Interaction of metabolic syndrome, nonalcoholic fatty liver disease and chronic hepatitis C

Role of Angiotensin II in Non-Alcoholic Steatosis Development

Fatty liver is a multifactorial disease characterized by excessive accumulation of lipids in hepatocytes (steatosis), insulin resistance, oxidative stress, and inflammation. This disease has a major public health impact because it is the first stage of a chronic and degenerative process in the liver that can lead to steatohepatitis, cirrhosis, and liver cancer. Although this disease is mainly diagnosed in patients with obesity, type 2 diabetes mellitus, and dyslipidemia, recent evidence indicates that vasoactive hormones such as angiotensin II (ANGII) not only promote endothelial dysfunction (ED) and hypertension, but also cause fatty liver, increase adipose tissue, and develop a pro-steatotic environment characterized by a low-grade systemic pro-inflammatory and pro-oxidant state, with elevated blood lipid levels. The role of ANGII in lipid accumulation has been little studied, so this review aims to summarize existing reports on the possible mechanism of action of ANGII in inducing lipid accumulation in hepatocytes.

Interplay of PNPLA3 and HSD17B13 Variants in Modulating the Risk of Hepatocellular Carcinoma among Hepatitis C Patients

A single-nucleotide polymorphism causing a C to G change in the PNPLA3 gene (rs738409) is associated with disease severity and development of hepatocellular carcinoma (HCC) in nonalcoholic fatty liver disease; the insertion variant rs72613567:TA of the 17β-hydroxysteroid dehydrogenase type 13 (HSD17B13) mitigates this detrimental effect. Our aim was to evaluate if the same holds true in chronic hepatitis C virus infection (HCV). With a case control retrospective study design, we selected 110 patients who developed HCC on a background of HCV infection, matching each patient for sex and age (±30 months) to three HCV-infected, non-HCC patients. All participants underwent genotyping for PNPLA3 and HSD17B13 gene variants. Both univariate and multivariate analyses of risk factors for advanced disease and HCC were performed. Carriage of PNPLA3 G∗ allele was associated with a trend of progressively more severe liver disease, from mild fibrosis to significant fibrosis, cirrhosis, and HCC (p = 0.007). When the HSD17B13:TA status of these patients was taken into account, the abovementioned trend was strengthened among HSD17B13 major allele homozygotes and completely blunted among carriers of the minor allele (p = 0.0003 and 0.953, respectively). In a conditional logistic regression model including diabetes and AST to platelet ratio index among predictor variables, the unfavourable genetic profile characterized by the coexistence of the PNPLA3 minor allele and HSD17B13 major allele (vs. all other possible combinations) was an independent risk factor for HCC (OR = 2.00, 95% CI: 1.23-3.26) together with a history of alcohol abuse. In conclusion, carriage of the combination PNPLA3 minor allele and HSD17B13 major allele may represent a risk factor for HCC among HCV-infected patients. The interplay between the two genes may explain some of the controversy on this topic and may be exploited to stratify HCC risk in hepatitis C.

Investigation of the impact of birth by cesarean section on fetal and maternal metabolism

PURPOSE

Elective cesarean section (CS) was related to long-term adverse health effects in the offspring, but little is known about underlying mechanisms. Our study investigates the metabolic changes in both maternal and cord blood associated with CS in comparison to vaginal delivery (VD) to explore potential causal pathways.

METHODS

Samples obtained from PREOBE study participants were subjected to LC-MS/MS-targeted metabolomics comprising > 200 metabolites.

RESULTS

Elective CS showed an impact on both maternal and cord blood metabolomes. In maternal blood, the CS group showed lower levels of phospholipids (PL), principally ether-linked phosphatidylcholines (aaPC), pyruvic acid, branched chain keto-acids (BCKA), and other gluconeogenic substrates, but since the CS group showed different HDL levels in comparison to the VD group, we could not exclude contribution of the latter in the findings. In cord blood, the most remarkable finding in the CS group was the high levels of Cys; conversely, the lower levels of non-esterified fatty acids (NEFA), some tricarboxylic acid (TCA) cycle metabolites, gluconeogenic substrates, markers of β-oxidation, and the sum of hexoses were lower in CS-born babies in addition to tendentially lower levels of PL.

CONCLUSIONS

We speculate that lower levels of maternal and fetal corticosteroids in CS, due to less stressful condition, cause metabolic perturbations at birth initiating future negative health outcomes. This further supports the early programming hypothesis.

Prevalence and predictive factors of moderate/severe liver steatosis in chronic hepatitis C (CHC) infected patients evaluated with controlled attenuation parameter (CAP)

A novel controlled attenuation parameter (CAP) using FibroScan^® has been developed for assessment of liver steatosis. The aim was to evaluate the frequency and associated factors for moderate/severe steatosis evaluated by CAP in CHC patients submitted to transient elastography (TE) by FibroScan^® . CHC patients underwent TE with CAP evaluation. The classification of steatosis was defined as: CAP < 222 dB/m  =  S0; CAP ≥ 222 dB/m and <233dB/m  =  S1; ≥233 dB/m < 290dB/m  =  S2 and >= 290 dB/m  =  S3. The prevalence of moderate/severe steatosis (CAP ≥ S2) and the related independent factors were identified by a logistic regression analysis. A significance level of 5% was adopted. 1104 CHC patients, 85% genotype-1 were included (mean age 55 ± 11 years; 46% male, mean BMI 25 ± 4 Kg/m² ). Systemic arterial hypertension and type 2 diabetes mellitus prevalences were 39% and 17%, respectively. Liver stiffness measurement ≥ 9.5 kPa was observed in 39% of patients and steatosis was identified in 50% (S1 = 7%, S2 = 28% and S3 = 15%). The variables independently associated with moderate/severe steatosis were: male gender (OR=1.35; P = .037; 95% CI:1.01-1.81); systemic arterial hypertension (OR=1.57; P = .002; 95% CI:1.17-2.10) and BMI (OR=1.17; P < .01;95% CI:1.12-1.22). In conclusion, when CAP was adopted as a tool to detect steatosis, genotype 1 CHC patients presented a high prevalence of moderate/advanced steatosis. In these patients, liver steatosis was associated mostly to metabolic factors (arterial hypertension and high BMI).

The potential role of statins in treating liver disease

Statins are commonly use for the management of dyslipidemia, worldwide. Various studies have demonstrated that statins offer significant reduction in the risk of cardiovascular morbidity and mortality. However, this class of drugs has been implicated in potential liver toxicity, thus has been considered as a 'forbidden-drug' in patients with increased liver enzymes. Areas covered: Studies have shown that statins might offer clinical benefits in the setting of viral hepatitis, progression of cirrhosis, and hepatocellular carcinoma. More importantly, this class of drugs was shown to ameliorate liver histological (in both imaging and biopsy studies) and functional alterations in patients with non-alcoholic fatty liver disease or non-alcoholic steatohepatitis. In addition, two large survival studies have demonstrated reduction in the risk for cardiovascular events with statin use in patients with elevated transaminase levels at baseline. Expert commentary: These benefits were of greater extent compared with patients with normal liver function tests at baseline. However, current international guidelines seem to neglect these findings and are not including statins in the management algorithm of patients with non-alcoholic fatty liver disease or steatohepatitis. Future randomized studies providing biopsy-proven benefits will establish the use of statins in the prevention of cardiovascular events and therapeutic algorithm of these patients.

Audio-computer-assisted survey interview and patient navigation to increase chronic viral hepatitis diagnosis and linkage to care in urban health clinics

Intravenous drug use and sexual practices account for 60% of hepatitis C (HCV) and B (HBV) infection. Disclosing these activities can be embarrassing and reduce risk reporting, blood testing and diagnosis. In diagnosed patients, linkage to care remains a challenge. Audio-computer-assisted survey interview (Audio-CASI) was used to guide HCV and HBV infection testing in urban clinics. Risk reporting, blood testing and serology results were compared to historical controls. A patient navigator (PN) followed up blood test results and provided patients with positive serology linkage to care (LTC). Of 1932 patients surveyed, 574 (30%) were at risk for chronic viral hepatitis. A total of 254 (44.3%) patients were tested, 34 (13.5%) had serology warranting treatment evaluation, and 64% required HBV vaccination. Of 16 patients with infection, seven HCV and three HBV patients started treatment following patient LTC. Of 146 HBV-naïve patients, 70 completed vaccination. About 75% and 49% of HCV antibody and HBV surface antigen-positive patients were born between 1945 and 1965. Subsequently, automated HCV testing of patients born between 1945 and 1965 was built into our hospital electronic medical records. Average monthly HCV antibody testing increased from 245 (January-June) to 1187 (July-October). Patient navigator directed LTC for HCV antibody-positive patients was 61.6%. In conclusion, audio-CASI can identify patients at risk for HCV or HBV infection and those in need of HBV vaccination in urban medical clinics. Although blood testing once a patient is identified at risk for infection needs to increase, a PN is useful to provide LTC of newly diagnosed patients.

Pyruvate dehydrogenase kinase regulates hepatitis C virus replication

During replication, hepatitis C virus (HCV) utilizes macromolecules produced by its host cell. This process requires host cellular metabolic reprogramming to favor elevated levels of aerobic glycolysis. Therefore, we evaluated whether pyruvate dehydrogenase kinase (PDK), a mitochondrial enzyme that promotes aerobic glycolysis, can regulate HCV replication. Levels of c-Myc, hypoxia-inducible factor-1α (HIF-1α), PDK1, PDK3, glucokinase, and serine biosynthetic enzymes were compared between HCV-infected and uninfected human liver and Huh-7.5 cells infected with or without HCV. Protein and mRNA expression of c-Myc, HIF-1α, and glycolytic enzymes were significantly higher in HCV-infected human liver and hepatocytes than in uninfected controls. This increase was accompanied by upregulation of serine biosynthetic enzymes, suggesting cellular metabolism was altered toward facilitated nucleotide synthesis essential for HCV replication. JQ1, a c-Myc inhibitor, and dichloroacetate (DCA), a PDK inhibitor, decreased the expression of glycolytic and serine synthetic enzymes in HCV-infected hepatocytes, resulting in suppressed viral replication. Furthermore, when co-administered with IFN-α or ribavirin, DCA further inhibited viral replication. In summary, HCV reprograms host cell metabolism to favor glycolysis and serine biosynthesis; this is mediated, at least in part, by increased PDK activity, which provides a surplus of nucleotide precursors. Therefore, blocking PDK activity might have therapeutic benefits against HCV replication.

Clinical significance of enteral nutrition therapy for elderly patients with nonalcoholic fatty liver disease associated with metabolic syndrome

AIM: To explore the clinical significance of enteral nutrition therapy for elderly patients with nonalcoholic fatty liver disease associated with metabolic syndrome.

METHODS: A total of 120 patients diagnosed with nonalcoholic fatty liver disease with metabolic syndrome between May 2009 and May 2014 were randomly divided into either an enteral nutrition group or a parenteral nutrition group, with 60 cases in each group. The demographic data, such as age, sex and severity of illness, had no statistical difference (P > 0.05).

RESULTS: The body mass index (BMI), fasting plasma glucose (FPG), glycosylated hemoglobin (HbAlc), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), total bilirubin (TBIL), direct bilirubin (DBIL), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly in the enteral nutrition group after treatment (P < 0.05), although the waist-to-hip ratio, triceps skin fold (TSF), cholesterol, and high-density lipoprotein cholesterol (HDL-C) showed no obvious difference (P > 0.05) between before and after the treatment. In the parenteral nutrition group, the BMI, FPG and HbAlc significantly increased after therapy (P > 0.05), while the 2-h postprandial blood glucose level (2-h FBG), TC, HDL-C, and LDL-C had no significant changes (P > 0.05).

CONCLUSION: Enteral nutrition is more effective than parenteral nutrition in protecting liver functions, lowering the BMI and regulating sugar and fat metabolism in elderly patients with nonalcoholic fatty liver disease associated with metabolic syndrome.

Comparative diagnostic study of biomarkers using FibroMax™ and pathology for prediction of liver steatosis in patients with chronic hepatitis C virus infection: an Egyptian study

BACKGROUND

Steatosis is common in patients with hepatitis C virus (HCV) infection and may be a major determinant of progression of liver injury. This study evaluated FibroMax™ for noninvasive diagnosis of steatosis in patients with chronic HCV.

METHODS

This cross-sectional study included 44 patients naïve to treatment who were referred to our hepatology clinic for assessment of fitness for antiviral therapy. Chronic HCV infection was diagnosed by viral markers. Investigations included assessment of abdominal ultrasonography, liver biopsy, calculation of body mass index, and biomarker parameters in serum using FibroMax.

RESULTS

Histopathology of liver biopsies showed steatosis in 30 of 44 (68%) patients. FibroMax results were positively correlated with viral load by quantitative polymerase chain reaction and histopathological findings. Body mass index was significantly higher in steatotic patients (P = 0.003) and was significantly associated with the results on FibroMax (P = 0.005).

CONCLUSION

FibroMax was correlated with histopathology and body mass index in patients with HCV. Abdominal ultrasonography could not be used as a single tool to diagnose steatosis with HCV. Steatosis is correlated with viral load, which suggests a direct viral effect. We recommend FibroMax assessment in a larger number of patients to assess its applicability in patients with HCV and steatosis.

Progression of liver fibrosis in post-transplant hepatitis C: mechanisms, assessment and treatment

Liver fibrosis results from an excessive wound healing response in most chronic liver diseases, such as hepatitis C. Despite great advances in antiviral therapy in recent years, progressive liver fibrosis remains a major problem for patients with recurrent hepatitis C after liver transplantation. Liver biopsy remains a central tool in the management of HCV-positive liver transplant recipients, but reliable non-invasive methods for the assessment of liver fibrosis, such as ultrasound elastography, are increasingly being incorporated in the management of post-transplant patients, helping predict prognosis, guide treatment decisions, and stratify patients for emerging antifibrotic therapies. In this manuscript, we will review the natural history as well as tools to monitor fibrosis progression in the HCV-positive liver transplant recipient, the mechanisms underlying rapid fibrosis progression in up to 30% of these patients, the effect of antiviral therapies and highlight promising antifibrotic approaches.

The health implications of birth by Caesarean section

Since the first mention of fetal programming of adult health and disease, a plethora of programming events in early life has been suggested. These have included intrauterine and postnatal events, but limited attention has been given to the potential contribution of the birth process to normal physiology and long-term health. Over the last 30 years a growing number of studies have demonstrated that babies born at term by vaginal delivery (VD) have significantly different physiology at birth to those born by Caesarean section (CS), particularly when there has been no exposure to labour, i.e. pre-labour CS (PLCS). This literature is reviewed here and the processes involved in VD that might programme post-natal development are discussed. Some of the effects of CS are short term, but longer term problems are also apparent. We suggest that VD initiates important physiological trajectories and the absence of this stimulus in CS has implications for adult health. There are a number of factors that might plausibly contribute to this programming, one of which is the hormonal surge or "stress response" of VD. Given the increasing incidence of elective PLCS, an understanding of the effects of VD on normal development is crucial.

Insulin resistance, steatosis, and fibrosis in Egyptian patients with chronic Hepatitis C virus infection

BACKGROUND/AIM

Both nonalcoholic fatty liver disease (NAFLD) and chronic hepatitis C virus (HCV) infection are common in Egypt, and their coexistence is expected. There is controversy regarding the influence of NAFLD on chronic HCV disease progression. This study evaluates the effect of NAFLD on the severity of chronic hepatitis C (CHC) (necroinflammation and fibrosis) and assesses the relative contribution of insulin resistance syndrome to the occurrence of NAFLD in patients with chronic HCV infection.

PATIENTS AND METHODS

Untreated consecutive adults with chronic HCV infection admitted for liver biopsy were included in this study. Before liver biopsy, a questionnaire for risk factors was completed prospectively, and a blood sample was obtained for laboratory analysis.

RESULTS

Our study included 92 male patients. Their mean ± SD age and aspartate aminotransferase (AST) level were 42 ± 7.7 years (range 20-56) and 68 ± 41.7 U/L (range 16-214), respectively. The mean insulin level and insulin resistance index were 15.6 ± 18.3 mIU/mL (range 5.1-137.4) and 5.9 ± 15.2 (range 0.9-136.2), respectively. Fifty four percent of patients had steatosis and 65% had fibrosis. In multivariate analyses, steatosis was associated with insulin resistance and fibrosis was associated with high AST level, age ≥40 years, and steatosis.

CONCLUSIONS

Steatosis is a histopathologic feature in >50% of patients with chronic HCV infection. Insulin resistance has an important role in the pathogenesis of steatosis, which represents a significant determinant of fibrosis together with high serum AST level and older age.

Validation of endogenous reference genes for qRT-PCR analysis of human visceral adipose samples

Background

Given the epidemic proportions of obesity worldwide and the concurrent prevalence of metabolic syndrome, there is an urgent need for better understanding the underlying mechanisms of metabolic syndrome, in particular, the gene expression differences which may participate in obesity, insulin resistance and the associated series of chronic liver conditions. Real-time PCR (qRT-PCR) is the standard method for studying changes in relative gene expression in different tissues and experimental conditions. However, variations in amount of starting material, enzymatic efficiency and presence of inhibitors can lead to quantification errors. Hence the need for accurate data normalization is vital. Among several known strategies for data normalization, the use of reference genes as an internal control is the most common approach. Recent studies have shown that both obesity and presence of insulin resistance influence an expression of commonly used reference genes in omental fat. In this study we validated candidate reference genes suitable for qRT-PCR profiling experiments using visceral adipose samples from obese and lean individuals.

Results

Cross-validation of expression stability of eight selected reference genes using three popular algorithms, GeNorm, NormFinder and BestKeeper found ACTB and RPII as most stable reference genes.

Conclusions

We recommend ACTB and RPII as stable reference genes most suitable for gene expression studies of human visceral adipose tissue. The use of these genes as a reference pair may further enhance the robustness of qRT-PCR in this model system.

Hepatitis C and metabolic syndrome

Hepatitis C virus (HCV) and the hepatic manifestation of metabolic syndrome, nonalcoholic fatty liver disease, are the two major causes of chronic liver disease worldwide. Liver histology of both diseases can be associated with steatosis, oxidative stress and fibrogenesis. Although better defined for HCV, approximately 20% of patients with these diseases can also develop cirrhosis or hepatocellular carcinoma. In recent years, it has become clear that the presence of metabolic syndrome and nonalcoholic fatty liver disease negatively impacts HCV-related outcomes, while simultaneously, the progression of HCV may have metabolic consequences in that it encourages or exacerbates insulin resistance. A growing body of evidence suggests that successful treatment of HCV may rely on understanding and addressing the complex and often mutually confounding relationship between HCV and the individual elements that comprise metabolic syndrome.

Gene expression profile associated with superimposed non-alcoholic fatty liver disease and hepatic fibrosis in patients with chronic hepatitis C

BACKGROUND

Hepatic steatosis occurs in 40-70% of patients chronically infected with hepatitis C virus [chronic hepatitis C (CH-C)]. Hepatic steatosis in CH-C is associated with progressive liver disease and a low response rate to antiviral therapy.

AIM

Gene expression profiles were examined in CH-C patients with and without hepatic steatosis, non-alcoholic steatohepatitis (NASH) and fibrosis.

METHODS

This study included 65 CH-C patients who were not receiving antiviral treatment. Total RNA was extracted from peripheral blood mononuclear cells, quantified and used for one-step reverse transcriptase-polymerase chain reaction to profile 153 mRNAs that were normalized with six 'housekeeping' genes and a reference RNA. Multiple regression and stepwise selection assessed differences in gene expression and the models' performances were evaluated.

RESULTS

Models predicting the grade of hepatic steatosis in patients with CH-C genotype 3 involved two genes: SOCS1 and IFITM1, which progressively changed their expression level with the increasing grade of steatosis. On the other hand, models predicting hepatic steatosis in non-genotype 3 patients highlighted MIP-1 cytokine encoding genes: CCL3 and CCL4 as well as IFNAR and PRKRIR. Expression levels of PRKRIR and SMAD3 differentiated patients with and without superimposed NASH only in the non-genotype 3 cohort (area under the receiver operating characteristic curve=0.822, P-value 0.006]. Gene expression signatures related to hepatic fibrosis were not genotype specific.

CONCLUSIONS

Gene expression might predict moderate to severe hepatic steatosis, NASH and fibrosis in patients with CH-C, providing potential insights into the pathogenesis of hepatic steatosis and fibrosis in these patients.

Screening of proteins binding to HCV 1b NS3 protein from human pancreas cDNA library by yeast two-hybrid system

AIM: To screen proteins in pancreas cDNA library interacting with HCV 1b nonstructural protein NS3 and to study the biological functions of binding proteins.

METHODS: The pancreas cDNA library was amplified, purified and evaluated, and then the purified library plasmids were transformed into yeast strain Y187. The reconstructed plasmid pGBKT7-E1 was transformed into yeast strain AH109 and screened on the nutrient deficiency medium SD/-Trp. The transformed AH109 was mated with Y187 containing the library plasmid. The diploid yeast cells were plated on nutrient deficiency medium SD/-Trp/-Leu/-His/-Ade and SD/-Trp/-Leu/-His/-Ade containing X-α-gal for selection. The plasmids in diploid yeast cells were extracted and electrotransformed into E.coli DH5α. The plasmids in DH5α were extracted, sequenced and analyzed using bioinformatic methods.

RESULTS: The human pancreas cDNA library and bait plasmid (pGBKT7-NS3) were constructed successfully. The reconstructed bait plasmid was transformed into yeast cells AH109 successfully. 11 proteins interacting with HCV NS3 were screened.

CONCLUSION: These results show that HCV NS3 protein may be related with metabolism of glucose and lipid.