Fatty Liver through the Ages- Non-Alcoholic Steatohepatitis (NASH)

Management of Metabolic-Associated Fatty Liver Disease/Metabolic Dysfunction-Associated Steatotic Liver Disease: From Medication Therapy to Nutritional Interventions

Non-alcoholic fatty liver disease (NAFLD) is a common long-lasting liver disease that affects millions of people around the world. It is best identified with a hepatic fat build-up that ultimately leads to inflammation and damage. The classification and nomenclature of NAFLD have long been a controversial topic, until 2020 when a group of international experts recommended substituting NAFLD with MAFLD (metabolic dysfunction-associated FLD). MAFLD was then terminologically complemented in 2023 by altering it to MASLD, i.e., metabolic dysfunction-associated steatotic liver disease (MASLD). Both the MAFLD and the MASLD terminologies comprise the metabolic element of the disorder, as they offer diagnostic benchmarks that are embedded in the metabolic risk factors that underlie the disease. MASLD (as a multisystemic disease) provides a comprehensive definition that includes a larger population of patients who are at risk of liver morbidity and mortality, as well as adverse cardiovascular and diabetes outcomes. MASLD highlights metabolic risks in lean or normal weight individuals, a factor that has not been accentuated or discussed in previous guidelines. Novel antihyperglycemic agents, anti-hyperlipidemic drugs, lifestyle modifications, nutritional interventions, and exercise therapies have not been extensively studied in MAFLD and MASLD. Nutrition plays a vital role in managing both conditions, where centralizing on a diet rich in whole vegetables, fruits, foods, healthy fats, lean proteins, and specific nutrients (e.g., omega-3 fatty acids and fibers) can improve insulin resistance and reduce inflammation. Thus, it is essential to understand the role of nutrition in managing these conditions and to work with patients to develop an individualized plan for optimal health. This review discusses prevention strategies for NAFLD/MAFLD/MASLD management, with particular attention to nutrition and lifestyle correction.

FXR activation remodels hepatic and intestinal transcriptional landscapes in metabolic dysfunction-associated steatohepatitis

The escalating obesity epidemic and aging population have propelled metabolic dysfunction-associated steatohepatitis (MASH) to the forefront of public health concerns. The activation of FXR shows promise to combat MASH and its detrimental consequences. However, the specific alterations within the MASH-related transcriptional network remain elusive, hindering the development of more precise and effective therapeutic strategies. Through a comprehensive analysis of liver RNA-seq data from human and mouse MASH samples, we identified central perturbations within the MASH-associated transcriptional network, including disrupted cellular metabolism and mitochondrial function, decreased tissue repair capability, and increased inflammation and fibrosis. By employing integrated transcriptome profiling of diverse FXR agonists-treated mice, FXR liver-specific knockout mice, and open-source human datasets, we determined that hepatic FXR activation effectively ameliorated MASH by reversing the dysregulated metabolic and inflammatory networks implicated in MASH pathogenesis. This mitigation encompassed resolving fibrosis and reducing immune infiltration. By understanding the core regulatory network of FXR, which is directly correlated with disease severity and treatment response, we identified approximately one-third of the patients who could potentially benefit from FXR agonist therapy. A similar analysis involving intestinal RNA-seq data from FXR agonists-treated mice and FXR intestine-specific knockout mice revealed that intestinal FXR activation attenuates intestinal inflammation, and has promise in attenuating hepatic inflammation and fibrosis. Collectively, our study uncovers the intricate pathophysiological features of MASH at a transcriptional level and highlights the complex interplay between FXR activation and both MASH progression and regression. These findings contribute to precise drug development, utilization, and efficacy evaluation, ultimately aiming to improve patient outcomes.

Silymarin: Unveiling its pharmacological spectrum and therapeutic potential in liver diseases-A comprehensive narrative review

Liver diseases, encompassing conditions such as cirrhosis, present a substantial global health challenge with diverse etiologies, including viral infections, alcohol consumption, and non-alcoholic fatty liver disease (NAFLD). The exploration of natural compounds as therapeutic agents has gained traction, notably the herbal remedy milk thistle (Silybum marianum), with its active extract, silymarin, demonstrating remarkable antioxidant and hepatoprotective properties in extensive preclinical investigations. It can protect healthy liver cells or those that have not yet sustained permanent damage by reducing oxidative stress and mitigating cytotoxicity. Silymarin, a natural compound with antioxidant properties, anti-inflammatory effects, and antifibrotic activity, has shown potential in treating liver damage caused by alcohol, NAFLD, drug-induced toxicity, and viral hepatitis. Legalon® is a top-rated medication with excellent oral bioavailability, effective absorption, and therapeutic effectiveness. Its active component, silymarin, has antioxidant and hepatoprotective properties, Eurosil 85® also, a commercial product, has lipophilic properties enhanced by special formulation processes. Silymarin, during clinical trials, shows potential improvements in liver function, reduced mortality rates, and alleviation of symptoms across various liver disorders, with safety assessments showing low adverse effects. Overall, silymarin emerges as a promising natural compound with multifaceted hepatoprotective properties and therapeutic potential in liver diseases.

Compensated Advanced Chronic Liver Disease and Steatosis in Patients with Type 2 Diabetes as Assessed through Shear Wave Measurements and Attenuation Measurements

Patients with type 2 diabetes (T2D) are at risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD). We investigated the prevalence of compensated advanced chronic liver disease (cACLD) and steatosis in patients with T2D using the new non-invasive diagnostic methods of shear wave measurements (SWMs) and attenuation (ATT) measurements in comparison with those of vibration-controlled transient elastography (VCTE) and the controlled attenuation parameter (CAP), which served as the reference methods. Among 214 T2D patients, steatosis at any grade and cACLD were revealed in 134 (62.6%) and 19 (8.9%) patients, respectively. SWMs showed a high correlation with VCTE (Spearman's ρ = 0.641), whereas SWMs produced lower (mean of -0.7 kPa) liver stiffness measurements (LSMs) overall. At a LSM of >11.0 kPa (Youden), SWMs had an AUROC of 0.951 that was used to diagnose cACLD (defined as a LSM of >15 kPa through VCTE) with 84.2% sensitivity and 96.4% specificity. The performance of ATT measurements in diagnosing liver steatosis at any grade (defined as the CAP of ≥274 dB/m) was suboptimal (AUROC of 0.744 at the ATT measurement cut-off of >0.63 dB/cm/MHz (Youden) with 59% sensitivity and 81.2% specificity). In conclusion, the prevalence of liver steatosis and previously unrecognized cACLD in patients with T2D is high and SWMs appear to be a reliable diagnostic method for this purpose, whereas further investigation is needed to optimize the diagnostic performance of ATT measurements.

Genetic variation and elevated liver enzymes during childhood, adolescence and early adulthood

BACKGROUND

Genetic factors influence the risk of fatty liver disease (FLD) in adults. The aim of this study was to test if, and when, genetic risk factors known to affect FLD in adults begin to exert their deleterious effects during childhood, adolescence and early adulthood.

METHODS

We included up to 4018 British children and adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort. Three genetic variants known to associate robustly with FLD in adults (PNPLA3 rs738409, TM6SF2 rs58542926 and HSD17B13 rs72613567) were tested for association with plasma levels of alanine transaminase (ALT) and aspartate transaminase (AST) during childhood (mean age: 9.9 years), early adolescence (15.5 years), late adolescence (17.8 years), and early adulthood (24.5 years). We also tested the associations of a 17-variant score and whole-genome polygenic risk scores (PRS) derived from associations in adults with plasma ALT and AST at the same four time points. Associations with elastography-derived liver steatosis and fibrosis were tested in early adulthood.

RESULTS

Genetic risk factors for FLD (individually, combined into a 3-variant score, a 17-variant score and as a genome-wide PRS), were associated with higher liver enzymes, beginning in childhood and throughout adolescence and early adulthood. The ALT-increasing effects of the genetic risk variants became larger with increasing age. The ALT-PRS was associated with liver steatosis in early adulthood. No genetic associations with fibrosis were observed.

CONCLUSIONS

Genetic factors that promote FLD in adults associate with elevated liver enzymes already during childhood, and their effects get amplified with increasing age.

Farnesoid X receptor is an important target for the treatment of disorders of bile acid and fatty acid metabolism in mice with nonalcoholic fatty liver disease combined with cholestasis

BACKGROUND AND AIM

The prevalence of nonalcoholic fatty liver disease (NAFLD) has been rising globally. NAFLD patients combined with cholestasis have more obvious liver fibrosis, impaired bile acid (BA), and fatty acid (FA) metabolism and severer liver injury; however, its therapeutic options are limited, and the underlying metabolic mechanisms are understood. Here, we aimed to investigate the effects of farnesoid X receptor (FXR) on BA and FA metabolism in NAFLD combined with cholestasis and related signaling pathways.

METHODS

A mouse model of NAFLD combined with cholestasis was established by joint intervention with high-fat diet (HFD) and alpha-naphthylisothiocyanate. The effects of FXR on BA and FA metabolism were evaluated by serum biochemical analysis. Liver damage was identified by histopathology. The expression of nuclear hormone receptor, membrane receptor, FA transmembrane transporter, and BA transporter protein in mice were measured by western blot.

RESULTS

NAFLD mice combined with cholestasis developed more severe cholestasis and dysregulated BA and FA metabolism. Meanwhile, the expression of FXR protein was decreased in NAFLD mice combined with cholestasis compared to the controls. Fxr-/- mice showed liver injury. HFD aggravated the liver injury with decreased BSEP expression, increased expression of NTCP, LXRα, SREBP-1c, FAS, ACC1, and CD36, and significantly increased BA and FA accumulation.

CONCLUSION

All the results suggested that FXR plays a key role in both FA and BA metabolism in NAFLD combined with cholestasis and thus may be a potential target for the treatment of disorders of BA and FA metabolism in NAFLD combined with cholestasis.

Comparison of Pathway Referrals for Liver Fibrosis Risk Stratification Performed in Diabetology and Nutrition Clinics

Purpose

A systematic screening for the presence of nonalcoholic fatty liver disease (NAFLD)-related advanced fibrosis is currently recommended in patients with type 2 diabetes mellitus (T2DM) and obesity. However, real-world data of such liver fibrosis risk stratification pathway from diabetology and nutrition clinics towards hepatology clinics are scarce. Therefore, we compared data from two pathways with or without transient elastography (TE) performed in diabetology and nutrition clinics.

Patients and Methods

This is a retrospective study comparing the proportion of patients with intermediate/high risk of advanced fibrosis (AF) as defined by a liver stiffness measurement (LSM) ≥8kPa, among patients referred in hepatology from two diabetology-nutrition departments at Lyon University Hospital, France between November 1st 2018 to December 31st 2019.

Results

Among the two diabetology and nutrition departments using TE or not, 27.5% (62/225) versus 44.2% (126/285) were referred to hepatology, respectively. The pathway using TE in diabetology and nutrition referred to hepatology a higher proportion of patients with intermediate/high risk of AF compared to the pathway without TE: 77.4% versus 30.9%, p<0.001. In the pathway with TE, the odds of patients with intermediate/high risk of AF referred to hepatology was significantly higher: OR: 7.7, 95% CI: 3.6-16.7, p<0.001 after adjustment for age, sex and presence of obesity and T2D compared to the pathway without TE in diabetology and nutrition clinics. However, among the patients not referred, 29.4% had an intermediate/high risk of AF.

Conclusion

A pathway-referral using TE performed in diabetology and nutrition clinics, significantly improves the liver fibrosis risk stratification and avoids over-referral. However, collaboration between diabetologist, nutritionists and hepatologists is needed to avoid under-referral.

Research Priorities for Precision Medicine in NAFLD

NAFLD is a multisystem condition and the leading cause of chronic liver disease globally. There are no approved NAFLD-specific dugs. To advance in the prevention and treatment of NAFLD, there is a clear need to better understand the pathophysiology and genetic and environmental risk factors, identify subphenotypes, and develop personalized and precision medicine. In this review, we discuss the main NAFLD research priorities, with a particular focus on socioeconomic factors, interindividual variations, limitations of current NAFLD clinical trials, multidisciplinary models of care, and novel approaches in the management of patients with NAFLD.

Physicians' Use of Digital Health Interventions in the Management of Nonalcoholic Fatty Liver Disease

Globally, the use of digital health interventions (DHIs) is expanding, along with growing scientific evidence of their effectiveness. Given the high and increasing prevalence of noncommunicable liver disease, we surveyed 295 physicians across Spain about their knowledge, beliefs, attitudes, practices, and access with regard to DHIs for patient care and in particular for liver diseases, including nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. Physicians reported high familiarity with DHIs, although most had not recommended them in patient care. Addressing concerns, including limited available time, evidence of effectiveness, education, training, and access may contribute to an increased uptake of these technologies.

Pharmacological inhibition of CFTR attenuates nonalcoholic steatohepatitis (NASH) progression in mice

Nonalcoholic steatohepatitis (NASH) is considered a pivotal stage in nonalcoholic fatty liver disease (NAFLD) progression and increases the risk of end-stage liver diseases such as fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The etiology of NASH is multifactorial and identifying reliable molecular players has proven difficult. Presently, there are no approved drugs for NASH treatment, which has become a leading cause of liver transplants worldwide. Here, using public human transcriptomic NAFLD dataset, we uncover Cystic fibrosis transmembrane conductance receptor (CFTR) as a differentially expressed gene in the livers of human NASH patients. Similarly, murine Cftr expression was also found to be upregulated in two mouse models of diet-induced NASH. Furthermore, the pharmacological inhibition of CFTR significantly reduced NASH progression in mice and its overexpression aggravated lipotoxicity in human hepatic cells. These results, thus, underscore the involvement of murine Cftr in the pathogenesis of NASH and raise the intriguing possibility of its pharmacological inhibition in human NASH.

Nonalcoholic Fatty Liver Disease

Management of nonalcoholic fatty liver disease (NAFLD) is crucial for type 2 diabetes (T2D) remission because they are linked through the common pathophysiology of insulin resistance and lipotoxicity. One in three patients with T2D has nonalcoholic steatohepatitis leading to fibrosis, cirrhosis, and hepatocellular carcinoma. Noninvasive testing with imaging and/or serum biomarkers can assess the risk for advanced liver disease. A liver biopsy is only necessary in select patients where there is diagnostic doubt. Treatments for NAFLD parallel T2D remission strategies focusing on weight loss and managing comorbid conditions through lifestyle modification, antiobesity medications, and/or bariatric surgery, and T2D medications with proven efficacy.

Effect of an obesogenic high-fat and high-sucrose diet on hepatic gene expression signatures in male Collaborative Cross mice

Nonalcoholic fatty liver disease (NAFLD), the most prevalent chronic liver disease, is characterized by substantial variations in case-level severity. In this study, we used a genetically diverse Collaborative Cross (CC) mouse population model to analyze the global transcriptome and clarify the molecular mechanisms involved in hepatic fat accumulation that determine the level and severity of NAFLD. Twenty-four strains of male CC mice were maintained on a high-fat/high-sucrose (HF/HS) diet for 12 wk, and their hepatic gene expression profiles were determined by next-generation RNA sequencing. We found that the development of the nonalcoholic fatty liver (NAFL) phenotype in CC mice coincided with significant changes in the expression of hepatic genes at the population level, evidenced by the presence of 724 differentially expressed genes involved in lipid and carbohydrate metabolism, cell morphology, vitamin and mineral metabolism, energy production, and DNA replication, recombination, and repair. Importantly, expression of 68 of these genes strongly correlated with the extent of hepatic lipid accumulation in the overall population of HF/HS diet-fed male CC mice. Results of partial least squares (PLS) modeling showed that these derived hepatic gene expression signatures help to identify the individual mouse strains that are highly susceptible to the development of NAFLD induced by an HF/HS diet. These findings imply that gene expression profiling, combined with a PLS modeling approach, may be a useful tool to predict NAFLD severity in genetically diverse patient populations.NEW & NOTEWORTHY Feeding male Collaborative Cross mice an obesogenic diet allows modeling NAFLD at the population level. The development of NAFLD coincided with significant hepatic transcriptomic changes in this model. Genes (724) were differentially expressed and expression of 68 genes strongly correlated with the extent of hepatic lipid accumulation. Partial least squares modeling showed that derived hepatic gene expression signatures may help to identify individual mouse strains that are highly susceptible to the development of NAFLD.

The genetic background shapes the susceptibility to mitochondrial dysfunction and NASH progression

Non-alcoholic steatohepatitis (NASH) is a global health concern without treatment. The challenge in finding effective therapies is due to the lack of good mouse models and the complexity of the disease, characterized by gene-environment interactions. We tested the susceptibility of seven mouse strains to develop NASH. The severity of the clinical phenotypes observed varied widely across strains. PWK/PhJ mice were the most prone to develop hepatic inflammation and the only strain to progress to NASH with extensive fibrosis, while CAST/EiJ mice were completely resistant. Levels of mitochondrial transcripts and proteins as well as mitochondrial function were robustly reduced specifically in the liver of PWK/PhJ mice, suggesting a central role of mitochondrial dysfunction in NASH progression. Importantly, the NASH gene expression profile of PWK/PhJ mice had the highest overlap with the human NASH signature. Our study exposes the limitations of using a single mouse genetic background in metabolic studies and describes a novel NASH mouse model with features of the human NASH.

Forecasted 2040 global prevalence of nonalcoholic fatty liver disease using hierarchical bayesian approach

BACKGROUND/AIMS

Due to increases in obesity and type 2 diabetes, the prevalence of nonalcoholic fatty liver disease (NAFLD) has also been increasing. Current forecast models may not include non-obese NAFLD. Here, we used the Bayesian approach to forecast the prevalence of NAFLD through the year 2040.

METHODS

Prevalence data from 245 articles involving 2,699,627 persons were used with a hierarchical Bayesian approach to forecast the prevalence of NAFLD through 2040. Subgroup analyses were performed for age, gender, presence of metabolic syndrome, region, and smoking status. Sensitivity analysis was conducted for clinical setting and study quality.

RESULTS

The forecasted 2040 prevalence was 55.7%, a three-fold increase since 1990 and a 43.2% increase from the 2020 prevalence of 38.9%. The estimated average yearly increase since 2020 was 2.16%. For those aged <50 years and ≥50 years, the 2040 prevalence were not significantly different (56.7% vs. 61.5%, P=0.52). There was a significant difference in 2040 prevalence by sex (males: 60% vs. 50%) but the trend was steeper for females (annual percentage change: 2.5% vs. 1.5%, P=0.025). There was no difference in trends overtime by region (P=0.48). The increase rate was significantly higher in those without metabolic syndrome (3.8% vs. 0.84%, P=0.003) and smokers (1.4% vs. 1.1%, P=0.011). There was no difference by clinical/community setting (P=0.491) or study quality (P=0.85).

CONCLUSION

By 2040, over half the adult population is forecasted to have NAFLD. The largest increases are expected to occur in women, smokers, and those without metabolic syndrome. Intensified efforts are needed to raise awareness of NAFLD and to determine long-term solutions addressing the driving factors of the disease.

Genetics, epigenetics and transgenerational transmission of obesity in children

Sedentary lifestyle and consumption of high-calorie foods have caused a relentless increase of overweight and obesity prevalence at all ages. Its presently epidemic proportion is disquieting due to the tight relationship of obesity with metabolic syndrome and several other comorbidities which do call for urgent workarounds. The usual ineffectiveness of present therapies and failure of prevention campaigns triggered overtime a number of research studies which have unveiled some relevant aspects of obesity genetic and epigenetic inheritable profiles. These findings are revealing extremely precious mainly to serve as a likely extra arrow to allow the clinician's bow to achieve still hitherto unmet preventive goals. Evidence now exists that maternal obesity/overnutrition during pregnancy and lactation convincingly appears associated with several disorders in the offspring independently of the transmission of a purely genetic predisposition. Even the pre-conception direct exposure of either father or mother gametes to environmental factors can reprogram the epigenetic architecture of cells. Such phenomena lie behind the transfer of the obesity susceptibility to future generations through a mechanism of epigenetic inheritance. Moreover, a growing number of studies suggests that several environmental factors such as maternal malnutrition, hypoxia, and exposure to excess hormones and endocrine disruptors during pregnancy and the early postnatal period may play critical roles in programming childhood adipose tissue and obesity. A deeper understanding of how inherited genetics and epigenetics may generate an obesogenic environment at pediatric age might strengthen our knowledge about pathogenetic mechanisms and improve the clinical management of patients. Therefore, in this narrative review, we attempt to provide a general overview of the contribution of heritable genetic and epigenetic patterns to the obesity susceptibility in children, placing a particular emphasis on the mother-child dyad.