Telomere Length Maintenance and Cardio-Metabolic Disease Prevention Through Exercise Training

Mediation role of telomere length in the relationship between physical activity and PhenoAge: A population-based study

Background

The relationship between physical activity (PA), telomere length, and phenotypic age (PhenoAge) represents a pivotal area of investigation in aging research.

Methods

The study encompassed a cohort of 6200 participants aged 20 years and above, sourced from the National Health and Nutrition Examination Survey (NHANES). Physical activity (PA) levels were assessed employing the Global Physical Activity Questionnaire, while DNA samples were collected to determine telomere length, measured in base pairs. PhenoAge, an emerging aging index relying on nine distinct chemical biomarkers, was computed.

Results

Incorporating a fully adjusted model, our analysis showed significant correlations between PA engagement and PhenoAge [Low PA, β (95 % CI): 0.039(-0.071,-0.008), p = 0.021; Moderate PA, β (95 % CI): 0.058(-0.082,-0.034), p < 0.001; High PA, β (95 % CI): 0.069(-0.096,-0.042), p < 0.001]. Furthermore, a positive link emerged between elevated PA levels and telomere length, with a β (95 % CI) of 0.011(0.001, 0.022), p = 0.034. A mediation analysis was performed, demonstrating that telomere length mediated the connection between PA and PhenoAge, with a proportion mediated calculated at 3.57 %.

Conclusions

Our findings suggest that PA may play a key role in mitigating aging processes by preserving telomere length, highlighting the potential of PA as a target for interventions aimed at promoting healthy aging and longevity.

Maternal exercise before and during pregnancy protects against genotoxicity and promotes offspring hippocampal health in mice prenatally exposed to high fructose

The fetal brain is susceptible to programming effects during pregnancy, potentially leading to long-term consequences for offspring's cognitive health. Fructose (FRU) intake is thought to adversely affect fetal brain development, whereas physical exercise before and during pregnancy may be protective. Therefore, this study aimed to assess biochemical and genotoxic changes in maternal hippocampi and behavioral, genotoxic, and biochemical alterations in offspring hippocampi. Seventy female mice were exposed to FRU (20%/L) and/or voluntary physical exercise (VPE) pre-pregnancy for eight weeks, and then mated and exposure was continued until weaning. Offspring were evaluated at 60 days old using behavioral test, genotoxic, and biochemical markers. FRU-induced long-term memory impairment in male offspring, which was alleviated by VPE. VPE mitigated DNA damage from maternal FRU consumption in both maternal and offspring hippocampi in female offspring, VPE increased levels of apurine/apyrimidinic endonuclease 1, erythroid nuclear factor 2, and cAMP response element binding proteins, whereas in males, 8-oxoguanine DNA glycosylase-1 levels upregulate. FRU consumption led to oxidative stress and antioxidant defense alterations in offspring, while VPE mitigated these effects. Telomere shortening was observed in male offspring from mothers who consumed FRU during pregnancy. Our findings suggest that exposure to FRU during (pre)pregnancy and lactation has adverse effects on offspring's hippocampi later in life, and VPE has a protective effect. Overall, the study underscores the significance of maternal dietary and physical habits on long-term offspring health, with an emphasis on implications for adult cognitive function.

Shorter Telomeres and Faster Telomere Attrition in Individuals With Five Syndromic Forms of Intellectual Disability: A Systematic Review and Meta-Analysis

BACKGROUND

People with intellectual disability suffer complex challenges due to adaptive functioning limitations, high rates of chronic diseases and shortened lifespans compared with the general population. Telomere shortening is a hallmark of ageing, and short telomeres are linked to neurological disorders. The main objective of this systematic review and meta-analysis was to identify any differences in telomere length and the rate of telomere attrition in leukocytes and fibroblasts from people with intellectual disability and controls.

METHODS

PubMed, Scopus and ScienceDirect were searched. Articles that compared telomere length in individuals with intellectual disability to apparently healthy age-matched controls were included. Risk of bias was assessed using the AXIS tool and data were analysed using CMA.

RESULTS

Fifteen studies comprised of 17 comparisons provided data and were included in meta-analyses. Compared with healthy controls (N = 481), people with intellectual disability (N = 366) from a known genetic syndrome (Cri du chat, Down, Hoyeraal-Hreidarsson, Williams or Nicolaides-Baraitser) possessed shorter leukocyte telomeres (SMD: -0.853 [95% CI: -1.622 to -0.084], p = 0.03). Similarly, relative to controls (N = 16), people with syndromic intellectual disability (N = 21) possessed shorter fibroblast telomeres (-1.389 [-2.179 to -0.599], p = 0.001). Furthermore, people with syndromic forms of intellectual disability also demonstrated a faster rate (2.09-fold) of telomere shortening.

CONCLUSIONS

Consistent with epidemiological findings on mortality and morbidity risk, people with syndromic intellectual disability appear to undergo a faster rate of biological ageing compared to the general population. These findings emphasise the need for healthy ageing lifestyle (i.e., exercise and stress management) and therapeutic interventions for people with syndromic intellectual disability.

The relationship between physical activity and telomere length in women: A systematic review

Telomere length (TL) is a biomarker of cellular aging with variations observed by sex, age, race, and ethnicity. Prior studies have suggested that physical activity (PA) may positively impact TL by potentially elongating telomeres and slowing cellular aging. However, research examining the optimal type and intensity of PA needed to elicit these changes specific to women remains limited. This systematic review aimed to investigate variations in TL in response to PA among women, exploring how these effects differ by age, race, or ethnicity. Following PRISMA guidelines, searches across five databases identified 17 relevant studies published from 2008 to 2022. A narrative synthesis of study findings indicated PA did not have a significant relationship with TL in women. However, a possible positive relationship was noted between specific types of PA and TL, specific to combined aerobic and strength-training PA and high intensity interval training interventions. The impact of PA on TL appeared to be age-dependent as well, showing significant positive relationships between PA and TL in early and later adulthood but not in middle adulthood. Findings related to race or ethnicity were inconclusive due to limited analyses from the included studies. The studies varied greatly by PA type, intensity, duration, and frequency, which, along with the reliance on self-reported PA measures in the observational studies, impacted the ability to draw firm conclusions. This review underscores the necessity for future research in large cohort studies using objectively measured PA interventions to further clarify the complex associations between PA and TL in women.

A two-sample bidirectional Mendelian randomization analysis between telomere length and hyperthyroidism

Background

hyperthyroidism characterized by low thyrotropin, highlighting complications and risks, including cardiac issues, osteoporosis, adverse pregnancy outcomes, unintentional weight loss, and increased mortality associated with untreated hyperthyroidism. However, the casual association between telomere length (TL) and hyperthyroidism remains unclear.

Objective

We aim to explore the casual relationship between TL and hyperthyroidism.

Methods

A two-sample bidirectional Mendelian randomization (MR) analysis employed the inverse variance weighted (IVW) method, supplemented by additional approaches such as Weighted Median (WM), and MR Egger.

Results

The summary statistics for TL were derived from the UK Biobank, comprising 472,174 individuals, while the data for hyperthyroidism were sourced from the GWAS Catalog and the FinnGen database, encompassing cohorts of 460,499 and 173,938 individuals, respectively. Utilizing 139 genome-wide significant single nucleotide polymorphisms (SNPs) as instrumental variables (IVs) for TL, forward MR analyses indicated a negative causal effect of TL on hyperthyroidism. The risk of hyperthyroidism decreased as genetically predicted TL increased by one standard deviation, as determined by the IVW form GWAS Catalog (OR:0.659,95%CI: 0.541-0.802, p <0.001) and IVW from FinnGen(OR:0.634, 95%CI: 0.479-0.840, p = 0.001). Other MR methods exhibited a consistent trend in the impact of TL on hyperthyroidism. Reverse MR analysis suggested no causal association between TL and hyperthyroidism (p > 0.05). Sensitivity analyses confirmed the robustness of these results, suggesting minimal susceptibility to confounding factors and bias.

Conclusion

The finding that longer telomeres reduce hyperthyroidism risk highlights the need to validate hyperthyroidism's impact on telomere length, offering valuable insights for prevention and treatment.

Effect of Physical Exercise on Telomere Length: Umbrella Review and Meta-Analysis

Background

Telomere length (TL) is a marker of cellular health and aging. Physical exercise has been associated with longer telomeres and, therefore, healthier aging. However, results supporting such effects vary across studies. Our aim was to synthesize existing evidence on the effect of different modalities and durations of physical exercise on TL.

Objective

The aim of this study was to explore the needs and expectations of individuals with physical disabilities and their interventionists for the use of a virtual reality physical activity platform in a community organization.

Methods

We performed an umbrella review and meta-analysis. Data sources included PubMed, Embase, Web of Science, Cochrane Library, and Scopus. We selected systematic reviews and meta-analyses of randomized and nonrandomized controlled clinical trials evaluating the effect of physical exercise on TL.

Results

Our literature search retrieved 12 eligible systematic reviews, 5 of which included meta-analyses. We identified 22 distinct primary studies to estimate the overall effect size of physical exercise on TL. The overall effect size was 0.28 (95% CI 0.118-0.439), with a heterogeneity test value Q of 43.08 (P=.003) and I² coefficient of 51%. The number of weeks of intervention explained part of this heterogeneity (Q_B=8.25; P=.004), with higher effect sizes found in studies with an intervention of less than 30 weeks. Exercise modality explained additional heterogeneity within this subgroup (Q_B=10.28, P=.02). The effect sizes were small for aerobic exercise and endurance training, and moderate for high-intensity interval training.

Conclusions

Our umbrella review and meta-analysis detected a small-moderate positive effect of physical exercise on TL, which seems to be influenced by the duration and type of physical exercise. High quality studies looking into the impact of standardized, evidence-based physical exercise programs on TL are still warranted.

Exercise to combat cancer: focusing on the ends

Cancer remains a leading cause of death worldwide and although prognosis and survivorship after therapy have improved significantly, current cancer treatments have long-term health consequences. For decades telomerase-mediated telomere maintenance has been an attractive anti-cancer therapeutic target due to its abundance and role in telomere maintenance, pathogenesis, and growth in neoplasms. Telomere maintenance-specific cancer therapies, however, are marred by off-target side effects that must be addressed before they reach clinical practice. Regular exercise training is associated with telomerase-mediated telomere maintenance in normal cells, which is associated with healthy aging. A single bout of endurance exercise training dynamically, but temporarily, increases TERT mRNA and telomerase activity, as well as several molecules that control genomic stability and telomere length (i.e., shelterin and TERRA). Considering the epidemiological findings and accumulating research highlighting that exercise significantly reduces the risk of many types of cancers and the anti-carcinogenic effects of exercise on tumor growth in vitro, investigating the governing molecular mechanisms of telomerase control in context with exercise and cancer may provide important new insights to explain these findings. Specifically, the molecular mechanisms controlling telomerase in both healthy cells and tumors after exercise could reveal novel therapeutic targets for tumor-specific telomere maintenance and offer important evidence that may refine current physical activity and exercise guidelines for all stages of cancer care.

Exercise addiction in team sports: A systematic literature review

While regular exercise should be part of the contemporary lifestyle, many people overindulge in it to the point of losing control over their behavior. This condition is known as exercise addiction (EA). Although addiction is an individual phenomenon, and most of the over 1,000 published studies on EA look at individual exercisers, there are studies on team sports athletes, too. Theoretically, these athletes should not manifest exercise addiction, but some studies are projecting the contrary. Therefore, in this literature review, we analyze EA in team athletes. Based on four databases (PsycINFO, SPORTDiscus, Web of Science, and Google Scholar), we located 22 articles conforming to inclusion criteria. These studies suggest a high risk of exercise addiction among team sports participants. While the figures are lower than for individual exercisers, they are in discord with the concept of addiction as a dysfunction, and the lack of a single case of exercise addiction reported (to date) in team sports athletes in the academic literature. In agreement with a recent position paper, we conclude that there are substantial conceptual and measurement errors in exercise addiction research.

Casual effects of telomere length on sarcoidosis: a bidirectional Mendelian randomization analysis

Background

Telomere length, crucial for genomic stability, have been implicated in various inflamm-aging diseases, but their role in sarcoidosis remains unexplored.

Objective

This study aims to explore the casual effects between TL and sarcoidosis via a bidirectional Mendelian Randomization (MR) study.

Methods

We examined single nucleotide polymorphisms (SNPs) associated with TL and sarcoidosis, utilizing available open-access genome-wide association study (GWAS) databases from the UK Biobank and FinnGen. We employed five MR techniques, including Inverse Variance Weighted (IVW), MR Egger, weighted median (WM), Robust adjusted profile score (RAPS), and Maximum likelihood, to assess causal relationships and explore pleiotropy.

Results

Summary data extracted from GWAS datasets of TL (n = 472,174) and (n = 217,758) of European ancestry. Employing 130 SNPs with genome-wide significance as instrumental factors for TL, we detect a significant negative correlation between TL and sarcoidosis (OR: 0.682, 95% confidence interval: 0.524-0.888, p : 0.0045). Similarly, utilizing 6 SNPs with genome-wide significance as instrumental factors for sarcoidosis, we fail to identify a noteworthy association between sarcoidosis and TL (OR: 0.992, 95% confidence interval: 0.979-1.005, p : 0.2424).

Conclusion

Our results suggest that longer telomeres may reduce the risk of sarcoidosis, highlighting TL as a potential biomarker for diagnosis and long-term monitoring. Understanding the critical role of telomere shortening enables more effective focus on diagnosing, treating, and curing sarcoidosis linked to telomeres. Clinical investigations into treatments that enhance TL are warranted.

The association of metabolic syndrome with telomere length as a marker of cellular aging: a systematic review and meta-analysis

Background

It has been suggested that metabolic syndrome (MetS) accelerates the aging process, potentially contributing to the development of age-related complications. Available studies examining the relation of MetS to telomere length (TL), a putative biological marker of aging, have yielded inconclusive findings. This meta-analysis was performed to investigate the association between MetS and TL.

Methods

A comprehensive systematic search was conducted in PubMed and Scopus databases to identify relevant literature published up to February 2024. Standard mean difference (SMD) and standardized beta coefficient (β) with their 95% confidence intervals (CI) were used as effect sizes to measure the associations using the random effects model.

Results

A total of nine studies, comprising a total sample size of 8,606 participants, were eligible for the meta-analysis. No significant difference in mean TL was found between patients with and without MetS (SMD = -0.03, 95%CI = -0.17 to 0.10), with a significant heterogeneity across the studies (I 2 = 89.7.0%, p ≤ 0.001). In contrast, it was revealed that MetS is negatively related to TL (β = -0.08, 95%CI = -0.15 to -0.004). In the subgroup analysis, this finding was supported by the International Diabetes Federation (IDF) definition of MetS.

Conclusion

This meta-analysis highlighted that MetS may be linked to a shorter TL. Additional studies are required to confirm this finding.

The Effects of Exercise on Telomere Length in Persons With Heart Failure

BACKGROUND

Telomere length is reduced in persons with heart failure (HF). Inflammation is a putative mechanism contributing to telomere shortening. Although physical activity is known to increase telomere length, its effects in HF are unknown.

OBJECTIVE

The aim of this study was to examine the effects of exercise on telomere length and its relationship with interleukin (IL)-1β in persons with HF.

METHODS

This secondary analysis of a 3-month home-based aerobic exercise intervention measured total telomere length and IL-1β levels in persons with HF (69% with reduced ejection fraction).

RESULTS

Total telomere length increased and plasma IL-1β levels decreased in the exercise group from baseline to 3 months. Total telomere length was negatively associated with IL-1β at baseline ( r = -0.441 P = .001).

CONCLUSIONS

The association between telomere length and IL-1β suggests a relationship between inflammation and cellular aging. Moderate-intensity exercise may help maintain cellular functions. Further research is needed to examine the effects on outcomes in persons with HF.

A novel metric to improve mismatched primer selection and quantification accuracy in amplifying DNA repeats for quantitative polymerase chain reactions

In quantitative polymerase chain reaction (qPCR) experiments, primers containing mismatches with respect to the template are widely used in measuring repetitive DNA elements. Primer-template mismatches may lead to underestimation of the input sample quantity due to inefficient annealing and amplification. But how primer-template mismatches affect quantification accuracy has not been rigorously investigated. In this study, we performed a series of qPCR experiments in which we tested three pairs of mismatched telomere primers (tel1/tel2, tel1b/tel2b and telg/telc) and two pairs of perfect-match reference gene primers (36B4-F/-R and IFNB1-F/-R) at three different primer concentrations under four cycling conditions. Templates used were genomic DNA from two human cell lines and oligo duplexes which contained telomere sequences, reference gene sequences, or both. We demonstrated that the underestimation of input sample quantity from reactions containing mismatched primers was not due to lower amplification efficiency (E), but due to ineffective usage of the input sample. We defined a novel concept of amplification efficacy (f) which quantifies the effectiveness of input sample amplification by primers. We have modified the conventional qPCR kinetic formula to include f, which corrects the effects of primer mismatches. We demonstrated that reactions containing mismatched telomere primer pairs had similar efficiency (E), but varying degrees of reduced efficacy (f) in comparison to those with the perfect-match gene primer pairs. Using the quantitative parameter f, underestimation of initial target by telomere primers can be adjusted to provide a more accurate measurement. Additionally, we found that the tel1b/tel2b primer set at concentration of 500 nM and 900 nM exhibited the best amplification efficacy f. This study provides a novel way to incorporate an evaluation of amplification efficacy into qPCR analysis. In turn, it improves mismatched primer selection and quantification accuracy in amplifying DNA repeats using qPCR methods.

Intrinsic and environmental basis of aging: A narrative review

Longevity has been a topic of interest since the beginnings of humanity, yet its aetiology and precise mechanisms remain to be elucidated. Aging is currently viewed as a physiological phenomenon characterized by the gradual degeneration of organic physiology and morphology due to the passage of time where both external and internal stimuli intervene. The influence of intrinsic factors, such as progressive telomere shortening, genome instability due to mutation buildup, the direct or indirect actions of age-related genes, and marked changes in epigenetic, metabolic, and mitochondrial patterns constitute a big part of its underlying endogenous mechanisms. On the other hand, several psychosocial and demographic factors, such as diet, physical activity, smoking, and drinking habits, may have an even more significant impact on shaping the aging process. Consequentially, implementing dietary and exercise patterns has been proposed as the most viable alternative strategy for attenuating the most typical degenerative aging changes, thus increasing the likelihood of prolonging lifespan and achieving successful aging.

Telomere Length Associates With Symptom Severity After Mild Traumatic Brain Injury in Older Adults

The objectives were to compare differences in telomere length (TL) among younger (21-54 years) and older adults (≥55) with mild traumatic brain injury (mTBI) to non-injured controls and to examine the association between TL and the severity of post-concussive symptoms over time. We performed a quantitative polymerase chain reaction to determine the TL (Kb/genome) of peripheral blood mononuclear cell samples (day 0, 3 months, and 6 months) from 31 subjects. The Rivermead Post-Concussion Symptoms Questionnaire was used to assess symptoms. Group-by-time comparisons of TL and symptom severity were evaluated with repeated-measures analysis of variance. Multiple linear regression examined the relationship between TL, group (mTBI and non-injured controls), and symptom severity total and subscale scores. Significant aging-related differences in TL were found within mTBI groups by time (day 0, 3 months, and 6 months; p = 0.025). Older adults with mTBI experienced significant worsening of changes in total symptom severity scores over time (day 0, 3 months, and 6 months; p = 0.016). Shorter TLs were associated with higher total symptom burden among each of the four groups at day 0 (baseline; p = 0.035) and 3 months (p = 0.038). Shorter TL was also associated with higher cognitive symptom burden among the four groups at day 0 (p = 0.008) and 3 months (p = 0.008). Shorter TL was associated with higher post-injury symptom burden to 3 months in both older and younger persons with mTBI. Large-scale, longitudinal studies of factors associated with TL may be useful to delineate the mechanistic underpinnings of higher symptom burden in adults with mTBI.

Physical Activity on Telomere Length as a Biomarker for Aging: A Systematic Review

Background

Overall life expectancy continues to rise, approaching 80 years of age in several developed countries. However, healthy life expectancy lags far behind, which has, in turn, contributed to increasing costs in healthcare. One way to improve health and attenuate the socio-economic impact of an aging population is to increase overall fitness through physical activity. Telomere attrition or shortening is a well-known molecular marker in aging. As such, several studies have focused on whether exercise influences health and aging through telomere biology. This systematic review examines the recent literature on the effect of physical activity on telomere length (TL) and/or telomerase activity as molecular markers of aging.

Methods

A focused search was performed in the databases PubMed and Web of Science for retrieving relevant articles over the past ten years. The search contained the following keywords: exercise, sport, physical activity, fitness, sedentary, physical inactivity, telomere, telomere length, t/s ratio, and telomerase. PRISMA guidelines for systematic reviews were observed.

Results

A total of 43 articles were identified and categorized into randomized controlled trials (RCT), observational or interventional studies. RCTs (n = 8) showed inconsistent findings of increased TL length with physical activity in, e.g. obese, post-menopausal women. In comparison with a predominantly sedentary lifestyle, observational studies (n = 27) showed significantly longer TL with exercise of moderate to vigorous intensity; however, there was no consensus on the duration and type of physical activity and training modality. Interventional studies (n = 8) also showed similar findings of significantly longer TL prior to exercise intervention; however, these studies had smaller numbers of enrolled participants (mostly of high-performance athletes), and the physical activities covered a range of exercise intensities and duration. Amongst the selected studies, aerobic training of moderate to vigorous intensity is most prevalent. For telomere biology analysis, TL was determined mainly from leukocytes using qPCR. In some cases, especially in RCT and interventional studies, different sample types such as saliva, sperm, and muscle biopsies were analyzed; different leukocyte cell types and potential genetic markers in regulating telomere biology were also investigated.

Conclusions

Taken together, physical activity with regular aerobic training of moderate to vigorous intensity appears to help preserve TL. However, the optimal intensity, duration of physical activity, as well as type of exercise still need to be further elucidated. Along with TL or telomerase activity, participants’ fitness level, the type of physical activity, and training modality should be assessed at different time points in future studies, with the plan for long-term follow-up. Reducing the amount of sedentary behavior may have a positive effect of preserving and increasing TL. Further molecular characterization of telomere biology in different cell types and tissues is required in order to draw definitive causal conclusions on how physical activity affects TL and aging.

Exercise regulates shelterin genes and microRNAs implicated in ageing in Thoroughbred horses

Ageing causes a gradual deterioration of bodily functions and telomere degradation. Excessive telomere shortening leads to cellular senescence and decreases tissue vitality. Six proteins, called shelterin, protect telomere integrity and control telomere length through telomerase-dependent mechanisms. Exercise training appears to maintain telomeres in certain somatic cells, although the underlying molecular mechanisms are incompletely understood. Here, we examined the influence of a single bout of vigorous exercise training on leukocyte telomerase reverse transcriptase (TERT) and shelterin gene expression, and the abundance of three microRNAs (miRNAs) implicated in biological ageing (miRNA-143, -223 and -486-5p) in an elite athlete and large animal model, Thoroughbred horses. Gene and miRNA expression were analysed using primer-based and TaqMan Assay qPCR. Leukocyte TRF1, TRF2 and POT1 expression were all significantly increased whilst miR-223 and miR-486-5p were decreased immediately after vigorous exercise (all p < 0.05), and tended to return to baseline levels 24 h after training. Relative to the young horses (~ 3.9 years old), middle-aged horses (~ 14.8 years old) exhibited reduced leukocyte TERT gene expression, and increased POT1 and miR-223 abundance (all p < 0.05). These data demonstrate that genes transcribing key components of the shelterin-telomere complex are influenced by ageing and dynamically regulated by a single bout of vigorous exercise in a large, athletic mammal - Thoroughbred horses. Our findings also implicate TERT and shelterin gene transcripts as potential targets of miR-223 and miR-486-5p, which are modulated by exercise and may have a role in the telomere maintenance and genomic stability associated with long-term aerobic training.

Aerobic exercise and telomere length in patients with systolic heart failure: protocol study for a randomized controlled trial

Background

Heart failure (HF) with reduced ejection fraction (HFrEF) is a syndrome that leads to fatigue and reduced functional capacity due to disease-related pathophysiological mechanisms. Aerobic exercise (AERO) plays a key role in improving HF outcomes, such as an increase in peak oxygen uptake (VO₂peak). In addition, HF promotes cell senescence, which involves reducing telomere length. Several studies have shown that patients with a worse prognosis (i.e., reduced VO₂ peak) also have shorter telomeres. However, the effects of AERO on telomere length in patients with HFrEF are still unknown. In an attempt to fill this gap, we designed a study to determine the effects of 16 weeks of aerobic training (32 sessions) on telomere length in HFrEF patients.

Methods

In this single-center randomized controlled trial, men and women between 50 and 80 years old will be allocated into two different groups: a moderate-intensity aerobic training and a control grouTelomere length, functional capacity, echocardiographic variables, endothelial function, and walking ability will be assessed before and after the 16-week intervention period.

Discussion

Understanding the role of physical exercise in biological aging in HFrEF patients is relevant. Due to cell senescence, these individuals have shown a shorter telomere length. AERO can delay biological aging according to a balance in oxidative stress through antioxidant action. Positive telomere length results are expected for the aerobic training group.

Trial registration

ClinicalTrials.gov NCT03856736. Registered on February 27, 2019

Telomere length in peripheral leukocytes is a sensitive marker for assessing genetic damage among workers exposed to isopropanol, lead and noise: the case of an electronics manufacturer

BACKGROUND

Workers in electronics manufacturers may be exposed to various occupational hazards such as isopropanol, lead, and noise. Telomeres are special segments of cap-like DNA protein complex at end of liner chromosomes in eukaryotic cells. Telomere length is a potential marker of genetic damage. The aim of this study is to evaluate the effect of occupational hazards on the relative telomere length (rTL) of peripheral blood cells of workers in an electronics manufacturer, and to explore whether relative telomere length could be a biomarker for assessing genetic damage in the electronics manufacturing industry.

METHODS

We investigated a large-scale electronics manufacturer in the Pearl River Delta Region. We ultimately collected 699 qualified workers (248 with isopropanol exposure, 182 with lead exposure, 157 with noise exposure, and 112 controls). During physical examination of the workers, we gave them questionnaires to understand their health statuses and living habits. We also collected peripheral blood samples from these workers to test exposure levels and rTL in the leucocytes.

RESULTS

The concentrations of air isopropanol in all monitored workshops was 25.3 mg/m³ and air lead smoke was 0.020 mg/m³. The maximum equivalent continuous A sound level noise exposure position was 82.2dB (A). All were lower than those in the Occupational Exposure Limits in Workplaces in China. Urinary acetone in the isopropanol exposed group was 1.04 (0, 1.50) mg/L, and cumulative urinary acetone was 1.48 (0, 5.09) mg-years/L. Blood lead levels (BLLs) were 28.57 (22.77, 37.06) µg/dL, and cumulative blood lead levels (CBLLs) were 92.75 (55.47, 165.13) µg-years/dL. rTL was different between occupational exposed workers and controls: rTL was 0.140 units (95 % CI: 0.022, 0.259) shorter in lead exposed workers and 0.467 units (95 % CI: 0.276-0.658) shorter in noise exposed workers compared to the controls. There is no statistical difference in rTL between isopropanol exposure workers and the controls. In order to elucidate the relationship between rTL and occupational hazards exposure, we divided the isopropanol exposure workers into three groups (0, ~1.43 mg/L, and >1.43 mg/L). None of the rTL difference was statistically significant among exposed workers at different uroacetone levels (P>0.05). The groups with ≥100 µg/dL blood lead had shorter rTL than the group with blood lead below 100 µg/dL (F=4.422, P=0.013). We incorporated age, gender, birthplace, race, education level, smoking, and alcohol consumption into the linear regression equation. Only blood lead concentration (X) was entered into the regression equation, yielding a multivariate linear regression equation of Y=0.397-0.124X (F=8.091, P=0.005). Workers with different hearing loss also had statistically significant differences in rTL (F=5.731, P=0.004). rTL was a protective factor for the occurrence of noise-induced hearing loss (NIHL). The longer the rTL, the lower the risk of NIHL [OR=0.64 (0.42, 0.98)].

CONCLUSIONS

rTL was shorter in lead exposed workers and noise exposed workers, and it was a protective factor for the occurrence of the noise-induced hearing loss. Thus, rTL of peripheral blood may be a sensitive marker of genetic damage among workers in environments with lead and noise exposure.

Metabolic Signature of Leukocyte Telomere Length in Elite Male Soccer Players

Introduction: Biological aging is associated with changes in the metabolic pathways. Leukocyte telomere length (LTL) is a predictive marker of biological aging; however, the underlying metabolic pathways remain largely unknown. The aim of this study was to investigate the metabolic alterations and identify the metabolic predictors of LTL in elite male soccer players. Methods: Levels of 837 blood metabolites and LTL were measured in 126 young elite male soccer players who tested negative for doping abuse at anti-doping laboratory in Italy. Multivariate analysis using orthogonal partial least squares (OPLS), univariate linear models and enrichment analyses were conducted to identify metabolites and metabolic pathways associated with LTL. Generalized linear model followed by receiver operating characteristic (ROC) analysis were conducted to identify top metabolites predictive of LTL. Results: Sixty-seven metabolites and seven metabolic pathways showed significant associations with LTL. Among enriched pathways, lysophospholipids, benzoate metabolites, and glycine/serine/threonine metabolites were elevated with longer LTL. Conversely, monoacylglycerols, sphingolipid metabolites, long chain fatty acids and polyunsaturated fatty acids were enriched with shorter telomeres. ROC analysis revealed eight metabolites that best predict LTL, including glutamine, N-acetylglutamine, xanthine, beta-sitosterol, N2-acetyllysine, stearoyl-arachidonoyl-glycerol (18:0/20:4), N-acetylserine and 3-7-dimethylurate with AUC of 0.75 (0.64-0.87, p < 0.0001). Conclusion: This study characterized the metabolic activity in relation to telomere length in elite soccer players. Investigating the functional relevance of these associations could provide a better understanding of exercise physiology and pathophysiology of elite athletes.

Intra-uterine effects on adult muscle strength

BACKGROUND

Maternal behaviors and exposures affect fetal growth and development. Smoking, malnutrition, sedentary behavior, and stress can each lead to fetal programming and intra-uterine growth restriction. As a result, tissue development may be impaired. Problems with muscle formation can lead to reductions in muscle performance throughout life. The purpose of this study was to determine if in utero effects on muscle mass, muscle function, or both are responsible for the relationship between size at birth and adult muscle strength.

STUDY DESIGN

One hundred adults (ages 18-40), who were singletons born at term (37-42 weeks), participated. Birth weight was adjusted for gestational age using neonatal growth reference data. Maximal voluntary contractions (MVC) of dominant and non-dominant handgrip, and right and left leg extension were measured. Linear regression analysis was used to determine the association between adjusted birth weight and muscle strength. Sex and lean body mass were covariates.

RESULTS

Dominant handgrip MVC increased by 1.533 kg per 1 SD increase in adjusted birth weight (p = 0.004). Lean body mass had a significant indirect effect on this relationship. The relationship between handgrip strength and adjusted birth weight was strongest among female subjects. No other muscle strength measures were significantly associated with adjusted birth weight.

CONCLUSIONS

Birth size was a significant predictor of handgrip strength in adulthood. Including lean body mass attenuated, but did not remove, the association. Thus, among individuals born to term, having a smaller-than-predicted birth size likely causes both reductions in muscle mass formation and decreased muscle function, ultimately impacting muscle strength in adulthood.

Short-Term Aerobic Exercise Did Not Change Telomere Length While It Reduced Testosterone Levels and Obesity Indexes in PCOS: A Randomized Controlled Clinical Trial Study

Metabolic and hormonal outcomes of polycystic ovary syndrome (PCOS) have implications on telomere biology and physical activity may prevent telomere erosion. We sought to observe the effects of continuous (CAT) and intermittent (IAT) aerobic training on telomere length, inflammatory biomarkers, and its correlation with metabolic, hormonal, and anthropometric parameters of PCOS. This randomized controlled clinical trial study included 87 PCOS randomly stratified according to body mass index (BMI) in CAT (n = 28), IAT (n = 29) and non-training control group (CG, n = 30). The exercises were carried out on a treadmill, three times per week for 16 weeks. The participants' anthropometric characteristics and biochemical and hormonal concentrations were measured before and after aerobic training or observation period, as the telomere length that was evaluated using quantitative real-time PCR. Four months of aerobic exercises (CAT or IAT) did not alter telomere length and inflammatory biomarkers in PCOS women. Obesity index as BMI and waist circumference (WC), and inflammatory biomarkers negatively affect telomeres. The hyper-andro-genism measured by testosterone levels was reduced after both exercises (CAT, p ≤ 0.001; IAT, p = 0.019). In particular, the CAT reduced WC (p = 0.045), hip circumference (p = 0.032), serum cholesterol (p ≤ 0.001), and low-density lipoprotein (p = 0.030). Whereas, the IAT decreased WC (p = 0.014), waist-to-hip ratio (p = 0.012), free androgen index (FAI) (p = 0.037). WC (p = 0.049) and body fat (p = 0.015) increased in the non-training group while total cholesterol was reduced (p = 0.010). Booth exercises reduced obesity indices and hyperandrogenism on PCOS women without changes in telomere length or inflammatory biomarkers.

Shorter telomeres among individuals with physical disability: The moderating role of perceived stress

OBJECTIVES

Evidence suggests that individuals with physical disability may suffer from psychological distress and accelerated cellular aging, manifested by shortened telomere length (TL), compared with healthy individuals. Studies indicate that high levels of perceived stress and depression may increase the physiological susceptibility and thus, may contribute to a short TL. However, the moderating role of perceived stress and depression within the relationship between physical disability and TL remains unknown.

METHODS

The participants consisted of 119 male subjects (mean age 54.36 years, range 35-70). Of them, 30 were able-bodied and 86 had a physical disability: 34 were due to Poliomyelitis (polio) and 55 were due to spinal cord injury (SCI). Blood samples for TL analysis were collected; the participants completed questionnaires and underwent disability evaluation.

RESULTS

Participants with disability had a shorter TL as well as elevated levels of perceived stress and depression compared with able-bodied controls. Both the perceived stress and depression were correlated with a shorter TL. Nonetheless, perceived stress, rather than depression, moderated the relationship between disability and TL; among participants with higher perceived stress levels, in particular, individuals with physical disability had a shorter TL than the able-bodied controls.

DISCUSSION

The present findings suggest that individuals with physical disability and who exhibit high levels of perceived stress may be particularly vulnerable for accelerated cellular aging, suggesting that perceived stress can be used as a valuable target for intervention.

Exercise training increases telomerase reverse transcriptase gene expression and telomerase activity: A systematic review and meta-analysis

Telomeres protect genomic stability and shortening is one of the hallmarks of ageing. Telomerase reverse transcriptase (TERT) is the major protein component of telomerase, which elongates telomeres. Given that short telomeres are linked to a host of chronic diseases and the therapeutic potential of telomerase-based therapies as treatments and a strategy to extend lifespan, lifestyle factors that increase TERT gene expression and telomerase activity could attenuate telomere attrition and contribute to healthy biological ageing. Physical activity and maximal aerobic fitness are associated with telomere maintenance, yet the molecular mechanisms remain unclear. Therefore, the purpose of this systematic review and meta-analysis was to identify the influence of a single bout of exercise and long-term exercise training on TERT expression and telomerase activity. A search of human and rodent trials using the PubMed, Scopus, Science Direct and Embase databases was performed. Based on findings from the identified and eligible trials, both a single bout of exercise (n; standardised mean difference [95%CI]: 5; SMD: 1.19 [0.41-1.97], p = 0.003) and long-term exercise training (10; 0.31 [0.03-0.60], p = 0.03) up-regulates TERT and telomerase activity in non-cancerous somatic cells. As human and rodent studies were included in the meta-analyses both exhibited heterogeneity (I² = 55-87%, p < 0.05). Endurance athletes also exhibited increased leukocyte TERT and telomerase activity compared to their inactive counterparts. These findings suggest exercise training as an inexpensive lifestyle factor that increases TERT expression and telomerase activity. Regular exercise training could attenuate telomere attrition through a telomerase-dependent mechanism and ultimately extend health-span and longevity.

Regular, Intense Exercise Training as a Healthy Aging Lifestyle Strategy: Preventing DNA Damage, Telomere Shortening and Adverse DNA Methylation Changes Over a Lifetime

Exercise training is one of the few therapeutic interventions that improves health span by delaying the onset of age-related diseases and preventing early death. The length of telomeres, the 5'-TTAGGG n -3' tandem repeats at the ends of mammalian chromosomes, is one of the main indicators of biological age. Telomeres undergo shortening with each cellular division. This subsequently leads to alterations in the expression of several genes that encode vital proteins with critical functions in many tissues throughout the body, and ultimately impacts cardiovascular, immune and muscle physiology. The sub-telomeric DNA is comprised of heavily methylated, heterochromatin. Methylation and histone acetylation are two of the most well-studied examples of the epigenetic modifications that occur on histone proteins. DNA methylation is the type of epigenetic modification that alters gene expression without modifying gene sequence. Although diet, genetic predisposition and a healthy lifestyle seem to alter DNA methylation and telomere length (TL), recent evidence suggests that training status or physical fitness are some of the major factors that control DNA structural modifications. In fact, TL is positively associated with cardiorespiratory fitness, physical activity level (sedentary, active, moderately trained, or elite) and training intensity, but is shorter in over-trained athletes. Similarly, somatic cells are vulnerable to exercise-induced epigenetic modification, including DNA methylation. Exercise-training load, however, depends on intensity and volume (duration and frequency). Training load-dependent responses in genomic profiles could underpin the discordant physiological and physical responses to exercise. In the current review, we will discuss the role of various forms of exercise training in the regulation of DNA damage, TL and DNA methylation status in humans, to provide an update on the influence exercise training has on biological aging.

Co-expression analysis identifies networks of miRNAs implicated in biological ageing and modulated by short-term interval training

Exercise training seems to promote healthy biological ageing partly by inducing telomere maintenance, yet the molecular mechanisms are not fully understood. Recent studies have emphasised the importance of microRNAs (miRNAs) in ageing and their ability to mirror pathophysiological alterations associated with age-related diseases. We examined the association between aerobic fitness and leukocyte telomere length before determining the influence of vigorous exercise training on the regulation of leukocyte miRNA networks. Telomere length was positively correlated to aerobic fitness (r = 0.32, p = 0.02). 104 miRNAs were differentially expressed after six weeks of thrice-weekly sprint interval training (SIT) in healthy men (q < 0.05). Gene co-expression analysis (WGCNA) detected biologically meaningful miRNA networks, five of which were significantly correlated with pre-SIT and post-SIT expression profiles (p < 0.001) and telomere length. Enrichment analysis revealed that the immune response, T cell differentiation and lipid metabolism associated miRNAs clusters were significantly down-regulated after SIT. Using data acquired from the Gene Expression Omnibus (GEO), we also identified two co-expressed miRNAs families that were modulated by exercise training in previous investigations. Collectively, our findings highlight the miRNA networks implicated in exercise adaptations and telomere regulation, and suggest that SIT may attenuate biological ageing through the control of the let-7 and miR-320 miRNA families.

Influence of Body Fat on Oxidative Stress and Telomere Length of Master Athletes

ABSTRACT

Aguiar, SS, Rosa, TS, Sousa, CV, Santos, PA, Barbosa, LP, Deus, LA, Rosa, EC, Andrade, RV, and Simões, HG. Influence of body fat on oxidative stress and telomere length of master athletes. J Strength Cond Res 35(6): 1693-1699, 2021-The present investigation analyzed the role of body fat and training history on biological aging of master athletes by comparing and verifying the relationships between markers of adiposity, oxidative balance, and telomere length (TL) in middle-aged runners and untrained individuals. Master athletes (sprinters and endurance runners, n = 21; 51.62 ± 8.19 years) and untrained age-matched controls (n = 11; 45.41 ± 10.34 years) had blood samples collected for biochemical and biomolecular analyzes. Pro-oxidant and antioxidant measures as well as DNA extraction were performed using commercial kits. Relative TL (T/S) was determined in leukocytes through quantitative polymerase chain reaction analyses. Master athletes had lower body fat and longer TL than untrained controls (body fat: 12.21 ± 4.14% vs. 26.03 ± 4.29%; TL: 1.10 ± 0.84 vs. 0.56 ± 0.56 T/S; p < 0.05). Furthermore, master athletes also showed a better oxidative balance than untrained controls (p < 0.05). A negative correlation was observed between TL and body fat (r = -0.471; p = 0.007), and conicity index (r = -0.407; p = 0.021), catalase activity (r = -0.569; p = 0.001), and CAT/TBARS ratio (r = -0.463; p = 0.008) for the whole sample. In conclusion, master athletes have longer TL, better oxidative profile, and lower body fat than untrained individuals. Moreover, for this middle-aged sample, body fat was inversely correlated with both TL and markers of oxidative balance, demonstrating the key role of adiposity in biological aging.

Identification of Novel Biomarkers for Pre-diabetic Diagnosis Using a Combinational Approach

Reliable protein markers for pre-diabetes in humans are not clinically available. In order to identify novel and reliable protein markers for pre-diabetes in humans, healthy volunteers and patients diagnosed with pre-diabetes and stroke were recruited for blood collection. Blood samples were collected from healthy and pre-diabetic subjects 12 h after fasting. BMI was calculated from body weight and height. Fasting blood glucose (FBG), glycated hemoglobin (HbA1C), triglyceride (TG), total cholesterol, high-density lipoprotein, low-density lipoprotein (LDL), insulin and albumin were assayed by automated clinical laboratory methods. We used a quantitative proteomics approach to identify 1074 proteins from the sera of pre-diabetic and healthy subjects. Among them, 500 proteins were then selected using Mascot analysis scores. Further, 70 out of 500 proteins were selected via volcano plot analysis according to their statistical significance and average relative protein ratio. Eventually, 7 serum proteins were singled out as candidate markers for pre-diabetes due to their diabetic relevance and statistical significance. Immunoblotting data demonstrated that laminin subunit alpha 2 (LAMA2), mixed-lineage leukemia 4 (MLL4), and plexin domain containing 2 (PLXDC2) were expressed in pre-diabetic patients but not healthy volunteers. Receiver operating characteristic curve analysis indicated that the combination of the three proteins has greater diagnostic efficacy than any individual protein. Thus, LAMA2, MLL4 and PLXDC2 are novel and reliable serum protein markers for pre-diabetic diagnosis in humans.

Mediterranean-Type Dietary Pattern and Physical Activity: The Winning Combination to Counteract the Rising Burden of Non-Communicable Diseases (NCDs)

Non-communicable diseases (NCDs) (mainly cardiovascular diseases, cancers, chronic respiratory diseases and type 2 diabetes) are the main causes of death worldwide. Their burden is expected to rise in the future, especially in less developed economies and among the poor spread across middle- and high-income countries. Indeed, the treatment and prevention of these pathologies constitute a crucial challenge for public health. The major non-communicable diseases share four modifiable behavioral risk factors: unhealthy diet, physical inactivity, tobacco usage and excess of alcohol consumption. Therefore, the adoption of healthy lifestyles, which include not excessive alcohol intake, no smoking, a healthy diet and regular physical activity, represents a crucial and economical strategy to counteract the global NCDs burden. This review summarizes the latest evidence demonstrating that Mediterranean-type dietary pattern and physical activity are, alone and in combination, key interventions to both prevent and control the rise of NCDs.

Can Positive Affective Variables Mediate Intervention Effects on Physical Activity? A Systematic Review and Meta-Analysis

Well-developed theories are necessary to guide the public in increasing physical activity (PA) and promoting physical health. The role of positive affective variables (PAVs) in exercise is gaining more attention, but none of the literature has provided a systematic review and quantitative analysis of its mediating role. Therefore, the purposes of this study are (1) to systematically review studies of PA interventions, that use PAVs as the mediating variables, in order to evaluate and provide narrative summaries of these studies; (2) to statistically synthesize evidence for the mechanism of the effects of PAVs on PA outcomes. To conduct an extensive search, a PRISMA-compliant protocol was completed, and five electronic databases had been searched by 1 April 2020. We used a two-stage structural equation modeling (TSSEM) analysis approach to test how interventions trigger the critical PA change process to influence outcomes. The search strategy generated 1,732 papers potentially relevant to this study; forty of these studies met the data extraction criteria for meta-analytic mediation analysis. The path coefficient from intervention to PAV a = 0.26 (95% CI = 0.08 to 0.44), the path coefficient from PAV to PA b = 0.21 (95% CI = 0.13 to 0.28), and the direct effect from intervention to PA is also significant (c = 0.19, 95% CI = 0.12 to 0.26). In addition, the indirect effect of intervention on PA via PAV was statistically significant (c' = 0.05, 95% CI = 0.02 to 0.10). This reveals that PAVs partially mediate the relationship between interventions and PA. Our study is the first to systematically summarize the effects of experimental studies to increase PA through PAVs. It is highly recommended to make future interventions more innovative and to target the PAVs as mediators with higher fidelity.

The effect of 12-week resistance exercise training on serum levels of cellular aging process parameters in elderly men

BACKGROUND

Regular physical activity has a positive effect on the prevention of cellular aging. The present study investigated the effect of 12-week resistance training (RT) on serum levels of Sirtuin-1 (SIRT1), Sirtuin-3 (SIRT3), Sirtuin-6 (SIRT6), Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1-α), and telomerase enzyme in elderly men.

METHODS

For this purpose, 30 elderly men (age 66.23 ± 0.57 years) were randomly divided into two groups: resistance training group (RET, n = 15) and control group (CTR, n = 15). Participants in RET performed RT protocols with intensity of 60% one-repetition maximum (3×/week, 4 sets of the six exercise circuits). Body composition, physical functioning and, blood samples were assessed before (pre-test) and after (post-test) a 12-week intervention.

RESULTS

The results showed that there was a significant increase in serum levels of SIRT1 (P = 0.001), SIRT3 (P = 0.001), SIRT6 (P = 0.02), PGC1-α (P = 0.001), and telomerase enzyme (P = 0.001) in RET. Also, we found a significant difference between the RET and CTR in serum levels of SIRT1 (P = 0.001), SIRT3 (P = 0.001), SIRT6 (P = 0.037), PGC1-α (P = 0.007), and telomerase enzyme (P = 0.001).

CONCLUSIONS

12-Week RT increased the levels of proteins associated with the biological aging process in elderly men. It seems that the RT may have beneficial effects on cellular senescence and also improved impaired mitochondrial protein and enzymatic functional induced aging.

Telomere length correlates with subtelomeric DNA methylation in long-term mindfulness practitioners

Mindfulness and meditation techniques have proven successful for the reduction of stress and improvement in general health. In addition, meditation is linked to longevity and longer telomere length, a proposed biomarker of human aging. Interestingly, DNA methylation changes have been described at specific subtelomeric regions in long-term meditators compared to controls. However, the molecular basis underlying these beneficial effects of meditation on human health still remains unclear. Here we show that DNA methylation levels, measured by the Infinium HumanMethylation450 BeadChip (Illumina) array, at specific subtelomeric regions containing GPR31 and SERPINB9 genes were associated with telomere length in long-term meditators with a strong statistical trend when correcting for multiple testing. Notably, age showed no association with telomere length in the group of long-term meditators. These results may suggest that long-term meditation could be related to epigenetic mechanisms, in particular gene-specific DNA methylation changes at distinct subtelomeric regions.

The effects of short-term combined exercise training on telomere length in obese women: a prospective, interventional study

Background

Telomere length is inversely associated with the senescence and aging process. Parallelly, obesity can promote telomere shortening. Evidence suggests that physical activity may promote telomere elongation.

Objective

This study’s objective is to evaluate the effects of combined exercise training on telomere length in obese women.

Design and Methods

Twenty pre-menopausal women (BMI 30–40 kg/m², 20–40 years) submitted to combined training (strength and aerobic exercises), but only 13 finished the protocol. Each exercise session lasted 55 min/day, three times a week, throughout 8 weeks. Anthropometric data, body composition, physical performance (Vo_2max), and 8-h fasting blood samples were taken before and after 8 weeks of training. Leukocyte DNA was extracted for telomere length by RT-qPCR reaction, using the 2^−ΔΔCt methodology.

Results

After the training intervention, significant differences (p < 0.05) were observed in telomere length (respectively before and after, 1.03 ± 0.04 to 1.07 ± 0.04 T/S ratio), fat-free mass (46 ± 7 to 48 ± 5 kg), Vo_2max (35 ± 3 to 38 ± 3 ml/kg/min), and waist circumference (96 ± 8 to 90 ± 6 cm). In addition, an inverse correlation between waist circumference and telomere length was found, before (r = − 0.536, p = 0.017) and after (r = − 0.655, p = 0.015) exercise training.

Conclusion

Combined exercise promoted leukocyte telomere elongation in obese women. Besides, the data suggested that greater waist circumference may predict shorter telomere length.

Clinical Trial Registration

ClinicalTrails.gov, NCT03119350. Retrospectively registered on 18 April 2017

Aerobic capacity and telomere length in human skeletal muscle and leukocytes across the lifespan

A reduction in aerobic capacity and the shortening of telomeres are hallmarks of the ageing process. We examined whether a lower aerobic capacity is associated with shorter TL in skeletal muscle and/or leukocytes, across a wide age range of individuals. We also tested whether TL in human skeletal muscle (MTL) correlates with TL in leukocytes (LTL). Eighty-two recreationally active, healthy men from the Gene SMART cohort (31.4±8.2 years; body mass index (BMI)=25.3±3.3kg/m²), and 11 community dwelling older men (74.2±7.5years-old; BMI=28.7±2.8kg/m²) participated in the study. Leukocytes and skeletal muscle samples were collected at rest. Relative telomere length (T/S ratio) was measured by RT-PCR. Associations between TL, aerobic capacity (VO₂ peak and peak power) and age were assessed with robust linear models. Older age was associated with shorter LTL (45% variance explained, P<0.001), but not MTL (P= 0.7). Aerobic capacity was not associated with MTL (P=0.5), nor LTL (P=0.3). MTL and LTL were correlated across the lifespan (r_s=0.26, P=0.03). In healthy individuals, age explain most of the variability of LTL and this appears to be independent of individual aerobic capacity. Individuals with longer LTL also have a longer MTL, suggesting that there might be a shared molecular mechanism regulating telomere length.

The association between sperm telomere length, cardiorespiratory fitness and exercise training in humans

Telomeres protect genomic integrity and shorten in somatic cells due to the end replication problem. Sperm telomeres are, however, longer in older individuals and linked to semen quality. Exercise training may attenuate age-related telomere shortening in somatic cells, but the influence of exercise on sperm telomeres is unknown. Mature sperm from 34 healthy men were isolated by density gradient centrifugation and telomere length was assessed by qPCR. No significant correlations were observed between telomere length, fitness or exercise performance. Inter-individual variation in sperm telomere length responses to a 6-wk vigorous exercise training intervention (ΔT/S ratio range: −0.49 to 0.87) and a strong correlation between improvements in fitness and sperm telomere lengthening were revealed (r = 0.87, p < 0.001). These preliminary data suggest exercise training may regulate sperm telomere length and should encourage larger studies to explore the implications this may have on the health of the next generation.

Telomere regulation: lessons learnt from mice and men, potential opportunities in horses

Telomeres are genetically conserved nucleoprotein complexes located at the ends of chromosomes that preserve genomic stability. In large mammals, somatic cell telomeres shorten with age, owing to the end replication problem and lack of telomere-lengthening events (e.g. telomerase and ALT activity). Therefore, telomere length reflects cellular replicative reserve and mitotic potential. Environmental insults can accelerate telomere attrition in response to cell division and DNA damage. As such, telomere shortening is considered one of the major hallmarks of ageing. Much effort has been dedicated to understanding the environmental perturbations that accelerate telomere attrition and therapeutic strategies to preserve or extend telomeres. As telomere dynamics seem to reflect cumulative cellular stress, telomere length could serve as a biomarker of animal welfare. The assessment of telomere dynamics (i.e. rate of shortening) in conjunction with telomere-regulating genes and telomerase activity in racehorses could monitor long-term animal health, yet it could also provide some unique opportunities to address particular limitations with the use of other animal models in telomere research. Considering the ongoing efforts to optimise the health and welfare of equine athletes, the purpose of this review is to discuss the potential utility of assessing telomere length in Thoroughbred racehorses. A brief review of telomere biology in large and small mammals will be provided, followed by discussion on the biological implications of telomere length and environmental (e.g. lifestyle) factors that accelerate or attenuate telomere attrition. Finally, the utility of quantifying telomere dynamics in horses will be offered with directions for future research.

Controlling for baseline telomere length biases estimates of the rate of telomere attrition

Longitudinal studies have sought to establish whether environmental exposures such as smoking accelerate the attrition of individuals' telomeres over time. These studies typically control for baseline telomere length (TL) by including it as a covariate in statistical models. However, baseline TL also differs between smokers and non-smokers, and telomere attrition is spuriously linked to baseline TL via measurement error and regression to the mean. Using simulated datasets, we show that controlling for baseline TL overestimates the true effect of smoking on telomere attrition. This bias increases with increasing telomere measurement error and increasing difference in baseline TL between smokers and non-smokers. Using a meta-analysis of longitudinal datasets, we show that as predicted, the estimated difference in telomere attrition between smokers and non-smokers is greater when statistical models control for baseline TL than when they do not, and the size of the discrepancy is positively correlated with measurement error. The bias we describe is not specific to smoking and also applies to other exposures. We conclude that to avoid invalid inference, models of telomere attrition should not control for baseline TL by including it as a covariate. Many claims of accelerated telomere attrition in individuals exposed to adversity need to be re-assessed.

Age-associated telomere shortening in Thoroughbred horses

Telomeres are genetically conserved repetitive terminal DNA that protect against genomic instability and shorten with ageing. Here, we reveal the leukocyte telomere length of Equus caballus by measuring terminal restriction fragments (TRFs) using Southern Blot analysis in a cohort of 43 Thoroughbred horses (age: 24 h-25 years). Heterogeneous TRFs were observed in each animal and large inter-animal variation in mean TRF was observed (range: 10.5-18.7 kbp). Mean TRFs were inversely correlated with age (r = -0.47). The estimated yearly rate of telomere attrition was 134 bp. Horses should be considered as an alternative animal model to investigate environmental and lifestyle factors that regulate telomeres and promote healthy ageing.

Leucocyte Telomere Length and Glucose Tolerance Status in Mixed-Ancestry South Africans

Telomeres are DNA-tandem repeats situated at the ends of chromosomes and are responsible for genome stabilization. They are eroded by increased cell division, age and oxidative stress with shortened leucocyte telomeres (LTL) being associated with inflammatory disorders, including Type II diabetes. We assessed LTL in 205 participants across glucose tolerance groups at baseline and after three years in the mixed ancestry population of South Africa which have been shown to have high rates of obesity and T2DM. Baseline and follow-up data included glucose tolerance status, anthropometric measurements, lipids, insulin, γ-glutamyl transferase (GGT), cotinine, and HbA1c. Telomere length was measured using the absolute telomere q-PCR method performed on a Bio-Rad MiniOpticon Detector. No significant difference was detected in LTL across glucose tolerance groups at both time points, including in subjects who showed a deterioration of their glucose tolerance status. There was, however, a significant negative correlation between LTL and age which was more pronounced in diabetes (r = −0.18, p = 0.04) and with GGT (r = −0.16, p = 0.027). This longitudinal study has demonstrated that LTL shortening is not evident within three years, nor is it associated with glycaemia. Further studies in a larger sample and over a longer time period is required to confirm these results.

Association between internet gaming addiction and leukocyte telomere length in Korean male adolescents

Internet gaming addiction (IGA) has been associated with many negative health outcomes, especially for youth. In particular, the potential association between IGA and leukocyte telomere length (LTL) has yet to be examined. In this study we compared LTL in Korean male adolescents with and without IGA and examined the association between LTL and autonomic functions. Specifically, plasma catecholamine, serum cortisol, and psychological stress levels were measured as autonomic functions. Data were collected using participant blood samples analyzed for LTL, catecholamine, and cortisol levels and a set of questionnaires to assess IGA and psychological stress levels of the participants. The LTL measurements were made using a qPCR-based technique, and the relative LTL was calculated as the telomere/single copy (T/S) ratio. T/S ratio was significantly shorter in the IGA group than in the non-IGA group (150.43 ± 6.20 and 187.23 ± 6.42, respectively; p < .001) after adjusting for age. In a univariate regression analysis, age, daily Internet gaming time, IGA score, and catecholamine level (epinephrine and norepinephrine) were significantly associated with T/S ratio. However, duration of Internet gaming exposure, dopamine, cortisol, and psychological stress levels were not found to be associated with T/S ratio. In the final multiple linear regression model, age, daily Internet gaming time, and epinephrine level showed statistically significant relationships with T/S ratio. Our results indicate that in addition to age, involvement in excessive Internet gaming may induce LTL shortening in male adolescents, which may be partially attributable to changes in autonomic function such as catecholamine level. These findings further understanding of the health effects of IGA and highlight the need for screening and intervention strategies for male adolescents with IGA.

Exercise, Telomeres, and Cancer: "The Exercise-Telomere Hypothesis"

Telomeres are genomic complex at the end of chromosomes that protects the DNA and telomere length (TL) is related to several age-related diseases, lifespan, and cancer. On the other hand, cancer is a multifactorial disease that is responsible for reduce the quality of life and kills millions of people every year. Both, shorter TL and cancer are related and could be treated or prevented depending of the lifestyle. In this review we discuss the possible role of exercise in the relationship between shorter telomeres, telomerase activity, and cancer. In summary, there is evidence that exercise leads to less telomere attrition and exercise also may diminish the risk of cancer, these two outcomes are possible intermediated by a reduction in oxidative stress, and chronic inflammation. Although, there is evidence that shorter TL are associated with cancer, the possible mechanisms that one may lead to the other remains to be clarified. We assume that humans under cancer treatment may suffer a great decrease in quality of life, which may increase sedentary behavior and lead to increased telomere attrition. And those humans with already shorter TL likely lived under a poor lifestyle and might have an increased risk to have cancer.

Physical Activity and Nutrition: Two Promising Strategies for Telomere Maintenance?

As the world demographic structure is getting older, highlighting strategies to counteract age-related diseases is a major public health concern. Telomeres are nucleoprotein structures that serve as guardians of genome stability by ensuring protection against both cell death and senescence. A hallmark of biological aging, telomere health is determined throughout the lifespan by a combination of both genetic and non-genetic influences. This review summarizes data from recently published studies looking at the effect of lifestyle variables such as nutrition and physical activity on telomere dynamics.

Методика підготовки спортсменів в сучасному спортивному фітнесі із застосуванням ізометричної гімнастики і кардіо-навантажень на початковому етапі

Мета роботи – виявити вплив застосування статичних вправ і ізометричної гімнастики у поєднанні з кардіо-навантаженнями в тренувальному процесі в спортивному фітнесі на показники силових можливостей, процесів відновлення. Матеріал і методи. В дослідженні взяли участь 40 чоловіків віком 20-25 років, маса тіла яких знаходилась в межах 65-75 кг, та 62 жінки віком 20-25 років, маса тіла яких знаходилась в діапазоні 55-90 кг. Чоловіки були поділені на контрольну та експериментальну групи по 20 осіб в кожній. Групи тренувалися за однаковими програмами, але в експериментальній групі менше часу приділялось застосуванню засобів силової витривалості на користь засобам, що розвивають серцево-судинну систему та зв’язковий апарат. В групі жінок у зв’язку з великим розкидом показників маси тіла і різного стажу було проведено тестування за пробою Лєтунова. Результати. Розроблено методику, що містить комплекси статичних вправ і ізометричної  гімнастики у поєднанні з кардіо-навантаженнями та дихальними вправами. Розроблена методика позитивно впливає на розвиток силових здібностей, на показники відновлення працездатності і на розумову працездатність. У жінок було виявлено достовірний вплив маси тіла у поєднанні із стажем занять фітнесом на показники ЧСС при відновленні після виконання проби Лєтунова на першій та на п’ятій хвилинах відновлення, а також на показники ЧСС в стані спокою. Оптимальна маса тіла сприяє поліпшенню тренувального ефекту у жінок при заняттях фітнесом. Висновки. В тренувальному процесі в сучасному фітнесі на початковому етапі підготовки варто застосовувати методику комплексного впливу на розвиток силових здібностей, зв’язкового апарату, серцево-судинної та нервової систем. Індивідульний підхід до тренувань жінок на початковому етапі підготовки повинен передбачати різний вплив стажу занять фітнесом на процеси відновлення у жінок з різною масою тіла.

Exercise rescues the immune response fine-tuned impaired by peroxisome proliferator-activated receptors γ deletion in macrophages

BACKGROUND

Exercise is a powerful tool for prevention and treatment of many conditions related to the cardiovascular system and also chronic low-grade inflammation. Peroxisome proliferator-activated receptors γ (PPARγ) exerts an import role on the regulation of metabolic profile and subsequent inflammatory response, especially in macrophages.

PURPOSE

To investigate the effects of 8-week moderate-exercise training on metabolic and inflammatory parameters in mice with PPARγ deficiency in myeloid cells.

METHODS

Twelve-week old mice bearing PPARγ deletion exclusively in myeloid cells (PPARγlox/lox Lys Cre ^-/+ , knockout [KO]) and littermate controls (PPARγlox/lox Lys Cre ^-/- , wild type [WT]) were submitted to 8-week exercise training (treadmill running at moderate intensity, 5 days/week). Animals were evaluated for food intake, glucose homeostasis, serum metabolites, adipose tissue and peritoneal macrophage inflammation, and basal and stimulated cytokine secretion.

RESULTS

Exercise protocol did not improve glucose metabolism or adiponectin concentrations in serum of KO mice. Moreover, the absence of PPARγ in macrophages exacerbated the proinflammatory profile in sedentary mice. Peritoneal cultured cells had higher tumor necrosis factor-α (TNF-α) secretion in nonstimulated and lipopolysaccharide (LPS)-stimulated conditions and higher Toll-4 receptor (TLR4) gene expression under LPS stimulus. Trained mice showed reduced TNF-α content in adipose tissue independently of the genotype. M2 polarization ability was impaired in KO peritoneal macrophages after exercise training, while adipose tissue-associated macrophages did not present any effect by PPARγ ablation.

CONCLUSION

Overall, PPARγ seems necessary to maintain macrophages appropriate response to inflammatory stimulus and macrophage polarization, affecting also whole body lipid metabolism and adiponectin profile. Exercise training showed as an efficient mechanism to restore the immune response impaired by PPARγ deletion in macrophages.

Leukocyte telomere length in the Thoroughbred racehorse

Thoroughbred racehorses possess superior cardiorespiratory fitness levels and are at the pinnacle of athletic performance compared to other breeds of horses. Although equine athletes have undergone years of artificial selection for racing performance, musculoskeletal injuries and illnesses are common and concerns relating to animal welfare have been proposed. Leukocyte telomere length is indicative of biological age, and accelerated telomere shortening occurs with excess physical and psychological stress. This study was designed to explore the association between leukocyte telomere length, biological factors (age, sex and coat colour), training status, winnings and race history parameters. Blood was collected from 146 Thoroughbred racehorses from around Geelong, Victoria, Australia. DNA was extracted from leukocytes; telomere length was measured using qPCR and analysed in context with traits obtained from the Racing Australia website. Age was inversely correlated with telomere length (r = -0.194, P = 0.019). The oldest horses (≥11 years) in the highest age quartile possessed shorter telomeres compared to younger horses in the first, second and third quartiles (≤2, 3-5 and 6-10 years respectively; P < 0.05). No statistically significant associations were observed between telomere length and biological factors, training status, winnings or race history parameters in age-adjusted analyses. The study findings suggest that Thoroughbred horses may undergo age-related telomere shortening similar to other mixed breeds and humans. Despite concerns from some quarters regarding the welfare of racehorses, there was a lack of accelerated biological ageing observed in the present study, as indicated by leukocyte telomere length.

Why are there associations between telomere length and behaviour?

Individual differences in telomere length are associated with individual differences in behaviour in humans and birds. Within the human epidemiological literature this association is assumed to result from specific behaviour patterns causing changes in telomere dynamics. We argue that selective adoption-the hypothesis that individuals with short telomeres are more likely to adopt specific behaviours-is an alternative worthy of consideration. Selective adoption could occur either because telomere length directly affects behaviour or because behaviour and telomere length are both affected by a third variable, such as exposure to early-life adversity. We present differential predictions of the causation and selective adoption hypotheses and describe how these could be tested with longitudinal data on telomere length. Crucially, if behaviour is causal then it should be associated with differential rates of telomere attrition. Using smoking behaviour as an example, we show that the evidence that smoking accelerates the rate of telomere attrition within individuals is currently weak. We conclude that the selective adoption hypothesis for the association between behaviour and telomere length is both mechanistically plausible and, if anything, more compatible with existing empirical evidence than the hypothesis that behaviour is causal.This article is part of the theme issue 'Understanding diversity in telomere dynamics'.