Importance of cytokines, oxidative stress and expression of BCL-2 in the pathogenesis of non-alcoholic steatohepatitis

Combination of two-photon fluorescent probes for carboxylesterase and ONOO- to visualize the transformation of nonalcoholic fatty liver to nonalcoholic steatohepatitis in liver orthotopic imaging

As the most common cause of liver diseases, nonalcoholic fatty liver disease (NAFLD) can be classified into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). While NAFL is generally benign, the transition from NAFL to NASH is a cardinal feature of the non-benign liver disease that leads to cirrhosis and cancer, which indicates that tracking the transformation of NAFL to NASH timely is significant for precision management of liver diseases. Therefore, two fluorescent probes (CNFCl and DRNO) have been developed to visualize this pathological event. α-Fluorochloroacetamide and α-ketoamide was employed as the recognition site for carboxylesterase (CE) in CNFCl and peroxynitrite (ONOO-) in DRNO, respectively. CNFCl (λem = 445 nm) and DRNO (λem = 560 nm) showed high specificity and sensitivity towards CE and ONOO- respectively. By incubating with CE/ONOO- for 0.5 h respectively, both the emission intensity of CNFCl (linear range: 0-0.2 U/mL) and DRNO (linear range: 0-17.5 μM) displayed significant enhancement. As a result, the detection limit of CNFCl and DRNO for CE and ONOO- was calculated as 4.2 mU/L and 0.05 μM respectively. More importantly, the emission spectra of CNFCl and DRNO in the presence of CE and ONOO- respectively were cross-talk free under the two-photon excitation of 720 nm. This greatly facilitated the simultaneous detection of CE and ONOO- at distinctive channel, thus ensuring the high fidelity of the detection. These two probes were combined to image the fluctuation of CE and ONOO- during the conversion of NAFL to NASH in vitro and in vivo. It was found that while CE displayed a tendency to rise and then reduce during the transition from NAFL to NASH, ONOO- increased continuously, confirming that the combined imaging by CNFCl and DRNO might visualize the transformation of NAFL to NASH. The results provide robust visual tool to decipher the relationship between the stage of NAFLD and the level of CE/ONOO-. We anticipate this study may open new avenues to distinguish NASH from NAFL, which may further promote the study of intracellular biological activities of CE and the development of NAFLD diagnostic methods.

Betulinic acid mitigates zearalenone-induced liver injury by ERS/MAPK/Nrf2 signaling pathways in mice

Zearalenone (ZEA) is a mycotoxin commonly found in cereals and feedstuffs, which can induce oxidative stress and inflammation to cause liver damage in humans and animals. Betulinic acid (BA) is extracted from pentacyclic triterpenoids of many natural plants and has anti-inflammatory, and anti-oxidation biological activities in many studies. However, the protective effect of BA on liver injury induced by ZEA has not been reported. Therefore, this study aims to explore the protective effect of BA on ZEA-induced liver injury and its possible mechanism. In the mice experiment, ZEA exposure increased the liver index and caused histopathological impairment, oxidative damage, hepatic inflammatory responses, and increased hepatocyte apoptosis. However, when combined with BA, it could inhibit the production of ROS, up-regulate the proteins expression of Nrf2 and HO-1 and down-regulate the expression of Keap1, and alleviate oxidative damage and inflammation in the liver of mice. In addition, BA could alleviate ZEA-induced apoptosis and liver injury in mice by inhibiting the endoplasmic reticulum stress (ERS) and MAPK signaling pathways. In conclusion, this study revealed the protective effect of BA on the hepatotoxicity of ZEA for the first time, providing a new perspective for the development of ZEA antidote and the application of BA.

Overview of Cellular and Soluble Mediators in Systemic Inflammation Associated with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent chronic liver disease in Western countries, affecting approximately 25% of the adult population. This condition encompasses a spectrum of liver diseases characterized by abnormal accumulation of fat in liver tissue (non-alcoholic fatty liver, NAFL) that can progress to non-alcoholic steatohepatitis (NASH), characterized by the presence of liver inflammation and damage. The latter form often coexists with liver fibrosis which, in turn, may progress to a state of cirrhosis and, potentially, hepatocarcinoma, both irreversible processes that often lead to the patient's death and/or the need for liver transplantation. Along with the high associated economic burden, the high mortality rate among NAFLD patients raises interest, not only in the search for novel therapeutic approaches, but also in early diagnosis and prevention to reduce the incidence of NAFLD-related complications. In this line, an exhaustive characterization of the immune status of patients with NAFLD is mandatory. Herein, we attempted to gather and compare the current and relevant scientific evidence on this matter, mainly on human reports. We addressed the current knowledge related to circulating cellular and soluble mediators, particularly platelets, different leukocyte subsets and relevant inflammatory soluble mediators.

Multidimensional Biomarker Analysis Including Mitochondrial Stress Indicators for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is accompanied by a complex and multifactorial pathogenesis with sequential progressions from inflammation to fibrosis and then to cancer. This heterogeneity interferes with the development of precise diagnostic and prognostic strategies for NAFLD. The current approach for the diagnosis of simple steatosis, steatohepatitis, and cirrhosis mainly consists of ultrasonography, magnetic resonance imaging, elastography, and various serological analyses. However, individual dry and wet biomarkers have limitations demanding an integrative approach for the assessment of disease progression. Here, we review diagnostic strategies for simple steatosis, steatohepatitis and hepatic fibrosis, followed by potential biomarkers associated with fat accumulation and mitochondrial stress. For mitochondrial stress indicators, we focused on fibroblast growth factor 21 (FGF21), growth differentiation factor 15 (GDF15), angiopoietin-related growth factor and mitochondrial-derived peptides. Each biomarker may not strongly indicate the severity of steatosis or steatohepatitis. Instead, multidimensional analysis of different groups of biomarkers based on pathogenic mechanisms may provide decisive diagnostic/prognostic information to develop a therapeutic plan for patients with NAFLD. For this purpose, mitochondrial stress indicators, such as FGF21 or GDF15, could be an important component in the multiplexed and contextual interpretation of NAFLD. Further validation of the integrative evaluation of mitochondrial stress indicators combined with other biomarkers is needed in the diagnosis/prognosis of NAFLD.

Ancient wheats: beneficial effects on insulin resistance

Non-alcoholic fatty liver disease and type 2 diabetes mellitus are two conditions that commonly exist together in the context of the metabolic syndrome. Several scientific advances in understanding this association have identified insulin resistance as the key point in the pathogenesis of both diseases. The first line treatment suggested in the management of these diseases is represented by lifestyle changes and in particular the modification of alimentary regimen, with the transition to a healthy diet. In this context, several studies have focused their attention on the identification of food products with beneficial actions, like ancient wheat (AW). AW are defined as the early cereals that were domesticated in their places of origin in the "Fertile Crescent" of the Middle East, and played a central role as a main source of food for the early civilizations in that region. The present narrative review aims to provide a systematic overview of the state of the art on the effects of AW on insulin resistance.

Relationship between IL-8 Circulating Levels and TLR2 Hepatic Expression in Women with Morbid Obesity and Nonalcoholic Steatohepatitis

The progression of nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis (NASH) is linked to systemic inflammation. Currently, two of the aspects that need further investigation are diagnosis and treatment of NASH. In this sense, the aim of this study was to assess the relationship between circulating levels of cytokines, hepatic expression of toll-like receptors (TLRs), and degrees of NAFLD, and to investigate whether these levels could serve as noninvasive biomarkers of NASH. The present study assessed plasma levels of cytokines in 29 normal-weight women and 82 women with morbid obesity (MO) (subclassified: normal liver (n = 29), simple steatosis (n = 32), and NASH (n = 21)). We used enzyme-linked immunosorbent assays (ELISAs) to quantify cytokine and TLR4 levels and RTqPCR to assess TLRs hepatic expression. IL-1β, IL-8, IL-10, TNF-α, tPAI-1, and MCP-1 levels were increased, and adiponectin levels were decreased in women with MO. IL-8 was significantly higher in MO with NASH than in NL. To sum up, high levels of IL-8 were associated with the diagnosis of NASH in a cohort of women with morbid obesity. Moreover, a positive correlation between TLR2 hepatic expression and IL-8 circulating levels was found.

Porphyromonas gingivalis-derived lipopolysaccharide causes excessive hepatic lipid accumulation via activating NF-κB and JNK signaling pathways

BACKGROUND

Porphyromonas gingivalis is the main pathogen of periodontal disease affecting over half of the worldwide adult population. Recent studies have shown that P. gingivalis is related to the development of non-alcoholic fatty liver disease (NAFLD), a global major chronic liver disease, especially in developed countries. However, how P. gingivalis contributes to the pathogenesis of NAFLD has not been fully clarified. We aimed to conduct a preliminary exploration of the underlying mechanism of P. gingivalis infection in the development of NAFLD.

METHODS

Human hepatocellular cells HepG2 were incubated with/without oleic acid (OA) and tested for lipid accumulation upon stimulation by lipopolysaccharide (LPS) derived from P. gingivalis or Escherichia coli. Intracellular lipid droplet formation was analyzed and quantified by Oil Red O staining. The involvement of signaling pathway molecules and pro-inflammatory cytokines related to NF-κB and MAPKs were examined with Western blot and quantitative real-time PCR (qRT-PCR) analyses and further evaluated with inhibitor treatment and RNA interference.

RESULTS

HepG2 cells accumulated more intracellular lipids when stimulated with P. gingivalis LPS, as compared to cells treated with E. coli LPS or control. Further pathway analysis demonstrated that after stimulation with P. gingivalis LPS, cells displayed significantly upregulated MyD88 expression, increased phosphorylation of p65 and JNK, and more release of pro-inflammatory cytokines, such as IL-1, IL-8, and TNF-α. In addition, suppression of phosphorylation of p65 and JNK by inhibitors and RNA interference resulted in a reduction in lipid accumulation upon P. gingivalis LPS treatment.

CONCLUSIONS

These results suggest that P. gingivalis-derived LPS may contribute to intracellular lipid accumulation and inflammatory reaction of HepG2 cells via the activation of NF-κB and JNK signaling pathways. This study offers a possible explanation to the functional involvement of P. gingivalis infection in the pathological progression of NAFLD. These findings may help design new treatment strategies in NAFLD.

Insights into the Role and Interdependence of Oxidative Stress and Inflammation in Liver Diseases

The crucial roles of oxidative stress and inflammation in the development of hepatic diseases have been unraveled and emphasized for decades. From steatosis to fibrosis, cirrhosis and liver cancer, hepatic oxidative stress, and inflammation are sustained and participated in this pathological progressive process. Notably, increasing evidences showed that oxidative stress and inflammation are tightly related, which are regarded as essential partners that present simultaneously and interact with each other in various pathological conditions, creating a vicious cycle to aggravate the hepatic diseases. Clarifying the interaction of oxidative stress and inflammation is of great importance to provide new directions and targets for developing therapeutic intervention. Herein, this review is concerned with the regulation and interdependence of oxidative stress and inflammation in a variety of liver diseases. In addition to classical mediators and signaling, particular emphasis is placed upon immune suppression, a potential linkage of oxidative stress and inflammation, to provide new inspiration for the treatment of liver diseases. Furthermore, since antioxidation and anti-inflammation have been extensively attempted as the strategies for treatment of liver diseases, the application of herbal medicines and their derived compounds that protect liver from injury via regulating oxidative stress and inflammation collectively were reviewed and discussed.

Causes of Thickening of Carotid Intima-Media Thickness in Patients With Alcoholic Liver Disease: A Prospective Observational Study

Several studies have reported the relationship between alcoholic liver disease (ALD) and carotid intima-media thickness (CIMT). Few studies, however, have investigated the causes of CIMT thickening in patients with ALD. The authors explored the causes of CIMT thickening in patients with ALD. The authors enrolled 152 patients who were stratified into groups: nonthickening CIMT with ALD (group A); thickening CIMT with ALD (group B); nonthickening CIMT without ALD (group C); and thickening CIMT without ALD (group D). The CIMT was significantly different between patients with and without ALD (χ 2= 3.875, P = 0.049). The patients in groups A, B, and C were significantly younger than group D (P = 0.001, 0.036, and 0.001, respectively). The body mass indexes (BMI) in groups A and B were significantly higher than in group C (P = 0.000 and 0.007, respectively). The blood glucose levels in groups B and D were significantly higher than in group C (P = 0.016 and 0.018, respectively). The blood uric acid levels in group B were significantly higher than in groups A, C, and D (P = 0.009, 0.000, and 0.003, respectively). The blood uric acid in group A was significantly higher than in group C (P = 0.002). The serum total cholesterol (TC) levels of patients in group B were significantly higher than in groups A and C (P = 0.027 and 0.000, respectively) and the serum TC level in group A was significantly higher than in group C (P = 0.048). The serum triglyceride (TG) levels in groups A and B were significantly higher than in group C (P = 0.027 and 0.000, respectively). The serum of very low-density lipoprotein (VLDL) levels in group B were significantly higher than in group C (P = 0.000). Although a comparison of the low-density lipoprotein (LDL) and high-density lipoprotein (HDL) serum levels among the 4 groups indicated no changes. The serum LDL levels in group B were significantly higher than in group A (P = 0.008). No significant differences were observed among the groups with respect to serum homocysteine, C-reactive protein (CRP), interleukin-6 (IL-6), malondialdehyde (MDA), superoxide dismutase (SOD), soluble OX40 ligand (sOX40L), or heat shock protein (HSP) 60 or 70. Alcoholic liver disease may result in CIMT thickening. Carotid intima-media thickness is associated with age and metabolic factors in patients with ALD. In addition, ALD might promote the premature occurrence of CIMT thickening. The thickening of carotid artery intima thickness, however, is not associated with cytokine profiles, oxidative balance, or immune responses in patients with ALD.

Fibromyalgia symptoms and cirrhosis

BACKGROUND

An association between fibromyalgia and hepatitis C virus (HCV) has been previously described. However, the relationship between nonalcoholic steatohepatitis (NASH) and fibromyalgia symptoms has not been assessed, though they share several risk factors.

AIM

We aimed to assess the factors associated with fibromyalgia symptoms across etiologies of liver disease.

METHODS

Patients with cirrhosis due to HCV, NASH, or alcohol were recruited from an outpatient hepatology clinic and administered the Hospital Anxiety and Depression Score, Pittsburgh Sleep Quality Index, and the modified 2010 American College of Rheumatology Diagnostic Criteria for Fibromyalgia. Serum inflammatory markers were measured with standard luminex assays.

RESULTS

Of 193 participants, 53 (27 %) met criteria for fibromyalgia. Fibromyalgia symptoms were significantly associated with etiology of liver disease (HCV: 35 %, NASH: 30 %, alcohol-related liver disease: 12 %, p < 0.01). Using logistic regression, mood symptoms (OR 1.14, 95 % CI 1.06, 1.22), sleep disturbance (OR 1.32, 95 % CI 1.16, 1.52), and etiology of liver disease (NASH vs. HCV not different, alcohol vs. HCV OR 0.19, 95 % CI 0.05, 0.63) were associated with fibromyalgia symptoms. If abdominal pain was included in the model, etiology became nonsignificant, indicating that it may be central sensitization due to abdominal pain in patients with chronic liver disease that explains fibromyalgia symptoms rather than the etiology of liver disease or inflammation.

CONCLUSIONS

Fibromyalgia symptoms were significantly associated with HCV and NASH cirrhosis and with psychiatric symptoms. Future work should focus on the underlying pathophysiology and management of widespread pain in patients with cirrhosis.

The role of interleukin-6 and interleukin-8 gene polymorphisms in non-alcoholic steatohepatitis

BACKGROUND

Genetic polymorphisms may play role in the pathophysiology of nonalcoholic steatohepatitis (NASH).

OBJECTIVES

We purposed to assess the role of interleukin 6 (IL 6) and interleukin 8 (IL 8) gene polymorphisms in the pathogenesis of NASH.

PATIENTS AND METHODS

Consecutive patients with biopsy proven NASH and age- and gender-matched healthy individuals with normal liver function tests and normal ultrasonography were enrolled in the study. Histopathological findings were recorded according to nonalcoholic fatty liver disease activity score (NAS). Patients were classified according to fibrosis scores as fibrosis score < 2 (mild fibrosis group) and fibrosis score ≥ 2 (significant fibrosis group). Blood samples were collected and genomic DNA isolation kit was used to evaluate genetic polymorphisms.

RESULTS

Of thirty-eight patients, 27 (71%) were in mild fibrosis group and 11 (29%) in significant fibrosis group. Thirty-eight age- and gender-matched healthy controls were enrolled in the study. The frequencies of genotypes G/C and G/G of IL 6 among the NASH group and healthy controls were 39.5% and 60.5% vs. 53.6% and 46.4%, respectively (P = 0.32). The frequencies of the genotypes of IL 8 among the NASH group were 47.2%, 44.6%, and 8.2% for T/T, A/T, and A/A, and in healthy controls were 50%, 28.6% and 21.4%, respectively, (P = 0.568). The differences between IL 8 gene T/A and T/T genotypes were not significant statistically (P > 0.05). However, the frequency of A/A genotype in significant fibrosis group was higher than the mild fibrosis group (P = 0.0016). The differences of -251 A/T polymorphism in the IL 8 and -174 C/G polymorphism in the IL 6 were not statistically significant between fibrosis groups (P > 0.05).

CONCLUSIONS

IL6 and IL8 gene polymorphisms have no role in NASH pathogenesis and liver fibrosis process, but presence of the A/A genotype in the IL8 gene is associated with disease progression.

Nonalcoholic Fatty liver disease: pathogenesis and therapeutics from a mitochondria-centric perspective

Nonalcoholic fatty liver disease (NAFLD) describes a spectrum of disorders characterized by the accumulation of triglycerides within the liver. The global prevalence of NAFLD has been increasing as the obesity epidemic shows no sign of relenting. Mitochondria play a central role in hepatic lipid metabolism and also are affected by upstream signaling pathways involved in hepatic metabolism. This review will focus on the role of mitochondria in the pathophysiology of NAFLD and touch on some of the therapeutic approaches targeting mitochondria as well as metabolically important signaling pathways. Mitochondria are able to adapt to lipid accumulation in hepatocytes by increasing rates of beta-oxidation; however increased substrate delivery to the mitochondrial electron transport chain (ETC) leads to increased reactive oxygen species (ROS) production and eventually ETC dysfunction. Decreased ETC function combined with increased rates of fatty acid beta-oxidation leads to the accumulation of incomplete products of beta-oxidation, which combined with increased levels of ROS contribute to insulin resistance. Several related signaling pathways, nuclear receptors, and transcription factors also regulate hepatic lipid metabolism, many of which are redox sensitive and regulated by ROS.

Apoptotic and anti-apoptotic seromarkers for assessment of disease severity of non-alcoholic steatohepatitis

BACKGROUND AND STUDY AIMS

This study aimed to find out non-invasive markers for the assessment of severity of non-alcoholic steatohepatitis (NASH) in an attempt to decrease the need for liver biopsy. It also aimed to evaluate the key role of apoptosis in the pathogenesis of the disease and the suggested role of anti-apoptotic factors in therapeutic modalities and disease prognosis.

PATIENTS AND METHODS

The serum levels of soluble Fas (s. Fas), s. Fas ligand, cytokeratin 18 (CK-18) fragment and Bcl-2 were measured in 80 patients and 15 non-hepatic subjects as control. The patients were divided based on histological examination of liver biopsy into three groups. Group I included 40 patients with NASH, group II had 40 patients with non-alcoholic fatty liver disease (NAFLD) non-NASH and group III had 15 non-hepatic subjects as control. Apoptosis of hepatocytes was assessed by morphological examination using a light microscope and expressed as number per square millimetre.

RESULTS

There was a significant increase in the serum levels of s. Fas, s. Fas ligand and CK-18 fragments in the NASH group. The anti-apoptotic protein Bcl-2 showed significantly low levels in NASH patients. Apoptosis of hepatocytes was significantly higher in the NASH group. The degree of apoptosis was inversely correlated with the level of Bcl-2. A significant correlation between both s. Fas and CK-18 fragment with liver histology with regard to lobular inflammation and ballooning was found.

CONCLUSIONS

Increased serum levels of s. Fas and CK-18 fragment in the NASH group and its correlation with the severity of disease suggested the key role of apoptosis in NASH pathogenesis which can be used for the assessment of the severity of NASH. A high level of anti-apoptotic Bcl-2 in NAFLD suggests its protective role in disease progress.

Electron Therapy Attenuated Elevated Alanine Aminotransferase and Oxidative Stress Values in Type 2 Diabetes-Induced Nonalcoholic Steatohepatitis of Rats

Chronic oxidative stress plays a key role in the progression of nonalcoholic steatohepatitis (NASH). We examined the efficacy of antioxidative electron treatment on type 2 diabetes-induced NASH in a rat model. We established NASH model rats, induced by neonatal administration of streptozotocin and a high-fat diet, which exhibited pathologically high values of alanine aminotransferase (ALT), glucose, and malondialdehyde (MDA). The rats were exposed to electron discharge at very low energy for 4 weeks; this dose results in the reduction of Fe(3+) and glutathione disulfide in vitro. Serum ALT values were increased from baseline (8 weeks) to 125.0 ± 13 U/L at 10 weeks in the control group. In contrast, the values in the treated group did not show any increase at 10 weeks [87 ± 10 U/L (p = 0.0391)]. Hepatic MDA levels were also significantly decreased at 12 weeks (p < 0.05), but 8-hydroxy-2'-deoxyguanosine values were not statistically significant (p = 0.076). A gradual but steadily decreasing trend from initially high glucose levels was observed, though the values were not significant in 12-week-old animals (p = 0.074). However, the serum values of MDA, ALT, and glucose were well correlated. The progression of fibrosis as measured by increased serum levels of hyaluronic acid and histological examinations were not affected by the treatment in this model. Antioxidative electron treatment at very low energy attenuated the pathogenically elevated liver inflammation and oxidative stress, together with presumably impaired glucose metabolism in NASH rat model.

Role of cytokines and chemokines in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) includes a variety of histological conditions (ranging from liver steatosis and steatohepatitis, to fibrosis and hepatocarcinoma) that are characterized by an increased fat content within the liver. The accumulation/deposition of fat within the liver is essential for diagnosis of NAFLD and might be associated with alterations in the hepatic and systemic inflammatory state. Although it is still unclear if each histological entity represents a different disease or rather steps of the same disease, inflammatory processes in NAFLD might influence its pathophysiology and prognosis. In particular, non-alcoholic steatohepatitis (the most inflamed condition in NAFLDs, which more frequently evolves towards chronic and serious liver diseases) is characterized by a marked activation of inflammatory cells and the upregulation of several soluble inflammatory mediators. Among several mediators, cytokines and chemokines might play a pivotal active role in NAFLD and are considered as potential therapeutic targets. In this review, we will update evidence from both basic research and clinical studies on the potential role of cytokines and chemokines in the pathophysiology of NAFLD.

Serum Bcl-2 concentrations in overweight-obese subjects with nonalcoholic fatty liver disease

AIM: To shed some light on the relationship between anti-apoptotic serum Bcl-2 concentrations and metabolic status, anthropometric parameters, inflammation indices, and non-alcoholic fatty liver disease severity were investigated in 43 young individuals with fatty liver (FL) and 41 with nonalcoholic steatohepatitis (NASH).

METHODS: Circulating levels of Bcl-2 were detected in 84 patients with ultrasonographic findings of “bright liver” and/or hyper-transaminasemia of unknown origin and/or increase in γ-glutamyl-transpeptidase (γ-GT) strictly in the absence of other acute or chronic liver disease, whose age was not advanced, who gave consent to liver biopsy and were then divided on the basis of the histological results into two groups (43 with FL and 41 with NASH). Twenty lean subjects, apparently healthy and young, were chosen as controls.

RESULTS: Serum Bcl-2 concentrations were significantly higher in the FL group than in the NASH group. Insulin resistance and γ-GT activity were significantly higher in NASH subjects. Apoptotic hepatocytes were significantly more numerous in NASH patients. NASH patients presented with larger spleens and augmented C-reactive protein (CRP) concentrations than healthy subjects. Steatosis grade at histology was similar in both NASH and FL populations. The number of apoptotic cells was significantly related to anti-apoptotic Bcl-2 protein values in FL patients. Bcl-2 serum levels positively correlated to body mass index (BMI) values (P≤ 0.0001) but not to age of the population. Triglycerides/HDL ratio correlated well to waist circumference in males (P = 0.0008). γ-GT activity was associated with homeostatic metabolic assessment (HOMA) (P = 0.0003) and with serum ferritin (P = 0.02). Bcl-2 concentrations were not related to either spleen size or CRP values. NASH patients presented a weak negative correlation between lobular inflammation and Bcl-2 levels. A prediction by low values of serum Bcl-2 towards a greater presence of metabolically unhealthy overweight/obese patients (MUOs) was evidenced. HOMA, BMI and uric acid, in that sequence, best predicted serum Bcl-2 concentrations.

CONCLUSION: MUOs could be detected by Bcl-2 levels. By favoring the life span of hepatocytes, and enhancing triglyceride formation, the anti-apoptotic process inhibits free fatty acids toxicity in FL.

Circulating vaspin and its relationship with insulin sensitivity, adiponectin, and liver histology in subjects with non-alcoholic steatohepatitis

OBJECTIVE

Non-alcoholic steatohepatitis (NASH) is closely associated with components of metabolic syndrome. Vaspin is a novel adipocytokine that may link obesity, insulin resistance (IR), and type 2 diabetes mellitus. We aimed to investigate circulating vaspin levels in subjects with NASH and also to search for the association of vaspin with IR, adiponectin, and histological findings.

MATERIAL AND METHODS

A total of 50 male patients with NASH and 30 healthy male controls were enrolled. Vaspin and adiponectin were measured with ELISA method. Insulin sensitivity determined by homeostasis model assessment (HOMA-IR) index.

RESULTS

Plasma vaspin levels were higher and adiponectin levels were lower in NASH group compared with controls (p < 0.01 and p < 0.001, respectively). However, in multivariate analysis adjusted for glucose and lipid parameters, and HOMA-IR indexes, the difference in vaspin concentrations was disappeared. Nonetheless, the difference regarding the adiponectin levels remained significant between groups (p = 0.03). Vaspin was negatively correlated with low-density lipoprotein cholesterol (r = -0.32, p = 0.03) in subjects with NASH.

CONCLUSIONS

This study indicates that circulating vaspin levels are not altered in male subjects with NASH. These results suggest that in the absence of metabolic risk factors, vaspin per se may not be involved in the pathogenesis of NASH.

Type 2 Diabetes Mellitus-Induced Hyperglycemia in Patients with NAFLD and Normal LFTs: Relationship to Lipid Profile, Oxidative Stress and Pro-Inflammatory Cytokines

Type 2 diabetes mellitus is associated with dyslipdemia, insulin resistance and non alcoholic fatty liver disease. The purpose of the current study was to assess whether type 2 diabetes mellitus-induced hyperglycemia has an effect on the lipid profile and release of oxidative stress markers and inflammatory mediators in patients with non alcoholic fatty liver disease and normal liver function tests which may in turn lead to enhancing the pathogenicity of this liver disease. For this purpose, one hundred and five outpatients, matched in age and weight, were classified into two groups: the first group consisted of patients with non alcoholic fatty liver disease and the second group consisted of patients with non alcoholic fatty liver disease in conjunction with hyperglycemia due to the presence of type 2 diabetes mellitus. In all patients, lipid profile, oxidative stress, and inflammatory mediators were assessed by measuring serum concentrations of triglycerides, low density lipoprotein, hydrogen preroxide, malondialdehyde, tumor necrosis factor-alpha and interleukin-6, respectively. In the studied population, it was found that the presence of type 2 diabetes mellitus-induced hyperglycemia significantly impaired lipid profile, and significantly enhanced the formation of hydrogen preroxide and malondialdehyde as well as significantly increased the release of tumor necrosis factor-alpha and interleukin-6 in the second group of patients. In addition, plasma glucose level showed significant positive correlation with hydrogen peroxide, malondialdehyde, tumor necrosis factor-alpha and interleukin-6. From the previous results, it was concluded that the presence of type 2 diabetes mellitus-induced hyperglycemia results in significant increase in lipid profile, oxidative stress markers and inflammatory mediators in patients with non alcoholic fatty liver disease and normal liver function tests. For this reason, further research studies may be essential to evaluate the benefit of adding suitable antioxidant and anti-inflammatory drugs to the treatment regimen for this group of patients. In addition, regular monitoring of blood glucose levels and liver function tests should be advised to this category of patients to reduce liver fat deposition and avoid the development of non alcoholic steatohepatitis, cirrhosis or liver cancer and their related complications.

Small intestinal bacterial overgrowth in nonalcoholic steatohepatitis: association with toll-like receptor 4 expression and plasma levels of interleukin 8

BACKGROUND

Experimental and clinical studies suggest an association between small intestinal bacterial overgrowth (SIBO) and nonalcoholic steatohepatitis (NASH). Liver injury and fibrosis could be related to exposure to bacterial products of intestinal origin and, most notably, endotoxin, including lipopolysaccharide (LPS).

AIM

To compare the prevalence of SIBO and its relationships to LPS receptor levels and systemic cytokines in NASH patients and healthy control subjects.

METHODS

Eighteen NASH patients (eight males) and 16 age-matched and gender-matched healthy volunteers were studied. SIBO was assessed by the lactulose breath hydrogen test (LHBT), plasma lipopolysaccharide binding protein (LBP) levels by ELISA, and expression (as a percentage) of TLR-2 and 4 on CD14-positive cells by flow cytometry. Pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α) were measured in plasma.

RESULTS

SIBO was more common in NASH patients than control subjects (77.78% vs. 31.25%; P < 0.0001). LBP levels and TLR-2 expression were similar in both groups, TLR-4/MD-2 expression on CD14 positive cells was higher among NASH patients: expression, mean ± SEM, NASH vs. control: 20.95 ± 2.91% vs. 12.73 ± 2.29%, P < 0.05. Among the examined cytokines, only IL-8 levels were significantly higher in patients than control (P = 0.04) and correlated positively with TLR-4 expression (r = 0.5123, P = 0.036).

CONCLUSION

NASH patients have a higher prevalence of small intestinal bacterial overgrowth which is associated with enhanced expression of TLR-4 and release of IL-8. SIBO may have an important role in NASH through interactions with TLR-4 and induction of the pro-inflammatory cytokine, IL-8.

Selenium supplementation attenuates procollagen-1 and interleukin-8 production in fat-loaded human C3A hepatoblastoma cells treated with TGFbeta1

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with obesity, insulin resistance and hepatic steatosis. Non-alcoholic steatohepatitis (NASH) is a serious consequence of NAFLD where chronic tissue damage and inflammation result in fibrosis which may progress to cirrhosis. Transforming growth factor beta1 (TGFbeta1), proinflammatory cytokines and oxidative stress are thought to play crucial roles in the pathogenesis of these conditions. The contributions of individual liver cell types to fibrogenesis remain controversial and the influence of selenium status has not been investigated.

METHODS

In this study we have used a cell culture model of fat-loading using oleate-treated human hepatoblastoma (C3A) cells to investigate how fat-loading and selenium status might influence the production of collagen in response to TGFbeta1. The secretion of inflammatory cytokines was also investigated, together with the epithelial character of the treated cells.

RESULTS

We found that in response to treatment with TGFbeta1, C3A cells produced mRNA encoding the pro-alphaI chain of procollagen I, secreted procollagen I peptide, up-regulated production of the proinflammatory cytokine interleukin-8 (IL-8) and the mesenchymal marker vimentin, and down-regulated albumin production. Most of these responses were considerably enhanced when cells were fat-loaded with oleate and were attenuated by selenium addition at a dose that optimised the expression of thioredoxin reductase and glutathione peroxidase.

CONCLUSIONS

Our data establish that both fat-loading and suboptimal selenium status enhance collagen and IL-8 production by C3A hepatocytes in response to TGFbeta1, possibly as part of an epithelial to mesenchymal transition.

GENERAL SIGNIFICANCE

These findings suggest that the hepatocyte may be an important contributor to the pathogenesis of fibrosis associated with NAFLD.

Influence of inducible nitric oxide synthase polymorphisms in Japanese patients with non-alcoholic fatty liver disease

AIM

Genetic factors as well as environmental factors play an important role in the development of non-alcoholic fatty liver disease (NAFLD). Recently, inducible nitric oxide synthase (iNOS) was significantly higher in the severest form of non-alcoholic steatohepatitis (NASH), and nitric oxide (NO) has been determined to play an important role in the process of fibrosis in NASH. In this study, we investigated iNOS gene polymorphisms for associations with NAFLD.

METHODS

A total of 115 NAFLD patients, consisting of 65 patients with NASH and 50 patients with simple steatosis, in whom a positive diagnosis had been made by liver biopsy, and 435 healthy control subjects, were recruited into this study.

RESULTS

We investigated 10 single nucleotide polymorphisms (SNP) of the iNOS gene, one of which, rs1060822, had the lowest P-value in the allele frequency model (P = 0.00078) with an odds ratio (95% confidence interval) of 0.49 (0.32-0.75). Four SNP, rs2297510, rs2297511, rs2797512 and rs1060822, were significantly associated with NAFLD, even when the most conservative Bonferroni's correction was applied. Linkage disequilibrium analysis revealed that SNP rs1060822 and three other SNP, rs2297510, rs2297511 and rs2797512, were in the same block. We also investigated associations between rs1060822 genotypes and the fibrosis index, and the results of the analysis revealed an additive increase in the fibrosis index and intrahepatic iNOS mRNA expression in the patients with the T allele of rs1060822.

CONCLUSION

This is the first study to identify genetic variations in iNOS that may influence the risk of NAFLD and liver fibrosis in NAFLD.

Chitosan ameliorates the severity of steatohepatitis induced by high fat diet in rats

OBJECTIVE

Currently, no agent has been conclusively demonstrated to prevent the progression of non-alcoholic steatohepatitis (NASH). Chitosan, a natural product derived from chitin, was thought to possess hypocholesterolemic properties. The aim of this study was to evaluate the potential effects of chitosan on nutritional steatohepatitis in rats.

MATERIAL AND METHODS

Rats were fed with a high fat diet for 4 weeks to develop NASH that was confirmed by liver biopsy, and then 4 weeks of chitosan was given. Serum chemistry and liver histology were assessed and the steatoinflammatory mechanisms were studied.

RESULTS

Chitosan significantly protected against high fat diet-induced hepatic steatohepatitis. This effect was associated with repressed serum levels of total protein (TP), globulin (GLO), alanine aminotransferase (ALAT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), total cholesterol (TC) and low-density lipoprotein (LDL). Chitosan elevated the serum levels of high-density lipoprotein (HDL) and the ratio of albumin to globulin. Furthermore, increased TNF-alpha, lipoemia, hyperinsulinemia, hyperleptinemia and hypoadiponectin in NASH were significantly ameliorated by treatment with chitosan.

CONCLUSIONS

Chitosan effectively attenuated the steatohepatitis induced by a high fat diet. The therapeutic effect of chitosan on NASH may be activated through exerting an influence on adipokines.

Insulin resistance, inflammation, and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD), the major cause of abnormal liver function in the western world, is often associated with obesity and diabetes. In obese individuals, fat accumulation in the abdominal region affects both lipid and glucose metabolism, and a liver loaded with fat is insulin resistant. Insulin resistance (IR) is often associated with chronic low-grade inflammation, and numerous mediators released from immune cells and adipocytes contribute to development of IR. Recent results showing an important role for these mediators in NAFLD are providing us with a better understanding of this highly prevalent disease with implications for novel therapy development. This review highlights new aspects in development of liver steatosis and the relevance of various cytokines and adipocytokines in NAFLD.

Small intestinal bacteria overgrowth decreases small intestinal motility in the NASH rats

AIM: To explore the relationship between small intestinal motility and small intestinal bacteria overgrowth (SIBO) in Nonalcoholic steatohepatitis (NASH), and to investigate the effect of SIBO on the pathogenesis of NASH in rats. The effect of cidomycin in alleviating severity of NASH is also studied.

METHODS: Forty eight rats were randomly divided into NASH group (n = 16), cidomycin group (n = 16) and control group (n = 16). Then each group were subdivided into small intestinal motility group (n = 8), bacteria group (n = 8) respectively. A semi-solid colored marker was used for monitoring small intestinal transit. The proximal small intestine was harvested under sterile condition and processed for quantitation for aerobes (E. coli) and anaerobes (Lactobacilli). Liver pathologic score was calculated to qualify the severity of hepatitis. Serum ALT, AST levels were detected to evaluate the severity of hepatitis.

RESULTS: Small intestinal transit was inhibited in NASH group (P < 0.01). Rats treated with cidomycin had higher small intestine transit rate than rats in NASH group (P < 0.01). High fat diet resulted in quantitative alterations in the aerobes (E. coli) but not in the anoerobics (Lactobacill). There was an increase in the number of E. coli in the proximal small intestinal flora in NASH group than in control group (1.70 ± 0.12 log10 (CFU/g) vs 1.28 ± 0.07 log10 (CFU/g), P < 0.01). TNF-α concentration was significantly higher in NASH group than in control group (1.13 ± 0.15 mmol/L vs 0.57 ± 0.09 mmol/L, P < 0.01). TNF-αconcentration was lower in cidomycin group than in NASH group (0.63 ± 0.09 mmol/L vs 1.13 ± 0.15 mmol/L, P < 0.01). Treatment with cidomycin showed its effect by significantly lowering serum ALT, AST and TNF-α levels of NASH rats.

CONCLUSION: SIBO may decrease small intestinal movement in NASH rats. SIBO may be an important pathogenesis of Nash. And treatment with cidomycin by mouth can alleviate the severity of NASH.