Xingyong Wan

Effect of miR-34a in regulating steatosis by targeting PPARα expression in nonalcoholic fatty liver disease

MicroRNA-34a (miR-34a) is thought to be involved in nonalcoholic fatty liver disease (NAFLD). However, the association between altered expression of miR-34a and the pathophysiological features of NAFLD remains unclear. Here, we investigated the mechanisms by which miR-34a influences NAFLD through the PPARα-related pathway. Real-time quantitative PCR, western blotting and other assays kit were used to investigate the expression and function of miR-34a in an NAFLD model. Cultured cells transfected with miR-34a inhibitor and C57BL/6 mice injected with the miR-34a inhibitor through vein tail were conducted for the effects of miR-34a on its target. MiR-34a levels were significantly upregulated in steatosis-induced hepatocytes and in liver tissues of high-fat diet-fed mice. The upregulation of miR-34a resulted in the downregulation of hepatic PPARα and SIRT1 that are the direct targets of miR-34a. Silencing miR-34a led to an initially increased expression of PPARα, SIRT1 and PPARα’s downstream genes. Activation of the central metabolic sensor AMPK was also increased. The miR-34a inhibitor suppressed lipid accumulation and improved the degree of steatosis. Taken together, our data indicated that decreased expression of miR-34a potentially contributes to altered lipid metabolism in NAFLD. Downregulation of miR-34a may be a therapeutic strategy against NAFLD by regulating its target PPARα and SIRT1.

Xanthine oxidase in non-alcoholic fatty liver disease and hyperuricemia: One stone hits two birds

BACKGROUND & AIMS Hyperuricemia is a common feature of patients with non-alcoholic fatty liver disease (NAFLD). This study aimed to explore the causal relationship and underlying mechanisms between NAFLD and hyperuricemia. METHODS We evaluated the impact of NAFLD on the development of hyperuricemia in a cohort of 5541 baseline hyperuricemia-free individuals. We further analyzed xanthine oxidase (XO), a rate-limiting enzyme that catalyzes uric acid production, as a candidate to link NAFLD and hyperuricemia. RESULTS In the first study, a 7-year prospective analysis found that NAFLD was strongly associated with subsequent development of hyperuricemia. Cox proportional hazards regression analyses showed that age, gender, and body mass index adjusted hazard ratio (95% confidence interval) for incident hyperuricemia was 1.609 (1.129-2.294) in individuals with NAFLD, as compared with those without NAFLD at baseline. In the second study, we observed that expression and activity of XO were significantly increased in cellular and mouse models of NAFLD. Knocking down XO expression or inhibiting XO activity significantly decreases uric acid production and attenuates free fatty acids-induced fat accumulation in HepG2 cells. Inhibiting XO activity also significantly prevents the development of and ameliorates established hepatic steatosis induced by a high-fat diet in mice. Further experiments indicated that XO regulates activation of the NLRP3 inflammasome, which may be essential for the regulatory effect of XO on NAFLD. CONCLUSIONS NAFLD significantly increases the risk of incident hyperuricemia. XO is a mediator of the relationship between NAFLD and hyperuricemia, and may serve as a novel therapeutic target for the two linked diseases.

Prevalence of Helicobacter pylori Infection and its Relation with Body Mass Index in a Chinese Population

Helicobacter pylori infection is highly prevalent worldwide. The association between obesity and H. pylori infection is controversial in the literature. This study aims to investigate the prevalence of H. pylori infection and its relation with body mass index (BMI) in a Chinese population.

Probiotic supplementation does not improve eradication rate of Helicobacter pylori infection compared to placebo based on standard therapy: a meta-analysis

This meta-analysis included eligible randomized controlled trials (RCTs) with the aim of determining whether probiotic supplementation can improve H. pylori eradication rates. PUBMED, EBSCO, Web of Science, and Ovid databases were searched. We included RCTs that investigated the effect of combining probiotics, with or without a placebo, with standard therapy. A total of 21 RCTs that reported standard therapy plus probiotics were included. Compared to the placebo group, the probiotics group was 1.21(OR 1.21, 95% CI: 0.86, 1.69) and 1.28 (OR 1.28, 95% CI: 0.88, 1.86) times more likely to achieve eradication of H. pylori infection in intent-to-treat (ITT) analysis and per protocol (PP) analysis, respectively. Probiotics with triple therapy plus a 14-day course of treatment did not improve the eradication of H. pylori infection (OR 1.44, 95% CI: 0.87, 2.39) compared to the placebo. Moreover, the placebo plus standard therapy did not improve eradication rates compared to standard therapy alone (P = 0.816). However, probiotics did improve the adverse effects of diarrhea and nausea. These pooled data suggest that the use of probiotics plus standard therapy does not improve the eradication rate of H. pylori infection compared to the placebo.

Uric acid regulates hepatic steatosis and insulin resistance through the NLRP3 inflammasome-dependent mechanism

BACKGROUND & AIMS Hyperuricemia significantly increases risk of non-alcoholic fatty liver disease (NAFLD) and insulin resistance. However, the mechanisms responsible for this association are as yet unclear. This study aimed to investigate the effects and underlying mechanisms of uric acid on development of NAFLD and insulin resistance. METHODS We initially analyzed the impact of uric acid on the development of hepatic steatosis and insulin resistance in mice and in two cell models, HepG2 and L02. Subsequently, we studied the role of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in uric acid-induced fat accumulation and insulin signaling impairment. RESULTS We found that uric acid directly induces hepatocyte fat accumulation, insulin resistance, and insulin signaling impairment both in vivo and in vitro. We also found that uric acid-induced NLRP3 inflammasome activation, whereas lowering uric acid by allopurinol inhibited NLRP3 inflammasome activation in a high fat diet mouse model of NAFLD. Moreover, knocking down NLRP3 expression significantly attenuated uric acid-induced fat accumulation both in HepG2 cells and L02 cells. Knocking down NLRP3 expression also rescued uric acid-induced insulin signaling impairment in both cell types. CONCLUSIONS Uric acid regulates hepatic steatosis and insulin resistance through the NLRP3 inflammasome. Uric acid may be a new therapeutic target for NAFLD and insulin resistance.

A case–control study: Association between serum neuregulin 4 level and non-alcoholic fatty liver disease

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) is a great health burden. Neuregulin 4 (Nrg4) is a recently identified secret factor that may be associated with NAFLD. AIM To investigate the association between serum Nrg4 level and NAFLD by conducting a case-control study. METHOD A total of 174 subjects were included. 87 NAFLD subjects and 87 age- and sex-matched non-NAFLD controls were identified by hepatic ultrasound examination. Anthropometric and biochemical data were measured and recorded. Serum Nrg4 level was evaluated by using enzyme-linked immunosorbent assay. SPSS software was used for statistical analyses. RESULTS Compared to the controls, subjects with NAFLD presented with reduced level of serum Nrg4 (0.40 (0.27, 0.55) vs. 0.50 (0.30, 0.81)ng/mL (median (interquartile range)), P=0.029). By multivariate logistic regression analysis, reduced serum levels of Nrg4 were associated with higher NAFLD odds (OR=0.251, 95% confidence interval=0.081-0.779, P=0.017). By dividing the distribution of serum Nrg4 level into quartiles, there was borderline statistical difference of NAFLD prevalence among the four groups (P=0.058). There was no significant difference of serum Nrg4 levels in subjects according to the grades of fatty liver by ultrasound (P=0.080). No statistical difference of serum Nrg4 level was observed between obese and non-obese subjects (P=0.932). CONCLUSION Decreased serum Nrg4 level is prevalent in NAFLD subjects compared to non-NAFLD controls, and is an independent risk factor associated with NAFLD, indicating that Nrg4 might have a protective role in the development of NAFLD.

Role of NLRP3 Inflammasome in the Progression of NAFLD to NASH

Nonalcoholic fatty liver disease (NAFLD) has been recognized as a major public health problem worldwide. Nonalcoholic steatohepatitis (NASH) is an advanced form of NAFLD that may progress to cirrhosis and hepatocellular carcinoma. The pathogenesis of disease progression from NAFLD to NASH has not been fully understood. Immunological mechanisms that have been increasingly recognized in the disease progression include defects in innate immunity, adaptive immunity, Toll-like receptor (TLR) signaling, and gut-liver axis. The NLRP3 inflammasome is an intracellular multiprotein complex involved in the production of mature interleukin 1-beta (IL-1β) and induces metabolic inflammation. NLRP3 inflammasome has been recently demonstrated to play a crucial role in the progression of NASH. This review highlights the recent findings linking NLRP3 inflammasome to the progression of NASH.

Helicobacter pylori Induces Increased Expression of the Vitamin D Receptor in Immune Responses

Vitamin D receptor (VDR) is a member of the nuclear receptor family of transcription factors that play a critical role in innate immunity. This study examined the role of VDR in gastric innate immune defence against the gastric pathogen Helicobacter pylori.

Association between serum alpha-fetoprotein levels and fatty liver disease: A cross-sectional study

AIM To investigate the association between serum alpha-fetoprotein (AFP) levels and fatty liver disease (FLD) in a Chinese population. METHODS A cross-sectional study was performed among subjects who presented for a health examination at the First Affiliated Hospital, College of Medicine, Zhejiang University in 2013. FLD was diagnosed based on an ultrasonography examination. Serum AFP levels were measured with a chemiluminescence immunoassay. RESULTS Of the 9800 subjects enrolled, 2601 were diagnosed with FLD. Subjects with FLD had higher serum AFP levels than those without the disease. Subjects with high serum AFP levels had a higher prevalence of FLD, metabolic syndrome, and its components. Univariate logistic analysis showed that elevated serum AFP levels were associated with an increased risk of FLD (OR = 1.057, 95%CI: 1.031-1.084). However, after adjusting for covariates, AFP no longer remained significantly associated with the risk factors for FLD. CONCLUSION Our results suggest that serum AFP levels are significantly associated with FLD and that AFP acts as a cofactor, but not as an independent factor, for FLD.

Serum fetuin B level increased in subjects of nonalcoholic fatty liver disease: a case-control study

Abstract Fetuin is an endogenous inhibitor of the insulin receptor tyrosine kinase. Recent studies supported the possible role of fetuin B in metabolic diseases. This study is to evaluate the role of serum fetuin B in nonalcoholic fatty liver disease (NAFLD). A hospital-based case-control study of 184 subjects was conducted. Serum level of fetuin B was measured by enzyme-linked immunosorbent assay. The serum level of fetuin B in the control (91.0 ± 36.9 μg/ml) was lower than it in NAFLD (108.7 ± 38.5 μg/ml, P < 0.001). The percentage of NAFLD increased (42.9%, 58.7% and 60.2%; P < 0.001; linear-by-linear association: P < 0.001), as fetuin B concentration elevated in its tertiles, after adjustment of body mass index (BMI). Furthermore, compared with the 1st tertile, the 3rd tertile of fetuin B indicated an association with the presence of NAFLD (adjusted odds ratio = 2.087, 95% confidence interval [1.016 – 3.937], P = 0.023), after controlling age, sex, BMI, diabetes, hypertension and hypertriglyceridemia. Lastly, fetuin B correlated with diastolic blood pressure, serum alanine transaminase and triglycerides, among the controls. It suggested a potential association between serum fetuin B and the presence of NAFLD.