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Trending With Impact: Cognitive Decline Predicted from Middle-Age

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Researchers investigated epigenetic and brain aging markers in middle-age for their potential to predict cognitive decline.

Trending With Impact: Cognitive Decline Predicted from Middle-Age

The Trending With Impact series highlights Aging (Aging-US) publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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Aging seems nearly synonymous with brewing cognitive decline, but does it have to be? There are interventions that may help preserve cognitive function with age, however, the first order of business is identifying early biological aging markers that present before symptoms begin emerging. Mid-life biomarkers that can indicate accelerated aging and predict age-related cognitive decline (including Alzheimer’s disease and dementia) may provide humans with enough time to course-correct and improve our quality of life in old age.

The latest to endeavor in search of these early aging markers are researchers from Northwestern University Feinberg School of Medicine, University of Texas Health Science Center at San Antonio, University of Pennsylvania, Boston University School of Medicine, National Institute on Aging from the National Institutes of Health, University of Minnesota, Columbia University Mailman School of Public Health, Kaiser Permanente Division of Research, University of Texas at Austin, University of California San Francisco, and the San Francisco Veterans Affairs Medical Center. Their new research study was published in Aging (Aging-US) as the cover paper in Volume 14, Issue 4, on February 27, 2022. The paper is entitled, “Mid-life epigenetic age, neuroimaging brain age, and cognitive function: coronary artery risk development in young adults (CARDIA) study.”

The Study

In this study, the researchers looked at the associations between cognitive function, epigenetic age and age acceleration measures (using DNA methylation), and brain imaging data in a biracial cohort involving 1,676 healthy human participants. These participants were derived from the Coronary Artery Risk Development in Young Adults (CARDIA) study. The CARDIA study began in 1985 with the aim of tracking changes in cardiovascular disease risk factors among thousands of young-adult to middle-age participants. The average age of participants in this current study was 40 years old.

Participants were evaluated for cognitive function using three tests: the Rey Auditory Verbal Learning Test (RAVLT), Trail Making Test B-A (TMTB-A) and the Digit Symbol Coding Test (DSCT). The researchers assessed and re-analyzed the cohort twice (up to 15 years apart). Data were generated for two separate sub-studies. The first sub-study looked specifically at DNA methylation (DNAm) data using GrimAge, PhenoAge, Hannum’s DNAm Age, and Horvath’s DNAm Age. The second sub-study collected neuroimaging data from participants using magnetic resonance imaging (MRI) scans.

“While blood-derived epigenetic aging markers have shown predictive value years before age-related diseases occur [21–23], biological aging rates can differ across organ systems, so predictors derived directly from the brain may hold unique information for cognition [24, 25].”

The researchers note that aging-related brain atrophy occurs in a predictable manner across the human lifespan. Therefore, brain atrophy is the measure of brain aging identified by MRI scans in this study. To translate the atrophy of brain structures into a biomarker of aging, the team leveraged machine-learning algorithms to generate a composite age-related morphological index called the Spatial Pattern of Atrophy for Recognition (SPARE) of Brain Age (SPARE-BA).

“The goal of the present study was to quantify the associations of epigenetic age acceleration and SPARE-BA acceleration with subsequent cognitive performance in a biracial cohort (~40% Black participants and ~60% White participants) of middle-aged adults with 5 to 15 years of follow up.”

The Results

Out of the four epigenetic aging markers examined, the researchers found that GrimAA was uniquely capable of closely predicting worse cognitive outcomes in this middle-aged CARDIA population. In the long term, biomarkers of epigenetic aging were more stable predictors of cognitive decline than the brain aging biomarker. However, changes in SPARE-BA and the SPARE-BA acceleration (SPARE-BAA) index showed stronger associations with cognition over time than any of the epigenetic aging markers. The researchers believe this is because the brain age/aging biomarkers may be more temporally dynamic in association with cognitive decline. When the researchers compared each biomarker’s association with cognition, they found that a combined model of GrimAA and SPARE-BAA demonstrated an improved ability to predict lower cognitive performance.

“GrimAA and SPARE-BAA were not correlated with one another, indicating that they capture distinct facets of biological aging.”

Conclusion

The researchers were forthcoming about limitations in this study. The epigenetic and brain imaging markers were mostly derived from different participants within the study, therefore, other unmeasured factors may have contributed to the study results. Baseline cognitive data was not recorded at younger ages and epigenetic markers were collected at different time points than cognitive and neuroimaging outcomes. These differences inhibited cross-sectional analysis of epigenetic and brain aging. In addition, predictions may be better validated with extended follow-up periods. Nonetheless, this research may have identified two profoundly useful indicators of cognitive decline that could be put to use as early as middle-age—a potential “tipping point” in the human lifespan; when interventions may still prevent irreversible cognitive impairment.

“With further validation, epigenetic and brain aging markers may help aid timely identification of individuals at risk for accelerated cognitive decline and promote the development of interventions to preserve optimal functioning across the lifespan.”

Click here to read the full research paper published by Aging (Aging-US).

AGING (AGING-US) VIDEOS: YouTube | LabTube | Aging-US.com

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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Behavioral Aging Study and Ethical Lifespan Assessment of Hybrid Mice

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Researchers analyzed the behavior of hybrid mice and presented a novel method to qualitatively estimate natural lifespan.

Lifespan stopwatch
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Mice are frequently used as research models in aging studies. In 2019, researchers from the University of Gothenburg, R&D AstraZeneca, Harvard Medical School, and Karolinska Institutet identified logistical and ethical issues with the standard system of handling murine models in aging studies. Historically, researchers have favored using male mouse models instead of females, especially in pharmaceutical drug discovery and testing. However, half of the human population is female, and thus, females are half of the recipients of pharmaceuticals on the market. There is a need to fill this gap in research by emphasizing the assessment of both male and female subjects in research studies. The second logistical problem is the use of inbred mice. Inbred laboratory mice tend to have strain-specific behaviors that can skew study results. Therefore, there is a need to replace inbred mice with hybrid mice, especially in behavioral aging studies.

Lastly, the researchers addressed lifespan assessment in mice. Due to ethical concerns, many institutions do not allow researchers to study lifespan in mice. These concerns arose from researchers allowing mice to pass away naturally, even if some mice are terminally ill and suffering. In a research paper published by Aging (Aging-US) in 2019, the researchers came up with a novel method of ethically assessing lifespan. They also employed male and female F2 hybrid mice in a behavioral aging study. Their paper was entitled, “Conclusions from a behavioral aging study on male and female F2 hybrid mice on age-related behavior, buoyancy in water-based tests, and an ethical method to assess lifespan.”

Behavioral Aging Studies in Mice

“In this study, F2 hybrid female and male mice were assessed for behavioral tests with the aim to investigate sex differences and age-related alterations.”

The team used various behavioral tests in order to gain a better understanding of the behavioral effects of aging in female and male F2 hybrid mice. Behavioral tests included an open-field test in an activity box, the shuttle box passive avoidance test, physiological analyses for behavioral phenotyping at seven, 15 and 22 months of age, and a swim test to measure immobility. Immobility in the swim test was an indicator of depressive-like behavior.

In sum, the researchers demonstrated that decreased exploratory behavior is a robust behavioral marker of aging in both male and female hybrid mice. However, altered learning, memory and depressive-like behavior were not significant markers of aging in these models. To this end, the team did not find sex differences in learning or memory using the passive avoidance test. In females, fat mass accounted for 30-46% of the observed increase in depressive-like behavior compared to males.

“This novel finding emphasizes the need to control for body composition in water-based tests.”

Ethical Murine Lifespan Assessment

The ethical method of lifespan assessment the researchers devised involves using estimates of lifespan. In a separate cohort from the behavioral studies, the researchers created this lifespan estimation by separating mice with signs of pain or severe disease from the healthy aging mice. The ill animals were euthanized and then included in two separate data curves. In one curve, the euthanized animals were counted as if their time of death was from natural causes (an underestimation of their lifespan). The researchers then made a second data curve in which they calculated that the euthanized animals as if they had been as healthy as their littermates (an overestimation of their lifespan since the euthanized animals were terminally ill). These curves created an interval that was used as the minimum and maximum lifespan of this cohort. 

“We think this is a really good method that we hope people will start using in lifespan analysis,” said Malin Hernebring, from the University of Gothenburg and R&D AstraZeneca, in a recent Behind the Study interview with Aging-US. 

Conclusion

The researchers presented a novel method to estimate natural lifespan in survival studies, in which animals in pain or with severe disease are not left to suffer until the end of their natural lifespan. This new method provides a qualitative estimation of natural lifespan, without the expense of animal welfare. The study also showed that F2 hybrid mice are effective in behavioral aging studies, and that fat mass partially accounts for increased immobility in aging female mice. 

The researchers hope that their findings will lead to changes in the way aging research is conducted. In particular, they hope that more emphasis will be placed on testing both male and female subjects, that inbred mice will be replaced with hybrid mice and that their ethical method of lifespan assessment in mouse models is adopted at scale.

“In summary, this work is the first behavioral phenotypic aging study to use hybrid mice and include analyses of both sexes.”

Click here to read the full research paper published by Aging (Aging-US).

AGING (AGING-US) VIDEOS: YouTube | LabTube | Aging-US.com

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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Trending With Impact: Can Job Stress Cause Epigenetic Aging?

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The association between job-related stress and epigenetic aging was investigated using five epigenetic clocks and a Finnish cohort.

Job stress

The Trending With Impact series highlights Aging (Aging-US) publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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In aging research, recent evidence has encouraged more focus on investigating socioeconomic status (SES) and its role in human health trajectories. Previous studies have used DNA methylation measures and epigenetic clocks to demonstrate a consistent association between low SES and epigenetic age acceleration (EAA). Moreover, researchers have identified a need to further investigate the relationship between SES characteristics and aging.  

“Little is known whether current occupational characteristics or job-related stress – crucial SES characteristics – are associated with EAA.”

Recently, researchers—from Imperial College London, University of Sassari, University of Eastern Finland, Karolinska Institutet, University of Oulu, and the Italian Institute for Genomic Medicine—conducted a research study in an effort to help elucidate potential mechanisms by which work characteristics and job stressors may be impacting health and accelerating aging. Their trending research paper was published by Aging (Aging-US) on February 2, 2022, and entitled, “Work-related stress and well-being in association with epigenetic age acceleration: A Northern Finland Birth Cohort 1966 Study.” 

The Study

The researchersin this study included 604 participants from the Northern Finland Birth Cohort 1966. Participants in this cohort were all born in the provinces of Oulu and Lapland, Finland, in 1966. DNA samples were collected and used to determine the relationship between biomarkers of aging, job stress and common environmental factors associated with age acceleration, including obesity, smoking, alcoholism, education status, and physical activity. The team used five different epigenetic clocks as biomarkers of aging: HorvathAA, HannumAA, PhenoAgeAA, GrimAgeAA, and DunedinPoAm.

“In this work, we assessed the association (and its magnitude) of five biomarkers of epigenetic age acceleration with work-related stress and well-being indicators (as well as other employment characteristics) in the Northern Finland Birth Cohort 1966, at 46 years old.”

Participants also filled out a clinical examination questionnaire, a modified Karasek’s Job Content Questionnaire (to assess job strain) and the Occupational Stress Questionnaire (to measure effort-reward imbalance). A number of descriptive statistics were collected from each participant, including body mass index (BMI); educational level; alcohol consumption; smoking habits; physical/leisure activity; job status (employed/unemployed); employer type (private or state/municipality); occupational group (white-collar or blue-collar); and job exposure. The researchers defined “job exposure” as job strain, effort-reward imbalance, overcommitment, occupational physical activity, work-favoring attitude, job security and work engagement, history, hours, and shift. 

The Results

After using linear regression models to analyze the adjusted and unadjusted pooled data (males and females together), the researchers found that job strain was not significantly associated with EAA using any of the epigenetic clocks. All five clocks associated smoking and obesity with accelerated aging (at varying significance). However, alcohol use (even heavy use) was not significantly associated with accelerated aging on any of the clocks. PhenoAgeAA associated job strain, active work and white-collar work (compared to blue-collar) with decreased aging. According to the Hannum and HorvathAA biomarkers of aging, people who worked more than 40 hours per week showed increased EAA.

“Once we stratified analyses by sex, a different pattern of association emerged, with women leading on the statistically significant results.”

Next, the researchers further stratified the results by sex. In men, high-intensity physical effort at work had a decreased aging effect. However, for women, high-intensity physical effort at work had an increased aging effect. The researchers point out that these clocks may have contradictory result due to the fact that women and men often present with diverse, sex-specific epigenetic patterns. While a direct correlation between job stress and epigenetic aging have yet to be proven, the degree of association between work characteristics and biomarkers of epigenetic aging in this study did vary by sex.

Conclusion

“This paper is one of the first attempts to address the working dimension of epigenetic age acceleration indicators, to the best of our knowledge.”

The Northern Finland Birth Cohort 1966 is a useful sample for studying a general population, and many confounders were removed in doing so. However, the researchers were forthcoming about some limitations that remained in this study. The unique characteristics of the cohort, as well as the questionnaires, may be responsible for the results seen in the study. The researchers suggest that additional studies be carried out in other societies and on different types of jobs to account for gender differences. 

“Our results suggest that women and men present different associations with different epigenetic distributions regarding work-related stress indicators.”

Click here to read the full research paper published by Aging (Aging-US).

AGING (AGING-US) VIDEOS: YouTube | LabTube | Aging-US.com

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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Trending With Impact: Radiation, Senescence and Senotherapeutics

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Researchers examined the effects of thoracic radiation-induced senescent cells on tumor progression, and the role of senotherapeutics to mitigate these effects.

Radiation therapy, advanced medical linear accelerator in therapeutic oncology to treat cancer
Radiation therapy, advanced medical linear accelerator in therapeutic oncology to treat cancer

The Trending With Impact series highlights Aging (Aging-US) publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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Radiation therapy is a highly-efficacious inducer of cancer cell death. With this being said, radiation has also previously been shown to cause premature senescence in the lung parenchyma. Senescence in cancer cells was previously only thought of as a mechanism capable of suppressing tumor cell proliferation by halting the cell cycle. However, a growing body of evidence shows that senescent cells may play a pro-tumorigenic role in cancer.

In the tumor microenvironment, the accumulation of senescent cells can become tumorigenic due to a lack of normal tissue stem cells and due to the expression of the senescence-associated secretory phenotype (SASP). SASP expression is when senescent cells secrete high levels of inflammatory cytokines, immune modulators, growth factors, and proteases. In addition to reinforcing senescence, SASP can create a biological environment that is immuno-suppressed and tumor-permissive. Radiation-induced senescence has previously been shown to have negative impacts on cancer patients.

“Cells that have undergone premature senescence due to stress, such as irradiation, are resistant to apoptotic cell death and effectively escape immune surveillance, resulting in their accumulation in tissue over time.”

Recently, researchers from the National Cancer Institute investigated the irradiated lung and the impact of radiation-induced senescent parenchymal cells on tumor growth. They also explored three senotherapeutics, rapamycin, INK-128 and ABT-737, for their potential to mitigate radiation-induced senescence. On February 12, 2022, the team’s priority research paper was published on the cover of Aging (Aging-US) Volume 14, Issue 3, and entitled, “Senescence-associated tumor growth is promoted by 12-Lipoxygenase.”

The Study

In this study, researchers intravenously injected melanoma cells into murine models two, four and eight weeks after daily fractions of thoracic irradiation exposure. There was also a control arm of unirradiated murine models. Tumor development was monitored by the number and size of the nodules in lung tissues. The number of cells exhibiting senescent activity was also recorded after two, four and eight weeks of thoracic irradiation. Their data demonstrated a correlation between the time points when tumors developed in the irradiated lungs and a marked accumulation of senescent cells.

“As previously described, in irradiated lungs, senescent cells increased significantly 4 and 8 weeks after IR compared to age matched unirradiated controls (Figure 1A).”

A characteristic of oncogene- and stress-induced senescence is the activation of mTOR signaling. Given this connection, the researchers conducted parallel studies evaluating senostatic agents capable of targeting the mTOR pathway, rapamycin and INK-128, and a senolytic agent to selectively eliminate senescent cells, ABT-737.  The data showed that rapamycin and INK-128 significantly reduced the number of tumor nodules in the lungs of irradiated mice compared to the controls. ABT-737 demonstrated reduced pulmonary senescence in irradiated mice.

The researchers also studied 12-Lipoxygensae (12-LOX), an enzyme that metabolizes a certain SASP molecule previously implicated in pulmonary senescence: 12(S)-HETE. 12-LOX is a known contributor to radiation-induced senescence and lung injury. The team specifically focused on the role of 12-LOX in pulmonary senescence and its impact on radiation-enhanced tumor growth. They found that inhibiting 12-LOX activity reduced radiation-induced lung senescence and mitigated radiation-enhanced tumor growth.

“Finally, we link senescence associated 12-LOX activity and production of 12(S)-HETE to the observed enhanced tumor growth after irradiation.”

Conclusion

In sum, the researchers found that radiation therapy can induce senescence in the lung parenchyma and also enhance tumor growth. The contribution of senescence in tumor progression was emphasized by the protection delivered by the mTOR-targeted senostatic and senolytic agents. This important discovery could lead to new therapies for cancer patients who are undergoing radiation therapy.

“Together, this study demonstrates the critical role of senescence in mediating radiation-enhanced tumor growth and identifies Alox12 as an important player in this phenomenon. Treatment with a senostatic agent, INK-128, identified in this study, or with agents like rapamycin and ABT-737 suggested their potential therapeutic use in alleviating radiation associated tumor growth.”

Click here to read the full priority research paper published by Aging (Aging-US).

AGING (AGING-US) VIDEOS: YouTube | LabTube | Aging-US.com

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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Trending With Impact: ARDD21 Meeting Report Highlights

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Read a brief summary of a meeting report from the 8th Annual Aging Research and Drug Discovery (ARDD21) meeting. 

ARDD21

The Trending With Impact series highlights Aging (Aging-US) publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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The 8th Annual Aging Research and Drug Discovery (ARDD21) meeting was held in Copenhagen, Denmark, from August 30 to September 3, 2021. This meeting was attended by over 130 people on-site, with an additional 1800 people engaged online. The focus of this meeting was the current landscape of aging research and various ways it can be applied to drug discovery. Topics included: age-dependent control of cellular maintenance processes, longevity pathways, artificial intelligence-based drug screening, cellular stress and aging, the benefits of dietary restriction, stem cell rejuvenation, senolytics as an aging therapeutic, diverse models of aging, aging clocks and biomarkers of aging, new ideas in preclinical and clinical aging research, the longevity industry landscape, and a Longevity Medicine Workshop.

In total, there were 75 presentations given at ARDD21 by prominent and dedicated aging researchers. The meeting was thoroughly summarized in a paper published in Aging (Aging-US) Volume 14, Issue 2, entitled, “Meeting Report: Aging Research and Drug Discovery.”

ARDD21 Meeting Report Highlights

One of the keynote presentations was given by Nir Barzilai from the Albert Einstein College of Medicine. He discussed his work on aging and how it can be applied to drug discovery. One interesting finding that he discussed was that many drugs currently used to treat chronic diseases, such as diabetes and heart disease, also have the potential to treat aging. This is due to the fact that many diseases are symptoms of aging, and thus, treating the underlying cause (aging) can in turn treat the symptoms.

Another keynote presentation was given by James Kirkland from the Mayo Clinic. He discussed his work on developing therapies to target senescent cells. Senescent cells can accumulate with age, and their presence has been linked with a variety of age-related conditions such as arthritis, cancer and heart disease. Kirkland’s team has developed a number of potential therapies to eliminate or reduce the number of senescent cells in the body, and he is currently testing them in clinical trials.

Professor Dame Linda Partridge from Max Planck Institute for Biology of Ageing presented on aging and the importance of intestinal homeostasis. Her studies involved rapamycin treatment to act on the longevity pathway mTOR, which revealed that short term and early treatment with rapamycin extends lifespan in D. melanogaster as much as chronic rapamycin treatment. Yu-Xuan Lu, another researcher from the Max Planck Institute for Biology of Ageing, demonstrated the existence of an unconventional intestine sex-specific TORC1-histone axis which uncovers a new aspect of improved longevity with rapamycin.

Brian Kennedy from the Buck Institute for Research on Aging, National University of Singapore and National University Health System showed how Alzheimer’s disease can be used as a model of neuronal aging. Presenting their new WormBot, Matt Kaeberlein from the University of Washington described a “set it and forget it” method of large-scale intervention testing in roundworms (C. elegans). 

“He stressed the importance of broad and unbiased screening of intervention beyond known pathways and in different combinations [56].”

Aging (Aging-US) Editorial Board member Alexey Moskalev from the Russian Academy of Sciences presented on the disruption of hydrogen sulfide homeostasis and its association with aging, and therefore, its potential as a gero-therapeutic target. David Sinclair from Harvard Medical School (also on the Aging Editorial Board) discussed aging-driven epigenetic and gene expression changes in the central nervous system. He showed that this can be safely reversed to restore vision by inducible adeno-associated viruses expressing polycistronic Oct4, Sox2 and Kif4, and that the effect is dependent on DNA demethylation. Finally, a Longevity Medicine Workshop was held with a panel of experts aimed to inspire young students to engage in longevity research. This panel included Aging Editorial Board members Alex Zhavoronkov, Alexey Moskalev and Mikhail Blagosklonny (Editor-In-Chief).

Conclusion

Overall, the ARDD21 meeting was a fruitful exhibition of experts from all areas of aging research that came together to share their latest findings in the field. The highlights in this blog pale in comparison to the thoughtful details included in the original meeting report. 

Click here to read the full meeting report published by Aging (Aging-US).

AGING (AGING-US) VIDEOS: YouTube | LabTube | Aging-US.com

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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How Habitual Tea Drinking Impacts Brain Structure

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In 2019, researchers conducted the first study to explore the effects of habitual tea drinking on system-level brain networks.

Figure 3. Brain regions exhibiting significant differences in structural nodal efficiency between the tea drinking group and the non-tea drinking group at the significance level of 0.01 (uncorrected) statistical evaluated by a permutation test.
Figure 3. Brain regions exhibiting significant differences in structural nodal efficiency between the tea drinking group and the non-tea drinking group at the significance level of 0.01 (uncorrected) statistical evaluated by a permutation test.
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After water, tea is the most popular beverage in the world. While many people enjoy tea for the flavor, aroma and caffeine boost, research suggests that there may be another reason to regularly drink this beverage: its effects on the brain. In 2019, researchers from Wuyi University, University of Essex, University of Cambridge, and the National University of Singapore conducted the first study exploring the effects of tea on system-level brain networks. Their paper was published in Aging (Aging-US) Volume 11, Issue 11, and entitled, “Habitual tea drinking modulates brain efficiency: evidence from brain connectivity evaluation.”

“In this study, we comprehensively explored brain connectivity with both global and regional metrics derived from structural and functional imaging to unveil putative differential connectivity organizations between tea drinking group and non-tea drinking group.”

The Study

The subjects enrolled in this study were older adults (mean ≈ 70 years old) from residential communities in Singapore, without conditions or terminal illnesses (see Materials and Methods). Researchers initially recruited 93 participants, however, only 36 total participants (male = 6; female = 30) remained after adjusting for the strict study inclusion criteria. Researchers classified the remaining participants as “non-tea drinkers” or “tea drinkers” using complex composite test scores. The composite score included self-reports of multiple decades of weekly green tea, oolong tea, black tea, and coffee intake (see Materials and Methods). After screening, 15 participants were assigned to the tea-drinking group and 21 were assigned to the non-tea drinking group. (Coffee intake did not differ significantly between the two groups.)

Next, structural brain connectivity was compared between tea drinkers and non-tea drinkers. All 36 participants underwent MRI brain scans and both functional and structural networks were investigated from global and regional perspectives. The researchers found that participants in the tea-drinking group had more efficient structural organization. However, tea did not seem to have a significantly beneficial effect on global functional organization. As a result of tea drinking, hemispheric asymmetry in the structural connectivity network was observed, although it was not observed in the functional connectivity network. 

“In addition, functional connectivity strength within the default mode network (DMN) was greater for the tea-drinking group, and coexistence of increasing and decreasing connective strengths was observed in the structural connectivity of the DMN.”

Conclusion

The researchers found that tea drinkers had more efficient brain structure organization than non-tea drinkers. Studies have previously demonstrated that tea drinkers are less likely to develop dementia, and tea consumption has also been linked with better cognitive performance. The researchers note that these effects are due to tea’s contents of caffeine, L-theanine and polyphenols (catechins). Polyphenols are compounds found in plants, including tea leaves, and may help protect against oxidative damage. Previous studies have shown that tea polyphenols can cross the blood-brain barrier and may help improve brain function. 

While this study’s findings suggest that habitual tea drinking leads to better brain connectivity and efficiency in old age, the researchers were forthcoming about the limitations of their study. The sample size was limited and other substances, behaviors, habits, and environmental factors may have impacted the outcome of the study. 

“Our study offers the first evidence of the positive contribution of tea drinking to brain structure and suggests a protective effect on age-related decline in brain organisation.”

Click here to read the full research paper published by Aging (Aging-US).

AGING (AGING-US) VIDEOS: YouTube | LabTube | Aging-US.com

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Aging (Aging-US) is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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Aging’s Top 10 Most-Viewed Papers in 2021

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Aging's Top 10 papers of 2021

Read the 10 most-viewed papers on Aging-US.com of 2021.

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#10: Iron: an underrated factor in aging

Author: Dennis Mangan

Institution: MTOR LLC

Quote: “Blocking iron absorption through drugs or natural products extends lifespan. Many life-extending interventions, such as rapamycin, calorie restriction, and old plasma dilution can be explained by the effects they have on iron absorption, excretion, and metabolism.”

#9: Reversal of cognitive decline: A novel therapeutic program

Author: Dale E. Bredesen

Institutions: University of California Los Angeles and Buck Institute for Research on Aging

Quote: “This report describes a novel, comprehensive, and personalized therapeutic program that is based on the underlying pathogenesis of Alzheimer’s disease, and which involves multiple modalities designed to achieve metabolic enhancement for neurodegeneration (MEND).”

#8: Shorter telomere lengths in patients with severe COVID-19 disease

Authors: Raul Sanchez-Vazquez, Ana Guío-Carrión, Antonio Zapatero-Gaviria, Paula Martínez, and Maria A. Blasco

Institutions: Spanish National Cancer Research Center – CNIO and Field Hospital COVID-19, IFEMA

Quote: “The incidence of severe manifestations of COVID-19 increases with age with older patients showing the highest mortality, suggesting that molecular pathways underlying aging contribute to the severity of COVID-19. One mechanism of aging is the progressive shortening of telomeres, which are protective structures at chromosome ends.”

#7: Hyperbaric oxygen therapy alleviates vascular dysfunction and amyloid burden in an Alzheimer’s disease mouse model and in elderly patients

Authors: Ronit Shapira, Amos Gdalyahu, Irit Gottfried, Efrat Sasson, Amir Hadanny, Shai Efrati, Pablo Blinder, and Uri Ashery 

Institutions: Tel Aviv University and Assaf Harofeh Medical Center

Quote: “Hyperbaric oxygen therapy (HBOT) is in clinical use for a wide range of medical conditions. In the current study, we exposed 5XFAD mice, a well-studied AD model that presents impaired cognitive abilities, to HBOT and then investigated the therapeutical effects using two-photon live animal imaging, behavioral tasks, and biochemical and histological analysis.”

#6: Fighting the storm: could novel anti-TNFα and anti-IL-6 C. sativa cultivars tame cytokine storm in COVID-19?

Authors: Anna Kovalchuk, Bo Wang, Dongping Li, Rocio Rodriguez-Juarez, Slava Ilnytskyy, Igor Kovalchuk, and Olga Kovalchuk

Institutions: Pathway Research Inc., University of Calgary and University of Lethbridge

Quote: “Cannabis sativa has been proposed to modulate gene expression and inflammation and is under investigation for several potential therapeutic applications against autoinflammatory diseases and cancer. Here, we hypothesized that the extracts of novel C. sativa cultivars may be used to downregulate the expression of pro-inflammatory cytokines and pathways involved in inflammation and fibrosis.”

#5: Examining sleep deficiency and disturbance and their risk for incident dementia and all-cause mortality in older adults across 5 years in the United States

Authors: Rebecca Robbins, Stuart F. Quan, Matthew D. Weaver, Gregory Bormes, Laura K. Barger, and Charles A. Czeisler

Institutions: Brigham and Women’s Hospital, Harvard Medical School and Boston College

Quote: “Sleep disturbance and deficiency are common among older adults and have been linked with dementia and all-cause mortality. Using nationally representative data, we examine the relationship between sleep disturbance and deficiency and their risk for incident dementia and all-cause mortality among older adults.”

#4: Rejuvant®, a potential life-extending compound formulation with alpha-ketoglutarate and vitamins, conferred an average 8 year reduction in biological aging, after an average of 7 months of use, in the TruAge DNA methylation test

Authors: Oleksandr Demidenko, Diogo Barardo, Valery Budovskii, Robb Finnemore, Francis R. Palmer III, Brian K. Kennedy, and Yelena V. Budovskaya

Institutions: TruMe Inc., National University Singapore, Ponce de Leon Health, National University Health System Singapore, and Singapore Institute for Clinical Sciences, A*STAR

Quote: “Instead, aging biomarkers, such as DNA methylation (DNAm) clocks, have been developed to monitor biological age. Herein we report a retrospective analysis of DNA methylation age in 42 individuals taking Rejuvant®, an alpha-ketoglutarate based formulation, for an average period of 7 months.”

#3: Aging and rejuvenation – a modular epigenome model

Authors: Priscila Chiavellini, Martina Canatelli-Mallat, Marianne Lehmann, Maria D. Gallardo, Claudia B. Herenu, Jose L. Cordeiro, James Clement, and Rodolfo G. Goya

Institutions: National University of La Plata, National University of Cordoba, World Academy of Art and Science (WAAS), and Betterhumans Inc.

Quote: “The view of aging has evolved in parallel with the advances in biomedical sciences. Long considered as an irreversible process where interventions were only aimed at slowing down its progression, breakthrough discoveries like animal cloning and cell reprogramming have deeply changed our understanding of postnatal development, giving rise to the emerging view that the epigenome is the driver of aging.”

#2: Potential reversal of epigenetic age using a diet and lifestyle intervention: a pilot randomized clinical trial

Authors: Kara N. Fitzgerald, Romilly Hodges, Douglas Hanes, Emily Stack, David Cheishvili, Moshe Szyf, Janine Henkel, Melissa W. Twedt, Despina Giannopoulou, Josette Herdell, Sally Logan, and Ryan Bradley

Institutions: Institute for Functional Medicine, American Nutrition Association, National University of Natural Medicine, Ariel University, McGill University, and University of California San Diego

Quote: “Manipulations to slow biological aging and extend healthspan are of interest given the societal and healthcare costs of our aging population. Herein we report on a randomized controlled clinical trial conducted among 43 healthy adult males between the ages of 50-72.”

#1: Hyperbaric oxygen therapy increases telomere length and decreases immunosenescence in isolated blood cells: a prospective trial

Authors: Yafit Hachmo, Amir Hadanny, Ramzia Abu Hamed, Malka Daniel-Kotovsky, Merav Catalogna, Gregory Fishlev, Erez Lang, Nir Polak, Keren Doenyas, Mony Friedman, Yonatan Zemel, Yair Bechor, and Shai Efrati

Institutions: Shamir Medical Center, Tel Aviv University and Bar Ilan University

Quote: “At the cellular level, two key hallmarks of the aging process include telomere length (TL) shortening and cellular senescence. Repeated intermittent hyperoxic exposures, using certain hyperbaric oxygen therapy (HBOT) protocols, can induce regenerative effects which normally occur during hypoxia. The aim of the current study was to evaluate whether HBOT affects TL and senescent cell concentrations in a normal, non-pathological, aging adult population.”

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

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Trending With Impact: Are Our Muscles Intrinsically Impaired by Aging?

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In a priority research paper published by Aging-US in January of 2022, researchers investigated aged muscle stem cells and their ability to sense and respond to mechanical cues.

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3D Illustration of muscle tissue
3D Illustration of muscle tissue

The Trending With Impact series highlights Aging (Aging-US) publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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IIs muscle wasting a fate humans can avoid, or will the problem of aging-related muscle loss only be resolved when the mystery of aging is solved? Researchers—from Vrije Universiteit Amsterdam, University of Amsterdam, Sorbonne Université, Amsterdam University Medical Center VUmc, Université Catholique de Louvain, KU Leuven, and Institut NeuroMyoGène—conducted a study aimed at elucidating whether muscle stem cells are inherently impaired by the aging process in their ability to sense and respond to mechanical cues. Their priority research paper was published in January of 2022 on the cover of Aging (Aging-US) Volume 14, Issue 1, and entitled, “Reduced growth rate of aged muscle stem cells is associated with impaired mechanosensitivity.”

Muscle Stem Cells

Muscle stem cells (MuSCs) are stem cells located within skeletal muscle tissues. MuSCs function to repair Muscle stem cells (MuSCs) are stem cells located within skeletal muscle tissues. MuSCs function to repair damaged myofibers and give rise to new skeletal muscle cells. These self-renewing stem cells are involved in muscle growth, repair and regeneration. As we age, MuSCs decline in number and lose their potential to regenerate damaged myofibers, leading to sarcopenia. The researchers in this study hypothesized that the responsiveness of aged MuSCs is impared by the aging process both physically and mechanically.

“We postulated that aged MuSCs are intrinsically impaired in their responsiveness to omnipresent mechanical cues through alterations in MuSC morphology, mechanical properties, and number of integrins, culminating in impaired proliferative capacity.”

The Study

The researchers assessed whether aged MuSCs become impaired in their ability to proliferate, respond to pulsating fluid shear stress (PFSS) mechanical loading, maintain focal adhesion number and/or size after mechanical loading, and in their ability to express the protein-coding gene Integrin Subunit Alpha 7 (ITGA7). 

“Integrins are transmembrane protein receptors that connect MuSCs to the ECM [extracellular matrix] components and are part of focal adhesions [51].”

Young MuSCs (2 months) and aged MuSCs (22 months) were isolated from male mice. Fluorescence-activated cell purification was carried out and cells were cultured. To measure proliferation, images were captured of the cell cultures every 24 hours. Images were also taken pre- and post-PFSS to determine the number of young and aged MuSCs detached from the culture media (focal adhesion) as a result of PFSS treatment. Since nitric oxide (NO) is known to play a role in MuSC activation and muscle regeneration, NO analysis was conducted to measure NO production. To determine MuSC morphology, the researchers carried out immunohistochemistry staining. They also measured MuSC stiffness, deformation, gene expression, and RNA isolation and reverse transcription.

Compared to young MuSCs, the researchers found aged MuSCs had impaired growth. Their results showed that IL-6 gene expression was lower in aged MuSCs, which suggested that aged MuSCs were intrinsically altered in the signaling pathways governing proliferation and MuSC function. Aged MuSCs showed an increase in cell volume and reduced cell adhesion after mechanical loading. NO levels in young and aged MuSCs were similar, and PFSS in both cultures resulted in similar increases in NO production. The researchers found decreased ITGA7 expression and reduced pPXN clusters (focal adhesion formation) were involved in altered MuSC function with age. High YAP nuclear localization was found in aged MuSCs, as well as reduced mechanosensitivity.

“Aged MuSCs were less sensitive to shear forces and showed upregulation of less genes, suggesting that the decreased mechanosensitivity was due to decreased integrin protein expression, i.e. ITGA7, ITGA5, and ITGB5, and focal adhesion number.”

Conclusion

The results from this study found that aged MuSCs were intrinsically impaired in their growth rate due to decreased ITGA7 expression and diminished focal adhesion formation. These changes coincided with increased cell volume, decreased MuSC adhesion, altered mechanosensitivity, changed YAP signaling and decreased expression of several genes (including cell cycle genes). The researchers suggest that ITGA7 and pPXN may be potential therapeutic targets to improve aged MuSC function.

“As an implication, a possible therapeutic option could be restoration ITGA7 and focal adhesion number in aged MuSCs, which may help to restore MuSCs adhesion to their niche as well as growth rate of these cells.”

Click here to read the full priority research paper published by Aging (Aging-US).

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

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Common Age-Related Changes in Eye Lenses

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In this 2019 study, researchers examined murine models to determine common age-related eye lens changes that contribute to eventual vision impairment and loss.

(Truncated) Figure 7. Whole lens staining for F-actin (phalloidin, green) and nuclei (DAPI, red) in 4-month-old and 18-month-old lenses.
Figure 7. Whole lens staining for F-actin (phalloidin, green) and nuclei (DAPI, red) in 4-month-old and 18-month-old lenses.(Truncated)
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A variety of eye disorders can occur as humans age, including age-related macular degeneration, cataracts, presbyopia, glaucoma, dry eyes, and temporal arteritis. These conditions can contribute to vision impairment and even vision loss. Unfortunately, the full gambit of common age-related eye lens changes which contribute to these disorders is not yet fully defined. However, while mice and primates are different species, their eye lenses share common characteristics. This means that studies in murine models regarding age-related eye lens changes may provide a baseline for aging studies on human eye lenses in the future. 

“Little is known about the morphological, mechanical, refractive and cellular changes that occur with advanced age in the lens. Mice offer an opportunity to investigate changes in lens morphometrics, stiffness, transparency and refractive properties with age in a relatively shortened period of time.”

To further define common age-related changes in eye lenses, researchers—from The Scripps Research Institute, University of Delaware, Morehouse School of Medicine, Nottingham Trent University, Japan Synchrotron Radiation Research Institute, and Boston University School of Medicine—conducted an extensive study of eye lenses among mice between one and 30 months of age. Their paper was published by Aging (Aging-US) in 2019, and entitled, “Age-related changes in eye lens biomechanics, morphology, refractive index and transparency.”

The Study

In this study, the researchers measured the size, refractive index (Gradient Refractive Index, GRIN) and stiffness of mouse lenses in young adult mice, starting at one and two months old, to very old mice of 24 to 30 months old. The team examined mechanisms of age-related cataracts, cell morphology in aged lenses, increased lens stiffness with age, and lens resilience. Methods used in this study include: lens biomechanical testing and morphometrics, live lens imaging, capsule thickness and fiber cell width measurements, phalloidin-staining of epithelial cells in whole lenses, scanning electron microscopy, transmission electron microscopy, and X-ray talbot interferometry. 

The researchers found that, with age, mouse eye lenses increased in size, nuclear fraction, stiffness, and resilience. After four months of age, lens capsule thickness and fiber cell width did not increase, but epithelial cell area increased slightly with age. In the lenses of mice older than 12 months, the researchers observed anterior cataracts, cortical haziness and ring cataracts. They found that the anterior cataracts were due to incomplete suture closure and detachment of anterior epithelial cells from the underlying fiber cells. The ring cataracts were linked to abnormal compaction of differentiating fiber cells. The hexagonal packing of fiber cells was shown to be disrupted with age. Lastly, the researchers observed that the gradient refractive index increased and then plateaued with age.

“Our comprehensive study of aging in wild-type mouse lenses in the B6 genetic background showed increased stiffness along with appearance of anterior, cortical and ring cataracts with age (Figure 14).”

Conclusion

Overall, the researchers demonstrate that age-related changes in mouse lenses mimic some aspects of aging in human lenses. Aside from the obvious study limitations (mouse-to-human translation), the data collected from this study provide a comprehensive overview of age-related changes in murine lenses, including lens size, stiffness, nuclear fraction, refractive index, transparency, capsule thickness, and cell structure.

“Whether there is a common molecular mechanism that drives changes in all the measured parameters remains unknown, but further biochemical and cell morphology studies will be needed to determine how subcellular aging affects the whole tissue.”

Click here to read the full research paper published by Aging (Aging-US).

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

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Aging and Circadian Rhythm: Does a Conserved Link Exist?

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In the Aging (Aging-US) Volume 13, Issue 24, cover paper, researchers conducted a study suggesting that the circadian rhythm is subjected to aging-related gene alterations.

Figure 6. Matching of our CR-related DEGs evidenced to be regulated with aging with a curated human CR network.
Figure 6. Matching of our CR-related DEGs evidenced to be regulated with aging with a curated human CR network.
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Chronobiology is the study of biological rhythms. The human circadian system is a biological process known to regulate the sleeping and waking cycle (circadian rhythm; CR). Components of the circadian system are known as ​​clock genes. Clock genes generate daily oscillations of gene expression and interact as an intricate network to influence biological processes in organisms, tissues and cells. This system is primarily regulated by Earth’s day and night cycles (light and darkness), though it can be affected by other factors, including nutrition, cellular devices, stress, illness, jet lag, and aging.

“It is well established that aging interferes with the regulation of the circadian system, which, in return, contributes to the manifestation and progression of aging-related diseases (reviewed in [4, 5]).”

Across an organism’s lifespan, changes in circadian rhythm take place. These changes can cause aging-related diseases to become more prevalent. Studies have also shown that age-independent alterations to the circadian system can result in premature aging. This interrelation between aging and CR means that aging may play a role in the circadian system and that the circadian system may play a role in aging. However, researchers have not yet fully illuminated the impact of aging-related circadian system changes on healthy organs and tissues. 

“Whether aging-related changes of the circadian system’s regulation follow a conserved pattern across different species and tissues, hence representing a common driving force of aging, is unclear.”

The Study

In an effort to identify circadian rhythm regulatory patterns over the course of aging, researchers—from Friedrich Schiller University Jena, FLI Leibniz Institute for Age Research, Jena University Hospital, German Center for Integrative Biodiversity Research, and European Virus Bioinformatics Center—performed inter-species and inter-organ transcriptional analyses. The research paper was published in December of 2021 as the cover of Aging (Aging-US) Volume 12, Issue 24, and entitled, “Age-dependent expression changes of circadian system-related genes reveal a potentially conserved link to aging.”

“Here, we used RNA-Seq data to profile the regulation of CR-related genes of 4 different species in a cross-sectional study in individuals ranging from young mature to old-age categories.”

In this cross-sectional study, the researchers used data from 329 RNA sequencing libraries to identify differentially expressed genes in transcriptional profiles among humans, house mice, zebrafish, and the extremely short-lived turquoise killifish. All human donors were classified into the following age groups of 14 to 15 individuals: mature (24–29 years), aged (60–65 years), and old-age (75–79 years). The other species were categorized into their respective age groups. Organs, including the brain, blood, liver, and skin, were examined and then compared between the four species.

The researchers found that two circadian rhythm-related genes (dec2 and per2) were altered in all four species, primarily in early- and late-aging groups. Four genes (cirp, klf10, nfil3, and dbp) with aging-related expression patterns were found in several organs and species. In total, the researchers identified six genes (in several tissues from at least three out of the four species) that function at all regulation levels of circadian rhythm with apparently conserved age-associated regulation.

Conclusion

“​​Thus, these genes might represent a conserved link between the circadian system and aging.”

This study confirms work from previous studies and extends them by providing a new dataset linking circadian rhythm factors to physiological aging across four evolutionarily distinct species. Whether circadian rhythm regulation is the cause or a consequence of the aging process still remains to be explored. The researchers note that their non-synchronized cross-sectional approach should be replicated in the future and include an additional dataset based on a longitudinal study design, tissue synchronizations across species of interest and to potentially analyze anatomic sub-regions of the brain.

“In summary, our results show that modulations in CR-related gene transcription throughout aging are a conserved trait that is traceable across evolutionarily diverse species, ranging from humans to mice and fish.”

Click here to read the full research paper published by Aging (Aging-US).

AGING (AGING-US) VIDEOS: YouTube | LabTube | Aging-US.com

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Aging (Aging-US) is an open-access journal that publishes research papers bi-monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact [email protected].

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