Role of vitamin E in the treatment of non-alcoholic steatohepatitis

Emerging role of ferroptosis in metabolic dysfunction-associated steatotic liver disease: revisiting hepatic lipid peroxidation

Metabolic dysfunction-associated steatohepatitis (MASH) is characterised by cell death of parenchymal liver cells which interact with their microenvironment to drive disease activity and liver fibrosis. The identification of the major death type could pave the way towards pharmacotherapy for MASH. To date, increasing evidence suggest a type of regulated cell death, named ferroptosis, which occurs through iron-catalysed peroxidation of polyunsaturated fatty acids (PUFA) in membrane phospholipids. Lipid peroxidation enjoys renewed interest in the light of ferroptosis, as druggable target in MASH. This review recapitulates the molecular mechanisms of ferroptosis in liver physiology, evidence for ferroptosis in human MASH and critically appraises the results of ferroptosis targeting in preclinical MASH models. Rewiring of redox, iron and PUFA metabolism in MASH creates a proferroptotic environment involved in MASH-related hepatocellular carcinoma (HCC) development. Ferroptosis induction might be a promising novel approach to eradicate HCC, while its inhibition might ameliorate MASH disease progression.

Vitamin E intake is inversely associated with NAFLD measured by liver ultrasound transient elastography

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases, whose severe form is associated with oxidative stress. Vitamin E as an antioxidant has a protective potential in NAFLD. Whether dietary intake of vitamin E, supplementary vitamin E use, and total vitamin E have a preventive effect on NAFLD requires investigation. A cross-sectional study used data from the National Health and Nutrition Examination Survey (2017-2020) was conducted. Vitamin E intake, including dietary vitamin E, supplementary vitamin E use, and total vitamin E, was obtained from the average of two 24-h dietary recall interviews. The extent of hepatic steatosis was measured by liver ultrasound transient elastography and presented as controlled attenuated parameter (CAP) scores. Participants were diagnosed with NAFLD based on CAP threshold values of 288 dB/m and 263 dB/m. The statistical software R and survey-weighted statistical models were used to examine the association between vitamin E intake and hepatic steatosis and NAFLD. Overall, 6122 participants were included for NAFLD analysis. After adjusting for age, gender, race, poverty level index, alcohol consumption, smoking status, vigorous recreational activity, body mass index, abdominal circumference, hyperlipidemia, hypertension, diabetes, and supplementary vitamin E use, dietary vitamin E was inversely associated with NAFLD. The corresponding odds ratios (OR) and 95% confidence intervals (CI) of NAFLD for dietary vitamin E intake as continuous and the highest quartile were 0.9592 (0.9340-0.9851, P = 0.0039) and 0.5983 (0.4136-0.8654, P = 0.0091) (Ptrend = 0.0056). Supplementary vitamin E was significantly inversely associated with NAFLD (fully adjusted model: OR = 0.6565 95% CI 0.4569-0.9432, P = 0.0249). A marginal improvement in total vitamin E for NAFLD was identified. The ORs (95% CIs, P) for the total vitamin E intake as continuous and the highest quartile in the fully adjusted model were 0.9669 (0.9471-0.9871, P = 0.0029) and 0.6743 (0.4515-1.0071, P = 0.0538). Sensitivity analysis indicated these findings were robust. The protective effects of vitamin E significantly differed in the stratum of hyperlipidemia (Pinteraction < 0.05). However, no statistically significant results were identified when the threshold value was set as 263 dB/m. Vitamin E intake, encompassing both dietary and supplemental forms, as well as total vitamin E intake, demonstrated a protective association with NAFLD. Augmenting dietary intake of vitamin E proves advantageous in the prevention of NAFLD, particularly among individuals devoid of hyperlipidemia.

Metabolic-associated fatty liver disease: a selective review of pathogenesis, diagnostic approaches, and therapeutic strategies

Background

Metabolic associated fatty liver disease (MAFLD) is a novel terminology introduced in 2020 to provide a more accurate description of fatty liver disease associated with metabolic dysfunction. It replaces the outdated term nonalcoholic fatty liver disease (NAFLD) and aims to improve diagnostic criteria and tailored treatment strategies for the disease. NAFLD, the most prevalent liver disease in western industrialized nations, has been steadily increasing in prevalence and is associated with serious complications such as cirrhosis and hepatocellular carcinoma. It is also linked to insulin resistance syndrome and cardiovascular diseases. However, current studies on NAFLD have limitations in meeting necessary histological endpoints.

Objective

This literature review aims to consolidate recent knowledge and discoveries concerning MAFLD, integrating the diverse aspects of the disease. Specifically, it focuses on analyzing the diagnostic criteria for MAFLD, differentiating it from NAFLD and alcoholic fatty liver disease (AFLD), and exploring the epidemiology, clinical manifestations, pathogenesis, and management approaches associated with MAFLD. The review also explores the associations between MAFLD and other conditions. It discusses the heightened mortality risk associated with MAFLD and its link to chronic kidney disease (CKD), showing that MAFLD exhibits enhanced diagnostic accuracy for identifying patients with CKD compared to NAFLD. The association between MAFLD and incident/prevalent CKD is supported by cohort studies and meta-analyses.

Conclusion

This literature review highlights the importance of MAFLD as a distinct terminology for fatty liver disease associated with metabolic dysfunction. The review provides insights into the diagnostic criteria, associations with CKD, and management approaches for MAFLD. Further research is needed to develop more accurate diagnostic tools for advanced fibrosis in MAFLD and to explore the underlying mechanisms linking MAFLD with other conditions. This review serves as a valuable resource for researchers and healthcare professionals seeking a comprehensive understanding of MAFLD.

Mitochondrial Quality Control: Its Role in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease, is characterized by hepatic steatosis and metabolic dysfunction and is often associated with obesity and insulin resistance. Recent research indicates a rapid escalation in MASLD cases, with projections suggesting a doubling in the United States by 2030. This review focuses on the central role of mitochondria in the pathogenesis of MASLD and explores potential therapeutic interventions. Mitochondria are dynamic organelles that orchestrate hepatic energy production and metabolism and are critically involved in MASLD. Dysfunctional mitochondria contribute to lipid accumulation, inflammation, and liver fibrosis. Genetic associations further underscore the relationship between mitochondrial dynamics and MASLD susceptibility. Although U.S. Food and Drug Administration-approved treatments for MASLD remain elusive, ongoing clinical trials have highlighted promising strategies that target mitochondrial dysfunction, including vitamin E, metformin, and glucagon-like peptide-1 receptor agonists. In preclinical studies, novel therapeutics, including nicotinamide adenine dinucleotide+ precursors, urolithin A, spermidine, and mitoquinone, have shown beneficial effects, such as improving mitochondrial quality control, reducing oxidative stress, and ameliorating hepatic steatosis and inflammation. In conclusion, mitochondrial dysfunction is central to MASLD pathogenesis. The innovative mitochondria-targeted approaches discussed in this review offer a promising avenue for reducing the burden of MASLD and improving global quality of life.

From Non-Alcoholic Steatohepatitis (NASH) to Hepatocellular Carcinoma (HCC): Epidemiology, Incidence, Predictions, Risk Factors, and Prevention

Non-alcoholic fatty liver disease (NAFLD) affects up to a quarter of the adult population in many developed and developing countries. This spectrum of liver disease ranges from simple steatosis to non-alcoholic steatohepatitis (NASH) and cirrhosis. The incidence of NASH is projected to increase by up to 56% over the next 10 years. There is growing epidemiological evidence that NAFLD has become the fastest-growing cause of hepatocellular carcinoma (HCC) in industrialized countries. The annual incidence of HCC varies between patients with NASH cirrhosis and patients with noncirrhotic NAFLD. In this review, NAFLD/NASH-associated HCC will be described, including its epidemiology, risk factors promoting hepatocarcinogenesis, and management of HCC in patients with obesity and associated metabolic comorbidities, including preventive strategies and therapeutic approaches to address this growing problem.

Harnessing the Therapeutic Potential of Ginsenoside Rd for Activating SIRT6 in Treating a Mouse Model of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a prevalent global condition and a common precursor to liver cancer, yet there is currently no specific medication available for its treatment. Ginseng, renowned for its medicinal and dietary properties, has been utilized in NAFLD management, although the precise underlying mechanism remains elusive. To investigate the effectiveness of ginsenoside Rd, we employed mouse and cell models to induce NAFLD using high-fat diets, oleic acid, and palmitic acid. We explored and confirmed the specific mechanism of ginsenoside Rd-induced hepatic steatosis through experiments involving mice with a liver-specific knockout of SIRT6, a crucial protein involved in metabolic regulation. Our findings revealed that administration of ginsenoside Rd significantly reduced the inflammatory response, reactive oxygen species (ROS) levels, lipid peroxide levels, and mitochondrial stress induced by oleic acid and palmitic acid in primary hepatocytes, thereby mitigating excessive lipid accumulation. Moreover, ginsenoside Rd administration effectively enhanced the mRNA content of key proteins involved in fatty acid oxidation, with a particular emphasis on SIRT6 and its target proteins. We further validated that ginsenoside Rd directly binds to SIRT6, augmenting its deacetylase activity. Notably, we made a significant observation that the protective effect of ginsenoside Rd against hepatic disorders induced by a fatty diet was almost entirely reversed in mice with a liver-specific SIRT6 knockout. Our findings highlight the potential therapeutic impact of Ginsenoside Rd in NAFLD treatment by activating SIRT6. These results warrant further investigation into the development of Ginsenoside Rd as a promising agent for managing this prevalent liver disease.

Clinical characteristics and management of patients with nonalcoholic steatohepatitis in a real-world setting: analysis of the Ipsos NASH therapy monitor database

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is the more severe, inflammatory type of nonalcoholic fatty liver disease (NAFLD). NASH, a leading indication for liver transplantation, is growing in prevalence. The extent of liver fibrosis, ranging from fibrosis stage (FS) of none (F0) to cirrhosis (F4), is a strong predictor of health outcomes. There is little information on patient demographics and clinical characteristics by fibrosis stage and NASH treatment outside of academic medical centers.

METHODS

We conducted a cross-sectional observational study using Ipsos' syndicated NASH Therapy Monitor database, consisting of medical chart audits provided by sampled NASH-treating physicians in the United States in 2016 (n = 174) and 2017 (n = 164). Data was collected online.

RESULTS

Of 2,366 patients reported on by participating physicians and included in the analysis, 68% had FS F0-F2, 21% had bridging fibrosis (F3), and 9% had cirrhosis (F4). Common comorbidities were type 2 diabetes (56%), hyperlipidemia (44%), hypertension (46%), and obesity (42%). Patients with more advanced fibrosis scores (F3-F4) had higher comorbidity rates than patients with F0-F2. Commonly used diagnostic tests included ultrasound (80%), liver biopsy (78%), AST/ALT ratio (43%), NAFLD fibrosis score (25%), transient elastography (23%), NAFLD liver fat score (22%), and Fatty Liver Index (19%). Most commonly prescribed medications were vitamin E (53%), statins (51%), metformin (47%), angiotensin converting enzyme inhibitors (28%), and beta blockers (22%). Medications were commonly prescribed for reasons other than their known effects.

CONCLUSION

Physicians in this study, drawn from a spectrum of practice settings, relied on ultrasound and liver biopsy for diagnosis and vitamin E, statins, and metformin for pharmacological treatment of NASH. These findings imply poor adherence to guidelines in the diagnosis and management of NAFLD and NASH. Nonalcoholic steatohepatitis (NASH) is a liver disease caused by excess fat in the liver which can lead to liver inflammation and scarring (fibrosis), ranging from stage F0 (no scarring) to F4 (advanced scarring). The stage of liver scarring can predict the likelihood of future health problems, including liver failure and liver cancer. However, we do not fully understand how patient characteristics may vary at different stages of liver scarring. We looked at medical information from physicians treating patients diagnosed with NASH to understand how patient characteristics might differ based on the severity of their liver scarring. The majority (68%) of patients were stage F0-F2, with 30% having advanced scarring (F3-F4). In addition to NASH, many patients also had type 2 diabetes, high cholesterol, high blood pressure, and obesity. Patients with more advanced scarring (F3-F4) were more likely to have these diseases than patients with less severe disease (F0-F2). Diagnosis of NASH by participating physicians was based on tests including imaging (ultrasound, CT scan, MRI), liver biopsy, blood tests, and whether patients had other conditions that would put them at risk for NASH. The medications that the doctors prescribed most often to their patients included vitamin E and drugs to treat high cholesterol, high blood pressure, or diabetes. Medications were frequently prescribed for reasons other than their known effects. By understanding how patient characteristics vary by stages of liver scarring and how NASH is currently managed may help guide the evaluation and treatment of NASH when NASH-specific therapies become available.

Chinese pediatric and adolescent reference intervals of vitamin E based on real-world physical examination data

OBJECTIVES

To establish the reference interval (RI) of vitamin E for Chinese children and adolescents.

MATERIALS AND METHODS

Serum tocopherol samples were examined using high performance liquid chromatography in third-party clinical laboratory institutions. Using real-world data from multi-center clinical laboratory institutions in China, the distribution parameters of vitamin E levels were described and the RI was calculated using three algorithms.

RESULTS

A total of 756,766 cases were included in the analysis, including 435,561 males and 321,205 females. The median of vitamin E in infants younger than 4 years of age initially increased but subsequently decreased; while its levels in children between 4 and 11 years of age remained relatively stable despite progressing in age (approximately 7.4-7.8 mg/L). After the start of puberty, the difference, relative to sex, gradually became apparent, and the median vitamin E levels in females was higher than in males. The differences of vitamin E levels between different regions and samples in different seasons had no clinical significance. The RI of vitamin E for children aged 0-18 years in China was 4.5-11.1 mg/L based on expectation-maximization algorithm. The RI established by the Hoffmann method was 4.6-12.8 mg/L.

CONCLUSION

The age- and sex-specific RIs of vitamin E were established by an indirect approach. The RIs established by EM algorithms could be used as an alternative to establish RIs based on real-world data.

Application of regulation of reactive oxygen species and lipid peroxidation to disease treatment

Although many diseases in which reactive oxygen species (ROS) and free radicals are involved in their pathogenesis are known, and antioxidants that effectively capture ROS have been identified and developed, there are only a few diseases for which antioxidants have been used for treatment. Here, we discuss on the following four concepts regarding the development of applications for disease treatment by regulating ROS, free radicals, and lipid oxidation with the findings of our research and previous reports. Concept 1) Utilization of antioxidants for disease treatment. In particular, the importance of the timing of starting antioxidant will be discussed. Concept 2) Therapeutic strategies using ROS and free radicals. Methods of inducing ferroptosis, which has been advocated as an iron-dependent cell death, are mentioned. Concept 3) Treatment with drugs that inhibit the synthesis of lipid mediators. In addition to the reduction of inflammatory lipid mediators by inhibiting cyclooxygenase and leukotriene synthesis, we will introduce the possibility of disease treatment with lipoxygenase inhibitors. Concept 4) Disease treatment by inducing the production of useful lipid mediators for disease control. We describe the treatment of inflammatory diseases utilizing pro-resolving mediators and propose potential compounds that activate lipoxygenase to produce these beneficial mediators.

Risk Prevention and Health Promotion for Non-Alcoholic Fatty Liver Diseases (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a serious clinicopathological condition that is recognized as the most frequent chronic liver disease, affecting 14–30% of the world’s population. The prevalence of NAFLD has rapidly grown and is correlated with the growth in obesity and type 2 diabetes, among other factors. NAFLD often results in long-term complications including cardiovascular disease, liver cirrhosis, and liver fibrosis. This paper provides an updated overview of NAFLD with a focus on epidemiology, etiology, pathophysiology, screening, complications, and pharmacological therapies to identify effective risk prevention and health promotion.

Targeted therapeutics and novel signaling pathways in non-alcohol-associated fatty liver/steatohepatitis (NAFL/NASH)

Non-alcohol-associated fatty liver/steatohepatitis (NAFL/NASH) has become the leading cause of liver disease worldwide. NASH, an advanced form of NAFL, can be progressive and more susceptible to developing cirrhosis and hepatocellular carcinoma. Currently, lifestyle interventions are the most essential and effective strategies for preventing and controlling NAFL without the development of fibrosis. While there are still limited appropriate drugs specifically to treat NAFL/NASH, growing progress is being seen in elucidating the pathogenesis and identifying therapeutic targets. In this review, we discussed recent developments in etiology and prospective therapeutic targets, as well as pharmacological candidates in pre/clinical trials and patents, with a focus on diabetes, hepatic lipid metabolism, inflammation, and fibrosis. Importantly, growing evidence elucidates that the disruption of the gut-liver axis and microbe-derived metabolites drive the pathogenesis of NAFL/NASH. Extracellular vesicles (EVs) act as a signaling mediator, resulting in lipid accumulation, macrophage and hepatic stellate cell activation, further promoting inflammation and liver fibrosis progression during the development of NAFL/NASH. Targeting gut microbiota or EVs may serve as new strategies for the treatment of NAFL/NASH. Finally, other mechanisms, such as cell therapy and genetic approaches, also have enormous therapeutic potential. Incorporating drugs with different mechanisms and personalized medicine may improve the efficacy to better benefit patients with NAFL/NASH.

Screening Potential Drugs for the Development of NAFLD Based on Drug Perturbation Gene Set

Nonalcoholic fatty liver disease (NAFLD) has become one of the problems affecting the health of the population worldwide. The progressive disease includes nonalcoholic steatohepatitis (NASH) and fibrosis, which with no approved therapy, system identification of effective drugs remains challenging. In this work, we applicated drug perturbation gene set enrichment analysis to screen drugs for the development of NAFLD. A total 15490 small-molecule compounds were analyzed in our study; based on the p value of enrichment score, 7 small-molecule compounds were found to have a potential role in NASH and fibrosis. After pathway analyses, we found indoximod had effects on nonalcoholic fatty liver disease through regulated TNFa, AP-1, AKT, PI3K, etc. Furthermore, we established the NAFLD cell model with LO2 cells induced using PA; ELISA showed that the levels of TG, ALT, and AST were significantly improved by indoximod. In summary, our study offers optimal therapeutic drugs, which may provide novel insight into the precise treatment of NAFLD and promote researches.