Dysregulation of Lipid and Glucose Metabolism in Nonalcoholic Fatty Liver Disease

Immunology and treatments of fatty liver disease

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are two major chronic liver diseases worldwide. The triggers for fatty liver can be derived from external sources such as adipose tissue, the gut, personal diet, and genetics, or internal sources, including immune cell responses, lipotoxicity, hepatocyte death, mitochondrial dysfunction, and extracellular vesicles. However, their pathogenesis varies to some extent. This review summarizes various immune mechanisms and therapeutic targets associated with these two types of fatty liver disease. It describes the gut-liver axis and adipose tissue-liver crosstalk, as well as the roles of different immune cells (both innate and adaptive immune cells) in fatty liver disease. Additionally, mitochondrial dysfunction, extracellular vesicles, microRNAs (miRNAs), and gastrointestinal hormones are also related to the pathogenesis of fatty liver. Understanding the pathogenesis of fatty liver and corresponding therapeutic strategies provides a new perspective for developing novel treatments for fatty liver disease.

Unraveling the cGAS/STING signaling mechanism: impact on glycerolipid metabolism and diseases

The cyclic GMP-AMP synthase (cGAS) and its downstream effector, the stimulator of interferon genes (STING), are crucial components of the innate immune response, traditionally recognized for their role in detecting cytosolic DNA from pathogens and damaged host cells. However, recent research indicates that the cGAS-STING pathway also significantly impacts metabolic processes, particularly glycerolipid metabolism. Glycerolipids are essential for energy storage and cellular membrane integrity, and their dysregulation is linked to metabolic disorders such as obesity, insulin resistance, and non-alcoholic fatty liver disease (NAFLD). Both cGAS and STING are expressed in various metabolic tissues, suggesting a potential role in lipid homeostasis. Chronic activation of the cGAS-STING pathway may promote inflammatory states that exacerbate insulin resistance and lipid accumulation, forming a feedback loop of metabolic dysfunction. This review explores the emerging relationship between cGAS/STING signaling and glycerolipid metabolism, discussing the mechanisms through which this pathway influences lipid regulation and the potential for therapeutic interventions. By integrating insights from immunology and metabolism, we aim to provide a comprehensive understanding of how the cGAS-STING axis may serve as a novel target for addressing metabolic disorders and enhancing metabolic health outcomes.

Relationship between breastfeeding and hepatic steatosis in women with previous gestational diabetes mellitus

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), characterized by excess liver fat, is common in women with a history of gestational diabetes mellitus (GDM). While breastfeeding improves postpartum lipid levels, its impact on NAFLD in these women is not well studied. We aimed to investigate the relationship between the duration and intensity of breastfeeding and the amount of liver fat and prevalence of NAFLD in women with previous GDM at approximately 1 year postpartum.

METHODS

This prospective cohort study was conducted at a university hospital in Bangkok, Thailand between November 2021 and February 2024. Overall, 130 women who had experienced GDM in their most recent pregnancy were followed up for 1 year postpartum. We collected data on breastfeeding practices and quantified liver fat using controlled attenuation parameters (CAPs) during transient elastography. NAFLD was defined as a CAP of ≥ 302 dB/m. Women were divided into three groups according to the duration and intensity of breastfeeding: group 1 (breastfeeding for < 6 months), group 2 (breastfeeding for ≥ 6 months and exclusive breastfeeding [EBF] for < 6 months), and group 3 (breastfeeding for ≥ 6 months and EBF for 6 months).

RESULTS

Overall, 57 (43.8%), 26 (20.0%), and 47 (36.2%) participants were categorized into groups 1, 2, and 3, respectively. Group 3 had the lowest CAPs, followed by groups 2 and 1. The median values (interquartile ranges) of the CAPs were 219.0 (189.0-271.0) dB/m, 257.5 (205.3-317.3) dB/m, and 279.0 (191.5-324.0) dB/m for groups 3, 2, and 1, respectively (p = 0.034). NAFLD prevalence was significantly lower in group 3 compared to groups 2 and 1 (19.1% vs. 38.5% vs. 43.9%, respectively; p = 0.026). Multivariate analysis showed that breastfeeding for ≥ 6 months and EBF for 6 months reduced the risk of NAFLD, with an adjusted odds ratio of 0.34 (95% confidence interval 0.14, 0.95).

CONCLUSIONS

Breastfeeding for ≥ 6 months, particularly EBF for the first 6 months, may offer a practical strategy to reduce the risk of NAFLD in women with prior GDM.

TRIAL REGISTRATION

Thai Clinical Trials Registry: Registration no. TCTR20211027008. Date of registration: October 27, 2021. Date of initial participant enrollment: November 1, 2021.

Unique and Shared Molecular Mechanisms of Alcoholic and Non-Alcoholic Liver Cirrhosis Identified Through Transcriptomics Data Integration

Liver cirrhosis is a severe chronic disease that results from various etiological factors and leads to substantial morbidity and mortality. Alcoholic cirrhosis (AC) and non-AC (NAC) arise from prolonged and excessive consumption of alcohol and metabolic syndromes, respectively. Precise molecular mechanisms of AC and NAC are yet to be comprehensively understood for diagnostics and therapeutic advances to materialize. This study reports novel findings to this end by utilizing high-throughput RNA sequencing and microarray data from the Gene Expression Omnibus (GEO). We performed a meta-analysis of transcriptomics data to identify the differentially expressed genes specific to AC and NAC. Functional enrichment and protein-protein interaction network analyses uncovered novel hub genes and transcription factors (TFs) critical to AC and NAC. We found that AC is primarily driven by metabolic dysregulation and oxidative stress, with key TFs such as RELA, NFKB1, and STAT3. NAC was characterized by fibrosis and tissue remodeling associated with metabolic dysfunction, with TFs including USF1, MYCN, and HIF1A. Key hub genes such as ESR1, JUN, FOS, and PKM in AC, and CD8A, MAPK3, CCND1, and CXCR4 in NAC were identified, along with their associated TFs, pointing to potential therapeutic targets. Our results underscore the unique and shared molecular mechanisms that underlie AC and NAC and inform the efforts toward precision medicine and improved patient outcomes in liver cirrhosis.

FOXO1 induced fatty acid oxidation in hepatic cells by targeting ALDH1L2

BACKGROUND AND AIM

Lipid metabolism disorder is the primary feature of numerous refractory chronic diseases. Fatty acid oxidation, an essential aerobic biological process, is closely related to the progression of NAFLD. The forkhead transcription factor FOXO1 has been reported to play an important role in lipid metabolism. However, the molecular mechanism through which FOXO1 regulates fatty acid oxidation remains unclear.

METHODS

Transcriptomic analysis was performed to examine the cellular expression profile to determine the functional role of FOXO1 in HepG2 cells with palmitic acid (PA)-induced lipid accumulation. FOXO1-binding motifs at the promoter region of aldehyde dehydrogenase 1 family member L2 (ALDH1L2) were predicted via bioinformatic analysis and confirmed via luciferase reporter assay. Overexpression of ALDH1L2 was induced to recover the impaired fatty acid oxidation in FOXO1-knockout cells.

RESULTS

Knockout of FOXO1 aggravated lipid deposition in hepatic cells. Transcriptomic profiling revealed that knockout of FOXO1 increased the expression of genes associated with fatty acid synthesis but decreased the expression of carnitine palmitoyltransferase1a (CPT1α) and adipose triglyceride lipase (ATGL), which contribute to fatty acid oxidation. Mechanistically, FOXO1 was identified as a transcription factor of ALDH1L2. Knockout of FOXO1 significantly decreased the protein expression of ALDH1L2 and CPT1α in vitro and in vivo. Furthermore, overexpression of ALDH1L2 restored fatty acid oxidation in FOXO1-knockout cells.

CONCLUSION

The findings of this study indicate that FOXO1 modulates fatty acid oxidation by targeting ALDH1L2.

Unveiling citicoline's mechanisms and clinical relevance in the treatment of neuroinflammatory disorders

Citicoline, a compound produced naturally in small amounts in the human body, assumes a pivotal role in phosphatidylcholine synthesis, a dynamic constituent of membranes of neurons. Across diverse models of brain injury and neurodegeneration, citicoline has demonstrated its potential through neuroprotective and anti-inflammatory effects. This review aims to elucidate citicoline's anti-inflammatory mechanism and its clinical implications in conditions such as ischemic stroke, head trauma, glaucoma, and age-associated memory impairment. Citicoline's anti-inflammatory prowess is rooted in its ability to stabilize cellular membranes, thereby curbing the excessive release of glutamate-a pro-inflammatory neurotransmitter. Moreover, it actively diminishes free radicals and inflammatory cytokines productions, which could otherwise harm neurons and incite neuroinflammation. It also exhibits the potential to modulate microglia activity, the brain's resident immune cells, and hinder the activation of NF-κB, a transcription factor governing inflammatory genes. Clinical trials have subjected citicoline to rigorous scrutiny in patients grappling with acute ischemic stroke, head trauma, glaucoma, and age-related memory impairment. While findings from these trials are mixed, numerous studies suggest that citicoline could confer improvements in neurological function, disability reduction, expedited recovery, and cognitive decline prevention within these cohorts. Additionally, citicoline boasts a favorable safety profile and high tolerability. In summary, citicoline stands as a promising agent, wielding both neuroprotective and anti-inflammatory potential across a spectrum of neurological conditions. However, further research is imperative to delineate the optimal dosage, treatment duration, and underlying mechanisms. Moreover, identifying specific patient subgroups most likely to reap the benefits of citicoline as a new therapy remains a critical avenue for exploration.

Converging Pathways between Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) and Diabetes in Children

In the past thirty years, childhood obesity rates have risen significantly worldwide, affecting over 340 million children in affluent nations. This surge is intricately tied to metabolic disorders, notably insulin resistance, type 2 diabetes mellitus (T2DM), and the continually evolving spectrum of metabolic-associated (dysfunction) steatotic liver disease (MASLD). This review underscores the alarming escalation of childhood obesity and delves comprehensively into the evolving and dynamic changes of nomenclature surrounding diverse conditions of hepatic steatosis, from the initial recognition of non-alcoholic fatty liver disease (NAFLD) to the progressive evolution into MASLD. Moreover, it emphasizes the crucial role of pediatric endocrinologists in thoroughly and accurately investigating MASLD onset in children with T2DM, where each condition influences and exacerbates the progression of the other. This review critically highlights the inadequacies of current screening strategies and diagnosis, stressing the need for a paradigm shift. A proposed solution involves the integration of hepatic magnetic resonance imaging assessment into the diagnostic arsenal for children showing insufficient glycemic control and weight loss post-T2DM diagnosis, thereby complementing conventional liver enzyme testing. This holistic approach aims to significantly enhance diagnostic precision, fostering improved outcomes in this vulnerable high-risk pediatric population.

Two-week continuous glucose monitoring-derived metrics and degree of hepatic steatosis: a cross-sectional study among Chinese middle-aged and elderly participants

BACKGROUND

Continuous glucose monitoring (CGM) devices provide detailed information on daily glucose control and glycemic variability. Yet limited population-based studies have explored the association between CGM metrics and fatty liver. We aimed to investigate the associations of CGM metrics with the degree of hepatic steatosis.

METHODS

This cross-sectional study included 1180 participants from the Guangzhou Nutrition and Health Study. CGM metrics, covering mean glucose level, glycemic variability, and in-range measures, were separately processed for all-day, nighttime, and daytime periods. Hepatic steatosis degree (healthy: n = 698; mild steatosis: n = 242; moderate/severe steatosis: n = 240) was determined by magnetic resonance imaging proton density fat fraction. Multivariate ordinal logistic regression models were conducted to estimate the associations between CGM metrics and steatosis degree. Machine learning models were employed to evaluate the predictive performance of CGM metrics for steatosis degree.

RESULTS

Mean blood glucose, coefficient of variation (CV) of glucose, mean amplitude of glucose excursions (MAGE), and mean of daily differences (MODD) were positively associated with steatosis degree, with corresponding odds ratios (ORs) and 95% confidence intervals (CIs) of 1.35 (1.17, 1.56), 1.21 (1.06, 1.39), 1.37 (1.19, 1.57), and 1.35 (1.17, 1.56) during all-day period. Notably, lower daytime time in range (TIR) and higher nighttime TIR were associated with higher steatosis degree, with ORs (95% CIs) of 0.83 (0.73, 0.95) and 1.16 (1.00, 1.33), respectively. For moderate/severe steatosis (vs. healthy) prediction, the average area under the receiver operating characteristic curves were higher for the nighttime (0.69) and daytime (0.66) metrics than that of all-day metrics (0.63, P < 0.001 for all comparisons). The model combining both nighttime and daytime metrics achieved the highest predictive capacity (0.73), with nighttime MODD emerging as the most important predictor.

CONCLUSIONS

Higher CGM-derived mean glucose and glycemic variability were linked with higher steatosis degree. CGM-derived metrics during nighttime and daytime provided distinct and complementary insights into hepatic steatosis.

The newly proposed plasma-glycosylated hemoglobin A1c/High-Density lipoprotein cholesterol ratio serves as a simple and practical indicator for screening metabolic associated fatty liver disease: an observational study based on a physical examination population

BACKGROUND

Glycotoxicity and lipotoxicity are key pathophysiological mechanisms underlying the development of metabolic associated fatty liver disease (MAFLD). The primary objective of this study is to investigate the association between the newly proposed Plasma-Glycosylated Hemoglobin A1c/High-Density Lipoprotein Cholesterol Ratio (HbA1c/HDL-C ratio) and the risk of MAFLD.

METHODS

A study population of 14,251 individuals undergoing health examinations was included. The association between the HbA1c/HDL-C ratio and MAFLD was analyzed using multivariable logistic regression and restricted cubic spline (RCS) analysis. Exploratory analyses were conducted to assess variations in this association across subgroups stratified by gender, age, body mass index (BMI), exercise habits, drinking status, and smoking status. The discriminatory value of the HbA1c/HDL-C ratio and its components for screening MAFLD was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

A total of 1,982 (13.91%) subjects were diagnosed with MAFLD. After adjusting for confounding factors, we found a significant positive association between the HbA1c/HDL-C ratio and MAFLD [odds ratio (OR) 1.34, 95% confidence interval (CI): 1.25, 1.44]. No significant differences in this association were observed across all subgroups (All P for interaction > 0.05). Furthermore, through RCS analysis, we observed a nonlinear positive correlation between the HbA1c/HDL-C ratio and MAFLD (P for non-linearity < 0.001), with a potential threshold effect point (approximately 3 for the HbA1c/HDL-C ratio). Beyond this threshold point, the slope of the MAFLD prevalence curve increased rapidly. Additionally, in further ROC analysis, we found that for the identification of MAFLD, the HbA1c/HDL-C ratio was significantly superior to HbA1c and HDL-C, with an area under the curve (AUC) and optimal threshold of 0.81 and 4.08, respectively.

CONCLUSIONS

Our findings suggest that the newly proposed HbA1c/HDL-C ratio serves as a simple and practical indicator for assessing MAFLD, exhibiting well-discriminatory performance in screening for MAFLD.

Physiological network approach to prognosis in cirrhosis: A shifting paradigm

Decompensated liver disease is complicated by multi-organ failure and poor prognosis. The prognosis of patients with liver failure often dictates clinical management. Current prognostic models have focused on biomarkers considered as individual isolated units. Network physiology assesses the interactions among multiple physiological systems in health and disease irrespective of anatomical connectivity and defines the influence or dependence of one organ system on another. Indeed, recent applications of network mapping methods to patient data have shown improved prediction of response to therapy or prognosis in cirrhosis. Initially, different physical markers have been used to assess physiological coupling in cirrhosis including heart rate variability, heart rate turbulence, and skin temperature variability measures. Further, the parenclitic network analysis was recently applied showing that organ systems connectivity is impaired in patients with decompensated cirrhosis and can predict mortality in cirrhosis independent of current prognostic models while also providing valuable insights into the associated pathological pathways. Moreover, network mapping also predicts response to intravenous albumin in patients hospitalized with decompensated cirrhosis. Thus, this review highlights the importance of evaluating decompensated cirrhosis through the network physiologic prism. It emphasizes the limitations of current prognostic models and the values of network physiologic techniques in cirrhosis.

Independent Associations of Aortic Calcification with Cirrhosis and Liver Related Mortality in Veterans with Chronic Liver Disease

INTRODUCTION

Abdominal aortic calcifications (AAC) are incidentally found on medical imaging and useful cardiovascular burden approximations. The Morphomic Aortic Calcification Score (MAC) leverages automated deep learning methods to quantify and score AACs. While associations of AAC and non-alcoholic fatty liver disease (NAFLD) have been described, relationships of AAC with other liver diseases and clinical outcome are sparse. This study's purpose was to evaluate AAC and liver-related death in a cohort of Veterans with chronic liver disease (CLD).

METHODS

We utilized the VISN 10 CLD cohort, a regional cohort of Veterans with the three forms of CLD: NAFLD, hepatitis C (HCV), alcohol-associated (ETOH), seen between 2008 and 2014, with abdominal CT scans (n = 3604). Associations between MAC and cirrhosis development, liver decompensation, liver-related death, and overall death were evaluated with Cox proportional hazard models.

RESULTS

The full cohort demonstrated strong associations of MAC and cirrhosis after adjustment: HR 2.13 (95% CI 1.63, 2.78), decompensation HR 2.19 (95% CI 1.60, 3.02), liver-related death HR 2.13 (95% CI 1.46, 3.11), and overall death HR 1.47 (95% CI 1.27, 1.71). These associations seemed to be driven by the non-NAFLD groups for decompensation and liver-related death [HR 2.80 (95% CI 1.52, 5.17; HR 2.34 (95% CI 1.14, 4.83), respectively].

DISCUSSION

MAC was strongly and independently associated with cirrhosis, liver decompensation, liver-related death, and overall death. Surprisingly, stratification results demonstrated comparable or stronger associations among those with non-NAFLD etiology. These findings suggest abdominal aortic calcification may predict liver disease severity and clinical outcomes in patients with CLD.

Bilirubin influences the predictive effect of body mass index on hospital mortality in critically ill patients

Introduction

Body mass index (BMI) can predict mortality in critically ill patients. Moreover, mortality is related to increased bilirubin levels. Thus, herein, we aimed to investigate the effect of bilirubin levels on the usefulness of BMI in predicting mortality in critically ill patients.

Methods

Data were extracted from the Medical Information Mart for Intensive Care (MIMIC IV) database. Patients were divided into two groups according to their total bilirubin levels within 24 h. Cox proportional hazard regression models were applied to obtain adjusted hazard ratios and 95 % confidence intervals for the correlation between BMI categories and hospital mortality. The dose-response relationship was flexibly modeled using a restricted cubic spline (RCS) with three knots.

Results

Of the 14376 patients included, 3.4 % were underweight, 29.3 % were of normal body weight, 32.2 % were overweight, and 35.1 % were obese. For patients with total bilirubin levels <2 mg/dL, hospital mortality was significantly lower in patients with obesity than in normal body weight patients (p < 0.05). However, the opposite results were observed for patients with total bilirubin levels ≥2 mg/dL. The Cox proportional hazard regression models suggested that the risk of death was lower in patients with overweightness and obesity than in normal body weight patients when the total bilirubin levels were <2 mg/dL, but not in the other case (total bilirubin levels ≥2 mg/dL). RCS analyses showed that, for patients with total bilirubin levels <2 mg/dL, the risk of death gradually decreased with increasing BMI. Conversely, for patients with total bilirubin levels ≥2 mg/dL, this risk did not decrease with increasing BMI until reaching obesity, after which it increased rapidly.

Conclusion

BMI predicted the risk of death differently in critically ill patients with different bilirubin levels.

Crosstalk between Epigenetics and Metabolic Reprogramming in Metabolic Dysfunction-Associated Steatotic Liver Disease-Induced Hepatocellular Carcinoma: A New Sight

Epigenetic and metabolic reprogramming alterations are two important features of tumors, and their reversible, spatial, and temporal regulation is a distinctive hallmark of carcinogenesis. Epigenetics, which focuses on gene regulatory mechanisms beyond the DNA sequence, is a new entry point for tumor therapy. Moreover, metabolic reprogramming drives hepatocellular carcinoma (HCC) initiation and progression, highlighting the significance of metabolism in this disease. Exploring the inter-regulatory relationship between tumor metabolic reprogramming and epigenetic modification has become one of the hot directions in current tumor metabolism research. As viral etiologies have given way to metabolic dysfunction-associated steatotic liver disease (MASLD)-induced HCC, it is urgent that complex molecular pathways linking them and hepatocarcinogenesis be explored. However, how aberrant crosstalk between epigenetic modifications and metabolic reprogramming affects MASLD-induced HCC lacks comprehensive understanding. A better understanding of their linkages is necessary and urgent to improve HCC treatment strategies. For this reason, this review examines the interwoven landscape of molecular carcinogenesis in the context of MASLD-induced HCC, focusing on mechanisms regulating aberrant epigenetic alterations and metabolic reprogramming in the development of MASLD-induced HCC and interactions between them while also updating the current advances in metabolism and epigenetic modification-based therapeutic drugs in HCC.

The Influence of Diet and Its Components on the Development and Prevention of Hepatocellular Carcinoma (HCC)

Hepatocellular carcinoma (HCC) is diagnosed annually in nearly a million people worldwide, with approximately half of them being diagnosed at an advanced stage of the disease. Non-infectious risk factors for the development of HCC include an unbalanced lifestyle, including poor dietary choices characterized by a low intake of antioxidants, such as vitamins E and C, selenium, and polyphenols, as well as an excessive consumption of energy and harmful substances. Repeated bad dietary choices that contribute to an unbalanced lifestyle lead to the accumulation of fatty substances in the liver and to it entering an inflammatory state, which, without intervention, results in cirrhosis, the main cause of HCC. This review of the English language literature aims to present the food components that, when included in the daily diet, reduce the risk of developing HCC, as well as identifying foods that may have a carcinogenic effect on liver cells.

Mechanisms of hepatic steatosis in chickens: integrated analysis of the host genome, molecular phenomics and gut microbiome

Hepatic steatosis is the initial manifestation of abnormal liver functions and often leads to liver diseases such as nonalcoholic fatty liver disease in humans and fatty liver syndrome in animals. In this study, we conducted a comprehensive analysis of a large chicken population consisting of 705 adult hens by combining host genome resequencing; liver transcriptome, proteome, and metabolome analysis; and microbial 16S ribosomal RNA gene sequencing of each gut segment. The results showed the heritability (h2 = 0.25) and duodenal microbiability (m2 = 0.26) of hepatic steatosis were relatively high, indicating a large effect of host genetics and duodenal microbiota on chicken hepatic steatosis. Individuals with hepatic steatosis had low microbiota diversity and a decreased genetic potential to process triglyceride output from hepatocytes, fatty acid β-oxidation activity, and resistance to fatty acid peroxidation. Furthermore, we revealed a molecular network linking host genomic variants (GGA6: 5.59-5.69 Mb), hepatic gene/protein expression (PEMT, phosphatidyl-ethanolamine N-methyltransferase), metabolite abundances (folate, S-adenosylmethionine, homocysteine, phosphatidyl-ethanolamine, and phosphatidylcholine), and duodenal microbes (genus Lactobacillus) to hepatic steatosis, which could provide new insights into the regulatory mechanism of fatty liver development.

Lean nonalcoholic fatty liver disease and sarcopenia

Nonalcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases in the world. The risk factor for NAFLD is often considered to be obesity, but it can also occur in people with lean type, which is defined as lean NAFLD. Lean NAFLD is commonly associated with sarcopenia, a progressive loss of muscle quantity and quality. The pathological features of lean NAFLD such as visceral obesity, insulin resistance, and metabolic inflammation are inducers of sarcopenia, whereas loss of muscle mass and function further exacerbates ectopic fat accumulation and lean NAFLD. Therefore, we discussed the association of sarcopenia and lean NAFLD, summarized the underlying pathological mechanisms, and proposed potential strategies to reduce the risks of lean NAFLD and sarcopenia in this review.