“As advanced age is associated with increased incidence of hypoxia-associated conditions such as asthma, emphysema, ischemic heart disease, heart failure, and apnea, our findings have important implications for many people.”
As we age, our brains become more sensitive to stress and disease. A recent study sheds light on a lesser-known risk: reduced oxygen levels. The study, titled “Defining the hypoxic thresholds that trigger blood-brain barrier disruption: the effect of age” and recently published as the cover for Volume 17, Issue 5 of Aging (Aging-US), found that low oxygen—also called hypoxia—can harm the aging brain by disrupting the blood-brain barrier (BBB). This damage may contribute to cognitive decline, memory problems, and an increased risk of dementia.
Understanding Hypoxia in the Brain
The brain relies on a steady supply of oxygen to stay healthy. When oxygen levels fall—a condition known as hypoxia—the brain undergoes changes to adapt. These changes include the remodeling of blood vessels and, importantly, a weakening of the blood-brain barrier. The BBB acts as a filter, protecting brain tissue from harmful substances. When it breaks down, it can lead to inflammation, brain cell damage, and cognitive issues.
Hypoxia is common in older adults, especially those with conditions like sleep apnea, chronic obstructive pulmonary disease (COPD), heart failure, and asthma. That is why understanding the connection between low oxygen and the aging brain is crucial for preventing long-term neurological damage.
The Study: Exploring Brain Vulnerability to Hypoxia
To investigate how age affects the brain’s response to low oxygen, researchers at the San Diego Biomedical Research Institute studied young and old mice. They exposed the mice to different levels of oxygen—from normal (21%) down to 8%—to see at what point the BBB begins to fail. The study by Arjun Sapkota, Sebok K. Halder, Richard Milner, also tracked how sensitivity to hypoxia changes across the lifespan, examining mice from 2 to 23 months old.
The Results: Low Oxygen Damages the Blood-Brain Barrier in Older Brains
The results showed that older mice experienced blood-brain barrier disruption at higher oxygen levels—around 15%—compared to younger mice, which only showed damage at more severe hypoxia (13%). The damage in aged mice was also more severe: their BBB was four to six times leakier than in young mice under the same conditions.
Interestingly, the increased brain vulnerability began earlier than expected. Mice showed greater sensitivity to hypoxia between the ages of 2 and 6 months and again between 12 and 15 months. Additionally, microglia—immune cells in the brain—were more reactive in older mice, even at mild oxygen reductions. This suggests that as we age, the brain becomes not only more sensitive to hypoxia but also more prone to inflammation.
The Breakthrough: Understanding the Link Between Hypoxia and Cognitive Decline
This study is the first to clearly define how the threshold for oxygen-related brain damage changes with age. In simple terms, oxygen levels that are safe for young individuals can harm older adults. This discovery helps explain why conditions like sleep apnea, which reduce oxygen during sleep, are linked to higher dementia risk in older populations.
The Impact: A New Approach to Brain Health in Aging Populations
For older adults, keeping oxygen levels within a healthy range could be essential to protecting brain function. The study also has practical implications for people traveling to high altitudes. Oxygen levels similar to 15%, which were enough to cause BBB damage in aged mice, are found at elevations around 8,600 feet.
These findings highlight the importance of monitoring oxygen exposure, especially for those with chronic illnesses. Strategies to strengthen the blood-brain barrier may help reduce the risk of hypoxia-induced cognitive decline in aging individuals.
Future Perspectives and Conclusion
The aging brain is more vulnerable to low oxygen than previously believed. Even mild reductions in oxygen can lead to blood-brain barrier disruption, brain inflammation, and cognitive problems. This study offers valuable insights that can help guide future treatments aimed at protecting the brain in older adults.
For anyone living with respiratory or heart conditions, this research delivers an important message. Preventing hypoxia is just as crucial as treating illness. Monitoring and managing oxygen levels may not only extend lifespan but also help ensure better brain health and quality of life as we age.
Click here to read the full research paper in Aging.
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Aging is indexed by PubMed/Medline (abbreviated as “Aging (Albany NY)”), PubMed Central, Web of Science: Science Citation Index Expanded (abbreviated as “Aging‐US” and listed in the Cell Biology and Geriatrics & Gerontology categories), Scopus (abbreviated as “Aging” and listed in the Cell Biology and Aging categories), Biological Abstracts, BIOSIS Previews, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science).
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“Werner syndrome (WS), caused by mutations in the RecQ helicase WERNER (WRN) gene, is a classical accelerated aging disease with patients suffering from several metabolic dysfunctions without a cure.”
Werner syndrome is a rare condition marked by accelerated aging. A recent study, featured as the cover paper in Aging (Aging-US), Volume 17, Issue 4, led by researchers at the University of Oslo and international collaborators, suggests that nicotinamide adenine dinucleotide (NAD+), a vital molecule involved in cellular energy production, may be key to understanding this disease and developing future strategies to manage it.
Understanding Werner Syndrome
Werner syndrome (WS) is a rare genetic condition that causes people to age more quickly than normal. By their 20s or 30s, individuals with WS often show signs typically associated with older age, such as cataracts, hair loss, thinning skin, and heart disease. This premature aging is caused by mutations in the WRN gene, which normally helps repair DNA and protect cells from damage. While the WRN gene’s role in maintaining genetic stability is well understood, the reasons behind the rapid decline of cells in WS patients are still not fully clear.
The research team, led by first author Sofie Lautrup and corresponding author Evandro F. Fang, used human stem and skin cells from WS patients, as well as gene-edited cells that mimic WS by lacking the WRN gene. These were always compared to control cells isolated from healthy individuals.
The researchers tracked how WRN deficiency affected NAD+ levels in mitochondria, the parts of the cell that generate energy. They then tested whether boosting NAD+ using a compound called nicotinamide riboside (NR)—a form of vitamin B3—could help restore normal cellular function. The team also used other strategies to raise mitochondrial NAD+ directly, including overexpressing a transporter protein known as SLC25A51. Their goal was to determine whether these approaches could reverse aging-related damage and restore cell growth affected by WRN mutations.
The Results: NAD+ Can Reduce Aging Signs The findings confirmed that WRN-deficient cells had lower levels of mitochondrial NAD+ and showed signs of cellular aging, such as increased senescence and reduced proliferation. Treating these cells with NR significantly reduced aging markers and restored some normal functions in both stem and skin cells from WS patients. In healthy control cells, NR had no such effect, suggesting it works specifically in the context of NAD+ deficiency.
However, increasing NAD+ either through NR supplementation or by enhancing mitochondrial transport was not enough to fully restore cell division in lab-grown cells lacking WRN. This result suggests that while NAD+ supplementation is beneficial, the WRN gene itself plays a unique and irreplaceable role in supporting healthy cell growth.
The Breakthrough: Linking Mitochondrial NAD+ to Cell Aging This study reveals a deeper role for the WRN gene beyond DNA repair. It shows that WRN also helps regulate how NAD+ is produced and used within cells, particularly in mitochondria. Without WRN, this system becomes unbalanced, accelerating cell aging. While boosting NAD+ helped reduce aging features in WS cells, the findings make clear that NAD+ therapy alone cannot replace the broader functions of WRN.
The Impact: A Step Toward Slowing Down Cellular Aging
This is the first study to directly show how low mitochondrial NAD+ contributes to premature aging in WS. Beyond its relevance to WS, the research highlights the broader potential of targeting NAD+ metabolism as a strategy for addressing age-related diseases. By increasing our understanding of how energy production affects aging, this study opens the door to future treatments aimed at promoting healthier aging across a wider population.
Future Perspectives and Conclusion This study offers promising new insights but also demonstrates the complexity of cellular aging. The WRN gene plays a much broader role than DNA repair alone. It appears to regulate networks of genes linked to metabolism and genome organization. While boosting NAD+ can reduce some signs of cellular damage, it cannot fully compensate for the loss of WRN function.
Looking ahead, further research will be crucial to understanding how NAD+ operates in different parts of the cell and how it might work in combination with other treatments. For individuals with Werner syndrome, and potentially for the wider aging population, these findings bring us closer to future therapies aimed at improving health and longevity.
Click here to read the full research paper in Aging.
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Aging is indexed by PubMed/Medline (abbreviated as “Aging (Albany NY)”), PubMed Central, Web of Science: Science Citation Index Expanded (abbreviated as “Aging‐US” and listed in the Cell Biology and Geriatrics & Gerontology categories), Scopus (abbreviated as “Aging” and listed in the Cell Biology and Aging categories), Biological Abstracts, BIOSIS Previews, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science).
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Alzheimer’s disease is a progressive neurological disorder that gradually steals memory, independence, and a person’s sense of identity. A defining feature of Alzheimer’s is the buildup of amyloid-β (Aβ) plaques—sticky protein clumps that interfere with communication between brain cells. This disruption is closely linked to changes in a group of enzymes called cholinesterases, especially acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These enzymes normally play a vital role in regulating neurotransmitters critical for memory, learning, and cognitive function. In Alzheimer’s, however, their behavior changes significantly, particularly when they interact with Aβ plaques.
The Study: Exploring Senolytics for Alzheimer’s Enzyme Inhibition
A research team from Dalhousie University in Canada looked into whether senolytic compounds—a class of drugs that eliminate damaged, aging cells often referred to as “zombie” cells—could also target the harmful forms of cholinesterase enzymes found in Alzheimer’s disease. Their goal was to see if these compounds could selectively inhibit the disease-associated versions of AChE and BChE, without affecting the healthy forms that are essential for normal brain function.
Led by Dr. Sultan Darvesh, the study tested six compounds: five senolytics—dasatinib, nintedanib, fisetin, quercetin, and GW2580—and one nootropic, meclofenoxate hydrochloride, known for its memory-enhancing potential. The researchers used post-mortem brain tissue from Alzheimer’s patients, enzyme activity assays, and computer modeling to examine how these compounds interact with the enzymes.
The Challenge: Targeting the Right Enzymes
One of the limitations of current Alzheimer’s treatments is that they do not distinguish between the normal and the altered forms of cholinesterases. While these drugs can raise levels of the memory-related chemical acetylcholine and improve cognitive function, they often come with side effects due to their broad activity. A more precise approach—targeting only the versions of AChE and BChE tied to Aβ plaques—could offer better outcomes with fewer drawbacks.
The Results: Senolytics Show Precision in Enzyme Targeting
The results were promising. Some of the senolytics tested, like dasatinib and nintedanib, effectively blocked the cholinesterases attached to Aβ plaques without affecting the normal versions of these enzymes in healthy brain tissue. Meclofenoxate also showed strong activity against the disease-associated forms. Interestingly, this selectivity was linked to how these compounds bind to the enzymes. Instead of locking onto the main active site, many of them attached to alternative regions, known as allosteric sites, which are only altered in the plaque-associated forms. This type of binding allowed the compounds to distinguish between harmful and healthy enzymes.
The Breakthrough: Targeting the Disease, Preserving the Brain
This study is the first to show that certain senolytic and cognitive-enhancing drugs can selectively inhibit the dysfunctional versions of cholinesterases found in Alzheimer’s without affecting their normal forms. This level of precision could mark a major step forward in Alzheimer’s therapy.
The Impact: A Dual-Action Path to Treating Alzheimer’s
By focusing on only the problematic forms of AChE and BChE, this approach could lead to Alzheimer’s treatments that better preserve cognitive function while avoiding side effects. The research also bridges two important areas of study: aging and neurodegeneration. It suggests that drugs developed to slow aging might also be used as targeted treatments for Alzheimer’s, offering a two-in-one therapeutic advantage.
Future Perspectives and Conclusion
Although more research is needed, especially in living models and clinical trials, the potential of the findings is encouraging. They lead the way for a new generation of Alzheimer’s treatments that are more targeted and safer.
By understanding better how aging and brain disease intersect at the cellular level, scientists may be moving closer to developing more effective and personalized approaches to combat Alzheimer’s.
Click here to read the full research paper in Aging.
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Aging is indexed by PubMed/Medline (abbreviated as “Aging (Albany NY)”), PubMed Central, Web of Science: Science Citation Index Expanded (abbreviated as “Aging‐US” and listed in the Cell Biology and Geriatrics & Gerontology categories), Scopus (abbreviated as “Aging” and listed in the Cell Biology and Aging categories), Biological Abstracts, BIOSIS Previews, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science).
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“These insights underscore the importance of personalized treatment approaches and the need for further research to improve radiotherapy outcomes in cancer patients.”
Radiation therapy or radiotherapy, is a common treatment for cancer, but its effectiveness differs across patients. A recent study published as the cover for Volume 17, Issue 2of Aging explored why this happens. The findings provide valuable insights, particularly for brain cancers like glioblastoma (GBM) and low-grade gliomas (LGG).
Understanding Glioblastoma and Low-Grade Gliomas
Glioblastoma and LGG are both brain tumors, but they behave in very different ways. GBM is highly aggressive, with most patients surviving only 12 to 18 months, even with surgery, chemotherapy, and radiation therapy. LGG, on the other hand, grows more slowly, and many patients live for decades with proper care.
The Study: Investigating Radiation Therapy’s Impact on Cancer Patients Survival
A research team led by first author Alexander Veviorskiy from Insilico Medicine AI Limited, Abu Dhabi, UAE, and corresponding author Morten Scheibye-Knudsen from the Center for Healthy Aging, University of Copenhagen, studied how radiation therapy affects cancer patient survival. They examined data from The Cancer Genome Atlas (TCGA), which includes 32 types of cancer. When they found that GBM and LGG had very different survival outcomes after radiation, they decided to focus on these two types of brain cancer. To learn more about their differences, gene expression and molecular pathways connected to radiation therapy responses were studied.
The Challenge: Why Radiation Therapy Works Only in Certain Tumors
Radiation therapy is an important cancer treatment, but its success is not the same for everyone. Even patients with the same type of cancer can respond differently, making it difficult to predict who will benefit. Understanding why some tumors are sensitive to radiation while others resist it is key to improving treatment and patient survival.
The Results: Radiation Therapy Works for Glioblastoma but Not for Low-Grade Gliomas
Overall, GBM had the highest percentage of patients receiving radiation therapy (82%), followed by LGG (54%). When researchers compared survival outcomes, they found that while radiation improved survival in breast cancer and GBM patients, it had a negative effect on patients with lung adenocarcinoma and LGG. This led researchers to take a closer look at GBM and LGG, especially since LGG can develop into GBM over time.
A key discovery was how GBM and LGG regulate DNA repair differently. GBM tumors have weak DNA repair activity, making them more vulnerable to radiation-induced damage. LGG tumors, however, activate more DNA repair pathways, allowing cancer cells to survive radiation and potentially making treatment less effective.
The immune response to radiation therapy was also different. In GBM, radiation triggered an immune response, which may help fight the tumor. In LGG, however, immune activation was significantly lower, meaning that radiation therapy did not enhance the body’s ability to attack cancer cells. This fact may contribute to worse survival outcomes for LGG patients after treatment.
Further genetic analysis revealed that ATRX gene mutations made GBM and LGG patients more sensitive to radiation. On the other hand, higher EGFR gene activity was linked to lower survival rates after radiation in LGG patients. Similar findings for GBM tumors indicate treatment resistance.
The Breakthrough: Toward Personalized Treatment
This study offers new insights into why radiation therapy benefits certain brain tumors while being less effective, particularly in GBM and LGG. Finding important biological factors, like DNA repair activity, immune response, and genetic changes that may serve as biomarkers, will help radiation therapy be more precisely tailored to each patient’s unique tumor profile.
The Impact: Rethinking Glioblastoma and Low-Grade Gliomas Treatment
These findings highlight the importance of precision medicine in brain cancer treatment. Instead of automatically recommending radiation therapy for all LGG patients, oncologists should consider genetic testing to determine whether this treatment will be beneficial or not. If not, alternative treatments may be necessary. Immunotherapy and targeted drugs against EGFR could provide better outcomes for patients who do not respond well to radiation therapy.
For GBM, researchers are investigating ways to enhance radiation’s effectiveness by combining it with DNA repair inhibitors, such as PARP inhibitors. These drugs could increase tumor sensitivity to radiation and improve survival rates.
Conclusion
Advancing cancer treatment requires a personalized approach. Identifying biomarkers that predict how GBM and LGG tumors respond to radiation therapy can help clinicians make more informed treatment decisions, ensuring that patients receive the most effective and least harmful therapies. By uncovering key genetic and molecular insights, this study moves the field closer to individualized brain cancer treatments, improving survival rates while reducing unnecessary risks for patients.
Click here to read the full research paper in Aging.
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Aging is indexed by PubMed/Medline (abbreviated as “Aging (Albany NY)”), PubMed Central, Web of Science: Science Citation Index Expanded (abbreviated as “Aging‐US” and listed in the Cell Biology and Geriatrics & Gerontology categories), Scopus (abbreviated as “Aging” and listed in the Cell Biology and Aging categories), Biological Abstracts, BIOSIS Previews, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science).
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Bone mass declines with age, and the anabolic effects of skeletal loading decrease. While much research has focused on gene transcription, how bone ages and loses its mechanoresponsiveness at the protein level remains unclear.
Researchers Christopher J. Chermside-Scabbo, John T. Shuster, Petra Erdmann-Gilmore, Eric Tycksen, Qiang Zhang, R. Reid Townsend, Matthew J. Silva from Washington University School of Medicine and Washington University in St. Louis, MO, share their findings which underscore the need for complementary protein-level assays in skeletal biology research.
In this study, the tibias of young-adult and old mice were analyzed using proteomics and RNA-seq techniques, while the femurs were examined for age-related changes in bone structure. A total of 1,903 proteins and 16,273 genes were detected through these analyses. Multidimensional scaling demonstrated a clear separation between the young-adult and old samples at both the protein and RNA levels. Furthermore, 93% of the detected proteins were also identifiable by RNA-seq, and the abundance of these shared targets showed a moderately positive correlation. Additionally, differential expression analysis revealed 183 age-related differentially expressed proteins and 2,290 differentially expressed genes between young-adult and old bone samples.
Proteomic and RNA-seq analyses were conducted on paired tibias from young-adult and old mice to study age-related differences and the effects of mechanical loading on bone formation. The results showed distinct differences in protein and gene expression between the two age groups. Many of the significantly upregulated and downregulated proteins and genes in old bone have been associated with bone phenotypes in genome-wide association studies (GWAS). The study also identified age-related differentially expressed proteins and genes involved in bone phenotypes and aging processes. Integrated analysis with GWAS data revealed eight targets that may be relevant to human disease, including Asrgl1 and Timp2. Furthermore, co-expression analysis identified an age-related module indicating baseline differences in TGF-beta and Wnt signaling. Baseline age-related differences in ECM/MMPs and TGF-beta signaling were detected in both the proteome and transcriptome. Following mechanical loading, the proteome showed distinct pathway, protein class, and process enrichments, with temporal differences observed between young-adult and old mice.
Overall, the findings provide valuable insights into the molecular mechanisms underlying age-related changes and the response to mechanical loading in mouse long bones.
DISCUSSION
This study aimed to compare the proteome and transcriptome of tibias from young-adult and old mice under baseline conditions and analyze changes in the bone proteome in response to mechanical loading. The researchers successfully developed a proteomics method to detect protein-level changes in cortical bone and used it to perform proteomic and RNA-seq analyses on tibias from both young-adult and old mice. They observed a moderately positive correlation between the proteome and transcriptome in bone tissue. Age-related differences were detected at both the protein and RNA levels, with altered TGF-beta signaling and changes in extracellular matrix (ECM) and matrix metalloproteinases (MMPs) protein and transcript levels in old bones. The researchers identified Tgfb2 as the most reduced Tgfb transcript in old bone, predominantly expressed by osteocytes. Proteomic analysis of the loading response showed modest changes compared to age-related differences, with fewer protein-level changes in old bones. The findings suggest that proteomics is a valuable tool for studying bone biology and can provide insights into protein-specific changes in aging.
The data obtained from the analysis were subjected to various statistical and data exploration techniques. Differential expression analysis was performed to compare protein abundance between different groups. Total RNA was extracted from the bones using TRIzol, and its integrity and concentration were measured. The bones were also processed for paraffin sectioning and RNA in situ hybridization.
Overall, the study involved the collection and analysis of bone samples from female mice to investigate age-related changes and loading responses in the skeletal system.
Click here to read the full research paper in Aging.
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Aging is indexed by PubMed/Medline (abbreviated as “Aging (Albany NY)”), PubMed Central, Web of Science: Science Citation Index Expanded (abbreviated as “Aging‐US” and listed in the Cell Biology and Geriatrics & Gerontology categories), Scopus (abbreviated as “Aging” and listed in the Cell Biology and Aging categories), Biological Abstracts, BIOSIS Previews, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science).
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“[…] our results suggest that sharing housing with others in early life might influence whole-life attributes, potentially leading to specific life history traits beyond the typical relationship between the growth rate and lifespan.”
A study on African turquoise killifish examined the impact of housing density on juvenile growth. Newly hatched fish were kept in different densities ranging from 1 to 40 fish per tank. It was found that lower housing densities resulted in faster growth, with fish in single housing growing significantly larger than those in group housing. Additionally, single-housed fish reached sexual maturity earlier compared to group-housed fish at higher densities. Comparisons between group-housed and single-housed fish showed that housing conditions in the juvenile stage did not affect the appearance changes during sexual maturation.
As the fish progressed to middle-aged adults, the rate of increase in body length slowed down, while body weight continued to increase. Differences in body weight between group-housed and single-housed fish persisted into old age, suggesting potential differences in body composition. Surprisingly, single-housed fish had a longer mean adult lifespan compared to group-housed fish, contradicting the commonly held belief that faster growth leads to shorter lifespan. Lower housing densities during the juvenile stage were also found to extend adult lifespan, further challenging the inverse correlation between growth rate and lifespan. These findings suggest that lower housing densities promote accelerated growth in the juvenile stage of African turquoise killifish.
The study also found that single-housed fish had a longer adult lifespan compared to group-housed fish. This led to the suspicion that the egg-laying period of single-housed fish might also be longer. To investigate this, the researchers conducted weekly monitoring of the number of eggs laid until the old adult stage. In group-housed fish, the number of eggs laid was high for the first two weeks, followed by a medium level for the subsequent five weeks, and then decreased. In contrast, single-housed fish showed a medium level of egg-laying for the first nine weeks, followed by a decrease. The cumulative number of live embryos was found to be lower in single-housed fish compared to group-housed fish. These findings suggest that while the number of eggs laid is not very high, single-housed fish have a longer egg-laying period than group-housed fish.
To investigate the potential reasons behind the reduction in offspring number and longer egg-laying period in single-housed fish, the researchers conducted RNA sequencing analysis of testes or ovaries at four life stages. These stages included the onset of sexual maturity, young adult, mature adult, and middle-aged adult. Interestingly, the analysis revealed that single-housed fish showed higher similarity to group-housed fish at earlier life stages compared to group-housed fish at the same life stage. For instance, in the testes, single-housed fish at stage II exhibited the highest similarity to group-housed fish at stage I. Similarly, in the ovaries, single-housed fish at stage II and III showed higher similarity to group-housed fish at stage I. These findings suggest that the rate of gonadal transcriptional change with life stage progression is slower in single-housed fish compared to group-housed fish.
The researchers identified differentially expressed genes (DEGs) between stage I and stage IV in group- and single-housed fish. In the testes, ribosome-related genes and cilium-related genes were highly enriched in DEGs with higher expression in stage I compared to stage IV, suggesting a link between life stage progression, testes development, and spermatogenesis. In the ovaries, growth-related genes and translation-related genes were highly enriched in DEGs with higher expression in stage I compared to stage IV, indicating a link between life stage progression, ovarian development, oogenesis, and aging. Comparing group-housed and single-housed fish at different stages, there were differences in the PC1 values, suggesting that single-housed fish exhibited slower progression of gametogenesis and gonadal maturation relative to life stage progression compared to group-housed fish.
To further investigate this, the researchers focused on specific genes related to spermatogenic differentiation, oocyte development, oocyte construction, and female gonad development. The expression of these genes showed slower changes with life stage progression in single-housed fish compared to group-housed fish in both the testes and ovaries. This suggests that single-housed fish may have slower rates of gametogenesis and gonadal maturation, leading to a lower proportion of mature sperm and oocytes in their gonads. Overall, the results indicate that, at the transcriptional level, the progression of gonadal maturation and ovarian aging is slower in single-housed fish compared to group-housed fish. This slower progression may explain the medium fecundity and extended egg-laying period observed in single-housed fish.
The liver was chosen for analysis as it plays a central role in organismal metabolic processes. Gene expression profiles of the livers were compared between group- and single-housed fish at two different ages: 7 weeks post-hatching (wph) and 14 wph. Surprisingly, despite the 2-week age difference, the correlation coefficients showed that group- and single-housed fish at 14 wph were highly similar. The researchers identified 1588 age-related differentially expressed genes (DEGs) between the two age groups. Hierarchical clustering based on the expression changes of these age-related genes demonstrated that the expression profiles of group- and single-housed fish were similar at 14 wph.
IN CONCLUSION
In summary, juvenile single housing in African turquoise killifish promotes faster growth, longer egg-laying periods, and extended lifespans compared to group housing. These findings challenge traditional assumptions about the relationship between growth and lifespan and shed light on the impact of early-life environmental conditions on overall life history.
Overall, the experiments involved maintaining and rearing the fish, measuring their body length and weight, analyzing RNA sequencing data, measuring lifespan, and counting the number of eggs laid. Statistical analysis was conducted to assess significant differences between groups.
Click here to read the full research paper in Aging.
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Aging is indexed by PubMed/Medline (abbreviated as “Aging (Albany NY)”), PubMed Central, Web of Science: Science Citation Index Expanded (abbreviated as “Aging‐US” and listed in the Cell Biology and Geriatrics & Gerontology categories), Scopus (abbreviated as “Aging” and listed in the Cell Biology and Aging categories), Biological Abstracts, BIOSIS Previews, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science).
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Researchers introduce SINGULAR, a cell rejuvenation atlas that provides a unified analysis framework to study the effects of rejuvenation strategies at the single-cell level.
Various strategies, including lifestyle changes, gene therapies, and surgical procedures, have shown promise in improving aging markers and increasing lifespan in model organisms. These interventions often have limitations, however, such as not achieving comprehensive functional improvement across tissues or facing challenges in clinical translation. To address these limitations, the researchers characterized and compared rejuvenation interventions at different biological levels. The paper introduces SINGULAR, a cell rejuvenation atlas that provides a unified analysis framework to study the effects of rejuvenation strategies at the single-cell level. By examining gene regulatory networks, intracellular signaling, cell-cell communication, and cellular processes, the atlas identifies master regulators and common targets across immune cells. SINGULAR has the potential to inform future advancements in human age reversal and aid in the selection of drugs that mimic the effects of rejuvenation interventions.
RESULTS
The authors propose a unified multiscale analysis pipeline for characterizing and comparing the effects of rejuvenation interventions. This process begins by filtering low-quality cells, normalizing expression profiles, and identifying optimal cell clustering. The data is then analyzed at various biological levels, including differential gene expression, transcriptional regulatory networks, signaling cascades, and intercellular communication.
Nine previously published single-cell RNA-seq datasets from different rejuvenation interventions were collected and analyzed, revealing technical variability that highlights the need for a standardized data processing pipeline. The analysis showed heterogeneous gene expression responses across different cell types and organs. Systemic interventions had consistent effects on multiple organs, while metformin had minimal impact. Interestingly, exercise produced the largest transcriptional effects in the liver, artery, and spinal cord, even though it primarily targets muscles.
Transcriptional regulatory networks (TRNs) were reconstructed to explore the regulatory mechanisms behind these gene expression changes. The TRNs, which averaged 72 genes, were highly hierarchical, indicating the presence of ‘master regulators’ that explain significant portions of gene expression changes.
To demonstrate the practical application of SINGULAR, the study investigated the identification of drugs that could target transcription factor (TF) master regulators and key signaling molecules. Drug-target relationships from DrugBank were analyzed to find drugs that could activate master regulators or mimic the effects of rejuvenation interventions. Interestingly, only 17 out of 239 TFs could be activated by drugs, primarily nuclear receptors, with notable exceptions like AP-1 complex proteins and Trp53. Some of these drugs, such as Curcumin and Vitamin D3, have shown rejuvenating effects on lifespan in model organisms. Key signaling molecules were found to be more druggable, with several drugs targeting specific molecules, though none targeted both genes.
The study aimed to identify master regulators and their downstream effects in rejuvenation interventions. By simulating the activation of transcription factors (TFs) within the network, the researchers quantified the number of genes regulated by each TF. They discovered 493 TFs with non-zero activity across various conditions, though most acted as master regulators in only a few cases. The study also highlighted key differences between TFs involved in aging-related activity changes and those regulating rejuvenation. Notably, the AP-1 complex, consisting of Fos and Jun, emerged as a common master regulator across multiple interventions. The researchers also identified TFs linked to aging and validated their potential rejuvenating effects experimentally. They also explored crosstalk between TFs and signaling pathways, finding negative enrichment of aging gene sets in several integrated networks. Overall, the findings offer valuable insights into the regulatory mechanisms and potential rejuvenating effects of master regulators and signaling molecules involved in rejuvenation interventions.
CONCLUSION
In conclusion, this study employed a unified analysis pipeline, SINGULAR, to compare the effects and mediators of various rejuvenation interventions. Key master regulators, including Arntl, AP-1 complex proteins, NFE2L2, and MAF, were identified as playing crucial roles in rejuvenation. The analysis revealed distinct differences between aging-related transcriptional changes and rejuvenation regulators. Immune and skin cell types were highlighted as potential intervention targets, with the possibility of additive or synergistic effects by targeting non-overlapping master regulators. Some limitations were noted, such as biases in cell type comparisons, reliance on ligand-receptor interactions for cell-cell communication analysis, and the risk of false negatives in differential expression testing. Despite these limitations, SINGULAR offers valuable insights into rejuvenation mechanisms and the identification of agents for anti-aging strategies. It provides a robust framework for understanding the mechanisms behind various interventions and offers a wide range of potential target genes for a comprehensive anti-aging approach.
Click here to read the full research paper in Aging.
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Aging is indexed by PubMed/Medline (abbreviated as “Aging (Albany NY)”), PubMed Central, Web of Science: Science Citation Index Expanded (abbreviated as “Aging‐US” and listed in the Cell Biology and Geriatrics & Gerontology categories), Scopus (abbreviated as “Aging” and listed in the Cell Biology and Aging categories), Biological Abstracts, BIOSIS Previews, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science).
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In this study, researchers reinforce knowledge about an age-related alteration in the synthesis of major proteins linked to the migratory and contractile functions of dermal human fibroblasts.
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Dermal fibroblasts orchestrate the synthesis and degradation of extracellular matrix components, which is crucial for skin homeostasis. Alterations in the expression of components such as collagens and enzymes can lead to reduced mechanical cutaneous tension and impaired skin wound healing during aging.
Researchers Françoise Boismal, Sandy Peltier, Sophie Ly ka so, Guillaume Chevreux, Loïse Blondel, Kévin Serror, Niclas Setterblab, Elina Zuelgaray, David Boccara, Maurice Mimoun, Christelle Guere, Armand Benssussan, Marie Dorr, Gallic Beauchef, Katell Vie, and Laurence Michel from Saint-Louis Hospital, Paris; Paris University, Paris Cité; Jacques-Monod Institute, Paris; and Clarins Laboratories, Pontoise, aimed to better understand the molecular alterations in fibroblasts during aging by comparing secretomic and proteomic signatures of fibroblasts from young (<35years) and aged (>55years) skin donors, in quiescence or TGF-stimulated conditions, using HLPC/MS.
Dermal fibroblasts were obtained from healthy, sun-protected skin of young (<35 years) and aged (>55 years) healthy women undergoing breast reduction surgery. Peptides were loaded using an online preconcentration method and separated by chromatography. RNA extraction, reverse transcription, quantitative PCR, and blot quantification were performed, along with immunostaining on fibroblasts seeded on culture chamber slides.
To identify key molecules involved in the role of human dermal fibroblasts during wound healing and skin aging, a comparative analysis of the secretome and proteome of 12 fibroblast cultures, freshly isolated from young and mature skin, was conducted using HPLC/MS. This analysis was performed in both quiescence and TGF-β1-treated conditions, without senescence-inducing factors, as described in previously reported aging models. Importantly, the analyses were conducted in the absence of serum in the culture medium 24 hours before and during cell stimulation to avoid serum protein contamination in the secretomic and proteomic assays
This study revealed a significant decrease in fibroblast protein secretion with age, while cytoplasmic protein accumulation increased by over 60%. Proteins related to actin and ECM (extracellular matrix) organization were the two main categories altered during aging. An in-depth analysis of actin-related proteins highlighted the involvement of CFL1, CORO1C, the ARP2/3 complex, FLNB, and ACTC1 in cytoskeleton organization and fibroblast migration. These findings offer potential new targets to slow key features of skin aging.
“Our present data reinforce knowledge about an age-related alteration in the synthesis of major proteins linked to the migratory and contractile functions of dermal human fibroblasts.” Read the full research paper, published in Aging.
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In this study, researchers use neuroimaging to see how menopause alters brain structure and connectivity in postmenopausal women.
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Menopause marks the beginning of the next biological chapter in a woman’s life. Characterized by the natural ebb of reproductive hormones (particularly estrogen), menopause ushers in a new season of aging. This hormonal shift not only signifies a transition in fertility but also influences systemic health. The menopause-associated decline in estrogen has been associated with various health issues, including alterations in brain structure and function. However, the mechanics of this phenomenon are still poorly understood. A greater understanding of how menopause alters the brain could aid in the early detection, and possible prevention, of neurodegenerative disease.
“To the best of our knowledge, no comparative neuroimaging study on alterations in the brain volume and functional connectivity, especially focusing on the thalamic subnuclei in premenopausal vs. postmenopausal women has been reported.”
The Study
The decline in estrogen levels during menopause has been linked to an elevated risk of neurodegenerative diseases, notably Alzheimer’s disease (AD). Estrogen plays a pivotal role in modulating neurotransmitter systems, neurotrophins, and brain cytoarchitecture, and there is evidence that these interactions also affect mood, memory, and cognition. The biological mechanisms underlying the increased AD risk in postmenopausal women are not fully understood.
In this study, 21 premenopausal women and 21 postmenopausal women were subjected to magnetic resonance imaging (MRI). The researchers utilized T1-weighted MRI and resting-state functional MRI data to assess differences in brain volume and seed-based functional connectivity. For statistical analysis, they employed multivariate analysis of variance, factoring in age and whole brain volume as covariates, to compare the surface areas and subcortical volumes between the two groups.
Results
Postmenopausal women showed significantly smaller cortical surface, especially in the left medial orbitofrontal cortex (mOFC), right superior temporal cortex (STC), and right lateral orbitofrontal cortex, compared to premenopausal women. These findings suggest that diminished brain volume may be linked to menopause-related symptoms caused by lower sex hormone levels.
In addition to structural changes, the functional connectivity between the brain regions also showed changes. The study found significantly decreased functional connectivity between the left mOFC and the right thalamus in postmenopausal women — reinforcing the hypothesis that the left orbitofrontal-bilateral thalamus connectivity is associated with cognitive impairment. Although postmenopausal women did not show volume atrophy in the right thalamus, the volume of the right pulvinar anterior (PuA), a significant thalamic subnuclei, was significantly decreased. Decreased PuA volume in postmenopausal women is closely related to decreases in female sex hormone levels following menopause.
Expectedly, the study found a significant difference in age and sex hormone levels between premenopausal and postmenopausal women. Postmenopausal women had lower total estrogen and estradiol (E2) levels and higher follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels than premenopausal women. Estrogen levels were positively correlated with the surface area of the left mOFC, right STC, and right lOFC, as well as the volume of the right PuA.
“Concerning the close connection between the estrogen level and STC volume, our findings support a potential role of decreases in sex hormones following menopause due to the correspondent brain structural atrophy. However, further study is needed to elucidate the specific cognitive and emotional implications in connection with these structural changes.”
Conclusions & Future Directions
Postmenopausal women showed significantly lower left mOFC, right lOFC, and right STC surface areas, reduced right PuA volume, and decreased left mOFC-right thalamus functional connectivity compared to premenopausal women. These findings provide novel insight into the structural and functional changes in the brain associated with menopause. However, further research is needed to validate these findings in a larger cohort and to understand the potential cognitive implications of these changes.
“Our findings provide novel insight into the structural and functional changes in the brain associated with menopause.”
Click here to read the full research paper published in Aging.
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Aging is an open-access, traditional, peer-reviewed journal that publishes high-impact papers in all fields of aging research. All 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.
In Aging’s Volume 14, Issue 15, cover paper, researchers hypothesized that multidimensional well-being may prolong mobility-limitation-free survival and longevity among older adults.
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The word “well-being” is commonly used in workplace environments, therapy sessions, doctor’s offices, books, online, and elsewhere. However, the definition of this word seems to differ across varying contexts, cultures, traditions, values, and even biological sexes. Below are four definitions of well-being:
“noun: [Well-being is] the state of being comfortable, healthy, or happy.” — Oxford English Dictionary
“The meaning of WELL-BEING is the state of being happy, healthy, or prosperous : welfare.” — Merriam-Webster Dictionary
“Well-being, or wellbeing, also known as wellness, prudential value or quality of life, refers to what is intrinsically valuable relative to someone. So the well-being of a person is what is ultimately good for this person, what is in the self-interest of this person.” — Wikipedia
Based on these definitions, one could argue the root meaning of well-being may be distilled down to individual happiness and prosperity that contributes to healthy aging. However, this prosperity and happiness is not anchored to only one domain of well-being. There are three domains of being well, which include behavioral, social and psychological well-being.
Aging & Well-Being
“Successful aging is a multidimensional construct covering behavioral, social, and psychological domains of well-being, all amenable to individual actions and public health interventions [1–4].”
“Despite the rising evidence supporting a multidimensional construct of successful aging, most longitudinal studies still fail to cover well-being indicators belonging to different domains, as shown by the disproportionate amount of literature focusing exclusively on lifestyle factors [45–48].”
Three Domains of Well-Being: 10 Indicators
In their current study, the researchers selected 10 indicators of behavioral, social and psychological well-being: 1) Behavioral: Mediterranean diet, smoking, physical leisure activities, and mental leisure activities; 2) Social: Social leisure activities (i.e., social participation), social connections and socialsupport; 3) Psychological: life satisfaction, negative affect and positive affect.
“Blue zones” are areas around the world with high concentrations of centenarians, or people who live to be over 100 years old. A prevalent diet among people living in blue zones is the Mediterranean diet. The Mediterranean diet consists of fruits, vegetables, whole grains, beans, nuts/seeds, lean poultry, fish, seafood, dairy, eggs, and extra virgin olive oil. This diet has been closely studied as a protective factor of healthy aging.
The psychological well-being indicator listed as “negative affect” refers to the degree to which a person feels guilt, anger and fear, and the following features are considered: distressed, upset, scared, nervous, and afraid. “Positive affect” considers the extent to which a person is active, inspired, determined, alert, and enthusiastic. For additional explanations, the remaining indicators of well-being used in this study are expounded in thorough detail within the research paper itself.
Aging & Mobility
“Mobility decline precedes disability and premature death, and is therefore considered an optimal early indicator of physical function decay among older adults [34].”
The simple ability to exercise, complete day-to-day chores and maintain personal hygiene all rely on a minimum range of physical mobility. A sedentary lifestyle is a well-recognized risk factor for chronic diseases, such as obesity, type 2 diabetes, cardiovascular disease, and some forms of cancer. Furthermore, mobility limitations are associated with social isolation, depression and cognitive decline. The researchers in this study aimed to identify well-being profiles and their association with mobility-limitation-free survival.
“The specific aims of this study were: 1) to identify distinct well-being profiles among men and women separately, by using latent class analysis; 2) to determine which of these profiles are associated with the greatest benefit in terms of mobility-limitation-free survival; and 3) to quantify these potential benefits in absolute terms by calculating differences in median age at onset of mobility limitation or death across profiles.”
The Study
The study population consisted of 1488 functionally healthy individuals (after all exclusion criteria were applied to the ongoing Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) population-based study). In addition to collecting self-reported data on the 10 indicators of behavioral, social and psychological well-being listed above, the researchers included data on the participants’ covariates. Covariates included age, education, number of chronic diseases, mini-Mental State Examination score (MMSE), and NEO Five-Factor Inventory (NEO-FFI) questionnaire. At the beginning of the study (baseline), the average age in the cohort was 69 years old (with a standard deviation of +/- 8.3 years). Ninety-one percent of participants had at least a high-school-level of education. Females (59%) composed the majority of the cohort.
“In this study, we used latent class analysis to detect data-driven subgroups of people with similar well-being profiles according to behavioral (diet, smoking, and physical and mental leisure activities), social (social participation, connections, and support) and psychological (life satisfaction, positive and negative affect) well-being indicators, as defined by the Centers for Disease Control and Prevention (CDC) [25].”
Since men and women tend to behave differently when it comes to multiple factors of well-being, the researchers stratified their analyses by sex. They scheduled regular followed-ups with these participants over the course of 15 years. Well-being profiles were derived from the 10 well-being indicators using latent class analysis. Endpoints were defined as mobility-limitation-free survival, limited mobility or death. Limited mobility was defined as having a walking speed below 0.8 meters per second.
“A composite endpoint, considered to be an indicator of mobility-limitation-free survival, was operationalized by taking into account the time from study entry until the development of mobility limitation (i.e., walking speed <0.8m/s) or death, whichever occurred first.”
Results
At baseline, the researchers identified three well-being profiles among both men and women that followed a clear gradient in all behavioral, social and psychological indicators throughout the study. Participants categorized in the best well-being profile had high adherence to the Mediterranean diet, the lowest proportion of current smokers, high engagement with leisure activities, and the highest levels of social and psychological well-being. Those in the intermediate well-being profile had low/moderate adherence to the Mediterranean diet, a higher proportion of former/never smokers, and moderate levels of social and psychological well-being. (Men in the intermediate well-being profile had a low/moderate engagement in leisure activities, while women had moderate/high engagement levels.) Participants in the worst well-being profile had low adherence to the Mediterranean diet, a higher proportion of former/never smokers, the lowest levels of leisure activity engagement, and the lowest levels of social and psychological well-being.
To examine the association between these well-being profiles and the incidence of mobility limitation or death, the researchers used Cox and Laplace regression models and applied sensitivity analyses to the data.
“In agreement with the Cox regressions, results from Laplace regressions showed that men in the intermediate and best profiles survived 1 and 3 years longer without mobility limitations, respectively, compared to those in the worst profile after adjustment for potential confounders (Figure 2). Women in the intermediate and best profiles lived 2 and 3 years longer without mobility limitations, respectively, compared to those in the worst profile.”
Conclusion
The well-being profiles of older adults are associated with their risk of developing mobility limitations and death. Those in the best well-being profile had the lowest risk, while those in the worst well-being profile had the highest risk. These findings suggest that interventions to improve multi-domain well-being in older adults may improve longevity and help reduce the incidence of mobility limitations in old age. Although this study has many strengths, the researchers were forthcoming about its limitations. Future studies are recommended to confirm these findings.
“While theoretical insights into different models of successful aging are on the rise, empirical evidence from population-based longitudinal data on the complex interplay among the distinct well-being domains and their association with person-centered outcomes, such as mobility-limitation-free survival, is currently lacking. This study addresses such an important gap and provides further evidence to better understand and promote functional independence in community-dwelling older adults through primary prevention multi-domain interventions.”
Click here to read the full research paper published by Aging.
Agingis an open-access journal that publishes research papers bi-monthly in all fields of aging research. These papers are available at no cost to readers on Aging-us.com. Open-access journals have the power to benefit humanity from the inside out by rapidly disseminating information that may be freely shared with researchers, colleagues, family, and friends around the world.
