Experimental Drug Quickly Reduces Age-Related Mental Decline

The compound, known as ISRIB, holds potential for reversing numerous cognitive problems in humans. Mice are used in scientific studies due to having genes that are approximately 85 percent similar to the genes of humans.

Just a few doses of an experimental drug can reverse age-related declines in memory and mental flexibility in mice, according to a new study by UC San Francisco scientists. The drug, called ISRIB, has already been shown in laboratory studies to restore memory function months after traumatic brain injury (TBI), reverse cognitive impairments in Down Syndrome, prevent noise-related hearing loss, fight certain types of prostate cancer, and even enhance cognition in healthy animals.

In the new study, published December 1, 2020 in the open-access journal eLife, researchers showed rapid restoration of youthful cognitive abilities in aged mice, accompanied by a rejuvenation of brain and immune cells that could help explain improvements in brain function.

“ISRIB’s extremely rapid effects show for the first time that a significant component of age-related cognitive losses may be caused by a kind of reversible physiological ‘blockage’ rather than more permanent degradation,” said Susanna Rosi, PhD, Lewis and Ruth Cozen Chair II and professor in the departments of Neurological Surgery and of Physical Therapy and Rehabilitation Science.

“The data suggest that the aged brain has not permanently lost essential cognitive capacities, as was commonly assumed, but rather that these cognitive resources are still there but have been somehow blocked, trapped by a vicious cycle of cellular stress,” added Peter Walter, PhD, a professor in the UCSF Department of Biochemistry and Biophysics and a Howard Hughes Medical Institute investigator. “Our work with ISRIB demonstrates a way to break that cycle and restore cognitive abilities that had become walled off over time.”

Could Rebooting Cellular Protein Production Hold the Key to Aging and Other Diseases?

Walter has won numerous scientific awards, including the Breakthrough, Lasker and Shaw prizes, for his decades-long studies of cellular stress responses. ISRIB, discovered in 2013 in Walter’s lab, works by rebooting cells’ protein production machinery after it gets throttled by one of these stress responses — a cellular quality control mechanism called the integrated stress response (ISR; ISRIB stands for ISR InhiBitor).

The ISR normally detects problems with protein production in a cell — a potential sign of viral infection or cancer-promoting gene mutations — and responds by putting the brakes on cell’s protein-synthesis machinery. This safety mechanism is critical for weeding out misbehaving cells, but if stuck in the on position in a tissue like the brain, it can lead to serious problems, as cells lose the ability to perform their normal activities, Walter and colleagues have found.

In particular, recent animal studies by Walter and Rosi, made possible by early philanthropic support from The Rogers Family Foundation, have implicated chronic ISR activation in the persistent cognitive and behavioral deficits seen in patients after TBI, by showing that, in mice, brief ISRIB treatment can reboot the ISR and restore normal brain function almost overnight.

The cognitive deficits in TBI patients are often likened to premature aging, which led Rosi and Walter to wonder if the ISR could also underlie purely age-related cognitive decline. Aging is well known to compromise cellular protein production across the body, as life’s many insults pile up and stressors like chronic inflammation wear away at cells, potentially leading to widespread activation of the ISR.

“We’ve seen how ISRIB restores cognition in animals with traumatic brain injury, which in many ways is like a sped-up version of age-related cognitive decline,” said Rosi, who is director of neurocognitive research in the UCSF Brain and Spinal Injury Center and a member of the UCSF Weill Institute for Neurosciences. “It may seem like a crazy idea, but asking whether the drug could reverse symptoms of aging itself was just a logical next step.”

ISRIB Improves Cognition, Boosts Neuron and Immune Cell Function

In the new study, researchers led by Rosi lab postdoc Karen Krukowski, PhD, trained aged animals to escape from a watery maze by finding a hidden platform, a task that is typically hard for older animals to learn. But animals who received small daily doses of ISRIB during the three-day training process were able to accomplish the task as well as youthful mice, much better than animals of the same age who didn’t receive the drug.

The researchers then tested how long this cognitive rejuvenation lasted and whether it could generalize to other cognitive skills. Several weeks after the initial ISRIB treatment, they trained the same mice to find their way out of a maze whose exit changed daily — a test of mental flexibility for aged mice who, like humans, tend to get increasingly stuck in their ways. The mice who had received brief ISRIB treatment three weeks before still performed at youthful levels, while untreated mice continued to struggle.

To understand how ISRIB might be improving brain function, the researchers studied the activity and anatomy of cells in the hippocampus, a brain region with a key role in learning and memory, just one day after giving animals a single dose of ISRIB. They found that common signatures of neuronal aging disappeared literally overnight: neurons’ electrical activity became more sprightly and responsive to stimulation, and cells showed more robust connectivity with cells around them while also showing an ability to form stable connections with one another usually only seen in younger mice.

The researchers are continuing to study exactly how the ISR disrupts cognition in aging and other conditions and to understand how long ISRIB’s cognitive benefits may last. Among other puzzles raised by the new findings is the discovery that ISRIB also alters the function of the immune system’s T cells, which also are prone to age-related dysfunction. The findings suggest another path by which the drug could be improving cognition in aged animals, and could have implications for diseases from Alzheimer’s to diabetes that have been linked to heightened inflammation caused by an aging immune system.

“This was very exciting to me because we know that aging has a profound and persistent effect on T cells and that these changes can affect brain function in the hippocampus,” said Rosi. “At the moment, this is just an interesting observation, but it gives us a very exciting set of biological puzzles to solve.

ISRIB May Have Wide-Ranging Implications for Neurological Disease

It turns out that chronic ISR activation and resulting blockage of cellular protein production may play a role in a surprisingly wide array of neurological conditions. Below is a partial list of these conditions, based on a recent review by Walter and colleague Mauro Costa-Mattioli of Baylor College of Medicine, which could potentially be treated with an ISR-resetting agent like ISRIB:

  • Frontotemporal Dementia
  • Alzheimer’s Disease
  • Amyotrophic Lateral Sclerosis (ALS)
  • Age-related Cognitive Decline
  • Multiple Sclerosis
  • Traumatic Brain Injury
  • Parkinson’s Disease
  • Down Syndrome
  • Vanishing White Matter Disorder
  • Prion Disease

ISRIB has been licensed by Calico, a South San Francisco, Calif. company exploring the biology of aging, and the idea of targeting the ISR to treat disease has been picked up by other pharmaceutical companies, Walter says.

One might think that interfering with the ISR, a critical cellular safety mechanism, would be sure to have serious side effects, but so far in all their studies, the researchers have observed none. This is likely due to two factors, Walter says. First, it takes just a few doses of ISRIB to reset unhealthy, chronic ISR activation back to a healthier state, after which it can still respond normally to problems in individual cells. Second, ISRIB has virtually no effect when applied to cells actively employing the ISR in its most powerful form — against an aggressive viral infection, for example.

Naturally, both of these factors make the molecule much less likely to have negative side effects — and more attractive as a potential therapeutic. According to Walter: “It almost seems too good to be true, but with ISRIB we seem to have hit a sweet spot for manipulating the ISR with an ideal therapeutic window.

Cognitive Impairment in Mice With Dementia Reversed

It’s a significant development for treating that disease and those similar to it.

Reversing memory deficits and impairments in spatial learning is a major goal in the field of dementia research. A lack of knowledge about cellular pathways critical to the development of dementia, however, has stood in the way of significant clinical advance. But now, researchers at the Lewis Katz School of Medicine at Temple University (LKSOM) are breaking through that barrier. They show, for the first time in an animal model, that tau pathology — the second-most important lesion in the brain in patients with Alzheimer’s disease — can be reversed by a drug.

“We show that we can intervene after disease is established and pharmacologically rescue mice that have tau-induced memory deficits,” explained senior investigator Domenico Praticò, MD, Scott Richards North Star Foundation Chair for Alzheimer’s Research, Professor in the Departments of Pharmacology and Microbiology, and Director of the Alzheimer’s Center at Temple at LKSOM. The study, published online in the journal Molecular Neurobiology, raises new hope for human patients affected by dementia.

The researchers landed on their breakthrough after discovering that inflammatory molecules known as leukotrienes are deregulated in Alzheimer’s disease and related dementias. In experiments in animals, they found that the leukotriene pathway plays an especially important role in the later stages of disease.

“At the onset of dementia, leukotrienes attempt to protect nerve cells, but over the long term, they cause damage,” Dr. Praticò said. “Having discovered this, we wanted to know whether blocking leukotrienes could reverse the damage, whether we could do something to fix memory and learning impairments in mice having already abundant tau pathology.”

[…]

After 16 weeks of treatment, animals were administered maze tests to assess their working memory and their spatial learning memory. Compared with untreated animals, tau mice that had received zileuton performed significantly better on the tests. Their superior performance suggested a successful reversal of memory deficiency.

To determine why this happened, the researchers first analyzed leukotriene levels. They found that treated tau mice experienced a 90-percent reduction in leukotrienes compared with untreated mice. In addition, levels of phosphorylated and insoluble tau, the form of the protein that is known to directly damage synapses, were 50 percent lower in treated animals. Microscopic examination revealed vast differences in synaptic integrity between the groups of mice. Whereas untreated animals had severe synaptic deterioration, the synapses of treated tau animals were indistinguishable from those of ordinary mice without the disease.

[…]

The study is especially exciting because zileuton is already approved by the Food and Drug Administration for the treatment of asthma. “Leukotrienes are in the lungs and the brain, but we now know that in addition to their functional role in asthma, they also have a functional role in dementia,” Dr. Praticò explained.

“This is an old drug for a new disease,” he added. “The research could soon be translated to the clinic, to human patients with Alzheimer’s disease.”

Study: Alcohol Use Disorders are the Biggest Risk Factor for Dementia

Alcohol use disorders — defined by the authors as disorders involving hospitalization — must have a neurodegenerative effect at causing dementia.

Alcohol use disorders are the most important preventable risk factors for the onset of all types of dementia, especially early-onset dementia. This according to a nationwide observational study, published in The Lancet Public Health journal, of over one million adults diagnosed with dementia in France.

This study looked specifically at the effect of alcohol use disorders, and included people who had been diagnosed with mental and behavioural disorders or chronic diseases that were attributable to chronic harmful use of alcohol.

Of the 57,000 cases of early-onset dementia (before the age of 65), the majority (57%) were related to chronic heavy drinking.

The World Health Organization (WHO) defines chronic heavy drinking as consuming more than 60 grams pure alcohol on average per day for men (4-5 Canadian standard drinks) and 40 grams (about 3 standard drinks) per day for women.

As a result of the strong association found in this study, the authors suggest that screening, brief interventions for heavy drinking, and treatment for alcohol use disorders should be implemented to reduce the alcohol-attributable burden of dementia.

“The findings indicate that heavy drinking and alcohol use disorders are the most important risk factors for dementia, and especially important for those types of dementia which start before age 65, and which lead to premature deaths,” says study co-author and Director of the CAMH Institute for Mental Health Policy Research Dr. Jürgen Rehm. “Alcohol-induced brain damage and dementia are preventable, and known-effective preventive and policy measures can make a dent into premature dementia deaths.”

Dr. Rehm points out that on average, alcohol use disorders shorten life expectancy by more than 20 years, and dementia is one of the leading causes of death for these people.

For early-onset dementia, there was a significant gender split. While the overall majority of dementia patients were women, almost two-thirds of all early-onset dementia patients (64.9%) were men.

Alcohol use disorders were also associated with all other independent risk factors for dementia onset, such as tobacco smoking, high blood pressure, diabetes, lower education, depression, and hearing loss, among modifiable risk factors. It suggests that alcohol use disorders may contribute in many ways to the risk of dementia.

“As a geriatric psychiatrist, I frequently see the effects of alcohol use disorder on dementia, when unfortunately alcohol treatment interventions may be too late to improve cognition,” says CAMH Vice-President of Research Dr. Bruce Pollock. “Screening for and reduction of problem drinking, and treatment for alcohol use disorders need to start much earlier in primary care.” The authors also noted that only the most severe cases of alcohol use disorder — ones involving hospitalization — were included in the study. This could mean that, because of ongoing stigma regarding the reporting of alcohol-use disorders, the association between chronic heavy drinking and dementia may be even stronger.

Curcumin Found to Improve Memory in Study of Those With Mild Memory Loss

Good research on countering age-related cognitive problems with a simple remedy of curcumin. This is especially important when pharmaceutical corporations such as Pfizer are doing less research on Alzheimer’s and dementia.

The sample size of this study may also be relatively small, but its methodology looks rigorous enough, and turmeric has already been found to have considerable health benefits.

Daily consumption of a certain form of curcumin — the substance that gives Indian curry its bright color — improved memory and mood in people with mild, age-related memory loss, according to the results of a study conducted by UCLA researchers.

The research, published online Jan. 19 in the American Journal of Geriatric Psychiatry, examined the effects of an easily absorbed curcumin supplement on memory performance in people without dementia, as well as curcumin’s potential impact on the microscopic plaques and tangles in the brains of people with Alzheimer’s disease.

Found in turmeric, curcumin has previously been shown to have anti-inflammatory and antioxidant properties in lab studies. It also has been suggested as a possible reason that senior citizens in India, where curcumin is a dietary staple, have a lower prevalence of Alzheimer’s disease and better cognitive performance.

“Exactly how curcumin exerts its effects is not certain, but it may be due to its ability to reduce brain inflammation, which has been linked to both Alzheimer’s disease and major depression,” said Dr. Gary Small, director of geriatric psychiatry at UCLA’s Longevity Center and of the geriatric psychiatry division at the Semel Institute for Neuroscience and Human Behavior at UCLA, and the study’s first author.

The double-blind, placebo-controlled study involved 40 adults between the ages of 50 and 90 years who had mild memory complaints. Participants were randomly assigned to receive either a placebo or 90 milligrams of curcumin twice daily for 18 months.

[…]

The people who took curcumin experienced significant improvements in their memory and attention abilities, while the subjects who received placebo did not, Small said. In memory tests, the people taking curcumin improved by 28 percent over the 18 months. Those taking curcumin also had mild improvements in mood, and their brain PET scans showed significantly less amyloid and tau signals in the amygdala and hypothalamus than those who took placebos.

[…]

The researchers plan to conduct a follow-up study with a larger number of people. That study will include some people with mild depression so the scientists can explore whether curcumin also has antidepressant effects. The larger sample also would allow them to analyze whether curcumin’s memory-enhancing effects vary according to people’s genetic risk for Alzheimer’s, their age or the extent of their cognitive problems.

“These results suggest that taking this relatively safe form of curcumin could provide meaningful cognitive benefits over the years,” said Small, UCLA’s Parlow-Solomon Professor on Aging.

Study: First Brain Training Exercise Linked to Dementia Prevention Found

A related and thought provoking quote: “Our mind is all we’ve got. Not that it won’t lead us astray sometimes, but we still have to analyze things out within ourselves.” — Bobby Fischer

Aging research specialists have identified, for the first time, a form of mental exercise that can reduce the risk of dementia.

The cognitive training, called speed of processing, showed benefits up to 10 years after study participants underwent the mental exercise program, said Frederick W. Unverzagt, PhD, professor of psychiatry at Indiana University School of Medicine.

The proportion of participants who underwent the training and later developed dementia was significantly smaller than among those who received no cognitive training, the researchers said.

There were measurable benefits even though the amount of training was small and spread out over time: 10 one-hour sessions over six weeks initially and up to eight booster sessions after that.

Research Finds Where the Earliest Signs of Alzheimer’s Occur in the Brain

This discovery has considerable potential for stopping the devastation Alzheimer’s often induces in those who develop the disease.

Researchers at Lund University in Sweden have for the first time convincingly shown where in the brain the earliest signs of Alzheimer’s occur. The discovery could potentially become significant to future Alzheimer’s research while contributing to improved diagnostics.

In Alzheimer’s, the initial changes in the brain occur through retention of the protein, ?-amyloid (beta-amyloid). The process begins 10-20 years before the first symptoms become noticeable in the patient.

In Nature Communications, a research team headed by Professor Oskar Hansson at Lund University has now presented results showing where in the brain the initial accumulation of ?-amyloid occurs. It is in the inner parts of the brain, within one of the brain’s most important functional networks — known as the default mode network.

“A big piece of the puzzle in Alzheimer’s research is now falling into place. We previously did not know where in the brain the earliest stages of the disease could be detected. We now know which parts of the brain are to be studied to eventually explain why the disease occurs,” says Sebastian Palmqvist, associate professor at Lund University and physician at Skåne University Hospital.

The default mode network is one of several networks, each of which has a different function in the brain. It is most active when we are in an awake quiescent state without interacting with the outside world, for example, when daydreaming. The network belongs to the more advanced part of the brain. Among other things, it processes and links information from lower systems.

[…]

The difficulty of determining which individuals are at risk of developing dementia later in life, in order to subsequently monitor them in research studies, has been an obstacle in the research world. The research team at Lund University has therefore developed a unique method to identify, at an early stage, which individuals begin to accumulate ?-amyloid and are at risk.

The method combines cerebrospinal fluid test results with PET scan brain imaging. This provides valuable information about the brain’s tendency to accumulate ?-amyloid.

In addition to serving as a roadmap for future research studies of Alzheimer’s disease, the new results also have a clinical benefit:

“Now that we know where Alzheimer’s disease begins, we can improve the diagnostics by focusing more clearly on these parts of the brain, for example in medical imaging examinations with a PET camera,” says Oskar Hansson, professor at Lund University, and medical consultant at Skåne University Hospital.

Although the first symptoms of Alzheimer’s become noticeable to others much later, the current study shows that the brain’s communication activity changes in connection with the early retention of ?-amyloid. How, and with what consequences, will be examined by the research team in further studies.