These findings were described in the May 27 issue of Nature by Jaime Grutzendler, M.D., and colleagues. The study was supported by the National Institute on Aging (NIA), part of the National Institutes of Health.
Uninterrupted blood flow is critical for brain function, and the brain has developed various mechanisms to maintain it. Blockages in the smallest blood vessels can be cleared by processes that disintegrate or wash them out. However, not all blockages are cleared completely. Persistent blockage can reduce or stop blood flow, limiting the supply of oxygen and nutrients to the surrounding tissue and nerve cells. This, in turn, can lead to impaired communications between nerve cells and ultimately cell death.
The researchers used a newly developed imaging technique that can view the smallest blood vessels, known as microvessels, in the brains of living mice. They found that two to seven days after a blockage in brain microvessels, the cells lining the blood vessel wall engulf the remaining portion of the blockage, encapsulate it, seal it off from the interior of the blood vessel and finally expel the blocking material outside of the vessel. As a result of this process, blood flow is restored to the affected area. (See graphic below.)
"These are intriguing findings," said NIA Director Richard J. Hodes, M.D. "They open new avenues of basic research that may increase our understanding of how microvessels are maintained in the brain and throughout the body."
The research team demonstrated that this complex protective mechanism involves the activity of an enzyme, matrix metalloprotease 2/9, which breaks down large proteins and is known to play a role in blood vessel development and in stroke.
The researchers also found that the ability to move the blockage out of the blood vessel diminished with age. Young mice (age 4 months) were able to clear blockages more quickly and thoroughly than older mice (age 22 months). The incomplete removal of blockages in the brains of older mice led to a prolonged shortage of oxygen to the surrounding nerve cells and damaged the connections between nerve cells in the vicinity of the obstructed blood vessels.
"The reduced efficiency of this protective mechanism in the older brain and its effect on the function of nerve cells in the brain may significantly contribute to age-related cognitive decline," said Suzana Petanceska, Ph.D., of the Neurobiology of Aging Branch in NIA's Division of Neuroscience, which funded the research. "This may also be part of the mechanism by which vascular risk factors such as high blood pressure and diabetes increase the risk of Alzheimer's disease with age."
The NIA leads the federal effort supporting and conducting research on aging and the medical, social and behavioral issues of older people. For more information on research and aging, go to www.nia.nih.gov.
The NIH—The Nation's Medical Research Agency—includes 27 institutes and centers and is a component of the U. S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.
Barbara Cire | EurekAlert!
New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University
Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences