Tag: ageing

Categories : Ageing Diet and Nutrition Neurodegenerative DiseasesTags :

A Mediterranean Diet Keeps Dementia at Bay

On By ModernMedia
A dish full of vegetables which could be in a Mediterranean diet.

Researchers have reported that a Mediterranean diet may reduce the risk of developing dementia and cognitive loss, helping preserve memory functions as people age.

Specifically, the diet appears to lower the level of amyloid and tau proteins that are linked with dementia. People following the Mediterranean diet, already noted for its numerous health benefits, scored better on memory tests than those who were not following the diet.

The first of these proteins, amyloid protein, forms plaques in the brain, whereas the second, tau protein, forms tangles. Both are present in the brains of people with Alzheimer’s, though they are not uncommon in the brains of healthy older people, too.

“These results add to the body of evidence that shows what you eat may influence your memory skills later on,” said study author Tommaso Ballarini, PhD, of the German Center for Neurodegenerative Diseases in Bonn, Germany. He adds:

Studies have linked good health with the foods that people living in Greece, Spain, and Italy ate before the 1960s. This diet consists primarily of vegetables and fruits, nuts and seeds, legumes, potatoes, whole grain foods, seafood, extra virgin olive oil, and wine in moderation. Poultry, eggs and dairy products are present to a limited extent, while red meat, added sugar, refined grains and oils, and processed foods are typically lacking in a Mediterranean diet.

Kristin Kirkpatrick, a dietitian at Cleveland Clinic told Medical News Today that the contents of a Mediterranean diet offers beneficial “omega-3 fatty acids, polyphenols, specific minerals, fiber, and protein” that “may support the brain’s health and protection throughout the years.”

However, Kirkpatrick cautioned that, “A diet, even one with strong clinical data on its benefit, is only as healthy as the individuals who choose its structure.”

Sensible portion sizes are important, she noted and warned against the “consumption of processed foods that are marketed as heart-healthy or contain the components seen in a traditional Mediterranean approach.”

The investigators recruited 512 individuals from the German Centre for Neurodegenerative Diseases’ Longitudinal Cognitive Impairment and Dementia StudyTrusted Source. Participant  assessments showed that 343 were at a higher risk of developing Alzheimer’s disease while the other 169 people were “cognitively normal.”

Participants filled in questionnaires regarding the food they ate the previous month and the investigators asked them to record their intake of 148 specific food items. Participants were scored on their diet’s similarity to a Mediterranean diet, the most similar receiving a 9 and the least similar a 1. Since this was a self-reported study on eating habits, errors or misrepresentations are possible.

Individuals also took cognitive tests designed to detect the progression of Alzheimer’s disease. The tests assessed five areas: memory, working memory, language, executive functions, and visuospatial abilities. MRI brain scans determined each individual’s brain volume.

Finally, the researchers analyzed spinal fluid from a subsample of 226 participants who gave their consent, assessing the presence and amounts of the two biomarker proteins: amyloid and tau.

After adjusting for sex, age, and education, the scientists identified several clear links between better cognitive health and a Mediterranean diet.

The investigators  reported that:

  • Every dietary score point lower than 9 was linked to almost 1 year of the brain ageing that occurs in Alzheimer’s disease progression.
  • Participants who most closely followed the Mediterranean diet had fewer amyloid and tau protein biomarkers in their spinal fluid than those who had lower dietary scores.
  • People on the Mediterranean diet scored better on memory tests than people who were not.

Dr Ballarani concluded that, “More research is needed to show the mechanism by which a Mediterranean diet protects the brain from protein buildup and loss of brain function, but findings suggest that people may reduce their risk for developing Alzheimer’s by incorporating more elements of the Mediterranean diet into their daily diets.”

Source: Medical News Today

Categories : AgeingTags :

Older People That Feel Younger Live Longer

On By ModernMedia
A smiling elderly woman. Photo by Loren Joseph on Unsplash

A new study has found that older people who feel younger are generally more healthy. Such people have greater sense of well-being, better cognitive functioning, less inflammation, lower risk of hospitalisation and even live longer than their older-feeling peers. 

As Francis Bacon once said, “I will never be an old man. To me, old age is always 15 years older than I am.” Studies have shown that feeling younger than one’s chronological age has been known to have some health benefits. A twin study in Denmark showed that perceived age, correlated significantly with physical and cognitive functioning as well as with leucocyte telomere length — which prevents cells from becoming unable to divide.

Researchers from the German Centre of Gerontology analysed three years of data from 5039 participants in the German Ageing Survey, a longitudinal survey of German residents of age 40 and older. The survey had questions about the amount of perceived stress in peoples’ lives and their functional health—how well they could conduct daily activities such as dressing and walking. Participants also indicated their subjective age by answering the question, “How old do you feel?”

Participants with more reported stress tended to have a more rapid decline in functional health over three years, and that association between stress and functional health decline was stronger for chronologically older participants.

Among people who felt younger than their chronological age, there was a weaker association between stress and functional health decline. This protective effect was strongest among the oldest participants.

“Generally, we know that functional health declines with advancing age, but we also know that these age-related functional health trajectories are remarkably varied. As a result, some individuals enter old age and very old age with quite good and intact health resources, whereas others experience a pronounced decline in functional health, which might even result in need for long-term care,” said lead author Markus Wettstein, PhD, who is now at University of Heidelberg. “Our findings support the role of stress as a risk factor for functional health decline, particularly among older individuals, as well as the health-supporting and stress-buffering role of a younger subjective age.”

The researchers said their findings suggest that helping older people feel younger could mitigate the negative effects stress and improving health—though further study is needed to help determine what kind of interventions would work best. Dr Wettstein gave examples of such efforts, such as messaging campaigns to counteract ageism and negative age stereotypes and to promote ageing in a positive light could help people feel younger. More general stress-reduction interventions and stress management training could also prevent functional health loss among older adults.

Dr Wettstein said that there needs to be further studies to find the ideal gap between subjective and chronological age, as previous research has suggested that, up to a point, it’s helpful to feel younger, but those benefits decrease as the gap between subjective and chronological age increases. “Feeling younger to some extent might be adaptive for functional health outcomes, whereas ‘feeling too young’ might be less adaptive or even maladaptive,” he said.

Source: Medical Xpress

Journal information: Markus Wettstein et al, Feeling younger as a stress buffer: Subjective age moderates the effect of perceived stress on change in functional health., Psychology and Aging (2021). DOI: 10.1037/pag0000608

Categories : Ageing Cardiovascular Disease Neurodegenerative DiseasesTags :

Mitochondria Dump DNA into Cells, Triggering Inflammation

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Researchers have discovered that when building blocks for DNA in cells are in short supply, mitochondria— the powerhouses of cells — release their own DNA, triggering an inflammatory response. Targeting this process can now open up new avenues of treatment into ageing-related diseases.

Mitochondria, the producers of energy for cells, , have their own genetic material: mitochondrial DNA. In certain situations, however, mitochondria are known to release their DNA into the interior of the cell, provoking a reaction from the cell’s own immune system. Some cardiac and neurodegenerative diseases as well as the ageing process are associated with the mitochondrial genome.

To find out when mitochondria release their DNA, the researchers have focused on the mitochondrial protein YME1L. “In cells lacking YME1L, we observed the release of mitochondrial DNA into the cell interior and a related immune response in the cells,” explained Thomas MacVicar, one of the study’s two first authors.  
“If the cells lack YME1L, there is a deficiency of DNA building blocks inside the cell,” he continued. “This deficiency triggers the release of mitochondrial DNA, which in turn causes an inflammatory response in the cell: the cell stimulates similar inflammatory reactions as it does during a bacterial or viral infection. If we add DNA building blocks to the cells from the outside, that also stops the inflammation.”

This newly discovered link between cellular inflammatory response and the metabolism of DNA building blocks could have far-reaching consequences, MacVicar explained. “Some viral inhibitors stop the production of certain DNA building blocks, thereby triggering an inflammatory response. The release of mitochondrial DNA could be a crucial factor in this, contributing to the effect of these inhibitors,” he said. 
Mitochondrial DNA is associated with a number of ageing-associated inflammatory diseases, including cardiac and neurodegenerative diseases, as well as obesity and cancer. The authors hope that new therapeutic opportunities in such diseases can be created by modulating the metabolism of DNA building blocks.

Source: Medical Xpress

Journal information: Hans-Georg Sprenger et al, Cellular pyrimidine imbalance triggers mitochondrial DNA–dependent innate immunity, Nature Metabolism (2021). DOI: 10.1038/s42255-021-00385-9

Categories : Ageing Cancer Mental HealthTags :

Loneliness in Middle-aged Men Tied to Cancer Risk

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Older man sitting alone on beach. Photo by Engin Akyurt from Pexels

A recent study by the University of Eastern Finland shows that loneliness among middle-aged men is associated with an increased risk of cancer.

Cancer is the second leading cause of death around the world, and in high-income countries it has become the main cause. Recent scientific evidence demonstrates that stress plays a positive role in cancer initiation, progression and cancer metastasis, as well as a negative role for anti-tumor immune function and therapy response.

“It has been estimated, on the basis of studies carried out in recent years, that loneliness could be as significant a health risk as smoking or overweight. Our findings support the idea that attention should be paid to this issue,” said project researcher Siiri-Liisi Kraav from the University of Eastern Finland.

The study was launched in the 1980s with middle-aged men from eastern Finland participating. To avoid reverse causality, individuals who already had a cancer diagnosis or received a cancer diagnosis within two years after the baseline data collection were excluded from the analysis. The  2570 eligible participants had their health and mortality monitored on the basis of register data through to the present. Follow-up lasted an average of 20.44 years, and the average age of cancer diagnosis was 69.96 years.
Factors accounted for included age, socio-economic status, lifestyle, sleep quality, depression symptoms, body mass index, heart disease and other risk factors.

During the follow-up, 649 men (25% of participants) developed cancer, and 283 men (11%) died of cancer. Loneliness was associated with a roughlt 10% increased cancer risk. In addition, cancer mortality was higher in cancer patients who were unmarried, widowed or divorced at baseline.
Based on these results, the researchers recommended that consideration of loneliness and social relationships should be an important part of comprehensive health care and disease prevention. The findings were published in Psychiatry Research.

“Awareness of the health effects of loneliness is constantly increasing. Therefore, it is important to examine, in more detail, the mechanisms by which loneliness causes adverse health effects. This information would enable us to better alleviate loneliness and the harm caused by it, as well as to find optimal ways to target preventive measures,” concluded Kraav.

Source: University of Eastern Finland

Journal information: Kraav, S., Lehto, S.M., Kauhanen, J., Hantunen, S., Tolmunen, T., 2021. Loneliness and social isolation increase cancer incidence in a cohort of Finnish middle-aged men. A longitudinal study. Psychiatry Research: https://doi.org/10.1016/j.psychres.2021.113868

Categories : AgeingTags :

Dermal Fillers Can Provide Minor Facelifts

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A new study using 3D imaging shows that dermal fillers can also provide some ‘lifting’ effects, as well as their normal ‘volumising’ effects in facial rejuvenation therapy. 

Dermal fillers are ranked second of the top five non-surgical cosmetic procedures, behind botulinum toxin injections. While dermal fillers have been increasing in popularity, plastic surgeons are trying to work out the best application for facial rejuvenation without surgery. Most studies have used subjective rating systems with little generalisability as a result.

The results of a recent study showed that in addition to ‘volumising’ effects, dermal fillers may also have variable ‘lifting’ effects. Sebastian Cotofana, MD, PhD, of the Mayo Clinic,and colleagues came up with a study to measure the true lifting effect of soft tissue fillers.

In this experimental study, the researchers performed standardised dermal filler injections in facial cadaver specimens, in the areas commonly targeted for facial rejuvenation: the forehead and temple; the midface region, including both the medial (central) and the lateral (sides) areas; and around the mouth and jawline.

Dr Cotofana and colleagues performed before-and-after 3D scans of the facial surface to measure the effects of the injections. 

Dermal filler injections showed significant increases in local soft tissue volume in central areas of the face, consistent with the well-established clinical effects of ‘injectable’ treatment in the forehead, midface, and mouth and chin areas.

Local lifting effects were also seen from central facial injections, with up to one millimetre of vertical ‘lift’ in the forehead area, but this was not seen in the other facial areas.

Injections in lateral facial areas such as the jawline also resulted in local volumising and lifting effects. These lateral facial injections also created ‘additional regional lifting effects’ in neighbouring facial areas. Temple injections resulted in a small but significant lifting effect on the lateral midface and jawline, for example.

Combined injection techniques provided even greater benefits. Added to deep filler injection, a superficial temple injection technique produced an additional 17.5% increase in the lifting effect of the temple, plus a 100% increase in the jawline lifting effect.

“These results indicate that lateral face injections co-influence adjacent lateral facial regions and can thus induce regional lifting effects,” wrote Dr Cotofana and coauthors. The results are consistent with previous knowledge of the in-depth anatomy of the face: filler injections may lead to a change in tension of the connective tissue (fascia) under the skin, resulting in “re-positioning” of the upper skin layers.

In this way, filler injections can provide a small but significant lifting effect in a minimally invasive, repeatable procedure, although they are not as effective as plastic surgery. Besides providing confirmation on previous findings on the lifting effects of facial injectables, the study also “broadens their applicability to the total lateral face…to achieve local and regional lifting effects.”

Source: News-Medical.Net
Journal information: Haidar, R., et al. (2021) Quantitative Analysis of the Lifting Effect of Facial Soft-Tissue Filler Injections. Plastic and Reconstructive Surgery. doi.org/10.1097/PRS.0000000000007857.

Categories : AgeingTags :

Leg Motion Can Protect Against Leg Swelling in the Elderly

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A study from Kanazawa University in Japan has shown that leg swelling can be reduced in the elderly as the muscle pumping action of the leg is as effective in people of all ages.

Chronic lower-limb oedema (CLO) — the permanent accumulation of fluid in the leg — often occurs in elderly people. The condition leads to various physical and mental problems, including difficulty in walking or moving, fatigue and anxiety. Lack of physical activity, associated with a decrease in muscle pump action is one of the causes of CLO.

Leg muscles can act as a blood pump: when contracted, the muscle squeezes veins together, forcing blood to flow. But it was not known whether muscle pump action changes as people age had not been thoroughly investigated. Now, Junko Sugama from Kanazawa University and colleagues have addressed this issue. In addition, they studied the effect of leg posture on the muscle pump action.

For their study, the researchers recruited 76 healthy volunteers, categorised into young, middle-aged and old, with average ages of 24, 47 and 72 years, respectively. To investigate blood flow and visualise the morphology of muscles and veins at a given position along the leg, the researchers used MRI cross-section images at 21 positions in the calf region.

To assess the effect of leg motion, subjects were asked to perform plantar flexion (pointing the foot downwards) every 2 seconds for a minute, and MRI images were taken before and after the exercise. This procedure was repeated over three different body positions: supine, sitting and standing.

The scientists found that for all postures, blood flow increased after the exercise, implying that the latter promotes muscle pump action. The blood flow velocity was observed to increase most for the standing posture (90-135%), followed by the supine (55-90%) and sitting (30-40%) postures. No age difference was seen in the flow changes, however the elderly patients had exercise habits, the researchers pointed out.

The researchers suggested that nurse measurement of muscle pump action is useful for deciding whether intervention exercise is necessary to prevent CLO but an easier measurement tool than MRI is needed.

Additional studies are needed, such as adapting the measurement equipment so that it can be applied to elderly people with reduced mobility. The scientists nevertheless concluded that for their set of subjects, “no difference was found in the changes in muscle pump action with age”, and that “elderly people may be able to maintain their muscle pump action when they have exercise habits”.

Source: News-Medical.Net

Journal reference: Fujii, T., et al. (2021) Gravity magnetic resonance imaging measurement of muscle pump change accompanied by aging and posture. Japan Journal of Nursing Science. doi.org/10.1111/jjns.12407.

Categories : Neurodegenerative DiseasesTags :

Exercise Slows Cognitive Decline in APOE4-related Parkinson’s Disease

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Results from a longitudinal study showed physical activity reduced  cognitive decline in early APOE4-related Parkinson’s disease.

Jin-Sun Jun, MD, of Hallym University in Seoul, and colleagues in Neurology presented the findings of a longitudinal study on a group of 173 recently diagnosed Parkinson’s patients. Of this group, those who with an apolipoprotein E ε4 (APOE4) allele had faster cognitive decline on the 30-point Montreal Cognitive Assessment (MoCA) scale than noncarriers (estimate -1.33, 95% CI -2.12 to -0.47, P=0.002). However, among the APOE4 carriers, higher physical activity was related to slower cognitive decline (estimate 0.007, 95% CI 0.003-0.011, P=0.001)..

Dr Jun noted that this reflects a number of studies that have demonstrated that Parkinson’s patients who exercise regularly show better clinical outcomes, including motor and cognitive function.

“These observations are supported by epidemiological data showing a link between physical activity and decreased risk for Parkinson’s disease,” Dr Jun told MedPage Today. “Because previous data indicate that physical activity modifies the APOE4 effect on the development and progression of Alzheimer’s disease, we hypothesized that physical activity also plays a role in modulating the association between APOE4 and cognition in Parkinson’s disease.”

Genetic factors interact with physical activity on other health outcomes, noted Jacob Raber, PhD, of Oregon Health and Science University in Portland, and colleagues, in an accompanying editorial.

“If similar gene-by-physical activity interactions were identified in Parkinson’s disease, they could pave the way for personalized treatment,” Raber and colleagues wrote. “While the effects of APOE4 on promoting beta-amyloid and tau pathology are well-established, recent studies show that APOE4 is also associated with more profound pathology of alpha-synuclein and higher measures of cognitive burden, both in mouse models and in humans with Parkinson’s disease.”

In their study, the researchers followed recently diagnosed patients in the Parkinson’s Progression Markers Initiative cohort who were not treated for Parkinson’s and who had abnormal dopamine transporter (DAT) imaging.

Self-reported physical activity was begun 2 years after enrollment and scored on the Physical Activity Scale of the Elderly. Cognitive function was measured annually with the MoCA, which is well-suited for Parkinson’s patients, and DAT imaging was performed at years 2 and 4. Assessments performed at years 2, 3, and 4 were used for analysis.

There was no significant interaction seen between physical activity and APOE4 involving change in striatal DAT activities. This suggests that striatal dopaminergic function may not be a major factor in physical activity’s protective effect on APOE4-related cognitive decline, Dr Jun and colleagues noted. “These negative results may be explained by the modest effect of APOE4 on the nigrostriatal dopaminergic system,” they wrote. “Furthermore, our follow-up duration may be too short to comprehend the impact of APOE4 on this system, considering the slow progressive nature of alpha-synucleinopathy.”

The researchers also pointed out that the exercise could offer benefits through mechanisms unrelated to the disease. “Although we cannot conclude what types or amounts of exercise help to slow progression from this study design, even non-high-intensity physical activity positively modified the impact of APOE4 on cognitive function,” Jun said.

The study’s limitations included physical activity being self-reported, cognitive function being based only on MoCA scores, and a short follow-up time. Though motor scores in the off-medication state were adjusted for, physical activity may have been less due to disease progression.

Source: MedPage Today

Categories : Skeletal SystemTags :

Osteoporosis Rates are Increasing in US Women

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Osteoporosis is present in Almost one in five American women aged 50 and older, according to data from the National Health and Nutrition Examination Survey (NHANES), and the osteoporosis rates are increasing.

Neda Sarafrazi, PhD, of the National Center for Health Statistics (NCHS) in Hyattsville, Maryland, and colleagues reported the findings in an NCHS Data Brief.

Osteoporosis is defined as bone mineral density (BMD) value at least 2.5 standard deviations below young-adult average at the femoral neck or lumbar spine was present, and was measured in NHANES with dual x-ray absorption dosimetry.

In cross-sectional survey data from 2017-2018, 19.6% of women 50 and older had osteoporosis at the femoral neck, lumbar spine, or both. In men, the age-adjusted prevalence was only 4.4% of men 50 and older.

All in all, osteoporosis was present in 12.6% of all American adults 50 and older, which was defined as a bone mineral density (BMD) value at least 2.5 standard deviations below the average for young adults at the femoral neck or lumbar spine.

Osteoporosis, as to be expected, was far more common among older adults, affecting 17.7% of all men and women 65 and older, versus 8.4% of those ages 50-64. In women ages 65 and older, the prevalence was 27% and at ages 50-64 was 13.1%. In men, prevalence values were 5.7% in those 65 and older and 3.3% for those 50-64.

Sarafrazi’s team found that osteoporosis had become slightly more prevalent over the years. In 2007-2008, 9.4% of Americans 50 and older had osteoporosis. While rates remained steady throughout for men, a big uptick of 5 percentage points was seen for women.

“Monitoring the prevalence of osteoporosis and low bone mass may inform public health programs that focus on reducing or preventing osteoporosis and its consequences,” suggested Sarafrazi’s group. “Healthy People 2020 has a goal of 5.3% or less for the prevalence of osteoporosis at the femur neck for adults aged 50 and over.”

“In the United States, the prevalence of osteoporosis among adults aged 50 and over at the femur neck only was 6.3% and has not met the 2020 goal,” they stressed.

The data also revealed high rates of low bone mass, a precursor of osteoporosis, defined as BMD of 1 to 2.5 standard deviations below the average for young adults.

Among all adults ages 50 and older, 43.1% had low bone mass at the femoral neck, lumbar spine, or both. Among women, prevalence was 51.5% and among men 33.5% .

The overall rate reached 47.5% in those 65 and older. However, older age seemed to be less of a factor for women, with almost no difference between the 50-64 and 65-plus age groups.

However, the prevalence rates of low bone mass in both sexes held steady during the decade between 2007-2008 and 2017-2018.  

Source: MedPage Today

Journal information: Sarafrazi N, et al “Osteoporosis or low bone mass in older adults: United States, 2017–2018” NCHS Data Brief 2021; No 405.

Categories : Ageing Immune SystemTags :

Study Shows That Viral Infections Affect Immune System like Ageing

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A study from the Buck Institute and Stanford University suggests that chronic viral infections leave an impact on the human immune system, similar to those seen during ageing.

Using systems immunology and artificial intelligence, researchers profiled and compared immune responses in a cohort of aging individuals, people with HIV on long-term antiretroviral therapy, and people infected with hepatitis C (HCV) before and after the virus was treated with sofosbuvir, a drug with a 97% cure rate. Shared immune system alterations include T cell memory inflation, upregulation of intracellular signaling pathways of inflammation, and diminished sensitivity to cytokines in lymphocytes and myeloid cells.

“Chronic inflammation stemming from immune system dysfunction is associated with many of the diseases of ageing,” said senior author David Furman, PhD, Buck Institute associate professor. “Whether chronic viral infection contributes to age-associated immune dysfunction is still an open question, but studies of this type provide a way to start getting answers. At this point it’s clear that both ageing and chronic viral infections leave profound and indelible marks on immunity.”

The body is normally able to clean out acute viral infections, such as the common cold. But some viruses besides just HIV and HCV can remain alive, setting up ‘host-parasite housekeeping’ in the body, without people’s awareness. Dr Furman said that, depending on geographic location, 70 to 90% of the population is infected with cytomegalovirus. In healthy people, this is harmless and problematic only for pregnant women or those with compromised immune systems. Various herpes viruses can also lead to chronic infections.

“Each of us has our own virome; it’s the collection of the viral infections you have during your lifespan,” Furman said. “You probably have been infected by 12 or 15, or even more viruses that you never knew you had. Fortunately technology now exists that allows us to profile these infections in the human population; it is helping us move these types of inquiries forward.” Dr He said this study is the first to fully incorporate the concept of systems immunology, holistically analysing the immune system with the same technological platforms across different cohorts of patients.

The study demonstrated that in patients with HIV, immune system dysregulations were evident despite having been on antiretrovirals for over ten years. However, clearing the HCV virus partially restored cellular sensitivity to interferon-a, which inhibits viral replication. “This plasticity means there is room for intervention in both chronic viral infections and in ageing,” said Dr Furman. “It’s just a matter of identifying and understanding the molecular pathways and networks involved.” The study also identified changes in STAT1, the primary transcription factor activated by interferons. STAT1 plays a major role in normal immune responses, particularly to viral, mycobacterial and fungal pathogens.

As for COVID, Dr Furman said that we are in the midst of an ongoing “living” experiment. Future studies are needed to determine whether the functional imprinting of the immune system is hardwired to only involve the chronic nature of specific infections, or whether short but vigorous ones such as COVID also leave a lasting mark on the immune system. “Has the immune system of those infected with the coronavirus taken a big hit? That’s a theory, but we don’t know what will happen,” says Furman, who is collaborating with Stanford University and the University of California, San Francisco on projects involving COVID-19 and immunity.

Source: Medical Xpress

Journal information: Cesar J. Lopez Angel et al., “Signatures of immune dysfunction in HIV and HCV infection share features with chronic inflammation in aging and persist after viral reduction or elimination,” PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2022928118

Categories : Ageing NeurologyTags :

Jump-Starting Neural Stem Cells in Aged Brains

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As we age, neural stem cells lose the ability to divide and create new neurons, resulting in a decline in memory. Now, research led by Sebastian Jessberger, a professor at the Brain Research Institute of the University of Zurich, explains why this happens.

The new neurons are used all over the brain, including the hippocampus which is responsible for memory. Declines here from age and Alzheimer’s mean fewer neurons are produced here, impacting memory functions.

“As we get older, stem cells throughout the body gradually lose their ability to proliferate. Using genetic engineering and cutting-edge microscope technology, we were able to identify a mechanism that is associated with this process,” explained doctoral candidate and first author Khadeesh bin Imtiaz. The results were published in the journal Cell Stem Cell.

The study used a mouse model to show that as organisms age, neurons’ ability to divide becomes impaired. Protein structures ensure that accumulated harmful proteins are laid out unequally among the two daughter neurons, important for the longevity of neurons. As the neurons age, the amount of nucleic proteins changes, resulting in impaired distribution of proteins, reducing the number of newly generated neurons in the brains of older mice.

The researchers identified a nuclear protein called lamin B1, levels of which decrease as people age. When lamin B1 was increased in aged mice, there was an improvement in stem cell division and the number of neurons increased.

The study was part of wider research into ageing and stem cells. “While our study was limited to brain stem cells, similar mechanisms are likely to play a key role when it comes to the ageing process of other stem cells,” said Prof Jessberger.

The latest findings represent an important step in understanding how brain stem cells change with age. “We now know that we can reactivate aging stem cells in the brain. Our hope is that these findings will one day help increase levels of neurogenesis, for example in older people or those suffering from degenerative diseases such as Alzheimer’s. Even if this may still be many years in the future,” concluded Prof Jessberger.

Source: Medical Xpress

Journal information: Cell Stem Cell, DOI: 10.1016/j.stem.2021.01.015