Toxic Fatty Acids Play a Critical Role in Brain Cell Death

Rodent studies led by researchers at NYU Grossman School of Medicine have found that cells called astrocytes, which normally nourish neurons, also release toxic fatty acids after neurons are damaged. The team suggests that this phenomenon is likely the driving factor behind most, if not all, diseases that affect brain function, as well as the natural breakdown of brain cells seen in aging.

Our findings show that the toxic fatty acids produced by astrocytes play a critical role in brain cell death and provide a promising new target for treating, and perhaps even preventing, many neurodegenerative diseases,” said Shane Liddelow, PhD, who is co-senior and corresponding author of the researchers’ published paper in Nature. In their report, which is titled, “Neurotoxic reactive astrocytes induce cell death via saturated lipids,” the team concluded. “The findings highlight the important role of the astrocyte reactivity response in CNS injury and neurodegenerative disease and the relatively unexplored role of lipids in CNS signaling.”

 

Astrocytes—star-shaped glial cells of the central nervous system (CNS)—undergo functional changes in response to CNS disease and injury, but the mechanisms that underlie these changes and their therapeutic relevance remain unclear, the authors noted. Interestingly, previous research has pointed to astrocytes as the culprits behind cell death seen in Parkinson’s disease and dementia, among other neurodegenerative diseases. “Astrocytes regulate the response of the central nervous system to disease and injury, and have been hypothesized to actively kill neurons in neurodegenerative disease,” the researchers stated. But while many experts believed that these cells release a neuron-killing molecule to clear away damaged brain cells, the identity of the toxin has remained a mystery.

The studies by Liddelow and colleagues now provide what they say is the first evidence that tissue damage prompts astrocytes to produce two kinds of fats, long-chain saturated free fatty acids and phosphatidylcholines. These fats then trigger cell death in damaged neurons. For their investigation, researchers analyzed the molecules released by astrocytes collected from rodents. “Previous evidence suggested that the toxic activity of reactive astrocytes is mediated by a secreted protein, so we first sought to identify the toxic agent by protein mass spectrometry of reactive versus control astrocyte conditioned medium (ACM),” they wrote.

Source: https://www.genengnews.com/

How to Reverse Age-related Brain Deterioration

Research from APC Microbiome Ireland (APCSFI Research Centre at University College Cork (UCC) published in the journal Nature Aging introduces a novel approach to reverse aspects of aging-related deterioration in the brain and cognitive function via the microbes in the gut.

As our population ages one of the key global challenges is to develop strategies to maintain healthy brain function. This ground-breaking research opens up a potentially new therapeutic avenues in the form of microbial-based interventions to slow down brain aging and associated cognitive problems. The work was carried out by researchers in the Brain-Gut-Microbiota lab in APC led by Prof John F. Cryan, Vice President for Research & Innovation, University College Cork as well as a Principal Investigator at APC Microbiome Ireland an SFI Research Centre, based in in University College Cork and Teagasc Moorepark.

There is a growing appreciation of the importance of the microbes in the gut on all aspects of physiology and medicine. In this latest mouse study the authors show that by transplanting microbes from young into old animals they could rejuvenate aspects of brain and immune function.

Prof John F. Cryan, says “Previous research published by the APC and other groups internationally has shown that the gut microbiome plays a key role in aging and the aging process. This new research is a potential game changer , as we have established that the microbiome can be harnessed to reverse age-related brain deterioration. We also see evidence of improved learning ability and cognitive function”.

Although very exciting Cryan cautions that “it is still early days and much more work is needed to see how these findings could be translated in humans”.

APC Director Prof Paul Ross stated that “This research of Prof. Cryan and colleagues further demonstrates the importance of the gut microbiome in many aspects of health, and particularly across the brain/gut axis where brain functioning can be positively influenced. The study opens up possibilities in the future to modulate gut microbiota as a therapeutic target to influence brain health”.

The study was led by co-first authors Dr Marcus Boehme along with PhD student Katherine E. Guzzetta, and Dr Thomaz Bastiaanssen.

Source: https://www.ucc.ie/

Reversal of Aging is Closer

The cure for aging has long been the Holy Grail of medicine. Emerging technologies, like the gene editing tool CRISPR, have opened the floodgates to what may be possible for the future of medical science. The key to slowing down aging, however, may lie in a simple and age-old technique. For the first time, Israeli scientists showed the reversal of aging in two key biological clocks in humans, by giving patients oxygen therapy in a pressurized chamber. The results appear in the journal Aging.

As you grow older and your cells continue to divide, sequences of DNA at the end of chromosomes, called telomeres, gradually become shorter. Once the telomeres become too short, the cell can no longer replicate and eventually dies. This isn’t necessarily a bad thing.

Telomere shortening can prevent rogue cancerous cells from multiplying uncontrollably, but unfortunately, this comes with the cost of genetic aging. These geriatric cells that can no longer divide are also known as senescent cells, which accumulate over the period of your life and are believed to be one of the leading causes of aging. In a clinical trial, 35 healthy adults aged 64 and older received 60 oxygen therapy sessions daily over the course of three months. The scientists collected the subjects’ blood samples prior to treatment, after the first and second months of the trial, and two weeks after the trial was over. None of the patients had any lifestyle, diet, or medication changes throughout the study, and yet their blood work showed significant increases in the telomere length of their cells and a decrease in the number of their senescent cells. This isn’t the first time doctors have put patients into pressurized oxygen chambers. Hyperbaric oxygen therapy (HBOT) has been used for almost a century to treat a number of illnesses, including decompression sickness in deep-sea divers and carbon monoxide poisoning.

The therapy involves breathing pure oxygen in a pressurized chamber, which causes blood and tissues in your body to become saturated with oxygen. Strangely enough, this can trigger similar physiological effects that occur when your body is starved of oxygen, known as hypoxia. While previous research shows these effects can stimulate your brain and increase your cognitive abilities, this is the first study to show the therapy may also reverse aging.

Since telomere shortening is considered the ‘Holy Grail’ of the biology of aging, many pharmacological and environmental interventions are being extensively explored in the hopes of enabling telomere elongation,” said study coauthor Shai Efrati, a professor at the Sackler School of Medicine at Tel Aviv University. The significant improvement of telomere length shown during and after these unique HBOT protocols provides the scientific community with a new foundation of understanding that aging can, indeed, be targeted and reversed at the basic cellular-biological level.

This also isn’t the first time scientists have claimed to reverse aging. Several studies using pharmacological drugs, such as danazol, have been shown to elongate telomeres. Additionally, lifestyle changes, including exercise and healthy diets, have been shown to have small effects on the growth of telomeres. “Until now, interventions such as lifestyle modifications and intense exercise were shown to have some inhibition effect on the expected telomere length shortening. However, what is remarkable to note in our study, is that in just three months of HBOT, we were able to achieve such significant telomere elongation—at rates far beyond any of the current available interventions or lifestyle modifications,” study coauthor Amir Hadanny, a neurosurgeon at the Sagol Center of Hyperbaric Medicine and Research in Israel, explained in the press release.

Source: https://www.popularmechanics.com/

How To Reverse Aging in the Brain

The aging global population is the greatest challenge faced by 21st-century healthcare systems. Even COVID-19 is, in a sense, a disease of aging. The risk of death from the virus roughly doubles for every nine years of life, a pattern that is almost identical to a host of other illnesses. But why are old people vulnerable to so many different things?

It turns out that a major hallmark of the aging process in many mammals is inflammation. By that, I don’t mean intense local response we typically associate with an infected wound, but a low grade, grinding, inflammatory background noise that grows louder the longer we live. This “inflammaging” has been shown to contribute to the development of atherosclerosis (the buildup of fat in arteries), diabetes, high blood pressure , frailty, cancer and cognitive decline.

Now a new study published in Nature reveals that microglia — a type of white blood cells found in the brain — are extremely vulnerable to changes in the levels of a major inflammatory molecule called prostaglandin E2 (PGE2). The team found that exposure to this molecule badly affected the ability of microglia and related cells to generate energy and carry out normal cellular processes.

Fortunately, the researchers found that these effects occurred only because of PGE2’s interaction with one specific receptor on the microglia. By disrupting it, they were able to normalize cellular energy production and reduce brain inflammation. The result was improved cognition in aged mice. This offers hope that the cognitive impairment associated with growing older is a transient state we can potentially fix, rather than the inevitable consequence of aging of the brain. Levels of PGE2 increase as mammals age for a variety of reasons — one of which is probably the increasing number of cells in different tissues entering a state termed cellular senescence. This means they become dysfunctional and can cause damage to tissue by releasing PGE2 and other inflammatory molecules.

But the researchers also found that macrophages — another type of white blood cells related to microglia — from people over the age of 65 made significantly more PGE2 than those from young people. Intriguingly, exposing these white blood cells to PGE2 suppressed the ability of their mitochondria — the nearest thing a cell has to batteries — to function. This meant that the entire pattern of energy generation and cellular behavior was disrupted.

Although PGE2 exerts its effects on cells through a range of receptors, the team were able to narrow down the effect to interaction with just one type (the “EP2 receptor” on the macrophages). They showed this by treating white blood cells, grown in the lab, with drugs that either turned this receptor on or off. When the receptor was turned on, cells acted as if they had been exposed to PGE2. But when they were treated with the drugs that turned it off, they recovered. That’s all fine, but it was done in a petri dish. What would happen in an intact body?

The researchers took genetically modified animals in which the EP2 receptor had been removed and allowed them to grow old. They then tested their learning and memory by looking at their ability to navigate mazes (something of a cliche for researchers) and their behavior in an “object location test.” This test is a bit like someone secretly entering your house, swapping your ornaments around on the mantelpiece and then sneaking out again. The better the memory, the longer the subject will spend looking suspiciously at the new arrangement, wondering why it has changed.

It turned out that the old genetically modified mice learned and remembered just as well as their young counterparts. These effects could be duplicated in normal old mice by giving them one of the drugs that could turn the EP2 receptor off for one month. So it seems possible that inhibiting the interaction of PGE2 with this particular receptor may represent a new approach to treating late-life cognitive disorders.

Source: https://www.theconversation.com/

Afternoon Napping Linked To Better Mental Agility

Taking a regular afternoon nap may be linked to better mental agility, suggests research published in the online journal General Psychiatry. It seems to be associated with better locational awareness, verbal fluency, and working memory, the findings indicate. Longer life expectancy and the associated neurodegenerative changes that accompany it, raise the prospect of dementia, with around 1 in 10 people over the age of 65 affected in the developed world.

As people age, their sleep patterns change, with afternoon naps becoming more frequent. But research published to date hasn’t reached any consensus on whether afternoon naps might help to stave off cognitive decline and dementia in older people or whether they might be a symptom of dementia.

The researchers explored this further in 2214 ostensibly healthy people aged at least 60 and resident in several large cities around China, including Beijing, Shanghai, and Xian. In all, 1534 took a regular afternoon nap, while 680 didn’t. All participants underwent a series of health checks and cognitive assessments, including the Mini Mental State Exam (MMSE) to check for dementia. The average length of night time sleep was around 6.5 hours in both groups. Afternoon naps were defined as periods of at least five consecutive minutes of sleep, but no more than 2 hours, and taken after lunch. Participants were asked how often they napped during the week; this ranged from once a week to every day.

The dementia screening tests included 30 items that measured several aspects of cognitive ability, and higher function, including visuo-spatial skills, working memory, attention span, problem solving, locational awareness and verbal fluency. The MMSE cognitive performance scores were significantly higher among the nappers than they were among those who didn’t nap. And there were significant differences in locational awareness, verbal fluency, and memory.

This is an observational study, and so can’t establish cause. And there was no information on the duration or timing of the naps taken, which may be important.

Source: https://www.eurasiareview.com/

Blocking Enzymes Reverse Alzheimer’s Memory Loss

Inhibiting certain enzymes involved in abnormal gene transcription may offer a way to restore memory loss associated with Alzheimer’s disease, a new study in mice suggests.

The findings could pave the way toward new treatments for Alzheimer’s disease (AD).

“By treating AD mouse models with a compound to inhibit these enzymes, we were able to normalize gene expression, restore neuronal function, and ameliorate cognitive impairment,” says senior author Zhen Yan, a professor in the department of physiology and biophysics in the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo.

Alzheimer’s disease alters the expression of genes in the prefrontal cortex, a key region of the brain controlling cognitive processes and executive functions.

When they focused on gene changes caused by epigenetic processes (those not related to changes in DNA sequences) such as aging, the researchers could reverse elevated levels of harmful genes that cause memory deficits in AD.

The current research extends the work the team reported in 2019 in the journal Brain, in which they reversed the loss or downregulation of genes beneficial to cognitive function in AD.

In the new paper in Science Advances, the team reports they reversed the upregulation of genes involved in impairing cognitive function.

http://www.buffalo.edu/

How To Fine-Tune Bacterial Metabolism To Boost Longevity

Studies have shown that gut microbes can influence several aspects of the host’s life, including aging. Given the complexity and heterogeneity of the human gut environment, elucidating how a specific microbial species contributes to longevity has been challenging.

To explore the influence of bacterial products on the aging process, scientists at Baylor College of Medicine and Rice University developed a method that uses light to directly control gene expression and metabolite production from bacteria residing in the gut of the laboratory worm Caenorhabditis elegans.

The team reports (“Optogenetic control of gut bacterial metabolism to promote longevity”) in eLife that green-light-induced production of colanic acid by resident Escherichia coli bacteria protected gut cells against stress-induced cellular damage and extended the worm’s lifespan. The researchers indicate that this method can be applied to study other bacteria and propose that it also might provide in the future a new way to fine-tune bacterial metabolism in the host gut to deliver health benefits with minimal side effects.

Illustration of bacteria in the intestine.

Gut microbial metabolism is associated with host longevity. However, because it requires direct manipulation of microbial metabolism in situ, establishing a causal link between these two processes remains challenging. We demonstrate an optogenetic method to control gene expression and metabolite production from bacteria residing in the host gut. We genetically engineer an E. coli strain that secretes colanic acid (CA) under the quantitative control of light,” the investigators wrote.

Using this optogenetically-controlled strain to induce CA production directly in the C. elegans gut, we reveal the local effect of CA in protecting intestinal mitochondria from stress-induced hyper-fragmentation. We also demonstrate that the lifespan-extending effect of this strain is positively correlated with the intensity of green light, indicating a dose-dependent CA benefit on the host.

“Thus, optogenetics can be used to achieve quantitative and temporal control of [the microbiome] metabolism in order to reveal its local and systemic effects on host health and aging. “We used optogenetics, a method that combines light and genetically engineered light-sensitive proteins to regulate molecular events in a targeted manner in living cells or organisms,” said co-corresponding author Meng Wang, PhD, professor of molecular and human genetics at the Huffington Center on Aging at Baylor.

Source: https://www.genengnews.com/

Exercise Is The Most Powerful Technique To Keep Our Brain Sharp

Unfortunately, we can’t go hard forever. But in the future, that might not be a problem: New research has revealed how to harness the cognitive benefits of a workout — without the actual workout. Scientists think this help slow aging in the brain. A study published Thursday in Science suggests the benefits of exercise run in the blood and may be able to be transferred from one swoll organism to another, less-swoll one.

Researchers report that unexercised, aged mice who received blood plasma donations from exercised mice improved their performance on spatial memory tests and showed fewer markers of inflammation related to aging. The authors suggest that these improvements occurred because exercise releases a series of circulating factors (like proteins) into the bloodstream. Saul Villeda, the study’s senior author and an assistant professor of anatomy at The University of California San Francisco, said that one specific protein abundant in the liver appears to be especially important. It’s called Glpd and it sends a crucial message to the body.

I think it’s sort of signaling to your body: repair yourself or restore yourself,” Villeda explains.

The study builds upon the larger idea that aging in the brain isn’t inevitable, and that the basic lifestyle tools we have to stave it off can be further honed to keep brains sharp into old age. It’s possibly a step towards an exercise pill that’s intended to keep the brain swole, not the body — though Villeda cautions that this is far in the future.

Numerous studies have suggested that exercise can help slow cognitive decline. The mechanisms for that differ, but a working idea is that exercise triggers a series of changes in the body, including the release of certain blood factors that may confer benefits, the study notes. Villeda calls the blood a “conduit” for all the organs in the body to communicate with one another, which suggests that might help transfer exercise-related benefits from one creature to another. In the study, a group of aged mice (18 months old) was given access to a running wheel all the time. Another group of sedentary mice was provided with nesting materials (to promote more chilling and less running). Then, blood plasma (which is the white-ish part of blood that contains all the circulating cells and proteins) was taken from each group and injected into two additional groups over three weeks.

The mice with their fresh runner-blood injections then performed a water-based maze test — they had to find a platform to get to safety — and a fear conditioning test. These tests are designed to test spatial learning memory. If you’ve ever had a moment when you realize that you can’t find your car in the parking lot anymore, you’ve experienced a lapse in that type of memory, Villeda explains.

All of a sudden, you might see this older individual using their car alarm to try and find their car because they can’t quite remember where their car was,” he says. “Those are the types of impairments that already are occurring with just normal age before you get dementia or disease.

The mice who received blood plasma transfusions from the exercised mice were faster to learn the location of the dry platforms in the maze compared to those that got plasma from sedentary mice. In the fear-based test, the mice were quicker to freeze in response to a context clue – suggesting that they were faster to learn what might cause them harm. In mouse-years, you might think of these aged mice as 70-year-olds, Villeda says. The improvements seen in the mice who received plasma donation were the equivalent of turning back the clock decades, he explains:

We’re reversing it probably back to the late 30s, early 40s. But that’s a significant improvement for these animals.”

This study suggests that these transfusions may help to preserve memory functions that once existed in younger animals, Villeda says — his team found that they were able to reverse some of the animal’s cognitive impairments. What these transfusions can not do is boost memory — the goal is to prevent decline, not add benefits.

Source: https://science.sciencemag.org/
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https://www.inverse.com/

Defective immune cells make us old

T cells are supposed to defend us from pathogens, but a new mouse study suggests they may also speed aging. Blocking inflammation caused by the cells or boosting their supply of a key metabolic molecule lessened the severity of some aging-related symptoms in rodents, raising the possibility these treatments could benefit older people. The discovery is “a fantastic result directly linking metabolism, inflammation, and aging,” says immunologist Kylie Quinn of RMIT University, Bundoora, in Australia. “They’ve done a really thorough job of making sure it’s the T cells” that are causing the mice to age quickly.

Our T cells let us down as we age, becoming weaker pathogen fighters. This decline helps explain why elderly people are more susceptible to infections and less responsive to vaccines. One reason T cells falter as we get older is that mitochondria, the structures that serve as power plants inside cells, begin to malfunction. But T cells might not just reflect aging. They could also promote it. Older people have chronic inflammation throughout the body, known as inflammaging, and researchers have proposed it spurs aging. T cells may stoke this process because they release inflammation-stimulating molecules.

To test that hypothesis, immunologist María Mittelbrunn of the University Hospital 12 October’s Health Research Institute and colleagues genetically modified mice to lack a protein in the mitochondria of their T cells. This alteration forces the cells to switch to a less efficient metabolic mechanism for obtaining energy.

By the time the rodents were 7 months old, typically the prime of life for a mouse, they already appeared to be in their dotage, the team reports today in Science. Compared with typical mice, the modified rodents were slow and sluggish. They had shrunken, weak muscles and were less resistant to infections. Like many elderly people, they suffered from weakened hearts and shed much of their body fatT cells from the altered mice poured out molecules that trigger inflammation, the team found, suggesting the cells could be partially responsible for the animals’ physical deterioration. “The immune system plays a role in increasing the velocity of aging,” Mittelbrunn says.

The scientists also tested whether they could slow the aging clock. First they dosed the mice with a drug that blocks tumour necrosis factor alpha (TNF-alpha), one of the inflammation-inducing molecules that T cells unleash; the treatment increased the animals’ grip strength, improved their performance in a maze, and boosted the heart’s pumping power.

Mittelbrunn and colleagues also gave the animals a compound that raises levels of nicotinamide adenine dinucleotide (NAD), a molecule that’s vital for metabolic reactions that enable cells to extract energy from food. NAD’s cellular concentrations typically decline with age, and the researchers found that ramping it up in the mice made them more active and strengthened their hearts.

Source: https://researchbank.rmit.edu.au/
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https://www.sciencemag.org/

How To Reverse Cellular Aging Process

Central to a lot of scientific research into aging are tiny caps on the ends of our chromosomes called telomeres. These protective sequences of DNA grow a little shorter each time a cell divides, but by intervening in this process, researchers hope to one day regulate the process of aging and the ill health effects it can bring. A Harvard team is now offering an exciting pathway forward, discovering a set of small molecules capable of restoring telomere length in mice. Telomeres can be thought of like the plastic tips on the end of our shoelaces, preventing the fraying of the DNA code of the genome and playing an important part in a healthy aging process. But each time a cell divides, they grow a little shorter. This sequence repeats over and over until the cell can no longer divide and dies.

This process is linked to aging and disease, including a rare genetic disease called dyskeratosis congenita (DC). This is caused by the premature aging of cells and is where the team focused its attention, hoping to offer alternatives to the current treatment that involves high-risk bone marrow transplants and which offers limited benefits.

One of the ways dyskeratosis congenita comes about is through genetic mutations that disrupt an enzyme called telomerase, which is key to maintaining the structural integrity of the telomere caps. For this reason, researchers have been working to target telomerase for decades, in hopes of finding ways to slow or even reverse the effects of aging and diseases like dyskeratosis congenita.

Once human telomerase was identified, there were lots of biotech startups, lots of investment,” says Boston Children’s Hospital’s Suneet Agarwal, senior investigator on the new study. “But it didn’t pan out. There are no drugs on the market, and companies have come and gone.

Source: https://news.harvard.edu/
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https://newatlas.com/