity of the hippocampus across a range of ages and cognitive capacities," said Seshadri. One of the genes identified by the researchers was also shown to play a role in memory performance in a different data sample.
The identified genetic associations indicate that certain genes could influence cell death by apoptosis, brain development and neuronal movement during brain development, and oxidative stress. Additionally, the researchers found that the genes play a role in ubiquitination, which is a process by which damaged proteins are removed, whereas other genes code for enzymes targeted by new diabetes medications.
"Future studies need to further explore these genetic regions in order to better understand the role of these genes in determining hippocampal volume," added Seshadri.
One of the largest cohorts involved in the study was the Framingham Heart Study cohort, affiliated with BUSM. Seshadri is a Senior Investigator at the Framingham Heart Study.
"Such important research would not be possible without the ongoing dedication of the Framingham study participants, which now span three generations and six decades," said Seshadri.
This study was funded primarily through the National Institute on Aging.
Jenny Eriksen | EurekAlert!
Making fuel out of thick air
08.12.2017 | DOE/Argonne National Laboratory
‘Spying’ on the hidden geometry of complex networks through machine intelligence
08.12.2017 | Technische Universität Dresden
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
11.12.2017 | Physics and Astronomy
11.12.2017 | Earth Sciences
11.12.2017 | Information Technology