Telomere Length Research Articles

Impact of childhood maltreatment on aging: a comprehensive Mendelian randomization analysis of multiple age-related biomarkers

BackgroundChildhood maltreatment (CM) is linked to long-term adverse health outcomes, including accelerated biological aging and cognitive decline. This study investigates the relationship between CM and various aging biomarkers: telomere length, facial aging, intrinsic epigenetic age acceleration (IEAA), GrimAge, HannumAge, PhenoAge, frailty index, and cognitive performance.MethodsWe conducted a Mendelian randomization (MR) study using published GWAS summary statistics. Aging biomarkers included telomere length (qPCR), facial aging (subjective evaluation), and epigenetic age markers (HannumAge, IEAA, GrimAge, PhenoAge). The frailty index was calculated from clinical assessments, and cognitive performance was evaluated with standardized tests. Analyses included Inverse-Variance Weighted (IVW), MR Egger, and Weighted Median (WM) methods, adjusted for multiple comparisons.ResultsCM was significantly associated with shorter telomere length (IVW: β = − 0.1, 95% CI − 0.18 to − 0.02, pFDR = 0.032) and increased HannumAge (IVW: β = 1.33, 95% CI 0.36 to 2.3, pFDR = 0.028), GrimAge (IVW: β = 1.19, 95% CI 0.19 to 2.2, pFDR = 0.040), and PhenoAge (IVW: β = 1.4, 95% CI 0.12 to 2.68, pFDR = 0.053). A significant association was also found with the frailty index (IVW: β = 0.31, 95% CI 0.13 to 0.49, pFDR = 0.006). No significant associations were found with facial aging, IEAA, or cognitive performance.ConclusionsCM is linked to accelerated biological aging, shown by shorter telomere length and increased epigenetic aging markers. CM was also associated with increased frailty, highlighting the need for early interventions to mitigate long-term effects. Further research should explore mechanisms and prevention strategies.

Aging, Cancer, and Inflammation: The Telomerase Connection.

Understanding the complex dynamics of telomere biology is important in the strong link between aging and cancer. Telomeres, the protective caps at the end of chromosomes, are central players in this connection. While their gradual shortening due to replication limits tumors expansion by triggering DNA repair mechanisms, it also promotes oncogenic changes within chromosomes, thus sustaining tumorigenesis. The enzyme telomerase, responsible for maintaining telomere length, emerges as a central player in this context. Its expression in cancer cells facilitates the preservation of telomeres, allowing them to circumvent the growth-limiting effects of short telomeres. Interestingly, the influence of telomerase extends beyond telomere maintenance, as evidenced by its involvement in promoting cell growth through alternative pathways. In this context, inflammation accelerates telomere shortening, resulting in telomere dysfunction, while telomere elements also play a role in modulating the inflammatory response. The recognition of this interplay has promoted the development of novel therapeutic approaches centered around telomerase inhibition. This review provides a comprehensive overview of the field, emphasizing recent progress in knowledge and the implications in understanding of cancer biology.

Overexpression of protection of telomeres 1 (POT1), a single-stranded DNA-binding proteins in alfalfa (Medicago sativa), enhances seed vigor

Extensive bodies of research are dedicated to the study of seed aging with a particular focus on the roles of reactive oxygen species (ROS), and the ensuing oxidative damage during storage, as a primary cause of seed vigor decreasing. ROS diffuse to the nucleus and damage the telomeres, resulting in a loss of genetic integrity. Protection of telomeres 1 (POT1) is a telomeric protein that binds to the telomere region, and plays an essential role in maintaining genomic stability in plants. In this study, there were totally four MsPOT1 genes obtained from alfalfa genome. Expression analysis of four MsPOT1 genes in germinated seed presented the different expressions. Four MsPOT1 genes displayed high expression levels at the early stage of seed germination, Among the four POT1 genes, it was found that MS. gene040108 was significantly up-regulated in the early germination stage of CK seeds, but down-regulated in aged seeds. RT-qPCR assays and RNA-seq data revealed that MsPOT1-X gene was significantly induced by seed aging treatment. Transgenic seeds overexpressing MsPOT1-X gene in Arabidopsis thaliana and Medicago trunctula exhibited enhanced seed vigor, telomere length, telomerase activity associated with reduced H2O2 content. These results would provide a new way to understand aging stress-responsive MsPOT1 genes for genetic improvement of seed vigor. Although a key gene regulating seed vigor was identified in this study, the specific mechanism of MsPOT1-X gene regulating seed vigor needs to be further explored.

B Cells Isolated from Individuals Who Do Not Respond to the HBV Vaccine Are Characterized by Higher DNA Methylation-Estimated Aging Compared to Responders.

Healthcare workers (HCWs) are a high-risk group for hepatitis B virus (HBV) infection. Notably, about 5-10% of the general population does not respond to the HBV vaccination. In this study, we aimed to investigate DNA methylation (DNAm) in order to estimate the biological age of B cells from HCW of both sexes, either responder (R) or non-responder (NR), to HBV vaccination. We used genome-wide DNA methylation data to calculate a set of biomarkers in B cells collected from 41 Rs and 30 NRs between 22 and 62 years old. Unresponsiveness to HBV vaccination was associated with accelerated epigenetic aging (DNAmAge, AltumAge, DunedinPoAm) and was accompanied by epigenetic drift. Female non-responders had higher estimates of telomere length and lower CRP inflammation risk score when compared to responders. Overall, epigenetic differences between responders and non-responders were more evident in females than males. In this study we demonstrated that several methylation DNAm-based clocks and biomarkers are associated with an increased risk of non-response to HBV vaccination, particularly in females. Based on these results, we propose that accelerated epigenetic age could contribute to vaccine unresponsiveness. These insights may help improve the evaluation of the effectiveness of vaccination strategies, especially among HCWs and vulnerable patients.

The association between telomere length and diabetes mellitus: accumulated evidence from observational studies.

In order to assess the associations between telomere length (TL) and diabetes mellitus (DM), especially type 2 diabetes (T2DM), we performed this systematic review and meta-analysis. PubMed, Embase, and Web of Science were thoroughly searched up to July 11, 2023. The pooled standardized mean difference (SMD) and the 95% confidence interval (CI) were evaluated using the random-effects model. Age, sex, study design, duration of diabetes, region, sample size, and body mass index (BMI) were used to stratify subgroup analyses. A total of 37 observational studies involving 18,181 participants from 14 countries were included in the quantitative meta-analysis. In this study, patients with diabetes had shorter TL than the non-diabetic, whether those patients had T1DM (-2.70; 95% CI: -4.47, -0.93; P<0.001), T2DM (-3.70; 95% CI: -4.20, -3.20; P<0.001), or other types of diabetes (-0.71; 95% CI: -1.10, -0.31; P<0.001). Additionally, subgroup analysis of T2DM showed that TL was significantly correlated with age, sex, study design, diabetes duration, sample size, detection method, region, and BMI. A negative correlation was observed between TL and DM. To validate this association in the interim, more extensive, superior prospective investigations and clinical trials are required.

Mixture analysis of associations between environmental and workplace toxins and liver damage and telomere length, stratified by race/ethnicity

This study aimed to identify the worst “bad actors” in mixtures of pollutants contributing to liver damage and shorter telomeres in the U.S. population, using Weighted Quantile Sum (WQS) modeling with stratification by race/ethnicity. We conducted a comprehensive cross-sectional analysis of mixtures of pollutants in National Health and Nutrition Examination Survey datasets: a) 33,979 adults with blood levels of cadmium (Cd), lead (Pb), and mercury, including subsets with measurements of per-/polyfluoroalkyl substances (PFAS), and polychlorinated biphenyls (PCBs)/polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs); and b) 7360 adults with measurements of telomeres, Cd, and Pb. Multivariable-adjusted WQS regression examined associations between WQS mixture indices and liver injury [alanine aminotransferase (ALT)-elevation], advanced liver-fibrosis (LF), and telomere length. WQSmetal indices were associated with advanced-LF in all racial/ethnic groups. The top contributor was Cd in the total population and in non-Hispanic Whites (NHW), while Pb was the top contributor in non-Hispanic Blacks (NHB). The WQSmetal-PCB-PCDD/F index was associated with ALT-elevation, with PCB126, Cd and Pb as main contributors; the odds ratio (OR) per decile was 1.50 (95%CI, 1.26-1.78), while the OR per decile of the WQSmetal-PFAS index was 1.03 (95%CI, 0.98-1.05), not significant. WQSmetal indices were associated with shorter telomeres. Cd was main contributor associated with advanced-LF in NHW, while Pb was the major bad actor in NHB, suggesting that NHB may be especially susceptible to Pb toxicity. Metals were associated with shorter telomeres. Metal and PCB/PCDD/F mixtures were associated with ALT-elevation. Heavy metals and organic chemicals may contribute to liver-related morbidity and healthcare disparities.

Dynamics of Leukocyte Telomere Length in Patients with Fabry Disease.

Fabry disease (FD) leads to significant morbidity and mortality, which may indicate accelerated ageing. However, it is still unclear whether there is a relationship between telomere length (TL), a marker of biological ageing, and disease outcome. We aimed to examine the relationship between leukocyte TL (LTL) dynamics and the presence of advanced disease stages and/or late complications of FD, including hypertrophic cardiomyopathy, nephropathy and stroke, both cross-sectionally and longitudinally. DNA was extracted from peripheral blood leukocytes and quantitative PCR was utilized to determine relative LTL in 99 Fabry patients. In the longitudinal analysis, we included 50 patients in whom at least three measurements were performed over a period of 5-10 years. The results showed a significant inverse correlation between LTL and age (ρ = -0.20, p = 0.05). No significant differences in LTL were found between females and males (p = 0.79) or between patients receiving disease-specific therapy and those without (p = 0.34). In a cross-sectional analysis, no association was found between the presence (p = 0.15) or number (p = 0.28) of advanced stages of the disease and/or late complications and LTL. Similarly, in a longitudinal analysis, no difference in LTL dynamics was found regarding the presence (p = 0.16) of advanced stage organ involvement and/or late complications or their number. These findings indicate that LTL dynamics in adulthood may not be a reliable indicator of disease outcomes in Fabry patients. Therefore, LTL may more accurately reflect the disease burden in early life, when TL is primarily determined.

High prevalence of short telomeres in idiopathic porto-sinusoidal vascular disorder.

Telomeres prevent damage to coding DNA as end-nucleotides are lost during mitosis. Mutations in telomere maintenance genes cause excessive telomere shortening, a condition known as short telomere syndrome (STS). One hepatic manifestation documented in STS is porto-sinusoidal vascular disorder (PSVD). As the etiology of many cases of PSVD remains unknown, this study explored the extent to which short telomeres are present in patients with idiopathic PSVD. This monocentric cross-sectional study included patients with histologically defined idiopathic PSVD. Telomere length in 6 peripheral blood leukocyte subpopulations was assessed using fluorescent in situ hybridization and flow cytometry. Variants of telomere-related genes were identified using high-throughput exome sequencing. In total, 22 patients were included, of whom 16 (73%) had short (9/22) or very short (7/22) telomeres according to age-adjusted reference ranges. Fourteen patients (64%) had clinically significant portal hypertension. Shorter telomeres were more frequent in males (p = 0.005) and patients with concomitant interstitial lung disease (p < 0.001), chronic kidney disease (p < 0.001), and erythrocyte macrocytosis (p = 0.007). Portal hypertension (p = 0.021), low serum albumin level (p < 0.001), low platelet count (p = 0.007), and hyperbilirubinemia (p = 0.053) were also associated with shorter telomeres. Variants in known STS-related genes were identified in 4 patients with VSTel and 1 with STel. Short and very short telomeres were highly prevalent in patients with idiopathic PSVD, with 31% presenting with variants in telomere-related genes. Telomere biology may play an important role in vascular liver disease development. Clinicians should consider measuring telomeres in any patient presenting with PSVD.

Comprehensive Analysis of a Japanese Pedigree with Biallelic ACAGG Expansions in RFC1 Manifesting Motor Neuronopathy with Painful Muscle Cramps.

Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is an autosomal recessive multisystem neurologic disorder caused by biallelic intronic repeats in RFC1. Although the phenotype of CANVAS has been expanding via diagnostic case accumulation, there are scant pedigree analyses to reveal disease penetrance, intergenerational fluctuations in repeat length, or clinical phenomena (including heterozygous carriers). We identified biallelic RFC1 ACAGG expansions of 1000 ~ repeats in three affected siblings having sensorimotor neuronopathy with spinocerebellar atrophy initially presenting with painful muscle cramps and paroxysmal dry cough. They exhibit almost homogeneous clinical and histopathological features, indicating motor neuronopathy. Over 10years of follow-up, painful intractable muscle cramps ascended from legs to trunks and hands, followed by amyotrophy and subsequent leg pyramidal signs. The disease course combined with the electrophysical and imagery data suggest initial and prolonged hyperexcitability and the ensuing spinal motor neuron loss, which may progress from the lumbar to the rostral anterior horns and later expand to the corticospinal tract. Genetically, heterozygous ACAGG expansions of similar length were transmitted in unaffected family members of three successive generations, and some of them experienced muscle cramps. Leukocyte telomere length assays revealed comparatively shorter telomeres in affected individuals. This comprehensive pedigree analysis demonstrated a non-anticipating ACAGG transmission and high penetrance of manifestations with a biallelic state, especially motor neuronopathy in which muscle cramps serve as a prodromal and disease progress marker. CANVAS and RFC1 spectrum disorder should be considered when diagnosing lower dominant motor neuron disease, idiopathic muscle cramps, or neuromuscular hyperexcitability syndromes.

Does BioAge identify accelerated aging in individuals with bipolar disorder? An exploratory study in the FACE-BD cohort.

Individuals with bipolar disorders (BD) have an estimated loss of life expectancy around 10-15 years. Several laboratory-measured biomarkers of accelerated aging exist (e.g., telomere length), however with a questionable transferability to bedside. There is a need for easily and inexpensively measurable markers of aging, usable in routine practice, such as BioAge. We calculated BioAge that estimates biological age based on routine blood tests and a physical exam, in a sample of 2220 outpatients with BD. We investigated associations between BioAge Acceleration (BioAgeAccel), which is an indicator of accelerated aging, and sociodemographic variables, clinical variables, and current psychotropic medication use. Mean chronological age was 40.2 (±12.9). Mean BioAge was 39.1 (±12.4). Mean BioAgeAccel was 0.08 (±1.8). A minority of individuals (15%) had a BioAgeAccel above 2 years. Multivariable analyses suggested strong associations between a higher BioAgeAccel and younger age, male sex, overweight and sleep disturbances. Regarding current psychotropic medication use, discrepancies between univariate and multivariate analyses were observed. A minority of individuals with BD had an accelerated aging as measured by BioAge. We identified associations with potentially modifiable factors, such as higher body mass index and sleep disturbances, that are however nonspecific to BD. These results require replications in independent samples of individuals with BD, and comparisons with a control group matched for age and gender. Longitudinal studies are also required to test whether any change in metabolic health, or sleep might decrease BioAgeAccel.

Investigating the differential therapeutic efficacy and mechanisms of human umbilical cord mesenchymal stem cells at various passages in osteoarthritis treatment

This study aimed to assess the clinical efficacy of umbilical cord mesenchymal stem cells (hUC-MSCs) from different passages (P3, P8, and P13) in the treatment of knee osteoarthritis (OA) and explore the underlying mechanisms. The hUC-MSCs from each passage were characterized and evaluated for their stemness, migration, proliferation, and marker expression. Rats with OA were treated with hUC-MSCs from each passage, and the therapeutic effects were assessed based on knee swelling, discomfort, and pathological examination of the knee joint. Co-culture experiments were conducted to examine the ability of hUC-MSCs to stimulate type II collagen synthesis and inhibit MMP13 expression in chondrocytes. Telomere length and telomerase activity of hUC-MSCs from each passage were measured to investigate the reasons for the observed differences in clinical efficacy. The results revealed that P3 and P8 hUC-MSCs exhibited superior osteogenic and chondrogenic differentiation potential compared to P13, while P13 demonstrated stronger adipogenic differentiation. The wound healing rate was significantly higher in the P3 and P8 groups compared to P13. All hUC-MSC groups expressed high levels of CD90 and CD105, indicating their mesenchymal stem cell characteristics, while CD31 and CD45 were not expressed. CD105 expression was significantly reduced in the P13 group. In the treatment of rat osteoarthritis, there were no significant differences in knee swelling, discomfort, Mankin scores, and pathological findings between P3 and P8 hUC-MSC treatments. However, there was a significant difference between the 8th and 13th passages. Co-culture experiments showed that hUC-MSCs from P3 and P8 enhanced type II collagen synthesis and reduced MMP13 expression in chondrocytes. Although no significant difference was observed between the P3 and P8 groups, a significant difference was found between the P13 and P8 groups. Telomere length analysis revealed that P13 samples had significantly shorter telomeres compared to both P3 and P8. The telomerase activity was positive in P3 and P8 hUC-MSCs, indicating no significant difference between these passages, while it was negative in P13 hUC-MSCs. In conclusion, P3 and P8 hUC-MSCs exhibited superior therapeutic potential for knee osteoarthritis compared to P13, possibly due to their enhanced differentiation capacity and telomerase activity.

Clinical utility of relative telomere length analysis in pediatric bone marrow failure

IntroductionTelomere length related studies are limited in pediatric marrow failure cases due to difficulty in establishing population specific age related normograms. Moreover, there is paucity of data related to clinical relevance of telomere length in idiopathic aplastic anemia (IAA) and non telomere biology inherited bone marrow failure syndrome (IBMFS) cases. Methodology: Hence, in current study we investigated Relative telomere length (RTL) by RQ-PCR in 83 samples as: healthy controls (n = 44), IAA (n = 15) and IBMFS (n = 24). In addition, we performed chromosomal breakage studies and targeted NGS to screen for pathogenic variants. Results & Conclusion: Median RTL was significantly different between control vs. IBMFS (p-0.002), IAA vs. IBMFS (p-0.0075) and DC vs. non-DC IBMFS (p-0.011) but not between control vs. IAA (p-0.46). RTL analysis had clinical utility in differentiating BMF cases as 75 % (9/12) of DC had short/very short telomeres compared to only 17 % (2/12) of non-DC IBMFS, 7 % (1/15) of IAA and 7 % (3/44) of controls (p < 0.001).

Associations of childhood and adulthood body size, and child-to-adult body size change with adult telomere length.

To comprehensivelyexamine the associations of childhood and adulthood body size, and child-to-adult body size change with adult leucocyte telomere length (LTL). We included 453 602 participants from the UK Biobank. Childhood body size at the age of 10 years was collected through a questionnaire. Adulthood body size was assessed using body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fat mass index (FMI), and fat-free mass index (FFMI). Individuals with plumper body size in childhood exhibited shorter LTL in adulthood (-0.0086 [-0.0017, -0.0004]). Adulthood BMI (-0.0286 [-0.0315, -0.0258]), WC (-0.0271 [-0.0303, -0.0238]), WHR (-0.0269 [-0.0308, -0.0230]) and FMI (-0.0396 [-0.0438, -0.0351]) were negatively associated with LTL, whereas FFMI (0.0095 [0.0039, 0.0152]) was positively associated with LTL. Compared to individuals consistently having an average/normal weight in both childhood and adulthood, those who maintained or developed overweight/obesity from childhood to adulthood had a shorter adult LTL, regardless of childhood body size. Notably, the LTL shortening effect was not observed in individuals with plumper body size in childhood but normal weight in adulthood. Childhood and adulthood obesity are both associated with LTL shortening in adulthood. Transitioning to or maintaining overweight/obese status from childhood to adulthood is associated with shorter adult LTL, whereas this effect can be reversed if plumper children become normal weight.

Maternal smoking during pregnancy could accelerate aging in the adulthood: evidence from a perspective study in UK Biobank

BackgroundMaternal smoking during pregnancy (MSDP) is significantly linked to the short- or long-term health of offspring. However, little research has examined whether MSDP affect the aging rate of offspring. MethodsThis study used questionnaires to determine out whether the participants' mothers smoked when they were pregnant. For evaluating aging rate, we used the following several outcome measures: telomere length, frailty index, cognitive function, homeostatic dysregulation score, KDM-age, age-related hospitalization rate, premature death, and life expectancy. ResultAfter adjusting for covariates, we found that the offspring of the MSDP group had significantly shorter telomere length in adulthood by 0.8 % (β = −0.008,95%CI:−0.009 to −0.006) compared with non-MSDP group. Compared to the non-MSDP group, participants in MSDP group showed higher levels of homeostatic dysregulation (β = 0.015,95%CI: 0.007–0.024) and were frailer (β = 0.008,95%CI:0.007–0.009). The KDM age increased by 0.100 due to MSDP (β = 0.100,95 % CI:0.018–0.181), and the age acceleration of KDM algorithm also increases significantly (β = 0.101, 95%CI:0.020–0.183). Additionally, we found that the risk of aging-related hospitalizations was significantly higher than the non-MSDP group by 10.4 %(HR = 1.104,95%CI:1.066–1.144). Moreover, MSDP group had a 12.2 % increased risk of all-cause premature mortality (HR = 1.122,95%CI:1.064–1.182) and a significant risk of lung cancer-specific premature mortality increased by 55.4 %(HR = 1.554,95%CI:1.346–1.793). In addition, participants in the MSDP group had significantly decreased cognitive function and shorter life expectancies than those in non-MSDP group. ConclusionOur findings indicated a significant association between MSPD and accelerated aging, elevated hospitalization rates, increased premature mortality rates, and reduced life expectancies in offspring.

Function of telomeres in aging and anti-aging

Telomeres play a important role in the aging process. Telomeres normally shorten would lead to cellular senescence and the decline of various bodily functions in human. Application of interventions could reduce the rate of aging. In this review paper, we hope to the find ways in preserving telomere length and function roles of telomeres in aging and anti-aging programs.

Influence of Parents Socioeconomic Status on Newborn Telomere Length

Background: Telomeres, the marker of biological aging, are substantially influenced by parental untoward exposures and their socioeconomic status (SES). This study aimed to find the association between parents–newborn leukocyte telomere length (LTL) among different SES highlighting reprogramming during fetal life. Methods: The parents' and newborn blood samples (n = 612, 204 each) were collected from September 2021 and July 2022, from Ziauddin Hospitals, Karachi. The real time PCR was used to quantify telomere length (T/S ratio). IBM statistical package for the social sciences (SPSS) was used to carry out analyses and graphs were formed by using GraphPad prism. A P-value of &lt;0.05 was considered statistically significant. Results: The mean age of mothers range between 25-35 (27.5%) and fathers &lt;25 years (55.9). The mothers and their newborns in the upper middle SES had significantly longer LTL (2.7±1.30, 2.14±1.39, p&lt;0.001). Whereas low SES group showed insignificant difference between (Newborn vs. mother). Among father newborns upper middle and high SES groups showed significant differences in TL (p=0.001). Longer TL was seen in father-newborn of the upper middle group (2.69+1.37; 2.79+1.30) with significant difference (p=0.001). Conclusion: Newborns had longer TL compared to their parents, highlighting the in-utero reprogramming in all socioeconomic groups. These findings show the importance of risk factors and their comprehensive understanding and their significance in contributions during vital beginning period of newborns' TL.

Integration of multi-modal datasets to estimate human aging

Aging involves complex biological processes leading to the decline of living organisms. As population lifespan increases worldwide, the importance of identifying factors underlying healthy aging has become critical. Integration of multi-modal datasets is a powerful approach for the analysis of complex biological systems, with the potential to uncover novel aging biomarkers. In this study, we leveraged publicly available epigenomic, transcriptomic and telomere length data along with histological images from the Genotype-Tissue Expression project to build tissue-specific regression models for age prediction. Using data from two tissues, lung and ovary, we aimed to compare model performance across data modalities, as well as to assess the improvement resulting from integrating multiple data types. Our results demostrate that methylation outperformed the other data modalities, with a mean absolute error of 3.36 and 4.36 in the test sets for lung and ovary, respectively. These models achieved lower error rates when compared with established state-of-the-art tissue-agnostic methylation models, emphasizing the importance of a tissue-specific approach. Additionally, this work has shown how the application of Hierarchical Image Pyramid Transformers for feature extraction significantly enhances age modeling using histological images. Finally, we evaluated the benefits of integrating multiple data modalities into a single model. Combining methylation data with other data modalities only marginally improved performance likely due to the limited number of available samples. Combining gene expression with histological features yielded more accurate age predictions compared with the individual performance of these data types. Given these results, this study shows how machine learning applications can be extended to/in multi-modal aging research. Code used is available at https://github.com/zroger49/multi_modal_age_prediction.

Exposure to four typical heavy metals induced telomere shortening of peripheral blood mononuclear cells in relevant with declined urinary aMT6s in rats

Environmental heavy metals pollution have seriously threatened the health of human beings. An increasing number of researches have demonstrated that environmental heavy metals can influence the telomere length of Peripheral Blood Mononuclear Cells (PBMCs), which implicate biological aging as well as predicts diseases. Our previous study has shown that methylmercury (MeHg)-induced telomere shortening in rat brain tissue was associated with urinary melatonin metabolite 6-sulfatoxymelatonin (aMT6s) levels. Here, we aimed to further elucidate the impact of 4 typical heavy metals (As, Hg, Cd and Pb) on telomere length of PBMCs and their association with urinary aMT6s in rats. In this study, eighty-eight male Sprague-Dawley rats were randomized grouped into eleven groups. Among them, forty 3-month-old (young) and forty 12-month-old (middle-aged) rats were divided into young or middle-aged control groups as well as typical heavy metals exposed groups, respectively. Eight 24-month-old rats (old) was divided into aging control group. The results showed that MeHg exposure in young rats while sodium arsenite (iAs), MeHg, cadmium chloride (CdCl2), lead acetate (PbAc) exposure in middle-aged rats for 3 months significantly reduced the levels of and urinary aMT6s, as well as telomere length of PBMCs. In addition, they also induced abnormalities in serum oxidative stress (SOD, MDA and GPx) and inflammatory (IL-1β, IL-6 and TNF-α) indicators. Notably, there was a significant positive correlation between declined level of urinary aMT6s and the shortening of telomere length in PBMCs in rats exposed to 4 typical heavy metals. These results suggested that 4 typical heavy metals exposure could accelerate the reduction of telomere length of PBMCs partially by inducing oxidative stress and inflammatory in rats, while ageing may be an important synergistic factor. Urinary aMT6s detection may be a alternative method to reflect telomere toxic effects induced by heavy metal exposure.

Telomere Length, Telomerase Activity, and Vaginal Microbiome in Patients with HPV-Related Precancerous Lesions.

Persistent high-risk human papillomaviruses (HR HPVs) infection leads to the development of squamous intraepithelial lesions in cervical cells that may lead to cancer. The telomere length, telomerase activity, and species composition of the vaginal microbiome may influence the dynamic of changes and the process of carcinogenesis. In the present study, we analyze relative telomere length (RTL), relative hTERT expression (gene for the telomerase component-reverse transcriptase) in cervical smear cells and vaginal microbiomes. Total RNA and DNA were isolated from tissue samples of 109 patients from the following groups: control, carrier, low-grade or high-grade squamous intraepithelial lesion (L SIL and H SIL, respectively), and cancer. The quantitative PCR method was used to measure telomere length and telomerase expression. Vaginal microbiome bacteria were divided into community state types using morphotype criteria. Significant differences between histopathology groups were confirmed for both relative telomere length and relative hTERT expression (p < 0.001 and p = 0.001, respectively). A significant difference in RTL was identified between carriers and H SIL (p adj < 0.001) groups, as well as between carriers and L SIL groups (p adj = 0.048). In both cases, RTL was lower among carriers. The highest relative hTERT expression level was recorded in the H SIL group, and the highest relative hTERT expression level was recorded between carriers and the H SIL group (p adj < 0.001). A correlation between genotype and biocenosis was identified for genotype 16+A (p < 0.001). The results suggest that identification of HPV infection, telomere length assessment, and hTERT expression measurement together may be more predictive than each of these analyses performed separately.

5-aza-2′-deoxycytidine induces telomere dysfunction in breast cancer cells

AimsAzacitidine, a drug that epigenetically modifies DNA, is widely used to treat haematological malignancies. However, at low doses, it demethylates DNA, and as a result, can alter gene expression. In our previous publication, we showed that low doses of azacitidine induce telomere length elongation in breast cancer cells. In this study, we aim to identify the mechanisms which lead to telomere length increases. MethodsBreast cancer cell lines representing different molecular sub-types were exposed to 5-aza-2′-deoxycytidine (5-aza) in 2 and 3D cultures, followed by DNA, RNA, and protein extractions. Samples were then analysed for telomere length, DNA damage, telomerase, and ALT activity. ResultsWe show that treatment of the cell lines with 5-aza for 72 h induced DNA damage at the telomeres and increased ALT activity 3-fold. We also identified a gene, POLD3, which may be involved in the ALT activity seen after treatment. ConclusionOur results indicate that while 5-aza is a useful drug for treating haematological cancers, surviving cancer cells that have been exposed to lower doses of the drug may activate mechanisms such as ALT. This could lead to cancer cell survival and possible resistance to 5-aza clinically.