Role of Dietary Fructose and Hepatic De Novo Lipogenesis in Fatty Liver Disease

Fructose-induced progression of steatohepatitis involves disrupting aldolase B-AMPK signaling in methionine adenosyltransferase 1A deficient mice

OBJECTIVE

Aldolases (ALDO) are sensors that regulate AMPK via binding to fructose 1,6-biphosphate (FBP), an intermediate of glucose and fructose metabolism. Fructose consumption is linked to metabolic dysfunction-associated steatotic liver disease (MASLD) progression but whether ALDO-AMPK signaling is involved is unknown. Methionine adenosyltransferase alpha 1 (Mat1a) knockout (KO) mice have low hepatic S-adenosylmethionine (SAMe) level and spontaneously develop steatohepatitis. ALDOB methylation has not been reported and here we investigated whether SAMe level regulates ALDOB and ALDOB-AMPK signaling and whether fructose feeding accelerates MASLD progression by disrupting ALDOB-AMPK signaling.

METHODS

Mass spectrometry identified ALDOB methylation sites and recombinant in vitro approaches assessed how methylation at those sites affects ALDOB oligomerization and activity. Primary hepatocytes cultured with high/low glucose and/or fructose and wild type (WT) and Mat1a KO mice fed with a high-fructose diet examined AMPK-ALDOB signaling and MASLD progression.

RESULTS

In Mat1a KO livers ALDOB R173 is hypomethylated while ALDOB activity is enhanced. Recombinant ALDOB is methylated at R173 and R304 by protein arginine methyltransferase 1. Low hepatic SAMe level results in hypomethylated ALDOB, which favors the tetrameric form that has higher enzymatic activity, and higher capacity to signal to activate AMPK. Fructose, independently of glucose levels, inhibited AMPK activity and induced lipid accumulation in hepatocytes. Mat1a KO mice have hyperactivated AMPK and fructose feeding inhibits it, enhancing the accumulation of fat in the liver and the progression of MASLD.

CONCLUSION

Hepatic SAMe levels regulate ALDOB oligomeric state and enzymatic activity impacting on AMPK signaling and fructose-induced MASLD progression.

Mitochondrial targeted therapies in MAFLD

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a clinical-pathological syndrome primarily characterized by excessive accumulation of fat in hepatocytes, independent of alcohol consumption and other well-established hepatotoxic agents. Mitochondrial dysfunction is widely acknowledged as a pivotal factor in the pathogenesis of various diseases, including cardiovascular diseases, cancer, neurodegenerative disorders, and metabolic diseases such as obesity and obesity-associated MAFLD. Mitochondria are dynamic cellular organelles capable of modifying their functions and structures to accommodate the metabolic demands of cells. In the context of MAFLD, the excess production of reactive oxygen species induces oxidative stress, leading to mitochondrial dysfunction, which subsequently promotes metabolic disorders, fat accumulation, and the infiltration of inflammatory cells in liver and adipose tissue. This review aims to systematically analyze the role of mitochondria-targeted therapies in MAFLD, evaluate current therapeutic strategies, and explore future directions in this rapidly evolving field. We specifically focus on the molecular mechanisms underlying mitochondrial dysfunction, emerging therapeutic approaches, and their clinical implications. This is of significant importance for the development of new therapeutic approaches for these metabolic disorders.

A murine model of obesity with hyperinsulinemia and hepatic steatosis involving neurosecretory protein GL gene and a low-fat/medium-sucrose diet

Metabolic dysfunction-associated steatotic liver disease (MASLD) featuring hepatic steatosis and insulin dysregulation is becoming a common cause of chronic hepatic diseases. Although the involvement of endocrine disruption in the onset and progression of MASLD is thought to be critical, there are limited effective animal models reflecting hyperinsulinemia and hepatic steatosis. Here, we propose a MASLD mouse model that combines neuropeptide effects and dietary nutrition. We employed chronic overexpression of the gene encoding neurosecretory protein GL (NPGL) in the hypothalamus of ICR mice under a low-fat/medium-sucrose diet (LFMSD). Npgl overexpression promoted fat accumulation in the white adipose tissues in 2 weeks. Basal insulin levels were increased and pancreatic islets expanded following Npgl overexpression. Histological and molecular biological approaches revealed that Npgl overexpression enhanced de novo lipogenesis, leading to hepatic steatosis. Nine-week overexpression of Npgl exacerbated obesity and hyperinsulinemia, resulting in hyperglycemia. Moreover, prolonged Npgl overexpression aggravated fat accumulation in the liver with a change in the lipid metabolic pathway. These findings suggest that Npgl overexpression readily leads to obesity with hyperinsulinemia and hepatic steatosis in ICR mice under an LFMSD.

Honokiol, a neolignan from Magnolia officinalis, attenuated fructose-induced hepatic fat accumulation by improving intestinal barrier function in mice

BACKGROUND

Fructose consumption has been suggested to contribute to metabolic diseases including metabolic dysfunction-associated steatotic liver disease (MASLD), at least in part, by disturbing intestinal barrier function and intestinal nitric oxide (NO) homeostasis. Honokiol, a neolignan found in Magnolia officinalis, has been suggested to affect intestinal integrity and barrier function.

OBJECTIVE

We assessed whether honokiol affects fructose-induced small intestinal permeability in settings of early MASLD.

METHODS

Female 8-10 weeks old C57BL/6J mice (n=7/group) received either a 30% fructose solution + vehicle (Fru) or plain drinking water + vehicle ± honokiol (Hon, 10 mg/kg bw/day) for four weeks. Liver damage (e.g., NAFLD activity score (NAS), number of neutrophils, interleukin-6 (IL6) protein concentration), markers of intestinal permeability (bacterial endotoxin, tight junction proteins), and NO homeostasis in small intestine were determined in vivo as well as ex vivo in an everted sac model and in Caco-2 cells. One-way and two-way ANOVA were performed, respectively.

RESULTS

Honokiol diminished the development of MASLD, which was associated with a significant lower NAS (-38%), number of neutrophils (-48%) and IL6 protein concentrations (-38%) in livers of Fru-fed mice. Honokiol also attenuated fructose-induced alterations of markers of intestinal barrier function with Fru+Hon-fed mice showing lower bacterial toxin levels in portal plasma (-29%, p=0.075), higher tight junction protein concentrations (+2.4-fold, p<0.05), and lower NOx concentration (-44%, p<0.05) as well as NOS activity (-35%) in the small intestine compared to Fru+vehicle-fed mice. Moreover, the decrease in AMPK phosphorylation found in small intestine of Fru-fed mice was significantly attenuated (+5.3-fold) by the concomitant treatment with honokiol in Fru-fed mice. In support of the in vivo findings, honokiol significantly attenuated Fru-induced intestinal permeability ex vivo and in Caco-2 cells.

CONCLUSIONS

Our data suggest that honokiol diminished the development of fructose-induced early MASLD by alleviating impairments in intestinal barrier function.

The role of dietary sugars in cancer risk: A comprehensive review of current evidence

GOAL OF THE REVIEW

The objective of this review is to conduct a thorough examination of the current evidence regarding the correlation between dietary sugar intake and cancer risk. This will encompass the biological mechanisms, the diverse effects of various sugar types, and the potential implications for cancer treatment and dietary recommendations.

INTRODUCTION

Nutritional and epidemiological studies now focus much on the relationship between sugar intake and cancer. The data is still conflicting even if some studies imply that excessive sugar intake can help cancer develop by means of insulin resistance and chronic inflammation.

DISCUSSION

Through processes such as insulin resistance, inflammation, and angiogenesis, dietary sugars can impact carcinogenesis. Fructose increases angiogenesis by VEGF overexpression while glucose stimulates cancer cell growth by the Warburg effect. Contradicting data on the contribution of sugar to cancer emphasizes the need of consistent research techniques to simplify these dynamics. Reducing added sugar consumption in cancer prevention and management is especially crucial given that sugar affects immune function and treatment resistance, which could lead to new therapeutic targets.

CONCLUSION

High sugar intake is linked to mechanisms such as the Warburg effect, insulin resistance, and chronic inflammation, which may contribute to cancer risk under specific conditions. However, the evidence is not universally conclusive, and additional large-scale, long-term research are required to better understand these processes. To help in cancer prevention and management, public health guidelines should emphasize reducing added sugar consumption and promoting a balanced diet rich in natural foods.

Proline enhances the hepatic induction of lipogenic gene expression in male hepatic fasn reporter mice

Hepatic de novo lipogenesis (DNL) is increased by both carbohydrate intake and protein consumption. In hepatic fat synthesis, a key role is played by the induction of the hepatic expression of lipogenic genes, including Fasn, Scd1, and Srebf1. Regarding carbohydrate intake, increased blood glucose and insulin levels promote the expression of hepatic lipogenic genes. However, although amino acids serve as a carbon source for hepatic DNL during protein consumption, their effects on hepatic lipogenic gene expression remain unclear. We investigated the effects of amino acids on hepatic lipogenic gene induction using primary cultured mouse hepatocytes and hepatic Fasn reporter (l-FasnGLuc) mice. In primary cultured hepatocytes, lipogenic gene expression (Fasn, Scd1, Srebf1) was induced under postprandial-mimicking conditions (treatment with insulin and LXR agonist). When hepatocytes were stimulated with an amino acid mixture containing 20 amino acids, the induction of lipogenic gene expression was enhanced, but this effect disappeared when proline was removed from the mixture. Furthermore, when each amino acid was tested individually, only proline potentiated the induction of lipogenic gene expression in hepatocytes under postprandial-mimicking conditions. In mouse liver, continuous proline infusion via osmotic pump increased Fasn gene expression and showed a trend toward increased Srebf1 expression. In l-FasnGLuc mice, continuous proline infusion resulted in sustained enhancement of hepatic Fasn transcription, measured by secreted luciferase activity. These results demonstrate that proline enhances the induction of hepatic lipogenic gene expression both in vitro and in vivo.

MASH as an emerging cause of hepatocellular carcinoma: current knowledge and future perspectives

Hepatocellular carcinoma is one of the deadliest and fastest-growing cancers. Among HCC etiologies, metabolic dysfunction-associated fatty liver disease (MAFLD) has served as a major HCC driver due to its great potential for increasing cirrhosis. The obesogenic environment fosters a positive energy balance and results in a continuous rise of obesity and metabolic syndrome. However, it is difficult to understand how metabolic complications lead to the poor prognosis of liver diseases and which molecular mechanisms are underpinning MAFLD-driven HCC development. Thus, suitable preclinical models that recapitulate human etiologies are essentially required. Numerous preclinical models have been created but not many mimicked anthropometric measures and the course of disease progression shown in the patients. Here we review the literature on adipose tissues, liver-related HCC etiologies and recently discovered genetic mutation signatures found in MAFLD-driven HCC patients. We also critically review current rodent models suggested for MAFLD-driven HCC study.

Revisiting the concepts of de novo lipogenesis to understand the conversion of carbohydrates into fats: Stop overvaluing and extrapolating the renowned phrase "fat burns in the flame of carbohydrate"

Carbohydrates can be converted into fatty acids via de novo lipogenesis (DNL). Although DNL is considered inefficient, these endogenous fatty acids contribute substantially to the esterification pathway in adipose tissue, together with fatty acids of feeding. This article revisited the concepts of DNL and aimed to discuss the clinical magnitude of carbohydrate overfeeding and fat mass accumulation. Although fat storage resulting from fat intake is more favorable for fat mass accrual than carbohydrates due to molecule structure and metabolism (e.g., oxidation and thermic effect), carbohydrates can substantially participate in lipogenesis and esterification under excess carbohydrate intake over time. Regarding only monosaccharide overfeeding, glucose and fructose favor the subcutaneous and visceral adipose tissue, respectively. While fructose and sucrose are considered villains in nonalcoholic fatty liver disease, energy surplus from carbohydrates, regardless of sources, can be considered an underlying cause of obesity. Interestingly, some degree of DNL in adipocytes may be favorable to mitigate a high deposition of fatty acids in the liver, conferring a physiological role. Although "fat burns in the flame of carbohydrate" is a praiseworthy phrase that has helped describe basic concepts in biochemistry for many decades, it appears to be overvalued and extrapolated even nowadays. DNL cannot be neglected. It is time to consider DNL an efficient biochemical process in health and disease.

Resveratrol: A Narrative Review Regarding Its Mechanisms in Mitigating Obesity-Associated Metabolic Disorders

Resveratrol (RSV) is a naturally occurring astragalus-like polyphenolic compound with remarkable weight loss properties. However, the mechanism of RSV in treating obesity is unclear. In this narrative review, we explored electronic databases (PubMed) for research articles from 2021 to the present using the keywords "resveratrol" and "obesity". This article explores the mechanisms involved in the alleviation of obesity-related metabolic disorders by RSV. RSV affects obesity by modulating mitochondrial function, insulin signaling, and gut microbiota, regulating lipid metabolism, inhibiting oxidative stress, and regulating epigenetic regulation. Administering RSV to pregnant animals exhibits maternal and first-generation offspring benefits, and RSV administration to lactating animals has long-term benefits, which involve the epigenetic modulations by RSV. A comprehensive understanding of the epigenetic mechanisms of RSV regulation could help in developing drugs suitable for pregnancy preparation groups, pregnant women, and nursing infants.

Hu-lu-su-pian ameliorates hepatic steatosis by regulating CIDEA expression in AKT-driven MASLD mice

Introduction

Hu-lu-su-pian (HLSP) is an oral tablet derived from the active compounds of Cucumis melo L., a traditional Chinese medicine. This contemporary formulation is frequently employed in clinical settings for the management of liver ailments. However, the molecular mechanism by which HLSP affects metabolic dysfunction-associated steatotic liver disease (MASLD) remains unclear. This study aimed to explore the therapeutic potential of HLSP on MASLD and the underlying mechanism.

Methods

The researchers used ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) to identify the primary chemical components of HLSP. A mouse model of MASLD induced by AKT was established through hydrodynamic transfection with activated forms of AKT. Serum biochemical indices and liver pathological assessments were employed to evaluate the pharmacodynamic effects of HLSP on MASLD. Transcriptomic analysis of the liver was conducted to detect differentially expressed genes (DEGs). Further examination of significant DEGs and proteins was performed using quantitative real-time polymerase chain reaction (RT-qPCR), Western blotting, and immunohistochemistry (IHC) techniques, respectively. The efficacy and molecular mechanisms of HLSP in MASLD were further explored in HepG2 and Huh-7 cells in the presence of gene overexpression.

Results

From the UPLC-Q-TOF-MS/MS results, we detected fifteen components from HLSP. From the results of serum biochemical indices and hepatic pathology analyses, it is clear that HLSP is effective in treating MASLD. The findings from hepatic transcription studies revealed CIDEA as an essential DEG that facilitates lipid droplet (LD) fusion and enhances de novo fatty acid synthesis from scratch in cases of hepatic steatosis, which HLSP has the potential to counteract. In addition, HLSP significantly reduced lipid accumulation and expression of critical genes for de novo fatty acid synthesis in HepG2 and Huh-7 cells overexpressing CIDEA.

Discussion

The present study preliminarily suggests that HLSP can ameliorate hepatic steatosis by inhibiting CIDEA-mediated de novo fatty acid synthesis and LD formation, which may offer a potential strategy for treating MASLD.

Consuming pecans as a snack improves lipids/lipoproteins and diet quality compared with usual diet in adults at increased risk of cardiometabolic diseases: a randomized controlled trial

BACKGROUND

The vascular and cardiometabolic effects of pecans are relatively understudied.

OBJECTIVES

The aim was to examine how substitution of usual snack foods with 57 g/d of pecans affects vascular health, risk factors for cardiometabolic diseases, and diet quality, compared with continuing usual intake in individuals at risk of cardiometabolic diseases.

METHODS

A 12-wk single-blinded, parallel, randomized controlled trial was conducted. Adults with ≥1 criterion for metabolic syndrome who were free from cardiovascular disease and type 2 diabetes were included. Participants were provided with 57 g/d of pecans and instructed to replace the snacks usually consumed with the provided pecans. The control group was instructed to continue consuming their usual diet. Flow-mediated dilation (FMD),primary outcome, along with blood pressure, carotid-femoral pulse wave velocity (cf-PWV), lipids/lipoproteins, and glycemic control were measured at baseline and following the intervention. Participants completed 3 24-h recalls at 3 time points (baseline, week 6, and week 12) during the study (9 recalls in total). The Healthy Eating Index-2020 (HEI-2020) was calculated to assess diet quality.

RESULTS

In total, 138 participants (mean ± SD; 46 ± 13 y, 29.8 ± 3.7 kg/m2) were randomly assigned (69 per group). No between-group differences in FMD, cf-PWV, or blood pressure were observed. Compared with the usual diet group, pecan intake reduced total cholesterol (-8.1 mg/dL; 95% confidence interval [CI]: -14.5, -1.7), LDL cholesterol (-7.2 mg/dL; 95% CI -12.3, -2.1), non-HDL-cholesterol (-9.5 mg/dL; 95% CI -15.3, -3.7), and triglycerides concentrations (-16.4 mg/dL; 95% CI -30.0, -2.9). Weight tended to increase in the pecan group compared with the usual diet group (0.7 kg; 95% CI -0.1, 1.4). The HEI-2020 increased by 9.4 points (95% CI 5.0, 13.7) in the pecan group compared with the usual diet group.

CONCLUSIONS

Replacing usual snacks with 57 g/d of pecans for 12-wk improves lipids/lipoproteins and diet quality but does not affect vascular health in adults at risk of cardiometabolic disease. This trial was registered at clinicaltrials.gov as NCT05071807.

Characteristics of different lipid droplet-mitochondrial contacts patterns during lipid droplet metabolism in T2DM-induced MASLD

Mitochondrial function is crucial for hepatic lipid metabolism. Current research identifies two types of mitochondria based on their contact with lipid droplets: peridroplet mitochondria (PDM) and cytoplasmic mitochondria (CM). This work aimed to investigate the alterations of CM and PDM in metabolic dysfunction-associated steatotic liver disease (MASLD) induced by spontaneous type-2 diabetes mellitus (T2DM) in db/db mice. It was found that insulin resistance increased both the number and size of lipid droplets in the liver by enhancing the accumulation of free fatty acids, which is accompanied by an increase in contacts with mitochondria. We described the different patterns of tight contacts between small lipid droplets and mitochondria in purified CM and PDM by examining their oxidation states and morphological characteristics. In CM, enhanced fatty acid oxidation resulted in elongated mitochondria that surrounded single small lipid droplets and were responsible for lipid droplet consumption, while in PDM, increased substrates for lipid synthesis promoted lipid droplet expansion with the assistance of the endoplasmic reticulum. These data show the different ways in which mitochondrial contact with lipid droplets could provide new insights for future research on liver lipid metabolism.

Association of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Coffee Consumption with Chronic Liver Disease and Liver-Related Events: A Large Prospective Cohort Study

BACKGROUND

Previous observational studies have not reached an agreement on the association between coffee consumption and risk of liver diseases. Also, none of these studies took sweetener added in coffee into consideration.

OBJECTIVES

We aim to explore the associations of consumption of sweetened and unsweetened coffee with chronic liver disease (CLD) and liver-related events (LREs), and evaluate the degree to which sweetener added counteracted the effect of coffee.

METHODS

We performed a longitudinal cohort study of 170,044 participants without liver diseases or cancer at baseline investigation (2006-2010) and followed until 2022. Consumption of coffee and sweetener was assessed by 24-h dietary recall questionnaire. Cox proportional hazards models and restricted cubic splines were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During a median follow-up of 12.4 y, we identified 4152 incident of CLD and 853 LREs. Compared with nonconsumers, unsweetened coffee consumers of various amount had lower risk of CLD (HR: 0.75; 95% CI: 0.67, 0.83 for 1.5∼2.5 drinks/d) and LREs (HR: 0.60; 95% CI: 0.46, 0.80 for 2.5∼3.5 drinks/d) in the multivariable Cox models. U-shaped associations of unsweetened coffee with CLD and LREs were observed. The results for sweetened coffee were less consistent and conclusive in both CLD and LREs. We detected positive associations between sweetener and CLD and LREs. Compared with unsweetened coffee consumers, consumers of different amount of sugar added to coffee had higher risk of CLD in the multivariable Cox model. For artificial sweetener, a significant higher risk of CLD (HR: 1.61; 95% CI: 1.25, 2.05)and LREs (HR: 1.82; 95% CI: 1.11, 2.98) was only found in those who added ≥2 teaspoons/drink. We detected significant interaction between artificial sweetener and coffee intake on the risk of CLD (HR for product term: 0.76; 95% CI: 0.60, 0.96; P = 0.018; relative excess risk due to interaction: -0.32; 95% CI: -0.58, -0.06).

CONCLUSIONS

Moderate consumption of unsweetened coffee was associated with lower risk of CLD and LREs. Adding sweetener into coffee could bring additional risk of liver diseases in coffee consumers.

The impact of solute carrier proteins on disrupting substance regulation in metabolic disorders: insights and clinical applications

Carbohydrates, lipids, bile acids, various inorganic salt ions and organic acids are the main nutrients or indispensable components of the human body. Dysregulation in the processes of absorption, transport, metabolism, and excretion of these metabolites can lead to the onset of severe metabolic disorders, such as type 2 diabetes, non-alcoholic fatty liver disease, gout and hyperbilirubinemia. As the second largest membrane receptor supergroup, several major families in the solute carrier (SLC) supergroup have been found to play key roles in the transport of substances such as carbohydrates, lipids, urate, bile acids, monocarboxylates and zinc ions. Based on common metabolic dysregulation and related metabolic substances, we explored the relationship between several major families of SLC supergroup and metabolic diseases, providing examples of drugs targeting SLC proteins that have been approved or are currently in clinical/preclinical research as well as SLC-related diagnostic techniques that are in clinical use or under investigation. By highlighting these connections, we aim to provide insights that may contribute to the development of improved treatment strategies and targeted therapies for metabolic disorders.

Gut Microbiota at the Crossroad of Hepatic Oxidative Stress and MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent chronic liver condition marked by excessive lipid accumulation in hepatic tissue. This disorder can lead to a range of pathological outcomes, including metabolic dysfunction-associated steatohepatitis (MASH) and cirrhosis. Despite extensive research, the molecular mechanisms driving MASLD initiation and progression remain incompletely understood. Oxidative stress and lipid peroxidation are pivotal in the "multiple parallel hit model", contributing to hepatic cell death and tissue damage. Gut microbiota plays a substantial role in modulating hepatic oxidative stress through multiple pathways: impairing the intestinal barrier, which results in bacterial translocation and chronic hepatic inflammation; modifying bile acid structure, which impacts signaling cascades involved in lipidic metabolism; influencing hepatocytes' ferroptosis, a form of programmed cell death; regulating trimethylamine N-oxide (TMAO) metabolism; and activating platelet function, both recently identified as pathogenetic factors in MASH progression. Moreover, various exogenous factors impact gut microbiota and its involvement in MASLD-related oxidative stress, such as air pollution, physical activity, cigarette smoke, alcohol, and dietary patterns. This manuscript aims to provide a state-of-the-art overview focused on the intricate interplay between gut microbiota, lipid peroxidation, and MASLD pathogenesis, offering insights into potential strategies to prevent disease progression and its associated complications.

How the liver transcriptome and lipid composition influence the progression of nonalcoholic fatty liver disease to hepatocellular carcinoma in a murine model

The incidence of nonalcoholic fatty liver disease (NAFLD) has been steadily increasing in Western society in recent years and has been recognized as a risk factor for the development of hepatocellular carcinoma (HCC). However, the molecular mechanisms underlying the progression from NAFLD to HCC are still unclear, despite the use of suitable mouse models. To identify the transcriptional and lipid profiles of livers from mice with NAFLD-HCC, we induced both NAFLD and NAFLD-HCC pathologies in C57BL/6J mice and performed RNA-sequencing (RNA-seq) and targeted lipidomic analysis. Our RNA-seq analysis revealed that the transcriptional signature of NAFLD in mice is characterized by changes in inflammatory response and fatty acid metabolism. Moreover, the signature of NAFLD-HCC is characterized by processes typically observed in cancer, such as epithelial to mesenchymal transition, angiogenesis and inflammatory responses. Furthermore, we found that the diet used in this study inhibited cholesterol synthesis in both models. The analysis of lipid composition also showed a significant impact of the provided diet. Therefore, our study supports the idea that a Western diet (WD) affects metabolic processes and hepatic lipid composition. Additionally, the combination of a WD with the administration of a carcinogen drives the progression from NAFLD to HCC.

Fructose Consumption in Pregnancy and Associations with Maternal and Offspring Hepatic and Whole-Body Adiposity in Rodents: A Scoping Review

Background

Excess fructose consumption has been linked to adverse metabolic health, including impaired hepatic function and increased adiposity. The early life period, including preconception, pregnancy, and the newborn period, are critical periods in determining later metabolic health. However, the impact of excess fructose intake during this time on maternal, fetal, and offspring hepatic and whole-body adiposity, is not well defined.

Objectives

To understand the effects of maternal fructose consumption pre- and during pregnancy on maternal, fetal, and offspring hepatic and whole-body adiposity.

Methods

A systematic search of MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials was performed up to October 4, 2024, to identify animal and human studies that focused on maternal fructose consumption pre- and during pregnancy on hepatic and whole-body adiposity in the mother, fetus, and offspring. Citations, abstracts, and full texts were screened in duplicate. Hepatic adiposity was defined as elevated hepatic triglycerides or overall hepatic lipid accumulation. Whole-body adiposity was defined as increased adipose tissue, serum lipids, or adipocyte hypertrophy.

Results

After screening 2538 citations, 37 experimental rodent studies reporting maternal fructose consumption pre- and during pregnancy in rodents were included. No human studies met the inclusion criteria. Prenatal fructose exposure was associated with maternal (9 of 12) and offspring (7 of 11) whole-body adiposity. A high proportion of studies (13 of 14) supported the association between fructose during pregnancy and increased maternal hepatic adiposity. Fetal hepatic adiposity and elevated expression of hepatic lipogenic proteins were noted in 4 studies. Offspring hepatic adiposity was supported in 16 of the 20 articles that discussed hepatic results, with 5 studies demonstrating more severe effects in female offspring.

Conclusions

Fructose consumption during pregnancy in rodent models is associated with maternal, fetal, and offspring hepatic and whole-body adiposity with underlying sex-specific effects. No human studies met the inclusion criteria.

Registration number

H8F26 on Open Science Framework (https://doi.org/10.17605/OSF.IO/H8F26).

Female C57BL/6 mice exhibit protection against nonalcoholic fatty liver disease and diabesity accompanied by differential regulation of hepatic lipocalin prostaglandin D2 synthase

Nonalcoholic fatty liver disease (NAFLD) and its development into nonalcoholic steatohepatitis (NASH) are challenging health concerns globally. Clinically, the prevalence and severity of NAFLD/NASH are higher in men than in premenopausal women. NAFLD is strongly correlated with obesity, both of which are tied to high-fat/fructose-rich western diets. Therefore, we aimed to investigate sexual dimorphism in NAFLD pathogenesis in male and female C57BL/6 mice fed different diets. Male and female C57BL/67 mice were divided into four groups and kept on a chow (C), chow plus high fructose (CF), high fat (HF), and high fat plus high fructose (HFF) diet for 22 weeks. Liver tissues were collected at the end of the study and processed for NAFLD/NASH-related histology (H&E and trichrome staining), protein expression (SREBP1, SCAP, FABP4, α-SMA, TGF-β and L-PGDS), and biochemical parameters measurement. Our results displayed that female mice exhibited protection against NAFLD and diabesity on HF and HFF diets compared to male mice fed similar diets. Additionally, female mice showed protection from fibrosis compared to male mice. Both male and female mice fed HF and HFF diet groups displayed the cytosol-to-nuclear translocation of Lipocalin Prostaglandin D2 Synthase (L-PGDS). Cytoplasmic levels of L-PGDS were absent in females compared to low levels in males, revealing a possible sex-specific mechanism tied to fructose and fat metabolism. Collectively, female mice showed protection against NAFLD and diabesity relative to male mice, accompanied by differential regulation of hepatic lipocalin prostaglandin D2 synthase.

Fructose-Induced Metabolic Dysfunction Is Dependent on the Baseline Diet, the Length of the Dietary Exposure, and Sex of the Mice

Background/Objectives: High sugar intake, particularly fructose, is implicated in obesity and metabolic complications. On the other hand, fructose from fruits and vegetables has undisputed benefits for metabolic health. This raises a paradoxical question-how the same fructose molecule can be associated with detrimental health effects in some studies and beneficial in others. This study investigates how diet and sex interact with fructose to modulate the metabolic outcomes. Methods: Male and female mice were fed different normal chow diets, Boston chow diet (BCD; 23% protein, 22% fat, 55% carbohydrates), Lexington chow diet (LXD; 24% protein, 18% fat, 58% carbohydrates), and low-fat diet (LFD; 20% protein, 10% fat, 70% carbohydrates), supplemented with 30% fructose in water. Results: Fructose-supplemented male mice on BCD gained weight and developed glucose intolerance and hepatic steatosis. Conversely, male mice given fructose on LXD did not gain weight, remained glucose-tolerant, and had normal hepatic lipid content. Furthermore, fructose-fed male mice on LFD did not gain weight. However, upon switching to BCD, they gained weight, exhibited worsening liver steatosis, and advanced hepatic insulin resistance. The effects of fructose are sex-dependent. Thus, female mice did not gain weight and remained insulin-sensitive with fructose supplementation on BCD, despite developing hepatic steatosis. These differences in metabolic outcomes correlate with the propensity of the baseline diet to suppress hepatic ketohexokinase expression and the de novo lipogenesis pathway. This is likely driven by the dietary fat-to-carbohydrate ratio. Conclusions: Metabolic dysfunction attributed to fructose intake is not a universal outcome. Instead, it depends on baseline diet, dietary exposure length, and sex.

Knockdown of RASD1 improves MASLD progression by inhibiting the PI3K/AKT/mTOR pathway

BACKGROUND

There is still no reliable therapeutic targets and effective pharmacotherapy for metabolic dysfunction-associated steatotic liver disease (MASLD). RASD1 is short for Ras-related dexamethasone-induced 1, a pivotal factor in various metabolism processes of Human. However, the role of RASD1 remains poorly illustrated in MASLD. Therefore, we designed a study to elucidate how RASD1 could impact on MASLD as well as the mechanisms involved.

METHODS

The expression level of RASD1 was validated in MASLD. Lipid metabolism and its underlying mechanism were investigated in hepatocytes and mice with either overexpression or knockdown of RASD1.

RESULTS

Hepatic RASD1 expression was upregulated in MASLD. Lipid deposition was significantly reduced in RASD1-knockdown hepatocytes and mice, accompanied by a marked downregulation of key genes in the signaling pathway of de novo lipogenesis. Conversely, RASD1 overexpression in hepatocytes had the opposite effect. Mechanistically, RASD1 regulated lipid metabolism in MASLD through the PI3K/AKT/mTOR signaling pathway.

CONCLUSIONS

We discovered a novel role of RASD1 in MASLD by regulating lipogenesis via the PI3K/AKT/mTOR pathway, thereby identifying a potential treatment target for MASLD.

Glycerol-3-phosphate activates ChREBP, FGF21 transcription and lipogenesis in Citrin Deficiency

Citrin Deficiency (CD) is caused by inactivation of SLC25A13, a mitochondrial membrane protein required to move electrons from cytosolic NADH to the mitochondrial matrix in hepatocytes. People with CD do not like sweets. We discovered that SLC25A13 loss causes accumulation of glycerol-3-phosphate (G3P), which activates carbohydrate response element binding protein (ChREBP) to transcribe FGF21, which acts in the brain to restrain intake of sweets and alcohol, and to transcribe key genes of de novo lipogenesis. Mouse and human data establish G3P-ChREBP as a new mechanistic component of the Randle Cycle that contributes to metabolic dysfunction-associated steatotic liver disease (MASLD) and forms part of a system that communicates metabolic states from liver to brain in a manner that alters food and alcohol choices. The data provide a framework for understanding FGF21 induction in varied conditions, suggest ways to develop FGF21-inducing drugs, and drug candidates for both lean MASLD and support of urea cycle function in CD.

Understanding the complex function of gut microbiota: its impact on the pathogenesis of obesity and beyond: a comprehensive review

Obesity is a multifactorial condition influenced by genetic, environmental, and microbiome-related factors. The gut microbiome plays a vital role in maintaining intestinal health, increasing mucus creation, helping the intestinal epithelium mend, and regulating short-chain fatty acid (SCFA) production. These tasks are vital for managing metabolism and maintaining energy balance. Dysbiosis-an imbalance in the microbiome-leads to increased appetite and the rise of metabolic disorders, both fuel obesity and its issues. Furthermore, childhood obesity connects with unique shifts in gut microbiota makeup. For instance, there is a surge in pro-inflammatory bacteria compared to children who are not obese. Considering the intricate nature and variety of the gut microbiota, additional investigations are necessary to clarify its exact involvement in the beginnings and advancement of obesity and related metabolic dilemmas. Currently, therapeutic methods like probiotics, prebiotics, synbiotics, fecal microbiota transplantation (FMT), dietary interventions like Mediterranean and ketogenic diets, and physical activity show potential in adjusting the gut microbiome to fight obesity and aid weight loss. Furthermore, the review underscores the integration of microbial metabolites with pharmacological agents such as orlistat and semaglutide in restoring microbial homeostasis. However, more clinical tests are essential to refine the doses, frequency, and lasting effectiveness of these treatments. This narrative overview compiles the existing knowledge on the multifaceted role of gut microbiota in obesity and much more, showcasing possible treatment strategies for addressing these health challenges.

Differential effects of systemic immune inflammation indices on hepatic steatosis and hepatic fibrosis: evidence from NHANES 1999-2018

BACKGROUND

Several studies have demonstrated that systemic immune inflammation index (SII) has a positive relationship with hepatic steatosis. However, it is lack of system evidence for the correlation between SII and hepatic fibrosis. The objective of this study was to evaluate the relationships between SII and hepatic steatosis or hepatic fibrosis.

METHODS

A cross-sectional analysis was performed from the National Health and Nutrition Examination Survey (NHANES). Fibrosis-4 index (FIB-4), NAFLD fibrosis score (NFS) and hepamet fibrosis score (HFS) were the indicators for hepatic fibrosis; fatty liver index (FLI), NAFLD liver fat score (LFS) and Framingham steatosis index (FSI) were the indicators for hepatic steatosis. Pearson's test, generalized linear model (GLM) and restricted cubic splines (RCS) were used to analyze associations of SII with hepatic fibrosis and hepatic steatosis.

RESULTS

A total of 21,833 participants were enrolled in the study. Pearson's test and GLM revealed that there were negative relationships between SII and hepatic fibrosis (FIB-4, NFS and HFS), while positive relationships between SII and hepatic steatosis (FLI, LFS and FSI). The corresponding β (95%CI) of SII and hepatic fibrosis were - 0.35(-0.46, -0.24), -0.67(-0.71, -0.63) and - 0.10(-0.12, -0.09), respectively. The corresponding β (95%CI) of SII and hepatic steatosis were 6.12(4.75, 7.50), 0.22(0.12, 0.31) and 0.27(0.20, 0.34), respectively. Statistically significant non-linear association were found in SII with hepatic fibrosis and hepatic steatosis in RCS model (all P < 0.001).

CONCLUSION

There was a negative significant association between SII and hepatic fibrosis, while a positive significant association between SII and hepatic steatosis.

Peroxisome Proliferator Activator α Agonist Clofibrate Induces Pexophagy in Coconut Oil-Based High-Fat Diet-Fed Rats

Peroxisomes are crucial for fatty acid β-oxidation in steatosis, but the role of pexophagy-the selective autophagy of peroxisomes-remains unclear. This study investigated the effects of the peroxisome proliferator-activated receptor-α (PPARα) agonist clofibrate on pexophagy in a coconut oil-based high-fat diet (HFD)-induced hepatocarcinogenesis model. Rats were divided into four groups: control, clofibrate, HFD, and HFD with clofibrate. The HFD induced steatosis, along with a 2.4-fold increase in pexophagy receptor NBR1-positive granules in hepatocytes. Clofibrate significantly inhibited HFD-induced steatosis, increasing p62-, LAMP2-, and Pex5-positive granules by 7.5-, 7.2-, and 71.4-fold, respectively, while decreasing NBR1 expression. The effects were associated with peroxisome proliferation and pexophagy in ultrastructural observations and increased levels of Lc3, p62, Pex2, Pex14, Acox1, and Scd1 in gene expression analysis. The results suggested that clofibrate effectively reduced steatosis through combined peroxisome proliferation and pexophagy, though it had a marginal impact on hepatocarcinogenesis in coconut oil-based HFD-fed rats. These findings highlight the utility of PPARα agonists in studying mammalian pexophagy.

Postbiotics for the management of obesity, insulin resistance/type 2 diabetes and NAFLD. Beyond microbial viability

Highly prevalent comorbidities associated with metabolic syndrome, such as abdominal obesity, nonalcoholic fatty liver disease (NAFLD) and insulin-resistance/Type 2 diabetes (IR/T2D) share alterations in gut microbiota composition as a potential triggering factor. Recent studies put the attention in the potential usage of postbiotics (inactivated probiotics) on these metabolic alterations. This review summarizes the current evidence regarding the efficacy of postbiotic administration in both, preclinical and clinical studies, for the management of obesity, NAFLD and IR/T2D. Data from preclinical studies (rodents) suggest that postbiotic administration effectively prevents obesity, whereas clinical studies corroborate these benefits also in overweight/obese subjects receiving inactivated bacteria. As for NAFLD, although preclinical studies indicate that postbiotic administration improves different liver markers, no data obtained in humans have been published so far since all the studies are ongoing clinical trials. Finally, while the administration of inactivated bacteria demonstrated to be a promising approach for the management of IR/T2D in rodents, data from clinical trials indicates that in humans, this approach is more effective on IR than in T2D. In conclusion, the available scientific data indicate that postbiotic administration not only is safer, but also as effective as probiotic administration for the management of obesity associated prevalent metabolic alterations.

Knockdown of ketohexokinase versus inhibition of its kinase activity exert divergent effects on fructose metabolism

Excessive fructose intake is a risk factor for the development of obesity and its complications. Targeting ketohexokinase (KHK), the first enzyme of fructose metabolism, has been investigated for the management of metabolic dysfunction-associated steatotic liver disease (MASLD). We compared the effects of systemic, small molecule inhibitor of KHK enzymatic activity with hepatocyte-specific, N-acetylgalactosamine siRNA-mediated knockdown of KHK in mice on an HFD. We measured KHK enzymatic activity, extensively quantified glycogen accumulation, performed RNA-Seq analysis, and enumerated hepatic metabolites using mass spectrometry. Both KHK siRNA and KHK inhibitor led to an improvement in liver steatosis; however, via substantially different mechanisms, KHK knockdown decreased the de novo lipogenesis pathway, whereas the inhibitor increased the fatty acid oxidation pathway. Moreover, KHK knockdown completely prevented hepatic fructolysis and improved glucose tolerance. Conversely, the KHK inhibitor only partially reduced fructolysis, but it also targeted triokinase, mediating the third step of fructolysis. This led to the accumulation of fructose-1 phosphate, resulting in glycogen accumulation, hepatomegaly, and impaired glucose tolerance. Overexpression of wild-type, but not kinase-dead, KHK in cultured hepatocytes increased hepatocyte injury and glycogen accumulation after treatment with fructose. The differences between KHK inhibition and knockdown are, in part, explained by the kinase-dependent and -independent effects of KHK on hepatic metabolism.

Higher levels of plasmatic saturated fatty acid were significantly associated with liver fibrosis in HIV mono-infection: A case-control study

Background

The relationship between plasmatic fatty acid (FA) composition and liver fibrosis remains scarce in people living with HIV/AIDS (PLWHA). We aimed to evaluate the association of plasmatic FAs and liver fibrosis in HIV mono-infected individuals.

Methods

This case-control study included PLWHA with liver fibrosis (cases) and randomly selected subjects without fibrosis (controls) from the PROSPEC-HIV study (NCT02542020). Participants with viral hepatitis, abusive alcohol consumption and lipid supplements use were excluded. Liver fibrosis was defined using transient elastography (TE) by liver stiffness measurement (LSM) ≥ 7.1 kPa or ≥ 6.2 kPa with M or XL probe, respectively. All HIV mono-infected participants with liver fibrosis identified at the baseline PROSPEC-HIV visit were included. Controls (1:1) were randomly selected among those HIV mono-infected participants without liver fibrosis. Plasmatic FA profile, dietary lipid intake, anthropometric measures, and blood samples were assessed. Plasmatic fatty acid was analyzed using gas chromatography and intake of fats lipids were assessed by two 24-h dietary recall (24-HDR). Multivariate logistic regression models adjusted by age, sex at birth and duration of antiretroviral therapy (ART) were performed.

Results

A total of 142 participants (71 cases and 71 controls) [62 % female, median age = 46 (IQR, 37-53) years, 14.8 % with diabetes, median CD4 count = 655 cells/mm3, 96.5 % under ART] were included. Higher percentages of plasmatic palmitc acid (16:0) and saturated fatty acids (SFA) were observed in participants with liver fibrosis (cases) compared to those without (controls). Presence of higher percentage of plasmatic palmitc acid (16:0) was associated with an increased odds for liver fibrosis [adjusted OR = 1.23 (95%CI 1.04-1.46); p = 0.02] in multivariate models.

Conclusion

This study showed the potential role of the plasmatic FA composition in the pathogenesis of liver fibrosis in PLWHA.

Therapeutic landscape of metabolic dysfunction-associated steatohepatitis (MASH)

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its severe subgroup metabolic dysfunction-associated steatohepatitis (MASH) have become a global epidemic and are driven by chronic overnutrition and multiple genetic susceptibility factors. The physiological outcomes include hepatocyte death, liver inflammation and cirrhosis. The first therapeutic for MASLD and MASH, resmetirom, has recently been approved for clinical use and has energized this therapeutic space. However, there is still much to learn in clinical studies of MASH, such as the scale of placebo responses, optimal trial end points, the time required for fibrosis reversal and side effect profiles. This Review introduces aspects of disease pathogenesis related to drug development and discusses two main therapeutic approaches. Thyroid hormone receptor-β agonists, such as resmetirom, as well as fatty acid synthase inhibitors, target the liver and enable it to function within a toxic metabolic environment. In parallel, incretin analogues such as semaglutide improve metabolism, allowing the liver to self-regulate and reversing many aspects of MASH. We also discuss how combinations of therapeutics could potentially be used to treat patients.

The propensity of fructose to induce metabolic dysfunction is dependent on the baseline diet, length of the dietary exposure, and sex of the mice

Background/Objectives

Numerous studies have implicated high intake of sugar, particularly fructose, with the development of obesity and metabolic complications. On the other hand, fructose from fruits and vegetables has undisputed benefits for metabolic health. This paradox questions how the same fructose molecule can be associated with detrimental health effects in some studies and beneficial in others.

Methods

To answer this question, male and female mice were fed different normal chow diets and provided 30% fructose solution in water.

Results

Fructose-supplemented male mice on the Boston Chow Diet (BCD=23% protein, 22% fat, 55% carbs) gained weight, developed glucose intolerance and hepatic steatosis. In contrast, male mice on the Lexington Chow Diet (LXD=24% protein, 18% fat, 58% carbs) did not gain weight, remained glucose tolerant, and had normal hepatic lipid content when supplemented with fructose. Furthermore, fructose-fed male mice on a Low-Fat Diet (LFD=20% protein, 10% fat, 70% carbs) didn't gain weight, but once switched to the BCD, they gained weight, exhibited worsening liver steatosis, and more advanced hepatic insulin resistance. The effects of fructose are sex-dependent, as female mice didn't gain weight and remained insulin-sensitive when given fructose on BCD, despite developing hepatic steatosis.

Conclusions

The differences in metabolic outcomes correlate with the propensity of the baseline diet to suppress hepatic ketohexokinase expression and the de novo lipogenesis pathway. This is likely driven by the dietary fat-to-carbohydrate ratio. Thus, metabolic dysfunction attributed to fructose intake is not a universal outcome; rather, it depends on the baseline diet, sex, and exposure length.

Amelioration of fructose-induced hepatic lipid accumulation by vitamin D3 supplementation and high-intensity interval training in male Sprague‒Dawley rats

BACKGROUND

Intrahepatic lipid accumulation (IHL), a hallmark of metabolic disorders, is closely associated with de novo lipogenesis (DNL). Notably, fructose feeding increased the DNL. Lifestyle modifications resulting from dietary changes and increased physical activity/exercise can decrease the IHL content. We examined the effects of vitamin D3 supplementation (VDS), high-intensity interval training (HIIT), and their combination on the transcription factors and enzymes of the DNL pathway in male Sprague‒Dawley rats fed a high-fructose diet (HFrD).

METHODS

Forty male rats were assigned to 5 groups (n = 8): CS (the control group had a standard diet); CF (the control group had HFrD (10% (w/v) fructose solution in tap water)); and FT (HFrD + HIIT: 10 bouts of 4 min of high-intensity running, corresponding to 85-90% of the maximal speed with 2 min active rest periods of 50% maximal speed, 5 days per week); FD (HFrD + intervention of intraperitoneal injection of 10000 IU/kg/week VDS); FTD (HFrD + HIIT + VDS) that were maintained for 12 weeks. ELISA, the GOD-POD assay, folch, western blotting, and oil red O staining were used to determine insulin, fasting blood glucose (FBG), hepatic triglyceride (TG) and cholesterol levels; SREBP1c, ChREBP-β, ACC1, FASN, p-ACC1, AMPK, p-AMPK, and PKA protein expression; and IHL content, respectively.

RESULTS

Both HIIT and VDS led to significant increases in the levels of PKA, AMPK, p-AMPK, and p-ACC1, as well as significant decreases in the levels of SREBP1c, ChREBP-β, ACC1, FASN, insulin, FBG, liver TG, liver cholesterol, and IHL. HIIT exhibited superior efficacy over VDS in reducing ChREBP-β, ACC1, insulin, FBG, liver TG and cholesterol, as well as increasing p-ACC1 and PKA. Notably, the combined intervention of HIIT and VDS yielded the most substantial improvements across all the parameters.

CONCLUSIONS

HFrD causes IHL accumulation and the onset of diabetes, whereas VDS and HIIT, along with their combined effects, prevent the consequences of HFrD.

Transcriptional Regulation of De Novo Lipogenesis by SIX1 in Liver Cancer Cells

De novo lipogenesis (DNL), a hallmark of cancer, facilitates tumor growth and metastasis. Therapeutic drugs targeting DNL are being developed. However, how DNL is directly regulated in cancer remains largely unknown. Here, transcription factor sine oculis homeobox 1 (SIX1) is shown to directly increase the expression of DNL-related genes, including ATP citrate lyase (ACLY), fatty acid synthase (FASN), and stearoyl-CoA desaturase 1 (SCD1), via histone acetyltransferases amplified in breast cancer 1 (AIB1) and lysine acetyltransferase 7 （HBO1/KAT7）, thus promoting lipogenesis. SIX1 expression is regulated by insulin/lncRNA DGUOK-AS1/microRNA-145-5p axis, which also modulates DNL-related gene expression as well as DNL. The DGUOK-AS1/microRNA-145-5p/SIX1 axis regulates liver cancer cell proliferation, invasion, and metastasis in vitro and in vivo. In patients with liver cancer, SIX1 expression is positively correlated with DGUOK-AS1 and SCD1 expression and is negatively correlated with microRNA-145-5p expression. DGUOK-AS1 is a good predictor of prognosis. Thus, the DGUOK-AS1/microRNA-145-5p/SIX1 axis strongly links DNL to tumor growth and metastasis and may become an avenue for liver cancer therapeutic intervention.

Hepatocyte-Specific Casein Kinase 1 Epsilon Ablation Ameliorates Metabolic Dysfunction-Associated Steatohepatitis by Up-Regulating Tumor Necrosis Factor Receptor-Associated Factor 3 in Mice

Casein kinase 1 epsilon (CK1ε), a member of the serine/threonine protein kinase family, phosphorylates a broad range of substrates. However, its role in the development of chronic liver diseases remains elusive. This study aimed to investigate the role of CK1ε in the development and progression of metabolic dysfunction-associated steatohepatitis (MASH). Hepatocyte-specific CK1ε knockout (CK1εΔHEP) mice were generated by crossbreeding mice with floxed CK1ε alleles (CK1εfl/fl) and Cre-expressing albumin mice. Mice were fed either a Western diet (WD) or a methionine- and choline-deficient diet to induce MASH. CK1εΔHEP was associated with a decreased severity of WD- or methionine- and choline-deficient diet-induced MASH, as confirmed by reduced incidence of hepatic lesions and significantly lower levels of alanine aminotransferase, aspartate aminotransferase, and proinflammatory cytokine tumor necrosis factor (TNF)-α. CK1εΔHEP WD-fed mice exhibited significant amelioration of total cholesterol, triglycerides, and de novo lipogenic genes, indicating that CK1ε could influence lipid metabolism. CK1εΔHEP WD-fed mice showed significantly down-regulated TNF receptor-associated factor (TRAF) 3, phosphorylated (p) transforming growth factor-β-activated kinase 1, p-TRAF-associated NF-κB activator (TANK)-binding kinase 1 (TBK1), and p-AKT levels, thereby affecting downstream mitogen-activated protein kinase signaling, indicating a potential mechanism for the observed rescue. Finally, pharmacologic inhibition of CK1ε with PF670462 improved palmitic acid-induced steatohepatitis in vitro and attenuated WD-induced metabolic profile in vivo. In conclusion, CK1ε up-regulates TNF receptor-associated factor 3, which, in turn, causes transforming growth factor-β-activated kinase 1-dependent signaling, amplifies downstream mitogen-activated protein kinase signaling, modifies p-c-Jun levels, and exacerbates inflammation, all of which are factors in WD-induced metabolic dysfunction-associated steatotic liver disease.

Dietary Fructose: A Literature Review of Current Evidence and Implications on Metabolic Health

With the increasing intake of dietary fructose, primarily from sucrose and sweetened beverages, metabolic illnesses such as type 2 diabetes mellitus, hypertension, fatty liver disease, dyslipidemia, and hyperuricemia have become more prevalent worldwide, and there is also growing concern about the development of malignancies. These negative health impacts have been validated in various meta-analyses and randomized controlled trials. In contrast, the naturally occurring fructose found in fruits and vegetables contains only a minimal amount of fructose and, when consumed in moderation, may be a healthier choice. This review focuses on the biology of fructose, including its dietary sources, the physiology of its metabolism, and the pathological basis of various disorders related to high dietary fructose intake.

Identification of diagnostic markers pyrodeath-related genes in non-alcoholic fatty liver disease based on machine learning and experiment validation

Non-alcoholic fatty liver disease (NAFLD) poses a global health challenge. While pyroptosis is implicated in various diseases, its specific involvement in NAFLD remains unclear. Thus, our study aims to elucidate the role and mechanisms of pyroptosis in NAFLD. Utilizing data from the Gene Expression Omnibus (GEO) database, we analyzed the expression levels of pyroptosis-related genes (PRGs) in NAFLD and normal tissues using the R data package. We investigated protein interactions, correlations, and functional enrichment of these genes. Key genes were identified employing multiple machine learning techniques. Immunoinfiltration analyses were conducted to discern differences in immune cell populations between NAFLD patients and controls. Key gene expression was validated using a cell model. Analysis of GEO datasets, comprising 206 NAFLD samples and 10 controls, revealed two key PRGs (TIRAP, and GSDMD). Combining these genes yielded an area under the curve (AUC) of 0.996 for diagnosing NAFLD. In an external dataset, the AUC for the two key genes was 0.825. Nomogram, decision curve, and calibration curve analyses further validated their diagnostic efficacy. These genes were implicated in multiple pathways associated with NAFLD progression. Immunoinfiltration analysis showed significantly lower numbers of various immune cell types in NAFLD patient samples compared to controls. Single sample gene set enrichment analysis (ssGSEA) was employed to assess the immune microenvironment. Finally, the expression of the two key genes was validated in cell NAFLD model using qRT-PCR. We developed a prognostic model for NAFLD based on two PRGs, demonstrating robust predictive efficacy. Our findings enhance the understanding of pyroptosis in NAFLD and suggest potential avenues for therapeutic exploration.

6-Gingerol Inhibits De Novo Lipogenesis by Targeting Stearoyl-CoA Desaturase to Alleviate Fructose-Induced Hepatic Steatosis

Metabolic-associated fatty liver disease (MAFLD), also known as non-alcoholic fatty liver disease (NAFLD), is a worldwide liver disease without definitive or widely used therapeutic drugs in clinical practice. In this study, we confirm that 6-gingerol (6-G), an active ingredient of ginger (Zingiber officinale Roscoe) in traditional Chinese medicine (TCM), can alleviate fructose-induced hepatic steatosis. It was found that 6-G significantly decreased hyperlipidemia caused by high-fructose diets (HFD) in rats, and reversed the increase in hepatic de novo lipogenesis (DNL) and triglyceride (TG) levels induced by HFD, both in vivo and in vitro. Mechanistically, chemical proteomics and cellular thermal shift assay (CETSA)-proteomics approaches revealed that stearoyl-CoA desaturase (SCD) is a direct binding target of 6-G, which was confirmed by further CETSA assay and molecular docking. Meanwhile, it was found that 6-G could not alter SCD expression (in either mRNA or protein levels), but inhibited SCD activity (decreasing the desaturation levels of fatty acids) in HFD-fed rats. Furthermore, SCD deficiency mimicked the ability of 6-G to reduce lipid accumulation in HF-induced HepG2 cells, and impaired the improvement in hepatic steatosis brought about by 6-G treatment in HFD supplemented with oleic acid diet-induced SCD1 knockout mice. Taken together, our present study demonstrated that 6-G inhibits DNL by targeting SCD to alleviate fructose diet-induced hepatic steatosis.

Lactiplantibacillus plantarum P101 Alleviated Alcohol-Induced Hepatic Lipid Accumulation in Mice via AMPK Signaling Pathway: Gut Microbiota and Metabolomics Analysis

Mitigating steatosis is essential for delaying the progression of alcoholic liver disease. The effect and mechanism of Lactiplantibacillus plantarum P101 (LP.P101) on alleviating alcohol-induced hepatic lipid accumulation were investigated in our study. The mouse model was constructed by a short-term (10-day)-plus-binge ethanol feeding and gavaged with 108 CFU/mL of LP.P101 daily. Lipid droplet in the liver was significantly reduced by LP.101 intervention on AMPK activation. However, when AMPK was inhibited by dorsomorphin, the levels of related indicators (ALT, TG, etc.) and the expression levels of AMPK and relevant genes in the liver converged to that of the alcohol-fed group. Compared with the alcohol-fed group, LP.P101 reduced the relative abundance of Firmicutes and increased that of Bacteroidetes. Parabacteroides merdae was negatively correlated with lipid accumulation, and unclassified Negativibacillus was negatively associated with AMPK activation. Importantly, LP.P101 modified the compositions of the serum metabolites. The potential biomarker stercobilinogen was positively correlated with AMPK activation and negatively associated with lipid accumulation. This work confirmed that LP.P101 attenuated alcohol-induced hepatic lipid accumulation in mice through AMPK activation, and the alterations in gut microbiota and metabolites may play a significant role on AMPK activation.

Chinese herbal formula in the treatment of metabolic dysfunction-associated steatotic liver disease: current evidence and practice

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease, continues to rise with rapid economic development and poses significant challenges to human health. No effective drugs are clinically approved. MASLD is regarded as a multifaceted pathological process encompassing aberrant lipid metabolism, insulin resistance, inflammation, gut microbiota imbalance, apoptosis, fibrosis, and cirrhosis. In recent decades, herbal medicines have gained increasing attention as potential therapeutic agents for the prevention and treatment of MASLD, due to their good tolerance, high efficacy, and low toxicity. In this review, we summarize the pathological mechanisms of MASLD; emphasis is placed on the anti-MASLD mechanisms of Chinese herbal formula (CHF), especially their effects on improving lipid metabolism, inflammation, intestinal flora, and fibrosis. Our goal is to better understand the pharmacological mechanisms of CHF to inform research on the development of new drugs for the treatment of MASLD.

Inhibition of hepatic oxalate overproduction ameliorates metabolic dysfunction-associated steatohepatitis

The incidence of metabolic dysfunction-associated steatohepatitis (MASH) is on the rise, and with limited pharmacological therapy available, identification of new metabolic targets is urgently needed. Oxalate is a terminal metabolite produced from glyoxylate by hepatic lactate dehydrogenase (LDHA). The liver-specific alanine-glyoxylate aminotransferase (AGXT) detoxifies glyoxylate, preventing oxalate accumulation. Here we show that AGXT is suppressed and LDHA is activated in livers from patients and mice with MASH, leading to oxalate overproduction. In turn, oxalate promotes steatosis in hepatocytes by inhibiting peroxisome proliferator-activated receptor-α (PPARα) transcription and fatty acid β-oxidation and induces monocyte chemotaxis via C-C motif chemokine ligand 2. In male mice with diet-induced MASH, targeting oxalate overproduction through hepatocyte-specific AGXT overexpression or pharmacological inhibition of LDHA potently lowers steatohepatitis and fibrosis by inducing PPARα-driven fatty acid β-oxidation and suppressing monocyte chemotaxis, nuclear factor-κB and transforming growth factor-β targets. These findings highlight hepatic oxalate overproduction as a target for the treatment of MASH.

Effects of semaglutide-loaded lipid nanocapsules on metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a highly prevalent chronic liver disease that can progress to end-stage conditions with life-threatening complications, but no pharmacologic therapy has been approved. Drug delivery systems such as lipid nanocapsules (LNC) are very versatile platforms that are easy to produce and can induce the secretion of the native glucagon-like peptide 1 (GLP-1) when orally administered. GLP-1 analogs are currently being studied in clinical trials in the context of MASLD. Our nanosystem provides with increased levels of the native GLP-1 and increased plasmatic absorption of the encapsulated GLP-1 analog (semaglutide). Our goal was to use our strategy to demonstrate a better outcome and a greater impact on the metabolic syndrome associated with MASLD and on liver disease progression with our strategy compared with the oral marketed version of semaglutide, Rybelsus®. Therefore, we studied the effect of our nanocarriers on a dietary mouse model of MASLD, the Western diet model, during a daily chronic treatment of 4 weeks. Overall, the results showed a positive impact of semaglutide-loaded lipid nanocapsules towards the normalization of glucose homeostasis and insulin resistance. In the liver, there were no significant changes in lipid accumulation, but an improvement in markers related to inflammation was observed. Overall, our strategy had a positive trend on the metabolic syndrome and at reducing inflammation, mitigating the progression of the disease. Oral administration of the nanosystem was more efficient at preventing the progression of the disease to more severe states when compared to the administration of Rybelsus®, as a suspension.

Obesity, Metabolic Syndrome, and Sugar-Sweetened Beverages (SSBs) in America: A Novel Bioethical Argument for a Radical Public Health Proposal

The prevalence of obesity, metabolic syndrome, and the associated long-term chronic diseases (cardiovascular disease, type II diabetes, cancer, Alzheimer's disease, depression) have reached epidemic levels in the United States and Western nations. In response to this public health calamity, the author of this paper presents and defends a novel bioethical argument: the consistency argument for outlawing SSBs (sugar-sweetened beverages) for child consumption (the "consistency argument"). This argument's radical conclusion states that the government is justified in outlawing SSBs consumption for child consumption. The reasoning is as follows: if one accepts that the physical harm caused by chronic alcohol consumption justifies the government outlawing alcoholic beverages for child consumption, and there is strong evidence that comparable physical harms result from chronic SSBs consumption, then, mutatis mutandis, the government is also justified in outlawing child consumption of SSBs. To support this argument, the author provides extensive evidence based on epidemiological observational studies, interventional studies, controlled trials, large meta-analyses, and the pathophysiology and biological mechanisms of action behind SSBs and chronic disease. Chronic consumption of large doses of SSBs and alcoholic beverages both drive the same diseases: obesity and insulin resistance, cardiovascular disease, hypertension, and cancer. Chronic SSB consumption carries the additional risk of Alzheimer's disease, dementia, and depression. The author concludes this paper by considering prominent objections to the consistency argument, and then demonstrating that each objection is unsound.

Lipoprotein Lipidomics as a Frontier in Non-Alcoholic Fatty Liver Disease Biomarker Discovery

Non-alcoholic fatty liver disease (NAFLD) is a progressive liver disease characterized by the build-up of fat in the liver of individuals in the absence of alcohol consumption. This condition has become a burden in modern societies aggravated by the lack of appropriate predictive biomarkers (other than liver biopsy). To better understand this disease and to find appropriate biomarkers, a new technology has emerged in the last two decades with the ability to explore the unmapped role of lipids in this disease: lipidomics. This technology, based on the combination of chromatography and mass spectrometry, has been extensively used to explore the lipid metabolism of NAFLD. In this review, we aim to summarize the knowledge gained through lipidomics assays exploring tissues, plasma, and lipoproteins from individuals with NAFLD. Our goal is to identify common features and active pathways that could facilitate the finding of a reliable biomarker from this field. The most frequent observation was a variable decrease (1-9%) in polyunsaturated fatty acids in phospholipids and non-esterified fatty acids in NAFLD patients, both in plasma and liver. Additionally, a reduction in phosphatidylcholines is a common feature in the liver. Due to the scarcity of studies, further research is needed to properly detect lipoprotein, plasma, and tissue lipid signatures of NAFLD etiologies, and NAFLD subtypes, and to define the relevance of this technology in disease management strategies in the push toward personalized medicine.

Hepatocyte programmed cell death: the trigger for inflammation and fibrosis in metabolic dysfunction-associated steatohepatitis

By replacing and removing defective or infected cells, programmed cell death (PCD) contributes to homeostasis maintenance and body development, which is ubiquitously present in mammals and can occur at any time. Besides apoptosis, more novel modalities of PCD have been described recently, such as necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death. PCD not only regulates multiple physiological processes, but also participates in the pathogenesis of diverse disorders, including metabolic dysfunction-associated steatotic liver disease (MASLD). MASLD is mainly classified into metabolic dysfunction-associated steatotic liver (MASL) and metabolic dysfunction-associated steatohepatitis (MASH), and the latter putatively progresses to cirrhosis and hepatocellular carcinoma. Owing to increased incidence and obscure etiology of MASH, its management still remains a tremendous challenge. Recently, hepatocyte PCD has been attracted much attention as a potent driver of the pathological progression from MASL to MASH, and some pharmacological agents have been proved to exert their salutary effects on MASH partly via the regulation of the activity of hepatocyte PCD. The current review recapitulates the pathogenesis of different modalities of PCD, clarifies the mechanisms underlying how metabolic disorders in MASLD induce hepatocyte PCD and how hepatocyte PCD contributes to inflammatory and fibrotic progression of MASH, discusses several signaling pathways in hepatocytes governing the execution of PCD, and summarizes some potential pharmacological agents for MASH treatment which exert their therapeutic effects partly via the regulation of hepatocyte PCD. These findings indicate that hepatocyte PCD putatively represents a new therapeutic point of intervention for MASH.

Activation of AMPD2 drives metabolic dysregulation and liver disease in mice with hereditary fructose intolerance

Hereditary fructose intolerance (HFI) is a painful and potentially lethal genetic disease caused by a mutation in aldolase B resulting in accumulation of fructose-1-phosphate (F1P). No cure exists for HFI and treatment is limited to avoid exposure to fructose and sugar. Using aldolase B deficient mice, here we identify a yet unrecognized metabolic event activated in HFI and associated with the progression of the disease. Besides the accumulation of F1P, here we show that the activation of the purine degradation pathway is a common feature in aldolase B deficient mice exposed to fructose. The purine degradation pathway is a metabolic route initiated by adenosine monophosphate deaminase 2 (AMPD2) that regulates overall energy balance. We demonstrate that very low amounts of fructose are sufficient to activate AMPD2 in these mice via a phosphate trap. While blocking AMPD2 do not impact F1P accumulation and the risk of hypoglycemia, its deletion in hepatocytes markedly improves the metabolic dysregulation induced by fructose and corrects fat and glycogen storage while significantly increasing the voluntary tolerance of these mice to fructose. In summary, we provide evidence for a critical pathway activated in HFI that could be targeted to improve the metabolic consequences associated with fructose consumption.

The Effects of Long-Term High Fat and/or High Sugar Feeding on Sources of Postprandial Hepatic Glycogen and Triglyceride Synthesis in Mice

BACKGROUND

In MASLD (formerly called NAFLD) mouse models, oversupply of dietary fat and sugar is more lipogenic than either nutrient alone. Fatty acids suppress de novo lipogenesis (DNL) from sugars, while DNL inhibits fatty acid oxidation. How such factors interact to impact hepatic triglyceride levels are incompletely understood.

METHODS

Using deuterated water, we measured DNL in mice fed 18-weeks with standard chow (SC), SC supplemented with 55/45-fructose/glucose in the drinking water at 30% (w/v) (HS), high-fat chow (HF), and HF with HS supplementation (HFHS). Liver glycogen levels and its sources were also measured. For HS and HFHS mice, pentose phosphate (PP) fluxes and fructose contributions to DNL and glycogen were measured using [U-13C]fructose.

RESULTS

The lipogenic diets caused significantly higher liver triglyceride levels compared to SC. DNL rates were suppressed in HF compared to SC and were partially restored in HFHS but supplied a minority of the additional triglyceride in HFHS compared to HF. Fructose contributed a significantly greater fraction of newly synthesized saturated fatty acids compared to oleic acid in both HS and HFHS. Glycogen levels were not different between diets, but significant differences in Direct and Indirect pathway contributions to glycogen synthesis were found. PP fluxes were similar in HS and HFHS mice and were insufficient to account for DNL reducing equivalents.

CONCLUSIONS

Despite amplifying the lipogenic effects of fat, the fact that sugar-activated DNL per se barely contributes suggests that its role is likely more relevant in the inhibition of fatty acid oxidation. Fructose promotes lipogenesis of saturated over unsaturated fatty acids and contributes to maintenance of glycogen levels. PP fluxes associated with sugar conversion to fat account for a minor fraction of DNL reducing equivalents.

Recent Advances on Sex Hormone-Binding Globulin Regulation by Nutritional Factors: Clinical Implications

Sex hormone-binding globulin (SHBG) is a homodimeric glycoprotein produced by the human liver and secreted into the systemic circulation where it binds with high affinity sex steroids regulating their availability in blood and accessibility to target tissues. Plasma SHBG levels are altered in metabolic disorders such as obesity, anorexia, and insulin resistance. Several reports have shown that diets in terms of total calories or fat, fiber, or protein content can alter plasma SHBG levels. However, there are many components in a diet that can affect SHBG gene expression in the liver. In order to unravel the molecular mechanisms by which diets regulate SHBG production, it would be necessary to analyze single diet components and/or nutritional factors. This review summarizes the recent advances in identifying different nutritional factors regulating SHBG production and the related molecular mechanism, as well as the clinical implications.

Hepatic glucagon action: beyond glucose mobilization

Glucagon's ability to promote hepatic glucose production has been known for over a century, with initial observations touting this hormone as a diabetogenic agent. However, glucagon receptor agonism [when balanced with an incretin, including glucagon-like peptide 1 (GLP-1) to dampen glucose excursions] is now being developed as a promising therapeutic target in the treatment of metabolic diseases, like metabolic dysfunction-associated steatotic disease/metabolic dysfunction-associated steatohepatitis (MASLD/MASH), and may also have benefit for obesity and chronic kidney disease. Conventionally regarded as the opposing tag-team partner of the anabolic mediator insulin, glucagon is gradually emerging as more than just a "catabolic hormone." Glucagon action on glucose homeostasis within the liver has been well characterized. However, growing evidence, in part thanks to new and sensitive "omics" technologies, has implicated glucagon as more than just a "glucose liberator." Elucidation of glucagon's capacity to increase fatty acid oxidation while attenuating endogenous lipid synthesis speaks to the dichotomous nature of the hormone. Furthermore, glucagon action is not limited to just glucose homeostasis and lipid metabolism, as traditionally reported. Glucagon plays key regulatory roles in hepatic amino acid and ketone body metabolism, as well as mitochondrial turnover and function, indicating broader glucagon signaling consequences for metabolic homeostasis mediated by the liver. Here we examine the broadening role of glucagon signaling within the hepatocyte and question the current dogma, to appreciate glucagon as more than just that "catabolic hormone."

Suppression of hepatic ChREBP⍺-CYP2C50 axis-driven fatty acid oxidation sensitizes mice to diet-induced MASLD/MASH

OBJECTIVES

Compromised hepatic fatty acid oxidation (FAO) has been observed in human MASH patients and animal models of MASLD/MASH. It remains poorly understood how and when the hepatic FAO pathway is suppressed during the progression of MASLD towards MASH. Hepatic ChREBP⍺ is a classical lipogenic transcription factor that responds to the intake of dietary sugars.

METHODS

We examined its role in regulating hepatocyte fatty acid oxidation (FAO) and the impact of hepatic Chrebpa deficiency on sensitivity to diet-induced MASLD/MASH in mice.

RESULTS

We discovered that hepatocyte ChREBP⍺ is both necessary and sufficient to maintain FAO in a cell-autonomous manner independently of its DNA-binding activity. Supplementation of synthetic PPAR⍺/δ agonist is sufficient to restore FAO in Chrebp-/- primary mouse hepatocytes. Hepatic ChREBP⍺ was decreased in mouse models of diet-induced MAFSLD/MASH and in patients with MASH. Hepatocyte-specific Chrebp⍺ knockout impaired FAO, aggravated liver steatosis and inflammation, leading to early-onset fibrosis in response to diet-induced MASH. Conversely, liver overexpression of ChREBP⍺-WT or its non-lipogenic mutant enhanced FAO, reduced lipid deposition, and alleviated liver injury, inflammation, and fibrosis. RNA-seq analysis identified the CYP450 epoxygenase (CYP2C50) pathway of arachidonic acid metabolism as a novel target of ChREBP⍺. Over-expression of CYP2C50 partially restores hepatic FAO in primary hepatocytes with Chrebp⍺ deficiency and attenuates preexisting MASH in the livers of hepatocyte-specific Chrebp⍺-deleted mice.

CONCLUSIONS

Our findings support the protective role of hepatocyte ChREBPa against diet-induced MASLD/MASH in mouse models in part via promoting CYP2C50-driven FAO.

Androsin alleviates non-alcoholic fatty liver disease by activating autophagy and attenuating de novo lipogenesis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease with therapeutic options on the horizon. Picrorhiza kurroa, enriched with iridoid glycosides like picroside I and picroside II is known for its hepatoprotective activity and anti-inflammatory properties. Androsin, the other phytochemical present in P. kurroa has been shown to have anti-inflammatory and anti-asthmatic properties. However, its role in NAFLD is yet to be investigated.

PURPOSE

This study aims to identify the potent hepatoprotective agent from P. kurroa that can attenuate NAFLD in HFrD-fed ApoE-/- mice, and elucidate the underlying mechanisms governing its effects.

METHODS

Classical purification methods were used to isolate seven compounds, including picroside I, picroside II and androsin from the roots of P. kurroa. NAFLD-induced ApoE-/- mice were administered orally with either picroside I, picroside II, or androsin for 7 weeks. Animals were scanned non-invasively by ultrasonography at 1st and 14th week. Gross histomorphometry was examined by HE and Sirius red staining. mRNA transcript and protein profile associated with autophagy, lipogenesis, inflammation, and fibrosis was done through RT-PCR and Western blot analysis.

RESULTS

In-vitro and in-vivo studies revealed that among the seven evaluated compounds, androsin shows the most potent in-vitro activity. Oral dosing of androsin (10 mg/kg) protected the liver against HFrD-induced NAFLD in ApoE-/- mice model. Biochemical analysis revealed a reduction in ALT and AST enzymes and a significant reduction in cholesterol levels. Hepatocyte ballooning, hepatic lipid deposition, inflammation, and fibrosis were reduced. Androsin treatment significantly reduced fibrosis (α-SMA, collagens, TGF-β) and inflammation (ILs, TNF-α, NFκB) in ApoE-/- mice. Mechanistically, androsin activated AMPKα and down-regulated the expression of SREBP-1c, resulting in ameliorating hepatic lipogenesis.

CONCLUSION

Our results support autophagy as one of the therapeutic strategies to reduce steatosis and hepatic damage. We found that androsin treatment significantly ameliorated hepatic steatosis, serum lipid levels, and hepatic injury in ApoE-/- induced by HFrD. Androsin administration mitigated lipogenesis by inhibiting SREBP1c/FASN pathway and activating autophagy through AMPKα/PI3K/Beclin1/LC3 pathway.