What Does the Future Hold for Patients With Nonalcoholic Steatohepatitis: Diagnostic Strategies and Treatment Options in 2021 and Beyond?

Efficacy of pharmacologic interventions on magnetic resonance imaging biomarkers in patients with nonalcoholic fatty liver disease: systematic review and network meta-analysis

BACKGROUND AND AIM

Several agents are under investigation for nonalcoholic fatty liver disease (NAFLD). We assessed the comparative efficacy of pharmacologic interventions for patients with NAFLD focusing on magnetic resonance imaging (MRI) biomarkers.

METHODS

We searched Medline, Embase, and CENTRAL. We included randomized controlled trials of more than 12 weeks of intervention that recruited patients with biopsy-confirmed or MRI-confirmed NAFLD and assessed the efficacy of interventions on liver fat content (LFC) and fibrosis by means of MRI. We performed random-effects frequentist network meta-analyses and assessed confidence in our estimates using the CINeMA (Confidence in Network Meta-Analysis) approach.

RESULTS

We included 47 trials (8583 patients). Versus placebo, thiazolidinediones were the most efficacious for the absolute change in LFC, followed by vitamin E, fibroblast growth factor (FGF) analogs, and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) with mean differences ranging from -7.46% (95% confidence interval [-11.0, -3.9]) to -4.36% (-7.2, -1.5). No differences between drug classes were evident. Patients receiving GLP-1 RAs or glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 RAs were more likely to achieve ≥30% relative reduction in LFC. Among agents, efruxifermin produced the largest reduction in LFC compared to placebo [-13.5% (-18.5, -8.5)], followed by pioglitazone, while being superior to most interventions. The effect of interventions on magnetic resonance elastography assessed fibrosis was small and insignificant. The confidence in our estimates was low to very low.

CONCLUSIONS

Several drug classes may reduce LFC in patients with NAFLD without a significant effect on fibrosis; nevertheless, trial duration was small, and confidence in the effect estimates was low.

Prevalence of Nonalcoholic Steatohepatitis and Associated Fibrosis Stages Among US Adults Using Imaging-Based vs Biomarker-Based Noninvasive Tests

Introduction: Nonalcoholic fatty liver disease (NAFLD) is believed to be the most common chronic liver disease worldwide. Therapies are under development for nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD, such that the prevalence of NASH with liver fibrosis, which is likely to require treatment, may be of interest to healthcare decision makers. Noninvasive tests are used in initial screening for NASH, as well as in observational studies of NASH prevalence. However, existing evidence does not address how estimated prevalence varies with different noninvasive tests. This analysis estimated the prevalence of NASH among US adults and assessed variation with different noninvasive tests. Methods: A cross-sectional analysis was conducted using the 2017-March 2020 National Health and Nutrition Examination Survey cycle. Participants with presumed NAFLD (steatosis and without alternative causes of liver disease) were identified, among whom NASH was predicted based on FAST score, Fibrosis-4 (FIB-4), and AST-to-Platelet Ratio Index (APRI) cutoffs across 11 scenarios. Among NASH participants, fibrosis stages were explored based on distribution across the spectrum of liver-stiffness measurements. Results: Among participants with complete data for the analysis (N=6969), prevalence of presumed NAFLD was 25.6%. Within presumed NAFLD, prediction of NASH using imaging-based NIT cutoffs yielded estimated prevalence of 1.3%-4.8% (3.3 million-12.2 million) based on FAST score cutoffs from 0.35-0.67. Using biomarker-based NIT cutoffs yielded estimated prevalence of 0.4%-12.3% (1.0 million-14.5 million) based on FIB-4 cutoffs from 0.90-2.67, and 0.1%-1.9% (0.2-5.0 million) based on APRI cutoffs from 0.50-1.50. Conclusion: Prevalence of NASH among US adults was estimated to range from 1.3% to 4.8% when predicted using imaging-based noninvasive test values for participants with presumed NAFLD, generally aligning with estimates in the literature of prevalence of biopsy-confirmed NASH. Use of biomarker-based noninvasive test values for prediction of NASH yielded a wider range of estimates with FIB-4, and a considerably lower range of estimates with APRI.

Spatial Omics Reveals that Cancer-Associated Glycan Changes Occur Early in Liver Disease Development in a Western Diet Mouse Model of MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a progressive disease and comprises different stages of liver damage; it is significantly associated with obese and overweight patients. Untreated MASLD can progress to life-threatening end-stage conditions, such as cirrhosis and liver cancer. N-Linked glycosylation is one of the most common post-translational modifications in the cell surface and secreted proteins. N-Linked glycan alterations have been established to be signatures of liver diseases. However, the N-linked glycan changes during the progression of MASLD to liver cancer are still unknown. Here, we induced different stages of MASLD in mice and liver-cancer-related phenotypes and elucidated the N-glycome profile during the progression of MASLD by quantitative and qualitative profiling in situ using matrix-assisted laser desorption ionization (MALDI) imaging mass spectrometry (IMS). Importantly, we identified specific N-glycan structures including fucosylated and highly branched N-linked glycans at very early stages of liver injury (steatosis), which in humans are associated with cancer development, establishing the importance of these modifications with disease progression. Finally, we report that N-linked glycan alterations can be observed in our models by MALDI-IMS before liver injury is identified by histological analysis. Overall, we propose these findings as promising biomarkers for the early diagnosis of liver injury in MASLD.

LEARN algorithm: a novel option for predicting non-alcoholic steatohepatitis

Background

There is an unmet need for accurate non-invasive methods to diagnose non-alcoholic steatohepatitis (NASH). Since impedance-based measurements of body composition are simple, repeatable and have a strong association with non-alcoholic fatty liver disease (NAFLD) severity, we aimed to develop a novel and fully automatic machine learning algorithm, consisting of a deep neural network based on impedance-based measurements of body composition to identify NASH [the bioeLectrical impEdance Analysis foR Nash (LEARN) algorithm].

Methods

A total of 1,259 consecutive subjects with suspected NAFLD were screened from six medical centers across China, of which 766 patients with biopsy-proven NAFLD were included in final analysis. These patients were randomly subdivided into the training and validation groups, in a ratio of 4:1. The LEARN algorithm was developed in the training group to identify NASH, and subsequently, tested in the validation group.

Results

The LEARN algorithm utilizing impedance-based measurements of body composition along with age, sex, pre-existing hypertension and diabetes, was able to predict the likelihood of having NASH. This algorithm showed good discriminatory ability for identifying NASH in both the training and validation groups [area under the receiver operating characteristics (AUROC): 0.81, 95% CI: 0.77-0.84 and AUROC: 0.80, 95% CI: 0.73-0.87, respectively]. This algorithm also performed better than serum cytokeratin-18 neoepitope M30 (CK-18 M30) level or other non-invasive NASH scores (including HAIR, ION, NICE) for identifying NASH (P value <0.001). Additionally, the LEARN algorithm performed well in identifying NASH in different patient subgroups, as well as in subjects with partial missing body composition data.

Conclusions

The LEARN algorithm, utilizing simple easily obtained measures, provides a fully automated, simple, non-invasive method for identifying NASH.

Challenges and opportunities in NASH drug development

Nonalcoholic fatty liver disease (NAFLD) and its more severe form, nonalcoholic steatohepatitis (NASH), represent a growing worldwide epidemic and a high unmet medical need, as no licensed drugs have been approved thus far. Currently, histopathological assessment of liver biopsies is mandatory as a primary endpoint for conditional drug approval. This requirement represents one of the main challenges in the field, as there is substantial variability in this invasive histopathological assessment, which leads to dramatically high screen-failure rates in clinical trials. Over the past decades, several non-invasive tests have been developed to correlate with liver histology and, eventually, outcomes to assess disease severity and longitudinal changes non-invasively. However, further data are needed to ensure their endorsement by regulatory authorities as alternatives to histological endpoints in phase 3 trials. This Review describes the challenges of drug development in NAFLD-NASH trials and potential mitigating strategies to move the field forward.

Nonalcoholic fatty liver disease from a primary care perspective

Nonalcoholic fatty liver disease (NAFLD) affects up to one-third of the US population. Approximately one-fifth of patients with NAFLD have nonalcoholic steatohepatitis (NASH), characterized by hepatocyte damage and inflammation with or without fibrosis. NASH leads to greater risk of liver-related complications and liver-related mortality, with the poorest outcomes seen in patients with advanced fibrosis. NASH is also associated with other metabolic comorbidities and conveys an increased risk of adverse cardiovascular outcomes and extrahepatic cancers. Despite its high prevalence, NAFLD is frequently underdiagnosed. This is a significant concern, given that early diagnosis of NAFLD is a key step in preventing progression to NASH. In this review, we describe the clinical impact of NASH from the perspective of both the clinician and the patient. In addition, we provide practical guidance on the diagnosis and management of NASH for primary care providers, who play a pivotal role in the frontline care of patients with NASH, and we use case studies to illustrate real-world scenarios encountered in the primary care setting.

Effect of pegbelfermin on NASH and fibrosis-related biomarkers and correlation with histological response in the FALCON 1 trial

Background & Aims

FALCON 1 was a phase IIb study of pegbelfermin in patients with non-alcoholic steatohepatitis (NASH) and stage 3 fibrosis. This FALCON 1 post hoc analysis aimed to further assess the effect of pegbelfermin on NASH-related biomarkers, correlations between histological assessments and non-invasive biomarkers, and concordance between the week 24 histologically assessed primary endpoint response and biomarkers.

Methods

Blood-based composite fibrosis scores, blood-based biomarkers, and imaging biomarkers were evaluated for patients with available data from FALCON 1 at baseline through week 24. SomaSignal tests assessed protein signatures of NASH steatosis, inflammation, ballooning, and fibrosis in blood. Linear mixed-effect models were fit for each biomarker. Correlations and concordance were assessed between blood-based biomarkers, imaging, and histological metrics.

Results

At week 24, pegbelfermin significantly improved blood-based composite fibrosis scores (ELF, FIB-4, APRI), fibrogenesis biomarkers (PRO-C3 and PC3X), adiponectin, CK-18, hepatic fat fraction measured by MRI-proton density fat fraction, and all four SomaSignal NASH component tests. Correlation analyses between histological and non-invasive measures identified four main categories: steatosis/metabolism, tissue injury, fibrosis, and biopsy-based metrics. Concordant and discordant effects of pegbelfermin on the primary endpoint vs. biomarker responses were observed; the most clear and concordant effects were on measures of liver steatosis and metabolism. A significant association between hepatic fat measured histologically and by imaging was observed in pegbelfermin arms.

Conclusions

Pegbelfermin improved NASH-related biomarkers most consistently through improvement of liver steatosis, though biomarkers of tissue injury/inflammation and fibrosis were also improved. Concordance analysis shows that non-invasive assessments of NASH support and exceed the improvements detected by liver biopsy, suggesting that greater consideration should be given to the totality of available data when evaluating the efficacy of NASH therapeutics.

Clinical trial number

Post hoc analysis of NCT03486899.

Impact and implications

FALCON 1 was a study of pegbelfermin vs. placebo in patients with non-alcoholic steatohepatitis (NASH) without cirrhosis; in this study, patients who responded to pegbelfermin treatment were identified through examination of liver fibrosis in tissue samples collected through biopsy. In the current analysis, non-invasive blood- and imaging-based measures of fibrosis, liver fat, and liver injury were used to determine pegbelfermin treatment response to see how they compared with the biopsy-based results. We found that many of the non-invasive tests, particularly those that measured liver fat, identified patients who responded to pegbelfermin treatment, consistent with the liver biopsy findings. These results suggest that there may be additional value in using data from non-invasive tests, along with liver biopsy, to evaluate how well patients with NASH respond to treatment.

Noninvasive biochemical markers and surrogate scores in evaluating nonalcoholic steatohepatitis

The histological features of nonalcoholic steatohepatitis (NASH) are the presence of hepatic steatosis with concomitant inflammation, ballooned hepatocytes, and potential fibrosis, which can lead to liver cirrhosis. To reduce the need for liver biopsy, that is still the gold standard for diagnosing NASH, various noninvasive biomarkers have been investigated. This narrative review summarizes the current knowledge about noninvasive diagnostic biomarkers and scores proposed for patients with NASH. A search was performed in the main medical literature databases. The following search terms were used: NASH, noninvasive biomarkers or NASH scores and panels. We focused only on studies assessing NASH diagnosis or predictive values for biomarkers, panels and scores. Data on their accuracy in predicting NASH were collected. Several panels such as NAFLD Fibrosis Score (NFS), Fibrosis-4 (FIB-4), and FibroMeter presented good predictive values of NASH, with novel proteomics panels such as the NAFLD Fibrosis Protein Panel (NFPP) using mainly the adisintegrin and metalloproteinase with thrombospondin motifs like 2 (ADAMTSL2) that showed an advantage in predicting NASH compared to NFS and FIB-4. Another novel panel, Index of NASH (ION) performed better than cytokeratin 18 (CK-18) in excluding severe fibrosis, but the overall accuracy of ION and CK-18 was modest compared to NFS and FIB-4 as it did not provide any significant advantage. Noninvasive biomarkers are currently unable to replace liver biopsy and histological assessment. However, they may play a key and vital role in triaging patients for liver biopsy, lowering the related financial burden. Future studies are needed to verify the predictive values of the newly emerging tests and panels as well as to find more affordable and reliable noninvasive early diagnostic tools.

Applications of Quantitative Systems Pharmacology (QSP) in Drug Development for NAFLD and NASH and Its Regulatory Application

Nonalcoholic steatohepatitis (NASH) is a widely prevalent disease, but approved pharmaceutical treatments are not available. As such, there is great activity within the pharmaceutical industry to accelerate drug development in this area and improve the quality of life and reduce mortality for NASH patients. The use of quantitative systems pharmacology (QSP) can help make this overall process more efficient. This mechanism-based mathematical modeling approach describes both the pathophysiology of a disease and how pharmacological interventions can modify pathophysiologic mechanisms. Multiple capabilities are provided by QSP modeling, including the use of model predictions to optimize clinical studies. The use of this approach has grown over the last 20 years, motivating discussions between modelers and regulators to agree upon methodologic standards. These include model transparency, documentation, and inclusion of clinical pharmacodynamic biomarkers. Several QSP models have been developed that describe NASH pathophysiology to varying extents. One specific application of NAFLDsym, a QSP model of NASH, is described in this manuscript. Simulations were performed to help understand if patient behaviors could help explain the relatively high rate of fibrosis stage reductions in placebo cohorts. Simulated food intake and body weight fluctuated periodically over time. The relatively slow turnover of liver collagen allowed persistent reductions in predicted fibrosis stage despite return to baseline for liver fat, plasma ALT, and the NAFLD activity score. Mechanistic insights such as this that have been derived from QSP models can help expedite the development of safe and effective treatments for NASH patients.

Growth hormone deficiency and NAFLD: An overlooked and underrecognized link

Growth hormone and its mediator insulin‐like growth factor‐1 exert their effect on different organs and control various physiologic metabolic processes. Adult growth hormone deficiency (AGHD) presents with one or more components of metabolic syndrome and can be associated with nonalcoholic fatty liver disease (NAFLD). AGHD is present in spectrum of hypothalamic/pituitary disorders as well as cranial radiation of brain tumors and often remains underdiagnosed or untreated due to its nonspecific symptoms, relatively difficult diagnosis in some clinical scenarios, and various barriers to treatment. NAFLD usually develops soon after diagnosis of AGHD and might progress rapidly to nonalcoholic steatohepatitis (NASH) with advanced fibrosis, eventually requiring liver transplantation. A timely initiation of growth hormone replacement therapy might be important, although studies so far have demonstrated controversial results on NAFLD, primarily due to small sample size and different diagnostic methods of NAFLD. Increased awareness of the association between AGHD and NAFLD would facilitate early diagnosis of NAFLD and NASH if present. Therefore, a multidisciplinary approach involving hepatology and endocrinology should become a standard of care for these patients.

NAFLD: Mechanisms, Treatments, and Biomarkers

Nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic-associated fatty liver disease (MAFLD), is one of the most common causes of liver diseases worldwide. NAFLD is growing in parallel with the obesity epidemic. No pharmacological treatment is available to treat NAFLD, specifically. The reason might be that NAFLD is a multi-factorial disease with an incomplete understanding of the mechanisms involved, an absence of accurate and inexpensive imaging tools, and lack of adequate non-invasive biomarkers. NAFLD consists of the accumulation of excess lipids in the liver, causing lipotoxicity that might progress to metabolic-associated steatohepatitis (NASH), liver fibrosis, and hepatocellular carcinoma. The mechanisms for the pathogenesis of NAFLD, current interventions in the management of the disease, and the role of sirtuins as potential targets for treatment are discussed here. In addition, the current diagnostic tools, and the role of non-coding RNAs as emerging diagnostic biomarkers are summarized. The availability of non-invasive biomarkers, and accurate and inexpensive non-invasive diagnosis tools are crucial in the detection of the early signs in the progression of NAFLD. This will expedite clinical trials and the validation of the emerging therapeutic treatments.

Discovery of farnesoid X receptor and its role in bile acid metabolism

In 1995, the nuclear hormone orphan receptor farnesoid X receptor (FXR, NR1H4) was identified as a farnesol receptor expressed mainly in liver, kidney, and adrenal gland of rats. In 1999, bile acids were identified as endogenous FXR ligands. Subsequently, FXR target genes involved in the regulation of hepatic bile acid synthesis, secretion, and intestinal re-absorption were identified. FXR signaling was proposed as a mechanism of feedback regulation of the rate-limiting enzyme for bile acid synthesis, cholesterol 7⍺-hydroxylase (CYP7A1). The primary bile acids synthesized in the liver are transformed to secondary bile acids by the gut microbiota. The gut-to-liver axis plays a critical role in the regulation of bile acid synthesis, composition and circulating bile acid pool size, which in turn regulates glucose, lipid, and energy metabolism. Dysregulation of bile acid metabolism and FXR signaling in the gut-to-liver axis contributes to metabolic diseases including obesity, diabetes, and non-alcoholic fatty liver disease. This review will cover the discovery of FXR as a bile acid sensor in the regulation of bile acid metabolism and as a metabolic regulator of lipid, glucose, and energy homeostasis. It will also provide an update of FXR functions in the gut-to-liver axis and the drug therapies targeting bile acids and FXR for the treatment of liver metabolic diseases.

Comprehensive Review and Updates on Holistic Approach Towards Non-Alcoholic Fatty Liver Disease Management with Cardiovascular Disease

PURPOSE OF REVIEW

The global prevalence of non-alcoholic fatty liver disease (NAFLD) presents an unmet need in treating these, often asymptomatic, individuals. In this review, we summarised NAFLD management and described recent developments in non-alcoholic steatohepatitis (NASH) therapeutics that can shape the future of NAFLD.

RECENT FINDINGS

A multi-disciplinary effort in promoting sustainable lifestyle measures is paramount, with the goal of either limiting energy surplus alone or in combination with targeting downstream pathways of inflammation and fibrosis. Several antidiabetic medications like PPAR-γ agonist and glucagon-like peptide receptor agonists have beneficial effects on the metabolic profile as well as NASH histology. Vitamin E has shown promise in specific groups of patients with the haptoglobin2 allele protein. Newer drugs have demonstrated promising results in NASH resolution and fibrosis improvement such as obeticholic acid, resmetirom, aramchol, efruxifermin, aldafermin and lanifibranor. Apart from discussing the results of late stage clinical trials and the possible challenges in managing these patients with limited approved therapies, we also discussed the specific management of comorbidities (diabetes, hypertension, hyperlipidaemia, cardiovascular diseases) in NAFLD patients. Treatment strategy needs to target improvements in liver-related outcomes and cardiometabolic profile.

Heightened levels of plasma growth differentiation factor 15 in men living with HIV

Plasma biomarkers that reflect energy balance disorders in people living with HIV (PLWH) remain limited. Growth differentiation factor 15 (GDF15) abundance in plasma of mice and humans induces negative energy balance but also becomes highly elevated in obesity and other metabolic diseases. We sought to compare plasma GDF15 levels in PLWH and HIV-negative persons and mouse models expressing the HIV accessory protein Vpr (that recapitulate HIV-associated metabolic disorders) and determine their relationship to metabolic parameters. We measured liver Gdf15 mRNA levels and plasma GDF15 levels in male Vpr mice and littermate controls. In parallel, we analyzed plasma GDF15 levels in 18 male PLWH on stable, long-term antiretroviral therapy and 13 HIV-negative men (6 healthy controls and 7 with metabolic syndrome). Plasma GDF15 levels were correlated with anthropometric and immune cell parameters in humans. Gene expression analysis of Vpr mouse liver demonstrated elevated Gdf15 mRNA. Plasma GDF15 levels were also higher in Vpr mouse models. Levels of plasma GDF15 in PLWH were greater than in both HIV-negative groups and correlated positively with the CD4/CD8 T cell ratio in PLWH. Plasma GDF15 levels correlated positively with age in the HIV-negative subjects but not in PLWH. Since GDF15 levels predict fatty liver disease and energy balance disorders, further studies are warranted to determine the effect of GDF15 in mediating the metabolic disturbances that occur in Vpr mice and PLWH.

Imaging Mass Spectrometry Reveals Alterations in N-Linked Glycosylation That Are Associated With Histopathological Changes in Nonalcoholic Steatohepatitis in Mouse and Human

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD) and is characterized by inflammation, hepatocyte injury, and fibrosis. Further, NASH is a risk factor for cirrhosis and hepatocellular carcinoma. Previous research demonstrated that serum N-glycan profiles can be altered in NASH patients. Here, we hypothesized that these N-glycan modifications may be associated with specific liver damage in NAFLD and NASH. To investigate the N-glycome profile in tissue, imaging mass spectrometry was used for a qualitative and quantitative in situ N-linked glycan analysis of mouse and human NAFLD/NASH tissue. A murine model was used to induce NAFLD and NASH through ad libitum feeding with either a high-fat diet or a Western diet, respectively. Mice fed a high-fat diet or Western diet developed inflammation, steatosis, and fibrosis, consistent with NAFLD/NASH phenotypes. Induction of NAFLD/NASH for 18 months using high caloric diets resulted in increased expression of mannose, complex/fucosylated, and hybrid N-glycan structures compared to control mouse livers. To validate the animal results, liver biopsy specimens from 51 human NAFLD/NASH patients representing the full range of NASH Clinical Research Network fibrosis stages were analyzed. Importantly, the same glycan alterations observed in mouse models were observed in human NASH biopsies and correlated with the degree of fibrosis. In addition, spatial glycan alterations were localized specifically to histopathological changes in tissue like fibrotic and fatty areas. We demonstrate that the use of standard staining's combined with imaging mass spectrometry provide a full profile of the origin of N-glycan modifications within the tissue. These results indicate that the spatial distribution of abundances of released N-glycans correlate with regions of tissue steatosis associated with NAFLD/NASH.