Min-Sun Kwak

Occult hepatitis B virus infection.

Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the hosts strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI.

Serum bilirubin levels are inversely associated with nonalcoholic fatty liver disease

Background/Aims Serum bilirubin exerts antioxidant and cytoprotective effects. In addition, elevated serum bilirubin levels are associated with a decreased risk of metabolic and cardiovascular diseases. However, few studies have evaluated whether serum bilirubin is associated with non-alcoholic fatty liver disease (NAFLD), which is closely associated with other metabolic diseases. The aim of this study was thus to elucidate the association between serum total bilirubin levels and NAFLD. Methods A cross-sectional study of 17,348 subjects undergoing a routine health check-up was conducted. Subjects positive for hepatitis B or hepatitis C virus, or with other hepatitis history were excluded. NAFLD was diagnosed on the basis of typical ultrasonographic findings and an alcohol consumption of less than 20 g/day. Results The mean age of the subjects was 49 years and 9,076 (52.3%) were men. The prevalence of NAFLD decreased steadily as the serum bilirubin level increased in both men and women (P<0.001 for both). Multivariate regression analysis adjusted for other metabolic risk factors showed that serum bilirubin level was inversely associated with the prevalence of NAFLD [odds ratio (OR)=0.88, 95% confidence interval (CI)=0.80-0.97]. Furthermore, there was an inverse, dose-dependent association between NAFLD and serum total bilirubin levels (OR=0.83, 95% CI=0.75-0.93 in the third quartile; OR=0.80, 95% CI=0.71-0.90 in the fourth quartile vs. lowest quartile, P for trend <0.001). Conclusions Serum bilirubin levels were found to be inversely associated with the prevalence of NAFLD independent of known metabolic risk factors. Serum bilirubin might be a protective marker for NAFLD.

Inhibition of hypoxia-inducible carbonic anhydrase-IX enhances hexokinase II inhibitor-induced hepatocellular carcinoma cell apoptosis

Aim:The hypoxic condition within large or infiltrative hypovascular tumors produces intracellular acidification, which could activate many signaling pathways and augment cancer cell growth and invasion. Carbonic anhydrase-IX (CA-IX) is an enzyme lowering pH. This study is to examine whether hypoxia induces CA-IX in hepatocellular carcinoma (HCC) cells, and to evaluate its clinical implication in HCC patients.Methods:Human HCC cell lines (Huh-7 and HepG2 cells) were used, and cell growth was assessed using MTS assay. CA-IX expression and apoptotic/kinase signaling were evaluated using immunoblotting. The cells were transfected with CA-IX-specific siRNA, or treated with its inhibitor 4-(2-aminoethyl) benzenesulfonamide (CAI#1), and/or the hexokinase II inhibitor, 3-bromopyruvate (3-BP). A clinic pathological analysis of 69 patients who underwent an HCC resection was performed using a tissue array.Results:Incubation of HCC cells under hypoxia (1% O2, 5% CO2, 94% N2) for 36 h significantly increased CA-IX expression level. CAI#1 (400 μmol/L) or CA-IX siRNA (100 μmol/L) did not influence HCC cell growth and induce apoptosis. However, CAI#1 or CA-IX siRNA at these concentrations enhanced the apoptosis induced by 3-BP (100 μmol/L). This enhancement was attributed to increased ER stress and JNK activation, as compared with 3-BP alone. Furthermore, a clinic pathological analysis of 69 HCC patients revealed that tumor CA-IX intensity was inversely related to E-cadherin intensity.Conclusion:Inhibition of hypoxia-induced CA-IX enhances hexokinase II inhibitor-induced HCC apoptosis. Furthermore, CA-IX expression profiles may have prognostic implications in HCC patients. Thus, the inhibition of CA-IX, in combination with a hexokinase II inhibitor, may be therapeutically useful in patients with HCCs that are aggressively growing in a hypoxic environment.

Cholecystectomy is independently associated with nonalcoholic fatty liver disease in an Asian population

AIM To investigate the relationship between gallstone disease and nonalcoholic fatty liver disease (NAFLD) in a large Asian population. METHODS A cross-sectional study including 17612 subjects recruited from general health check-ups at the Seoul National University Hospital, Healthcare System Gangnam Center between January 2010 and December 2010 was conducted. NAFLD and gallstone disease were diagnosed based on typical ultrasonographic findings. Subjects who were positive for hepatitis B or C, or who had a history of heavy alcohol consumption (> 30 g/d for men and > 20 g/d for women) or another type of hepatitis were excluded. Gallstone disease was defined as either the presence of gallstones or previous cholecystectomy, and these two entities (gallstones and cholecystectomy) were analyzed separately. Clinical parameters including body mass index, waist circumference, hypertension, diabetes, smoking status, and regular physical activity were reviewed. Laboratory parameters, including serum levels of gamma-glutamyl transpeptidase, alanine aminotransferase, aspartate aminotransferase, fasting glucose, fasting insulin, total cholesterol, triglycerides, and high-density lipoprotein, were also reviewed. RESULTS The mean age of the subjects was 48.5 ± 11.3 years, and 49.3% were male. Approximately 30.3% and 6.1% of the subjects had NAFLD and gallstone disease, respectively. The prevalence of gallstone disease (8.3% vs 5.1%, P < 0.001), including both the presence of gallstones (5.5% vs 3.4%, P < 0.001) and a history of cholecystectomy (2.8% vs 1.7%, P < 0.001), was significantly increased in the NAFLD group. In the same manner, the prevalence of NAFLD increased with the presence of gallstone disease (41.3% vs 29.6%, P < 0.001). Multivariate regression analysis showed that cholecystectomy was associated with NAFLD (OR = 1.35, 95%CI: 1.03-1.77, P = 0.028). However, gallstones were not associated with NAFLD (OR = 1.15, 95%CI: 0.95-1.39, P = 0.153). The independent association between cholecystectomy and NAFLD was still significant after additional adjustment for insulin resistance (OR = 1.45, 95%CI: 1.01-2.08, P = 0.045). CONCLUSION This study shows that cholecystectomy, but not gallstones, is independently associated with NAFLD after adjustment for metabolic risk factors. These data suggest that cholecystectomy may be an independent risk factor for NAFLD.

Role of physical activity in nonalcoholic fatty liver disease in terms of visceral obesity and insulin resistance

Limited evidence supports a role for physical activity (PA) in nonalcoholic fatty liver disease (NAFLD) independent of visceral obesity or/and insulin resistance. We investigated the association between PA and NAFLD while considering visceral adipose tissue (VAT) and insulin resistance in a large general population.

Polymorphisms near Interleukin 28B Gene Are Not Associated with Hepatitis B Virus Clearance, Hepatitis B e Antigen Clearance and Hepatocellular Carcinoma Occurrence

Background: Polymorphisms near the IL28B gene have been proposed to be strongly associated with treatment response and the rate of spontaneous clearance of hepatitis C virus infection, and treatment response of hepatitis B virus (HBV) infection. In this study, we aimed to determine whether these polymorphisms could affect natural courses of HBV infection. Methods: Genetic variations were identified through direct DNA sequencing using TaqMan assay in 1,439 patients with past or present HBV infection. Subjects included 404 spontaneously recovered patients, 313 chronic hepatitis B (CHB) patients, 305 liver cirrhosis (LC) patients and 417 hepatocellular carcinoma (HCC) patients. Three polymorphisms near the IL28B gene, rs8099917T>G, rs12979860C>T and rs12980275A>G, were identified. Associations between these polymorphisms and HBV clearance, hepatitis B e antigen (HBeAg) clearance as well as HCC occurrence among patients were analyzed using logistic regression analyses adjusted for age and gender. Results: There were no significant associations between these polymorphisms and the HBV clearance both in CHB and LC groups. Similarly, these polymorphisms showed no significant associations with HBeAg clearance and the occurrence of HCC either. Discussion: No significant association was identified between polymorphisms near the IL28B gene and the natural courses of chronic HBV infection, including the HBV clearance and HCC occurrence.

The serum vitamin D level is inversely correlated with nonalcoholic fatty liver disease

Background/Aims: A low vitamin D level has been associated with metabolic syndrome and diabetes. However, an association between a low vitamin D level and nonalcoholic fatty liver disease (NAFLD) has not yet been definitively established. This study aimed to characterize the relationship between a vitamin D level and NAFLD in Korea. Methods: A cross-sectional study involving 6,055 health check-up subjects was conducted. NAFLD was diagnosed on the basis of typical ultrasonographic findings and a history of alcohol consumption. Results: The subjects were aged 51.7±10.3 years (mean±SD) and 54.7% were female. NAFLD showed a significant inverse correlation with the vitamin D level after adjusting for age and sex [odds ratio (OR)=0.85, 95% confidence interval (CI)=0.75–0.96]. The age- and sex-adjusted prevalence of NAFLD decreased steadily with increasing vitamin D level [OR=0.74, 95% CI=0.60–0.90, lowest quintile (≤14.4 ng/mL) vs highest quintile (≥28.9 ng/mL), p for trend <0.001]. Multivariate regression analysis after adjusting for other metabolic factors revealed that NAFLD showed a significant inverse correlation with both the vitamin D level (>20 ng/mL) [OR=0.86, 95% CI=0.75-0.99] and the quintiles of the vitamin D level in a dose-dependent manner (p for trend=0.001). Conclusions: The serum level of vitamin D, even when within the normal range, was found to be inversely correlated with NAFLD in a dose-dependent manner. Vitamin D was found to be inversely correlated with NAFLD independent of known metabolic risk factors. These findings suggest that vitamin D exerts protective effects against NAFLD.

Hepatocellular Carcinoma: High Hepatitis B Viral Load and Mortality in Patients Treated with Transarterial Chemoembolization

PURPOSE To determine the relationship between hepatitis B virus (HBV) DNA level and the survival of patients with hepatocellular carcinoma treated by means of transarterial chemoembolization (TACE). MATERIALS AND METHODS This study was approved by the institutional review board, and the requirement to obtain informed consent was waived. From January 2005 to March 2007, 183 patients with HBV-related hepatocellular carcinoma who underwent TACE but never received antiviral therapy were consecutively enrolled in our cohort. All patients were tested for pre-TACE serum level of HBV DNA, and overall survival was measured from date of enrollment until death from any cause. Radiologic progression was evaluated by using the modified response evaluation criteria in solid tumors by means of independent radiologic assessment. RESULTS The median overall survival was 19 months (95% confidence interval: 13.7, 24.3) and median time to progression was 4 months (95% confidence interval: 3.03, 4.97). Multivariate analysis revealed that a high pre-TACE serum level of HBV DNA (> 2000 IU/L) was an independent risk factor for reduced overall survival (P = .021; hazard ratio [HR], 1.725), high cancer progression-related mortality (P = .014; HR, 1.936), and hepatic failure-related mortality associated with cancer progression (P = .005, HR, 3.908). Pre-TACE level of HBV DNA did not significantly affect hepatic failure-related mortality that was not caused by cancer progression. CONCLUSION A high pre-TACE serum level of HBV DNA was associated with poor overall survival and rapid progression of hepatocellular carcinoma after TACE, and the cause of mortality was not hepatitis exacerbation but cancer progression.

Association of Polymorphism in Pri-microRNAs-371-372-373 with the Occurrence of Hepatocellular Carcinoma in Hepatitis B Virus Infected Patients

Background Micro RNAs-371-372-373 (miRNAs-371-373), originating from the same pri-miRNA transcript, are reported to be upregulated in hepatocellular carcinoma (HCC) and to be related to the regulation of hepatitis B virus (HBV) infection. Our study investigated whether pri-miRNAs-371-373 polymorphisms are associated with the risk of HCC occurrence and HBV clearance. Methods Genetic variations were identified through direct DNA sequencing using TaqMan assay. Three sequence variants of pri-miRNAs-371-373 were identified. Genetic associations of those with HCC occurrence and HBV clearance among patients with HBV infection were analyzed using logistic regression analyses with adjustment for age and gender (n = 1439). Results For the occurrence of HCC, polymorphism rs3859501C>A acted as a protective factor both in chronic carriers (OR = 0.75, P = 0.005 in a codominant model; OR = 0.71, P = 0.02 in a dominant model; OR = 0.66, P = 0.03 in recessive model) and liver cirrhosis patients (OR = 0.69, P = 0.001 in a codominant model; OR = 0.60, P = 0.003 in a dominant model; OR = 0.63, P = 0.03 in a recessive model). The pri-miRNAs-371-373_ht2 [C-A-C] also showed a protective effect on HCC occurrence both in the chronic carrier and liver cirrhosis groups (P<0.05 in both). However, there was no significant association between pri-miRNAs-371-373 polymorphisms and HBV clearance. Conclusions In conclusion, among chronic carriers and liver cirrhosis patients, the A allele of rs3859501 and the haplotype pri-miRNAs-371-373_ht2 were more protective to HCC than other genotypes and haplotypes. Further studies into the roles of rs3859501 and pri-miRNAs-371-373_ht2 haplotype in hepatocarcinogenesis are needed.

Nonalcoholic Fatty Liver Disease Is Associated With Coronary Artery Calcification Development: A Longitudinal Study

CONTEXT Nonalcoholic fatty liver disease (NAFLD) is associated with coronary artery calcification (CAC) in cross-sectional studies. However, whether NAFLD itself affects CAC development or progression remains unknown. OBJECTIVE This study investigated the longitudinal association between NAFLD and CAC score. DESIGN AND SETTING This study is a longitudinal cohort study performed in a healthcare center. PARTICIPANTS Among 1732 subjects who underwent serial CAC evaluation, we evaluated 846 subjects with NAFLD and 886 subjects without NAFLD, as diagnosed via ultrasonography. MAIN OUTCOME MEASURES CAC score was compared at baseline and follow-up. In subjects without calcification (CAC score = 0) at baseline, any incidental calcification (CAC score >0) at follow-up was defined as development of CAC. In subjects with CAC (CAC score > 0) at baseline, confirmed CAC aggravation was defined as progression. Logistic regression analysis was performed. RESULTS More subjects with NAFLD than without showed CAC development or progression (48.8 vs 38.4%; P < .001). The impact of NAFLD on a change in CAC score significantly differed according to the CAC score at baseline. In subjects without calcification at baseline, NAFLD significantly affected the development of calcification (odds ratio, 1.49; 95% confidence interval, 1.01-2.21; P = .045) after adjusting for traditional metabolic risk factors. However, in subjects with baseline CAC, NAFLD did not significantly affect progression (P = .734). Additionally, the severity of NAFLD was important. The severity of NAFLD was dose-dependently associated with the development of CAC (P for trend = .043). CONCLUSIONS NAFLD plays a role in the early development of CAC, but not the progression. Ultrasonographic severity of NAFLD is dose-dependently associated with CAC development in subjects with a CAC score of 0 at baseline, independent of traditional risk factors.