Serum retinol binding protein 4 and nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus

Retinol binding protein 4 (RBP4) is a protein secreted by adipocytes, and closely associated with insulin resistance. Whereas RBP4 is also mainly expressed in hepatocytes as the principal transport protein for retinol (vitamin A) in the circulation, and its pathophysiological role in liver remain unclear. The aim of this paper was to investigate the association between RBP4 and nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM). Serum RBP4 and adiponectin concentrations were measured by radioimmunoassay in 52 diabetic patients who had NAFLD and 50 sex- and age-matched diabetic patients without any clinical features of liver diseases who had normal liver ultrasonic appearance and normal liver function. Serum RBP4 levels were elevated in diabetic patients with NAFLD (32.0+/-8.9 microg/ml vs. 41.3+/-9.8 microg/ml, p<0.001), while adiponectin decreased (17.4+/-9.3 microg/ml vs. 13.8+/-7.0 microg/ml, p=0.032). Male diabetic patients had higher serum RBP4 concentration and lower serum adiponectin concentration than female diabetic patients (38.5+/-9.9 microg/ml vs. 34.0+/-10.7 microg/ml, p=0.031 and 12.7+/-5.7 microg/ml vs. 20.23+/-9.8 microg/ml, p<0.001, respectively). Multiple logistic regression analysis revealed RBP4 and triglyceride as independent association factors for NAFLD, while the association between serum adiponectin and NAFLD was not significant. Increasing concentrations of RBP4 were independently and significantly associated with NAFLD in diabetic patients. In multiple linear regression analysis, alanine aminotransferase, fasting serum insulin and adiponectin were independent factors for serum RBP4 level. The study demonstrates that retinol binding protein 4 might contribute to the pathogenesis of nonalcoholic fatty liver disease.     

Serum FGF21 and RBP4 levels in patients with chronic hepatitis C

Abstract Introduction. Fibroblast growth factor-21 (FGF21) regulates glucose, lipid, and energy homeostasis. Retinol-binding protein-4 (RBP4) controls metabolic and proliferative cell functions. Aims and methods. Aims of the study were to assess (1) serum FGF21 and RBP4 levels in 75 non-obese chronic hepatitis C (CHC) patients and 41 healthy controls similar in age and BMI; (2) the relationship between their serum concentration and insulin resistance, liver histology, and biochemical parameters; (3) their effectiveness as diagnostic markers. Results. FGF21 levels increased significantly in CHC patients compared with controls (p = 0.04). CHC patients with steatosis had significantly higher FGF21 levels compared with those without steatosis (p = 0.01). FGF21 concentration was positively related to steatosis grade (r = 0.39, p = 0.007). RBP4 levels did not differ between CHC patients and controls, but were negatively associated with necro-inflammatory activity grade (r = (-0.34), p = 0.04), with significantly higher levels in patients with minimal inflammatory activity (G1 vs. G2/3, p < 0.001; G1 vs. G2, p = 0 < 001; G1 vs. G3, p = 0.01). After stepwise linear regression analysis adjusting for potential confounders, RBP4 levels retained their independent significance as a predictor of necro-inflammatory activity (β = -0.31; t = -2.15, p = 0.035) and FGF21 levels as a predictor of steatosis (β = 0.34; t = 2.31, p = 0.024). Serum FGF21 correlated with serum RBP4 levels (r = 0.32, p = 0.02). Conclusions. Serum FGF21 levels increased in CHC patients, especially in those with steatosis and were associated with steatosis grade. FGF21 seems to be a useful diagnostic marker in determining hepatic steatosis in CHC. A negative association between serum RBP4 and necro-inflammatory activity indicates that disease severity may determine RBP4 levels.     

Prevalence and clinical associations of posttransplant fatty liver disease.

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease (NAFLD) could recur after liver transplant in patients with preexisting NAFLD, and has recently been reported to occur after transplant in patients transplanted without preexisting NAFLD. The literature on posttransplant NAFLD is limited. We aimed to study the prevalence of posttransplant NAFLD in patients transplanted for non-NAFLD-related liver diseases. METHODS: Thirty liver transplant recipients: 18 with chronic hepatitis B (CHB), seven with chronic hepatitis C (CHC), five others, were recruited. Liver biopsies were performed in all CHB and CHC patients annually as per protocol, or when clinically indicated. All biopsies were reviewed by one hepato-histopathologist blindly to assess and stage for steatosis and steatohepatitis. RESULTS: After a mean follow-up of 44+/-4 months, 12 (40%) and four (13%) developed posttransplant steatosis and steatohepatitis, respectively. None developed steatosis-related fibrosis or cirrhosis. Posttransplant steatohepatitis was associated with higher pretransplant body mass index (BMI) (32.3+/-3.9 vs 23.1+/-0.8, P=0.02) and higher BMI at last biopsy (32.5+/-4.3 vs 22.9+/-0.7, P=0.01). CONCLUSION: Posttransplant steatosis is common after liver transplant even in patients transplanted for non-NAFLD-related liver diseases. However, it is mostly benign during our follow-up, with only 13% developing steatohepatitis and none with fibrosis or cirrhosis.     

Serum FGF21 and RBP4 levels in patients with chronic hepatitis C

Abstract

Introduction. Fibroblast growth factor-21 (FGF21) regulates glucose, lipid, and energy homeostasis. Retinol-binding protein-4 (RBP4) controls metabolic and proliferative cell functions. Aims and methods. Aims of the study were to assess (1) serum FGF21 and RBP4 levels in 75 non-obese chronic hepatitis C (CHC) patients and 41 healthy controls similar in age and BMI; (2) the relationship between their serum concentration and insulin resistance, liver histology, and biochemical parameters; (3) their effectiveness as diagnostic markers. Results. FGF21 levels increased significantly in CHC patients compared with controls (p = 0.04). CHC patients with steatosis had significantly higher FGF21 levels compared with those without steatosis (p = 0.01). FGF21 concentration was positively related to steatosis grade (r = 0.39, p = 0.007). RBP4 levels did not differ between CHC patients and controls, but were negatively associated with necro-inflammatory activity grade (r = (-0.34), p = 0.04), with significantly higher levels in patients with minimal inflammatory activity (G1 vs. G2/3, p < 0.001; G1 vs. G2, p = 0 < 001; G1 vs. G3, p = 0.01). After stepwise linear regression analysis adjusting for potential confounders, RBP4 levels retained their independent significance as a predictor of necro-inflammatory activity (β = -0.31; t = -2.15, p = 0.035) and FGF21 levels as a predictor of steatosis (β = 0.34; t = 2.31, p = 0.024). Serum FGF21 correlated with serum RBP4 levels (r = 0.32, p = 0.02). Conclusions. Serum FGF21 levels increased in CHC patients, especially in those with steatosis and were associated with steatosis grade. FGF21 seems to be a useful diagnostic marker in determining hepatic steatosis in CHC. A negative association between serum RBP4 and necro-inflammatory activity indicates that disease severity may determine RBP4 levels.     

Leptin, free leptin index, insulin resistance and liver fibrosis in children with non-alcoholic fatty liver disease

OBJECTIVE: Prevalence of non-alcoholic fatty liver disease (NAFLD) among children is increasing dramatically. It is unclear why some patients develop steatohepatitis (NASH), fibrosis and cirrhosis from steatosis, and others do not. A role for leptin has been claimed. This study aims to evaluate the relationship between leptin, insulin resistance (IR) and NAFLD in children. DESIGN AND METHODS: In 72 biopsy-proven NAFLD children (aged 9-18 years; 51M/21F), fasting leptin and its soluble receptor (sOB-R) were measured; free leptin index (FLI) was calculated as leptin/sOB-R; IR was estimated by homeostasis model assessment (HOMA-IR) and insulin sensitivity index (ISI-comp); glucose tolerance by oral glucose tolerance test (OGTT). Percentage of total body fat (TBF) by dual-energy X-ray absorptiometry (DXA) was available in 65 patients. RESULTS: Prevalence of diabetes, impaired fasting and/or after load glucose tolerance was 11%. HOMA-IR and ISI-comp values were 2.55 +/- 1.39 and 4.4 +/- 2. NASH was diagnosed in 38 and simple steatosis in 25 children; diagnosis was indeterminate in 29 children. Increased fibrosis, mostly of mild severity, was observed in 41 patients. Median NAFLD activity (NAS) score was 3.42 +/- 1.60. According to histology, levels of leptin and FLI increased as steatosis (leptin from 11.9 +/- 6.3 in score 1 to 17.4 +/- 6.9 in score 2 (P = 0.01) and 22.2 +/- 6.8 ng/ml in score 3 (P < 0.001); FLI 2.56 +/- 1.40, 3.57 +/- 0.34, 4.45 +/- 0.64 respectively (P = 0.05)); ballooning (from 13.7 +/- 6.7 in score 1 to 17 +/- 7.5 in score 2 (P = 0.001) and 22.1 +/- 7.1 ng/ml in score 3 (P = 0.01); FLI 2.81 +/- 1.50, 3.40 +/- 1.65, 4.57 +/- 1.67 (P = 0.01 between 0 and 2)); fibrosis (from 14.3 +/- 7 to18.3 +/- 6.9; P = 0.03; FLI 3.03 +/- 1.57 vs 3.92 +/- 077; P < 0.05) and NAS score (score 1-2: 12.9 +/- 6.9; score 3-4: 17 +/- 6.9 (P = 0.01); score 5-7: 22.9 +/- 7.5 ng/ml (P = 0.03); FLI 2.70 +/- 1.53, 3.12 +/- 1.53, 4.58 +/- 1.57 P = 0.01 and P = 0.05 between 1-2 vs 3-4 and 3-4 vs 5-7 respectively) worsened. Higher leptin correlated with more severe steatosis, ballooning and NAS score (r(0) = 0.6, 0.4 and 0.6 respectively; for all P < 0.001); FLI with ballooning (r(0) = 0.4, P < 0.0001), steatosis (r(0) = 0.5, P < 0.0001) and NAS score (r(0) = 0.5, P < 0.0001). CONCLUSIONS: Leptin and liver injury correlated independently of age, BMI and gender in the present study. Nevertheless, any causative role of leptin in NAFLD progression could be established. Thus, studies are needed to define whether the hormone plays a major role in the disease.     

脂肪组织瘦素基因与非酒精性脂肪肝的研究

目的探讨非酒精性脂肪肝(NAFLD)患者脂肪组织瘦素mRNA基因表达水平和胰岛素抵抗与血浆瘦素等的相关性。方法行熳性胆囊炎、胃溃疡、腹股沟疝等择期手术的NAFLD患者21例、对照组患者24例,于术中取少许腹部皮下和网膜脂肪组织送检。应用SYBR Green I实时定量逆转录聚台酶链反应法检测瘦素mRNA的表达水平,用稳态模型法计算胰岛素抵抗指数,用酶联免疫吸附法测定血浆瘦素和胰岛素水平。结果NAFLD和对照组瘦素基因表达值分别为1．32±0．12、0．99±0．05,1．10±0．09、0．87±0．13；瘦素基因表达和胰岛素抵抗指数与血浆瘦素浓度直接关联(r值分别为0．72、0．69,P值均＜0．05)。结论脂肪组织瘦素基因高表达是高瘦素血症的主要原因,肥胖和非肥胖的NAFLD患者存在瘦素抵抗和胰岛素抵抗,提示瘦素抵抗与胰岛素抵抗一样和NAFLD发病密切相关。     

Insulin resistance and metabolic syndrome in chronic liver diseases: old entities with new implications

Insulin resistance (IR) and metabolic syndrome have recently been implicated in the pathogenesis and progression of chronic liver diseases, especially chronic hepatitis C (CHC) and non-alcoholic fatty liver disease (NAFLD). In this review, we provide current information on their deleterious effect on the liver, with particular interest in those two entities. In NAFLD, IR causes both the accumulation of fat in hepatocytes and the progression to non-alcoholic steatohepatitis (NASH). Moreover, the presence of metabolic syndrome seems to be associated with severe fibrosis in NASH patients. In CHC, IR develops early in the course of the disease and precedes steatosis. It is also independently associated with histological severity and negatively affects treatment response, irrespective of genotype. Consequently, therapies targeting IR and metabolic syndrome could indirectly ameliorate the prognosis of both NAFLD and CHC. As specific therapies do not exist, patients with metabolic syndrome and CHC and NAFLD should be counseled to lose weight and ameliorate their glycemic control and lipid profile.     

Metabolic significance of nonalcoholic fatty liver disease in nonobese, nondiabetic adults

BACKGROUND: Obesity and type 2 diabetes are well-known risk factors for the development of nonalcoholic fatty liver disease (NAFLD). However, NAFLD is not rare in nonobese, nondiabetic adults. The aim of this study was to evaluate the metabolic significance of NAFLD in nonobese, nondiabetic adults. METHODS: This study examined 768 nonobese (body mass index [BMI] [calculated as weight in kilograms divided by the square of height in meters], > or =18.5 and <30) (460 normal-weight and 308 overweight subjects), nondiabetic individuals older than 30 years who participated in a medical checkup. All the subjects had negative serologic findings for hepatitis B and C viruses and had an alcohol intake less than 140 g/wk. A standard interview, anthropometrics, a biochemical study, and abdominal ultrasonography were conducted. RESULTS: The prevalence of NAFLD in the enrolled subjects was 23.4%. In the normal-weight (BMI, > or =18.5 and <25) and overweight (BMI, > or =25 and <30) groups, NAFLD was a significant predictor of insulin resistance and other metabolic disorders, including hypertriglyceridemia and hyperuricemia. The odds ratio of the metabolic disorders in subjects with NAFLD compared with those without NAFLD in the normal-weight group was higher than that in the overweight group. Multiple logistic regression analysis showed that sex, waist circumference, triglyceride level, and insulin resistance were independently associated with NAFLD in the normal-weight group. CONCLUSIONS: Nonalcoholic fatty liver disease is closely associated with metabolic disorders, even in nonobese, nondiabetic subjects. Nonalcoholic fatty liver disease can be considered an early predictor of metabolic disorders, particularly in the normal-weight population.     

Patients achieving clearance of HCV with interferon therapy recover from decreased retinol-binding protein 4 levels

Summary.  Retinol-binding protein 4 (RBP4) is a recently identified adipokine that is elevated in the blood in several insulin-resistant states. We investigated the association between plasma RBP4 and histological and biochemical characteristics of chronic hepatitis C (CHC), as well as changes in RBP4 levels following interferon therapy. Eighty-one patients with CHC infected with genotype 1 received treatment with peginterferon plus ribavirin. Histological data were available for 41 out of 81 patients before treatment, and the degree of fibrosis, inflammation and steatosis was assessed. Plasma levels of RBP4 were determined in serial samples (before, at the end of treatment, and at 6 months post-treatment). RBP4 levels were lower in CHC patients than in control subjects (34.6 ± 12.3 μg/mL vs 46.2 ± 10.5 μg/mL; P  ≤ 0.001). Higher RBP4 levels were linked to lower alanine aminotransferase (ALT) ( P  < 0.01), higher cholinesterase ( P  < 0.01), hyperlipidaemia ( P  < 0.01), hyperglycaemia ( P  < 0.05), and higher platelet ( P  < 0.01) count in CHC patients. Plasma RBP4 levels tended to decrease concomitantly with the grade of histological fibrosis, activity, and steatosis. RBP4 levels at baseline were not a predictor of the response to antiviral therapy in CHC patients. After peginterferon plus ribavirin therapy, only patients who had achieved clearance of hepatitis C virus had higher post-treatment RBP4 levels. This study suggests that an association between RBP4 levels and abnormal metabolic features, and that liver function may determine RBP4 levels in CHC patents. This is further supported by the observation that RBP4 levels increased significantly after treatment only in sustained virological response (SVR) patients and reached levels comparable to those of healthy subjects.     

Hepatic steatosis and insulin resistance are associated with severe fibrosis in patients with chronic hepatitis caused by HBV or HCV infection

Background and aims: Steatosis and insulin resistance (IR) are the major disease modifying in patients with chronic hepatitis C (CHC). Only few studies evaluated these features in patients with chronic hepatitis B (CHB). We aimed to assess the prevalence and the factors related to steatosis and IR in CHB patients, compared with CHC subjects, and to evaluate the potential association between these features and fibrosis severity. Material and methods: One hundred and seventy consecutive patients with CHB (28 HBeAg positive, 142 HBeAg negative), were evaluated using liver biopsy and metabolic measurements and matched for sex, age and body mass index with 170 genotype 1 CHC patients. IR was defined if HOMA‐IR>2.7. All biopsies were scored for grading and staging by Scheuer's score, and the steatosis was considered significant if ≥10%. Results: The prevalence of significant steatosis was similar in both CHB and CHC patients (31 vs. 38%; P=0.14). IR rate was significantly higher in CHC than in CHB patients (42 vs. 26%; P=0.002). Severe fibrosis (F3–F4), at multivariate analysis, was independently associated with older age (OR 1.050, 95% CI 1.009–1.093), steatosis >10% (OR 4.375, 95% CI 1.749–10.943), and moderate–severe necroinflammatory activity (OR 8.187, 95% CI 2.103–31.875), regardless of HBeAg status, in CHB patients, and with older age (OR 1.080, 95% CI 1.028–1.136), IR (OR 2.640, 95% CI 1.110–6.281), steatosis >10% (OR 3.375, 95% CI 1.394–8.171), and moderate–severe necroinflammatory activity (OR 8.988, 95% CI 1.853–43.593) in CHC patients. Conclusions: CHB patients had high steatosis prevalence, similar to CHC controls, but lower IR rate. Both steatosis and IR in CHC, and only steatosis in CHB, are independently associated with fibrosis severity.     

Hyperhomocysteinemia and the MTHFR C677T polymorphism promote steatosis and fibrosis in chronic hepatitis C patients

The factors and mechanisms implicated in the development of hepatitis C virus (HCV)-related steatosis are unknown. Hyperhomocysteinemia causes steatosis, and the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism induces hyperhomocysteinemia. We investigated the role of these factors in the development of HCV-related steatosis and in the progression of chronic hepatitis C (CHC). One hundred sixteen CHC patients were evaluated for HAI, fibrosis and steatosis grades, body mass index, HCV genotypes, HCV RNA levels, homocysteinemia, and the MTHFR C677T polymorphism. Hyperhomocysteinemia was associated with the TT genotype of MTHFR (r = 0.367; P = .001). Median values of homocysteine in the CC, CT, and TT genotypes of the MTHFR gene were 9.3, 12.2, and 18.6 micromol/L, respectively (P = .006). Steatosis correlated with the MTHFR polymorphism, homocysteinemia, HAI and fibrosis. Steatosis above 20% was significantly associated with fibrosis. Prevalence and high grade (>20%) of steatosis were 41% and 11% in CC, 61% and 49% in CT, and 79% and 64% in TT, respectively (P = .01). Relative risk of developing high levels of steatosis was 20 times higher for TT genotypes than CC genotypes. According to multivariate analysis, steatosis was independently associated with hyperhomocysteinemia (OR = 7.1), HAI (OR = 3.8), liver fibrosis (OR = 4.0), and HCV genotype 3 (OR = 4.6). On univariate analysis, fibrosis was associated with age, steatosis, MTHFR, homocysteinemia and HAI; however, on multivariate analysis, liver fibrosis was independently associated with age (P = .03), HAI (P = .0001), and steatosis (P = .007). In conclusion, a genetic background such as the MTHFR C677T polymorphism responsible for hyperhomocysteinemia plays a role in the development of higher degree of steatosis, which in turn accelerates the progression of liver fibrosis in CHC.     

Polymorphism in microsomal triglyceride transfer protein: a link between liver disease and atherogenic postprandial lipid profile in NASH?

Nonalcoholic fatty liver disease (NAFLD) is emerging as an independent cardiovascular risk factor, but mechanism(s) linking fatty liver to atherosclerosis are unknown. Microsomal triglyceride transfer protein (MTP) -493 G/T polymorphism modulates circulating lipid and lipoprotein levels in different subsets and has been linked to NAFLD. The impact of MTP -493 G/T polymorphism, adipokines, and diet on postprandial lipoprotein profile and liver disease was assessed in nonalcoholic steatohepatitis (NASH). Plasma lipids, triglyceride-rich lipoprotein subfractions, high-density lipoprotein-C (HDL-C), and oxidized low-density lipoprotein (LDL) after an oral fat load were cross-sectionally correlated to MTP -493 G/T polymorphism, dietary habits, adipokines, and liver histology in 29 nonobese nondiabetic patients with NASH and 27 healthy controls. The severity of liver histology, the magnitude of triglycerides (Tg), free fatty acid (FFA), and LDL-conjugated diene responses, and the fall in HDL-C and apoA1 were significantly higher in NASH G/G (66% of patients) than in the other genotypes, despite similar adipokine profile and degree of insulin resistance. Postprandial large intestinal very-low-density lipoprotein (VLDL) subfraction A increases independently predicted Tg (beta=0.48; P=.008), FFA (beta=0.47; P=0.010), HDL-C (beta=0.42; P=0.009), and LDL-conjugated diene (beta=0.52; P=0.002) responses. VLDL A apoB48 response was independently associated with liver steatosis (OR: 2.4; CI 1.7-9.6; P=0.031). Postprandial LDL-conjugated diene response predicted severe necroinflammation (OR: 3.3; CI 1.4-9.7; P=0.016) and fibrosis (OR: 2.8; CI 1.0-8,5; P=0.030); postprandial apoA1 fall predicts severe fibrosis (OR: 2.1; CI: 1.5-6.1; P=0.015). CONCLUSION: MTP -493 G/T polymorphism may impact NASH by modulating postprandial lipemia and lipoprotein metabolism; homozygous GG carriers have a more atherogenic postprandial lipid profile than the other genotypes, independently of adipokines and insulin resistance.     

Non-alcoholic fatty liver disease and insulin resistance: importance of risk factors and histological spectrum

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) has been associated with several metabolic conditions (MC) and secondary causes, but the relationship between insulin resistance (IR) and the underlying aetiology of NAFLD has not been extensively explored. OBJECTIVE: To determine the frequency of IR among NAFLD patients and to describe IR according to risk factors and histological findings of the disease. METHODOLOGY: A case-series study of 64 patients with clinical and histological diagnosis of NAFLD. IR was calculated by homeostasis model assessment (HOMA) and IR was considered when HOMA > or = 3. Histological grades of NAFLD were: stage 1, steatosis isolated; stage 2, steatosis and inflammation; stage 3, steatosis and ballooning degeneration; stage 4, steatosis and fibrosis and/or Mallory bodies. Fibrosis was graded 0-4 (cirrhosis). RESULTS: IR was found in 21 (33%) patients. Among those with IR, 16 patients (76%) had associated MC and five patients (24%) had exposure to petrochemicals. The mean value of HOMA varied from 3.5 in NAFLD associated with MC to 1.6 in patients with exposure to petrochemicals (P < 0.03). Waist circumference was the metabolic factor most strongly associated with IR (P < 0.005). Steatohepatitis (NASH) was observed in 54 (84.3%) cases. The HOMA mean value was significantly higher in patients with advanced fibrosis. CONCLUSIONS: IR occurred in 33% of the NAFLD patients, being more frequent among those with MC than among those with exposure to petrochemicals. The presence of IR in cases with advanced fibrosis suggests that it may influence the prognosis of NAFLD.     

Nonalcoholic steatohepatitis versus steatosis: Adipose tissue insulin resistance and dysfunctional response to fat ingestion predict liver injury and altered glucose and lipoprotein metabolism

Nonalcoholic fatty liver disease (NAFLD) ranges from simple steatosis (SS) to nonalcoholic steatohepatitis (NASH). Though liver-related risk seems confined to NASH, it is currently unclear whether NASH has a higher risk of cardiovascular disease (CVD) and diabetes than SS as a result of the coexistence of obesity and other cardiometabolic confounders. Adipose tissue is an emerging modulator of liver disease in NAFLD and of cardiometabolic disease in the general population. We evaluated in SS and NASH (1) glucose homeostasis and cardiovascular risk profile and (2) the effect of adipose tissue dysfunction, assessed in fasting conditions and postprandially, on liver injury, glucose and lipoprotein metabolism, and markers of early atherosclerosis. Forty nonobese, nondiabetic, normolipidemic biopsy-proven NAFLD patients (20 with SS and 20 with NASH) and 40 healthy subjects, matched for overall/abdominal adiposity and metabolic syndrome, underwent an oral fat load test, with measurement of plasma triglyceride-rich lipoproteins, oxidized low-density lipoproteins, adipokines, and cytokeratin-18 fragments, and an oral glucose tolerance test with minimal model analysis to yield glucose homeostasis parameters. Circulating endothelial adhesion molecules were measured, and adipose tissue insulin resistance (adipose IR) index and visceral adiposity index were calculated. Despite similar fasting values, compared to SS, NASH showed a more atherogenic postprandial lipoprotein profile, an altered adipokine response (i.e., higher resistin increase and an adiponectin fall), and hepatocyte apoptosis activation after fat ingestion. Adipose IR index, endothelial adhesion molecules, and hepatic insulin resistance progressively increased across NAFLD stages. NASH, but not SS, showed an impaired pancreatic β-cell function. On multiple regression analysis, adipose IR index and postprandial adiponectin independently predicted liver histology and altered cardiometabolic parameters. Conclusion: Adipose tissue dysfunction, including a maladaptive adipokine response to fat ingestion, modulates liver injury and cardiometabolic risk in NAFLD. (HEPATOLOGY 2012;56:933-942).     

Design and validation of a histological scoring system for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis in the absence of a history of significant alcohol use or other known liver disease. Nonalcoholic steatohepatitis (NASH) is the progressive form of NAFLD. The Pathology Committee of the NASH Clinical Research Network designed and validated a histological feature scoring system that addresses the full spectrum of lesions of NAFLD and proposed a NAFLD activity score (NAS) for use in clinical trials. The scoring system comprised 14 histological features, 4 of which were evaluated semi-quantitatively: steatosis (0-3), lobular inflammation (0-2), hepatocellular ballooning (0-2), and fibrosis (0-4). Another nine features were recorded as present or absent. An anonymized study set of 50 cases (32 from adult hepatology services, 18 from pediatric hepatology services) was assembled, coded, and circulated. For the validation study, agreement on scoring and a diagnostic categorization ("NASH," "borderline," or "not NASH") were evaluated by using weighted kappa statistics. Inter-rater agreement on adult cases was: 0.84 for fibrosis, 0.79 for steatosis, 0.56 for injury, and 0.45 for lobular inflammation. Agreement on diagnostic category was 0.61. Using multiple logistic regression, five features were independently associated with the diagnosis of NASH in adult biopsies: steatosis (P = .009), hepatocellular ballooning (P = .0001), lobular inflammation (P = .0001), fibrosis (P = .0001), and the absence of lipogranulomas (P = .001). The proposed NAS is the unweighted sum of steatosis, lobular inflammation, and hepatocellular ballooning scores. In conclusion, we present a strong scoring system and NAS for NAFLD and NASH with reasonable inter-rater reproducibility that should be useful for studies of both adults and children with any degree of NAFLD. NAS of > or =5 correlated with a diagnosis of NASH, and biopsies with scores of less than 3 were diagnosed as "not NASH."     

Insulin/insulin-like growth factor I hybrid receptors overexpression is not an early defect in insulin-resistant subjects

Hybrid receptors (HRs), insulin receptor (IR)/insulin-like growth factor I receptor (IGF-I-R) heterodimers have been reported increased in skeletal muscle of obese and type 2 diabetic patients and to contribute to the patient insulin resistance. To investigate whether or not the increased expression of hybrid receptors is an early defect (probably genetic) of insulin resistance, we measured by specific enzyme-linked immunosorbent assays both IR, IGF-I-R, and HR content in skeletal muscle of healthy nonobese, nondiabetic subjects either insulin sensitive or insulin resistant, and also in patients with moderate obesity. IR content was significantly reduced in insulin-resistant subjects both nonobese and obese, compared with insulin-sensitive subjects (2.32+/-0.26, 2.36+/-0.18, and 3.45+/-0.42 ng/mg protein, respectively, P = 0.002). In contrast, IGF-I-R content was similar in the three groups. Muscle HR content was not different in insulin-sensitive vs. insulin-resistant subjects (both nonobese and obese) (4.90+/-0.46, 4.69+/-0.29, and 4.91+/-0.25 ng/mg protein, respectively, P = not significant). These studies indicate that, in insulin-resistant subjects without diabetes or severe obesity, muscle IR content but not IGF-I-R or HR content is reduced. They do not suggest, therefore, a primary (genetic) role of increased HR as a cause of IR decrease and insulin resistance.     

Circulating retinol-binding protein 4 is associated with the development and regression of non-alcoholic fatty liver disease

AimRetinol-binding protein 4 (RBP4), primarily secreted by liver and adipose tissue, has been linked with non-alcoholic fatty liver disease (NAFLD). However, investigations on the relationships between RBP4 and NAFLD have produced inconsistent results. Therefore, the association between serum RBP4 levels and the development or regression of NAFLD was prospectively investigated.MethodsA total of 3389 Chinese adults, aged 40–75 years and followed-up for 3.09 years, were included and analyzed in the study. NAFLD was diagnosed by abdominal ultrasonography. Serum RBP4 levels were measured, and their relationship to NAFLD development and regression assessed.ResultsOf the 1318 participants without NAFLD at baseline, 410 developed NAFLD after follow-up. Baseline RBP4 was positively associated with incident NAFLD: the fully adjusted odds ratio (OR) was 2.01 with a 95% confidence interval (CI) of 1.33–3.04 (P = 0.003 for trend). After follow-up, a significant increase in RBP4 levels was observed in participants who developed NAFLD. On the other hand, in 1382 subjects diagnosed with NAFLD at baseline, 339 experienced NAFLD regression after follow-up. Thus, baseline RBP4 was inversely associated with NAFLD regression: the fully adjusted OR was 0.52 with a 95% CI of 0.34–0.80 (P < 0.001 for trend). A significant decrease in RBP4 after follow-up was also noted in participants with NAFLD regression.ConclusionSerum RBP4 concentrations are associated with the development and regression of NAFLD, making them a potential novel preventative and therapeutic target in NAFLD management.     

Insulin resistance is independently associated with significant hepatic fibrosis in Asian chronic hepatitis C genotype 2 or 3 patients

Background and Aim: The role of insulin resistance (IR) and hepatic steatosis in fibrogenesis in chronic hepatitis C infection (CHC) has yielded conflicting data and few studies have been performed in Asian‐region populations. We retrospectively investigated the relationship between host metabolic variables, including IR and hepatic steatosis, to hepatic fibrosis in Asian‐region CHC genotype 2/3 patients. Methods: A total of 303 treatment‐naïve Asian‐region patients with CHC genotype 2/3 were enrolled in a multicenter phase 3 study of albinterferon alfa‐2b plus ribavirin for 24 weeks. IR was defined as Homeostasis Model for Assessment of IR (HOMA‐IR) > 2. Baseline liver biopsy was evaluated by a single expert histopathologist. Post hoc subgroup logistic regression modeling selected for independent variables associated with significant fibrosis (METAVIR stage F2‐F4). Results: Insulin resistance was available in 263 non‐diabetic Asian‐region patients (hepatitis C virus‐2 [HCV‐2] = 171, HCV‐3 = 92), and 433 non‐Asian region patients (407 “Caucasian”); METAVIR fibrosis prevalence F0‐F1 (minimal fibrosis) = 201 (77%) and F2‐F4 (significant fibrosis) = 59 (23%), and steatosis prevalence of grade 0 = 169 (65%), grade 1 = 64 (25%), grade 2/3 = 27 (10%). Median HOMA‐IR was 1.8 (interquartile range: 1.2–2.7); 100 (38%) patients had HOMA‐IR > 2. Factors independently associated with significant fibrosis included HOMA‐IR (odds ratio [OR] = 8.42), necro‐inflammatory grade (OR = 3.17), age (OR = 1.07) and serum total cholesterol levels (OR = 0.008). This was similar to non‐Asian region patients, but steatosis was not associated with significant fibrosis in either cohort. Conclusions: In this subgroup study of Asian‐region HCV genotype 2 or 3 patients, insulin resistance, along with age, cholesterol levels and necro‐inflammation, but not steatosis may be associated with significant hepatic fibrosis.     

Obesity and non-alcoholic fatty liver disease in chronic hepatitis C

BACKGROUND: Superimposed non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) may affect HCV-related fibrosis. We performed a study to determine the relationship between NAFLD and chronic hepatitis C. METHODS: One hundred and twenty patients with chronic hepatitis C and available liver biopsies were included. Baseline liver biopsies were read by 1 hepatopathologist using Metavir, as well as a fatty liver pathology protocol. Patients' baseline clinical, demographic, and virologic data were associated with the extent of steatosis (>33% vs. < or =33%), the type of fatty liver (no steatosis vs. steatosis only vs. NASH), and the stage of fibrosis seen on the liver biopsy. RESULTS: Seventy percent of patients were men and 80% were white. The mean age was 47.48+/-5.70 years, mean BMI was 29.01 +/-5.01 kg/m, and mean waist to hip ratio (W/H) was 0.90+/-0.08. Patients with higher grade of steatosis had higher BMI (32.83+/-6.26 vs. 28.49+/-4.62, P = 0.034), more likely to have genotype 3 (21.4% vs. 5.7%, P = 0.037) and advanced fibrosis (92.9% vs. 62.3%, P = 0.033) than those with lower grade of steatosis. Of these, only HCV-genotype 3 remained independently associated with higher grade of steatosis. When patients with superimposed NASH (n = 22) were compared with those with only steatosis (n = 49) and those without steatosis (n = 49), patients with superimposed NASH had more evidence of obesity (BMI: 30.64+/-5.23 vs. 29.90+/-5.35 vs. 27.33+/-4.07, P = 0.008; W/H: 0.97+/-0.06 vs. 0.91+/-0.08 vs. 0.87+/-0.07, P < 0.001), more commonly infected with HCV genotype 3 (14% vs. 12% vs. 0%, P = 0.036) and had more advanced fibrosis (95.5% vs. 75.5% vs. 42.9%, P < 0.001). Race, gender, and age did not affect extent of steatosis or presence of superimposed NASH. CONCLUSION: In conclusion, markers of obesity (BMI and W/H) and HCV genotype 3 are associated with the extent of steatosis and type of fatty liver. Higher grade of steatosis and presence of superimposed NASH are both associated with advanced hepatic fibrosis.     

The Q121 PC-1 variant and obesity have additive and independent effects in causing insulin resistance.

PC-1 is a membrane glycoprotein that impairs insulin receptor function. Its K121Q polymorphism is a genetic determinant of insulin resistance. We investigated whether the PC-1 gene modulates insulin sensitivity independently of weight status (i.e. both in nonobese and obese individuals). Nondiabetic subjects [164 males, 267 females; age, 37 +/- 0.6 yr, mean +/- SEM; body mass index (BMI), 32.7 +/- 0.5 kg/m(2)], who were subdivided into 220 nonobese (BMI < or = 29.9) and 211 obese, were studied. Although subjects were nondiabetic by selection criteria, plasma insulin concentrations during oral glucose tolerance test were higher (P < 0.05) in Q allele-carrying subjects (K121Q or Q121Q genotypes), compared with K121K individuals, in both the nonobese and obese groups. Insulin sensitivity, measured by euglycemic clamp in a representative subgroup of 131 of 431 randomly selected subjects, progressively decreased (P < 0.001) from nonobese K121K [n = 61; glucose disposal (M) = 34.9 +/- 1.1 micromol/kg/min] to nonobese Q (n = 21; M = 29.9 +/- 2.0), obese K121K (n = 31, M = 18.5 +/- 1.2), and obese Q (n = 18, M = 15.5 +/- 1.2) carriers. The K121Q polymorphism was correlated with insulin sensitivity independently (P < 0.05) of BMI, gender, age, and waist circumference. In conclusion, the Q121 PC-1 variant and obesity have independent and additive effects in causing insulin resistance.