Prevalence and incidence of MAFLD and associated anthropometric parameters among prepubertal children of the Shanghai Birth Cohort.

BACKGROUND AND AIM: Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease in adolescent and adult population. However, the epidemiologic data of MAFLD in prepubertal children remain limited. This study aimed to investigate the prevalence and incidence of MAFLD and assess the role of anthropometric parameters in identifying and predicting MAFLD in this population. METHODS: Children from the Shanghai Birth Cohort Study who underwent an 8-year follow-up with anthropometric measurements and transient elastography FibroScan-502 examination (M probe, Echosens, Paris, France) were enrolled. Some of them also completed a 5-year follow-up. Diagnosis of fatty liver disease (FLD) was based on the controlled attenuation parameter (CAP) value exceeding 248 dB/m, and MAFLD was defined as FLD combined with obesity or central obesity. Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic accuracy of anthropometric parameters for MAFLD. RESULTS: A total of 848 children (431 boys) from the Shanghai Birth Cohort Study were followed up for 8 years, and among them, 385 children (189 boys) also participated in the 5-year follow-up. The prevalence of FLD and MAFLD at 5 years old was 3.90% and 0.52%, respectively, while at 8 years old, the prevalence rates increased to 5.07% for FLD and 3.42% for MAFLD. The 8-year-old children with MAFLD exhibited significantly higher weight, body mass index (BMI), chest circumference, waist circumference, hip circumference, waist-to-height ratio, waist-to-hip ratio, and liver stiffness measurement compared to those without MAFLD (all p < 0.05). The incidence rates of FLD and MAFLD at 8 years old, considering the 5-year follow-up data, were 3.78% (14/370) and 3.13% (12/383), respectively. Obese or centrally obese children at 5 years old had a higher incidence of FLD and MAFLD at the 8-year follow-up. Waist circumference and BMI showed significant associations with the presence and incidence of MAFLD, respectively, with the largest AUC values in ROC curve analysis. In addition, chest circumference was significantly associated with MAFLD in obese children. CONCLUSION: This study provides insights into the incidence and prevalence of MAFLD in prepubertal children. It underscores the importance of anthropometric parameters in identifying and predicting MAFLD in this population. Further research encompassing a broader age range and incorporating these indicators and additional metabolic markers is necessary to enhance the understanding and management of MAFLD in children.

Limited role for hyperammonemia in the progression of diet-induced nonalcoholic steatohepatitis.

OBJECTIVES: To determine whether hyperammonemia has a direct impact on steatohepatitis in mice fed with a high-fat diet (HFD). METHODS: Male C57BL/6 mice were divided into two groups receiving either chow diet or HFD. After 12-week NASH modeling, hyperammonemia was induced by intragastric administration of ammonium chloride solution (NH4 Cl) or liver-specific carbamoyl phosphate synthetase 1 (Cps1) knockdown. In vitro experiments were performed in HepG2 cells induced by free fatty acid (FFA) and NH4 Cl. RESULTS: NH4 Cl administration led to increased levels of plasma and hepatic ammonia in NASH mice. NH4 Cl-induced hyperammonemia did not influence liver histological changes in mice fed with HFD; however, elevated plasma cholesterol level, and an increasing trend of liver lipid content were observed. No significant effect of hyperammonemia on hepatic inflammation and fibrosis in NASH mice was found. In vitro cell experiments showed that NH4 Cl treatment failed to increase the lipid droplet content and the expressions of de novo lipogenesis genes in HepG2 cells induced by FFA. The knockdown of Cps1 in HFD-fed mice resulted in elevated plasma ammonia levels but did not cause histological change in the liver. CONCLUSIONS: Our study revealed a limited role of ammonia in aggravating the progression of NASH. Further studies are needed to clarify the role and mechanism of ammonia in NASH development.

Premorbid Steatohepatitis Increases the Seriousness of Dextran Sulfate Sodium-induced Ulcerative Colitis in Mice.

Background and Aims: The concurrence of nonalcoholic steatohepatitis (NASH) and ulcerative colitis (UC) is increasingly seen in clinical practice, but the underlying mechanisms remain unclear. This study aimed to develop a mouse model of the phenomenon by combining high-fat high-cholesterol diet (HFHCD)-induced NASH and dextran sulfate sodium (DSS)-induced UC, that would support mechanistic studies. Methods: Male C57BL/6 mice were randomly assigned to two groups receiving either a chow diet or HFHCD for 12 weeks of NASH modeling. The mice were the divided into four subgroups for UC modeling: (1) A control group given a chow diet with normal drinking water; (2) A colitis group given chow diet with 2% DSS in drinking water; (3) A steatohepatitis group given HFHCD with normal drinking water; and (4) A steatohepatitis + colitis group given HFHCD with 2% DSS in drinking water. Results: NASH plus UC had high mortality (58.3%). Neither NASH nor UC alone were fatal. Although DSS-induced colitis did not exacerbate histological liver injury in HFHCD-fed mice, premorbid NASH significantly increased UC-related gut injury compared with UC alone. It was characterized by a significantly shorter colon, more colonic congestion, and a higher histopathological score (p<0.05). Inflammatory (tumor necrosis factor-alpha, interleukin 1 beta, C-C motif chemokine ligand 2, and nuclear factor kappa B) and apoptotic (Bcl2, Bad, Bim, and Bax) signaling pathways were significantly altered in distal colon tissues collected from mice with steatohepatitis + colitis compared with the other experimental groups. Conclusions: Premorbid steatohepatitis significantly aggravated DSS-induced colitis and brought about a lethal phenotype. Potential links between NASH and UC pathogeneses can be investigated using this model.

Association of maternal obesity and gestational diabetes mellitus with overweight/obesity and fatty liver risk in offspring.

BACKGROUND: Childhood obesity and fatty liver are associated with adverse outcomes such as diabetes, metabolic syndrome, and cardiovascular diseases in adulthood. It is very important to identify relevant risk factors and intervene as early as possible. At present, the relationship between maternal and offspring metabolic factors is conflicting. AIM: To estimate the association of maternal obesity and gestational diabetes mellitus (GDM) with overweight/obesity and fatty liver risk in offspring at 8 years of age. METHODS: The prospective study included mothers who all had a 75-g oral glucose tolerance test at 24-28 wk of gestation and whose offspring completed follow-up at 8 years of age. Offspring birth weight, sex, height, weight, and body mass index (BMI) were measured and calculated. FibroScan-502 examination with an M probe (Echosens, Paris, France) was prospectively conducted in offspring aged 8 years from the Shanghai Prenatal Cohort Study. RESULTS: A total of 430 mother-child pairs were included in the analysis. A total of 62 (14.2%) mothers were classified as obese, and 48 (11.1%) were classified as having GDM. The mean age of the offspring at follow-up was 8 years old. Thirty-seven (8.6%) offspring were overweight, 14 (3.3%) had obesity, and 60 (14.0%) had fatty liver. The prevalence of overweight, obesity and fatty liver in offspring increased significantly across maternal BMI quartiles (all P < 0.05). Among offspring of mothers with GDM, 12 (25.0%) were overweight, 4 (8.3%) were obese, and 12 (25.0%) had fatty liver vs. 25 (6.5%), 10 (2.6%) and 48 (12.6%), respectively, for offspring of mothers without GDM (all P < 0.05). In multiple logistic regression, after adjustment for variables, the OR for fatty liver in offspring was 8.26 (95%CI: 2.38-28.75) for maternal obesity and GDM. CONCLUSION: This study showed that maternal obesity can increase the odds of overweight/obesity and fatty liver in offspring, and GDM status also increases the odds of overweight/obesity in offspring. Weight management and glycemic control before and during pregnancy need to be highlighted in primary prevention of pediatric obesity and fatty liver.

Ammonia Scavenger Restores Liver and Muscle Injury in a Mouse Model of Non-alcoholic Steatohepatitis With Sarcopenic Obesity.

Recent studies have revealed that sarcopenia is closely associated with obesity and non-alcoholic steatohepatitis (NASH). However, few attempted to explore the cause-and-effect relationship between sarcopenic obesity and NASH. In this study, we investigated muscular alterations in a rodent NASH model to elucidate their intrinsic relations and explore the potential therapeutic target. Forty-six 8-week-old and twenty 42-week-old male C57BL/6 mice (defined as young and middle-aged mice, respectively) were fed with a high-fat diet (HFD) for 12 or 20 weeks. A subset of young mice was subjected to ammonia lowering treatment by L-ornithine L-aspartate (LOLA). We examined body composition and muscle strength by nuclear magnetic resonance and grip strength meter, respectively. At the end of the 12th week, all HFD-fed mice developed typical steatohepatitis. Meanwhile, sarcopenia occurred in HFD-fed middle-aged mice, whereas young mice only demonstrated decreased grip strength. Until the end of week 20, young mice in the HFD group exhibited significant sarcopenia and obesity phenotypes, including decreased lean body mass and grip strength, and increased body fat mass and percentage body fat. Additionally, plasma ammonia level was markedly increased in HFD-fed mice of both ages at week 20. Plasma ammonia level was negatively associated with muscle strength and myofiber diameter in young mice. LOLA can significantly reduce plasma levels of ammonia, alanine aminotransaminase, aspartate aminotransaminase, and cholesterol in mice fed an HFD. Hepatic infiltration of inflammatory cells and collagen deposition area were significantly decreased in HFD group by LOLA treatment. Meanwhile, LOLA significantly increased lean body mass, grip strength, and average muscle fiber diameter of HFD-fed mice. These findings suggest that the occurrence of NASH precedes sarcopenia in HFD mice, and the steatohepatitis-related hyperammonemia might contribute to the pathogenesis of sarcopenia. LOLA might be an effective drug for both steatohepatitis and sarcopenic obesity.

Prevalence and characteristics of MAFLD in Chinese adults aged 40 years or older: A community-based study.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) was recently proposed to be renamed metabolic dysfunction-associated fatty liver disease (MAFLD) with the diagnostic criteria revised. We investigated the similarities and differences in the prevalence and clinical characteristics of MAFLD and NAFLD in Chinese adults. METHODS: A cross-sectional study of 9980 Chinese individuals aged 40 years or older was performed between 2011 and 2012 using randomized, stratified cluster sampling in Shanghai, China. A detailed questionnaire and the results of abdominal ultrasonography, a standardized 2-h 75-g oral glucose tolerance test and blood biochemical examinations were collected. RESULTS: A total of 9927 subjects were included in this study. The prevalence of MAFLD (40.3%) was significantly higher than that of NAFLD (36.9%) (P < 0.05). MAFLD was highly prevalent in type 2 diabetes mellitus (T2DM) (53.8%), impaired fasting glucose (35.7%) and impaired glucose tolerance (40.9%). High risk of advanced fibrosis based on fibrosis-4 was highly prevalent (14.7%) in lean MAFLD with T2DM. Among 9927 subjects, 3481 (35.1%) fulfilled the diagnostic criteria for MAFLD and NAFLD (MAFLD+NAFLD+), 521 (5.2%) MAFLD+NAFLD-, and 181 (1.8%) MAFLD-NAFLD+. The MAFLD+NAFLD- group had more significant metabolic disorders than those in the MAFLD+NAFLD+ group (all P < 0.05). Among MAFLD-NAFLD+ subjects, 82.9% had metabolic disorders. CONCLUSIONS: The new definition of MAFLD may better reflect the pathogenesis related to metabolism. Future research should focus on studying the natural history, pathogenesis and treatment effectivity of the overlap and non-overlap of NAFLD and MAFLD subjects.

The burden and sexual dimorphism with nonalcoholic fatty liver disease in Asian children: A systematic review and meta-analysis.

BACKGROUND: Despite substantial attention paid to the epidemic of nonalcoholic fatty liver disease (NAFLD) in adults, data on the burden and sexual dimorphism of NAFLD in Asian children have not yet been synthesized. METHODS: We conducted a literature search of 735 references up to April 2021. Pooled analyses, stratified analyses and meta-regression were all performed. RESULTS: Thirty-three study populations were finally included. Nine of them comprising 20 595 children showed an overall NAFLD prevalence of 5.53% (95% CI 3.46%-8.72%), in which, 36.64% (95% CI, 27.99%-46.26%) NAFLD subjects had elevated levels of ALT. The prevalence rate of NAFLD increased about 1.6-fold from 2004 to 2010 to the last decade. Male predominant trends were observed in paediatric NAFLD (boys: 8.18%, 95% CI 4.93%-13.26%; girls: 3.60%, 95% CI 1.60%-7.87%). Moreover, meta-analysis showed that after 10 years of age, boys were more prone to have NAFLD than girls (OR = 1.75; P = .0012). In addition, the pooled prevalence of NAFLD increased sequentially in normal-weight (1.49%, 95% CI 0.88%-2.51%, n = 2610), overweight (16.72%, 95% CI 7.07%-34.65%, n = 1265) and obese children (50.13%, 95% CI 41.99%-58.27%, n = 6434 individuals). After full covariate adjustment, the multivariate meta-regression also showed that boy percentage (P = .0396) and body mass index (P < .0001) were positively correlated with prevalent NAFLD. CONCLUSIONS: In Asia, paediatric NAFLD is becoming prevalent over the recent decades, particularly among obese children and boys after 10 years old. The hormonal and chromosomal origins of paediatric NAFLD dimorphism need further investigation.

Metabolic Disorders Combined with Noninvasive Tests to Screen Advanced Fibrosis in Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease (NAFLD) is associated with metabolic disorders. This study aimed to explore the role of metabolic disorders in screening advanced fibrosis in NAFLD patients. METHODS: A total of 246 histologically-proven NAFLD patients were enrolled across 14 centers. We compared the severity of fibrosis in patients with different components of metabolic disorders. Based on standard noninvasive tests and metabolic disorders, we developed new algorithms to identify advanced fibrosis. RESULTS: Metabolic syndrome (MetS) was frequent in NAFLD patients (133/246, 54%). Patients with MetS had a higher proportion of significant fibrosis (p=0.014) and higher LSM values (9.2 kPa, vs. 7.4 kPa, p=0.002) than those without MetS. Patients with more metabolic disorders had higher fibrosis stages (p=0.017). Reduced high-density lipoprotein cholesterol (odds ratio [OR]: 2.241, 95% confidence interval [CI]: 1.004-5.002, p=0.049) and raised fasting glucose (OR: 4.500, 95% CI: 2.083-9.725, p<0.001) were significantly associated with advanced fibrosis. Using these two metabolic disorders as a screening tool, a sensitivity, specificity and accuracy of 92%, 81% and 83% was achieved, respectively. With the new algorithms combining metabolic disorders with noninvasive measurements, the number of patients requiring liver biopsy was reduced, especially in combination with the Fibrosis-4 score and metabolic disorders (36% to 17%, p<0.001). In addition, this stepwise algorithm could achieve a high accuracy (85%) and high negative predictive value (93%). CONCLUSIONS: Metabolic disorders should be taken into consideration in the diagnosis of advanced fibrosis. With further validation and investigation, new algorithms could be recommended in primary care units to spare patients from unnecessary referral and liver biopsies.

Efficacy of Intragastric Balloons in the Markers of Metabolic Dysfunction-associated Fatty Liver Disease: Results from Meta-analyses.

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease, now renamed metabolic dysfunction-associated fatty liver disease (MAFLD), is common in obese patients. Intragastric balloon (IGB), an obesity management tool with low complication risk, might be used in MAFLD treatment but there is still unexplained heterogeneity in results across studies. METHODS: We conducted a systematic search of 152 citations published up to September 2020. Meta-analyses, stratified analyses, and meta-regression were performed to evaluate the efficacy of IGB on homeostasis model assessment of insulin resistance (HOMA-IR), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT), and to identify patients most appropriate for IGB therapy. RESULTS: Thirteen observational studies and one randomized controlled trial met the inclusion criteria (624 participants in total). In the overall estimate, IGB therapy significantly improved the serum markers change from baseline to follow-up [HOMA-IR: 1.56, 95% confidence interval (CI)=1.16-1.95; ALT: 11.53 U/L, 95% CI=7.10-15.96; AST: 6.79 U/L, 95% CI=1.69-11.90; GGT: 10.54 U/L, 95% CI=6.32-14.75]. In the stratified analysis, there were trends among participants with advanced age having less change in HOMA-IR (1.07 vs. 1.82). The improvement of insulin resistance and liver biochemistries with swallowable IGB therapy was no worse than that with endoscopic IGB. Multivariate meta-regression analyses showed that greater HOMA-IR loss was predicted by younger age (p=0.0107). Furthermore, effectiveness on ALT and GGT was predicted by basal ALT (p=0.0004) and GGT (p=0.0026), respectively. CONCLUSIONS: IGB is effective among the serum markers of MAFLD. Younger patients had a greater decrease of HOMA-IR after IGB therapy.

The pathologic relevance of metabolic criteria in patients with biopsy-proven nonalcoholic fatty liver disease and metabolic dysfunction associated fatty liver disease: A multicenter cross-sectional study in China.

BACKGROUND: This study aimed to assess the association between metabolic syndrome (MetS) and severity of nonalcoholic fatty liver disease (NAFLD), and to discuss the pathological relevance of the diagnostic criteria in metabolic (dysfunction) associated fatty liver disease (MAFLD). METHODS: This was a multicenter, cross-sectional study. Patients with NAFLD confirmed by liver biopsy were enrolled between July 2016 and December 2018 from 14 centers across the mainland of China. Anthropometric and metabolic parameters were collected to assess the pathological relevance. RESULTS: Of 246 enrolled patients with NAFLD, 150 (61.0%) had the comorbidity of MetS. With the increase of metabolic components, the proportions of nonalcoholic steatohepatitis (NASH) and significant fibrosis were notably increased. The comorbid three metabolic components significantly increased the proportion of NASH, and further increase of metabolic components did not increase the proportion of NASH. However, the increase of metabolic components was parallel to the increase of the proportion of liver fibrosis. Among the 246 patients, 239 (97.2%) met the diagnostic criteria of MAFLD. Although non-MAFLD patients had less NASH, they present with similar proportion of significant fibrosis and cirrhosis. In the diagnostic criteria of MAFLD, BMI ≥ 23 kg/m2 was related to NASH (Mantel-Haenszel Common Estimate OR: 2.975; 95% CI: 1.037-8.538; P = 0.043), and T2DM was related to significant fibrosis (Mantel-Haenszel Common Estimate OR: 2.531; 95% CI: 1.388-4.613; P = 0.002). The homeostasis model assessment of insulin resistance (HOMA-IR) ≥ 2.5 was the most significant factor for NASH (OR: 4.100; 95% CI: 1.772-9.487; P = 0.001) and significant factor for liver fibrosis (OR: 2.947; 95% CI: 1.398-6.210; P = 0.004) after the adjustments of the BMI and diabetes. CONCLUSIONS: Metabolic dysregulations are important risk factors in NAFLD progression. The insulin resistance status may play a predominant role in the progression in MAFLD patients.

Chronic hepatitis B infection with concomitant hepatic steatosis: Current evidence and opinion.

With the increasing incidence of obesity and metabolic syndrome worldwide, concomitant nonalcoholic fatty liver disease (NAFLD) in patients with chronic hepatitis B (CHB) has become highly prevalent. The risk of dual etiologies, outcome, and mechanism of CHB with concomitant NAFLD have not been fully characterized. In this review, we assessed the overlapping prevalence of metabolic disorders and CHB, assessed the risk of advanced fibrosis/hepatocellular carcinoma in CHB patients concomitant with NAFLD, and discussed the remaining clinical issues to be addressed in the outcome of such patients. We also explored the possible roles of hepatitis B virus in the development of steatosis and discussed difficultiesof histological evaluation. For CHB patients, it is important to address concomitant NAFLD through lifestyle management and disease screening to achieve better prognoses. The assessment of progressive changes and novel therapies for CHB patients concomitant with NAFLD deserve further research.

Etiology and management of liver injury in patients with COVID-19.

The outbreak of novel coronavirus disease 2019 (COVID-19) has resulted in global emergence. With the expansion of related research, in addition to respiratory symptoms, digestive system involvement such as nausea, vomiting, and diarrhea have also been reported with COVID-19. Besides, abnormal liver function is also frequent in biochemical tests of COVID-19 patients, which is correlated with the severity and mortality of the disease course. The etiology of liver injury in patients with COVID-19 might include viral immunologic injury, drug-induced liver injury, the systemic inflammatory response, hypoxic hepatitis, and the exacerbation of preexisting liver disease. Although liver injuries in COVID-19 are often transient and reversible, health workers need to pay attention to preexisting liver disease, monitor liver function, strengthen supportive treatment, and reduce the chance of drug-induced liver injury. This article reviews the epidemiological characteristics, etiology, management, and preventive strategies for liver injury in patients with COVID-19.

Prevalence, clinical characteristics, risk factors, and indicators for lean Chinese adults with nonalcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic diseases in the world. Nowadays, the percentage of non-obese or lean patients with NAFLD is increasing. NAFLD in non-obese populations, especially the lean subgroup with a normal waist circumference (WC), might lead to more problems than obese individuals, as these individuals may not visit clinics for NAFLD diagnosis or ignore the diagnosis of NAFLD. If the precise characteristics of these populations, especially the lean subgroup, are identified, the clinicians would be able to provide more appropriate advice and treatment to these populations. AIM: To investigate the prevalence, clinical characteristics, risk factors, and possible indicators for NAFLD in lean Chinese adults with a normal WC. METHODS: People without diabetes mellitus or significant alcohol consumption who underwent routine health examinations were included. Their fatty liver index (FLI), abdominal ultrasonography results, and controlled attenuation parameter were all assessed. Genotyping for single-nucleotide polymorphisms associated with NAFLD was performed in another small group consisting of biopsy-proven NAFLD subjects and healthy controls. RESULTS: A total of 2715 subjects who underwent routine health examinations were included in the study. Among 810 lean participants with a normal WC, 142 (17.5%) fulfilled the diagnostic criteria for NAFLD. Waist-height ratio, hemoglobin, platelets, and triglycerides were significant factors associated with the presence of NAFLD in these participants. The appropriate cut-off value of the FLI score in screening for NAFLD in the lean subjects with a normal WC was 25.15, which had a 77.8% sensitivity and 75.9% specificity. There was no significant difference in the single-nucleotide polymorphisms in the SIRT1, APOC3, PNPLA3, AGTR1, and PPARGC1A genes between lean subjects with and without NAFLD (P < 0.05). CONCLUSION: NAFLD is not uncommon in lean Chinese adults even with a normal WC. Metabolic factors, rather than genetic factors, may play important roles in the development of NAFLD in this population. A lower cut-off value of the FLI score in screening for NAFLD should be used for lean Chinese adults with a normal WC.

Effects and therapeutic mechanism of Yinzhihuang on steatohepatitis in rats induced by a high-fat, high-cholesterol diet.

OBJECTIVES: We aimed to investigate the therapeutic mechanism of Yinzhihuang (YZH) liquid, a traditional Chinese medicine mainly composed of extracts of four components, on nonalcoholic steatohepatitis (NASH) induced by a high-fat, high-cholesterol diet (HFHCD) in rats. METHODS: Altogether 30 Sprague-Dawley rats were randomized into three groups: control, the model group (HFHCD + saline) and the treatment group (HFHCD + YZH). Liver histological features and serum biochemical parameters were assessed by the end of the 16th week. RNA sequencing and protein mass spectrometry detection were performed. The genes and proteins expressed differentially were subjected to KEGG pathway enrichment analysis and included in a network-based regulatory model. RESULTS: The weight, liver and fat indices and serum alanine transaminase, aspartate transaminase and total cholesterol levels of the HFHCD + YZH group were all significantly lower than those of the HFHCD + saline group. Moreover, their hepatic steatosis, ballooning and lobular inflammation were relieved, and 64 hepatic genes and 73 hepatic proteins were found to be reversed in their expression patterns after YZH treatment (P < 0.05). The network-based regulatory model showed that these deregulated genes and proteins were mainly involved in oxidative phosphorylation, Toll-like receptor, nucleotide-binding oligomerization domain-like receptor, peroxisome proliferator-activated receptor signaling, nuclear factor-kappa B tumor necrosis factor signaling pathways and fatty acid metabolism. CONCLUSION: YZH could alleviate NASH in HFHCD-fed rats by inhibiting lipogenesis, accelerating lipid ß-oxidation, alleviating oxidative stress and relieving necroinflammation in the liver.

Lipotoxic Hepatocyte-Derived Exosomal MicroRNA 192-5p Activates Macrophages Through Rictor/Akt/Forkhead Box Transcription Factor O1 Signaling in Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIMS: Hepatic macrophages can be activated by many factors such as gut-derived bacterial components and factors released from damaged hepatocytes. Macrophage polarization toward a proinflammatory phenotype (M1) represents an important event in the disease progression of nonalcoholic fatty liver disease (NAFLD). However, the underlying molecular mechanisms remain incompletely understood. Exosomes have been identified as important mediators for cell-cell communication by transferring various biological components such as microRNAs (miRs), proteins, and lipids. The role of exosomes in crosstalk between hepatocytes and macrophages in disease progression of NAFLD is yet to be explored. APPROACH AND RESULTS: In the present study, we reported that lipotoxic injury-induced release of hepatocyte exosomes enriched with miR-192-5p played a critical role in the activation of M1 macrophages and hepatic inflammation. Serum miR-192-5p levels in patients with NAFLD positively correlated with hepatic inflammatory activity score and disease progression. Similarly, the serum miR-192-5p level and the number of M1 macrophages, as well as the expression levels of the hepatic proinflammatory mediators, were correlated with disease progression in high-fat high-cholesterol diet-fed rat models. Lipotoxic hepatocytes released more miR-192-5p-enriched exosomes than controls, which induced M1 macrophage (cluster of differentiation 11b-positive [CD11b+ ]/CD86+ ) activation and increase of inducible nitric oxide synthase, interleukin 6, and tumor necrosis factor alpha expression. Furthermore, hepatocyte-derived exosomal miR-192-5p inhibited the protein expression of the rapamycin-insensitive companion of mammalian target of rapamycin (Rictor), which further inhibited the phosphorylation levels of Akt and forkhead box transcription factor O1 (FoxO1) and resulted in activation of FoxO1 and subsequent induction of the inflammatory response. CONCLUSIONS: Hepatocyte-derived exosomal miR-192-5p plays a critical role in the activation of proinflammatory macrophages and disease progression of NAFLD through modulating Rictor/Akt/FoxO1 signaling. Serum exosomal miR-192-5p represents a potential noninvasive biomarker and therapeutic target for nonalcoholic steatohepatitis.

Therapeutic effect and autophagy regulation of myriocin in nonalcoholic steatohepatitis.

BACKGROUND: Ceramide plays pathogenic roles in nonalcoholic fatty liver disease (NAFLD) via multiple mechanisms, and as such inhibition of ceramide de novo synthesis in the liver may be of therapeutically beneficial in patients with NAFLD. In this study, we aimed to explore whether inhibition of ceramide signaling by myriocin is beneficial in animal model of NAFLD via regulating autophagy. METHODS: Sprague Dawley rats were randomly divided into three groups: standard chow (n = 10), high-fat diet (HFD) (n = 10) or HFD combined with oral administration of myriocin (0.3 mg/kg on alternate days for 8 weeks) (n = 10). Liver histology and autophagy function were measured. HepG2 cells were incubated with fatty acid with or without myriocin treatment. Lipid accumulation and autophagy markers in the HepG2 cells were analyzed. Serum ceramide changes were studied in 104 subjects consisting healthy adults, liver biopsy-proven patients with NAFLD and liver biopsy-proven patients with chronic hepatitis B (CHB). RESULTS: Myriocin reversed the elevated body weight and serum transaminases and alleviated dyslipidemia in HFD fed rats. Myriocin treatment significantly attenuated liver pathology including steatosis, lobular inflammation and ballooning. By qPCR analysis, it was revealed that myriocin corrected the expression pattern of fatty acid metabolism associated genes including Fabp1, Pparα, Cpt-1α and Acox-2. Further, myriocin also restored the impaired hepatic autophagy function in rats with HFD-induced NASH, and this has been verified in HepG2 cells. Among the sphingolipid species that we screened in lipidomic profiles, significantly increased ceramide was observed in NASH patients as compared to the controls and non-NASH patients, regardless of whether or not they have active CHB. CONCLUSIONS: Ceramide may play an important regulatory role in the autophagy function in the pathogenesis of NASH. Hence, blockade of ceramide signaling by myriocin may be of therapeutically beneficial in NASH. TRIAL REGISTRATION: Registration ID: ChiCTR-DDT-13003983 . Data of registration: 13 May, 2013, retrospectively registered.

Trimethylamine N-oxide attenuates high-fat high-cholesterol diet-induced steatohepatitis by reducing hepatic cholesterol overload in rats.

BACKGROUND: Trimethylamine N-oxide (TMAO) has been shown to be involved in cardiovascular disease (CVD). However, its role in nonalcoholic steatohepatitis (NASH) is unknown. AIM: To determine the effect of TMAO on the progression of NASH. METHODS: A rat model was induced by 16-wk high-fat high-cholesterol (HFHC) diet feeding and TMAO was administrated by daily oral gavage for 8 wk. RESULTS: Oral TMAO intervention attenuated HFHC diet-induced steatohepatitis in rats. Histological evaluation showed that TMAO treatment significantly alleviated lobular inflammation and hepatocyte ballooning in the livers of rats fed a HFHC diet. Serum levels of alanine aminotransferase and aspartate aminotransferase were also decreased by TMAO treatment. Moreover, hepatic endoplasmic reticulum (ER) stress and cell death were mitigated in HFHC diet-fed TMAO-treated rats. Hepatic and serum levels of cholesterol were both decreased by TMAO treatment in rats fed a HFHC diet. Furthermore, the expression levels of intestinal cholesterol transporters were detected. Interestingly, cholesterol influx-related Niemann-Pick C1-like 1 was downregulated and cholesterol efflux-related ABCG5/8 were upregulated by TMAO treatment in the small intestine. Gut microbiota analysis showed that TMAO could alter the gut microbial profile and restore the diversity of gut flora. CONCLUSION: These data suggest that TMAO may modulate the gut microbiota, inhibit intestinal cholesterol absorption, and ameliorate hepatic ER stress and cell death under cholesterol overload, thereby attenuating HFHC diet-induced steatohepatitis in rats. Further studies are needed to evaluate the influence on CVD and define the safe does of TMAO treatment.