Diagnosis of non-alcoholic fatty liver disease (NAFLD).

Non-alcoholic fatty liver disease (NAFLD) increases risk of mortality from liver and cardiovascular disease (CVD) and is the major cause of hepatocellular carcinoma (HCC), which may develop without cirrhosis. NAFLD predicts type 2 diabetes, even independently of obesity. Globally, the prevalence of NAFLD averages 25% and is as common as the metabolic syndrome. The majority of patients with type 2 diabetes have NAFLD. The challenge for the diabetologist is to identify patients at risk of advanced liver disease and HCC. At a minimum, liver function tests (LFTs), despite being neither specific nor sensitive, should be performed in all patients with the metabolic syndrome or type 2 diabetes. Increases in LFTs, for which the updated reference values are lower (serum ALT ≈30 U/l in men and ≈20 U/l in women) than those hitherto used in many laboratories, should prompt assessment of fibrosis biomarkers and referral of individuals at risk to a NAFLD/hepatology clinic. Preferably, evaluation of NAFLD should be based on measurement of steatosis biomarkers or ultrasound if easily available. A large number of individuals carry the patatin-like phospholipase domain containing 3 (PNPLA3) I148M variant (30-50%) or the transmembrane 6 superfamily member 2 (TM6SF2) E167K variant (11-15%). These variants increase the risk of advanced liver disease and HCC but not of diabetes or CVD. Genotyping of selected patients for these variants is recommended. Many patients have 'double trouble', i.e. carry both a genetic risk factor and have the metabolic syndrome. Excess use of alcohol could be a cause of 'triple trouble', but such patients would be classified as having alcoholic fatty liver disease. This review summarises a presentation given at the symposium 'The liver in focus' at the 2015 annual meeting of the EASD. It is accompanied by two other reviews on topics from this symposium (by Kenneth Cusi, DOI: 10.1007/s00125-016-3952-1 , and by John Jones, DOI: 10.1007/s00125-016-3940-5 ) and a commentary by the Session Chair, Michael Roden (DOI: 10.1007/s00125-016-3911-x ).

Characterization and Pharmacological Validation of a Preclinical Model of NASH in Göttingen Minipigs.

Background: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, which is associated with features of metabolic syndrome. NAFLD may progress in a subset of patients into nonalcoholic steatohepatitis (NASH) with liver injury resulting ultimately in cirrhosis and potentially hepatocellular carcinoma. Today, there is no approved treatment for NASH due to, at least in part, the lack of preclinical models recapitulating features of human disease. Here, we report the development of a dietary model of NASH in the Göttingen minipig. Methods: First, we performed a longitudinal characterization of diet-induced NASH and fibrosis using biochemical, histological, and transcriptional analyses. We then evaluated the pharmacological response to Obeticholic acid (OCA) treatment for 8 weeks at 2.5mg/kg/d, a dose matching its active clinical exposure. Results: Serial histological examinations revealed a rapid installation of NASH driven by massive steatosis and inflammation, including evidence of ballooning. Furthermore, we found the progressive development of both perisinusoidal and portal fibrosis reaching fibrotic septa after 6 months of diet. Histological changes were mechanistically supported by well-defined gene signatures identified by RNA Seq analysis. While treatment with OCA was well tolerated throughout the study, it did not improve liver dysfunction nor NASH progression. By contrast, OCA treatment resulted in a significant reduction in diet-induced fibrosis in this model. Conclusions: These results, taken together, indicate that the diet-induced NASH in the Göttingen minipig recapitulates most of the features of human NASH and may be a model with improved translational value to prioritize drug candidates toward clinical development.

Lysosomal Acid Lipase Activity in Non-alcoholic Fatty Liver Disease as a Novel Diagnostic and Therapeutic Target: A Systematic Literature Review of Current Evidence and Future Directions.

Background and aim: Non-alcoholic fatty liver disease (NAFLD) presents with the accumulation of excessive intra-hepatic fat without significant alcohol intake. Multifactorial pathogenesis is reported to be involved. Reduced lysosomal acid lipase (LAL) activity is suggested as one of the novel-involved pathogenic mechanisms. This review summarizes the available evidence on the role of LAL activity in NAFLD pathogenesis. Methods: Four databases namely, PubMed/Medline, Science direct, Cochrane Library, and Google scholar were searched to identify relevant observational records evaluating the role of LAL activity in the pathogenesis of NAFLD. All studies were assessed for their quality by using Newcastle-Ottawa Scale or The Joanna Briggs Institute Critical Appraisal tools for cohort and cross-sectional studies, respectively. The estimates of LAL activity and other clinical outcomes were expressed as mean (SD) and number (%) as presented in the primary studies. Results: A total of nine good quality studies with 1711 patients with NAFLD and 877 controls from different groups (healthy volunteers, alcoholics, cryptogenic cirrhosis, and HCV-positive) were included. From the NAFLD group, 59.55% were males and the overall mean age ranged between the studies from 12.6 ± 8.5 months in pediatrics to 58.90 ± 13.82 years in adults. In the NAFLD group, the LAL activity varied from 0.53 ± 0.08 to 1.3 ± 0.70 (nmol/spot/hr) between the studies which was less than all control groups except cryptogenic cirrhosis patients (0.5 ± 0.15 nmol/spot/hr). Of the other outcomes of interest, ALT, AST, total cholesterol, triglyceride, and LDL cholesterol were found elevated in NAFLD patients than in controls. Conclusion: The current evidence suggests a potential correlation of reduced LAL activity with NAFLD pathogenesis according to its severity. Large-scale studies are recommended, more importantly in patients with NAFLD having no metabolic or genetic involvement. Further LAL can act as a new non-invasive diagnostic biomarker to identify that specific NAFLD subgroup.

Public Health Measures and Prevention of Alcohol-Associated Liver Disease.

Hazardous alcohol consumption causes approximately 4% of deaths globally, constituting one of the leading risk factors for the burden of the disease worldwide. Alcohol has several health consequences, such as alcohol-associated liver disease, hepatocellular carcinoma, nonliver neoplasms, physical injury, cardiac disease, and psychiatric disorders. Alcohol misuse significantly affects workforce productivity, with elevated direct and indirect economic costs. Due to the high impact of alcohol consumption on the population, public health has led to the development of a range of strategies to reduce its harmful effects. Regulatory public health policies (PHP) for alcohol can exist at the global, regional, international, national, or subnational levels. Effective strategies incorporate a multilevel, multicomponent approach, targeting multiple determinants of drinking and alcohol-related harms. The World Health Organization categorizes the PHP into eight categories: national plan to fight the harmful consequences of alcohol, national license and production and selling control, taxes control and pricing policies, limiting drinking age, restrictions on alcohol access, driving-related alcohol policies, control over advertising and promotion, and government monitoring systems. These policies are supported by evidence from different populations, demonstrating that determinants of alcohol use depend on several factors such as socioeconomic level, age, sex, ethnicity, production, availability, marketing, and others. Although most policies have a significant individual effect, a higher number of PHP are associated with a lower burden of disease due to alcohol. The excessive consequences of alcohol constitute a call for action, and clinicians should advocate for developing and implementing a new PHP on alcohol consumption.

Pathogenesis of Alcohol-Associated Liver Disease.

Excessive alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences. While chronic, heavy alcohol consumption causes structural damage and/or disrupts normal organ function in virtually every tissue of the body, the liver sustains the greatest damage. This is primarily because the liver is the first to see alcohol absorbed from the gastrointestinal tract via the portal circulation and second, because the liver is the principal site of ethanol metabolism. Alcohol-induced damage remains one of the most prevalent disorders of the liver and a leading cause of death or transplantation from liver disease. Despite extensive research on the pathophysiology of this disease, there are still no targeted therapies available. Given the multifactorial mechanisms for alcohol-associated liver disease pathogenesis, it is conceivable that a multitherapeutic regimen is needed to treat different stages in the spectrum of this disease.

Screening of Family Members of Nonalcoholic Fatty Liver Disease Patients can Detect Undiagnosed Nonalcoholic Fatty Liver Disease Among Them: Is There a Genetic Link?

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) has multifactorial origin. Genetic and environmental factors lead to the biology of this complex disorder. In this study, we screened parents of cases with NAFLD and compared them with parents of cases without NAFLD to see its familial aggregation and the role of patatin-like phospholipase domain containing 3 (PNPLA3). METHOD: It was a cross-sectional study. Parents of probands with NAFLD and without NAFLD were screened with abdominal sonography, anthropometry, blood tests, transient elastography, and PNPLA3 polymorphism. RESULTS: We had enrolled 303 individuals: 51 probands with NAFLD, 50 probands without NAFLD, and their 202 parents. Parents of the NAFLD group had significantly higher metabolic risk factors as compared with parents of the non-NAFLD group. They had a significantly higher rate of fatty liver (P = 0.0001), mean serum aspartate aminotransferase levels (P = 0.011), mean serum alanine aminotransferase levels (P = 0.001),raised fasting and postprandial blood sugar levels, lower mean platelets (P = 0.033) and serum albumin levels (P = 0.005), and higher mean liver stiffness (P = 0.001) on transient elastography.Frequency of PNPLA3 polymorphism within NAFLD group was higher compared to the non-NAFLD group (mutant GG-13.3 vs 3.3%). Similarly, parents of NAFLD group had mutant GG in 15 % versus 5% in parents of non-NAFLD group, (P = 0.105, odds ratio 6), though it was not statistically significant but may be relevant. In this study, offsprings of parents with nonalcoholic steatohepatitis were likely to have GG homozygous allele. A NAFLD16 score based on parent's parameters was calculated to predict the probability of NAFLD occurrence in an overweight obese individual. CONCLUSION: Screening of parents of individuals with NAFLD will help in the identification of undiagnosed NAFLD cases and other metabolic risk factors among them as there is a familial aggregation of NAFLD. One can predict the occurrence of NAFLD in the next generation using the NAFLD16 score.

Genetic predisposition similarities between NASH and ASH: Identification of new therapeutic targets.

Fatty liver disease can be triggered by a combination of excess alcohol, dysmetabolism and other environmental cues, which can lead to steatohepatitis and can evolve to acute/chronic liver failure and hepatocellular carcinoma, especially in the presence of shared inherited determinants. The recent identification of the genetic causes of steatohepatitis is revealing new avenues for more effective risk stratification. Discovery of the mechanisms underpinning the detrimental effect of causal mutations has led to some breakthroughs in the comprehension of the pathophysiology of steatohepatitis. Thanks to this approach, hepatocellular fat accumulation, altered lipid droplet remodelling and lipotoxicity have now taken centre stage, while the role of adiposity and gut-liver axis alterations have been independently validated. This process could ignite a virtuous research cycle that, starting from human genomics, through omics approaches, molecular genetics and disease models, may lead to the development of new therapeutics targeted to patients at higher risk. Herein, we also review how this knowledge has been applied to: a) the study of the main PNPLA3 I148M risk variant, up to the stage of the first in-human therapeutic trials; b) highlight a role of MBOAT7 downregulation and lysophosphatidyl-inositol in steatohepatitis; c) identify IL-32 as a candidate mediator linking lipotoxicity to inflammation and liver disease. Although this precision medicine drug discovery pipeline is mainly being applied to non-alcoholic steatohepatitis, there is hope that successful products could be repurposed to treat alcohol-related liver disease as well.

3D disorganization and rearrangement of genome provide insights into pathogenesis of NAFLD by integrated Hi-C, Nanopore, and RNA sequencing.

The three-dimensional (3D) conformation of chromatin is integral to the precise regulation of gene expression. The 3D genome and genomic variations in non-alcoholic fatty liver disease (NAFLD) are largely unknown, despite their key roles in cellular function and physiological processes. High-throughput chromosome conformation capture (Hi-C), Nanopore sequencing, and RNA-sequencing (RNA-seq) assays were performed on the liver of normal and NAFLD mice. A high-resolution 3D chromatin interaction map was generated to examine different 3D genome hierarchies including A/B compartments, topologically associated domains (TADs), and chromatin loops by Hi-C, and whole genome sequencing identifying structural variations (SVs) and copy number variations (CNVs) by Nanopore sequencing. We identified variations in thousands of regions across the genome with respect to 3D chromatin organization and genomic rearrangements, between normal and NAFLD mice, and revealed gene dysregulation frequently accompanied by these variations. Candidate target genes were identified in NAFLD, impacted by genetic rearrangements and spatial organization disruption. Our data provide a high-resolution 3D genome interaction resource for NAFLD investigations, revealed the relationship among genetic rearrangements, spatial organization disruption, and gene regulation, and identified candidate genes associated with these variations implicated in the pathogenesis of NAFLD. The newly findings offer insights into novel mechanisms of NAFLD pathogenesis and can provide a new conceptual framework for NAFLD therapy.

From sugar to liver fat and public health: systems biology driven studies in understanding non-alcoholic fatty liver disease pathogenesis.

Non-alcoholic fatty liver disease (NAFLD) is now a major public health concern with an estimated prevalence of 25-30% of adults in many countries. Strongly associated with obesity and the metabolic syndrome, the pathogenesis of NAFLD is dependent on complex interactions between genetic and environmental factors that are not completely understood. Weight loss through diet and lifestyle modification underpins clinical management; however, the roles of individual dietary nutrients (e.g. saturated and n-3 fatty acids; fructose, vitamin D, vitamin E) in the pathogenesis or treatment of NAFLD are only partially understood. Systems biology offers valuable interdisciplinary methods that are arguably ideal for application to the studying of chronic diseases such as NAFLD, and the roles of nutrition and diet in their molecular pathogenesis. Although present in silico models are incomplete, computational tools are rapidly evolving and human metabolism can now be simulated at the genome scale. This paper will review NAFLD and its pathogenesis, including the roles of genetics and nutrition in the development and progression of disease. In addition, the paper introduces the concept of systems biology and reviews recent work utilising genome-scale metabolic networks and developing multi-scale models of liver metabolism relevant to NAFLD. A future is envisioned where individual genetic, proteomic and metabolomic information can be integrated computationally with clinical data, yielding mechanistic insight into the pathogenesis of chronic diseases such as NAFLD, and informing personalised nutrition and stratified medicine approaches for improving prognosis.

A Novel Phosphoinositide-3-kinase Adapter Protein 1 Gene Missense Mutation in Familial Cirrhosis.

Familial cirrhosis is a condition that is associated with the presence of liver disease with genetic linkage among multiple family members in a generation or in multiple generations. With cirrhosis, most of these disease pathogeneses are related to a defect of an enzyme/transport protein leading to a deranged metabolic pathway with variable prevalence. Many studies and high-quality metanalyses have shed light on genetic linkage associated with nonalcoholic fatty liver disease and steatohepatitis such as the PNPLA3, MBOAT7, and TM6SF2 variants. In this report, we shed light on a novel missense mutation associated with cirrhosis in a family of brothers associated with phosphoinositide-3-kinase adapter protein 1 gene through high-output whole exosome gene sequencing methodology.