Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - EPoS (Elucidating Pathways of Steatohepatitis)

Teaser

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with the Metabolic Syndrome (MetS) including obesity, Type 2 Diabetes Mellitus (T2DM) and dyslipidaemia. NAFLD prevalence has increased dramatically in concert with the rapidly progressing epidemics of both adult...

Summary

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with the Metabolic Syndrome (MetS) including obesity, Type 2 Diabetes Mellitus (T2DM) and dyslipidaemia. NAFLD prevalence has increased dramatically in concert with the rapidly progressing epidemics of both adult and childhood obesity and T2DM. Furthermore, non-alcoholic steatohepatitis (NASH) is projected to be the principal aetiology for liver transplantation within the decade.

NAFLD is characterized by substantial inter-patient variability in terms of severity and rate of progression. However, what determines the progression to NASH and beyond is not clear and these groups can only be differentiated by liver biopsy, a costly and potentially risky invasive procedure. Key challenges are to understand the biological and environmental factors that drive inter-patient variability within the NAFLD spectrum and to use this understanding to develop robust methods for diagnosis, risk stratification (e.g. steatosis vs. NASH) and therapy so that effective medical care may be targeted to those at greatest risk.

The specific aims and objectives of the EPoS project are:
i. To generate high quality data defining the pathophysiology of NAFLD using a multi-‘omics’ approach
ii. To develop a multi-dimensional pathophysiological profile across the spectrum of NAFLD using a systems medicine platform
iii. To validate these findings and identify translatable mechanisms
iv. To validate findings against clinical outcomes
v. To measure health trends & clinical practice determinants

The ultimate goal will be to develop a global understanding of how host and environmental factors interact at the cellular, organ and organism level to promote the development of NAFLD and, importantly, the progression to fibrosing steatohepatitis (NASH) and end-stage liver disease; and so provide a clear path for integrating these datasets to inform cost effective diagnosis, prevention and treatment strategies in Europe.

Work performed

The ‘EPoS European NAFLD Registry’ database has been generated, initially with previously collected datasets. Prospective recruitment of patients into the NAFLD Registry and EPoS Biobank is continuing, as well as longitudinal follow-up of patients to determine natural history and disease outcomes.

Selection of a ‘core’ EPoS Cohort has been accomplished, and selection of the various subsets has either been done or is underway, including transfer of samples to the relevant partners, to allow the different ’omics studies to progress.

The GWAS data from the FLIP project has been extended by exome genotyping of stored DNA samples. A within-case analysis of the amalgamated data has confirmed a strong effect for PNPLA3 rs738409 as the most significant risk factor for steatosis and NAS score.

Metabolomic measurements in plasma samples of NALFD patients has generated a new “GSG index”, calculated as the ratio glutamic acid/(serine+glycine), for the non-invasive prediction of the severity of liver damage that can be validated in the EPoS cohort. GSG was found to increase with the degree of liver fibrosis and insulin resistance and to decrease after treatment with pioglitazone vs placebo. We have also found that the ratio of saturated to unsaturated plasma free fatty acid is related to insulin resistance and severity of NAFLD.
Furthermore, we showed that non-diabetic subjects with NAFLD have increased concentrations of angiopoietin-like-protein 4 (ANGPTL4) that mainly reflect alterations of lipid metabolism and increased IR, and that plasma levels of ANGPTL4 are increased proportionally to hepatic and systemic inflammation, degree of hepatic steatosis and fibrosis.An initial analysis examining the relationships between low gene count and clinical parameters, as well as for changes over time in metagenomic profile and microbiome richness, found that modifications in gene richness are observed 1 year after bariatric surgery.

Using mouse models, we have performed a variety of nutritional interventions to study MBOAT7 and PEPD candidate genes. As a result, HFD 45% Kcal and ALIOS diets have been validated as suitable nutritional challenges to evaluate the initial stages of fatty liver from NAFLD to mild NASH and proof of PEPD and MBOAT7 as determinants in liver homeostasis has been demonstrated. Investigation of hypoxia and hypoxia-inducible factors (HIFs) using other murine dietary models has shown that the hepatocyte expression of HIF2α is critical for NAFLD progression.

Robust assays for the novel collagen biomarkers have been produced and are ready for higher throughput measurements on patient samples.

Dissemination activities have been excellent, with 13 important journal papers published so far and 60 conference presentations or keynote lectures given. In addition, The EPoS consortium held the first one-day workshop entitled “Frontiers in Hepatology: Non-Alcoholic Fatty Liver Disease & The Metabolic Syndrome”. A preliminary exploitation plan has been written and will be issued very shortly.

Finally, the overall coordination and management of the project consortium has been successfully achieved by implementing detailed procedures covering planning, internal reporting and risk management. In addition, a replacement partner has been successfully integrated into the consortium.

Final results

One key achievement of EPoS is the ‘European NAFLD Registry’, the largest European cohort of patients with histologically diagnosed NAFLD, which will continue as a central collaborative resource after the end of EPoS.

Both animal models and studies in NAFLD patients are being directed to explore the pathophysiological mechanisms underlying the metabolic derangements associated with insulin resistance and the progression from liver damage to NASH. The direct patentability of results obtained as part of EPoS is limited, but in vivo functional studies in NAFLD patients are providing important data on the detrimental effect of foods enriched with sugar.

Work has identified potential biomarkers which are linked with gut microbial diversity, lipotoxicity, or free fatty acids. Although in the early stages, validation of these markers could provide potentially new therapeutic pathways to target to improve liver-related disease outcomes. Both collagen and non-collagen serum biomarkers, and associated assays, under development are also showing promise.

Mouse models are also unveiling novel targets for the discovery of biomarkers and the development of effective drugs for NASH. Work from the pre-clinical studies will be used to discern the molecular mechanism of NAFLD and fibrosis. This will provide insight into our understanding of the disease process and could reveal new drug targets for NAFLD.

Use of 2D and 3D cultures to model fatty liver disease will be used to identify mechanistic pathways underpinning disease development. These systems will be used to help validate findings from the ’omics work packages and bridge the translational gap between pre-clinical disease models and man.

We envisage that the discovery science carried out will attract the attention of healthcare providers to address primary prevention in the general population, and will attract the attention of industry for consultancy, for testing the prognostic/diagnostic significance of the factors/mediators identified in experimental protocols of NAFLD/NASH, validation/testing of drugs/inhibitors/selective antibodies and their role as potential therapeutic targets.

Website & more info

More info: http://www.epos-nafld.eu.