End-points for drug treatment in NASH

Multispecies transcriptomics identifies SIKE as a MAPK repressor that prevents NASH progression

Nonalcoholic fatty liver (NAFL) remains relatively benign, but high-risk to end-stage liver diseases become highly prevalent when it progresses into nonalcoholic steatohepatitis (NASH). Our current understanding of the development of NAFL to NASH remains insufficient. In this study, we revealed MAP kinase (MAPK) activation as the most notable molecular signature associated with NASH progression across multiple species. Furthermore, we identified suppressor of IKKε (SIKE) as a conserved and potent negative controller of MAPK activation. Hepatocyte-specific overexpression of Sike prevented NASH progression in diet- and toxin-induced mouse NASH models. Mechanistically, SIKE directly interacted with TGF-β-activated kinase 1 (TAK1) and TAK1-binding protein 2 (TAB2) to interrupt their binding and subsequent TAK1-MAPK signaling activation. We found that indobufen markedly up-regulated SIKE expression and effectively improved NASH features in mice and macaques. These findings identify SIKE as a MAPK suppressor that prevents NASH progression and provide proof-of-concept evidence for targeting the SIKE-TAK1 axis as a potential NASH therapy.

A New Non-Obese Steatohepatitis Mouse Model with Cardiac Dysfunction Induced by Addition of Ethanol to a High-Fat/High-Cholesterol Diet

Non-obese metabolic dysfunction-associated steatotic liver disease (MASLD) has been associated with cardiovascular-related mortality, leading to a higher mortality rate compared to the general population. However, few reports have examined cardiovascular events in non-obese MASLD mouse models. In this study we created a mouse model to mimic this condition. In this study involving seven-week-old C57BL/6J male mice, two dietary conditions were tested: a standard high-fat/high-cholesterol diet (STHD-01) and a combined diet of STHD-01 and ethanol. Over periods of 6 and 12 weeks, we analyzed the effects on liver and cardiac tissues using various staining techniques and PCR. Echocardiography and blood tests were also performed to assess cardiac function and liver damage. The results showed that mice on the ethanol-supplemented STHD-01 diet developed signs of steatohepatitis and cardiac dysfunction, along with increased sympathetic activity, as early as 6 weeks. At 12 weeks, more pronounced exacerbations accompanied with cardiac dilation, advanced liver fibrosis, and activated myocardial fibrosis with sympathetic activation were observed. This mouse model effectively replicated non-obese MASLD and cardiac dysfunction over a 12-week period using a combined diet of STHD-01 and ethanol. This dietary approach highlighted that both liver inflammation and fibrosis, as well as cardiac dysfunction, could be significantly worsened due to the activation of the sympathetic nervous system. Our results indicate that alcohol, even when completely metabolized on the day of drinking, exacerbates the progression of non-obese MASLD and cardiac dysfunction.

Endpoints in NASH Clinical Trials: Are We Blind in One Eye?

This narrative review aims to illustrate the notion that nonalcoholic steatohepatitis (NASH), recently renamed metabolic dysfunction-associated steatohepatitis (MASH), is a systemic metabolic disorder featuring both adverse hepatic and extrahepatic outcomes. In recent years, several NASH trials have failed to identify effective pharmacological treatments and, therefore, lifestyle changes are the cornerstone of therapy for NASH. with this context, we analyze the epidemiological burden of NASH and the possible pathogenetic factors involved. These include genetic factors, insulin resistance, lipotoxicity, immuno-thrombosis, oxidative stress, reprogramming of hepatic metabolism, and hypoxia, all of which eventually culminate in low-grade chronic inflammation and increased risk of fibrosis progression. The possible explanations underlying the failure of NASH trials are also accurately examined. We conclude that the high heterogeneity of NASH, resulting from variable genetic backgrounds, exposure, and responses to different metabolic stresses, susceptibility to hepatocyte lipotoxicity, and differences in repair-response, calls for personalized medicine approaches involving research on noninvasive biomarkers. Future NASH trials should aim at achieving a complete assessment of systemic determinants, modifiers, and correlates of NASH, thus adopting a more holistic and unbiased approach, notably including cardiovascular-kidney-metabolic outcomes, without restricting therapeutic perspectives to histological surrogates of liver-related outcomes alone.

Non-alcoholic fatty liver disease: the pathologist's perspective

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of diseases characterized by fatty accumulation in hepatocytes, ranging from steatosis, non-alcoholic steatohepatitis, to cirrhosis. While histopathological evaluation of liver biopsies plays a central role in the diagnosis of NAFLD, limitations such as the problem of interobserver variability still exist and active research is underway to improve the diagnostic utility of liver biopsies. In this article, we provide a comprehensive overview of the histopathological features of NAFLD, the current grading and staging systems, and discuss the present and future roles of liver biopsies in the diagnosis and prognostication of NAFLD.

Effect of pharmacological interventions and placebo on liver Histology in nonalcoholic steatohepatitis: A network meta-analysis

BACKGROUND

The aims of this study were to quantify the histological improvement and its risk factors in patients with NASH enrolled in the placebo arms of randomized controlled trials (RCTs), and to indirectly compare the effect of several investigational drugs for NASH on validated histological outcomes.

DATA SYNTHESIS

A comprehensive search was conducted to detect phase 2 and 3 RCTs comparing pharmacological interventions in patients with NASH. According to Food and Drug Administration (FDA) recommendations, primary outcomes included: 1) NASH resolution without worsening of fibrosis; 2) At least 1-point reduction in fibrosis without worsening of NASH. Meta-analysis and meta-regressions were conducted on placebo arms, while network meta-analysis was performed on intervention arms. A total of 15 RCTs met the eligibility criteria. The meta-analysis on placebo arms showed a pooled estimate rate of 17% (95%C.I. 12%-23%;I² = 86%; p < 0.01) for NASH resolution without worsening of fibrosis and of 21% (95%C.I. 13%-31%;I² = 84%; p < 0.01) for ≥1stage improvement of fibrosis without worsening of NASH. Phase 3 (vs Phase 2)RCTs, older age and higher AST levels were significantly associated with progression of liver disease by univariate meta-regression. At network meta-analysis, Semaglutide (P-score 0.906), Pioglitazione alone (score 0.890) and plus Vitamin E (0.826) had the highest probability of being ranked the most effective intervention for NASH resolution without worsening of fibrosis, while Aldafermin (0.776), Lanifibranor (0.773) and Obeticholic acid (0.771) had the highest probability to achieve ≥1 stage of fibrosis improvement without worsening of NASH.

CONCLUSION

This study confirms the heterogeneity of histological progression of untreated patients with NASH and provides evidence to stratify patients according to identified risk factors in future RCTs of combination therapies. PROSPERO CRD42021287205.

Chronic ethanol consumption plus an atherogenic diet cause metabolic steatohepatitis with advanced liver fibrosis in apolipoprotein E/low-density lipoprotein receptor double-knockout mice

BACKGROUND

Nonalcoholic steatohepatitis is the inflammatory subtype of nonalcoholic fatty liver disease with a high risk of progression to liver fibrosis. We investigated metabolic steatohepatitis with advanced liver fibrosis in apolipoprotein E/low-density lipoprotein receptor double-knockout (AL) mice fed a co-diet of ethanol with a low-carbohydrate-high-protein-high-fat atherogenic diet (AD) for 16 weeks. We also examined the underlying mechanisms, especially hepatic sympathetic activation, involved in the effects.

METHODS

We maintained 12-week-old male AL mice on AD and a standard chow diet (SCD) with or without ethanol treatment for 16 weeks. Age-matched male C57BL/6J mice on SCD without ethanol treatment served as controls. We conducted blood biochemical, histopathological, and fluorescence immunohistochemical, and reverse transcriptase polymerase chain reaction studies.

RESULTS

AL mice showed significant hyperlipidemia. AD induced increased body weight, hepatic steatosis, and hepatic damage; ethanol and the AD co-diet resulted in hepatic sympathetic activation accompanied by hepatic steatosis, lobular inflammation, bridging fibrosis, and hepatic damage. Hepatic Kupffer cells (KCs) and hepatic stellate cells (HSCs), which showed sympathetic activation, produced 4.4- to 9.4-fold more inflammatory factors (KC and KC-derived tumor necrosis factor-α, and chemokine [C-C motif] ligand 2) and 2.0- to 32.0-fold more fibrosis factors (HSC and HSC-derived transforming growth factor β1 and collagen 1a1); all p < 0.05 vs. controls.

CONCLUSIONS

We created a model of metabolic steatohepatitis with advanced liver fibrosis from coexisting hyperlipidemia and hepatic sympathetic activation in AL mice on a co-diet of ethanol and AD. KCs and HSCs became the cellular targets of hepatic sympathetic activation, which could play a role in the initiation and progression of metabolic steatohepatitis with advanced liver fibrosis.

Updates on novel pharmacotherapeutics for the treatment of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD), characterized with hepatocellular steatosis, ballooning, lobular inflammation, fibrotic progression, and insulin resistance. NASH may progress to cirrhosis and hepatocellular carcinoma (HCC), which are the major indications for liver transplantation and the causes for mortality. Thus far, there are no approved pharmacotherapeutics for the treatment of NASH. Given the complexity of NASH pathogenesis at multifaceted aspects, such as lipotoxicity, inflammation, insulin resistance, mitochondrial dysfunction and fibrotic progression, pharmacotherapeutics under investigation target different key pathogenic pathways to gain either the resolution of steatohepatitis or regression of fibrosis, ideally both. Varieties of pharmacologic candidates have been tested in clinical trials and have generated some positive results. On the other hand, recent failure or termination of a few phase II and III trials is disappointing in this field. In face to growing challenges in pharmaceutical development, this review intends to summarize the latest data of new medications which have completed phase II or III trials, and discuss the rationale and preliminary results of several combinatory options. It is anticipated that with improved understanding of NASH pathogenesis and critical endpoints, efficient pharmacotherapeutics will be available for the treatment of NASH with an acceptable safety profile.

Pathophysiological-based treatments of complications of cirrhosis

Detailed knowledge and understanding of the pathophysiological mechanisms and changes in hepatic and splanchnic function leading to the development of haemodynamic changes and portal hypertension in patients with cirrhosis are essential since it guides the search for targets to ameliorate liver-related abnormalities. Recent research has focused on the gut-liver axis, changes in intestinal permeability, translocation of bacterial products, and inflammation as important drivers of haemodynamic alterations and thereby targets for treatment. Additionally, treatment strategies should focus on microbiotic modulation, antiangiogenics, anti-inflammatory strategies, and modulation of bile acid metabolism. This paper aims to review contemporary pathophysiological-based treatment principles of the major complications of cirrhosis and portal hypertension and future targets for treatment.