Leukocyte telomere length and coronary artery calcium

Antiaging Strategies and Remedies: A Landscape of Research Progress and Promise

Aging is typified by a gradual loss of physiological fitness and accumulation of cellular damage, leading to deteriorated functions and enhanced vulnerability to diseases. Antiaging research has a long history throughout civilization, with many efforts put forth to understand and prevent the effects of aging. Multiple strategies aiming to promote healthy aging and extend the lifespan have been developed including lifestyle adjustments, medical treatments, and social programs. A multitude of antiaging medicines and remedies have also been explored. Here, we use data from the CAS Content Collection to analyze the publication landscape of recent research related to antiaging strategies and treatments. We review the recent advances and delineate trends in research headway of antiaging knowledge and practice across time, geography, and development pipelines. We further assess the state-of-the-art antiaging approaches and explore their correlations with age-related diseases. The landscape of antiaging drugs has been outlined and explored. Well-recognized and novel, currently evaluated antiaging agents have also been summarized. Finally, we review clinical applications of antiaging products with their development pipelines. The objective of this review is to summarize current knowledge on preventive strategies and treatment remedies in the field of aging, to outline challenges and evaluate growth opportunities, in order to further efforts to solve the problems that remain.

Role of angiotensin II in aging

Aging is an inevitable progressive decline in physiological organ function that increases the chance of disease and death. The renin-angiotensin system (RAS) is involved in the regulation of vasoconstriction, fluid homeostasis, cell growth, fibrosis, inflammation, and oxidative stress. In recent years, unprecedented advancement has been made in the RAS study, particularly with the observation that angiotensin II (Ang II), the central product of the RAS, plays a significant role in aging and chronic disease burden with aging. Binding to its receptors (Ang II type 1 receptor - AT1R in particular), Ang II acts as a mediator in the aging process by increasing free radical production and, consequently, mitochondrial dysfunction and telomere attrition. In this review, we examine the physiological function of the RAS and reactive oxygen species (ROS) sources in detail, highlighting how Ang II amplifies or drives mitochondrial dysfunction and telomere attrition underlying each hallmark of aging and contributes to the development of aging and age-linked diseases. Accordingly, the Ang II/AT1R pathway opens a new preventive and therapeutic direction for delaying aging and reducing the incidence of age-related diseases in the future.

Therapeutic Antiaging Strategies

Aging constitutes progressive physiological changes in an organism. These changes alter the normal biological functions, such as the ability to manage metabolic stress, and eventually lead to cellular senescence. The process itself is characterized by nine hallmarks: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. These hallmarks are risk factors for pathologies, such as cardiovascular diseases, neurodegenerative diseases, and cancer. Emerging evidence has been focused on examining the genetic pathways and biological processes in organisms surrounding these nine hallmarks. From here, the therapeutic approaches can be addressed in hopes of slowing the progression of aging. In this review, data have been collected on the hallmarks and their relative contributions to aging and supplemented with in vitro and in vivo antiaging research experiments. It is the intention of this article to highlight the most important antiaging strategies that researchers have proposed, including preventive measures, systemic therapeutic agents, and invasive procedures, that will promote healthy aging and increase human life expectancy with decreased side effects.

Comparison of Telomere Length between Buccal Cells and Blood Cells

Telomere length (TL) in blood cells is commonly used as a proxy for TL in other tissue types. The source of DNA of adequate quality and quantity is important for TL analysis. Compared to blood cells, buccal cells easy for genomic DNA preparation would facilitate the rapid and reliable TL analysis. However, the feasibility of buccal cells for TL analysis remains yet unestablished. We characterized TL of buccal cells and blood cells collected from 52 individuals using buccal cell swabs and fingertip sticks. Relative TL (RTL) determined by quantitative PCR showed that there is a strong correlation between buccal RTL and blood RTL (r=0.877, p<0.001), suggesting that buccal cells are adequate sources of DNA for TL analysis. The validity of sampling using buccal cell swabs provides simple operation and good reproducibility for TL analysis, that overcomes the discomfort and risk of infection caused by blood sampling.

The relationship between telomere length and putative markers of vascular ageing: A systematic review and meta-analysis

Accelerated biological aging contributes to the evolution of cardiovascular disease. However, its influence on subclinical organ damage remains unclear. Leukocyte telomere length (LTL) is emerging as a marker of biological cardiovascular aging. We performed a systematic review and meta-analysis to assess the association between LTL and measures of end-organ damage. PubMed, Medline, Embase, Cinahl Plus, ClinicalTrials.gov, and grey literature databases were searched for studies that assessed the association of LTL with arterial pulse wave velocity (aPWV), carotid intima-media thickness (cIMT), left ventricular mass (LVM or LVMI), renal outcomes, coronary artery calcium (CAC) and presence of carotid plaques. In a sample of 7256 patients, we found that cIMT (pooled correlation coefficient (r) = -0.249; 95 %CI -0.37, -0.128) and aPWV (pooled r = -0.194; 95 % CI -0.290, -0.100) inversely correlate with LTL. Compared to aPWV, cIMT had a stronger correlation with LTL. Patients without carotid plaques had longer telomeres than patients with carotid plaques. Quantitative analyses documented LTL association with renal outcomes and CAC, but not with LVM/LVMI. Among measures of end-organ damage, cIMT and aPWV provide the most accurate information on the contribution of biological aging to the process of vascular remodeling/damage.

The Ageing Brain: Molecular and Cellular Basis of Neurodegeneration

Ageing is an inevitable event in the lifecycle of all organisms, characterized by progressive physiological deterioration and increased vulnerability to death. Ageing has also been described as the primary risk factor of most neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and frontotemporal lobar dementia (FTD). These neurodegenerative diseases occur more prevalently in the aged populations. Few effective treatments have been identified to treat these epidemic neurological crises. Neurodegenerative diseases are associated with enormous socioeconomic and personal costs. Here, the pathogenesis of AD, PD, and other neurodegenerative diseases has been presented, including a summary of their known associations with the biological hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, cellular senescence, deregulated nutrient sensing, stem cell exhaustion, and altered intercellular communications. Understanding the central biological mechanisms that underlie ageing is important for identifying novel therapeutic targets for neurodegenerative diseases. Potential therapeutic strategies, including the use of NAD+ precursors, mitophagy inducers, and inhibitors of cellular senescence, has also been discussed.

Aging and the Biological Response to Liver Injury

Interest in understanding the aging process has recently risen in the scientific community. Aging, commonly defined as the functional decline in the function of organs and tissues, is indeed the major risk factor for the development of many chronic diseases, such as cardiovascular diseases, pathologies of nervous system, or cancer. To date, the influence of aging in the pathophysiology of liver and biliary diseases is not fully understood. Although liver cells have a high regenerative capacity, hepatocytes and cholangiocytes undergo extensive molecular changes in response to aging. Following time-dependent damage induced by aging, liver cells initially activate compensatory mechanisms that, if hyperstimulated, may lead to the decline of regenerative capacity and the development of pathologies. A deeper understanding of molecular aging has undoubtedly the potential to improve the clinical management of patients, possibly unveiling new pathways for selective drug treatment.

Genome-Protecting Compounds as Potential Geroprotectors

Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.

Aging-Related Molecular Pathways in Chronic Cholestatic Conditions

Aging is commonly defined as the time-dependent functional decline of organs and tissues. Average life expectancy has increased considerably over the past century and is estimated to increase even further, consequently also the interest in understanding the aging processes. Although aging is not a disease, it is the major risk factor for the development of many chronic diseases. Pathologies, such as Primary Biliary Cholangitis (PBC) and Primary Sclerosing Cholangitis (PSC) are cholestatic liver diseases characterized by chronic inflammation, biliary damage and ultimately liver fibrosis, targeting specifically cholangiocytes. To date, the influence of aging in these biliary diseases is not fully understood. Currently, liver transplantation is the only solution because of lacking in efficiently therapies. Although liver cells have a high regenerative capacity, they undergo extensive molecular changes in response to aging. Following time-dependent damage induced by aging, the cells initially activate protective compensatory processes that, if hyperstimulated, can lead to the decline of regenerative ability and the development of pathologies. Recent studies have introduced novel therapeutic tools for cholangiopathies that have showed to have promising potential as novel therapies for PSC and PBC and for the development of new drugs. The recent advancements in understanding of molecular aging have undoubtedly the potential to unveil new pathways for selective drug treatments, but further studies are needed to deepen their knowledge.

Changes of the coronary arteries and cardiac microvasculature with aging: Implications for translational research and clinical practice

Aging results in functional and structural changes in the cardiovascular system, translating into a progressive increase of mechanical vessel stiffness, due to a combination of changes in micro-RNA expression patterns, autophagy, arterial calcification, smooth muscle cell migration and proliferation. The two pivotal mechanisms of aging-related endothelial dysfunction are oxidative stress and inflammation, even in the absence of clinical disease. A comprehensive understanding of the aging process is emerging as a primary concern in literature, as vascular aging has recently become a target for prevention and treatment of cardiovascular disease. Change of life-style, diet, antioxidant regimens, anti-inflammatory treatments, senolytic drugs counteract the pro-aging pathways or target senescent cells modulating their detrimental effects. Such therapies aim to reduce the ineluctable burden of age and contrast aging-associated cardiovascular dysfunction. This narrative review intends to summarize the macrovascular and microvascular changes related with aging, as a better understanding of the pathways leading to arterial aging may contribute to design new mechanism-based therapeutic approaches to attenuate the features of vascular senescence and its clinical impact on the cardiovascular system.

Prenatal and Childhood Traffic-Related Air Pollution Exposure and Telomere Length in European Children: The HELIX Project

BACKGROUND

Telomere length is a molecular marker of biological aging.

OBJECTIVE

Here we investigated whether early-life exposure to residential air pollution was associated with leukocyte telomere length (LTL) at 8 y of age.

METHODS

In a multicenter European birth cohort study, HELIX (Human Early Life Exposome) ([Formula: see text]), we estimated prenatal and 1-y childhood exposure to nitrogen dioxide ([Formula: see text]), particulate matter with aerodynamic diameter [Formula: see text] ([Formula: see text]), and proximity to major roads. Average relative LTL was measured using quantitative real-time polymerase chain reaction (qPCR). Effect estimates of the association between LTL and prenatal, 1-y childhood air pollution, and proximity to major roads were calculated using multiple linear mixed models with a random cohort effect and adjusted for relevant covariates.

RESULTS

LTL was inversely associated with prenatal and 1-y childhood [Formula: see text] and [Formula: see text] exposures levels. Each standard deviation (SD) increase in prenatal [Formula: see text] was associated with a [Formula: see text] (95% CI: [Formula: see text], [Formula: see text]) change in LTL. Prenatal [Formula: see text] was nonsignificantly associated with LTL ([Formula: see text] per SD increase; 95% CI: [Formula: see text], 0.6). For each SD increment in 1-y childhood [Formula: see text] and [Formula: see text] exposure, LTL shortened by [Formula: see text] (95% CI: [Formula: see text], [Formula: see text]) and [Formula: see text] (95% CI: [Formula: see text], 0.1), respectively. Each doubling in residential distance to nearest major road during childhood was associated with a 1.6% (95% CI: 0.02, 3.1) lengthening in LTL.

CONCLUSION

Lower exposures to air pollution during pregnancy and childhood were associated with longer telomeres in European children at 8 y of age. These results suggest that reductions in traffic-related air pollution may promote molecular longevity, as exemplified by telomere length, from early life onward. https://doi.org/10.1289/EHP4148.

Telomere length and health outcomes: An umbrella review of systematic reviews and meta-analyses of observational studies

The aim of the present study was to map and grade evidence for the relationships between telomere length with a diverse range of health outcomes, using an umbrella review of systematic reviews with meta-analyses. We searched for meta-analyses of observational studies reporting on the association of telomere length with any health outcome (clinical disease outcomes and intermediate traits). For each association, random-effects summary effect size, 95% confidence interval (CI), and 95% prediction interval were calculated. To evaluate the credibility of the identified evidence, we assessed also heterogeneity, evidence for small-study effect and evidence for excess significance bias. Twenty-one relevant meta-analyses were identified reporting on 50 different outcomes. The level of evidence was high only for the association of short telomeres with higher risk of gastric cancer in the general population (relative risk, RR = 1.95, 95%CI: 1.68-2.26), and moderate for the association of shorter telomeres with diabetes or with Alzheimer's disease, even if limited to meta-analyses of case-control studies. There was weak evidence for twenty outcomes and not significant association for 27 health outcomes. The present umbrella review demonstrates that shorter telomere length may have an important role in incidence gastric cancer and, probably, diabetes and Alzheimer's disease. At the same time, conversely to general assumptions, it does not find strong evidence supporting the notion that shorter telomere length plays an important role in many health outcomes that have been studied thus far.

Telomere length and age-dependent telomere attrition: the blood-and-muscle model

Short telomere length (TL) is associated with atherosclerotic cardiovascular disease (ACVD) and other age-related diseases. It is unclear whether these associations originate from having inherently short TL or a faster TL attrition before or during disease development. We proposed the blood-and-muscle model to assess TL dynamics throughout life course. Our objective was to measure TL in leukocytes (LTL) and in skeletal muscle (MTL), which served as a proxy of TL at birth. The delta (MTL–LTL) represented life-long telomere attrition. Blood draws and skeletal muscle biopsies were performed on 35 Lebanese individuals undergoing surgery. Following DNA extraction, LTL and MTL were measured by Southern blot. In every individual aged between 30 and 85 years, MTL was longer than LTL. With age, MTL and LTL decreased, but the delta (MTL–LTL) increased by 14 bp/year. We validated the blood-and-muscle model that allowed us to identify TL, TL at birth, and lifelong TL attrition in a cross-sectional study. This model can be used in larger cross-sectional studies to evaluate the association of telomere dynamics with age-related diseases onset and progression.

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.

Retinal microcirculation and leukocyte telomere length in the general population

Retinal arteriolar narrowing increases with age and predict adverse cardiovascular outcomes. Telomere length keeps track of the division of somatic cells and is a biomarker of biological age. We investigated to what extent retinal arteriolar diameters are associated with biological age, as captured by leukocyte telomere length (LTL). In 168 randomly selected Flemish participants from the family-based population study FLEMENGHO (mean age, 46.2 years) at baseline, of whom 85 underwent a follow-up examination (median, 4.1 years), we post-processed nonmydriatic retinal photographs and measured LTL. In men only, central retinal arteriolar equivalents (CRAE) and arteriole-to-venule ratio (AVR) were associated with LTL with stronger associations at higher age and body mass index. In men aged 57.6 years (75th percentile) a 20% shorter LTL was associated with a decrease in CRAE of 4.57 µm. A 20% shorter LTL was associated with a decrease of 5.88 µm in CRAE at a BMI of 29.9 kg/m2 (75th percentile). Similar associations were observed between AVR and LTL. In women, no retinal microvascular traits were associated with LTL. Retinal arteriolar narrowing in men but not in women is associated with biological age. Our findings support the idea that avoiding overweight contributes to maintaining a healthier microcirculation.

All-cause mortality in patients with basal and squamous cell carcinoma: A systematic review and meta-analysis

BACKGROUND

There are varying reports of the association of basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC) with mortality.

OBJECTIVE

To synthesize the available information on all-cause mortality after a diagnosis of BCC or SCC in the general population.

METHODS

We searched PubMed (1966-present), Web of Science (1898-present), and Embase (1947-present) and hand-searched to identify additional records. All English articles that reported all-cause mortality in patients with BCC or SCC were eligible. We excluded case reports, case series, and studies in subpopulations of patients. Random effects model meta-analyses were performed separately for BCC and SCC.

RESULTS

The searches yielded 6538 articles, and 156 were assessed in a full-text review. Twelve studies met the inclusion criteria, and 4 were included in the meta-analysis (encompassing 464,230 patients with BCC and with 175,849 SCC), yielding summary relative mortalities of 0.92 (95% confidence interval, 0.83-1.02) in BCC and 1.25 (95% confidence interval, 1.17-1.32) in SCC.

LIMITATIONS

Only a minority of studies controlled for comorbidities. There was significant heterogeneity in meta-analysis (χ2P < .001, I2 > 98%), but studies of SCC were qualitatively concordant: all showed statistically significant increased relative mortality.

CONCLUSIONS

We found that patients with SCC are at higher risk for death from any cause compared with the general population.

Prenatal Air Pollution and Newborns' Predisposition to Accelerated Biological Aging

IMPORTANCE

Telomere length is a marker of biological aging that may provide a cellular memory of exposures to oxidative stress and inflammation. Telomere length at birth has been related to life expectancy. An association between prenatal air pollution exposure and telomere length at birth could provide new insights in the environmental influence on molecular longevity.

OBJECTIVE

To assess the association of prenatal exposure to particulate matter (PM) with newborn telomere length as reflected by cord blood and placental telomere length.

DESIGN, SETTING, AND PARTICIPANTS

In a prospective birth cohort (ENVIRONAGE [Environmental Influence on Ageing in Early Life]), a total of 730 mother-newborn pairs were recruited in Flanders, Belgium between February 2010 and December 2014, all with a singleton full-term birth (≥37 weeks of gestation). For statistical analysis, participants with full data on both cord blood and placental telomere lengths were included, resulting in a final study sample size of 641.

EXPOSURES

Maternal residential PM2.5 (particles with an aerodynamic diameter ≤2.5 μm) exposure during pregnancy.

MAIN OUTCOMES AND MEASURES

In the newborns, cord blood and placental tissue relative telomere length were measured. Maternal residential PM2.5 exposure during pregnancy was estimated using a high-resolution spatial-temporal interpolation method. In distributed lag models, both cord blood and placental telomere length were associated with average weekly exposures to PM2.5 during pregnancy, allowing the identification of critical sensitive exposure windows.

RESULTS

In 641 newborns, cord blood and placental telomere length were significantly and inversely associated with PM2.5 exposure during midgestation (weeks 12-25 for cord blood and weeks 15-27 for placenta). A 5-µg/m3 increment in PM2.5 exposure during the entire pregnancy was associated with 8.8% (95% CI, -14.1% to -3.1%) shorter cord blood leukocyte telomeres and 13.2% (95% CI, -19.3% to -6.7%) shorter placental telomere length. These associations were controlled for date of delivery, gestational age, maternal body mass index, maternal age, paternal age, newborn sex, newborn ethnicity, season of delivery, parity, maternal smoking status, maternal educational level, pregnancy complications, and ambient temperature.

CONCLUSIONS AND RELEVANCE

Mothers who were exposed to higher levels of PM2.5 gave birth to newborns with shorter telomere length. The observed telomere loss in newborns by prenatal air pollution exposure indicates less buffer for postnatal influences of factors decreasing telomere length during life. Therefore, improvements in air quality may promote molecular longevity from birth onward.

The Biology of Aging and Cancer: A Brief Overview of Shared and Divergent Molecular Hallmarks

Aging is the inevitable time-dependent decline in physiological organ function and is a major risk factor for cancer development. Due to advances in health care, hygiene control and food availability, life expectancy is increasing and the population in most developed countries is shifting to an increasing proportion of people at a cancer susceptible age. Mechanisms of aging are also found to occur in carcinogenesis, albeit with shared or divergent end-results. It is now clear that aging and cancer development either share or diverge in several disease mechanisms. Such mechanisms include the role of genomic instability, telomere attrition, epigenetic changes, loss of proteostasis, decreased nutrient sensing and altered metabolism, but also cellular senescence and stem cell function. Cancer cells and aged cells are also fundamentally opposite, as cancer cells can be thought of as hyperactive cells with advantageous mutations, rapid cell division and increased energy consumption, while aged cells are hypoactive with accumulated disadvantageous mutations, cell division inability and a decreased ability for energy production and consumption. Nonetheless, aging and cancer are tightly interconnected and many of the same strategies and drugs may be used to target both, while in other cases antagonistic pleiotrophy come into effect and inhibition of one can be the activation of the other. Cancer can be considered an aging disease, though the shared mechanisms underpinning the two processes remain unclear. Better understanding of the shared and divergent pathways of aging and cancer is needed.

Leukocyte telomere length and cardiovascular disease in African Americans: The Jackson Heart Study

BACKGROUND AND AIMS

In European descent populations, shorter leukocyte telomere length (LTL) has been associated with subclinical atherosclerosis, cardiovascular disease (CVD), and mortality, while longer LTL has been associated with greater left ventricular hypertrophy. We evaluated the relationship of LTL with subclinical cardiovascular disease indices and incident clinical events and mortality in African Americans (AAs).

METHODS

Analyses were restricted to 2518 participants of the Jackson Heart Study (JHS) with LTL measured by Southern blot in baseline blood samples.

RESULTS

Adjusting for established CVD risk factors, longer LTL was significantly associated with lower prevalence of coronary artery calcification (CAC) (odds ratio (OR) = 0.810) per 1 kb increase in LTL; (95% confidence interval [CI] 0.656, 0.9998), p=0.0498). Longer LTL was also associated with higher ankle brachial index (ABI) (β = 0.023; (95% CI 0.004, 0.042), p=0.017) when comparing the highest to the lowest LTL quartile. There were no significant associations between LTL and abdominal aortic calcification, carotid intima-media thickness, or left ventricular mass. After a median follow-up of 9 years, longer LTL was associated with lower risk of incident ischemic stroke (hazard ratio (HR) 0.69 (95% CI 0.48, 0.99), p=0.044) and total mortality (HR 0.81 (95% CI 0.67, 0.97), p=0.026) in age and sex adjusted models, but these associations were no longer significant in fully adjusted models.

CONCLUSIONS

Among a community-based cohort of AAs, longer LTL was nominally associated with lower odds of CAC and increased ABI, indicative of decreased prevalence of subclinical atherosclerosis and peripheral arterial disease. These findings do not offer strong support for LTL as an independent biomarker of CVD risk in AAs.

Shorter leukocyte telomere length is associated with higher risk of infections: a prospective study of 75,309 individuals from the general population

In the general population, older age is associated with short leukocyte telomere length and with high risk of infections. In a recent study of allogeneic hematopoietic cell transplantation for severe aplastic anemia, long donor leukocyte telomere length was associated with improved survival in the recipients. These findings suggest that leukocyte telomere length could possibly be a marker of immune competence. Therefore, we tested the hypothesis that shorter leukocyte telomere length is associated with higher risk of infectious disease hospitalization and infection-related death. Relative peripheral blood leukocyte telomere length was measured using quantitative polymerase chain reaction in 75,309 individuals from the general population and the individuals were followed for up to 23 years. During follow up, 9228 individuals were hospitalized with infections and infection-related death occurred in 1508 individuals. Shorter telomere length was associated with higher risk of any infection (hazard ratio 1.05 per standard deviation shorter leukocyte telomere length; 95% confidence interval 1.03–1.07) and pneumonia (1.07; 1.03–1.10) after adjustment for conventional infectious disease risk factors. Corresponding hazard ratios for infection-related death were 1.10 (1.04–1.16) for any infection and 1.11 (1.04–1.19) for pneumonia. Telomere length was not associated with risk of skin infection, urinary tract infection, sepsis, diarrheal disease, endocarditis, meningitis or other infections. In conclusion, our findings indicate that leukocyte telomere length may be a marker of immune competence. Further studies are needed to determine whether risk of infections in allogeneic hematopoietic cell transplantation recipients can be reduced by considering donor leukocyte telomere length when selecting donors.

Less Than Ideal Cardiovascular Health Is Associated With Shorter Leukocyte Telomere Length: The National Health and Nutrition Examination Surveys, 1999-2002

Background

The associations between individual cardiovascular disease risk factors and leukocyte telomere length (LTL) have been inconclusive. We investigated the association between LTL and overall cardiovascular health (CVH) as defined by the American Heart Association and whether the association is modified by sex and race/ethnicity.

Methods and Results

We included 5194 adults (aged ≥20) from the National Health and Nutrition Examination Survey 1999–2002. CVH was defined as a composite score of the 7 metrics (smoking, physical activity, diet, body mass index, blood pressure, total cholesterol, and fasting blood glucose) and categorized as “poor,” “intermediate,” and “ideal.” LTL was assayed from whole blood using the quantitative polymerase chain reaction method relative to standard reference DNA. Multivariable linear regression models were used to estimate the association between CVH and log‐transformed LTL. We found strong graded association between CVH and LTL in the overall sample, with evidence of dose‐response relationship (P for trend=0.013). Individuals with poor and intermediate CVH had significantly shorter LTL than individuals with ideal CVH (−3.4% [95% CI=−6.0%, −0.8%] and −2.4% [−4.4%, −0.3%], respectively), after adjustment for demographic variables, socioeconomic status, and C‐reactive protein. The association was stronger in women (−6.6% [−10.2%, −2.9%] for poor vs ideal CVH) and non‐Hispanic whites (−4.3% [−7.1%, −1.4%] for poor vs ideal CVH).

Conclusions

The findings suggest that less‐than‐ideal CVH is associated with shorter LTL, but this association varies by sex and race/ethnicity. Future longitudinal research is needed to elucidate the mechanisms that underlie the association between CVH and LTL.

Telomere Shortening, Regenerative Capacity, and Cardiovascular Outcomes

RATIONALE

Leukocyte telomere length (LTL) is a biological marker of aging, and shorter LTL is associated with adverse cardiovascular outcomes. Reduced regenerative capacity has been proposed as a mechanism. Bone marrow-derived circulating progenitor cells are involved in tissue repair and regeneration.

OBJECTIVE

Main objective of this study was to examine the relationship between LTL and progenitor cells and their impact on adverse cardiovascular outcomes.

METHODS AND RESULTS

We measured LTL by quantitative polymerase chain reaction in 566 outpatients (age: 63±9 years; 76% men) with coronary artery disease. Circulating progenitor cells were enumerated by flow cytometry. After adjustment for age, sex, race, body mass index, smoking status, and previous myocardial infarction, a shorter LTL was associated with a lower CD34⁺ cell count: for each 10% shorter LTL, CD34⁺ levels were 5.2% lower (P<0.001). After adjustment for the aforementioned factors, both short LTL (<Q1) and low CD34+ levels (<Q1) predicted adverse cardiovascular outcomes (death, myocardial infarction, coronary revascularization, or cerebrovascular events) independently of each other, with a hazard ratio of 1.8 and 95% confidence interval of 1.1 to 2.0, and a hazard ratio of 2.1 and 95% confidence interval of 1.3 to 3.0, respectively, comparing Q1 to Q2-4. Patients who had both short LTL (<Q1) and low CD34+ cell count (<Q1) had the greatest risk of adverse outcomes (hazard ratio =3.5; 95% confidence interval, 1.7-7.1).

CONCLUSIONS

Although shorter LTL is associated with decreased regenerative capacity, both LTL and circulating progenitor cell levels are independent and additive predictors of adverse cardiovascular outcomes in coronary artery disease patients. Our results suggest that both biological aging and reduced regenerative capacity contribute to cardiovascular events, independent of conventional risk factors.

Measuring the effects of CVD interventions and studies across socioeconomic groups: A brief review

There is a known socioeconomic skew in prevalence and outcomes of cardiovascular disease (CVD). To document the proportion of clinical trials and observational studies related to CVD recently published in peer-reviewed journals that report the socio-economic distributional differences in their outcomes. We undertook a review of peer-reviewed clinical trials and observational studies relating to CVD published between 01/06/2015-31/12/2015 in PubMed; and identified the proportion that included measures of socioeconomic status and the proportion that stratified results by, or controlled for, socioeconomic status when reporting outcomes. 414 peer reviewed publications reporting the outcomes of clinical trials or observational studies that related to CVD were identified. 32 of these reported on the socioeconomic status of participants. Of these, 20 stratified the results by socioeconomic status or adjusted the results for socioeconomic status. 18 studies measured education attainment, 5 measured income, 1 measured rurality and 1 measured occupation. Of the 414 articles reporting the outcomes of clinical trials or observational studies related to cardiovascular disease in 2015, the effectiveness of the intervention, or the differences in outcomes, between socioeconomic groups was assessed in 5% of studies. This lack of consideration of the effectiveness of trial outcomes or the differences in outcomes across socioeconomic groups impairs the ability of readers, healthcare professionals and policy makers to assess the impact of new treatments or interventions in closing the inequality gap associated with CVD.

Maternal pre-pregnancy body mass index and newborn telomere length

BACKGROUND

Newborn telomere length sets telomere length for later life. At birth, telomere length is highly variable among newborns and the environmental factors during in utero life for this observation remain largely unidentified. Obesity during pregnancy might reflect an adverse nutritional status affecting pregnancy and offspring outcomes, but the association of maternal pre-pregnancy body mass index (BMI) with newborn telomere length, as a mechanism of maternal obesity, on the next generation has not been addressed.

METHODS

Average relative telomere lengths were measured in cord blood (n = 743) and placental tissue (n = 702) samples using a quantitative real-time PCR method from newborns from the ENVIRONAGE birth cohort in Belgium. By using univariate and multivariable adjusted linear regression models we addressed the associations between pre-pregnancy BMI and cord blood and placental telomere lengths.

RESULTS

Maternal age was 29.1 years (range, 17-44) and mean (SD) pre-pregnancy BMI was 24.1 (4.1) kg/m². Decline in newborn telomere length occurred in parallel with higher maternal pre-pregnancy BMI. Independent of maternal and paternal age at birth, maternal education, gestational age, newborn gender, ethnicity, birthweight, maternal smoking status, parity, cesarean section, and pregnancy complications, each kg/m² increase in pre-pregnancy BMI was associated with a -0.50 % (95 % CI, -0.83 to -0.17 %; P = 0.003) shorter cord blood telomere length and a -0.66 % (95 % CI, -1.06 to -0.25 %; P = 0.002) shorter placental telomere length.

CONCLUSIONS

Maternal pre-pregnancy BMI is associated with shorter newborn telomere lengths as reflected by cord blood and placental telomeres. These findings support the benefits of a pre-pregnancy healthy weight for promoting molecular longevity from early life onwards.

Maternal pre-pregnancy body mass index and newborn telomere length

BACKGROUND

Newborn telomere length sets telomere length for later life. At birth, telomere length is highly variable among newborns and the environmental factors during in utero life for this observation remain largely unidentified. Obesity during pregnancy might reflect an adverse nutritional status affecting pregnancy and offspring outcomes, but the association of maternal pre-pregnancy body mass index (BMI) with newborn telomere length, as a mechanism of maternal obesity, on the next generation has not been addressed.

METHODS

Average relative telomere lengths were measured in cord blood (n = 743) and placental tissue (n = 702) samples using a quantitative real-time PCR method from newborns from the ENVIRONAGE birth cohort in Belgium. By using univariate and multivariable adjusted linear regression models we addressed the associations between pre-pregnancy BMI and cord blood and placental telomere lengths.

RESULTS

Maternal age was 29.1 years (range, 17-44) and mean (SD) pre-pregnancy BMI was 24.1 (4.1) kg/m². Decline in newborn telomere length occurred in parallel with higher maternal pre-pregnancy BMI. Independent of maternal and paternal age at birth, maternal education, gestational age, newborn gender, ethnicity, birthweight, maternal smoking status, parity, cesarean section, and pregnancy complications, each kg/m² increase in pre-pregnancy BMI was associated with a -0.50 % (95 % CI, -0.83 to -0.17 %; P = 0.003) shorter cord blood telomere length and a -0.66 % (95 % CI, -1.06 to -0.25 %; P = 0.002) shorter placental telomere length.

CONCLUSIONS

Maternal pre-pregnancy BMI is associated with shorter newborn telomere lengths as reflected by cord blood and placental telomeres. These findings support the benefits of a pre-pregnancy healthy weight for promoting molecular longevity from early life onwards.

Heart aging measured with coronary artery calcium scoring and cardiovascular risk assessment algorithms in HIV infected patients

ABTRACT Many sources have highlighted the high incidence of premature cardiovascular events in HIV infected patients. This raises the suspicion of an accelerated aging of the vascular system in this disease characterized by chronic systemic subliminal inflammation and immune dysregulation. Unfortunately all currently available risk assessment algorithms based on traditional risk factors, and even those containing more HIV-specific factors, fail to accurately predict risk in a large proportion of patients. In the general population several models have implemented imaging data to refine risk assessment, and the concept of vascular aging has been of value in improving the performance of these algorithms. It is expected that HIV patients may benefit from a similar approach as it becomes clearer that vascular imaging provides valuable prognostic information in this patient category.

Telomere Length and the Cancer-Atherosclerosis Trade-Off

Modern humans, the longest-living terrestrial mammals, display short telomeres and repressed telomerase activity in somatic tissues compared with most short-living small mammals. The dual trait of short telomeres and repressed telomerase might render humans relatively resistant to cancer compared with short-living small mammals. However, the trade-off for cancer resistance is ostensibly increased age-related degenerative diseases, principally in the form of atherosclerosis. In this communication, we discuss (a) the genetics of human telomere length, a highly heritable complex trait that is influenced by genetic ancestry, sex, and paternal age at conception, (b) how cancer might have played a role in the evolution of telomere biology across mammals, (c) evidence that in modern humans telomere length is a determinant (rather than only a biomarker) of cancer and atherosclerosis, and (d) the potential influence of relatively recent evolutionary forces in fashioning the variation in telomere length across and within populations, and their likely lasting impact on major diseases in humans. Finally, we propose venues for future research on human telomere genetics in the context of its potential role in shaping the modern human lifespan.

Molecular and biological hallmarks of ageing

BACKGROUND

Ageing is the inevitable time-dependent decline in physiological organ function that eventually leads to death. Age is a major risk factor for many of the most common medical conditions, such as cardiovascular disease, cancer, diabetes and Alzheimer's disease. This study reviews currently known hallmarks of ageing and their clinical implications.

METHODS

A literature search of PubMed/MEDLINE was conducted covering the last decade.

RESULTS

Average life expectancy has increased dramatically over the past century and is estimated to increase even further. Maximum longevity, however, appears unchanged, suggesting a universal limitation to the human organism. Understanding the underlying molecular processes of ageing and health decline may suggest interventions that, if used at an early age, can prevent, delay, alleviate or even reverse age-related diseases. Hallmarks of ageing can be grouped into three main categories. The primary hallmarks cause damage to cellular functions: genomic instability, telomere attrition, epigenetic alterations and loss of proteostasis. These are followed by antagonistic responses to such damage: deregulated nutrient sensing, altered mitochondrial function and cellular senescence. Finally, integrative hallmarks are possible culprits of the clinical phenotype (stem cell exhaustion and altered intercellular communication), which ultimately contribute to the clinical effects of ageing as seen in physiological loss of reserve, organ decline and reduced function.

CONCLUSION

The sum of these molecular hallmarks produces the clinical picture of the elderly surgical patient: frailty, sarcopenia, anaemia, poor nutrition and a blunted immune response system. Improved understanding of the ageing processes may give rise to new biomarkers of risk or prognosis, novel treatment targets and translational approaches across disciplines that may improve outcomes.

Leukocyte Telomere Length in Newborns: Implications for the Role of Telomeres in Human Disease

BACKGROUND AND OBJECTIVE

In adults, leukocyte telomere length (LTL) is variable, familial, and longer in women and in offspring conceived by older fathers. Although short LTL is associated with atherosclerotic cardiovascular disease, long LTL is associated with major cancers. The prevailing notion is that LTL is a "telomeric clock," whose movement (expressed in LTL attrition) reflects the pace of aging. Accordingly, individuals with short LTL are considered to be biologically older than their peers. Recent studies suggest that LTL is largely determined before adulthood. We examined whether factors that largely characterize LTL in adults also influence LTL in newborns.

METHODS

LTL was measured in blood samples from 490 newborns and their parents.

RESULTS

LTL (mean ± SD) was longer (9.50 ± 0.70 kb) in newborns than in their mothers (7.92 ± 0.67 kb) and fathers (7.70 ± 0.71 kb) (both P < .0001); there was no difference in the variance of LTL among the 3 groups. Newborn LTL correlated more strongly with age-adjusted LTL in mothers (r = 0.47; P < .01) than in fathers (r = 0.36; P < .01) (P for interaction = .02). Newborn LTL was longer by 0.144 kb in girls than in boys (P = .02), and LTL was longer by 0.175 kb in mothers than in fathers (P < .0001). For each 1-year increase in father's age, newborn LTL increased by 0.016 kb (95% confidence interval: 0.04 to 0.28) (P = .0086).

CONCLUSIONS

The large LTL variation across newborns challenges the telomeric clock model. Having inherently short or long LTL may be largely determined at birth, anteceding by decades disease manifestation in adults.

Shorter telomere length in Europeans than in Africans due to polygenetic adaptation

Leukocyte telomere length (LTL), which reflects telomere length in other somatic tissues, is a complex genetic trait. Eleven SNPs have been shown in genome-wide association studies to be associated with LTL at a genome-wide level of significance within cohorts of European ancestry. It has been observed that LTL is longer in African Americans than in Europeans. The underlying reason for this difference is unknown. Here we show that LTL is significantly longer in sub-Saharan Africans than in both Europeans and African Americans. Based on the 11 LTL-associated alleles and genetic data in phase 3 of the 1000 Genomes Project, we show that the shifts in allele frequency within Europe and between Europe and Africa do not fit the pattern expected by neutral genetic drift. Our findings suggest that differences in LTL within Europeans and between Europeans and Africans is influenced by polygenic adaptation and that differences in LTL between Europeans and Africans might explain, in part, ethnic differences in risks for human diseases that have been linked to LTL.

Leukocyte Telomere Length and Risks of Incident Coronary Heart Disease and Mortality in a Racially Diverse Population of Postmenopausal Women

OBJECTIVE

Telomeres are regions at the ends of chromosomes that maintain chromosomal structural integrity and genomic stability. In studies of mainly older, white populations, shorter leukocyte telomere length (LTL) is associated with cardiometabolic risk factors and increased risks of mortality and coronary heart disease (CHD). On average, African Americans (AfAm) have longer LTL than whites, but the LTL-CHD relationship in AfAm is unknown. We investigated the relationship of LTL with CHD and mortality among AfAm.

APPROACH AND RESULTS

Using a case-cohort design, 1525 postmenopausal women (667 AfAm and 858 whites) from the Women's Health Initiative had LTL measured in baseline blood samples by Southern blotting. CHD or mortality hazards ratios were estimated using race-stratified and risk factor-adjusted Cox proportional hazards models. There were 367 incident CHD (226 mortality) events in whites, whereas AfAm experienced 269 incident CHD (216 mortality) events during median follow-up of 13 years. Shorter LTL was associated with older age, current smoking, and white race/ethnicity. In whites, each 1 kilobase decrease in LTL was associated with 50% increased hazard of CHD, hazard ratio=1.50 (95% confidence interval, 1.08-2.10), P=0.017. There was no association between CHD and LTL in AfAm. White women with shorter LTL had higher risks of mortality. In contrast, shorter LTL was weakly associated with decreased mortality hazard in AfAm.

CONCLUSIONS

As one of the largest prospective studies of LTL associations with incident CHD and mortality in a racially diverse sample, our study suggests differences in LTL associations with CHD and mortality between white and AfAm postmenopausal women.