Resmetirom Ameliorates NASH-Model Mice by Suppressing STAT3 and NF-κB Signaling Pathways in an RGS5-Dependent Manner

Beneficial effects of MGL-3196 and BAM15 combination in a mouse model of fatty liver disease

BACKGROUND AND AIM

Metabolic dysfunction-associated steatohepatitis (MASH) is a metabolic disorder with limited treatment options. The thyroid hormone receptor (THR)-β agonist resmetirom/MGL-3196 (MGL) increases liver fat oxidation and has been approved for treating adult MASH. However, over 60% of patients receiving MGL treatment do not achieve MASH resolution. Therefore, we investigated the potential for combination therapy of MGL with the mitochondrial uncoupler BAM15 to improve fatty liver disease outcomes in the GAN mouse model of MASH.

METHODS

C57BL/6J male mice were fed GAN diet for 38 weeks before stratification and randomization to treatments including MGL, BAM15, MGL + BAM15, or no drug control for 8 weeks. Treatments were admixed in diet and mice were pair-fed to control for drug intake. Treatment effectiveness was assessed by body weight, body composition, energy expenditure, glucose tolerance, tissue lipid content, and histological analyses.

RESULTS

MGL + BAM15 treatment resulted in better efficacy versus GAN control mice than either monotherapy in the context of energy expenditure, liver fat loss, glucose control, and fatty liver disease activity score. Improvements in ALT, liver mass, and plasma cholesterol were primarily driven by MGL, while improvements in body fat were primarily driven by BAM15. No treatments altered liver fibrosis.

CONCLUSIONS

MGL + BAM15 treatment had overall better efficacy to improve metabolic outcomes in mice fed GAN diet than either monotherapy alone. These data warrant further investigation into combination therapies of THR-β agonists and mitochondrial uncouplers for the potential treatment of disorders related to fatty liver, obesity, and insulin resistance.

Integrating behavioral interventions into a holistic approach to metabolic dysfunction-associated steatotic liver disease

INTRODUCTION

The therapeutic landscape of Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD) is rapidly evolving with the FDA approval of resmetirom, the first authorized molecule to treat metabolic dysfunction-associated steatohepatitis. Clinical trials are investigating other promising molecules. However, this focus on pharmacotherapy may overshadow lifestyle interventions, which remain the cornerstone of MASLD management. A significant percentage of patients with MASLD struggle with an underlying eating disorder, often a precursor to obesity. The obesity pandemic, exacerbated by the increasing prevalence of binge eating, underscores the need for a psychological approach to address their common roots.

AREAS COVERED

We reviewed the current evidence on behavioral interventions for MASLD. Interventions such as self-monitoring, goal setting, and frequent counseling, have proven effective in achieving at least 5% weight loss. Cognitive behavioral therapy is the first-line treatment for eating disorders and has shown efficacy in treating binge eating and obesity. Further research is needed to establish the optimal behavioral therapy for MASLD, focusing on enhancing compliance and achieving sustained weight loss through diet and physical exercise.

EXPERT OPINION

The treatment of MASLD should not rely solely on pharmacotherapy targeting a single-organ manifestation. Instead, we must consider behavioral interventions, emphasizing the pivotal role of a holistic approach to this multifaceted disorder. [Figure: see text].

New advances in drug development for metabolic dysfunction-associated diseases and alcohol-associated liver disease

Metabolic disorders are currently threatening public health worldwide. Discovering new targets and developing promising drugs will reduce the global metabolic-related disease burden. Metabolic disorders primarily consist of lipid and glucose metabolic disorders. Specifically, metabolic dysfunction-associated steatosis liver disease (MASLD) and alcohol-associated liver disease (ALD) are two representative lipid metabolism disorders, while diabetes mellitus is a typical glucose metabolism disorder. In this review, we aimed to summarize the new drug candidates with promising efficacy identified in clinical trials for these diseases. These drug candidates may provide alternatives for patients with metabolic disorders and advance the progress of drug discovery for the large disease burden.

Exploring Varied Treatment Strategies for Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a liver disorder characterized by steatosis with underlying metabolic risk factors. The prevalence of MASLD continues to rise, leading to increased patient risk of various complications. Recent research has been focused on new therapeutic strategies to reduce the incidence of MASLD and provide effective treatment plans to prevent further irreversible liver damage. The treatment approach is multifactorial, with a primary focus on weight loss and management of underlying comorbidities through lifestyle modifications, pharmacotherapy, or surgical options. Ongoing research is exploring new pharmacological therapies that could enhance the treatment of MASLD.

Role of Resmetirom, a Liver-Directed, Thyroid Hormone Receptor Beta-Selective Agonist, in Managing Nonalcoholic Steatohepatitis: A Systematic Review and Meta-Analysis

BACKGROUND

Resmetirom, a liver-directed, thyroid hormone receptor beta-selective agonist, has recently been approved to treat nonalcoholic steatohepatitis (NASH). This meta-analysis aimed to summarize the efficiency and safety of resmetirom in treating NASH.

METHODS

Electronic databases were searched for randomized controlled trials (RCTs) of resmetirom vs placebo in patients with NASH. The primary outcomes were the changes from baseline in hepatic fat content, liver histology, including NASH resolution, and noninvasive markers of hepatic fibrosis.

RESULTS

Three randomized controlled trials (n = 2231) met the inclusion criteria. Compared to placebo, resmetirom achieved greater reductions from baseline in hepatic fat content assessed by magnetic resonance imaging proton density fat fraction (for resmetirom 80 mg: MD -27.76% [95%CI: -32.84, -22.69]; for resmetirom 100 mg: MD -36.01% [95%CI: -41.54, -30.48]; P < .00001 for both) and FibroScan controlled attenuation parameter (for resmetirom 80 mg: MD -21.45 dBm [95%CI: -29.37, -13.52]; for resmetirom 100 mg: MD -25.51 dBm [95%CI: -33.53, -17.49]; P < .00001 for both). Resmetirom 80 mg outperformed placebo in NASH resolution and ≥2-point nonalcoholic fatty liver disease activity score reduction. Moreover, resmetirom 80 mg and 100 mg were superior to placebo in cytokeratin-18 (M30) reduction. Greater reductions in liver enzymes, lipids, and reverse triiodothyronine were observed in the resmetirom arms with no impact on triiodothyronine. Nausea and diarrhea were more common with resmetirom than with placebo; other adverse events were comparable.

CONCLUSION

Resmetirom improves hepatic fat content, liver enzymes, and fibrosis biomarkers in NASH patients. Resmetirom generally does not affect thyroid function and is well-tolerated.

Safety and efficacy of resmetirom in the treatment of patients with non-alcoholic steatohepatitis and liver fibrosis: a systematic review and meta-analysis

Introduction

Non-alcoholic fatty liver disease (NAFLD), spanning from non-alcoholic steatohepatitis (NASH) to liver fibrosis, poses a global health challenge amid rising obesity and metabolic syndrome rates. Effective pharmacological treatments for NASH and liver fibrosis are limited.

Objective

This study systematically reviews and meta-analyzes the safety and efficacy of resmetirom, a selective thyroid hormone receptor-β agonist, in NASH and liver fibrosis treatment. By analyzing data from clinical trials, we aim to offer evidence-based recommendations for resmetirom's use in managing these conditions and identify avenues for future research.

Methods

Electronic databases (PubMed, Scopus, Science Direct, Google Scholar, ClinicalTrials.gov, and Cochrane CENTRAL) were systematically searched, supplemented by manual screening of relevant sources. Only English-language randomized controlled trials were included. Data extraction, risk of bias assessment, pooled analyses, and meta-regression were performed.

Results

Three randomized controlled trials involving 2231 participants were analyzed. Resmetirom demonstrated significant reductions in hepatic fat fraction [standardized mean difference (SMD) -4.61, 95% CI -6.77 to -2.44, P < 0.0001], NASH resolution without worsening fibrosis [risk ratio (RR) 2.51, 95% CI 1.74-3.64, P = 0.00001), and liver fibrosis improvement (RR 2.31, 95% CI 1.20-4.44, P = 0.01). Secondary outcomes showed significant improvements in lipid profiles, liver enzymes, and NASH biomarkers with resmetirom treatment. Meta-regression revealed associations between covariates and primary outcomes.

Conclusion

Resmetirom exhibits promising efficacy in reducing hepatic fat, improving NASH resolution, and ameliorating liver fibrosis with a favorable safety profile. Further research is warranted to validate findings and optimize therapeutic strategies for NASH and liver fibrosis management.

Intrahepatic hypothyroidism in MASLD: Role of liver-specific thyromimetics including resmetirom

BACKGROUND AND AIMS

Thyroid hormones are important regulators of hepatic lipid homeostasis and whole-body energy expenditure. Recent evidence suggests that euthyroid individuals with metabolic dysfunction-associated steatohepatitis (MASH) develop intrahepatic hypothyroidism that promotes progression of MASH.

METHODS

A literature search was performed with Medline (PubMed), Scopus and Google Scholar electronic databases from inception till March 2024, using the following keywords: hypothyroidism and nonalcoholic fatty liver disease; MASLD and thyroid function; intrahepatic hypothyroidism; TRβ agonists; and resmetirom. Relevant studies were extracted that described pathogenesis of MASH in the context of thyroid functions.

RESULTS

In euthyroid individuals with MASH, there is decreased conversion of prohormone thyroxine (T4) to bioactive tri-iodothyronine (T3) and increased conversion of T4 to inactive metabolite reverse T3 (rT3). Consequently, reduced levels of T3 results in impaired intrahepatic TRβ signaling, a state of intrahepatic hypothyroidism, which promotes progression of MASH. Hepatic TRβ activation leads to metabolically beneficial effects in the liver including mitochondrial fatty acid uptake and β-oxidation, mitochondrial biogenesis, increasing surface low-density lipoprotein (LDL) receptor density and lowering of circulatory LDL-cholesterol. In recent years, selective thyroid hormone mimetics that exhibit TRβ-selective binding and liver-selective uptake have been designed. Resmetirom, a liver-specific thyromimetic, improves intrahepatic TRβ signaling and in clinical trials significantly improved liver inflammation, fibrosis and lipid profile in patients with MASH.

CONCLUSIONS

In euthyroid individuals with MASH, development of intrahepatic hypothyroidism results in further progression of the disease. In clinical trials, resmetirom treatment results in a significant improvement in steatosis, inflammation and fibrosis and is the first drug approved by the US Food and Drug Administration (FDA) for the treatment of noncirrhotic MASH with moderate to advanced fibrosis.

Synthesis and biological evaluation of the novel chrysin prodrug for non-alcoholic fatty liver disease treatment

Background: Chrysin (5,7-dihydroxyflavone) is a natural flavonoid that has been reported as a potential treatment for non-alcoholic fatty liver disease (NAFLD). However, extensive phase II metabolism and poor aqueous solubility led to a decrease in the chrysin concentration in the blood after oral administration, limiting its pharmacological development in vivo. Methods: In the present study, we synthesized a novel chrysin derivative prodrug (C-1) to address this issue. We introduced a hydrophilic prodrug group at the 7-position hydroxyl group, which is prone to phase II metabolism, to improve water solubility and mask the metabolic site. Further, we evaluated the ameliorative effects of C-1 on NAFLD in vitro and in vivo by NAFLD model cells and db/db mice. Results: In vitro studies indicated that C-1 has the ability to ameliorate lipid accumulation, cellular damage, and oxidative stress in NAFLD model cells. In vivo experiments showed that oral administration of C-1 at a high dose (69.3 mg/kg) effectively ameliorated hyperlipidemia and liver injury and reduced body weight and liver weight in db/db mice, in addition to alleviating insulin resistance. Proteomic analysis showed that C-1 altered the protein expression profile in the liver and particularly improved the expression of proteins associated with catabolism and metabolism. Furthermore, in our preliminary pharmacokinetic study, C-1 showed favorable pharmacokinetic properties and significantly improved the oral bioavailability of chrysin. Conclusion: Our data demonstrated that C-1 may be a promising agent for NAFLD therapy.

Current Therapeutical Approaches Targeting Lipid Metabolism in NAFLD

Nonalcoholic fatty liver disease (NAFLD, including nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH)) is a high-prevalence disorder, affecting about 1 billion people, which can evolve to more severe conditions like cirrhosis or hepatocellular carcinoma. NAFLD is often concomitant with conditions of the metabolic syndrome, such as central obesity and insulin-resistance, but a specific drug able to revert NAFL and prevent its evolution towards NASH is still lacking. With the liver being a key organ in metabolic processes, the potential therapeutic strategies are many, and range from directly targeting the lipid metabolism to the prevention of tissue inflammation. However, side effects have been reported for the drugs tested up to now. In this review, different approaches to the treatment of NAFLD are presented, including newer therapies and ongoing clinical trials. Particular focus is placed on the reverse cholesterol transport system and on the agonists for nuclear factors like PPAR and FXR, but also drugs initially developed for other conditions such as incretins and thyromimetics along with validated natural compounds that have anti-inflammatory potential. This work provides an overview of the different therapeutic strategies currently being tested for NAFLD, other than, or along with, the recommendation of weight loss.