Common Age-Related Changes in Eye Lenses

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, glaucomadry 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 InstituteUniversity of DelawareMorehouse School of MedicineNottingham Trent UniversityJapan 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?

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 [45]).”

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 JenaFLI Leibniz Institute for Age ResearchJena University HospitalGerman 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).

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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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Investigating a Biomarker of Age-Related Macular Degeneration

Age-related macular degeneration
Ocular drusen in age-related macular degeneration (AMD).

Over 15 million people in the United States are currently struggling with age-related macular degeneration (AMD). Among aging populations around the world, AMD is the leading cause of irreversible vision loss. A main target of AMD is the pigmented layer of the retina, or the retinal pigment epithelium (RPE). The subretinal space of the eye encompasses the area under the retina between RPE cells and photoreceptors. Yellow deposits of lipids and proteins, called drusen, are located in the subretinal space and the hallmark sign of AMD. In 2005, researchers found that drusen deposits also contain an immune protein called the C-reactive protein (CRP).

Circulating CRP is one of the main clinical biomarkers of inflammation and infection, since CRP levels rise and fall with inflammation. This immune-response protein can exert pro-inflammatory properties by disassociating from its pentameric form (pCRP) into smaller monomeric CRP (mCRP) subunits. These mCRPs are small enough to cross the ocular blood–retinal barrier (oBRB) and appear in ocular drusen.

“mCRP has been identified in ocular drusen and other subepithelial deposits [2425], as well as in the choroid, and we have shown that mCRP, but not pCRP, contributes to oBRB disruption in vitro [26].”

Researchers—from Hospital Clínic de BarcelonaManchester Metropolitan UniversityHospital de la Santa Creu i Sant PauInstitute Salud Carlos IIIUniversity of BristolMoorfields Eye Hospital, and University College London Institute of Ophthalmology—conducted a study aimed at understanding the mCRP’s contribution to the pathophysiology of AMD. Their paper was published by Aging (Aging-US) in 2020, and entitled, “Activation of C-reactive protein proinflammatory phenotype in the blood retinal barrier in vitro: implications for age-related macular degeneration”.

The Study

“If mCRP pro-inflammatory capacity is unrestrained in AMD and particularly in high risk patients, then we need to determine how mCRP is generated or accumulates in the subretinal space as there is no CRP transcription in the retinal tissue [3031].”

In order to investigate how mCRP is generated and/or how it accumulates within the subretinal space, the researchers used a Transwell model to first determine whether circulating CRP could reach the subretinal space. The Transwell model included monolayers of primary porcine choroidal endothelial cells (CECs) grown on porous filters with their apical and basolateral surfaces exposed to separate chambers. They found that CRP isoforms were able to cross the CEC monolayer on the apical side of the RPE. Next, they used the Transwell model to evaluate whether CRP isoforms could also reach the subretinal space and cross RPE ARPE-19 cells. They found that mCRP was able to diffuse into both the subretinal space and cross into the RPE. pCRP was not found in the opposite chambers, even after 24 and 48 hours post-exposure. However, when the researchers tested younger and healthier primary porcine RPE cells instead of the ARPE-19 cells, neither pCRP nor mCRP diffused into opposite chambers.

Next, the researchers studied whether pCRP could dissociate into mCRP within the RPE. They found that induced inflammation triggered pCRP dissociation into mCRP in both the ARPE-19 and primary porcine RPE cells. The team also found that barrier disruption induced by mCRP was dependent on its topological localization.

Conclusion

“In summary, our findings further support mCRP direct contribution to progression of AMD, at least at the RPE level. The topological experiments elicit that mCRP is proinflammatory when present on the apical side of the RPE. However, mCRP is likely to only reach the apical side of the RPE in compromised RPE health and where barrier functions are compromised.”

The researchers were forthcoming about limitations in their study. Nonetheless, this study suggests that a plausible mechanism by which mCRP may contribute to RPE dysfunction and AMD progression is, when pCRP reaches the oBRB, it diffuses past the oBRB by dissociating into mCRP. It is also possible that mCRP may be derived from the dissociation of pCRP on the surface of damaged RPE. The proinflammatory microenvironment may be amplified and the barrier disruption may be enhanced when mCRP reaches the apical side of an already aged or damaged RPE.

“With respect to previous findings, this pathologic mechanism will be more prevalent in patients carrying the FH risk polymorphism for AMD, where mCRP proinflammatory effects remain unrestrained [28].”

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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Trending With Impact: Hair Follicles May Replace Traditional Biopsies

A new device has been developed by researchers to efficiently and painlessly collect hair follicle tissue samples from laboratory mammals, and even humans.

Figure 6. Markers of senescence analysis in hair follicular cells.
Figure 6. Markers of senescence analysis in hair follicular cells.

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.

Laboratory mammals have impacted human-kind far beyond enhancing scientific knowledge in behavioral and environmental research. These animals have greatly contributed to human healthspan and lifespan in countless ways; from validating life-saving cancer therapies to accelerating the future of human anti-aging and longevity interventions. With respect for these salubrious animals, ethical standards (per country) require that researchers handle laboratory mammals with care, and that pain and stress are minimized. Blood and skin tissue samples (biopsies) collected from animals should be replaced whenever possible. For the researchers, this twofold invasive procedure for the animals is also time- and resource-limiting—presenting a bottleneck in the biomedical research process.

“However, we present here a simple method for obtaining biological material in the form of follicular cells from laboratory mice with sufficient quantities and quality for multiple analyses using standard modern molecular biology methods.”

In an effort to efficiently and humanely solve this ethics/logistics problem, researchers—from Palacky UniversityUniversity Hospital OlomoucDanish Cancer Society Research Center, and Karolinska Institute—developed a novel, non-invasive device that can be used to collect tissue samples from hair follicles. They tested the applications of this device and authored a research paper of the study. In December of 2021, their paper was published on the cover of Aging (Aging-US) Volume 13, Issue 23, and entitled, “An efficient, non-invasive approach for in-vivo sampling of hair follicles: design and applications in monitoring DNA damage and aging.”

“As millions of laboratory mice are routinely genotyped globally every year this approach represents a major ethical and logistic breakthrough.”

The Follicular Cells’ Collector

As opposed to traditional biopsies, hair follicle collection is a humane, easy, non-invasive, and painless method of DNA and tissue sample collection. Each hair follicle contains approximately 50 cells—of various cell types. 

“This micro-organ structure also has other advantages in biomarker studies, including suitability for investigations of circadian rhythms [57], and the presence of numerous cell types in a small area, which can be easily distinguished, such as keratinocytes, melanocytes, or perifollicular macrophages and mast cells [810].”

Previously, the limitations of using hair follicles as DNA and tissue samples stemmed from ineffective technology. Many devices involved ordinary tweezers and forceps with high risks for cross-contamination. The researchers termed their novel tissue sample collection device the “follicular cells’ collector.” The follicular cells’ collector is designed with dual pipettes and utilizes a precision vacuum method of hair follicle extraction. The device can be used to comfortably collect DNA and tissue samples from laboratory mammals, and even from humans. 

“Although hair samples have been previously used for that purpose [2931], our sample collection approach may motivate researchers to use them more routinely and widely.”

The Study

To validate that these hair follicle samples contain the required genetic information necessary in most studies, researchers compared murine genotyping results of 151 tail biopsies and 151 hair samples. In order to determine the ability of these samples to detect changes in expression patterns induced by external factors, the team also observed the DNA damage response in hair follicle cells after gamma irradiation and after the topical application of chemical clastogens. Further exploring its potential application in aging research, researchers assayed expression patterns of selected markers of biological age and senescence in murine hair follicular cells. The researchers conducted many other tests and experiments using murine hair follicular cells in this study.

“The speed by which the samples can be collected and processed (e.g. by fixation) is among the biggest advantages of our solution as it can be performed within seconds. This fact limits any potential underlying cellular responses and additional DDR [DNA damage response] caused by cofounding stressing factors related to the withdrawal process [2].”

Conclusion

The researchers found that the follicular cells’ collector method of obtaining mouse hair follicular cells can be successfully used for genotyping, quantitative polymerase chain reaction testing and quantitative immunofluorescence. They also demonstrated that this method can successfully monitor quality and expression level changes of selected proteins—induced by external factors and during natural or experimentally induced aging. 

“Our results highlight the value of hair follicles as biological material for convenient in vivo sampling and processing in both translational research and routine applications, with a broad range of ethical and logistic advantages over currently used biopsy-based approaches.”

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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Trending With Impact: Aging Reduced by 8 Years With Rejuvant®

A recent study revealed that participants experienced an average 8 year reduction in biological aging after taking Rejuvant® for approximately 7 months.

Anti-aging hourglass

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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Waiting until the end of a subject’s lifespan is quite a leaden method of validating the efficacy of a longevity-based intervention. This method could take researchers generations upon generations to eventually validate an effective intervention—or—this method might not ever yield results seen by the general public. However, researchers may have devised an innovative way to solve this problem.

“If we hope to control the aging process, we need to learn how to measure the rate of aging in shorter time periods.”

Many researchers believe that measuring the rate of human aging can be done faster by using DNA methylation-based aging clocks. Methylation-based clocks are capable of determining human biological aging with impressive accuracy. Hypermethylated and demethylated regions of DNA (CpG islands near specific aging-associated genes) play a key role in turning certain genes on and off throughout the aging process. Therefore, methylation is a biomarker of aging. While there is a short list of currently available biological aging clocks for researchers to use in studies of anti-aging therapies, the TruAge DNA methylation test is preferable in some cases, due to its accessibility, use of simple saliva samples and cost effectiveness.

“For the first time, these biomarkers of aging give scientists the opportunity to study the effects of anti-aging compounds in real-time and directly in humans.”

In a new study, researchers from TruMe LabsNational University of Singapore and Ponce de Leon Health used the TruAge DNA methylation test to validate Rejuvant®—a patent-pending anti-aging dietary supplement. The trial study yielded unprecedented results and the research paper authored by the team was published as the cover of Aging (Aging-US) Volume 13, Issue 22, entitled: “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”.

The Study

Developed at Ponce de Leon Health, Rejuvant® is composed primarily of a compound called Alpha-Ketoglutarate (AKG). This molecule is naturally produced in humans and functions as a signaling molecule, an energy donor, a precursor to amino acid biosynthesis, and a regulator of epigenetic processes. In humans and other animals, AKG levels gradually decrease with age. Other components of Rejuvant® are calcium and, for males and females, Vitamin A and Vitamin D, respectively. 

“The goal of the study was to determine the effect of Rejuvant® supplementation on human biological aging by measuring DNA methylation.”

Researchers enrolled 42 healthy participants who were on average 64 years of age (43 to 72). Before taking Rejuvant®, all 42 participants completed a survey and their baseline biological age was measured using the TruMe age prediction model. The survey was a self-reported questionnaire including information about diet, alcohol intake, previous consumption of Rejuvant®, health, height and weight, sleep duration, smoking status, exercise frequency, physical activity level, meal frequency, snacking frequency, number of additional dietary supplements consumed and frequency, hair status, education, healthy lifestyle mindset, and trust in dietary supplements. 

Participants (majority male; 28) took two tablets of Rejuvant® daily, for a duration of four to 10 months. Biological age was measured from saliva samples again after taking Rejuvant® for four to 10 months. At the end of the trial, participants completed the same survey. The researchers compared the baseline surveys with the final surveys to check for other confounders contributing to the results in the study. They also used the surveys to select a sub-group of 13 participants who reported no change in diet type, drinking frequency, additional dietary supplements intake, sleep duration, and exercise frequency. They compared this sup-group with the rest of the cohort. They also compared results between males and females, older and younger participants, and participants with higher biological age relative to their chronological age (aging more quickly).

Results and Conclusion

Researchers examined associations between the epigenetic clock, health status, physical fitness, and the effects of Rejuvant® on human biological aging. The researchers were forthcoming about limitations in this study. A control arm was not used, the cohort was relatively small, only one biological aging clock was used, and researchers did not collect other kinds of data relevant to aging. However, the study results showed that Rejuvant® conferred an average eight year reduction in biological aging after approximately seven months of use. The 13 participants in the sub-group saw anti-aging benefits slightly less than the rest of the cohort. Rejuvant® was more effective in chronologically older participants and in participants that were aging more quickly (with a higher biological age relative to their chronological age).

“Future randomized clinical trials will be required to confirm the findings presented here. Nevertheless, the results in this manuscript suggest that Rejuvant® may have significant effects on biological age as measured by DNA methylation of saliva samples.”

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 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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Trending With Impact: Worms Reveal Early Event in Neurodegeneration

Researchers examined roundworms to determine the role of mitochondrial dysfunction in progressive neurodegenerative disorders, such as Alzheimer’s disease.

From Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae. (truncated)
From Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae. (truncated)

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Many aging-associated neurodegenerative disorders, including Alzheimer’s disease, involve the aggregation of abnormal tau in nerve cells (neurons). Normally, tau proteins function to stabilize microtubules in the brain. Tauopathy occurs when tau proteins become misfolded and misshapen (which turns tau into toxic tau). They then continue to proliferate and bind to each other, forming tau oligomers. These tau oligomers are more toxic and have a greater potential to spread tau pathology. Before the tau pathology snowballs into neurodegenerative disorders, the events that lead up to abnormal tau have remained elusive to researchers. 

“While the association between tau levels and energy metabolism is established, it is not clear whether mitochondrial dysfunction is an early pathological feature of high levels of tau or a consequence of its excessive formation of protein aggregates.”

Previous studies have demonstrated an association between tau levels and mitochondrial metabolism, however, determining which one proceeds the other has yet to be fully illuminated. Shedding light on this subject, researchers—from the University of CopenhagenNational and Kapodistrian University of Athens and the National Institutes of Health’s National Institute on Aging—used a Caenorhabditis elegans (C. elegans; roundworm/nematode) model of tau to examine mitochondrial changes over time. Their paper was chosen as the cover of Aging (Aging-US) Volume 13, Issue 21, published in November of 2021 and entitled, “Alteration of mitochondrial homeostasis is an early event in a C. elegans model of human tauopathy”.  

The Study

“Here, we utilized transgenic nematodes expressing the full length of wild type tau in neuronal cells and monitored mitochondrial morphology alterations over time.”

To investigate the impact of tau on mitochondrial activity, neuronal function and organismal physiology, the researchers selected and cultured an already characterized nematode strain that expresses the full length of wild type human tau protein. They compared wild type nematodes with tau-expressing nematodes (at various ages) over time using a thrashing assay, mitochondrial imaging, worm tracking software, and western blot analysis. Calcium deregulation was also examined to determine whether or not it is implicated in the impairment of mitochondrial activity in the tau-expressing nematodes. They found that chelating calcium led to restored mitochondrial activity and suggested a link between mitochondrial damage, calcium homeostasis and neuronal impairment in this nematode model.

Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae.
Figure 2. Altered mitochondrial morphology and activity in tauwt-expressing larvae.

Conclusion

“Our findings suggest that defective mitochondrial function is an early pathogenic event of tauopathies, taking place before tau aggregation and undermining neuronal homeostasis and organismal fitness.”

The researchers were forthcoming about limitations in their study, given the differences between human and nematode biology and pathology. Nevertheless, they found evidence that, in this nematode tauopathy model, neurotoxicity depends on protein alterations and mitochondrial dysfunction. Mitochondrial dysfunction takes place before high levels of tau are detected. Tau mutations may also modulate calcium homeostasis by influencing the main cellular storage sites—the endoplasmic reticulum and mitochondria.

“Investigating the tight interplay between tau oligomers and energy metabolism will enlighten new avenues for therapeutic strategies to slow or halt the progression of dementia-related diseases such as AD [Alzheimer’s disease].”

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 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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Trending With Impact: Can Singing Improve Aging?

In a two-year study, researchers compared the effects of choral singing with the effects of health education in an elderly cohort.

Couple singing

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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There may be many paths that lead to the cessation of aging, or there may only be one—this mystery has yet to reveal itself. However, there is a wide array of evidenced methods capable of preserving youth by slowing down the aging process, and even mildly reversing it. Some known natural interventions are healthy diets, consistent exercise and avoiding aging-related risk factors, including carcinogens such as alcohol, cigarettes and excess sun exposure. Researchers have also studied less intuitive repetitive behaviors that appear to improve the cognitive decline associated with aging. For example, in a study published in 2015, researchers found that active singing led to cognitive improvements in participants with dementia. 

“People engaging in lifelong music-making have been found to have better cognitive outcomes later in life.”

In a research study published in 2020, 30 researchers—from National University of SingaporeSingapore Institute for Clinical SciencesNational University Health SystemUniversity of CambridgeUniversity of LondonSingapore Immunology NetworkMaurine Tsakok IncVoices of Singapore Choral SocietyPresbyterian Community ServicesNTUC Health Co-operative Limited, Beijing Chui Yang Liu Hospital, Fudan UniversityMassachusetts General HospitalHarvard Medical SchoolNanyang Technological UniversityImperial College London, and Genome Institute of Singapore—conducted the world’s first study designed to compare the impact of choral singing versus health education on cognitive function and aging in a randomized controlled trial (RCT). Their trending research paper was published by Aging (Aging-US) in 2020 and entitled, “Effects of choral singing versus health education on cognitive decline and aging: a randomized controlled trial”.

“In this RCT, we hypothesized that choral singing would improve cognitive health and/or reduce cognitive decline in elderly with high risk of dementia.”

The Study

This study, based out of Singapore, was designed for half of the subjects to participate in a choral singing program for one hour every week, over the course of two years. This program was conducted at the National University of Singapore’s Yong Siew Toh Conservatory of Music. In these sessions, professional musicians taught the fundamental concepts and mechanics of “good” singing, including breathing techniques, harmonies, memorization and listening skills. Participants also prepared to sing in public performances to promote motivation, purpose, pride and accomplishment.

“Each session incorporated the musical, social, and physical aspects of choral singing.”

Forty-seven participants were randomly assigned to the choral singing intervention (CSI) arm, and 46 were assigned to the health education program (HEP) arm. Parallel to the CSI participants, HEP participants completed a weekly one-hour health education session at the Training and Research Academy at Jurong Point for two years. Family physicians, specialist clinicians and community nurses facilitated these sessions, which included short talks on health-related topics, group activities, memory work, and physical activities (not including singing).

At baseline, the researchers collected demographic and clinical characteristics from each participant. Characteristics included: age, gender, education, marital status, living situation, status of hypertension, diabetes mellitus, heart diseases, average composite cognitive test score, Singapore Modified Mini-Mental State Examination (SM-MMSE) score, and Geriatric Depression Scale (GDS). Follow-up assessments were conducted at two additional times throughout the study—after year one and year two of the programs. Researchers assessed the effects of both these programs on brain imaging, immune system and oxidative damage markers.

“Our study is the first randomized trial in the world that systematically assessed the effects of singing on cognitive decline in aging and the potential effects on brain imaging, immune system and oxidative damage markers.”

Results and Conclusion

The researchers were forthcoming about limitations in this study. The cohort was small and they did not include a non-intervention control arm; researchers were only able to compare the effects of choral singing to the effects seen in the health education cohort. The team did, however, observe an increase in the mean composite cognitive test scores among participants in the singing group, and a decrease in the mean composite cognitive test scores among participants in the health education group. They did not observe differences in brain aging, oxidative damage or immunosenescence.

“Our findings from the very first RCT on this topic suggest that choral singing is a potentially useful intervention for the promotion of cognitive health in aging. Choral singing is a safe and enjoyable activity, and is likely to be embraced by the community. Policy makers may consider promoting choral singing for healthy and active aging of seniors in the community. This is especially relevant for countries where existing resources are available.”

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 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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Trending With Impact: Machine Learning Predicts Human Aging

Machine learning and a broad range of biochemical and physiological traits were used to develop a new composite metric as a potential proxy for an underlying whole-body aging mechanism.

Algorithms

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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Will you age quickly or slowly? Is it possible to predict how long you will live based on your genetics, lifestyle and other traits? In a new study, a team of researchers—from the National Institutes of Health’s National Institute on Aging, University of California San Diego, University of Michigan, Consiglio Nazionale delle Ricerche, Azienda Sanitaria di Firenze, and ViQi, Inc.—sought to answer these questions by developing a novel framework designed to estimate human physiological age and aging rate. Their trending paper was published by Aging (Aging-US) in October 2021, and entitled, “Predicting physiological aging rates from a range of quantitative traits using machine learning”.

“We present machine learning as a promising framework for measuring physiological age from broad-ranging physiological, cognitive, and molecular traits.”

Machine Learning

Machine learning is an important development in computer science that uses artificial intelligence. Algorithms and data (figured and input by human intelligence) are programed to automatically learn and improve through experience and new data. Machine learning approaches allow researchers to build mathematical models onto training data to predict target variables—target variables including human physiological age and rate of aging.

“Here we use a machine learning approach with a broad range of biochemical and physiological traits including blood phenotypes (e.g., high-density lipoprotein), cardiovascular functions (e.g., pulse wave velocity) and psychological traits (e.g., neuroticism) as main groups from the SardiNIA longitudinal study of aging [48, 49] to estimate human physiological age, a metric for phenotypic and functional age progression [7].”

Subjects and Traits

Two very interesting study populations were included in this particular aging model. People living in Sardinia—an island off the coast of Italy and one of the first identified “Blue Zones”—are well-known for their long lives. They are currently contributing to a large longitudinal study on human aging, known as the SardiNIA Project. Data from the SardiNIA Project was used to develop the aging model in the current study. 

“Funded by the National Institute on Aging in 2001, the SardiNIA Project (age range 14.0 to 101.3 years, with a mean of 43.7 years; 57% female) is a longitudinal study of human aging on the island of Sardinia, which is notable for its long-lived population [48, 49].”

The second cohort included in the current study was collected from the InCHIANTI study. Participants in this longitudinal population-based study were predominantly older adults living in Tuscany, Italy. After collecting the initial datasets from both cohorts, the researchers reduced the datasets using a “cleaning” strategy they developed. After cleaning, the number of subjects in the study went from 6165 to 4817, and the number of traits included in the algorithms went from 183 to 148. The researchers then configured the selected subjects and traits using computational algorithms and machine learning. Traits were ranked based on importance and weighted accordingly using algorithms the researchers developed. Study methods and materials were detailed thoroughly in the paper and its supplemental materials.

Supplementary Figure 1. Computational workflow for measuring physiological age and physiological aging rates (PAR) using the machine learning framework.
Supplementary Figure 1. Computational workflow for measuring physiological age and physiological aging rates (PAR) using the machine learning framework.

Conclusion

The team developed a promising new composite metric and was able to closely predict chronological age using their machine learning strategy. After they effectively estimated physiological age and validated their results, the researchers then used the ratio of physiological and chronological age to determine physiological aging rate, or PAR. Interestingly, the researchers observed that PAR was highly correlated with the epigenetic aging rate (EAR), which is a DNA methylation-based measure of aging. In addition, the researchers demonstrated that individuals with lower PARs outlived individuals with higher PARs. PAR may be a new proxy for an underlying whole-body aging mechanism.

“The efficacy of treatments aimed at slowing the aging process has traditionally been evaluated using individual biomarkers or limited collections of related biomarkers. Our current study has shown that PAR is a significant predictor for survival and correlated with epigenetic aging rate, providing evidence for a good measurement of ‘aging’.”

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 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 media@impactjournals.com.

Trending With Impact: Is Iron a Driver of Aging?

In a trending theory article, Dennis Mangan proposes several reasons why iron may be a key driver of aging.

Iron mineral rock
Iron mineral rock

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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Iron is a mineral naturally found in the environment on Earth, within food sources and in all living organisms. A number of biochemical systems require this mineral and, in humans, the lack of iron results in anemia and a deficiency in hemoglobin—the protein responsible for supplying the body with oxygen. Anemia can also be caused by iron dysregulation. This occurs when iron damages the protein it should be safely stored in, such as ferritin, and then reacts in a toxic manner with surrounding cellular structures and organs. While iron is essential, the chemical properties of iron can make it a harmful substance if it is not tightly regulated.

“The very property of iron that makes it useful, its ability to accept or donate electrons, also gives it the ability to damage molecules and organelles via the Fenton reaction, in which iron reacts with hydrogen peroxide, leading to the formation of the highly reactive and toxic free radical, hydroxyl.”

Dennis Mangan (P. D. Mangan) is a clinical biochemist/microbiologist, researcher, authorhealth and fitness expert, and anti-aging specialist. In October of 2021, he authored a new theory article that positions iron as a potential driver of aging. This trending paper was published in Aging (Aging-US) Volume 13, Issue 19, and entitled, “Iron: an underrated factor in aging.”

Iron and mTOR

There is an undeniable correlation between the accumulation of iron, DNA damage and age-related diseases. Excess iron levels are measurable in age-related illnesses, including cardiovascular disease, diabetes, cancer, and Alzheimer’s disease. In his paper, Mangan explains the important relationship between iron and the mammalian target of rapamycin (mTOR). Iron can act as a growth factor to activate mTOR. Crosswise, mTOR is capable of regulating iron metabolism.

“mTOR activation in diabetes may be responsible for the accumulation of excess iron seen in this illness; alternatively, accumulation of iron might activate mTOR, leading to diabetes.”

Researchers have demonstrated that inhibiting mTOR can extend lifespan and healthspan in animal models. The inhibition of mTOR, by drugs such as rapamycin, inhibits the accumulation of iron through an iron-regulating hormone called hepcidin. Therefore, it would be reasonable to assert that the over-activation of mTOR in diseases such as diabetes may be due to excess iron, or, excess iron may lead to diabetes through the over-activation of mTOR.

Sans Iron

Studies on experimental organisms, such as fruit flies, brewers yeast, roundworms and mice, have shown that the inhibition of iron leads to life extension. Mangan uses a number of natural iron chelators as examples, such as green tea catechins and curcumin. Calorie restriction is a highly effective life-extending intervention, and also a powerful regulator of iron metabolism. He lists iron inhibiting/chelating drugs, such as metformin, enalapril, quercetin, aspirin, tannic acid, ciclopirox, acetaminophen, bacitracin, berberine and baicalein.

“Thus, we can see that a large number of life-extending compounds also interact with iron, either by chelation, inhibition of absorption, or increased iron loss.”

Mangan also refers to a 2020 study which replaced 50% of blood plasma with saline, plus 5% albumin. To summarize their study, the researchers observed “rejuvenating” effects due to the dilution of old factors in the blood plasma. Similarly, elderly blood donors have experienced rejuvenating effects after donating blood. Mangan proposes that the critical old factor that was diluted was iron.

“Other components of plasma may be removed or diluted as well, but iron may be the critical element here.”

Conclusion

Mangan wrote a thought-provoking paper—far more detailed than this blog summary. He emphasizes that, since iron is both biologically needed and likely contributes to aging and disease, sufficient iron storage and regulation may be critical for the efficacy of upcoming anti-aging therapies that may be developed to extend lifespan. 

“In sum, iron satisfies many of the conditions we might look for in a universally pro-aging substance. It accumulates with age; it is associated with many age-related diseases such as cardiovascular disease, cancer, and Alzheimer’s disease; it catalyzes the formation of cellular junk molecules and helps to prevent their turnover; removal of iron from plasma may be rejuvenating; and people with lower levels of body iron – blood donors – have a lower mortality rate.”

Click here to read the full theory article published by Aging (Aging-US).

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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 media@impactjournals.com.

Trending With Impact: Green Tea Enhances Fitness and Lifespan in Worms

The mechanisms and pathways involved in the health and aging benefits conveyed by green tea were investigated in C. elegans.

Green tea leaves

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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Boiled or iced with water or milk, blended in smoothies, condensed into shots or even baked into pastries—humans are infatuated with green tea. Today, green tea is one of the most widely consumed beverages in the world. Molecules found in this plant, named catechins, are known to have numerous evidence-based health benefits, including weight loss and age delaying properties. However, the mechanism by which these effects take place have yet to be fully elucidated.

“The popularity of green tea makes it crucial to study its impact on health and aging.”

Researchers from Friedrich Schiller University JenaHuazhong Agricultural UniversityETH Zurich, and the Medical University of Graz investigated green tea catechins and their effects in roundworms, known as Caenorhabditis elegans (C. elegans), and isolated rodent mitochondria. Their trending paper was published in October of 2021 by Aging (Aging-US), and entitled, “Green tea catechins EGCG and ECG enhance the fitness and lifespan of Caenorhabditis elegans by complex I inhibition.”

“We have designed the current study to investigate the impact and to unveil the target of the most abundant green tea catechins, epigallocatechin gallate (EGCG) and epicatechin gallate (ECG).”

The Study

In this study, the researchers focused on testing two of the most common green tea catechins, epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), in isolated mitochondria from murine liver and C. elegans. C. elegans are approximately one millimeter long nematodes, or roundworms, and have been used in a variety of biomedical studies. The reason C. elegans were chosen for this study is likely due to the fact that many genes in C. elegans have functional counterparts in humans. (C. elegans also have the ability to “smell” cancer.)

Over the course of 24 hours or seven days, C. elegans and rodent mitochondria were treated with 2.5 μM of EGCG and/or ECG compounds. To analyze the green tea catechins’ effects on cellular metabolism, reactive oxygen species (ROS) homeostasis, stress resistance, physical exercise capacity, health- and lifespan, and on the underlying signaling pathways, the researchers conducted lifespan analyses, locomotion assay, paraquat stress resistance assay, basal oxygen consumption rate, ROS quantification, glucose oxidation assay, ATP quantification, activity assays for catalase and superoxide dismutase, fat content analysis, quantification of complex I activity in mitochondria, quantification of oxygen consumption rate in mitochondria, and statistical analyses.

“We conclude that applying the green tea catechins EGCG and ECG at a low dose extends the lifespan of C. elegans via inducing a mitohormetic response.”

They found that the catechins hindered mitochondrial respiration in C. elegans after 6–12 hours, the activity of complex I in isolated rodent mitochondria and temporarily increased ROS levels. Then, after 24 hours and through adaptive responses, catechins reduced fat content, enhanced ROS defense and, in the long term, improved healthspan in C. elegans.

Conclusion

Mechanisms and pathways observed to be involved in this process of C. elegans fitness and lifespan extension by green tea were further described in the paper. The researchers note that additional studies will be required to determine the best timing and dosage for administering catechins. They also acknowledge that the low bioavailability of green tea catechins may limit the lifespan extending effects of green tea in humans, despite the promising effects demonstrated in C. elegans.

“Despite the promising results obtained in animal experiments, the low bioavailability of EGCG [7] still raises the question of whether green tea catechins can reliably provoke beneficial effects in humans. Consequently, additional efforts might be needed to identify complex I inhibitors with increased bioavailability.”

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

WATCH: AGING VIDEOS ON LABTUBE

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 media@impactjournals.com.

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