Relationship between Telomere Maintenance and Liver Disease

Development and validation of modified Liaoning score for predicting the prognosis of liver cirrhosis: a retrospective, international multicenter, observational study

BACKGROUND

Liaoning score has been developed and validated to predict the risk of esophageal varices in liver cirrhosis. This study aimed to further modify the Liaoning score by combining clinical and laboratory parameters to predict the long-term outcome of cirrhotic patients.

METHODS

First, 474 cirrhotic patients were retrospectively enrolled from Shenyang, China as the training cohort. Independent predictors for death were identified by competing risk analyses, and then a new prognostic model, called as modified Liaoning score, was developed. Its performance was externally validated at three centers from Fuzhou, China (n = 1944), Jinan, China (n = 485), and São Paulo, Brazil (n = 221).

RESULTS

Age, total bilirubin (TBIL), albumin (ALB), serum creatinine (SCr), and Liaoning score were independently associated with death in the training cohort. Modified Liaoning score = 0.159×Liaoning score + 0.010×TBIL(µmol/L)+0.029×age(years)+0.011×SCr(µmol/L)-0.037×ALB(g/L). The area under curve of modified Liaoning score was 0.714 (95%CI = 0.655-0.773), which was higher than that of Child-Pugh score (0.707, 95%CI = 0.645-0.770), MELD score (0.687, 95%CI = 0.623-0.751), and Liaoning score (0.583, 95%CI = 0.513-0.654). A modified Liaoning score of ≥ 1.296 suggested a higher cumulative incidence of death in liver cirrhosis (p < 0.001). Modified Liaoning score still had the highest prognostic performance in Chinese and Brazilian validation cohorts.

CONCLUSIONS

Modified Liaoning score can be considered for predicting the long-term outcome of cirrhotic patients.

Immune microenvironment changes of liver cirrhosis: emerging role of mesenchymal stromal cells

Cirrhosis is a progressive and diffuse liver disease characterized by liver tissue fibrosis and impaired liver function. This condition is brought about by several factors, including chronic hepatitis, hepatic steatosis, alcohol abuse, and other immunological injuries. The pathogenesis of liver cirrhosis is a complex process that involves the interaction of various immune cells and cytokines, which work together to create the hepatic homeostasis imbalance in the liver. Some studies have indicated that alterations in the immune microenvironment of liver cirrhosis are closely linked to the development and prognosis of the disease. The noteworthy function of mesenchymal stem cells and their paracrine secretion lies in their ability to promote the production of cytokines, which in turn enhance the self-repairing capabilities of tissues. The objective of this review is to provide a summary of the alterations in liver homeostasis and to discuss intercellular communication within the organ. Recent research on MSCs is yielding a blueprint for cell typing and biomarker immunoregulation. Hopefully, as MSCs researches continue to progress, novel therapeutic approaches will emerge to address cirrhosis.

Overview of CircRNAs Roles and Mechanisms in Liver Fibrosis

Liver fibrosis represents the reversible pathological process with the feature of the over-accumulation of extracellular matrix (ECM) proteins within the liver, which results in the deposition of fibrotic tissues and liver dysfunction. Circular noncoding RNAs (CircRNAs) have the characteristic closed loop structures, which show high resistance to exonuclease RNase, making them far more stable and recalcitrant against degradation. CircRNAs increase target gene levels by playing the role of a microRNA (miRNA) sponge. Further, they combine with proteins or play the role of RNA scaffolds or translate proteins to modulate different biological processes. Recent studies have indicated that CircRNAs play an important role in the occurrence and progression of liver fibrosis and may be the potential diagnostic and prognostic markers for liver fibrosis. This review summarizes the CircRNAs roles and explores their underlying mechanisms, with a special focus on some of the latest research into key CircRNAs related to regulating liver fibrosis. Results in this work may inspire fruitful research directions and applications of CircRNAs in the management of liver fibrosis. Additionally, our findings lay a critical theoretical foundation for applying CircRNAs in diagnosing and treating liver fibrosis.

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.

Cerium oxide nanoparticles administration during machine perfusion of discarded human livers: A pilot study

The combined approach of ex situ normothermic machine perfusion (NMP) and nanotechnology represents a strategy to mitigate ischemia/reperfusion injury in liver transplantation (LT). We evaluated the uptake, distribution, and efficacy of antioxidant cerium oxide nanoparticles (nanoceria) during normothermic perfusion of discarded human livers. A total of 9 discarded human liver grafts were randomized in 2 groups and underwent 4 h of NMP: 5 grafts were treated with nanoceria conjugated with albumin (Alb-NC; 50 µg/ml) and compared with 4 untreated grafts. The intracellular uptake of nanoceria was analyzed by electron microscopy (EM) and inductively coupled plasma-mass spectrometry (ICP-MS). The antioxidant activity of Alb-NC was assayed in liver biopsies by glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) assay, telomere length, and 4977-bp common mitochondrial DNA deletion (mtDNA⁴⁹⁷⁷ deletion). The cytokine profile was evaluated in perfusate samples. EM and ICP-MS confirmed Alb-NC internalization, rescue of mitochondrial phenotype, decrease of lipid droplet peroxidation, and lipofuscin granules in the treated grafts. Alb-NC exerted an antioxidant activity by increasing GSH levels (percentage change: +94% ± 25%; p = 0.01), SOD (+17% ± 4%; p = 0.02), and CAT activity (51% ± 23%; p = 0.03), reducing the occurrence of mtDNA⁴⁹⁷⁷ deletion (-67.2% ± 11%; p = 0.03), but did not affect cytokine release. Alb-NC during ex situ perfusion decreased oxidative stress, upregulating graft antioxidant defense. They could be a tool to improve quality grafts during NMP and represent an antioxidant strategy aimed at protecting the graft against reperfusion injury during LT.

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.

Genome-wide association of individual vulnerability with alcohol-associated liver disease: A Korean genome and epidemiology study

BACKGROUND AND AIMS

The quantity of alcohol leading to alcohol-associated liver disease (ALD) varies individually. Genetic backgrounds contributing to the divergence in individual susceptibility to alcohol-induced liver damage have not been elucidated in detail.

APPROACH AND RESULTS

Based on the Korean Genome and Epidemiology Study Health Examination (KoGES_HEXA) cohort data, 21,919 participants (40-79 years old) were included and divided into cases and controls based on the ALD diagnostic criteria proposed by the American College of Gastroenterology. Data generated by a genome wide-association study were analyzed using logistic regression to assess the risk of ALD development in nondrinkers, light drinkers, and heavy drinkers. We detected three loci, gamma-glutamyltransferase 1 (GGT1), zinc protein finger 827 (ZNF827) and HNF1 homeobox A (HNF1A), which were significantly associated with ALD risk. The GGT1 rs2006227 minor allele was strongly associated with all groups. Among the minor alleles of single nucleotide polymorphisms (SNPs) in HNF1A, rs1183910 had the strongest association with a protective effect from ALD in light drinkers. However, this association was not observed in heavy drinkers. Five SNPs on chromosome 11 showed suggestive significance in protective effects against ALD.

CONCLUSIONS

SNPs, including HNF1A rs1183910 minor allele, are the most promising genetic candidates for protection against ALD. The expression of genes contributing to ALD development may be altered by the amount of alcohol consumed.

Leukocyte Telomere Length Predicts Progression From Paroxysmal to Persistent Atrial Fibrillation in the Long Term After Catheter Ablation

Background

Aging is significantly associated with the incidence and progression of atrial fibrillation (AF) incidence. This study aimed to evaluate the potential predictive value of leukocyte telomere length (LTL) for progression from paroxysmal AF (PAF) to persistent AF (PsAF) after catheter ablation.

Methods and Results

A total of 269 patients with AF (154 patients with PAF and 115 patients with PsAF, respectively) were prospectively enrolled, and all patients with PAF at baseline were regularly followed up to determine whether and when they should progress to PsAF after catheter ablation therapy. Baseline relative LTL was measured by quantitative real-time PCR (rt-PCT). There was a significant negative association between LTL and age (r = −0.23, p < 0.001). Patients with PsAF had significantly shorter LTL than those with PAF. After a mean follow-up of 854.9 ± 18.7 d, progression events occurred in 35 out of the 154 patients with PAF. Those progressed patients with PAF were older (70.9 ± 8.0 vs. 62.3 ± 10.3, p < 0.001) and had shorter LTL (1.2 ± 0.3 vs. 1.5 ± 0.3, p < 0.001) than those who did not. The receiver operating characteristic (ROC) curve analysis showed a significant value of LTL in distinguishing patients with PAF from patients with PsAF, with an area under the ROC curve (AUC) of 0.63 (95% CI 0.56–0.70, p < 0.001), and the optimal cut-off value of LTL was 1.175, with a sensitivity and specificity of 56.03 and 82.04%, respectively. All patients with PAF were divided into two subgroups according to the optimal cut-off point of LTL calculated by the ROC curve analysis: high LTL group (≥1.175) and low LTL group (<1.175). Kaplan-Meier curve analysis showed that PAF patients with shorter LTL had a significantly higher rate of progression after catheter ablation (40.5% vs. 18.8%, log-rank test p < 0.001). Multivariate Cox proportional-hazards model indicated that LTL [hazard ratio (HR): 2.71, 95% CI 1.36–5.42, p = 0.005] was an independent predictor for progression from PAF to PsAF after catheter ablation therapy, but HATCH score was not (HR: 1.02, 95% CI: 0.68–1.52, p = 0.923).

Conclusion

Leukocyte telomere length was significantly associated with AF types. LTL was independently associated with progression from PAF to PsAF after catheter ablation therapy.

Chinese Clinical Trial Registry, Registration Number: ChiCTR1900021341.

The role of mitochondria dysfunction and hepatic senescence in NAFLD development and progression

Senescence is a crucial player in several metabolic disorders and chronic inflammatory diseases. Recent data prove the involvement of hepatocyte senescence in the development of NAFLD (non-alcoholic fatty liver disease). As the main energy and ROS (reactive oxygen species) producing organelle, mitochondria play the central role in accelerated senescence and diseases development. In this review, we focus on the role of regulation of mitochondrial Ca²⁺ homeostasis, NAD+/NADH ratio, UPR^mt (mitochondrial unfolded protein response), phospholipids and fatty acid oxidation in hepatic senescence, lifespan and NAFLD disease susceptibility. Additionally, the involvement of mitochondrial and nuclear mutations in lifespan-modulation and NAFLD development is discussed. While nuclear and mitochondria DNA mutations and SNPs (single nucleotide polymorphisms) can be used as effective diagnostic markers and targets for treatments, advanced age should be considered as an independent risk factor for NAFLD development.

Circular RNA as An Epigenetic Regulator in Chronic Liver Diseases

Circular RNA (circRNA) is a type of non-coding RNA characterized by a covalently closed continuous loop. CircRNA is generated by pre-mRNA through back-splicing and is probably cleared up by extracellular vesicles. CircRNAs play a pivotal role in the epigenetic regulation of gene expression at transcriptional and post-transcriptional levels. Recently, circRNAs have been demonstrated to be involved in the regulation of liver homeostasis and diseases. However, the epigenetic role and underlying mechanisms of circRNAs in chronic liver diseases remain unclear. This review discussed the role of circRNAs in non-neoplastic chronic liver diseases, including alcoholic liver disease (ALD), metabolic-associated fatty liver disease (MAFLD), viral hepatitis, liver injury and regeneration, liver cirrhosis, and autoimmune liver disease. The review also highlighted that further efforts are urgently needed to develop circRNAs as novel diagnostics and therapeutics for chronic liver diseases.

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.

The Dynamic Interplay Between Mast Cells, Aging/Cellular Senescence, and Liver Disease

Mast cells are key players in acute immune responses that are evidenced by degranulation leading to a heightened allergic response. Activation of mast cells can trigger a number of different pathways contributing to metabolic conditions and disease progression. Aging results in irreversible physiological changes affecting all organs, including the liver. The liver undergoes senescence, changes in protein expression, and cell signaling phenotypes during aging, which regulate disease progression. Cellular senescence contributes to the age-related changes. Unsurprisingly, mast cells also undergo age-related changes in number, localization, and activation throughout their lifetime, which adversely affects the etiology and progression of many physiological conditions including liver diseases. In this review, we discuss the role of mast cells during aging, including features of aging (e.g., senescence) in the context of biliary diseases such as primary biliary cholangitis and primary sclerosing cholangitis and nonalcoholic fatty liver disease.

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.

hsa_circ_0004018 suppresses the progression of liver fibrosis through regulating the hsa-miR-660-3p/TEP1 axis

Efforts have been made in the prevention and treatment of liver fibrosis. The inhibition or depletion of the hepatic stellate cells (HSCs) has been considered as a potential approach. Recently, there are numbers of studies about the role of the circular RNA in the disease progression. However, the role of circular RNA in the regulation of HSCs and the progression of liver fibrosis remained elusive. In this study, we constructed a CCl4-induced liver fibrosis mouse model and overexpressed hsa_circ_0004018 in HSCs. Then, salvianolic acid B was used to treat HSCs in vitro. We found that hsa_circ_0004018 is downregulated in liver fibrogenesis. Luciferase reporter assay was performed to verify the interaction of hsa_circ_0004018, hsa-miR-660-3p and TEP1. It showed that hsa_circ_0004018 may act as a sponge of hsa-miR-660-3p, which can target and downregulate the expression of TEP1. hsa_circ_0004018 expressing lentivirus was used to investigate the in-vivo function of hsa_circ_0004018 in CCl4-induced liver fibrosis mice. We also reveal that the hsa_circ_0004018/hsa-miR-660-3p/TEP1 axis contributes to the proliferation and activation of HSCs. In addition, the overexpression of hsa_circ_0004018 alleviated the progression of liver fibrosis. In conclusion, our study highlights hsa_circ_0004018 as a potential biomarker and therapeutic target for liver fibrosis.

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.

High Risk of Hepatocellular Carcinoma Development in Fibrotic Liver: Role of the Hippo-YAP/TAZ Signaling Pathway

Liver cancer is the fourth leading cause of cancer-related death globally, accounting for approximately 800,000 deaths annually. Hepatocellular carcinoma (HCC) is the most common type of liver cancer, making up about 80% of cases. Liver fibrosis and its end-stage disease, cirrhosis, are major risk factors for HCC. A fibrotic liver typically shows persistent hepatocyte death and compensatory regeneration, chronic inflammation, and an increase in reactive oxygen species, which collaboratively create a tumor-promoting microenvironment via inducing genetic alterations and chromosomal instability, and activating various oncogenic molecular signaling pathways. In this article, we review recent advances in fields of liver fibrosis and carcinogenesis, and consider several molecular signaling pathways that promote hepato-carcinogenesis under the microenvironment of liver fibrosis. In particular, we pay attention to emerging roles of the Hippo-YAP/TAZ signaling pathway in stromal activation, hepatic fibrosis, and liver cancer.