Biological Aging Process Research Articles

Relationship between DNA damage measured by the comet-assay and cognitive function

Recent studies exploring the relationship between DNA damage measured by the comet assay (single-cell gel electrophoresis) and cognitive function in both animal models and humans are reviewed and summarized. This manuscript provides an overview of studies exploring cognitive dysfunction related to DNA damage due to biological ageing process, cancer treatment, adverse environmental or occupational exposures, and prenatal genotoxic exposure. The review confirms the potential of comet assay to further explore the link between DNA damage, as indicative of genomic instability, and cognitive impairment in different research and clinical areas. Analysed studies support, in fact, the significant relationship between DNA damage and cognitive impairment, mainly affecting attention, working memory and executive functions. These cognitive domains are crucial to daily functioning and occupational performance, with important clinical implications. Although evidence support the relationship between DNA damage measured by the comet assay and cognitive function in different settings, further longitudinal research is needed to disentangle the temporal relationship between them over time, and to explore the potential of comet assay-detected DNA lesions to predict response to interventions.

Clinical Applications of Photofunctionalization on Dental Implant Surfaces: A Narrative Review.

Dental implant therapy is a common clinical procedure for the restoration of missing teeth. Many methods have been used to promote osseointegration for successful implant therapy, including photofunctionalization (PhF), which is defined as the modification of titanium surfaces after ultraviolet treatment. It includes the alteration of the physicochemical properties and the enhancement of biological capabilities, which can alter the surface wettability and eliminate hydrocarbons from the implant surface by a biological aging process. PhF can also enhance cellular migration, attachment, and proliferation, thereby promoting osseointegration and coronal soft tissue seal. However, PhF did not overcome the dental implant challenge of oral cancer cases. It is necessary to have more clinical trials focused on complex implant cases and non-dental fields in the future.

Immune checkpoint inhibitor (ICI) genes and aging in malignant melanoma patients: a clinicogenomic TCGA study

BackgroundCancer diagnoses and deaths among the elderly (65 +) are expected to increase significantly over the next decade. Immune checkpoint inhibitors specifically target ICI genes and enhance immune system function. However, poor outcomes may be associated with aging.MethodsWe downloaded the Genomic Data Commons from the Cancer Genome Atlas (TCGA) and collected gene expression data from malignant melanoma (MM) tissues, the third level as the primary site. The CKTTD ICI genes database were applied and validated using the GEO database and lab experiments.ResultsIn 414 patients, 13 ICI genes were obtained as risk gene signature by univariate and multivariate Cox hazard models and were associated with poor survival in the older group. At 1, 3, and 5 years (79%, 76%, and 76%, respectively), we investigate TNFRFS4 gene and age prediction using novel nomogram-associated aging (HR = 1.79, P 0.001, CI = 1.32–2.45) with higher sensitivity testing.TNFRSF4 gene expression was significantly high in younger (15 years interval) MM patients (P < 0.001). By correlation analysis, a significant negative association was determined (P < 0.001). The validation of gene correlation from GEO (GSE59455) and (GSE22153) was obtained as external validation. We tested the TNFRSF4 protein levels by IHC in 14 melanoma tissue samples. TNFRSF4 expression was observed to be lower expressed in the older of melanoma tissues, and higher in the younger age group (P = 0.02). Besides the connectivity of ICI gene proteins, the biological processes of cell aging, aging, and the immune system were found to be highly related.ConclusionsAlong with the risk score evaluation, the ICI gene (TNFRSF4) was identified as a tumor suppressor gene related to inequalities in age survival and associated with immune cell infiltrations. The aging responses of melanoma patients and related gene expression need further investigation in order to identify potential therapeutic targets.

NMR Spectroscopy Combined with Machine Learning Approaches for Age Prediction in Healthy and Parkinson’s Disease Cohorts through Metabolomic Fingerprints

Biological aging can be affected by several factors such as drug treatments and pathological conditions. Metabolomics can help in the estimation of biological age by analyzing the differences between predicted and actual chronological age in different subjects. In this paper, we compared three different and well-known machine learning approaches—SVM, ElasticNet, and PLS—to build a model based on the 1H-NMR metabolomic data of serum samples, able to predict chronological age in control individuals. Then, we tested these models in two pathological cohorts of de novo and advanced PD patients. The discrepancies observed between predicted and actual age in patients are interpreted as a sign of a (pathological) biological aging process.

Epigenetic aging, knee pain and physical performance in community-dwelling middle-to-older age adults.

Knee pain is a leading cause of disability in the aging population and may indirectly accelerate biological aging processes. Chronological aging increases the risk of developing of knee pain and knee pain reduces physical function; however, limited data exist on how epigenetic aging, a known hallmark of biological aging shown to predict health span and mortality, may influence this relationship. The purpose of this study was to examine whether decreased physical performance associated with knee pain is mediated by markers of epigenetic aging. Participants (57.91±8.04years) with low impact knee pain (n=95), high impact knee pain (n=53) and pain-free controls (n=26) completed self-reported pain, a blood draw and a short physical performance battery (SPPB) that included balance, walking, and sit to stand tasks. We employed an epigenetic clock previously associated with knee pain and shown to predict overall mortality risk (DNAmGrimAge). Bootstrapped-mediation analyses were used to determine associations of DNAmGrimAge and SPPB between pain groups. Those with high impact and low impact pain had a biologically older epigenetic age (5.14y±5.66 and 1.32y±5.41, respectively). However, while there were direct effects of pain on overall physical performance, these were not explained by epigenetic aging. Epigenetic aging only mediated the effect of pain on balance performance. Future work is needed to examine pain's impact on biological aging processes including epigenetic aging and its ultimate effect on physical function measures known to predict health span and mortality.

Cardiovascular prevention in old age-Cardiovascular prevention of ageing?

Cardiovascular prevention is also particularly successful in old people in terms of preventing major cardiovascular events. The concept of prevention of geriatric diseases can, however, be expanded taking the insights of geroscience into consideration, so that slowing the ageing process per se can be set as anew goal: ageing is the pertinent basis of nearly all chronic diseases in adulthood, aline of argument for which the cardiovascular system can serve as aprototype. Consequently, treating ageing can help prevent the typical chronic diseases in old people, i.e. multimorbidity and frailty. According to the current guidelines of the European Society of Cardiology (ESC, Eur Heart J 42:3227-3337, 2021) and the German Society for Cardiology (DGK, https://leitlinien.dgk.org/files/03_pocket_leitlinien_praevention_aktualisiert.pdf ) cardiovascular prevention incorporates age-stratified and individually adapted measures and treatment targets in the domains lifestyle (physical activity, body weight, nutrition), psychosocial factors, cardiovascular risk factors (smoking, blood lipids, blood pressure, diabetes), antithrombotic treatment and disease-specific interventions. From abiogerontological perspective, in the midterm these measures could be supplemented by measures and medicinal treatment strategies to slow the biological ageing process, e.g. with senolytics and metformin. Initial clinical studies using senolytics have already been reported.

The future of treating aging

The number of adults aged 65 and older in the United States and globally is expected to nearly double in size by 2050. It will be necessary to devise strategies spanning the science, healthcare, and regulatory sectors to support the growing number of older adults and adapt to the changes of population aging. Given the greater disease risk in older individuals, this population shift also presents new opportunities for research and development of both preventive and therapeutic interventions that target a wide range of chronic conditions. Many previous articles have focused on the advantages and drawbacks of classifying aging as a disease, which we briefly summarize. Then, we focus on the discussion of actionable steps to adapt the healthcare system and clinical regulatory frameworks to support research in geroscience, develop novel therapeutics that delay the biological aging process, and promote the translation of these therapies to patients.

Physicochemical and biological ageing processes of (micro)plastics in the environment: a multi-tiered study on polyethylene

Pollution by plastic and microplastic impacts the environment globally. Knowledge on the ageing mechanisms of plastics in natural settings is needed to understand their environmental fate and their reactivity in the ecosystems. Accordingly, the study of ageing processes is gaining focus in the context of the environmental sciences. However, laboratory-based experimental research has typically assessed individual ageing processes, limiting environmental applicability. In this study, we propose a multi-tiered approach to study the environmental ageing of polyethylene plastic fragments focusing on the combined assessment of physical and biological processes in sequence. The ageing protocol included ultraviolet irradiation in air and in a range of water solutions, followed by a biofouling test. Changes in surface characteristics were assessed by Fourier transform infrared spectroscopy, scanning electron microscopy, and water contact angle. UV radiation both in air and water caused a significant increase in the density of oxidized groups (i.e., hydroxyl and carbonyl) on the plastic surface, whereby water solution chemistry influenced the process both by modulating surface oxidation and morphology. Biofouling, too, was a strong determinant of surface alterations, regardless of the prior irradiation treatments. All biofouled samples present (i) specific infrared bands of new surface functional groups (e.g., amides and polysaccharides), (ii) a further increase in hydroxyl and carbonyl groups, (iii) the diffuse presence of algal biofilm on the plastic surface, and (iv) a significant decrease in surface hydrophobicity. This suggests that biological-driven alterations are not affected by the level of physicochemical ageing and may represent, in real settings, the main driver of alteration of both weathered and pristine plastics. This work highlights the potentially pivotal role of biofouling as the main process of plastic ageing, providing useful technical insights for future experimental works. These results also confirm that a multi-tiered laboratory approach permits a realistic simulation of plastic environmental ageing in controlled conditions.

Tea Polyphenols as Prospective Natural Attenuators of Brain Aging.

No organism can avoid the process of aging, which is often accompanied by chronic disease. The process of biological aging is driven by a series of interrelated mechanisms through different signal pathways, including oxidative stress, inflammatory states, autophagy and others. In addition, the intestinal microbiota play a key role in regulating oxidative stress of microglia, maintaining homeostasis of microglia and alleviating age-related diseases. Tea polyphenols can effectively regulate the composition of the intestinal microbiota. In recent years, the potential anti-aging benefits of tea polyphenols have attracted increasing attention because they can inhibit neuroinflammation and prevent degenerative effects in the brain. The interaction between human neurological function and the gut microbiota suggests that intervention with tea polyphenols is a possible way to alleviate brain-aging. Studies have been undertaken into the possible mechanisms underpinning the preventative effect of tea polyphenols on brain-aging mediated by the intestinal microbiota. Tea polyphenols may be regarded as potential neuroprotective substances which can act with high efficiency and low toxicity.

Physical Activity, Inflammation, and Physical Function in Older Adults: Results From the Health & Retirement Study.

A cross-sectional secondary data analysis from Wave 13 of the Health & Retirement Study (HRS) core biennial data and Venous Blood Study (VBS) was conducted. Structural equation modeling was used to establish the model and test the relationships. Chronic low-level inflammation was moderately negatively correlated with physical activity (r = -0.326) and function (r = -0.367). Latent regressions showed that higher physical activity is associated with better physical function (unstandardized estimate = 0.600, p < .001) while inflammation negatively affects physical function (unstandardized estimate = -0.139, p < .001), and adiposity was not a predictor in the model (p = 0.055). For older adults, preserving physical function by participation in physical activity and decreasing chronic inflammation are key preventive health strategies for older adults to maintain independence, with a need to further explore pro and anti-inflammatory biomarkers.

A Review of the Potential Effects of Melatonin in Compromised Mitochondrial Redox Activities in Elderly Patients With COVID-19.

Melatonin, an endogenous indoleamine, is an antioxidant and anti-inflammatory molecule widely distributed in the body. It efficiently regulates pro-inflammatory and anti-inflammatory cytokines under various pathophysiological conditions. The melatonin rhythm, which is strongly associated with oxidative lesions and mitochondrial dysfunction, is also observed during the biological process of aging. Melatonin levels decline considerably with age and are related to numerous age-related illnesses. The signs of aging, including immune aging, increased basal inflammation, mitochondrial dysfunction, significant telomeric abrasion, and disrupted autophagy, contribute to the increased severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. These characteristics can worsen the pathophysiological response of the elderly to SARS-CoV-2 and pose an additional risk of accelerating biological aging even after recovery. This review explains that the death rate of coronavirus disease (COVID-19) increases with chronic diseases and age, and the decline in melatonin levels, which is closely related to the mitochondrial dysfunction in the patient, affects the virus-related death rate. Further, melatonin can enhance mitochondrial function and limit virus-related diseases. Hence, melatonin supplementation in older people may be beneficial for the treatment of COVID-19.

Associations between exposure to adverse childhood experiences and biological aging: Evidence from the Canadian Longitudinal Study on Aging

People exposed to adverse childhood experiences (ACEs) suffer from an increased risk of chronic disease and shorter lifespan. These individuals also tend to exhibit accelerated reproductive development and show signs of advanced cellular aging as early as childhood. These observations suggest that ACEs may accelerate biological processes of aging through direct or indirect mechanisms; however, few population-based studies have data to test this hypothesis. We analysed ACEs and biological aging data from the Canadian Longitudinal Study on Aging (CLSA; n = 23,354 adults aged 45–85) and used the BioAge R package to compute three indices of biological aging from blood-chemistry and organ-function data: Klemera-Doubal method (KDM) biological age, phenotypic age (PA), and homeostatic dysregulation (HD). Adults with ACEs tended to be biologically older than those with no ACEs, although the observed effect-sizes were small (Cohen’s d<0.15), with the exception of neglect (d=0.35 for KDM and PA). Associations were similar for men and women and tended to be smaller for older as compared to midlife participants. Subtypes of ACEs perceived as being more severe (e.g., being pushed or kicked, experiencing forced sexual activity, witnessing physical violence) and more frequent and diverse exposures were associated with relatively larger effect-sizes. These findings support the hypothesis that ACEs contribute to accelerated biological aging, although replication is needed in studies with access to prospective records of ACEs and cellular-level measurements of biological aging. Furthermore, future work to better understand the degree to which associations between ACEs and biological aging are moderated by specific life-course pathways, and mediated by lifestyle and socioeconomic factors is warranted.

Epigenetic age acceleration in U.S. testicular cancer survivors (TCS).

5033 Background: Given the young age at diagnosis and effective therapies (cisplatin-based chemotherapy and/or surgical approaches), most TCS gain many decades of life. Attention has been drawn to the potential downsides of these treatment successes, including the accelerated development of age-related diseases. Previous studies have suggested that cytotoxic treatment and carcinogenesis are associated with epigenetic changes, leading to premature biological aging processes. Methods: We recruited 24 TCS managed with surgical approaches alone and 24 cisplatin-treated TCS (all also treated with surgical removal of the cancerous testis) and who had histologic/serological germ cell tumor diagnosis before 55 years, and were disease-free at routine follow up. We also included 310 cancer-free race- and age-matched (+/- 5 years) males from a normative cohort, i.e., the Coronary Artery Risk Development in Young Adults (CARDIA) Study. We undertook genome-wide interrogation of blood DNA methylation (DNAm) using the Illumina Infinium Methylation EPIC BeadChip (EPIC array). We quantified aging using DNAm GrimAge, a validated, composite biomarker consisting of DNAm surrogate biomarkers of seven plasma proteins associated with various age-related conditions plus a DNAm surrogate of smoking pack-years. The comparison analysis was adjusted for age, race, smoking status, blood cell type proportions estimated using DNA methylation batch effect, and other laboratory-related technical factors. Results: The median chronological age of TCS was 28 years (range 19-64) with 25% smokers. Compared to their chronological age, TCS managed with surgical approaches alone had a mean GrimAge of 39.4 years (i.e., 9.2 years older, paired t-test P = 0.001), and cisplatin-treated TCS had a mean GrimAge of 45.2 years (i.e., 14.9 years older, paired t-test P &lt; 0.001). Compared to the matched CARDIA controls, TCS managed with surgical approaches alone were on average 3.0 years epigenetically older (P = 0.093), and cisplatin-treated TCS were on average 11.2 years epigenetically older (P &lt; 0.001), suggesting an increasing trend with treatment burden (P-trend &lt; 0.001). Conclusions: Our data showed a faster epigenetic aging process in TCS. Consistent with previous studies, our data is in line with the hypothesis that TC cytotoxic treatment may induce premature aging. Although TCS managed with surgical approaches alone had no exposure to cytotoxic drugs, their epigenetic age may also be accelerated due to TC development and/or risk factors that contributed to it as well as post-therapy factors.

Epigenetic age predictors in community-dwelling adults with high impact knee pain.

Gerontological research reveals considerable interindividual variability in aging phenotypes, and emerging evidence suggests that high impact chronic pain may be associated with various accelerated biological aging processes. In particular, epigenetic aging is a robust predictor of health-span and disability compared to chronological age alone. The current study aimed to determine whether several epigenetic aging biomarkers were associated with high impact chronic pain in middle to older age adults (44–78 years old). Participants (n = 213) underwent a blood draw, demographic, psychosocial, pain and functional assessments. We estimated five epigenetic clocks and calculated the difference between epigenetic age and chronological age, which has been previously reported to predict overall mortality risk, as well as included additional derived variables of epigenetic age previously associated with pain. There were significant differences across Pain Impact groups in three out of the five epigenetic clocks examined (DNAmAge, DNAmPhenoAge and DNAmGrimAge), indicating that pain-related disability during the past 6 months was associated with markers of epigenetic aging. Only DNAmPhenoAge and DNAmGrimAge were associated with higher knee pain intensity during the past 48 h. Finally, pain catastrophizing, depressive symptomatology and more neuropathic pain symptoms were significantly associated with an older epigenome in only one of the five epigenetic clocks (i.e. DNAmGrimAge) after correcting for multiple comparisons (corrected p’s < 0.05). Given the scant literature in relation to epigenetic aging and the complex experience of pain, additional research is needed to understand whether epigenetic aging may help identify people with chronic pain at greater risk of functional decline and poorer health outcomes.

Biological aging processes underlying cognitive decline and neurodegenerative disease.

Alzheimer’s disease and related dementias (ADRD) are among the top contributors to disability and mortality in later life. As with many chronic conditions, aging is the single most influential factor in the development of ADRD. Even among older adults who remain free of dementia throughout their lives, cognitive decline and neurodegenerative changes are appreciable with advancing age, suggesting shared pathophysiological mechanisms. In this Review, we provide an overview of changes in cognition, brain morphology, and neuropathological protein accumulation across the lifespan in humans, with complementary and mechanistic evidence from animal models. Next, we highlight selected aging processes that are differentially regulated in neurodegenerative disease, including aberrant autophagy, mitochondrial dysfunction, cellular senescence, epigenetic changes, cerebrovascular dysfunction, inflammation, and lipid dysregulation. We summarize research across clinical and translational studies to link biological aging processes to underlying ADRD pathogenesis. Targeting fundamental processes underlying biological aging may represent a yet relatively unexplored avenue to attenuate both age-related cognitive decline and ADRD. Collaboration across the fields of geroscience and neuroscience, coupled with the development of new translational animal models that more closely align with human disease processes, is necessary to advance novel therapeutic discovery in this realm.

Dietary Supplements and Natural Products: An Update on Their Clinical Effectiveness and Molecular Mechanisms of Action During Accelerated Biological Aging.

Accelerated biological aging, which involves the gradual decline of organ or tissue functions and the distortion of physiological processes, underlies several human diseases. Away from the earlier free radical concept, telomere attrition, cellular senescence, proteostasis loss, mitochondrial dysfunction, stem cell exhaustion, and epigenetic and genomic alterations have emerged as biological hallmarks of aging. Moreover, nutrient-sensing metabolic pathways are critical to an organism’s ability to sense and respond to nutrient levels. Pharmaceutical, genetic, and nutritional interventions reverting physiological declines by targeting nutrient-sensing metabolic pathways can promote healthy aging and increase lifespan. On this basis, biological aging hallmarks and nutrient-sensing dependent and independent pathways represent evolving drug targets for many age-linked diseases. Here, we discuss and update the scientific community on contemporary advances in how dietary supplements and natural products beneficially revert accelerated biological aging processes to retrograde human aging and age-dependent human diseases, both from the clinical and preclinical studies point-of-view. Overall, our review suggests that dietary/natural products increase healthspan—rather than lifespan—effectively minimizing the period of frailty at the end of life. However, real-world setting clinical trials and basic studies on dietary supplements and natural products are further required to decisively demonstrate whether dietary/natural products could promote human lifespan.

MiR-10a, miR-30c, and miR-451a Encapsulated in Small Extracellular Vesicles Are Prosenescence Factors in Human Dermal Fibroblasts

Although small extracellular vesicles (sEV) have been reported to play an important role in cellular senescence and aging, little is known about the potential role and function of microRNAs (miRNAs) contained within the sEV. To determine the senescence-associated factors secreted from sEV of human dermal fibroblasts (HDFs), we isolated and characterized sEV from nonsenescent versus that from senescent HDFs. Small RNA-sequencing analysis identified many enriched miRNAs in sEV of senescent HDF, as shown by the upregulation of miR-10a, miR-30c, and miR-451a and downregulation of miR-128, miR-184, miR-200c, and miR-125a. Overexpression of miR-10a, miR-30c, and miR-451a induced an aging phenotype in HDFs, whereas inhibition of these miRNAs reduced senescent-like phenotypes in senescent HDFs. Moreover, treatment with sEV or sEV-containing conditioned medium promoted cellular senescence in HDFs, whereas sEV depletion abrogated prosenescence effects of the senescent HDF secretome. Interestingly, prosenescence sEV miRNAs were found to have an essential role in regulating ROS production and mitophagy activation. Taken together, our results revealed miR-10a, miR-30c, and miR-451a as prosenescence factors that are differentially expressed in sEV of senescent HDFs, showing the essential role of sEV miRNAs in the biological processes of aging.

Aging of the Immune System: Focus on Natural Killer Cells Phenotype and Functions.

Aging is the greatest risk factor for nearly all major chronic diseases, including cardiovascular diseases, cancer, Alzheimer’s and other neurodegenerative diseases of aging. Age-related impairment of immune function (immunosenescence) is one important cause of age-related morbidity and mortality, which may extend beyond its role in infectious disease. One aspect of immunosenescence that has received less attention is age-related natural killer (NK) cell dysfunction, characterized by reduced cytokine secretion and decreased target cell cytotoxicity, accompanied by and despite an increase in NK cell numbers with age. Moreover, recent studies have revealed that NK cells are the central actors in the immunosurveillance of senescent cells, whose age-related accumulation is itself a probable contributor to the chronic sterile low-grade inflammation developed with aging (“inflammaging”). NK cell dysfunction is therefore implicated in the increasing burden of infection, malignancy, inflammatory disorders, and senescent cells with age. This review will focus on recent advances and open questions in understanding the interplay between systemic inflammation, senescence burden, and NK cell dysfunction in the context of aging. Understanding the factors driving and enforcing NK cell aging may potentially lead to therapies countering age-related diseases and underlying drivers of the biological aging process itself.

Ageing with HIV: Challenges and biomarkers.

SummaryThe antiretroviral treatment (ART) developed to control HIV infection led to a revolution in the prognosis of people living with HIV (PLWH). PLWH underwent from suffering severe disease and often fatal complications at young ages to having a chronic condition and a life expectancy close to the general population. Nevertheless, chronic age-related diseases increase as PLWH age. The harmful effect of HIV infection on the individual's immune system adds to its deterioration during ageing, exacerbating comorbidities. In addition, PLWH are more exposed to risk factors affecting ageing, such as coinfections or harmful lifestyles. The ART initiation reverses the biological ageing process but only partially, and additionally can have some toxicities that influence ageing. Observational studies suggest premature ageing in PLWH. Therefore, there is considerable interest in the early prediction of unhealthy ageing through validated biomarkers, easy to implement in HIV-clinical settings. The most promising biomarkers are second-generation epigenetic clocks and integrative algorithms.

Integrating DNA Methylation Measures of Biological Aging into Social Determinants of Health Research.

Acceleration of biological processes of aging is hypothesized to drive excess morbidity and mortality in socially disadvantaged populations. DNA methylation measures of biological aging provide tools for testing this hypothesis. Next-generation DNA methylation measures of biological aging developed to predict mortality risk and physiological decline are more predictive of morbidity and mortality than the original epigenetic clocks developed to predict chronological age. These new measures show consistent evidence of more advanced and faster biological aging in people exposed to socioeconomic disadvantage and may be able to record the emergence of socially determined health inequalities as early as childhood. Next-generation DNA methylation measures of biological aging also indicate race/ethnic disparities in biological aging. More research is needed on these measures in samples of non-Western and non-White populations. New DNA methylation measures of biological aging open opportunities for refining inference about the causes of social disparities in health and devising policies to eliminate them. Further refining measures of biological aging by including more diversity in samples used for measurement development is a critical priority for the field.