Insulin resistance drives hepatic de novo lipogenesis in nonalcoholic fatty liver disease

Hepatic glucokinase regulatory protein and carbohydrate response element binding protein attenuation reduce de novo lipogenesis but do not mitigate intrahepatic triglyceride accumulation in Aldob deficiency

OBJECTIVE

Stable isotope studies have shown that hepatic de novo lipogenesis (DNL) plays an important role in the pathogenesis of intrahepatic lipid (IHL) deposition. Furthermore, previous research has demonstrated that fructose 1-phosphate (F1P) not only serves as a substrate for DNL, but also acts as a signalling metabolite that stimulates DNL from glucose. The aim of this study was to elucidate the mediators of F1P-stimulated DNL, with special focus on two key regulators of intrahepatic glucose metabolism, i.e., glucokinase regulatory protein (GKRP) and carbohydrate response element binding protein (ChREBP).

METHODS

Aldolase B deficient mice (Aldob-/-), characterized by hepatocellular F1P accumulation, enhanced DNL, and hepatic steatosis, were either crossed with GKRP deficient mice (Gckr-/-) or treated with short hairpin RNAs directed against hepatic ChREBP.

RESULTS

Aldob-/- mice showed higher rates of de novo palmitate synthesis from glucose when compared to wildtype mice (p < 0.001). Gckr knockout reduced de novo palmitate synthesis in Aldob-/- mice (p = 0.017), without affecting the hepatic mRNA expression of enzymes involved in DNL. In contrast, hepatic ChREBP knockdown normalized the hepatic mRNA expression levels of enzymes involved in DNL and reduced fractional DNL in Aldob-/- mice (p < 0.05). Of interest, despite downregulation of DNL in response to Gckr and ChREBP attenuation, no reduction in intrahepatic triglyceride levels was observed.

CONCLUSIONS

Both GKRP and ChREBP mediate F1P-stimulated DNL in aldolase B deficient mice. Further studies are needed to unravel the role of GKRP and hepatic ChREBP in regulating IHL accumulation in aldolase B deficiency.

Greater hepatic lipid saturation is associated with impaired glycaemic regulation in men with metabolic dysfunction-associated steatotic liver disease but is not altered by 6 weeks of exercise training

AIMS

To examine the impact of impaired glycaemic regulation (IGR) and exercise training on hepatic lipid composition in men with metabolic dysfunction-associated steatotic liver disease (MASLD).

MATERIALS AND METHODS

In Part A (cross-sectional design), 40 men with MASLD (liver proton density fat fraction [PDFF] ≥5.56%) were recruited to one of two groups: (1) normal glycaemic regulation (NGR) group (glycated haemoglobin [HbA1c] < 42 mmol∙mol-1 [<6.0%]; n = 14) or (2) IGR group (HbA1c ≥ 42 mmol∙mol-1 [≥6.0%]; n = 26). In Part B (randomized controlled trial design), participants in the IGR group were randomized to one of two 6-week interventions: (1) exercise training (EX; 70%-75% maximum heart rate; four sessions/week; n = 13) or (2) non-exercise control (CON; n = 13). Saturated (SI; primary outcome), unsaturated (UI) and polyunsaturated (PUI) hepatic lipid indices were determined using proton magnetic resonance spectroscopy. Additional secondary outcomes included liver PDFF, HbA1c, fasting plasma glucose (FPG), homeostatic model assessment of insulin resistance (HOMA-IR), peak oxygen uptake (VO2 peak), and plasma cytokeratin-18 (CK18) M65, among others.

RESULTS

In Part A, hepatic SI was higher and hepatic UI was lower in the IGR versus the NGR group (p = 0.038), and this hepatic lipid profile was associated with higher HbA1c levels, FPG levels, HOMA-IR and plasma CK18 M65 levels (rs ≥0.320). In Part B, hepatic lipid composition and liver PDFF were unchanged after EX versus CON (p ≥ 0.257), while FPG was reduced and VO2 peak was increased (p ≤ 0.030). ΔVO2 peak was inversely associated with Δhepatic SI (r = -0.433) and positively associated with Δhepatic UI and Δhepatic PUI (r ≥ 0.433).

CONCLUSIONS

Impaired glycaemic regulation in MASLD is characterized by greater hepatic lipid saturation; however, this composition is not altered by 6 weeks of moderate-intensity exercise training.

Elevations in plasma glucagon are associated with reduced insulin clearance after ingestion of a mixed-macronutrient meal in people with and without type 2 diabetes

AIMS/HYPOTHESIS

The temporal suppression of insulin clearance after glucose ingestion is a key determinant of glucose tolerance for people without type 2 diabetes. Whether similar adaptations are observed after the ingestion of a mixed-macronutrient meal is unclear.

METHODS

In a secondary analysis of data derived from two randomised, controlled trials, we studied the temporal responses of insulin clearance after the ingestion of a standardised breakfast meal consisting of cereal and milk in lean normoglycaemic individuals (n=12; Lean-NGT), normoglycaemic individuals with central obesity (n=11; Obese-NGT) and in people with type 2 diabetes (n=19). Pre-hepatic insulin secretion rates were determined by the deconvolution of C-peptide, and insulin clearance was calculated using a single-pool model. Insulin sensitivity was measured by an oral minimal model.

RESULTS

There were divergent time course changes in insulin clearance between groups. In the Lean-NGT group, there was an immediate post-meal increase in insulin clearance compared with pre-meal values (p<0.05), whereas insulin clearance remained stable at baseline values in Obese-NGT or declined slightly in the type 2 diabetes group (p<0.05). The mean AUC for insulin clearance during the test was ~40% lower in the Obese-NGT (1.3 ± 0.4 l min-1 m-2) and type 2 diabetes (1.4 ± 0.7 l min-1 m-2) groups compared with Lean-NGT (1.9 ± 0.5 l min-1 m-2; p<0.01), with no difference between the Obese-NGT and type 2 diabetes groups. HOMA-IR and glucagon AUC emerged as predictors of insulin clearance AUC, independent of BMI, age or insulin sensitivity (adjusted R2=0.670). Individuals with increased glucagon AUC had a 40% reduction in insulin clearance AUC (~ -0.75 l min-1 m-2; p<0.001).

CONCLUSIONS/INTERPRETATION

The ingestion of a mixed-macronutrient meal augments differing temporal profiles in insulin clearance among individuals without type 2 diabetes, which is associated with HOMA-IR and the secretion of glucagon. Further research investigating the role of hepatic glucagon signalling in postprandial insulin kinetics is warranted.

TRIAL REGISTRATION

ISRCTN17563146 and ISRCTN95281775.

Interleaved trinuclear MRS for single-session investigation of carbohydrate and lipid metabolism in human liver at 7T

The liver plays a central role in metabolic homeostasis, as exemplified by a variety of clinical disorders with hepatic and systemic metabolic disarrays. Of particular interest are the complex interactions between lipid and carbohydrate metabolism in highly prevalent conditions such as obesity, diabetes, and fatty liver disease. Limited accessibility and the need for invasive procedures challenge direct investigations in humans. Hence, noninvasive dynamic evaluations of glycolytic flux and steady-state assessments of lipid levels and composition are crucial for basic understanding and may open new avenues toward novel therapeutic targets. Here, three different MR spectroscopy (MRS) techniques that have been combined in a single interleaved examination in a 7T MR scanner are evaluated. 1H-MRS and 13C-MRS probe endogenous metabolites, while deuterium metabolic imaging (DMI) relies on administration of deuterated tracers, currently 2H-labelled glucose, to map the spatial and temporal evolution of their metabolic fate. All three techniques have been optimized for a robust single-session clinical investigation and applied in a preliminary study of healthy subjects. The use of a triple-channel 1H/2H/13C RF coil enables interleaved examinations with no need for repositioning. Short-echo-time STEAM spectroscopy provides well resolved spectra to quantify lipid content and composition. The relative benefits of using water saturation versus metabolite cycling and types of respiratory synchronization were evaluated. 2H-MR spectroscopic imaging allowed for registration of time- and space-resolved glucose levels following oral ingestion of 2H-glucose, while natural abundance 13C-MRS of glycogen provides a dynamic measure of hepatic glucose storage. For DMI and 13C-MRS, the measurement precision of the method was estimated to be about 0.2 and about 16 mM, respectively, for 5 min scanning periods. Excellent results were shown for the determination of dynamic uptake of glucose with DMI and lipid profiles with 1H-MRS, while the determination of changes in glycogen levels by 13C-MRS is also feasible but somewhat more limited by signal-to-noise ratio.

Association between hemoglobin and non-alcoholic fatty liver disease (NAFLD) in United States adults: Results from NHANES 2017-2020

Background

Non-alcoholic fatty liver disease (NAFLD), a chronic liver condition of increasing prevalence, is closely related to various metabolic disorders. Hemoglobin, a protein that transports oxygen in red blood cells, is the focus of this study, which seeks to investigate its potential association with NAFLD.

Methods

We selected 6,516 eligible adult participants from the United States using the 2017-2020 National Health and Nutrition Examination Survey database for cross-sectional analyses. We analyzed the association of hemoglobin with NAFLD using weighted logistic regression models.

Results

The study performed a weighted logistic regression modeling analysis, which verified that hemoglobin levels were positively associated with NAFLD, especially in the higher hemoglobin quartile groups. Subgroup analyses revealed no significant interactions, demonstrating the robustness of the model. The analysis of mediation effects showed that Gamma-Glutamyl Transferase, Alanine Aminotransferase, and triglycerides were important mediating variables in the relationship between hemoglobin and NAFLD.

Conclusion

Increased hemoglobin levels were found to be significantly and independently associated with an increased NAFLD risk. This insight is crucial for the risk assessment and early detection of NAFLD, underscoring the need for heightened vigilance in individuals with higher hemoglobin levels.

Are all sugars equal? Role of the food source in physiological responses to sugars with an emphasis on fruit and fruit juice

High (free) sugar intakes can increase self-reported energy intake and are associated with unfavourable cardiometabolic health. However, sugar source may modulate the effects of sugars due to several mechanisms including the food matrix. The aim of this review was to assess the current state of evidence in relation to food source effects on the physiological responses to dietary sugars in humans relevant to cardiometabolic health. An additional aim was to review potential mechanisms by which food sources may influence such responses. Evidence from meta-analyses of controlled intervention trials was used to establish the balance of evidence relating to the addition of sugars to the diet from sugar-sweetened beverages, fruit juice, honey and whole fruit on cardiometabolic outcomes. Subsequently, studies which have directly compared whole fruit with fruit juices, or variants of fruit juices, were discussed. In summary, the sources of sugars can impact physiological responses, with differences in glycaemic control, blood pressure, inflammation, and acute appetite. Longer-term effects and mechanisms require further work, but initial evidence implicates physical structure, energy density, fibre, potassium and polyphenol content, as explanations for some of the observed responses.

Obesity and MASLD: Is weight loss the (only) key to treat metabolic liver disease?

Metabolic dysfunction-associated steatotic liver disease (MASLD) closely associates with obesity and type 2 diabetes. Lifestyle intervention and bariatric surgery aiming at substantial weight loss are cornerstones of MASLD treatment by improving histological outcomes and reducing risks of comorbidities. Originally developed as antihyperglycemic drugs, incretin (co-)agonists and SGLT2 inhibitors also reduce steatosis and cardiorenovascular events. Certain incretin agonists effectively improve histological features of MASLD, but not fibrosis. Of note, beneficial effects on MASLD may not necessarily require weight loss. Despite moderate weight gain, one PPARγ agonist improved adipose tissue and MASLD with certain benefit on fibrosis in post-hoc analyses. Likewise, the first THRβ-agonist was recently provisionally approved because of significant improvements of MASLD and fibrosis. We here discuss liver-related and metabolic effects induced by different MASLD treatments and their association with weight loss. Therefore, we compare results from clinical trials on drugs acting via weight loss (incretin (co)agonists, SGLT2 inhibitors) with those exerting no weight loss (pioglitazone; resmetirom). Furthermore, other drugs in development directly targeting hepatic lipid metabolism (lipogenesis inhibitors, FGF21 analogs) are addressed. Although THRβ-agonism may effectively improve hepatic outcomes, MASLD treatment concepts should consider all cardiometabolic risk factors for effective reduction of morbidity and mortality in the affected people.

Regulation of hepatic lipogenesis by asymmetric arginine methylation

BACKGROUND AND AIMS

Hepatic lipogenesis is elevated in nutrient abundant conditions to convert the excess carbohydrate into triacylglycerol (TAG). Fatty acyl moiety of TAG is eventually transported into adipose tissues by very low density lipoprotein, leading to the accumulation of TAG as a preferred storage form of excess energy. Disruption of the balance between TAG clearance and synthesis leads to the accumulation of lipids in the liver, leading to the progression of non-alcoholic fatty liver disease (NAFLD) including non-alcoholic steatohepatitis. Protein arginine methyltransferase (PRMT) 6 has been linked to the various metabolic processes including hepatic gluconeogenesis, muscle atrophy and lipodystrophy in mouse models. However, the role of PRMT6 in the control of hepatic lipogenesis has not been elucidated to date.

METHODS

We assessed the interaction between PRMT6 and LXR alpha by using co-immunoprecipitation assay. The specific arginine residue of LXR alpha that is methylated by PRMT6 was assessed by LC-MS/MS assay and the functional consequences of LXR alpha methylation was explored by mSREBP-1c luciferase assay. The effect of PRMT6 on hepatic lipogenesis was assessed by adenovirus-mediated ectopic expression of PRMT6 or knockdown of PRMT6 via shRNA in hepatocytes. Finally, the role of PRMT6 in hepatic lipid metabolism in vivo was explored by either ectopic expression of LXR alpha mutant that is defective in PRMT6-mediated arginine methylation or knockdown of PRMT6 in liver.

RESULTS

We found that promoter activity of sterol regulatory element binding protein (SREBP) 1c is robustly activated by PRMT6. Interestingly, we demonstrated that PRMT6 binds to LXR alpha, a transcription factor for SREBP-1c, via its LXXLL motif, leading to the asymmetric dimethylation of an arginine residue and activation of this protein. Indeed, ectopic expression of PRMT6 in hepatocytes led to the enhanced expression of LXR alpha target genes in the lipogenic pathway. Conversely, genetic or pharmacological inhibition of PRMT6 diminished expression of lipogenic genes and the lipid accumulation in primary hepatocytes. Mechanistically, we found that asymmetric dimethylation of LXR alpha led to the dissociation of small heterodimer partner (SHP), a transcriptional co-inhibitor of this factor, resulting in the activation of LXR alpha-mediated transcriptional process. Finally, we showed that disruption of asymmetric dimethylation of LXR alpha in the liver led to the diminished expression of genes in the lipogenesis, resulting in the reduced hepatic lipid accumulation in high fat diet-fed mice in vivo.

CONCLUSIONS

We showed that PRMT6 modulates LXR alpha activity by conferring asymmetric dimethylation of arginine 253, thus blocking SHP-mediated inhibition and promoting hepatic lipid accumulation. These results suggest that PRMT6 is critical in the control of lipid homeostasis by regulation of LXR alpha-mediated lipogenesis in the liver.

Are dietary factors associated with cardiometabolic risk factors in patients with non-alcoholic fatty liver disease?

Background

Non-alcoholic fatty liver disease (NAFLD) is intricately linked with dietary patterns and metabolic homeostasis. Therefore, the present study focused to investigate the relation between dietary patterns and cardiometabolic risk factors related to fatty liver in NAFLD patients.

Methods

This cross-sectional study included 117 individuals whose body mass index (BMI) threshold of 25 or above diagnosed with NAFLD by magnetic resonance imaging. The hospital database was used to review the patients' medical records such as lipid parameters, and fasting blood sugar. Anthropometric measurements and body composition were measured by researchers. Likewise, data from 24-h dietary recalls of individuals were collected to analyze their energy and nutrient intakes besides calculating dietary insulin index (DII), dietary insulin load (DIL), dietary glycemic index (DGI), and dietary glycemic load (DGL).

Results

Participants consuming diets with distinct levels of DII, DIL, DGI, and DGL exhibited variations in dietary energy and nutrient intake. Specifically, differences were noted in carbohydrate intake across quartiles of DII, DIL, DGI, and DGL, while fructose consumption showed variability in DGL quartiles (p ≤ 0.05). Moreover, sucrose intake demonstrated distinctions in both DII and DGL quartiles (p ≤ 0.05). No statistical difference was found in biochemical parameters and the fatty liver index among different levels of DII, DIL, DGI, and DGL (p > 0.05). After adjusting for potential confounders, participants with a higher DGI had four times greater odds of developing metabolic syndrome compared to those in the bottom quartile (OR, 4.32; 95% CI [1.42-13.11]).

Conclusion

This study provides initial evidence of the intricate association between dietary factors and NAFLD, emphasizing the necessity for further research including prospective designs with larger sample sizes, to garner additional insights.

Diabetes mellitus-Progress and opportunities in the evolving epidemic

Diabetes, a complex multisystem metabolic disorder characterized by hyperglycemia, leads to complications that reduce quality of life and increase mortality. Diabetes pathophysiology includes dysfunction of beta cells, adipose tissue, skeletal muscle, and liver. Type 1 diabetes (T1D) results from immune-mediated beta cell destruction. The more prevalent type 2 diabetes (T2D) is a heterogeneous disorder characterized by varying degrees of beta cell dysfunction in concert with insulin resistance. The strong association between obesity and T2D involves pathways regulated by the central nervous system governing food intake and energy expenditure, integrating inputs from peripheral organs and the environment. The risk of developing diabetes or its complications represents interactions between genetic susceptibility and environmental factors, including the availability of nutritious food and other social determinants of health. This perspective reviews recent advances in understanding the pathophysiology and treatment of diabetes and its complications, which could alter the course of this prevalent disorder.

Improving insulin resistance by sulforaphane via activating the Bacteroides and Lactobacillus SCFAs-GPR-GLP1 signal axis

Background: Insulin resistance (IR) is closely associated with non-alcoholic fatty liver disease (NAFLD), and the gut microbiome contributes to the development of NAFLD. Sulforaphane (SFN) is a phytochemical in cruciferous vegetables that could improve lipid metabolism disorder. However, whether SFN can alleviate IR in NAFLD by regulating the intestinal flora remains unclear. Methods: SFN was administered to high fat diet (HFD)-fed Wistar rats for 10 weeks. Gut microbiota was analysed by 16S rRNA sequencing and the short chain fatty acids (SCFAs) by gas chromatography. The expression of tight junction protein and the numbers of Lactobacillus, Bacteroides and Bifidobacterium were determined by qPCR. The expression of G-protein-coupled receptor 41/43 (GPR41/43) was determined by western blot. A randomized controlled trial (RCT) was conducted in NAFLD patients with broccoli seed tablets (rich in SFN, 42 mg d-1) as intervention for 12 weeks. Thirty-six volunteers with abnormal glucose before the broccoli seed tablet treatment were selected in the intervention group to analyze their blood glucose, insulin, homeostasis model assessment-insulin resistance index (HOMA-IRI), homeostasis model assessment-insulin sensitivity index (HOMA-ISI) and glucagon-like peptide (GLP-1). Results: SFN reduced blood glucose and HOMA-IRI while increasing insulin sensitivity in HFD rats. SFN reduced glycogen synthase kinase 3 (GSK-3), phosphoenolpyruvate carboxykinase (PEPCK) activity, and phosphorylation of serine residues of IRS-2 induced by HFD. SFN reshaped the gut microbiota composition of HFD-induced rats and, especially, increased the content of Bacteroidaceae, Lactobacillaceae and Bifidobacteriaceae, which are related to the improvement from SFN of the blood glucose and HOMA-IRI. The increased numbers of Bacteroides and Lactobacillus were the targets of SFN to enhance the expression of tight junction proteins ZO-1 and occludin, thereby lowering lipopolysaccharide content to reduce inflammation, ultimately alleviating IR. Bacteroides and Lactobacillus produced SCFAs, which activated GPR41/43 to secrete GLP1. Moreover, it was also confirmed in RCT that SFN intervention increased the level of GLP1 in NAFLD patients, which was positively correlated with the reduction of blood glucose and HOMA-IR. Conclusions: SFN alleviated IR in NAFLD via the Bacteroides and Lactobacillus SCFAs-GPR41/43-GLP1 axis and protected the intestinal mucosal barrier to decrease inflammation.

Zinc finger BED-type containing 3 promotes hepatic steatosis by interacting with polypyrimidine tract-binding protein 1

AIMS/HYPOTHESIS

The relationship between metabolic dysfunction-associated steatotic liver disease (MASLD) and type 2 diabetes mellitus, insulin resistance and the metabolic syndrome is well established. While zinc finger BED-type containing 3 (ZBED3) has been linked to type 2 diabetes mellitus and the metabolic syndrome, its role in MASLD remains unclear. In this study, we aimed to investigate the function of ZBED3 in the context of MASLD.

METHODS

Expression levels of ZBED3 were assessed in individuals with MASLD, as well as in cellular and animal models of MASLD. In vitro and in vivo analyses were conducted using a cellular model of MASLD induced by NEFA and an animal model of MASLD induced by a high-fat diet (HFD), respectively, to investigate the role of ZBED3 in MASLD. ZBED3 expression was increased by lentiviral infection or tail-vein injection of adeno-associated virus. RNA-seq and bioinformatics analysis were employed to examine the pathways through which ZBED3 modulates lipid accumulation. Findings from these next-generation transcriptome sequencing studies indicated that ZBED3 controls SREBP1c (also known as SREBF1; a gene involved in fatty acid de novo synthesis); thus, co-immunoprecipitation and LC-MS/MS were utilised to investigate the molecular mechanisms by which ZBED3 regulates the sterol regulatory element binding protein 1c (SREBP1c).

RESULTS

In this study, we found that ZBED3 was significantly upregulated in the liver of individuals with MASLD and in MASLD animal models. ZBED3 overexpression promoted NEFA-induced triglyceride accumulation in hepatocytes in vitro. Furthermore, the hepatocyte-specific overexpression of Zbed3 promoted hepatic steatosis. Conversely, the hepatocyte-specific knockout of Zbed3 resulted in resistance of HFD-induced hepatic steatosis. Mechanistically, ZBED3 interacts directly with polypyrimidine tract-binding protein 1 (PTBP1) and affects its binding to the SREBP1c mRNA precursor to regulate SREBP1c mRNA stability and alternative splicing.

CONCLUSIONS/INTERPRETATION

This study indicates that ZBED3 promotes hepatic steatosis and serves as a critical regulator of the progression of MASLD.

DATA AVAILABILITY

RNA-seq data have been deposited in the NCBI Gene Expression Omnibus ( www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE231875 ). MS proteomics data have been deposited to the ProteomeXchange Consortium via the iProX partner repository ( https://proteomecentral.proteomexchange.org/cgi/GetDataset?ID=PXD041743 ).

Understanding the cause of type 2 diabetes

Type 2 diabetes has long been thought to have heterogenous causes, even though epidemiological studies uniformly show a tight relationship with overnutrition. The twin cycle hypothesis postulated that interaction of self-reinforcing cycles of fat accumulation inside the liver and pancreas, driven by modest but chronic positive calorie balance, could explain the development of type 2 diabetes. This hypothesis predicted that substantial weight loss would bring about a return to the non-diabetic state, permitting observation of the pathophysiology determining the transition. These changes were postulated to reflect the basic mechanisms of causation in reverse. A series of studies over the past 15 years has elucidated these underlying mechanisms. Together with other research, the interaction of environmental and genetic factors has been clarified. This knowledge has led to successful implementation of a national programme for remission of type 2 diabetes. This Review discusses the paucity of evidence for heterogeneity in causes of type 2 diabetes and summarises the in vivo pathophysiological changes, which cause this disease of overnutrition. Type 2 diabetes has a homogenous cause expressed in genetically heterogenous individuals.

Diet/photoperiod mediated changes in cerebellar clock genes causes locomotor shifts and imperative changes in BDNF-TrkB pathway

Neuropsychological studies report anxiety and depression like symptoms in patients suffering from lifestyle disorder but its impact on locomotor function lacks clarity. Our study investigates locomotor deficits resulting due to perturbations in cerebellum of high fat diet (HFD), chronodisruption (CD) or a combination (HCD) model of lifestyle disorder. Significant downregulation in levels of cerebellar clock genes (Bmal-1, Clock, Per 1 and Per 2) and Bdnf-Trkb pathway genes (Bdnf, TrkB and Syn1 levels) were recorded. Further, locomotor deficits were observed in all the three experimental groups as evidenced by actimeter test, pole test and wire hanging test. Nuclear pyknosis of Purkinje cells, their derangement and inflammation were the hallmark of cerebellar tissue of all the three experimental groups. Taken together, this study generates important links between cerebellar clock oscillations, locomotor function and Bdnf-TrkB signaling.

The correlation between hepatic controlled attenuation parameter (CAP) value and insulin resistance (IR) was stronger than that between body mass index, visceral fat area and IR

BACKGROUND

Hepatic controlled attenuation parameter (CAP) is a novel marker for quantifying hepatic fat accumulation. Insulin resistance (IR) plays a major role in the pathogenesis and natural history of hepatic steatosis. This study aimed to investigate the possible relationship between CAP value and IR.

METHODS

This study included a total of 420 patients with overweight or obesity who came to the obesity clinic at Tianjin Union Medical Center. Vibration-controlled transient elastography examination was conducted to detect CAP and liver stiffness measurement (LSM) values. Body composition, including visceral fat area (VFA), and body fat mass (BFM), was evaluated by the direct segmental multi-frequency bioelectrical impedance analysis (BIA). The associations between CAP value, body mass index (BMI), VFA, BFM and homeostasis model assessment of insulin resistance (HOMA-IR) were analyzed.

RESULTS

CAP value was positively associated with HOMA-IR (r = 0.568, P < 0.001), the strength of which was much stronger than BMI, VFA, and BFM. In multivariate linear regression, CAP value and HOMA-IR showed a significant positive association (adjusted β = 0.015, 95% CI 0.007-0.022, P < 0.001). Subgroup analysis suggested no significant interaction between CAP value and HOMA-IR across age, BMI, LSM, hypertension, and sex groups (all P for interaction > 0.05).

CONCLUSIONS

Hepatic CAP value is more remarkably than other obesity markers associated with HOMA-IR in individuals with overweight or obesity, regardless of age, BMI, LSM, hypertension, and sex.

Triglyceride glucose index as a predictor for non-alcoholic fatty liver disease: insights from a longitudinal analysis in non-obese individuals

Background

A substantial portion of non-obese population is afflicted with Non-alcoholic Fatty Liver Disease (NAFLD). The Triglyceride Glucose (TyG) index, a quantifier of insulin resistance magnitude, is determined by the product of fasting plasma glucose and triglyceride concentrations. The relationship between the TyG index and NAFLD within this cohort remains ambiguous.

Methods

We conducted a retrospective analysis utilizing datasets acquired from the Dryad digital repository. Non-obese participants (BMI < 25 kg/m2) were enrolled at the Wenzhou Medical Center of Wenzhou People's Hospital between January 2010 and December 2014. Demographic information and biochemical parameters were systematically compiled, and the diagnosis of NAFLD was established through ultrasonographic evidence.

Results

This study cohort included 16,172 non-obese participants with a 5-year follow-up, among whom 2,322 (14.36%) developed NAFLD. The disparity between TyG index quartiles in the accumulative incidence of new-onset NAFLD was distinct, with an increasing risk of new-onset NAFLD as the TyG index increased. Participants in highest quartile exhibited the maximum risk of NAFLD. In the fully adjusted model 3, the hazard ratios for NAFLD in Q2, Q3, and Q4 were 2.15 (1.62, 2.87), 2.89 (2.20, 3.80) and 4.58 (3.48, 6.02), respectively. Meanwhile, the TyG index and NAFLD risk showed a highly significant overall correlation (p < 0.0001) and nonlinearity (p < 0.0001) according to the limited cubic splines. In subgroup analysis, a significant interaction was noted between new-onset NAFLD and SBP (<140 mmHg vs. ≥140 mmHg; P for interaction = 0.0114). The SBP < 140 mmHg subgroup demonstrated an enhanced TyG index influence on NAFLD risk (HR = 2.83, 95% CI: 2.48-3.23, p < 0.0001).

Conclusion

The TyG index serves as a straightforward instrument for assessing NAFLD risk in non-obese individuals, enabling prompt identification and management in this population segment.

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

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

Hepatic fatty acid and glucose handling in metabolic disease: Potential impact on cardiovascular disease risk

The prevalence of metabolic diseases, including type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing. Although invariably associated with obesity, the importance of fat deposition in non-adipose tissue organs has yet to be fully explored. Pathological ectopic fat deposition within the liver (known as (MASLD)) has been suggested to underlie the development of T2DM and is now emerging as an independent risk factor for cardiovascular disease (CVD). The process of hepatic de novo lipogenesis (DNL), that is the synthesis of fatty acids from non-lipid precursors (e.g. glucose), has received much attention as it sits at the intersect of hepatic glucose and fatty acid handling. An upregulation of the DNL pathway has been suggested to be central in the development of metabolic diseases (including MASLD, insulin resistance, and T2DM). Here we review the evidence to determine if hepatic DNL may play a role in the development of MASLD and T2DM and therefore underlie an increased risk of CVD.

7-Hydroxyflavone improves nonalcoholic fatty liver disease by acting on STK24

The escalating incidence of nonalcoholic fatty liver disease (NAFLD) is closely associated with a high-fat diet, leading to a decline in quality of life and significant health impairment. 7-Hydroxyflavone (7-HY) is a flavonoid known for its anti-inflammatory, anticarcinogenic, and antioxidant effects. This study aims to assess the ameliorative effects of 7-HY on NAFLD induced by a high-fat diet and elucidate underlying mechanisms. Oleic acid/palmitic acid-induced HepG2 cells and C57BL/6 mice on a high-fat diet were utilized as in vitro and in vivo models. In animal experiments, 7-HY was utilized as a dietary supplement. The 15-week in vivo experiment monitored body weight, body fat percentage, glucose tolerance, insulin tolerance, and metabolic indexes. Commercial kits assessed triglyceride (TG) and total cholesterol levels in cells, liver tissue, and blood. Discovery Studio identified potential targets of 7-HY, compared with NAFLD-associated targets in the GeneCards database. Results indicated 7-HY mitigated fat accumulation, hepatic steatosis, and oxidative stress induced by a high-fat diet. Furthermore, 7-HY showed potential efficacy in ameliorating abnormal glucose metabolism and promoting energy metabolism. Reverse target finding and molecular docking demonstrated a robust interaction between 7-HY and serine/threonine kinase 24 (STK24). Subsequent experimental results confirmed 7-HY's ability to inhibit TG deposition in HepG2 cells through interaction with STK24. In conclusion, 7-HY demonstrated the capacity to alleviate high-fat diet-induced NAFLD, presenting a novel strategy for the prevention and treatment of NAFLD.

Modification of lipoprotein metabolism and function driving atherogenesis in diabetes

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease, characterized by raised blood glucose levels and impaired lipid metabolism resulting from insulin resistance and relative insulin deficiency. In diabetes, the peculiar plasma lipoprotein phenotype, consisting in higher levels of apolipoprotein B-containing lipoproteins, hypertriglyceridemia, low levels of HDL cholesterol, elevated number of small, dense LDL, and increased non-HDL cholesterol, results from an increased synthesis and impaired clearance of triglyceride rich lipoproteins. This condition accelerates the development of the atherosclerotic cardiovascular disease (ASCVD), the most common cause of death in T2DM patients. Here, we review the alteration of structure, functions, and distribution of circulating lipoproteins and the pathophysiological mechanisms that induce these modifications in T2DM. The review analyzes the influence of diabetes-associated metabolic imbalances throughout the entire process of the atherosclerotic plaque formation, from lipoprotein synthesis to potential plaque destabilization. Addressing the different pathophysiological mechanisms, we suggest improved approaches for assessing the risk of adverse cardiovascular events and clinical strategies to reduce cardiovascular risk in T2DM and cardiometabolic diseases.

Curcumin supplementation alleviates hepatic fat content associated with modulation of gut microbiota-dependent bile acid metabolism in patients with nonalcoholic simple fatty liver disease: a randomized controlled trial

BACKGROUND

Our previous studies showed that curcumin prevented hepatic steatosis in animal models.

OBJECTIVES

This study aimed to assess the effects of curcumin on hepatic fat content, body composition, and gut microbiota-dependent bile acid (BA) metabolism in patients with nonalcoholic simple fatty liver (NASFL).

METHODS

In a 24-wk double-blind randomized trial, 80 patients with NASFL received 500 mg/d curcumin or placebo. Hepatic fat content was measured using FibroTouch-based controlled attenuation parameters (CAPs). Microbial composition and BA metabolites were analyzed using 16S rRNA sequencing and metabolomics.

RESULTS

Curcumin consumption significantly reduced CAP value compared with placebo (-17.5 dB/m; 95% confidence interval [CI]: -27.1, -7.8 dB/m; P < 0.001). This corresponded to reduction in weight (-2.6 kg; 95% CI: -4.4, -0.8 kg; P < 0.001) and BMI (-1.0 kg/m2; 95% CI: -2.0, -0.1 kg/m2; P = 0.032) compared with placebo group. Additionally, free fatty acid (-0.12 mmol/L; 95% CI: -0.20, -0.04 mmol/L; P = 0.004), triglycerides (-0.29 mmol/L; 95% CI: -0.41, -0.14 mmol/L; P < 0.001), fasting blood glucose (-0.06 mmol/L; 95% CI: -0.12, -0.01 mmol/L; P = 0.038), hemoglobin A1c (-0.06%; 95% CI: -0.33, -0.01%; P = 0.019), and insulin (-4.94 μU/L; 95% CI: -9.73, -0.15 μU/L; P = 0.043) showed significant reductions in the curcumin group compared with placebo group. Gut microbiota analysis indicated that curcumin significantly decreased Firmicutes to Bacteroidetes ratio and significantly increased Bacteroides abundance. Serum levels of deoxycholic acid, the most potent activator of Takeda G protein-coupled receptor 5 (TGR5), were significantly elevated after curcumin intervention (37.5 ng/mL; 95% CI: 6.7, 68.4 ng/mL; P = 0.018). Curcumin treatment also increased TGR5 expression in peripheral blood mononuclear cells and serum glucagon-like peptide-1 levels (0.73 ng/mL; 95% CI: 0.16, 1.30 ng/mL; P = 0.012).

CONCLUSIONS

Improvements in gut microbiota-dependent BA metabolism and TGR5 activation after 24-wk curcumin intervention were associated with a reduction in hepatic fat content in patients with NASFL, providing evidence that curcumin is a potential nutritional therapy for NASFL. The trial was registered at www.chictr.org.cn as ChiCTR2200058052.

Review article: Hepatic steatosis and its associations with acute and chronic liver diseases

BACKGROUND

Hepatic steatosis is a common finding in liver histopathology and the hallmark of metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), whose global prevalence is rising.

AIMS

To review the histopathology of hepatic steatosis and its mechanisms of development and to identify common and rare disease associations.

METHODS

We reviewed literature on the basic science of lipid droplet (LD) biology and clinical research on acute and chronic liver diseases associated with hepatic steatosis using the PubMed database.

RESULTS

A variety of genetic and environmental factors contribute to the development of chronic hepatic steatosis or steatotic liver disease, which typically appears macrovesicular. Microvesicular steatosis is associated with acute mitochondrial dysfunction and liver failure. Fat metabolic processes in hepatocytes whose dysregulation leads to the development of steatosis include secretion of lipoprotein particles, uptake of remnant lipoprotein particles or free fatty acids from blood, de novo lipogenesis, oxidation of fatty acids, lipolysis and lipophagy. Hepatic insulin resistance is a key feature of MASLD. Seipin is a polyfunctional protein that facilitates LD biogenesis. Assembly of hepatitis C virus takes place on LD surfaces. LDs make important, functional contact with the endoplasmic reticulum and other organelles.

CONCLUSIONS

Diverse liver pathologies are associated with hepatic steatosis, with MASLD being the most important contributor. The biogenesis and dynamics of LDs in hepatocytes are complex and warrant further investigation. Organellar interfaces permit co-regulation of lipid metabolism to match generation of potentially toxic lipid species with their LD depot storage.

Histological improvements following energy restriction and exercise: The role of insulin resistance in resolution of MASH

BACKGROUND & AIMS

Metabolic-dysfunction associated steatohepatitis (MASH) is one of the most common liver diseases worldwide and is characterized by multi-tissue insulin resistance. The effects of a 10-month energy restriction and exercise intervention on liver histology, anthropometrics, plasma biochemistries, and insulin sensitivity were compared to standard of care (control) to understand mechanisms that support liver health improvements.

METHODS

Following medical diagnosis of MASH, subjects were randomized to treatment (n=16) or control (n=8). Liver fat (MRS), 18-hour plasma biochemical measurements, and isotopically-labeled hyperinsulinemic-euglycemic clamps were completed pre- and post-intervention. Body composition and cardiorespiratory fitness (VO2peak) were also measured mid-intervention. Treatment subjects were counseled to reduce energy intake and completed supervised, high-intensity interval training (3x/week) for 10 months. Control subjects continued physician-directed care.

RESULTS

Treatment induced significant (P<0.05) reductions in body weight, fat mass, and liver injury, while VO2peak (P<0.05) and fatty acid (NEFA) suppression (P=0.06) were improved. Both groups exhibited reductions in total energy intake, HbA1c, hepatic insulin resistance, and liver fat (P<0.05). Compared to control, treatment induced a two-fold increase in peripheral insulin sensitivity which was significantly related to higher VO2peak and resolution of liver disease, despite no group differences in peripheral insulin sensitivity.

CONCLUSIONS

Exercise and energy-restriction elicited significant and clinically-meaningful treatment effects on liver health, potentially driven by a redistribution of excess nutrients to skeletal muscle, thereby reducing hepatic nutrient toxicity. Clinical guidelines should emphasize the addition of aerobic exercise in lifestyle treatments for the greatest histologic benefit in individuals with advanced MASH.

CLINICAL TRIAL NUMBER

NCT03151798.

Metabolic complications of psychotropic medications in psychiatric disorders: Emerging role of de novo lipogenesis and therapeutic consideration

Although significant advances have been made in understanding the patho-physiology of psychiatric disorders (PDs), therapeutic advances have not been very convincing. While psychotropic medications can reduce classical symptoms in patients with PDs, their long-term use has been reported to induce or exaggerate various pre-existing metabolic abnormalities including diabetes, obesity and non-alcoholic fatty liver disease (NAFLD). The mechanism(s) underlying these metabolic abnormalities is not clear; however, lipid/fatty acid accumulation due to enhanced de novo lipogenesis (DNL) has been shown to reduce membrane fluidity, increase oxidative stress and inflammation leading to the development of the aforementioned metabolic abnormalities. Intriguingly, emerging evidence suggest that DNL dysregulation and fatty acid accumulation could be the major mechanisms associated with the development of obesity, diabetes and NAFLD after long-term treatment with psychotropic medications in patients with PDs. In support of this, several adjunctive drugs comprising of anti-oxidants and anti-inflammatory agents, that are used in treating PDs in combination with psychotropic medications, have been shown to reduce insulin resistance and development of NAFLD. In conclusion, the above evidence suggests that DNL could be a potential pathological factor associated with various metabolic abnormalities, and a new avenue for translational research and therapeutic drug designing in PDs.

Oligonucleotide therapies for nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) represents a severe disease subtype of nonalcoholic fatty liver disease (NAFLD) that is thought to be highly associated with systemic metabolic abnormalities. It is characterized by a series of substantial liver damage, including hepatocellular steatosis, inflammation, and fibrosis. The end stage of NASH, in some cases, may result in cirrhosis and hepatocellular carcinoma (HCC). Nowadays a large number of investigations are actively under way to test various therapeutic strategies, including emerging oligonucleotide drugs (e.g., antisense oligonucleotide, small interfering RNA, microRNA, mimic/inhibitor RNA, and small activating RNA) that have shown high potential in treating this fatal liver disease. This article systematically reviews the pathogenesis of NASH/NAFLD, the promising druggable targets proven by current studies in chemical compounds or biological drug development, and the feasibility and limitations of oligonucleotide-based therapeutic approaches under clinical or pre-clinical studies.

Emerging role of natural lipophagy modulators in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is a seriously increasing liver disorder affecting nearly 32% of adults globally. Hepatic triglycerides (TG) accumulation is the hallmark of MASLD, which results from dysregulated lipid and fatty acid uptake, increased de novo lipogenesis (DNL), and decreased lipid removal. More recently, selective autophagy of lipid droplets (LDs), termed lipophagy, has emerged to be closely associated with disrupted hepatic lipid homeostasis. Recent studies have indicated that a series of natural products have shown promise as an alternative approach in attenuating MASLD via regulating lipophagy in vivo and in vitro. Therefore, lipophagy could be a new approach for natural products to be used to improve MASLD. This article aims to provide a comprehensive overview on the interrelationship between dysregulated lipid metabolism, lipophagy, and MASLD pathogenesis. In addition, the role of some natural products as lipophagy modulators and their impact on MASLD will be discussed.

Envisioning how to advance the MASH field

Since 1980, the cumulative effort of scientists and health-care stakeholders has advanced the prerequisites to address metabolic dysfunction-associated steatotic liver disease (MASLD), a prevalent chronic non-communicable liver disease. This effort has led to, among others, the approval of the first drug specific for metabolic dysfunction-associated steatohepatitis (MASH; formerly known as nonalcoholic steatohepatitis). Despite substantial progress, MASLD is still a leading cause of advanced chronic liver disease, including primary liver cancer. This Perspective contextualizes the nomenclature change from nonalcoholic fatty liver disease to MASLD and proposes important considerations to accelerate further progress in the field, optimize patient-centric multidisciplinary care pathways, advance pharmacological, behavioural and diagnostic research, and address health disparities. Key regulatory and other steps necessary to optimize the approval and access to upcoming additional pharmacological therapeutic agents for MASH are also outlined. We conclude by calling for increased education and awareness, enhanced health system preparedness, and concerted action by policy-makers to further the public health and policy agenda to achieve at least parity with other non-communicable diseases and to aid in growing the community of practice to reduce the human and economic burden and end the public health threat of MASLD and MASH by 2030.

Biomimetic MicroRNAs-Selenium-Nanocomposites for Targeted and Combined Hyperlipidemia Therapy

Hyperlipidemia is considered as a high-risk factor for leading to coronary heart disease. MicroRNA-148a-3p (miR-148a-3p) inhibitor is a potential therapeutic target to bind low-density lipoprotein cholesterol receptors (LDLR) for decreasing the levels of low-density lipoprotein cholesterol in plasma. However, the therapeutic effects are not ideal in the clinical translation of nucleic acids treatment, owing to the short circulation time in vivo. Therefore, a platelet membrane (PM) cloaks Se nanoparticles (SeNPs) delivery system with chitosan (CS) modifies and miR-148a-3p inhibitors encapsulated is designed (PM/CS-SeNPs/miR). The PM/CS-SeNPs/miR shows a uniform shell-core structure with a particle size of ≈90 nm. Co-delivering miR-148a-3p inhibitors and Se effectively alleviate hyperlipidemia via LDLR pathway and Toll-Like Receptor 4 (TLR-4)/NF-κB signaling pathway, respectively. Furthermore, coated by PM, PM/CS-SeNPs/miR successfully prolong circulation time to 48 h in vivo and quickly target to liver with no toxicity. This dual combination therapy with miRNAs and Se based on nanoparticles targeted delivery presents a high-performance strategy for precise hyperlipidemia treatment.

A long-acting LEAP2 analog reduces hepatic steatosis and inflammation and causes marked weight loss in mice

OBJECTIVE

The number of individuals affected by metabolic dysfunction associated fatty liver disease [1] is on the rise, yet hormonal contributors to the condition remain incompletely described and only a single FDA-approved treatment is available. Some studies suggest that the hormones ghrelin and LEAP2, which act as agonist and antagonist/inverse agonist, respectively, for the G protein coupled receptor GHSR, may influence the development of MAFLD. For instance, ghrelin increases hepatic fat whereas synthetic GHSR antagonists do the opposite. Also, hepatic steatosis is less prominent in standard chow-fed ghrelin-KO mice but more prominent in 42% high-fat diet-fed female LEAP2-KO mice.

METHODS

Here, we sought to determine the therapeutic potential of a long-acting LEAP2 analog (LA-LEAP2) to treat MAFLD in mice. LEAP2-KO and wild-type littermate mice were fed a Gubra-Amylin-NASH (GAN) diet for 10 or 40 wks, with some randomized to an additional 28 or 10 days of GAN diet, respectively, while treated with LA-LEAP2 vs Vehicle. Various metabolic parameters were followed and biochemical and histological assessments of MAFLD were made.

RESULTS

Among the most notable metabolic effects, daily LA-LEAP2 administration to both LEAP2-KO and wild-type littermates during the final 4 wks of a 14 wk-long GAN diet challenge markedly reduced liver weight, hepatic triglycerides, plasma ALT, hepatic microvesicular steatosis, hepatic lobular inflammation, NASH activity scores, and prevalence of higher-grade fibrosis. These changes were accompanied by prominent reductions in body weight, without effects on food intake, and reduced plasma total cholesterol. Daily LA-LEAP2 administration during the final 10 d of a 41.5 wk-long GAN diet challenge also reduced body weight, plasma ALT, and plasma total cholesterol in LEAP2-KO and wild-type littermates and prevalence of higher grade fibrosis in LEAP2-KO mice.

CONCLUSIONS

Administration of LA-LEAP2 to mice fed a MAFLD-prone diet markedly improves several facets of MAFLD, including hepatic steatosis, hepatic lobular inflammation, higher-grade hepatic fibrosis, and transaminitis. These changes are accompanied by prominent reductions in body weight and lowered plasma total cholesterol. Taken together, these data suggest that LEAP2 analogs such as LA-LEAP2 hold promise for the treatment of MAFLD and obesity.

Surveillance of the liver in type 2 diabetes: important but unfeasible?

Fatty liver plays a pivotal role in the pathogenesis of the metabolic syndrome and type 2 diabetes. According to an updated classification, any individual with liver steatosis and one or more features of the metabolic syndrome, without excess alcohol consumption or other known causes of steatosis, has metabolic dysfunction-associated steatotic liver disease (MASLD). Up to 60-70% of all individuals with type 2 diabetes have MASLD. However, the prevalence of advanced liver fibrosis in type 2 diabetes remains uncertain, with reported estimates of 10-20% relying on imaging tests and likely overestimating the true prevalence. All stages of MASLD impact prognosis but fibrosis is the best predictor of all-cause and liver-related mortality risk. People with type 2 diabetes face a two- to threefold increase in the risk of liver-related death and hepatocellular carcinoma, with 1.3% progressing to severe liver disease over 7.7 years. Because reliable methods for detecting steatosis are lacking, MASLD mostly remains an incidental finding on imaging. Regardless, several medical societies advocate for universal screening of individuals with type 2 diabetes for advanced fibrosis. Proposed screening pathways involve annual calculation of the Fibrosis-4 (FIB-4) index, followed by a secondary test such as transient elastography (TE) for intermediate-to-high-risk individuals. However, owing to unsatisfactory biomarker specificity, these pathways are expected to channel approximately 40% of all individuals with type 2 diabetes to TE and 20% to tertiary care, with a false discovery rate of up to 80%, raising concerns about feasibility. There is thus an urgent need to develop more effective strategies for surveying the liver in type 2 diabetes. Nonetheless, weight loss through lifestyle changes, pharmacotherapy or bariatric surgery remains the cornerstone of management, proving highly effective not only for metabolic comorbidities but also for MASLD. Emerging evidence suggests that fibrosis biomarkers may serve as tools for risk-based targeting of weight-loss interventions and potentially for monitoring response to therapy.

The signaling pathways in obesity-related complications

Obesity, a rapidly expanding epidemic worldwide, is known to exacerbate many medical conditions, making it a significant factor in multiple diseases and their associated complications. This threatening epidemic is linked to various harmful conditions such as type 2 diabetes mellitus, hypertension, metabolic dysfunction-associated steatotic liver disease, polycystic ovary syndrome, cardiovascular diseases (CVDs), dyslipidemia, and cancer. The rise in urbanization and sedentary lifestyles creates an environment that fosters obesity, leading to both psychosocial and medical complications. To identify individuals at risk and ensure timely treatment, it is crucial to have a better understanding of the pathophysiology of obesity and its comorbidities. This comprehensive review highlights the relationship between obesity and obesity-associated complications, including type 2 diabetes, hypertension, (CVDs), dyslipidemia, polycystic ovary syndrome, metabolic dysfunction-associated steatotic liver disease, gastrointestinal complications, and obstructive sleep apnea. It also explores the potential mechanisms underlying these associations. A thorough analysis of the interplay between obesity and its associated complications is vital in developing effective therapeutic strategies to combat the exponential increase in global obesity rates and mitigate the deadly consequences of this polygenic condition.

Deciphering the molecular pathways of saroglitazar: A dual PPAR α/γ agonist for managing metabolic NAFLD

Saroglitazar (SARO), a dual peroxisome proliferator activated receptor (PPAR)-α/γ agonist, has been used to treat metabolic diseases such as insulin resistance and diabetic dyslipidemia in patients with non-alcoholic fatty liver disease (NAFLD). SARO, administered at a dose of 4 mg/day, has been consistently studied in clinical trials with different time points ranging from 4 to 24 weeks with NAFLD patients. Due to its PPAR-γ agonistic action, SARO prevents adipose tissue-mediated fatty acid delivery to the liver by increasing insulin sensitivity and regulating adiponectin and leptin levels in adipose tissue. In hepatocytes, SARO induces fatty acid β-oxidation in mitochondria and transcriptionally activates lipid metabolizing genes in peroxisomes. SARO inhibits insulin resistance, thereby preventing the activation of sterol regulatory element-binding proteins -1c and carbohydrate response element binding protein in hepatocytes through its PPAR-α agonistic action. SARO treatment reduces lipotoxicity-mediated oxidative stress by activating the nuclear factor erythroid 2-related factor 2 and transcriptionally expressing the antioxidants from the antioxidant response element in the nucleus through its PPAR-γ agonistic action. SARO provides a PPAR-α/γ-mediated anti-inflammatory effect by preventing the phosphorylation of mitogen-activated protein kinases (JNK and ERK) and nuclear factor kappa B in hepatocytes. Additionally, SARO interferes with transforming growth factor-β/Smad downstream signaling, thereby reducing liver fibrosis progression through its PPAR-α/γ agonistic actions. Thus, SARO improves insulin resistance and dyslipidemia in NAFLD, reduces lipid accumulation in the liver, and thereby prevents mitochondrial toxicity, oxidative stress, inflammation, and fibrosis progression. This review summarizes the possible molecular mechanism of SARO in the NAFLD.

Pharmacotherapeutic options for metabolic dysfunction-associated steatotic liver disease: where are we today?

INTRODUCTION

Metabolic dysfunction-associated steatotic liver disease (MASLD) is defined by hepatic steatosis and cardiometabolic risk factors like obesity, type 2 diabetes, and dyslipidemia. Persistent metabolic injury may promote inflammatory processes resulting in metabolic dysfunction-associated steatohepatitis (MASH) and liver fibrosis. Mechanistic insights helped to identify potential drug targets, thereby supporting the development of novel compounds modulating disease drivers.

AREAS COVERED

The U.S. Food and Drug Administration has recently approved the thyroid hormone receptor β-selective thyromimetic resmetirom as the first compound to treat MASH and liver fibrosis. This review provides a comprehensive overview of current and potential future pharmacotherapeutic options and their modes of action. Lessons learned from terminated clinical trials are discussed together with the first results of trials investigating novel combinational therapeutic approaches.

EXPERT OPINION

Approval of resmetirom as the first anti-MASH agent may revolutionize the therapeutic landscape. However, long-term efficacy and safety data for resmetirom are currently lacking. In addition, heterogeneity of MASLD reflects a major challenge to define effective agents. Several lead compounds demonstrated efficacy in reducing obesity and hepatic steatosis, while anti-inflammatory and antifibrotic effects of monotherapy appear less robust. Better mechanistic understanding, exploration of combination therapies, and patient stratification hold great promise for MASLD therapy.

Metabolic Responses to an Acute Glucose Challenge: The Differential Effects of Eight Weeks of Almond vs. Cracker Consumption in Young Adults

This study investigated the dynamic responses to an acute glucose challenge following chronic almond versus cracker consumption for 8 weeks (clinicaltrials.gov ID: NCT03084003). Seventy-three young adults (age: 18-19 years, BMI: 18-41 kg/m2) participated in an 8-week randomized, controlled, parallel-arm intervention and were randomly assigned to consume either almonds (2 oz/d, n=38) or an isocaloric control snack of graham crackers (325 kcal/d, n=35) daily for 8 weeks. Twenty participants from each group underwent a 2-hour oral glucose tolerance test (oGTT) at the end of the 8-week intervention. Metabolite abundances in the oGTT serum samples were quantified using untargeted metabolomics, and targeted analyses for free PUFAs, total fatty acids, oxylipins, and endocannabinoids. Multivariate, univariate, and chemical enrichment analyses were conducted to identify significant metabolic shifts. Findings exhibit a biphasic lipid response distinguished by higher levels of unsaturated triglycerides in the earlier periods of the oGTT followed by lower levels in the latter period in the almond versus cracker group (p-value<0.05, chemical enrichment analyses). Almond (vs. cracker) consumption was also associated with higher AUC120 min of aminomalonate, and oxylipins (p-value<0.05), but lower AUC120 min of L-cystine, N-acetylmannosamine, and isoheptadecanoic acid (p-value<0.05). Additionally, the Matsuda Index in the almond group correlated with AUC120 min of CE 22:6 (r=-0.46; p-value<0.05) and 12,13 DiHOME (r=0.45; p-value<0.05). Almond consumption for 8 weeks leads to dynamic, differential shifts in response to an acute glucose challenge, marked by alterations in lipid and amino acid mediators involved in metabolic and physiological pathways.

Exploring the impact of lipid droplets on the evolution and progress of hepatocarcinoma

Over the past 10 years, the biological role of lipid droplets (LDs) has gained significant attention in the context of both physiological and pathological conditions. Considerable progress has been made in elucidating key aspects of these organelles, yet much remains to be accomplished to fully comprehend the myriad functions they serve in the progression of hepatic tumors. Our current perception is that LDs are complex and active structures managed by a distinct set of cellular processes. This understanding represents a significant paradigm shift from earlier perspectives. In this review, we aim to recapitulate the function of LDs within the liver, highlighting their pivotal role in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) (Hsu and Loomba, 2024) and their contribution to the progression towards more advanced pathological stages up to hepatocellular carcinoma (HC) (Farese and Walther, 2009). We are aware of the molecular complexity and changes occurring in the neoplastic evolution of the liver. Our attempt, however, is to summarize the most important and recent roles of LDs across both healthy and all pathological liver states, up to hepatocarcinoma. For more detailed insights, we direct readers to some of the many excellent reviews already available in the literature (Gluchowski et al., 2017; Hu et al., 2020; Seebacher et al., 2020; Paul et al., 2022).

Associations between estimated glucose disposal rate and arterial stiffness and mortality among US adults with non-alcoholic fatty liver disease

Background

The estimated glucose disposal rate (eGDR), an effective indicator of insulin resistance, has been related to acute coronary syndrome, ischemic stroke and heart failure. This study aims to explore the relationship between eGDR and arterial stiffness, all-cause mortality and cardiovascular mortality in patients with non-alcoholic fatty liver disease (NAFLD).

Methods

Participants with NAFLD were chosen from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2018. The main outcomes are arterial stiffness (represented by estimated pulse wave velocity, ePWV), all-cause and cardiovascular mortality. Multiple cox regression models, restricted cubic spline, sensitivity analysis and subgroup analysis were carried out to investigate the correlation between the insulin resistance indicators and mortality and arterial stiffness. Furthermore, receiver operating characteristic curves were used to compare the predictive value of the eGDR with the triglyceride-glucose (TyG) index and the homeostasis model assessment of insulin resistance (HOMA-IR) for all-cause and cardiovascular mortality.

Results

In this study, a total of 4,861 participants were included for analysis. After adjusting confounding factors in the multivariate weighted cox regression model, the eGDR was inversely associated with the all-cause mortality (Q4 vs. Q1, HR =0.65 (0.48-0.89, P=0.01) and cardiovascular mortality (Q4 vs. Q1, HR =0.35 (0.19-0.65, P<0.001). Compared with TyG index and HOMA-IR, the eGDR shows excellent predictive value in all-cause mortality (0.588 vs. 0.550 vs. 0.513, P < 0.001) and cardiovascular mortality (0.625 vs. 0.553 vs. 0.537, P < 0.001). In addition, we found a significant negative correlation between eGDR and arterial stiffness (β=-0.13(-0.14-0.11, P< 0.001). However, TyG index and HOMA-IR showed no significant correlation to arterial stiffness.

Conclusions

Low eGDR (an indicator of insulin resistance) levels are related to an increased risk of arterial stiffness and mortality in NAFLD patients in the United States.

Hepatic selective insulin resistance at the intersection of insulin signaling and metabolic dysfunction-associated steatotic liver disease

Insulin resistance (IR) is a major pathogenic factor in the progression of MASLD. In the liver, insulin suppresses gluconeogenesis and enhances de novo lipogenesis (DNL). During IR, there is a defect in insulin-mediated suppression of gluconeogenesis, but an unrestrained increase in hepatic lipogenesis persists. The mechanism of increased hepatic steatosis in IR is unclear and remains controversial. The key discrepancy is whether insulin retains its ability to directly regulate hepatic lipogenesis. Blocking insulin/IRS/AKT signaling reduces liver lipid deposition in IR, suggesting insulin can still regulate lipid metabolism; hepatic glucose metabolism that bypasses insulin's action may contribute to lipogenesis; and due to peripheral IR, other tissues are likely to impact liver lipid deposition. We here review the current understanding of insulin's action in governing different aspects of hepatic lipid metabolism under normal and IR states, with the purpose of highlighting the essential issues that remain unsettled.

Metabolic-associated fatty liver disease is characterized by a post-oral glucose load hyperinsulinemia in individuals with mild metabolic alterations

Metabolic-associated fatty liver disease (MAFLD) has been identified as risk factor of incident type 2 diabetes (T2D), but the underlying postprandial mechanisms remain unclear. We compared the glucose metabolism, insulin resistance, insulin secretion, and insulin clearance post-oral glucose tolerance test (OGTT) between individuals with and without MAFLD. We included 50 individuals with a body mass index (BMI) between 25 and 40 kg/m2 and ≥1 metabolic alteration: increased fasting triglycerides or insulin, plasma glucose 5.5-6.9 mmol/L, or glycated hemoglobin 5.7-5.9%. Participants were grouped according to MAFLD status, defined as hepatic fat fraction (HFF) ≥5% on MRI. We used oral minimal model on a frequently sampled 3 h 75 g-OGTT to estimate insulin sensitivity, insulin secretion, and pancreatic β-cell function. Fifty percent of participants had MAFLD. Median age (IQR) [57 (45-65) vs. 57 (44-63) yr] and sex (60% vs. 56% female) were comparable between groups. Post-OGTT glucose concentrations did not differ between groups, whereas post-OGTT insulin concentrations were higher in the MAFLD group (P < 0.03). Individuals with MAFLD exhibited lower insulin clearance, insulin sensitivity, and first-phase pancreatic β-cell function. In all individuals, increased insulin incremental area under the curve and decreased insulin clearance were associated with HFF after adjusting for age, sex, and BMI (P < 0.02). Among individuals with metabolic alterations, the presence of MAFLD was characterized mainly by post-OGTT hyperinsulinemia and reduced insulin clearance while exhibiting lower first phase β-cell function and insulin sensitivity. This suggests that MAFLD is linked with impaired insulin metabolism that may precede T2D.NEW & NOTEWORTHY Using an oral glucose tolerance test, we found hyperinsulinemia, lower insulin sensitivity, lower insulin clearance, and lower first-phase pancreatic β-cell function in individuals with MAFLD. This may explain part of the increased risk of incident type 2 diabetes in this population. These data also highlight implications of hyperinsulinemia and impaired insulin clearance in the progression of MAFLD to type 2 diabetes.

Paediatric steatotic liver disease has unique characteristics: A multisociety statement endorsing the new nomenclature

Nonalcoholic fatty liver disease (NAFLD) has been a commonly used term and diagnosis in paediatric hepatology, gastroenterology, and endocrinology clinics for over 30 years. A multisociety Delphi process has determined a new name "Steatotic Liver Disease" (SLD) as the overarching term for disorders associated with hepatic lipid accumulation. Our Societies give our support to steatotic liver disease as the best overarching term for use in our communities. Metabolic dysfunction-associated steatotic liver disease (MASLD) overcomes many of the shortcomings of the name NAFLD. Here, we highlight several points of the new nomenclature that are of particular importance for our community and their consequences for implementation including: diagnostic criteria, considering alternate diagnoses, practical implementation, research, advocacy, and education for paediatricians. As with all nomenclature changes, it will take a concerted effort from our paediatric societies to help integrate the optimal use of this into practice.

Animal studies of sodium-glucose co-transporter 2 inhibitors in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is considered one of the most common chronic liver diseases. Modern lifestyle, characterized by increasing rates of obesity and type 2 diabetes mellitus (T2DM), has led to a "pandemic" of NAFLD that imposes a personal health and socioeconomic burden. Apart from overnutrition and insulin resistance, various metabolic aberrations, gut microbiota and genetic predispositions are involved in the pathogenesis of the disease. The multifactorial nature of NAFLD's pathogenesis makes the development of pharmacological therapies for patients with this disease challenging. Sodium-glucose co-transporter 2 inhibitors (SGLT-2i) are antidiabetic agents that reduce blood glucose mainly by increasing its renal excretion. As T2DM is one of the major contributors to NAFLD, SGLT-2i have emerged as promising agents for the management of NAFLD. In this review, we summarize the main animal studies on SGLT-2i in models of NAFLD.

Autophagy and the unfolded protein response shape the non-alcoholic fatty liver landscape: decoding the labyrinth

The incidence of nonalcoholic fatty liver disease (NAFLD) is on the rise, mirroring a global surge in diabetes and metabolic syndrome, as its major leading causes. NAFLD represents a spectrum of liver disorders, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), which can potentially progress to cirrhosis and hepatocellular carcinoma (HCC). Mechanistically, we know the unfolded protein response (UPR) as a protective cellular mechanism, being triggered under circumstances of endoplasmic reticulum (ER) stress. The hepatic UPR is turned on in a broad spectrum of liver diseases, including NAFLD. Recent data also defines molecular mechanisms that may underlie the existing correlation between UPR activation and NAFLD. More interestingly, subsequent studies have demonstrated an additional mechanism, i.e. autophagy, to be involved in hepatic steatosis, and thus NAFLD pathogenesis, principally by regulating the insulin sensitivity, hepatocellular injury, innate immunity, fibrosis, and carcinogenesis. All these findings suggest possible mechanistic roles for autophagy in the progression of NAFLD and its complications. Both UPR and autophagy are dynamic and interconnected fluxes that act as protective responses to minimize the harmful effects of hepatic lipid accumulation, as well as the ER stress during NAFLD. The functions of UPR and autophagy in the liver, together with findings of decreased hepatic autophagy in correlation with conditions that predispose to NAFLD, such as obesity and aging, suggest that autophagy and UPR, alone or combined, may be novel therapeutic targets against the disease. In this review, we discuss the current evidence on the interplay between autophagy and the UPR in connection to the NAFLD pathogenesis.

Depression and NAFLD risk: A meta-analysis and Mendelian randomization study

BACKGROUND

Both depression and nonalcoholic fatty liver disease (NAFLD) have a high global prevalence. Growing evidence suggests an association between depression and NAFLD, while the association remains unclear. Thus, in this study, we aimed to explore the effect of depression on the risk of developing NAFLD.

METHODS

The meta-analysis examined the association between depression and the risk of NAFLD by including observational studies. Relevant studies were searched in PubMed, Embase, the Cochrane Library, and Web of Science. Then a two-sample Mendelian randomization (MR) analysis was performed to explore causal association using genetic instruments identified from a genome-wide association study.

RESULTS

Six eligible studies were included in the meta-analysis, involving 289,22 depression cases among 167,554 participants. Meta-analysis showed a significant association between depression and a higher risk of developing NAFLD (OR = 1.14, 95 % CI: [1.05, 1.24], P = 0.002). However, we found no convincing evidence supporting a causal role of genetically predicted depression with NAFLD risk (OR = 0.861, 95 % CI: [0.598, 1.238], P = 0.420).

LIMITATIONS

The insufficient number of included studies, the use of summary-level data, and restrictions on population sources are the major limiting factors.

CONCLUSIONS

Meta-analysis and MR analysis demonstrated inconsistent results on the relationship between depression and a high risk of developing NAFLD. Specifically, meta-analysis confirmed that depression increases the risk of developing NAFLD, while MR analysis did not support a causal association between genetically determined depression and the risk of NAFLD.

Association between processed and unprocessed red meat consumption and risk of nonalcoholic fatty liver disease: A systematic review and dose-response meta-analysis

Background

The nature of the relationship between red meat consumption and nonalcoholic fatty liver disease (NAFLD) remains unclear. Through this meta-analysis, we aimed to determine the association and dose-response relationship between red meat consumption (both processed and unprocessed) and the risk of NAFLD.

Methods

We systematically searched CENTRAL, PubMed, Embase, Web of Science and Scopus from inception to February 2022 for observational studies in which the exposure of interest was red meat consumption; the outcome of interest was the risk of NAFLD; and where odds ratios (ORs) or risk ratios were provided or could be calculated. We used random-effects meta-analyses to pool the effect sizes and performed analyses to estimate the linearity of the dose-response relationships between red meat intake and NAFLD risk.

Results

We included 10 studies in this review. The meta-analysis showed a significant association between the intake of red meat (OR = 1.27; 95% confidence interval (CI) = 1.07-1.50, P = 0.000, I2 = 81%), processed red meat (OR = 1.20; 95% CI = 1.04-1.3, P = 0.162, I2 = 34.9%) or unprocessed red meat (OR = 1.28; 95% CI = 1.05-1.55, P = 0.001, I2 = 76.2%) and the risk of NAFLD. We also found a significant linear dose-response association between processed red meat intake and NAFLD, with each 25-g increment of processed red meat intake per day was associated with an 11.1% higher risk of NAFLD (OR = 1.11; 95% CI = 1.01-1.22, P = 0.029), and a nonlinear association between unprocessed meat intake and NAFLD (P = 0.003 for nonlinearity).

Conclusions

Our findings indicate a potential positive association between red meat consumption (both processed and unprocessed) and NAFLD risk, especially in relation to increased intake of processed red meat compared to unprocessed red meat. However, caution is advised in interpreting these results; further research could establish a clearer understanding of the relationship between red meat consumption and NAFLD risk.

Registration

PROSPERO: CRD42022332839.

Potassium affects the association between dietary intake of vitamin C and NAFLD among adults in the United States

INTRODUCTION

Although the association between nonalcoholic fatty liver disease (NAFLD) and vitamin C has been well studied, the effects of dietary potassium intake on this relationship are still unclear. Thus, this study aimed to determine the effects of dietary potassium intake on the association between vitamin C and NAFLD.

METHODS

We performed a cross-sectional learn about with 9443 contributors the usage of 2007-2018 NHANES data. Multiple logistic regression evaluation has been utilized to check out the affiliation of dietary vitamin C intake with NAFLD and advanced hepatic fibrosis (AHF). Subsequently, we plotted a smoothed match curve to visualize the association. Especially, the analysis of AHF was conducted among the NAFLD population. In addition, stratified evaluation used to be developed primarily based on demographic variables to verify the steadiness of the results. Effect amendment by way of dietary potassium intake used to be assessed via interplay checks between vitamin C and NAFLD in the multivariable linear regression.

RESULTS

In this cross-sectional study, we found that vitamin C was negatively related to NAFLD and AHF. The relationship between vitamin C and NAFLD was different in the low, middle and high potassium intake groups. Furthermore, potassium intake significantly modified the negative relationship between vitamin C and NAFLD in most of the models.

CONCLUSION

Our research showed that potassium and vitamin C have an interactive effect in reducing NAFLD, which may have great importance for clinical medication.

Interleukin-27 as a novel player in alleviating hepatic steatosis: Mechanistic insights from an in vitro analysis

Interleukin-27 (IL-27) is a recently discovered cytokine that has been implicated in inflammatory and metabolic conditions, such as atherosclerosis and insulin resistance. However, the mechanisms by which IL-27 attenuates hepatic lipid accumulation in hyperlipidemic conditions and counteracts endoplasmic reticulum (ER) stress, a known risk factor for impaired hepatic lipid metabolism, have not been elucidated. This in vitro study was designed to examine the effect of IL-27 on hepatic lipid metabolism. The study included the evaluation of lipogenesis-associated proteins and ER stress markers by Western blotting, the determination of hepatic lipid accumulation by Oil Red O staining, and the examination of autophagosome formation by MDC staining. The results showed that IL-27 treatment reduced lipogenic lipid deposition and the expression of ER stress markers in cultured hepatocytes exposed to palmitate. Moreover, treatment with IL-27 suppressed CD36 expression and enhanced fatty acid oxidation in palmitate-treated hepatocytes. The effects of IL-27 on hyperlipidemic hepatocytes were attenuated when adenosine monophosphate-activated protein kinase (AMPK) or 3-methyladenine (3 MA) were inhibited by small interfering RNA (siRNA). These results suggest that IL-27 attenuates hepatic ER stress and fatty acid uptake and stimulates fatty acid oxidation via AMPK/autophagy signaling, thereby alleviating hepatic steatosis. In conclusion, this study identified IL-27 as a promising therapeutic target for nonalcoholic fatty liver disease (NAFLD).

Cardiometabolic characteristics of people with metabolically healthy and unhealthy obesity

There is considerable heterogeneity in the cardiometabolic abnormalities associated with obesity. We evaluated multi-organ system metabolic function in 20 adults with metabolically healthy obesity (MHO; normal fasting glucose and triglycerides, oral glucose tolerance, intrahepatic triglyceride content, and whole-body insulin sensitivity), 20 adults with metabolically unhealthy obesity (MUO; prediabetes, hepatic steatosis, and whole-body insulin resistance), and 15 adults who were metabolically healthy lean. Compared with MUO, people with MHO had (1) altered skeletal muscle biology (decreased ceramide content and increased expression of genes involved in BCAA catabolism and mitochondrial structure/function); (2) altered adipose tissue biology (decreased expression of genes involved in inflammation and extracellular matrix remodeling and increased expression of genes involved in lipogenesis); (3) lower 24-h plasma glucose, insulin, non-esterified fatty acids, and triglycerides; (4) higher plasma adiponectin and lower plasma PAI-1 concentrations; and (5) decreased oxidative stress. These findings provide a framework of potential mechanisms responsible for MHO and the metabolic heterogeneity of obesity. This study was registered at ClinicalTrials.gov (NCT02706262).

Hepatopancreatic metabolic disorders and their implications in the development of Alzheimer's disease and vascular dementia

Dementia has been faced with significant public health challenges and economic burdens that urges the need to develop safe and effective interventions. In recent years, an increasing number of studies have focused on the relationship between dementia and liver and pancreatic metabolic disorders that result in diseases such as diabetes, obesity, hypertension and dyslipidemia. Previous reports have shown that there is a plausible correlation between pathologies caused by hepatopancreatic dysfunctions and dementia. Glucose, insulin and IGF-1 metabolized in the liver and pancreas probably have an important influence on the pathophysiology of the most common dementias: Alzheimer's and vascular dementia. This current review highlights recent studies aimed at identifying convergent mechanisms, such as insulin resistance and other diseases, linked to altered hepatic and pancreatic metabolism, which are capable of causing brain changes that ultimately lead to dementia.

A Review: Cytochrome P450 in Alcoholic and Non-Alcoholic Fatty Liver Disease

Alcoholic fatty liver disease (FALD) and non-alcoholic fatty liver disease (NAFLD) have similar pathological spectra, both of which are associated with a series of symptoms, including steatosis, inflammation, and fibrosis. These clinical manifestations are caused by hepatic lipid synthesis and metabolism dysregulation and affect human health. Despite having been studied extensively, targeted therapies remain elusive. The Cytochrome P450 (CYP450) family is the most important drug-metabolising enzyme in the body, primarily in the liver. It is responsible for the metabolism of endogenous and exogenous compounds, completing biological transformation. This process is relevant to the occurrence and development of AFLD and NAFLD. In this review, the correlation between CYP450 and liver lipid metabolic diseases is summarised, providing new insights for the treatment of AFLD and NAFLD.

The pathophysiology of MASLD: an immunometabolic perspective

INTRODUCTION

Metabolic-associated liver diseases have emerged pandemically across the globe and are clinically related to metabolic disorders such as obesity and type 2 diabetes. The new nomenclature and definition (i.e. metabolic dysfunction-associated steatotic liver disease - MASLD; metabolic dysfunction-associated steatohepatitis - MASH) reflect the nature of these complex systemic disorders, which are characterized by inflammation, gut dysbiosis and metabolic dysregulation. In this review, we summarize recent advantages in understanding the pathophysiology of MASLD, which we parallel to emerging therapeutic concepts.

AREAS COVERED

We summarize the pathophysiologic concepts of MASLD and its transition to MASH and subsequent advanced sequelae of diseases. Furthermore, we highlight how dietary constituents, microbes and associated metabolites, metabolic perturbations, and immune dysregulation fuel lipotoxicity, hepatic inflammation, liver injury, insulin resistance, and systemic inflammation. Deciphering the intricate pathophysiologic processes that contribute to the development and progression of MASLD is essential to develop targeted therapeutic approaches to combat this escalating burden for health-care systems.

EXPERT OPINION

The rapidly increasing prevalence of metabolic dysfunction-associated steatotic liver disease challenges health-care systems worldwide. Understanding pathophysiologic traits is crucial to improve the prevention and treatment of this disorder and to slow progression into advanced sequelae such as cirrhosis and hepatocellular carcinoma.