Adiponectin levels among patients with chronic hepatitis B and C infections and in response to IFN-alpha therapy

Roles of Adipokines in Digestive Diseases: Markers of Inflammation, Metabolic Alteration and Disease Progression

Adipose tissue is a highly dynamic endocrine tissue and constitutes a central node in the interorgan crosstalk network through adipokines, which cause pleiotropic effects, including the modulation of angiogenesis, metabolism, and inflammation. Specifically, digestive cancers grow anatomically near adipose tissue. During their interaction with cancer cells, adipocytes are reprogrammed into cancer-associated adipocytes and secrete adipokines to affect tumor cells. Moreover, the liver is the central metabolic hub. Adipose tissue and the liver cooperatively regulate whole-body energy homeostasis via adipokines. Obesity, the excessive accumulation of adipose tissue due to hyperplasia and hypertrophy, is currently considered a global epidemic and is related to low-grade systemic inflammation characterized by altered adipokine regulation. Obesity-related digestive diseases, including gastroesophageal reflux disease, Barrett's esophagus, esophageal cancer, colon polyps and cancer, non-alcoholic fatty liver disease, viral hepatitis-related diseases, cholelithiasis, gallbladder cancer, cholangiocarcinoma, pancreatic cancer, and diabetes, might cause specific alterations in adipokine profiles. These patterns and associated bases potentially contribute to the identification of prognostic biomarkers and therapeutic approaches for the associated digestive diseases. This review highlights important findings about altered adipokine profiles relevant to digestive diseases, including hepatic, pancreatic, gastrointestinal, and biliary tract diseases, with a perspective on clinical implications and mechanistic explorations.

Systematic review: chronic viral hepatitis and metabolic derangement

BACKGROUND

The liver has a critical role in the metabolism of glucose and lipids. Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection leads to a spectrum of liver disease including chronic hepatitis, cirrhosis and hepatocellular carcinoma. Metabolic syndrome (MetS) has a rising incidence owing to an epidemic of type 2 diabetes mellitus (T2DM) and obesity. Non-alcoholic fatty liver disease is a liver manifestation of MetS and has become the most common cause of chronic liver disease worldwide.

AIM

To summarise the interplay among hepatitis viruses, MetS and its components.

METHODS

We searched the literature about HBV, HCV infection, MetS, fatty liver and its components from PubMed.

RESULTS

With respect to the viral replication cycle, lipids are important mediators between viral entry and hepatocyte in HCV infection, but not in HBV infection. Thus, HCV infection is inversely associated with hyperlipidaemia and lipid rebound occurs following sustained viral response induced by interferon-based therapy or direct antiviral agents. In addition, HCV infection is positively associated with insulin resistance, hepatic steatosis, MetS and the risk of T2DM and atherosclerosis. In contrast, HBV infection may protect infected subjects from the development of MetS and hepatic steatosis. Accumulating evidence suggests that HBV infection is inversely associated with lipid metabolism, and exhibits no conclusive association with insulin resistance or the risk of T2DM and arteriosclerosis.

CONCLUSIONS

In patients with viral hepatitis and concurrent metabolic diseases, a multidisciplinary approach should be given rather than simply antiviral treatment.

The evolving relationship between adiponectin and insulin sensitivity in hepatitis C patients during viral clearance

BACKGROUND

The evolution of the relationship between adiponectin and insulin sensitivity in hepatitis C virus (HCV) patients during viral clearance is unclear and warrants investigation.

METHODS

A prospective study including 747 consecutive chronic hepatitis C (CHC) patients, of whom 546 had completed a course of anti-HCV therapy and underwent pre-, peri- and post-therapy surveys for anthropomorphic, viral, metabolic and hepatic profiles and adiponectin levels, was conducted in a tertiary care center.

RESULTS

Multivariate analyses indicated associations of sex, triglyceride levels and hepatic steatosis with adiponectin levels and of triglyceride levels and interferon λ3 (IFNL3) genotype with homeostasis model assessment-estimated insulin resistance (HOMA-IR) levels before anti-HCV therapy. In patients with a sustained virological response (SVR; n = 455), at 24 weeks post-therapy, sex, BMI, aspartate aminotransferase to platelet ratio index (APRI), HOMA-IR and steatosis were associated with adiponectin levels, and IFNL3 genotype was associated with HOMA-IR levels. GEE analysis demonstrated that SVR affected longitudinal trends in adiponectin levels. Compared with pre-therapy levels, adiponectin and APRI levels decreased 24 weeks post-therapy in SVR patients, regardless of baseline insulin resistance (IR). However, HOMA-IR levels decreased in SVR patients with baseline IR but increased in those without baseline IR. Compared with controls, immunohistochemical studies showed that pre-therapy CHC patients had higher hepatic adiponectin expression associated with hepatic fibrosis.

CONCLUSIONS

During HCV infection, adiponectin may affect insulin sensitivity through triglycerides. After viral clearance, adiponectin levels were directly associated with insulin sensitivity and decreased upon improved hepatic fibrosis; with a link to the IFNL3 genotype, insulin sensitivity improved only in patients with baseline IR.

Plasma adipokines and risk of hepatocellular carcinoma in chronic hepatitis B virus-infected carriers: a prospective study in taiwan

BACKGROUND

Obesity is considered a risk factor for hepatocellular carcinoma (HCC). The relationship between adipocytokine and HCC in hepatitis B virus (HBV) carriers remains unclear. We prospectively investigated the association of adiponectin, leptin, and visfatin levels with HCC.

METHODS

We conducted a nested case-control study in a community-based cohort with 187 incident HCC and 374 HCC-free HBV carriers. Unconditional logistic regression was conducted to estimate the ORs and 95% confidence intervals (CI).

RESULTS

Adiponectin, but not leptin and visfatin, levels were associated with an increased risk of HCC after adjustment for other metabolic factors and HBV-related factors. The risk was increased [OR = 0.51; 95% CI, 0.12-2.11; OR = 4.88 (1.46-16.3); OR = 3.79 (1.10-13.0); OR = 4.13 (1.13-15.1) with each additional quintiles, respectively] with a significant dose-response trend (P(trend) = 0.003). HCC risk associated with higher adiponectin level was higher in HBV carriers with ultrasonographic fatty liver, genotype C infection, higher viral load, and with elevated alanine aminotransferase. Longitudinally, participants with higher adiponectin were less likely to achieve surface antigen of hepatitis B virus (HBsAg) seroclearance and more likely to have persistently higher HBV DNA. Eventually, they were more likely to develop liver cirrhosis [OR = 1.65 (0.62-4.39); OR = 3.85 (1.47-10.1); OR = 2.56 (0.96-6.84); OR = 3.76 (1.33-10.7) for the second, third, fourth, and fifth quintiles, respectively; P(trend) = 0.017] before HCC.

CONCLUSIONS

Elevated adiponectin levels were independently associated with an increased risk of HCC.

IMPACT

Adiponectin may play different roles in the virus-induced and metabolic-related liver diseases, but the underlying mechanism remains unknown.

Association between hepatitis B virus infection and metabolic syndrome: a retrospective cohort study in Shanghai, China

Background

Metabolic syndrome (MS) and hepatitis B (HBV) infection are two major public health problems in China. There are few studies about their association, and the results of these studies are contradictory. We conducted a retrospective cohort study to assess the association between MS and HBV in a Shanghai community-based cohort.

Methods

Nine hundred seventy-six Shanghai residents were recruited from the Putuo community. 480 HBV infections were in exposed group and 496 non-infections in unexposed group. All metabolic-related parameters and hepatitis B serology were tested with routine biochemical or immunological methods. “Exposed” was defined by HBV infection represented by hepatitis B surface antigen (HBsAg) and without anti-virus treatment. “Unexposed” were subjects who didn’t infect with HBV (Represented by HBsAg) and no MS when they entered the cohort. MS was defined based on the updated National Cholesterol Education Program Adult Treatment Panel III criteria. The Cox proportional hazards model was used to estimate the hazard ratios (HR) and related 95% confidence intervals (95% CI) for the association between HBV infection and MS over a 20-year follow-up period.

Results

Of 976 subjects recruited, 480 had latent HBV infection (exposed subjects). After adjusting for age, the crude HR was 2.46 (95% CI: 1.77, 3.41). After adjusting for potential risk factors of MS (age, gender, smoking, passive smoking, alcohol consumption, physical activity, and diet), the HR was 2.27 (95% CI: 1.52, 3.38).

Conclusions

This 20-year follow-up retrospective cohort study in Shanghai showed a positive association between HBV infection and MS.

Serum adiponectin levels are associated with hepatitis B viral load in overweight to obese hepatitis B virus carriers

OBJECTIVE

This study aimed to investigate the association between serum adiponectin and chronic hepatitis B virus (HBV) infection.

DESIGN AND METHODS

We conducted a campus-based cross-sectional study in Northern Taiwan, an HBV-endemic country. A total of 506 participants, including 147 chronic HBV-infected individuals and 359 healthy controls, were assessed for anthropometric indices, serum adiponectin levels, serum HBV viral load and markers, serum alanine aminotransferase levels and metabolic factors.

RESULTS

Older age, male gender, higher alanine aminotransferase, higher body mass index, greater waist circumference, lower fasting glucose, higher triglycerides, and higher adiponectin were associated with chronic HBV infection in univariate analyses. In multivariate analysis, the presence of chronic HBV infection was positively associated with serum adiponectin levels (P < 0.0001) and high adiponectin levels over the 75th percentile (odds ratio, 4.25; 95% confidence interval, 2.36-7.66; P < 0.0001) after adjusting for age, gender, body mass index, and insulin resistance index. Furthermore, serum adiponectin levels were positively associated with HBV viral load in overweight to obese HBV-infected subjects (P = 0.018).

CONCLUSION

Although chronic HBV-infected individuals were heavier than healthy controls, they had significantly higher serum adiponectin levels than healthy counterparts. Additionally, adiponectin levels were positively associated with HBV viral load in overweight to obese HBV-infected subjects. Future research should focus on elucidating adiponectin pathways, which may contribute to the development of adjuvant treatments for chronic HBV infection.

Impact of hepatitis B virus infection on metabolic profiles and modifying factors

The metabolic syndrome may cause disease progression in patients with chronic hepatitis B (CHB). However, the interactions between hepatitis B virus (HBV) infection and metabolic factors remain unknown. We investigated the association of HBV infection with metabolic profiles in HBV-infected and noninfected subjects. In addition, the impacts of serum HBV DNA level on metabolic profiles were studied. Initially, a case-control analysis of patients with and without chronic HBV infection was performed. The HBV group consisted of 322 patients with chronic HBV infection, and the control group consisted of 870 matched subjects without HBV infection. Fasting blood glucose, lipid profiles and adiponectin levels were compared. The results were then confirmed in a second retrospective cohort study in 122 CHB patients with serum HBV DNA levels and HOMA-IR index values. In the case-control analysis, the HBV group had significantly higher serum adiponectin, but lower triglyceride (TG) and high-density lipoprotein cholesterol (HDL) levels than the control group. These relationships already existed in subjects younger than 45 years of age and were modified by serum alanine aminotransferase (ALT) levels. In the retrospective cohort, serum HBV DNA levels were negatively proportional to TG levels, but not to other metabolic parameters. Moreover, this relationship was significant only in subjects with higher ALT levels. Compared with healthy adults, patients with chronic HBV infection have significantly higher serum adiponectin, but lower TG and HDL levels. These relationships are modified by ALT levels and already exist in middle-age patients with chronic HBV infection, implying HBV may interact with host metabolism.

HOMA-AD in Assessing Insulin Resistance in Lean Noncirrhotic HCV Outpatients

Introduction. There is an association between HCV and insulin resistance (IR), which is currently assessed by HOMA-IR. There is evidence that HOMA-adiponectin (HOMA-AD) is more accurate, but its role in HCV patients is unknown. The purpose of this study was to evaluate IR in an HCV sample and controls, in order to compare the accuracy of HOMA-IR and HOMA-AD. Methods. Ninety-four HCV outpatients aged <60 years who met the criteria of nondiabetic, nonobese, noncirrhotic, and nonalcohol abusers were included and compared to 29 controls. Fasting glucose, insulin, adiponectin, and lipid profiles were determined. IR was estimated by HOMA-IR and HOMA-AD. Results. The groups were similar regarding sex and BMI, but the HCV patients were older. The median insulin level was higher in the HCV group (8.6 mU/mL (6.5-13.7) versus 6.5 (4.3-10.7), P = 0.004), as was median HOMA-IR (1.94 (1.51 to 3.48) versus 1.40 (1.02 to 2.36), P = 0.002) and the prevalence of IR (38.3% versus 10.3% (P = 0.009)). No differences were found in adiponectin levels (P = 0.294) and HOMA-AD (P = 0.393). Conclusion. IR is highly prevalent even in low-risk HCV outpatients. Adiponectin is not influenced by the presence of HCV. HOMA-AD does not seem to be useful in assessing IR in HCV patients.

Adiponectin, a downstream target gene of peroxisome proliferator-activated receptor γ, controls hepatitis B virus replication

In this study, HepG2-hepatitis B virus (HBV)-stable cells that did not overexpress HBx and HBx-deficient mutant-transfected cells were analyzed for their expression of HBV-induced, upregulated adipogenic and lipogenic genes. The mRNAs of CCAAT enhancer binding protein α (C/EBPα), peroxisome proliferator-activated receptor γ (PPARγ), adiponectin, liver X receptor α (LXRα), sterol regulatory element binding protein 1c (SREBP1c), and fatty acid synthase (FAS) were expressed at higher levels in HepG2-HBV and lamivudine-treated stable cells and HBx-deficient mutant-transfected cells than in the HepG2 cells. Lamivudine treatment reduced the mRNA levels of PPARγ and C/EBPα. Conversely, HBV replication was upregulated by adiponectin and PPARγ agonist rosiglitazone treatments and was downregulated by adiponectin siRNAs. Collectively, our results demonstrate that HBV replication and/or protein expression, even in the absence of HBx, upregulated adipogenic or lipogenic genes, and that the control of adiponectin might prove useful as a therapeutic modality for the treatment of chronic hepatitis B.

Adipocytokine involvement in hepatocellular carcinoma after sustained response to interferon for chronic hepatitis C

AIM

  Interferon (IFN) dramatically reduces the risk of hepatocellular carcinoma (HCC) after a sustained virological response (SVR) to chronic hepatitis C (CH-C). However, HCC still develops in some patients after SVR. To evaluate metabolic factors in patients with HCC occurring after SVR and to determine whether insulin resistance and adipocytokines were involved in this etiology.

METHODS

  We examined clinical and biochemical features, histological findings and serum levels of adipocytokine prior to IFN therapy and at the detection of HCC in nine patients who were diagnosed with HCC. As controls, 27 patients were included who showed SVR but had not been diagnosed with HCC for at least 5 years after SVR.

RESULTS

  Three of four patients who developed HCC within 5 years after SVR showed liver cirrhosis when HCC was diagnosed. Prior to IFN therapy, four of nine HCC patients were diagnosed as having type 2 diabetes mellitus. Serum levels of leptin and insulin, Homeostatic Model of Assessment of Insulin Resistance and body mass index (BMI) were significantly higher and serum adiponectin was significantly lower in HCC patients at the time of HCC detection than in control patients more than 5 years after SVR. Six HCC patients had increased BMI and one HCC patient had a decreased BMI during the observation period.

CONCLUSION

  Hepatic fibrosis may be tightly related to the emergence of HCC after SVR. Insulin resistance and adipocytokine disorders may be implicated in hepatocarcinogenesis after SVR, in part by promoting hepatic fibrosis.

Adipokines in liver diseases

Adipokines are polypeptides secreted in the adipose tissue in a regulated manner. While some of these molecules are expressed only by adipocytes, resident and infiltrating macrophages and components of the vascular stroma markedly contribute to expression of other adipokines. As a result, adipose tissue inflammation is associated with a modification in the pattern of adipokine secretion. Leptin, adiponectin, and resistin are the best-studied molecules in this class, but cytokines such as tumor necrosis factor or interleukin-6 are also secreted at high levels by the adipose tissue. Several other molecules have been recently identified and are actively investigated. Adipokines interfere with hepatic injury associated with fatty infiltration, differentially modulating steatosis, inflammation, and fibrosis. Several studies have investigated plasma levels of adiponectin in patients with nonalcoholic fatty liver disease, to establish correlations with the underlying state of insulin resistance and with the type and severity of hepatic damage. Hepatitis C is another disease where adipokines may represent a link between viral infection, steatosis, and metabolic disturbances. Identification of the mediators secreted by expanded adipose tissue and their pathogenic role is pivotal in consideration of the alarming increase in the prevalence of obesity and of the detrimental role that this condition exerts on the course of liver diseases.

Association of inflammatory and anti-inflammatory cytokines with insulin resistance in chronic hepatitis C

BACKGROUND

The pathogenetic basis for the association between hepatitis C virus (HCV) infection and type-2 diabetes remains uncertain. It has been reported that insulin resistance (IR) plays an essential role. We investigated the association of inflammatory [tumour necrosis factor (TNF)-alpha, interleukin (IL)-6] and anti-inflammatory cytokines (adiponectin and IL-10) with IR in chronic HCV infection.

METHODS

Eighty-one consecutive non-diabetic chronic hepatitis C patients (37 men and 44 women, mean age of 51.9+/-12.2 years) and 40 age, sex and body mass index (BMI)-matched healthy individuals were collected. IR was evaluated by the homoeostasis model assessment (HOMA). Serum levels of cytokines were measured by enzyme-linked immunosorbent assay.

RESULTS

Patients with chronic hepatitis C have a higher HOMA-IR, TNF-alpha, IL-6, adiponectin and IL-10, as compared with controls. By multiple linear regression analysis, moderate/severe steatosis grade, total cholesterol level and adiponectin was significantly associated with HOMA-IR, whereas, TNF-alpha, IL-6 and IL-10 was not. Male gender, BMI and HOMA-IR was inversely correlated with the serum adiponectin level. Serum adiponectin was positively correlated with TNF-alpha level, which was significantly associated with higher degree of hepatic necroinflammation.

CONCLUSION

Our data suggest that chronic HCV infection is associated with increased IR, which is correlated inversely with the serum adiponectin level. The complex role of adiponectin in the pathogenesis of IR and hepatic necroinflammation in chronic HCV infection merit further investigation.

High serum adiponectin correlates with advanced liver disease in patients with chronic hepatitis B virus infection

PURPOSE

Adiponectin possesses anti-inflammatory and insulin-sensitizing properties. Little is known about the role of adiponectin in hepatitis B-related liver disease.

METHODS

Serum adiponectin and hepatitis B viral factors were cross-sectionally assayed in 280 patients with chronic hepatitis B virus (HBV) infection including 120 patients with chronic HBV infection, 40 patients with cirrhosis, and 120 patients with hepatocellular carcinoma (HCC); 116 healthy adults were used as controls. The dynamics of serum adiponectin level was also studied longitudinally in 25 patients with hepatitis B e antigen (HBeAg) seroconversion (SC).

RESULTS

We found that serum adiponectin level in patients with chronic HBV infection was similar to that in healthy controls and was significantly lower than patients with cirrhosis and HCC. In univariate analysis, high serum adiponectin level significantly correlated with the presence of HBV-related cirrhosis or HCC, abnormal serum ALT level, and HBV genotype C. Multivariate analysis revealed that high serum adiponectin level significantly correlated with the development of HCC. Serum adiponectin levels remained stationary in patients experiencing HBeAg SC.

CONCLUSIONS

Our findings suggest that HBV infection itself does not affect adiponectin levels. Serum adiponectin level correlates with the progression of HBV-related liver diseases but not with the development of HBeAg SC.

Serum level of adiponectin correlated with gender and genotype in patients with chronic hepatitis C

Adiponectin is well recognized as plasma physiologically active polypeptide hormone exclusively derived from human and animal mature adipocytes, with vigorous property in antidiabetic, antiobesity, antiatherogenic, and anti-inflammatory processes. In this study, we investigated the correlation between serum adiponectin level and clinical and pathological parameters in patients with chronic hepatitis C (CHC). The study included 127 patients with CHC and 42 healthy volunteers as controls whose laboratory parameters and serum adiponectin and tumor necrosis factor-alpha (TNF-alpha) were assessed using enzyme-linked immunosorbent assay (ELISA). We demonstrated that a lower serum adiponectin level was associated with male gender, higher gamma-glutamyltransferase (gamma-GGT), higher albumin, higher TNF-alpha, and steatosis grade. The higher level of serum adiponectin in patients with genotype 2a was demonstrated when compared with that in the patients with genotype 1b. Furthermore, of great interest, results suggested that the significant differences regarding viral genotype seemed to occur only in male patients with CHC but not in female patients. In conclusion, serum adiponectin was associated with gender, genotype, liver steatosis, and TNF-alpha in a Chinese population with CHC.

Hepatitis C virus infection enhances insulin resistance induced by visceral fat accumulation

BACKGROUND/AIMS

To clarify the impact of visceral obesity on hepatitis C virus (HCV)-infected patients, we examined the relationship between insulin resistance development and visceral fat accumulation.

METHODS

We analyzed 87 HCV-infected patients with mild fibrosis (stage 1 or 2) in comparison with 125 sex- and age-matched patients with non-alcoholic fatty liver disease (NAFLD). The degree of visceral fat area (VFA; cm(2)) at the umbilical level was measured by abdominal computed tomography and divided into two grades: no visceral obesity, VFA<100 and visceral obesity, VFA>/=100. Insulin resistance was evaluated by homeostasis model assessment of insulin resistance (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI). Pancreatic beta-cell function was evaluated by homeostasis model assessment of beta-cell function (HOMA-beta). Serum soluble tumour necrosis factor (TNF)-receptors 1 and 2 and adiponectin were measured.

RESULTS

Insulin resistance evaluated by HOMA-IR and QUICKI was correlated with visceral fat accumulation, and was higher in HCV patients than in NAFLD patients with visceral obesity. HOMA-beta was higher in HCV patients than in NAFLD patients for each VFA grade. Serum-soluble TNF-receptors 1 and 2 were higher in HCV patients than in NAFLD patients with visceral obesity.

CONCLUSIONS

Hepatitis C virus infection is a risk factor for development of insulin resistance, particularly in patients with visceral obesity.

Adiponectin: a new independent predictor of liver steatosis and response to IFN-alpha treatment in chronic hepatitis C

OBJECTIVES

To compare serum adiponectin and tumor necrosis factor (TNF)-alpha among patients with viral liver diseases; to investigate associations of serum adiponectin and TNF-alpha with histological or viral characteristics of chronic hepatitis C (CHC); to investigate adiponectin and TNF-alpha alterations during interferon (IFN)-alpha treatment; and to assess the relationship between serum adiponectin and TNF-alpha and response rates to treatment.

METHODS

Adiponectin (mug/mL) and TNF-alpha (pg/mL) determinations by enzyme-linked immunosorbent assay (ELISA) in serial samples (before, the middle, the end, and 6 months after the end of treatment) from 83 CHC and 59 chronic hepatitis B (CHB) patients. Forty-three blood donors served as healthy controls. Patients were treated with IFN-alpha (4.5 MU/t.i.w.) for 12 months in CHB cases, and IFN-alpha (3 MU/t.i.w.) plus ribavirin for 6-12 months according to hepatitis C virus (HCV) genotype in CHC cases.

RESULTS

After adjustment for gender and body mass index (BMI), HCV genotype 3 overweight patients (BMI > 25 kg/m(2)) had significantly lower adiponectin (7.3 +/- 2.7) at baseline compared with non-3 HCV genotype overweight patients (P < 0.05). Lower adiponectin (HCV genotype 3, P= 0.02 and HCV genotype 1, P= 0.025) and higher TNF-alpha (P= 0.025) at baseline were identified as independent predictors of liver steatosis in CHC patients. Lower adiponectin was also identified as an independent predictor of no virological response at the end of treatment (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.66-0.87, P < 0.001). At the end of IFN-alpha therapy, only HCV genotype 3 patients had significantly higher serum adiponectin (10.4 +/- 6.3) compared with its levels before treatment (8.7 +/- 4.7, P < 0.05).

CONCLUSIONS

This study suggests that HCV genotype 3 may directly affect adiponectin. This is further supported by the significant increase in adiponectin at the end of treatment only in HCV genotype 3 patients. Serum adiponectin at baseline appears to be an independent predictor of liver steatosis and for the achievement of end-of-treatment virological response, while serum TNF-alpha at baseline was identified as an independent predictor only of liver steatosis.

High hepatitis C viral load is associated with insulin resistance in patients with chronic hepatitis C

BACKGROUND AND AIMS

Although insulin resistance affects liver fibrosis progression and treatment response in chronic hepatitis C (CHC), the relationship between chronic hepatitis C virus (HCV) infection and insulin resistance (IR) remains to be firmly established. We thus studied the impact of host, metabolic and viral factors on IR in CHC patients.

METHODS

A total of 162 CHC patients with complete clinical data were enrolled. Among them, 94 received histological examinations. Quantitative HCV RNA was assayed by a real-time polymerase chain reaction (PCR) assay. Genotyping was performed by reverse transcription PCR with type-specific primers. The pretreatment IR index was determined using homeostasis model assessment (HOMA), and an index value of more than 2.4 was designated IR. Unadjusted and adjusted association of the HCV RNA level and IR was further analysed.

RESULTS

In multivariate linear regression analysis, a dose-response relationship was observed between the log(10) HCV RNA level and the presence of IR. IR was positively correlated with body mass index, triglyceride, HCV RNA and alanine aminotransferase levels, but negatively correlated with adiponectin level. Subgroup analysis stratified by HCV genotype showed that there was a trend towards a higher HOMR-IR index value and lower adiponectin levels in genotype 1 patients. Histological analysis showed that IR was positively associated with the severity of hepatic steatosis.

CONCLUSIONS

Our data indicate that higher HCV RNA levels are associated with the presence of IR in CHC patients. Further studies are needed to clarify the interplays between HCV infection, IR and adiponectin in an attempt to develop new adjuvant therapy for CHC.

Correlation of serum adiponectin levels and hepatic steatosis in hepatitis C virus genotype 1 infection

Steatosis is an important cofactor in hepatitis C virus (HCV) because it is associated with fibrosis and reduces early and sustained virologic response. Recent studies suggest that HCV genotype 1 is not steatogenic if additional risk factors are not present. Because hypoadiponectinemia was found to be a feature of nonalcoholic steatohepatitis (NASH) independent of insulin resistance, its level in patients with hepatitis C genotype can reveal the optimal therapeutic strategy. This study was conducted to determine the role of the relationship between steatosis and serum adiponectin levels in the progression of liver damage in HCV genotype 1 without known risk factors for NASH. Patients (n=50) with biopsy-proven chronic hepatitis C (CHC), positive HCV RNA, and raised alanine aminotransferase were enrolled. They were carefully selected to rule out possible confounding factors for the presence of steatosis and additional systemic or liver disease. Associations between serum adiponectin levels and grade of steatosis, histologic activity index (HAI), fibrosis grade of liver biopsies, patient age, HCV viral load, and serum transaminase activities were studied. Also, adiponectin levels were compared with those of a control group of 30 healthy volunteers with normal ultrasound findings of the upper abdomen who had no known NASH risk factors. The investigators found that adiponectin levels in patients with CHC genotype 1 were similar to those in healthy subjects. No significant association was found between adiponectin levels and severity of steatosis, HCV RNA levels, HAI, transaminases, and fibrosis. Steatosis was present in 41 patients (82%) with CHC. Multivariate analysis of data on 50 patients revealed that severity of steatosis was independently related to age alone (P=.03). A correlation between HCV RNA load and HAI was observed (P=.02; r=0.712). HAI also was associated with stage of fibrosis (P=.00; r= 0.612). In cases of chronic HCV genotype 1 hepatitis, steatosis is a common histologic feature, although no risk factors are known. Results presented here cannot establish an association between adiponectin and severity of steatosis when risk factors for steatosis are unknown. Additional studies are needed to discover a metabolic treatment that would seek to improve the progression of hepatic steatosis in CHC infection.

The effect of infliximab on circulating levels of leptin, adiponectin and resistin in patients with inflammatory bowel disease

BACKGROUND

Tumour necrosis factor alpha is a critical mediator of inflammation-related altered metabolism in inflammatory bowel disease (IBD), possibly through its interaction with adipokines, which play an important role in IBD. Infliximab is a well established antitumour necrosis factor alpha treatment in IBD.

AIM AND METHODS

We studied serum levels of leptin, adiponectin and resistin in 20 IBD patients before and after infliximab treatment using commercially available enzyme-linked immunosorbent assays. The results were correlated with alterations of disease activity, BMI and C-reactive protein.

RESULTS

Infliximab induced clinical response or remission in 18 out of 20 treated IBD patients. Mean serum-leptin levels were 4.6+/-0.5 and 5.1+/-0.5 ng/ml (P=0.41), mean serum-adiponectin levels were 10513.9+/-1216.9 and 9653.5+/-1031.5 ng/ml (P=0.36) and mean serum-resistin levels were 26.3+/-4.1 and 13.9+/-1.4 ng/ml (P=0.004), before and after infliximab treatment, respectively. No significant correlation between the changes of BMI, C-reactive protein or the clinical indices of activity and alterations of the examined adipokines was found.

CONCLUSIONS

Serum levels of leptin and adiponectin had no significant alterations, whereas serum-resistin levels are significantly decreased after infliximab therapy in IBD patients, suggesting a possible proinflammatory status for resistin in IBD and a role as a marker of successful therapy.

Glucose intolerance and hypoadiponectinemia are already present in lean patients with chronic hepatitis C infected with genotype non-3 viruses

OBJECTIVES

Steatosis and metabolic abnormalities seem to be frequent and deleterious in chronic hepatitis C. Changes in glucose homeostasis and in adiponectin levels, an adipokine with anti-inflammatory and insulin-sensitive properties, were evaluated in patients with chronic hepatitis C according to steatosis, liver fibrosis and body mass index.

METHODS

Seventy-three patients with chronic hepatitis C (40 men, 33 women) infected with genotypes non-3 and 22 healthy controls (11 men and 11 women) were included in the study and all had a biochemical evaluation, including metabolic parameters, adiponectin measurement, and a liver biopsy. Insulin sensitivity was assessed with the HOMA 1-IR insulin resistance model.

RESULTS

Steatosis was found in 65.7% of the patients and significant fibrosis (METAVIR F2-F4) was present in 28.7%. The presence of steatosis could only be predicted by fibrosis, whereas significant fibrosis could be predicted by steatosis and age. Adiponectin levels were significantly decreased (-32%) with the severity of the steatosis. Although overweight chronic hepatitis C patients (body mass index>or=25 kg/m2) had insulin resistance and hypoadiponectinemia, lean chronic hepatitis C patients (body mass index<25 kg/m2) had already significantly higher glycemia and lower adiponectin levels than in controls.

CONCLUSIONS

This study confirms the high incidence of steatosis in patients infected by hepatitis C virus genotypes non-3, well linked to the development of fibrosis and metabolic abnormalities. Importantly, the present findings put emphasis on the early development of these metabolic abnormalities as they were already found in lean patients with chronic hepatitis C. The direct implication of hepatitis C virus is thus further stressed in the development of steatosis and insulin resistance, with or without involvement of host factors.

Insulin resistance and liver injury in hepatitis C is not associated with virus-specific changes in adipocytokines

The role of tumor necrosis factor alpha, interleukin 6, leptin, and adiponectin in the pathogenesis of hepatitis C virus (HCV)-associated insulin resistance (IR) remains controversial. We tested the hypothesis that these adipocytokines contribute to chronic HCV-associated IR and liver injury by first comparing their serum levels and homeostasis model assessment of insulin resistance (HOMA-IR) in 154 untreated, non-diabetic, HCV-infected male subjects with fibrosis stage 0-2, to that in 75 healthy volunteers matched for age, body mass index (BMI), and waist-hip ratio (WHR). We next examined whether the adipocytokine levels were associated with the extent of hepatic steatosis, portal/periportal inflammation and fibrosis in our total cohort of 240 HCV-infected male subjects. Significantly higher levels of HOMA-IR (2.12 versus 1.63, P = 0.01), TNFalpha (1.28 versus 0.60 pg/ml, P < 0.001) and IL6 (2.42 versus 1.15 pg/ml, P = 0.001) were noted in the HCV cohort compared with healthy controls respectively, but there were no significant differences in leptin and adiponectin concentrations. By multiple linear regression, independent predictors of HOMA-IR included the body mass index, and the serum levels of leptin (positive correlation) and adiponectin (negative correlation), but not that of TNFalpha and IL6. Only TNFalpha levels were correlated with the extent of histological injury (portal/periportal inflammation, P = 0.02).

CONCLUSION

Whereas leptin and adiponectin contribute to IR, none of the adipocytokines accounted for the elevated IR in HCV-infected subjects. The adipocytokines were not associated with histological features of chronic HCV infection except for TNFalpha which correlated with portal/periportal inflammation. HCV-associated IR is most likely an adipocytokine-independent effect of the virus to modulate insulin sensitivity.

The impact of insulin resistance, serum adipocytokines and visceral obesity on steatosis and fibrosis in patients with chronic hepatitis C

AIMS

To assess whether host metabolic factors influence the degree of hepatic steatosis and fibrosis in patients infected with hepatitis C virus, and to evaluate the impact of anti-viral therapy on insulin resistance and serum levels of adipocytokines.

METHODS

Clinical and biochemical features, anthropometrical characteristics, and levels of fasting insulin, leptin, adiponectin and resistin were measured in 'naïve' patients with chronic hepatitis C, before, during and after therapy with Peg-Interferon-alpha 2a plus Ribavirin.

RESULTS

Forty-eight patients were included (M/F 28/20; mean age 50.0 +/- 12.6 years; 62.5% genotype-1). Body mass index was 26.4 +/- 4.0 kg/m(2), and visceral obesity was present in 24 patients. At multivariate analysis (RR; 95% CI), steatosis was associated to older age (1.08; 1-1.18), necroinflammatory activity (17.67; 1.6-194.46), and raised insulin levels (1.39; 1.1-1.77). Fibrosis was related to necroinflammatory activity (25.73; 2.54-261.11), and steatosis (6.47; 1.09-38.29). Sustained viral response was achieved by 62.5% of patients and was associated with younger age (0.92; 0.85-0.99), genotype non-1 (10.61; 1.52-73.76) and absence of visceral obesity (13.78; 2.36-80.29). At the end of follow-up, insulin and the homeostasis model assessment for insulin resistance were reduced and adiponectin increased when compared with baseline, all unrelated to the outcome of treatment.

CONCLUSIONS

Visceral obesity correlates with the degree of steatosis and fibrosis, and it negatively affects treatment response. Significant changes of insulin resistance and adipocytokines occur under treatment, irrespective of virological outcome.

Circulating levels of leptin, adiponectin, resistin, and ghrelin in inflammatory bowel disease

BACKGROUND

There is evidence that adipocytokines play an important role in metabolism and in inflammation. Because human metabolism dramatically changes in inflammatory bowel disease (IBD) and chronic inflammation is the hallmark of the disease, we studied serum levels of leptin, adiponectin, resistin, and ghrelin in patients with ulcerative colitis (UC) and Crohn's disease (CD) in comparison with healthy controls (HC).

METHODS

Leptin, adiponectin, resistin, and active ghrelin serum levels were measured in 100 IBD patients (46 UC and 54 CD) and in 60 matched HC using commercially available enzyme-linked immunosorbent assays. Leptin, adiponectin, resistin, and ghrelin levels were correlated with disease activity, type, localization, and treatment.

RESULTS

Mean serum leptin levels were 10.6+/-2.0 ng/mL in UC patients, 12.5+/-2.6 ng/mL in CD patients, and 15.0+/-1.8 ng/mL in HC (P=.01). Mean serum adiponectin levels were 9514.8+/-787.8 ng/mL in UC patients, 7651.1+/-613 ng/mL in CD patients, and 7270.6+/-559.4 ng/mL in HC (P=.05). Mean serum resistin levels were 21.2+/-2.2 ng/mL in UC patients, 18.7+/-1.6 ng/mL in CD patients and 11.8+/-0.6 ng/mL in HC (P=.0002). Mean serum ghrelin levels were 48.2+/-4.2 pg/mL in UC patients, 49.4+/-4.6 pg/mL in CD patients and 14.8+/-3.0 pg/mL in HC (P<.0001). Serum levels of these adipocytokines were not correlated with either C-reactive protein levels or the clinical indices of activity. No association between serum adipocytokines levels and disease localization in both UC and CD patients was found. Only serum ghrelin was significantly higher in ileal compared with colonic CD (P=.04).

CONCLUSIONS

Serum levels of adiponectin, resistin, and active ghrelin are increased whereas serum levels of leptin are decreased in patients with IBD. Further studies are needed to elucidate the role of adipocytokines in IBD.