Telomere dysfunction: a potential cancer predisposition factor

Leukocyte telomere length serves as the novel prognostic biomarker for the resectable NSCLC

The relationship of Leukocyte telomere length (LTL) dynamic changes with resectable NSCLC progression remains unclear. This study aims to reveal its clinical utility for prognosis of the resectable NSCLC. LTL was measured in 76 resectable NSCLC patients and 80 healthy controls using peripheral blood samples. Pre-operation LTL (Pre-LTL) and post-operation LTL (Po-LTL) were analyzed in relation to TNM stage, metastasis, and survival outcomes. The prognostic value was evaluated by disease-free survival (DFS) and overall survival (OS). NSCLC patients had significantly shorter LTL compared to controls, with LTL inversely correlated to disease stage. Po-LTL increased significantly and was associated with better OS. Combining Po-LTL with TNM stage improved prognostic prediction for OS and DFS. LTL is a promising biomarker for predicting prognosis in resectable NSCLC. Po-LTL, as well as in combination with TNM stage, enhances predictive accuracy for OS and DFS.

Evaluating the Effect of Telomere Length on Oral and Oropharyngeal Cancer Risk Using Mendelian Randomization

INTRODUCTION

The aim of this study was to explore the causal relationship between telomere length and Oral and oropharyngeal cancers by using Mendelian randomization (MR) analysis.

METHODS

We carried out a 2-sample MR to examine the causal association between telomere length and Oral and oropharyngeal cancers. Two large genome-wide association studies (GWAS) were employed to identify single nucleotide polymorphisms (SNPs) as instrumental variables through statistical and biological approaches. The data on SNP-oral and oropharyngeal cancer risk factor associations were sourced from various consortia/UK Biobank. The inverse variance weighted (IVW) method was employed as the primary approach for overall causal estimation in MR, with sensitivity analyses conducted to assess potential confounding by pleiotropy, heterogeneity, and the leave-one-out analysis.

RESULTS

The statistically driven approach indicates limited evidence of a genetically causal effect of telomere length on the risk of oral cavity cancer (OR = 0.999, 95% CI 0.998-1.000, P = .100), oropharyngeal cancer (OR = 0.999, 95% CI 0.998-1.001, P = .650), combined oral and oropharyngeal cancer (OR = 0.999, 95% CI 0.998-1.000, P = .119) in Europeans. The biologically driven approach demonstrated consistent causal effects across all MR methods, thereby further strengthening the reliability of the results. Moreover, the MR-Egger (Q [df] 170.816 [130], P = .009) and inverse variance weighted methods (Q [df] 171.656 [131], P = .010) identified considerable heterogeneity among instrumental variable estimates in Oral cavity cancer, and no evidence of horizontal pleiotropy was detected.

CONCLUSIONS

No significant causal associations between telomere length and Oral and oropharyngeal cancers were found in this study.

Decoding the mechanisms behind second primary cancers

Second Primary Cancers (SPCs) are defined as cancers that develop either simultaneously or metachronously in the same individual who has been diagnosed with and survived one primary cancer. SPCs exhibit a high incidence rate and represent the primary cause of mortality among survivors of first primary cancers. There is growing concern about the dangers of SPCs. This review summarizes recent studies on the mechanisms of SPCs, including the roles of genomic changes after first primary cancer (FPC) treatments, stromal cell phenotypic and metabolic changes, hormone levels and receptor expression, immunosuppression, aberrant gene methylation, EGFR signaling, and cell-free DNA in SPC development. This comprehensive analysis contributes to elucidating current research trends in SPC mechanisms and enhances our understanding of the underlying pathophysiology. Furthermore, potential applications of intratumoral microbes, single-cell multi-omics, and metabolomics in investigating SPC mechanisms are also discussed, providing new ideas for follow-up studies.

Silica-exposed patients with silicosis show shorter telomeres than do unexposed individuals: a pilot study in a population in southeastern Brazil

OBJECTIVE

Silicosis is a pneumoconiosis characterized by fibrosis of the lung parenchyma caused by the inhalation of silica particles. Silica dust inhalation is associated with inflammation and induction of oxidative stress in the lungs. This oxidative stress affects telomeres, which are short tandem DNA repeats that cap the end of linear chromosomes. We aimed to determine whether telomere length (TL) correlates with silicosis or severity of silicosis in silica-exposed workers in Brazil.

METHODS

We included 200 men in southeastern Brazil: 100 with silicosis and 100 who had not been exposed to silica. We extracted DNA from buccal cells and assessed TL by multiplex quantitative polymerase chain reaction.

RESULTS

The median TL was significantly shorter in the patients with silicosis than in the unexposed controls (p < 0.0001), although it did not differ between the patients with simple silicosis and those with complicated silicosis (p = 0.961). We also found that, in patients with silicosis, TL was influenced by smoking (p = 0.034) and by a history of personal protective equipment use in the workplace (p = 0.002).

CONCLUSIONS

Silica exposure appears to have an impact on TL, which was found to be shorter in patients with silicosis than in unexposed controls. Further studies are needed in order to confirm the impact that oxidative stress caused by silica inhalation has on telomeres.

Circulating TERT serves as the novel diagnostic and prognostic biomarker for the resectable NSCLC

BACKGROUND

Telomerase reverse transcriptase (TERT) is a catalytic subunit of telomerase and required for cancer development. This study aims to reveal its clinical utility for diagnosis and prognosis of resectable NSCLC.

METHODS

TERT was quantitatively evaluated by the enzyme-linked immunosorbent assay (ELISA) from 69 patients before and after the surgery. The prognostic value was evaluated by disease-free survival (DFS) and overall survival (OS).

RESULTS

Circulating TERT in NSCLC patients were significantly higher than that in the healthy group, possessing the AUC of 0.90. Importantly, TERT change between pre- and post- operation was significantly correlated with OS and DFS (p = 0.022, p = 0.046 respectively), acted as the independent prognostic factors for DFS and OS, indicating it can serve as the promising diagnostic and prognostic biomarker for resectable non-small cell lung cancer (NSCLC).

CONCLUSIONS

TERT change between pre- and post- resection can serve as the promising biomarker for prognosis of resectable NSCLC.

Micronutrient intake and telomere length: findings from the UK Biobank

PURPOSE

To investigate whether micronutrient intake from food as well as the regular uptake of specific vitamins and/or minerals are associated with leucocyte telomere length (LTL).

METHODS

This is a cross-sectional study using data from 422,693 UK Biobank participants aged from 40 to 69 years old, during 2006-2010. LTL was measured as the ratio of telomere repeat number to a single-copy gene and was loge-transformed and z-standardized (z-LTL). Information concerning supplement use was collected at baseline through the touchscreen assessment, while micronutrient intake from food were self-reported through multiple web-based 24 h recall diaries. The association between micronutrient intake or supplement use and z-LTL was assessed using multivariable linear regression models adjusting for demographic, lifestyle and clinical characteristics.

RESULTS

About 50% (n = 131,810) of the participants, with complete data on all covariates, self-reported regular supplement intake. Whilst overall supplement intake was not associated with z-LTL, trends toward shorter z-LTL with regular vitamin B (-0.019 (95% CI: -0.041; 0.002)) and vitamin B9 (-0.027 (-0.054; 0.000)) supplement intake were observed. z-LTL was associated with food intake of pantothenic acid (-0.020 (-0.033; -0.007)), vitamin B6 (-0.015 (-0.027; -0.003)), biotin (0.010 (0.002; 0.018)) and folate (0.016 (0.003; 0.030)). Associations of z-LTL with these micronutrients were differentiated according to supplement intake.

CONCLUSION

Negative associations equivalent to a year or less of age-related change in LTL between micronutrient intake and LTL were observed. Due to this small effect, the clinical importance of the associations and any relevance to the effects of vitamin and micronutrient intake toward chronic disease prevention remains uncertain.

Leukocytes telomere length as a biomarker of adverse drug reactions induced by Osimertinib in advanced non-small cell lung cancer

This study aimed to measure relative telomere length (RTL) in blood leukocytes of advanced-stage NSCLC patients either with or without Osimertinib-induced ADRs and determine whether RTL could serve as a biomarker of Osimertinib-induced ADRs. Blood leukocytes RTL were measured in 63 advanced-stage NSCLC patients and 62 age-matched healthy controls using real-time polymerase chain reaction. In patients with advanced-stage NSCLC, RTL was significantly shorter than that in healthy controls (P < 0.001). Compared to patients without ADRs and those with mild/moderate ADRs, patients with severe ADRs exhibited significantly decreased RTL (P < 0.001, P < 0.001, respectively). ROC curve analysis uncovered a diagnostic value of RTL as a biomarker of Osimertinib-induced ADRs (AUC = 1.000, P < 0.001). Kaplan-Meier analysis revealed a significant association between shorter RTL and increased cumulative incidence of Osimertinib-induced ADRs in patients with advanced-stage NSCLC (P < 0.001). Shorter RTL in blood leukocytes would reflect the occurrence of Osimertinib-induced ADRs and might emerge as a promising biomarker for identifying advanced-stage NSCLC patients who are at risk of experiencing Osimertinib-induced ADRs, particularly those with severe ADRs.

Connecting the Dots: Telomere Shortening and Rheumatic Diseases

Telomeres, repetitive sequences located at the extremities of chromosomes, play a pivotal role in sustaining chromosomal stability. Telomerase is a complex enzyme that can elongate telomeres by appending telomeric repeats to chromosome ends and acts as a critical factor in telomere dynamics. The gradual shortening of telomeres over time is a hallmark of cellular senescence and cellular death. Notably, telomere shortening appears to result from the complex interplay of two primary mechanisms: telomere shelterin complexes and telomerase activity. The intricate interplay of genetic, environmental, and lifestyle influences can perturb telomere replication, incite oxidative stress damage, and modulate telomerase activity, collectively resulting in shifts in telomere length. This age-related process of telomere shortening plays a considerable role in various chronic inflammatory and oxidative stress conditions, including cancer, cardiovascular disease, and rheumatic disease. Existing evidence has shown that abnormal telomere shortening or telomerase activity abnormalities are present in the pathophysiological processes of most rheumatic diseases, including different disease stages and cell types. The impact of telomere shortening on rheumatic diseases is multifaceted. This review summarizes the current understanding of the link between telomere length and rheumatic diseases in clinical patients and examines probable telomere shortening in peripheral blood mononuclear cells and histiocytes. Therefore, understanding the intricate interaction between telomere shortening and various rheumatic diseases will help in designing personalized treatment and control measures for rheumatic disease.

Leucocyte Telomere Length and Lung Cancer Risk: A Systematic Review and Meta-Analysis of Prospective Studies

Although numerous epidemiological studies are available, the relationship between leukocyte telomere length (LTL) and lung cancer risk is still controversial. This systematic review and meta-analysis, performed according to the PRISMA statement and MOOSE guidelines, aims to summarize the evidence and calculate the risk of lung cancer associated with LTL. The literature search was performed on PubMed, Web of Science, and Scopus databases through May 2024. A random-effects model was used to calculate the pooled risk. Heterogeneity was assessed using I2 and Cochran's Q statistic. Begg's and Egger's tests were used to detect publication bias. Based on 8055 lung cancer cases and 854,653 controls (nine prospective studies), longer LTL was associated with a significant 42% increment in all types of lung cancer risk (OR 1.42, 95% CI 1.24-1.63). The effect was even more evident for adenocarcinomas (OR 1.98, 95% CI 1.69-2.31), while no association was observed for squamous cell carcinoma (OR 0.87, 95% CI 0.72-1.06). Significantly, no association was found for current smokers (OR 1.08, 95% CI 0.90-1.30), while it remained high for both never-smokers (OR 1.92, 95% CI 1.62-2.28) and former smokers (OR 1.34, 95% CI 1.11-1.62). No significant publication bias was evidenced. Longer LTL is associated with an increment in lung cancer risk particularly in never-smoker subjects.

Physical Performance and Telomere Length in Older Adults

BACKGROUND

The aging population prompts studying risk factors and markers to predict healthy aging. Telomere length is a promising candidate for assessing various age-related traits.

AIM OF THE STUDY

To investigate the association between physical performance and telomere length.

METHODS

We enrolled 323 older Mexican adults from the "Cohort of Obesity, Sarcopenia, and Frailty of Older Mexican Adults" affiliated with the Instituto Mexicano del Seguro Social and assessed their physical performance using the Short Physical Performance Battery, dividing participants into low (≤7) and high (>7) groups. Absolute telomere length was determined by qPCR, and individuals were classified into short (≤4.22 kb) and long (>4.22 kb) groups. We calculated the mean and adjusted mean, considering sex and age, among others, with 95% CI. We estimated the effect size between physical performance and telomere length using Cohen's d for unequal group sizes and calculated the odds ratio for physical performance based on telomere length.

RESULTS

Participants with low physical performance had significantly shorter telomeres (mean 4.14.44.7 kb, adjusted mean 3.54.04.5 kb, p <0.001), while those with high physical performance exhibited longer telomeres (mean 5.55.75.9 kb, adjusted mean 4.75.35.8 kb, p <0.001), with a medium-to-high telomere length effect size (d = 0.762). The odds of low physical activity increased 2.13.66.1-fold per kb of telomere attrition (adjOR 1.73.36.3, p <0.001).

CONCLUSION

Decreased physical function is associated with shorter telomere length. Absolute telomere length presents a promising biomarker for distinguishing between healthy and unhealthy aging, warranting further investigation.

The Association between Telomere Length and Head and Neck Cancer Risk: A Systematic Review and Meta-Analysis

Telomeres play a crucial role in maintaining chromosomal integrity and regulating the number of cell divisions and have been associated with cellular aging. Telomere length (TL) has been widely studied in manifold cancer types; however, the results have been inconsistent. This systematic review and meta-analysis aims to analyze the evidence on the association between TL and head and neck cancer (HNC) risk. We comprehensively searched the literature in PubMed, Cochrane Library, and Scopus and identified nine eligible studies, which yielded 11 datasets. The odds ratios (ORs) and 95% confidence intervals (CIs) were used to ascertain the strength of the association. On the basis of the median TL, we defined two groups, short TL and long TL, with the latter being the reference group. Our analysis found a significant relationship between short TL and increased HNC risk (OR 1.38, 95% CI: 1.10-1.73, p = 0.005), while significant heterogeneity among the studies was noted. The subgroup analysis on HNC subtypes revealed a significant association between short TL and oral cancers (OR 2.08, 95% CI: 1.23-3.53, p = 0.007). Additionally, subgroup analysis indicates that adjustments for age, sex, and smoking did not affect the significance of our findings. In conclusion, our meta-analysis found evidence for an association between short TL and HNC risk, which could indicate that TL might act as a potential biomarker for HNC risk, but high-quality prospective studies are imperative to validate our findings.

DNA methylation-based telomere length is associated with HIV infection, physical frailty, cancer, and all-cause mortality

Telomere length (TL) is an important indicator of cellular aging. Shorter TL is associated with several age-related diseases including coronary heart disease, heart failure, diabetes, osteoporosis, and cancer. Recently, a DNA methylation-based TL (DNAmTL) estimator has been developed as an alternative method for directly measuring TL. In this study, we examined the association of DNAmTL with cancer prevalence and mortality risk among people with and without HIV in the Veterans Aging Cohort Study Biomarker Cohort (VACS, N = 1917) and Women's Interagency HIV Study Cohort (WIHS, N = 481). We profiled DNAm in whole blood (VACS) or in peripheral blood mononuclear cells (WIHS) using an array-based method. Cancer prevalence was estimated from electronic medical records and cancer registry data. The VACS Index was used as a measure of physiologic frailty. Models were adjusted for self-reported race and ethnicity, batch, smoking status, alcohol consumption, and five cell types (CD4, CD8, NK, B cell, and monocyte). We found that people with HIV had shorter average DNAmTL than those without HIV infection [beta = -0.25, 95% confidence interval (-0.32, -0.18), p = 1.48E-12]. Greater value of VACS Index [beta = -0.002 (-0.003, -0.001), p = 2.82E-05] and higher cancer prevalence [beta = -0.07 (-0.10, -0.03), p = 1.37E-04 without adjusting age] were associated with shortened DNAmTL. In addition, one kilobase decrease in DNAmTL was associated with a 40% increase in mortality risk [hazard ratio: 0.60 (0.44, 0.82), p = 1.42E-03]. In summary, HIV infection, physiologic frailty, and cancer are associated with shortening DNAmTL, contributing to an increased risk of all-cause mortality.

Biological basis and treatment of frailty and sarcopenia

In an ageing society, the importance of maintaining healthy life expectancy has been emphasized. As a result of age-related decline in functional reserve, frailty is a state of increased vulnerability and susceptibility to adverse health outcomes with a serious impact on healthy life expectancy. The decline in skeletal muscle mass and function, also known as sarcopenia, is key in the development of physical frailty. Both frailty and sarcopenia are highly prevalent in patients not only with advanced age but also in patients with illnesses that exacerbate their progression like heart failure (HF), cancer, or dementia, with the prevalence of frailty and sarcopenia in HF patients reaching up to 50-75% and 19.5-47.3%, respectively, resulting in 1.5-3 times higher 1-year mortality. The biological mechanisms of frailty and sarcopenia are multifactorial, complex, and not yet fully elucidated, ranging from DNA damage, proteostasis impairment, and epigenetic changes to mitochondrial dysfunction, cellular senescence, and environmental factors, many of which are further linked to cardiac disease. Currently, there is no gold standard for the treatment of frailty and sarcopenia, however, growing evidence supports that a combination of exercise training and nutritional supplement improves skeletal muscle function and frailty, with a variety of other therapies being devised based on the underlying pathophysiology. In this review, we address the involvement of frailty and sarcopenia in cardiac disease and describe the latest insights into their biological mechanisms as well as the potential for intervention through exercise, diet, and specific therapies.

Telomere length is associated with increased risk of cutaneous melanoma: a Mendelian randomization study

RESULTS

The MR analysis using two TL GWAS datasets revealed strong and consistent evidence that long TL is causally associated with an increased risk of CM. The analysis of the Codd et al. dataset found that long TL significantly predicted an elevated risk of CM (IVW OR = 2.411, 95% CI 2.092-2.780, P = 8.05E-34). Similarly, the analysis of the Li et al. dataset yielded consistent positive results across all MR methods, providing further robustness to the causal relationship (IVW OR = 2.324, 95% CI 1.516-3.565, P = 1.11E-04). The study provides evidence for a causal association between TL and CM susceptibility, indicating that longer TL increases the risk of developing CM and providing insight into the unique telomere biology in melanoma pathogenesis. Telomere maintenance pathways may be a potential target for preventing and treating CM.

Depressive symptoms and shorter survival in lung cancer: the role of leukocyte telomere length

OBJECTIVE

To examine the association between depressive symptoms, leukocyte telomere length-a marker of cellular ageing, and survival amongst lung cancer patients.

DESIGN

Patients with non-small cell lung cancer were recruited from a university-affiliated cancer center clinic.

MAIN OUTCOME

Patients (N = 67) reported on depressive symptoms and provided a blood sample for leukocyte telomere length assessment at baseline and at a 3-month follow-up. Survival status was tracked over 3 years.

RESULTS

Age at diagnosis and depressive symptoms, as measured by the CES-D, were associated with shorter leukocyte telomere length (p < .05), although only age at diagnosis contributed statistical significance to the model. Depressive symptoms predicted shorter survival from date of diagnosis (p < .01). Patients who reported experiencing clinically meaningful levels of depressive symptoms (CES-D scores ≥ 16) demonstrated shorter survival than those who reported sub-clinical levels of depressive symptoms (p < .05). Leukocyte telomere length did not emerge as a predictor of shorter survival.

CONCLUSION

Clinically meaningful levels of depressive symptoms are associated with shorter survival amongst lung cancer patients. These findings support the on-going efforts to screen all cancer patients for low mood and to investigate mechanisms linking depressive symptoms and shorter survival in cancer contexts.

Association of telomere length with risk of lung cancer: A large prospective cohort study from the UK Biobank

OBJECTIVES

Leukocyte telomere length (LTL) is associated with a wide variety of diseases, including cancer. However, findings regarding the association between LTL and the risk for lung cancer have been inconclusive and inconsistent across previous observational studies.

METHODS

This prospective cohort study included data from 425,146 participants 37-73 years of age housed in the UK Biobank. Quantitative polymerase chain reaction (qPCR) was used to measure LTL in baseline DNA samples. A multivariate Cox proportional hazards model was used to evaluate the relationship between LTL and the risk for lung cancer.

RESULTS

An increase in LTL per interquartile range (IQR) was associated with a 9% increase in the risk for lung cancer (hazard ratio [HR] 1.09 [95% confidence interval (CI) 1.03-1.16]). Participants in the highest LTL quintile exhibited an approximately 25% elevated risk for developing lung cancer (HR 1.25 [95% CI 1.09-1.45]) compared with those in the lowest quintile. The relationship between per IQR increase in LTL and elevated risk for lung cancer was greater in the histological subtype of adenocarcinoma (HR 1.30 [95% CI 1.18-1.43]), female sex (HR 1.16 [95% CI 1.06-1.26]), non-smokers (HR 1.45 [95% CI 1.23-1.71]), and individuals with high genetic risk for lung cancer (HR 1.18 [95% CI 1.03-1.34]), respectively. Surprisingly, a per IQR increase in LTL was associated with increased risks for both lung adenocarcinoma (HR 1.56 [95% CI 1.24-1.96]) and squamous cell carcinoma (HR 2.01 [95% CI 1.13-3.56]) in never smokers.

CONCLUSIONS

Longer LTL was associated with an elevated risk for lung cancer, particularly for adenocarcinoma and squamous cell carcinoma in never smokers. The results suggest the potential of telomeres as non-invasive biomarkers for the early screening of lung cancer, particularly in non-smokers, who are typically overlooked.

Associations between telomere attrition, genetic variants in telomere maintenance genes, and non-small cell lung cancer risk in the Jammu and Kashmir population of North India

BACKGROUND

Telomeres are repetitive DNA sequences located at the ends of chromosomes, playing a vital role in maintaining chromosomal integrity and stability. Dysregulation of telomeres has been implicated in the development of various cancers, including non-small cell lung cancer (NSCLC), which is the most common type of lung cancer. Genetic variations within telomere maintenance genes may influence the risk of developing NSCLC. The present study aimed to evaluate the genetic associations of select variants within telomere maintenance genes in a population from Jammu and Kashmir, North India, and to investigate the relationship between telomere length and NSCLC risk.

METHODS

We employed the cost-effective and high-throughput MassARRAY MALDI-TOF platform to assess the genetic associations of select variants within telomere maintenance genes in a population from Jammu and Kashmir, North India. Additionally, we used TaqMan genotyping to validate our results. Furthermore, we investigated telomere length variation and its relation to NSCLC risk in the same population using dual-labeled fluorescence-based qPCR.

RESULTS

Our findings revealed significant associations of TERT rs10069690 and POT1 rs10228682 with NSCLC risk (adjusted p-values = 0.019 and 0.002, respectively), while TERF2 rs251796 and rs2975843 showed no significant associations. The TaqMan genotyping validation further substantiated the associations of TERT rs10069690 and rs2242652 with NSCLC risk (adjusted p-values = 0.02 and 0.003, respectively). Our results also demonstrated significantly shorter telomere lengths in NSCLC patients compared to controls (p = 0.0004).

CONCLUSION

This study highlights the crucial interplay between genetic variation in telomere maintenance genes, telomere attrition, and NSCLC risk in the Jammu and Kashmir population of North India. Our findings suggest that TERT and POT1 gene variants, along with telomere length, may serve as potential biomarkers and therapeutic targets for NSCLC in this population. Further research is warranted to elucidate the underlying mechanisms and to explore the potential clinical applications of these findings.

Telomere Shortening of Barrett's Esophagus and Esophageal Adenocarcinoma in Japanese Patients

Telomere shortening is deeply involved in many types of cancer. Telomere length of esophageal adenocarcinoma (EAC) and Barrett's esophagus (BE) was examined in Japanese patients. Among BE from cancer free patients (Cancer free), BE from patients with EAC (Adjacent) and EAC tissue (Cancer), Cancer free group presented the longest telomeres, while Cancer group presented the shortest telomeres and Adjacent group presented intermediate telomeres. Direction of endoscopic biopsy, 2 o'clock direction was also significantly associated with shorter telomere length in non-neoplastic BE (p = 0.027). Shortened telomere highlighted the impact of this molecular change in early carcinogenesis in EAC.

Weight Change over Ten Years Predicts Biological Aging in a Random Sample of 3070 U.S. Adults

This investigation was designed to study the relationship between weight change over 10 years and leukocyte telomere length (LTL) in a large sample of 3070 randomly selected U.S. adults, 36-70 years old. The National Health and Nutrition Examination Survey (NHANES) data were used to examine the relationship between percent weight change and LTL. Potential mediating variables were controlled using partial correlation. After adjusting for age, race, year, and housing status, the association between percent weight change over 10 years and LTL was significant in women (F = 6.9, p = 0.0138). Adjusting for the demographic and several other covariates weakened the relationship slightly (F = 4.7, p = 0.0392). With all the covariates controlled, for each one percentage point increase in weight over the previous 10 years, telomeres were, on average, 3.48 base pairs (bp) shorter in women. Given that each one-year increase in age was associated with telomeres that were 15.0 bp shorter in women, the median weight change in U.S. women over the previous 10 years (an increase of 10.4%) was predictive of LTLs that were 36 bp shorter, on average, or an increase of 2.4 years of biological aging. Percent weight change over 10 years was not associated with LTL in U.S. men. Percent weight change over 10 years is a strong predictor of biological aging in U.S. women, but not in men.

Functional association between telomeres, oxidation and mitochondria

Prior research has substantiated the vital role of telomeres in human fertility. Telomeres are prerequisites for maintaining the integrity of chromosomes by preventing the loss of genetic material following replication events. Little is known about the association between sperm telomere length and mitochondrial capacity involving its structure and functions. Mitochondria are structurally and functionally distinct organelles that are located on the spermatozoon's midpiece. Mitochondria produce adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS), which is necessary for sperm motility and generate reactive oxygen species (ROS). While a moderate concentration of ROS is critical for egg-sperm fusion, and fertilization, excessive ROS generation is primarily related to telomere shortening, sperm DNA fragmentation, and alterations in the methylation pattern leading to male infertility. This review aims to highlight the functional connection between mitochondria biogenesis and telomere length in male infertility, as mitochondrial lesions have a damaging impact on telomere length, leading both to telomere lengthening and reprogramming of mitochondrial biosynthesis. Furthermore, it aims to shed light on how both inositol and antioxidants can positively affect male fertility.

Is Human Aging a Form of Phenoptosis?

A much debated question is whether aging is the cumulative consequence of degenerative factors insufficiently opposed by natural selection, or, on the contrary, an ordered process, genetically determined and regulated, modeled by natural selection, and for which the definition of phenoptotic phenomenon would be entirely appropriate. In this review, theoretical arguments and empirical data about the two hypotheses are exposed, with more evidence in support of the thesis of aging as a form of phenoptosis. However, as the thesis of aging as an adaptive and programmed phenomenon necessarily requires the existence of specific mechanisms that determine to age, such as the subtelomere-telomere theory proposed for this purpose, the evidence supporting the mechanisms described by this theory is reported. In particular, it is highlighted that the recent interpretation of the role of TERRA sequences in the context of subtelomere-telomere theory is a fundamental point in supporting the hypothesized mechanisms. Furthermore, some characteristics of the mechanisms proposed by the theory, such as epigenetic modifications in aging, gradual cell senescence, cell senescence, limits in cell duplications, and fixed size of the telomeric heterochromatin hood, are exposed in their compatibility with both the thesis of aging as phenoptotic phenomenon and the opposite thesis. In short, aging as a form of phenoptosis appears a scientifically sound hypothesis while the opposite thesis should clarify the meaning of various phenomena that appear to invalidate it.

Effects of air pollution on telomere length: Evidence from in vitro to clinical studies

Air pollution remains the major environmental problem globally. There is extensive evidence showing that the variety of air pollutants from environmental and occupational exposures cause adverse effects to our health. The clinical symptoms of those effects may present at a late stage, so surveillance is difficult to manage. Several biomarkers have been used for the early detection of health issues following exposure to air pollution, including the use of telomere length which indicates cellular senescence in response to oxidative stress. Oxidative stress is one of the most plausible mechanisms associated with exposure to air pollutants. Some specific contexts including age groups, gender, ethnicity, occupations, and health conditions, showed significant alterations in telomere length after exposure to air pollutants. Several reports demonstrated both negative and positive associations between telomere length and air pollution, the studies using different concentrations and exposure times to air pollution on the study of telomere lengths. Surprisingly, some studies reported that low levels of exposure to air pollutants (lower than regulated levels) caused the alterations in telomere length. Those findings suggest that telomere length could be one of most practical biomarkers in air pollution surveillance. Therefore, this review aimed to summarize and discuss the relationship between telomere length and exposure to air pollution. The knowledge from this review will be beneficial for the planning of public health to reduce health problems in the general population, particularly in vulnerable people, who still live in areas with high air pollution.

Gestational exposure to NO2 aggravates placental senescence

Placental senescence is a normal physiological process of placenta, while premature placental senescence has been confirmed to be associated with some adverse pregnancy complications. Epidemiological studies indicate that NO₂ exposure can aggravate placental senescence which is represented by fibrosis and abnormal telomere homeostasis, etc. In this study, pregnant C57BL/6 mice were exposed to NO₂ (2.5 ppm, 5 h/day) daily in a dynamic exposure chamber throughout the gestation period, and were sacrificed at embryonic day 13.5 (E13.5), E15.5 and E18.5. Placenta were harvested and conducted for histopathological examination and telomere evaluation. Our results showed that gestational NO₂ exposure significantly aggravated placental fibrosis and calcification, and up-regulated the related bio-markers (connective tissue growth factor (Ctgf) and transforming growth factor-β1 (Tgf-β1)) at E18.5. In addition, gestational exposure to NO₂ also activated senescence related pathway (p53/p21) at E18.5. Furthermore, gestational NO₂ exposure significantly shortened telomere length at E18.5, and the expression of telomere homeostasis regulation genes telomeric repeat binding factor 1 (Trf1), protection of telomeres 1a (Pot1a) and Pot1b were significantly increased while telomerase reverse transcriptase (Tert) was suppressed after NO₂ exposure at E13.5 or E18.5, respectively. Importantly, DNA methylation status of the 22^nd at E13.5 and 32^nd at E18.5 site in sub-telomeric region of chromosome 1 was significantly altered. Based on the above results, our present study indicated that gestational NO₂ exposure could lead to premature placental senescence during the late trimester of pregnancy via aggravation of fibrosis and telomere length shortening regulated by telomere regulatory enzyme and DNA methylation.

Fat metabolism is associated with telomere length in six population-based studies

Telomeres are repetitive DNA sequences located at the end of chromosomes, which are associated to biological aging, cardiovascular disease, cancer, and mortality. Lipid and fatty acid metabolism have been associated with telomere shortening. We have conducted an in-depth study investigating the association of metabolic biomarkers with telomere length (LTL). We performed an association analysis of 226 metabolic biomarkers with LTL using data from 11 775 individuals from six independent population-based cohorts (BBMRI-NL consortium). Metabolic biomarkers include lipoprotein lipids and subclasses, fatty acids, amino acids, glycolysis measures and ketone bodies. LTL was measured by quantitative polymerase chain reaction or FlowFISH. Linear regression analysis was performed adjusting for age, sex, lipid-lowering medication and cohort-specific covariates (model 1) and additionally for body mass index (BMI) and smoking (model 2), followed by inverse variance-weighted meta-analyses (significance threshold pmeta = 6.5x10-4). We identified four metabolic biomarkers positively associated with LTL, including two cholesterol to lipid ratios in small VLDL (S-VLDL-C % and S-VLDL-ce %) and two omega-6 fatty acid ratios (FAw6/FA and LA/FA). After additionally adjusting for BMI and smoking, these metabolic biomarkers remained associated with LTL with similar effect estimates. In addition, cholesterol esters in very small VLDL (XS-VLDL-ce) became significantly associated with LTL (p = 3.6x10-4). We replicated the association of FAw6/FA with LTL in an independent dataset of 7845 individuals (p = 1.9x10-4). To conclude, we identified multiple metabolic biomarkers involved in lipid and fatty acid metabolism that may be involved in LTL biology. Longitudinal studies are needed to exclude reversed causation.

Evaluating the association of self-reported psychological distress and self-rated health on survival times among women with breast cancer in the U.S

BACKGROUND

Psychological distress and self-rated health status may create additional complexities in patients already diagnosed with breast cancer. This study aims to assess the association of self-report-based assessment of psychological distress and self-rated health on survival times among women with breast cancer diagnoses.

METHODS

Seventeen-year data from the Integrated Public Use Microdata Series-National Health Interview Survey (IPUMS-NHIS) were pooled and analyzed. Women who were aged 30 to 64 years old, with breast cancer diagnosis were selected (n = 2,819). The outcome variable was time to death. The independent variables were self-reported assessment of psychological distress and self-rated health. Psychological distress was defined using the Kessler-6 scale while self-rated health was measured on a 3-point Likert scale: Poor, Fair, and Good-to-Excellent (referred to as good for brevity). We computed unadjusted and adjusted hazard ratios (HR) using Cox-Proportional Hazard regression models with sociodemographic characteristics and measures of health care access used as potential confounders. Significance was set at alpha = 0.05.

RESULTS

Women with breast cancer assessed as having psychological distress had 46% (Adjusted HR: 1.46; 95% CI: 1.02-2.09) increased risks of mortality. Also, women who rated their health as poor or fair had a significantly elevated mortality risk (Poor Health: Adjusted HR: 3.05; 95% CI: 2.61-4.69; Fair Health: Adjusted HR: 1.83; 95% CI: 1.43-2.35) as compared to women with good health status.

CONCLUSIONS

Self-reported psychological distress and fair and poor self-rated health are associated with reduced survival times among women with breast cancer diagnoses.

Long- and Short-Term Exposures to PM10 Can Shorten Telomere Length in Individuals Affected by Overweight and Obesity

Reduced telomere length (TL) has been associated with increased risk of age-related diseases, most likely through oxidative stress and inflammation, which have also been claimed as mechanisms underlying health effects of air pollution exposure. We aimed to verify whether exposure to particulate matter with diameter ≤10 µm (PM₁₀) affects TL. We recruited 1792 participants with overweight/obesity in Milan (Italy) in 2010-2015 who completed a structured questionnaire on sociodemographic data, gave a blood sample for TL measurement by real-time PCR, and were assigned air pollution and meteorological data of their residential address. In multivariate mixed-effects linear models (with a random intercept on PCR plate), we observed a -0.51% change in TL (95% confidence interval (CI): -0.98; -0.05)) per 10 µg/m³ increase in PM₁₀ at the day of recruitment. A similar decreasing trend in TL was observed up to two weeks before withdrawal, with percentage changes as low as -1.53% (average exposure of the 12 days before recruitment). Mean annual exposure to PM₁₀ was associated with -2.57% TL reduction (95%CI: -5.06; -0.08). By showing consistent associations between short- and long-term PM₁₀ exposures and reduced TL, our findings shed light on the potential mechanisms responsible for the excess of age-related diseases associated with air pollution exposure.

Association of Mitochondrial DNA Copy Number and Telomere Length with Prevalent and Incident Cancer and Cancer Mortality in Women: A Prospective Swedish Population-Based Study

Changes in mitochondrial DNA copy number (mtDNA-CN) and telomere length have, separately, been proposed as risk factors for various cancer types. However, those results are conflicting. Here, mtDNA-CN and relative telomere length were measured in 3225 middle-aged women included in a large population-based prospective cohort. The baseline mtDNA-CN in patients with prevalent breast cancer was significantly higher (12.39 copies/µL) than cancer-free individuals. During an average of 15.2 years of follow-up, 520 patients were diagnosed with cancer. Lower mtDNA-CN was associated with decreased risk of genital organ cancer (hazard ratio (HR), 0.84), and shorter telomere length was associated with increased risk of urinary system cancer (HR, 1.79). Furthermore, mtDNA-CN was inversely associated with all-cause (HR, 1.20) and cancer-specific mortality (HR, 1.21) when considering all cancer types. Surprisingly, shorter telomere length was associated with decreased risk of cancer-specific mortality when considering all cancer types (HR, 0.85). Finally, lower mtDNA-CN and shorter telomere length were associated with increased risk of both all-cause and cancer-specific mortality in genital organ cancer patients. In this study population, we found that mtDNA-CN and telomere length were significantly associated with prevalent and incident cancer and cancer mortality. However, these associations were cancer type specific and need further investigation.

Telomere Length in Chromosomally Normal and Abnormal Miscarriages and Ongoing Pregnancies and Its Association with 5-hydroxymethylcytosine Patterns

The present study investigates telomere length (TL) in dividing chorionic cytotrophoblast cells from karyotypically normal and abnormal first trimester miscarriages and ongoing pregnancies. Using Q-FISH, we measured relative TLs in the metaphase chromosomes of 61 chorionic villous samples. Relative TLs did not differ between karyotypically normal samples from miscarriages and those from ongoing pregnancies (p = 0.3739). However, among the karyotypically abnormal samples, relative TLs were significantly higher in ongoing pregnancies than in miscarriages (p < 0.0001). Relative TLs were also significantly higher in chorion samples from karyotypically abnormal ongoing pregnancies than in those from karyotypically normal ones (p = 0.0018) in contrast to miscarriages, where relative TL values were higher in the karyotypically normal samples (p = 0.002). In the karyotypically abnormal chorionic cytotrophoblast, the TL variance was significantly lower than in any other group (p < 0.05). Assessed by TL ratios between sister chromatids, interchromatid TL asymmetry demonstrated similar patterns across all of the chorion samples (p = 0.22) but significantly exceeded that in PHA-stimulated lymphocytes (p < 0.0001, p = 0.0003). The longer telomere was predominantly present in the hydroxymethylated sister chromatid in chromosomes featuring hemihydroxymethylation (containing 5-hydroxymethylcytosine in only one sister chromatid)-a typical sign of chorionic cytotrophoblast cells. Our results suggest that the phenomena of interchromatid TL asymmetry and its association to 5hmC patterns in chorionic cytotrophoblast, which are potentially linked to telomere lengthening through recombination, are inherent to the development programme. The TL differences in chorionic cytotrophoblast that are associated with karyotype and embryo viability seem to be determined by heredity rather than telomere elongation mechanisms. The inheritance of long telomeres by a karyotypically abnormal embryo promotes his development, whereas TL in karyotypically normal first-trimester embryos does not seem to have a considerable impact on developmental capacity.

Association of Leukocyte Telomere Length and Genes Involved in its Regulation With Oral Carcinoma

BACKGROUND/AIM

This study aimed to determine the relationship between the relative leukocyte telomere length (RLTL) and gene polymorphisms involved in its regulation with the occurrence of oral squamous cell carcinoma (OSCC).

PATIENTS AND METHODS

Patients with OSCC and healthy subjects were examined. Genotyping and RLTL measurement were carried out using rPCR.

RESULTS

The OSCC group had longer telomeres than controls (p=0.001). Minor allele T at TERF1rs1545827 may increase RLTL shortening (p=0.047). TNKS2rs10509639 A/G and A/G+G/G genotypes were associated with a 2.6-fold increased odd (p=0.012) and a 2.4-fold increased odd (p=0.019) of RLTL elongation compared to A/A genotype. The A/G genotype was associated with a 2.6-fold increased odd (p=0.011) compared to the A/A+G/G genotypes. Each G allele was associated with a 2.1-fold increased odd of longer RLTL (p=0.036).

CONCLUSION

Longer telomeres were found in patients with OSCC than in controls. The TERF1 rs1545827 and the TNKS2 rs10509639 polymorphisms were associated with an increase in RLTL.

Correlation between Telomere Length and Chronic Obstructive Pulmonary Disease-Related Phenotypes: Results from the Chronic Obstructive Pulmonary Disease in Dusty Areas (CODA) Cohort

Background

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with increased prevalence in the elderly. Telomeres are repetitive DNA sequences found at the end of the chromosome, which progressively shorten as cells divide. Telomere length is known to be a molecular marker of aging. This study aimed to assess the relationship between telomere length and the risk of COPD, lung function, respiratory symptoms, and emphysema index in Chronic Obstructive Pulmonary Disease in Dusty Areas (CODA) cohort.

Methods

We extracted DNA from the peripheral blood samples of 446 participants, including 285 COPD patients and 161 control participants. We measured absolute telomere length using quantitative real-time polymerase chain reaction. All participants underwent spirometry and quantitative computed tomography scan. Questionnaires assessing respiratory symptoms and the COPD Assessment Test was filled by all the participants.

Results

The mean age of participants at the baseline visit was 72.5±7.1 years. Males accounted for 72% (321 participants) of the all participants. The mean telomere length was lower in the COPD group compared to the non-COPD group (COPD, 16.81±13.90 kb; non-COPD, 21.97±14.43 kb). In COPD patients, 112 (75.7%) were distributed as tertile 1 (shortest), 91 (61.1%) as tertile 2 and 82 (55%) as tertile 3 (longest). We did not find significant associations between telomere length and lung function, exacerbation, airway wall thickness, and emphysema index after adjusting for sex, age, and smoking status.

Conclusion

In this study, the relationship between various COPD phenotypes and telomere length was analyzed, but no significant statistical associations were shown.

Influence of Silica Exposure for Lung Silicosis Rat

OBJECTIVE

To investigate the influence of silica exposure on the expression of connective tissue growth factor (CTGF), transforming growth factor beta-1 (TGF-β1), and platelet-derived growth factor (PDGF) in lung silicosis rat.

METHODS

Wistar rats were divided into an experimental group and a control group. In the experimental group, rats were exposed to silica by intratracheal instillation. In the control group, rats were exposed to physiological saline by intratracheal instillation. After 45 days, we compared the level of fibrosis and CTGF, TGF-β1, and PDGF in the lungs by immunohistochemistry or reverse transcription-polymerase chain reaction between the two groups.

RESULTS

The results showed that the expression levels of CTGF, TGF-β1, and PDGF mRNA were significantly higher in the experimental group than those in the control group (P < 0.05). The positive staining of CTGF, TGF-β1, and PDGF mRNA was found in the cytoplasm, especially in the silicotic nodules of the hyalinisation section and cell endochylema of the alveolar macrophages, type II pneumonocytes, and lung tracheal epithelium. There were significantly positive correlations between CTGF, TGF-β1, and PDGF expressions (P < 0.05). A protein-protein interaction analysis showed interactions between TGF-β1, CTGF, and PDGF.

CONCLUSIONS

TGF-β/CTGF signaling pathway plays an important role in silicosis. Silicon dioxide exposure can induce the expression of CTGF, TGF-β1, and PDGF.

Investigations on the new mechanism of action for acetaldehyde-induced clastogenic effects in human lung fibroblasts

Acetaldehyde (AA) has been classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC, WHO) and by the US Environmental Protection Agency due to its ability to cause tumours following inhalation or alcohol consumption in animals. Humans are constantly exposed to AA through inhalation from the environment through cigarette smoke, vehicle fumes and industrial emissions as well as by persistent alcohol ingestion. Individuals with deficiencies in the enzymes that are involved in the metabolism of AA are more susceptible to its toxicity and constitute a vulnerable human population. Studies have shown that AA induces DNA damage and cytogenetic abnormalities. A study was undertaken to elucidate the clastogenic effects induced by AA and any preceding DNA damage that occurs in normal human lung fibroblasts as this will further validate the detrimental effects of inhalation exposure to AA. AA exposure induced DNA damage, involving DNA double strand breaks, which could possibly occur at the telomeric regions as well, resulting in a clastogenic effect and subsequent genomic instability, which contributed to the cell cycle arrest. The clastogenic effect induced by AA in human lung fibroblasts was evidenced by micronuclei induction and chromosomal aberrations, including those at the telomeric regions. Co-localisation between the DNA double strand breaks and telomeric regions was observed, suggesting possible induction of DNA double strand breaks due to AA exposure at the telomeric regions as a new mechanism beyond the clastogenic effect of AA. From the cell cycle profile following AA exposure, a G2/M phase arrest and a decrease in cell viability were also detected. Therefore, these effects due to AA exposure via inhalation may have implications in the development of carcinogenesis in humans.

Roles of telomeres and telomerase in age‑related renal diseases (Review)

Age‑related renal diseases, which account for various progressive renal disorders associated with cellular and organismal senescence, are becoming a substantial public health burden. However, their aetiologies are complicated and their pathogeneses remain poorly understood. Telomeres and telomerase are known to be essential for maintaining the integrity and stability of eukaryotic genomes and serve crucial roles in numerous related signalling pathways that activate renal functions, such as repair and regeneration. Previous studies have reported that telomere dysfunction served a role in various types of age‑related kidney disease through various different molecular pathways. The present review aimed to summarise the current knowledge of the association between telomeres and ageing‑related kidney diseases and explored the contribution of dysfunctional telomeres to these diseases. The findings may help to provide novel strategies for treating patients with renal disease.

Alterations in telomere length and mitochondrial DNA copy number in human lymphocytes on short-term exposure to moderate hypoxia

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Exposure to moderate hypoxia for 24 h significantly increased telomere length.

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Telomere elongation is related to the duration of hypoxia exposure.

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Mitochondrial DNA copy number was unaffected by hypoxia exposure.

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Mitochondrial DNA copy number is a more stable marker than telomere length alteration under hypoxia.

Hypoxia is related to a variety of diseases, such as cardiovascular and inflammatory diseases and various cancers. Telomere length (TL) may vary according to the hypoxia level and cell types. To the best of our knowledge, no study has investigated the effect of moderate hypoxia on TL and mitochondrial DNA copy number (mtDNAcn) in human lymphocytes. Therefore, in this study, we analyzed the effect of moderate hypoxia on TL in correlation with mtDNAcn. This study included 32 healthy male nonsmoker’s subjects; in this cohort, we had previously studied sister chromatid exchange and microsatellite instability. Blood samples from each subject were divided into three groups: a control group and two experimental groups exposed to moderate hypoxia for 12 or 24 h. Relative TL and mtDNAcn were measured by a quantitative real-time polymerase chain reaction. The TL in the control group did not significantly differ from that in the experimental group subjected to hypoxia for 12 h; however, the TL in the 24 h hypoxia–treated experimental group was significantly higher than that in the control group. The correlation between TL and mtDNAcn was not statistically significant in the two hypoxic states. The increase in TL was observed on exposure to hypoxia for 24 h and not for 12 h; thus, the findings suggest that telomere elongation is related to hypoxia exposure duration. The mtDNAcn in the two experimental groups did not significantly differ from that in the control group. These observations suggest that mtDNAcn alterations show more genetic stability than TL alterations. To the best of our knowledge, this is the first in vitro study on human lymphocytes reporting an increase in TL and no alteration in mtDNAcn after short-time exposure to moderate hypoxia.

Assessing the Relationship Between Leukocyte Telomere Length and Cancer Risk/Mortality in UK Biobank and TCGA Datasets With the Genetic Risk Score and Mendelian Randomization Approaches

Background

Telomere length is an important indicator of tumor progression and survival for cancer patients. Previous work investigated the associations between genetically predicted telomere length and cancers; however, the types of cancers investigated in those studies were relatively limited or the telomere length-associated genetic variants employed often came from genome-wide association studies (GWASs) with small sample sizes.

Methods

We constructed the genetic risk score (GRS) for leukocyte telomere length based on 17 associated genetic variants available from the largest telomere length GWAS up to 78,592 individuals. Then, a comprehensive analysis was undertaken to evaluate the association between the constructed GRS and the risk or mortality of a wide range of cancers [i.e., 37 cancers in the UK Biobank and 33 cancers in The Cancer Genome Atlas (TCGA)]. We further applied the two-sample Mendelian randomization (MR) to estimate the causal effect of leukocyte telomere length on UK Biobank cancers via summary statistics.

Results

In the UK Biobank dataset, we found that the GRS of leukocyte telomere length was associated with a decreased risk of nine types of cancer (i.e., significant association with multiple myeloma, chronic lymphocytic leukemia, kidney/renal cell cancer, bladder cancer, malignant melanoma, basal cell carcinoma, and prostate cancer and suggestive association with sarcoma/fibrosarcoma and Hodgkin’s lymphoma/Hodgkin’s disease). In addition, we found that the GRS was suggestively associated with an increased risk of leukemia. In the TCGA dataset, we observed suggestive evidence that the GRS was associated with a high death hazard of rectum adenocarcinoma (READ), sarcoma (SARC), and skin cutaneous melanoma (SKCM), while the GRS was associated with a low death hazard of kidney renal papillary cell carcinoma (KIRP). The results of MR further supported the association for leukocyte telomere length on the risk of malignant melanoma, Hodgkin’s lymphoma/Hodgkin’s disease, chronic lymphocytic leukemia and multiple myeloma.

Conclusion

Our study reveals that telomere played diverse roles in different types of cancers. However, further validations in large-scale prospective studies and deeper investigations of the biologic mechanisms are warranted.

Role of telomere shortening in anticipation of inflammatory bowel disease

BACKGROUND

The existence of genetic anticipation has been long disputed in inflammatory bowel disease (IBD) in the absence of the explanatory mechanism.

AIM

To determine whether it was predictive of genetic anticipation, we evaluated telomere length in IBD. We hypothesized that multiplex IBD families exhibit a genetic defect impacting telomere maintenance mechanisms.

METHODS

We studied three IBD families with multiple affected members in three successive generations. We determined telomere length (TL) in lymphocytes and granulocytes from peripheral blood of the affected members using flow cytometry and fluorescence in-situ hybridization (flow FISH). We also performed whole exome sequencing in the blood of all available family members and used PhenoDB to identify potential candidate gene variants with recessive or dominant modes of inheritance.

RESULTS

Out of twenty-four patients of European descent selected to participate in the study, eleven patients, eight parent-child pairs affected by IBD, were included in the genetic anticipation analysis. Median difference in age at diagnosis between two successive generations was 16.5 years, with earlier age at onset in the younger generations. In most of the affected members, the disease harbored similar gastrointestinal and extraintestinal involvement but was more aggressive among the younger generations. TL was not associated with earlier age at onset or more severe disease in members of successive generations affected by IBD. NOD2 gene mutations were present in the Crohn's disease patients of one family. However, no gene variants were identified as potential candidates for inheritance.

CONCLUSION

Telomere shortening appears unlikely to be involved in mechanisms of possible genetic anticipation in IBD. Further studies using a larger sample size are required to confirm or refute our findings.

Interaction effects of environmental response gene polymorphisms and benzene exposure on telomere length in shoe-making workers

Benzene is a globally occurring environmental and occupational pollutant that causes leukemia. To better understand telomere length (TL) as a function of benzene toxicity, we recruited 294 shoe-making workers and 102 controls from Wenzhou, China in 2011. Biomarkers of TL, cytokinesis-block micronucleus (MN) frequency, and white blood cells (WBC) were measured. In total, 18 polymorphic sites in environmental response genes, including metabolic and DNA repair genes, were analyzed. Results indicate that benzene exposure led to a longer TL at a threshold of 32 mg/m³-year of cumulative exposure dose (CED). Furthermore, the TL was longer in members of the damaged group, when evaluated for MN frequency (P < 0.001) and reduced WBC (P < 0.001), than in those of the normal group. Workers carrying genotype TT (β = 0.32, P = 0.042) in rs3212986 of ERCC1 and genotype TC (β = 0.24, P = 0.082) in rs1051740 of mEH exon3 were associated with a longer TL as compared to the wild-type group. TA (β = -0.53, P < 0.001) in rs6413432 of CYP2E1 was associated with a shorter TL. Benzene exposure interacted with the TA type in rs6413432 (β = 0.003, 95% CI: 0, 0.006, P = 0.042) and the CC type in rs1051740 (β = 0.007, 95% CI: 0.001, 0.013, P = 0.015) after adjusting for confounding factors. Our results indicate that benzene induces an increase in TL at a threshold of CED ≥32mg/m³-year. Rs1051740, rs3212986, and rs6413432 were found to be involved in benzene-induced telomere growth; in particular, rs1051740 and rs6413432 interacted with the benzene exposure, resulting in an extended TL.

Leukocyte Telomere Length and Its Interaction with Germline Variation in Telomere-Related Genes in Relation to Pancreatic Adenocarcinoma Risk

BACKGROUND

Leukocyte telomere length (LTL) has been associated with risk of multiple cancers, but its association with pancreatic ductal adenocarcinoma (PDAC) is unclear. We therefore investigated the association between peripheral blood LTL and PDAC risk, and examined effect modification by candidate SNPs previously reported to be associated with variation in LTL.

METHODS

A case-control study of 1,460 PDAC cases and 1,459 frequency-matched controls was performed using biospecimens and data from the Mayo Clinic Biospecimen Resource for Pancreas Research. Quantitative PCR was used to measure LTL and categorized into tertiles based on sex-specific control distribution. Eleven telomere-related SNPs also were genotyped. Logistic regression was used to calculate ORs and 95% confidence intervals (CI).

RESULTS

Shorter peripheral blood LTL was associated with a higher risk of PDAC (ORT1vsT3 = 1.26, 95% CI = 1.03-1.54, P trend = 0.02; ORcontinuous = 1.14, 95% CI = 1.02-1.28), but the association was restricted to cases with treatment-naïve blood samples (ORT1vsT3 = 1.51, 95% CI = 1.16-1.96, P trend = 0.002; ORcontinuous = 1.25, 95% CI = 1.08-1.45) and not cases whose blood samples were collected after initiation of cancer therapy (ORT1vsT3 = 1.10, 95% CI = 0.87-1.39, P trend = 0.42; ORcontinuous = 1.08, 95% CI = 0.94-1.23). Three SNPs (TERC-rs10936599, ACYP2-rs11125529, and TERC-rs1317082) were each associated with interindividual variation in LTL among controls, but there was no evidence of effect modification by these SNPs.

CONCLUSIONS

Treatment-naïve short LTL is associated with a higher risk of PDAC, and the association does not differ by germline variation in the candidate telomere-related SNPs examined.

IMPACT

Peripheral blood LTL might serve as a molecular marker for risk modeling to identify persons at high risk of PDAC.

Influence of metals from e-waste dismantling on telomerelength and mitochondrial DNA copy number in people living near recycling sites

Metals are the primary toxicants released by electronic waste (e-waste) recycling, but their adverse effects on people working in e-waste recycling or living near e-waste sites have not been studied well. Taizhou is one of the three largest e-waste recycling locations in China. Atpresent, to prevent the environmental problems stem from e-waste dismantling, the local government has shut down all the industries in 2015. In this study, we collected blood samples of residents living near e-waste dismantling factories, and in matched reference areas in Taizhou, in December 2017, after the factories have been shut down for two years. Seventeen metals were quantified in all blood samples. Among them, the concentrations of arsenic (As), nickel (Ni), silver (Ag), lanthanum (La), and Cerium (Ce) were statistically significant higher in individuals in e-waste recycling locations than those in reference location. Length of telomere (LOT) and mitochondrialDNA copy number (MCN) were measured in blood as a marker of human health. In the e-waste dismantling location, the level LOT and MCN were elevated in resident living near e-waste sites (RE) and former working in e-waste recycling (OE) than residents living in the reference area (RF). Furthermore, Pearson correlation and multiple linear regression analysis between the changed metals and LOT, MCN in blood were performed. In RE and OE, the concentration of Ni significantly positively correlated with MCN; in OE, the Ni level significantly positively correlated with MCN and LOT. Considering that the high level of Ni, TL and mtDNA were correlated with the risk of cancer, we speculated that e-waste exposure elevate the risk of cancer, and Ni that has long been present in the body was the potential hazardous element causing cancer.

Prognostic Value of Peripheral Blood Lymphocyte Telomere Length in Gynecologic Malignant Tumors

Background: Lymphocyte telomere length is strongly correlated with patient prognosis in several malignant tumor types and is thought to be related to tumor immunity. However, this correlation has not been studied in gynecological cancers. We determined the prognostic significance of peripheral blood lymphocyte telomere length in gynecologic cancers. Methods: Telomere length of lymphocytes from patients with gynecological malignant tumors (ovarian cancer (OC), N = 72; cervical cancer (CC), N = 63; endometrial cancer (EC), N = 87) was examined by quantitative reverse-transcription PCR of isolated mononuclear cells. Kaplan–Meier and Cox proportional hazard analyses were used to determine the association between lymphocyte telomere length and clinicopathological factors. Results: The overall survival (OS) and progression-free survival (PFS) of patients were based on the dichotomized lymphocyte telomere length using the median as a threshold (OC: 0.75, CC: 1.94, and EC: 1.09). A short telomere length was significantly correlated with residual tumors (≥1 cm) in OC and with advanced stage (III and IV) of CC. In OC and CC, patients with shorter relative lymphocyte telomere length (RLT) had significantly poorer OS and PFS than patients with longer RLT (p = 0.002, p = 0.003, and p = 0.001, p = 0.001, respectively). However, in EC, RLT was not significantly associated with OS or PFS (p = 0.567 and p = 0.304, log-rank test). Multivariate analysis showed that shorter RLT was a significant independent prognostic factor of PFS and OS for OC (p = 0.03 and p = 0.04, respectively) and CC (p = 0.02 and p = 0.03, respectively). Conclusions: Patients with OC and CC with shorter lymphocyte telomeres have significantly reduced survival; therefore, the peripheral blood lymphocyte telomere length is a prognostic biomarker in OC and CC.

Aberrant Telomere Length in Circulating Cell-Free DNA as Possible Blood Biomarker with High Diagnostic Performance in Endometrial Cancer

To investigate the diagnostic performance of relative telomere length (RTL) in cell-free DNA (cfDNA) for endometrioid endometrial cancer (EC). We measured RTL in cfDNA of 40 EC patients (65 ± 12 years) and 31 healthy controls (HC) (63 ± 13 years), excluding in both groups other oncologic and severe non-oncologic diseases to limit confounders. Circulating cfDNA was extracted from serum using the QIAamp DNA Blood Mini kit (Qiagen, Hilden, Germany). After the quantitative real-time polymerase chain reaction, telomere repeat copy number to single-gene copy number ratio was calculated. RTL in cfDNA was found to be significantly lower in EC patients than in HC (p < 0.0001). The diagnostic performance of cfDNA RTL was estimated with receiver operating characteristics (ROC) curve analysis, which showed a diagnostic accuracy for EC of 0.87 (95% CI: 0.79-0.95, p < 0.0001). The cutoff cfDNA RTL value of 2.505 (T/S copy ratio) reported a sensitivity of 80.0% (95% CI: 64.35-90.95) and a specificity of 80.65% (95% CI: 62.53-92.55). Significant differences of RTL among EC stages or grades (p = 0.85 and p = 0.89, respectively) were not observed. Our results suggest that cfDNA RTL analysis may be a diagnostic tool for EC detection since the early stage, whilst its diagnostic performance seems unsatisfactory for cancer progression, staging, and grading. However, further studies are needed to confirm these preliminary findings. In particular, future investigations should focus on high-risk patients (such as those with atypical endometrial hyperplasia) that may benefit from this tool, because TL shortening is not specific for EC and is influenced by other oncologic and non-oncologic diseases.

Leukocyte telomere length and hTERT genetic polymorphism rs2735940 influence the renal cell carcinoma clinical outcome

Aim: Analysis of the genetic hTERT-1327 C>T (rs2735940) influence on leukocyte telomere length (LTL) and tumor development, progression and overall survival in renal cell carcinoma (RCC) patients. Materials & methods: Using leukocyte DNA of RCC patients and healthy individuals, LTL measurement and allelic discrimination of rs2735940 was performed by real-time PCR. Results: RCC patients showed shorter LTL than healthy individuals and LTL increased with clinical stage. CC+TC genotypes healthy carriers' presented shorter LTL. However, no statistical association between the different genotypes and RCC risk. Nevertheless, CC homozygous presented a reduced time to disease progression and a lower overall survival. The use of hTERT-1327 single nucleotide polymorphism information increased the capacity to predict risk for RCC progression. Conclusion: In fact, in healthy individuals, hTERT-1327 CC+TC genotypes were associated with shorter LTL, and this single nucleotide polymorphism was associated with time to disease progression, being a promising potential prognosis biomarker to be used in the future.

Finding of novel telomeric repeats and their distribution in the human genome

Telomeres, the nucleoprotein structures, located at the end of the chromosomes are correlated with cancer and aging. The accelerated telomere attrition can accelerate human aging and leads to the progression of several cancers. Our work describes the finding of two novel telomeric repeats "CACAGA" and "TCTCTGCGCCTGCGCCGGCGCGGCGCGCC" and demonstrates their distribution in human chromosomes compare to the reported telomeric repeat TTAGGG. Simultaneously, the distance between the adjacent telomeric repeats (loop) was determined and the presence of shorter loops in the telomeric regions might address the correlation between the telomere attrition and senescence condition in human.

Long Leukocyte Telomere Length Is Associated with Increased Risks of Soft Tissue Sarcoma: A Mendelian Randomization Study

Background: Leukocyte telomere length (LTL) has been associated with the risks of several cancers in observational studies. Mendelian randomization (MR) studies, using genetic variants as instrumental variables, have also shown associations of genetically predicted LTL with cancer risks. In this study, we performed the first MR analysis on soft tissue sarcoma (STS) to investigate the causal relationship between LTL and the risk of STS. Methods: Genotypes from eleven LTL-associated single nucleotide polymorphisms (SNPs) in 821 STS cases and 851 cancer-free controls were aggregated into a weighted genetic risk score (GRS) to predict LTL. Multivariate logistic regression was used to assess the association of STS risk with individual SNPs and aggregated GRS. Results: Four SNPs displayed evidence for an individual association between long LTL-conferring allele and increased STS risk: rs7675998 (odds ratio (OR) = 1.21, 95% confidence interval (CI) = 1.02–1.43), rs9420907 (OR = 1.31, 95% CI = 1.08–1.59), rs8105767 (OR = 1.18, 95% CI = 1.02–1.37), and rs412658 (OR = 1.18, 95% CI = 1.02–1.36). Moreover, longer genetically predicted LTL, calculated as GRS, was strongly associated with an increased risk of STS (OR = 1.44, 95% CI = 1.18–1.75, p < 0.001), and there was a significant dose-response association (p for trend <0.001 in tertile and quartile analyses). The association of longer LTL with higher STS risk was more evident in women than in men. In stratified analyses by major STS subtypes, longer LTL was significantly associated with higher risks of leiomyosarcoma and gastrointestinal stromal tumors. Conclusions: Longer LTL is associated with increased risks of STS.

Leukocyte telomere length is associated with aggressive prostate cancer in localized prostate cancer patients

BACKGROUND

Telomeres play important roles in cancer initiation and progression. The aim of this study is to investigate whether leukocyte telomere length (LTL) is associated with aggressive prostate cancer (PCa).

METHODS

We measured relative LTL in a cohort of 1,889 white PCa patients who were treated and followed up at the University of Texas MD Anderson Cancer Center and assessed its associations with aggressive disease characteristics at diagnosis and biochemical recurrence (BCR) after active treatments (radical prostatectomy and radiotherapy). We further used a Mendelian randomization (MR) approach to compute a weighted genetic risk score (GRS) predictive of LTL using 10 established LTL-associated genetic variants and determined whether this GRS is associated with aggressive PCa.

FINDINGS

LTL was significantly shorter in patients with higher Gleason scores at diagnosis. Dichotomized at the median value of LTL, patients with short LTL exhibited a 2.74-fold (95% confidence interval, 1.79-4.18, P = 3.11 × 10^-6) increased risk of presenting with GS≥8 disease than those with long LTL in multivariate logistic regression analysis. Moreover, shorter LTL was significantly associated with an increased risk of BCR (hazard ratio = 1.53, 95% confidence interval, 1.01-2.34) compared to longer LTL in localized patients receiving prostatectomy or radiotherapy with a significant dose-response association (P for trend = 0.017) in multivariate Cox proportional hazards regression analysis. In MR analysis, genetically predicted short LTL was also associated with an increased risk of BCR (HR=1.73, 95% CI, 1.08-2.78).

INTERPRETATION

Our results showed for the first time that LTL was shorter in PCa patients with high Gleason scores and that short LTL and genetically predicted short LTL are associated with worse prognosis in PCa patients receiving prostatectomy or radiotherapy.

FUNDING

Cancer Prevention and Research Institute of Texas (CPRIT) grant (RP140556), National Cancer Institute Specialized Program of Research Excellence (SPORE) grant (CA140388), and MD Anderson Cancer Center start-up fund.

Lymphocyte telomere length predicts clinical outcomes of HPV-positive oropharyngeal cancer patients after definitive radiotherapy

Because lymphocyte telomere length (LTL) plays critical roles in the maintenance of genomic stability and integrity, LTL thus may influence the etiology and prognosis of squamous cell carcinoma of the oropharynx (SCCOP). However, given the association between LTL and risk of human papillomavirus (HPV)-associated SCCOP and between LTL and tumor HPV status of SCCOP, we hypothesized that LTL is associated with SCCOP prognosis, particularly in HPV-positive patients after definitive radiotherapy. LTL and tumor HPV type 16 (HPV16) status were determined in 564 incident SCCOP patients before radiotherapy or chemoradiation. Both univariate and multivariable Cox regression analyses were performed to estimate the association between LTL and prognosis. Eighty-five percent patients had HPV16-positive tumors. Patients with shorter telomeres had significantly better overall, disease-specific and disease-free survival than did those with longer telomeres (log-rank P < 0.001). Moreover, patients with shorter telomeres had significantly lower risk of death overall [hazard ratio (HR) = 0.2; 95% confidence interval (CI) = 0.1-0.4], death due to SCCOP (HR = 0.2; 95% CI = 0.1-0.4) and SCCOP recurrence (HR = 0.3; 95% CI = 0.2-0.5) after adjusting for other important prognostic confounders. Finally, we found more pronounced effects of LTL on survival in HPV16-positive SCCOP patients after stratified analysis according to tumor HPV status. These findings indicate that LTL plays a significant role in the survival of patients with SCCOP, especially HPV16-positive patients who undergo definitive radiotherapy. Therefore, pretreatment LTL may be an independent prognostic biomarker for HPV16-positive SCCOP. Prospective studies with larger sample sizes are needed to confirm these findings.

Telomere length in peripheral blood leukocytes and risk of renal cell carcinoma

BACKGROUND

Telomeres are essential for chromosomal stability and may play a key role in carcinogenesis. Telomere length is suggested as a tentative biomarker of risk for renal cell carcinoma (RCC). However, results of previous association studies between telomere length and risk for RCC are inconsistent.

METHODS

We evaluated RCC risk in relation to peripheral blood leukocyte telomere length using a hospital-based case-control study of 169 RCC cases and 189 controls. Cases were histologically-confirmed RCC patients who were treated at the Moffitt Cancer Center (Tampa, FL). Controls with no history of cancer underwent a screening exam at the Lifetime Cancer Screening Center at Moffitt Cancer Center to rule out the presence of cancer. Relative telomere length (RTL) was measured by quantitative real-time polymerase chain reaction (PCR) using peripheral blood leukocyte DNA. Logistic regression was used to determine the association between RTL and RCC risk.

RESULTS

As expected, increasing age was inversely correlated with RTL (Pearson r=-0.213, P=0.003) among controls but not cases. Average RTL was significantly shorter in cases as compared with controls [mean ± standard deviation (SD): 3.18±1.50 and 4.39±1.99, respectively, P<0.001]. In contrast, average RTL was not significantly different by gender, race, smoking status among controls or by clinical stages among RCC cases. In regression analysis, we observed that shorter RTL is significantly associated with RCC risk [odds ratio (OR) =1.48; 95% confidence interval (CI): 1.27-1.71] after adjustment for covariates.

CONCLUSIONS

We found that shorter RTL is associated with an increased risk for RCC. Our findings suggest that telomere length may be involved in the development of RCC.

Association of nutraceutical supplements with longer telomere length

Telomeres are nucleotide tandem repeats located at the tip of eukaryotic chromosomes that maintain genomic integrity. The gradual shortening of telomeres leads to cellular senescence and apoptosis, a key mechanism of aging and age‑related chronic diseases. Epigenetic factors, such as nutrition, exercise and tobacco can affect the rate at which telomeres shorten and can modify the risk of developing chronic diseases. In this study, we evaluated the effects of a combination of nutraceutical supplements (NS) on telomere length (TL) in healthy volunteers with no medical history of any disease. Participants (n=47) were selected from healthy outpatients visiting a private clinic and were divided into the experimental group (n=16), that received the NS and the control group (n=31). We estimated the length of single telomeres in metaphase spread leukocytes, isolated from peripheral blood, using quantitative‑fluorescent in situ hybridization (Q‑FISH) analysis. The length of the whole telomere genome was significantly increased (P<0.05) for the mean, 1st quartile and median measurements in the experimental group. Similar findings were observed for short TL (20th percentile) (P<0.05) for the median and 3rd quartile measurements in the NS group, compared to the control group. The beneficial effects of the supplements on the length of short telomeres remained significant (P<0.05) following adjustment for age and sex. Telomeres were moderately longer in female patients compared to the male patients. On the whole, the findings of this study suggest that the administration of NS may be linked to sustaining the TL.