Here’s yet another reason to get a good night’s rest: Researchers have found a link between the lack of sleep and the development of Alzheimer’s in mice.
The researchers studied levels of amyloid beta — a protein that accumulates in the brain of people with Alzheimer’s — in mice genetically engineered to have a version of Alzheimer’s disease. Amyloid levels rose in the brain when the mice were awake, and fell when they slept. When the researchers prevented the mice from sleeping, it made matters worse [Reuters]. Sleep deprivation accelerated the formation of plaques made of amyloid beta, they found.
The study, published in Science, may lead to other studies that examine whether people with chronic sleep problems are more likely to develop Alzheimer’s. Says lead researcher Jae-Eun Kang: “The hope would be to show that treating sleep problems in humans is important not just for the immediate effect of having a normal life, but also for the long-term effect of having a healthier brain” [Bloomberg].
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A new study based on neurological data and brain specimens from a group of nuns, known as the Nun Study, confirms that language skills earlier in life are linked to Alzheimer’s disease risk in older age. But it also adds new, puzzling information to our knowledge about the disease: The brains of the women who did not have Alzheimer’s symptoms had larger brain cells, or neurons, but not necessarily fewer of the plaques and tangles characteristic of the disease.
To assess language skills early in life, researchers examined essays written by 14 women when they entered the convent, looking for the number of ideas expressed in every group of 10 words. A previous study linked grammatically complex writing skills to a decreased risk of dementia, and this study confirmed it: The essays written by women who maintained their memory scored 20 percent higher on language tests. “This is the second independent sample with the same result. We’re back to the metaphor of the brain as a computer and a muscle,” said [geriatric psychiatrist] Dr. Gary J. Kennedy…. “In volunteers who had no signs of Alzheimer’s but did have the plaques and tangles, the neurons were actually larger and more functional with more connections” [U.S. News and World Report].
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Inserting a “pacemaker” into the brain to emit regular pulses of electricity and quell disordered neural activity may sound like a therapy of last resort, but if current experiments show beneficial results the brain surgery may one day be commonplace. But some scientists are cautioning that research on so-called deep brain stimulation may be pressing ahead too quickly, and warn that long-term effects of the surgery are not yet clear.
A growing number of psychiatric researchers are testing the method’s effectiveness on a host of psychiatric disorders. Until recently, deep brain stimulation was approved in the U.S. only to treat certain movement disorders, primarily those of Parkinson’s disease, for which it diminishes tremors and rigidity and improves mobility. To date, more than 60,000 patients worldwide have had the devices implanted [Los Angeles Times]. But now large clinical trials are in the works that will test the use of deep brain stimulation for obsessive compulsive disorder, epilepsy, and depression. Smaller experiments are beginning to assess the therapy’s effectiveness on a wide range of disorders including anorexia, drug addiction, obesity, traumatic brain injury, and Alzheimer’s.
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Young adults with a genetic variant that increases their chance of developing Alzheimer’s later in life also have increased activity in the section of their brain devoted to memory, a new study has found. Researchers say the results suggest that the memory portion of the brain, the hippocampus, may eventually get worn out from a lifetime of overuse.
Researchers conducted fMRI brain scans of 36 volunteers, half of whom had at least one copy of the gene, known as APOE4. “We were surprised to see that even when the volunteers carrying APOE4 weren’t being asked to do anything, you could see the memory part of the brain working harder than it was in the other volunteers,” [study coauthor Christian] Beckmann said…. “Not all APOE4 carriers go on to develop Alzheimer’s, but it would make sense if in some people, the memory part of the brain effectively becomes exhausted from overwork and this contributes to the disease” [Reuters].
However, the researchers note that they’re far from proving this hypothesis, and say that it’s impossible to tell whether the extra activity contributes to Alzheimer’s symptoms later on or is just a sign of inefficient brain circuitry in the hippocampus [New Scientist].
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Spikes in blood sugar levels seem to be linked to memory problems, and may be a major factor in the normal memory and cognitive problems that crop up as people age, according to a new study. People’s ability to regulate blood sugar begins to deteriorate by their third or fourth decade and continues to decline, so older people are more prone to these sugar spikes. “This would suggest that anything to improve regulation of blood glucose would potentially be a way to ameliorate age-related memory decline,” said senior study author Dr. Scott Small…. The findings may also help explain why people who exercise don’t have as many cognitive problems as they age: Exercise helps stabilize blood glucose levels [HealthDay News].
The findings have important implications for the increasing number of overweight children who are at risk of diabetes, commented neuroscientist Bruce McEwen. “When we think about diabetes, we think about heart disease and all the consequences for the rest of the body, but we usually don’t think about the brain,” he said. “This is something we’ve got to be really worried about. We need to think about their ultimate risks not only for cardiovascular disease and metabolic disorders, but also about their cognitive skills, and whether they will be able to keep up with the demands of education and a fast-paced complex society. That’s the part that scares the heck out of me” [The New York Times].
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Contrary to conventional wisdom, marijuana may actually fight memory loss, scientists report—but only if taken in small doses amounting to just one puff a day. Researchers tested a compound similar to THC, the main psychoactive substance in marijuana, on rats and found that the chemical reduces inflammation in the brain and promotes the growth of new brain cells. Elderly rats given the compound performed better on learning and memory tasks. “Could people smoke marijuana to prevent Alzheimer’s disease if the disease is in their family? said [researcher Gary Wenk]. “We’re not saying that, but it might actually work” [Telegraph].
In one part of the study, researchers injected the THC-mimicking drug, called WIN-55212-2, into young rats with inflammation in their brains. The drug reduced inflammation. In a second part, the researchers injected WIN into older rats that were then put into a swimming tank with hidden resting spots. The medicated rats were better able to find and remember the resting spots. Dissection of the rat brains revealed not only reduced inflammation but the growth of new neurons. The results were presented at last week’s Society of Neuroscience meeting.
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The germ-fighting power of bleach lies in its ability to unravel cellular proteins, according to a new study. Researchers at the University of Michigan report that the active ingredient in bleach, hypochlorous acid, irreparably alters the three-dimensional structure of proteins in living cells—to fatal effect. They also found that some bacteria possess a special protein that can somewhat counter the ravages of hypochlorous acid. The findings clear up a hitherto murky understanding of how the common household cleaner does its job. “Everyone knew that bleached worked, and that was enough,” says [researcher Ursula Jacob]. “Few really cared how it worked” [Nature News].
In fact, Jacob’s team didn’t set out to answer that question either. They were studying a bacterial protein known as heat shock protein 33 (Hsp33) that helps other proteins maintain their proper shapes. Hsp33 is activated in times of stress, such as when the bacteria is exposed to high temperatures. “At high temperatures, proteins begin to lose their three-dimensional molecular structure and start to clump together and form large, insoluble aggregates, just like when you boil an egg,” said study lead author Jeannette Winter… Like a boiled egg, those proteins can never revert to their previous state, and the stressed cells eventually die [LiveScience.com].
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The European Commission has proposed a ban on medical research performed on our species’ closest relatives, the great apes. The pan-European initiative would extend a ban already in force in Austria, Great Britain, the Netherlands, and Sweden across the entire 27-member bloc. The ban, however, would not greatly affect current research, because no testing has been carried out on great apes in the EU for the past six years [The Scientist]. Nevertheless, the proposal [pdf] has received mixed reviews from both the scientific community, who fear excessive red tape, and animal rights groups, who say the ban does not go far enough.
If approved, the ban would prohibit researchers from using great apes, including chimpanzees, bonobos, gorillas, and orangutans, to test scientific “procedures,” although behavioral studies will still be allowed. There will also be exceptions for research that could save a great ape species threatened with extinction and in the case of a serious pandemic that affects humans. The proposal also affects research on other animals, stressing the “3Rs” of reducing the number of animals used, refining techniques to lessen pain and discomfort, and replacing animal studies with alternatives [ScienceNOW Daily News]. Some 12 million vertebrate animals are used each year in experiments throughout the 27-nation bloc — half for drug development and testing, a third for biology studies and the rest for cosmetics tests, toxicology and disease diagnosis [Reuters].
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While the nation decides on the fate of Barack Obama and John McCain tomorrow, residents of Michigan will also decide on the fate of thousands of human embryos. They will be voting on Proposition 2, an amendment to the state constitution that would lift a 30-year-old ban on the destruction of human embryos to get stem cells for medical research. Currently, researchers in the state must import embryonic stem cell lines from other states or countries. (Research on embryonic stem cells is legal in Michigan, but not the destruction of embryos.) The nationwide ban on federal funding for most embryonic stem cell research, instituted in 2001, will still hold, although both Obama and McCain have stated they would lift the ban if elected.
Proposition 2 pits the state’s powerful public and private biological research centers against large, conservative Catholic and evangelical populations who oppose destroying embryos, a form of human life [Wall Street Journal]. The proposition is sponsored by the bipartisan group Cure Michigan. Proponents argue embryos in fertility clinics are routinely thrown away, so why not donate them to science [Detroit Free Press]? The U. S. currently has 400,000 frozen embryos in storage, most of which will be discarded. Supporters say embryonic stem cell research could lead to therapies for degenerative diseases like Alzheimer’s and juvenile diabetes, and that lifting the ban would advance the state’s biomedical industry and create thousands of new jobs.
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Researchers have built a “biological brain” for a robot using a dish full of rat neurons, and have harnessed the neurons’ electric signals to navigate the robot around a pen. Researchers say the experiment should add to their understanding of how brain cells function, and could provide insight into what goes wrong in neurons affected by diseases like Alzheimer’s and Parkinson’s.
The robot’s controller nestles inside a small pot containing a pink broth of nutrients and antibiotics. Inside that pot, some 300,000 rat neurons have made – and continue to make – connections with each other. As they do so, the disembodied neurons are communicating, sending electrical signals to one another just as they do in a living creature [New Scientist]. The neurons’ automatic drive to connect and communicate may be an indication of how sturdy brain cells are; researcher Steve Potter, who has been involved in similar experiments, says that brain cells have “evolved to reconnect under almost any circumstance that doesn’t kill them” [Telegraph].
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Researchers have tested a new pharmaceutical approach to combating Alzheimer’s, and say they may have found the breakthrough drug that can halt the progress of the disease. In a small clinical trial, researchers tested a drug that targets the tangles of protein that form in the brain cells of Alzheimer’s patients, and found that the drug stopped the cognitive decline of those patients.
Lead researcher Claude Wischik says: “This is an unprecedented result in the treatment of Alzheimer’s disease. We have demonstrated for the first time that it may [be] possible to arrest the progression of this disease by targeting the tangles which are highly correlated with the disease” [CNN]. The results were announced at the International Conference on Alzheimer’s Disease taking place in Chicago.
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The cholesterol-lowering drugs known as statins are already one of the most commonly prescribed medications, taken by 15 million Americans in an attempt to ward off heart disease. Now, a new study suggests that the drugs may also reduce the risk of Alzheimer’s and dementia by 50 percent.
While the provocative finding offers hope that the cholesterol-reducing drugs might help against Alzheimer’s disease and other forms of dementia, scientists say this study is unlikely to be the last word on the topic. Indeed, it may just fuel an already lively debate over statins’ potential effect on dementia. Some research has hinted at benefits, while other studies, particularly in people with clear signs of Alzheimer’s disease, show no effect from the drugs [Science News].
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Researchers have caught sight of Alzheimer’s-like plaques in the brains of rabbits using a conventional MRI scan, in what could be an important step towards early detection of Alzheimer’s in humans. Researchers say that an earlier, easier diagnosis of the disease would allow patients to try more drugs and other therapies that could slow the progress of dementia.
Diagnosis by a commonly available clinical MRI scan would be a vast improvement over current methods. Many tools are used to look for signs of Alzheimer’s, including a battery of cognitive and behavioral tests… and imaging studies called PET scans that require the injection of special chemicals that help light up the brain. But doctors can make a definitive diagnosis only after a patient dies by identifying the presence of brain lesions called amyloid plaques [USA Today].
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In a day of mixed results for Alzheimer’s research, researchers found that an experimental vaccine failed to prevent the disease’s crippling dementia, but also noted that a drug once used to treat hayfever “significantly” improves the symptoms of memory loss. The two separate studies were both published in the Lancet [subscription required], and offer a telling reminder that in medical research progress against a disease is rarely straightforward.
The first study treated patients who had already been diagnosed with Alzheimer’s with a vaccine that targeted the protein plaques that clump around brain cells in increasing numbers as Alzheimer’s progresses. The theory was that dementia could be slowed or reversed once the plaques were cleared [HealthDay News]. However, the vaccine had no effect on the patients’ slide into dementia, despite the fact that autopsies of patients who died during the study showed that the plaques had largely vanished.
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Researchers have made a map of the human brain that shows a dense network of connections at the top of the cerebral cortex, suggesting that electrical signals travel through this hub on their way to more specialized regions. “This is just about the coolest paper I’ve seen in a long time, and forward-looking in terms of where the science is going,” said Dr. Marcus E. Raichle, a professor of neurology and radiology… who was not involved in the research. He added, “They’ve found in the brain what looks like a hub map of the airline system for the United States” [The New York Times].
An international team of researchers used a technique called diffusion spectrum imaging to map the connections between different parts of the brain. The technique traces the path of water moving along axons, long fibers that extend from a neuron’s main body and carry electrical signals [Science News]. They found the most connections at the top of the cortex along the crack that separates the brain’s two hemispheres. According to researchers, that area is not only a relay station, it’s also the area that’s most active when the brain is in “default mode,” the activation state present when the brain is not engaged in any specific cognitive task [The Scientist].
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