NAFLD VS MAFLD. The evidence-based debate has come. Time to change?

Shining a spotlight on sarcopenia and myosteatosis in liver disease and liver transplantation: Potentially modifiable risk factors with major clinical impact

Muscle-wasting and disease-related malnutrition are highly prevalent in patients with chronic liver diseases (CLD) as well as in liver transplant (LT) candidates. Alterations of body composition (BC) such as sarcopenia, myosteatosis and sarcopenic obesity and associated clinical frailty were tied to inferior clinical outcomes including hospital admissions, length of stay, complications, mortality and healthcare costs in various patient cohorts and clinical scenarios. In contrast to other inherent detrimental individual characteristics often observed in these complex patients, such as comorbidities or genetic risk, alterations of the skeletal muscle and malnutrition are considered as potentially modifiable risk factors with a major clinical impact. Even so, there is only limited high-level evidence to show how these pathologies should be addressed in the clinical setting. This review discusses the current state-of-the-art on the role of BC assessment in clinical outcomes in the setting of CLD and LT focusing mainly on sarcopenia and myosteatosis. We focus on the disease-related pathophysiology of BC alterations. Based on these, we address potential therapeutic interventions including nutritional regimens, physical activity, hormone and targeted therapies. In addition to summarizing existing knowledge, this review highlights novel trends, and future perspectives and identifies persisting challenges in addressing BC pathologies in a holistic way, aiming to improve outcomes and quality of life of patients with CLD awaiting or undergoing LT.

Crosstalk interactions between transcription factors ERRα and PPARα assist PPARα-mediated gene expression

OBJECTIVE

The peroxisome proliferator-activated receptor α (PPARα) is a transcription factor driving target genes involved in fatty acid β-oxidation. To what extent various PPARα interacting proteins may assist its function as a transcription factor is incompletely understood. An ORFeome-wide unbiased mammalian protein-protein interaction trap (MAPPIT) using PPARα as bait revealed a PPARα-ligand-dependent interaction with the orphan nuclear receptor estrogen-related receptor α (ERRα). The goal of this study was to characterize the nature of the interaction in depth and to explore whether it was of physiological relevance.

METHODS

We used orthogonal protein-protein interaction assays and pharmacological inhibitors of ERRα in various systems to confirm a functional interaction and study the impact of crosstalk mechanisms. To characterize the interaction surfaces and contact points we applied a random mutagenesis screen and structural overlays. We pinpointed the extent of reciprocal ligand effects of both nuclear receptors via coregulator peptide recruitment assays. On PPARα targets revealed from a genome-wide transcriptome analysis, we performed an ERRα chromatin immunoprecipitation analysis on both fast and fed mouse livers.

RESULTS

Random mutagenesis scanning of PPARα's ligand-binding domain and coregulator profiling experiments supported the involvement of (a) bridging coregulator(s), while recapitulation of the interaction in vitro indicated the possibility of a trimeric interaction with RXRα. The PPARα·ERRα interaction depends on 3 C-terminal residues within helix 12 of ERRα and is strengthened by both PGC1α and serum deprivation. Pharmacological inhibition of ERRα decreased the interaction of ERRα to ligand-activated PPARα and revealed a transcriptome in line with enhanced mRNA expression of prototypical PPARα target genes, suggesting a role for ERRα as a transcriptional repressor. Strikingly, on other PPARα targets, including the isolated PDK4 enhancer, ERRα behaved oppositely. Chromatin immunoprecipitation analyses demonstrate a PPARα ligand-dependent ERRα recruitment onto chromatin at PPARα-binding regions, which is lost following ERRα inhibition in fed mouse livers.

CONCLUSIONS

Our data support the coexistence of multiple layers of transcriptional crosstalk mechanisms between PPARα and ERRα, which may serve to finetune the activity of PPARα as a nutrient-sensing transcription factor.

Multi-omics analysis of a fatty liver model using human hepatocyte chimeric mice

We developed a fatty liver mouse model using human hepatocyte chimeric mice. As transplanted human hepatocytes do not respond to mouse growth hormone (GH) and tend to accumulate fat, we hypothesized that addition of human GH would alter lipid metabolism and reduce accumulation of fat in the liver even when fed a high-fat diet. Six uPA/SCID chimeric mice were fed a high-fat GAN diet to induce fatty liver while six were fed a normal CRF1 diet, and GH was administered to three mice in each group. The mice were euthanized at 8 weeks, and human hepatocytes were extracted for RNA-Seq, DIA proteomics, and metabolomics analysis. Abdominal echocardiography revealed that the degree of fatty liver increased significantly in mice fed GAN diet (p < 0.001) and decreased significantly in mice treated with GH (p = 0.026). Weighted gene correlation network analysis identified IGF1 and SEMA7A as eigengenes. Administration of GH significantly reduced triglyceride levels and was strongly associated with metabolism of amino acids. MiBiOmics analysis identified perilipin-2 as a co-inertia driver. Results from multi-omics analysis revealed distinct gene expression and protein/metabolite profiles in each treatment group when mice were fed a high-fat or normal diet with or without administration of GH.

Performance Evaluation of a Novel Non-Invasive Test for the Detection of Advanced Liver Fibrosis in Metabolic Dysfunction-Associated Fatty Liver Disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) may progress to advanced liver fibrosis (ALF). We evaluated the diagnostic accuracy of a novel Liver Fibrosis Risk Index (LFRI) in MAFLD subjects using transient elastography (TE) as the reference method for liver fibrosis measurement and then the diagnostic performance of a new two-step non-invasive algorithm for the detection of ALF risk in MAFLD, using Fibrosis-4 (FIB-4) followed by LFRI and comparing it to the reference algorithm based on FIB-4 and TE. We conducted a prospective study on 104 MAFLD European adult subjects. All consenting subjects underwent TE and measurements of FIB-4 and LFRI. For FIB-4 and TE, validated cut-offs were used. An ROC analysis showed that LFRI diagnosed severe fibrosis with moderate accuracy in MAFLD subjects with a negative predictive value above 90%. Using the new algorithm with LFRI thresholds recommended by the manufacturer, the number of subjects classified into ALF risk groups (low, intermediate, or high) differed significantly when compared with the reference algorithm (p = 0.001), with moderate agreement between them (weighted kappa (95% CI) = 0.59 (0.41-0.77)). To improve the performance of the LFRI-based algorithm, we modified cut-off points based on ROC curves obtained by dividing the study population according to the reference algorithm and observed no difference between algorithms (p = 0.054) in categorizing ALF risk, with a slight increase in the total agreement (weighted kappa (95% CI) = 0.63 (0.44-0.82)). Our findings suggest that using the novel LFRI as a second-line test may represent a potential alternative for liver fibrosis risk stratification in MAFLD patients; however, modified cut-offs are needed to optimize its performance.

Nonalcoholic Fatty Liver Disease vs Metabolic-associated Fatty Liver Disease vs Metabolic Dysfunction-associated Steatotic Liver Disease: What's in the Name?

How to cite this article: Singh SP, Sudhamshu KC, Anirvan P, et al. Nonalcoholic Fatty Liver Disease vs Metabolic-associated Fatty Liver Disease vs Metabolic Dysfunction-associated Steatotic Liver Disease: What's in the Name? Euroasian J Hepato-Gastroenterol 2024;14(1):1-4.

Incidence of Metabolic Syndrome and Its Risk Factors in Elderly with Nonalcoholic Fatty Liver Disease

Purpose

This study aimed to determine the incidence of metabolic syndrome (MetS) and its predictors in older patients with nonalcoholic fatty liver disease.

Patients and Methods

This retrospective cohort study analyzed repeated health surveillance data collected between 2009 and 2018 at Mackay Memorial Hospital, Taiwan. MetS was defined based on the modified National Cholesterol Education Program Adult Treatment Panel III (Taiwan revision). Participants were diagnosed with fatty liver disease using abdominal ultrasonography. The exclusion criteria included age <65 years, having viral hepatitis, frequent alcohol consumption, and pre-existing MetS. Logistic regression analysis was conducted, adjusting for sex and age.

Results

We enrolled 758 older participants; 457 (60.3%) with preexisting metabolic syndrome were excluded. We studied the remaining 301 participants (39.7%), with a mean age of 71.3 ± 5.4 years. The cumulative incidence of MetS was 43.5% after a mean follow-up period of 4.2 years; moreover, it was higher in women as well as in participants with diabetes and hypertriglyceridemia. After adjusting for age and sex, we identified the following risk factors for MetS: baseline high fasting plasma glucose levels (adjusted odds ratio [aOR] =1.75; 95% confidence interval [CI] 1.03-2.95), baseline hypertriglyceridemia (aOR = 2.26; 95% CI 1.15-4.47), and baseline large waist circumference (aOR =1.71; 95% CI 1.01-2.89). Furthermore, increased waist circumference and fasting plasma glucose levels at follow-up were significant risk factors.

Conclusion

There is a high incidence of MetS among older individuals with nonalcoholic fatty liver disease; further, women and individuals with diabetes or hypertriglyceridemia are at risk of developing MetS. Moreover, waist circumference and fasting plasma glucose levels were positively associated with the risk of MetS.

Comparison between metabolic-associated fatty liver disease and nonalcoholic fatty liver disease: From nomenclature to clinical outcomes

As a result of the obesity epidemic, Nonalcoholic fatty liver disease (NAFLD) and its complications have increased among millions of people. Consequently, a group of experts recommended changing the term NAFLD to an inclusive terminology more reflective of the underlying pathogenesis; metabolic-associated fatty liver disease (MAFLD). This new term of MAFLD has its own disease epidemiology and clinical outcomes prompting efforts in studying its differences from NAFLD. This article discusses the rationale behind the nomenclature change, the main differences, and its clinical implications.

A Review of the Effects of Fucoxanthin on NAFLD

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease. Fucoxanthin, a red-orange marine carotenoid, is found in natural marine seaweeds with high antioxidant activity and several other remarkable biological features. The aim of this review is to gather evidence of the positive benefits of fucoxanthin on NAFLD. Fucoxanthin provides an extensive list of physiological and biological properties, such as hepatoprotective, anti-obesity, anti-tumor, and anti-diabetes properties, in addition to antioxidant and anti-inflammatory properties. This review focuses on published research on the preventative effects of fucoxanthin on NAFLD from the perspective of human clinical trials, animal experiments in vivo, and in vitro cell investigations. Using a variety of experimental designs, including treatment dosage, experiment model, and experimental periods, the positive effects of fucoxanthin were demonstrated. Fucoxanthin's biological activities were outlined, with an emphasis on its therapeutic efficacy in NAFLD. Fucoxanthin showed beneficial effects in modulating lipid metabolism, lipogenesis, fatty acid oxidation, adipogenesis, and oxidative stress on NAFLD. A deeper comprehension of NAFLD pathogenesis is essential for the development of novel and effective therapeutic strategies.

Development of LXR inverse agonists to treat MAFLD, NASH, and other metabolic diseases

Activation of LXR activity by synthetic agonists has been the focus of many drug discovery efforts with a focus on treatment of dyslipidemia and atherosclerosis. Many agonists have been developed, but all have been hindered due to their ability to efficaciously stimulate de novo lipogenesis. Here, we review the development of LXR inverse agonists that were originally optimized for their ability to enable recruitment of corepressors leading to silencing of genes that drive de novo lipogenesis. Such compounds have efficacy in animal models of MAFLD, dyslipidemia, and cancer. Several classes of LXR inverse agonists have been identified and one is now in clinical trials for treatment of severe dyslipidemia.