Role In Steatosis Research Articles

Hepatic macrophage mediated immune response in liver steatosis driven carcinogenesis.

Obesity confers an independent risk for carcinogenesis. Classically viewed as a genetic disease, owing to the discovery of tumor suppressors and oncogenes, genetic events alone are not sufficient to explain the progression and development of cancers. Tumor development is often associated with metabolic and immunological changes. In particular, obesity is found to significantly increase the mortality rate of liver cancer. As its role is not defined, a fundamental question is whether and how metabolic changes drive the development of cancer. In this review, we will dissect the current literature demonstrating that liver lipid dysfunction is a critical component driving the progression of cancer. We will discuss the involvement of inflammation in lipid dysfunction driven liver cancer development with a focus on the involvement of liver macrophages. We will first discuss the association of steatosis with liver cancer. This will be followed with a literature summary demonstrating the importance of inflammation and particularly macrophages in the progression of liver steatosis and highlighting the evidence that macrophages and macrophage produced inflammatory mediators are critical for liver cancer development. We will then discuss the specific inflammatory mediators and their roles in steatosis driven liver cancer development. Finally, we will summarize the molecular pattern (PAMP and DAMP) as well as lipid particle signals that are involved in the activation, infiltration and reprogramming of liver macrophages. We will also discuss some of the therapies that may interfere with lipid metabolism and also affect liver cancer development.

Abstract P048: Steatosis promote liver cancer development by inducing chemokine production from Kupffer cells

Abstract Liver cancer is hallmarked with chronic inflammation resulting from underlying liver diseases such as liver steatosis. Steatotic liver injury recruits inflammatory cells and establishes the tumor immune environment that can promote the development of liver cancer. Previously, we showed that macrophages produce growth factors to promote liver cancer growth in a genetic model where steatosis and liver tumors were induced by the deletion of tumor suppressor Pten (phosphatase and tensin homologue deleted on chromosome 10). In this model, we showed that attenuating steatosis and depletion of macrophages leads to inhibition of liver cancer development. To investigate the recruitment and functions of immune cells in liver cancer, we analyzed the expression profiles of these tumors as well as tumors from other mouse models together with human liver samples. Our analysis of the inflammatory cytokines identified one chemokine that was commonly upregulated in all tumor model and attenuated in non-tumor models. CXCL5 is a member of the neutrophil-activating chemokines. In the Pten deleted liver tumors, CXCL5 is significantly upregulated whereas its expression is inhibited when steatosis is attenuated via caloric restriction or deletion of a metabolic kinase, Akt2. We explored the cell types that may produce CXCL5. To our surprise, the upregulation of CXCL5 is concurrent with increases in macrophage but not neutrophil populations. We further observed significant upregulation of CXCL5 mRNA expression in Kupffer cells, the liver resident macrophages isolated from the Pten deleted mice. We explored the hypothesis that macrophages secrets CXCL5 to establish the tumor environment and promote tumor growth. Our data showed that CXCL5 treatment increased mouse hepatocytes and human HepG2 cells proliferation. This effect is blocked by inhibition of CXCR2, the receptor for CXCL5. Additionally, we explored the mechanisms of CXCL5 upregulation in Kupffer cells and discovered that lipopolysaccharide (LPS) induces the expression of CXCL5 by nearly 20-fold in Kupffer cells. This is in contrast with the lack of induction in murine macrophage cell lines and primary peritoneal macrophages. This unique response of Kupffer cells suggests that the source of CXCL5 in the Pten deletion mouse model is likely Kupffer cells. This data is collaborated by bioinformatic analysis of datasets where steatotic liver injury is induced by diet feeding. Furthermore, analysis of patient proteomic data detected CXCL5 as the primary chemokine that is induced in tumors among other neutrophil-activating peptides. In summary, our data identified CXCL5 as a novel chemokine produced by Kupffer cells that plays key roles in steatosis driven liver cancer development. Chronic liver diseases such as steatohepatitis can establish tumorigenesis environment through accumulation of LPS stimulated CXCL5 release from Kupffer cells. Citation Format: Bangyan L. Stiles, Taojian Tu, Lina He, Mario Alba. Steatosis promote liver cancer development by inducing chemokine production from Kupffer cells [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P048.

Hepatocellular neoplasms arising in genetic metabolic disorders: steatosis is common in both the tumor and background liver

Hepatocellular neoplasms can develop in multiple genetic metabolic disorders. While there have been rare case reports, clinical and pathological characterizations have not been systematically performed. We conducted a retrospective study in 9 patients with these rare genetic metabolic disorders, including glycogen storage disease type 1, ornithine carbamyl transferase deficiency, hereditary tyrosinemia type 1, and Navajo neurohepatopathy, who developed hepatocellular neoplasms. Our results show that steatosis is a common finding in both tumor (6/9 cases, 67%) and background liver parenchyma (8/9 cases, 89%), underlying a possible role for steatosis in tumorigenesis in these genetic metabolic disorders. Our findings also raise a consideration of underlying genetic metabolic disorder when young patients with hepatocellular neoplasm show steatosis in both the tumor and background liver.

A Novel Purification Procedure for Active Recombinant Human DPP4 and the Inability of DPP4 to Bind SARS-CoV-2.

Proteases catalyse irreversible posttranslational modifications that often alter a biological function of the substrate. The protease dipeptidyl peptidase 4 (DPP4) is a pharmacological target in type 2 diabetes therapy primarily because it inactivates glucagon-like protein-1. DPP4 also has roles in steatosis, insulin resistance, cancers and inflammatory and fibrotic diseases. In addition, DPP4 binds to the spike protein of the MERS virus, causing it to be the human cell surface receptor for that virus. DPP4 has been identified as a potential binding target of SARS-CoV-2 spike protein, so this question requires experimental investigation. Understanding protein structure and function requires reliable protocols for production and purification. We developed such strategies for baculovirus generated soluble recombinant human DPP4 (residues 29–766) produced in insect cells. Purification used differential ammonium sulphate precipitation, hydrophobic interaction chromatography, dye affinity chromatography in series with immobilised metal affinity chromatography, and ion-exchange chromatography. The binding affinities of DPP4 to the SARS-CoV-2 full-length spike protein and its receptor-binding domain (RBD) were measured using surface plasmon resonance and ELISA. This optimised DPP4 purification procedure yielded 1 to 1.8 mg of pure fully active soluble DPP4 protein per litre of insect cell culture with specific activity >30 U/mg, indicative of high purity. No specific binding between DPP4 and CoV-2 spike protein was detected by surface plasmon resonance or ELISA. In summary, a procedure for high purity high yield soluble human DPP4 was achieved and used to show that, unlike MERS, SARS-CoV-2 does not bind human DPP4.

Expression of Notch family is altered in non‑alcoholic fatty liver disease

The aim of the present study was to explore the dynamic relationship between Notch and non-alcoholic fatty liver disease (NAFLD), both in vitro and in vivo. The LX2, Huh7 and MIHA hepatic cell lines were used to establish a cell steatosis model induced by palmitic acid (PA) at different concentrations (0.1, 0.25 and 0.5 mM). Cell proliferation and migration were assessed using a 5-bromo-2′-deoxyuridine kit and a wound healing assay. The dosage of 0.25 mM PA for 36–48 h treatment was chosen for subsequent experiments. Steatotic cells were identified by Oil Red O staining. Feeding mice a methionine-choline-deficient (MCD) diet is known induce a model of NAFLD, compared with a methionine-choline-sufficient (MCS) diet. Therefore, Notch family mRNA expression was evaluated in the liver of MCD-fed mice at varying time points (days 5, 10, 21 and 70) using reverse transcription-quantitative PCR. Notch expression levels were also assessed in cell lines at 12, 24, 36 and 48 h after PA treatment. Notch signaling molecules changed in the PA or MCD model over time. In vitro, the mRNA levels of Notch1, −2 and −4 increased in all cell lines after 12-h PA treatment. At 24 h, these genes were upregulated only in LX2 cells, while showing a ‘down-up’ pattern in MIHA cells (i.e. these genes were downregulated at 24 h but upregulated at 36 h). However, expression of Notch1, −2, −3 and −4 mRNA rose significantly in the early stage (day 10) of NAFLD. At week 3, the levels of Notch1 and −2 were higher in the MCD group than in the MCS group, while the reverse was observed for Notch3 and −4. Expression of these four genes increased again in the late stage (day 70) of NAFLD. Therefore, these results indicated that Notch family members Notch1-4 were involved in the development of NAFLD and played an important role in steatosis in this model.

Disruption of hepatic small heterodimer partner induces dissociation of steatosis and inflammation in experimental nonalcoholic steatohepatitis

Disruption of hepatic small heterodimer partner induces dissociation of steatosis and inflammation in experimental nonalcoholic steatohepatitis

Disruption of hepatic small heterodimer partner induces dissociation of steatosis and inflammation in experimental nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease worldwide and is characterized by steatosis, inflammation, and fibrosis. The molecular mechanisms underlying NASH development remain obscure. The nuclear receptor small heterodimer partner (Shp) plays a complex role in lipid metabolism and inflammation. Here, we sought to determine SHP's role in regulating steatosis and inflammation in NASH. Shp deletion in murine hepatocytes (Shp Hep-/-) resulted in massive infiltration of macrophages and CD4+ T cells in the liver. Shp Hep-/- mice developed reduced steatosis, but surprisingly increased hepatic inflammation and fibrosis after being fed a high-fat, -cholesterol, and -fructose (HFCF) diet. RNA-Seq analysis revealed that pathways involved in inflammation and fibrosis are significantly activated in the liver of Shp Hep-/- mice fed a chow diet. After having been fed the HFCF diet, WT mice displayed up-regulated peroxisome proliferator-activated receptor γ (Pparg) signaling in the liver; however, this response was completely abolished in the Shp Hep-/- mice. In contrast, livers of Shp Hep-/- mice had consistent NF-κB activation. To further characterize the role of Shp specifically in the transition of steatosis to NASH, mice were fed the HFCF diet for 4 weeks, followed by Shp deletion. Surprisingly, Shp deletion after steatosis development exacerbated hepatic inflammation and fibrosis without affecting liver steatosis. Together, our results indicate that, depending on NASH stage, hepatic Shp plays an opposing role in steatosis and inflammation. Mechanistically, Shp deletion in hepatocytes activated NF-κB and impaired Pparg activation, leading to the dissociation of steatosis, inflammation, and fibrosis in NASH development.

Hepatic Steatosis Is Highly Prevalent but Is Not Correlated With Advanced Fibrosis in Autoimmune Hepatitis: Results Obtained at the Autoimmune Hepatitis Association National Meeting

Introduction: Obesity and associated steatosis are unfavorable prognostic factors in viral hepatitis. A recent report suggested that coexisting fatty liver disease may adversely affect the natural history of patients with autoimmune hepatitis in a similar fashion. We conducted a study to examine the prevalence of hepatic steatosis in individuals with autoimmune hepatitis. Methods: Vibration-controlled transient elastography (Fibroscan) was offered to patients with autoimmune hepatitis (AIH) at the Autoimmune Hepatitis Association (AIHA) national meeting in June 2017 in Indianapolis. All participants were fasting for 3 hours prior to examination. Based on the NASH CRN criteria for 90% sensitivity, presence of hepatic steatosis was defined as Continuous Attenuation Parameter (CAP) ≥ 263 dB/m and severe hepatic steatosis as CAP score ≥ 274 dB/m. The presence of compensated advanced chronic liver disease (cACLD) was defined as: liver stiffness measurement (LSM) > 15 kPa as highly suggestive, 10-15 kPa) as suggestive and < 10 kPa as unlikely. Results: 221 participants attended the AIHA conference in which 148 (67%) carried the diagnosis of AIH and 73 (33%) were caregivers. In total, 74 (50%) participants with AIH (8% male and 92% female) completed Fibroscan examination. This group had a median age of 48 years (yrs) and BMI 29 kg/m2. The median liver stiffness and CAP scores of all participants was 6.8 kPa and 236 dB/m, respectively. 22 (30%) patients had steatosis whereas 19 (26%) severe steatosis. Individuals with both steatosis and severe steatosis had higher BMI (32.6 kg/m2, 32.9 kg/m2) compared to those without steatosis (26.8 kg/m2, p=0.01). Patients with steatosis (50 yrs) also tended to be older compared to those without steatosis (47 yrs, p=0.09). According to the parameters of cACLD, 11 (15%) individuals were highly suggestive, 12 (16%) were suggestive, and 51 (69%) had no evidence of cACLD. Advanced fibrosis was more likely in participants that were male (67% vs 28%, p=0.07) and had higher BMI (31 kg/m2 vs 27.1 kg/m2, p=0.02). There was no significant correlation between advanced fibrosis and the presence of steatosis (r=0.17, p=0.3) or severe steatosis (r=0.18, p=0.3). Conclusion: In patients with AIH there is high prevalence of any steatosis or severe steatosis, but lack of their correlation with advanced fibrosis argues against a role for steatosis in worsening fibrosis in patients with AIH.946_C Figure 3. Liver Cancer Death Rate946_B Figure 2. GI Fellowships

Angiogenic factor with G patch and FHA domains 1 (Aggf1) promotes hepatic steatosis in mice

Increased uptake of nutrients coupled with reduced activity leads to the development of a host of metabolic disorders in humans. In the present study we examined the role of angiogenic factor with G patch and FHA domains 1 (Aggf1) in the pathogenesis of steatosis, characterized by accumulation of lipids in the liver and consequently hepatic insulin resistance. We report here that Aggf1 expression was up-regulated in the liver in both genetically predisposed and diet-induced mouse model of steatosis. Aggf1 expression was also stimulated by free fatty acids in primary hepatocytes. Over-expression of Aggf1 in mice promoted steatosis. On the contrary, Aggf1 depletion ameliorated steatosis in mice. Mechanistically, Aggf1 activated the expression of gluconeogenesis gene and skewed the insulin signaling pathway to induce insulin resistance. Taken together, our data suggest that Aggf1 plays a role in steatosis in vivo and as such may be a new target in the development of therapeutics solutions against steatosis.

Abstract 63: A transposon-based forward genetic screen for steatosis-associated liver cancer drivers

Abstract Hepatocellular carcinoma (HCC), or liver cancer, is the second leading cause of death from cancer worldwide (Ferlay et al, Lyon, France: International Agency for Research on Cancer, 2013). HCC is linked with hepatic steatosis, or fatty liver disease, the most common chronic liver disease in the US. Both hepatic steatosis and HCC are increasing in prevalence in the US. However, the molecular mechanisms that cause HCC in a steatotic liver are not entirely understood. To uncover mutations promoting cancer in fatty livers and elucidate the role of steatosis in HCC, we performed a forward genetic screen using the conditional Sleeping Beauty (SB) transposon insertional mutagenesis system in mice treated with ethanol and a choline deficient diet to induce steatosis. Mice developed hepatic steatosis and liver cancer without sex bias, modeling the pattern seen in humans in whom HCC's with steatosis as a preceding condition are represented by a nearly equal number of males and females. We found that hepatic steatosis caused a downregulation of liver Foxa1 expression and increased Foxa2 inactivating phosphorylation, thus providing a molecular explanation for the loss of gender bias in our mouse model. Transposon insertion sites were mapped from the mouse HCC tumors, and genes near or in which more insertions were observed than expected by chance were identified as common insertion sites (CIS), which we consider putative steatosis-associated liver cancer genes. Wnt/b-catenin signaling, which defines a subclass of HCC and can induce tumors in mice without sex bias, was one of the top CIS associated pathways identified. Interestingly, alpha-adrenergic and dopamine signaling were also among the top steatosis-specific CIS associated pathways, suggesting a role for the sympathetic nervous system and cAMP signaling in fatty liver-associated cancer. Further studies are underway to test the roles of the pathways and individual genes identified in this study in driving HCC. Our studies implicate Wnt/beta-catenin and sympathetic nervous system signaling in steatosis-associated HCC and suggest methods for treatment or prevention in such cases. Citation Format: Barbara R. Tschida, N. Alpay Temiz, Ju D. Yang, Vincent W. Keng, David A. Largaespada. A transposon-based forward genetic screen for steatosis-associated liver cancer drivers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 63.

Role of the receptor tyrosine kinase MER in the development of fibrosis in NAFLD

s / Digestive and Liver Disease 47S (2015) e221–e225 e225 age of these patients was 61 years (SD 12); 53% were female. Compared to HCV patients without steatosis (3347), in patients with steatosis: BMI was ≥25 in 44% vs. 36% (p<0.05) and ≥30 in 18% vs 11% (p=0.05); F4/cirrhosis was present in 28% vs. 32% (p=ns). Among HCV patients with and without steatosis, similar distribution of HCV genotypes, transaminases and gamma GT levels, lipid pattern and other comorbidities were observed. Of 1295 patients with steatosis, in 167 (1.3%) liver biopsy was available and confirmed the NAFLD diagnosis. In this last group of patients the prevalence of diabetes and of cardiovascular disease were higher compared to patients without steatosis (18% vs 11% (p<0.05) and 35% vs 31% p=ns) and to patients with diagnosis of steatosis diagnosed only by US. Conclusion: The single evaluation of US steatosis is not a helpful factor that could predict liver disease progression and/or specific comorbidities. PITER could be a useful cohort in which the role of steatosis could be prospectively evaluated through an additive diagnostic data set. Better definition of NAFLD markers and their validation in the PITER cohort compared to data derived by a dedicated NAFLD/NASH cohort is worth to be addressed. http://dx.doi.org/10.1016/j.dld.2015.07.022

Protective Effect of the Y220C Mutant p53 Against Steatosis: Good News?

Nonalcoholic fatty liver disease (NAFLD) ranges from simple steatosis to steatohepatitis, which may progress to fibrosis, and cirrhosis, leading eventually to hepatocarcinoma development. Recently, cases of hepatocarcinoma have been diagnosed in steatotic patients without nonalcoholic steatohepatitis (NASH) and cirrhosis. The p53 protein, besides its function as tumor suppressor, is emerging as an important regulator of cellular metabolism, but its role in steatosis remains unclear. We induced steatosis in HepG2 (wt-p53) and Huh7.5.1 (Y220C-mutant p53) cells using free fatty acids. We observed a different modulation of p53, different intracellular lipid content, and similar down-regulation of the de novo lipid synthesis genes but opposite modulation of the fatty acid β-oxidation pathway between HepG2 and Huh7.5.1. Accordingly, we found a diverse amount of apoptosis and reactive oxygen species between the two cell lines. Transfection of the wt-p53 in Huh7.5.1 cells reverted the different lipid metabolism behavior observed in these cells. In conclusion, unlike the wt-p53, the Y220C mutant provides a specific protection against steatosis and potentially against its progression. Our findings highlight for the first time an unknown role of a p53 mutant in the setting of steatosis. Being this mutation very frequent in human cancers, this study could be a breakthrough in explaining the occurrence of hepatocarcinoma in steatotic patients without NASH and cirrhosis.

The Role of Steatosis in HBsAg Seroclearance for Patients with Chronic Hepatitis B Infection: Fact or Fiction?

In the Asia Pacific region, chronic hepatitis B (CHB) is an endemic infection, and is the most important cause of cirrhosis and hepatocellular carcinoma (HCC). The understanding of the natural history of CHB through large longitudinal population studies has been pivotal in identifying risk factors which are important for disease progression [1, 2]. Well-established risk factors include host factors, such as age and gender, and viral factors, such as genotype and viral load. The interplay between other types of liver diseases and CHB is less well studied. Non-alcoholic fatty liver disease (NAFLD), an entity which has traditionally been associated with Western populations, is now becoming more prevalent in many parts of Asia. This is partly due to the rising prevalence of obesity in the Asia Pacific countries. Therefore, it is unavoidable that there will be an increasing trend of NAFLD co-existing with other liver diseases. The effects of NAFLD on viral hepatitis have been described mainly in patients with chronic hepatitis C. In this setting, the presence of steatosis can potentially accelerate fibrogenesis, increase the risk of cirrhosis and hepatocellular carcinoma (HCC), and reduce the efficacy of antiviral therapy [3].

Stress management: How the unfolded protein response impacts fatty liver disease

Induction of the unfolded protein response (UPR) is recognized as central to fatty liver disease (FLD) pathophysiology. This pathway may be a potential therapeutic target for FLD, as well as other diseases. However, fundamental questions as to how UPR contributes to FLD remain unanswered. Conflicting data suggest that this pathway can both protect against and augment this disease. Here, we review the relationship between protein secretion, endoplasmic reticulum function (ER), and UPR activation. The UPR serves to maintain secretory pathway homeostasis by enhancing the protein folding environment in the ER, and we review data investigating the role for individual UPR players in fatty liver (steatosis). We explore a novel concept in the field that all cases of UPR activation do not equal "ER stress". Rather, different types of UPRs that can either protect against or cause FLD are discussed. Refining our current understanding of this complex pathway is particularly important, as drugs that affect the protein folding environment in the ER and affect UPR activation are being successful in clinical trials for FLD.

Hepatocyte-specific Deletion of Janus Kinase 2 (JAK2) Protects against Diet-induced Steatohepatitis and Glucose Intolerance

Non-alcoholic fatty liver disease (NAFLD) is becoming the leading cause of chronic liver disease and is now considered to be the hepatic manifestation of the metabolic syndrome. However, the role of steatosis per se and the precise factors required in the progression to steatohepatitis or insulin resistance remain elusive. The JAK-STAT pathway is critical in mediating signaling of a wide variety of cytokines and growth factors. Mice with hepatocyte-specific deletion of Janus kinase 2 (L-JAK2 KO mice) develop spontaneous steatosis as early as 2 weeks of age. In this study, we investigated the metabolic consequences of jak2 deletion in response to diet-induced metabolic stress. To our surprise, despite the profound hepatosteatosis, deletion of hepatic jak2 did not sensitize the liver to accelerated inflammatory injury on a prolonged high fat diet (HFD). This was accompanied by complete protection against HFD-induced whole-body insulin resistance and glucose intolerance. Improved glucose-stimulated insulin secretion and an increase in β-cell mass were also present in these mice. Moreover, L-JAK2 KO mice had progressively reduced adiposity in association with blunted hepatic growth hormone signaling. These mice also exhibited increased resting energy expenditure on both chow and high fat diet. In conclusion, our findings indicate a key role of hepatic JAK2 in metabolism such that its absence completely arrests steatohepatitis development and confers protection against diet-induced systemic insulin resistance and glucose intolerance.

Activating transcription factor 6 plays protective and pathological roles in steatosis due to endoplasmic reticulum stress in zebrafish

Many etiologies of fatty liver disease (FLD) are associated with the hyperactivation of one of the three pathways composing the unfolded protein response (UPR), which is a harbinger of endoplasmic reticulum (ER) stress. The UPR is mediated by pathways initiated by PRKR-like endoplasmic reticulum kinase, inositol-requiring 1A/X box binding protein 1, and activating transcription factor 6 (ATF6), and each of these pathways has been implicated to have a protective or pathological role in FLD. We used zebrafish with FLD and hepatic ER stress to explore the relationship between Atf6 and steatosis. A mutation of the foie gras (foigr) gene caused FLD and hepatic ER stress. The prolonged treatment of wild-type larvae with tunicamycin (TN), which caused chronic ER stress, phenocopied foigr. In contrast, acute exposure to a high dose of TN robustly activated the UPR but was less effective at inducing steatosis. The sterol regulatory element binding protein transcription factors were not required for steatosis in any of these models. Instead, depleting larvae of active Atf6 either through a membrane-bound transcription factor peptidase site 1 mutation or an atf6 morpholino injection protected them against steatosis caused by chronic ER stress, but exacerbated steatosis caused by acute TN treatment. ER stress causes FLD. A loss of Atf6 prevents steatosis caused by chronic ER stress but can also potentiate steatosis caused by acute ER stress. This demonstrates that Atf6 can play both protective and pathological roles in FLD.

The pathological role of visceral fat accumulation in steatosis, inflammation, and progression of nonalcoholic fatty liver disease

Our previous studies have indicated a close association between visceral fat accumulation and hepatic steatosis in nonalcoholic fatty liver disease (NAFLD). This study investigated whether visceral fat accumulation was related to the pathogenesis and disease progression of nonalcoholic steatohepatitis (NASH)/NAFLD. First, a total of 550 subjects who underwent a health checkup and measurement of visceral fat accumulation, done with a bioelectrical impedance analyzer (X-SCAN; Owa Medical, Fukuoka, Japan), were included. The relationship between visceral fat accumulation and biochemical parameters was examined. Second, a total of 74 patients with NASH/NAFLD who underwent liver biopsy were reviewed. Visceral fat accumulation was determined by abdominal computed tomography. The association between visceral fat accumulation and the histopathological grade/stage determined by the NAFLD activity score and Brunt's classification was evaluated. There was a significant relationship between visceral fat accumulation and glucose, triglyceride, and alanine aminotransferase (ALT; r = 0.423, P < 0.01). In stepwise regression analysis, visceral fat area (VFA), serum triglyceride level, and serum low-density lipoprotein (LDL)-cholesterol level were selected as predictor variables for serum ALT level, in a continuous manner (serum ALT level = -1.359 + 0.143 × VFA + 0.046 × triglyceride + 0.059 × LDL, R(2) = 0.217, P < 0.001). In patients with NASH, there was no correlation between histological grade and the visceral fat volume. Visceral fat accumulation in patients with stage 3/4 advanced NASH was greater than that in patients with stage 1/2 early NASH (P < 0.05). These results suggest that visceral fat accumulation plays a role in steatosis and fibrosis in the pathogenesis and prognosis of NAFLD.

The role of steatosis of the liver graft in the development of post-transplant biliary complications

The role of steatosis of the liver graft in the development of post-transplant biliary complications

Fenofibrate and PBA prevent fatty acid-induced loss of adiponectin receptor and pAMPK in human hepatoma cells and in hepatitis C virus-induced steatosis

Adiponectin receptors play a key role in steatosis and inflammation; however, very little is known about regulation of adiponectin receptors in liver. Here, we examined the effects of palmitate loading, endoplasmic reticulum (ER) stress, and the hypolipidemic agent fenofibrate on adiponectin receptor R2 (AdipoR2) levels and AMP-activated protein kinase (AMPK) in human hepatoma Huh7 cells and in Huh.8 cells, a model of hepatitis C-induced steatosis. Palmitate treatment reduced AdipoR2 protein and basal AMPK phosphorylation in Huh7 cells. Fenofibrate treatment preserved AdipoR2 and phosphorylated AMPK (pAMPK) levels in palmitate-treated cells accompanied by reduced triglyceride (TG) accumulation and less activation of ER stress markers CCAAT/enhancer binding (C/EBPbeta) and eukaryotic translation initiation factor 2 alpha. ER stress agents thapsigargin and tunicamycin suppressed AdipoR2 and pAMPK levels in Huh7 cells, while fenofibrate and the chemical chaperone 4-phenylbutyrate (PBA) prevented these changes. AdipoR2 levels were lower in Huh.8 cells and fenofibrate treatment increased AdipoR2 while reducing activation of c-Jun N-terminal kinase and C/EBPbeta expression without changing TG levels. Taken together, these results suggest that fatty acids and ER stress reduce AdipoR2 protein and pAMPK levels, while fenofibrate and PBA might be important therapeutic agents to correct lipid- and ER stress-mediated loss of AdipoR2 and pAMPK associated with nonalcoholic steatohepatitis.

Persistently normal alanine aminotransferase levels in HIV/HCV‐coinfected patients: the role of steatosis

The frequency and significance of, and liver biopsy findings associated with, a persistently normal alanine aminotransferase (ALT) level in HIV/hepatitis C virus (HCV)-coinfected patients are poorly characterized. We analysed factors associated with persistently normal ALT levels, defined as at least three consecutive normal ALT values over a 6-month period, in a group of 381 HIV/HCV-coinfected patients. Patients were categorized into two groups according to ALT values: group 1, patients with persistently normal ALT levels; and group 2, patients with elevated ALT values. Possible interactions with host factors, HIV and HCV viral factors, antiretroviral treatment and histological features were examined. Thirty-six patients (9.4%) had persistently normal ALT levels. None of the 36 patients had cirrhosis. Seven patients (19.4%) had a METAVIR fibrosis score of F3. In multivariate analysis, a lower mean METAVIR inflammation score [odds ratio (OR) 0.50, 95% confidence interval (CI) 0.28-0.89; P=0.017], the absence of steatosis (OR 0.43, 95% CI 0.20-0.90; P=0.026) and HCV genotype 4 infection (OR 2.81, 95% CI 1.15-6.68; P=0.023) were associated with persistently normal ALT levels. The slower progression of chronic hepatitis in patients with persistently normal ALT levels could be related, in part, to a lower frequency of steatosis.