Rodent nutritional model of steatohepatitis: effects of endotoxin (lipopolysaccharide) and tumor necrosis factor alpha deficiency

Metabolic Derangement in Non-Alcoholic Fatty Liver Disease: Opportunities for Early Diagnostic and Prognostic Markers

Non-alcoholic fatty liver disease is a globally prevalent disorder that can rapidly progress if not detected early. Currently, no accepted markers exist for early diagnosis and prognosis of NAFLD. This review describes derangement in major metabolic pathways of lipid, carbohydrate, and amino acids in NAFLD. It suggests that measuring levels of thrombospondin, TyG index, asymmetric dimethylarginine, LAL-A, GLP-1, FGF-21, and GSG index are potential markers for early diagnosis of NAFLD. A single marker may not indicate early NAFLD, and further large-scale studies on correlating levels of Thrombospondin-2, triglyceride-glucose index, and FGF-21 with NAFLD are warranted.

Single and Mixed Strains of Probiotics Reduced Hepatic Fat Accumulation and Inflammation and Altered Gut Microbiome in a Nonalcoholic Steatohepatitis Rat Model

As gut dysbiosis has been implicated in the pathogenesis of nonalcoholic steatohepatitis (NASH), probiotic supplementation might be a potential treatment for this condition. The aim of this study was to evaluate the effects of single- and mixed-strain probiotics on the severity of NASH induced by a high-fat, high-fructose (HFHF) diet and their mechanisms of action. Male Sprague-Dawley rats were divided into four groups (n = 7 per group): control group, NASH group, NASH + single-strain group, and NASH + mixed-strain group. In the single-strain and mixed-strain groups, rats received Lactobacillus plantarum B7 and Lactobacillus rhamnosus L34 + Lactobacillus paracasei B13 by oral gavage once daily, respectively. The duration of the study was 6 weeks. Liver tissue was used for histopathology, hepatic fat content was assessed by Oil Red O staining and hepatic free fatty acid (FFA), and hepatic TLR4 and CD14 expression were assessed by immunohistochemistry. Fresh feces was collected for gut microbiota analysis. Liver histology revealed a higher degree of fat accumulation, hepatocyte ballooning, and lobular inflammation in the NASH group, which improved in probiotics-treated groups. The amounts of hepatic fat droplets and hepatic FFA levels were more pronounced in the NASH group than in the control and treatment groups. Serum TNF- α levels were significantly higher in the NASH group than in control and probiotic groups. The expression of CD14 and TLR4 increased in the NASH group as compared with the control and probiotics-treated groups. Alpha diversity was reduced in the NASH group, but increased in both treatment groups. The relative abundance of Lactobacillus significantly decreased in the NASH group, but increased in both treatment groups. The relative abundance of Akkermansia significantly increased in the NASH group, but decreased in both treatment groups. In conclusion, both single-strain and mixed-strain probiotics could improve NASH histology by suppressing inflammatory responses in the liver, with this improvement potentially being associated with changes in the gut microbiota.

Effects of Probiotic Supplementation during Pregnancy on the Future Maternal Risk of Metabolic Syndrome

Probiotics are live microorganisms that induce health benefits in the host. Taking probiotics is generally safe and well tolerated by pregnant women and their children. Consumption of probiotics can result in both prophylactic and therapeutic effects. In healthy adult humans, the gut microbiome is stable at the level of the dominant taxa: Bacteroidetes, Firmicutes and Actinobacteria, and has a higher presence of Verrucomicrobia. During pregnancy, an increase in the number of Proteobacteria and Actinobacteria phyla and a decrease in the beneficial species Roseburia intestinalis and Faecalibacterium prausnitzii are observed. Pregnancy is a "window" to the mother's future health. The aim of this paper is to review studies assessing the potentially beneficial effects of probiotics in preventing the development of diseases that appear during pregnancy, which are currently considered as risk factors for the development of metabolic syndrome, and consequently, reducing the risk of developing maternal metabolic syndrome in the future. The use of probiotics in gestational diabetes mellitus, preeclampsia and excessive gestational weight gain is reviewed. Probiotics are a relatively new intervention that can prevent the development of these disorders during pregnancy, and thus, would reduce the risk of metabolic syndrome resulting from these disorders in the mother's future.

Intestinal Barrier and Permeability in Health, Obesity and NAFLD

The largest surface of the human body exposed to the external environment is the gut. At this level, the intestinal barrier includes luminal microbes, the mucin layer, gastrointestinal motility and secretion, enterocytes, immune cells, gut vascular barrier, and liver barrier. A healthy intestinal barrier is characterized by the selective permeability of nutrients, metabolites, water, and bacterial products, and processes are governed by cellular, neural, immune, and hormonal factors. Disrupted gut permeability (leaky gut syndrome) can represent a predisposing or aggravating condition in obesity and the metabolically associated liver steatosis (nonalcoholic fatty liver disease, NAFLD). In what follows, we describe the morphological-functional features of the intestinal barrier, the role of major modifiers of the intestinal barrier, and discuss the recent evidence pointing to the key role of intestinal permeability in obesity/NAFLD.

Liver Steatosis, Gut-Liver Axis, Microbiome and Environmental Factors. A Never-Ending Bidirectional Cross-Talk

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and parallels comorbidities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. Recent studies describe the presence of NAFLD in non-obese individuals, with mechanisms partially independent from excessive caloric intake. Increasing evidences, in particular, point towards a close interaction between dietary and environmental factors (including food contaminants), gut, blood flow, and liver metabolism, with pathways involving intestinal permeability, the composition of gut microbiota, bacterial products, immunity, local, and systemic inflammation. These factors play a critical role in the maintenance of intestinal, liver, and metabolic homeostasis. An anomalous or imbalanced gut microbial composition may favor an increased intestinal permeability, predisposing to portal translocation of microorganisms, microbial products, and cell wall components. These components form microbial-associated molecular patterns (MAMPs) or pathogen-associated molecular patterns (PAMPs), with potentials to interact in the intestine lamina propria enriched in immune cells, and in the liver at the level of the immune cells, i.e., Kupffer cells and stellate cells. The resulting inflammatory environment ultimately leads to liver fibrosis with potentials to progression towards necrotic and fibrotic changes, cirrhosis. and hepatocellular carcinoma. By contrast, measures able to modulate the composition of gut microbiota and to preserve gut vascular barrier might prevent or reverse NAFLD.

Gut Microbiota and Liver Interaction through Immune System Cross-Talk: A Comprehensive Review at the Time of the SARS-CoV-2 Pandemic

BACKGROUND AND AIMS

The gut microbiota is a complex ecosystem containing bacteria, viruses, fungi, yeasts and other single-celled organisms. It is involved in the development and maintenance of both innate and systemic immunity of the body. Emerging evidence has shown its role in liver diseases through the immune system cross-talk. We review herein literature data regarding the triangular interaction between gut microbiota, immune system and liver in health and disease.

METHODS

We conducted a search on the main medical databases for original articles, reviews, meta-analyses, randomized clinical trials and case series using the following keywords and acronyms and their associations: gut microbiota, microbiome, gut virome, immunity, gastrointestinal-associated lymphoid tissue (GALT), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steato-hepatitis (NASH), alcoholic liver disease, liver cirrhosis, hepatocellular carcinoma.

RESULTS

The gut microbiota consists of microorganisms that educate our systemic immunity through GALT and non-GALT interactions. The latter maintain health but are also involved in the pathophysiology and in the outcome of several liver diseases, particularly those with metabolic, toxic or immune-mediated etiology. In this context, gut virome has an emerging role in liver diseases and needs to be further investigated, especially due to the link reported between severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection and hepatic dysfunctions.

CONCLUSIONS

Changes in gut microbiota composition and alterations in the immune system response are involved in the pathogenesis of metabolic and immune-mediated liver diseases.

Combination of Probiotics and Salvia miltiorrhiza Polysaccharide Alleviates Hepatic Steatosis via Gut Microbiota Modulation and Insulin Resistance Improvement in High Fat-Induced NAFLD Mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) increases the risk of hepatocellular carcinoma, which is currently the leading cause of obesity-related cancer deaths in middle-aged men.

METHODS

Probiotics with lipid-lowering function were screened from the fecal microbiota of healthy adults. Polysaccharide from different sources was screened for improving insulin resistance. The combination of probiotics and Salvia miltiorrhiza polysaccharide (LBM) was investigated for alleviating hepatic steatosis.

RESULTS

First, Bifidobacterium bifidum V (BbV) and Lactobacillus plantarum X (LpX) were obtained from the fecal microbiota of healthy adults. Second, to improve insulin resistance, a Salvia miltiorrhiza Bunge polysaccharide showing good performance in reducing insulin resistance was obtained. The liver total cholesterol (TC) and total triglyceride (TG) levels and the serum levels of free fatty acid, alanine transaminase, aspartate transaminase, low density lipoprotein cholesterol, TG, and TC can be significantly reduced through supplementation with LpX-BbV (LB) in NAFLD mice. Interestingly, the function of the probiotic LB can be enhanced by S. miltiorrhiza Bunge polysaccharide. Furthermore, the gut microbiota was modulated by LpX-BbV+S. miltiorrhiza Bunge polysaccharide (LBM). The lipopolysaccharide concentration of the LBM group was decreased by 73.6% compared to the NAFLD group. Ultimately, the mRNA concentrations of the proinflammatory cytokines (tumor necrosis factor α, interleukin 1β [IL-1β], and IL-6) decreased with LB and LBM treatment.

CONCLUSION

The results of this this study indicate that the LBM combination can be used as a therapeutic for ameliorating NAFLD via modulating the gut microbiota and improving insulin resistance.

Liver disease symptoms in non-alcoholic fatty liver disease and small intestinal bacterial overgrowth

INTRODUCTION

It seems that there is a relationship between small intestinal bacterial overgrowth (SIBO) and non-alcoholic fatty liver disease (NAFLD). The main objective of this study was to evaluate the prevalence of SIBO among NAFLD patients.

METHODS

In this descriptive-analytical cross-sectional study, 98 eligible NAFLD patients were evaluated for SIBO using hydrogen breath test (HBT). They were divided into SIBO-positive and SIBO-negative groups. Demographic, clinical, and laboratory data were obtained.

RESULTS

Based on the HBT, 38 patients (39%) had bacteria overgrowth. There were no significant differences between SIBO-positive and SIBO-negative regarding demographic data and BMI classification (P > 0.05). Biochemical variables, the results of abdominal ultrasound, and liver elastography did not show any significant difference between SIBO-positive and SIBO-negative patients (P > 0.05). Patients with SIBO were found to have higher rates of bloating, while abdominal pain was more prevalent in SIBO-negative patients (P < 0.001).

CONCLUSIONS

SIBO is prevalent in NAFLD and associated with bloating in these patients. Further studies are necessary to elucidate if therapeutic manipulation of gut microbiota reduces the risk of NAFLD, fibrosis, and liver cirrhosis.

Intestinal Barrier Function-Non-alcoholic Fatty Liver Disease Interactions and Possible Role of Gut Microbiota

Non-alcoholic fatty liver disease (NAFLD) is a metabolic stress liver injury that is closely related to obesity, insulin resistance, type 2 diabetes, atherosclerosis, and metabolic syndrome. The pathological features are diffuse hepatic vesicular steatosis, including non-alcoholic steatohepatitis, liver fibrosis, and even liver cancer. A variety of pathological outcomes cause serious harm to human health. At present, an increasing number of researchers are investigating the pathogenesis of NAFLD from the perspective of changes in the function of the intestinal barrier. The physical, chemical, immunological, and microbiological barriers in the intestinal tract constitute the complete intestinal barrier, which plays an important defensive role against the invasion of harmful substances from the intestines. Protecting the function of the intestinal barrier is a new way to treat NAFLD and its related diseases. In this perspective, we summarized the current knowledge of the role of the intestinal barrier in NAFLD.

Intestinally derived bacterial products stimulate development of nonalcoholic steatohepatitis

Fatty livers are susceptible to factors that cause inflammation and fibrosis, but fat deposition and the inflammatory response can be dissociated. While nonalcoholic fatty liver disease (NAFLD), caused by pathologic fat accumulation inside the liver, can remain stable for several years, in other cases NAFLD progresses to nonalcoholic steatohepatitis (NASH), which is characterized by fat accumulation and inflammation and is not a benign condition. In this review, we discuss the NASH host cells and microbial mechanisms that stimulate inflammation and predispose the liver to hepatocyte injury and fibrotic stages via increased lipid deposition. We highlight the interactions between intestine-derived bacterial products, such as lipopolysaccharide, and nutritional models of NAFLD and/or obese individuals. The results of modulating enteric microbiota suggest that gut-derived endotoxins may be essential determinants of fibrotic progression and regression in NASH.

Influence of gut microbiota on the development and progression of nonalcoholic steatohepatitis

INTRODUCTION

Nonalcoholic steatohepatitis (NASH) is characterized by the presence of steatosis, inflammation, and ballooning degeneration of hepatocytes, with or without fibrosis. The prevalence of NASH has increased with the obesity epidemic, but its etiology is multifactorial. The current studies suggest the role of gut microbiota in the development and progression of NASH. The aim is to review the studies that investigate the relationship between gut microbiota and NASH. These review also discusses the pathophysiological mechanisms and the influence of diet on the gut-liver axis.

RESULT

The available literature has proposed mechanisms for an association between gut microbiota and NASH, such as: modification energy homeostasis, lipopolysaccharides (LPS)-endotoxemia, increased endogenous production of ethanol, and alteration in the metabolism of bile acid and choline. There is evidence to suggest that NASH patients have a higher prevalence of bacterial overgrowth in the small intestine and changes in the composition of the gut microbiota. However, there is still a controversy regarding the microbiome profile in this population. The abundance of Bacteroidetes phylum may be increased, decreased, or unaltered in NASH patients. There is an increase in the Escherichia and Bacteroides genus. There is depletion of certain taxa, such as Prevotella and Faecalibacterium.

CONCLUSION

Although few studies have evaluated the composition of the gut microbiota in patients with NASH, it is observed that these individuals have a distinct gut microbiota, compared to the control groups, which explains, at least in part, the genesis and progression of the disease through multiple mechanisms. Modulation of the gut microbiota through diet control offers new challenges for future studies.

Serum Pentraxin 3 Fragment as a Noninvasive Marker of Nonalcoholic Fatty Liver Disease in Obese Children and Adolescents

BACKGROUND/AIMS

It was suggested that serum pentraxin 3 (PTX3) levels could differentiate obese children with nonalcoholic steatohepatitis (NASH) from those with simple steatosis. Thus, we aimed to evaluate the clinical utility of serum PTX3 fragment levels in the diagnosis of NASH and the assessment of its severity in obese children with suspected nonalcoholic fatty liver disease (NAFLD).

METHODS

Fifty obese children were compared to 25 matched controls. All were subjected to history taking, anthropometric measurements, and abdominal ultrasonography, as well as laboratory assessments of liver functions, fasting lipid profile, fasting blood glucose, fasting insulin, homeostasis model assessment (HOMA) index, fasting glucose/insulin ratio, and serum PTX3.

RESULTS

PTX3 was higher in obese cases than controls (p = 0.0001). Eighty percent of the cases had NAFLD with progressive increases in PTX3 levels as the severity of fatty liver increased (p = 0.0001). Moreover, PTX3 was higher in cases with elevated liver enzymes (3.205 ± 0.77 U/l) than those with normal liver enzymes (2.77 + 0.69 U/l, p < 0.0001). A cutoff value of 3.03 U/l differentiated fatty liver from NASH with a sensitivity of 89% and a specificity of 86%.

CONCLUSION

Noninvasive monitoring of serum PTX3 fragment levels in obese patients with suspected NAFLD may be used as a reliable tool for differentiating NASH from simple fatty liver.

Fecal microbiota transplantation for gastrointestinal disorders

PURPOSE OF REVIEW

The importance of the gut microbiome in human health is being increasingly recognized. The purpose of this review is to examine the existing literature pertaining to alterations in the gut microbiome and the utility of microbiome restoration therapies in gastrointestinal disorders.

RECENT FINDINGS

Imbalance and maladaptation of the microbiome, termed dysbiosis, has been associated with several disease states such as irritable bowel syndrome, Clostridium difficile infection, inflammatory bowel diseases, nonalcoholic fatty liver disease, and obesity among others. The possibility of restoration of normal microbiota has become an attractive concept for diseases in which the normal microbiome is perturbed. The rationale of using fecal microbiota transplantation to treat disease has been validated by its successful use in treating recurrent Clostridium difficile infection, which occurs as a result of decreased microbial diversity in the gut, most often in the setting of recent antibiotic treatment. Similar strategies may be applicable to other disorders.

SUMMARY

Alterations in the gut microbiome are associated with several disorders, and microbiome restoration based therapies such as fecal microbiota transplantation may be an adjunct to conventional treatments but more investigation is needed.

Obesity and colorectal liver metastases: Mechanisms and management

INTRODUCTION

Colorectal cancer (CRC) is the third commonest malignancy after lung and breast cancer. The most common cause of mortality from CRC is from distant metastases. Obesity is a known risk factor for primary CRC development. However, its role in metastatic disease progression is not fully understood. The article aims to provide an overview of the role of obesity in colorectal liver metastases (CRLM). Furthermore, possible strategies to minimise this effect are discussed. An electronic search of MedLine, EMBASE, CINAHL and google scholar was performed. Relevant articles were included in the article. Obesity causes localised inflammation within the liver microenvironment which may predispose to metastases development. Furthermore, obesity causes systemic inflammation leading to release of protumourigenic growth factors. Several studies demonstrated the effects of lifestyle modification, medications, bariatric surgery and omega-3 fatty acids on steatosis within the context of liver surgery. It is currently unclear whether obesity directly leads to metastatic disease via chronic systemic inflammation or whether obesity induced steatosis provides a fertile microenvironment for metastases deposition. With a global increase in obesity useful strategies to minimise the effects of obesity on the liver include life-style modification, pre-operative dietary regimes and omega-3 fatty acids intake. Pre-operative optimisation of the patient is a key concept. Further randomised control trials are needed to guide management strategies.

Gut Microbiota and Lifestyle Interventions in NAFLD

The human digestive system harbors a diverse and complex community of microorganisms that work in a symbiotic fashion with the host, contributing to metabolism, immune response and intestinal architecture. However, disruption of a stable and diverse community, termed "dysbiosis", has been shown to have a profound impact upon health and disease. Emerging data demonstrate dysbiosis of the gut microbiota to be linked with non-alcoholic fatty liver disease (NAFLD). Although the exact mechanism(s) remain unknown, inflammation, damage to the intestinal membrane, and translocation of bacteria have all been suggested. Lifestyle intervention is undoubtedly effective at improving NAFLD, however, not all patients respond to these in the same manner. Furthermore, studies investigating the effects of lifestyle interventions on the gut microbiota in NAFLD patients are lacking. A deeper understanding of how different aspects of lifestyle (diet/nutrition/exercise) affect the host-microbiome interaction may allow for a more tailored approach to lifestyle intervention. With gut microbiota representing a key element of personalized medicine and nutrition, we review the effects of lifestyle interventions (diet and physical activity/exercise) on gut microbiota and how this impacts upon NAFLD prognosis.

Microbiota, immunity and the liver

The gut harbors a complex community of over 100 trillion microbial cells known to exist in symbiotic harmony with the host influencing human physiology, metabolism, nutrition and immune function. It is now widely accepted that perturbations of this close partnership results in the pathogenesis of several major diseases with increasing evidence highlighting their role outside of the intestinal tract. The intimate proximity and circulatory loop of the liver and the gut has attracted significant attention regarding the role of the microbiota in the development and progression of liver disease. Here we give an overview of the interaction between the microbiota and the immune system and focus on their convincing role in both the propagation and treatment of liver disease.

Intestinal microbiota in liver disease

The intestinal microbiota have emerged as a topic of intense interest in gastroenterology and hepatology. The liver is on the front line as the first filter of nutrients, toxins and bacterial metabolites from the intestines and we are becoming increasingly aware of interactions among the gut, liver and immune system as important mediators of liver health and disease. Manipulating the microbiota with therapeutic intent is a rapidly expanding field. In this review, we will describe what is known about the contribution of intestinal microbiota to liver homeostasis; the role of dysbiosis in the pathogenesis of liver disease including alcoholic and non-alcoholic fatty liver disease, cirrhosis and hepatocellular carcinoma; and the therapeutic manifestations of altering intestinal microbiota via antibiotics, prebiotics, probiotics and fecal microbiota transplantation.

Gut Microbiota: Association with NAFLD and Metabolic Disturbances

Nonalcoholic fatty liver disease is the hepatic expression of metabolic syndrome, being frequently associated with obesity, insulin resistance, and dyslipidemia. Recent lines of evidence have demonstrated a role of gut microbiota in insulin resistance, obesity, and associated metabolic disturbances, raising the interest in its relationship with NAFLD pathogenesis. Therefore, intestinal microbiota has emerged as a potential factor involved in NAFLD, through different pathways, including its influence in energy storage, lipid and choline metabolism, ethanol production, immune balance, and inflammation. The main objective of this review is to address the pathogenic association of gut microbiota to NAFLD. This comprehension may allow the development of integrated strategies to modulate intestinal microbiota in order to treat NAFLD.

Paradoxical impact of the remnant pancreatic volume and infectious complications on the development of nonalcoholic fatty liver disease after pancreaticoduodenectomy

BACKGROUND

The aim of the present study was to evaluate perioperative risk factors for development of nonalcoholic fatty liver disease (NAFLD) after pancreaticoduodenectomy (PD), paying special attention to remnant pancreatic volume (RPV) and postoperative infection.

METHODS

We reviewed the charts of 110 patients who had been followed more than 6 months after PD. These patients were classified into the two groups according to RPV measured by CT volumetry at one month: large-volume group (LVG) (10 ml or more, n = 75) and small-volume group (SVG) (less than 10 ml, n = 35).

RESULTS

Nonalcoholic fatty liver disease developed in 44 (40.0%), being significantly higher in SVG than in LVG: 54.2% vs. 33.3% (P = 0.037). SVG was characterized as significantly higher incidence of pancreatic adenocarcinoma, while LVG was characterized as significantly higher incidences of soft pancreas, postoperative infection and pancreatic fistula. In LVG, the incidence of NAFLD was significantly higher in patients with suspicion of infection than in those without it: 45.2% vs. 18.1% (P = 0.014), while not different in SVG. By multivariate analysis, independent risk factor was determined as RPV and suspicion of infection in the whole patients, and in LVG it was suspicion of infection, while in SVG it was not identified.

CONCLUSION

After PD, RPV and status of postoperative infection paradoxically influenced the development of NAFLD.

Non-alcoholic fatty liver disease, diet and gut microbiota

Non-alcoholic fatty liver disease (NAFLD) is a severe liver disease that is increasing in prevalence with the worldwide epidemic of obesity and its related insulin-resistance state. Evidence for the role of the gut microbiota in energy storage and the subsequent development of obesity and some of its related diseases is now well established. More recently, a new role of gut microbiota has emerged in NAFLD. The gut microbiota is involved in gut permeability, low-grade inflammation and immune balance, it modulates dietary choline metabolism, regulates bile acid metabolism and produces endogenous ethanol. All of these factors are molecular mechanisms by which the microbiota can induce NAFLD or its progression toward overt non-alcoholic steatohepatitis. Modification of the gut microbiota composition and/or its biochemical capacity by specific dietary or pharmacological interventions may advantageously affect host metabolism. Large-scale intervention trials, investigating the potential benefit of prebiotics and probiotics in improving cardiometabolic health in high-risk populations, are fervently awaited.

Gut-liver axis and fibrosis in nonalcoholic fatty liver disease: an input for novel therapies

Non-alcoholic fatty liver disease is a multifactorial condition, ranging from simple steatosis to non-alcoholic steatohepatitis with or without fibrosis. In non-alcoholic fatty liver disease, alteration of gut microbiota and increased intestinal permeability increase exposure of the liver to gut-derived bacterial products: lipopolysaccharides and unmethylated CpG DNA. These products stimulate innate immune receptors, namely Toll-like receptors, which activate signalling pathways involved in liver inflammation and fibrogenesis. Currently, there are several studies on the involvement of lipopolysaccharide-activated Toll-like receptor 4 signalling in non-alcoholic fatty liver disease pathogenesis. There has been widespread interest in the study of the involvement of resident hepatic stellate cells and Kupffer cells activation in liver fibrogenesis upon TLR4 stimulation. Although the best evidence to support a role for gut microbiota in non-alcoholic fatty liver disease-induced fibrosis comes largely from animal models, data from human studies are accumulating and could lead to new therapeutic approaches. Therapeutic modulation of gut microflora may be an alternative strategy to develop an anti-fibrotic therapy. In this review, we discuss the relevant role of gut-liver axis in non-alcoholic liver disease-associated liver fibrosis and discuss the evidence on novel anti-fibrotic therapeutic approaches.

The pro-inflammatory action of tumour necrosis factor-α in non-alcoholic steatohepatitis is independent of the NSMAF gene product

BACKGROUND

The role of tumour necrosis factor-α (TNF-α) in the development of non-alcoholic steatohepatitis remains unclear.

AIMS

We evaluated the role of TNF-α and NSMAF gene product factor associated with neutral sphingomyelinase activation, a protein adaptor of the TNF-α receptor-1, in a mouse model of non-alcoholic steatohepatitis.

METHODS

Mice deficient either for TNF-α or factor associated with neutral sphingomyelinase activation, as well as control animals, were fed a methionine and choline-deficient diet for 5 weeks. Liver histology, serum glucose, triglycerides, cholesterol and alanine aminotransferase levels were compared between groups.

RESULTS

Weight loss, decrease of serum triglyceride and glucose levels and increase of alanine aminotransferase levels were attenuated in TNF(-/-) mice. Similarly, we found a significantly lower lobular inflammation in TNF(-/-) mice. Liver expression of transforming growth factor-β, peroxisome proliferator-activated receptor-γ(1, 2) and monocyte chemoattractant protein-1 was attenuated in TNF(-/-) mice. In addition, the phosphatidylcholine/phosphatidylethanolamine liver ratio decrease was less important in TNF(-/-) mice. The increase in hepatic sphingomyelin and ceramide levels was less pronounced in TNF(-/-) animals.

CONCLUSION

Whereas TNF-α modulates the inflammatory process that underlies methionine and choline-deficient diet-induced non-alcoholic steatohepatitis, its effects are not mediated by factor associated with neutral sphingomyelinase activation. Whether changes in liver lipids, like phosphatidylcholine and ceramide, are causally involved in tumour necrosis factor-mediated liver inflammation remains an open issue.

DSS induced colitis increases portal LPS levels and enhances hepatic inflammation and fibrogenesis in experimental NASH

BACKGROUND & AIMS

Intestinal bacterial overgrowth and increased permeability are features of non alcoholic steatohepatitis (NASH). Bacterial endotoxin has been shown to promote NASH progression. Application of dextran sulfate sodium (DSS) is a colitis model in mice characterized by damage of the intestinal barrier. This study was designed to investigate if application of DSS aggravates experimental NASH.

METHODS

Male C57bl/6 mice were allocated into four experimental groups receiving either (I) standard chow (SC), (II) a high fat (HF) diet, (III) SC+DSS (1% in the drinking water), and (IV) HF+DSS for 12 weeks.

RESULTS

DSS treatment caused inflammation and proinflammatory gene expression (IL-1β, IL-17, TNF) in the colon. Expression of colonic antimicrobial peptide Cramp was significantly induced in SC+DSS mice, whereas expression was blocked in the HF+DSS group. Endotoxin levels were elevated in SC+DSS and HF mice but further augmented in the HF+DSS group. In line with this, increased hepatic TLR4 and TLR9 mRNA levels were detected in HF+DSS mice. The histological analysis revealed hepatic steatosis in both HF groups. Hepatic inflammation was more severe in HF+DSS mice, reflected by histology and analysis of proinflammatory gene expression (TNF and MCP-1). HF+DSS mice showed increased hepatic fibrosis by sirius red staining, hepatic collagen I expression, and α-SMA positive cells accompanied by higher p47(phox), TIMP-1, TGF-β, Pai-1, and α-SMA mRNA expression.

CONCLUSIONS

Induction of an intestinal inflammation in experimental NASH promotes LPS translocation, hepatic inflammation, and fibrogenesis probably due to inhibition of intestinal antimicrobial peptides. These findings underscore the pathophysiological role of the gut-liver axis in the progression of NASH.

[Nonalcoholic fatty liver disease]

NAFLD encompasses a spectrum of liver diseases including simple steatosis and nonalcoholic steatohepatitis (NASH), which is characterized by inflammation and hepatocyte ballooning on a background of steatosis. NAFLD, the hepatic manifestation of the metabolic syndrome, has become one of the most common causes of chronic liver diseases over the last decade in developed countries as well as in low and middle-income regions owing to dramatic epidemic proportions of obesity and diabetes worldwide. While simple steatosis has mostly a benign course, NASH can lead to fibrosis, cirrhosis and hepatocellular carcinoma. Insulin resistance is considered as the cornerstone in the development of NAFLD/NASH. Liver biopsy remains the gold standard for the diagnosis of NASH. However, non-invasive markers of NASH and fibrosis represent interesting tools to identify patients with severe liver injuries. Even if insulin sensitizers and hepatoprotective agents are promising drugs, no medication has been currently approved for the treatment of NASH. Diet, exercise and control of the metabolic disorders still represent crucial therapeutic options for the management of NAFLD/NASH.

The role of the gut microbiota in nonalcoholic fatty liver disease

Important metabolic functions have been identified for the gut microbiota in health and disease. Several lines of evidence suggest a role for the gut microbiota in both the etiology of nonalcoholic fatty liver disease (NAFLD) and progression to its more advanced state, nonalcoholic steatohepatitis (NASH). Both NAFLD and NASH are strongly linked to obesity, type 2 diabetes mellitus and the metabolic syndrome and, accordingly, have become common worldwide problems. Small intestinal bacterial overgrowth of Gram-negative organisms could promote insulin resistance, increase endogenous ethanol production and induce choline deficiency, all factors implicated in NAFLD. Among the potential mediators of this association, lipopolysaccharide (a component of Gram-negative bacterial cell walls) exerts relevant metabolic and proinflammatory effects. Although the best evidence to support a role for the gut microbiota in NAFLD and NASH comes largely from animal models, data from studies in humans (albeit at times contradictory) is accumulating and could lead to new therapeutic avenues for these highly prevalent conditions.

The effect of rat strain, diet composition and feeding period on the development of a nutritional model of non-alcoholic fatty liver disease in rats

Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver-related morbidity and mortality. The aim of this work was to establish and characterize a nutritional model of NAFLD in rats. Wistar or Sprague-Dawley male rats were fed ad libitum a standard diet (ST-1, 10 % kcal fat), a medium-fat gelled diet (MFGD, 35 % kcal fat) and a high-fat gelled diet (HFGD, 71 % kcal fat) for 3 or 6 weeks. We examined the serum biochemistry, the hepatic malondialdehyde, reduced glutathione (GSH) and cytokine concentration, the respiration of liver mitochondria, the expression of uncoupling protein-2 (UCP-2) mRNA in the liver and histopathological samples. Feeding with MFGD and HFGD in Wistar rats or HFGD in Sprague-Dawley rats induced small-droplet or mixed steatosis without focal inflammation or necrosis. Compared to the standard diet, there were no significant differences in serum biochemical parameters, except lower concentrations of triacylglycerols in HFGD and MFGD groups. Liver GSH was decreased in rats fed HFGD for 3 weeks in comparison with ST-1. Higher hepatic malondialdehyde was found in both strains of rats fed HFGD for 6 weeks and in Sprague-Dawley groups using MFGD or HFGD for 3 weeks vs. the standard diet. Expression of UCP-2 mRNA was increased in Wistar rats fed MFGD and HFGD for 6 weeks and in Sprague-Dawley rats using HFGD for 6 weeks compared to ST-1. The present study showed that male Wistar and Sprague-Dawley rats fed by HFGD developed comparable simple steatosis without signs of progression to non-alcoholic steatohepatitis under our experimental conditions.

Nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in the Western world, is a clinico-histopathological entity in which excessive triglyceride accumulation in the liver occurs. Non-alcoholic steatohepatitis (NASH) represents the necroinflammatory form, which can lead to advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. The pathogenesis of NAFLD/NASH is complex but increased visceral adiposity plus insulin resistance with increased free fatty acids release play an initial key role for the onset and perpetuation of liver steatosis. Further events in the liver include oxidative stress and lipid peroxidation, decreased antioxidant defences, early mitochondrial dysfunction, iron accumulation, unbalance of adipose-derived adipokines with a chronic proinflammatory status, and gut-derived microbial adducts. New gene polymorphisms increasing the risk of fatty liver, namely APOC3 and PNPLA3, have been lately identified allowing further insights into the pathogenesis of this condition. In our review pathophysiological, genetic, and essential diagnostic and therapeutic aspects of NAFLD are examined with future trends in this field highlighted.

Endotoxin and plasminogen activator inhibitor-1 serum levels associated with nonalcoholic steatohepatitis in children

OBJECTIVES

Recent evidence supports a role for endotoxemia in the progression from nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis (NASH). We investigated the association between serum levels of endotoxin, proinflammatory molecules, and histology in children with NAFLD.

PATIENTS AND METHODS

A total of 40 children, mean age of 11.9 +/- 2.8 years (27 male and 13 female), with biopsy-proven NAFLD were consecutively enrolled. Anthropometrics, blood pressure, and parameters of the metabolic syndrome were collected. Serum levels of endotoxin, plasminogen activator inhibitor-1 (PAI-1), tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 were measured by an enzyme-linked immunosorbent assay and compared with circulating levels of the same soluble factors in 9 age- and sex-matched normal weight controls (age 11.4 +/- 1.7 years; 6 boys and 3 girls).

RESULTS

Children with NAFLD had markedly higher serum concentrations of endotoxin (P < 0.01), PAI-1 (P < 0.001), TNF-alpha, and IL-6 (P < 0.05) than control subjects. Endotoxin (P = 0.002), PAI-1, (P < 0.001), IL-6 (P = 0.002), TNF-alpha (P = 0.02), and body mass index (P = 0.03) were significantly associated with a NAFLD activity score >or=5 at the univariate analysis. At the stepwise regression analysis, endotoxin (P < 0.0001) and PAI-1 (P = 0.009) were the most significant predictors for NAFLD activity score.

CONCLUSIONS

Our findings demonstrate that, apart from TNF-alpha and IL-6, endotoxin and PAI-1 may represent good markers of NASH. They also reinforce the hypothesis that elevated levels of endotoxin may contribute to the progression from NAFLD to NASH.

The traditional Japanese formula keishibukuryogan reduces liver injury and inflammation in patients with nonalcoholic fatty liver disease

The Kampo formula keishibukuryogan (KBG, Guizhifulingwan) is frequently used in traditional Japanese and Chinese medicine to treat several symptoms and manifests anti-inflammatory and scavenging effects. Nonalcoholic fatty liver disease (NAFLD) is a common manifestation of the metabolic syndrome and has the potential to evolve to liver cirrhosis through chronic inflammation and steatohepatisis (NASH). We have recently reported the KBG significant effectiveness on liver injury in a NASH animal model that prompted us to prescribe to KBG (TJ-25). We performed a retrospective study and reviewed the charts of outpatients who were prescribed KBG for 8-12 weeks due to non-liver-related symptoms (n= 11) over the past year to evaluate the clinical outcome. In six of these cases, biochemical and ultrasound signs of NAFLD were observed. KBG led to a significant reduction in liver injury tests and blood cholesterol but had no effects on body weight in all NAFLD cases. Further, liver tests and lipid profiles returned to baseline values when KBG treatment was stopped. On the basis of data on a small number of subjects, we suggest that the use of KBG is a safe complementary treatment in patients with NAFLD. While it is unlikely that Kampo formulas may substitute the current nutritional approaches to the metabolic syndrome, future studies should address the possibility of an additive effect, possibly through anti-inflammatory mechanisms.

Cyclic AMP-guanine exchange factor activation inhibits JNK-dependent lipopolysaccharide-induced apoptosis in rat hepatocytes

Lipopolysaccharide (LPS) is known to damage hepatocytes by cytokines released from activated Kupffer cells, but the ancillary role of LPS as a direct hepatotoxin is less well characterized. The aim of this study was to determine the direct effect of LPS on hepatocyte viability and the underlying signaling mechanism. Rat hepatocyte cultures treated overnight with LPS (500 ng/mL) induced apoptosis as monitored morphologically (Hoechst 33258) and biochemically (cleavage of caspase 3 and 9 and the appearance of cytochrome C in the cytoplasm). LPS-induced apoptosis was additive to that induced by glycochenodeoxycholate or Fas ligand, was associated with activation of c-Jun N-terminal kinase B (JNK) and p38 mitogen-activated protein kinases (MAPK), and inhibition of protein kinase (AKT). Inhibition of JNK by SP600125, but not of p38 MAPK by SB203580 attenuated LPS-induced apoptosis, indicating JNK dependency. CPT-2-Me-cAMP, an activator of cAMP-GEF, decreased apoptosis due to LPS alone or in combination with glycochenodeoxycholate or Fas ligand. CPT-2-Me-cAMP also prevented LPS-induced activation of JNK and inhibition of AKT. Taken together, these results suggest that LPS can induce hepatocyte apoptosis directly in vitro in a JNK-dependent manner and activation of cAMP-GEF protects against the LPS-induced apoptosis most likely by reversing the effect of LPS on JNK and AKT.

Nitrosamine exposure exacerbates high fat diet-mediated type 2 diabetes mellitus, non-alcoholic steatohepatitis, and neurodegeneration with cognitive impairment

Background

The current epidemics of type 2 diabetes mellitus (T2DM), non-alcoholic steatohepatitis (NASH), and Alzheimer's disease (AD) all represent insulin-resistance diseases. Previous studies linked insulin resistance diseases to high fat diets or exposure to streptozotocin, a nitrosamine-related compound that causes T2DM, NASH, and AD-type neurodegeneration. We hypothesize that low-level exposure to nitrosamines that are widely present in processed foods, amplifies the deleterious effects of high fat intake in promoting T2DM, NASH, and neurodegeneration.

Methods

Long Evans rat pups were treated with N-nitrosodiethylamine (NDEA) by i.p. Injection, and upon weaning, they were fed with high fat (60%; HFD) or low fat (5%; LFD) chow for 6 weeks. Rats were evaluated for cognitive impairment, insulin resistance, and neurodegeneration using behavioral, biochemical, molecular, and histological methods.

Results

NDEA and HFD ± NDEA caused T2DM, NASH, deficits in spatial learning, and neurodegeneration with hepatic and brain insulin and/or IGF resistance, and reductions in tau and choline acetyltransferase levels in the temporal lobe. In addition, pro-ceramide genes, which promote insulin resistance, were increased in livers and brains of rats exposed to NDEA, HFD, or both. In nearly all assays, the adverse effects of HFD+NDEA were worse than either treatment alone.

Conclusions

Environmental and food contaminant exposures to low, sub-mutagenic levels of nitrosamines, together with chronic HFD feeding, function synergistically to promote major insulin resistance diseases including T2DM, NASH, and AD-type neurodegeneration. Steps to minimize human exposure to nitrosamines and consumption of high-fat content foods are needed to quell these costly and devastating epidemics.

IL-6 deficiency attenuates murine diet-induced non-alcoholic steatohepatitis

BACKGROUND

The role of inflammation in the pathogenesis of non-alcoholic steatohepatitis (NASH), a common cause of liver disease, is still poorly understood. This study aimed at assessing the involvement of a major inflammatory cytokine, IL-6, in NASH.

MATERIALS AND METHODS

Steatohepatitis was induced by feeding wild-type or IL-6(-/-) mice for 5 weeks with a methionine and choline-deficient (MCD) diet.

RESULTS

Whereas MCD diet-induced weight loss and decreases in serum glucose, cholesterol and triglyceride levels were similar in both genotypes, serum alanine aminotransferase was less elevated in IL-6(-/-) mice than in wild-type animals. Despite having a comparable liver steatosis score, IL-6-deficient mice exhibited less lobular inflammation than their wild-type littermates. Liver gene expression of TGF-beta and MCP-1 was also strongly attenuated in mutant mice; a more modest reduction was observed for PPAR-gamma and F4/80 transcripts as well as proteins. Chromatographic analysis of liver lipids demonstrated that MCD diet induced in normal and mutant mice a similar decrease in the ratio of phosphatidylcholine to phosphatidylethanolamine. However, the diet-induced increase in the levels of sphingomyelin and ceramide was less important in IL-6(-/-) mice.

CONCLUSION

Altogether, these results indicate that IL-6 deficiency does not block the development of NASH; yet, IL-6 plays a critical role in the accompanying liver inflammation.

The liver and the waistline: Fifty years of growth

Fifty years of the Gastroenterological Society of Australia have witnessed the changing appearance of Australians. Asian immigration has transformed the dominant urban culture from European to Eurasian, with some unique Australian attributes. Meanwhile, global conditions have altered body shape, and our sports-proud country is now fat! Thus, as in North America, Europe, China, and affluent Asia-Pacific countries, prosperity and lifestyle, cheap processed foods coupled with reduced physical activity have created an epidemic of over-nutrition resulting in overweight/obesity. Additional genetic factors are at the core of the apple shape (central obesity) that typifies over-nourished persons with metabolic syndrome. Indigenous Australians, once the leanest and fittest humans, now have exceedingly high rates of obesity and type 2 diabetes, contributing to shorter life expectancy; Asian Australians are also at higher risk. Like non-steroidal anti-inflammatory drugs (NSAIDs) and cigarette smoking, obesity now contributes much to gastrointestinal morbidity and mortality (gastroesophageal reflux disease, cancers, gallstones, endoscopy complications). This review focuses on Australian research about fatty liver, particularly roles of central obesity/insulin resistance in non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH). The outputs include many highly cited original articles and reviews and the first book on NAFLD. Studies have identified community prevalence, clinical outcomes, association with insulin resistance, metabolic syndrome and hypoadiponectinemia, developed and explored animal models for mechanisms of inflammation and fibrosis, conceptualized etiopathogenesis, and demonstrated that NASH can be reversed by lowering body weight and increasing physical activity. The findings have led to development of regional guidelines on NAFLD, the first internationally, and should now inform daily practice of gastroenterologists.

Silencing of TLR4 decreases liver tumor burden in a murine model of colorectal metastasis and hepatic steatosis

BACKGROUND

The relationship between obesity and cancer has become of particular interest due to the rapidly growing prevalence of overweight individuals. Obesity predisposes individuals to the development of hepatic steatosis and is an independent risk factor for several neoplasms. Toll-like receptor 4 (TLR4) is the innate receptor for endotoxin, and steatotic livers are known to be sensitive to endotoxin. TLR4 signaling has been shown to have proneoplastic effects in vitro due to its effect on immune surveillance. Thus far, studies have predominantly focused on the effect of tumor-cell-derived TLR4 without regard to host TLR4 signaling.

RESULTS

In the present study we show that steatotic livers have increased expression of TLR4. Obese animals developed higher metastatic tumor burden in the liver than lean controls regardless of the presence or absence of intact host TLR4. After silencing TLR4 expression using RNAi in the mouse colon cancer cell line MC38, there was a significant decrease in metastatic tumor burden within the liver of obese animals.

CONCLUSIONS

These findings demonstrate that steatotic livers have increased susceptibility to metastatic tumor growth and that silencing tumor cell TLR4 reduces metastatic tumor burden in steatotic liver.

Hepatic ceramide may mediate brain insulin resistance and neurodegeneration in type 2 diabetes and non-alcoholic steatohepatitis

Obesity, type 2 diabetes mellitus (T2DM), and non-alcoholic steatohepatitis (NASH) can be complicated by cognitive impairment and neurodegeneration. Experimentally, high fat diet (HFD)-induced obesity with T2DM causes mild neurodegeneration with brain insulin resistance. Since ceramides are neurotoxic, cause insulin resistance, and are increased in T2DM, we investigated the potential role of ceramides as mediators of neurodegeneration in the HFD obesity/T2DM model. We pair-fed C57BL/6 mice with a HFD or control diet for 4-20 weeks and examined pro-ceramide gene expression in liver and brain and neurodegeneration in the temporal lobe. HFD feeding gradually increased body weight, but after 16 weeks, liver weight surged (P<0.001) due to lipid (triglyceride) accumulation (P<0.001), and brain weight declined (P<0.0001-Trend analysis). HFD feeding increased ceramide synthase, serine palmitoyl transferase, and sphingomyelinase expression in liver (P<0.05-P<0.001), but not brain. In HFD fed mice, temporal lobe levels of ubiquitin (P<0.001) and 4-hydroxynonenal (P<0.05 or P<0.01) increased, and tau, beta-actin, and choline acetyltransferase levels decreased (P<0.05-P<0.001) with development of NASH. In obesity, T2DM, or NASH, neurodegeneration with brain insulin resistance may be mediated by excess hepatic production of neurotoxic ceramides that readily cross the blood-brain barrier.

Plasma Pentraxin3 is a novel marker for nonalcoholic steatohepatitis (NASH)

Background

The changes in the liver in nonalcoholic fatty liver disease (NAFLD) range over a wide spectrum, extending from steatosis to steatohepatitis (NASH). However it has remained difficult to differentiate between NASH and non-progressive NAFLD on the basis of the clinical findings alone.

Aims

In this study we investigated the clinical usefulness of plasma Pentraxin3 (PTX3) levels to predict NASH. Plasma PTX3 was measured in 70 patients with histologically verified NAFLD (28 with non-NASH and 42 with NASH) and 10 healthy control subjects.

Results

The plasma PTX3 level was significantly higher in the NASH cases than in the non-NASH cases (p = 0.0021) and control subjects (p = 0.045). And the plasma PTX3 level was significantly higher in the stages 3–4 NAFLD cases than in the stages 0–2 NAFLD cases (p < 0.0001). The PTX3 values were closely correlated with the stages of liver fibrosis (p < 0.0001, Kruskal-Wallis test). To detect NASH compared with non-NASH, the area under the curve for plasma PTX3 were 0.755, and to detect stages 3–4 NAFLD compared with stages 0–2 NAFLD, the area under the curve for plasma PTX3 were 0.850.

Conclusion

This is the first study to demonstrate consistent and profound elevation of plasma PTX3 levels in NASH in comparison with non-NASH. The results suggest that plasma PTX3 levels may not only be laboratory values that differentiate NASH from non-NASH, but marker of the severity of hepatic fibrosis in NASH.

Risk factors and mechanisms of non-alcoholic steatohepatitis

The worldwide proportion of overweight and obese individuals has increased yearly for more than a decade. Along with rates of obesity, the incidence of co-morbid conditions such as type 2 diabetes, cardiovascular disease and liver disease has also increased. The form of liver disease associated with obesity is termed non-alcoholic steatohepatitis (NASH) due to the histological similarities to livers of chronic alcoholics. NASH has been observed in adult as well as pediatric populations; however, the etiology of this disease is still unknown. This review outlines some of the risk factors commonly associated with NASH and describes molecular mechanisms proposed to underlie disease pathogenesis.

Change of intestinal mucosa barrier function in the progress of non-alcoholic steatohepatitis in rats

AIM: To explore the change of intestinal mucosa barrier function in the progress of non-alcoholic steatohepatitis (NASH) in rats.

METHODS: Thirty-two Sprague-Dawley (SD) rats were randomly divided into control group and model group. Rats in the control group were given normal diet, and rats in the model group were given fat-rich diet. Eight rats in each group were killed at end of the 8th and 12th wk, respectively. The levels of endotoxin, D-xylose, TG, TC, ALT and AST, intestinal tissue SOD and MDA as well as intestinal mucus secretory IgA (sIgA) were measured. The pathology of liver was observed by HE staining.

RESULTS: At end of the 8th wk, there was no marked difference in the levels of endotoxin, D-xylose and sIgA between the two groups. At end of the 12th wk, rats in the model group developed steatohepatitis and had a higher serum level of endotoxin (P = 0.01) and D-xylose (P = 0.00) and a lower serum level of sIgA (P = 0.007).

CONCLUSION: Intestinal mucosa barrier malfunction may exist in NASH rats and may be an important promoter of NASH in rats.

Pathogenesis of NASH: animal models

The incidence of non-alcoholic steatohepatitis, a disorder linked to visceral adiposity, insulin resistance, dyslipidemia, and type 2 diabetes mellitus, is increasing with the rise in the prevalence of the metabolic syndrome. This review focuses on animal models of steatohepatitis currently used to study (1) the mechanisms regulating hepatic lipid, glucose, and cholesterol homeostasis and (2) inflammatory recruitment and fibrogenesis in the steatotic liver. The ultimate aim of this research is to gain insights into the role of hepatic lipid, inflammation, and fibrosis in human non-alcoholic fatty liver disease.