Recent advances in lean NAFLD

Steatotic liver disease among lean and non-lean individuals in Southern Lao PDR: a cross-sectional study of risk factors

BACKGROUND

Steatotic liver disease (SLD) prevalence is rising worldwide, linked to insulin resistance and obesity. SLD prevalence can surpass 10% even among those with normal weight. In Lao People's Democratic Republic (Lao PDR), where Opisthorchis viverrini (OV) trematode infection and type 2 diabetes mellitus (T2DM) are common, infection related liver morbidity such as cholangiocarcinoma (CCA) is high, but data on SLD prevalence is lacking. The objective of this study was to estimate the prevalence and explore determinants of SLD in rural southern Lao PDR for lean and non-lean populations.

METHOD

A cross-sectional community-based study assessed SLD prevalence using abdominal ultrasonography (US). Factors investigated for association with SLD were identified by interview, serological tests (Hepatitis B surface antigen (HBsAg); lipids and HbA1c), anthropometrical measurements, and parasitological assessments (OV infection). Uni- and multivariable logistic regression analyses with SLD as endpoint were conducted separately for lean (body mass index (BMI) <23.0 kg/m2) and non-lean (BMI ≥ 23.0 kg/m2) participants.

RESULT

2,826 participants were included. SLD prevalence was 27.1% (95% confidence interval (95% CI) 24.0%-30.4%), higher among non-lean (39.8%) than lean individuals (17.4%). Lean individuals with OV infection had a statistically significant association with lower odds of SLD (adjusted odds ratio (aOR) 0.49, 95% CI 0.33 - 0.73). T2DM showed a significant positive association with SLD in both lean (aOR 3.58, 95% CI 2.28 - 5.63) and non-lean individuals (aOR 3.31, 95% CI 2.31 - 4.74) while dyslipidemia was significantly associated only in the non-lean group (aOR 1.83, 95% CI 1.09 - 3.07). Females participants exhibited elevated odds of SLD in both lean (aOR 1.43, 95% CI 1.02 - 2.01) and non-lean SLD (aOR 1.50, 95% CI 1.12 - 2.01).

CONCLUSION

SLD prevalence is notably high among Laotian adults in rural areas, particularly in females and in non-lean individuals. Lean individuals with OV infection exhibited lower SLD prevalence. SLD was more prevalent in individuals with T2DM, independent of BMI. SLD adds to the burden of infection-related liver morbidity in Lao PDR.

From non-alcoholic fatty liver disease to metabolic-associated steatotic liver disease: Rationale and implications for the new terminology

Non-alcoholic fatty liver disease (NAFLD) was the term first used to describe hepatic steatosis in patients with the metabolic syndrome who did not consume excess amounts of alcohol. Alcoholic liver disease (ALD) has many similarities to NAFLD in both pathogenesis and histology. This entity is now the most prevalent chronic liver disease worldwide as a consequence of the epidemic of obesity. Attempts to incorporate the importance of the metabolic syndrome in the development of steatosis resulted in the renaming of NAFLD as metabolic-associated fatty liver disease. This new term, however, has the disadvantage of the use of terms that may be perceived as derogatory. The terms fatty and non-alcoholic have negative connotations in many cultures. In addition, non-alcoholic is not usually a term applicable to pediatric cases of hepatic steatosis. Recently, an international collaborative effort, with participants from 56 countries, after a global consultation process, recommended to change the nomenclature to steatotic liver disease -including metabolic dysfunction- associated steatotic liver disease, metabolic-associated steatohepatitis and metabolic dysfunction-associated ALD. The new terminology is consistent with most of the previously published epidemiological studies and will have a major impact on research into diagnosis, prognosis and treatment.

Liver Steatosis is Prevalent in Lean People With HIV and Associated With Exposure to Antiretroviral Treatment-A Cross-sectional Study

Background

Steatotic liver disease is suggested to have a higher prevalence and severity in people with HIV (PHIV), including in those with a normal body mass index (BMI). In this study, we used data from the 2000HIV cohort to (1) assess the prevalence of liver steatosis and fibrosis in lean versus overweight/obese PHIV and (2) assess associations in these subgroups between steatosis and fibrosis with traditional risk factors and HIV-specific characteristics.

Methods

The 2000HIV study cohort comprises 1895 virally suppressed PHIV that were included between 2019 and 2021 in 4 HIV treatment centers in the Netherlands. The majority (58.5%) underwent vibration-controlled transient elastography for the assessment of liver steatosis and fibrosis. The prevalence of steatosis (controlled attenuation parameter ≥263 dB/m) and fibrosis (liver stiffness measurement ≥7.0 kPa) was estimated. Multiple factors including HIV characteristics and antiretroviral drugs were tested in a logistic regression model for association with steatosis and fibrosis. Analyses were performed separately for lean (Asian descent: BMI < 23 kg/m2, other descent: BMI < 25 kg/m2) and overweight/obese (other BMI) participants.

Results

Of 1050 PHIV including 505 lean and 545 overweight/obese PHIV, liver steatosis was observed in 37.7% of the overall study population, 19.7% of lean, and 54% of overweight/obese PHIV, whereas fibrosis was observed in 9.0% of the overall study population, 5.9% of lean, and 12.0% of overweight/obese PHIV.All associations with fibrosis and most associations with steatosis concerned metabolic factors such as type 2 diabetes mellitus (overall population: adjusted odds ratio [aOR] for steatosis: 2.3 [1.21-4.4], P = .011; aOR for fibrosis: 3.7 [1.82-7.53], P < .001). Furthermore, in lean PLHIV, liver steatosis was associated with CD4 and CD8 counts at enrollment, dual therapy, and history of treatment with raltegravir (aOR: 3.6 [1.53-8.47], P = .003), stavudine (aOR: 3.73 [1.69-8.2], P = .001), and indinavir (aOR: 3.86 [1.59-9.37], P = .003). These associations were not observed in overweight/obese PHIV.

Conclusions

Liver steatosis was highly prevalent, affecting approximately one-fifth of lean PHIV and half of overweight/obese PHIV. Fibrosis was observed in a minority. Both steatosis and fibrosis were associated with traditional metabolic risk factors. In addition, (prior) exposure to specific antiretroviral drugs was associated liver steatosis in lean, but not in overweight/obese PHIV. Implementing increased screening protocols could enhance the identification of steatotic liver disease in lean PHIV.

Six-gene prognostic signature for non-alcoholic fatty liver disease susceptibility using machine learning

BACKGROUND

nonalcoholic fatty liver disease (NAFLD) is a common liver disease affecting the global population and its impact on human health will continue to increase. Genetic susceptibility is an important factor influencing its onset and progression, and there is a lack of reliable methods to predict the susceptibility of normal populations to NAFLD using appropriate genes.

METHODS

RNA sequencing data relating to nonalcoholic fatty liver disease was analyzed using the "limma" package within the R software. Differentially expressed genes were obtained through preliminary intersection screening. Core genes were analyzed and obtained by establishing and comparing 4 machine learning models, then a prediction model for NAFLD was constructed. The effectiveness of the model was then evaluated, and its applicability and reliability verified. Finally, we conducted further gene correlation analysis, analysis of biological function and analysis of immune infiltration.

RESULTS

By comparing 4 machine learning algorithms, we identified SVM as the optimal model, with the first 6 genes (CD247, S100A9, CSF3R, DIP2C, OXCT 2 and PRAMEF16) as predictive genes. The nomogram was found to have good reliability and effectiveness. Six genes' receiver operating characteristic curves (ROC) suggest an essential role in NAFLD pathogenesis, and they exhibit a high predictive value. Further analysis of immunology demonstrated that these 6 genes were closely connected to various immune cells and pathways.

CONCLUSION

This study has successfully constructed an advanced and reliable prediction model based on 6 diagnostic gene markers to predict the susceptibility of normal populations to NAFLD, while also providing insights for potential targeted therapies.

The Interplay between Endocrine-Disrupting Chemicals and the Epigenome towards Metabolic Dysfunction-Associated Steatotic Liver Disease: A Comprehensive Review

Metabolic dysfunction-associated steatotic liver disease (MASLD), described as the most prominent cause of chronic liver disease worldwide, has emerged as a significant public health issue, posing a considerable challenge for most countries. Endocrine-disrupting chemicals (EDCs), commonly found in daily use items and foods, are able to interfere with nuclear receptors (NRs) and disturb hormonal signaling and mitochondrial function, leading, among other metabolic disorders, to MASLD. EDCs have also been proposed to cause transgenerationally inherited alterations leading to increased disease susceptibility. In this review, we are focusing on the most prominent linking pathways between EDCs and MASLD, their role in the induction of epigenetic transgenerational inheritance of the disease as well as up-to-date practices aimed at reducing their impact.

Update in lean metabolic dysfunction-associated steatotic liver disease

BACKGROUND

A new nomenclature consensus has emerged for liver diseases that were previously known as non-alcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD). They are now defined as metabolic dysfunction-associated steatotic liver disease (MASLD), which includes cardiometabolic criteria in adults. This condition, extensively studied in obese or overweight patients, constitutes around 30% of the population, with a steady increase worldwide. Lean patients account for approximately 10%-15% of the MASLD population. However, the pathogenesis is complex and is not well understood.

AIM

To systematically review the literature on the diagnosis, pathogenesis, characteristics, and prognosis in lean MASLD patients and provide an interpretation of these new criteria.

METHODS

We conducted a comprehensive database search on PubMed and Google Scholar between January 2012 and September 2023, specifically focusing on lean NAFLD, MAFLD, or MASLD patients. We include original articles with patients aged 18 years or older, with a lean body mass index categorized according to the World Health Organization criteria, using a cutoff of 25 kg/m2 for the general population and 23 kg/m2 for the Asian population.

RESULTS

We include 85 studies in our analysis. Our findings revealed that, for lean NAFLD patients, the prevalence rate varied widely, ranging from 3.8% to 34.1%. The precise pathogenesis mechanism remained elusive, with associations found in genetic variants, epigenetic modifications, and adaptative metabolic response. Common risk factors included metabolic syndrome, hypertension, and type 2 diabetes mellitus, but their prevalence varied based on the comparison group involving lean patients. Regarding non-invasive tools, Fibrosis-4 index outperformed the NAFLD fibrosis score in lean patients. Lifestyle modifications aided in reducing hepatic steatosis and improving cardiometabolic profiles, with some medications showing efficacy to a lesser extent. However, lean NAFLD patients exhibited a worse prognosis compared to the obese or overweight counterpart.

CONCLUSION

MASLD is a complex disease comprising epigenetic, genetic, and metabolic factors in its pathogenesis. Results vary across populations, gender, and age. Limited data exists on clinical practice guidelines for lean patients. Future studies employing this new nomenclature can contribute to standardizing and generalizing results among lean patients with steatotic liver disease.

A genetic mouse model of lean-NAFLD unveils sexual dimorphism in the liver-heart axis

Lean patients with NAFLD may develop cardiac complications independently of pre-existent metabolic disruptions and comorbidities. To address the underlying mechanisms independent of the development of obesity, we used a murine model of hepatic mitochondrial deficiency. The liver-heart axis was studied as these mice develop microvesicular steatosis without obesity. Our results unveil a sex-dependent phenotypic remodeling beyond liver damage. Males, more than females, show fasting hypoglycemia and increased insulin sensitivity. They exhibit diastolic dysfunction, remodeling of the circulating lipoproteins and cardiac lipidome. Conversely, females do not manifest cardiac dysfunction but exhibit cardiometabolic impairments supported by impaired mitochondrial integrity and β-oxidation, remodeling of circulating lipoproteins and intracardiac accumulation of deleterious triglycerides. This study underscores metabolic defects in the liver resulting in significant sex-dependent cardiac abnormalities independent of obesity. This experimental model may prove useful to better understand the sex-related variability, notably in the heart, involved in the progression of lean-NAFLD.

New aspects characterizing non-obese NAFLD by the analysis of the intestinal flora and metabolites using a mouse model

Non-alcoholic fatty liver disease (NAFLD) is a major public health problem due to the high incidence affecting approximately one-third of the world's population. NAFLD is usually linked to obesity and excessive weight. A subset of patients with NAFLD expresses normal or low body mass index; thus, the condition is called non-obese NAFLD or lean NAFLD. However, patients and healthcare professionals have little awareness and understanding of NAFLD in non-obese individuals. Furthermore, preclinical results from non-obese animal models with NAFLD are unclear. Gut microbiota and their metabolites in non-obese/lean-NAFLD patients differ from those in obese NAFLD patients. Therefore, we analyzed the biochemical indices, intestinal flora, and intestinal metabolites in a non-obese NAFLD mouse model established using a methionine-choline-deficient (MCD) diet. The significantly lean MCD mice had a remarkable fatty liver with lower serum triglyceride and free fatty acid levels, as well as higher alanine transaminase and aspartate transaminase levels than normal mice. 16S RNA sequencing of fecal DNA showed that the overall richness and diversity of the intestinal flora decreased in MCD mice, whereas the Firmicutes:Bacteroidota ratio was increased. g_Tuzzerella, s_Bifidobacterium pseudolongum, and s_Faecalibaculum rodentium were the predominant species in non-obese NAFLD mice. Fecal metabolomics using liquid chromatography-tandem mass spectrometry revealed the potential biomarkers for the prognosis and diagnosis of non-obese NAFLD, including high levels of tyramine glucuronide, 9,12,13-TriHOME, and pantetheine 4'-phosphate, and low levels of 3-carbamoyl-2-phenylpropionaldehyde, N-succinyl-L,L-2,6-diaminopimelate, 4-methyl-5-thiazoleethanol, homogentisic acid, and estriol. Our findings could be useful to identify and develop drugs to treat non-obese NAFLD and lean NAFLD.

IMPORTANCE

Patients and healthcare professionals have little awareness and understanding of NAFLD in non-obese individuals. In fact, about 40% of people with NAFLD worldwide are non-obese, and nearly one-fifth are lean. Lean NAFLD unfortunately may be unnoticed for years and remains undetected until hepatic damage is advanced and the prognosis is compromised. This study focused on the lean NAFLD, screened therapeutic agents, and biomarkers for the prognosis and diagnosis using MCD-induced male C57BL/6J mice. The metabolites tyramine glucuronide, 9,12,13-TriHOME, and pantetheine 4'-phosphate, together with the predominant flora including g_Tuzzerella, s_Bifidobacterium pseudolongum, and s_Faecalibaculum rodentium, were specific in non-obese NAFLD mice and might be used as targets for non-obese NAFLD drug exploration. This study is particularly significant for non-obese NAFLDs that need to be more actively noticed and vigilant.

Early and accurate diagnosis of steatotic liver by artificial intelligence (AI)-supported ultrasonography

OBJECTIVES

Steatotic liver disease is the most frequent chronic liver disease worldwide. Ultrasonography (US) is commonly employed for the assessment and diagnosis. Few information is available on the possible use of artificial intelligence (AI) to ameliorate the diagnostic accuracy of ultrasonography.

MATERIALS AND METHODS

An AI-based algorithm was developed using a dataset of US images. We prospectively enrolled 134 patients for algorithm validation. Patients underwent abdominal US and Proton Density Fat Fraction MRI scans (MRI-PDFF), assumed as reference technique. The hepatorenal index was manually calculated (HRIM) by 4 operators. An automatic hepatorenal index (HRIA) was obtained by the algorithm. The accuracy of HRIA to discriminate steatosis grades was evaluated by ROC analysis using MRI-PDFF cut-offs.

RESULTS

Overweight was 40 % of subjects (BMI 26.4 kg/cm2). The median HRIA was 1.11 (IQR 0.32) and the average of 4 manually calculated HRIM was 1.08 (IQR 0.26), with a 15 % inter-operator variability. Both HRIA (R = 0.79, P < 0.0001) and HRIM (R = 0.69, P < 0.0001) significantly correlated with liver fat percentage (MRI-PDFF). According to MRI-PDFF, 32 % of enrolled subjects had steatosis. Discrimination capacity by AUC between patient with steatosis and patient without steatosis was better for HRIA than HRIM (AUC: 0.87 vs. 0.82, respectively). ROC analysis showed an AUC = 0.98 for HRIA with 1.64 cut-off in distinguishing between mild and moderate/severe groups.

CONCLUSIONS

The use of AI improves accuracy and speed of ultrasonography in the diagnosis of liver steatosis. Further studies should evaluate the routine use of this technique in the management of liver steatosis at high cardio-metabolic risk.

From NAFLD to MASLD: When metabolic comorbidity matters

INTRODUCTION AND OBJECTIVES

In a recent development, a cohort of hepatologists has proposed altering the nomenclature of non-alcoholic fatty liver disease (NAFLD) to metabolic-associated steatotic liver disease (MASLD), accompanied by modified diagnostic criteria. Our objective was to investigate the effect of the revised definition on identifying significant hepatic fibrosis.

PATIENTS AND METHODS

From Jan 2009 to Dec 2022, a total of 428 patients with biopsy-proven hepatic steatosis were diagnosed with NAFLD. Patients were classified into subgroups according to MASLD and Cryptogenic-SLD diagnostic criteria. The clinical pathological features were compared between these two groups. Risk factors for significant fibrosis were analysed in the MASLD group. In total, 329 (76.9 %) patients were diagnosed with MASLD, and 99 (23.1 %) were diagnosed with Cryptogenic-SLD.

RESULTS

Those with MASLD exhibited a higher degree of disease severity regarding histology features than Cryptogenic-SLD. The prevalence of significant fibrosis increased from 13 % to 26.6 % for one and two criteria present to 42.5 % for meeting three or more cardiometabolic risk factor (CMRF) criteria (p = 0.001). ALB (aOR:0.94,95 %CI:0.90-1.00; p = 0.030), lower levels of PLT (aOR:0.99, 95 %CI:0.99-1.00; p < 0.001), and more metabolic comorbidities (aOR:1.42,95 %CI:1.14-1.78; p = 0.012) were independent risk factors of significant fibrosis in MASLD.

CONCLUSIONS

The new nomenclature of MASLD and SLD is more applicable to identifying significant fibrosis than NAFLD. Patients with three or more cardiometabolic risk factors are at higher risk of fibrosis.

Association between TyG index trajectory and new-onset lean NAFLD: a longitudinal study

Objective

The purpose of this manuscript is to identify longitudinal trajectories of changes in triglyceride glucose (TyG) index and investigate the association of TyG index trajectories with risk of lean nonalcoholic fatty liver disease (NAFLD).

Methods

Using data from 1,109 participants in the Health Management Cohort longitudinal study, we used Latent Class Growth Modeling (LCGM) to develop TyG index trajectories. Using a Cox proportional hazard model, the relationship between TyG index trajectories and incident lean NAFLD was analyzed. Restricted cubic splines (RCS) were used to visually display the dose-response association between TyG index and lean NAFLD. We also deployed machine learning (ML) via Light Gradient Boosting Machine (LightGBM) to predict lean NAFLD, validated by receiver operating characteristic curves (ROCs). The LightGBM model was used to create an online tool for medical use. In addition, NAFLD was assessed by abdominal ultrasound after excluding other liver fat causes.

Results

The median age of the population was 46.6 years, and 440 (39.68%) of the participants were men. Three distinct TyG index trajectories were identified: "low stable" (TyG index ranged from 7.66 to 7.71, n=206, 18.5%), "moderate stable" (TyG index ranged from 8.11 to 8.15, n=542, 48.8%), and "high stable" (TyG index ranged from 8.61 to 8.67, n=363, 32.7%). Using a "low stable" trajectory as a reference, a "high stable" trajectory was associated with an increased risk of lean-NAFLD (HR: 2.668, 95% CI: 1.098-6.484). After adjusting for baseline age, WC, SBP, BMI, and ALT, HR increased slightly in "moderate stable" and "high stable" trajectories to 1.767 (95% CI:0.730-4.275) and 2.668 (95% CI:1.098-6.484), respectively. RCS analysis showed a significant nonlinear dose-response relationship between TyG index and lean NAFLD risk (χ2 = 11.5, P=0.003). The LightGBM model demonstrated high accuracy (Train AUC 0.870, Test AUC 0.766). An online tool based on our model was developed to assist clinicians in assessing lean NAFLD risk.

Conclusion

The TyG index serves as a promising noninvasive marker for lean NAFLD, with significant implications for clinical practice and public health policy.

Association between weight-adjusted waist index and non-alcoholic fatty liver disease: a population-based study

BACKGROUND

Obesity is the most important driver of non-alcoholic fatty liver disease (NAFLD); nevertheless, the relationship of weight-adjusted waist index (WWI), a new obesity index, with NAFLD is unclear.

METHODS

This retrospective study used data from the NAGALA project from 1994 to 2016. WWI values were calculated using waist circumference (WC) and weight measurements of the participants. Three stepwise adjusted logistic regression models were developed to assess the relationship of WWI with NAFLD in the whole population and in both sexes. Additionally, we also conducted a series of exploratory analysis to test the potential impact of body mass index (BMI), age, smoking status and exercise habits on the association of WWI with NAFLD. Receiver operating characteristic (ROC) curves were used to estimate cut-off points for identifying NAFLD in the entire population and in both sexes.

RESULTS

The current study included a population of 11,805 individuals who participated in health screenings, including 6,451 men and 5,354 women. After adjusting for all non-collinear variables in the multivariable logistic regression model, we found a significant positive correlation of WWI with NAFLD. For each unit increase in WWI, the risk of NAFLD increased by 72% in the entire population, by 84% in men, and by 63% in women. Furthermore, subgroup analyses revealed no significant discrepancies in the correlation of WWI with NAFLD across individuals with varying ages, exercise habits, and smoking status (all P-interaction > 0.05), except for different BMI groups (P-interaction < 0.05). Specifically, compared to the overweight/obese group, the relationship of WWI with NAFLD was significantly stronger in the non-obese group, especially in non-obese men. Finally, based on the results of ROC analysis, we determined that the WWI cut-off point used to identify NAFLD was 9.7675 in men and 9.9987 in women.

CONCLUSIONS

This study is the first to establish a positive correlation between WWI and NAFLD. Moreover, assessing the influence of WWI on NAFLD in individuals without obesity may yield more valuable insights compared to those who are overweight or obese.

Associations of serum uric acid levels and anthropometric parameters with non-alcoholic fatty liver disease in healthy individuals: innovative insights from a cross-sectional study

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD is a spectrum of liver disease with a rising prevalence, ranging from simple steatosis to steatohepatitis and cirrhosis, where a significant minority face potential complications. Determining the predictive markers plays a crucial role. This study examined the relationship between serum uric acid (SUA) levels and NAFLD in healthy individuals and identified potential other predictors.

MATERIAL AND METHODS

A cohort of 2162 healthy participants attending routine check-up visits between February 2021 and May 2023 were included. Participants underwent abdominal ultrasound, uric acid measurements, and anthropometric assessments by TANITA. NAFLD was graded using a "hepatic steatosis score." Statistical analysis included nonparametric tests, chi-squared tests, Fisher's exact test, ROC curve analysis, and logistic regression.

RESULTS

The median age was 45 years (range:18-65). 1017 were male, and 1145 were female. Among the participants, 53.9%, 26.3%, 17.9%, and 1.9% exhibited Grade 0, 1, 2, and 3 hepatic steatosis, respectively. ROC analysis showed 80.0% sensitivity and 78.8% specificity for detecting grade 2 or higher hepatic steatosis with a cutoff value of 5.21 mg/dl of SUA (AUC = 0.82, p < 0.001, 95%CI 0.79-0.84). There were significant associations between elevated uric acid levels and NAFLD. Participants with higher body fat percentages, BMI values, and waist-to-hip ratios also demonstrated an increased prevalence of steatosis. Gender significantly influenced liver steatosis, with males exhibiting higher grades compared to females. Logistic regression analysis highlighted positive associations between NAFLD and body fat percentage, waist-to-hip ratio, and uric acid levels. Each unit increase in uric acid levels corresponded to a 2.5-fold increase in the odds of NAFLD (p < 0.001, 95% CI = 2.20-2.84).

CONCLUSION

Our findings suggest a significant relationship between serum uric acid levels and NAFLD in healthy individuals. Elevated uric acid levels, in conjunction with other anthropometric parameters, may serve as potential predictive markers for NAFLD.

Unique Genetic Features of Lean NAFLD: A Review of Mechanisms and Clinical Implications

Non-alcoholic fatty liver disease (NAFLD) affects 25% of the global population. About 20% have a normal body mass index (BMI) and a variant known as lean NAFLD. Unlike typical NAFLD cases associated with obesity and diabetes, lean NAFLD causes liver disease by mechanisms not related to excess weight or insulin resistance. Genetic disorders are among the major factors in developing lean NAFLD, and genome-wide association studies have identified several genes associated with the condition. This review aims to increase awareness by describing the genetic markers linked to NAFLD and the defects involved in developing lean NAFLD.

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

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

Association between hypoglycemic agent use and the risk of occurrence of nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus

Nonalcoholic fatty liver disease (NAFLD) is a growing health concern with increasing prevalence and associated health impacts. Although no approved drugs are available for the NAFLD treatment, several hypoglycemic agents have been investigated as promising therapeutic agents. We aimed to compare the risk of occurrence of NAFLD with respect to the use of different hypoglycemic agents in patients with type 2 diabetes. This retrospective cohort study used data from the National Health Insurance Service-National Sample Cohort of South Korea. Participants newly diagnosed with type 2 diabetes (2003-2019) were included in this study. Two new user-active comparator cohorts were assembled: Cohort 1, new users of thiazolidinediones (TZD) and dipeptidyl peptidase-4 inhibitors (DPP-4i), and Cohort 2, new users of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and DPP-4i. The occurrence of NAFLD was defined based claims that include diagnostic codes. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models in 1:3 propensity score (PS)-matched cohorts. For 65,224 patients newly diagnosed with type 2 diabetes, the overall prevalence of NAFLD was 42.6%. The PS-matched Cohort 1 included 6,351 and 2,117 new users of DPP-4i and TZD, respectively. Compared to DPP-4i, TZD use was associated with the decreased risk of NAFLD (HR, 0.66; 95% CI: 0.55-0.78). Cohort 2 consisted of 6,783 and 2,261 new users of DPP-4i and SGLT-2i, respectively; SGLT-2i use was associated with a decreased risk of NAFLD (HR, 0.93; 95% CI: 0.80-1.08). This population-based cohort study supports the clinical implications of prioritizing TZD and SGLT-2i over DPP-4i in reducing the risk of occurrence of NAFLD in patients with type 2 diabetes. However, the findings lacked statistical significance, highlighting the need for further verification studies.

Optimization of preparation method of hepatoprotective active components from Coreopsis tinctoria Nutt. and its action mechanism in vivo

Capitula of Coreopsis tinctoria are widely used as a flower tea with great health benefits due to rich content of flavonoids and phenolic acids. The hepatoprotective effect of C. tinctoria and its bioactive basis have seldom been investigated until now. In the present study, capitula of C. tinctoria were extracted with a method optimized by response surface methodology (RSM) and BoxBehnken design (BBD) and further purified by macroporous resin HPD-300 to obtain a fraction (CE) enriched with flavonoids and phenolic acids. The contents of the four most abundant compounds, isookanin-7-O-β-d-glucoside (1), quercetigetin-7-O-β-d-glucoside (2), okanin (3), and marein (4), were determined by HPLC as 9.98, 5.21, 41.78 and 1.85 mg/g, respectively. Seventy-four compounds including fifity-five flavonoids, fifteen organic acids (twelve of them were phenolic compounds), and three coumarins were tentatively identified in CE by LC-HRMS/MS. In vivo hepatoprotective effect and potential mechanism of CE were studied with a high-fat diet-induced NASH mouse model. CE administration decreased the amount of weight gain, hepatic lipid, and sequentially improved dyslipidemia, inflammation, oxidative stress, and IR in HFD-fed mice. Molecular data revealed that CE inhibited hepatic inflammation by reducing NFκB/iNOS/COX-2/NLRP3/MAPK in the liver tissues and ameliorated oxidative stress by activating the Nrf2/HO-1 pathway. Modulation of inflammation and oxidative stress with CE may represent a promising target for the treatment of NAFLD and provide insight into the mechanism by which CE protects against obesity.

Genistein upregulates AHR to protect against environmental toxin-induced NASH by inhibiting NLRP3 inflammasome activation and reconstructing antioxidant defense mechanisms

We have previously proven that the environmental toxin could accelerate the development and progression of nonalcoholic steatohepatitis (NASH). However, the underlying mechanism associated with such excessive inflammation hasn't been fully illustrated. Although Genistein has been well accepted for its capability in anti-inflammation and anti-oxidation, its effect in ameliorating contaminants-induced NASH still needs to be identified. In this study, using chickens and primary chicken hepatocytes as models, we found that NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome were over-activated in bromoacetic acid (BAA, one of the typical environmental toxins)-induced NASH, characterized by the infiltration of inflammatory cell, and the increase of NLRP3, Caspase-1 p20, and cytokines (IL-1β, IL-18) expressions. Interestingly, genistein treatment could recover these changes, with the signs of restored activities of anti-oxidases, decreased expressions of NLRP3 inflammasome components, and increased levels of elements in phase I metabolic system. The detailed mechanism was that, via up-regulating aryl hydrocarbon receptor (AHR), genistein lifted mRNA levels of Cyp1-related genes to reconstruct cytochrome P450 (CYP450) systems, and the raised AHR negatively regulated NLRP3 inflammasome activity to relieve inflammation. More important, the interaction and co-localization between AHR and NLRP3 was first proved, and genistein could promote the levels of AHR that interacted with NLRP3, which thereafter blocked the activation of NLRP3 inflammasome. Conclusively, in this research, we confirmed the AHR-dependent protective role of genistein in environmental toxin-linked NASH, which shed light on the potential precautions for contaminants-induced NASH.

Partial Replacement of Diet with Dehulled Adlay Ameliorates Hepatic Steatosis, Inflammation, Oxidative Stress, and Gut Dysbiosis in Rats with Nonalcoholic Fatty Liver Disease

The prevalence of nonalcoholic fatty liver disease (NAFLD) has been increasing worldwide, and the average age at NAFLD diagnosis has been decreasing. Although some components of adlay can ameliorate lipid metabolism, oxidative stress, inflammatory response, and gut microbiota, few studies have explored the effects of the dietary intake of intact dehulled adlay on liver diseases. Therefore, in this study, we investigated the effects of the dietary intake of dehulled adlay on NAFLD progression and explored the potential underlying mechanisms. Rats were randomized into a control group; a high-fat, high-sucrose diet (60% total energy derived from fat and 9.4% from sucrose)-induced NAFLD group (N); or a high-fat, high-sucrose diet with dehulled adlay group (received the same amounts of dietary fiber and total energy as did the N group). The experimental duration was 16 weeks. The diet containing dehulled adlay mitigated hepatic fat accumulation, proinflammatory cytokine levels, and oxidative stress by regulating the AMPK-Nrf2-NLRP3 inflammasome pathway and ferroptosis. Additionally, the dietary intake of dehulled adlay modulated the composition of the gut microbiota. In conclusion, a diet containing dehulled adlay may decelerate the progression of NAFLD by ameliorating hepatic steatosis, inflammation, oxidative stress, and gut dysbiosis.

HOMA-IR is an effective biomarker of non-alcoholic fatty liver disease in non-diabetic population

OBJECTIVES

This study aimed to investigate the correlation between homeostasis model assessment of insulin resistance (HOMA-IR) and non-alcoholic fatty liver disease (NAFLD) in the non-diabetic population and establish its diagnostic efficacy.

METHODS

This observational study involved participants divided into NAFLD and non-NAFLD groups, and baseline data were analyzed. Univariate and multivariate logistic regression analyses were used to correlate HOMA-IR with the risk of NAFLD. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic efficacy of HOMA-IR for NAFLD. Subgroup analyses of non-obese individuals were performed.

RESULTS

Overall, 2234 non-diabetic participants were included. The HOMA-IR was significantly higher in the NAFLD group than in the non-NAFLD group. Multivariate logistic regression analysis showed that HOMA-IR was a strong and independent risk factor for NAFLD after correcting for confounding factors. The area under the ROC curve (AUC) value of HOMA-IR for predicting NAFLD was 0.792. In the non-obese non-diabetic population, HOMA-IR was an independent risk factor for increased risk of lean NAFLD after correcting for confounding factors. The AUC value of HOMA-IR for predicting lean NAFLD was 0.770.

CONCLUSIONS

HOMA-IR is independently associated with the risk of NAFLD in the non-diabetic and non-obese non-diabetic populations and has good diagnostic value.

Altered splicing factor and alternative splicing events in a mouse model of diet- and polychlorinated biphenyl-induced liver disease

Non-alcoholic fatty liver disease (NAFLD) is associated with human environmental exposure to polychlorinated biphenyls (PCBs). Alternative splicing (AS) is dysregulated in steatotic liver disease and is regulated by splicing factors (SFs) and N-6 methyladenosine (m6A) modification. Here integrated analysis of hepatic mRNA-sequencing data was used to identify differentially expressed SFs and differential AS events (ASEs) in the livers of high fat diet-fed C57BL/6 J male mice exposed to Aroclor1260, PCB126, Aroclor1260 + PCB126, or vehicle control. Aroclor1260 + PCB126 co-exposure altered 100 SFs and replicate multivariate analysis of transcript splicing (rMATS) identified 449 ASEs in 366 genes associated with NAFLD pathways. These ASEs were similar to those resulting from experimental perturbations in m6A writers, readers, and erasers. These results demonstrate specific hepatic SF and AS regulatory mechanisms are disrupted by HFD and PCB exposures, contributing to the expression of altered isoforms that may play a role in NAFLD progression to NASH.

Hunger & satiety signals: another key mechanism involved in the NAFLD pathway

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent metabolic disease, although prevalence could change according to region, nowadays is considered a public health problem whose real impact on the health system is unknown. NAFLD has a multifactorial and complex pathophysiology, due to this, developing a unique and effective pharmacological treatment has not been successful in reverting or avoiding the progression of this liver disease. Even though NAFLD pathophysiology is known, all actual treatments are focused on modifying or regulating the metabolic pathways, some of which interplay with obesity. It has been known that impairments in hunger and satiety signals are associated with obesity, however, abnormalities in these signals in patients with NAFLD and obesity are not fully elucidated. To describe these mechanisms opens an additional option as a therapeutic target sharing metabolic pathways with NAFLD, therefore, this review aims to describe the hormones and peptides implicated in both hunger-satiety in NAFLD. It has been established that NAFLD pharmacological treatment cannot be focused on a single purpose; hence, identifying interplays that lead to adding or modifying current treatment options could also have an impact on another related outcome such as hunger or satiety signals.

Eight Zhes Decoction ameliorates the lipid dysfunction of nonalcoholic fatty liver disease using integrated lipidomics, network pharmacology and pharmacokinetics

Nonalcoholic fatty liver disease (NAFLD) has developed into the most common chronic liver disease and can lead to liver cancer. Our laboratory previously developed a novel prescription for NAFLD, "Eight Zhes Decoction" (EZD), which has shown good curative effects in clinical practice. However, the pharmacodynamic material basis and mechanism have not yet been revealed. A strategy integrating lipidomics, network pharmacology and pharmacokinetics was used to reveal the active components and mechanisms of EZD against NAFLD. The histopathological results showed that EZD attenuated the degrees of collagen deposition and steatosis in the livers of nonalcoholic steatofibrosis model mice. Furthermore, glycerophospholipid metabolism, arachidonic acid metabolism, glycerolipid metabolism and linoleic acid metabolism with phospholipase A2 group IVA (PLA2G4A) and cytochrome P450 as the core targets and 12,13-cis-epoxyoctadecenoic acid, 12(S)-hydroxyeicosatetraenoic acid, leukotriene B4, prostaglandin E2, phosphatidylcholines (PCs) and triacylglycerols (TGs) as the main lipids were found to be involved in the treatment of NAFLD by EZD. Importantly, naringenin, artemetin, canadine, and bicuculline were identified as the active ingredients of EZD against NAFLD; in particular, naringenin reduces PC consumption by inhibiting the expression of PLA2G4A and thus promotes sufficient synthesis of very-low-density lipoprotein to transport excess TGs in the liver. This research provides valuable data and theoretical support for the application of EZD against NAFLD.

Metabolic-Associated Fatty Liver Disease and Diabetes: A Double Whammy

Metabolic-associated fatty liver disease (MAFLD) is the hepatic manifestation of metabolic syndrome and affects about 55% of people living with diabetes. MAFLD has been shown to be an individual risk factor for cardiovascular disease and its associated mortality. Although common, MAFLD is often underdiagnosed and not given adequate attention during clinical visits. This review highlights the most recent literature available on the evaluation and management of MAFLD in the presence of diabetes. The more recently available antidiabetic agents including glucagon-like peptide-1 analogs and sodium-glucose cotransporter-2 inhibitors have been shown to effectively manage both diabetes and MAFLD.

Inflammatory Bowel Disease Is an Independent Risk Factor for Metabolic Dysfunction-Associated Steatotic Liver Disease in Lean Individuals

BACKGROUND

Despite classical association between metabolic dysfunction-associated steatotic liver disease (MASLD) and obesity, there is increasing evidence on the development of MASLD in lean individuals. The aim of the study was to assess the prevalence and risk factors of MASLD and significant liver fibrosis in lean participants with inflammatory bowel disease (IBD).

METHODS

This was a cross-sectional, case-control study including 300 lean cases with IBD and 80 lean controls without IBD, matched by sex and age. All participants underwent a liver ultrasound, transient elastography, and laboratory tests.

RESULTS

The lean IBD group showed a significantly higher prevalence of MASLD compared with lean non-IBD group (21.3% vs 10%; P = .022), but no differences were observed in the prevalence of significant liver fibrosis (4.7% vs 0.0%; P = 1.000). No differences were found between the prevalence of MASLD in IBD and non-IBD participants who were overweight/obese (66.8% vs 70.8%; P = .442). In addition, the prevalence of MASLD was significantly higher in the overweight/obese IBD group compared with the lean IBD group (P < .001). IBD was an independent risk factor for MASLD in lean participants (odds ratio [OR], 2.71; 95% confidence interval [CI], 1.05-7.01; P = .04), after adjusting for classic metabolic risk factors and prior history of systemic steroid use. Nevertheless, no association between IBD related factors and MASLD was identified in lean IBD participants. When the overweight/obese and lean IBD groups with MASLD were compared, the overweight/obese IBD group with MASLD showed higher levels of the homeostatic model assessment of insulin resistance (OR, 1.49; 95% CI, 1.11-1.98; P = .007) and history of smoking (OR, 4.66; 95% CI, 1.17-18.49; P = .029).

CONCLUSIONS

MASLD prevalence was higher in the lean IBD group compared with lean non-IBD group, independent of classic metabolic risk factors.

Epigenetic Regulation in Lean Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), the most prominent cause of chronic liver disease worldwide, is a rapidly growing epidemic. It consists of a wide range of liver diseases, from steatosis to nonalcoholic steatohepatitis, and predisposes patients to liver fibrosis, cirrhosis, and even hepatocellular carcinoma. NAFLD is strongly correlated with obesity; however, it has been extensively reported among lean/nonobese individuals in recent years. Although lean patients demonstrate a lower prevalence of diabetes mellitus, central obesity, dyslipidemia, hypertension, and metabolic syndrome, a percentage of these patients may develop steatohepatitis, advanced liver fibrosis, and cardiovascular disease, and have increased all-cause mortality. The pathophysiological mechanisms of lean NAFLD remain vague. Studies have reported that lean NAFLD demonstrates a close association with environmental factors, genetic predisposition, and epigenetic modifications. In this review, we aim to discuss and summarize the epigenetic mechanisms involved in lean NAFLD and to introduce the interaction between epigenetic patterns and genetic or non genetic factors. Several epigenetic mechanisms have been implicated in the regulation of lean NAFLD. These include DNA methylation, histone modifications, and noncoding-RNA-mediated gene regulation. Epigenetics is an area of special interest in the setting of lean NAFLD as it could provide new insights into the therapeutic options and noninvasive biomarkers that target this under-recognized and challenging disorder.

Long working hours and increased risks of lean non-alcoholic fatty liver disease among Korean men and women

Despite the increasing prevalence of lean nonalcoholic fatty liver disease (NAFLD), its risk factors are not well established. We examined the association between long working hours and incident NAFLD in lean Korean workers with emphasis on sex-based effect modification. This cohort study involved 46,113 non-overweight (BMI < 23 kg/m²) and NAFLD-free Korean workers (mean age, 35.5 years). Working hours were categorized into 35-40 (reference), 41-52, and ≥ 53 h. The presence of fatty liver and its severity were determined using ultrasonography and NAFLD fibrosis score (NFS), respectively. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using parametric proportional hazards models. Incident cases of 5901 lean NAFLD developed over a median follow-up of 3.8 years. The incidence of lean NAFLD increased with increasing working hours with a stronger association in men than in women (P for interaction < 0.001). For men, multivariable-adjusted HRs (95% CIs) for lean NAFLD in time-dependent models comparing working hours of 41-52 and ≥ 53 h compared to the reference category were 1.17 (1.07-1.28) and 1.25 (1.12-1.39), respectively. The excess relative risk of developing lean NAFLD with intermediate/high NFS was observed in working hours of 41-52 and ≥ 53 h with a corresponding HR of 1.66 (1.13-2.43) and 1.54 (0.94-2.51), respectively. Conversely, no significant associations were found between working hours and incidence of lean NAFLD in women. In conclusion, long working hours were significantly associated with an increased incidence of lean NAFLD and its severe form in men but not in women.

Role of BMI in the relationship between dietary inflammatory index and non-alcoholic fatty liver disease: an intermediary analysis

OBJECTIVE

Previous studies have indicated that a pro-inflammatory diet is associated with non-alcoholic fatty liver disease (NAFLD), but the role of BMI remains ambiguous. We aim to study the intermediary effect of BMI on the relationship between dietary inflammatory properties and NAFLD.

METHODS

A total of 19536 adult participants from the National Health and Nutrition Examination Surveys (NHANES) were included. Dietary inflammatory index (DII) was used to evaluate the dietary inflammatory properties and NAFLD was diagnosed by non-invasive biomarkers. Weighted multivariable logistic regression models estimated ORs and 95% CIs between DII and incidence of NAFLD. Interaction effect between DII and BMI on NAFLD was tested and the mediation analysis of BMI was performed.

RESULTS

Higher DII scores, representing higher inflammatory potential of diet, were positively associated with a higher risk of NAFLD. Compared with the first quartile of DII, people from the second quartile (OR: 1.23 [95% CI: 1.04, 1.46]) to the fourth quartile (OR: 1.59 [95% CI: 1.31, 1.94]) have a higher risk of NAFLD before adjustment for BMI. The overall association was completely mediated by BMI (89.19%).

CONCLUSIONS

Our findings suggested that a higher pro-inflammatory potential diet was associated with a higher prevalence of NAFLD, and this association might be mediated by BMI.

Mechanisms of non-alcoholic fatty liver disease development in normal-weight individuals

While non-alcoholic fatty liver disease (NAFLD) without inflammation or fibrosis is considered a relatively 'benign' disease, non-alcoholic steatohepatitis (NASH), by contrast, is characterized by marked inflammation in addition to lipid accumulation, and may include fibrosis, progression to cirrhosis and hepatocellular carcinoma. Obesity and type II diabetes are frequently associated with NAFLD/NASH; however, a significant number of lean individuals may develop these diseases. Little attention has been paid to the causes and mechanisms contributing to NAFLD development in normal-weight individuals. One of the main causes of NAFLD in normal-weight individuals is the accumulation of visceral and muscular fat and its interaction with the liver. Myosteatosis (triglyceride accumulation in the muscle) induces a loss of muscle by reducing blood flow and insulin diffusion, contributing to NAFLD. Normal-weight patients with NAFLD exhibit higher serum markers of liver damage and C-reactive protein levels, as well as more pronounced insulin resistance, compared to healthy controls. Notably, increased levels of C-reactive protein and insulin resistance are strongly correlated with the risk of developing NAFLD/NASH. Gut dysbiosis has also been associated with NAFLD/NASH progression in normal-weight individuals. More investigation is required to elucidate the mechanisms leading to NAFLD in normal-weight individuals.

Metabolic dysfunction and nonalcoholic fatty liver disease risk in individuals with a normal body mass index

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity, but is also common in individuals with a normal body mass index (BMI), who also experience the hepatic inflammation, fibrosis, and decompensated cirrhosis associated with NAFLD progression. The clinical evaluation and treatment of NAFLD in this patient population are challenging for the gastroenterologist. A better understanding of the epidemiology, natural history, and outcomes of NAFLD in individuals with normal BMI is emerging. This review examines the relationship between metabolic dysfunction and clinical characteristics associated with NAFLD in normal-weight individuals.

RECENT FINDINGS

Despite a more favorable metabolic profile, normal-weight NAFLD patients exhibit metabolic dysfunction. Visceral adiposity may be a critical risk factor for NAFLD in normal-weight individuals, and waist circumference may be better than BMI for assessing metabolic risk in these patients. Although screening for NAFLD is not presently recommended, recent guidelines may assist clinicians in the diagnosis, staging, and management of NAFLD in individuals with a normal BMI.

SUMMARY

Individuals with a normal BMI likely develop NAFLD as a result of different etiologies. Subclinical metabolic dysfunction may be a key component of NAFLD in these patients, and efforts to better understand this relationship in this patient population are needed.

Discovery of the First-in-Class Intestinal Restricted FXR and FABP1 Dual Modulator ZLY28 for the Treatment of Nonalcoholic Fatty Liver Disease

The prevalence of nonalcoholic steatohepatitis (NASH) is increasing rapidly worldwide, and NASH has become a serious problem for human health. Recently, the selective activation of the intestinal farnesoid X receptor (FXR) was considered as a more promising strategy for the treatment of NASH with lesser side effects due to reduced systemic exposure. Moreover, the inhibition of intestinal fatty acid binding protein 1 (FABP1) alleviated obesity and NASH by reducing dietary fatty acid uptake. In this study, the first-in-class intestinal restricted FXR and FABP1 dual-target modulator ZLY28 was discovered by comprehensive multiparameter optimization studies. The reduced systemic exposure of ZLY28 might provide better safety by decreasing the on- and off-target side effects in vivo. In NASH mice, ZLY28 exerted robust anti-NASH effects by inhibiting FABP1 and activating the FXR-FGF15 signaling pathway in the ileum. With the above attractive efficacy and preliminary safety profiles, ZLY28 is worthy of further evaluation as a novel anti-NASH agent.

Comparison of MAFLD and NAFLD Characteristics in Children

Background & aims: An international panel proposed a diagnostic framework for metabolic-associated fatty liver disease (MAFLD) in children. The aim was to compare the clinical features of MAFLD and nonalcoholic fatty liver disease (NAFLD) in children. Methods: The characteristic differences between NAFLD and MAFLD in children were compared with the National Health and Nutrition Examination Survey (NHANES) 2017–2018 in the U.S. and the Comprehensive Prevention Project for Overweight and Obese Adolescents (CPOOA) study in China. Results: In NHANES 2017–2018, regardless of which criteria were implemented, participants with hepatic steatosis were more likely to have higher BMI z-scores, a higher prevalence of hypertension or higher metabolic indices and higher non-invasive liver fibrosis scores (all p < 0.05). The cases diagnosed by those two definitions had a similarity of over 75%. More obese children were diagnosed with MAFLD than NAFLD (p < 0.001). However, approximately 19% of children with NAFLD present with normal weight and fasting glucose levels and cannot be diagnosed with MAFLD. The CPOOA study excluded viral infected liver disease and certain kinds of congenital causes of liver steatosis patients, resulting in children with NAFLD being identical with MAFLD children. Conclusions: Most clinical features were similar between children with MAFLD and children with NAFLD, and more than 75% of children with NAFLD can also be diagnosed with MAFLD. However, approximately 19% of children with NAFLD cannot be categorized as MAFLD. Therefore, to gain greater benefits from renaming NAFLD to MAFLD in pediatrics, the prevalence of different causes of hepatic steatosis in children needs to be understood.

Lean or diabetic subtypes predict increased all-cause and disease-specific mortality in metabolic-associated fatty liver disease

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) encompasses diverse disease groups with potentially heterogeneous clinical outcomes. We investigated the risk of all-cause and disease-specific mortality in MAFLD subgroups.

METHODS

Using the Korean National Health Insurance Service database, participants were divided into four subgroups: no MAFLD, MAFLD-diabetes, MAFLD-overweight/obese, and MAFLD-lean. Hazard ratios (HRs) and 95% confidence interval (CI) values for all-cause and disease-specific mortality according to MAFLD subgroups were analyzed using Cox proportional hazards models.

RESULTS

Among 9,935,314 participants, those with MAFLD-diabetes showed the highest risk of all-cause and disease-specific mortality. The HRs (95% CI) for all-cause mortality were 1.61 (1.59-1.63), 1.36 (1.34-1.38), and 1.19 (1.18-1.20) in the MAFLD-diabetes, MAFLD-lean, and MAFLD-overweight/obese groups, respectively. The magnitude of cardiovascular disease and cancer-related risk showed the same pattern. The risk of liver-related mortality in the MAFLD-lean group (HR: 2.84, 95% CI: 2.72-2.97) was comparable with that in the MAFLD-diabetes group (HR: 2.85, 95% CI: 2.75-2.95). When stratified by body mass index, liver-related mortality was the highest in MAFLD-lean individuals in the underweight group (HR, 5.03, 95% CI: 4.23-5.97).

CONCLUSIONS

The MAFLD-lean and MAFLD-diabetes groups had a higher risk of all-cause and disease-specific mortality than did the MAFLD-overweight/obese group. Classifying MAFLD subgroups based on metabolic phenotypes might help risk stratification of patients with MAFLD.

Current Knowledge on the Pathophysiology of Lean/Normal-Weight Type 2 Diabetes

Since early times, being overweight and obesity have been associated with impaired glucose metabolism and type 2 diabetes (T2D). Similarly, a less frequent adult-onset diabetes in low body mass index (BMI) people has been known for many decades. This form is mainly found in developing countries, whereby the largest increase in diabetes incidence is expected in coming years. The number of non-obese patients with T2D is also on the rise among non-white ethnic minorities living in high-income Western countries due to growing migratory flows. A great deal of energy has been spent on understanding the mechanisms that bind obesity to T2D. Conversely, the pathophysiologic features and factors driving the risk of T2D development in non-obese people are still much debated. To reduce the global burden of diabetes, we need to understand why not all obese people develop T2D and not all those with T2D are obese. Moreover, through both an effective prevention and the implementation of an individualized clinical management in all people with diabetes, it is hoped that this will help to reduce this global burden. The purpose of this review is to take stock of current knowledge about the pathophysiology of diabetes not associated to obesity and to highlight which aspects are worthy of future studies.

Utility of Human Relevant Preclinical Animal Models in Navigating NAFLD to MAFLD Paradigm

Fatty liver disease is an emerging contributor to disease burden worldwide. The past decades of work established the heterogeneous nature of non-alcoholic fatty liver disease (NAFLD) etiology and systemic contributions to the pathogenesis of the disease. This called for the proposal of a redefinition in 2020 to that of metabolic dysfunction-associated fatty liver disease (MAFLD) to better reflect the current understanding of the disease. To date, several clinical cohort studies comparing NAFLD and MAFLD hint at the relevancy of the new nomenclature in enriching for patients with more severe hepatic injury and extrahepatic comorbidities. However, the underlying systemic pathogenesis is still not fully understood. Preclinical animal models have been imperative in elucidating key biological mechanisms in various contexts, including intrahepatic disease progression, interorgan crosstalk and systemic dysregulation. Furthermore, they are integral in developing novel therapeutics against MAFLD. However, substantial contextual variabilities exist across different models due to the lack of standardization in several aspects. As such, it is crucial to understand the strengths and weaknesses of existing models to better align them to the human condition. In this review, we consolidate the implications arising from the change in nomenclature and summarize MAFLD pathogenesis. Subsequently, we provide an updated evaluation of existing MAFLD preclinical models in alignment with the new definitions and perspectives to improve their translational relevance.

Nonalcoholic fatty liver disease in relation to the remission and progression along the glycemic continuum

BACKGROUND

The study aimed to explore the associations of nonalcoholic fatty liver disease (NAFLD) with the remission and progression along the glycemic continuum.

METHODS

This prospective cohort study was performed among the general population in 2010-2015. NAFLD was defined as ultrasound-detected hepatic steatosis with absence of excessive alcohol consumption and other hepatic diseases. Remission of type 2 diabetes referred to glycated hemoglobin <6.5% without hypoglycemic agents for ≥3 months. Prediabetes remission referred to normalization of blood glucose. Multivariable logistic analysis was applied to identify the risk of glycemic metabolic transition.

RESULTS

During a median follow-up of 4.3 years, participants with NAFLD had a significantly higher risk of progressing from normal glucose tolerance to diabetes (3.36 [1.60-7.07]) and lower likelihood of diabetes remission (0.48 [0.30-0.78]). Associations in participants with overweight or obesity and higher probability of hepatic fibrosis remained consistent. Results related to the effect of NAFLD on the specific glucose parameters were generally in line with the changes of glycemic status. NAFLD improvement decreased the risk of prediabetes progressing to diabetes (0.50 [0.32-0.80]) and increased the probability of prediabetes remission (2.67 [1.49-4.79]). NAFLD tended to show the most significant association with glycemic progression and decreased the likelihood in remission of prediabetes and diabetes.

CONCLUSIONS

Presence of NAFLD increased risk of glycemic progression and decreased likelihood of remission. NAFLD improvement mitigated glycemic deterioration, whereas NAFLD progression impeded the chance of remission. The results emphasized joint management of NAFLD and diabetes and further focused on liver-specific subgroups of diabetes to tailor early intervention.