FDA Approves Ketamine Derivative as Depression Treatment for First Time

By Lee Hoffer, Case Western Reserve University | March 22, 2019 3:39 pm
One in 3 people with severe depression do not respond to treatment. (Credit: TZIDO SUN/Shutterstock)

One in 3 people with severe depression do not respond to treatment. (Credit: TZIDO SUN/Shutterstock)

Treatment-resistant depression affects 1 in 3 of the estimated 16.2 million adults in the U.S. who have suffered at least one major depressive episode. For them, two or more therapies have failed and the risk of suicide is much greater. It’s a grim prognosis.

There are few therapies for depression that resists treatment, which is why the FDA granted this new drug application Fast Track and Breakthrough Therapy status. On March 5, the Food and Drug Administration approved a new treatment called esketamine.


The chemical structure of esketamine.

On Feb. 12, 2019, I participated in the FDA review of this drug. Practically speaking, esketamine is essentially the same as ketamine, which is a pain killer with hallucinogenic effects and used illegally. As a member of the Drug Safety and Risk Management Advisory Committee of the FDA, I voted with the majority of that panel 14-2, to approve esketamine only for people who have treatment-resistant depression.


The chemical structure of ketamine.

For more than 20 years, I have researched illegal drug use and addiction. As a medical anthropologist, my work is oriented to understanding the perspectives and behaviors of people actively using illegal drugs. My research often involves fieldwork, which means participating in the lives of people as they go about their everyday routines. This has given me a personalized and practical outlook on illegal drug use. Many of the people I currently interview are heroin injectors who first started opioid use by misusing prescription drugs.

Not a Street Drug

But many drugs, especially those for the treatment of mental illness, have powerful effects on the central nervous system. How the drug is distributed and administered must minimize risk. What if the drug is addicting?

Some reports about esketamine have sensationalized this issue by referring to ketamine as a highly addictive street drug. In my research, this is not true. First, ketamine use is rare. The last time I interviewed a ketamine users was nearly 20 years ago and since its introduction in 1964, there have been no significant trends or outbreaks in its diversion or use.

Not all illegal drugs are sold “on the street.” Street drugs are staples of the illegal drug economy, which is run by drug trafficking organizations. Prescription opioids, heroin, cocaine, and marijuana are street drugs sold in open-air drug markets, where such markets exist. Hallucinogens and exotic, designer and other less popular drugs are rarely available in these settings. They simply do no appeal to enough users to make them profitable for drug traffickers to supply. Ketamine has always been in this second group. Why?

Is It Addictive?

Ketamine is short-acting – between two and four hours – and produces euphoria, sustained pain relief and sedation mixed with powerful hallucinogenic effects. Taking this drug can be very unpleasant. Out-of-body experiences, time perception distortions, tunnel vision and dissociation are common. These effects limit the popularity of ketamine and make it difficult to use habitually.

A person can take heroin everyday and function. Ketamine is disruptive.

Another reason that ketamine isn’t popular on the street is that users do not have to keep using it to avoid withdrawal. There is no withdrawal syndrome associated with ketamine; when people stop using it, they do not get sick. This is actually a benefit, because fear of withdrawal is often a major motivation for the continuation of drug use. Unlike street drugs, its appeal is limited and its addiction liability is comparatively low.

On balance, the profile of ketamine is more like LSD than cocaine or opioids. People do not get addicted. This does not mean that ketamine or esketamine is safe. Its access should be restricted and use monitored by a physician. The manufacturer is placing important restrictions on the drug. It will not be available at local pharmacies and never for take-home use. A person receiving the treatment, which was developed by Johnson & Johnson and delivered as a nasal spray, will be under observation and care of a health professional trained in the therapy. The drug will be given in an office or approved health center, and the patient will not be allowed to drive until the day after treatment.

Given its effectiveness and the proposed risk evaluation and mitigation strategy, the benefits outweigh the risks of esketamine for the treatment of depression that has not responded to other treatments. Like any new treatment, as manufacturers make this product available, monitoring it will be important to make sure the benefits outweigh the costs. People living with the misery of treatment-resistant depression need more options, and this drug should help.The Conversation


Lee Hoffer, Associate Professor of Anthropology; Professor of Psychiatry, Case Western Reserve University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

CATEGORIZED UNDER: Health & Medicine, Top Posts

From Popular Anesthetic to Antidepressant, Ketamine Isn’t the Drug You Think It Is

By Troy Farah | March 22, 2019 3:15 pm

A new form of ketamine, called esketamine was recently approved as a nasally-delivered antidepressant. (Credit: grey_and/Shutterstock)

An hour before we spoke, Darragh O’Carroll, an emergency room physician from Hawaii, had just given an elderly patient a sedating shot of ketamine. The man had pneumonia and was acting confused and fidgety, making him hard to treat.

“Not only it was a pain control for him when I was putting needles into his neck, but it also kept him still,” O’Carroll says. “And with very minimal risk of lowering his blood pressure.” Read More

This Woman Can Smell Parkinson’s. It Might Help Lead To Earlier Treatment

By Anna Groves | March 21, 2019 3:02 pm
joy milne

Joy Milne. (Credit: BBC/Youtube)

Parkinson’s disease stinks. Figuratively. But according to new research, it literally stinks too — to those who have a heightened sense of smell. Thanks to the help of one of these “super-smellers,” a team of scientists has identified subtle volatile compounds produced by Parkinson’s sufferers. These compounds could be used to make much easier, and earlier, diagnostics for the disease.

According to the CDC, Parkinson’s is the second-most common neurodegenerative disease after Alzheimer’s, and affects about 1% of the population at age 60, and 4% of the population by age 80. Current treatments can help alleviate some of the physical effects — like muscle tremors — though they don’t actually slow the progression of the disease. There is no cure.

Diagnosis is tricky, too: There’s no simple test. Once a patient has started to express some of the physical symptoms, it takes complicated brain imaging to confirm that certain brain cells — the neurons that produce dopamine — have been damaged or destroyed.

But a much simpler test might be on the way, according to recent research in ACS Science. Volatile compounds in sebum — the oily substance produced on your face and back — might soon be used to identify the disease.

Finding A Super Smeller

Lead author on the study, Perdita Barran, says she first learned about the “woman who can smell Parkinson’s” from her colleague Tito Kunath at the University of Edinburgh. He had given a public talk on his Parkinson’s research, and the woman was in the audience. As Barran tells it, “she got up at the end of [Kunath’s] presentation and said … ‘that’s all well and good that you’re doing this, but why aren’t you doing something about the fact that people with Parkinson’s smell?’ “

Initially shrugging it off, Kunath called Barran, professor of mass spectrometry at the University of Manchester, the next day and they talked it over. Was the woman referring to the fact that Parkinson’s patients often lose their sense of smell? Or making a rude comment about a patient’s personal hygiene? It wasn’t until another friend — also with a great sense of smell — heard the story and encouraged them to seek out the woman.

They tracked her down. She was Joy Milne, a retired nurse living in Perth, a town near Edinburgh. Decades earlier, Milne had noticed a sudden onset of a strange odor in her now-late husband. He was diagnosed with Parkinson’s disease many years later.

Milne is what’s known as a “super smeller,” a person with exceptional sense of smell. And they’re more common than you might think. Barran explains that many of them are professionals, called “noses,” working in the perfume or food and drink industries. As it turned out, to a super smeller like Milne, Parkinson’s disease has a distinct odor. More importantly, the odor is present long before physical symptoms appear.

The T-Shirt Test

The research team first had to confirm Milne’s abilities. So they conducted what they call the “the t-shirt test.” They recruited a handful of Parkinson’s patients and a control group (people without Parkinson’s) to sleep in identical t-shirts. Then, without telling her who was who, they presented them one at a time to Milne.

Not only did she correctly identify which t-shirts belonged to Parkinson’s patients, she could rank them based on the strength of the odor — even matching t-shirts that had been worn by the same person.

joy milne

Joy Milne (left) and researcher Perdita Barran. (Credit: The University of Manchester)

Milne had only one false positive: She flagged one shirt from the control group as having Parkinson’s. But that wasn’t the last they’d hear from that control group shirt-wearer, though. “They came back and said they indeed had just been diagnosed with Parkinson’s,” says Barran. “And that was a really extraordinary thing.”

Fast forward through grant proposals and some very skeptical funding review panels, and the team of researchers including Barran, Kunath and Milne embarked on more rigorous scientific tests to try to identify the specific compounds causing the odor that Milne was picking up on.

The Smell of Parkinson’s

The researchers initially assumed the smell had something to do with a person’s sweat. “We were trying to think about how we might be able to extract molecules from sweat … we had students running up and down hills with gauze under their armpits,” explains Barran.

But after initial trials with Milne and isolated sweat failed, they figured out that the scent was coming from the greasy sebum. Locating the origin of the scent allowed them to collect far more samples.

In the end, they were able to separate and identify the compounds found in sebum using what’s called gas chromatography mass spectrometry (GC-MS). They used Milne’s abilities to confirm the right combination of chemicals which, on a background of sebum-smell, make up “the smell of Parkinson’s.”

A New Way To Diagnose Parkinson’s?

The team is now working on training dogs to home in on the scents, as well as developing machinated diagnostic tests that could identify the presence of the tell-tale compounds, called biomarkers.

Milne isn’t the only one who can detect the smell — Barran says that many clinicians, even a hairdresser, have reached out to her to say they smell it too. Though Barran is a “non-smeller” — a head injury left her own sniffer out of whack — she says people always describe the smell in a similar way: Musky, reminiscent of how a beaver smells, yet unlike anything else.

Whether a new diagnostic test from the biomarkers comes from canines, super-smelling nurses or laboratory machines, the scientists’ goal is the same: Diagnose Parkinson’s earlier — possibly years earlier than current methods.

There’s not currently much — or any — early treatment for Parkinson’s but, Barran points out, there was never a way to catch it early enough to develop early treatments. This might soon change, though, all thanks to a retiree with an exceptional nose.

CBD Is In Jelly Beans, Pet Food and Shampoo. But Many Benefits Are Untested

By Troy Farah | March 18, 2019 4:58 pm
CBD oil

(Credit: ElRoi/Shutterstock)

CBD, or cannabidiol, has exploded onto the market in recent years. Sometime in the past decade, this purportedly medicinal marijuana extract went from being an obscure stoner oil to the wellness product du jour, flooding from holistic markets to the mainstream. Analysts at the investment bank Cowen Inc. predict the industry will balloon to $16 billion by 2025. In comparison, CBD sales totaled less than $1 billion last year, though that’s no small feat for a field that didn’t exist a few years ago.

CBD is purported to help with everything from depression to chronic pain and some animal studies suggest it may even help fight cancer, according to the National Cancer Institute. The most compelling evidence for its efficacy at the moment comes from studies of epilepsy patients who have seen their seizures reduced with the help of CBD. Read More

What Are Tholins? The Mysterious Substance That Turned Ultima Thule Red

By Korey Haynes | March 18, 2019 3:30 pm
Ultima Thule is likely covered in a red glaze of tholin. (Photo Credit: NASA)

Ultima Thule is likely covered in a red glaze of tholins, as depicted in this artist’s illustration. (Credit: NASA)

On New Year’s Day, NASA’s New Horizons probe streaked by a tiny world dubbed MU69, or Ultima Thule, the farthest object humankind has studied up close. With most of the data still on the spacecraft waiting to be transmitted, scientists are still getting to know this distant body. We know that it’s composed of two chunks of rock loosely stuck together. We know that it doesn’t have moons or rings that New Horizons might have careened into on its close pass. And we know Ultima Thule is red.

Carly Howett, a member of the New Horizons team, said that if you were standing on New Horizons as it sped past, Ultima Thule would appear red to the human eye and very dark. But with the aid of enhanced imagery, it’s also clear that some patches are redder than others, like the rim of the large crater known as Maryland.

That redness is likely caused by a mysterious class of compounds called tholins, the New Horizons team said Monday during a mission update at the 50th Lunar and Planetary Science Conference in Houston.

So what are tholins?

Broadly speaking, tholins are complex carbon chains made when ultraviolet light strikes carbon-rich molecules like methane or ethane. The result is a reddish, tarry substance. That may not sound exciting, but it was astronomer and science communication all-star Carl Sagan who named the material after creating it in his lab (along with fellow researcher Bishun Khare). They were performing variations on the famous Miller-Urey experiment, trying to recreate the chemical conditions on early Earth to see how life might have started.

The idea is that nature can, in the total absence of biology, produce more and more complicated carbon chains, until the leap to a biological protein, and presumably, life, is in fact just a single step. Tholins are complex, organic (meaning it contains carbon) molecules that could be a key step in this process. So scientists are very interested in where it’s occurring in the universe.

Ultima Thule looks red to the human eye

NASA scientists say that if you were on board the New Horizons spacecraft during its New Year’s flyby of Ultima Thule, the world would look visibly red to the human eye. That’s likely caused by compounds called tholins. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

In the Lab and in the Wild

Early Earth was likely a tholins-rich place. But in our current, oxygen-rich world, it exists only in labs (oxygen destroys tholins). Farther afield, researchers have found similar materials on Saturn’s moon Titan and Neptune’s moon Triton, as well as on lots of smaller icy bodies. But here is where the disagreement starts — it’s difficult to be sure how close the substances scientists create in labs are to the ones observed in space. They appear to be similar, but since we haven’t yet been able to bring back a sample from the outer solar system, appearances are all we have at the moment.

A reddish tint in certain environments is a pretty good hint that scientists might be looking at compounds that are at least similar to tholins, but there is far more than just one kind of potential tholin out there. Many different compounds can create various types of tholins, and picking out which might be present based just on their spectra, or the type of light they reflect, is nigh impossible. Mixed together and seen from afar, it’s not so easy to figure out one complex carbon chain from another.

Some researchers, such as planetary scientist Sarah Hörst of Johns Hopkins University, don’t like calling the outer-space versions tholins at all, since it’s hard to be sure what we’re looking at from so far away truly matches the substances created here on Earth. They are analogs, to be sure — but perhaps not the exact same thing.

Space Missions on the Tholin Hunt

close-up of a white surface spotted with red

New Horizons showed Pluto liberally swirled with red, tholin-like material. (Photo Credit: NASA/JHUAPL/SwRI)

But that’s all the more reason to study them as up-close as we can. The last decade has been filled with missions getting better looks at these far-off maybe-tholins. When the Cassini mission dropped the Huygens probe onto Titan, it revealed an entire world full of carbon-rich materials: on the ground, in the moon’s seas and lakes, and scattered throughout the atmosphere.

In 2015, the New Horizons probe flew by Pluto, painting a breathtakingly detailed view of the former planet — which was distinctly red in places, as is its sidekick moon Charon. Tholins (or something tholins-like) are the most likely culprit.

And now, as the new year dawned, New Horizons got an in-person glimpse at out an even more distant object, Ultima Thule, which is “very red,” according to New Horizons scientist Carly Howett. This puts it on par with other objects near it in the Kuiper Belt. “It’s a lot more red than things like comets,” Howett added.

Comets, in contrast to other Kuiper Belt objects, occasionally plunge into the inner solar system where they heat up and undergo chemical changes that never occur in the cold Kuiper Belt. This means that looking at Ultima Thule is a clean picture of primordial material from early in the solar system’s history.

The beautiful thing about tholins is that while they’re precious as a clue to our history as living organisms, they’re also pretty common. Carbon compounds like methane exist all over in the universe. Stars emit ultraviolet radiation every second, bathing the cosmos in it. The ingredients are easy to find. So if tholins are key to sparking life, we can look around and feel reassured that the makings for them are everywhere we look.

CATEGORIZED UNDER: Space & Physics, Top Posts

Humans Can Sense Earth’s Magnetic Field, Brain Imaging Study Says

compass brain

Do you have a magnetic compass in your head? (Credit: Triff/Shutterstock)

Do human beings have a magnetic sense? Biologists know other animals do. They think it helps creatures including bees, turtles and birds navigate through the world.

Scientists have tried to investigate whether humans belong on the list of magnetically sensitive organisms. For decades, there’s been a back-and-forth between positive reports and failures to demonstrate the trait in people, with seemingly endless controversy.

The mixed results in people may be due to the fact that virtually all past studies relied on behavioral decisions from the participants. If human beings do possess a magnetic sense, daily experience suggests that it would be very weak or deeply subconscious. Such faint impressions could easily be misinterpreted – or just plain missed – when trying to make decisions.

So our research group – including a geophysical biologist, a cognitive neuroscientist and a neuroengineer – took another approach. What we found arguably provides the first concrete neuroscientific evidence that humans do have a geomagnetic sense.

How Does A Biological Geomagnetic Sense Work?

The Earth is surrounded by a magnetic field, generated by the movement of the planet’s liquid core. It’s why a magnetic compass points north. At Earth’s surface, this magnetic field is fairly weak, about 100 times weaker than that of a refrigerator magnet.

earth magnetic field

Life on Earth is exposed to the planet’s ever-present geomagnetic field that varies in intensity and direction across the planetary surface. (Credit: Nasky/Shutterstock)

Over the past 50 years or so, scientists have shown that hundreds of organisms in nearly all branches of the bacterial, protist and animal kingdoms have the ability to detect and respond to this geomagnetic field. In some animals – such as honey bees – the geomagnetic behavioral responses are as strong as the responses to light, odor or touch. Biologists have identified strong responses in vertebrates ranging from fish, amphibians, reptiles, numerous birds and a diverse variety of mammals including whales, rodents, bats, cows and dogs – the last of which can be trained to find a hidden bar magnet. In all of these cases, the animals are using the geomagnetic field as components of their homing and navigation abilities, along with other cues like sight, smell and hearing.

Skeptics dismissed early reports of these responses, largely because there didn’t seem to be a biophysical mechanism that could translate the Earth’s weak geomagnetic field into strong neural signals. This view was dramatically changed by the discovery that living cells have the ability to build nanocrystals of the ferromagnetic mineral magnetite – basically, tiny iron magnets. Biogenic crystals of magnetite were first seen in the teeth of one group of mollusks, later in bacteria, and then in a variety of other organisms ranging from protists and animals such as insects, fish and mammals, including within tissues of the human brain.

Nevertheless, scientists haven’t considered humans to be magnetically sensitive organisms.


Chains of magnetosomes from a sockeye salmon. (Credit: Mann, Sparks, Walker & Kirschvink, 1988, CC BY-ND)

Manipulating the Magnetic Field

human magnetoreception

Schematic drawing of the human magnetoreception test chamber at Caltech. (Credit: Modified from ‘Center of attraction’ by C. Bickel (Hand, 2016))

In our new study, we asked 34 participants simply to sit in our testing chamber while we directly recorded electrical activity in their brains with electroencephalography (EEG). Our modified Faraday cage included a set of 3-axis coils that let us create controlled magnetic fields of high uniformity via electric current we ran through its wires. Since we live in mid-latitudes of the Northern Hemisphere, the environmental magnetic field in our lab dips downwards to the north at about 60 degrees from horizontal.

In normal life, when someone rotates their head – say, nodding up and down or turning the head from left to right – the direction of the geomagnetic field (which remains constant in space) will shift relative to their skull. This is no surprise to the subject’s brain, as it directed the muscles to move the head in the appropriate fashion in the first place.

rotate magnetic field

Study participants sat in the experimental chamber facing north, while the downwards-pointing field rotated clockwise (blue arrow) from northwest to northeast or counterclockwise (red arrow) from northeast to northwest. (Credit: Magnetic Field Laboratory, Caltech, CC BY-ND)

In our experimental chamber, we can move the magnetic field silently relative to the brain, but without the brain having initiated any signal to move the head. This is comparable to situations when your head or trunk is passively rotated by somebody else, or when you’re a passenger in a vehicle which rotates. In those cases, though, your body will still register vestibular signals about its position in space, along with the magnetic field changes – in contrast, our experimental stimulation was only a magnetic field shift. When we shifted the magnetic field in the chamber, our participants did not experience any obvious feelings.

The EEG data, on the other hand, revealed that certain magnetic field rotations could trigger strong and reproducible brain responses. One EEG pattern known from existing research, called alpha-ERD (event-related desynchronization), typically shows up when a person suddenly detects and processes a sensory stimulus. The brains were “concerned” with the unexpected change in the magnetic field direction, and this triggered the alpha-wave reduction. That we saw such alpha-ERD patterns in response to simple magnetic rotations is powerful evidence for human magnetoreception.


This video shows the dramatic, widespread drop in alpha wave amplitude (deep blue color on leftmost head) following counterclockwise rotations. No drop is observed after clockwise rotation or in the fixed condition. (Credit: Connie Wang, Caltech)

Our participants’ brains only responded when the vertical component of the field was pointing downwards at about 60 degrees (while horizontally rotating), as it does naturally here in Pasadena, California. They did not respond to unnatural directions of the magnetic field – such as when it pointed upwards. We suggest the response is tuned to natural stimuli, reflecting a biological mechanism that has been shaped by natural selection.

Other researchers have shown that animals’ brains filter magnetic signals, only responding to those that are environmentally relevant. It makes sense to reject any magnetic signal that is too far away from the natural values because it most likely is from a magnetic anomaly – a lighting strike, or lodestone deposit in the ground, for example. One early report on birds showed that robins stop using the geomagnetic field if the strength is more than about 25 percent different from what they were used to. It’s possible this tendency might be why previous researchers had trouble identifying this magnetic sense – if they cranked up the strength of the magnetic field to “help” subjects detect it, they might have instead ensured that subjects’ brains ignored it.

Moreover, our series of experiments show that the receptor mechanism – the biological magnetometer in human beings – is not electrical induction, and can tell north from south. This latter feature rules out completely the so-called “quantum compass” or “cryptochrome” mechanism which is popular these days in the animal literature on magnetoreception. Our results are consistent only with functional magnetoreceptor cells based on the biological magnetite hypothesis. Note that a magnetite-based system can also explain all of the behavioral effects in birds that promoted the rise of the quantum compass hypothesis.

Brains Register Magnetic Shifts, Subconsciously

Our participants were all unaware of the magnetic field shifts and their brain responses. They felt that nothing had happened during the whole experiment – they’d just sat alone in dark silence for an hour. Underneath, though, their brains revealed a wide range of differences. Some brains showed almost no reaction, while other brains had alpha waves that shrank to half their normal size after a magnetic field shift.

It remains to be seen what these hidden reactions might mean for human behavioral capabilities. Do the weak and strong brain responses reflect some kind of individual differences in navigational ability? Can those with weaker brain responses benefit from some kind of training? Can those with strong brain responses be trained to actually feel the magnetic field?

A human response to Earth-strength magnetic fields might seem surprising. But given the evidence for magnetic sensation in our animal ancestors, it might be more surprising if humans had completely lost every last piece of the system. Thus far, we’ve found evidence that people have working magnetic sensors sending signals to the brain – a previously unknown sensory ability in the subconscious human mind. The full extent of our magnetic inheritance remains to be discovered.The Conversation


Shinsuke Shimojo, Gertrude Baltimore Professor of Experimental Psychology, California Institute of Technology; Daw-An Wu, , California Institute of Technology, and Joseph Kirschvink, Nico and Marilyn Van Wingen Professor of Geobiology, California Institute of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

CATEGORIZED UNDER: Living World, Mind & Brain, Top Posts
MORE ABOUT: animals, senses

Meet Chesley Bonestell, The Most Important Space Artist You’ve Probably Never Heard Of

By Richard Tresch Fienberg | March 15, 2019 5:00 pm
Saturn, as seen from its moon Titan, which we now know is covered in an atmosphere so thick you can't see through it. (Chesley Bonestell)

This 1944 view of Saturn as seen from its largest moon, Titan, is one of Chesley Bonestell’s most famous paintings. The artist used his knowledge of astronomy to depict the ringed planet at the correct angular size for Titan’s orbital distance. (Credit: Courtesy Bonestell LLC.)

Over the last half century, spacecraft have visited every planet and their major moons, as well as two dwarf planets and more than a dozen asteroids and comets. Thanks to high-res images, we know these worlds intimately and can appreciate what makes each of them unique. These days, fewer than 3 in 10 Americans are old enough to recall a time when our neighboring worlds were indistinct dots in even the most powerful telescopes.

And yet, even before there were spacecraft to show us, in the 1940s and ‘50s, readers of magazines such as Collier’s, LIFE, and Sky & Telescope had a pretty good idea what kinds of scenery we might find on the moon, Mars, Pluto, and the moons of the outer planets. All these worlds came to life in paintings by a single visionary artist: Chesley Bonestell (pronounced BONN-uh-stell). He’s the subject of a new feature-length documentary, “Chesley Bonestell: A Brush with the Future.” If you’ve never heard of Bonestell, you’ll come away from the film wondering why not. And if, like me, you knew something of Bonestell’s life and work, you’ll be astonished to discover how much more you didn’t know. Read More

CATEGORIZED UNDER: Space & Physics, Top Posts

When Did Humans Start to Get Old?

By Bridget Alex | March 15, 2019 4:48 pm
old couple

(Credit: Monkey Business Images.Shutterstock)

Age 116, Kane Tanaka of Japan was recently crowned the oldest person on Earth. She’s six years shy of the longest human life on record: 122 years and 164 days reached by a French woman, Jeanne Louise Calment, before her death in 1997.

While turning 100 can get you a shout out on the Today show, there’s nothing newsworthy about surviving into your 70s. That’s just expected based on life expectancy. In the United States, on average, newborn males live to 76 years and females to 81, according to the latest statistics from the National Center for Health Statistics. For most of the past century life expectancy has been increasing, thanks to improved healthcare, hygiene and nutrition.

But what about before the advent of modernity, say, 30,000 years before? It’s a question many scientists have tried to answer — whether ancient Homo sapiens perished in their 30s or lived on into the autumn of their lives.

Just how old is old age?

There’s little doubt among anthropologists that the actual biological capacity to reach old age goes way back: To the dawn of our species some 300,000 years ago, or even earlier, to the origins of the genus Homo roughly 2 million years ago. We’ve had the ability to survive into our 70s and 80s for a long time.

What’s unclear is how often this potential was realized. Researchers still aren’t sure how common it would have been to see octogenarians in Stone Age societies.

Hunter-Gatherer Grandparents

One way anthropologists have tried to answer the question is by looking at mortality data from present-day people with more traditional lifestyles. In particular they’ve studied foragers and subsistence farmers with minimal exposure to modern medicine or technology. The idea is that such groups have the habits and hazards most similar to our ancient ancestors.

For traditional societies life expectancy from birth is 3-4 decades, compared to 7-8 decades for contemporary, industrialized societies. But, this may give the false impression that hunter-gatherers are largely keeling over in their 30s. Not so.

life expectancy

This chart shows the number of years someone can expect to live at birth and at age 65. Notice the increase in life expectancy for those who make it to 65. (Credit: NCHS)

The value includes deaths during infancy and childhood, the riskiest phase of life for most of human history, and still today in many parts of the world. A 2013 review found that across 18 recent hunter-gatherer groups, one quarter of children die before their first birthdays and nearly half (48 percent) do before age 15. The values were nearly identical to those from 43 surveyed historical civilizations, including Classical Rome, medieval Japan and Renaissance Europe. This means, without modern medicine and technology, babies have only had a 50-50 shot of surviving to age 15, in all the times and places from which we have historical or ethnographic data. For comparison, in modern Western countries today, death rates are around 1 percent for children (age 0-15) and 0.1 percent for infants.

So, the abundance of early demises brings down the average lifespan from birth in traditional societies.

Other longevity measures provide a better sense of a group’s demographic makeup. Take instead life expectancy only for individuals who make it to their 15th birthday. Of this subset, nearly two thirds eventually reach their late 60s or 70s, according to a 2007 analysis of 12 traditional societies.

Considering those age 15 and above, the study also calculated the age at which most people die, or the modal age at death (yes, the stat from “mean, median and mode” that you never thought you’d use in fourth grade). This value for foragers and traditional farmers was 72, equivalent to the age most Swedish people died in the mid-1700s. Modal age of death for the United States in 2002 was 85.

As the study authors put it, “The effective end of the human life course under traditional conditions seems to be just after age 70 years.” Anyone who makes it through childhood has a good shot of becoming an elder.

death ages

This graph compares when individuals from various societies are more likely to die. (Credit: Michael Gurven and Hillard Kaplan)

Boney Birth Certificates

Of course no one today is experiencing conditions identical to those of our Stone Age predecessors. Therefore, to understand the antiquity of old age, other anthropologists have directly studied human ancestors — or at least the bones and teeth they left behind.

Researchers will attempt to assign an age-at-death to the remains of ancient humans in order to estimate the prevalence of elders in a population. But there’s two major problems with this approach. First, the collection of skeletons needs to be representative of the full group. Not just a random bunch of people who died and were preserved for 20,000-plus years, but an authentic snapshot of demise rates across different ages. To address this issue, researchers use statistical methods to check if they have enough skeletal remains to make meaningful inferences.

The other problem is that it’s impossible to precisely determine the age of an adult skeleton. As children are growing, their bones fuse and teeth develop along a predictable calendar. The last definitive age indicator occurs in the late teens, when the third molars, or wisdom teeth, emerge. After that estimates are fuzzy, and based on the amount of wear and tear that accumulates on bones and teeth with each passing year. Of course, diet and activity levels influence this metric, so the method is hardly precise. It only places people within a decade or so of their actual age (It’s totally unrealistic when they age adult skeletons down to the year on CSI or Bones).

dental wear

A chart used to pair dental wear with rough age brackets. (Credit: Lovejoy (1985))

Given this limitation, anthropologists have simply identified all the skeletons with third molars and then divided them into categories of “young adult” (20-40 years) and “old adult” (over 40).

This approach was first applied to fossil teeth from 768 individuals including Paleolithic European Homo sapiens, Neanderthals and earlier species of human ancestors. Old adults were present across all time periods, but were by far most common among remains from European H. sapiens of the past 50,000 years, suggesting more than a 5-fold increase in elderly individuals. Modern humans, by this measure, had many more individuals that went on to reach old age than our evolutionary cousins.

A more recent study using this method, compared Stone Age Homo sapiens and Neanderthals to archaeological skeletons from the past 10,000 years as well as historical and ethnographic death data. The proportion of older adults from the Stone Age was slim compared to that from people of the past 10,000 years. Adult longevity, at least as measured over thousands of years, has actually gone up.

Other scientists disagree with the implications of these studies, though, arguing that the approach does not provide an honest picture of elders’ presence in the past.

Regardless, it’s clear from fossils and traditional societies today that even without modern medicine or technology humans can make it to their geriatric years. Old age is nothing new.

Top Scientists Call for Moratorium Blocking Gene-Edited Babies; Critics Want Action

By Anna Groves | March 13, 2019 2:00 pm
Chinese scientist He Jiankui presents his research in Hong Kong in November 2018. (Credit: Ernie Mastroianni/Discover)

Chinese scientist He Jiankui presents his research in Hong Kong in November 2018. (Credit: Ernie Mastroianni/Discover)

More than a dozen top scientists from seven countries are calling for world governments to adopt a moratorium on what scientists call heritable genome editing. They’re on a mission to make sure the world doesn’t see any more gene-edited babies — not till we’re good and ready — and they’ve got a plan to stop it.

The group penned a commentary published Wednesday in the journal Nature. The effort was led by Eric Lander, director of the Broad Institute and a professor at both MIT and Harvard University. Lander says the call is in reaction to the recent surprise announcement that a Chinese researcher had experimented with gene editing on actual humans. International scientists were shocked when He Jiankui revealed he’d edited the genes of twin girls who born in China last November.

Heritable genome editing has only recently been possible. It’s when scientists alter the DNA of embryos — human cells that, if implanted in a uterus, will grow into a baby — in a way that permanently alters the DNA of every cell in the body. Changes here would also alter the DNA of generations to come.
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CATEGORIZED UNDER: Health & Medicine, Top Posts

Many Families With High Breast Cancer Risk Await a Genetic Explanation

By Ashleen Knutsen | March 11, 2019 5:30 pm
breast cancer risk

The average woman’s lifetime risk of breast cancer is 12 percent. Some families with higher risks do not yet have an identified genetic cause.(Credit: Sebastian Kaulitzki/shutterstock)

For decades, Piri Welcsh has had professional and personal stakes in understanding the genetics of breast cancer.

In the 1990s, the molecular geneticist participated in an international race to clone BRCA1, the first gene linked to breast cancer risk, and she works to this day in the lab of pioneering breast cancer geneticist Mary-Claire King at the University of Washington.

And then there’s Welcsh’s own family. Her grandmother died of breast cancer, her mother is a breast cancer survivor, and her aunt was just diagnosed with breast cancer.

Since the days of the BRCA1 discovery, researchers have identified more than 100 genes that, in certain forms, raise breast cancer risk. And yet that still leaves many people with elevated familial risk seeking answers. “Some families, like mine, are unsolved,” says Welcsh, who is vice president of education for the support group FORCE: Facing Our Risk of Cancer Empowered. “They seem to have something genetic being passed through generations, yet no mutation identified.”

Researchers hope to offer explanations to many women like Welcsh by broadening their knowledge of the genes and gene variants involved in breast cancer risk through a focus on tiny DNA differences between one person’s genome and the next — variants known as SNPs, or single nucleotide polymorphisms. By so doing, they aim to come to a better understanding of the causes of breast cancer and develop more comprehensive screening panels — and, down the road, perhaps new and more bespoke treatments.

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CATEGORIZED UNDER: Health & Medicine, Top Posts
MORE ABOUT: cancer, personal health

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