Systematic review of risk factors for fibrosis progression in non-alcoholic steatohepatitis

Study of the Serum Metabolomic Profile in Nonalcoholic Fatty Liver Disease: Research and Clinical Perspectives

In recent years, metabolomics has attracted great scientific attention. The metabolomics methodology might permit a view into transitional phases between healthy liver and nonalcoholic steatohepatitis. Metabolomics can help to analyze the metabolic alterations that play a main role in the progression of nonalcoholic steatohepatitis. Lipid, glucose, amino acid, and bile acid metabolism should be widely studied to understand the complex pathogenesis of nonalcoholic steatohepatitis. The discovery of new biomarkers would be important for diagnosis and staging of liver disease as well as for the assessment of efficacy of new drugs. Here, we review the metabolomics data regarding nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. We analyzed the main studies regarding the application of metabolomics methodology in the complex context of nonalcoholic steatohepatitis, trying to create a bridge from the basic to the clinical aspects.

Glycine protects against high sucrose and high fat-induced non-alcoholic steatohepatitis in rats

We set out to explore the hypothesis that glycine attenuates non-alcoholic steatohepatitis (NASH) in rats and the possible mechanism by which is it does. Male Sprague-Dawley (SD) rats were fed a diet containing high fat and high sucrose (HSHF) for 24 weeks to induce NASH. Blood and liver tissues were sampled at selected time points throughout the study. Compared with control animals, the content of alanine transaminase (ALT), triglycerides (TGs), and free fatty acids (FFAs) in plasma and the TG and FFA content in the liver was increased from week 4 to 24. The level of TNFα and MCP-1 in plasma, the content of TNFα in the liver, the insulin resistance index, inflammatory cell infiltration, hepatocyte apoptosis, reactive oxygen species (ROS) generation, and endoplasmic stress-associated protein expression were unaltered at 4 weeks. However, these levels were significantly elevated in HSHF fed rats at 12 weeks. At the same time, the level of endotoxin progressively increased from 0.08 ± 0.02 endotoxin EU/ml at week 4 to 0.7 ± 0.19 EU/ml at week 24. Moreover, these rats had elevated blood endotoxin levels, which were positively associated with their NASH indexes. Liver histology progressively worsened over the course of the study. However, we found that with concomitant treatment with glycine, the level of endotoxin decreased, while NASH indexes significantly decreased and liver status markedly improved,. These data support the hypothesis that glycine protects against NASH in rats by decreasing the levels of intestinal endotoxin, alleviating endoplasmic reticulum and oxidative stress.

The bidirectional impacts of alcohol consumption and the metabolic syndrome: Cofactors for progressive fatty liver disease

Current medical practice artificially dichotomises a diagnosis of fatty liver disease into one of two common forms: alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Together, these account for the majority of chronic liver diseases worldwide. In recent years, there has been a dramatic increase in the prevalence of obesity and metabolic syndrome within the general population. These factors now coexist with alcohol consumption in a substantial proportion of the population. Each exposure sensitises the liver to the injurious effects of the other; an interaction that drives and potentially accelerates the genesis of liver disease. We review the epidemiological evidence and scientific literature that considers how alcohol consumption interacts with components of the metabolic syndrome to exert synergistic or supra-additive effects on the development and progression of liver disease, before discussing how these interactions may be addressed in clinical practice.

The Natural History of Nonalcoholic Fatty Liver Disease-An Evolving View

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease worldwide, and its clinical and economic burden will continue to grow with parallel increases in rates of obesity, diabetes, and the metabolic syndrome. Evolving understanding of the natural history of NAFLD suggests that these patients are at risk for disease progression to steatohepatitis, fibrosis, and cirrhosis. Recent studies also suggest that these patients are at elevated risk for cardiovascular-, malignancy-, and liver-related morbidity and mortality, although their risk for progression, decompensation, and hepatocellular carcinoma may be less than that of patients with alternative causes of chronic liver disease.

A critical review of endpoints for non-cirrhotic NASH therapeutic trials

Non-alcoholic steatohepatitis is a disease without a single, specific, diagnostic marker, hence multiple indicators are required to measure therapeutic efficacy. Moreover, drug candidates for non-alcoholic steatohepatitis target many distinct mechanisms that are believed to promote hepatic injury. Therefore, a wide range of endpoints must be reached, sequentially, as required by the drug development process. Some of these endpoints validate the mechanism of action, others are used to anticipate histological efficacy. Histological endpoints are still considered the best predictors of clinical outcome, but they can only be reliably tested in larger, late phase trials. Herein, we will review the rationale and clinical data supporting the use of specific endpoints at different stages of therapeutic trials. We will also discuss the validity and limitations of current phase IIb histological endpoints, particularly a one stage reduction in fibrosis, for their ability to predict progression to cirrhosis, which is the ultimate outcome measure in therapeutic trials.

Activated carbon N-acetylcysteine microcapsule protects against nonalcoholic fatty liver disease in young rats via activating telomerase and inhibiting apoptosis

Non-alcoholic fatty liver disease (NAFLD) is becoming one of the world's most common chronic liver diseases in childhood, yet no therapy is available that has been approved by the food and drug administration (FDA). Previous studies have reported that telomere and telomerase are involved the development and progression of NAFLD. This study was designed to investigate the potential beneficial effects of activated carbon N-acetylcysteine (ACNAC) microcapsules on the development of NAFLD in young rats as well as the underlying mechanism(s) involved. Three-week old male Sprague Dawley rats were given high-fat diet (HFD) with/without ACNAC treatment for 7 consecutive weeks. Liver pathologies were determined by hematoxylin and eosin (H&E) and Oil Red O staining, as well as by changes in biochemical parameters of plasma alanine transaminase (ALT) and aspartate transaminase (AST) levels, respectively. Glucose homeostasis was evaluated by the glucose tolerance test and the liver telomere length and activity were measured by real time PCR and telomeric repeat amplification protocol (TRAP). Western blot analysis was performed to determine the expression level of Bcl-2, Bax and Caspase-3. Our results demonstrated that ACNAC supplementation improved liver pathologies of rats that received long-term HFD feeding. ACNAC supplementation prevented HFD-induced telomere shortening and improved telomerase activity. Moreover, in comparison to HFD-fed rats, ACNAC supplementation markedly increased the expression of Bcl-2, but significantly decreased the expression of Bax and Caspase-3 in juvenile rats. Together, these results indicate that ACNAC may be a promising choice for preventing and treating NAFLD among children.

Protein inhibitor of activated STAT 4 (PIAS4) regulates pro-inflammatory transcription in hepatocytes by repressing SIRT1

Excessive nutrition promotes the pathogenesis of non-alcoholic steatohepatitis (NASH), characterized by the accumulation of pro-inflammation mediators in the liver. In the present study we investigated the regulation of pro-inflammatory transcription in hepatocytes by protein inhibitor of activated STAT 4 (PIAS4) in this process and the underlying mechanisms. We report that expression of the class III deacetylase SIRT1 was down-regulated in the livers of NASH mice accompanied by a simultaneous increase in the expression and binding activity of PIAS4. Exposure to high glucose stimulated the expression PIAS4 in cultured hepatocytes paralleling SIRT1 repression. Estrogen, a known NASH-protective hormone, ameliorated SIRT1 trans-repression by targeting PIAS4. Over-expression of PIAS4 enhanced, while PIAS4 knockdown alleviated, repression of SIRT1 transcription by high glucose. Lentiviral delivery of short hairpin RNA (shRNA) targeting PIAS4 attenuated hepatic inflammation in NASH mice by restoring SIRT1 expression. Mechanistically, PIAS4 promoted NF-κB-mediated pro-inflammatory transcription in a SIRT1 dependent manner. In conclusion, our study indicates that PIAS4 mediated SIRT1 repression in response to nutrient surplus contributes to the pathogenesis of NASH. Therefore, targeting PIAS4 might provide novel therapeutic strategies in the intervention of NASH.

Developmental Origins of Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Its prevalence is currently increasing not only in developed obese countries but also in developing countries. Recent findings from human cohorts and animal studies suggest that a nutritional imbalance in the early critical period is causatively associated with the incidence of NAFLD in later life. Based on the current theory of the developmental origins of health and disease (DOHaD), undernourishment and overnourishment in utero are both hypothesized to prime the predisposition for hepatic fat storage. Current knowledge on the developmental origins of NAFLD is introduced in this chapter.

Interferon lambda 4 rs368234815 TT>δG variant is associated with liver damage in patients with nonalcoholic fatty liver disease

The interferon (IFN) lambda 3/4 (IFNL3/4) locus, influencing innate immunity regulation, has been associated with the severity of hepatitis and fibrosis progression during chronic hepatitis C infection, while contrasting results were reported in nonalcoholic fatty liver disease. In this study, we examined whether rs12979860 and the linked causal rs368234815 variant encoding for the alternative IFNL4 protein variant are associated with liver fibrosis and damage in a large multicenter cohort of patients at risk of nonalcoholic steatohepatitis. To clarify the mechanism, we also evaluated the impact on IFN-stimulated gene hepatic expression in a subset of patients. We considered 946 consecutive Italian individuals at risk of nonalcoholic steatohepatitis with liver histology evaluated according to Kleiner. The rs368234815 TT>δG, rs12979860 C>T, and patatin-like phospholipase-3 rs738409 C>G polymorphisms were genotyped; and IFN-stimulated gene hepatic expression (n = 16) was tested by TaqMan assays. We found that the rs368234815 TT allele was independently associated with severe F3-F4 fibrosis (odds ratio, 1.53; 95% confidence interval, 1.15-2.31; P = 0.005) and with severe (grade 2-3) lobular necroinflammation (odds ratio, 1.47; 95% confidence interval, 1.14-1.88; P = 0.002). The impact of rs368234815 on liver damage was generally more marked in nonobese individuals, where association with severe fibrosis, necroinflammation, and nonalcoholic steatohepatitis was observed (P < 0.05). IFN-stimulated genes were hypo-expressed in the liver of patients carrying the IFNL4 rs368234815 TT/TT genotype (P < 0.05). Similar results were observed when considering the rs12979860 polymorphism, which was in high linkage disequilibrium with rs368234815 (R² = 0.87).

CONCLUSION

The IFNL4 genotype is associated with severity of fibrosis in nonalcoholic fatty liver disease patients of European ancestry, likely by modulating the activation of innate immunity and necroinflammation. (Hepatology 2017;66:1885-1893).

Molecular mechanisms of nonalcoholic fatty liver disease: Potential role for 12-lipoxygenase

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of pathologies associated with fat accumulation in the liver. NAFLD is the most common cause of liver disease in the United States, affecting up to a third of the general population. It is commonly associated with features of metabolic syndrome, particularly insulin resistance. NAFLD shares the basic pathogenic mechanisms with obesity and insulin resistance, such as mitochondrial, oxidative and endoplasmic reticulum stress. Lipoxygenases catalyze the conversion of poly-unsaturated fatty acids in the plasma membrane-mainly arachidonic acid and linoleic acid-to produce oxidized pro-inflammatory lipid intermediates. 12-Lipoxygenase (12-LOX) has been studied extensively in setting of inflammation and insulin resistance. As insulin resistance is closely associated with development of NAFLD, the role of 12-LOX in pathogenesis of NAFLD has received increasing attention in recent years. In this review we discuss the role of 12-LOX in NAFLD pathogenesis and its potential role in emerging new therapeutics.

Association of single nucleotide polymorphism at PNPLA3 with fatty liver, steatohepatitis, and cirrhosis of liver

BACKGROUND/PURPOSE

The aim of this study was to determine the association of single nucleotide polymorphism (SNP) in patatin-like phospholipase domain-containing 3 (PNPLA3) at I148 with histological severity of non-alcoholic fatty liver disease (NAFLD).

METHODS

Patients were selected for the study if they had histological evidence of NAFLD and clinical evidence of non-alcoholic steatohepatits (NASH) cirrhosis. We included 50 NASH cirrhosis, 99 patients of NAFLD including 36 non-NASH fatty liver (NNFL) along with 63 NASH and 75 healthy controls. PNPLA3 genotyping was done by real-time PCR using a Taqman assay for rs738409.

RESULTS

CC, CG, and GG frequencies were 45 (60.0%)/27 (36.0%)/3 (4.0%) in healthy control, 19 (52.8%)/14 (38.9%)/ 3 (8.3%) in NNFL, 18 (28.6%)/29 (46.0%)/16 (25.4%) in NASH, and 7 (14.6%), 25 (52.1%), 16 (33.3%) in cirrhosis. The frequency of G allele was significantly higher (62.6%) in NAFLD than in healthy control. The GG genotype had 20.25 times odds of NAFLD. The GG genotype had 6.53 times odds of having NASH. HOMA-IR > 1.6 had 3.81 times odds of having NASH. Regression analysis revealed that G allele odds of having cirrhosis was 3.9 times compared to C. The G allele was also significantly associated with steatosis, lobular inflammation, NAFLD activity score, and fibrosis.

CONCLUSION

PNPLA3 genotype showed an association with NAFLD, NASH, fibrosis, and cirrhosis.

Clinical endpoints and adaptive clinical trials in precirrhotic nonalcoholic steatohepatitis: Facilitating development approaches for an emerging epidemic

Due to the increasing prevalence of nonalcoholic steatohepatitis (NASH) and its associated health burden, there is a high need to develop therapeutic strategies for patients with this disease. Unfortunately, its long and asymptomatic natural history, the uncertainties about disease progression, the fact that most patients are undiagnosed, and the requirement for sequential liver biopsies create substantial challenges for clinical development. Adaptive design methods are increasingly used in clinical research as they provide the flexibility and efficiency for identifying potential signals of clinical benefit of the test treatment under investigation and make prompt preplanned adaptations without undermining the validity or integrity of the trial. Given the high unmet medical need and the lack of validated surrogate endpoints in NASH, the use of adaptive design methods appears reasonable. Furthermore, due to the limited number of patients willing to have multiple liver biopsies and the need for long‐term exposure to assess an impact in outcomes, a continuous seamless adaptive design may reduce the overall sample size while allowing patients to continue after each one of the phases. Here, we review strategic frameworks that include potential surrogate endpoints as well as statistical and logistical approaches that could be considered for applying adaptive designs to clinical trials in NASH with the goal of facilitating drug development for this growing medical need. (Hepatology Communications 2017;1:577–585)

Extracts of Salvia-Nelumbinis Naturalis Ameliorate Nonalcoholic Steatohepatitis via Inhibiting Gut-Derived Endotoxin Mediated TLR4/NF-κB Activation

Nonalcoholic steatohepatitis (NASH) is featured by the presence of hepatic steatosis combined with inflammation and hepatocellular injury. Gut-derived endotoxin plays a crucial role in the pathogenesis of NASH. Salvia-Nelumbinis naturalis (SNN), a formula of Traditional Chinese Medicine, has been identified to be effective for NASH, but the mechanisms were not thoroughly explored. In the present study, a NASH model was generated using C57BL/6 mice fed a high fat diet (HFD) supplemented periodically with dextran sulfate sodium (DSS) in drinking water for 12 weeks. Mice fed HFD alone (without DSS) or chow diet were used as controls. The NASH mice were given the SNN extracts in the following 4 weeks, while control mice were provided with saline. Mice fed HFD developed steatosis, and DSS supplementation resulted in NASH. The SNN extracts significantly improved metabolic disorders including obesity, dyslipidemia, and liver steatosis and reduced hepatic inflammation, circulating tumor necrosis factor-α (TNF-α), and lipopolysaccharide (LPS) levels. The beneficial effect of the SNN extracts was associated with restoration of intestinal conditions (microbiota, integrity of intestinal barrier) and inhibition of TLR4/NF-κB activation. These results suggest that the SNN extracts ameliorate NASH progression, possibly through blocking endotoxin related TLR4/NF-κB activation.

Emerging roles of SIRT1 in fatty liver diseases

Fatty liver diseases, which are commonly associated with high-fat/calorie diet, heavy alcohol consumption and/or other metabolic disorder causes, lead to serious medical concerns worldwide in recent years. It has been demonstrated that metabolic homeostasis disruption is most likely to be responsible for this global epidemic. Sirtuins are a group of conserved nicotinamide adenine dinucleotide (NAD⁺) dependent histone and/or protein deacetylases belonging to the silent information regulator 2 (Sir2) family. Among seven mammalian sirtuins, sirtuin 1 (SIRT 1) is the most extensively studied one and is involved in both alcoholic and nonalcoholic fatty liver diseases. SIRT1 plays beneficial roles in regulating hepatic lipid metabolism, controlling hepatic oxidative stress and mediating hepatic inflammation through deacetylating some transcriptional regulators against the progression of fatty liver diseases. Here we summarize the latest advances of the biological roles of SIRT1 in regulating lipid metabolism, oxidative stress and inflammation in the liver, and discuss the potential of SIRT1 as a therapeutic target for treating alcoholic and nonalcoholic fatty liver diseases.

Insulin resistance promotes Lysyl Oxidase Like 2 induction and fibrosis accumulation in non-alcoholic fatty liver disease

In patients with non-alcoholic fatty liver disease (NAFLD), insulin resistance (IR) associates with fibrosis progression independently of the hepatic inflammation, but the mechanisms are still unclear. We modeled the independent contribution of inflammation (non-alcoholic steatohepatitis: NASH) by exploiting the methionine-choline deficient (MCD) diet, and that of IR by insulin receptor (InsR) haploinsufficiency (InsR+/-) in the pathogenesis of liver fibrosis in C57BL/6 mice. We confirmed the study findings in 96 patients with NAFLD. InsR+/- enhanced hepatic fat content and impaired hepatic insulin signaling leading to Forkhead box protein O1 (FoxO1) accumulation in MCD-fed mice. Remarkably, despite reduced inflammation and hampered transdifferentiation of hepatic stellate cells (HSCs), InsR+/- promoted hepatic fibrosis accumulation, which correlated with the induction of the Lysyl Oxidase Like 2 (Loxl2), involved in matrix stabilization. Loxl2 up-regulation was not a cell autonomous property of insulin resistant HSCs, but was dependent on microparticles (MPs) released specifically by insulin resistant hepatocytes (HEPs) exposed to fatty acids. The mechanism entailed FoxO1 up-regulation, as FoxO1 silencing normalized Loxl2 expression reversing fibrosis in InsR+/- MCD-fed mice. Loxl2 up-regulation was similarly detected during IR induced by obesity, but not by lipogenic stimuli (fructose feeding). Most importantly, LOXL2 up-regulation was observed in NAFLD patients with type 2 diabetes (T2D) and LOXL2 hepatic and circulating levels correlated with histological fibrosis progression. IR favors fibrosis deposition independently of the classic 'inflammation - HSC transdifferentiation' pathway. The mechanism entails a cross-talk between enhanced lipotoxicity in insulin resistant HEPs and Loxl2 production by HSCs, which was confirmed in patients with diabetes, thereby facilitating extracellular matrix (ECM) stabilization.

NAFLD as a Sexual Dimorphic Disease: Role of Gender and Reproductive Status in the Development and Progression of Nonalcoholic Fatty Liver Disease and Inherent Cardiovascular Risk

Nonalcoholic fatty liver disease (NAFLD) spans steatosis through nonalcoholic steatohepatis, cirrhosis, and hepatocellular carcinoma (HCC) associated with striking systemic features and excess cardiovascular and liver-related mortality. The pathogenesis of NAFLD is complex and multifactorial. Endocrine derangements are closely linked with dysmetabolic traits. For example, in animal and human studies, female sex is protected from dysmetabolism thanks to young individuals' ability to partition fatty acids towards ketone body production rather than very low density lipoprotein (VLDL)-triacylglycerol, and to sex-specific browning of white adipose tissue. Ovarian senescence facilitates both the development of massive hepatic steatosis and the fibrotic progression of liver disease in an experimental overfed zebrafish model. Consistently, estrogen deficiency, by potentiating hepatic inflammatory changes, hastens the progression of disease in a dietary model of nonalcoholic steatohepatitis (NASH) developing in ovariectomized mice fed a high-fat diet. In humans, NAFLD more often affects men; and premenopausal women are equally protected from developing NAFLD as they are from cardiovascular disease. It would be expected that early menarche, definitely associated with estrogen activation, would produce protection against the risk of NAFLD. Nevertheless, it has been suggested that early menarche may confer an increased risk of NAFLD in adulthood, excess adiposity being the primary culprit of this association. Fertile age may be associated with more severe hepatocyte injury and inflammation, but also with a decreased risk of liver fibrosis compared to men and postmenopausal status. Later in life, ovarian senescence is strongly associated with severe steatosis and fibrosing NASH, which may occur in postmenopausal women. Estrogen deficiency is deemed to be responsible for these findings via the development of postmenopausal metabolic syndrome. Estrogen supplementation may at least theoretically protect from NAFLD development and progression, as suggested by some studies exploring the effect of hormonal replacement therapy on postmenopausal women, but the variable impact of different sex hormones in NAFLD (i.e., the pro-inflammatory effect of progesterone) should be carefully considered.

Current Concepts in Pediatric Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of disease. Its increasing prevalence is a direct result of historically high rates of obesity. Hepatocyte lipid accumulation is the first step in a cascade of metabolic and inflammatory events thought to precipitate NAFLD. Histologic findings provide insight into these events. Lifestyle modification remains the primary therapy in children. Current recommendations include vitamin E treatment in those with biopsy-proven NASH. Trials of novel drugs are ongoing in adults. As efficacy/safety are established, these therapies may be tenable for use in children. At the current time, biopsy-driven histology endpoints are necessary to establish whether future therapies can improve pediatric or adult-type NASH in children.

Nonalcoholic fatty liver disease and bariatric surgery: a comprehensive review

CONTEXT AND OBJECTIVE:

Nonalcoholic fatty liver disease (NAFLD) has been increasingly diagnosed worldwide and is now recognized as a source of public health concern. It comprises a wide spectrum of histological features that range from simple steatosis to severe forms of fibrosis, steatohepatitis and even cirrhosis. The impact of bariatric surgery on the course of NAFLD in individuals with obesity has been extensively studied.

DESIGN AND SETTING:

Narrative review; public university hospital.

METHODS:

A comprehensive review was conducted based on an online search on the electronic databases MEDLINE and LILACS using the MeSH terms "fatty liver" and "bariatric surgery".

RESULTS:

The exact mechanisms that lead to improvement in NAFLD following bariatric surgery are not completely understood. Since Roux-en-Y gastric bypass (RYGB) is the bariatric surgical procedure most performed worldwide, it is also the one from which the effects on NAFLD have been most studied, although there is also consistent evidence regarding the effects from gastric banding, sleeve gastrectomy and biliopancreatic diversions.

CONCLUSION:

According to the currently available evidence, bariatric surgery leads to significant improvement in NAFLD. Further research, especially by means of randomized controlled trials enrolling larger cohorts of individuals, is needed to determine the optimal procedure for this group of subjects.

Gastrointestinal Complications of Obesity

Obesity usually is associated with morbidity related to diabetes mellitus and cardiovascular diseases. However, there are many gastrointestinal and hepatic diseases for which obesity is the direct cause (eg, nonalcoholic fatty liver disease) or is a significant risk factor, such as reflux esophagitis and gallstones. When obesity is a risk factor, it may interact with other mechanisms and result in earlier presentation or complicated diseases. There are increased odds ratios or relative risks of several gastrointestinal complications of obesity: gastroesophageal reflux disease, erosive esophagitis, Barrett's esophagus, esophageal adenocarcinoma, erosive gastritis, gastric cancer, diarrhea, colonic diverticular disease, polyps, cancer, liver disease including nonalcoholic fatty liver disease, cirrhosis, hepatocellular carcinoma, gallstones, acute pancreatitis, and pancreatic cancer. Gastroenterologists are uniquely poised to participate in the multidisciplinary management of obesity as physicians caring for people with obesity-related diseases, in addition to their expertise in nutrition and endoscopic interventions.

Role of folate in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of chronic liver conditions that are characterized by steatosis, inflammation, fibrosis, and liver injury. The global prevalence of NAFLD is rapidly increasing in proportion to the rising incidence of obesity and type 2 diabetes. Because NAFLD is a multifaceted disorder with many underlying metabolic abnormalities, currently, there is no pharmacological agent that is therapeutically approved for the treatment of this disease. Folate is a water-soluble B vitamin that plays an essential role in one-carbon transfer reactions involved in nucleic acid biosynthesis, methylation reactions, and sulfur-containing amino acid metabolism. The liver is the primary organ responsible for storage and metabolism of folates. Low serum folate levels have been observed in patients with obesity and diabetes. It has been reported that a low level of endogenous folates in rodents perturbs folate-dependent one-carbon metabolism, and may be associated with development of metabolic diseases such as NAFLD. This review highlights the biological role of folate in the progression of NAFLD and its associated metabolic complications including obesity and type 2 diabetes. Understanding the role of folate in metabolic disease may position this vitamin as a potential therapeutic for NAFLD.

Morbidity and mortality associated with obesity

Obesity and its repercussions constitute an important source of morbidity, impaired quality of life and its complications can have a major bearing on life expectancy. The present article summarizes the most important co-morbidities of obesity and their prevalence. Furthermore, it describes classification and grading systems that can be used to assess the individual and combined impact of co-morbid conditions on mortality risk. The literature was screened for assessment tools that can be deployed in the quantification of morbidity and mortality risk in individual patients. Thirteen specific domains have been identified that account for morbidity and mortality in obesity. Cardiovascular disease (CVD) and cancer account for the greatest mortality risk associated with obesity. The King's Criteria and Edmonton Obesity Staging System (EOSS) were identified as useful tools for the detection and monitoring of individual patient mortality risk in obesity care. The stark facts on the complications of obesity should be capitalized on to improve patient management and knowledge and referred to in the wider dissemination of public health messages aimed at improving primary prevention.

Inhibition of sphingosine 1-phosphate signaling ameliorates murine nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a lipotoxic disorder, wherein proinflammatory lipids, such as ceramide and its derivative sphingosine 1-phosphate (S1P), contribute to macrophage-associated liver inflammation. For example, we have previously demonstrated a role for S1P in steatotic hepatocyte-derived S1P-enriched extracellular vesicles in macrophage chemotaxis in vitro. Therefore, we hypothesized that FTY720, an S1P antagonist, would ameliorate NASH by inhibiting proinflammatory monocyte chemotaxis. To test our hypothesis, NASH was established in C57BL/6 male mice by feeding a diet high in fructose, saturated fat, and cholesterol for 22 wk. Then mice received daily intraperitoneal injections of FTY720 for 2 wk before analysis of liver injury, inflammation, and fibrosis. FTY720-treated mice with NASH demonstrated improved liver histology with a significant reduction in hepatocyte ballooning and inflammatory foci. Hepatomegaly was reversed, and liver triglycerides were reduced following FTY720 administration to mice with NASH. Correspondingly, serum ALT levels, hepatic inflammatory macrophage accumulation, and the expression of Ly6C in recruited myeloid cells was reduced in FTY720-treated mice. Hepatic collagen accumulation and expression of α-smooth muscle actin were significantly lowered as well. Body composition, energy consumption and utilization, and hepatic sphingolipid composition remained unchanged following FTY720 administration. FTY720 ameliorates murine nonalcoholic steatohepatitis. Reduction in liver injury and inflammation is associated with a reduction in hepatic macrophage accumulation, likely due to dampened recruitment of circulating myeloid cells into the liver. Nonalcoholic steatohepatitis may be a novel indication for the therapeutic use of FTY720.NEW & NOTEWORTHY There are no approved pharmacologic therapies for nonalcoholic steatohepatitis (NASH), the leading cause of chronic liver disease worldwide. This study describes the use of FTY720, a novel small molecule, for the amelioration of NASH in a mouse model. We demonstrate that 2-wk administration of FTY720 to mice with NASH led to a reduction in liver injury, inflammation, and fibrosis. These data provide a preclinical rationale for studying this drug in human NASH.

Nonalcoholic fatty liver disease: What do we know and what will we have to learn?

The article reviews relevant data on the prevalence, natural history, pathogenesis, diagnosis, and treatment of nonalcoholic fatty liver disease and critically assesses the fixed notion of this disease.

The Effects of Metabolic Surgery on Fatty Liver Disease and Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is an under-recognized but increasingly important manifestation of the metabolic syndrome. Bariatric surgery, both through direct weight loss and more indirect effects on insulin resistance and improvements in inflammatory proteins, can have a profound effect on NAFLD, resulting in improvement or resolution of even high-grade liver disease.

The epidemiology of non-alcoholic fatty liver disease

The increase in Non-alcoholic Fatty Liver Disease (NAFLD) and the imminent disappearance of chronic viral hepatitis thanks to new and effective therapies is motivating hepatologists to change their clinical approach to chronic liver disease. NAFLD-cirrhosis or NAFLD-Hepatocellular Carcinoma (HCC) are now the second cause of liver transplantation in the USA. This short-review is focused to the epidemiology of NAFLD/Non-alchoholic Steatohepatitis (NASH), including the definition of this disease which should be revised as well discussing the prevalence, risk factors for progression, natural history and mortality. NAFLD is considered to be the hepatic manifestation of the metabolic syndrome (MS). It affects 25-30% of the general population and the risk factors are almost identical to those of MS. The natural history involves either the development of cardiovascular diseases or cirrhosis and HCC. HCC can also develop in NASH in the absence of cirrhosis (45% of cases). We conclude that an international consensus conference on the definition, natural history, policies of surveillance and new pharmacological treatments of NAFLD and NASH is urgently needed.

Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) comprises a disease spectrum ranging from benign hepatic steatosis to non-alcoholic steatohepatitis with inflammation (NASH) and liver cirrhosis. NAFLD is now recognised as the hepatic manifestation of the metabolic syndrome. Simple steatosis is benign, whereas NASH can progress to cirrhosis with its resultant complications. Liver biopsy remains the gold standard in the diagnosis of NAFLD/NASH. Lifestyle and dietary modifications to achieve sustained weight loss is the cornerstone of NAFLD/NASH treatment.

Association of HFE gene C282Y and H63D mutations with liver cirrhosis in the Lithuanian population

BACKGROUND AND OBJECTIVE

Liver cirrhosis is the end-stage disease of chronic liver injury. Due to differences in the natural course of chronic liver diseases, identification of genetic factors that influence individual outcomes is warranted. HFE-linked hereditary hemochromatosis (HH) predisposes disease progression to cirrhosis; however, the role of heterozygous C282Y or H63D mutations in the development of cirrhosis in the presence of other etiological factors is still debated. The aim of this study was to determine the association between heterozygous C282Y and H63D mutations and non-HH liver cirrhosis in Lithuanian population.

MATERIALS AND METHODS

The patient cohort consisted of 209 individuals. Diagnosis of cirrhosis was confirmed by clinical, laboratory parameters, liver biopsy, and radiological imaging. Control samples were obtained from 1005 randomly selected unrelated healthy individuals. HFE gene mutations were determined using the PCR-RFLP method.

RESULTS

The most common causes of cirrhosis were hepatitis C (33.9%), hepatitis B (13.6%), and alcohol (25.8%). C282Y allele was associated with the presence of cirrhosis (OR=2.07; P=0.005); this was also observed under recessive model for C282Y (OR=2.06, P=0.008). The prevalence of C282Y allele was higher in cirrhotic men than in controls (7.0% vs. 2.8%, P=0.002). The carriage of H63D risk allele (OR=1.54; P=0.02), heterozygous C282Y/wt and homozygous H63D/H63D genotypes were associated with liver cirrhosis in males (OR=2.48, P=0.008, and OR=4.13, P=0.005, respectively).

CONCLUSIONS

Heterozygous C282Y mutation of the HFE gene was associated with liver cirrhosis in the Lithuanian population. In gender-related analysis, heterozygous C282Y and homozygous H63D mutations were linked to liver cirrhosis in men, not in women.

Clinical significance of serum Wisteria floribunda agglutinin positive Mac-2-binding protein level in non-alcoholic steatohepatitis

AIM

To examine the relationship between the Wisteria floribunda agglutinin positive Mac-2-binding protein (WFA+ -M2BP) level and histological findings for patients with non-alcoholic steatohepatitis (NASH).

METHODS

A total of 134 NASH patients (mean age, 51.7 years) were analyzed. We examined the effect of WFA+ -M2BP level on severity of liver fibrosis comparing with other laboratory markers, including aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio, AST to platelet ratio index (APRI), FIB-4 index, platelet count and hyaluronic acid as serum liver fibrosis markers. Receiver-operator curve (ROC) analysis was performed for calculating the area under the ROC (AUROC).

RESULTS

The WFA+ -M2B P-value ranged from 0.2 cut-off index (COI) to 9.6 COI (median, 0.9). The median values in each fibrosis stage were: 0.7 COI in F1, 0.7 COI in F2, 1.2 COI in F3 and 2.4 COI in F4 (P < 0.001). For predicting liver cirrhosis (F4), WFA+ -M2BP level had the AUROC of 0.854 (sensitivity, 69.2%; specificity, 88.4%) and for predicting advanced liver fibrosis (≥F3), WFA+ -M2BP level yielded the second highest AUROC with a level of 0.842 (sensitivity, 73.7%; specificity, 80.2%) and for predicting significant liver fibrosis (≥F2), WFA+ -M2BP level yielded the highest AUROC with a level of 0.663 (sensitivity, 47.2%; specificity, 78.6%) among six liver fibrosis markers. The median values in patients with ballooning scores 1 (n = 58) and 2 (n = 76) were 0.6 and 1.1 COI, respectively (P < 0.001).

CONCLUSION

Serum WFA+ -M2BP level can be useful for assessing liver histological findings in patients with NASH.

Lipotoxic lethal and sublethal stress signaling in hepatocytes: relevance to NASH pathogenesis

The accumulation of lipids is a histologic and biochemical hallmark of obesity-associated nonalcoholic fatty liver disease (NAFLD). A subset of NALFD patients develops progressive liver disease, termed nonalcoholic steatohepatitis, which is characterized by hepatocellular apoptosis and innate immune system-mediated inflammation. These responses are orchestrated by signaling pathways that can be activated by lipids, directly or indirectly. In this review, we discuss palmitate- and lysophosphatidylcholine (LPC)-induced upregulation of p53-upregulated modulator of apoptosis and cell-surface expression of the death receptor TNF-related apoptosis-inducing ligand receptor 2. Next, we review the activation of stress-induced kinases, mixed lineage kinase 3, and c-Jun N-terminal kinase, and the activation of endoplasmic reticulum stress response and its downstream proapoptotic effector, CAAT/enhancer binding homologous protein, by palmitate and LPC. Moreover, the activation of these stress signaling pathways is linked to the release of proinflammatory, proangiogenic, and profibrotic extracellular vesicles by stressed hepatocytes. This review discusses the signaling pathways induced by lethal and sublethal lipid overload that contribute to the pathogenesis of NAFLD.

Nonalcoholic fatty liver disease: one entity, multiple impacts on liver health

Nonalcoholic fatty liver disease (NAFLD) is very prevalent and now considered the most common cause of chronic liver disease. Staging the severity of liver damage is very important because the prognosis of NAFLD is highly variable. The long-term prognosis of patients with NAFLD remains incompletely elucidated. Even though the annual fibrosis progression rate is significantly higher in patients with nonalcoholic hepatitis (NASH), both types of NAFLD (nonalcoholic fatty liver and nonalcoholic steatohepatitis) can lead to fibrosis. The risk for progressive liver damage and poor outcomes is assessed by staging the severity of liver injury and liver fibrosis. Algorithms (scores) that incorporate various standard clinical and laboratory parameters alongside imaging-based approaches that assess liver stiffness are helpful in predicting advanced fibrosis.

Ezetimibe reduced hepatic steatosis induced by dietary oxysterols in nonhuman primates

Oxidized cholesterol (oxysterols) plays an important and multifaceted role in lipid metabolism. Here we examined whether dietary oxysterols accelerate hepatic lipid accumulation and inflammation in nonhuman primates. We also examined the effect of the Niemann–Pick C1‐like1 inhibitor, ezetimibe (Ez). Macaca fascicularis (5‐year‐old males) were fed either regular cholesterol + high‐fat diet (control‐HFD) or oxysterols + high‐fat diet (ox‐HFD; with 0.015% of oxysterols cholesterol) for 24 weeks. Compared with control‐HFD, ox‐HFD did not affect plasma lipid levels, but it did affect hepatic lipid levels [total cholesterol, 40.9 mg·g⁻¹ (ox‐HFD) versus 3.2 (control‐HFD) mg·g⁻¹; triglycerides, 28.0 (ox‐HFD) versus 5.7 (control‐HFD) mg·g⁻¹]. Ox‐HFD increased lipid accumulation as well as recruitment of inflammatory cells when compared to control‐HFD. We then examined the effects of Ez, 0.2 mg·kg⁻¹·day⁻¹ for 12 weeks. In addition to a significant reduction in dyslipidemia, Ez alleviated biochemical and pathological aspects of steatosis. Dietary oxysterols aggravate steatosis in nonhuman primates. Treatment with Ez may be a novel therapeutic approach to NAFLD by alleviating dyslipidemia.

Sevelamer Improves Steatohepatitis, Inhibits Liver and Intestinal Farnesoid X Receptor (FXR), and Reverses Innate Immune Dysregulation in a Mouse Model of Non-alcoholic Fatty Liver Disease

Bile acid sequestrants are synthetic polymers that bind bile acids in the gut and are used to treat dyslipidemia and hyperphosphatemia. Recently, these agents have been reported to lower blood glucose and increase insulin sensitivity by altering bile acid signaling pathways. In this study, we assessed the efficacy of sevelamer in treating mice with non-alcoholic fatty liver disease (NAFLD). We also analyzed how sevelamer alters inflammation and bile acid signaling in NAFLD livers. Mice were fed a low-fat or Western diet for 12 weeks followed by a diet-plus-sevelamer regimen for 2 or 12 weeks. At the end of treatment, disease severity was assessed, hepatic leukocyte populations were examined, and expression of genes involved in farnesoid X receptor (FXR) signaling in the liver and intestine was analyzed. Sevelamer treatment significantly reduced liver steatosis and lobular inflammation. Sevelamer-treated NAFLD livers had notably fewer pro-inflammatory infiltrating macrophages and a significantly greater fraction of alternatively activated Kupffer cells compared with controls. Expression of genes involved in FXR signaling in the liver and intestine was significantly altered in mice with NAFLD as well as in those treated with sevelamer. In a mouse model of NAFLD, sevelamer improved disease and counteracted innate immune cell dysregulation in the liver. This study also revealed a dysregulation of FXR signaling in the liver and intestine of NAFLD mice that was counteracted by sevelamer treatment.

Effects of Omega-3 Fatty Acid in Nonalcoholic Fatty Liver Disease: A Meta-Analysis

A meta-analysis was conducted to assess the effect of omega-3 fatty acid supplementation (n-3 PUFAs) in lowering liver fat, liver enzyme (alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT) levels), and blood lipids (triglyceride (TG), total cholesterol (TC), high density lipoprotein (HDL), and low density lipoprotein (LDL)) in patients with nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH). Methods. MEDLINE/PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, CINAHL, Science Citation Index (ISI Web of Science), Chinese Biomedical Literature Database (CBM), and Chinese National Knowledge Infrastructure (CNKI) were searched for relevant randomized controlled trials on the effects of n-3 polyunsaturated fatty acids (PUFAs) in patients with NAFLD from inception to May 2015. Ten studies were included in this meta-analysis. Results. 577 cases of NAFLD/NASH in ten randomized controlled trials (RCTs) were included. The results of the meta-analysis showed that benefit changes in liver fat favored PUFA treatment, and it was also beneficial for GGT, but it was not significant on ALT, AST, TC, and LDL. Conclusions. In this meta-analysis, omega-3 PUFAs improved liver fat, GGT, TG, and HDL in patients with NAFLD/NASH. Therefore, n-3 PUFAs may be a new treatment option for NAFLD.

Suppression of IGF binding protein-3 by palmitate promotes hepatic inflammatory responses

IGF-binding protein-3 (IGFBP-3) is a liver-derived, anti-inflammatory molecule that is decreased in obesity, a key risk factor for nonalcoholic fatty liver disease (NAFLD). It was not known whether IGFBP-3 levels were altered in NAFLD, whether such alterations could be the result of lipotoxicity, and whether altered IGFBP-3 could affect pathways that are involved in hepatic and systemic inflammation. Serum IGFBP-3 was decreased in patients with NAFLD, whereas liver and circulating IL-8 levels were increased. Palmitate inhibited IGFBP-3 secretion by THP-1 macrophages and enhanced IL-8 expression. Exposure of palmitate-treated THP-1 macrophages to IGFBP-3-deficient conditioned medium led to a 20-fold increase in palmitate-induced IL-8 expression by hepatocytes. Conversely, overexpression of IGFBP-3 suppressed JNK and NF-κB activation and blocked palmitate-induced IL-8 expression in hepatocytes. Silencing IGFBP-3 in Huh7 cells enhanced JNK and NF-κB activity and increased palmitate-induced IL-8 secretion. These data indicate that IGFBP-3 serves as an anti-inflammatory brake in hepatocytes against JNK and NF-κB and limits their activation and downstream production of proinflammatory cytokines. Under lipotoxic conditions, palmitate inhibits hepatic macrophage secretion of IGFBP-3, thereby releasing the brake and enhancing palmitate-induced IL-8 synthesis and secretion.-Min, H.-K., Maruyama, H., Jang, B. K., Shimada, M., Mirshahi, F., Ren, S., Oh, Y., Puri, P., Sanyal, A. J. Suppression of IGF binding protein-3 by palmitate promotes hepatic inflammatory responses.

Protein inhibitor of activated STAT 4 (PIAS4) regulates liver fibrosis through modulating SMAD3 activity

Excessive fibrogenesis disrupts normal liver structure, impairs liver function, and precipitates the development of cirrhosis, an irreversible end-stage liver disease. A host of factors including nutrition surplus contribute to liver fibrosis but the underlying mechanism is not fully understood. In the present study, we investigated the involvement of protein inhibitor for activated stat 4 (PIAS4) in liver fibrosis in a mouse model of non-alcoholic steatohepatitis (NASH). We report that PIAS4 silencing using short hairpin RNA (shRNA) attenuated high-fat high-carbohydrate (HFHC) diet induced liver fibrosis in mice. Quantitative PCR and Western blotting analyses confirmed that PIAS4 knockdown downregulated a panel of pro-fibrogenic genes including type I and type III collagens, smooth muscle actin, and tissue inhibitors of metalloproteinase. Mechanistically, PIAS4 silencing blocked the recruitment of SMAD3, a potent pro-fibrogenic transcription factor, to the promoter regions of pro-fibrogenic genes and dampened SMAD3 acetylation likely by upregulating SIRT1 expression. In conclusion, PIAS4 may contribute to liver fibrosis by modulating SIRT1-dependent SMAD3 acetylation.

Pharmacological management of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) affects one-third of the population and two-thirds of patients with obesity or type 2 diabetes (T2DM). Its more aggressive form is known as nonalcoholic steatohepatitis (NASH) and is characterized by hepatocyte necrosis, inflammation and often fibrosis. The presence of fibrosis indicates a more aggressive course and may lead to cirrhosis. Premature mortality in NASH is related to both hepatic (cirrhosis and hepatocellular carcinoma) and extra-hepatic complications, largely cardiovascular disease (CVD). Many therapeutic agents have been tested, but still none approved specifically for NASH. Treatment of NAFLD includes aggressive management of diabetes and cardiovascular risk factors, although the role of controlling hyperglycemia per se in patients with T2DM and NASH remains unknown. Agents tested with some success in non-diabetic patients with NASH include pioglitazone, liraglutide, vitamin E and to a lesser degree, pentoxiphylline. In patients with T2DM and NASH only pioglitazone has shown to significantly improve liver histology, with only a handful of patients with diabetes having been studied with other modalities. This review focuses on available agents for NASH to assist clinicians in the management of these complex patients. Many novel compounds are being studied and will likely make combination therapy for NASH a reality in the future.

Histopathology of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is the liver injury most often associated with disorders of insulin resistance, including obesity, diabetes and the metabolic syndrome. The term encompasses several patterns of liver injury, including a relatively benign condition of steatosis without hepatocellular injury, nonalcoholic steatohepatitis (NASH), and a pattern of zone 1 steatosis, inflammation and fibrosis mainly observed in prepubertal children. Staging and grading systems have been developed to characterize the histological changes in NAFLD, mainly as a tool for clinical research. The histological features of NAFLD across these different manifestations and the scoring systems used to evaluate disease severity are discussed.

Non-alcoholic fatty liver disease and cardiovascular risk: Pathophysiological mechanisms and implications

Non-alcoholic fatty liver disease (NAFLD) has become one of the most frequent chronic liver diseases in the Western society and its prevalence is likely to rise even further. An increasing body of evidence shows that NAFLD is not only a potentially progressive liver disease, but also has systemic consequences. More specifically, evidence points out that NAFLD has to be considered as a significant independent risk factor for subclinical and clinical cardiovascular disease (CVD). Long-term follow-up studies demonstrate cardiovascular mortality to be the most important cause of death in NAFLD patients. Moreover, ample evidence associates NAFLD with endothelial dysfunction, increased pulse wave velocity, increased coronary arterial calcifications and increased carotid intima media thickness, all established markers for CVD. Despite of all this evidence, the mechanisms by which NAFLD causally contributes to CVD are not fully elucidated. Furthermore, an extensive overview of all potential pathophysiological mechanisms and the corresponding current data are lacking. In this review we summarise current knowledge, originating from fundamental and clinical research, that mechanistically links NAFLD to CVD. Subsequently, the impact of CVD on current clinical practice and future research in the area of NALFD are discussed.

Nutritional Strategies for the Individualized Treatment of Non-Alcoholic Fatty Liver Disease (NAFLD) Based on the Nutrient-Induced Insulin Output Ratio (NIOR)

Nutrients play a fundamental role as regulators of the activity of enzymes involved in liver metabolism. In the general population, the action of nutrients may be affected by gene polymorphisms. Therefore, individualization of a diet for individuals with fatty liver seems to be a fundamental step in nutritional strategies. In this study, we tested the nutrient-induced insulin output ratio (NIOR), which is used to identify the correlation between the variants of genes and insulin resistance. We enrolled 171 patients, Caucasian men (n = 104) and women (n = 67), diagnosed with non-alcoholic fatty liver disease (NAFLD). From the pool of genes sensitive to nutrient content, we selected genes characterized by a strong response to the NIOR. The polymorphisms included Adrenergic receptor (b3AR), Tumor necrosis factor (TNFα), Apolipoprotein C (Apo C III). Uncoupling Protein type I (UCP-1), Peroxisome proliferator activated receptor γ2 (PPAR-2) and Apolipoprotein E (APOEs). We performed three dietary interventions: a diet consistent with the results of genotyping (NIOR (+)); typical dietary recommendations for NAFLD (Cust (+)), and a diet opposite to the genotyping results (NIOR (−) and Cust (−)). We administered the diet for six months. The most beneficial changes were observed among fat-sensitive patients who were treated with the NIOR (+) diet. These changes included improvements in body mass and insulin sensitivity and normalization of blood lipids. In people sensitive to fat, the NIOR seems to be a useful tool for determining specific strategies for the treatment of NAFLD.

Biochemical Scoring System for diagnosing Nonalcoholic Steatohepatitis

Noor-E-Alam M, Alam S, Alam AKMK, Al Mahtab M, Rahman S. Biochemical Scoring System for diagnosing Nonalcoholic Steatohepatitis. Euroasian J Hepato-Gastroenterol 2016;6(2):202-204.

The Relationship between Type 2 Diabetes Mellitus and Non-Alcoholic Fatty Liver Disease Measured by Controlled Attenuation Parameter

PURPOSE

The severity of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes mellitus (T2DM) population compared with that in normal glucose tolerance (NGT) individuals has not yet been quantitatively assessed. We investigated the prevalence and the severity of NAFLD in a T2DM population using controlled attenuation parameter (CAP).

MATERIALS AND METHODS

Subjects who underwent testing for biomarkers related to T2DM and CAP using Fibroscan® during a regular health check-up were enrolled. CAP values of 250 dB/m and 300 dB/m were selected as the cutoffs for the presence of NAFLD and for moderate to severe NAFLD, respectively. Biomarkers related to T2DM included fasting glucose/insulin, fasting C-peptide, hemoglobin A1c (HbA1c), glycoalbumin, and homeostasis model assessment of insulin resistance of insulin resistance (HOMA-IR).

RESULTS

Among 340 study participants (T2DM, n=66; pre-diabetes, n=202; NGT, n=72), the proportion of subjects with NAFLD increased according to the glucose tolerance status (31.9% in NGT; 47.0% in pre-diabetes; 57.6% in T2DM). The median CAP value was significantly higher in subjects with T2DM (265 dB/m) than in those with pre-diabetes (245 dB/m) or NGT (231 dB/m) (all p<0.05). Logistic regression analysis showed that subjects with moderate to severe NAFLD had a 2.8-fold (odds ratio) higher risk of having T2DM than those without NAFLD (p=0.02; 95% confidence interval, 1.21-6.64), and positive correlations between the CAP value and HOMA-IR (ρ0.407) or fasting C-peptide (ρ0.402) were demonstrated.

CONCLUSION

Subjects with T2DM had a higher prevalence of severe NAFLD than those with NGT. Increased hepatic steatosis was significantly associated with the presence of T2DM, and insulin resistance induced by hepatic fat may be an important mechanistic connection.

Transcriptional repression of SIRT1 by protein inhibitor of activated STAT 4 (PIAS4) in hepatic stellate cells contributes to liver fibrosis

Interstitial fibrosis represents a key pathological process in non-alcoholic steatohepatitis (NASH). In the liver, fibrogenesis is primarily mediated by activated hepatic stellate cells (HSCs) transitioning from a quiescent state in response to a host of stimuli. The molecular mechanism underlying HSC activation is not completely understood. Here we report that there was a simultaneous up-regulation of PIAS4 expression and down-regulation of SIRT1 expression accompanying increased hepatic fibrogenesis in an MCD-diet induced mouse model of NASH. In cultured primary mouse HSCs, stimulation with high glucose activated PIAS4 while at the same time repressed SIRT1. Over-expression of PIAS4 directly repressed SIRT1 promoter activity. In contrast, depletion of PIAS4 restored SIRT1 expression in HSCs treated with high glucose. Estrogen, a known NASH-protective hormone, antagonized HSC activation by targeting PIAS4. Lentivirus-mediated delivery of short hairpin RNA (shRNA) targeting PIAS4 in mice ameliorated MCD diet induced liver fibrosis by normalizing SIRT1 expression in vivo. PIAS4 promoted HSC activation in a SIRT1-dependent manner in vitro. Mechanistically, PIAS4 mediated SIRT1 repression led to SMAD3 hyperacetylation and enhanced SMAD3 binding to fibrogenic gene promoters. Taken together, our data suggest SIRT1 trans-repression by PIAS4 plays an important role in HSC activation and liver fibrosis.

Formulation for Effective Screening and Management of Nonalcoholic Steatohepatitis: Noninvasive NAFLD Management Strategy

To establish a versatile means for screening and management of nonalcoholic steatohepatitis (NASH), shear wave velocity was measured in 20 normal controls and 138 consecutive nonalcoholic fatty liver disease (NAFLD) cases. Referencing biochemical properties in 679 healthy volunteers, a formula to distinguish NASH suspects was established and validated in another cohort of 138 histologically proven NAFLD cases. NASH and simple steatosis (SS) suspects were selected based on a plot of shear wave velocity against age. A formula consisting of five factors (γ-glutamyl transpeptidase, alkaline phosphatase, platelet counts, body mass index, and presence/absence of type 2 diabetes mellitus) distinguished NASH suspects from SS suspects with area under the receiver operating characteristic curve values of 86% and 84% in the development and validation cohorts. Among 25 NAFLD cases in which shear wave velocity was repeatedly measured, 8 and 9 cases revealed an increase or decrease, respectively, of shear wave velocity in the entire liver, and the corresponding change in shear wave velocity was primarily observed in the right lobe or the left lateral segment, respectively. These results suggest that the new formula and sequential shear wave velocity measurements at each segment enable high throughput screening of NASH suspects and noninvasive assessment of pathophysiological alleviation/aggravation in cases of NASH.