Progression Of Fibrosis In Nonalcoholic Fatty Liver Disease Research Articles

1313-P: The Prevalences of NAFLD and Liver Fibrosis Are High in Individuals with Type 1 Diabetes and Increase with Disease Progression

Introduction: Approximately 30% of the global population has nonalcoholic fatty liver disease (NAFLD). This can result in nonalcoholic steatohepatitis (NASH) and liver fibrosis (2% in general population). NAFLD with fibrosis increases overall morbidity and mortality significantly. T2D increases the risk of fibrosis progression in NAFLD, but little is known about NAFLD in T1D. Therefore, the aim of this study was to assess the prevalence of NAFLD and liver fibrosis in T1D. Methods: In this cross-sectional study 453 individuals with T1D were included for analyses (41.0 ±14years old, 64% female, HbA1c 55.6 ±12mmol/mol, median T1D duration 14 [IQR: 6-29] years. Participants underwent a FibroScan® to assess liver stiffness, with a cut-off of 238 dB/m for steatosis and 7.0 kPa for fibrosis. Data analyses was performed in R studio, using a Students T- or Mann-Whitney U test, as appropriate. Results: Prevalence of liver steatosis was 29.5% and fibrosis was 7.7%. Steatosis was significantly higher in individuals with longer T1D duration (median:15 [IQR:7-25] vs. 23 [9-33] years), higher 24-hour insulin dose (34 [24-47] vs. 46 [33-62] units), higher BMI (mean 24.3±SD 3.5 vs. 27.9±4.6 kg/m2), higher CRP levels (1.0 [0.5-2.1] vs. 1.6 [0.8, 3.7] mg/L), higher triglyceride levels (0.6±0.3 vs. 0.8±0.5 mmol/L) and lower TIR (67 [51-82] vs. 62 [48-75] %). Presence of fibrosis was associated with a longer duration of T1D (16 [7-27] vs. 30 [20-39] years) a higher 24-hour insulin (36.0 [26-50] vs. 42 [34-63] units), higher BMI (25.1±4.1 vs. 27.8±4.6 kg/m2), higher CRP levels (1.2 [0.6-2.4] vs 1.5 [0.8-3.9] mg/L) and lower TIR (67 [51, 8] vs. 58 [46, 71] %). Conclusion: The prevalence of NAFLD and liver fibrosis was 7.7% in individuals with T1D. Duration of T1D, markers of insulin resistance, glycemic control and inflammation are likely contributors to this high prevalence and more attention should be paid to this possible complication. Disclosure C. Fuhri Snethage: None. A.S. Meijnikman: None. P. de Groen: None. C. Callender: None. E. Rampanelli: None. C.B. Brouwer: None. D. van Raalte: Consultant; Boehringer Ingelheim and Eli Lilly Alliance, AstraZeneca, Merck & Co., Inc. Research Support; Boehringer Ingelheim and Eli Lilly Alliance, AstraZeneca, Merck & Co., Inc. M. Nieuwdorp: Advisory Panel; caelus health. N. Hanssen: Research Support; Novo Nordisk. Consultant; Novo Nordisk. Funding DNF DON Grant 2020 (2020.10.002)

Evaluation of ABCA1 gene polymorphism as a prognostic index of fibrosis progression in NAFLD patients.

It had been evident that non-alcoholic fatty liver disease (NAFLD) is the new era epidemic. Despite emergence of many drugs on the pipeline that considered candidates to cure NAFLD/NASH, the critical need for defining the cohort liable to fibrosis progression is yet unmet. Evaluate ABCA1 (rs1800977) genotyping as a noninvasive predictor of liver fibrosis severity. This study included 118 liver biopsy-proven NAFLD-patients. According to Metavir-fibrosis-staging, cases were divided to early fibrosis (74 cases), and 44 cases with significant fibrosis (>F2), added to 49 healthy control subjects. All patients were subjected to liver function tests, lipids profile, triglyceride TG index, and hepatic steatosis index (HSI) and real-time PCR ABCA1 SNP (rs1800977). Significant differences in transaminases (p > .05), albumin (p < .009), cholesterol (p0.03), low density lipoproteins (LDL) (0.006), triglycerides (p < .001), HSI (p < .001), FIB4 (p < .001) and APRI (p < .001) were reported in those with significant than early fibrosis and control groups. CC was the most prevalent in significant (36.4%) than early fibrosis (13.5%) and control groups (8.2%), with prevalence of C allele in significant fibrosis (p ≤ .003). Univariate analysis revealed that DM (p ≤ .001), TG index (p ≤ .022), cholesterol (p ≤ .03), HSI (p ≤ .006), LDL (p ≤ .02), HDL (p ≤ .01), APRI (p ≤ .02) and CC genotype (p ≤ .005) were the main factors affecting fibrosis progression in NAFLD. However multivariate analysis proved only the role of HSI (p ≤ .005), LDL (p ≤ .02), HDL (p ≤ .003) and CC genotype (p ≤ .03) in predicting fibrosis severity. Dyslipidemias, hepatic steatosis index and ABCA1 (rs1800977) gene polymorphism CC genotype; were the only independent predictors of advanced fibrosis in NAFLD-patients.

The Protection Conferred by HSD17B13 rs72613567 on Hepatic Fibrosis Is Likely Mediated by Lowering Ballooning and Portal Inflammation

The Protection Conferred by HSD17B13 rs72613567 on Hepatic Fibrosis Is Likely Mediated by Lowering Ballooning and Portal Inflammation

Decreased Serum zinc, selenium, and vitamin E as possible risk factors of hepatic fibrosis in non-alcoholic fatty liver disease.

The incidence of non-alcoholic fatty liver disease (NAFLD) has been significantly growing in recent years. Although the pathophysiology of fibrosis progression in NAFLD is not yet known, oxidative stress and inflammation have been known to have a major role in the development of NASH. Understanding the impact of micronutrients in NAFLD could potentially help us better understand NAFLD pathogenesis. Assessing the serum levels of Zn, Se, and Vitamin E and their relation to the development of hepatic fibrosis in NAFLD patients. This study included 80 NAFLD patients and 40 healthy controls. All of the patients were subjected to abdominal ultrasound and FibroScan examination (to estimate hepatic fibrosis and steatosis degree), and the serum levels of Zn, Se, and vitamin E were evaluated. A statistically significant difference in the serum levels of Zn and Se was observed between the NAFLD group and the control group (P-value = 0.04 and 0.05, respectively). The serum levels of Zn and Se were independently related to the presence of hepatic fibrosis in NAFLD. However, serum vitamin E was not related to the severity of NAFLD. Furthermore, no significant difference in the levels of Zn, Se, and vitamin E was observed between the different groups of NAFLD patients categorized according to the degree of steatosis and the control group. Reduced serum levels of Zn and Se can be considered a possible risk factor for hepatic fibrosis in NAFLD. Deficiency in these micronutrients could play a role in the pathogenesis of NAFLD.

The macrophage-associated microRNA-4715-3p / Gasdermin D axis potentially indicates fibrosis progression in nonalcoholic fatty liver disease: evidence from transcriptome and biological data

ABSTRACT Nonalcoholic fatty liver disease (NAFLD) is highly possible to progress to cirrhosis, malignancy, and liver failure through fibrogenesis. The enormous potential of pathogenetic and therapeutic targets in NAFLD has been revealed. This study aimed to explore novel factors potentially indicating or mediating NAFLD progression. Multiple bulk and single-cell RNA sequencing datasets were used, in which landscapes of cell populations were clarified to characterize immune cell infiltration. Significantly high infiltration of macrophages (MPs) was discovered during NAFLD progression. Samples in bulk NASH datasets were regrouped by MP level. Highly differentially expressed genes (DEGs) were identified in the Ctrl vs. NASH comparison, low MP vs. high MP comparison, and the weighted gene co-expression network analysis (WGCNA) clusters. Eight hub genes were identified as promising targets by protein–protein interaction analysis and validated in fibrosis progression, microRNA (miR)–protein interactions were predicted, and the hub genes were verified in a free fatty acid (FFA)-induced macrophage injury model. The results showed that Gasdermin D (GSDMD) was upregulated with fibrosis progression in NAFLD and was associated with macrophage infiltration. In addition, a potential regulator (miR-4715-3p) was correlated with GSDMD. The miR-4715-3p/GSDMD axis potentially modulates macrophage-associated immunity and indicates fibrosis progression in NAFLD.

Glycemic control predicts the risk of hepatic fibrosis in biopsy-proven NAFLD: a possible mediating role for leukemia inhibitory factor?

Background Despite the clear link between nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus, little is understood about how glycemic control impacts histological severity. We aimed to investigate the deeper association between hemoglobin A1c (HbA1c) and the histologic severity of liver fibrosis. Methods A total of 568 adults with biopsy-proven NAFLD from the PERSONS cohort in Wenzhou were enrolled. The association between mean HbA1c and hepatic histological features was investigated with ordinal logistic regression. Generalized additive models were used to identify the non-linear relationship between HbA1c and increased fibrosis stage (stage F ​≥ ​3). Causal mediation analysis was performed to calculate the indirect effect of the relationship between HbA1c and hepatic fibrosis mediated by cytokines. Results Every 1% increase in mean HbA1c was associated with 16% higher odds of increased fibrosis stage (odds ratio 1.16, 95%CI 1.04–1.30), even after adjustment for confounding factors. There was a non-linear association between HbA1c and increased fibrosis stage (stage F ​≥ ​3), and the HbA1c inflection point was 9.2%. In particular, the ORs on the left and right sides of this inflection point were 2.1 (95%CI 1.4–3.3) and 0.1 (95%CI 0–4.8), respectively. 7% of the association (OR 1.07, 95%CI 1.01–1.12) between HbA1c and liver fibrosis was mediated by leukemia inhibitory factor. Conclusions Glycemic control predicts severity of hepatic fibrosis and leukemia inhibitory factor plays an intermediary role between them, and thus optimizing glycemic control may be a means of modifying the risk of fibrosis progression in NAFLD.

Differential iNKT and T Cells Activation in Non-Alcoholic Fatty Liver Disease and Drug-Induced Liver Injury.

Background: Non-alcoholic fatty liver disease (NAFLD) and idiosyncratic drug-induced liver injury (DILI) could share molecular mechanisms involving the immune system. We aimed to identify activation immunological biomarkers in invariant natural killer T (iNKT) and CD4/CD8+ T cells in NAFLD and DILI. Methods: We analyzed the activation profile (CD69, CD25, and HLA-DR) and natural killer group 2 member D (NKG2D) on iNKT cells, and CD4/CD8 T cells in peripheral blood mononuclear cells from NAFLD, with or without significant liver fibrosis, and DILI patients. Results: There was an increase in iNKT cells in NAFLD patients compared to DILI or control subjects. Regarding the cellular activation profile, NAFLD with significant liver fibrosis (F ≥ 2) displayed higher levels of CD69+iNKT cells compared to NAFLD with none or mild liver fibrosis (F ≤ 1) and control patients. CD69+iNKT positively correlated with insulin resistance, aspartate aminotransferase (AST) level, liver fibrosis-4 index (FIB4) and AST to Platelet Ratio Index (APRI). DILI patients showed an increase in CD69+ and HLA-DR+ in both CD4+ and CD8+ T cells, detecting the most relevant difference in the case of CD69+CD8+ T cells. Conclusions: CD69+iNKT may be a biomarker to assess liver fibrosis progression in NAFLD. CD69+CD8+ T cells were identified as a potential distinctive biomarker for distinguishing DILI from NAFLD.

Relationships of Dietary Habits and Physical Activity Status with Non-Alcoholic Fatty Liver Disease Featuring Advanced Fibrosis.

(1) Aim: Hepatic fibrosis is a prognostic factor for disease progression in non-alcoholic fatty liver disease (NAFLD). We aimed to determine the relationships between diet, physical activity, and the progression of liver fibrosis. (2) Methods: The 349 participants were categorized by their FibroScan-aspartate aminotransferase score, and they completed a questionnaire regarding their diet and physical activity. (3) Results: There were 233 patients in the negative-on-screening group, 78 in the gray zone group, and 38 in the positive-on-screening group. The frequencies of consumption of soybeans and soybean products and of light-colored vegetables were lower in the positive group; whereas the frequencies of consumption of snack food and fried sweets, jelly and pudding, fried food, and butter, lard, and beef tallow were higher. The odds ratios for the fibrosis progression in patients who consumed fried food ≥4 times/week was 2.21. The positive group also showed lower physical activity level (PAL) and exercise (Ex, metabolic equivalents for tasks (METs)/hour/week). The patients who undertook Ex at >7.5 had an odds ratio of 0.21 for the fibrosis progression. (4) Conclusion: High consumption of fried food and low Ex are risk factors for the fibrosis progression in NAFLD.

Eugenol modulates insulin sensitivity by upregulating insulin receptor substrate-2 in non-alcoholic fatty liver disease in rats.

The purpose of this study was to estimate the possible modulatory effect of Eugenol (EUG) on insulin resistance (IR) and liver fibrosis in high-fat diet (HFD)-induced experimental non-alcoholic fatty liver disease (NAFLD) in rats. It has been shown that EUG, a natural phenolic compound, has anti-hyperglycaemic, antioxidant and anti-inflammatory actions. For 8 consecutive weeks, standard rat chow diet (control group, EUG only treated group) or HFD (HFD group and HFD+EUG-treated group) were fed to rats daily. HFD+EUG-treated group and EUG only treated group were administered EUG (10 mg/kg) orally three times per week. Various indices of hepatotoxicity, oxidative stress, indicators of inflammation and liver fibrosis were investigated. HFD-induced liver transaminases and triglycerides (TGs) were significantly decreased and histopathological lesions were improved with EUG treatment. EUG significantly improved IR evoked by HFD, as demonstrated by Homeostasis model assessment for insulin resistance (HOMA-IR) and increased insulin receptor substrate-2 (IRS-2) sensitivity. In addition, EUG improved oxidative stress damage elicited by HFD as shown by the restoration of reduced glutathione (GSH) level and nuclear factor erythroid-2-related factor 2 (Nrf-2) expression and plummeting lipid peroxidation. Further, EUG lessened pro-inflammatory cytokines surge [tumour necrosis factor-α (TNF-α) and IL-6] via inhibiting nuclear factor-κB (NF-κB) stimulation. As markers of fibrosis, EUG reduced collagen accumulation and smooth muscle alpha actin (SMaA) and TGF-β expression. EUG may have protective effect against progression of fibrosis in NAFLD. The antifibrotic effect of EUG is probably due to EUG's antioxidant, anti-inflammatory and anti-hyperglycaemic.

Bioengineered Multicellular Liver Microtissues for Modeling Advanced Hepatic Fibrosis Driven Through Non-Alcoholic Fatty Liver Disease.

Despite considerable efforts in modeling liver disease in vitro, it remains difficult to recapitulate the pathogenesis of the advanced phases of non-alcoholic fatty liver disease (NAFLD) with inflammation and fibrosis. Here, a liver-on-a-chip platform with bioengineered multicellular liver microtissues is developed, composed of four major types of liver cells (hepatocytes, endothelial cells, Kupffer cells, and stellate cells) to implement a human hepatic fibrosis model driven by NAFLD: i) lipid accumulation in hepatocytes (steatosis), ii) neovascularization by endothelial cells, iii) inflammation by activated Kupffer cells (steatohepatitis), and iv) extracellular matrix deposition by activated stellate cells (fibrosis). In this model, the presence of stellate cells in the liver-on-a-chip model with fat supplementation showed elevated inflammatory responses and fibrosis marker up-regulation. Compared to transforming growth factor-beta-induced hepatic fibrosis models, this model includes the native pathological and chronological steps of NAFLD which shows i) higher fibrotic phenotypes, ii) increased expression of fibrosis markers, and iii) efficient drug transport and metabolism. Taken together, the proposed platform will enable a better understanding of the mechanisms underlying fibrosis progression in NAFLD as well as the identification of new drugs for the different stages of NAFLD.

Expression levels of gastrointestinal hormones in the progression of liver fibrosis in patients with nonalcoholic fatty liver disease

Objective To investigate the changes in gastrointestinal hormones during the progression of liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD), and to provide a basis for digestive function impairment. Methods A prospective analysis was performed for 326 patients with NAFLD who attended the outpatient service and were hospitalized and treated in Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine from October 2018 to June 2020, and FibroTouch was used to measure liver stiffness measurement (LSM). According to the presence or absence of liver fibrosis, they were divided into non-liver fibrosis group (group A, 161 patients with LSM Results Comparison of liver function and gastrointestinal hormones showed that there were significant differences between groups A and B in alanine aminotransferase (ALT) (Z=-3.778, P Conclusion Liver fibrosis progression in NAFLD can affect gallbladder contraction function and gastrointestinal function, and measurement of the serum levels of CCK and LPS has an important clinical value in the early diagnosis and treatment of digestive diseases related to gallbladder contraction function and gastrointe stinal function in NAFLD patients with liver fibrosis.

Mitochondrial dysfunction as a mechanistic biomarker in patients with non-alcoholic fatty liver disease (NAFLD)

BackgroundDysfunctional metabolism lies at the centre of the pathogenesis for Non-Alcoholic Fatty Liver Disease (NAFLD) and involves mitochondrial dysfunction, lipid dysmetabolism and oxidative stress. This study, for the first time, explores real-time energy changes in peripheral blood and corresponding metabolite changes, to investigate whether mitochondria-related immunometabolic biomarkers can predict progression in NAFLD. MethodsThirty subjects divided into 3 groups were assessed: NAFLD with biopsy-proven mild fibrosis (n = 10), severe fibrosis (n = 10) and healthy controls (HC, n = 10). Mitochondrial functional analysis was performed in a Seahorse XFp analyzer in live peripheral blood mononuclear cells (PBMCs). Global metabolomics quantified a broad range of human plasma metabolites. Mitochondrial carbamoyl phosphate synthase 1(CPS-1), Ornithine transcarbamoylase (OTC), Fibroblast growth factor-21 (FGF-21) and a range of cytokines in plasma were measured by ELISA. ResultsNAFLD patients with severe fibrosis demonstrated reduced maximal respiration (106 ± 25 versus 242 ± 62, p < 0.05) and reserve capacity (56 ± 16 versus 184 ± 42, p = 0.006) compared to mild/moderate fibrosis. Comparing mild/moderate vs severe liver fibrosis in patients with NAFLD, 14 out of 493 quantified metabolites were significantly changed (p < 0.05). Most of the amino acids modulated were the urea cycle (UC) components which included citrulline/ornithine ratio, arginine and glutamate. Plasma levels of CPS-1 and FGF-21 were significantly higher mild versus severe fibrosis in NAFLD patients. This novel panel generated an area under the ROC of 0.95, sensitivity of 100% and specificity 80% and p = 0.0007 (F1-F2 versus F3-F4). ConclusionProgression in NAFLD is associated with mitochondrial dysfunction and changes in metabolites associated with the urea cycle. We demonstrate a unique panel of mitochondrial-based, signatures which differentiate between stages of NAFLD. Lay summaryMitochondrial dysfunction in peripheral cells along with alterations in metabolites of urea cycle act as a sensor of hepatocyte mitochondrial damage. These changes can be measured in blood and together represent a unique panel of biomarkers for progression of fibrosis in NAFLD.

Magnetic Resonance-Based Assessments Better Capture Pathophysiologic Profiles and Progression in Nonalcoholic Fatty Liver Disease.

BackgroundSeveral noninvasive tools are available for the assessment of nonalcoholic fatty liver disease (NAFLD) including clinical and blood biomarkers, transient elastography (TE), and magnetic resonance imaging (MRI) techniques, such as proton density fat fraction (MRI-PDFF) and magnetic resonance elastography (MRE). In the present study, we aimed to evaluate whether magnetic resonance (MR)-based examinations better discriminate the pathophysiologic features and fibrosis progression in NAFLD than other noninvasive methods.MethodsA total of 133 subjects (31 healthy volunteers and 102 patients with NAFLD) were subjected to clinical and noninvasive NAFLD evaluation, with additional liver biopsy in some patients (n=54).ResultsMRI-PDFF correlated far better with hepatic fat measured by MR spectroscopy (r=0.978, P<0.001) than with the TE controlled attenuation parameter (CAP) (r=0.727, P<0.001). In addition, MRI-PDFF showed stronger correlations with various pathophysiologic parameters for cellular injury, glucose and lipid metabolism, and inflammation, than the TE-CAP. The MRI-PDFF and TE-CAP cutoff levels associated with abnormal elevation of serum alanine aminotransferase were 9.9% and 270 dB/m, respectively. The MRE liver stiffness measurement (LSM) showed stronger correlations with liver enzymes, platelets, complement component 3, several clinical fibrosis scores, and the enhanced liver fibrosis (ELF) score than the TE-LSM. In an analysis of only biopsied patients, MRE performed better in discriminating advanced fibrosis with a cutoff value of 3.9 kPa than the TE (cutoff 8.1 kPa) and ELF test (cutoff 9.2 kPa).ConclusionOur results suggest that MRI-based assessment of NAFLD is the best non-invasive tool that captures the histologic, pathophysiologic and metabolic features of the disease.

Epidemiology: Pathogenesis, and Diagnostic Strategy of Diabetic Liver Disease in Japan.

Type 2 diabetes (T2D) is closely associated with nonalcoholic fatty liver disease (NAFLD). Nonalcoholic steatohepatitis (NASH), a severe form of NAFLD, can lead to cirrhosis, hepatocellular carcinoma (HCC), and hepatic decompensation. Patients with T2D have twice the risk of HCC incidence compared with those without T2D. Because the hepatic fibrosis grade is the main determinant of mortality in patients with NAFLD, identifying patients with advanced fibrosis using non-invasive tests (NITs) or imaging modalities is crucial. Globally, the fibrosis-4 index (FIB-4 index), NAFLD fibrosis score, and enhanced liver fibrosis test have been established to evaluate hepatic fibrosis. Two-step algorithms using FIB-4 index as first triaging tool are globally accepted. It remains unknown which kinds of NITs or elastography are best as the second step tool. In Japan, type IV collagen 7s or the CA-fibrosis index (comprising type IV collagen 7s and aspartate aminotransferase (AST)) is believed to precisely predict advanced fibrosis in NAFLD. Patients with NAFLD who have high non-invasive test results should be screened for HCC or esophageal varices. Risk factors of rapid fibrosis progression in NAFLD includes age, severe obesity, presence of T2D, menopause in women, and a patatin-like phospholipase domain containing the 3 GG genotype. Patients with NAFLD who have these risk factors should be intensively treated with lifestyle modification or pharmacotherapies for preventing liver-related mortality.

Clinical Utility of an Increase in Magnetic Resonance Elastography in Predicting Fibrosis Progression in Nonalcoholic Fatty Liver Disease.

Cross-sectional studies have shown that magnetic resonance elastography (MRE) is accurate in the noninvasive detection of advanced fibrosis in nonalcoholic fatty liver disease (NAFLD). However, there are limited data on the longitudinal association between an increase in liver stiffness on MRE and fibrosis progression in NAFLD. Therefore, using a well-characterized prospective cohort of patients with biopsy-proven NAFLD, we aimed to examine the longitudinal association between a 15% increase in liver stiffness on MRE and fibrosis progression in NAFLD. This prospective cohort study included 102 patients (62.7% women) with biopsy-proven NAFLD who underwent contemporaneous MRE and liver biopsy at baseline followed by a repeat paired liver biopsy and MRE assessment. The primary outcome was odds of fibrosis progression by one or more stage as assessed by the Nonalcoholic Steatohepatitis Clinical Research Network histologic scoring system. The mean (±SD) of age and body mass index (BMI) were 52 (±14) years and 32.6 (±5.3) kg/m2 , respectively. The median time interval between the two paired assessments was 1.4years (interquartile range 2.15years). The number of patients with fibrosis stages 0, 1, 2, 3, and 4 was 27, 36, 12, 17, and 10, respectively. In unadjusted analysis, a 15% increase in MRE was associated with increased odds of histologic fibrosis progression (odds ratio [OR], 3.56; 95% confidence interval [CI], 1.17-10.76; P=0.0248). These findings remained clinically and statistically significant even after multivariable adjustment for age, sex, and BMI (adjusted OR, 3.36; 95% CI, 1.10-10.31; P=0.0339). A 15% increase in MRE was the strongest predictor of progression to advanced fibrosis (OR, 4.90; 95% CI, 1.35-17.84; P=0.0159). A 15% increase in liver stiffness on MRE may be associated with histologic fibrosis progression and progression from early fibrosis to advanced fibrosis.

Ammonia Scavenging Prevents Progression of Fibrosis in Experimental Nonalcoholic Fatty Liver Disease.

In nonalcoholic fatty liver disease (NAFLD), fibrosis is the most important factor contributing to NAFLD-associated morbidity and mortality. Prevention of progression and reduction in fibrosis are the main aims of treatment. Even in early stages of NAFLD, hepatic and systemic hyperammonemia is evident. This is due to reduced urea synthesis; and as ammonia is known to activate hepatic stellate cells, we hypothesized that ammonia may be involved in the progression of fibrosis in NAFLD. In a high-fat, high-cholesterol diet-induced rodent model of NAFLD, we observed a progressive stepwise reduction in the expression and activity of urea cycle enzymes resulting in hyperammonemia, evidence of hepatic stellate cell activation, and progressive fibrosis. In primary, cultured hepatocytes and precision-cut liver slices we demonstrated increased gene expression of profibrogenic markers after lipid and/or ammonia exposure. Lowering of ammonia with the ammonia scavenger ornithine phenylacetate prevented hepatocyte cell death and significantly reduced the development of fibrosis both in vitro in the liver slices and in vivo in a rodent model. The prevention of fibrosis in the rodent model was associated with restoration of urea cycle enzyme activity and function, reduced hepatic ammonia, and markers of inflammation. The results of this study suggest that hepatic steatosis results in hyperammonemia, which is associated with progression of hepatic fibrosis. Reduction of ammonia levels prevented progression of fibrosis, providing a potential treatment for NAFLD.

Metabolically healthy versus unhealthy obesity and risk of fibrosis progression in non-alcoholic fatty liver disease.

Little is known about the impact of metabolically healthy obesity on fibrosis progression in non-alcoholic fatty liver disease (NAFLD). We investigated the association of body mass index (BMI) category, body fat percentage and waist circumference with worsening of noninvasive fibrosis markers in metabolically healthy and unhealthy individuals with NAFLD. A cohort study was performed on 59957 Korean adults with NAFLD (13285 metabolically healthy and 46672 metabolically unhealthy individuals) who were followed for a median of 7.7years. Being metabolically healthy was defined as not having any metabolic syndrome component and having a homoeostasis model assessment of insulin resistance <2.5. Progression from low to intermediate or high probability of advanced fibrosis was assessed using the NAFLD fibrosis score (NFS). During 339253.1 person-years of follow-up, 9857 subjects with low NFS at baseline progressed to intermediate or high NFS. Among metabolically healthy individuals, the multivariable-adjusted HRs (95% CI) for NFS worsening comparing BMIs 23-24.9, 25-29.9 and ≥30 with a BMI of 18.5-22.9kg/m2 were 1.19 (1.00-1.42), 1.79 (1.52-2.10) and 3.52 (2.64-4.69), respectively, whereas the corresponding HRs (95% CI) in metabolically unhealthy individuals were 1.37 (1.24-1.52), 2.18 (1.99-2.39) and 4.26 (3.83-4.75). A similar trend was observed in the analyses using body fat and waist circumference. In the large-scale cohort of young and middle-aged individuals with NAFLD, BMI was positively associated with worsening of noninvasive fibrosis marker regardless of metabolic health status. Excess adiposity per se, even without accompanying metabolic health status, may contribute to fibrosis progression in NAFLD.

Review article: emerging role of the gut microbiome in the progression of nonalcoholic fatty liver disease and potential therapeutic implications.

SummaryBackgroundNonalcoholic fatty liver disease (NAFLD) is a prevalent disorder associated with obesity and diabetes. Few treatment options are effective for patients with NAFLD, but connections between the gut microbiome and NAFLD and NAFLD‐associated conditions suggest that modulation of the gut microbiota could be a novel therapeutic option.AimTo examine the effect of the gut microbiota on pathophysiologic causes of NAFLD and assess the potential of microbiota‐targeting therapies for NAFLD.MethodsA PubMed search of the literature was performed; relevant articles were included.ResultsThe composition of bacteria in the gastrointestinal tract can enhance fat deposition, modulate energy metabolism and alter inflammatory processes. Emerging evidence suggests a role for the gut microbiome in obesity and metabolic syndrome. NAFLD is often considered the hepatic manifestation of metabolic syndrome, and there has been tremendous progress in understanding the association of gut microbiome composition with NAFLD disease severity. We discuss the role of the gut microbiome in NAFLD pathophysiology and whether the microbiome composition can differentiate the two categories of NAFLD: nonalcoholic fatty liver (NAFL, the non‐progressive form) vs nonalcoholic steatohepatitis (NASH, the progressive form). The association between gut microbiome and fibrosis progression in NAFLD is also discussed. Finally, we review whether modulation of the gut microbiome plays a role in improving treatment outcomes for patients with NAFLD.ConclusionsMultiple pathophysiologic pathways connect the gut microbiome with the pathophysiology of NAFLD. Therefore, therapeutics that effectively target the gut microbiome may be beneficial for the treatment of patients with NAFLD.

Increased risk of mortality by fibrosis stage in nonalcoholic fatty liver disease: Systematic review and meta-analysis.

The risk of liver-related mortality increases exponentially with increase in fibrosis stage; these data have important implications in assessing the utility of each stage and benefits of regression of fibrosis from one stage to another. (Hepatology 2017;65:1557-1565).

Renin-Angiotensin System Inhibitors, Type 2 Diabetes and Fibrosis Progression: An Observational Study in Patients with Nonalcoholic Fatty Liver Disease.

BackgroundThe clinical determinants of fibrosis progression in nonalcoholic fatty liver disease (NAFLD) are still under definition.AimTo assess the clinical determinants of fibrosis progression rate (FPR) in NAFLD patients with baseline and follow-up histological evaluation, with a special focus on the impact of pharmacological therapy.MethodsIn an observational cohort of 118 Italian patients from tertiary referral centers, liver histology was evaluated according to Kleiner. Independent predictors of FPR were selected by a stepwise regression approach.ResultsMedian follow-up was 36 months (IQR 24–77). Twenty-five patients (18%) showed some amelioration, 63 (53%) had stability, 30 (25%) had progression of fibrosis. Patients with nonalcoholic steatohepatitis (NASH) had similar demographic and anthropometric features, but a higher prevalence of type 2 diabetes (T2D; p = 0.010), and use of renin-angiotensin axis system (RAS) inhibitors (p = 0.005). Fibrosis progression was dependent of the length of follow-up, and was associated with, but did not require, the presence of NASH (p<0.05). Both fibrosis progression and faster FPR were independently associated with higher APRI score at follow-up, absence of treatment with RAS inhibitors, and T2D diagnosis at baseline (p<0.05). There was a significant interaction between use of RAS inhibitors and T2D on FPR (p = 0.002). RAS inhibitors were associated with slower FPR in patients with (p = 0.011), but not in those without (p = NS) T2D.ConclusionsNASH is not required for fibrosis progression in NAFLD, whereas T2D seems to drive fibrogenesis independently of hepatic inflammation. Use of RAS inhibitors may contrast fibrosis progression especially in high-risk patients affected by T2D.