Hepatitis C virus induced insulin resistance impairs response to anti viral therapy

Hepatitis C virus (HCV) infection is an important risk factor for insulin resistance (IR). The latter is the pathogenic foundation underlying metabolic syndrome, steatosis and cirrhosis, and possibly hepatocellular carcinoma (HCC). The interplay between genetic and environmental risk factors ultimately leads to the development of IR. Obesity is considered a major risk factor, with dysregulation of levels of secreted adipokines from distended adipose tissue playing a major role in IR. HCV-induced IR may be due to the HCV core protein inducing proteasomal degradation of insulin receptor substrates 1 and 2, blocking intracellular insulin signaling. The latter is mediated by increased levels of both tumour necrosis factor-α (TNF-α) and suppressor of cytokine signaling 3 (SOC-3). IR, through different mechanisms, plays a role in the development of steatosis and its progression to steatohepatitis, cirrhosis and even HCC. In addition, IR has a role in impairing TNF signaling cascade, which in turn blocks STAT-1 translocation and interferon stimulated genes production avoiding the antiviral effect of interferon.

Exposure to Electromagnetic Fields from Mobile Phones and Fructose consumption Coalesce to Perturb Metabolic Regulators AMPK/SIRT1-UCP2/FOXO1 in Growing Rats

Objective In this study,the combined effect of two stressors,namely,electromagnetic fields(EMFs)from mobile phones and fructose consumption,on hypothalamic and hepatic master metabolic regulators of the AMPK/SIRT1-UCP2/FOXO1 pathway were elucidated to delineate the underlying molecular mechanisms of insulin resistance.Methods Weaned Wistar rats(28 days old)were divided into 4 groups:Normal,Exposure Only(ExpO),Fructose Only(FruO),and Exposure and Fructose(EF).Each group was provided standard laboratory chow ad libitum for 8 weeks.Additionally,the control groups,namely,the Normal and FruO groups,had unrestricted access to drinking water and fructose solution(15%),respectively.Furthermore,the respective treatment groups,namely,the ExpO and EF groups,received EMF exposure(1,760 MHz,2 h/day x 8 weeks).In early adulthood,mitochondrial function,insulin receptor signaling,and oxidative stress signals in hypothalamic and hepatic tissues were assessed using western blotting and biochemical analysis.Result In the hypothalamic tissue of EF,SIRT1,FOXO 1,p-PI3K,p-AKT,ComplexⅢ,UCP2,MnSOD,and catalase expressions and OXPHOS and GSH activities were significantly decreased(P<0.05)compared to the Normal,ExpO,and FruO groups.In hepatic tissue of EF,the p-AMPKα,SIRT1,FOXO1,IRS1,p-PI3K,ComplexⅠ,Ⅱ,Ⅲ,Ⅳ,Ⅴ,UCP2,and MnSOD expressions and the activity of OXPHOS,SOD,catalase,and GSH were significantly reduced compared to the Normal group(P<0.05).Conclusion The findings suggest that the combination of EMF exposure and fructose consumption during childhood and adolescence in Wistar rats disrupts the closely interlinked and multi-regulated crosstalk of insulin receptor signals,mitochondrial OXPHOS,and the antioxidant defense system in the hypothalamus and liver.

Effect of soy protein supplementation in patients with chronic hepatitis C:A randomized clinical trial

AIM:To evaluate the effects of soy supplementation on insulin resistance,fatty liver and alanine aminotransferase(ALT) levels in non-diabetic patients with chronic hepatitis C(CHC).METHODS:In a prospective,randomized and singleblinded clinical trial,we compared patients with CHC who had casein as a supplement(n = 80)(control group),with patients who consumed a soy supplement diet(n = 80) [intervention group(IG)].Both groups received 32 g/d of protein for 12 wk.RESULTS:Patients' baseline features showed that 48.1% were overweight,43.7% had abdominal fat accumulation,34.7% had hepatic steatosis and 36.3% had an homeostasis model assessment index of insulin resistance(HOMA-IR) ≥ 3.0.Descriptive analysis showed that protein supplementation diet reduced hepatic steatosis in both groups;however,significant reductions in ALT levels occurred in the soy group.Multiple regression modeling indicated that in the presence of severe fibrosis(F3/F4),g glutamyl transferase elevation and high density lipoprotein(HDL) reduction,the intervention group had 75% less chance of developing hepatic steatosis(OR= 0.25;95% CI:0.06-0.82) and 55% less chance of presenting with an ALT level ≥ 1.5 × the upper limit of normal(ULN)(OR = 0.45,95% CI:0.22-0.89).Soy treatment did not have any effect on insulin resistance(OR = 1.92;95% CI:0.80-4.83),which might be attributed to the fact that the HOMAIR values at baseline in most of our patients were in the normal range.Advanced hepatic fibrosis,an ALT level > 1.5 × ULN and visceral fat were predictors of an HOMA-IR ≥ 3.The IG group had a reduced risk of an ALT level > 1.5 × ULN.An HOMA-IR ≥ 3.0 and HDL < 35 mg/dL were also risk factors for increased ALT.CONCLUSION:Soy supplementation decreased ALT levels and thus may improve liver inflammation in hepatitis C virus(HCV) patients;it also reduced hepatic steatosis in a subgroup of patients but did not change insulin resistance.It should be considered in the nutritional care of HCV patients.

Mixture of five herbal extracts ameliorates pioglitazone-induced aggravation of hepatic steatosis via activating the adiponectin receptor 2/AMP-activated protein kinase signal pathway in diabetic KKAy mice

OBJECTIVE: To assess the effect of a mixture of five herbal extracts(FT-5) on insulin resistance, glucose/lipid metabolism, hepatic steatosis, and to investigate whether the combination of FT-5 and pioglitazone would provide a robust effect on diabetes treatment, while may minimize undesirable side-effects of pioglitazone in diabetic Ay gene(KKAy)mice.METHODS: Seven-week-old KKAy mice were randomly divided into five groups: control(CON)group, FT-5(2.0 g/kg) group, pioglitazone(20 mg/kg)(PIO) group, pioglitazone(20 mg/kg) + FT-5(2.0 g/kg)(P + F) group. Age-matched C57 BL/6 J micewere used as the control group. After seven weeks of continuous intragastric administration of medication, the glucose metabolism, insulin sensitivity and lipid metabolism of KKAy mice were evaluated by assessing the fasting blood glucose(FBG), oral glucose tolerance test(OGTT), fasting serum insulin(FINS), insulin tolerance test(ITT), homeostasis model of assessment-insulin resistance index(HOMA-IR), total cholesterol(TC), total triglycerides(TG), and free fatty acids(FFA) in plasma and liver.Plasma and hepatic adiponectin were measured via enzyme-linked immunosorbent assays. Genes related to adipogenesis and lipolysis in white adipose tissues(WAT) and liver were examined by real-time polymerase chain reaction. Lipid metabolism-related protein expression in the liver of KKAy mice were detected by Western blotting.RESULTS: PIO treatment remarkably improved insulin resistance. However, it also showed substantial side effects. FT-5 group exhibited no significant decrease in serum glucose. However, it reduced fasting plasma TG levels and improved hepatic steatosis of KKAy mice. P + F group showed improved insulin resistance and similar body weight gain, as compared with control group. The m RNA expression of genes related to fatty acid oxidation was markedly up-regulated in the liver of P + F group.Pioglitazone administration markedly decreased the phosphorylation levels of AMPK, as compared with all other groups. Besides, even though plasma adiponectin increased in PIO, FT-5, P + F group, adipo R2 gene expression significantly decreased in the liver of PIO group.CONCLUSION: FT-5 decreased plasma TG and alleviated aggravating hepatic steatosis induced by pioglitazone in KKAy mice. FT-5's mechanism might be associated with its ability to activate the Adipo R2/AMPK pathway.