By Apoorva Mandavilli A small biotech company that trumpeted an exciting new treatment for Alzheimer’s disease is now under fire for irregularities in its research results, after several studies related to its work were retracted or questioned by scientific journals. The company, Cassava Sciences, based in Austin, Texas, announced last summer that its drug, simufilam, improved cognition in Alzheimer’s patients in a small clinical trial, describing it as the first such advance in treatment of the disease. Cassava later initiated a larger trial. The drug’s potential garnered enormous attention from investors. Alzheimer’s disease affects roughly six million Americans, a number that is expected to double by 2050, and an effective treatment would be lucrative. Cassava’s stock soared, by more than 1,500 percent at one point. The company was worth nearly $5 billion last summer. But many scientists have been deeply skeptical of the company’s claims, asserting that Cassava’s studies were flawed, its methods opaque and its results improbable. Families of some trial participants have said they see improvements. But critics noted that the trial reporting better cognition due to simufilam lacked a placebo group, and asserted that the Alzheimer’s patients were not followed long enough to confirm that any improvements in cognition were genuine. Some experts went further, accusing the company of manipulating its scientific results. In response to the allegations, in December The Journal of Neuroscience published “expressions of concern” regarding two brain studies authored by the company’s chief collaborator, Hoau-Yan Wang, a professor at the City University of New York. One was co-written by Lindsay H. Burns, chief scientist at Cassava. The journal editors also noted errors in the images accompanying the latter study. (An “expression of concern” indicates that the editors have reason to question the integrity and accuracy of a paper.) © 2022 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28290 - Posted: 04.20.2022

Hannah Devlin Science correspondent The largest genetic study of Alzheimer’s to date has provided compelling evidence linking the disease to disruption in the brain’s immune system. The study, using the genomes of 100,000 people with Alzheimer’s and 600,000 healthy people, identified 75 genes linked to an increased risk of the disease, including 42 that had not previously been implicated. The findings suggest degeneration in the brains of dementia patients could be spurred on by “over-aggressive” activity in the brain’s immune cells, called microglia. Prof Julie Williams, the director of the UK Dementia Research Institute at Cardiff University and a co-author of the study, said the findings could help reignite efforts to find an effective treatment. “This is an enormous clue to what’s going wrong,” she said. “Eight or nine years ago we weren’t working on the immune system. The genetics has refocused us.” The study, the largest of its kind to date, also allowed scientists to devise a genetic risk score that could predict which patients with cognitive impairment would, within three years of first showing symptoms, go on to develop Alzheimer’s. The score is not intended for clinical use at the moment, but could be used when recruiting people for clinical trials of drugs aimed at treating the disease in the earliest stages. Alzheimer’s disease is the most common cause of dementia, which affects more than 850,000 people in the UK. Despite the huge burden of the disease, there have been no new drugs for it in the past two decades, with the exception of Aducanumab, controversially licensed in the US but unavailable in Europe and the UK. Previous research has shown that while lifestyle factors such as smoking, exercise and diet influence Alzheimer’s risk, 60%-80% of the disease risk is based on genetics. However, Williams said, drug development was heavily influenced by the study of families with rare genetic mutations causing early onset Alzheimer’s. © 2022 Guardian News & Media Limited

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28267 - Posted: 04.06.2022

By Ariana Eunjung Cha People with “chemo brain” and covid brain fog could not seem more different: Those with “chemo brain” have a life-threatening disease for which they’ve taken toxic drugs or radiation. Many of those with covid brain fog, in contrast, describe themselves as previously healthy people who have had a relatively mild infection that felt like a cold. So when Stanford University neuroscientist Michelle Monje began studies on long covid, she was fascinated to find similar changes among patients in both groups, in specialized brain cells that serve as the organ’s surveillance and defense system. “It was really quite striking,” Monje said. In cancer patients undergoing treatment, a malfunction in those same cells, known as microglia, are believed to be a cause of the fuzzy thinking that many describe. Scientists have also theorized that in Alzheimer’s disease, these cells may be impeded, making it difficult for them to counteract the cellular wear and tear of aging. Monje’s project is part of a crucial and growing body of research that suggests similarities in the mechanisms of post-covid cognitive changes and other long-studied brain conditions, including “chemo brain,” Alzheimer’s and other post-viral syndromes following infections with influenza, Epstein-Barr, HIV or Ebola. “There is humongous overlap” between long covid and these other conditions, said Avindra Nath, intramural clinical director of the neurological disorders and stroke unit of the National Institutes of Health. Pre-covid, much of the medical research into brains (as well as other organs) was siloed by disease. But during the pandemic, as diverse scientists banded together to understand a complex, multi-organ disease, commonalities among the conditions began coming to light. © 1996-2022 The Washington Post

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 13: Memory and Learning
Link ID: 28259 - Posted: 03.30.2022

Yue Leng Doctors often recommend “power naps” as a way to compensate for a poor night’s sleep and help keep alert until bedtime. But for older adults, extensive power naps could be an early sign of dementia. Research on how napping affects cognition in adults has had mixed results. Some studies on younger adults suggest that napping is beneficial to cognition, while others on older adults suggest it may be linked to cognitive impairment. However, many studies are based on just a single self-reported nap assessment. This methodology may not be accurate for people with cognitive impairment who may not be able to reliably report when or how long they napped. As an epidemiologist who studies sleep and neurodegeneration in older adults, I wanted to find out if changes in napping habits foreshadow other signs of cognitive decline. A study my colleagues and I recently published found that while napping does increase with age, excessive napping may foreshadow cognitive decline. Sleep may play a significant role in Alzheimer’s development. The link between daytime napping and dementia Sleep disturbance and daytime napping are known symptoms of mild to moderate Alzheimer’s disease and other forms of dementia in older adults. They often become more extreme as the disease progresses: Patients are increasingly less likely to fall asleep and more likely to wake up during the night and feel sleepy during the day. © 2010–2022, The Conversation US, Inc.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 10: Biological Rhythms and Sleep
Link ID: 28256 - Posted: 03.30.2022

Hannah Devlin Science corespondent Taking long naps could be a precursor of Alzheimer’s disease, according to a study that tracked the daytime sleeping habits of elderly people. The findings could help resolve the conflicting results of the effects of napping on cognition in older adults, with some previous studies highlighting the benefits of a siesta on mood, alertness and performance on mental tasks. The latest study suggests that an increase over time in naps was linked to a higher chance of developing mild cognitive impairment or Alzheimer’s. The scientists think it is more likely that excessive napping could be an early warning sign, rather than it causing mental decline. “It might be a signal of accelerated ageing,” said Dr Yue Leng, an assistant professor of psychiatry at the University of California San Francisco. “The main takeaway is if you didn’t used to take naps and you notice you’re starting to get more sleepy in the day, it might be a signal of declining cognitive health.” The scientists tracked more than 1,000 people, with an average age of 81, over several years. Each year, the participants wore a watch-like device to track mobility for up to 14 days. Each prolonged period of non-activity from 9am to 7pm was interpreted as a nap. The participants also underwent tests to evaluate cognition each year. At the start of the study 76% of participants had no cognitive impairment, 20% had mild cognitive impairment and 4% had Alzheimer’s disease. For participants who did not develop cognitive impairment, daily daytime napping increased by an average 11 minutes a year. The rate of increase doubled after a diagnosis of mild cognitive impairment to a total of 24 minutes and nearly tripled to a total of 68 minutes after a diagnosis of Alzheimer’s disease, according to the research published in the journal Alzheimer’s and dementia. © 2022 Guardian News & Media Limited

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 10: Biological Rhythms and Sleep
Link ID: 28244 - Posted: 03.19.2022

Jon Hamilton About 1 in 7 people age 60 or older have a brain condition that may be an early sign of Alzheimer's disease. The condition, called mild cognitive impairment, occupies a gray zone between normal aging of the brain and dementia. And most people know almost nothing about it. A national survey found that 82% of Americans are unfamiliar with the condition or know very little about it. More than half thought the symptoms sounded like "normal aging," according to the survey, which was part of a special report released this week by the Alzheimer's Association. "Mild cognitive impairment is often confused with normal aging because it is very subtle," says Maria Carrillo, chief science officer of the Alzheimer's Association. Symptoms include "forgetting people's names, forgetting perhaps that you've said something already, forgetting a story, forgetting words," she says. The condition, which affects about 10 million people in the U.S., is defined as changes in memory and thinking that are noticeable to the affected person and those around them but not serious enough to interfere with the individual's everyday activities. That makes it tricky to diagnose, says Dr. Pierre Tariot, director of the Banner Alzheimer's Institute in Phoenix. So after talking to a patient, Tariot often asks if he can speak with the person's spouse or a close family member. A patient's wife, for example, might notice that her husband is still managing to keep his appointments, Tariot says, but then she adds: "But a year ago, he had it all locked and loaded in his brain. And now, unless he writes it down 12 times and then asks me to double-check, he's not going to get there." © 2022 npr

Related chapters from BN: Chapter 17: Learning and Memory; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 13: Memory and Learning
Link ID: 28243 - Posted: 03.19.2022

By Linda Searing The more fit you are, the less likely you may be to develop Alzheimer’s disease — with those who are the most fit having a 33 percent lower risk for this dementia than the least fit, according to a report to be presented to the American Academy of Neurology at its annual meeting next month. FAQ: What to know about the omicron variant of the coronavirus D.C.-based researchers, from the Washington VA Medical Center and George Washington University, tested and tracked 649,605 veterans (average age 61) for nearly a decade. Based on their cardiorespiratory fitness, participants were divided into five categories, from lowest to highest fitness level. 10-minute exercising may slow progression to dementia for those with mild cognitive impairment The researchers found that, as fitness improved, people’s chances of developing the ailment decreased. Compared with the least-fit group, those slightly more fit had a 13 percent lower risk for Alzheimer’s; the middle group was 20 percent less likely to develop the disease; the next higher group was 26 percent less likely; with the odds reaching a 33 percent lower risk for those in the most-fit group. Alzheimer’s is the most common type of dementia. It is a progressive brain disorder that, over time, destroys memory and thinking skills and interferes with the ability to carry out daily tasks. About 6 million Americans 65 and older have Alzheimer’s. There are no proven ways to cure the disease. © 1996-2022 The Washington Post

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 5: The Sensorimotor System
Link ID: 28239 - Posted: 03.16.2022

Alison Abbott Every two weeks, a nurse visits 43-year-old Marty Reiswig in Denver, Colorado, and injects him with an experimental drug called gantenerumab. Every month, Reiswig drives into town for a brain scan to make sure the drug has not caused any bleeds. And every year he flies to St Louis, Missouri, for four days of brain scans, spinal taps, blood analyses and exhaustive tests of his memory and reasoning capacity. Reiswig is fit and healthy and runs two local businesses. He goes through all of this because he has a rare genetic mutation that almost guarantees he will develop early-onset Alzheimer’s disease. He hopes that the international clinical trial he has been part of for nine years might prevent, or at least delay, the onset of symptoms that will otherwise arise in just a few years’ time. “I always do my best to give the researchers as much as I can — even if it turns out not to help me, it might help my children,” he says. The trial is one of several trying to understand whether treating the root cause of Alzheimer’s before symptoms start might be the best way to handle a disease that exacts such a large toll. The drugs under scrutiny are all antibodies that have been developed to target and clear amyloid-β proteins in the brain, which clog together into toxic masses called plaques (see ‘Antibodies against amyloid’). These drugs are of the same type as aducanumab, made by Biogen in Cambridge, Massachusetts, which was provisionally approved last year by the US Food and Drug Administration (FDA) for the treatment of mild Alzheimer’s, in large part owing to its ability to remove amyloid-β. And because such toxic proteins are a feature of several types of dementia, these antibody studies might also offer hints for how to treat the 55 million people around the world who have these conditions, says neurologist Paul Aisen at the University of Southern California in San Diego, who is a leader of the US Alzheimer’s Clinical Trials Consortium. Most dementias hit after 65 years of age; all have proved to be stubbornly incurable. Of more than 100 trials around the world, most are aiming to treat symptoms of the disease rather than its root cause. © 2022 Springer Nature Limited

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28236 - Posted: 03.11.2022

By Gina Kolata Dr. John Q. Trojanowski, a neuropathologist whose work was at the forefront of research on Alzheimer’s and other neurodegenerative diseases, died on Feb. 8 in a hospital in Philadelphia. He was 75. His wife and longtime collaborator, Virginia M.-Y. Lee, said the cause was complications of chronic spinal cord injuries. Dr. Trojanowski “was a giant in the field,” said Leslie Shaw, a professor with Dr. Trojanowski in the department of pathology and laboratory medicine at the University of Pennsylvania — adding that he meant that in two ways. At 6 feet 4 inches, Dr. Trojanowski towered over his colleagues. And, Dr. Shaw said, he was also a towering figure in his field, whose scientific contributions were “phenomenal” because they combined pathology and biochemistry to figure out what goes wrong, and why, when people get diseases as disparate as Alzheimer’s, Parkinson’s and A.L.S. The results can lead to improved diagnosis and potential treatments. Key to the work Dr. Trojanowski did with Dr. Lee was their establishment of a brain bank: stored brains from patients with diseases like Alzheimer’s and Parkinson’s, as well as from people without degenerative brain diseases. It allowed them to compare the brains of people with and without the conditions and ask what proteins were involved in the diseases and what brain regions were affected. Among their first quests was an attempt to solve the mystery of strange areas in the brains of people with Alzheimer’s. Known as tangles and first described by Alois Alzheimer himself at the turn of the 20th century, they look like twisted strands of spaghetti in dying nerve cells. In 1991, Dr. Trojanowski and Dr. Lee determined that the regions are made up of a malformed protein called tau, which causes the structure of nerve cells to collapse. At a time when most Alzheimer’s researchers and drug companies were focused on a different protein, amyloid, Dr. Trojanowski and Dr. Lee insisted that tau was equally important. They then discovered that it also played a central role in a rare group of degenerative dementias known as frontotemporal lobar degeneration. © 2022 The New York Times Company

Related chapters from BN: Chapter 11: Motor Control and Plasticity; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory and Learning
Link ID: 28225 - Posted: 03.02.2022

Ian Sample Science editor People who develop Alzheimer’s disease can experience sleep disturbances years before the condition takes hold, but whether one causes the other, or something more complex is afoot, has always proved hard for scientists to determine. Now, researchers in the US have shed light on the mystery, in work that raises hopes for new therapies, and how “good sleep hygiene” could help to tackle the disease and its symptoms. The findings show that humans’ 24-hour circadian clock controls the brain’s ability to mop up wayward proteins linked to Alzheimer’s disease. If the scientists are right, the work would explain, at least in part, how disruption to circadian rhythms and sleep disturbances might feed into the onset and progression of Alzheimer’s disease, and how preventing such disruption might stave off the condition. “Circadian disruption is correlated with Alzheimer’s diagnosis and it has been suggested that sleep disruptions could be an early warning sign of Alzheimer’s disease,” said Dr Jennifer Hurley, who led the research at Rensselaer Polytechnic Institute, in New York. Alzheimer’s takes hold when connections are lost between nerve cells in the brain. The disease is progressive and linked to abnormal plaques and tangles of proteins that steadily build up in the brain. The disease is the most common cause of dementia and affects more than half a million people in the UK, a figure that is set to rise. To keep the brain healthy, immune cells called microglia seek out and destroy troublesome proteins that threaten to accumulate in the brain. One type of protein targeted by the cells is called amyloid beta, a hallmark of Alzheimer’s. © 2022 Guardian News & Media Limited

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 10: Biological Rhythms and Sleep
Link ID: 28197 - Posted: 02.12.2022

By Elizabeth Landau My grandmother was in the advanced stages of Alzheimer’s disease when she died in 2007, not long after I graduated from journalism school. As a budding health reporter, I tried to learn everything I could about Alzheimer’s and wrote about new research on preventions and treatments that everyone wanted to believe had potential. It is demoralizing and infuriating to think about how, nearly 15 years later, no breakthrough cure or proven prevention strategy has panned out. But neurologist Sara Manning Peskin argues in “A Molecule Away from Madness: Tales of the Hijacked Brain” that we could be on the brink of a revolution in confronting diseases like this because scientists have a better handle on how molecules work in the brain. Molecular research has transformed our understanding and treatment of cancer in recent years, and now it is beginning to do the same for brain diseases. In fact, it has already been key to solving several mysteries of why seemingly healthy people appear to suddenly fall into a mental inferno. While the shadow of Alzheimer’s looms over the book, representing an intractable condition that Peskin routinely confronts in her clinical practice, “A Molecule Away from Madness” is a fascinating tour of different kinds of ways that the brain can lead to the breakdown of mental life. The book is organized according to how different molecules interact with our brains to wreak havoc — Peskin calls them “mutants, rebels, invaders, and evaders.” Some have helped scientists solve longstanding puzzles, while others, like the molecules associated with Alzheimer’s, continue to leave millions of people waiting for a cure.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 4: Development of the Brain
Link ID: 28196 - Posted: 02.12.2022

Bret Stetka It all started with genetic data. A gene here, a gene there. Eventually the story became clearer: If scientists are to one day find a cure for Alzheimer's disease, they should look to the immune system. Over the past couple decades, researchers have identified numerous genes involved in various immune system functions that may also contribute to Alzheimer's. Some of the prime suspects are genes that control humble little immune cells called microglia, now the focus of intense research in developing new Alzheimer's drugs. Microglia are amoeba-like cells that scour the brain for injuries and invaders. They help clear dead or impaired brain cells and literally gobble up invading microbes. Without them, we'd be in trouble. In a normal brain, a protein called beta-amyloid is cleared away through our lymphatic system by microglia as molecular junk. But sometimes it builds up. Certain gene mutations are one culprit in this toxic accumulation. Traumatic brain injury is another, and, perhaps, impaired microglial function. One thing everyone agrees on is that in people with Alzheimer's, too much amyloid accumulates between their brain cells and in the vessels that supply the brain with blood. Once amyloid begins to clog networks of neurons, it triggers the accumulation of another protein, called tau, inside of these brain cells. The presence of tau sends microglia and other immune mechanisms into overdrive, resulting in the inflammatory immune response that many experts believe ultimately saps brain vitality in Alzheimer's. To date, nearly a dozen genes involved in immune and microglial function have been tied to Alzheimer's. The first was CD33, identified in 2008. © 2022 npr

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 11: Emotions, Aggression, and Stress
Link ID: 28184 - Posted: 02.02.2022

By Jane E. Brody Many people aren’t overly concerned when an octogenarian occasionally forgets the best route to a favorite store, can’t remember a friend’s name or dents the car while trying to parallel park on a crowded city street. Even healthy brains work less efficiently with age, and memory, sensory perceptions and physical abilities become less reliable. But what if the person is not in their 80s but in their 30s, 40s or 50s and forgets the way home from their own street corner? That’s far more concerning. While most of the 5.3 million Americans who are living with Alzheimer’s disease or other forms of dementia are over 65, some 200,000 are younger than 65 and develop serious memory and thinking problems far earlier in life than expected. “Young-onset dementia is a particularly disheartening diagnosis because it affects individuals in the prime years,” Dr. David S. Knopman, a neurologist at the Mayo Clinic in Rochester, Minn., wrote in a July 2021 editorial in JAMA Neurology. Many of the afflicted are in their 40s and 50s, midcareer, hardly ready to retire and perhaps still raising a family. Dementia in a younger adult is especially traumatic and challenging for families to acknowledge, and many practicing physicians fail to recognize it or even suspect it may be an underlying cause of symptoms. “Complaints about brain fog in young patients are very common and are mostly benign,” Dr. Knopman told me. “It’s hard to know when they’re not attributable to stress, depression or anxiety or the result of normal aging. Even neurologists infrequently see patients with young-onset dementia.” Yet recent studies indicate that the problem is far more common than most doctors realize. Worldwide, as many as 3.9 million people younger than 65 may be affected, a Dutch analysis of 74 studies indicated. The study, published in JAMA Neurology in September, found that for every 100,000 people aged 30 to 64, 119 had early dementia. © 2022 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28161 - Posted: 01.19.2022

Mitch Leslie Medicine so far has nothing to offer that clearly prevents Alzheimer’s disease, although keeping your weight down, exercising regularly, and inheriting certain protective genes can lower your risk. Now, a study has identified another, unexpected source of protection: clonal hematopoiesis, a blood cell imbalance best known as a risk factor for cancer and heart disease. “Clonal hematopoiesis has been associated with so many bad outcomes that it is surprising that it is protective in this situation,” says cardiovascular biologist Kenneth Walsh of the University of Virginia, who wasn’t connected to the study, reported on 12 December at the American Society of Hematology meeting in Atlanta. But Walsh says the work is convincing and “will have to be reckoned with and explained.” He and other researchers caution that the discovery doesn’t offer any immediate opportunities for treating or preventing Alzheimer’s disease. Given the negative health effects of clonal hematopoiesis, inducing it in healthy people is a nonstarter. Still, the finding has a provocative implication: that cells from the bloodstream are restocking the brain’s immune cells, perhaps bolstering its ability to clear out toxic debris. Charles Darwin probably never imagined that natural selection unfolds in our bone marrow. But clonal hematopoiesis results from competition among the 50,000 to 200,000 stem cells that dwell there and divide to produce all our red and white blood cells. Over the years these stem cells accrue mutations, some of which result in a “fitter” cell whose progeny, known collectively as a clone, can soon outnumber their counterparts. In some people with clonal hematopoiesis, the offspring of a single mutated stem cell account for more than half of the blood cells in the body. © 2021 American Association for the Advancement of Science.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28114 - Posted: 12.15.2021

By Pam Belluck What if something in the blood of an athlete could boost the brainpower of someone who doesn’t or can’t exercise? Could a protein that gets amplified when people exercise help stave off symptoms of Alzheimer’s and other memory disorders? That’s the tantalizing prospect raised by a new study in which researchers injected sedentary mice with blood from mice that ran for miles on exercise wheels, and found that the sedentary mice then did better on tests of learning and memory. The study, published Wednesday in the journal Nature, also found that the type of brain inflammation involved in Alzheimer’s and other neurological disorders was reduced in sedentary mice after they received their athletic counterparts’ blood. “We’re seeing an increasing number of studies where proteins from outside the brain that are made when you exercise get into the brain and are helpful for improving brain health, or even improving cognition and disease,” said Rudolph Tanzi, a professor of neurology at Massachusetts General Hospital and Harvard Medical School. He led a 2018 study that found that exercise helped the brains of mice engineered to have a version of Alzheimer’s. The most promising outcome would be if exercise-generated proteins can become the basis for treatments, experts said. The study, led by researchers at Stanford School of Medicine, found that one protein — clusterin, produced in the liver and in heart muscle cells — seemed to account for most of the anti-inflammatory effects. But several experts noted that recent studies have found benefits from other proteins. They also said more needs to be learned about clusterin, which plays a role in many diseases, including cancer, and may have negative effects in early stages of Alzheimer’s before brain inflammation becomes dominant. © 2021 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 8: Hormones and Sex
Link ID: 28108 - Posted: 12.11.2021

By Gretchen Reynolds Staying physically active as we age substantially drops our risk of developing dementia during our lifetimes, and it doesn’t require prolonged exercise. Walking or moving about, rather than sitting, may be all it takes to help bolster the brain, and a new study of octogenarians from Chicago may help to explain why. The study, which tracked how often older people moved or sat and then looked deep inside their brains after they passed away, found that certain vital immune cells worked differently in the brains of older people who were active compared to their more sedentary peers. Physical activity seemed to influence their brain’s health, their thinking abilities and whether they experienced the memory loss of Alzheimer’s disease. The findings add to growing evidence that when we move our bodies, we change our minds, no matter how advanced our age. Already, plenty of scientific evidence indicates that physical activity bulks up our brains. Older, sedentary people who begin walking for about an hour most days, for instance, typically add volume to their hippocampus, the brain’s memory center, reducing or reversing the shrinkage that otherwise commonly occurs there over the years. Active people who are middle-aged or older also tend to perform better on tests of memory and thinking skills than people of the same age who rarely exercise, and are nearly half as likely eventually to be diagnosed with Alzheimer’s disease. Almost as heartening, active people who do develop dementia usually show their first symptoms years later than inactive people do. But precisely how movement remodels our brains is still mostly mysterious, although scientists have hints from animal experiments. When adult lab mice and rats run on wheels, for example, they goose production of hormones and neurochemicals that prompt the creation of new neurons, as well as synapses, blood vessels and other tissues that connect and nurture those young brain cells. © 2021 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 5: The Sensorimotor System
Link ID: 28094 - Posted: 12.01.2021

Asher Mullard When the US Food and Drug Administration (FDA) approved biotechnology firm Biogen’s drug for Alzheimer’s disease in June, regulators hoped to usher in a new era of treatment for the neurodegenerative condition. But the decision followed an independent advisory committee’s near-unanimous vote to reject the drug, called aducanumab — and instead divided the community. Some researchers think that the approval will bolster the development of drugs for treating brain disease, but others see it as a blemish on the FDA’s integrity and an obstacle to progress. Pharmaceutical company Eli Lilly in Indianapolis hopes that its antibody donanemab, which works in a similar way to aducanumab, will have a better reception. The firm plans to finish submitting its drug candidate for FDA approval in the next few months, paving the way for a decision in the second half of 2022. Meanwhile, Biogen, based in Cambridge, Massachusetts, and its partner Eisai, based in Tokyo, are racing to complete the submission of data for another competitor, lecanemab. The regulatory fate of these therapeutic hopefuls could foretell the future of Alzheimer’s and shape neurodegenerative drug development programmes for years. According to the ‘amyloid hypothesis’ of Alzheimer’s disease, the build-up of a protein called amyloid-β in the brain causes neurodegeneration. Aducanumab and its would-be competitors clear clumps of amyloid-β from the brain. But clinical trials have not meaningfully demonstrated that these therapeutics slow memory loss or cognitive decline. This is a particular point of contention for aducanumab, an antibody drug that is now on the market for around US$56,000 per year, despite prematurely halted phase III trials and the messy data set that was submitted for approval. © 2021 Springer Nature Limited

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28077 - Posted: 11.17.2021

ByJocelyn Kaiser A common genetic variant called APOE4 raises a person’s risk of Alzheimer’s disease. It also poses a puzzle: If APOE4 is so bad for us, why hasn’t it been weeded out from the population? A new study finds that, surprisingly, the APOE4 variant has positive cognitive impacts: It may not only boost short-term memory, but also protect against subtle memory loss early in the course of Alzheimer’s disease. “There is something about the possession of an APOE4 allele which is providing some positive impacts on your cognitive function,” even in people whose brains are primed for Alzheimer’s, says neurologist Jonathan Schott of University College London (UCL), co-leader of the study. That could not only help explain why the variant persists, but also guide Alzheimer’s treatments, he says. The APOE gene codes for a protein called apolipoprotein E, which helps metabolize fats. About one in four people carry one copy of the version called APOE4 that roughly triples the risk for late-onset Alzheimer’s disease. (A few people have two copies of APOE4, which raises the risk 12-fold or more.) When a harmful gene remains in a population across hundreds of thousands of years, one possible explanation for its staying power is that one copy is beneficial. For example, people with one copy of the sickle cell gene are protected from malaria. Scientists have known for years that people with APOE4 are more likely to develop sticky amyloid protein plaques in their brains; many researchers think these may contribute to Alzheimer’s by triggering other changes that lead to neuronal death. Yet several small studies have hinted that APOE4 could have benefits, such as boosting fertility and cognition. Last year, a larger study found that APOE4 carriers across a range of ages perform slightly better than noncarriers on a test requiring them to quickly recall an object and its location. © 2021 American Association for the Advancement of Science.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28028 - Posted: 10.09.2021

By Judith Graham The approval of a controversial new drug for Alzheimer’s disease, Aduhelm, is shining a spotlight on mild cognitive impairment (MCI) — problems with memory, attention, language or other cognitive tasks that exceed changes expected with normal aging. After initially indicating that Aduhelm could be prescribed to anyone with dementia, the Food and Drug Administration now specifies that the prescription drug be given to individuals with MCI or early-stage Alzheimer’s, the groups in which the medication was studied. Yet this narrower recommendation raises questions. What does a diagnosis of MCI mean? Is Aduhelm appropriate for all people with MCI, or only some? And who should decide which patients qualify for treatment: dementia specialists or primary care physicians? Debate surrounds Aduhelm because its effectiveness has not been proved, its cost is high (an estimated $56,000 a year, not including expenses for imaging and monthly infusions), and its potential side effects are significant (41 percent of patients in the drug’s clinical trials experienced brain swelling and bleeding). Furthermore, an FDA advisory committee strongly recommended against Aduhelm’s approval, and Congress is investigating the process leading to the FDA’s decision. Medicare is studying whether it should cover the medication, and Veterans Affairs has declined to do so under most circumstances. Clinical trials for Aduhelm, developed by Biogen, based in Cambridge, Mass., excluded adults over 85, people taking blood thinners, people who had experienced a stroke, and those with cardiovascular disease or impaired kidney or liver function, among other conditions. If those criteria were broadly applied, 85 percent of people with MCI would not qualify for the drug, according to a research letter in the Journal of the American Medical Association.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28007 - Posted: 09.29.2021

Emma Yasinski Some genetic risk factors for alcohol use disorder overlap with those for neurodegenerative diseases like Alzheimer’s, scientists reported in Nature Communications on August 20. The study, which relied on a combination of genetic, transcriptomic, and epigenetic data, also offers insight into the molecular commonalities among these disorders, and their connections to immune disfunction. “By meshing findings from genome wide association studies . . . with gene expression in brain and other tissues, this new study has prioritized genes likely to harbor regulatory variants influencing risk of Alcohol Use Disorder,” writes David Goldman, a neurogenetics researcher at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), in an email to The Scientist. “Several of these genes are also associated with neurodegenerative disorders—an intriguing connection because of alcohol’s ability to prematurely age the brain.” Over the past several years, researchers have published a handful of massive genome-wide association studies (GWAS) studies identifying loci—regions of the genome that can contain 10 or more individual genes—that likely influence a person’s risk of developing an alcohol use disorder (AUD). In a study published two years ago, Manav Kapoor, a neuroscientist and geneticist at the Icahn School of Medicine at Mount Sinai and first author on the new paper, and his team found evidence that the immune system might be overactive in people with AUD, but the finding left him with more questions. The first was whether excessive drinking directly causes immune dysfunction, or if instead some people’s genetic makeup puts them at risk for both simultaneously. The second was which of the dozen or so genes at each previous GWAS-identified locus actually influences drinking behaviors. Lastly, he wanted to know if there is a genetic difference between people who consume higher numbers of alcoholic beverages per week but are not diagnosed with AUD and those who have received the diagnosis. © 1986–2021 The Scientist.

Related chapters from BN: Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain; Chapter 13: Memory and Learning
Link ID: 27995 - Posted: 09.18.2021