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Exploring the Impact of Cognitive Reserve on Cognitive Resilience

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In a new editorial, researchers discuss their recent study investigating the effect that cognitive reserve has on brain integrity and cognitive resilience.

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Why do some individuals maintain cognitive abilities throughout their lifespan and others do not? The better question may be: How can certain individuals preserve their cognitive abilities and delay the onset of dementia despite the presence of significant neuropathologies that would otherwise suggest cognitive decline? This question remains unanswered.

“What contributes to this ‘resilience’ [3], that is why some successfully cope with progressive neuropathology while others cannot tolerate the same level of neurodegeneration, is not fully understood.”

This unanswered question has driven researchers to consider the idea of “cognitive reserve.” The rather new concept of cognitive reserve suggests that certain factors, such as engaging in education, mental stimulation and challenging activities, can create a buffer against cognitive decline and delay the onset of cognitive impairment or dementia. Researchers continue to study cognitive reserve to better understand its mechanisms and potential implications for maintaining brain health and designing effective interventions.

In a new editorial paper, researchers Monica E. Nelson, Ross Andel and Jakub Hort from the University of South Florida’s​​ School of Aging Studies discussed the outcomes, lessons and future implications of their previous 2022 study. The team examined the influence of cognitive reserve proxies on the relationship between brain integrity and cognition. On July 14, 2023, their editorial was published in Aging’s Volume 15, Issue 13, entitled, “Cognitive reserve, neuropathology, and progression towards Alzheimer’s disease.”

Cognitive Reserve’s Effect on Brain Integrity and Cognitive Performance

In their 2022 study, a total 570 older adult participants were assessed from the Czech Brain Aging Study (a longitudinal cohort study from two memory clinics in the Czech Republic). Most of the participants (n = 457) were without dementia (including those with subjective cognitive decline and amnestic mild cognitive impairment) and the remaining participants were with dementia syndrome (n = 113). The researchers examined the influence of education and occupational position (cognitive reserve proxies) on the relationship between the participants’ hippocampal or total gray matter volume and cognitive performance. Measurements included brain volume, executive control, language, memory, attention/working memory, and visuospatial skills.

“[…] we assessed the inter-link between cognitive reserve, neuropathology, and cognitive functioning among participants with subjective cognitive decline, mild cognitive impairment, and dementia.”

The team found that the association between brain volume and cognitive performance varies based on cognitive reserve. Findings showed that a higher education and occupational position magnified the associations between brain volume and cognitive performance in participants without dementia. In participants with dementia, higher education decreased the associations between brain volume and visuospatial skills. Overall, the results showed that cognitive reserve affects the relationship between brain volume and cognitive performance, with greater cognitive reserve related to a stronger link before dementia diagnosis and a weaker link after.

Future Directions 

In their subsequent editorial, the researchers were forthcoming about limitations of this study and addressed key opportunities for future studies. Limitations were identified as the use of a relatively homogeneous sample population, the absence of the use of biomarkers in diagnosis and the cross sectional design. Cross-sectional studies may not fully capture disease-related changes in neuropathology and could present a distorted view of the linkages between cognitive reserve, neuropathology and cognitive outcomes. The authors advocate for conducting longitudinal studies to track how cognitive reserve operates in individuals as they progress from normal to dementia. 

Additionally, the team wrote that future studies would be improved by investigating a range of Alzheimer’s disease biomarkers, such as beta-amyloid and tau, individually and together, to understand how they influence the associations between cognitive reserve, brain health and cognition. Different biomarkers may lead to varied results in how cognitive reserve moderates these associations. And finally, future studies should also assess older adults across the cognitive spectrum to determine when cognitive reserve is protective against brain health decline and neuropathology, and when its effectiveness diminishes. Some researchers have suggested a U-shaped relationship to explain mixed findings in different studies.

“Even though our study represents one of the first to come from Eastern Europe [4], future work should be conducted in additional populations, representing geographic, racial, and socioeconomic diversity.”

Implications

The potential impact of this research may be important, as it could lead to the development of effective interventions and strategies to preserve cognitive abilities and delay the onset of dementia. By gaining a deeper understanding of cognitive reserve and its mechanisms, we can take steps to promote brain health throughout life, potentially reducing the burden of dementia on individuals, communities and society overall.

As research continues in this field, it is clear that cognitive reserve holds great promise for unlocking the secrets of cognitive resilience and paving the way for healthier aging and improved quality of life for older adults. By addressing the limitations of current studies and exploring new avenues of investigation, we move closer to finding answers to the vital question of how some individuals maintain their cognitive abilities despite the presence of significant neuropathologies, while others do not.

“By assessing cognitive reserve in distinct populations, a more complete understanding of how cognitive reserve relates to neuropathology and cognition and whether these associations may be affected by distinct macro-level contextual differences among populations can be established. Disentangling these complex relationships may provide a critical step in reducing the impact of dementia on society.”

Click here to read the full editorial published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

Click here to subscribe to Aging publication updates.

For media inquiries, please contact media@impactjournals.com.

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How Telomere Dysfunction Affects Female Fertility (A Mouse Study)

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In a new study, researchers aimed to reveal a link between telomere dysfunction, ovarian aging and infertility using a mouse model of accelerated-reproductive senescence.

Telomeres are the protective caps at the ends of chromosomes that prevent DNA damage and maintain genomic stability. However, telomeres shorten with each cell division and eventually reach a critical length that triggers cellular senescence or death. Telomere length (TL) and telomerase activity (TA), the enzyme that replenishes telomeric repeats, are influenced by genetic and environmental factors and vary among tissues and individuals.

“Telomere attrition has been identified as one of the molecular determinants of aging [7].”

Telomere dysfunction has been implicated in various age-related diseases, including infertility. Ovarian aging is the main cause of infertility in women, as it leads to a decline in both the quantity and quality of oocytes. Previous studies have shown that TL and TA are reduced in oocytes and granulosa cells of women with diminished ovarian reserve or poor response to ovarian stimulation. Moreover, TL and TA have been associated with ovarian reserve markers and pregnancy outcomes in assisted reproductive technologies.

To better understand the molecular mechanisms underlying ovarian aging and infertility, researchers Alba M. Polonio, Marta Medrano, Lucía Chico-Sordo, Isabel Córdova-Oriz, Mauro Cozzolino, José Montans, Sonia Herraiz, Emre Seli, Antonio Pellicer, Juan A. García-Velasco, and Elisa Varela from The Health Research Institute La Fe (IIS La Fe), IVIRMA Rome, New Jersey and Madrid, Centro Anatomopatológico, Yale School of Medicine, University of Valencia, and Rey Juan Carlos University conducted a new study using a mouse model of accelerated aging: the Senescence-Accelerated Mouse Prone 8 (SAMP8). On May 23, 2023, their research paper was published in Aging’s Volume 15, Issue 11, entitled, “Impaired telomere pathway and fertility in Senescence-Accelerated Mice Prone 8 females with reproductive senescence.”

The Study

The SAMP8 mouse model, which has previously been suggested as an Alzheimer’s disease model of aging, also exhibits a shortened estrous cycle, elevated follicle-stimulating hormone (FSH) levels, and reduced fertility in females at just seven months of age. SAMP8 mice have a shorter lifespan compared to senescence-accelerated mouse resistant 1 (SAMR1) mice. SAMR1 mice do not exhibit reproductive senescence. Thus, the researchers deemed the SAMR1 mouse model an appropriate control group to study the SAMP8 mouse model as a model of ovarian aging and infertility. 

“In the current study, we sought to investigate whether the SAMP8 mice, which show accelerated-reproductive senescence, have alterations in their telomere pathway. This question has not yet been explored in relation to reproduction in this model.”

In this study, the team compared the TL and TA in blood and ovary samples from the SAMP8 female mice at seven months of age (when they show signs of reproductive senescence) with age-matched control SAMR1 mice. They also evaluated the ovarian follicle development, the expression of telomerase subunits (TERT and TERC), and the reproductive outcomes after ovarian stimulation in both groups of mice. In sum, the researchers measured survival rates (in male and female mice), alteration in the telomere pathway at seven months of age, TERT and TERC expression levels, TA on the TL of granulosa cells in developing follicles, and impairment/alterations in the telomere pathway in oogenesis and embryo development.

The results revealed that SAMP8 females had a reduced median lifespan compared to SAMP8 males and SAMR1 males and females. In blood, SAMP8 females had lower mean TL and higher accumulation of short telomeres than the other mice. In ovary, SAMP8 females had lower TA and TERT expression. Furthermore, SAMP8 females had fewer primordial, primary, secondary, and antral follicles than control females, indicating a diminished ovarian reserve. After ovarian stimulation, SAMP8 females had a lower number of oocytes than controls of the same age. Their results suggested that oogenesis and embryo development is impaired in SAMP8 mice at seven months compared to age-matched controls, and this coincides with alterations in the telomere pathway.

Conclusions

“Thus, SAMP8 females represent a bona fide model for the analysis of fertility, not only because it shows similar phenotype to middle-aged women as stated earlier [43], but also because the alterations in the telomere pathway are found in women with fertility disorders [37, 38, 40, 41] and this pathway links reproduction with longevity.”

The researchers concluded that SAMP8 females have impaired telomere pathway and fertility, reflecting signs of reproductive senescence described in middle-aged women. They suggested that the SAMP8 model could be useful in studying the role of telomere dysfunction in ovarian aging and infertility. In addition, this mouse model could be used to test potential therapeutic interventions to improve female reproductive health.

“Understanding the molecular pathways underlying aging and fertility, provides a basis for further studies focused on several topics. First, the analysis of embryo alterations, which can be better assessed in mice than in humans. Second, how reproductive lifespan improvement may ameliorate elderly health. And third, the mechanisms underlying follicle recruitment and development, which are not completely known.”

Click here to read the full research paper published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

Click here to subscribe to Aging publication updates.

For media inquiries, please contact media@impactjournals.com.

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The Impact of Age, Sex, CMV, and Smoking on Circulating Immune Cells

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In a new study, researchers investigated associations between circulating immune cells and age, sex, CMV infection, and smoking.

The Impact of Age, Sex, CMV, and Smoking on Circulating Immune Cells

As we age, our immune system undergoes changes that influence our susceptibility to various diseases. Certain factors, such as smoking, viruses, age, and sex can have differential impacts on our various circulating immune cells. How changes to these immune cells contribute to cardiovascular disease and other age-related diseases is not yet fully understood. More research is needed to fully understand the underlying mechanisms and implications. 

“Understanding the composition of circulating immune cells with aging and the underlying biologic mechanisms driving aging may provide molecular targets to slow the aging process and reduce age-related disease.”

In a new study, researchers Yuan Fang, Margaret F. Doyle, Jiachen Chen, Jesse Mez, Claudia L. Satizabal, Michael L. Alosco, Wei Qiao Qiu, Kathryn L. Lunetta, and Joanne M. Murabito from Boston University, Boston Medical Center, University of Vermont, and University of Texas Health Science Center aimed to characterize the circulating innate and adaptive immune system by profiling immune cell phenotypes from a community-based cohort. Their research paper was published in Aging’s Volume 15, Issue 10, on April 27, 2023, entitled, “Circulating immune cell phenotypes are associated with age, sex, CMV, and smoking status in the Framingham Heart Study offspring participants.”

“We hypothesize that we will identify immune cell phenotype and ARIP [age-related immune phenotype] measure associations with CMV serostatus, age, and sex, as well as associations with cardiovascular risk factors.”

The Study and Participant Characteristics

The Framingham Heart Study (FHS) is a community-based prospective cohort study that began in 1948. It initially recruited 5,209 primarily white American adults of European ancestry as the Original cohort. In 1971, the Offspring cohort was established, consisting of the children of the Original cohort and their spouses. The Offspring participants have been examined every 4-8 years since enrollment. 

For this study, 1,332 Offspring participants who attended exam seven (1998 to 2001) and had two or more vials of stored peripheral blood mononuclear cells (PBMCs) were identified. From this group, a study sample of 996 dementia-free individuals, aged 40 years and older, was selected. This cohort had a mean age of 62 years, with 52% representing males. All participants provided written informed consent, and the FHS exams were approved by the Institutional Review Board at Boston University Medical Center.

The research team used cryopreserved cell samples from the study participants to conduct comprehensive analyses of 116 circulating immune cell phenotypes, including subtypes of CD4 and CD8 T cells, B cells, NK cells, and monocytes. These subsets were further categorized based on specific surface markers to provide a detailed characterization of the immune cell populations.

The Results

Significant associations between circulating immune cell phenotypes and age, sex, a common virus, and smoking were revealed in this study. With advancing age, researchers saw a decline in the overall number of immune cells, as well as alterations in the distribution of different immune cell subsets. Notably, older individuals exhibited a higher proportion of memory T cells and a lower proportion of naive T cells, suggesting a shift towards a more experienced immune profile. Furthermore, females exhibited a higher abundance of immune cells compared to males, which may contribute to their generally stronger immune responses.

Cytomegalovirus (CMV), a common herpesvirus, can have a profound impact on the immune system. The study found that CMV seropositivity was associated with distinct alterations in immune cell phenotypes. CMV-positive individuals displayed higher numbers of late-stage differentiated effector memory T cells, which are indicative of previous exposure to CMV. This observation suggests that CMV infection contributes to the age-related changes in immune cell populations.

Smoking has long been recognized as a detrimental habit that affects overall health, including the immune system. This study uncovered compelling evidence linking smoking status to immune cell phenotypes. Smokers exhibited a higher proportion of pro-inflammatory immune cells, such as activated T cells and pro-inflammatory monocytes, while non-smokers had a higher proportion of regulatory T cells that help maintain immune balance. These findings emphasize the detrimental impact of smoking on immune cell profiles and further underscore the importance of smoking cessation.

“Importantly, we did not identify significant immune cell associations with other risk factors, such as body mass index, prevalent cardiovascular disease, hypertension or diabetes.”

Conclusions

“Our observations confirm and extend known associations of immune cell subtypes with CMV and age that show a shift from a naïve phenotype towards an exhausted phenotype. We report sex differences, with males exhibiting a more exhausted, cytotoxic landscape than females. We identified associations between CD8 exhausted cells and B cell subsets, but not overall B cells, with smoking status.” 

This research provides valuable insights into the relationship between circulating immune cell phenotypes and age, sex, CMV infection, and smoking status. In conclusion, the team did not find significant associations between these immune cells and cardiovascular risk factors. They did find some weak associations with cardiovascular disease, diabetes and hypertension. The findings contribute to our understanding of age-related changes in the immune system and highlight the impact of lifestyle factors on immune health. By unraveling the complex interplay between these variables, this study paves the way for future research on interventions and strategies to support healthy immune aging.

“While further studies in larger, more diverse sample[s] and more than one time point with immunophenotypic data are needed, this work will provide a valuable resource for future studies of the association of immune cell phenotypes and incident age-related disease.”

Click here to read the full research paper published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

Click here to subscribe to Aging publication updates.

For media inquiries, please contact media@impactjournals.com.

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Brain Aging Insights from Individuals Without Neurodegeneration

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The Trending With Impact series highlights Aging publications (listed by MEDLINE/PubMed as “Aging (Albany NY)” and “Aging-US” by Web of Science) 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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A healthy brain continuously produces new proteins to support synaptic plasticity, maintain neuronal health, facilitate signaling pathways, produce neurotransmitters, enable neuroplasticity and adaptation, and meet its metabolic demands. These processes are essential for normal brain function, learning, memory, and overall cognitive abilities. Researchers believe that the dysregulation of proteins is at the core of brain aging. However, the exact recipe for protein dysregulation that leads to accelerated brain aging and neurodegenerative disorders has yet to be brought to light. 

Previous brain proteostasis (referring to the maintenance of protein homeostasis in brain cells) studies in individuals with Alzheimer’s disease (AD) pathology and age-related neuropathological changes have shown protein dysregulation leading to a buildup of amyloid plaques and neurofibrillary tangles. While these studies have greatly enhanced our knowledge of brain aging, gaps in our understanding remain. What proteomic characteristics do healthy brain aging individuals—without neurodegenerative disorders—have in common?

“To our knowledge, whole phosphoproteomes centered on the human brain aging without AD pathology are unavailable.”

In a new study, researchers Pol Andrés-Benito, Ignacio Íñigo-Marco, Marta Brullas, Margarita Carmona, José Antonio del Rio, Joaquín Fernández-Irigoyen, Enrique Santamaría, Mónica Povedano, and Isidro Ferrer from Bellvitge Institute for Biomedical Research, Universidad Pública de Navarra, Barcelona Institute for Science and Technology, and University of Barcelona aimed to shed light on the mechanisms underlying brain aging in the absence of AD pathology and age-related neuropathological changes. Their research paper was published on May 13, 2023, in Aging’s Volume 15, Issue 9, and entitled, “Proteostatic modulation in brain aging without associated Alzheimer’s disease-and age-related neuropathological changes.”

The Study

The production of new proteins is crucial for maintaining protein homeostasis in the brain. A post-translational modification used to maintain this homeostasis is protein phosphorylation. In this study, the researchers conducted proteomic and phosphoproteomic analyses of frontal cortex samples from the donor brains of deceased individuals between the ages of 30 and 85. These individuals had passed away due to non-neurological complications and were reported to have had full cognitive function. Individuals were divided into four groups: young group one (30–44), middle-aged group two (45-52), early-elderly group three (64–70), and late-elderly group four (75–85).

“​​We chose the FC [frontal cortex] because of its role in cognition and emotion and the abundant molecular information that permits comparison with other studies.”

Conventional label-free- and SWATH- (sequential window acquisition of all theoretical fragment ion spectra) mass spectrometry were used to assess the (phospho)proteomes of the frontal cortices from individuals in all four age groups. Immunohistochemistry and/or western blotting was/were also used to validate a subgroup of proteins. The researchers categorized deregulated proteins and phosphoproteins into eight clusters based on their age-dependent expression similarity (see paper for clusters). Interestingly, protein and phosphoprotein levels of the larger hierarchical clusters were stable until the age of 70 years. After 70, the late-elderly group showed significant decreased or increased expression of protein clusters one and seven, and major phosphorylation modifications occurred in clusters four and eight.

Results

The team then used multi-comparative analyses to categorize altered proteins and phosphoproteins as neuronal, astroglial, oligodendroglial, microglial, and endothelial. They observed a similar pattern among proteomic and phosphoproteomic alterations: major changes were related to neuronal cell populations across all four groups—and these changes were more pronounced with age. Cytoskeletal and membrane proteins accounted for the largest number of differentially-expressed proteins and phosphoproteins.

“Furthermore, main alterations in the proteome are associated with proteins specific to neuronal populations, rather than those found in other cell types in the brain.”

Their findings also revealed a decline in the expression of P20S α + β with aging, while the expression of P19S and immunoproteasome subunits LMP2 and LMP7 remained preserved. Notably, the expression levels of an autophagy component, ATG5, remained unchanged with age. Some mitochondrial membrane proteins showed altered levels at advanced ages, but key markers of mitochondrial function were preserved. These findings suggest a potential preservation of these pathways in advanced aging, contrasting with observations in neurodegenerative disorders. Additionally, reduced levels of GSK3α/β were observed, and the researchers point out that this decrease in GSK3α/β with age may be understood as protective against different age-related brain diseases.

Summary & Conclusion

“Therefore, our results fill the gap between brain ageing without ADNC [AD neuropathological changes], and cases with early and advanced stages of AD pathology.”

The researchers are forthcoming about limitations of this study. Given it is rare for old-aged individuals not to have neurological deficits, AD or other neuropathological changes, their main limitation was that each of the four groups included merely four individuals. Despite limitations, these findings contribute to our understanding of brain aging in the absence of AD pathology and age-related neuropathological changes. 

The study revealed that major changes in protein expression were primarily associated with neuronal cell populations and became more pronounced with age. The preservation of specific protein pathways, proteasome components, autophagy-related components, and mitochondrial markers in advanced aging individuals without neurodegenerative disorders suggests the presence of resilience mechanisms that protect against protein dysregulation and neurodegeneration. Overall, this research provides valuable insights into the proteomic characteristics of healthy brain aging and highlights potential targets for therapeutic interventions aimed at promoting healthy brain aging and preventing age-related neurodegenerative diseases. Further studies are necessary to elucidate the specific mechanisms underlying these proteomic alterations and their functional implications in brain aging.

“The present observations identify proteostatic changes, including different changes in the phosphoproteome in the human FC in brain aging in the rare subpopulation of old-aged individuals without neurological deficits, and not having ADNC and other neuropathological change in any region of the telencephalon.”

Click here to read the full research paper published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

Click here to subscribe to Aging publication updates.

For media inquiries, please contact media@impactjournals.com.

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The Brain Age Gap

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The Trending With Impact series highlights Aging publications (listed by MEDLINE/PubMed as “Aging (Albany NY)” and “Aging-US” by Web of Science) 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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Listen to an audio version of this article

Aging is a risk factor for many diseases, including Alzheimer’s disease (AD). While scientists have made some progress in understanding the physiology of aging and its relationship to AD and related disorders, our understanding remains incomplete (to say the least). It is possible that civilization is currently in the midst of an artificial intelligence (AI) and machine learning (ML) “boom.” Researchers are now using AI and ML technologies to elevate our comprehension of aging and aging-related diseases.

“Artificial intelligence (AI) and machine learning (ML) technologies can help us better understand these diseases and aging itself by using biological data from the brain or other sources to create a mapping between age and biological data.”

In a new editorial paper, researchers Jeyeon Lee, Leland R. Barnard and David T. Jones from the Mayo Clinic in Rochester, Minnesota, discuss a recent study they conducted and explore the potential of AI to revolutionize the field of geriatrics. Their editorial was published in Aging’s Volume 15, Issue 8, on April 3, 2023, entitled, “Artificial intelligence and the aging mind.”

Their Study

In a recent 2022 study, Lee, Barnard, Jones, and the rest of their team developed convolutional neural network-based brain age prediction models using a large collection of data from brain magnetic resonance imaging (MRI) and brain fluorodeoxyglucose positron-emission tomography (FDG-PET) in people aged from 26 to 98 years old. In a sample of cognitively normal individuals, the AI models showed accurate brain age estimation of which a mean absolute error (MAE; unit, years) was 3.08±0.14 for the FDG-based model and 3.49±0.16 for the MRI-based model. 

The team found that higher brain age gaps (the difference between biological age and chronological age) were estimated in cohorts with neurodegenerative disorders—including mild cognitive impairment (MCI), AD, frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB)—than normal controls. The brain age gap was strongly associated with pathologic tau protein levels and cognitive test scores. This gap also showed longitudinal predictive ability for cognitive decline in AD-related disorders.

“Interestingly, the brain imaging patterns generating brain age gaps in AD showed higher similarity with normal aging than other neurodegenerative syndromes implying that AD might be more like an accelerated representation of biological aging than others.”

Summary & Conclusions

The study conducted by Lee, Barnard, Jones, and their team using neural network-based brain age prediction models has shown promising results in accurately estimating brain age and identifying differences between normal aging and neurodegenerative disorders. However, the authors of this editorial note that variations in data make creating a uniform language used to compare and contrast large sums of data very difficult.

“Although more research and optimization are needed to determine its clinical usefulness, the study of brain age has great potential as a tool for understanding brain aging and age-related diseases.”

In conclusion, aging is a complex process that increases the risk of Alzheimer’s disease and various diseases. Recent advancements in artificial intelligence and machine learning technologies offer new opportunities to better understand the underlying mechanisms of aging and aging-related disorders. This research opens up exciting possibilities for the future of geriatric care and improving the lives of aging populations. As technology continues to advance, it is likely that we will gain further insights into aging through the brain age gap, ultimately leading to better prevention, diagnosis and treatment options.

“The fact that the brain age gap is a comprehensive and intuitive measure of disease severity using biological data that is already being acquired in clinical practice, makes it an attractive biomarker for further development for clinical use [8].”

Click here to read the full editorial paper published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

Click here to subscribe to Aging publication updates.

For media inquiries, please contact media@impactjournals.com.

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RNA Virus Fruit Fly Model: First Study to Measure Single-Fly Respiration

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In a new study, researchers investigated the mortality and respiration rates of RNA virus-infected male fruit flies and how aging impacts these outcomes and measurements.

RNA Virus Fruit Fly Model: First Study to Measure Single-Fly Respiration

RNA viruses are responsible for approximately 70% of emerging infectious diseases in humans, according to a 2020 report by the National Academy of Medicine. Examples of RNA viruses include: influenza, hepatitis C, HIV, measles, zika, ebola, poliovirus, rhinovirus, rabies, and SARS-CoV-2—the virus responsible for the COVID-19 pandemic. After infection with an RNA virus, significant changes can take place in the host’s metabolism. While it is clear that disease tolerance declines as humans age, it is not yet clear how aging affects virus-induced changes in metabolism.

“Virus-induced metabolic reprogramming could impact infection outcomes, however, how this is affected by aging and impacts organismal survival remains poorly understood.”

In a new study, researchers Eli Hagedorn, Dean Bunnell, Beate Henschel, Daniel L. Smith Jr., Stephanie Dickinson, Andrew W. Brown, Maria De Luca, Ashley N. Turner, and Stanislava Chtarbanova from the University of Alabama, Indiana University, University of Arkansas for Medical Sciences, Arkansas Children’s Research Institute, and Jacksonville State University examined how an RNA virus can affect the respiration rate in male fruit flies (Drosophila melanogaster), both young and old. On March 22, 2023, their research paper was published in Aging’s Volume 15, Issue 6, entitled, “RNA virus-mediated changes in organismal oxygen consumption rate in young and old Drosophila melanogaster males.”

The Study

An organism’s metabolism depends on oxygen to produce energy. An efficient immune system depends, in part, on energy from the body’s metabolism to fuel it. Paradoxically, decreased metabolism, or hypometabolism, is a survival strategy that promotes disease tolerance in response to infection. In this study, the researchers used oxygen consumption rate (OCR) to indirectly measure changes in metabolism before and after RNA viral infection. The team infected male fruit flies with the RNA virus Flock House virus (FHV), and documented their oxygen consumption rate and/or mortality times at different time intervals after infection.

“As the exact mechanisms by which hypometabolism promotes tolerance are not fully understood, D. melanogaster could serve as an excellent model to dissect the genetic and molecular bases of this process.”

After the first 72-hours post-infection, FHV appeared to modulate respiration in all flies, but age did not appear to have a significant effect on OCR. However, over the course of the three-day experiment, the longitudinal assessment showed that OCR in young flies progressively and significantly decreased, while OCR in aged flies remained constant. The researchers found that the OCR at 24-hours varied in response to both experimental treatment and survival status. FHV-injected flies that died prior to 48- or 72-hours had a lower OCR compared to survivors at 48-hours. 

“Our results show that FHV infection significantly reduces organismal OCR compared to Tris-injected controls; however, we did not observe a significant change in OCR with aging. Interestingly, flies that died prior to 48-hours post-treatment measurements exhibited a significantly lower OCR at 24 h post-treatment compared to survivors. These findings suggest that the host’s metabolic profile could influence the outcome of viral infections.”

Conclusion

In conclusion, RNA viruses pose a significant threat to human health, causing numerous emerging infectious diseases. The impact of these viruses on the host’s metabolism, particularly in relation to aging, remains poorly understood. The recent study by Hagedorn et al. sheds light on the interaction between RNA viruses, metabolism and aging by examining the effects of the Flock House virus on the respiration rate of male fruit flies. The findings suggest that this infection can modulate the host’s OCR, and that the metabolic profile of the host could influence the outcome of viral infections.  The authors suggest that further research is needed to determine the precise mechanisms by which RNA viruses affect metabolic rate and to explore the potential for interventions to modulate metabolic rate and improve healthspan and lifespan.

“Older flies exhibit impaired disease tolerance to FHV [19], and here we show that metabolic rate depression does not occur in older flies in response to FHV in the first three days following treatment. It is therefore possible that as is the case in mammals, flies employ hypometabolism as a survival strategy that is part of a disease tolerance mechanism. It would be interesting in the future to test this hypothesis by comparing OCR in tolerance mutant flies such as the G9a mutants.”

Click here to read the full research paper published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

Click here to subscribe to Aging publication updates.

For media inquiries, please contact media@impactjournals.com.

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A Promising Approach to Preventing Periodontitis

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A new study by researchers from Osaka University’s Graduate School of Dentistry investigated cellular senescence in periodontal tissue and disease—identifying promising therapeutic targets for preventing periodontitis in the elderly.

A new study by researchers from Osaka University’s Graduate School of Dentistry investigated cellular senescence in periodontal tissue and disease—identifying promising therapeutic targets for preventing periodontitis in the elderly.

The Trending With Impact series highlights Aging publications (listed by MEDLINE/PubMed as “Aging (Albany NY)” and “Aging-US” by Web of Science) 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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Listen to an audio version of this article

Repercussions of poor dental health aren’t limited to mere social stigmas. Poor dental health can impart serious consequences on an individual’s overall health. Periodontal disease broadly refers to any disease that affects the gums and the surrounding tissues that support the teeth, including the periodontal ligament (PDL) and alveolar bone. Periodontal disease can increase the risk of heart disease, stroke and diabetes by allowing bacteria to enter the bloodstream, causing inflammation and organ damage. 

Periodontitis is a more advanced stage of periodontal disease. It is thought to be the most common infectious disease in the United States—affecting more than 40% of adults over 30 years old. Previous research has suggested that aging is a significant risk factor for periodontitis, although the underlying mechanisms are unclear.

“The direct cause of periodontitis is periodontopathic bacteria, while various environmental factors affect the severity of periodontitis. Previous epidemiological studies have shown positive correlations between aging and periodontitis. However, whether and how aging is linked to periodontal health and disease in biological processes is poorly understood.”

In a recent study, researchers Kuniko Ikegami, Motozo Yamashita, Mio Suzuki, Tomomi Nakamura, Koki Hashimoto, Jirouta Kitagaki, Manabu Yanagita, Masahiro Kitamura, and Shinya Murakami from Osaka University’s Graduate School of Dentistry aimed to elucidate the underlying mechanisms that contribute to aging-associated inflammation in periodontitis. On March 1, 2023, their new research paper was published in Aging (Aging-US) Volume 15, Issue 5, entitled, “Cellular senescence with SASP in periodontal ligament cells triggers inflammation in aging periodontal tissue.”

The Study

“In this study, we aimed to clarify the pathophysiological roles of cellular senescence in periodontal tissue and diseases.”

Previous studies have found that senescent cells can secrete senescence-associated secretory proteins (SASP) that induce inflammation and impair wound healing in some chronic diseases. The existence of senescent cells in periodontal tissue and diseases, however, has yet to be clarified. In this study, the researchers investigated cellular senescence and SASP in aging periodontal tissue. The team aimed to uncover the mechanism by which cellular senescence and SASP trigger inflammation in periodontal tissue and to identify potential therapeutic targets for this disease. 

To investigate the role of cellular senescence in periodontitis, the researchers analyzed periodontal tissue in young and aged mice. Alveolar bone volume was compared in the young and aged mice, and beta-galactosidase (β-gal) staining was performed. They found bone resorption in aged mice and many senescence-associated (SA) β-gal-positive cells in their periodontal tissue, leading to inflammation and breakdown of alveolar bone. Very few SA β-gal-positive cells were found in young mouse tissues.

Next, the researchers worked with cells in vitro, primary human periodontal ligament (HPDL) cells, and induced cellular senescence through serial passaging (replicative senescence). The growth rate of HPDL cells gradually reduced, and they reached irreversible cell growth arrest, indicating the induction of cellular senescence. Morphological changes were observed through phalloidin staining. The team found that around 70% of aged HPDL cells were positive for SA β-gal, while less than 10% of young HPDL cells were positive. Morphological changes showed that aged HPDL cells had an enlarged and “spread” cell shape compared to young HPDL cells. Flow cytometry analysis confirmed an increase in cell size and granularity of aged HPDL cells compared to young HPDL cells.

TEM analysis showed that senescent cells exhibit metabolic changes and irregularly shaped mitochondria with disrupted cristae and increased accumulation of ROS, which suggest damage and failure of the redox balance. Importantly, the researchers found that the intrinsic inflammation state of aged PDLs was higher than in young PDLs, and susceptibility to bactericidal pathogens (but not inflammatory cytokines) was low in aged PDLs. Additionally, the team observed an age-dependent upregulation of microRNA (miR)-34a in HPDL cells.

“Thus, miR-34a and senescent PDL cells might be promising therapeutic targets for periodontitis in elderly people.”

Summary & Conclusion

In conclusion, poor dental health can have serious implications on an individual’s overall health, as periodontal disease can increase the risk of heart disease, stroke and diabetes. Aging is a significant risk factor for periodontitis, which is thought to be the most common infectious disease in the United States. A recent study by researchers from Osaka University’s Graduate School of Dentistry aimed to elucidate the underlying mechanisms that contribute to aging-associated inflammation in periodontitis. The study found that senescent cells in periodontal tissue secrete SASP that induce inflammation. The researchers identified potential therapeutic targets for periodontitis and suggest that elimination of senescent PDL cells or suppression of the miR-34a-dependent SIRT1-NF-κB axis may be an attractive therapeutic strategy to prevent periodontitis in humans as we age.

“To the best of our knowledge, this is the first study to identify: 1) the potential for senescent PDL cells to induce inflammation of periodontal tissue, and 2) a miRNA-dependent molecular mechanism of SASP in senescent PDL cells.”

Click here to read the full research paper published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

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Fruit Flies Shed New Light on Memory and Aging

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In a recent study, researchers from Western University and Indiana University investigated the connection between aging, memory and lactate metabolism in flies.

Fruit Flies Shed New Light on Memory and Aging
Male common fruit fly (Drosophila Melanogaster) doing what fruit flies do best – enjoing its fruit (apple)

The Trending With Impact series highlights Aging publications (listed by MEDLINE/PubMed as “Aging (Albany NY)” and “Aging-US” by Web of Science) 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 brain is a complex organ responsible for many critical functions, including the formation and retrieval of our memories. As we age, the brain undergoes changes that can affect cognitive abilities, including our memory. Understanding the mechanisms that underlie these changes is critical for developing therapies for age-related cognitive decline. 

“Over the last two decades there has been growing recognition that lactate, the end product of glycolysis, serves many functions, including acting as a source of energy, a signaling molecule, and even as an epigenetic regulator.”

Lactate & LDH

Lactate is a molecule that is produced during the metabolism of glucose in the body. It is a byproduct of anaerobic metabolism, which occurs when there is insufficient oxygen supply to meet the energy demands of the body. Lactate can be used as an energy source by some cells, such as the heart and skeletal muscles, and it can also be transported to the liver where it can be converted back into glucose.

Lactate dehydrogenase (LDH), on the other hand, is an enzyme that catalyzes the conversion of pyruvate to lactate (the reverse reaction of lactate production) and is also involved in other metabolic processes. This enzyme is found in many tissues of the body, including the heart, liver and skeletal muscles, and is released into the bloodstream when tissues are damaged. LDH is often used as a diagnostic marker for various medical conditions, such as heart attacks, liver disease and certain cancers. High levels of LDH in the blood may indicate tissue damage or cell death, while low levels may indicate a deficiency in the enzyme.

The Study

Recently, researchers investigated the role of LDH in memory formation and aging using Drosophila melanogaster (fruit flies) as a model organism. In a new study, researchers Ariel K. Frame, J. Wesley Robinson, Nader H. Mahmoudzadeh, Jason M. Tennessen, Anne F. Simon, and Robert C. Cumming from Western University and Indiana University used genetic manipulation techniques to alter LDH expression in the neurons or glia of fruit flies to investigate its effects on aging and memory. Their research paper was published in Aging’s Volume 15, Issue 4, and entitled, “Aging and memory are altered by genetically manipulating lactate dehydrogenase in the neurons or glia of flies.”

“The astrocyte-neuron lactate shuttle hypothesis posits that glial-generated lactate is transported to neurons to fuel metabolic processes required for long-term memory.”

Lactate shuttling is a process in which lactate is transported from one cell or tissue to another for use as an energy source or as a signaling molecule. Previous research has shown that LDH is expressed in both neurons and glia in the brain, and that it may play a role in regulating synaptic plasticity and memory formation. The authors of the current research paper aimed to test the hypothesis that alterations in LDH expression in the brain may contribute to age-related cognitive decline.

“D. melanogaster serves as a good model for understanding the role of glia-neuron lactate shuttling in central nervous system (CNS) function and cognitive behaviour.”

To test this hypothesis, the researchers genetically manipulated LDH expression in the neurons or glia of fruit flies (dLDH) and assessed the impact on memory formation and aging. Specifically, they used RNA interference (RNAi) to either knock down or overexpress dLDH in either neurons or glia. They then assessed the effects of these manipulations on two different memory tasks at different ages, courtship memory and aversive olfactory memory, and also assessed survival, negative geotaxis, brain neutral lipids (the core component of lipid droplets), and brain metabolites.

Results

Their results showed that dLDH manipulation had differential effects on fruit flies depending on the cell type in which it was altered. In neurons, both upregulation and downregulation of dLDH resulted in memory impairment and decreased survival with age. In contrast, downregulation of dLDH in glial cells caused age-related memory impairment, without altering survival. Upregulating dLDH expression in glial cells lowered survival without disrupting memory. Both neuronal and glial dLDH upregulation increased neutral lipid accumulation.

“We provide evidence that altered lactate metabolism with age affects the tricarboxylic acid (TCA) cycle, 2-hydroxyglutarate (2HG), and neutral lipid accumulation.”

The results of this study may provide new insights into the role of LDH in memory formation and aging in humans. The findings suggest that LDH may be a potential target for developing therapies to combat age-related cognitive decline. Additionally, the study highlights the importance of considering cell-type specificity when investigating the role of genes and enzymes in complex biological processes. A limitation of the study is that it was conducted in fruit flies, which may not fully capture the complexity of memory formation and aging in humans. However, fruit flies have been shown to be a valuable model organism for studying many aspects of brain function, and the findings of this study may provide a foundation for future research in mammals.

“Collectively, our findings indicate that the direct alteration of lactate metabolism in either glia or neurons affects memory and survival but only in an age-dependent manner.”

Conclusion

In conclusion, the study provides new insights into the role of LDH in memory formation and aging. The findings suggest that LDH may play a critical role in regulating energy metabolism in the brain, which in turn affects synaptic plasticity and memory formation. The study also highlights the importance of considering cell-type specificity when investigating the role of genes and enzymes in complex biological processes. Future research in mammals may be needed to further explore the implications of these findings for human health and the potential for developing therapies for age-related cognitive decline. Nonetheless, this study provides an important step forward in understanding the complex interplay between lactate metabolism, memory and aging.

“In this study we demonstrate the importance of maintaining appropriate levels of dLdh in D. melanogaster glia and neurons for maintenance of long-term courtship memory and survival with age (Figure 6). In addition, our results implicate lipid metabolism, 2HG accumulation, and changes in TCA cycle activity as factors underlying the age-related impacts of perturbed dLdh expression, which likely modifies glia-neuron lactate shuttling in the fly brain.”

Click here to read the full research paper published by Aging.

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Aging is an open-access, peer-reviewed journal that has been publishing high-impact papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

For media inquiries, please contact media@impactjournals.com.

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The Role of Lipids in Aging: Insights From C. Elegans

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In a new study, researchers used C. elegans to investigate how changes in lipids during aging might impact lifespan and healthspan.

The Role of Lipids in Aging: Insights From C. Elegans

The Trending With Impact series highlights Aging publications (listed as “Aging (Albany NY)” by Medline/PubMed and “Aging-US” by Web of Science) 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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Lipids are a diverse group of biomolecules that are essential for life, including fats, oils, waxes, and steroids, and play crucial roles in cell membrane structure, energy storage and signaling. Lipidomics is the comprehensive analysis of lipids and their interactions in biological systems, with an aim to understand the role of lipids in cellular processes and their association with diseases. As we age, our cells undergo complex changes, including alterations in cellular lipid profiles. These changes are not only confined to humans; organisms such as the nematode Caenorhabditis elegans (C. elegans) are also subject to changes in lipid composition during aging. 

“For example, lipid classes including fatty acids (FA), triacylglycerols (TAG), sphingolipids (SL), and phospholipids (PL) have been identified as targets in lipid signatures related to aging [2, 3]. Furthermore, specific signatures are detected in the lipid profiles of those with age-related diseases, such as Alzheimer’s Disease [4–9]. In addition, the abundance of many fatty acid subtypes differs between the youth, elderly, and centenarians [10, 11].”

In a recent study, researchers Trisha A. Staab, Grace McIntyre, Lu Wang, Joycelyn Radeny, Lisa Bettcher, Melissa Guillen, Margaret P. Peck, Azia P. Kalil, Samantha P. Bromley, Daniel Raftery, and Jason P. Chan from Marian University, the University of Washington and Juniata College investigate the lipid profiles of C. elegans with mutations in the genes asm-3/acid sphingomyelinase and hyl-2/ceramide synthase during aging. On February 13, 2023, their research paper was published in Aging’s Volume 15, Issue 3, entitled, “The lipidomes of C. elegans with mutations in asm-3/acid sphingomyelinase and hyl-2/ceramide synthase show distinct lipid profiles during aging.”

The Study

In this study, the researchers focused on two enzymes that are important in the production of ceramides—a type of lipid that is known to play a role in various cellular processes, including cell signaling and apoptosis. The enzymes, acid sphingomyelinase 3 (asm-3) and ceramide synthase (Hyl-2), are involved in the breakdown of sphingomyelin and the synthesis of ceramide, respectively. The team compared C. elegans with mutations in these specific genes with wild type C. elegans at one-, five- and 10-days of age to investigate how changes in these enzymes affect lipid profiles during aging.

“In particular, work using C. elegans have identified age related changes in specific lipids, lipid classes, as well as the ratio of monosaturated to polysaturated fatty acids (MUFA:PUFA ratio) [36, 37]. Here, we examine the lipidomes of animals lacking the sphingolipid metabolism enzymes, asm-3/acid sphingomyelinase or hyl-2/ceramide synthase, which have previously been shown to have extended and reduced lifespans, respectively, in C. elegans [24, 34, 38].”

The results showed that the asm-3 mutant worms had higher levels of sphingomyelin and lower levels of ceramides compared to wild-type worms. In contrast, the hyl-2 mutant worms had lower levels of sphingomyelin and higher levels of ceramides. These findings suggest that asm-3 and Hyl-2 have opposite effects on the production of ceramides in C. elegans. The researchers also found that the lipid profiles of the mutant worms changed with age, with a decrease in sphingomyelin and an increase in ceramides in the asm-3 mutant worms and, in the hyl-2 mutant worms, there was an increase in sphingomyelin and a decrease in ceramides with age.

The researchers also investigated the effects of these lipid profile changes on lifespan and healthspan. They found that the asm-3 mutant worms had a shorter lifespan and reduced healthspan compared to wild-type worms. In contrast, the hyl-2 mutant worms had an extended lifespan and improved healthspan. These findings suggest that changes in lipid profiles can have significant effects on lifespan and healthspan in C. elegans.

Conclusions

Overall, this study sheds light on the complex role of lipids in aging and highlights the importance of ceramides in cellular processes. The findings suggest that changes in the production of ceramides, mediated by asm-3 and Hyl-2, can have significant effects on lifespan and healthspan in C. elegans. Further research in this area could lead to the development of interventions that target ceramide production to promote healthy aging in humans.

There are several potential implications of this study for human health. First, the findings suggest that interventions aimed at modulating ceramide production could have significant effects on aging-related diseases. Ceramide has been implicated in various diseases, including cancer, Alzheimer’s disease and diabetes. Targeting ceramide production could be a promising strategy for the prevention and treatment of these diseases.

Second, the study highlights the importance of understanding the complex interplay between lipids and cellular processes in aging. Aging is a complex process that involves multiple cellular and molecular changes, and alterations in lipid metabolism are just one aspect of this process. A better understanding of the role of lipids in aging could lead to the development of new interventions that target multiple aspects of the aging process.

Finally, the study underscores the importance of using model organisms, such as C. elegans, to investigate the molecular mechanisms of aging. While C. elegans is a simple organism, it shares many fundamental biological processes with humans, and its short lifespan makes it an ideal model for aging research. The findings from this study could be applied to future research in humans, as well as other model organisms, and could lead to the development of novel interventions for aging-related diseases.

“Age caused increased sphingomyelin levels, particularly in short-lived animals. This may suggest that the regulation of sphingolipid metabolism may mediate changes in cell structure and function important for healthy aging. Future studies connecting lipidomic changes in sphingolipid metabolism mutants to mechanistic changes in cells of mutant models will be important next steps to better understanding the roles of sphingolipids in aging.”

Click here to read the full research paper published by Aging.

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

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Aging is an open-access, peer-reviewed journal that has published high-impact research papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

For media inquiries, please contact media@impactjournals.com.

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BMI Correlates With Accelerated Epigenetic Aging in Young Adults

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In a recent study, researchers from the University of Alabama at Birmingham’s Department of Pediatrics examined the relationship between measures of obesity and DNA methylation in young adults.

BMI Correlates With Accelerated Epigenetic Aging in Young Adults

The Trending With Impact series highlights Aging publications (listed as “Aging (Albany NY)” by Medline/PubMed and “Aging-US” by Web of Science) 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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While the study of genetics focuses on heredity and alterations in the genetic code itself, epigenetics refers to the changes in gene expression that occur as a result of environmental or lifestyle factors. Advances in epigenetic research have allowed measures of DNA methylation (DNAm) (epigenetic clocks) to illustrate clear links between obesity, accelerated epigenetic aging and a variety of negative health outcomes in older adults. Despite these advances, there is a lack of research about these correlations and sex-based variations among young adults. The ability to detect accelerated epigenetic aging in young adulthood could potentially be used to prevent the onset of chronic diseases and improve health outcomes later in life.

“Moreover, few studies have included replication across measures of obesity and epigenetic aging to examine the robustness or specificity of these effects. Finally, little is known about sex differences in the links between obesity and epigenetic aging, despite evidence of substantial sex dimorphism in both physiological and epigenetic aging [20].”

In a recent study, researchers Christy Anne Foster, Malcolm Barker-Kamps, Marlon Goering, Amit Patki, Hemant K. Tiwari, and Sylvie Mrug from the University of Alabama at Birmingham’s Department of Pediatrics examined the relationship between obesity and measures of DNAm in young adults. They also investigated whether there is a sex-dependant correlation between obesity and DNAm in young adults. On January 18, 2023, their research paper was published in Aging’s Volume 15, Issue 2, and entitled, “Epigenetic age acceleration correlates with BMI in young adults.”

Research and Results

Here, the researchers explored the relationship between measures of obesity and epigenetic age acceleration in young adults. The team included a cross-sectional community sample of 290 healthy young adults—with 60% being female, 80% African American, 18% White, and a total mean age of 27 years old. The researchers measured participant BMI and waist circumference, and also calculated their epigenetic age acceleration using four epigenetic age estimators (derived from salivary DNA): Hannum DNAm, Horvath DNAm, Phenoage DNAm, and GrimAge DNAm. In addition, they collected data on covariates, including age, sex, race, parental education, and income-to-needs ratio.

After covariates were adjusted for, the researchers found that DNAm PhenoAge was higher in participants who had higher body mass index (BMI) and waist circumference in both sexes, with a stronger effect on BMI in males compared to females. Horvath DNA methylation age was associated with participants who had larger waist circumferences, but not BMI. Higher Hannum DNAm age was associated with both higher BMI and waist circumference in men, but not in women. In this study, GrimAge was not associated with either BMI or waist circumference. As a whole, none of the associations with the DNAm indicators varied by race. The researchers found that scoring higher on one or more of the four DNAm indicators was associated with an older chronological age, lower socioeconomic status, being female and White, as well as saliva cell composition. 

“Together, these results suggest that higher BMI and waist circumference are associated with higher epigenetic age in young adulthood. Because the analyses adjusted for chronological age, associations with higher epigenetic age indicate faster epigenetic aging [22]. Importantly, this study demonstrated associations between obesity and epigenetic aging using DNA from saliva, which involves a non-invasive sample collection compared to other tissues (e.g., blood) and thus can be more readily translated into clinical practice, highlighting the usefulness in young adults.”

Significance and Limitations

These findings are significant because they suggest that body weight plays a role in determining epigenetic age acceleration, which in turn can affect overall health and lifespan. Previous research has shown that epigenetic age acceleration is associated with increased risk for age-related diseases such as cardiovascular disease, type 2 diabetes and certain cancers. However, it is important to note that this study only shows a correlation between BMI and epigenetic age acceleration and does not provide evidence of causality. It is possible that other factors, such as diet, exercise and stress levels, could also contribute to the relationship between BMI and epigenetic age acceleration.

The authors were forthcoming about several study limitations in their research paper, including a relatively small sample size which limited statistical power and precluded rigorous analysis of individual CpG sites. The original sample was locally representative but experienced some differential attrition over time, which could limit generalizability to certain populations. Epigenetic clocks have been tested primarily in White populations and may be less relevant to African American individuals who comprised the majority of this sample. This study used salivary DNA, so replication using DNA extracted from other tissues will be important for future work. The cross-sectional design did not allow testing directional effects between BMI and epigenetic aging over time. None of the CpGs used in calculating methylation age were part of known causal effect on BMI as per Mendelian Randomization studies; further modeling with outcomes from other tissues impacted by obesity may provide more insight into methylation aging process.

Conclusions

In conclusion, this study sheds light on the relationship between BMI and epigenetic age acceleration in young adults. The results suggest that young adults with higher BMIs may be aging faster and at a higher risk for age-related diseases. These findings highlight the importance of maintaining a healthy weight and lifestyle, not only for weight management but also for overall health and lifespan.

In the context of the growing obesity epidemic and the increasing focus on personalized medicine and preventive health, this study provides valuable insights into the potential health impacts of body weight and the role of epigenetics in health and disease. Further research is needed to fully understand the mechanisms behind this relationship and to determine the best approaches for improving health and lifespan in young adults.

“In conclusion, this study extends prior research by demonstrating the association between obesity and salivary epigenetic aging in young adult males and females. These findings are of interest to those who are interested in epigenetic age acceleration as a potential biomarker. They also support future research examining obesity as a causal risk factor for epigenetic age acceleration. The findings underscore the importance of testing sex differences and including multiple epigenetic clocks in future research. Overall, the present results add to mounting evidence that obesity affects cellular aging across multiple tissues early in the lifespan.”

Click here to read the full research paper published by Aging.

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

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Aging is an open-access, peer-reviewed journal that has published high-impact research papers in all fields of aging research since 2009. These papers are available to readers (at no cost and free of subscription barriers) in bi-monthly issues at Aging-US.com.

For media inquiries, please contact media@impactjournals.com.

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