Posts tagged alzheimer's
Articles and news from the latest research reports.
Alzheimer’s triggered by “type three diabetes”
An unhealthy diet could lead to Alzheimer’s disease by triggering a form of insulin resistance dubbed “type three diabetes”, scientists claim.
Photo: Getty Images/Peter Macdiarmid
High levels of the hormone insulin, brought on by a bad diet, may harm the brain in the same way that the muscle, liver and fat cells are affected by type two diabetes. Exposing the brain to too much insulin could cause it to stop responding to the hormone, hampering our ability to think and create new memories and ultimately leading to permanent damage, researchers said.
A diet high in fat and sugar has long been linked to a higher risk of Alzheimer’s, while studies of health among large populations have shown that a healthy Mediterranean diet may offer some protection. In type two diabetes, eating too much fatty and sugary food raises our insulin levels to such a consistently high degree that our muscles, fat and liver cells are no longer affected by the hormone.
This means that the amount of glucose and fat in our blood is allowed to increase unchecked, forcing the pancreas to produce even more insulin to try to cope. Ultimately it becomes exhausted and production drops to very low levels.
A small-scale trial on human patients at Washington University found that those who were given a nasal spray containing insulin were better at remembering details of stories, had longer attention spans and were more independent. A further trial on 240 volunteers showing early signs of dementia will provide further clues as to whether the spray can protect memory and learning ability and keep track of brain changes in patients.
A study on rats by experts from Brown University suggest that a similar process could affect the brain, which relies on insulin to regulate nerve signals related to memory and learning and to produce energy from glucose. Researchers found that blocking insulin from rats’ brains made them disorientated and unable to find their way out of a maze because they could not remember where they were.
Examination of their brains showed the same pattern of deterioration seen in Alzheimer’s patients, including increased levels of the amyloid plaque which is a key hallmark of the condition. If the theory is correct, it means eating more healthy foods and exercising more could reduce the risk of Alzheimer’s, and potentially reverse or slow down the memory loss in patients with the condition.
Dr Suzanne de la Monte, who led the study, told New Scientist magazine: “[The rats] were demented. They couldn’t learn or remember. “I believe [Alzheimer’s] starts with insulin resistance. If you can avoid brain diabetes you’ll be fine. But once it gets going you are going to need to attack on multiple fronts.”
(Source: telegraph.co.uk)
Researchers at Carnegie-Mellon University (CMU) are working with a Canadian startup called Autonomous ID to develop biometric shoes that can identify who you are by the way you walk.
The BioSoles can record the pressure points of someone’s feet, track their gait and use a microcomputer to compare that to a master file already made for that person. If the patterns match, the BioSoles stay silent. If they don’t, they transmit a wireless alarm message.
Since the devices are designed to detect changes in gait, some think they could end up being used to help spot early signs of Alzheimer’s disease.
Simple eye test could diagnose Alzheimer’s
The researchers from Lancaster University have found that those with the degenerative brain disease have difficulty with one particular test. They also found that the inability to carry out the tests in those who had already been diagnosed with Alzheimer’s was linked to lower memory function.
Photo: ALAMY
Dr Trevor Crawford said the latest results were potentially exciting. They showed, for the first time, a physical connection with the memory impairment that so often is the first noticeable symptom in Alzheimer’s.
Dr Crawford, of the department of Psychology and the Centre for Ageing Research, Lancaster University, said: “The diagnosis of Alzheimer’s disease is currently heavily dependent on the results of a series of lengthy neuropsychological tests.
"However, patients with a dementia often find that these tests are difficult to complete due to a lack of clear understanding and lapse in their attention or motivation.
"Over the last 10 years, researchers in laboratories around the world have been working on an alternative approach based on the brain’s control of the movements of the eye as a tool for investigating cognitive abilities, such as attention, cognitive inhibition and memory."
During the study, 18 patients with Alzheimer’s disease, 25 patients with Parkinson’s disease, 17 healthy young people and 18 healthy older people were asked to follow the movements of light on a computer monitor. In some instances they were asked to look away from the light. Detailed eye–tracking measurements showed stark contrasts in results.
Patients with Alzheimer’s made errors on the task when they were asked to look away from the light. They were unable correct those errors, despite being able to respond normally when they were asked to look towards the light.
These uncorrected errors were 10 times more frequent in the Alzheimers’ patients than the control groups. Researchers also measured memory function among those Alzheimer’s patients who found the test difficult and were able to show a clear correlation with lower memory function. Dr Crawford added: “The light tracking test could play a vital role in the diagnosis of Alzheimer’s.”
(Source: telegraph.co.uk)
Untangling the Mysteries of Alzheimer’s
ScienceDaily (Feb. 2, 2012) — One of the most distinctive signs of the development of Alzheimer’s disease is a change in the behavior of a protein that neuroscientists call tau. In normal brains, tau is present in individual units essential to neuron health. In the cells of Alzheimer’s brains, by contrast, tau proteins aggregate into twisted structures known as “neurofibrillary tangles.” These tangles are considered a hallmark of the disease, but their precise role in Alzheimer’s pathology has long been a point of contention among researchers.
Now, University of Texas Medical Branch at Galveston researchers have found new evidence that confirms the significance of tau to Alzheimer’s. Instead of focusing on tangles, however, their work highlights the intermediary steps between a single tau protein unit and a neurofibrillary tangle — assemblages of two, three, four, or more tau proteins known as “oligomers,” which they believe are the most toxic entities in Alzheimer’s.
"What we discovered is that there are smaller structures that form before the neurofibrillary tangles, and they are much more toxic than the big structures," said Rakez Kayed, UTMB assistant professor and senior author of a paper on the work now online in the FASEB Journal. “And we established that they were toxic in real human brains, which is important to developing an effective therapy.”
According to Kayed, a key antibody developed at UTMB called T22 enabled the team to produce a detailed portrait of tau oligomer behavior in human brain tissue. Specifically designed to bond only to tau oligomers (and not lone tau proteins or neurofibrillary tangles), the antibody made it possible for the researchers to use a variety of analytical tools to compare samples of Alzheimer’s brain with samples of age-matched healthy brain.
"One thing that’s remarkable about this research is that before we developed this antibody, people couldn’t even see tau oligomers in the brain," Kayed said. "With T22, we were able to thoroughly characterize them, and also study them in human brain cells."
Among the researchers’ most striking findings: in some of the Alzheimer’s brains they examined, tau oligomer levels were as much as four times as high as those found in age-matched control brains.
Other experiments revealed specific biochemical behavior and structures taken on by oligomers, and demonstrated their presence outside neurons — in particular, on the walls of blood vessels.
"We think this is going to make a big impact scientifically, because it opens up a lot of new areas to study," Kayed said. "It also relates to our main focus, developing a cure for Alzheimer’s. And I find that very, very exciting."
Provided by University of Texas Medical Branch at Galveston
Source: ScienceDaily