非酒精性脂肪性肝病与代谢综合征的关系研究

目的:探讨非酒精性脂肪性肝病患病与代谢综合征的关系。方法:采用横断面调查研究方法,分析810例健康体检者的体重指数、血压、总胆固醇、甘油三酯、空腹血糖和肝脏超声检查相关临床资料。结果:非酒精性脂肪性肝病组中体重指数、血压、总胆固醇、甘油三酯和空腹血糖水平均明显高于对照组(P0.01);多因素Logistic回归分析结果显示,代谢综合征各组分中体重指数、甘油三酯、空腹血糖及舒张压升高是非酒精性脂肪性肝病发病的独立危险因子(P0.05)。结论:非酒精性脂肪性肝病患病与代谢综合征密切相关。     

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.     

Treatment of chronic periodontitis decreases serum prohepcidin levels in patients with chronic kidney disease

OBJECTIVE:

To determine the impact of periodontal treatment on serum levels of prohepcidin (the prohormone of hepcidin) and systemic inflammation markers, as well as correlations among these markers, in patients with chronic periodontitis and chronic kidney disease who were not undergoing dialysis.

METHODS:

We included 56 chronic periodontitis patients, 36 with chronic kidney disease and 20 without systemic diseases and with normal renal function (control group). Chronic kidney disease was defined as suggested by the clinical practice guidelines in the National Kidney Foundation. Chronic periodontitis was defined through clinical attachment level and by probing pocket depth, according to the American Association of Periodontology. The inflammatory markers ultrasensitive C-reactive protein, interleukin-6, and prohepcidin were evaluated before and 3 months after periodontal treatment.

RESULTS:

The efficacy of periodontal treatment was confirmed by the improvement in clinical parameters of chronic periodontitis in the control and chronic kidney disease groups. Periodontal treatment resulted in significant reductions in ultrasensitive C-reactive protein, interleukin-6 and serum prohepcidin levels in both groups. Moreover, in multivariate linear regression, the reduction in prohepcidin after periodontal treatment was significantly and independently associated with interleukin-6 levels in the control group.

CONCLUSIONS:

By inducing a decline in the systemic inflammatory response and a decrease in serum prohepcidin, successful periodontal treatment may represent an important means of ameliorating the inflammatory burden seen in patients with chronic kidney disease. Trial registration: ISRCTN59866656.     

Recent advances in nonalcoholic fatty liver disease metabolomics

The clinical phenotypes of nonalcoholic fatty liver disease (NAFLD) encompass from simple steatosis to nonalcoholic steatohepatitis (NASH) with varying degrees of fibrosis or cirrhosis. Liver biopsy has been the standard to diagnose NASH. However, there has been strong need for precise and accurate noninvasive tests because of invasiveness and sampling variability of biopsy. Metabolomics has drawn attention as a promising diagnostic methodology in the field of NAFLD, particularly to unravel metabolic alterations which plays relevant roles in the progression of NASH. There have been numerous metabolomics researches to find new biomarker of NASH in the last decade, fueled by the recent advances in the metabolomics methodology. This review briefly covers recent research advances on the lipidomics, amino acids and bile acid metabolomics regarding continuing attempts to discover relevant biomarkers for NASH.     

Evaluation and management of extrahepatic manifestations of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a multisystemic disease and a rapidly growing cause of chronic liver disease in children and adults worldwide. Diagnosis and management of extrahepatic manifestations of NAFLD, including cardiovascular disease (CVD), type 2 diabetes mellitus, metabolic syndrome, chronic kidney disease, obstructive sleep apnea, polycystic ovarian syndrome, hypothyroidism, psoriasis, and extrahepatic malignancy are crucial for the treatment of patients with NAFLD. The leading cause of death in NAFLD is primarily from CVD, followed by liver-related mortality, extrahepatic cancer, liver cancer, and diabetes-related mortality. Therefore, clinicians need to identify high-risk patients earlier in the disease course and be aware of the extrahepatic manifestations of NAFLD to improve liver disease outcomes. In this review, we focus on the monitoring and management of the extrahepatic manifestations of NAFLD.     

Serum levels of IL-10, IL-15 and soluble tumour necrosis factor-alpha (TNF-α) receptors in type C chronic liver disease

We previously reported that the number of TNF-α-producing cells was increased in the liver of patients with type C chronic liver disease. To understand further the pathophysiology of this change, we examined serum levels of two soluble TNF receptors, TNF-αRI (p55) and -αRII (p75), and IL-10, all of which act as TNF-α buffer, and IL-15, a novel cytokine sharing many immunological activities with IL-2, using ELISA methods. We studied control individuals and patients with type C chronic liver disease, including asymptomatic hepatitis C virus (HCV) carriers with persistently normal serum ALT values, and those with chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Both types of sTNF-αR closely correlated with disease progression. Patients with LC and HCC had significantly elevated levels for sTNF-αRII compared with the other patient groups and controls. Serum IL-10 levels were significantly greater in all chronic liver disease groups than in controls. With respect to IL-15, the values were high in CH, LC and HCC compared with those of controls. Notably, HCC patients showed highest values for both IL-10 and IL-15, with significant differences from the other patient groups. Serial determinations revealed that interferon (IFN) treatment for CH patients resulted in the suppression of circulating IL-10 and IL-15 levels along with decrease in serum aminotransferase values. Both cytokines remained at decreased levels after cessation of therapy in patients who went into clinical and virological remission. On the other hand, treatment did not affect serum levels of sTNF-αRs. These findings indicate that serum levels of these molecules correlated with disease progress in chronic HCV infection, and that IL-10 and IL-15 may reflect the degree of inflammation in the liver. It is also suggested that both cytokines may be related to the development of HCC.     

Toll-like receptor expression in chronic hepatitis C: Correlation with pro-inflammatory cytokine levels and liver injury

Background/Aims Toll-like receptors (TLR’s) are critical receptors that promote innate immune responses to pathogen-associated molecular patterns. Activation of TLR’s leads to production of pro-inflammatory cytokines such as tumour necrosis factor (TNF)-α. This study investigates whether peripheral blood monocyte expression of TLR’s is disturbed in patients with chronic hepatitis C and whether levels of expression of these molecules are significantly correlated with hepatitis C virus (HCV) genotype, viral load, hepatic necroinflammatory activity, histological stage and circulating TNF-α concentrations. Methods In 18 non-cirrhotic patients with biopsy-proven, virologically-confirmed chronic hepatitis C and 32 controls, we measured expression of TLR2 and TLR4 on peripheral blood monocytes. HCV genotype, viral load, serum alanine aminotransferase (ALT) levels, histological stage of disease and circulating TNF-α and endotoxin levels were also determined. Results Peripheral blood monocyte expression of TLR2 and TLR4 were significantly increased in patients with chronic hepatitis C compared to controls, irrespective of HCV genotype or histological stage of disease. Circulating levels of TNF-α were also significantly increased in patients with chronic hepatitis C. In both the overall study cohort and patients with chronic hepatitis C, monocyte expression of TLR2, but not of TLR4, correlated significantly with serum TNF-α levels. In patients with chronic hepatitis C, monocyte expression of TLR2, but not of TLR4, also correlated significantly with serum ALT levels. Expression of TLR’s was not significantly correlated with viral load. Conclusions Up-regulation of peripheral blood monocyte expression of TLR2 and TLR4 occurs in patients with chronic hepatitis C. Increased monocyte expression of TLR2, but not of TLR4, correlates significantly with both increased circulating TNF-α levels and hepatic necroinflammatory activity in this disorder. Received 24 August 2005; returned for revision 21 February 2006; accepted by G. Wallace 23 February 2006     

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.     

Intrahepatic expression of hepatitis C virus antigens in chronic liver disease

Localization of hepatitis C virus (HCV) antigens was studied in fresh frozen and formalin-fixed, paraffinembedded liver tissue by immunoperoxidase using monoclonal antibodies to nucleocapsid protein and polyclonal human immunoglobulin G purified from plasma containing antibodies to structural and non-structural antigens of hepatitis C virus. The results observed using monoclonal antibody to HCV core were similar to those of polyclonal IgG against HCV antigens in the majority of cases and both correlated well with HCV status as defined by ‘nested’ polymerase chain reaction. HCV antigens were detected in both hepatocytes and mononuclear cells. Using polyclonal human IgG, a small proportion of biliary epithelial cells were also positive in 6/29 patients. In most of the specimens examined, relatively few cells (1–5 per cent) were found to be positive for HCV antigens. The cryostat sections, using polyclonal IgG against HCV antigens, exhibited greater immunohistochemical staining, suggesting that the fixation and processing of the tissue may be a major factor in the conservation and the outcome of HCV antigen(s) findings. However, the results using monoclonal antibodies may reflect the specificity of antigen expression.     

Intestinal mucosal barrier dysfunction participates in the progress of nonalcoholic fatty liver disease

Intestinal mucosal barrier dysfunction is closely related to liver diseases, which implies impaired gut-liver axis may play a role in the pathogenesis of NAFLD. In our study, rats were divided into three groups: normal chow diet (NCD) group, high-fat diet (HFD) group and TNBS-induced colitis with high-fat diet (C-HFD) group. Liver tissues were obtained for histological observation and TNF-α, IL-6 mRNA determination and blood samples were collected for liver enzymes and LPS analysis. Ultrastructural changes of jejuna epithelium, SIBO and amounts of CD103⁺MHCII⁺DCs and CD4⁺CD25⁺FoxP3⁺T-regs in terms of percentage in mesenteric lymph nodes (MLN) were observed by electron microscope, bacterial cultivation and flow cytometry, respectively. The results demonstrated the pathological characteristics accorded with nonalcoholic simple fatty liver (NAFL) and NASH in HFD group by week 8 and 12, respectively. Besides, the degree of hepatic steatosis and steatohepatitis was more severe in C-HFD group compared with HFD-group at the same time point. NAFLD activity score (NAS), liver enzymes, concentration of LPS and mRNA expressions of TNF-α, IL-6 were higher significantly in C-HFD group compared with HFD and NCD group at week 4, 8 and 12, respectively. In HFD group, epithelium microvilli atrophy, disruptive tight junctions and SIBO were present, and these changes were more severe in NASH compared with NAFL. The percentage of CD103+MHCII+DCs and CD4+CD25+FoxP3+T-regs decreased significantly in NAFL and NASH compared with NCD group. Our conclusion was that gut-liver axis was impaired in NAFLD, which played crucial role in the pathogenesis of NAFLD.     

Hypoadiponectinemia and insulin resistance are associated with nonalcoholic fatty liver disease

We investigated the association between nonalcoholic fatty liver disease (NAFLD) and plasma adiponectin levels and insulin resistance. We recruited study subjects among one hundred and eighty one persons who were examined abdominal ultrasound at routine screening tests. A standard interview (consumption of alcohol and medical history), physical examination (height, weight, waist circumference, and blood pressure), and biochemical study (lipid parameters, aminotransferases, fasting plasma glucose, fasting insulin, and plasma adiponectin) were performed. Subjects who consumed alcohol more than moderate, evidence of viral hepatitis, toxic hepatitis, and serious cardiac, renal, or hepatic disease were excluded. Thirty-eight NAFLD patients and 53 control subjects diagnosed by ultrasound were finally analyzed. The plasma adiponectin level was significantly correlated with HDL-cholesterol (r=0. 38, p<0.001), triglycerides (r=-0.22, p=0.04), fasting insulin (r=-0.37, p<0.01), and insulin resistance by homeostasis model of assessment-insulin resistance (HOMAIR) (r=-0.39, p<0.01), after adjusting for age, sex, and adiposity. Multiple logistic regression analysis indicated that HOMA-IR was a significant predictor of having NAFLD (odds ratio [OR]=2.38; 95% confidence interval [CI]: 1.52-5.74), while adiponectin had a protective effect against NAFLD (OR=0.22; 95% CI: 0.09-0.55). We demonstrated that hypoadiponectinemia and insulin resistance are associated with NAFLD independent of obesity.     

糖尿病非酒精性脂肪肝病大鼠肝组织胰岛素受体、瘦素受体 mRNA的表达

目的：观察2型糖尿病大鼠肝脏的病理变化,探讨肝组织胰岛素受体（insulin R）、瘦素受体（leptin R）mRNA表达在糖尿病性非酒精性脂肪肝病（NAFLD）发病机制中的作用。方法：SD大鼠随机分成2组：正常组与2型糖尿病组。2型糖尿病组在以高脂饮食4周后,加小剂量(30 mg/kg)链脲佐菌素（STZ）诱导2型糖尿病性非酒精性脂肪性肝病大鼠模型,继续给予高脂饮食12周。分别采用HE染色、苏丹Ⅲ染色、Masson染色光镜下观察肝脏组织的病理改变;透射电镜观察肝脏超微结构改变;生化法检测血糖、血甘油三酯（TG）、血总胆固醇（TC）、丙氨酸转氨酶（ALT）和天门冬氨酸转氨酶（AST）水平;放免法检测血清胰岛素水平;ELISA法检测血清瘦素水平;RT-PCR法检测肝组织磷酸烯醇式丙酮酸羧激酶（PEPCK）、葡萄糖-6-磷酸酶（G6Pase）、insulin R、leptin R mRNA表达水平。结果：糖尿病大鼠肝细胞明显脂肪变性、碎片状坏死伴炎细胞浸润及肝纤维化病变,电镜下主要表现为肝细胞核固缩,胞浆内含大量脂滴,狄氏间隙胶原纤维增生;血糖、血胰岛素、TG、ALT、AST水平明显升高（P<0.01）,TC水平升高(P<0.05）,血清瘦素水平明显下降（P<0.01）;肝组织insulin R、leptin R mRNA表达显著升高（P<0.01）,PEPCK、G6Pase mRNA表达无显著变化。结论：2型糖尿病时的胰岛素抵抗是NAFLD发生的根源,由于胰岛素抵抗而致的低血清瘦素水平、肝组织insulin R、leptin R 表达上调参与了NAFLD的发生。     

HLA-E gene polymorphisms in chronic hepatitis C: Impact on HLA-E liver expression and disease severity

Hepatitis C virus usually produces chronic infection and liver damage. Considering that: i) the human leukocyte antigen-E (HLA-E) molecule may modulate the immune response, and ii) little is known about the role of HLA-E gene variability on chronic hepatitis C, we studied the impact of HLA-E polymorphisms on the magnitude of HLA-E liver expression and severity of hepatitis C. HLA-E variability was evaluated in terms of: i) single nucleotide polymorphism (SNP) alleles and genotypes along the gene (beginning of the promoter region, coding region and 3′UTR), and ii) ensemble of SNPs that defines the coding region alleles, considered individually or as genotypes. The comparisons of the HLA-E variation sites between patients and controls revealed no significant results. The HLA-E + 424 T > C (rs1059510), +756 G > A (rs1264457) and + 3777 G > A (rs1059655) variation sites and the HLA-E*01:01:01:01 and HLA-E*01:03:02:01 alleles, considered at single or double doses, were associated with the magnitude of HLA-E liver expression in Kupfer cell, steatosis, inflammatory activity and liver fibrosis. Although these associations were lost after corrections for multiple comparisons, these variable sites may propitiate biological clues for the understanding of the mechanisms associated with hepatitis C severity.