Telomere Length Research Articles

Exploring DNA methylation, telomere length, mitochondrial DNA, and immune function in patients with Long-COVID

BackgroundLong-COVID is defined as the persistency or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation. Common persistent symptoms are fatigue, sleep disturbances, post-exertional malaise (PEM), pain, and cognitive problems. Long-COVID is estimated to be present in about 65 million people. We aimed to explore clinical and biological factors that might contribute to Long-COVID.MethodsProspective longitudinal cohort study including patients infected with SARS-CoV-2 between March 2020 and March 2022. Patients were assessed between 4 and 12 months after infection at the COVID follow-up clinic at UZ Leuven. We performed a comprehensive clinical assessment (including questionnaires and the 6-min walking test) and biological measures (global DNA methylation, telomere length, mitochondrial DNA copy number, inflammatory cytokines, and serological markers such as C-reactive protein, D-dimer, troponin T).ResultsOf the 358 participants, 328 were hospitalised, of which 130 had severe symptoms requiring intensive care admission; 30 patients were ambulatory referrals. Based on their clinical presentation, we could identify 6 main clusters. One-hundred and twenty-seven patients (35.4%) belonged to at least one cluster. The bigger cluster included PEM, fatigue, sleep disturbances, and pain (n = 57). Troponin T and telomere shortening were the two main markers predicting Long-COVID and PEM-fatigue symptoms.ConclusionsLong-COVID is not just one entity. Different clinical presentations can be identified. Cardiac involvement (as measured by troponin T levels) and telomere shortening might be a relevant risk factor for developing PEM-fatigue symptoms and deserve further exploring.

Telomere Length Is Associated With Adverse Atrial Remodeling in Patients With Atrial Fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia with a massive burden on global health. The prevalence of AF increases dramatically with age and can be up to 18% in patients older than 80 years. Telomeres, which are short, repeated DNA sequences at the end of chromosomes, are known to act as a biological aging marker. In this study, we investigated the relation of telomere shortening and AF in the context of atrial remodeling. Furthermore, we assessed changes in the gene expression profiles of patients with AF according to telomere length (TL) and left atrial fibrosis. We included 72 patients undergoing catheter ablation for AF. Bipolar voltage maps were obtained to determine left atrial low voltage areas as a surrogate for atrial fibrosis. TL was quantified and correlated to low voltage areas. 3' mRNA sequencing was performed for gene expression profiling. Clonal hematopoiesis of indeterminate potential was assessed by next generation sequencing. Telomerase reverse transcriptase knockout (Tert-/-) and telomerase RNA component knockout (Terc-/-) mice were used to investigate the mechanistic impact of telomere shortening on atrial remodeling. Patients with advanced left atrial fibrosis had shorter telomeres compared with patients with healthy left atria. Furthermore, there was a strong correlation between the extent of left atrial low voltage areas, TL, and outcome after catheter ablation of AF. 24 months after ablation, only 26.5% of patients with advanced fibrosis and short TL were in sinus rhythm compared with 62.5% of patients with no/low fibrosis and long TL. Gene expression profiles and clonal hematopoiesis of indeterminate potential frequency differed in patients with AF with short and long telomeres. Finally, atrial tissue of mouse models with shortened telomeres showed marked left atrial fibrosis and over-expression of fibrosis-related genes. Telomere shortening is correlated with left atrial remodeling. Shorter telomeres are associated with a series of molecular events which could eventually lead to cardiac fibrosis and perpetuate AF.

The telomere connection between aging and cancer: The burden of replication stress and dysfunction.

Aging is a complex process that affects individuals at the molecular, cellular, tissue, and systemic levels, arising from the cumulative effects of damage and diminished repair mechanisms. This process leads to the onset of age-related diseases, including cancer, which exhibits increased incidence with age. Telomeres, the protective caps at chromosome ends, play a crucial role in genome stability and are closely connected with aging and age-related disorders. Both excessively short and long telomere lengths may contribute to cancer development when their balance is disrupted. Fragile telomeres, characterized by abnormalities and replication stress, may provide novel insights into the connection between aging and cancer. The accumulation of fragile telomeres, possibly due to intense replicative stress, may represent a key factor. Given the dynamic nature of telomeres, large longitudinal studies are essential for understanding their role in aging and cancer susceptibility, which is crucial for developing effective strategies to promote healthy aging and mitigate cancer risk.

Increased muscle satellite cell content and preserved telomere length in response to combined exercise training in patients with FSHD.

Facioscapulohumeral muscular dystrophy (FSHD) is an inherited muscle disease characterized by weakness and muscle wasting. In the absence of available treatments, exercise training has emerged as a potential strategy to attenuate muscle tissue deterioration. However, little is known about the impact of chronic exercise on degenerative events and regenerative capacity in FSHD muscle. Muscle biopsies were obtained from 16 FSHD patients before and after a 24week training program combining aerobic-, strength- and high-intensity exercise (Control; n = 8, Training; n = 8). Histochemical and immunohistochemical approaches were applied to assess histopathological signs, markers of regeneration, inflammatory infiltrates and satellite cell content. Muscle telomere length was measured as an indicator of the remaining regenerative capacity. The proportion of muscle fibres expressing developmental myosins and centralized myonuclei was not exacerbated after the intervention. Similarly, no alterations were observed in the number of inflammatory infiltrates (CD68+ cells). Alongside muscle hypertrophy in slow (P=0.022) and fast fibres (P=0.022 and P=0.008), satellite cell content increased specifically in fast fibres (+75 %, P=0.015), indicating a functional satellite cell pool in FSHD muscle. Importantly, exercise training was not associated with a shortening of muscle telomere length, suggesting that muscle cell turnover was not accelerated despite an expansion of the satellite cell pool. Our findings suggest that combined exercise training elicits beneficial muscular adaptations without impairing important indicators of skeletal muscle regenerative capacity in patients with FSHD. KEY POINTS: A 24week combined exercise training program is a safe and well-tolerated strategy to attenuate skeletal muscle deterioration in facioscapulohumeral muscular dystrophy (FSHD) patients. Markers of histopathology, muscle fibre regeneration and inflammatory infiltrates were not exacerbated following exercise training in FSHD muscle. Here, we show novel data that exercise training in FSHD patients induced muscle fibre hypertrophy and triggered an expansion of the satellite cell pool specifically in fast fibres. Exercise training in these patients is not associated with a shortening of muscle telomere length thereby indicating a preserved capacity for muscle regeneration.

The role of telomere shortening in ambient ozone exposure-related insulin resistance

BackgroundOzone (O3) exposure and telomere shortening are associated with insulin resistance (IR). However, the role of telomere shortening in ambient O3 exposure-related IR is largely unclear. MethodsThe Henan Rural Cohort recruited participants and performed a random forest method to estimate residential O3 concentration. IR was reflected by homeostasis model assessment-IR, quantitative insulin sensitivity check index, triglyceride and glucose index, etc. Generalized linear model, quantile regression model, and mediation effects analysis were utilized to assess the associations of O3 exposure and relative telomere length (RTL) with longitudinal IR markers and their change rates. Furthermore, the role of telomere homeostasis in O3-exposure-induced IR in vivo and in vitro experiments was verified. ResultsO3 exposure was positively associated with longitudinal IR. The proportions of RTL mediated associations between O3 exposure and longitudinal IR markers ranged from 11.92% to 60.36%. O3-exposed mice exhibited a higher glucose load, upregulation of GSK-3β and G-6-Pase expression at mRNA levels, glycogen accumulation reduction, telomere shortening, and decreased telomerase reverse transcriptase activity relative to air-exposed mice. In vitro experiments reveal that overexpression of TERT in HepG2 cells up-regulated G-6-Pase mRNA expression level. ConclusionsImpaired telomere homeostasis may be involved in O3 exposure-related IR via inhibition of glycogen synthesis and acceleration of gluconeogenesis and the specific mechanisms are still further elucidated.

Abstract DP12: Leukocyte Telomere Length as a Predictor of Age-Related Brain Diseases: Evidence from the UK Biobank

Abstract DP12: Leukocyte Telomere Length as a Predictor of Age-Related Brain Diseases: Evidence from the UK Biobank

From infection to immortality: The role of HPV and telomerase in head and neck cancer.

Head and neck squamous cell carcinomas (HNSCCs) represent a heterogeneous group of malignancies with multifactorial aetiologies. High-risk human papillomavirus (hrHPV) infections, particularly HPV16, and the dysregulation of telomerase activity, specifically through its catalytic subunit, telomerase reverse transcriptase (TERT) are among the key contributors to HNSCC development and progression. HPV promotes oncogenesis via the E6 and E7 oncoproteins, which inactivate tumour suppressors TP53 and RB1, leading to unchecked cellular proliferation. Concurrently, telomerase activation plays a critical role in HNSCC by maintaining telomere length, thus enabling cellular immortality, and facilitating tumour development and progression. The interplay between HPV and telomerase is significant; HPV oncoprotein E6 enhances telomerase activity through multiple regulatory mechanisms, including upregulating TERT expression. Beyond telomere maintenance, TERT influences signalling pathways, cellular metabolism, and the tumour microenvironment, contributing to aggressive tumour behaviour and poor prognosis. This review integrates the roles of HPV and telomerase in HNSCC, focusing on their molecular mechanisms and interactions that drive carcinogenesis and influence disease progression. Understanding the synergistic effects of HPV and TERT in HNSCC may be crucial for risk stratification, prognostic assessment, and the development of novel therapeutic strategies targeting these specific molecular pathways.

Pre- and post-lung transplant considerations for patients with ultra-short telomere length.

Pre- and post-lung transplant considerations for patients with ultra-short telomere length.

Telomere Length and Symptoms of Attention Deficit and Hyperactivity Disorder in Children at 6-12 Years.

To explore the association between telomere length (TL) and attention deficit hyperactivity disorder (ADHD) symptoms in children at 6-12 years. Data from 1,759 children belonging to the HELIX project cohorts and the Asturias, Gipuzkoa and Valencia cohorts of INMA project were included. TL was determined by blood sample using a PCR protocol. ADHD symptoms were described by parents using the Conners' Parent Rating Scale-Revised: Short Form. Multiple negative binomial regression models adjusted for potential confounders were used to estimate associations. Overall estimates showed no associations between TL and ADHD symptoms. However, we observed that a longer TL was significantly associated with a lower risk of presenting hyperactivity symptoms in children belonging to the HELIX project (IRR = 0.93, 95% CI [0.87, 0.99]; p = .022). While our study did not find a consistent association between TL and ADHD symptoms across all cohorts, the significant association found within the HELIX cohort suggests that longer TL may be linked to a lower risk of hyperactivity symptoms. Further research is needed to explore this association in more detail.

Diet, lifestyle and telomere length: using Copula Graphical Models on NHANES data.

Telomere length has been related to human health and ageing in multiple studies. However, these studies have analyzed a small set of variables, according to pre-formulated hypotheses. We used data from NHANES 1999-2002 to perform a preregistered cross-sectional analysis. From these four years we selected the participants with available leukocyte telomere length measure and with plausible daily energy intake, leading to a total study population of 7096 participants. Then, we divided the participants in three groups according to age: Young 20-39 (n = 2623), Middle 40-59 (n = 2210), Old 60-84 (n = 2263). On each group we performed Copula Graphical Modelling (CGM) to capture the links between the variables of interest, and we conducted certainty and sensitivity analyses to understand the robustness of the results. Blood levels of C-reactive protein and γ-tocopherol, and intake of caffeine and fibers are inversely related to telomere length across the age strata. Sex, race, smoking, physical activity and indicators of socioeconomic status have almost no direct connection with telomeres; however, they are directly linked to C-reactive protein, which in turn is connected to leukocyte telomere length. C-reactive protein is therefore a possible central mediator of the effect of these factors on telomeres.

Early-life Exposure to Tobacco Smoke and the Risk of Idiopathic Pulmonary Fibrosis: A Population-based Cohort Study.

Tobacco smoking is a well-established risk factor for idiopathic pulmonary fibrosis (IPF), yet the influence of early-life tobacco exposure on future IPF risk remains poorly understood. To test the hypothesis that early-life tobacco exposure may elevate the risk of developing IPF, with this effect potentially modified by genetic susceptibility to IPF and mediated through accelerated biological aging. Using data from over 430,000 participants in the UK Biobank, we performed a prospective cohort study to examine the associations of maternal smoking around birth and age of smoking initiation with IPF risk. We evaluated the combined effects and interactions between early-life tobacco exposure and genetic susceptibility to IPF, quantified using polygenic risk scores. We assessed biological aging, as measured by telomere length and phenotypic age, as potential mediators in the associations between early-life tobacco exposure and IPF risk. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Maternal smoking around birth was associated with a higher risk of IPF (HR: 1.26; 95% CI: 1.11-1.43). Compared to never-smokers, individuals who initiated smoking in childhood (HR: 3.65; 95% CI: 3.02-4.41), adolescence (HR: 2.64; 95% CI: 2.28-3.05), and adulthood (HR: 2.09; 95% CI: 1.79-2.44) exhibited increased IPF risk (P for trend < 0.001). An additive interaction was observed between age of smoking initiation and genetic risk for IPF. Individuals with high genetic risk, maternal smoking exposure, and childhood smoking initiation had a 16-fold greater risk of IPF (HR: 16.47; 95% CI: 9.57-28.32), compared to those with low genetic risk and no tobacco exposure. Telomere length and phenotypic age each mediated approximately 10% of the effect of maternal smoking on IPF, with weaker mediation effects observed for later ages of smoking initiation. Early-life tobacco exposure may elevate the risk of IPF, with effect modified by genetic susceptibility and partially mediated through accelerated biological aging.

The multi-omics signatures of telomere length in childhood

BackgroundTelomere length is an important indicator of biological age and a complex multi-factor trait. To date, the telomere interactome for comprehending the high-dimensional biological aspects linked to telomere regulation during childhood remains unexplored. Here we describe the multi-omics signatures associated with childhood telomere length.MethodsThis study included 1001 children aged 6 to 11 years from the Human Early-life Exposome (HELIX) project. Telomere length was quantified via qPCR in peripheral blood of the children. Blood DNA methylation, gene expression, miRNA expression, plasma proteins and serum and urinary metabolites were measured through microarrays or (semi-) targeted assays. The association between each individual omics feature and telomere length was assessed in omics-wide association analyses. In addition, a literature-guided, sparse supervised integration method was applied to multiple omics, and latent components were extracted as predictors of child telomere length. The association of these latent components with early-life aging risk factors (child lifestyle, body mass index (BMI), exposure to smoking, etc.), were interrogated.ResultsAfter multiple-testing correction, only two CpGs (cg23686403 and cg16238918 at PARD6G gene) out of all the omics features were significantly associated with child telomere length. The supervised multi-omics integration approach revealed robust associations between latent components and child BMI, with metabolites and proteins emerging as the primary contributing features. In these latent components, the contributing molecular features were known as involved in metabolism and immune regulation-related pathways.ConclusionsFindings of this multi-omics study suggested an intricate interplay between telomere length, metabolism and immune responses, providing valuable insights into the molecular underpinnings of the early-life biological aging.

Maternal urinary levels of PAH metabolites, umbilical cord blood telomere length and anthropometric indices in newborns.

The existing evidence indicating that prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with a range of adverse outcomes, including alterations in anthropometric indices, underscores the need for further investigation into the underlying mechanisms. This study aims to examine the effects of prenatal PAH exposure on anthropometric indices and telomere length (TL), as well as to explore whether changes in TL can serve as a predictor of alterations in anthropometric measures. The study was conducted in Shenyang, China, with 2460 pregnant women participating between 2022 and 2023. Maternal urine samples were analyzed for eleven PAH metabolites, and neonatal outcomes, such as birth weight (BW), birth length (BL), and head circumference (HC), were extracted from medical records as anthropometric indices. We employed multiple linear regression (MLR), generalized quantile g-computation (g-comp), Bayesian Kernel Machine Regression (BKMR), and mediation analysis to comprehensively assess the associations between PAH exposure and umbilical TL and neonatal outcomes. Notably, significant negative associations were found between several PAH metabolites and umbilical telomere length (TL). These metabolites included 2-hydroxy naphthalene (2-OH Nap), 1-hydroxy pyrene (1-OH Pyr), 6-hydroxy chrysene (6-OH Chr), 9-hydroxy benzo(a)pyrene (9-OH Bap), and the sum of hydroxylated PAHs (Σ-OH PAHs). Additionally, negative correlations were identified between specific PAH metabolites and HC, although no significant associations were found for BW. Birth weight showed a significant inverse relationship with metabolites such as 1-hydroxy phenanthrene (1-OH Phe), 9-hydroxy phenanthrene (9-OH Phe), and 1-hydroxy naphthalene(1-OH Nap). Results from g-comp analysis and BKMR indicated significant mixture effects of PAHs on umbilical TL and HC, with more heterogeneous effects on BW and BL. Mediation analysis indicated that alterations in umbilical TL partially mediated the associations between PAH exposure and BW and HC. Notably, metabolites such as 2-OH Nap and the Σ-OH PAHs demonstrated substantial mediation effects. Overall, our findings suggest that changes in umbilical TL partially mediate the associations between prenatal PAH exposure and HC and BW, highlighting the complex pathways through which PAH metabolites may influence neonatal development.

Sleep Deprivation and Subchronic Arsenite Exposure Synergistically Induced Skeletal Muscle Aging by Disrupting Melatonin and Cortisol Secretion in Mice

In recent years, the influence of environmental factors on organismal aging has garnered increasing attention. Studies have shown that sleep deprivation and environmental pollutants could accelerate the emergence of multiple organismal aging phenotypes. In addition, studies have shown that chronic exposure to sodium arsenite (iAs) induces skeletal muscle atrophy and the inhibition of melatonin secretion in rats. This study aimed to reveal the synergistic effect of sleep deprivation and arsenite exposure on skeletal muscle aging, including reduced limb grip strength and skeletal muscle mass, along with the serum levels of melatonin (MT) and cortisol (COR) in C57BL/6J mice. The results demonstrated that while exposure to arsenite for 12 weeks or sleep deprivation (SD) for 4 weeks did not exert significant effects on limb grip strength or skeletal muscle mass, their combination exhibited a synergistic effect on skeletal muscle aging. Notably, the iAs+SD group exhibited a significant decline in limb grip strength by Week 12, accompanied by a reduced gastrocnemius muscle mass and muscle index. The pathological analysis showed muscle fiber atrophy, a shift towards slow-twitch muscle fibers (type I), and shortened telomere length. Additionally, oxidative damage was increased in the SD and iAs+SD groups, with decreased levels of SOD and GPx and elevated levels of MDA in the iAs+SD group. The serum MT level and MT/COR ratio were significantly reduced, while the serum COR level was elevated in the iAs+SD group compared to the other groups. A correlation analysis further revealed that the serum MT level and the MT/COR ratio were positively correlated with limb grip strength, muscle index, and telomere length, whereas the serum COR level exhibited negative correlations with these parameters. These findings suggest that sleep deprivation and subchronic exposure to arsenite synergistically induce skeletal muscle aging, and that the disruption of the balance between MT and COR potentially serves as a significant risk factor.

A branching model for intergenerational telomere length dynamics.

We build and study an individual based model of the telomere length's evolution in a population across multiple generations. This model is a continuous time typed branching process, where the type of an individual includes its gamete mean telomere length and its age. We study its Malthusian's behaviour and provide numerical simulations to understand the influence of biologically relevant parameters.

Mathematical model linking telomeres to senescence in Saccharomyces cerevisiae reveals cell lineage versus population dynamics

Telomere shortening ultimately causes replicative senescence. However, identifying the mechanisms driving replicative senescence in cell populations is challenging due to the heterogeneity of telomere lengths and the asynchrony of senescence onset. Here, we present a mathematical model of telomere shortening and replicative senescence in Saccharomyces cerevisiae which is quantitatively calibrated and validated using data of telomerase-deficient single cells. Simulations of yeast populations, where cells with varying proliferation capacities compete against each other, show that the distribution of telomere lengths of the initial population shapes population growth, especially through the distribution of cells’ shortest telomere lengths. We also quantified how factors influencing cell viability independently of telomeres can impact senescence rates. Overall, we demonstrate a temporal evolution in the composition of senescent cell populations—from a state directly linked to critically short telomeres to a state where senescence onset becomes stochastic. This population structure may promote genome instability and facilitate senescence escape.

Telomemore enables single-cell analysis of cell cycle and chromatin condensation.

Single-cell RNA-seq methods can be used to delineate cell types and states at unprecedented resolution but do little to explain why certain genes are expressed. Single-cell ATAC-seq and multiome (ATAC+RNA) have emerged to give a complementary view of the cell state. It is however unclear what additional information can be extracted from ATAC-seq data besides transcription factor binding sites. Here, we show that ATAC-seq telomere-like reads counter-inituively cannot be used to infer telomere length, as they mostly originate from the subtelomere, but can be used as a biomarker for chromatin condensation. Using long-read sequencing, we further show that modern hyperactive Tn5 does not duplicate 9 bp of its target sequence, contrary to common belief. We provide a new tool, Telomemore, which can quantify nonaligning subtelomeric reads. By analyzing several public datasets and generating new multiome fibroblast and B-cell atlases, we show how this new readout can aid single-cell data interpretation. We show how drivers of condensation processes can be inferred, and how it complements common RNA-seq-based cell cycle inference, which fails for monocytes. Telomemore-based analysis of the condensation state is thus a valuable complement to the single-cell analysis toolbox.

A novel TERT variant associated with a telomere biology disorder and challenges in variant classification.

Telomere biology disorders (TBDs) are inherited conditions associated with multisystem manifestations. We describe clinical and functional characterisation of a novel TERT variant. Whole-genome sequencing was performed along with single telomere length analysis (STELA). Telomerase activity and processivity were assessed. A novel TERT variant (K710R) was detected in a patient with classic TBD features showing reduced telomerase activity and processivity. Despite clinical and functional evidence, the variant was classified as a variant of uncertain significance. We have described a novel TERT variant and highlighted the need for further refinement of variant classification specific for TBDs.

Limited evidence of association between dysregulated immune marker levels and telomere length in severe mental disorders.

Accelerated ageing indexed by telomere attrition is suggested in schizophrenia spectrum- (SCZ) and bipolar disorders (BD). While inflammation may promote telomere shortening, few studies have investigated the association between telomere length (TL) and markers of immune activation and inflammation in severe mental disorders. Leucocyte TL defined as telomere template/amount of single-copy gene template (T/S ratio), was determined in participants with SCZ (N = 301) or BD (N = 211) and a healthy control group (HC, N = 378). TL was analysed with linear regressions for associations with levels of 12 immune markers linked to SCZ or BD. Adjustments were made for a broad range of potential confounding variables. TL was measured by quantitative polymerase chain reaction (qPCR) and the immune markers were measured by enzyme immunoassays. A positive association between levels of soluble tumour necrosis factor receptor 1A (sTNF-R1) and TL in SCZ (β = 0.191, p = 0.012) was observed. Plasma levels of the other immune markers were not significantly associated with TL in the BD, SCZ or HC groups. There was limited evidence of association between immune markers and TL in SCZ and BD. The results provide little support for involvement of immune dysregulation, as reflected by current systemic markers, in telomere attrition-related accelerated ageing in severe mental disorders.

Telomere Length and Oxidative Damage in Children and Adolescents with Autism Spectrum Disorder: A Systematic Review and Meta-Analysis.

Autism spectrum disorder (ASD) has been reported to confer an increased risk of natural premature death. Telomere erosion caused by oxidative stress is a common consequence in age-related diseases. However, whether telomere length (TL) and oxidative indicators are significantly changed in ASD patients compared with controls remains controversial. The aim of this study was to determine the associations of ASD with TL and oxidative indicators by performing a meta-analysis of all published evidence. The PubMed and Embase databases were searched for articles published up to April, 2024. The effect size was expressed as standardized mean difference (SMD) and 95% confidence interval (CI) via Stata 15.0 software. Thirty-nine studies were included. Pooled results showed that compared with controls, children and adolescents with ASD were associated with significantly shorter TL (SMD = -0.48; 95% CI = -0.66- -0.29; p < 0.001; particularly in males), lower total antioxidant capacity (TAC: SMD = -1.15; 95% CI = -2.01- -0.30; p = 0.008), and higher oxidative DNA (8-hydroxy-2'-deoxyguanosine, 8-OHdG: SMD = 0.63; 95% CI = 0.03-1.23; p = 0.039), lipid (hexanolyl-lysine, HEL: SMD = 0.37; 95% CI = 0.13-0.62; p = 0.003), and protein (3-nitrotyrosine, 3-NT: SMD = 0.86; 95% CI = 0.21-1.51; p = 0.01; dityrosine, DT: SMD = 0.66; 95% CI = 0.521-0.80; p < 0.01) damage. There were no significant differences between ASD and controls in 8-isoprostane and oxidative stress index after publication bias correction, and in N-formylkynurenine during overall meta-analysis. TL, 8-OHdG, TAC, HEL, 3-NT, and DT represent potential biomarkers for prediction of ASD in children and adolescents.