Telomere Length in Peripheral Blood Leukocytes Is Associated with Severity of Biliary Atresia

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.

Is the liver resilient to the process of ageing?

The liver's unique regenerative capacity, immunotolerant feature, and polyploidy status distinguish it as a metabolic organ unlike any other in the body. Despite aging, the liver generally exhibits fewer pathological abnormalities than other organs (such as the kidney), maintaining its functions near-normal balanced manner. Subtle changes in the liver, including reduced blood flow, detoxification alterations, pseudo-capillarization, and lipofuscin deposition, may occur with chronological age. Research indicates that carefully selected liver grafts from octogenarian donors can perform well post-transplant, emphasizing instances where age doesn't necessarily compromise liver function. Notably, a recent report suggests that the liver is a youthful organ, with hepatocytes averaging an age of only 3 years. Despite the liver's impressive regenerative capabilities and cellular reserve, a lingering question persists: how does the liver maintain its youthful characteristic amidst the chronological aging of the entire organism? The various adaptive mechanism possibly include:(a) cellular hypertrophy to maintain physiological capacity even before proliferation initiates, (b) the "ploidy conveyor" as a genetic adaptation to endure aging-related stress, (c) sustained telomere length indicative of youthfulness (d) active extracellular matrix remodelling for normal cellular functioning, (e) Mitochondria-Endoplasmic Reticulum based metabolic adaptation and (c) cellular plasticity as fitness mechanisms for healthy aging. However, it is crucial to note that aged livers may have compromised regenerative capacity and chronic liver disease is often associated with declining function due to premature hepatocyte senescence. This review delves into varied cellular adaptations sustaining liver homeostasis with chronological aging and briefly explores the role of accelerated hepatocyte aging as a precursor to chronic liver disease.

Telomere dysfunction in some pediatric congenital and growth-related diseases

Telomere wear and dysfunction may lead to aging-related diseases. Moreover, increasing evidence show that the occurrence, development, and prognosis of some pediatric diseases are also related to telomere dysfunction. In this review, we systematically analyzed the relationship between telomere biology and some pediatric congenital and growth-related diseases and proposed new theoretical basis and therapeutic targets for the treatment of these diseases.

Telomere Length Is Correlated with Resting Metabolic Rate and Aerobic Capacity in Women: A Cross-Sectional Study

This study investigated the associations between relative telomere length (RTL) and resting metabolic rate (RMR), resting fat oxidation (RFO), and aerobic capacity and whether oxidative stress and inflammation are the underlying mechanisms in sedentary women. We also aimed to determine whether the correlations depend on age and obesity. Sixty-eight normal weight and 66 obese women participated in this study. After adjustment for age, energy expenditure, energy intake, and education level, the RTL of all participants was negatively correlated with absolute RMR (RMRAB) and serum high-sensitivity C-reactive protein (hsCRP) concentration, and positively correlated with maximum oxygen consumption (V˙O2max) (all p < 0.05). After additional adjustment for adiposity indices and fat-free mass (FFM), RTL was positively correlated with plasma vitamin C concentration (p < 0.05). Furthermore, after adjustment for fasting blood glucose concentration, RTL was negatively correlated with age and positively correlated with V˙O2max (mL/kg FFM/min). We found that normal weight women had longer RTL than obese women (p < 0.001). We suggest that RTL is negatively correlated with RMRAB and positively correlated with aerobic capacity, possibly via antioxidant and anti-inflammatory mechanisms. Furthermore, age and obesity influenced the associations. We provide useful information for the management of promotion strategies for health-related physical fitness in women.

Cellular senescence in the cholangiopathies: a driver of immunopathology and a novel therapeutic target

The cholangiopathies are a group of liver diseases that affect cholangiocytes, the epithelial cells that line the bile ducts. Biliary atresia (BA), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are three cholangiopathies with significant immune-mediated pathogenesis where chronic inflammation and fibrosis lead to obliteration of bile ducts and eventual liver cirrhosis. Cellular senescence is a state of cell cycle arrest in which cells become resistant to apoptosis and profusely secrete a bioactive secretome. Recent evidence indicates that cholangiocyte senescence contributes to the pathogenesis of BA, PBC, and PSC. This review explores the role of cholangiocyte senescence in BA, PBC, and PSC, ascertains how cholangiocyte senescence may promote a senescence-associated immunopathology in these cholangiopathies, and provides the rationale for therapeutically targeting senescence as a treatment option for BA, PBC, and PSC.

Biliary Epithelial Senescence in Liver Disease: There Will Be SASP

Cellular senescence is a pathophysiological phenomenon in which proliferative cells enter cell cycle arrest following DNA damage and other stress signals. Natural, permanent DNA damage can occur after repetitive cell division; however, acute stress or other injuries can push cells into premature senescence and eventually a senescence-associated secretory phenotype (SASP). In recent years, there has been increased evidence for the role of premature senescence in disease progression including diabetes, cardiac diseases, and end-stage liver diseases including cholestasis. Liver size and function change with aging, and presumably with increasing cellular senescence, so it is important to understand the mechanisms by which cellular senescence affects the functional nature of the liver in health and disease. As well, cells in a SASP state secrete a multitude of inflammatory and pro-fibrogenic factors that modulate the microenvironment. Cellular SASP and the associated, secreted factors have been implicated in the progression of liver diseases, such as cholestatic injury that target the biliary epithelial cells (i.e., cholangiocytes) lining the bile ducts. Indeed, cholangiocyte senescence/SASP is proposed to be a driver of disease phenotypes in a variety of liver injuries. Within this review, we will discuss the impact of cholangiocyte senescence and SASP in the pathogenesis of cholestatic disorders.

Cellular senescence in liver fibrosis: Implications for age-related chronic liver diseases

INTRODUCTION

New insights indicate a causative link between cellular senescence and liver fibrosis. Senescent hepatic stellate cells (HSCs) facilitate fibrosis resolution, while senescence in hepatocytes and cholangiocytes acts as a potent mechanism driving liver fibrogenesis. In many clinical studies, telomeres and mitochondrial DNA contents, which are both aging biomarkers, were reportedly associated with a degree of liver fibrosis in patients with chronic liver diseases (CLDs); this highlights their potential as biomarkers for liver fibrogenesis. A deeper understanding of mechanisms underlying multi-step progression of senescence may yield new therapeutic strategies for age-related chronic liver pathologies.

AREAS COVERED

This review examines the recent findings from preclinical and clinical studies on mechanisms of senescence in liver fibrogenesis and its involvement in liver fibrosis. A comprehensive literature search in electronic databases consisting of PubMed and Scopus from inception to 31 August 2021 was performed.

EXPERT OPINION

Cellular senescence has diagnostic, prognostic, and therapeutic potential in progressive liver complications, especially liver fibrosis. Stimulating or reinforcing the immune response against senescent cells may be a promising and forthright biotherapeutic strategy. This approach will need a deeper understanding of the immune system's ability to eliminate senescent cells and the molecular and cellular mechanisms underlying this process.

Biomarkers for the diagnosis and post-Kasai portoenterostomy prognosis of biliary atresia: a systematic review and meta-analysis

To evaluate the accuracy of biomarkers for the early diagnosis of biliary atresia (BA) and prognostic stratification after Kasai portoenterostomy (KPE). We conducted a systematic review of PubMed, Web of Science, Embase, Scopus and OVID for English literature reporting BA biomarkers published before August 2020. Screening, data extraction, and quality assessment were performed in duplicate. A total of 51 eligible studies were included in the systematic review, and data from 12 (4182 subjects) were extracted for meta-analysis regarding the following 2 domains: (1) serum matrix metallopeptidase-7 (MMP-7), interleukin33 (IL-33) and γ-glutamyl transferase (GGT) to differentiate BA from non-BA; (2) the aspartate aminotransferase to platelet ratio index (APRi) to predict post-KPE liver fibrosis/cirrhosis. The summary sensitivity, specificity and area under the curve (AUC) of MMP-7 for diagnosing BA were 96%, 91% and 0.9847, respectively, and those of GGT were 80%, 79% and 0.9645, respectively. The summary sensitivity and specificity of IL-33 for diagnosing BA were 77% and 85%, respectively. The summary sensitivity and specificity of APRi for predicting post-KPE liver fibrosis were 61% and 80%, respectively, and the summary sensitivity, specificity and AUC of APRi for predicting post-KPE cirrhosis were 78%, 83% and 0.8729, respectively. Moreover, good evidence was shown in investigations of serum IL-18 and IL-33 in distinguishing BA from healthy controls, serum IL-18 for prognosis of post-KPE persistent jaundice, and serum hyaluronic acid and MMP-7 for prognosis of post-KPE significant liver fibrosis. MMP-7, IL-33 and GGT are useful biomarkers to assist in the diagnosis of BA. APRi might be used to predict post-KPE significant liver fibrosis and cirrhosis. These noninvasive biomarkers can be integrated into the management protocol of BA.

Telomere length and outcome of treatment for pulmonary tuberculosis in a gold mining community

Telomere length (TL) is a marker of ageing and mitochondrial DNA (mtDNA) is an early marker of inflammation caused by oxidative stress. We determined TL and mtDNA content among active pulmonary tuberculosis (PTB) patients to assess if these cellular biomarkers differed between artisanal miners and non-miners, and to assess if they were predictive of treatment outcome. We conducted a prospective cohort study from August 2018 to May 2019 involving newly diagnosed PTB patients at three outpatient TB clinics in a rural Democratic Republic of Congo. We measured relative TL and mtDNA content in peripheral blood leukocytes (at inclusion) via qPCR and assessed their association with PTB treatment outcome. We included 129 patients (85 miners and 44 non-miners) with PTB (median age 40 years; range 5-71 years, 22% HIV-coinfected). For each increase in year and HIV-coinfection, TL shortened by - 0.85% (- 0.19 to - 0.52) (p ≤ 0.0001) and - 14% (- 28.22 to - 1.79) (p = 0.02) respectively. Independent of these covariates, patients with longer TL were more likely to have successful TB treatment [adjusted hazard ratio; 95% CI 1.27 for a doubling of leucocyte telomere length at baseline; 1.05-1.44] than patients with a shorter TL. Blood mtDNA content was not predictive for PTB outcome. For a given chronological age, PTB patients with longer telomeres at time of diagnosis were more likely to have successful PTB treatment outcome.

Serum anti-inflammatory and inflammatory markers have no causal impact on telomere length: a Mendelian randomization study

INTRODUCTION

The relationship between inflammatory and anti-inflammatory markers and telomere length (TL), a biological index of aging, is still poorly understood. By applying a 2-sample Mendelian randomization (MR), we investigated the causal associations between adiponectin, bilirubin, C-reactive protein (CRP), leptin, and serum uric acid (SUA) with TL.

MATERIAL AND METHODS

MR was implemented by using summary-level data from the largest ever genome-wide association studies (GWAS) conducted on our interested exposure and TL. Inverse variance weighted method (IVW), weighted median (WM)-based method, MR-Egger, MR-Robust Adjusted Profile Score (RAPS), and MR-Pleiotropy RESidual Sum and Outlier (PRESSO) were applied. Sensitivity analysis was conducted using the leave-one-out method.

RESULTS

With regard to adiponectin, CRP, leptin, and SUA levels, we found no effect on TL for all 4 types of tests (all p > 0.108). Results of the MR-Egger (p = 0.892) and IVW (p = 0.124) showed that bilirubin had no effect on telomere maintenance, whereas the results of the WM (p = 0.030) and RAPS (p = 0.022) were negative, with higher bilirubin concentrations linked to shorter TL. There was a low likelihood of heterogeneity for all the estimations, except for bilirubin (IVW p = 0.026, MR Egger p = 0.018). MR-PRESSO highlighted no outlier. For all the estimations, we observed negligible intercepts that were indicative of low likelihood of the pleiotropy (all p > 0.161). The results of leave-one-out method demonstrated that the links are not driven because of single nucleotide polymorphisms (SNPs).

CONCLUSIONS

Our results highlight that neither the anti-inflammatory nor pro-inflammatory markers tested have any significant causal effect on TL. The casual role of bilirubin on TL still needs to be investigated.

Active surveillance in prostate cancer management: where do we stand now?

Prostate cancer (PCa) is the most common cancer in men, with a steadily rising incidence, affecting on average one in six men during their lifetime. The increase in morbidity is related to the increasing overall life expectancy, prostate-specific antigen testing, implementation of new molecular markers for cancer detection and the more frequent application of multiparametric magnetic resonance imaging. There is growing evidence demonstrating that active surveillance (AS) is an alternative to immediate intervention in patients with very low- and low-risk prostate cancer. Ongoing reports from multiple studies have consistently demonstrated a very low rate of metastases and prostate cancer specific mortality in selected cohorts of patients. As a matter of fact, AS has been adopted by many institutions as a safe and effective management strategy. The aim of our review is to summarize the contemporary data on AS in patients affected with PCa with the intention to present the most clinically useful and pertinent AS protocols.

Telomere shortening is associated with poor physical performance in knee osteoarthritis

Telomere length is a hallmark characteristic of ageing and age-related diseases. Osteoarthritis (OA) is the most common cause of joint pain and physical disability in the elderly. Previous studies have revealed the role of telomere shortening in OA; however, the relationship between telomere length, muscle strength and physical performance in knee OA patients remains unknown. The aim of the present study was to investigate the association of telomere length and physical performance in patients with knee OA. A total of 202 patients with knee OA and 60 healthy controls were enrolled in the study. The quality of life was assessed using Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and Short Form Health Survey. The skeletal muscle mass was examined using bioelectrical impedance analysis, while the muscle strength was analyzed using hand grip force and isometric knee extension force. The physical performance of patients with knee OA was also investigated using gait speed, Timed up and go test (TUGT), Sit to stand test and 6-min walk test (6MWT). Blood leukocyte relative telomere length (RTL) was assessed using real time quantitative PCR. The mean blood leukocyte RTL in knee OA subjects was significantly lower compared with healthy controls (P<0.001). Knee OA patients with RTL values in the lowest quartile had a slow gait speed (P=0.006) and prolonged TUGT time (P=0.03). Multivariate regression analyses and multiple logistic regression analyses adjusted for age, sex, waist circumference, body mass index, fat mass, skeletal muscle index and the total WOMAC demonstrated that gait speed, TUGT and 6MWT were associated with longer RTL (P-trend<0.05). These findings suggested that poorer physical performance was associated with shorter RTL. Therefore, leukocyte telomere length and physical performance tests, especially gait speed, TUGT and 6MWT, could predict the health status and quality of life in patients with knee OA.

Leukocyte telomere length as a diagnostic biomarker for anti-tuberculosis drug-induced liver injury

Despite being relatively rare, anti-tuberculosis drug-induced liver injury (ATDILI) is a leading cause of acute liver failure and a major reason for treatment discontinuation, because of no specific and selective markers for ATDILI. Herein, this study aimed to investigate whether telomere length, a biological indicator of age-related diseases, is associated with ATDILI outcomes and could serve as an early ATDILI biomarker. Relative telomere length (RTL) in blood leukocyte of 100 age- and gender-matched healthy controls, 49 tuberculosis patients with ATDILI, and 53 tuberculosis patients with non-ATDILI was quantified using real-time polymerase chain reaction. Both tuberculosis patients with and without ATDILI had significantly shorter RTL than healthy controls. Compared with tuberculosis patients with non-ATDILI, RTL in those with ATDILI was significantly increased. Longer RTL was found to be significantly associated with increased susceptibility to ATDILI. Multivariate linear regression analysis showed that an increment in RTL was independently correlated with elevated values of aspartate aminotransferase and alanine aminotransferase assessed within 60 days after anti-tuberculosis treatment. Kaplan-Meier curve analysis demonstrated that longer RTL was associated with elevated rates of hepatotoxicity in tuberculosis patients. Receiver-operating characteristic curve analysis unveiled a diagnostic accuracy of RTL as a novel indicator for ATDILI progression (AUC = 0.73), which yielded more sensitive and specific values than traditional liver biomarkers including serum enzyme activities of aminotransferases measured within 7 days after treatment with anti-tuberculosis regimens. Collectively, aberrant RTL in blood leukocyte would reflect hepatotoxicity induced by anti-tuberculosis agents and might have a potential biomarker for early ATDILI progression.

Leukocyte mitochondrial DNA copy number as a potential biomarker indicating poor outcome in biliary atresia and its association with oxidative DNA damage and telomere length

Biliary atresia (BA) is a chronic obstructive liver disease, leading to advanced liver failure. Mitochondria dysfunction-mediated aberrant telomere length has been implicated in various pathological processes including cholestasis. Herein, we aimed to investigate associations between mitochondrial DNA (mtDNA) copy number, oxidative DNA damage, telomere length, and disease severity in BA patients. mtDNA copy number and relative telomere length (RTL) were assessed using real-time PCR. Circulating 8-hydroxy-2'-deoxyguanosine (8-OHdG) was measured using ELISA. Our findings showed that BA patients had significantly lower mtDNA copy number and RTL than healthy controls, whereas plasma 8-OHdG levels were significantly elevated in BA patients. mtDNA copy number was remarkably reduced in advanced BA patients. Furthermore, mtDNA copy number was independently associated with age and degree of liver fibrosis in BA patients. Decreased mtDNA copy number was significantly associated with elevated risks of BA, severe fibrosis, jaundice, and hepatic dysfunction. Low mtDNA copy number can be utilized to distinguish patients with poor-outcome from those with good-outcome. Survival curve analysis revealed that low mtDNA copy number was significantly associated with poor survival of BA patients. Interestingly, there was a positive association between mtDNA copy number and plasma 8-OHdG in BA patients, while a negative association of mtDNA copy number with RTL was observed in BA patients. Alternatively, RTL was negatively correlated with plasma 8-OHdG in BA patients. These data demonstrated relationships between leukocytes mtDNA copy number, oxidative stress, telomere length, and clinical parameters in BA patients. Accordingly, our findings indicate that mtDNA copy number may serve as a potential biomarker reflecting BA severity.

Correlation between hepatic oxidative damage and clinical severity and mitochondrial gene sequencing results in biliary atresia

AIM

To assess the level of hepatic oxidative damage and its correlation with clinical severity in biliary atresia (BA), and to understand BA mitochondrial gene sequencing.

METHODS

Forty-eight BA patients and 28 control subjects (20 hepatoblastoma and 8 cholestasis patients) were enrolled. Hepatic oxidative damage was assessed by the expression of oxidation and antioxidant genes, and the correlation between oxidative damage and BA incidence, liver inflammation, and fibrosis was evaluated. Moreover, 8-hydroxyguanine (8-OHdG), mitochondrial DNA (mtDNA) copy number, and mitochondrial gene sequences were determined to evaluate oxidative mtDNA damage in BA.

RESULTS

The expression of oxidation gene cytochrome b-245 beta chain (CYBB) in BA was significantly increased and patients with a higher CYBB expression had the higher risk of BA incidence, liver inflammation, and cirrhosis. However, the expression of antioxidant genes was significantly decreased, and glutathione S-transferase alpha 1 (GSTA1) negatively correlated with BA incidence and cirrhosis. When GSTA1 mRNA expression was <0.5487, the sensitivity was 80.85% and the specificity was 80% for BA diagnosis. Moreover, 8-OHdG was increased, whereas mtDNA copy number was significantly decreased in BA. Using mitochondrial gene sequencing, 10 mutation sites were identified, and one family showed a maternal inheritance in genetic loci 15 326.

CONCLUSIONS

In BA, oxidative damage positively correlated with BA incidence, liver inflammation, and cirrhosis. GSTA1 could be a novel diagnostic indicator. Genetic loci 15 326 could be a maternal genetic mutation site. Taken together, antioxidation therapy after Kasai surgery might have great potential in relieving liver inflammation and fibrosis in BA patients.

Relative telomere length and oxidative DNA damage in hypertrophic ligamentum flavum of lumbar spinal stenosis

Background

Lumbar spinal stenosis (LSS) is a common cause of low back pain with degenerative spinal change in older adults. Telomeres are repetitive nucleoprotein DNA sequences of TTAGGG at the ends of chromosomes. Oxidative stress originates from an imbalance in pro-oxidant and antioxidant homeostasis that results in the production of reactive oxygen species (ROS). The purpose of this study was to investigate relative telomere length (RTL) and oxidative DNA damage in ligamentum flavum (LF) tissue from LSS patients.

Methods

Forty-eight patients with LSS participated in this study. Genomic DNA from non-hypertrophic and hypertrophic LF tissue were analyzed by real-time polymerase chain reaction for relative telomere length (RTL). 8-hydroxy 2'-deoxygaunosine (8-OHdG) levels were determined by using enzyme-linked immunosorbent assay. We cultivated LF fibroblast cells from patients in different ages (61, 66, and 77 years). After each cultivation cycle, we examined RTL and senescence-associated β-galactosidase (SA-β-gal) expression.

Results

The hypertrophic LF had significantly lower RTL than non-hypertrophic LF (P = 0.04). The levels of 8-OHdG were significantly higher in hypertrophic LF compared to non-hypertrophic LF (P = 0.02). With advancing cell culture passage, the number of cells in each passage was significantly lower in hypertrophic LF fibroblast cells than non-hypertrophic LF fibroblast cells. When evaluated with SA-β-gal staining, all senescent LF fibroblast cells were observed at earlier passages in hypertrophic LF compared with non-hypertrophic LF fibroblast cells.

Discussion

Our results showed that patients with LSS displayed an accelerated RTL shortening and high oxidative stress in hypertrophic LF. These findings implied that telomere shortening and oxidative stress may play roles in the pathogenesis of hypertrophic LF in lumbar spinal stenosis.

Global methylation, oxidative stress, and relative telomere length in biliary atresia patients

Alu and LINE-1 elements are retrotransposons with a ubiquitous presence in the human genome that can cause genomic instability, specifically relating to telomere length. Genotoxic agents may induce methylation of retrotransposons, in addition to oxidative DNA damage in the form of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Methylation of retrotransposons induced by these agents may contribute to biliary atresia (BA) etiology. Here, we investigated correlations between global methylation, 8-OHdG, and relative telomere length, as well as reporting on Alu and LINE-1 hypomethylation in BA patients. Alu and LINE-1 hypomethylation were found to be associated with elevated risk of BA (OR = 4.07; 95% CI: 2.27-7.32; P < 0.0001 and OR = 3.51; 95% CI: 1.87-6.59; P < 0.0001, respectively). Furthermore, LINE-1 methylation was associated with liver stiffness in BA patients (β coefficient = -0.17; 95% CI: -0.24 to -0.10; P < 0.0001). Stratified analysis revealed negative correlations between Alu and LINE-1 methylation and 8-OHdG in BA patients (P < 0.0001). In contrast, positive relationships were identified between Alu and LINE-1 methylation and relative telomere length in BA patients (P < 0.0001). These findings suggest that retrotransposon hypomethylation is associated with plasma 8-OHdG and telomere length in BA patients.