Exploring the Causal Pathway From Telomere Length to Coronary Heart Disease

Paternal Age and Transgenerational Telomere Length Maintenance: A Simulation Model

Telomere length (TL) in offspring is positively correlated with paternal age at the time of the offspring conception. The paternal-age-at-conception (PAC) effect on TL is puzzling, and its biological implication at the population level is unknown. Using a probabilistic model of transgenerational TL and population dynamics, we simulated the effect of PAC on TL in individuals over the course of 1,000 years. Findings suggest a key role for an isometric PAC midpoint (PACmp) in modulating TL across generations, such that offspring conceived by males younger than the isometric PACmp have comparatively short telomeres, while offspring conceived by males older than the isometric PACmp have comparatively long telomeres. We further show that when cancer incidence escalates, the average PAC drops below the isometric PACmp and transgenerational adaptation to cancer ensues through TL shortening. We propose that PAC serves to maintain an optimal TL across generations.

Cardiac-Referenced Leukocyte Telomere Length and Outcomes After Cardiovascular Surgery

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Short leukocyte telomeres have been associated with adverse cardiovascular outcomes in population studies, but this relationship has not translated to patient care. The authors report a telomere length autologous referencing strategy that has the potential to mark biological aging and to identify high-risk individuals.

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Among 163 patients who underwent cardiovascular surgery, telomeres in leukocytes and skeletal muscle displayed age-related shortening, whereas the telomere length in the cardiac right atrium was stable during 6 decades of life.

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The magnitude of the telomere length gap between cardiac atrial tissue and leukocytes was associated with post-operative complications and length of stay in the intensive care unit.

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This study provided proof of concept that a single-time, internally referenced assessment of leukocyte telomere shortening behavior could inform acute risks in patients with cardiovascular disease.

Leukocyte telomere shortening reflects stress burdens and has been associated with cardiac events. However, the patient-specific clinical value of telomere assessment remains unknown. Moreover, telomere shortening cannot be inferred from a single telomere length assessment. The authors investigated and developed a novel strategy for gauging leukocyte telomere shortening using autologous cardiac atrial referencing. Using multitissue assessments from 163 patients who underwent cardiovascular surgery, we determined that the cardiac atrium-leukocyte telomere length difference predicted post-operative complexity. This constituted the first evidence that a single-time assessment of telomere dynamics might be salient to acute cardiac care.

Leukocyte Telomere Length and All-Cause Mortality: A Between-Within Twin Study With Time-Dependent Effects Using Generalized Survival Models

Although previous studies examining leukocyte telomere length (LTL) and all-cause mortality controlled for several confounders, the observed association could be biased due to unmeasured confounders, including familial factors. We aimed to examine the association of LTL with all-cause mortality in a Swedish twin sample while adjusting for familial factors and allowing for time-dependent effects. A total of 366 participants (174 twin pairs and 18 individuals) were recruited from the Swedish Twin Registry. LTL was assessed using the Southern blot method. All-cause mortality data were obtained through linkage with the Swedish Population Registry, updated through November 15, 2017. To control for familial factors within twin pairs, we applied a between-within shared frailty model based on generalized survival models. Overall, 115 (31.4%) participants were men and 251 (68.6%) were women. The average age of the study participants when blood was drawn was 79.1 years, and follow-up duration ranged from 10 days to 25.7 years (mean = 10.2 years). During the follow-up period, 341 (93.2%) participants died. Shorter LTL was associated with higher mortality rates when controlling for familial factors in the between-within shared frailty model. We found significant time-dependent effects of LTL on all-cause mortality, where the mortality rate ratios were attenuated with increasing age.

Telomere length measurement as a clinical biomarker of aging and disease

Telomere length measurement is increasingly recognized as a clinical gauge for age-related disease risk. There are several methods for studying blood telomere length (BTL) as a clinical biomarker. The first is an observational study approach, which directly measures telomere lengths using either cross-sectional or longitudinal patient cohorts and compares them to a population of age- and sex-matched individuals. These direct traceable measurements can be considered reflective of an individual's current health or disease state. Escalating interest in personalized medicine, access to high-throughput genotyping and resulting acquisition of large volumes of genetic data corroborates the second method, Mendelian randomization (MR). MR employs telomere length-associated genetic variants to indicate predisposition to disease risk based on the genomic composition of the individual. When assessed from cells in the bloodstream, telomeres can show variation from their genetically predisposed lengths due to environmental-induced changes. These alterations in telomere length act as an indicator of cellular health, which, in turn, can provide disease risk status. Overall, BTL measurement is a dynamic marker of biological health and well-being that together with genetically defined telomere lengths can provide insights into improved healthcare for the individual.

Weight Loss Maintenance and Cellular Aging in the Supporting Health Through Nutrition and Exercise Study

OBJECTIVE

The aim of the study was to determine, within a weight loss clinical trial for obesity, the impact of intervention arm, weight change, and weight loss maintenance on telomere length (TL).

METHODS

Adults (N = 194) with a body mass index between 30 and 45 were randomized to a 5.5-month weight loss program with (n = 100) or without (n = 94) mindfulness training and identical diet-exercise guidelines. We assessed TL at baseline and 3-, 6-, and 12-month postbaseline in immune cell populations (primarily in peripheral blood mononuclear cells [PBMCs], but also in granulocytes and T and B lymphocytes). We defined weight loss maintenance as having lost at least 5% or 10% of body weight (tested in separate models) from preintervention to postintervention, and having maintained this loss at 12 months. We predicted that greater weight loss and weight loss maintenance would be associated with TL lengthening.

RESULTS

Neither weight loss intervention significantly predicted TL change nor did amount of weight change, at any time point. Across all participants, weight loss maintenance of at least 10% was associated with longer PBMC TL (b = 239.08, 95% CI = 0.92 to 477.25, p = .049), CD8+ TL (b = 417.26, 95% CI = 58.95 to 775.57, p = .023), and longer granulocyte TL (b = 191.56, 95% CI = -4.23 to 387.35, p = .055) at 12 months after accounting for baseline TL. Weight loss maintenance of 5% or more was associated with longer PBMC TL (b = 163.32, 95% CI = 4.00 to 320.62, p = .045) at 12 months after accounting for baseline TL. These tests should be interpreted in light of corrections for multiple tests.

CONCLUSIONS

Among individuals with obesity, losing and maintaining a weight loss of 10% or more may lead to TL lengthening, which may portend improved immune and metabolic function. TL lengthening in this study is of unknown duration beyond 12 months and requires further study.

TRIAL REGISTRATION

Clinicaltrials.govidentifierNCT00960414; Open Science Framework (OSF) preregistration: https://osf.io/t3r2g/.

Association of telomere length with general cognitive trajectories: a meta-analysis of four prospective cohort studies

To investigate the association of telomere length (TL) with trajectories of general cognitive abilities, we used data on 5955 participants from the Sex Differences in Health and Aging Study and the Swedish Adoption/Twin Study of Aging in Sweden, and the Mayo Clinic Study of Aging, and the Health and Retirement Study in the United States. TL was measured at baseline, while general cognitive ability was assessed repeatedly up to 7 occasions. Latent growth curve models were used to examine the associations. One standard deviation increase of TL was associated with 0.021 unit increase (95% confidence interval [CI]: 0.001, 0.042) of standardized mean general cognitive ability. After controlling for sex, the point estimate remained similar (0.019) with a wider CI (95% CI: -0.002, 0.039). The association was attenuated with adjustment for educational attainment (0.009, 95% CI: -0.009, 0.028). No strong evidence was observed for the association of TL and decline in general cognitive ability. Longer TL was associated with higher general cognitive ability levels in the age-adjusted models but not in the models including all covariates, nor with cognitive decline.

Actin Dynamics Couples Extracellular Signals to the Mobility and Molecular Stability of Telomeres

Genome regulatory programs such as telomere functioning require extracellular signals to be transmitted from the microenvironment to the nucleus and chromatin. Although the cytoskeleton has been shown to directly transmit stresses, we show that the intrinsically dynamic nature of the actin cytoskeleton is important in relaying extracellular signals to telomeres. Interestingly, this mechanical pathway not only transmits physical stimuli but also chemical stimuli. The cytoskeletal network continuously reorganizes and applies dynamic forces on the nucleus and feeds into the regulation of telomere dynamics. We further found that distal telomeres are mechanically coupled in a length- and timescale-dependent manner and identified nesprin 2G as well as lamin A/C as being essential to regulate their translational dynamics. Finally, we demonstrated that such mechanotransduction events impinge on the binding dynamics of critical telomere binding proteins. Our results highlight an overarching physical pathway that regulates positional and molecular stability of telomeres.

Insight meditation and telomere biology: The effects of intensive retreat and the moderating role of personality

A growing body of evidence suggests that meditation training may have a range of salubrious effects, including improved telomere regulation. Telomeres and the enzyme telomerase interact with a variety of molecular components to regulate cell-cycle signaling cascades, and are implicated in pathways linking psychological stress to disease. We investigated the effects of intensive meditation practice on these biomarkers by measuring changes in telomere length (TL), telomerase activity (TA), and telomere-related gene (TRG) expression during a 1-month residential Insight meditation retreat. Multilevel analyses revealed an apparent TL increase in the retreat group, compared to a group of experienced meditators, similarly comprised in age and gender, who were not on retreat. Moreover, personality traits predicted changes in TL, such that retreat participants highest in neuroticism and lowest in agreeableness demonstrated the greatest increases in TL. Changes observed in TRGs further suggest retreat-related improvements in telomere maintenance, including increases in Gar1 and HnRNPA1, which encode proteins that bind telomerase RNA and telomeric DNA. Although no group-level changes were observed in TA, retreat participants' TA levels at post-assessment were inversely related to several indices of retreat engagement and prior meditation experience. Neuroticism also predicted variation in TA across retreat. These findings suggest that meditation training in a retreat setting may have positive effects on telomere regulation, which are moderated by individual differences in personality and meditation experience. (ClinicalTrials.gov #NCT03056105).

Telomerase Mediates Lymphocyte Proliferation but Not the Atherosclerosis-Suppressive Potential of Regulatory T-Cells

Supplemental Digital Content is available in the text.

Objective—

Atherosclerosis is an age-related disease characterized by systemic oxidative stress and low-grade inflammation. The role of telomerase and telomere length in atherogenesis remains contentious. Short telomeres of peripheral leukocytes are predictive for coronary artery disease. Conversely, attenuated telomerase has been demonstrated to be protective for atherosclerosis. Hence, a potential causative role of telomerase in atherogenesis is critically debated.

Approach and Results—

In this study, we used multiple mouse models to investigate the regulation of telomerase under oxidative stress as well as its impact on atherogenesis in vitro and in vivo. Using primary lymphocytes and myeloid cell cultures, we demonstrate that cultivation under hyperoxic conditions induced oxidative stress resulting in chronic activation of CD4⁺ cells and significantly reduced CD4⁺ T-cell proliferation. The latter was telomerase dependent because oxidative stress had no effect on the proliferation of primary lymphocytes isolated from telomerase knockout mice. In contrast, myeloid cell proliferation was unaffected by oxidative stress nor reliant on telomerase. Telomerase reverse transcriptase deficiency had no effect on regulatory T-cell (T_reg) numbers in vivo or suppressive function ex vivo. Adoptive transfer of telomerase reverse transcriptase^–/– T_regs into Rag2^–/– ApoE^–/– (recombination activating gene 2/apolipoprotein E) double knockout mice demonstrated that telomerase function was not required for the ability of T_regs to protect against atherosclerosis. However, telomere length was critical for T_reg function.

Conclusions—

Telomerase contributes to lymphocyte proliferation but plays no major role in T_reg function, provided that telomere length is not critically short. We suggest that oxidative stress may contribute to atherosclerosis via suppression of telomerase and acceleration of telomere attrition in T_regs.

Stress, Telomeres, and Psychopathology: Toward a Deeper Understanding of a Triad of Early Aging

Telomeres play an important part in aging and show relationships to lifetime adversity, particularly childhood adversity. Meta-analyses demonstrate reliable associations between psychopathology (primarily depression) and shorter telomere length, but the nature of this relationship has not been fully understood. Here, we review and evaluate the evidence for impaired telomere biology as a consequence of psychopathology or as a contributing factor, and the important mediating roles of chronic psychological stress and impaired allostasis. There is evidence for a triadic relationship among stress, telomere shortening, and psychiatric disorders that is positively reinforcing and unfolds across the life course and, possibly, across generations. We review the role of genetics and biobehavioral responses that may contribute to shorter telomere length, as well as the neurobiological impact of impaired levels of telomerase. These complex interrelationships are important to elucidate because they have implications for mental and physical comorbidity and, potentially, for the prevention and treatment of depression.

Dietary Copper Intake and Its Association With Telomere Length: A Population Based Study

Background: Telomere is regarded as the fundamental aspect of cellular aging and copper is recognized as one of the most essential trace elements. The role of dietary copper intake in telomere length maintenance is seldom examined. This study aims to investigate if telomere length is to be associated with daily dietary copper intake. Methods: We used epidemiological data from a large national population-based health and nutrition survey. Dietary intake was assessed during the 24-h period before the interview date when blood sample was collected. Telomere length was measured from blood leukocyte using PCR method. The relationship between telomere length and dietary copper intake was assessed using multivariable linear regression models. We also examined if obesity, measured by body mass index, could modify the observed association. Results: There are 7,324 participants had both leukocyte telomere length measured and dietary copper intake assessed, around 48.0% of them were men. Telomere length was longer in women than that in men (1.05 ± 0.26 vs. 1.00 ± 0.26 T/S ratio), while dietary copper intake was less in women than that in men (1.12 ± 0.80 vs. 1.51 ± 1.61 mg). After controlling for age, sex, ethnicity, physical activity, current smoking status, hypertension, cardiovascular diseases, and body mass index in the multivariable linear regression models, one unit increase of log-transformed dietary copper intake was significantly associated with longer telomere length (β = 0.02, 95% confidence interval: 0.01, 0.04). We did not find a significant sex difference for this association. Conclusions: Dietary copper intake was significantly associated telomere length.The role of copper in human health might be involved in biological aging process.

Implication of Asana, Pranayama and Meditation on Telomere Stability

Telomeres, the repetitive sequences that protect the ends of chromosomes, help to maintain genomic integrity and are of key importance to human health. Telomeres progressively shorten throughout life and a number of studies have shown shorter telomere length to be associated with lifestyle disorders. Previous studies also indicate that yoga and lifestyle-based intervention have significant role on oxidative DNA damage and cellular aging. However, very few publications investigate telomere stability and its implication from the point of view of asana, pranayama, and meditation. In this context, a review was conducted to systematically assess the available data on the effectiveness of asana, pranayama, and meditation in maintaining telomere and telomerase. Literature search was performed using the following electronic databases: Cochrane Library, NCBI, PubMed, Google Scholar, EMBASE, and Web of Science. We explored the possible mechanisms of how asana, pranayama, and meditation might be affecting telomere length and telomerase. Moreover, results showed that asana and pranayama increase the oxygen flow to the cells and meditation reduces the stress level by modulating the hypothalamic–pituitary–adrenal axis. Summing up the result, it can be concluded that practice of asana, pranayama, and meditation can help to maintain genomic integrity and are of key importance to human health and lifestyle disorders.

Telomeres, Aging and Exercise: Guilty by Association?

Telomeres are repetitive tandem DNA sequences that cap chromosomal ends protecting genomic DNA from enzymatic degradation. Telomeres progressively shorten with cellular replication and are therefore assumed to correlate with biological and chronological age. An expanding body of evidence suggests (i) a predictable inverse association between telomere length, aging and age-related diseases and (ii) a positive association between physical activity and telomere length. Both hypotheses have garnered tremendous research attention and broad consensus; however, the evidence for each proposition is inconsistent and equivocal at best. Telomere length does not meet the basic criteria for an aging biomarker and at least 50% of key studies fail to find associations with physical activity. In this review, we address the evidence in support and refutation of the putative associations between telomere length, aging and physical activity. We finish with a brief review of plausible mechanisms and potential future research directions.

Longer Telomere Length and its Association with Lower Levels of C-Peptide

BACKGROUND

Telomeres undergo shortening with each cell division, which could be accelerated by increase obesity and is also related to endocrinology systems. In this study, we aimed to examine the complex association between telomere, C-peptide, and obesity as well as chronic inflammation in a large population-based cross-sectional survey.

METHODS

We used data from a community-based population study, where around 1,382 participants were recruited and had telomere length measured. The association of telomere length with C-peptide was studied using multiple linear regression models. We also examined if obesity, measured by body mass index (BMI), and inflammation could affect this observed association.

RESULTS

Around 48% of these participants were men and 52% were women. The average ages were 51.7 years old for men and 49.1 years old for women. After controlling for age and sex, 1 U increase of telomere length was associated with -0.17 (-0.28, -0.06) unit decrease of C-peptide. Additionally controlling for BMI, the association magnitude was decreased to -0.13 (-0.23, -0.04). Further adjusting for inflammation biomarker did not change the effect estimates.

CONCLUSION

Longer telomere was associated with lower levels of C-peptide. This association could be attenuated by adjusting for obesity.