Luca Miele

Increased intestinal permeability and tight junction alterations in nonalcoholic fatty liver disease

The role played by the gut in nonalcoholic fatty liver disease (NAFLD) is still a matter of debate, although animal and human studies suggest that gut‐derived endotoxin may be important. We investigated intestinal permeability in patients with NAFLD and evaluated the correlations between this phenomenon and the stage of the disease, the integrity of tight junctions within the small intestine, and prevalence of small intestinal bacterial overgrowth (SIBO). We examined 35 consecutive patients with biopsy‐proven NAFLD, 27 with untreated celiac disease (as a model of intestinal hyperpermeability) and 24 healthy volunteers. We assessed the presence of SIBO by glucose breath testing (GBT), intestinal permeability by means of urinary excretion of 51Cr‐ethylene diamine tetraacetate (51Cr‐EDTA) test, and the integrity of tight junctions within the gut by immunohistochemical analysis of zona occludens‐1 (ZO‐1) expression in duodenal biopsy specimens. Patients with NAFLD had significantly increased gut permeability (compared with healthy subjects; P < 0.001) and a higher prevalence of SIBO, although both were lower than in the untreated celiac patients. In patients with NAFLD, both gut permeability and the prevalence of SIBO correlated with the severity of steatosis but not with presence of NASH. Conclusions: Our results provide the first evidence that NAFLD in humans is associated with increased gut permeability and that this abnormality is related to the increased prevalence of SIBO in these patients. The increased permeability appears to be caused by disruption of intercellular tight junctions in the intestine, and it may play an important role in the pathogenesis of hepatic fat deposition. (HEPATOLOGY 2009.)

Prognostic factors for survival in patients with early-intermediate hepatocellular carcinoma undergoing non-surgical therapy: comparison of Okuda, CLIP, and BCLC staging systems in a single Italian centre.

Background: Several prognostic models have been developed to stage hepatocellular carcinoma (HCC) but there is no general consensus on which is the most reliable. We compared three prognostic indices (Okuda, CLIP, and BCLC scoring systems) in a large series of cirrhotic patients with HCC undergoing non-surgical treatment in terms of their ability to classify patients into different risk groups Methods: We retrospectively studied 268 Italian patients with HCC. A total of 146 patients were treated with ablation, 132 with percutaneous ethanol injection, and 14 with radiofrequency ablation; 103 underwent transcatheter arterial chemoembolisation and 19 had supportive care alone. Factors determining survival were analysed by univariate and multivariate analysis using the Kaplan-Meier method and Cox proportional hazard regression models. Okuda, CLIP, and BCLC scores evaluated before treatment were applied. Results: Median survival was 25.7 months. In a multivariate analysis, portal vein thrombosis, α fetoprotein, total bilirubin, and tumour size were significant predictors of survival. Okuda, CLIP, and BCLC scores were all able to predict survival (p<0.001). They identified two, four, and six risk groups, respectively, with a median survival ranging from 27 to 19 months for Okuda, 30 to 5 months for CLIP, and 43 to 7 months for BCLC. Conclusions: Both CLIP and BCLC scores were more effective than the Okuda score in stratifying patients into different risk groups with early-intermediate HCC. However, the BCLC scoring system gave a better prediction of prognosis in patients with disease diagnosis at a very early stage.

The Liver May Act as a Firewall Mediating Mutualism Between the Host and Its Gut Commensal Microbiota

The liver forms a firewall that protects against vascular-borne gut microbes and is commonly impaired in liver disease. Breaching Barriers Premature death from chronic liver disease is a rising global trend. Opportunistic bacterial infections caused by beneficial microbes that have breached the gut and its immune barrier often lead to death in liver cirrhosis patients. Balmer et al. now show that the liver forms a second vascular barrier for eliminating commensal bacteria that have escaped from the gut. In animal models of liver disease and gut dysfunction and in patients with nonalcoholic steatohepatitis, the liver is unable to capture escaped gut commensal bacteria, which then leak into the systemic circulation, resulting in a robust host nonmucosal immune response and the breakdown of mutualism between the host and its gut microbiota. Mutualism breakdown is an important complication of liver disease. A prerequisite for establishment of mutualism between the host and the microbial community that inhabits the large intestine is the stringent mucosal compartmentalization of microorganisms. Microbe-loaded dendritic cells trafficking through lymphatics are arrested at the mesenteric lymph nodes, which constitute the firewall of the intestinal lymphatic circulation. We show in different mouse models that the liver, which receives the intestinal venous blood circulation, forms a vascular firewall that captures gut commensal bacteria entering the bloodstream during intestinal pathology. Phagocytic Kupffer cells in the liver of mice clear commensals from the systemic vasculature independently of the spleen through the liver’s own arterial supply. Damage to the liver firewall in mice impairs functional clearance of commensals from blood, despite heightened innate immunity, resulting in spontaneous priming of nonmucosal immune responses through increased systemic exposure to gut commensals. Systemic immune responses consistent with increased extraintestinal commensal exposure were found in humans with liver disease (nonalcoholic steatohepatitis). The liver may act as a functional vascular firewall that clears commensals that have penetrated either intestinal or systemic vascular circuits.

The Kruppel-Like Factor 6 Genotype Is Associated With Fibrosis in Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS Although nonalcoholic fatty liver disease (NAFLD) is increasingly common, only a minority of affected individuals develop fibrotic liver disease. Based on its role in liver growth and repair, we explored whether Kruppel-like factor 6 (KLF6) plays a role in NAFLD progression. METHODS KLF6 expression in 31 fibrosis scored NAFLD liver biopsy specimens was assessed by real-time polymerase chain reaction. Transfected minigene constructs were used to study the effect of a polymorphism, KLF6-IVS1-27G>A, that promotes KLF6 alternative splicing in vitro. We genotyped KLF6-IVS1-27G>A in 3 groups of patients (UK group 1, n = 306; Italian group 2, n = 109; trio group 3, n = 61 children and parents). RESULTS KLF6 expression was increased in association with increased steatosis, inflammation, and fibrosis in NAFLD livers. KLF6-IVS1-27G>A promoted alternative splicing of KLF6 and abrogated the up-regulation of both alpha-smooth muscle actin and collagen 1 in LX-2 cells. Group 1 genotyping identified KLF6-IVS1-27G>A in 44 of 306 (14.4%) patients. Notably, KLF6-IVS1-27G>A was associated significantly with milder NAFLD, with only 25% having more advanced fibrosis compared with 45% of wild-type (wt) individuals. This trend was confirmed in group 2. A linear regression analysis including all 415 patients, adjusted for age, sex, body mass index, and blood glucose level, confirmed that presence of the wt KLF6 allele was an independent predictor of fibrotic NAFLD. Furthermore, we have shown preferential transmission of the wt allele to children with fibrotic NAFLD. CONCLUSIONS We report a functional polymorphism in the KLF6 gene associated with advanced NAFLD and believe further study of KLF6 may enhance our understanding of this disease process.

Prevalence, characteristics and severity of non-alcoholic fatty liver disease in patients with chronic plaque psoriasis

BACKGROUND/AIMS The association between NAFLD and psoriasis has never been explored in prospective epidemiological studies. The aim of this 2-phase study was to study the clinical features of NAFLD in patients with psoriasis. METHODS Phase 1: Investigation of prevalence and characteristics of NAFLD in an unselected cohort of 142 adult Italian outpatients with psoriasis vulgaris. Phase 2: Comparison of the psoriasis cohort subgroup with NAFLD and an age- and body mass index-matched retrospective cohort of 125 non-psoriasis patients with biopsy proven NAFLD. RESULTS Based on histories, laboratory tests, and ultrasound studies, 84 (59.2%) received clinical diagnosis of NAFLD; 30 had factors potentially associated with liver disease other than NAFLD (e.g., viral hepatitis, significant ethanol, methotrexate use); and 28 (19.7%) had normal livers. Comparison of the normal-liver and NAFLD subgroups revealed that NAFLD in psoriasis patients (Ps-NAFLD) was significantly correlated with metabolic syndrome (p<0.05); obesity (p=0.043); hypercholesterolemia (p=0.029); hypertriglyceridemia (p<0.001); AST/ALT ratio >1 (p=0.019), and psoriatic arthritis (PsA) (p=0.036). The association with PsA remained significant after logistic regression analysis (OR=3.94 [CI, 1.07-14.46]). Compared with the retrospective non-psoriatic NAFLD cohort (controls), Ps-NAFLD patients (cases) were likely to have severe NAFLD reflected by non-invasive NAFLD Fibrosis Scores and AST/ALT >1. CONCLUSIONS NAFLD is highly prevalent among psoriasis patients, where it is closely associated with obesity (overall and abdominal), metabolic syndrome, and PsA, and more likely to cause severe liver fibrosis (compared with nonPs-NAFLD). Routine work-up for NAFLD may be warranted in patients with psoriasis, especially when potentially hepatotoxic drug therapy is being considered.

Silybin combined with phosphatidylcholine and vitamin E in patients with nonalcoholic fatty liver disease: A randomized controlled trial

The only currently recommended treatment for nonalcoholic fatty liver disease (NAFLD) is lifestyle modification. Preliminary studies of silybin showed beneficial effects on liver function. Realsil (RA) comprises the silybin phytosome complex (silybin plus phosphatidylcholine) coformulated with vitamin E. We report on a multicenter, phase III, double-blind clinical trial to assess RA in patients with histologically documented NAFLD. Patients were randomized 1:1 to RA or placebo (P) orally twice daily for 12 months. Prespecified primary outcomes were improvement over time in clinical condition, normalization of liver enzyme plasma levels, and improvement of ultrasonographic liver steatosis, homeostatic model assessment (HOMA), and quality of life. Secondary outcomes were improvement in liver histologic score and/or decrease in NAFLD score without worsening of fibrosis and plasma changes in cytokines, ferritin, and liver fibrosis markers. We treated 179 patients with NAFLD; 36 were also HCV positive. Forty-one patients were prematurely withdrawn and 138 patients analyzed per protocol (69 per group). Baseline patient characteristics were generally well balanced between groups, except for steatosis, portal infiltration, and fibrosis. Adverse events (AEs) were generally transient and included diarrhea, dysgeusia, and pruritus; no serious AEs were recorded. Patients receiving RA but not P showed significant improvements in liver enzyme plasma levels, HOMA, and liver histology. Body mass index normalized in 15% of RA patients (2.1% with P). HCV-positive patients in the RA but not the P group showed improvements in fibrogenesis markers. This is the first study to systematically assess silybin in NAFLD patients. Treatment with RA but not P for 12 months was associated with improvement in liver enzymes, insulin resistance, and liver histology, without increases in body weight. These findings warrant further investigation.

Review article: breath testing for human liver function assessment

Carbon‐labelled breath tests were proposed as tools for the evaluation of human liver function 30 years ago, but have never become part of clinical routine. One reason for this is the complex role of the liver in metabolic regulation, making it difficult to provide essential information for the management of patients with liver disease with a single test and to satisfy the hepatology community. As a result, a battery of breath tests have been developed. Depending on the test compound administered, different metabolic pathways (microsomal, cytosolic, mitochondrial) can be examined. Most available data come from microsomal function tests, whilst information about cytosolic and mitochondrial liver function is more limited. However, breath tests have shown promise in some studies, in particular to predict the outcome of patients with chronic liver disease or to monitor hepatic function after treatment. Whilst we await new substrates that can be used to measure liver function in a more valid manner, and large prospective studies to assess the usefulness of available test compounds, the aim of this review is to describe how far we have come in this controversial and unresolved issue.

A 360-degree overview of paediatric NAFLD: Recent insights

Non-alcoholic fatty liver disease (NAFLD) is a multi-faceted disorder, which ranges from simple steatosis to non-alcoholic steatohepatitis (NASH) with/without fibrosis. The effects of specific risk factors, such as obesity and sedentary lifestyle, on predisposing genetic settings eventually lead to the development of NAFLD in children. The complex interplay between genes and environment in NAFLD pathogenesis is sustained by multiple mechanisms that involve liver crosstalk with other organs and tissues, especially gut and adipose tissue. Unfortunately, natural history of paediatric NAFLD is lacking, and the etiopathogenesis is still in the process of being defined. Potential early predictors and suitable non-invasive diagnostic tools can be discovered based on the pathogenetic mechanisms and histological patterns. This will also help design novel treatments and a comprehensive and successful management strategy for patients. In this review, we discuss the recent advances made in genetics, etiopathogenesis, diagnosis, and therapeutic management of NAFLD, focusing especially on the obesity-related steatotic liver condition.

Nonalcoholic Fatty Liver Disease as a Contributor to Hypercoagulation and Thrombophilia in the Metabolic Syndrome

Nonalcoholic fatty liver disease (NAFLD), comprising its whole spectrum of conditions ranging from simple steatosis to steatohepatitis (nonalcoholic steatohepatitis; NASH) and cirrhosis, is the most frequent liver disease in developed countries and is now regarded as the liver manifestation of the metabolic syndrome. Several studies indicate that NAFLD, especially in its necro-inflammatory form (NASH), is associated with a systemic proinflammatory/prothrombotic state, independently of shared metabolic risk factors. This suggests that NAFLD/NASH is not simply a marker of the proinflammatory/prothrombotic state in the metabolic syndrome but is actively involved in its pathogenesis, possibly through the systemic release of proinflammatory and procoagulant factors from the steatotic liver (C-reactive protein, plasminogen activator inhibitor-1, interleukin-6, fibrinogen, and other proinflammatory cytokines). The clinical impact of NAFLD on the proinflammatory/prothrombotic risk profile deserves particular attention in view of the implications for screening and surveillance strategies in the growing number of patients with NAFLD.

High efficacy of 1‐week doxycycline‐ and amoxicillin‐based quadruple regimen in a culture‐guided, third‐line treatment approach for Helicobacter pylori infection

Background : Helicobacter pylori infection may persist after both first‐ and second‐line current treatments.