Nonalcoholic fatty liver disease: pathology and pathogenesis

Sirtuins and Gut Microbiota: Dynamics in Health and a Journey from Metabolic Dysfunction to Hepatocellular Carcinoma

Metabolic dysfunction leading to non-alcoholic fatty liver disease (NAFLD) exhibits distinct molecular and immune signatures that are influenced by factors like gut microbiota. The gut microbiome interacts with the liver via a bidirectional relationship with the gut-liver axis. Microbial metabolites, sirtuins, and immune responses are pivotal in different metabolic diseases. This extensive review explores the complex and multifaceted interrelationship between sirtuins and gut microbiota, highlighting their importance in health and disease, particularly metabolic dysfunction and hepatocellular carcinoma (HCC). Sirtuins (SIRTs), classified as a group of NAD+-dependent deacetylases, serve as crucial modulators of a wide spectrum of cellular functions, including metabolic pathways, the inflammatory response, and the process of senescence. Their subcellular localization and diverse functions link them to various health conditions, including NAFLD and cancer. Concurrently, the gut microbiota, comprising diverse microorganisms, significantly influences host metabolism and immune responses. Recent findings indicate that sirtuins modulate gut microbiota composition and function, while the microbiota can affect sirtuin activity. This bidirectional relationship is particularly relevant in metabolic disorders, where dysbiosis contributes to disease progression. The review highlights recent findings on the roles of specific sirtuins in maintaining gut health and their implications in metabolic dysfunction and HCC development. Understanding these interactions offers potential therapeutic avenues for managing diseases linked to metabolic dysregulation and liver pathology.

Prevalence and Risk Factors of Type 2 Diabetes Mellitus among Depression Inpatients from 2005 to 2018 in Beijing, China

Background: There are few data on the comorbidity of diabetes in Chinese patients with depression. We aimed to calculate the prevalence and explore risk factors of type 2 diabetes mellitus (T2DM) among depression inpatients from 2005 to 2018 in Beijing. Methods: This study is a cross-sectional study. The data collected from 19 specialized psychiatric hospitals in Beijing were analyzed. The prevalence of T2DM and its distribution were analyzed. The multivariable logistic regression was performed to explore the risk factors of T2DM. Results: A total of 20,899 depression inpatients were included. The prevalence of T2DM was 9.13% [95% confidence interval (CI), 8.74% to 9.52%]. The prevalence of T2DM showed an upward trend with year (P for trend < 0.001) and age (P for trend < 0.001). The prevalence of T2DM was higher among readmitted patients (12.97%) and patients with comorbid hypertension (26.16%), hyperlipidemia (21.28%), and nonalcoholic fatty liver disease (NAFLD) (18.85%). The prevalence of T2DM in females was lower than in males among patients aged 18 to 59 years, while the prevalence of T2DM in females was higher than in males among patients aged ≥60 years. T2DM was associated with older age [adjusted odds ratios (aORs) ranged from 3.68 to 29.95, P < 0.001], hypertension (aOR, 3.01; 95% CI, 2.70 to 3.35; P < 0.001), hyperlipidemia (aOR, 1.69; 95% CI, 1.50 to 1.91; P < 0.001), and NAFLD (aOR, 1.58; 95% CI, 1.37 to 1.82; P < 0.001). Conclusions: The prevalence of T2DM among depression inpatients from 2005 to 2018 in Beijing was high and increased with the year. Depression inpatients who were older and with hypertension, hyperlipidemia, and NAFLD had a higher prevalence and risk of T2DM.

Relationship between plasma 12,13-diHOME level and nonalcoholic fatty liver disease in patients with type 2 diabetes and obesity

BACKGROUND

12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME) was one of the newly found lipokines. The goal of this study was to investigate whether the 12,13-diHOME was associated with related metabolic markers of nonalcoholic fatty liver disease (NAFLD) in a Chinese population with type 2 diabetes (T2DM) and obesity.

METHODS

This cross-sectional study enrolled 202 subjects with T2DM. Anthropometric parameters, 12,13-diHOME, serum lipids levels, fasting blood-glucose (FBG), serum glycosylated hemoglobin (HbA1c), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), liver and kidney function parameters were collected. NAFLD was diagnosed based on abdominal ultrasonography examination results. A computer-aided ultrasound quantitative method was applied to evaluate the liver fat content (LFC).

RESULTS

The number of the patients with fatty liver was 139 (68.81%) and those with non-fatty liver was 63 (31.19%). Subjects with NAFLD had a higher body mass index (BMI), diastolic blood pressure, serum alanine aminotransferase (ALT), triglyceride (TG), HOMA-IR, LFC, P<0.05 for all. But no significant difference was found in plasma 12,13-diHOME level (P=0.967), though its level trend was higher in non-NAFLD group. Plasma 12,13-diHOME was positively correlated with aspartate aminotransferase (AST), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), blood urea nitrogen (BUN), free fatty acid (FFA), C-peptide, FINS and HOMA-IR. It was negatively correlated with height, body weight, glomerular filtration rate (eGFR) and HbA1c.

CONCLUSIONS

Although 12,13-diHOME was correlated with AST, TC, HDL-C, BUN, FFA, C-peptide, FINS, HOMA-IR, eGFR and HbA1c, there was no significant difference in 12,13-diHOME level between the two groups. However, more research should be carried on about this newly-found lipokine.

Mechanisms underpinning the effect of exercise on the non-alcoholic fatty liver disease: review

Non-alcoholic Fatty Liver Disease (NAFLD) - whose terminology was recently replaced by metabolic liver disease (MAFLD) - is an accumulation of triglycerides in the liver of >5 % of its weight. Epidemiological studies indicated an association between NAFLD and reduced physical activity. In addition, exercise has been shown to improve NAFLD independently of weight loss. In this paper, we aim to systematically review molecular changes in sedentary experimental NAFLD models vs. those subjected to exercise. We utilized the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and standard review techniques. Studies were considered for inclusion if they addressed the primary question: the mechanisms by which exercise influenced NAFLD. This review summarized experimental evidence of improvements in NAFLD with exercise in the absence of weight loss. The pathways involved appeared to have AMPK as a common denominator. See also the graphical abstract(Fig. 1).

Smad4 deficiency in hepatocytes attenuates NAFLD progression via inhibition of lipogenesis and macrophage polarization

Nonalcoholic fatty liver disease (NAFLD), a major cause of chronic liver disorders, has become a serious public health issue. Although the Smad4 signaling pathway has been implicated in the progression of NAFLD, the specific role of Smad4 in hepatocytes in NAFLD pathogenesis remains unclear. Hepatocyte-specific knockout Smad4 mice (AlbSmad4-/-) were first constructed using the Cre-Loxp recombinant system to establish a high-fat diet induced NAFLD model. The role of Smad4 in the occurrence and development of NAFLD was determined by monitoring the body weight of mice, detecting triglycerides and free fatty acids in serum and liver tissue homogenates, staining the tissue sections to observe the accumulation of liver fat, and RT-qPCR detecting the expression of genes related to lipogenesis, fatty acid intake, and fatty acid β oxidation. The molecular mechanism of Smad4 in hepatocytes affecting NAFLD was therefore investigated through combining in vitro and in vivo experiments. Smad4 deficiency in hepatocytes mitigated NAFLD progression and decreased inflammatory cell infiltration. Moreover, Smad4 deficiency inhibited CXCL1 secretion by suppressing the activation of the ASK1/P38/JNK signaling pathway. Furthermore, targeting CXCL1 using CXCR2 inhibitors diminished hepatocyte lipogenesis and inhibited the polarization of M1-type macrophages. Collectively, these results suggested that Smad4 plays a vital role in exacerbating NAFLD and may be a promising candidate for anti-NAFLD therapy.

Roles of X-box binding protein 1 in liver pathogenesis

The prevalence of drug-induced liver injury (DILI) and viral liver infections presents significant challenges in modern healthcare and contributes to considerable morbidity and mortality worldwide. Concurrently, metabolic dysfunctionassociated steatotic liver disease (MASLD) has emerged as a major public health concern, reflecting the increasing rates of obesity and leading to more severe complications such as fibrosis and hepatocellular carcinoma. X-box binding protein 1 (XBP1) is a distinct transcription factor with a basic-region leucine zipper structure, whose activity is regulated by alternative splicing in response to disruptions in endoplasmic reticulum (ER) homeostasis and the unfolded protein response (UPR) activation. XBP1 interacts with a key signaling component of the highly conserved UPR and is critical in determining cell fate when responding to ER stress in liver diseases. This review aims to elucidate the emerging roles and molecular mechanisms of XBP1 in liver pathogenesis, focusing on its involvement in DILI, viral liver infections, MASLD, fibrosis/cirrhosis, and liver cancer. Understanding the multifaceted functions of XBP1 in these liver diseases offers insights into potential therapeutic strategies to restore ER homeostasis and mitigate liver damage.

Galectin-3 in metabolic disorders: mechanisms and therapeutic potential

Galectin-3 (Gal3), a β-galactoside-binding lectin, is expressed predominantly in immunological and inflammatory cells. Gal3 expression is elevated in metabolic diseases, including obesity, diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD), and plays an important role in the progression of these diseases. In this review, we summarize the structure and post-translational modifications of Gal3 and the cellular functions of Gal3 according to its subcellular localization. We focused on the pathological functions and molecular mechanisms of Gal3 in various cell types. In particular, extracellular Gal3 and intracellular Gal3 may have different physiological and pathological functions. We also discuss promising Gal3 inhibitors or antibodies that are currently in clinical trials and outstanding questions and challenges for future pursuit.

Fatty acids and epigenetics in health and diseases

Lipids are crucial for human health and reproduction and include diverse fatty acids (FAs), notably polyunsaturated FAs (PUFAs) and short-chain FAs (SCFAs) that are known for their health benefits. Bioactivities of PUFAs, including ω-6 and ω-3 FAs as well as SCFAs, have been widely studied in various tissues and diseases. Epigenetic regulation has been suggested as a significant mechanism affecting the progression of various diseases, including cancers and metabolic and inflammatory diseases. Epigenetics encompasses the reversible modulation of gene expression without altering the DNA sequence itself, mediated by mechanisms such as DNA methylation, histone acetylation, and chromatin remodeling. Bioactive FAs have been demonstrated to regulate gene expression via epigenetic modifications that are potentially important for modulating metabolic control and disease risk. This review paper discusses the evidence in support of bioactive FAs, including ω-6 and ω-3 FAs and SCFAs, eliciting various disease prevention via epigenetic regulation including methylation or acetylation.

Graphical abstract

Therapeutic effects of FGF21 mimetic bFKB1 on MASH and atherosclerosis in Ldlr-/-.Leiden mice

Fibroblast growth factor 21 (FGF21) is a promising target for treatment of obesity-associated diseases including metabolic dysfunction-associated steatohepatitis (MASH) and atherosclerosis. We evaluated the effects of the bispecific anti-FGF21-β klotho (KLB) agonist antibody bFKB1 in a preclinical model of MASH and atherosclerosis. Low-density lipoprotein receptor knockout (Ldlr-/-).Leiden mice received a high-fat diet for 20 weeks, followed by treatment with an isotype control antibody or bFKB1 for 12 weeks. Effects on plasma risk markers and (histo)pathology of liver, adipose tissue, and heart were evaluated alongside hepatic transcriptomics analysis. bFKB1 lowered body weight (-21%) and adipose tissue mass (-22%) without reducing food intake. The treatment also improved plasma insulin (-80%), cholesterol (-48%), triglycerides (-76%), alanine transaminase (ALT: -79%), and liver weight (-43%). Hepatic steatosis and inflammation were strongly reduced (macrovesicular steatosis -34%; microvesicular steatosis -100%; inflammation -74%) and while the total amount of fibrosis was not affected, bFKB1 did decrease new collagen formation (-49%). Correspondingly, hepatic transcriptomics and pathway analysis revealed the mechanistic background underlying these histological improvements, demonstrating broad inactivation of inflammatory and profibrotic transcriptional programs by bFKB1. In epididymal white adipose tissue, bFKB1 reduced adipocyte size (-16%) and inflammation (-52%) and induced browning, signified by increased uncoupling protein-1 (UCP1) protein expression (8.5-fold increase). In the vasculature, bFKB1 had anti-atherogenic effects, lowering total atherosclerotic lesion area (-38%). bFKB1 has strong beneficial metabolic effects associated with a reduction in hepatic steatosis, inflammation, and atherosclerosis. Analysis of new collagen formation and profibrotic transcriptional programs indicate that bFKB1 treatment may have antifibrotic potential in a longer treatment duration as well.

Caffeine mitigates tamoxifen-induced fatty liver in Wistar rats

PURPOSE

Tamoxifen, a widely used drug for breast cancer treatment, is associated with adverse effects on the liver, including the development of fatty liver. This study aimed to investigate the potential protective effect of caffeine against tamoxifen-induced fatty liver in Wistar rats.

METHODS

Rats were divided into normal control, tamoxifen + saline, and tamoxifen + caffeine. Plasma samples were assessed for biochemical markers related to oxidative stress, inflammation, liver function, and cell damage. Additionally, liver histopathology was examined to quantify the extent of fatty infiltration.

RESULTS

In the tamoxifen + saline group, elevated levels of plasma malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), alanine aminotransferase (ALT), cytokeratin 18, and soluble ST2 were observed compared to the normal control group, indicating increased oxidative stress, inflammation, and liver injury (p < 0.01). Moreover, histopathological examination revealed a significant increase in fatty infiltration (p < 0.001). However, in the tamoxifen + caffeine group, these markers were markedly reduced (p < 0.05, p < 0.01), and fatty infiltration was significantly mitigated (p < 0.001).

CONCLUSIONS

The findings suggest that caffeine administration attenuates tamoxifen-induced fatty liver in rats by ameliorating oxidative stress, inflammation, liver injury, and cell damage. Histopathological evidence further supports the protective role of caffeine. This study highlights the potential of caffeine as a therapeutic intervention to counter tamoxifen-induced hepatic complications, contributing to the optimization of breast cancer treatment strategies.

Downregulation of Setdb2 promotes alternative activation of macrophages via the PI3K/Akt pathway to attenuate NAFLD after sleeve gastrectomy

Non-alcoholic fatty liver disease (NAFLD) stands as the most prevalent hepatic disorder, with bariatric surgery emerging as the most effective intervention for NAFLD remission. Sleeve gastrectomy (SG) has notably ascended as the predominant procedure due to its comparative simplicity and consistent surgical outcomes. Nonetheless, the underlying mechanisms remain unclear. In this study, we probed the therapeutic potential of SG for NAFLD induced by a high-fat diet (HFD) in mice, with a focus on its impact on liver lipid accumulation, macrophage polarization, and the role of the histone methyltransferase Setdb2. SG prompted significant weight loss, diminished liver size and liver-to-body weight ratio, and enhanced liver function, evidenced by reduced serum levels of triglycerides (TG), total cholesterol (T-CHO), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Histological examination confirmed a reduction in liver lipid accumulation. Additionally, flow cytometry unveiled an increased proportion of M2 macrophages and a decrease in Setdb2 expression was shown in the SG group, suggesting an association between Setdb2 levels and postsurgical macrophage polarization. Furthermore, the conditional knockout of Setdb2 in mice further mitigated HFD-induced steatosis and promoted the M2 macrophage phenotype. Mechanistically, Setdb2 knockout in bone marrow-derived macrophages (BMDMs) favored M2 polarization, with RNA sequencing and western blotting analyses corroborating the upregulation of the PI3K/Akt signaling pathway. The effects of Setdb2 on macrophage activation were nullified by the PI3K inhibitor LY294002, suggesting that Setdb2 facilitates alternative macrophage activation through the PI3K/Akt signaling pathway. These comprehensive findings underscore the potential of SG as a therapeutic intervention for NAFLD by regulating the critical function of Setdb2 in macrophage polarization and activation, thereby offering novel insights into NAFLD pathogenesis and therapeutic targets.

Global Prevalence of Nonalcoholic Fatty Liver Disease: An Updated Review Meta-Analysis comprising a Population of 78 million from 38 Countries

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a global health challenge, with a rising rate in line with other metabolic diseases. We aimed to assess the global prevalence of NAFLD in adult and pediatric populations.

METHODS

PubMed, Scopus and Web of Science databases were systematically searched up to May 2023. Heterogeneity was assessed using Cochran's Q test and I2 statistics, and random-effects model was used for meta-analysis. Analyses were performed using STATA version 18.

RESULTS

A total of 479 studies with 78,001,755 participants from 38 countries were finally included. The global prevalence of NAFLD was estimated to be 30.2% (95% CI: 28.7-31.7%). Regionally, the prevalence of NAFLD was as follows: Asia 30.9% (95% CI: 29.2-32.6%), Australia 16.1% (95% CI: 9.0-24.8%), Europe 30.2% (95% CI: 25.6-35.0%), North America 29% (95% CI: 25.8-32.3%), and South America 34% (95% CI: 16.9-53.5%). Countries with a higher human development index (HDI) had significantly lower prevalence of NAFLD (coefficient = -0.523, p = 0.005). Globally, the prevalence of NAFLD in men and women was 36.6% (95% CI: 34.7-38.4%) and 25.5% (95% CI: 23.9-27.1%), respectively. The prevalence of NAFLD in adults, adults with obesity, children, and children with obesity was 30.2% (95% CI: 28.8-31.7%), 57.5% (95% CI: 43.6-70.9%), 14.3% (95% CI: 10.3-18.8%), and 38.0% (95% CI: 31.5-44.7%), respectively.

CONCLUSION

The prevalence of NAFLD is remarkably high, particularly in countries with lower HDI. This substantial prevalence in both adults and children underscores the need for disease management protocols to reduce the burden.

miR-33 deletion in hepatocytes attenuates MASLD-MASH-HCC progression

The complexity of the mechanisms underlying metabolic dysfunction-associated steatotic liver disease (MASLD) progression remains a significant challenge for the development of effective therapeutics. miRNAs have shown great promise as regulators of biological processes and as therapeutic targets for complex diseases. Here, we study the role of hepatic miR-33, an important regulator of lipid metabolism, during the progression of MASLD and the development of hepatocellular carcinoma (HCC). We report that miR-33 was elevated in the livers of humans and mice with MASLD and that its deletion in hepatocytes (miR-33 HKO) improved multiple aspects of the disease, including steatosis and inflammation, limiting the progression to metabolic dysfunction-associated steatotic hepatitis (MASH), fibrosis, and HCC. Mechanistically, hepatic miR-33 deletion reduced lipid synthesis and promoted mitochondrial fatty acid oxidation, reducing lipid burden. Additionally, absence of miR-33 altered the expression of several known miR-33 target genes involved in metabolism and resulted in improved mitochondrial function and reduced oxidative stress. The reduction in lipid accumulation and liver injury resulted in decreased YAP/TAZ pathway activation, which may be involved in the reduced HCC progression in HKO livers. Together, these results suggest suppressing hepatic miR-33 may be an effective therapeutic approach to temper the development of MASLD, MASH, and HCC in obesity.

The predictive role of the platelet-to-lymphocyte ratio for the risk of non-alcoholic fatty liver disease and cirrhosis: a nationwide cross-sectional study

Background

The associations between platelet-to-lymphocyte ratio (PLR) and non-alcoholic fatty liver disease (NAFLD) and cirrhosis are unclear, and there are still no effective means for diagnosing or monitoring disease progression.

Methods

Data from the National Health and Nutrition Examination Surveys were collected for analysis. Logistic regression and restricted cubic splines were used to evaluate the associations between PLR and NAFLD and cirrhosis in different populations. The Area Under Curve Receiver Operating Characteristic (AUCROC) was used to distinguish the models. Threshold analysis was performed by constructing a two-piecewise linear regression. Correlation analysis was performed separately on either side of the inflection point.

Results

A total of 5724 adults were included. Logistic regression analysis revealed that the PLR was associated with NAFLD and cirrhosis (AUCROC of NAFLD: 0.803; AUCROC of cirrhosis: 0.851). The AUCROC of the PLR for predicting NAFLD incidence was 0.762 in the diabetic population and 0.804 in the nondiabetic population. High PLR predicted cirrhosis in the diabetic population, with an AUCROC of 0.824, whereas a high PLR was not associated with cirrhosis in the nondiabetic population. The restricted cubic spline revealed a negative linear correlation between the PLR and NAFLD incidence. The inflection point of the PLR for NAFLD was 180.74. A PLR ≤180.74 was statistically significant (odds ratio=0.997, 95% confidence interval=0.995-0.999). In the NAFLD population, the PLR was negatively correlated with cirrhosis at a PLR ≤130.5 (odds ratio=0.987, 95% confidence interval=0.977-0.996) and positively correlated with cirrhosis at a PLR > 130.5 (odds ratio=1.006, 95% confidence interval=1.001-1.012).

Conclusions

The PLR and NAFLD were negatively correlated in the U.S. population. The PLR had a U-shaped relationship with cirrhosis in the NAFLD population. The PLR has potential value in monitoring NAFLD patient progression to cirrhosis.

An unbiased ranking of murine dietary models based on their proximity to human metabolic dysfunction-associated steatotic liver disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease, encompasses steatosis and metabolic dysfunction-associated steatohepatitis (MASH), leading to cirrhosis and hepatocellular carcinoma. Preclinical MASLD research is mainly performed in rodents; however, the model that best recapitulates human disease is yet to be defined. We conducted a wide-ranging retrospective review (metabolic phenotype, liver histopathology, transcriptome benchmarked against humans) of murine models (mostly male) and ranked them using an unbiased MASLD 'human proximity score' to define their metabolic relevance and ability to induce MASH-fibrosis. Here, we show that Western diets align closely with human MASH; high cholesterol content, extended study duration and/or genetic manipulation of disease-promoting pathways are required to intensify liver damage and accelerate significant (F2+) fibrosis development. Choline-deficient models rapidly induce MASH-fibrosis while showing relatively poor translatability. Our ranking of commonly used MASLD models, based on their proximity to human MASLD, helps with the selection of appropriate in vivo models to accelerate preclinical research.

Intravoxel incoherent motion assessment of liver fibrosis staging in MASLD

PURPOSE

Partial correlation analysis was performed to account for the interference of steatosis changes and inflammatory factors, to determine the true correlation between fibrosis and IVIM parameters (Dfast, Dslow, and F), and to evaluate the diagnostic efficacy of IVIM for liver fibrosis.

METHODS

A total of 106 patients with metabolic dysfunction-associated steatotic liver disease (MASLD) examined by IVIM from November 2016 to November 2023 at our hospital were retrospectively included. Preliminary analysis of each IVIM parameter and correlations with pathological findings were performed using Spearman correlation analysis, and partial correlation analysis was used to exclude the interference of other pathological factors, thus yielding the true correlations between IVIM parameters (Dfast, Dslow, and F) and pathology. The diagnostic efficacy of IVIM parameters for diagnosing MASLD was assessed via receiver operating characteristic (ROC) curve analysis.

RESULTS

Spearman correlation analysis of all the IVIM parameters revealed correlations with steatosis, lobular inflammation, and ballooning. Partial correlation analysis indicated that Dfast was correlated with the pathological fibrosis stage (r = - 0.593, P < 0.001), Dslow was correlated with the pathological steatosis score (r = - 0.313, P < 0.05), and F was correlated with the pathological fibrosis stage and steatosis score (r = - 0.456 and 0.255, P < 0.001 and P < 0.05). In the diagnosis of hepatic fibrosis, significant hepatic fibrosis, advanced liver fibrosis and cirrhosis, Dfast achieved areas under the ROC curve of 0.763, 0.801, 0.853, and 0.897, respectively. The threshold values for diagnosing different fibrosis stages using Dfast (10-3 mm2/s) were 57.613, 54.587, 52.714, and 51.978, respectively.

CONCLUSION

According to our partial correlation analysis, there was a moderate correlation between Dfast and F according to fibrosis stage, and Dfast was not influenced by inflammation or steatosis when diagnosing fibrosis in MASLD patients. A relatively close Dfast threshold is insufficient for accurately and noninvasively assessing various stages of MASLD fibrosis. In clinical practice, this approach can be considered an alternative method for the preliminary assessment of fibrosis in MASLD patients.

Differences in diacylglycerol acyltransferases expression patterns and regulation cause distinct hepatic triglyceride deposition in fish

Triglyceride (TAG) deposition in the liver is associated with metabolic disorders. In lower vertebrate, the propensity to accumulate hepatic TAG varies widely among fish species. Diacylglycerol acyltransferases (DGAT1 and DGAT2) are major enzymes for TAG synthesis. Here we show that large yellow croaker (Larimichthys crocea) has significantly higher hepatic TAG level than that in rainbow trout (Oncorhynchus mykiss) fed with same diet. Hepatic expression of DGATs genes in croaker is markedly higher compared with trout under physiological condition. Meanwhile, DGAT1 and DGAT2 in both croaker and trout are required for TAG synthesis and lipid droplet formation in vitro. Furthermore, oleic acid treatment increases DGAT1 expression in croaker hepatocytes rather than in trout and has no significant difference in DGAT2 expression in two fish species. Finally, effects of various transcription factors on croaker and trout DGAT1 promoter are studied. We find that DGAT1 is a target gene of the transcription factor CREBH in croaker rather than in trout. Overall, hepatic expression and transcriptional regulation of DGATs display significant species differences between croaker and trout with distinct hepatic triglyceride deposition, which bring new perspectives on the use of fish models for studying hepatic TAG deposition.

Effects of repeated weight cycling on non-alcoholic steatohepatitis in diet-induced obese mice

Lifestyle interventions remain the treatment of choice for patients with obesity and metabolic complications, yet are difficult to maintain and often lead to cycles of weight loss and regain (weight cycling). Literature on weight cycling remains controversial and we therefore investigated the association between weight cycling and metabolic complications using preexistent obese mice. Ldlr-/-.Leiden mice received a high-fat diet (HFD) for 20 weeks to induce obesity. Subsequently, weight-cycled mice were switched between the healthy chow diet and HFD for four 2-week periods and compared to mice that received HFD for the total study period. Repeated weight cycling tended to decrease body weight and significantly reduced fat mass, whereas adipose tissue inflammation was similar relative to HFD controls. Weight cycling did not significantly affect blood glucose or plasma insulin levels yet significantly reduced plasma free fatty acid and alanine transaminase/aspartate transaminase levels. Hepatic macrovesicular steatosis was similar and microvesicular steatosis tended to be increased upon weight cycling. Weight cycling resulted in a robust decrease in hepatic inflammation compared to HFD controls while hepatic fibrosis and atherosclerosis development were not affected. These results argue against the postulate that repeated weight cycling leads to unfavorable metabolic effects, when compared to a continuous unhealthy lifestyle, and in fact revealed beneficial effects on hepatic inflammation, an important hallmark of non-alcoholic steatohepatitis.

DA-6034 ameliorates hepatic steatosis and inflammation in high fat diet-induced obese mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is characterized by an increase in hepatic triglyceride content and increased inflammatory macrophage infiltration through the C-C motif chemokine receptor (CCR) 5 pathway in the liver. DA-6034 (7-carboxymethyloxy-3',4',5-trimethoxy flavone), is a synthetic derivative of eupatilin that exhibits anti-inflammatory activity in inflammatory bowel disease. However, the effect of DA-6034 on the inflammatory response in NAFLD is not well elucidated. Therefore, we aimed to determine the effect of DA-6034 on hepatic steatosis and inflammation.

METHODS

Forty male C57BL/6J mice were divided into the following four groups: (1) regular diet (RD), (2) RD with DA-6034, (3) high fat diet (HFD), and (4) HFD with DA-6034. All mice were sacrificed 12 weeks after the start of the experiment. The effects of DA-6034 on macrophages were assessed using RAW264.7 cells.

RESULTS

DA-6034 not only reduced hepatic triglyceride levels and lipid accumulation but also macrophage infiltration and proinflammatory cytokines in HFD-fed mice. According to fluorescence-activated cell sorter analysis, DA-6034 reduced the CD8+ T cell fraction in the liver of HFD-fed mice. DA-6034 also reduced CCR5 expression and the migration of liver macrophages in HFD-fed mice and inhibited CCR2 ligand and CCR4 ligand, which stimulated the migration of macrophages.

CONCLUSION

Overall, DA-6034 attenuates hepatic steatosis and inflammation in obesity by regulating CCR5 expression in macrophages.

Changes in proteomic cargo of circulating extracellular vesicles in response to lifestyle intervention in adolescents with hepatic steatosis

BACKGROUND

Recent studies suggest that proteomic cargo of extracellular vesicles (EVs) may play a role in metabolic improvements following lifestyle interventions. However, the relationship between changes in liver fat and circulating EV-derived protein cargo following intervention remains unexplored.

METHODS

The study cohort comprised 18 Latino adolescents with obesity and hepatic steatosis (12 males/6 females; average age 13.3 ± 1.2 y) who underwent a six-month lifestyle intervention. EV size distribution and concentration were determined by light scattering intensity; EV protein composition was characterized by liquid chromatography tandem-mass spectrometry.

RESULTS

Average hepatic fat fraction (HFF) decreased 23% by the end of the intervention (12.5% [5.5] to 9.6% [4.9]; P = 0.0077). Mean EV size was smaller post-intervention compared to baseline (120.2 ± 16.4 nm to 128.4 ± 16.5 nm; P = 0.031), although the difference in mean EV concentration (1.1E+09 ± 4.1E+08 particles/mL to 1.1E+09 ± 1.8E+08 particles/mL; P = 0.656)) remained unchanged. A total of 462 proteins were identified by proteomic analysis of plasma-derived EVs from participants pre- and post-intervention, with 113 proteins showing differential abundance (56 higher and 57 lower) between the two timepoints (adj-p <0.05). Pathway analysis revealed enrichment in complement cascade, initial triggering of complement, creation of C4 and C2 activators, and regulation of complement cascade. Hepatocyte-specific EV affinity purification identified 40 proteins with suggestive (p < 0.05) differential abundance between pre- and post-intervention samples.

CONCLUSIONS

Circulating EV-derived proteins, particularly those associated with the complement cascade, may contribute to improvements in liver fat in response to lifestyle intervention.

The Effects of Olive Oil Consumption on Biochemical Parameters and Body Mass Index of People with Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disorder, is closely associated with insulin resistance, obesity, and metabolic syndromes. A body of research has proposed that olive oil, a basic component of the Mediterranean diet with antioxidant and anti-inflammatory properties, may alleviate metabolic disturbances and retard the progression of NAFLD. We conducted a systematic review and meta-analysis to assess the effectiveness of olive oil intake in people with NAFLD. We systematically searched the major electronic databases (PubMed/MEDLINE, Scopus, Cochrane Central Register of Controlled Trials), as well as grey literature sources, to identify randomized controlled trials (RCTs) investigating the effects of olive oil consumption on biochemical and anthropometric parameters of individuals with NAFLD. The quality of the studies was evaluated using the risk-of-bias tool 2.0 (RoB 2). The mean difference (MD) and the 95% confidence interval (CI) were calculated using fixed-effects and random-effects models. Seven RCTs involving 515 subjects were included in the analysis. In the random-effects model, no statistically significant differences were identified with respect to alanine transaminase (MD = -1.83 IU/L, 95% CI: -5.85, 2.19 IU/L, p = 0.37, I2 = 69%) and aspartate transaminase (MD = -1.65 IU/L, 95% CI: -4.48, 1.17 IU/L, p = 0.25, I2 = 72%) levels or waist circumference values (MD = -0.23 cm, 95% CI: -1.23, 0.76 cm, p = 0.65, I2 = 0%). However, a significant effect on body mass index was observed (MD = -0.57 kg/m2, 95% CI: -1.08, -0.06 kg/m2, p = 0.03, I2 = 51%) for subjects who received olive oil compared to those who received an alternative diet or placebo. The findings of the present meta-analysis suggest a modestly positive impact of olive oil intake on body weight in people with NAFLD.

LncRNA LINK-A Remodels Tissue Inflammatory Microenvironments to Promote Obesity

High-fat diet (HFD)-induced obesity is a crucial risk factor for metabolic syndrome, mainly due to adipose tissue dysfunctions associated with it. However, the underlying mechanism remains unclear. This study has used genetic screening to identify an obesity-associated human lncRNA LINK-A as a critical molecule bridging the metabolic microenvironment and energy expenditure in vivo by establishing the HFD-induced obesity knock-in (KI) mouse model. Mechanistically, HFD LINK-A KI mice induce the infiltration of inflammatory factors, including IL-1β and CXCL16, through the LINK-A/HB-EGF/HIF1α feedback loop axis in a self-amplified manner, thereby promoting the adipose tissue microenvironment remodeling and adaptive thermogenesis disorder, ultimately leading to obesity and insulin resistance. Notably, LINK-A expression is positively correlated with inflammatory factor expression in individuals who are overweight. Of note, targeting LINK-A via nucleic acid drug antisense oligonucleotides (ASO) attenuate HFD-induced obesity and metabolic syndrome, pointing out LINK-A as a valuable and effective therapeutic target for treating HFD-induced obesity. Briefly, the results reveale the roles of lncRNAs (such as LINK-A) in remodeling tissue inflammatory microenvironments to promote HFD-induced obesity.

Oral supplementation of gut microbial metabolite indole-3-acetate alleviates diet-induced steatosis and inflammation in mice

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries. There is growing evidence that dysbiosis of the intestinal microbiota and disruption of microbiota-host interactions contribute to the pathology of NAFLD. We previously demonstrated that gut microbiota-derived tryptophan metabolite indole-3-acetate (I3A) was decreased in both cecum and liver of high-fat diet-fed mice and attenuated the expression of inflammatory cytokines in macrophages and Tnfa and fatty acid-induced inflammatory responses in an aryl-hydrocarbon receptor (AhR)-dependent manner in hepatocytes. In this study, we investigated the effect of orally administered I3A in a mouse model of diet-induced NAFLD. Western diet (WD)-fed mice given sugar water (SW) with I3A showed dramatically decreased serum ALT, hepatic triglycerides (TG), liver steatosis, hepatocyte ballooning, lobular inflammation, and hepatic production of inflammatory cytokines, compared to WD-fed mice given only SW. Metagenomic analysis show that I3A administration did not significantly modify the intestinal microbiome, suggesting that I3A's beneficial effects likely reflect the metabolite's direct actions on the liver. Administration of I3A partially reversed WD-induced alterations of liver metabolome and proteome, notably, decreasing expression of several enzymes in hepatic lipogenesis and β-oxidation. Mechanistically, we also show that AMP-activated protein kinase (AMPK) mediates the anti-inflammatory effects of I3A in macrophages. The potency of I3A in alleviating liver steatosis and inflammation clearly demonstrates its potential as a therapeutic modality for preventing the progression of steatosis to non-alcoholic steatohepatitis (NASH).

Discovery of dual rho-associated protein kinase 1 (ROCK1)/apoptosis signal-regulating kinase 1 (ASK1) inhibitors as a novel approach for non-alcoholic steatohepatitis (NASH) treatment

In the current study we suggest a novel approach to curb non-alcoholic steatohepatitis (NASH) progression, and we suggest privileged scaffolds for the design of novel compounds for this aim. NASH is an advanced form of non-alcoholic fatty liver disease that can further progress into fibrosis, cirrhosis, and hepatocellular carcinoma. It is a widely emerging disease affecting 25% of the global population and has no current approved treatments. Protein kinases are key regulators of cellular pathways, of which, Rho-associated protein kinase 1 (ROCK1) and apoptosis signal-regulating kinase 1 (ASK1) play an important role in the progression of NASH and they stand out as promising targets for NASH therapy. Interestingly, their kinase domains are found to be similar in sequence and topology; therefore, dual inhibition of ROCK1 and ASK1 is expected to be amenable and could achieve a more favourable outcome. To reach this goal, a training set of ROCK1 and ASK1 protein structures co-crystalized with type 1 (ATP-competitive) inhibitors was constructed to manually generate receptor-based pharmacophore models representing ROCK1 and ASK1 inhibitors' common pharmacophoric features. The models produced were assessed using a test set of both ROCK1 and ASK1 actives and decoys, and their performance was evaluated using different assessment metrics. The best pharmacophore model obtained, showing a Mathew's correlation coefficient (MCC) of 0.71, was then used to screen the ZINC purchasable database retrieving 6178 hits that were filtered accordingly using several medicinal chemistry and pharmacokinetics filters returning 407 promising compounds. To confirm that these compounds are capable of binding to the target kinases, they were subjected to molecular docking simulations at both protein structures. The results were then assessed individually and filtered, setting the spotlight on various privileged scaffolds that could be exploited as the nucleus for designing novel ROCK1/ASK1 dual inhibitors.

Marked difference in liver fat measured by histology vs. magnetic resonance-proton density fat fraction: A meta-analysis

Background & Aims

Pathologists quantify liver steatosis as the fraction of lipid droplet-containing hepatocytes out of all hepatocytes, whereas the magnetic resonance-determined proton density fat fraction (PDFF) reflects the tissue triacylglycerol concentration. We investigated the linearity, agreement, and correspondence thresholds between histological steatosis and PDFF across the full clinical spectrum of liver fat content associated with non-alcoholic fatty liver disease.

Methods

Using individual patient-level measurements, we conducted a systematic review and meta-analysis of studies comparing histological steatosis with PDFF determined by magnetic resonance spectroscopy or imaging in adults with suspected non-alcoholic fatty liver disease. Linearity was assessed by meta-analysis of correlation coefficients and by linear mixed modelling of pooled data, agreement by Bland-Altman analysis, and thresholds by receiver operating characteristic analysis. To explain observed differences between the methods, we used RNA-seq to determine the fraction of hepatocytes in human liver biopsies.

Results

Eligible studies numbered 9 (N = 597). The relationship between PDFF and histology was predominantly linear (r = 0.85 [95% CI, 0.80-0.89]), and their values approximately coincided at 5% steatosis. Above 5% and towards higher levels of steatosis, absolute values of the methods diverged markedly, with histology exceeding PDFF by up to 3.4-fold. On average, 100% histological steatosis corresponded to a PDFF of 33.0% (29.5-36.7%). Targeting at a specificity of 90%, optimal PDFF thresholds to predict histological steatosis grades were ≥5.75% for ≥S1, ≥15.50% for ≥S2, and ≥21.35% for S3. Hepatocytes comprised 58 ± 5% of liver cells, which may partly explain the lower values of PDFF vs. histology.

Conclusions

Histological steatosis and PDFF have non-perfect linearity and fundamentally different scales of measurement. Liver fat values obtained using these methods may be rendered comparable by conversion equations or threshold values.

Impact and implications

Magnetic resonance-proton density fat fraction (PDFF) is increasingly being used to measure liver fat in place of the invasive liver biopsy. Understanding the relationship between PDFF and histological steatosis fraction is important for preventing misjudgement of clinical status or treatment effects in patient care. Our analysis revealed that histological steatosis fraction is often significantly higher than PDFF, and their association varies across the spectrum of fatty liver severity. These findings are particularly important for physicians and clinical researchers, who may use these data to interpret PDFF measurements in the context of histologically evaluated liver fat content.

Fu Brick Tea as a Staple Food Supplement Attenuates High Fat Diet Induced Obesity in Mice

Fu brick tea (FBT), a product of microbial fermentation from primary dark tea, also known as raw material tea (RMT), has been extensively studied for its functional properties. However, its potential as a staple food supplement for weight loss remains poorly understood. This study compared the weight loss effects of orlistat, traditional plain noodles (NN), and noodles supplemented with varying amounts of RMT (RMTN) and FBT (FBTN), with the aim to elucidate their lipid-reducing effects and underlying mechanisms. Experimental trials on high fat diet fed mice revealed significant weight loss, lipid-lowering, and hypoglycemic effects upon supplementation with orlistat, RMTN, and FBTN. Moreover, supplementation with orlistat, RMTN, and FBTN effectively restored serum and liver-related index levels, mitigating high-fat diet-induced dyslipidemia. Additionally, these supplements ameliorated liver and kidney damage by inhibiting oxidative stress and inflammatory responses. Furthermore, orlistat, RMTN, and FBTN exert their anti-obesity effects primarily by modulating genes associated with lipid metabolism and inflammatory responses and through regulation of the composition and structure of the gut microbiota. Importantly, FBTN demonstrated a significantly stronger lipid-lowering effect compared to RMTN, particularly at higher tea addition ratios. In contrast, NN supplementation exhibited minimal to no weight loss effects. Based on these findings, it could be inferred that FBT holds promise as a staple food supplement to ameliorate high-fat diet-induced obesity and its associated health conditions.

Changes in liver metabolic pathways demonstrate efficacy of the combined dietary and microbial therapeutic intervention in MASLD mouse model

OBJECTIVE

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), is the most prevalent liver disease globally, yet no therapies are approved. The effects of Escherichia coli Nissle 1917 expressing aldafermin, an engineered analog of the intestinal hormone FGF19, in combination with dietary change were investigated as a potential treatment for MASLD.

METHODS

MASLD was induced in C57BL/6J male mice by American lifestyle-induced obesity syndrome diet and then switched to a standard chow diet for seven weeks. In addition to the dietary change, the intervention group received genetically engineered E. coli Nissle expressing aldafermin, while control groups received either E. coli Nissle vehicle or no treatment. MASLD-related plasma biomarkers were measured using an automated clinical chemistry analyzer. The liver steatosis was assessed by histology and bioimaging analysis using Fiji (ImageJ) software. The effects of the intervention in the liver were also evaluated by RNA sequencing and liquid-chromatography-based non-targeted metabolomics analysis. Pathway enrichment studies were conducted by integrating the differentially expressed genes from the transcriptomics findings with the metabolites from the metabolomics results using Ingenuity pathway analysis.

RESULTS

After the intervention, E. coli Nissle expressing aldafermin along with dietary changes reduced body weight, liver steatosis, plasma aspartate aminotransferase, and plasma cholesterol levels compared to the two control groups. The integration of transcriptomics with non-targeted metabolomics analysis revealed the downregulation of amino acid metabolism and related receptor signaling pathways potentially implicated in the reduction of hepatic steatosis and insulin resistance. Moreover, the downregulation of pathways linked to lipid metabolism and changes in amino acid-related pathways suggested an overall reduction of oxidative stress in the liver.

CONCLUSIONS

These data support the potential for using engineered microbial therapeutics in combination with dietary changes for managing MASLD.

A review of experimental and clinical studies on the therapeutic effects of pomegranate (Punica granatum) on non-alcoholic fatty liver disease: Focus on oxidative stress and inflammation

Non-alcoholic fatty liver disease (NAFLD) is frequently linked to metabolic disorders and is prevalent in obese and diabetic patients. The pathophysiology of NAFLD involves multiple factors, including insulin resistance (IR), oxidative stress (OS), inflammation, and genetic predisposition. Recently, there has been an emphasis on the use of herbal remedies with many people around the world resorting to phytonutrients or nutraceuticals for treatment of numerous health challenges in various national healthcare settings. Pomegranate (Punica granatum) parts, such as juice, peel, seed and flower, have high polyphenol content and is well known for its antioxidant capabilities. Pomegranate polyphenols, such as hydrolyzable tannins, anthocyanins, and flavonoids, have high antioxidant capabilities that can help lower the OS and inflammation associated with NAFLD. The study aimed to investigate whether pomegranate parts could attenuate OS, inflammation, and other risk factors associated with NAFLD, and ultimately prevent the development of the disease. The findings of this study revealed that: 1. pomegranate juice contains hypoglycemic qualities that can assist manage blood sugar levels, which is vital for avoiding and treating NAFLD. 2. Polyphenols from pomegranate flowers increase paraoxonase 1 (PON1) mRNA and protein levels in the liver, which can help protect liver enzymes and prevent NAFLD. 3. Punicalagin (PU) is one of the major ellagitannins found in pomegranate, and PU-enriched pomegranate extract (PE) has been shown to inhibit HFD-induced hyperlipidemia and hepatic lipid deposition in rats. 4. Pomegranate fruit consumption, which is high in antioxidants, can decrease the activity of AST and ALT (markers of liver damage), lower TNF-α (a marker of inflammation), and improve overall antioxidant capacity in NAFLD patients. Overall, the polyphenols in pomegranate extracts have antioxidant, anti-inflammatory, hypoglycemic, and protective effects on liver enzymes, which can help prevent and manage NAFLD effects on liver enzymes, which can help prevent and manage NAFLD.

The Outcomes of Liver Transplantation in Severe Metabolic Dysfunction-Associated Steatotic Liver Disease Patients

The increasing prevalence of diabetes mellitus, obesity, and metabolic syndrome in the population can lead to metabolic dysfunction-associated steatohepatitis (MASH) and metabolic dysfunction-associated steatotic liver disease (MASLD). In Western industrialized countries, this has become a major problem with significant socioeconomic impacts. MASH is now a leading cause of liver transplantation (LT), especially in developed countries. However, the post-transplant outcomes of such patients are a major concern, and published data are limited and extremely variable. In this article, we discuss graft and patient survival after LT, complications, the recurrence of MASH, and MASH appearing de novo after transplantation. Recent studies suggest that patients with MASH have slightly worse short-term survival, potentially due to increased cardiovascular mortality. However, most studies found that longer-term outcomes for patients undergoing LT for MASH are similar or even better than those for other indications. Hepatocellular carcinoma due to MASH cirrhosis also has similar or even better outcomes after LT than other etiologies. In conclusion, we suggest questions and topics that require further research to enhance healthcare for this growing patient population.

Associations of Macronutrients Intake With MRI-determined Hepatic Fat Content, Hepatic Fibroinflammation, and NAFLD

CONTEXT

A healthy lifestyle is the cornerstone of management in nonalcoholic fatty liver disease (NAFLD). However, the associations between dietary macronutrient composition and different aspects of NAFLD pathology are unclear and dietary recommendations for NAFLD are lacking.

OBJECTIVE

This work aimed to evaluate the associations of dietary macronutrient composition with hepatic steatosis, hepatic fibroinflammation, and NAFLD.

METHODS

In this cross-sectional study, a total of 12 620 UK Biobank participants who completed both the dietary questionnaire and magnetic resonance imaging (MRI) examination were included in this study. Dietary consumption of macronutrient was self-reported and calculated. MRI-determined hepatic fat content, fibroinflammation, and NAFLD were estimated.

RESULTS

First, we found that saturated fatty acid (SFA) intake was associated with higher hepatic steatosis, fibroinflammation, and NAFLD prevalence. In contrast, higher fiber or protein intake was reversely correlated with hepatic steatosis and fibroinflammation. Interestingly, starch or sugar intake was significantly associated with hepatic fibroinflammation, whereas monounsaturated fatty acid (MUFA) intake was negatively correlated with hepatic fibroinflammation. Isocaloric analysis revealed that replacing SFA with sugar, fiber, or protein was significantly associated with a reduction in hepatic steatosis, while replacing starch, sugar, or SFA with protein or MUFA was significantly correlated with a decrease in hepatic fibroinflammation.

CONCLUSION

Overall, our results demonstrate that specific macronutrients are associated with different aspects of NAFLD, and specific dietary compositions should be recommended for distinct NAFLD-risk populations.

Prospective comparison of liver stiffness measurement methods in surveillance biopsies after liver transplantation

Background

Liver stiffness measurements (LSMs) have proven useful for non-invasive detection of fibrosis. Previous studies of LSMs after transplantation were performed in cohorts dominated by hepatitis C reinfections and indication biopsies for the evaluation of graft dysfunction. However, the diagnostic fidelity of LSMs for fibrosis is biased by inflammation e.g., during replicative hepatitis C or rejection.

Materials and methods

The current study aimed for a head-to-head comparison of two different LSMs, acoustic radiation force impulse (ARFI) and transient elastography (TE), and a determination of cut-off values for the detection of advanced fibrosis (any LAF score component ≥2) in grafts undergoing surveillance biopsies (svLbx) without recurrent hepatitis C.

Results

103 svLbx were paired with valid LSMs at time of biopsy. AUROC analyses showed significant positive correlation with fibrosis for both methods (TE: AUROC = 0.819 (p < 0.001; 95%CI: 0.717-0.921); ARFI: AUROC = 0.771 (p = 0.001; 95%CI: 0.652-0.890). Patients were randomly assigned to training and validation cohorts for both LSM methods. Cut-off values were determined at 1.29 m/s (ARFI) and at 7.5 kPa (TE) in training cohorts. Sensitivity and specificity in training and validation cohorts were: TE: SEN 0.818 and 0.5; SPE 0.742 and 0.885; ARFI: SEN 0.818 and 1.0; SPE 0.75 and 0.586. LSMs were not associated with BANFF criteria for relevant graft injury.

Conclusion

LSM is a good non-invasive tool to screen for advanced graft fibrosis but not for relevant graft injury in patients with (near) normal liver enzymes. Fibrosis cut-off values identified and validated in svLbx were lower than in previous cohorts using indication biopsies.

Acyl CoA oxidase: from its expression, structure, folding, and import to its role in human health and disease

β-oxidation of fatty acids is an important metabolic pathway and is a shared function between mitochondria and peroxisomes in mammalian cells. On the other hand, peroxisomes are the sole site for the degradation of fatty acids in yeast. The first reaction of this pathway is catalyzed by the enzyme acyl CoA oxidase housed in the matrix of peroxisomes. Studies in various model organisms have reported the conserved function of the protein in fatty acid oxidation. The importance of this enzyme is highlighted by the lethal conditions caused in humans due to its altered function. In this review, we discuss various aspects ranging from gene expression, structure, folding, and import of the protein in both yeast and human cells. Further, we highlight recent findings on the role of the protein in human health and aging, and discuss the identified mutations in the protein associated with debilitating conditions in patients.

Application of multiple-finding segmentation utilizing Mask R-CNN-based deep learning in a rat model of drug-induced liver injury

Drug-induced liver injury (DILI) presents significant diagnostic challenges, and recently artificial intelligence-based deep learning technology has been used to predict various hepatic findings. In this study, we trained a set of Mask R-CNN-based deep algorithms to learn and quantify typical toxicant induced-histopathological lesions, portal area, and connective tissue in Sprague Dawley rats. We compared a set of single-finding models (SFMs) and a combined multiple-finding model (MFM) for their ability to simultaneously detect, classify, and quantify multiple hepatic findings on rat liver slide images. All of the SFMs yielded mean average precision (mAP) values above 85%, suggesting that the models had been successfully established. The MFM showed better performance than the SFMs, with a total mAP value of 92.46%. We compared the model predictions for slide images with ground-truth annotations generated by an accredited pathologist. For the MFM, the overall and individual finding predictions were highly correlated with the annotated areas, with R-squared values of 0.852, 0.952, 0.999, 0.990, and 0.958 being obtained for portal area, infiltration, necrosis, vacuolation, and connective tissue (including fibrosis), respectively. Our results indicate that the proposed MFM could be a useful tool for detecting and predicting multiple hepatic findings in basic non-clinical study settings.

Macrophage metabolism in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and its inflammatory and often progressive subtype nonalcoholic steatohepatitis (NASH), have emerged as significant contributors to hepatic morbidity worldwide. The pathophysiology of NAFLD/NASH is multifaceted, variable, and remains incompletely understood. The pivotal role of liver-resident and recruited macrophages in the pathogenesis of NAFLD and NASH is widely acknowledged as a crucial factor in innate immunity. The remarkable plasticity of macrophages enables them to assume diverse activation and polarization states, dictated by their immunometabolism microenvironment and functional requirements. Recent studies in the field of immunometabolism have elucidated that alterations in the metabolic profile of macrophages can profoundly influence their activation state and functionality, thereby influencing various pathological processes. This review primarily focuses on elucidating the polarization and activation states of macrophages, highlighting the correlation between their metabolic characteristics and the transition from pro-inflammatory to anti-inflammatory phenotypes. Additionally, we explore the potential of targeting macrophage metabolism as a promising therapeutic approach for the management of NAFLD/NASH.

Fatty infiltration of the pancreas: a systematic concept analysis

Fatty infiltration of the pancreas (FIP) has been recognized for nearly a century, yet many aspects of this condition remain unclear. Regular literature reviews on the diagnosis, consequences, and management of FIP are crucial. This review article highlights the various disorders for which FIP has been established as a risk factor, including type 2 diabetes mellitus (T2DM), pancreatitis, pancreatic fistula (PF), metabolic syndrome (MS), polycystic ovary syndrome (PCOS), and pancreatic duct adenocarcinoma (PDAC), as well as the new investigation tools. Given the interdisciplinary nature of FIP research, a broad range of healthcare specialists are involved. This review article covers key aspects of FIP, including nomenclature and definition of pancreatic fat infiltration, history and epidemiology, etiology and pathophysiology, clinical presentation and diagnosis, clinical consequences, and treatment. This review is presented in a detailed narrative format for accessibility to clinicians and medical students.

Pomegranate (Punica granatum L.) peel extract ameliorates metabolic syndrome risk factors in patients with non-alcoholic fatty liver disease: a randomized double-blind clinical trial

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is a metabolic syndrome (MS)-related liver disorder that has an increasing prevalence. Thus, the aim of our study is to evaluate the effects of pomegranate peel extract (PP) supplementation on hepatic status and metabolic syndrome risk factors.

METHODS

In phase one, the hydro-alcoholic extraction of the peel of 750 kg of pomegranate (Punica granatum L.) was performed by the soaking method. Then, in phase two, NAFLD patients received 1500 mg of placebo (n = 37) or pomegranate peel capsules (n = 39) with a 500-kcal deficit diet for 8 weeks. Gastrointestinal intolerance, dietary intake, lipid and glycemic profiles, systolic and diastolic blood pressure, body composition, insulin resistance indexes, and elastography-evaluated NAFLD changes were followed.

RESULTS

The mean age of participants was 43.1 ± 8.6 years (51.3% female). Following the intervention, the mean body weight (mean changes: -5.10 ± 2.30 kg), waist circumference (-7.57 ± 2.97 cm), body mass index (-1.82 ± 0.85 kg/m2), body fat index (-1.49 ± 0.86), and trunk fat (- 3.93 ± 3.07%), systolic (-0.63 ± 0.29 cmHg) and diastolic (-0.39 ± 0.19 cmHg) blood pressure, total cholesterol (-10.51 ± 0.77 mg/dl), triglyceride (-16.02 ± 1.7 mg/dl), low-density lipoprotein cholesterol (-9.33 ± 6.66 mg/dl; all P < 0.001), fat free mass (- 0.92 ± 0.90 kg; P < 0.003), and fasting blood sugar (-5.28 ± 1.36 mg/dl; P = 0.02) decreased significantly in PP in contrast to the placebo group in the raw model and when adjusted for confounders. Also, high-density lipoprotein cholesterol (5.10 ± 0.36 mg/dl), liver steatosis and stiffness (- 0.30 ± 0.17 and - 0.72 ± 0.35 kPa, respectively, all P < 0.001) improved in the PP group. However, fasting insulin (P = 0.81) and homeostatic model assessment for insulin resistance (HOMA-IR) (P = 0.93) were not significantly different when comparing two groups during the study in the raw and even adjusted models.

CONCLUSION

In conclusion, 1500 mg pomegranate peel extract along with a weight-loss diet improved metabolic syndrome risk factors and reduced hepatic steatosis in patients with NAFLD after 8 weeks.

Hepatic Fat and Macrophages Are Increased in Livers of Diabetic Patients without Non-Alcoholic Fatty Liver Disease

INTRODUCTION

Diabetes mellitus (DM), especially type 2, is strongly associated with non-alcoholic fatty liver disease (NAFLD). Recent studies indicate that particularly in DM patients, "simple" liver steatosis can progress into more severe disease. However, little is known about putative hepatic histopathological changes in DM patients without NAFLD. In this study, we therefore analysed fat content and inflammatory cell infiltration in the livers of deceased DM and non-DM patients without NAFLD, and analysed age/sex effects hereon.

METHODS

Hepatic fat and inflammatory cells were studied through (immuno)histochemical analysis in liver tissue from 24 DM patients and 66 non-diabetic controls, without histopathological characteristics of NAFLD.

RESULTS

We observed a 2-fold increase in fat percentage/mm2 and a near 5-fold increase in the number of fat-containing cells/mm2 in DM patients compared to non-diabetic controls. Fat content was significantly higher in patients with type 2 DM, but not type 1 DM, compared to non-diabetic controls, while the number of CD68+ cells/mm2 was significantly elevated in both DM groups.

CONCLUSION

Hepatic fat and number of macrophages are increased in patients with DM without NAFLD, which may reflect a higher risk on development of steatosis and steatohepatitis.

Anti-Angiogenic Effects of Natural Compounds in Diet-Associated Hepatic Inflammation

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are the most common causes of chronic liver disease and are increasingly emerging as a global health problem. Such disorders can lead to liver damage, resulting in the release of pro-inflammatory cytokines and the activation of infiltrating immune cells. These are some of the common features of ALD progression in ASH (alcoholic steatohepatitis) and NAFLD to NASH (non-alcoholic steatohepatitis). Hepatic steatosis, followed by fibrosis, lead to a continuous progression accompanied by angiogenesis. This process creates hypoxia, which activates vascular factors, initiating pathological angiogenesis and further fibrosis. This forms a vicious cycle of ongoing damage and progression. This condition further exacerbates liver injury and may contribute to the development of comorbidities, such as metabolic syndrome as well as hepatocellular carcinoma. Increasing evidence suggests that anti-angiogenic therapy may have beneficial effects on these hepatic disorders and their exacerbation. Therefore, there is a great interest to deepen the knowledge of the molecular mechanisms of natural anti-angiogenic products that could both prevent and control liver diseases. In this review, we focus on the role of major natural anti-angiogenic compounds against steatohepatitis and determine their potential therapeutic benefits in the treatment of liver inflammation caused by an imbalanced diet.

Diets, Gut Microbiota and Metabolites

The gut microbiota refers to the gross collection of microorganisms, estimated trillions of them, which reside within the gut and play crucial roles in the absorption and digestion of dietary nutrients. In the past decades, the new generation 'omics' (metagenomics, transcriptomics, proteomics, and metabolomics) technologies made it possible to precisely identify microbiota and metabolites and describe their variability between individuals, populations and even different time points within the same subjects. With massive efforts made, it is now generally accepted that the gut microbiota is a dynamically changing population, whose composition is influenced by the hosts' health conditions and lifestyles. Diet is one of the major contributors to shaping the gut microbiota. The components in the diets vary in different countries, religions, and populations. Some special diets have been adopted by people for hundreds of years aiming for better health, while the underlying mechanisms remain largely unknown. Recent studies based on volunteers or diet-treated animals demonstrated that diets can greatly and rapidly change the gut microbiota. The unique pattern of the nutrients from the diets and their metabolites produced by the gut microbiota has been linked with the occurrence of diseases, including obesity, diabetes, nonalcoholic fatty liver disease, cardiovascular disease, neural diseases, and more. This review will summarize the recent progress and current understanding of the effects of different dietary patterns on the composition of gut microbiota, bacterial metabolites, and their effects on the host's metabolism.

The Janus-Faced Role of Lipid Droplets in Aging: Insights from the Cellular Perspective

It is widely accepted that nine hallmarks-including mitochondrial dysfunction, epigenetic alterations, and loss of proteostasis-exist that describe the cellular aging process. Adding to this, a well-described cell organelle in the metabolic context, namely, lipid droplets, also accumulates with increasing age, which can be regarded as a further aging-associated process. Independently of their essential role as fat stores, lipid droplets are also able to control cell integrity by mitigating lipotoxic and proteotoxic insults. As we will show in this review, numerous longevity interventions (such as mTOR inhibition) also lead to strong accumulation of lipid droplets in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mammalian cells, just to name a few examples. In mammals, due to the variety of different cell types and tissues, the role of lipid droplets during the aging process is much more complex. Using selected diseases associated with aging, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and cardiovascular disease, we show that lipid droplets are "Janus"-faced. In an early phase of the disease, lipid droplets mitigate the toxicity of lipid peroxidation and protein aggregates, but in a later phase of the disease, a strong accumulation of lipid droplets can cause problems for cells and tissues.

Therapeutic mechanisms of the medicine and food homology formula Xiao-Ke-Yin on glucolipid metabolic dysfunction revealed by transcriptomics, metabolomics and microbiomics in mice

BACKGROUND

In recent decades, the prevalence of metabolic diseases, particularly diabetes, hyperlipidemia, obesity, and non-alcoholic fatty liver disease (NAFLD), has increased dramatically, causing great public health and economic burdens worldwide. Traditional Chinese medicine (TCM) serves as an effective therapeutic choice. Xiao-Ke-Yin (XKY) is a medicine and food homology TCM formula consisting of nine "medicine and food homology" herbs and is used to ameliorate metabolic diseases, such as insulin resistance, diabetes, hyperlipidemia and NAFLD. However, despite its therapeutic potential in metabolic disorders, the underlying mechanisms of this TCM remain unclear. This study aimed to evaluate the therapeutic effectiveness of XKY on glucolipid metabolism dysfunction and explore the potential mechanisms in db/db mice.

METHODS

To verify the effects of XKY, db/db mice were treated with different concentrations of XKY (5.2, 2.6 and 1.3 g/kg/d) and metformin (0.2 g/kg/d, a hypoglycemic positive control) for 6 weeks, respectively. During this study, we detected the body weight (BW) and fasting blood glucose (FBG), oral glucose tolerance test (OGTT), insulin tolerance test (ITT), daily food intake and water intake. At the end of the animal experiment, blood samples, feces, liver and intestinal tissue of mice in all groups were collected. The potential mechanisms were investigated by using hepatic RNA sequencing, 16 S rRNA sequencing of the gut microbiota and metabolomics analysis.

RESULTS

XKY efficiently mitigated hyperglycemia, IR, hyperlipidemia, inflammation and hepatic pathological injury in a dose dependent manner. Mechanistically, hepatic transcriptomic analysis showed that XKY treatment significantly reversed the upregulated cholesterol biosynthesis which was further confirmed by RT-qPCR. Additionally, XKY administration maintained intestinal epithelial homeostasis, modulated gut microbiota dysbiosis, and regulated its metabolites. In particular, XKY decreased secondary bile acid producing bacteria (Clostridia and Lachnospircaeae) and lowered fecal secondary bile acid (lithocholic acid (LCA) and deoxycholic acid (DCA)) levels to promote hepatic bile acid synthesis by inhibiting the LCA/DCA-FXR-FGF15 signalling pathway. Furthermore, XKY regulated amino acid metabolism including arginine biosynthesis, alanine, aspartate and glutamate metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and tryptophan metabolism likely by increasing Bacilli, Lactobacillaceae and Lactobacillus, and decreasing Clostridia, Lachnospircaeae, Tannerellaceae and Parabacteroides abundances.

CONCLUSION

Taken together, our findings demonstrate that XKY is a promising "medicine food homology" formula for ameliorating glucolipid metabolism and reveal that the therapeutic effects of XKY may due to its downregulation of hepatic cholesterol biosynthesis and modulation of the dysbiosis of the gut microbiota and metabolites.

Semaglutide Has Beneficial Effects on Non-Alcoholic Steatohepatitis in Ldlr-/-.Leiden Mice

Semaglutide, a glucagon-like peptide-1 receptor agonist, is an antidiabetic medication that has recently been approved for the treatment of obesity as well. Semaglutide is postulated to be a promising candidate for the treatment of non-alcoholic steatohepatitis (NASH). Here, Ldlr-/-.Leiden mice received a fast-food diet (FFD) for 25 weeks, followed by another 12 weeks on FFD with daily subcutaneous injections of semaglutide or vehicle (control). Plasma parameters were evaluated, livers and hearts were examined, and hepatic transcriptome analysis was performed. In the liver, semaglutide significantly reduced macrovesicular steatosis (-74%, p < 0.001) and inflammation (-73%, p < 0.001) and completely abolished microvesicular steatosis (-100%, p < 0.001). Histological and biochemical assessment of hepatic fibrosis showed no significant effects of semaglutide. However, digital pathology revealed significant improvements in the degree of collagen fiber reticulation (-12%, p < 0.001). Semaglutide did not affect atherosclerosis relative to controls. Additionally, we compared the transcriptome profile of FFD-fed Ldlr-/-.Leiden mice with a human gene set that differentiates human NASH patients with severe fibrosis from those with mild fibrosis. In FFD-fed Ldlr-/-.Leiden control mice, this gene set was upregulated as well, while semaglutide predominantly reversed this gene expression. Using a translational model with advanced NASH, we demonstrated that semaglutide is a promising candidate with particular potential for the treatment of hepatic steatosis and inflammation, while for the reversal of advanced fibrosis, combinations with other NASH agents may be necessary.

Automated Segmentation and Morphological Characterization of Hepatic Steatosis and Correlation with Histopathology

BACKGROUND/OBJECTIVES

Prevalence of nonalcoholic fatty liver disease (NAFLD) has increased to 25% of the world population. Hepatic steatosis is a hallmark feature of NAFLD and is assessed histologically using visual and ordinal fat grading criteria (0-3) from the Nonalcoholic Steatohepatitis (NASH) Clinical Research Network (CRN) scoring system. The purpose of this study is to automatically segment and extract morphological characteristics and distributions of fat droplets (FDs) on liver histology images and find associations with severity of steatosis.

METHODS

A previously published human cohort of 68 NASH candidates was graded for steatosis by an experienced pathologist using the Fat CRN grading system. The automated segmentation algorithm quantified fat fraction (FF) and fat-affected hepatocyte ratio (FHR), extracted fat morphology by calculating radius and circularity of FDs, and examined FDs distribution and heterogeneity using nearest neighbor distance and regional isotropy.

RESULTS

Regression analysis and Spearman correlation (ρ) yielded high correlations for radius (R2 = 0.86, ρ = 0.72), nearest neighbor distance (R2 = 0.82, ρ = -0.82), regional isotropy (R2 = 0.84, ρ = 0.74), and FHR (R2 = 0.90, ρ = 0.85), and low correlation for circularity (R2 = 0.48, ρ = -0.32) with FF and pathologist grades, respectively. FHR showed a better distinction between pathologist Fat CRN grades compared to conventional FF measurements, making it a potential surrogate measure for Fat CRN scores. Our results showed variation in distribution of morphological features and steatosis heterogeneity within the same patient's biopsy sample as well as between patients of similar FF.

CONCLUSIONS

The fat percentage measurements, specific morphological characteristics, and patterns of distribution quantified with the automated segmentation algorithm showed associations with steatosis severity; however, future studies are warranted to evaluate the clinical significance of these steatosis features in progression of NAFLD and NASH.

Atorvastatin Attenuates Diet-Induced Non-Alcoholic Steatohepatitis in APOE*3-Leiden Mice by Reducing Hepatic Inflammation

Patients with metabolic syndrome are often prescribed statins to prevent the development of cardiovascular disease. Conversely, data on their effects on non-alcoholic steatohepatitis (NASH) are lacking. We evaluated these effects by feeding APOE*3-Leiden mice a Western-type diet (WTD) with or without atorvastatin to induce NASH and hepatic fibrosis. Besides the well-known plasma cholesterol lowering (-30%) and anti-atherogenic effects (severe lesion size -48%), atorvastatin significantly reduced hepatic steatosis (-22%), the number of aggregated inflammatory cells in the liver (-80%) and hepatic fibrosis (-92%) compared to WTD-fed mice. Furthermore, atorvastatin-treated mice showed less immunohistochemically stained areas of inflammation markers. Atorvastatin prevented accumulation of free cholesterol in the form of cholesterol crystals (-78%). Cholesterol crystals are potent inducers of the NLRP3 inflammasome pathway and atorvastatin prevented its activation, which resulted in reduced expression of the pro-inflammatory cytokines interleukin (IL)-1β (-61%) and IL-18 (-26%). Transcriptome analysis confirmed strong reducing effects of atorvastatin on inflammatory mediators, including NLRP3, NFκB and TLR4. The present study demonstrates that atorvastatin reduces hepatic steatosis, inflammation and fibrosis and prevents cholesterol crystal formation, thereby precluding NLRP3 inflammasome activation. This may render atorvastatin treatment as an attractive approach to reduce NAFLD and prevent progression into NASH in dyslipidemic patients.

Innate Immune System in the Pathogenesis of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a prevalent condition characterized by lipid accumulation in hepatocytes with low alcohol consumption. The development of sterile inflammation, which occurs in response to a range of cellular stressors or injuries, has been identified as a major contributor to the pathogenesis of NAFLD. Recent studies of the pathogenesis of NAFLD reported the newly developed roles of damage-associated molecular patterns (DAMPs). These molecules activate pattern recognition receptors (PRRs), which are placed in the infiltrated neutrophils, dendritic cells, monocytes, or Kupffer cells. DAMPs cause the activation of PRRs, which triggers a number of immunological responses, including the generation of cytokines that promote inflammation and the localization of immune cells to the site of the damage. This review provides a comprehensive overview of the impact of DAMPs and PRRs on the development of NAFLD.

Low-Dose Acetylsalicylic Acid and Mitochondria-Targeted Antioxidant Mitoquinone Attenuate Non-Alcoholic Steatohepatitis in Mice

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. NAFLD can evolve from simple fatty liver to non-alcoholic steatohepatitis (NASH), and ultimately, to cirrhosis. Inflammation and oxidative stress, promoted by mitochondrial dysfunction, play a crucial role in the onset and development of NASH. To date, no therapy has been approved for NAFLD and NASH. The aim of this study is to evaluate if the anti-inflammatory activity of acetylsalicylic acid (ASA) and the mitochondria-targeted antioxidant effect of mitoquinone could hinder the progression of non-alcoholic steatohepatitis. In mice, fatty liver was induced through the administration of a deficient in methionine and choline and rich in fat diet. Two experimental groups were treated orally with ASA or mitoquinone. Histopathologic evaluation of steatosis and inflammation was performed; the hepatic expression of genes associated with inflammation, oxidative stress, and fibrosis was evaluated; the protein expression of IL-10, cyclooxygenase 2, superoxide dismutase 1, and glutathione peroxidase 1 in the liver was analyzed; a quantitative analysis of 15-epi-lipoxin A4 in liver homogenates was performed. Mitoquinone and ASA significantly reduced liver steatosis and inflammation by decreasing the expression of TNFα, IL-6, Serpinb3, and cyclooxygenase 1 and 2 and restoring the anti-inflammatory IL-10. Treatment with mitoquinone and ASA increased the gene and protein expression of antioxidants, i.e., catalase, superoxide dismutase 1, and glutathione peroxidase 1, and decreased the expression of profibrogenic genes. ASA normalized the levels of 15-epi-Lipoxin A4. In mice fed with a deficient in methionine and choline and rich in fat diet, mitoquinone and ASA reduce steatosis and necroinflammation and may represent two effective novel strategies for the treatment of non-alcoholic steatohepatitis.

From Non-Alcoholic Fatty Liver to Hepatocellular Carcinoma: A Story of (Mal)Adapted Mitochondria

Non-alcoholic fatty liver disease (NAFLD) is a global pandemic affecting 25% of the world's population and is a serious health and economic concern worldwide. NAFLD is mainly the result of unhealthy dietary habits combined with sedentary lifestyle, although some genetic contributions to NAFLD have been documented. NAFLD is characterized by the excessive accumulation of triglycerides (TGs) in hepatocytes and encompasses a spectrum of chronic liver abnormalities, ranging from simple steatosis (NAFL) to steatohepatitis (NASH), significant liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although the molecular mechanisms that cause the progression of steatosis to severe liver damage are not fully understood, metabolic-dysfunction-associated fatty liver disease is strong evidence that mitochondrial dysfunction plays a significant role in the development and progression of NAFLD. Mitochondria are highly dynamic organelles that undergo functional and structural adaptations to meet the metabolic requirements of the cell. Alterations in nutrient availability or cellular energy needs can modify mitochondria formation through biogenesis or the opposite processes of fission and fusion and fragmentation. In NAFL, simple steatosis can be seen as an adaptive response to storing lipotoxic free fatty acids (FFAs) as inert TGs due to chronic perturbation in lipid metabolism and lipotoxic insults. However, when liver hepatocytes' adaptive mechanisms are overburdened, lipotoxicity occurs, contributing to reactive oxygen species (ROS) formation, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress. Impaired mitochondrial fatty acid oxidation, reduction in mitochondrial quality, and disrupted mitochondrial function are associated with a decrease in the energy levels and impaired redox balance and negatively affect mitochondria hepatocyte tolerance towards damaging hits. However, the sequence of events underlying mitochondrial failure from steatosis to hepatocarcinoma is still yet to be fully clarified. This review provides an overview of our understanding of mitochondrial adaptation in initial NAFLD stages and highlights how hepatic mitochondrial dysfunction and heterogeneity contribute to disease pathophysiology progression, from steatosis to hepatocellular carcinoma. Improving our understanding of different aspects of hepatocytes' mitochondrial physiology in the context of disease development and progression is crucial to improving diagnosis, management, and therapy of NAFLD/NASH.

The role of ChREBP in carbohydrate sensing and NAFLD development

Excessive sugar consumption and defective glucose sensing by hepatocytes contribute to the development of metabolic diseases including type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD). Hepatic metabolism of carbohydrates into lipids is largely dependent on the carbohydrate-responsive element binding protein (ChREBP), a transcription factor that senses intracellular carbohydrates and activates many different target genes, through the activation of de novo lipogenesis (DNL). This process is crucial for the storage of energy as triglycerides in hepatocytes. Furthermore, ChREBP and its downstream targets represent promising targets for the development of therapies for the treatment of NAFLD and T2DM. Although lipogenic inhibitors (for example, inhibitors of fatty acid synthase, acetyl-CoA carboxylase or ATP citrate lyase) are currently under investigation, targeting lipogenesis remains a topic of discussion for NAFLD treatment. In this Review, we discuss mechanisms that regulate ChREBP activity in a tissue-specific manner and their respective roles in controlling DNL and beyond. We also provide in-depth discussion of the roles of ChREBP in the onset and progression of NAFLD and consider emerging targets for NAFLD therapeutics.

Circulating Short-Chain Fatty Acids and Non-Alcoholic Fatty Liver Disease Severity in Patients with Type 2 Diabetes Mellitus

(1) Background: Non-alcoholic fatty liver disease (NAFLD) is a major global health concern. The increasing prevalence of NAFLD has been related to type 2 diabetes mellitus (T2D). However, the relationship between short-chain fatty acids (SCFAs) and NAFLD severity is ambiguous in T2D subjects. This study aimed to explore the association of SCFAs with the severity of NAFLD in T2D patients. (2) Methods: We employed echography to examine the severity of hepatic steatosis. The serum levels of nine SCFAs, namely, formate, acetate, propionate, butyrate, isobutyrate, methylbutyrate, valerate, isovalerate, and methylvalerate, were measured using gas chromatography mass spectrometry. (3) Results: A total of 259 T2D patients was enrolled in this cross-sectional study. Of these participants, 117 with moderate to severe NAFLD had lower levels of formate, isobutyrate, and methylbutyrate than the 142 without NAFLD or with mild NAFLD. Lower circulating levels of isobutyrate and methylbutyrate were associated with an increased severity of NAFLD. A relationship between NAFLD severity and circulating isobutyrate and methylbutyrate levels was found independently of a glycated hemoglobin (HbA1C) level of 7.0%. (4) Conclusion: Circulating levels of isobutyrate and methylbutyrate were significantly and negatively correlated with NAFLD severity in the enrolled T2D patients. SCFAs may be related to NAFLD severity in T2D patients.

Risk Factors of Non-alcoholic Fatty Liver Disease in the Iranian Adult Population: A Systematic Review and Meta-analysis

Context: Non-alcoholic fatty liver disease (NAFLD) is progressing considerably worldwide. Identifying the risk factors of NAFLD is a critical step in preventing its progression. Methods: In November 2022, two independent researchers studied seven databases, including PubMed, ISI/WoS, ProQuest, Scopus, SID, Magiran, and Google Scholar, and reference list of relevant articles, searching studies that assessed NAFLD risk factors in the Iranian adult population. Heterogeneity between studies was assessed by Cochran’s test and its composition using I2 statistics. A random-effects model was used when heterogeneity was observed; otherwise, a fixed-effects model was applied. Egger’s regression test and Trim-and-Fill analysis were used to assess publication bias. Comprehensive Meta-analysis software (version 3) was used for the analyses of the present study. Results: The results of this study showed significant associations between NAFLD with age (n = 15, odds ratio (OR) = 2.12, 95% CI: 1.79 - 2.51), body mass index (n = 46, OR = 5.00, 95% CI: 3.34 - 7.49), waist circumference (n = 20, OR = 6.37, 95% CI: 3.25 - 12.48), waist-to-hip ratio (n = 17, OR = 4.72, 95% CI: 3.93 - 5.66), total cholesterol (n = 39, OR = 1.80, 95% CI: 1.52 - 2.13), high-density lipoprotein (n = 37, OR = 0.53, 95% CI: 0.44 - 0.65), low-density lipoprotein (n = 31, OR = 1.68, 95% CI: 1.38 - 2.05), triglyceride (n = 31, OR = 3.21, 95% CI: 2.67 - 3.87), alanine aminotransferase (n = 26, OR = 4.06, 95% CI: 2.94 - 5.62), aspartate aminotransferase (n = 27, OR = 2.16, 95% CI: 1.50 - 3.12), hypertension (n = 13, OR = 2.53, 95% CI: 2.32 - 2.77), systolic blood pressure (n = 13, OR = 1.83, 95% CI: 1.53 - 2.18), diastolic blood pressure (n = 14, OR = 1.80, 95% CI: 1.48 - 2.20), fasting blood sugar (n = 31, OR = 2.91, 95% CI: 2.11- 4.01), homeostatic model assessment for insulin resistance (n = 5, OR = 1.92, 95% CI: 1.48 - 2.59), diabetes mellitus (n = 15, OR = 3.04, 95% CI: 2.46 - 3.75), metabolic syndrome (n = 10, OR = 3.56, 95% CI: 2.79 - 4.55), and physical activity (n = 11, OR = 0.32, 95% CI: 0.24 - 0.43) (P < 0.05). Conclusions: In conclusion, several factors are significantly associated with NAFLD. However, anthropometric indices had the strongest relationship with NAFLD in the Iranian adult population.