Relationship between five Epigenetic Clocks, Telomere Length and Functional Capacity assessed in Older Adults: Cross-sectional and Longitudinal Analyses

DNA methylation age acceleration (DNAmAA, derived from an epigenetic clock) and relative leukocyte telomere length (rLTL) are widely accepted biomarkers of aging. Nevertheless, it is still unclear which aspects of aging they represent best. Here we evaluated longitudinal associations between baseline rLTL and DNAmAA (estimated with 7-CpG clock) and functional assessments covering different domains of aging. Additionally, we made use of cross-sectional data on these assessments and examined their association with DNAmAA estimated by five different DNAm age measures. Two-wave longitudinal data was available for 1,083 participants of the Berlin Aging Study II (BASE-II) who were re-examined on average 7.4 years after baseline as part of the GendAge study. Functional outcomes were assessed with Fried’s frailty score, Tinetti mobility test, falls in the past 12 months (yes/no), Finger-floor distance, Mini Mental State Examination (MMSE), Center for Epidemiologic Studies Depression Scale (CES-D), Activities of Daily Living (ADL), Instrumented ADL (IADL) and Mini Nutritional Assessment (MNA). Overall, we found no evidence for an association between the molecular biomarkers measured at baseline, rLTL and DNAmAA (7-CpG clock), and functional assessments assessed at follow-up. Similarly, a cross-sectional analyses of follow-up data did also not show evidence for associations of the various DNAmAA measures (7-CpG clock, Horvath’s clock, Hannum’s clock PhenoAge, and GrimAge) with functional assessments. In conclusion, neither rLTL nor 7-CpG DNAmAA were able to predict impairment in the analyzed assessments over a ~7-year time-course. Similarly, DNAmAA estimated from five epigenetic clocks was not a good cross-sectional marker of health deterioration either.

Associations between Vitamin D, Omega 6:Omega 3 Ratio, and Biomarkers of Aging in Individuals Living with and without Chronic Pain

Elevated inflammatory cytokines and chronic pain are associated with shorter leukocyte telomere length (LTL), a measure of cellular aging. Micronutrients, such as 25-hydroxyvitamin D (vitamin D) and omega 3, have anti-inflammatory properties. Little is known regarding the relationships between vitamin D, omega 6:3 ratio, LTL, inflammation, and chronic pain. We investigate associations between vitamin D, omega 6:3 ratio, LTL, and C-reactive protein (CRP) in people living with/without chronic pain overall and stratified by chronic pain status. A cross-sectional analysis of 402 individuals (63% women, 79.5% with chronic pain) was completed. Demographic and health information was collected. Chronic pain was assessed as pain experienced for at least three months. LTL was measured in genomic DNA isolated from blood leukocytes, and micronutrients and CRP were measured in serum samples. Data were analyzed with general linear regression. Although an association between the continuous micronutrients and LTL was not observed, a positive association between omega 6:3 ratio and CRP was detected. In individuals with chronic pain, based on clinical categories, significant associations between vitamin D, omega 6:3 ratio, and CRP were observed. Findings highlight the complex relationships between anti-inflammatory micronutrients, inflammation, cellular aging, and chronic pain.

Creation of a collection of different biological sample types from elderly patients to study the relationship of clinical, systemic, tissue and cellular biomarkers of accumulation of senescent cells during aging

With aging, tissue homeostasis and their effective recovery after damage is violated. It has been shown that this may be due to the excessive accumulation of senescent (SC) cells in various tissues, which leads to the activation of chronic sterile inflammation, tissue dysfunction and, as a result, to the development of age-related diseases. To assess the contribution of SC cells to human body aging and pathogenesis of such diseases, relevant biomarkers are studied. For successful translation into clinical practice of approaches aimed at regulating the SC cell content in various tissues, it is necessary to study the relationship between the established clinical biomarkers of aging and age-related diseases, systemic aging parameters, and SC biomarkers at the tissue and cellular levels.Aim. To develop and describe action algorithms for creating a biobank of samples obtained from patients aged >65 years in order to study biomarkers of SC cell accumulation.Material and methods. To collect samples, an interaction system was built between several research, clinical and infrastructure departments of a multidisciplinary medical center. At the stage of preanalytical training, regulatory legal acts were developed, including informed consent for patients, as well as protocols for each stage of the study.Results. A roadmap was formed with action algorithms for all participants in the study, as well as with a convenient and accessible system of annotations and storage of biological samples. To date, the collection includes biological samples of 7 different types (peripheral blood serum, formalin-fixed tissue samples and formalin fixed paraffin embedded tissue specimens, samples of different cells isolated from peripheral blood, skin and adipose tissue, samples of deoxyribonucleic and ribonucleic acids, cell secretome conditioned media) obtained from 82 patients. We accumulated relevant anamnestic, clinical and laboratory data, as well as the results of experimental studies to assess the SC cell biomarkers. Using the collection, the relationship between clinical, tissue and cellular biomarkers of SC cell accumulation was studied.Conclusion. The creation of a collection of biological samples at the molecular, cellular, tissue and organism levels from one patient provides great opportunities for research in the field of personalized medicine and the study of age-related disease pathogenesis.

The Cross-Talk between Myeloid and Mesenchymal Stem Cells of Human Bone Marrow Represents a Biomarker of Aging That Regulates Immune Response and Bone Reabsorption

One of the mechanisms that characterizes the aging process of different organs is the accumulation of fat. Different authors have demonstrated that adipose tissue replaces the loss of other cell types, deriving from mesenchymal cells. During aging, there is substitution or trans-differentiation of mesenchymal cells with other cells having the same embryological origin. Newly formed adipocytes were also observed in the trabecular matrix of elderly people’s bones, associated with myeloid cells. In this study, we have investigated the relationship between immature myeloid-derived suppressor cells (I-MDSCs) and mesenchymal stem cells (MSCs) in bone marrow (BM) samples harvested from 57 patients subjected to different orthopedic surgeries. Patients aged from 18 to 92 years were considered in order to compare the cellular composition of bone marrow of young and elderly people, considered a biomarker of immunity, inflammation, and bone preservation. The I-MDSC percentage was stable during aging, but in elderly people, it was possible to observe a strong basal immunosuppression of autologous and heterologous T cells’ proliferation. We hypothesized that this pattern observed in elders depends on the progressive accumulation in the BM of activating stimuli, including cell–cell contact, or the production of different cytokines and proteins that induce the differentiation of bone marrow mesenchymal stem cells in adipocytes. The collected data provided underline the importance of specific biomarkers of aging that promote a reduction in immune response and incremented inflammatory pathways, leading to bone reabsorption in elderly people.

Approaching Multimorbidity From a Translational Geroscience Perspective

Multimorbidity describes the accumulated burden of chronic disease. Multimorbidity erodes physiologic reserve, increasing the risk of frailty, disability and death. Most older adults have at least one chronic health condition by age 65. Once established, many age-related conditions progress and accumulate with age. Geroscience holds that there are key biologic pathways that explain the increase with age in multimorbidity, frailty and disability Translation of geroscience principles to human studies requires careful assessment of biomarkers of these pathways and multisystem outcomes. In this symposium, translational researchers in geriatric medicine and gerontology will present current work to elucidate biologic underpinnings of aging and potential intervention targets. We will address whether blood biomarkers of aging processes are prognostic using combinatorial techniques and explore the potential for proteomics to identify novel pathways for health aging. New insights into the role of inflammation will be discussed with an emphasis on its relationship to multimorbidity. Brain aging will be considered with respect to the interactions between external stressors and resilience evaluating the role of ketone bodies which have immunomodulatory effects particularly on innate immune cells. Finally, the role of multimorbidity as an intervention target and potential intermediate outcomes including biomarkers will be presented with discussion of next steps needed to realize the potential for translational geroscience clinical trials to improve health span.

Physical Indicators of Aging are Related to Cellular Senescence Signal P16INK4a in Midlife Adults

Cellular senescence signal p16INK4a has been identified as a biomarker of aging that accumulates with chronological age across several tissues in mice and humans and may be potentially modifiable by interventions. This study examined whether physical indicators of aging were associated with p16INK4a and other markers of the aging process in midlife adults. Participants were 543 adults aged 26–78 years (Mage=54.0; 50.5% female) in the Midlife in the United States Refresher cohort. Interviews, questionnaires, and performance tests measured physical indicators of aging, including the Fried frailty index, limitations in daily activities, and age-related comorbidities. RNA sequencing of whole blood assessed biomarkers of aging: p16INK4a (CDKN2A), the DNA damage response (DDR), and the senescence-associated secretory phenotype (SASP). Older age was associated with enhanced p16INK4a (r=.11, p=.01), DDR (r=.34, p<.001), and SASP (r=.38, p<.001) expression. Multiple regression models that adjusted for age, sex, race/ethnicity, BMI, comorbidities, and time between assessments revealed that frailty (pre-frail/frail vs. non-frail) was associated with greater p16INK4a (B=0.13, p=.048) and marginally greater DDR (B=0.06, p=.06) expression. Limitations in daily activities were also associated with p16INK4a (B=0.12, p=.045). History of heart disease, stroke, arthritis, and cancer were associated with DDR and SASP expression in unadjusted models only (ps<.05). In summary, senescence indicator p16INK4a was elevated in whole blood samples from middle-aged adults who showed signs of frailty and limitations in daily activities. Findings suggest that whole blood p16INK4a expression might potentially be used to detect early signs of aging and target interventions to reduce biological aging and frailty.

Using Threshold Regression as an Approach to Incorporate Informative Missingness in Long Life Family Study Data

Genetics of aging is important since aging is a major risk factor in most diseases. Variables describing physiological state and cognitive functioning that influence morbidity and mortality risks can serve as biomarkers of aging. They change with increasing age and the ways in which these variables change can also influence these risks. Missing data due to dropout or death create problems in longitudinal studies producing biased results especially if the gap between exams is relatively long, as is the case in the Long Life Family Study (LLFS). We applied the threshold regression model to LLFS data to investigate the vitality and its rate, which are conceptualized as latent variables characterizing health and longevity, and to cope with such a problem. We performed genome-wide association study by sex and age groups to discover genetic signals on these phenotypes. We found 11 variants from the DACT2 gene, p-values < 1E-6 and variants rs12151399 (p-value = 8.43E-8, intron variant, gene AGAP1, in females), rs27958 (p-value = 8.39E-8, intron variant, gene ARHGAP26, in males) showing associations with the vitality. Olfactory receptors showed significant enrichment among the group of males over 80 years for the rate of aging phenotype. Results showed that vitality and its rate differ among sex and age groups. This work is an important step toward understanding the processes of aging linking the vitality with individual genetics using data from deceased and living individuals.

Operationalizing Healthspan as an Outcome for Clinical Trials in Geroscience

Efforts targeting biological aging pathways are advancing interventions which could extend healthy lifespan. Design of clinical trials to test such interventions necessitates an operational definition of healthspan, such as slowed accumulation or progression of multiple chronic diseases, functional decline, and disability. In this talk we explore these composite measures of healthspan proposed as outcomes for clinical trials in aging. This will be examined in example cases including multimorbidity and deficit accumulation frailty indices in an 8-Year intensive lifestyle intervention trial, and an update on multimordbity, functional, and biomarker endpoints in the trial Targeting Aging with MEtformin (TAME). Through these examples we will explore issues related to effect sizes and statistical challenges related to composite endpoints. Finally, we will discuss the role existing and emerging biomarkers of aging in clinical trials in geroscience and summarize evidence linking biomarkers to clinically meaningful outcomes.

A DNAmCULTURE Epigenetic Fingerprint Recapitulates Physiological Aging

Aging elicits dramatic changes to DNA methylation (DNAm), however the causes and consequences of such alterations to the epigenome remain unclear. The utility of biomarkers of aging based on DNAm patterns would be greatly enhanced if in vitro models existed that recapitulated physiological phenotypes such that modulation could garnish mechanistic insights. Using DNAm from serially passaged mouse embryonic fibroblasts, we developed a marker of culture aging and asked if culture phenotypes, like exhaustive replication, are epigenetically analogous to physiological aging. Our measure, termed DNAmCULTURE, accurately estimated passage number and was shown to strongly increase with age when examined in multiple tissues. Furthermore, we observed epigenetic alterations indicative of early cultured cells in animals undergoing caloric restriction and in lung and kidney fibroblasts re-programmed to iPSCs. This study identifies culture-derived alterations to the methylome as physiologically relevant and implicates culture aging as an important feature in known epigenetic aging phenomena.

Aging Biomarkers for Clinical Trials and Drug Discovery

Developing targeted therapies first requires a working definition of the condition of interest. Unfortunately for aging, this very initial step poses a challenge since chronological age is often not indicative of biological age nor modifiable. This symposium will demonstrate the enormous progress being made towards developing more reliable and valid measures for quantifying biological aging. First, Dr. Albert T. Higgins Chen will show how inaccuracy caused by noise at individual CpG sites can lead to high technical variability in the most widely applied biomarkers of aging—epigenetic clocks. He will further discuss how this can be overcome through novel statistical techniques. Second, Dr. Benoit Lehallier, will discuss plasma proteomic clocks and share insights into their potential roles in Alzheimer's disease and utilization in clinical trials. Third, quantifying the multifactorial aging process can be facilitated by projects incorporating multimodal biomarker data. Pei-Lun Kuo from the Baltimore Longitudinal Study of Aging will present an analysis of longitudinal trajectories of more than 30 phenotypes, which when combined into a single summarized score yield important insights. Fourth, our ability to uncover aging mechanisms and perform drug screens, requires valid and reliable measures that can be applied in vitro. Christopher Minteer who developed in cellulo epigenetic markers will demonstarte how epigenetic aging changes that can be induced in culture shed light on aging in vivo. Finally, a summarizing discussion will be held by Dr. Nir Barzilai, an expert in the field, who is leading the Targeting Aging with Metformin (TAME) clinical trial.