Leucocyte telomere shortening is associated with nonalcoholic fatty liver disease-related advanced fibrosis

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: (1) 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 (2) 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.

Frailty and risk of metabolic dysfunction-associated steatotic liver disease and other chronic liver diseases

BACKGROUND & AIMS

Frailty is associated with multiple morbidities. However, its effect on chronic liver diseases remains largely unexplored. This study evaluated the association of frailty with the risk of incident metabolic dysfunction-associated steatotic liver disease (MASLD), cirrhosis, liver cancer, and liver-related mortality.

METHODS

A total of 339,298 participants without prior liver diseases from the UK Biobank were included. Baseline frailty was assessed by physical frailty and the frailty index, categorizing participants as non-frail, prefrail, or frail. The primary outcome was MASLD, with secondary outcomes, including cirrhosis, liver cancer, and liver-related mortality, confirmed through hospital admission records and death registries.

RESULTS

During a median follow-up of 11.6 years, 4,667 MASLD, 1,636 cirrhosis, 257 liver cancer, and 646 liver-related mortality cases were identified. After multivariable adjustment, the risk of MASLD was found to be higher in participants with prefrailty (physical frailty: hazard ratio [HR] 1.66, 95% CI 1.40-1.97; frailty index: HR 2.01, 95% CI 1.67-2.42) and frailty (physical frailty: HR 3.32, 95% CI 2.54-4.34; frailty index: HR 4.54, 95% CI 3.65-5.66) than in those with non-frailty. Similar results were also observed for cirrhosis, liver cancer, and liver-related mortality. Additionally, the frail groups had a higher risk of MASLD, which was defined as MRI-derived liver proton density fat fraction >5%, than the non-frail group (physical frailty: odds ratio 1.64, 95% CI 1.32-2.04; frailty index: odds ratio 1.48, 95% CI 1.30-1.68).

CONCLUSIONS

Frailty was associated with an increased risk of chronic liver diseases. Public health strategies should target reducing chronic liver disease risk in frail individuals.

IMPACT AND IMPLICATIONS

While frailty is common and associated with a poor prognosis in people with MASLD (metabolic dysfunction-associated steatotic liver disease) and advanced chronic liver diseases, its impact on the subsequent risk of these outcomes remains largely unexplored. Our study showed that frailty was associated with increased risks of MASLD, cirrhosis, liver cancer, and liver-related mortality. This finding suggests that assessing frailty may help identify a high-risk population vulnerable to developing chronic liver diseases. Implementing strategies that target frailty could have major public health benefits for liver-related disease prevention.

Association of leukocyte telomere length with the risk of digestive diseases: A large-scale cohort study

BACKGROUND

Leukocyte telomere length (LTL) shortening, a biomarker of telomere attrition, has been linked to multiple diseases. However, the relationship between LTL and digestive diseases remains uncertain. This study aimed to investigate the association between LTL and the risk of digestive diseases.

METHODS

A cohort analysis of over 500,000 participants from the UK Biobank (UKB) between 2006 and 2021 was conducted to estimate the associations of LTL with more than 90 common digestive diseases. LTL was quantified using multiplex quantitative polymerase chain reaction, and cases of each disease were determined according to inpatient and primary care data. Multivariable Cox proportional hazards regression analysis was used to evaluate the associations of LTL with the risk of digestive diseases. Furthermore, such associations were also evaluated after stratification by sex and ethnicity.

RESULTS

After a mean follow-up time of 11.8 years, over 20 International Classification of Diseases, 10th Revision ( ICD-10 ) codes were showed to be associated with telomere attrition. LTL shortening is associated with an increased risk of several digestive diseases, including gastroesophageal reflux disease (K21: hazard ratio [HR] = 1.30, 95% confidence interval [95% CI]: 1.19-1.42), esophageal ulcer (K221: HR = 1.81, 95% CI: 1.22-2.71), Barrett's esophagus (K227: HR = 1.58, 95% CI: 1.14-2.17), gastritis (K29: HR = 1.39, 95% CI: 1.26-1.52), duodenal ulcer (K26: HR = 1.55, 95% CI: 1.14-2.12), functional dyspepsia (K30X: HR = 1.36, 95% CI: 1.06-1.69), non-alcoholic fatty liver disease (NAFLD) (K760: HR = 1.39, 95% CI: 1.09-1.78), liver cirrhosis (K74: HR = 4.73, 95% CI: 3.27-6.85), cholangitis (K830: HR = 2.55, 95% CI: 1.30-5.00), and hernia (K43: HR = 1.50, 95% CI: 1.17-1.94; K44: HR = 1.29, 95% CI: 1.17-1.42). The risk of rectal polyps (K621: HR = 0.77, 95% CI: 0.63-0.92) decreased per unit shortening of LTL.

CONCLUSIONS

This study suggests that LTL shortening is associated with an increased risk of most digestive diseases except for rectal polyps. These findings may provide some clues for understanding the pathogenesis of digestive diseases.

Cellular senescence and its pathogenic and therapeutic implications in autoimmune hepatitis

INTRODUCTION

Senescent cells are characterized by replicative arrest and phenotypes that produce diverse pro-inflammatory and pro-oxidant mediators. The senescence of diverse hepatic cell types could constitute an unrecognized pathogenic mechanism and prognostic determinant in autoimmune hepatitis. The impact of cellular senescence in autoimmune hepatitis is unknown, and it may suggest adjunctive management strategies.

AREAS COVERED

This review describes the molecular mechanisms of cellular senescence, indicates its diagnostic features, suggests its consequences, presents possible therapeutic interventions, and encourages investigations of its pathogenic role and management in autoimmune hepatitis. Treatment prospects include elimination or reversal of senescent cells, generation of ectopic telomerase, reactivation of dormant telomerase, neutralization of specific pro-inflammatory secretory products, and mitigation of the effects of mitochondrial dysfunction.

EXPERT OPINION

The occurrence, nature, and consequences of cellular senescence in autoimmune hepatitis must be determined. The senescence of diverse hepatic cell types could affect the outcome of autoimmune hepatitis by impairing hepatic regeneration, intensifying liver inflammation, and worsening hepatic fibrosis. Cellular senescence could contribute to suboptimal responses during conventional glucocorticoid-based therapy. Interventions that target specific pro-inflammatory products of the senescent phenotype or selectively promote apoptosis of senescent cells may be preferred adjunctive treatments for autoimmune hepatitis depending on the cancer risk.

Telomere length and mortality in lean MAFLD: the other face of metabolic adaptation

BACKGROUND AND AIMS

Healthy weight (lean) patients with metabolic dysfunction-associated fatty liver disease (MAFLD) have a more favorable metabolic and histological profile in cross-sectional studies compared with their non-lean counterparts. Paradoxically, they also have higher overall mortality. The underpinning pathophysiology of this paradox is not understood. Telomere attrition is associated with increased mortality in various diseases.

METHODS

We investigated the role of telomere length in the pathogenesis of lean MAFLD in cohorts with biopsy-proven MAFLD (n = 303). We measured serum malondialdehyde (MDA) levels and hepatic 8-hydroxydeoxyguanosine (8-OHdG) and 4-hydroxy-2-nonenal (4-HNE) expression (reactive oxygen species (ROS) markers), growth/differentiation factor-15 (GDF-15) and tested the effect of H2O2 on telomere length and activity in hepatocyte cell lines. The association between leukocyte telomere length and mortality was examined.

RESULTS

Telomere length was significantly lower in patients with lean MAFLD (p < 0.001). They also demonstrated an increase in ROS levels and decreases in GDF-15. H2O2 induced telomere shortening and reducing telomere activity in hepatocyte cell lines. We subsequently confirmed that telomere length shortening at baseline is associated with increased hazards of all-cause mortality; the deleterious effect was more profound in lean people.

CONCLUSION

Differences in telomere length in part explain the increased mortality of lean compared to non-lean patients with MAFLD. The effect is in part mediated through ROS activation and provide opportunities for therapy.

Metabolic dysfunction-associated liver disease and diabetes: Matrix remodeling, fibrosis, and therapeutic implications

Metabolic dysfunction-associated liver disease (MASLD) and steatohepatitis (MASH) are becoming the most common causes of chronic liver disease in the United States and worldwide due to the obesity and diabetes epidemics. It is estimated that by 2030 close to 100 million people might be affected and patients with type 2 diabetes are especially at high risk. Twenty to 30% of patients with MASLD can progress to MASH, which is characterized by steatosis, necroinflammation, hepatocyte ballooning, and in advanced cases, fibrosis progressing to cirrhosis. Clinically, it is recognized that disease progression in diabetic patients is accelerated and the role of various genetic and epigenetic factors, as well as cell-matrix interactions in fibrosis and stromal remodeling, have recently been recognized. While there has been great progress in drug development and clinical trials for MASLD/MASH, the complexity of these pathways highlights the need to improve diagnosis/early detection and develop more successful antifibrotic therapies that not only prevent but reverse fibrosis.

Leukocyte telomere length in subjects with metabolic dysfunction-associated steatotic liver disease

BACKGROUND AND STUDY AIMS

This study aimed to examine the association between peripheral leukocyte telomere length and indicators of metabolic abnormalities in subjects with metabolic dysfunction-associated steatotic liver disease (MASLD) assessed by magnetic resonance imaging (MRI).

PATIENTS AND METHODS

This cross-sectional study included adults over 20 years with body mass index (BMI) of over >25 kg/m2 and sonographic evidence of hepatic steatosis. The subjects were evaluated by clinical and biochemical variables, determination of hepatic fat fraction by MRI and relative peripheral leukocyte telomere length by quantitative real-time polymerase chain reaction.

RESULTS

Thirty-two subjects (22 men and 10 women) with MASLD were included, with a median age of 40 years, median BMI of 33.75 kg/m2, median HFF 19 %, and median relative T/S ratio of 0.64. Subjects with relative T/S ratio below the median had significantly higher age, lower BMI, higher AST serum levels, higher GGT serum levels, lower serum ferritin levels, and higher FIB4 score. In a multivariable logistic regression model considering relative T/S ratio below or above the median only age was significantly associated with relative T/S ratio. Our findings suggest that age is the most important factor associated with telomere length among subjects with MASLD.

CONCLUSION

Our findings suggest that age is the most important factor associated with telomere length among subjects with MASLD.

Revealing the Hidden Impacts: Insights into Biological Aging and Long-Term Effects in Pauci- and Asymptomatic COVID-19 Healthcare Workers

This study explores the role of inflammation and oxidative stress, hallmarks of COVID-19, in accelerating cellular biological aging. We investigated early molecular markers-DNA methylation age (DNAmAge) and telomere length (TL)-in blood leukocytes, nasal cells (NCs), and induced sputum (IS) one year post-infection in pauci- and asymptomatic healthcare workers (HCWs) infected during the first pandemic wave (February-May 2020), compared to COPD patients, model for "aged lung". Data from questionnaires, Work Ability Index (WAI), blood analyses, autonomic cardiac balance assessments, heart rate variability (HRV), and pulmonary function tests were collected. Elevated leukocyte DNAmAge significantly correlated with advancing age, male sex, daytime work, and an aged phenotype characterized by chronic diseases, elevated LDL and glycemia levels, medications affecting HRV, and declines in lung function, WAI, lymphocyte count, hemoglobin levels, and HRV (p < 0.05). Increasing age, LDL levels, job positions involving intensive patient contact, and higher leukocyte counts collectively contributed to shortened leukocyte TL (p < 0.05). Notably, HCWs exhibited accelerated biological aging in IS cells compared to both blood leukocytes (p ≤ 0.05) and NCs (p < 0.001) and were biologically older than COPD patients (p < 0.05). These findings suggest the need to monitor aging in pauci- and asymptomatic COVID-19 survivors, who represent the majority of the general population.

Optimizing lifestyle profiles is potential for preventing nonalcoholic fatty liver disease and enhancing its survival

The aim of this study was to evaluate the association between lifestyle profile and disease incidence/mortality in patients with non-alcoholic fatty liver disease (NAFLD). Lifestyle profiles ascertainment was based on the latent profile analysis. The associations of lifestyle profile and outcomes were analyzed by multivariate logistic or Cox regressions. Four lifestyle profiles (profile 1 and 2 for male, profile 3 and 4 for female) were established for all participants. Compared to profile 1, profile 2 (P = 0.042) and profile 3 (P = 0.013) had lower incidence for NAFLD. In contrast, profile 4 showed similar NAFLD prevalence compared to profile 1 (P = 0.756). Individuals with NAFLD within profile 3 had the best long-term survival, and the HR was 0.55 (95% CI 0.40-0.76) for all-cause mortality (compared to profile 1). Profile 4 (P = 0.098) and profile 2 (P = 0.546) had similar all-cause survival compared to profile 1. We explored the associations of healthy lifestyle score with mortality and incidence of NAFLD stratified by lifestyle profiles. We observed that with the increase of healthy lifestyle score, participants within profile 2 did not display lower NAFLD incidence and better long-term survival in NAFLD cases. In this study, lifestyle profiles were constructed in NHANES participants. The distinct lifestyle profiles may help optimize decision-making regarding lifestyle management in preventing NAFLD development, as well as selection of a more personalized approach for improving NAFLD survival.

Developmental Programming: Impact of Prenatal Exposure to Bisphenol A on Senescence and Circadian Mediators in the Liver of Sheep

Prenatal exposure to endocrine disruptors such as bisphenol A (BPA) plays a critical role in the developmental programming of liver dysfunction that is characteristic of nonalcoholic fatty liver disease (NAFLD). Circadian and aging processes have been implicated in the pathogenesis of NAFLD. We hypothesized that the prenatal BPA-induced fatty-liver phenotype of female sheep is associated with premature hepatic senescence and disruption in circadian clock genes. The expression of circadian rhythm and aging-associated genes, along with other markers of senescence such as telomere length, mitochondrial DNA copy number, and lipofuscin accumulation, were evaluated in the liver tissue of control and prenatal BPA groups. Prenatal BPA exposure significantly elevated the expression of aging-associated genes GLB1 and CISD2 and induced large magnitude differences in the expression of other aging genes-APOE, HGF, KLOTHO, and the clock genes PER2 and CLOCK-in the liver; the other senescence markers remained unaffected. Prenatal BPA-programmed aging-related transcriptional changes in the liver may contribute to pathological changes in liver function, elucidating the involvement of aging genes in the pathogenesis of liver steatosis.

Distinct roles of telomerase activity in age-related chronic diseases: An update literature review

Although telomerase has low activity in somatic quiescent cells, it plays an significant roles in regenerative cells such as endothelial cells, hepatocytes, epithelial cells, and hemocytes. Telomerase activity and telomere length are critical factors in age-related chronic diseases as they are closely related to cell senescence. However, whether telomerase activity plays a key role in disease progression or whether the role of telomerase is unified among different diseases are unresolved. Considering that aging is the most important risk factor for neurodegenerative and metabolic diseases, this article will analyze the evidence, mechanism, and therapeutic potential of telomerase activity in several chronic disease, including type 2 diabetes, neurodegenerative diseases, atherosclerosis, heart failure and non-alcoholic fatty liver disease, in order to provide clues for the use of telomerase activity to target the treatment of age-related chronic diseases.

Causal relationships between telomere length and liver disease: a Mendelian randomization study

Background: Leukocyte telomere length and hepatic disorders have been linked in various research studies, although their causative association has not been clarified. This study investigated the causal relationship between the length of telomeres on peripheral blood leukocytes and certain liver disorders. Methods: Mendelian randomization (MR) analysis was used to examine the relationship between leukocyte telomere length and risk of liver disease using the publicly accessible worldwide gene-wide association study (GWAS) database. The weighted mode, weighted median, and inverse variance weighted (IVW) methods were employed as supplements to the IVW approach, which is the main analytical method. Results: Leukocytes with longer telomeres may have a lower risk of developing cirrhosis [OR = 0.645 (0.524, 0.795), p = 3.977E-05] and a higher chance of developing benign liver tumors [OR = 3.087 (1.721, 5.539), p = 1.567E-04]. There was no direct link between telomere length and fatty liver, hepatic fibrosis, or liver cancer. Our findings in the replication analysis agreed with those of the previous studies. Conclusion: Further research is needed to examine the mechanisms underlying the probable causal association between the length of leukocyte telomeres and cirrhosis and benign liver cancer.

Shorter leukocyte telomere length protects against NAFLD progression in children

Leukocyte telomere length (LTL) gets shorter with each cell division and is also sensitive to reactive oxygen species damage and inflammatory processes. Studies in adults with non-alcoholic fatty liver disease (NAFLD) have found that increased fibrosis but not ALT levels are associated with shorter LTL. Few pediatric studies have been conducted; as such, we sought to evaluate potential associations between LTL and liver disease and liver disease progression in pediatric patients. Using data from the Treatment of NAFLD in Children (TONIC) randomized controlled trial, we assessed the potential predictive relationship between LTL and liver disease progression based on two successive liver biopsies over 96 weeks. We assessed the potential relationship between LTL and child age, sex, and race/ethnicity and features of liver disease including components of histology. We subsequently evaluated predictors for improvement in non-alcoholic steatohepatitis (NASH) at 96 weeks including LTL. We also assessed predictors of lobular inflammation improvement at 96 weeks using multivariable models. Mean LTL at baseline was 1.33 ± 0.23 T/S. Increasing lobular and portal inflammation were associated with longer LTL. In multivariable models, greater lobular inflammation at baseline was associated with longer LTL (Coeff 0.03, 95% CI 0.006-0.13; p = 0.03). Longer LTL at baseline was associated with worsening lobular inflammation at 96 weeks (Coeff 2.41, 95% CI 0.78-4.04; p < 0.01). There was no association between liver fibrosis and LTL. The association between LTL and pediatric NASH does not parallel adults with no association between fibrosis stage and NASH. Conversely, longer LTL was associated with more lobular inflammation at baseline and increased lobular inflammation over the 96-week period. Longer LTL in children may indicate greater risk for future complications from NASH.

Association Between Physical Activity and Prevalence/Mortality of Non-Alcoholic Fatty Liver Disease in Different Socioeconomic Settings

Objectives: We aimed to investigate the effect of physical activity (PA) on non-alcoholic fatty liver disease (NAFLD) prevalence and long-term survival, particularly in some specific population such as those with different socioeconomic status (SES). Methods: Multivariate regression and interaction analyses were conducted to deal with confounders and interacting factors. Results: Active PA was associated with lower prevalence of NAFLD in both cohorts. Individuals with active-PA had better long-term survival compared to those with inactive-PA in both cohorts, and the results were only statistically significant in NAFLD defined by US fatty liver index (USFLI). We found clear evidence that the beneficial role of PA was more obvious in individuals with better SES, and the statistical significances were presented in both two hepatic steatosis index (HSI)-NAFLD cohorts from the NHANES III and NHANES 1999-2014. Results were consistent in all sensitivity analyses. Conclusion: We demonstrated the importance of PA in decrease the prevalence and mortality of NAFLD, and highlights the need for improving SES simultaneously to increase the protective effect of PA.

Non-alcoholic Fatty Liver Disease and Liver Fibrosis during Aging

Non-alcoholic fatty liver disease (NAFLD) and its progressive form non-alcoholic steatohepatitis (NASH) have emerged as the leading causes of chronic liver disease-related mortality. The prevalence of NAFLD/NASH is expected to increase given the epidemics of obesity and type 2 diabetes mellitus. Older patients are disproportionally affected by NASH and related complications such as progressive fibrosis, cirrhosis and hepatocellular carcinoma; however, they are often ineligible for liver transplantation due to their frailty and comorbidities, and effective medical treatments are still lacking. In this review we focused on pathways that are key to the aging process in the liver and perpetuate NAFLD/NASH, leading to fibrosis. In addition, we highlighted recent findings and cross-talks of normal and/or senescent liver cells, dysregulated nutrient sensing, proteostasis and mitochondrial dysfunction in the framework of changing metabolic milieu. Better understanding these pathways during preclinical and clinical studies will be essential to design novel and specific therapeutic strategies to treat NASH in the elderly.

Nonalcoholic fatty liver disease and its prognosis associates with shorter leucocyte telomeres in a 21-year follow-up study

Leucocyte telomere length (LTL) has been associated with nonalcoholic fatty liver disease (NAFLD), but the evidence is imperfect. Furthermore, liver fibrosis has been shown to correlate with mortality and recent studies have also found associations with LTL and fibrosis suggesting that LTL may have additional prognostic value in liver diseases. Our objective was to study the association of LTL and NAFLD and evaluate the association of LTL in prognosis of NAFLD subjects. Study subjects (n = 847) were middle-aged hypertensive patients. All participants were evaluated for NAFLD and their LTL was measured at baseline. Outcomes were obtained from Finnish Causes-of-Death Register and the Care Register for Health Care in Statistics Finland to the end of 2014. An inverse association with NAFLD prevalence and LTL length was observed (p < .001 for trend). Shortest telomere tertile possessed statistically significantly more NAFLD subjects even with multivariate analysis (shortest vs. middle tertile HR 1.98 p = .006 and shortest vs. longest tertile HR 2.03 p = .007). For the study period, mortality of the study group showed statistically significant relation with telomere length in univariate but not for multivariate analysis. In subgroup analysis, LTL did not associate with prognosis of non-NAFLD subjects. However, LTL was inversely associated with overall mortality in the subjects with NAFLD in both univariate (HR 0.16 p = .007) and multivariate analysis (HR 0.20 p = .045). In middle-aged Caucasian cohort, shorter leucocyte telomeres associated independently with increased prevalence of NAFLD. Shorter LTL was not associated with mortality in non-NAFLD patients whereas it predicted mortality of NAFLD patients independently.

PinX1 Depletion Improves Liver Injury in a Mouse Model of Nonalcoholic Fatty Liver Disease via Increasing Telomerase Activity and Inhibiting Apoptosis

PIN2/TRF1-interacting telomerase inhibitor 1 (PinX1) can inhibit tumor growth by inhibiting telomerase activity. However, only few studies investigated the expression and function of PinX1 in nonalcoholic fatty liver disease (NAFLD). Thus, here we aimed to explore the roles of PinX1 in high-fat diet (HFD)-induced NAFLD in mice and in isolated hepatocytes. The mRNA expression of PinX1 and mTERT as well as telomere length were analyzed by RT-PCR. Pathological changes were detected by HE staining and oil red O staining. Triglyceride, cholesterol, alanine aminotransferase, aspartic aminotransferase, and telomerase activity were detected by ELISA. Hepatocyte apoptosis was determined by TUNEL and flow cytometry, and protein expression was analyzed by western blotting. We found that the expression of PinX1 was upregulated in the HFD group compared with the WT group. PinX1 knockout improved HFD-induced liver injury in mice and exhibited less lipid accumulation in hepatocytes. Moreover, telomere length, telomerase activity, and mTERT expression were significantly reduced in liver tissues of HFD-induced mice and palmitic acid-induced hepatocytes, while PinX1 knockout attenuated the effect. Furthermore, HFD-induced PinX1-/- mice exhibited less hepatocyte apoptosis than HFD-induced WT mice. Besides, PinX1 knockout inhibited the increase of cleaved caspase-3 and cleaved PARP expression in vivo and in vitro. Moreover, inhibition of mTERT reversed the effect of PinX1 knockout in hepatocytes. Taken together, our findings indicate that PinX1 promotes hepatocyte apoptosis and lipid accumulation by decreasing telomere length and telomerase activity in the development of NAFLD. PinX1 might be a target for the treatment of NAFLD.

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.

Association between telomere length and hepatic fibrosis in non-alcoholic fatty liver disease

Telomere length has been linked to the prevalence and progression of metabolic disease. However, clinical implications of telomere length in biopsy-proven non-alcoholic fatty liver disease (NAFLD) patients remain unclear. Therefore, this study aimed to investigate the association of telomere length with the histological severity of NAFLD. The cross-sectional data derived from the prospectively enrolled Boramae NAFLD registry (n = 91) were analyzed. The liver tissues and clinical information were obtained from both NAFLD patients and non-NAFLD subjects. Binary logistic regression was performed to identify the independent association between telomere length and the histological severity of NAFLD. A total of 83 subjects with or without biopsy-proven NAFLD were included for analysis: non-NAFLD in 23 (27.7%), non-alcoholic fatty liver in 15 (18.1%), and non-alcoholic steatohepatitis (NASH) in 45 (54.2%). Telomere length measured from liver tissues showed a strong negative correlation (p < 0.001) with age, regardless of NAFLD status. Therefore, telomere length was corrected for age. Age-adjusted telomere length than decreased gradually with an increasing severity of fibrosis in patients with NAFLD (p < 0.028). In multivariate analysis, age-adjusted telomere length (odds ratio [OR] 0.59; 95% CI 0.37–0.92; p = 0.019) and high-density lipoprotein cholesterol (OR 0.94; 95% CI 0.80–0.99; p = 0.039) were independently associated with significant fibrosis. The age-adjusted telomere length tends to decrease along with the fibrosis stage of NAFLD. In particular, among the histological components of NAFLD, fibrosis severity seems to be related to telomere length in the liver.

Inverse Association of Telomere Length With Liver Disease and Mortality in the US Population

Physiologic aging leads to attrition of telomeres and replicative senescence. An acceleration of this process has been hypothesized in the progression of chronic liver disease. We sought to examine the association of telomere length (TL) with liver disease and its impact on mortality risk. A cohort of 7,072 adults with leukocyte TL measurements from the National Health and Nutrition Examination Survey 1999‐2002 with mortality follow‐up through 2015 was analyzed. Liver disease was defined by aminotransferase levels and classified into etiology‐based and advanced fibrosis categories. Multivariable‐adjusted linear regression models estimated effect sizes, with 95% confidence intervals (CIs), of the presence of liver disease on TL. Cox regression models evaluated associations between TL and all‐cause mortality risk using adjusted hazard ratios (HRs). The cohort was representative of the US population with mean age 46.1 years and mean TL 5.79 kilobase pairs. No overall association between TL and liver disease was found; however, there was a significant negative association of TL and advanced liver fibrosis in individuals aged 65 and above. The liver disease cohort (HR 1.22, 95% CI 0.99‐1.51) and those with metabolic syndrome (HR 1.26, 95% CI 0.96‐1.67) had increased mortality risk with shorter TL. The relationship between TL and all‐cause mortality was stronger in women (HR 1.51, 95% CI 1.02‐2.23) and in non‐Hispanic Whites (HR 1.37, 95% CI 1.02‐1.84). Conclusion: Shortened leukocyte TL is independently associated with advanced liver disease at older ages, and with a higher risk of all‐cause mortality in those with liver disease. These associations reaffirm the need to better understand the role of telomeres in the progression of liver disease.

Telomerase: a key player in the pathogenesis of non-alcoholic fatty liver disease?

Introduction: Telomerase is a basic nuclear protein reverse transcriptase, which plays a key role in maintaining telomere stability, genome integrity, long-term cell activity, and potential continued proliferation.Area covered: This narrative review discusses key research advances involving telomerase in the development and progression of nonalcoholic fatty liver disease (NAFLD). The review evaluates 9a) whether the assessment of telomerase can be used as a noninvasive diagnostic tool; and (b) whether modification of telomerase function might be a useful potential therapeutic target for treatment of NAFLD. Furthermore, the relationship between telomerase and other chronic metabolic diseases is evaluated.Expert opinion: Several experimental and preclinical studies have suggested that telomerase plays an important role in the development of NAFLD. However, further mechanistic studies are needed to prove a causal relationship and to better elucidate whether the measurement of telomerase has utility as a diagnostic tool or whether pharmacological manipulation of telomerase has therapeutic potential in NAFLD treatment.

Genetically determined hypercholesterolaemia results into premature leucocyte telomere length shortening and reduced haematopoietic precursors

AIMS

Leucocyte telomere length (LTL) shortening is a marker of cellular senescence and associates with increased risk of cardiovascular disease (CVD). A number of cardiovascular risk factors affect LTL, but the correlation between elevated LDL cholesterol (LDL-C) and shorter LTL is debated: in small cohorts including subjects with a clinical diagnosis of familial hypercholesterolaemia (FH). We assessed the relationship between LDL-C and LTL in subjects with genetic familial hypercholesterolaemia (HeFH) compared to those with clinically diagnosed, but not genetically confirmed FH (CD-FH), and normocholesterolaemic subjects.

METHODS AND RESULTS

LTL was measured in mononuclear cells-derived genomic DNA from 206 hypercholesterolaemic subjects (135 HeFH and 71 CD-FH) and 272 controls. HeFH presented shorter LTL vs. controls (1.27 ± 0.07 vs. 1.59 ± 0.04, P = 0.045). In particular, we found shorter LTL in young HeFH as compared to young controls (<35 y) (1.34 ± 0.08 vs. 1.64 ± 0.08, P = 0.019); moreover, LTL was shorter in statin-naïve HeFH subjects as compared to controls (1.23 ± 0.08 vs. 1.58 ± 0.04, P = 0.001). HeFH subjects presented shorter LTL compared to LDL-C matched CD-FH (1.33 ± 0.05 vs. 1.55 ± 0.08, P = 0.029). Shorter LTL was confirmed in leucocytes of LDLR-KO vs. wild-type mice and associated with lower abundance of long-term haematopoietic stem and progenitor cells (LT-HSPCs) in the bone marrow. Accordingly, HeFH subjects presented lower circulating haematopoietic precursors (CD34 + CD45dim cells) vs. CD-FH and controls.

CONCLUSIONS

We found (i) shorter LTL in genetically determined hypercholesterolaemia, (ii) lower circulating haematopoietic precursors in HeFH subjects, and reduced bone marrow resident LT-HSPCs in LDLR-KO mice. We support early cellular senescence and haematopoietic alterations in subjects with FH.

Short Telomeres: Cause and Consequence in Liver Disease

Short telomere syndrome is a genetically inherited syndrome resulting in premature telomere shortening. This premature shortening of telomeres can result in hematologic, pulmonary, vascular, gastrointestinal, and hepatic manifestations of disease. Identifying patients with short telomere syndrome can be a clinical challenge due to the multitude of potential manifestations and lack of widely available diagnostic tests. In this review, we will highlight hepatic manifestations of short telomere syndrome with a focus on diagnosis, testing, and potential treatments.

Association of leukocyte telomere length with non-alcoholic fatty liver disease in patients with type 2 diabetes

Background:

Leukocyte telomere has been shown to be related to insulin resistance-related diseases, such as type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD). This cross-sectional study investigated the association of leukocyte telomere length (LTL) with NAFLD in T2DM patients.

Methods:

Clinical features were collected and LTL was measured by Southern blot-based terminal restriction fragment length analysis in 120 T2DM patients without NAFLD and 120 age-matched T2DM patients with NAFLD. NAFLD was clinically defined by manifestations of ultrasonography. The correlation between LTL and clinical and biochemical parameters were analyzed by Pearson correlation or Spearman correlation analysis. Factors for NAFLD in T2DM patients were identified using multiple logistic regressions.

Results:

LTL in T2DM patients with NAFLD were significantly longer than those without NAFLD (6400.2 ± 71.8 base pairs [bp] vs. 6023.7 ± 49.5 bp, P < 0.001), especially when diabetes duration was less than 2 years. Meanwhile, the trend of shorter LTL was associated with the increased diabetes duration in T2DM patient with NAFLD, but not in T2DM patients without NAFLD. Finally, LTL (odds ratio [OR]: 1.001, 95% confidence interval [CI]: 1.000–1.002, P = 0.001), as well as body mass index (OR: 1.314, 95% CI: 1.169–1.477, P < 0.001) and triglycerides (OR: 1.984, 95% CI: 1.432–2.747, P < 0.001), had a significant association with NAFLD status in T2DM patients.

Conclusions:

T2DM patients with NAFLD had a significantly longer LTL than those without NAFLD. The longer LTL was especially evident in the early stage of T2DM, indicating that longer LTL may be used as a biomarker for NAFLD in T2DM patients.

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.

Shorter leucocyte telomere length as a potential biomarker for nonalcoholic fatty liver disease-related advanced fibrosis in T2DM patients

Background

Telomere length has been linked to hepatic fibrosis. Type 2 diabetes mellitus (T2DM) is considered as a particular risk for the development of hepatic fibrosis. This study is to explore the association of leucocyte telomere length (LTL) and nonalcoholic fatty liver disease (NAFLD)-related advanced fibrosis in T2DM patients.

Methods

A total of 442 patients with T2DM were enrolled from Tongji Hospital, Wuhan, China. Clinical features were collected and LTL was measured by Southern blot-based terminal restriction fragment length. Hepatic advanced fibrosis was determined by both the NAFLD fibrosis score (NFS) and fibrosis-4 score (FIB-4). Explanatory factors for advanced fibrosis in T2DM patients were identified using multiple logistic regressions.

Results

T2DM patients with advanced fibrosis had significant shorter LTL than the no-advanced group. Additionally, LTL, age, male and aminotransferase (ALT) were significantly associated with advanced fibrosis status in T2DM patients. Longer diabetes duration was found to have a strong association with advanced fibrosis in elder T2DM patients.

Conclusions

Shorter LTL was significantly associated with advanced fibrosis in T2DM patients. Longer diabetes duration was an independent risk factor for advanced fibrosis in old T2DM patients. Shorter LTL may be used as a biomarker for advanced fibrosis in T2DM patients.

Telomere shortening: An innocent bystander at the crossroad of NASH with ageing and cardiometabolic risk?

See Article on Page 1839

Association between cagA negative Helicobacter pylori status and nonalcoholic fatty liver disease among adults in the United States

We investigated the relationship of H. pylori stratified by cytotoxin-associated gene A (cagA) status with nonalcoholic fatty liver disease (NAFLD) in the general population of the United States (US). We utilized the Third National Health and Nutrition Examination Survey from 1988 to 1994 in this study. NAFLD was defined by ultrasonographic detection of hepatic steatosis in the absence of other known causes of liver diseases and significant alcohol consumption. Hepatic steatosis was assessed by parenchymal brightness, liver to kidney contrast, deep beam attenuation, bright vessel walls and gallbladder wall definition. Antibodies to H. pylori and cagA of participants were measured using H. pylori IgG and anti-cagA IgG enzyme-linked immunosorbent assays. Among 5,404 participants, the prevalence of NAFLD was higher in H. pylori positive subjects (33.5±1.8%) compared to H. pylori negative subjects (26.1±1.7%, p <0.001). In terms of cagA protein status stratification, while cagA positive H. pylori group did not demonstrate an association with NAFLD (OR: 1.05; 95% CI: 0.81-1.37), cagA negative H. pylori group was noted to have a significant association with NAFLD in a multivariable analysis (OR: 1.30; 95% CI: 1.01-1.67). In conclusion, our study demonstrated that cagA negative H. pylori infection was an independent predictor of NAFLD in the US general population.