Archive for the ‘Washington University’ Category


While the brain sleeps, it clears out harmful toxins, a process that may reduce the risk of Alzheimer’s, researchers say.

During sleep, the flow of cerebrospinal fluid in the brain increases dramatically, washing away harmful waste proteins that build up between brain cells during waking hours, a study of mice found.

“It’s like a dishwasher,” says Dr. Maiken Nedergaard, a professor of neurosurgery at the University of Rochester and an author of the study in Science.

The results appear to offer the best explanation yet of why animals and people need sleep. If this proves to be true in humans as well, it could help explain a mysterious association between sleep disorders and brain diseases, including Alzheimer’s.

Nedergaard and a team of scientists discovered the cleaning process while studying the brains of sleeping mice. The scientists noticed that during sleep, the system that circulates cerebrospinal fluid through the brain and nervous system was “pumping fluid into the brain and removing fluid from the brain in a very rapid pace,” Nedergaard says.

The team discovered that this increased flow was possible in part because when mice went to sleep, their brain cells actually shrank, making it easier for fluid to circulate. When an animal woke up, the brain cells enlarged again and the flow between cells slowed to a trickle. “It’s almost like opening and closing a faucet,” Nedergaard says. “It’s that dramatic.”

Nedergaard’s team, which is funded by the National Institute of Neurological Disorders and Stroke, had previously shown that this fluid was carrying away waste products that build up in the spaces between brain cells.

The process is important because what’s getting washed away during sleep are waste proteins that are toxic to brain cells, Nedergaard says. This could explain why we don’t think clearly after a sleepless night and why a prolonged lack of sleep can actually kill an animal or a person, she says.

So why doesn’t the brain do this sort of housekeeping all the time? Nedergaard thinks it’s because cleaning takes a lot of energy. “It’s probably not possible for the brain to both clean itself and at the same time [be] aware of the surroundings and talk and move and so on,” she says.

The brain-cleaning process has been observed in rats and baboons, but not yet in humans, Nedergaard says. Even so, it could offer a new way of understanding human brain diseases including Alzheimer’s. That’s because one of the waste products removed from the brain during sleep is beta amyloid, the substance that forms sticky plaques associated with the disease.

That’s probably not a coincidence, Nedergaard says. “Isn’t it interesting that Alzheimer’s and all other diseases associated with dementia, they are linked to sleep disorders,” she says.

Researchers who study Alzheimer’s say Nedergaard’s research could help explain a number of recent findings related to sleep. One of these involves how sleep affects levels of beta amyloid, says Randall Bateman, a professor of neurology Washington University in St. Louis who wasn’t involved in the study.

“Beta amyloid concentrations continue to increase while a person is awake,” Bateman says. “And then after people go to sleep that concentration of beta amyloid decreases. This report provides a beautiful mechanism by which this may be happening.”

The report also offers a tantalizing hint of a new approach to Alzheimer’s prevention, Bateman says. “It does raise the possibility that one might be able to actually control sleep in a way to improve the clearance of beta amyloid and help prevent amyloidosis that we think can lead to Alzheimer’s disease.”

Thanks to Kebmodee for bringing this to the It’s Interesting community.


Designer Lamm’s depiction of how the human face might look in 100,000 years

We’ve come along way looks-wise from our homo sapien ancestors. Between 800,000 and 200,000 years ago, for instance, rapid changes in Earth climate coincided with a tripling in the size of the human brain and skull, leading to a flattening of the face. But how might the physiological features of human beings change in the future, especially as new, wearable technology like Google Glass change the way we use our bodies and faces? Artist and researcher Nickolay Lamm has partnered with a computational geneticist to research and illustrate what we might look like 20,000 years in the future, as well as 60,000 years and 100,000 years out. His full, eye-popping illustrations are at the bottom of this post.

Lamm says this is “one possible timeline,” where, thanks to zygotic genome engineering technology, our future selves would have the ability to control human biology and human evolution in much the same way we control electrons today.

Lamm speaks of “wresting control” of the human form from natural evolution and bending human biology to suit our needs. The illustrations were inspired by conversations with Dr. Alan Kwan, who holds a PhD in computational genomics from Washington University.

Kwan based his predictions on what living environments might look like in the future, climate and technological advancements. One of the big changes will be a larger forehead, Kwan predicts – a feature that has already expanding since the 14th and 16th centuries. Scientists writing in the British Dental Journal have suggested that skull-measurement comparisons from that time show modern-day people have less prominent facial features but higher foreheads, and Kwan expects the human head to trend larger to accommodate a larger brain.

Kwan says that 60,000 years from now, our ability to control the human genome will also make the effect of evolution on our facial features moot. As genetic engineering becomes the norm, “the fate of the human face will be increasingly determined by human tastes,” he says in a research document. Eyes will meanwhile get larger, as attempts to colonize Earth’s solar system and beyond see people living in the dimmer environments of colonies further away from the Sun than Earth. Similarly, skin will become more pigmented to lesson the damage from harmful UV radiation outside of the Earth’s protective ozone. Kwan expects people to have thicker eyelids and a more pronounced superciliary arch (the smooth, frontal bone of the skull under the brow), to deal with the effects of low gravity.

The remaining 40,000 years, or 100,000 years from now, Kwan believes the human face will reflect “total mastery over human morphological genetics. This human face will be heavily biased towards features that humans find fundamentally appealing: strong, regal lines, straight nose, intense eyes, and placement of facial features that adhere to the golden ratio and left/right perfect symmetry,” he says.

Eyes will seem “unnervingly large” — as least from our viewpoint today — and will feature eye-shine and even a sideways blink from the re-introduced plica semilunaris to further protect from cosmic ray effects.

There will be other functional necessities: larger nostrils for easier breathing in off-planet environments, denser hair to contain heat loss from a larger head — features which people may have to weigh up against their tastes for what’s genetically trendy at the time. Instead of just debating what to name a child as new parents do today, they might also have to decide if they want their children to carry the most natural expression of a couple’s DNA, such as their eye-color, teeth and other features they can genetically alter.

Excessive Borg-like technological implants would start to become untrendy, though, as people start to increasingly value that which makes us look naturally human. That “will be ever more important to us in an age where we have the ability to determine any feature,” Kwan says.

Wearable technology will still be around, but in far more subtle forms. Instead of Google Glass and iWatch, people will seek discrete implants that preserve the natural human look – think communication lenses (a technologically souped up version of today’s contacts) and miniature bone-conduction devices implanted above the ear. These might have imbedded nano-chips that communicate to another separate device to chat with others or for entertainment.

The bird’s eye view of human beings in 100,000 years will be people who want to be wirelessly plugged in, Kwan says, but with minimal disruption to what may then be perceived as the “perfect” human face.

His Predictions:

In 20,000 years: Humans have a larger head with a forehead that is subtly too large. A future “communications lens” will be manifested as a the yellow ring around their eyes. These lenses will be the ‘Google Glass’ of the future.

In 60,000 years: Human beings have even larger heads, larger eyes and pigmented skin. A pronounced superciliary arch makes for a darker area below eyebrows. Miniature bone-conduction devices may be implanted above the ear now to work with communications lenses.

In 100,000 years: The human face is proportioned to the ‘golden ratio,’ though it features unnervingly large eyes. There is green “eye shine” from the tapetum lucidum, and a more pronounced superciliary arch. A sideways blink of the reintroduced plica semilunaris seen in the light gray areas of the eyes, while miniature bone-conduction devices implanted above the ear work with the communications lenses on the eyes.

Thanks to Ray Gaudette for bringing this to the attention of the It’s Interesting community.


There’s more to malnutrition than poor diet. Two complementary studies suggest that microbes have an important role to play in both the onset and treatment of a poorly understood form of malnutrition called kwashiorkor.

Malnutrition, the leading cause of death among children worldwide, remains something of a puzzle. It is unclear, for instance, why some children are especially prone to becoming malnourished when siblings they live with appear to fare better.

Now Jeffrey Gordon at Washington University in St Louis, Missouri, and his colleagues have found that a child’s risk of malnutrition may come down to the microbes in his or her guts.

Working in southern Malawi, the team identified sets of identical and non-identical twins in which one child had kwashiorkor – thought to be caused by a lack of protein – and the other did not, despite the shared genetics and diet. Gordon’s team took faecal samples from three sets of twins and transplanted the samples into the guts of mice, which were then fed a typical nutrient-poor Malawian diet.

Mouse weight lossAll of the mice lost some weight. However, some lost significantly more weight, and more quickly, than others. Further investigation showed that these mice had all received a faecal sample from children with kwashiorkor.

The finding strongly hinted that the mice had picked up a kwashiorkor-like condition from the microbes within the faecal implant, so the researchers studied the rodents’ gut flora. They found higher than normal levels of bacteria associated with illnesses such as inflammatory bowel disease.

The results suggest pathogenic microbes may heighten the problems of malnutrition in some children, says Jeremy Nicholson at Imperial College London, a member of the study team. “There’s a lot of work revolving around obesogenesis – how given a standard diet one set of bugs might make more calories available than another set,” he says. “But the other side of that coin is that maybe particular bugs can restrict calorie availability and exacerbate a poor diet.”

Indi Trehan at Washington University, another member of the research team, agrees. “I think it is correct that there are more factors than simple food insecurity at play in terms of malnutrition,” he says.

Antibiotic aidTrehan is lead author on a second new study, which examines how children with kwashiorkor respond when given nutrient-rich therapeutic diets. Trehan’s team found that the children were significantly less likely to become malnourished once the dietary treatment had ended if they were given a course of antibiotics along with the diet.

Together, the studies help us understand the role that infections might play in malnutrition, says Trehan. This might point towards a future in which microbial concoctions can be tailored to guard against such infections and treat specific conditions, suggests Nicholson.

Alexander Khoruts at the University of Minnesota in Minneapolis has been using faecal transplants to treat resistant Clostridium difficile disease in humans. “It is likely that microbiota are involved in pathogenesis of many other diseases, and it is possible that faecal transplants may be an approach to treat those as well,” he says. But because gut bacteria are so complex, he thinks more research will be needed to develop appropriate microbe-based therapies.