Evaluation and management of obesity-related nonalcoholic fatty liver disease

Serum Metrnl is Decreased in Metabolic Dysfunction-Associated Fatty Liver Disease: A Case-Control Study

Context

Metrnl is a novel adipokine mainly produced by white adipose tissue, which plays important roles in insulin sensitization, and energy homeostasis. However, information about the function of Metrnl in Metabolic dysfunction-associated fatty liver disease (MAFLD) remains unclear.

Methods

This is a control study, which enrolled 176 adults with MAFLD and 176 normal controls. They were matched in body mass index (BMI), age, and sex. Serum Metrnl was determined by ELISA. Other biochemical data were also collected.

Results

Compared to the controls, circulating Metrnl was prominently decreased in the MAFLD adults (P<0.001). Next, binary logistic regression model indicated that sex, waist circumference (WC), triglyceride, γ-gamma glutamyl transferase(γ-GGT), and Metrnl was independently associated with MAFLD. Further, as Metrnl levels elevated across its tertiles, the rate of MAFLD decreased (67.52, 66.95, and 15.38%; P value for trend<0.001). Data from multivariate logistic regression models evidenced that compared with the lowest tertile of Metrnl, the odds ratio of MAFLD was 0.023(95% CI 0.006-0.086, P<0.001) for the highest tertile after adjusting for potential confounders. Besides, area under ROC curve of Metrnl for diagnosis MAFLD was 0.755(95% CI 0.705-0.805). Metrnl was positively correlated with diastolic blood pressure, WC, BMI, systolic blood pressure, γ-GGT, and Creatinine in MAFLD. Finally, we found systolic blood pressure and Creatinine were independently related to serum Metrnl in MAFLD.

Conclusion

Serum Metrnl is reduced in adult with MAFLD. The results suggest that Metrnl may be a protective factor associated with the pathogenesis of MAFLD.

Detangling the interrelations between MAFLD, insulin resistance, and key hormones

Metabolic dysfunction-associated fatty liver disease (MAFLD) has increasingly become a significant and highly prevalent cause of chronic liver disease, displaying a wide array of risk factors and pathophysiologic mechanisms of which only a few have so far been clearly elucidated. A bidirectional interaction between hormonal discrepancies and metabolic-related disorders, including obesity, type 2 diabetes mellitus (T2DM), and polycystic ovarian syndrome (PCOS) has been described. Since the change in nomenclature from non-alcoholic fatty liver disease (NAFLD) to MAFLD is based on the clear impact of metabolic elements on the disease, the reciprocal interactions of hormones such as insulin, adipokines (leptin and adiponectin), and estrogens have strongly pointed to the intrinsic links that lead to the heterogeneous epidemiology, clinical presentations, and risk factors involved in MAFLD in different populations. The objective of this work is twofold. Firstly, there is a brief discussion regarding the change in nomenclature as well as epidemiology, risk factors, and pathophysiologic mechanisms other than hormonal effects, which include nutrition and the gut microbiome, as well as genetic and epigenetic influences. Secondly, we review the basis of the most important hormonal factors involved in the development and progression of MAFLD that act both independently and in an interrelated manner.

Water extract of Ferula lehmanni Boiss. prevents high-fat diet-induced overweight and liver injury by modulating the intestinal microbiota in mice

Obesity, often accompanied by hepatic steatosis, has been associated with an increased risk of health complications such as fatty liver disease and certain cancers. Ferula lehmannii Boiss., a food and medicine homologue, has been used for centuries as a seasoning showing anti-bacterial and anti-oxidant effects on digestive discomfort. In the present study, we sought to investigate whether a short-term oral administration of water extract of Ferula lehmanni Boiss. (WEFL) could prevent high-fat diet (HFD)-induced abnormal weight gain and hepatic steatosis in mice and its underlying mechanisms. WEFL reduced HFD-increased body weight, liver injury markers and inflammatory cytokines (i.e. IL-6 and IL-1β), and inhibited the elevation of AMPKα, SREBP-1c and FAS in HFD. Moreover, WEFL reconstructed the gut microbiota composition by increasing the relative abundances of beneficial bacteria, e.g. Akkermansia spp., while decreasing Desulfovibrio spp. and so on, thereby reversing the detrimental effects of HFD in mice. Removal of the gut microbiota with antibiotics partially eliminated the hepatoprotective effects of WEFL. Notably, WEFL substantially promoted the levels of short-chain fatty acids, especially butyric acid. To clarify the functional components at play in WEFL, we used UPLC-MS/MS to comprehensively detect its substance composition and found it to be a collection of polyphenol-rich compounds. Together, our findings demonstrate that WEFL prevented HFD-induced obesity and liver injury through the hepatic-microbiota axis, and such health-promoting value might be explained by the enriched abundant polyphenols.

Effect of Nigella sativa, atorvastatin, or L-Carnitine on high fat diet-induced obesity in adult male Albino rats

Obesity is increasing rapidly across the globe. It is widely accepted that natural products with a long safety background may modulate obesity. The current work aimed to investigate the effect of Nigella sativa, atorvastatin, or L-Carnitine on high-fat diet-induced obesity in white male albino rats. A regular basal diet was fed to 7 rats, and a high-fat diet (HFD) was fed to 24 rats throughout the study for 12 weeks. The HFD group was split equally into four subgroups, each containing six rats. The first group fed on HFD with no medication, the second group received HFD+ Nigella sativa, the third group received HFD+ atorvastatin, and the fourth group received HFD+L-carnitine. At the beginning of the seventh week (the start of the treatment regimen), Nigella sativa, atorvastatin, or L-Carnitine were administered for six weeks. Glucose, body weight, serum atherogenic index (AI), ALT, and AST activities were analyzed. The pathological alterations in the hepatic tissues were examined microscopically and scored. The results revealed that the HFD diet significantly increased the final body weight, serum AI, and serum levels of liver enzymes. Treatment with L-carnitine or Nigella sativa significantly normalized the lipid profile and decreased the final body weight, serum AI, and Serum ALT. Histopathological examination of the liver of HFD received rats showed features of steatosis, which were mitigated by the administration of Nigella sativa or L-Carnitine, while atorvastatin had no significant effect on the improvement of hepatic lesions. Collectively, study findings showed that Nigella sativa or L-Carnitine has mitigated effects on metabolic and histopathological changes in the liver tissues of rats fed with HFD.

The Role of IGF/IGF-1R Signaling in Hepatocellular Carcinomas: Stemness-Related Properties and Drug Resistance

Insulin-like Growth Factor (IGF)/IGF-1 Receptor (IGF-1R) signaling is known to regulate stem cell pluripotency and differentiation to trigger cell proliferation, organ development, and tissue regeneration during embryonic development. Unbalanced IGF/IGF-1R signaling can promote cancer cell proliferation and activate cancer reprogramming in tumor tissues, especially in the liver. Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death, with a high incidence and mortality rate in Asia. Most patients with advanced HCC develop tyrosine kinase inhibitor (TKI)-refractoriness after receiving TKI treatment. Dysregulation of IGF/IGF-1R signaling in HCC may activate expression of cancer stemness that leads to TKI refractoriness and tumor recurrence. In this review, we summarize the evidence for dysregulated IGF/IGF-1R signaling especially in hepatitis B virus (HBV)-associated HCC. The regulation of cancer stemness expression and drug resistance will be highlighted. Current clinical treatments and potential therapies targeting IGF/IGF-1R signaling for the treatment of HCC will be discussed.

Lutein attenuates excessive lipid accumulation in differentiated 3T3-L1 cells and abdominal adipose tissue of rats by the SIRT1-mediated pathway

OBJECTIVE

Obesity is now a worldwide disease and is mainly attributable to increased body fat deposition. In a growing number of epidemiological studies, lutein has been revealed to have different degrees of anti-obesity properties, but the potential underlying mechanisms that have been reported are limited. Therefore, we aimed to clarify the protective effects of lutein against excessive lipid accumulation, and we explored the role of SIRT1 and SIRT1-mediated pathways both in abdominal adipose tissue and mature 3T3-L1 cells during lutein administration.

METHODS

In our design, male Sprague-Dawley rats were fed either control or high-fat diets with or without 25 mg/kg·bw/day lutein for 5 weeks. Additionally, differentiated 3T3-L1 cells were incubated with 40 μM lutein or 10 μM Ex527 for 24 h.

RESULTS

Lutein supplementation decreased the body weight, abdominal fat index ratio, frequency and mean area of larger adipocytes in HE staining induced by the high-fat diet and then activated the expression of SIRT1 and thus upregulated FoxO1, ATGL, and HSL expression and downregulated SREBP-1, FAS, and ACC expression both in abdominal adipose tissue and differentiated 3T3-L1 cells. However, coincubation with Ex527 and lutein suppressed the activation of SIRT1 and reversed the expression of FoxO1, ATGL, HSL, SREBP-1, FAS, and ACC in comparison to those in the Lut group.

CONCLUSIONS

Overall, we suggest that the effects of lutein on attenuating excessive lipid accumulation are dependent on the SIRT1-mediated pathway in vivo and in vitro, which indicates that lutein administration may be a potential strategy for preventing excessive lipid accumulation and obesity.

Renal resistive index in non-alcoholic fatty liver disease as an indicator of early renal affection

Background

Nonalcoholic fatty liver disease (NAFLD) is a possible risk factor for chronic kidney disease (CKD). Renal resistive index (RRI) which is a ratio of peak systolic and end diastolic velocity can test arterial stiffness and endothelial renal dysfunction. The aim of the work is to detect the relation between NAFLD and RRI as an indicator of early renal affection and its relation to the disease severity. This study included 150 subjects divided into 3 groups: patients with NASH, simple steatosis, and control group (50 patients each). All patients were subjected to full history taking, clinical examination, laboratory investigations, abdominal ultrasound examination, and RRI measurement.

Results

6.0% of NASH patients had significant fibrosis by NAFLD fibrosis score. RRI was significantly higher in NASH patients with fibrosis (mean = 0.74) than NASH patients without fibrosis (mean = 0.65) and patients with simple steatosis (mean = 0.63). It was the lowest in normal controls (mean = 0.61). There were significant correlations between RRI and age, BMI, serum lipids, liver enzymes, and NAFLD fibrosis score. Multiple linear regression analysis found that age and serum cholesterol were significant independent factors of increased RRI (p < 0.0001). RRI showed low diagnostic performance in differentiation between NASH and simple steatosis using ROC curve.

Conclusion

RRI was significantly higher in NASH patients with and without hepatic fibrosis. RRI correlates significantly with NAFLD fibrosis score. RRI can be used as an indicator of early renal affection in patients with NAFLD.

A nomogram for estimating the probability of nonalcoholic fatty liver disease in a Chinese population: A retrospective cohort study

Studies have showed that dyslipidemia is closely related to nonalcoholic fatty liver disease (NAFLD). However, less attention has been paid to the relationship between early dyslipidemia and long-term risk of NAFLD. Therefore, we aimed to develop a simple-to-use nomogram to predict early dyslipidemia and long-term risk of NAFLD onset.A retrospective cohort study including 3621 employees (including retirees) from 7 companies was conducted between 2012 and 2019. Anthropometric, potential laboratory parameters and abdominal ultrasound were performed at baseline and after a 5-year follow-up. Cox proportional hazards model was used to determine predictors for NAFLD onset. The effects of lipids, age, body mass index (BMI), and serum uric acid (UA) on NAFLD were evaluated with the use of Kaplan-Meier curves (log-rank test). A nomogram was developed based on the Cox proportional hazard model and a 2-piecewise linear regression model. The accuracy of model was evaluated according to the area under the receiver operating characteristic curves.A total of 1545 subjects were included in the final analysis. The mean follow-up time was 52 ± 6.6 months. Of the total subjects, 77.61% were male and 22.39% were female. The mean age at the time of initial visit was 45.21 ± 11.20 years. Five hundred fifty-five subjects (35.92% of all subjects) were finally diagnosed with NAFLD. Variables in the nomogram included age, BMI, triglycerides, high-density lipoprotein, low-density lipoprotein, and UA. The accuracy of the nomogram for predicting 5-year cumulative occurrence of NAFLD was 0.8135 (95% confidence interval: 0.7921-0.8349), and the sensitivity and specificity were 0.8108 and 0.6960, respectively.The combination of age, BMI, triglycerides, high-density lipoprotein, low-density lipoprotein, and UA translated into a nomogram can reliably estimate the incidence of NAFLD within 5 years. It may serve as a decision support tool to determine whether to intervene at an early stage.

Pseudokinases: a tribble-edged sword

Advances in the understanding of the Tribbles family of pseudokinases (TRIB1, TRIB2 and TRIB3) reveal these proteins as potentially valuable biomarkers of disease diagnosis, prognosis, prediction and clinical strategy. In their role as signalling mediators and scaffolding proteins, TRIBs lead to changes in protein stability and activity, which impact on diverse cellular processes such as proliferation, differentiation, cell cycle and cell death. We review the role of TRIB proteins as promising therapeutic targets, with an emphasis on their role in cancer, and as biomarkers, with potential application across diverse pathological processes.

Mice lacking adenosine 2A receptor reveal increased severity of MCD-induced NASH

Adenosine 2A receptor (A2AR) exerts a protective role in obesity-related non-alcoholic fatty liver disease. Here, we examined whether A2AR protects against non-alcoholic steatohepatitis (NASH). In C57BL/6J mice, feeding a methionine- and choline-deficient diet (MCD) resulted in significant weight loss, overt hepatic steatosis, and massive aggregation of macrophages in the liver compared with mice fed a chow diet. MCD feeding also significantly increased the numbers of A2AR-positive macrophages/Kupffer cells in liver sections although decreasing A2AR amount in liver lysates compared with chow diet feeding. Next, MCD-induced NASH phenotype was examined in A2AR-disrupted mice and control mice. Upon MCD feeding, A2AR-disruptd mice and control mice displayed comparable decreases in body weight and fat mass. However, MCD-fed A2AR-disrupted mice revealed greater liver weight and increased severity of hepatic steatosis compared with MCD-fed control mice. Moreover, A2AR-disupted mice displayed increased severity of MCD-induced liver inflammation, indicated by massive aggregation of macrophages and increased phosphorylation states of Jun-N terminal kinase (JNK) p46 and nuclear factor kappa B (NFκB) p65 and mRNA levels of tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6. In vitro, incubation with MCD-mimicking media increased lipopolysaccharide (LPS)-induced phosphorylation states of JNK p46 and/or NFκB p65 and cytokine mRNAs in control macrophages and RAW264.7 cells, but not primary hepatocytes. Additionally, MCD-mimicking media significantly increased lipopolysaccharide-induced phosphorylation states of p38 and NFκB p65 in A2AR-deficient macrophages, but insignificantly decreased lipopolysaccharide-induced phosphorylation states of JNK p46 and NFκB p65 in A2AR-deficient hepatocytes. Collectively, these results suggest that A2AR disruption exacerbates MCD-induced NASH, which is attributable to, in large part, increased inflammatory responses in macrophages.

Analysis of amino acid profiles of blood over time and biomarkers associated with non-alcoholic steatohepatitis in STAM mice

The changes in free amino acid (AA) levels in blood during the progression from non-alcoholic steatohepatitis (NASH) to hepatocellular carcinoma (HCC) are unclear. We investigated serum AA levels, along with biochemical and histological events, in a mouse model of NASH. We induced NASH in male C57BL/6J mice with a streptozotocin injection and high-fat diet after 4 weeks of age (STAM group). We chronologically (6, 8, 10, 12, and 16 weeks, n=4–12 mice/group) evaluated the progression from steatohepatitis to HCC by biochemical and histological analyses. The serum AA levels were determined using an AA analyzer. Serum aspartate aminotransferase and alanine aminotransferase levels were higher in the STAM group than in the normal group (non-NASH-induced mice). Histological analysis revealed that STAM mice had fatty liver, NASH, and fibrosis at 6, 8, and 10 weeks, respectively. Moreover, the mice exhibited fibrosis and HCC at 16 weeks. The serum branched-chain AA levels were higher in the STAM group than in the normal group, especially at 8 and 10 weeks. The Fischer ratio decreased at 16 weeks in the STAM group, with increasing aromatic AA levels. These results suggested that this model sequentially depicts the development of fatty liver, NASH, cirrhosis, HCC, and AA metabolism disorders within a short experimental period. Additionally, serum amyloid A was suggested to be a useful inflammation biomarker associated with NASH. We believe that the STAM model will be useful for studying AA metabolism and/or pharmacological effects in NASH.

Cell-Free Circulating Nucleic Acids as Early Biomarkers for NAFLD and NAFLD-Associated Disorders

Non-alcoholic fatty liver disease (NAFLD) is the worldwide most common cause of chronic liver pathology, which prevalence strongly correlates with the increasing incidence of diabetes, obesity and metabolic syndrome in the general population. Simple steatosis, the earliest NAFLD stage, usually remains asymptomatic, and appropriate changes in the lifestyle, as well as the diet, can reverse the affected liver into the healthy state. The potential of simple steatosis to progress into severe fibrotic stages and to facilitate carcinogenesis necessitates timely NAFLD detection and risk stratification in community-based healthcare settings. Since their initial discovery a decade ago, extracellular circulating miRNAs have been found in all human biological fluids including blood and shown to hold great promises as non-invasive biomarkers. Normally, intracellular miRNAs participate in the regulation of gene expression, but once released by dying/dead cells they remain highly stable in the extracellular environment for prolonged periods. Therefore, circulating miRNA profiles can reflect the ongoing pathogenic processes in body's tissues and organs, and enable highly sensitive non-invasive diagnosis of multiple disorders. A non-urgent character of the NAFLD-related decision-making justifies the use of chronic liver diseases as an excellent test case for examining the practical utility of circulating miRNAs as biomarkers for longitudinal monitoring of human health. In this review, we summarize the state-of-the-art in the field of early diagnosis of NAFLD using circulating blood miRNAs, and stress the necessity of additional experimental validation of their diagnostic potential. We further emphasize on the potential diagnostics promises of other cell-free RNA species found in human biological fluids.

Association of Lipoprotein-Associated Phospholipase A2 with the Prevalence of Nonalcoholic Fatty Liver Disease: A Result from the APAC Study

Nonalcoholic fatty liver disease (NAFLD) is a worldwide chronic liver disease. Few studies have investigated the association between NAFLD and Lipoprotein-associated phospholipase A₂ (Lp-PLA₂), a unique enzyme correlated with oxidative stress. The aim of this study was to assess the relationship between Lp-PLA₂ and NAFLD in a Chinese community-based cohort. A total of 1587 adults aged ≥40 years were enrolled in the current study. Participants underwent a standardized evaluation. The serum Lp-PLA2 concentration was measured by ELISA and NAFLD was diagnosed by ultrasonography. Multivariable logistic regression was used to assess the association between Lp-PLA2 and NAFLD. Increased Lp-PLA2 levels were significantly associated with decreased NAFLD prevalence after adjusting for other potential confounders. The adjusted ORs of NAFLD in Q2, Q3 and Q4 compared with Q1 were 0.88 (0.64–1.21), 0.71 (0.51–0.98) and 0.67 (0.48–0.95), respectively (P < 0.05). Furthermore, the adjusted ORs of moderate and heavy NAFLD in Q2, Q3 and Q4 compared to Q1 were 0.64 (0.41–1.01), 0.48 (0.29–0.80) and 0.47 (0.28–0.79), respectively (P < 0.01). In conclusions, increased Lp-PLA2 levels were independently associated with decreased NAFLD prevalence.

Adipose tissue deficiency of hormone-sensitive lipase causes fatty liver in mice

Fatty liver is a major health problem worldwide. People with hereditary deficiency of hormone-sensitive lipase (HSL) are reported to develop fatty liver. In this study, systemic and tissue-specific HSL-deficient mice were used as models to explore the underlying mechanism of this association. We found that systemic HSL deficient mice developed fatty liver in an age-dependent fashion between 3 and 8 months of age. To further explore the mechanism of fatty liver in HSL deficiency, liver-specific HSL knockout mice were created. Surprisingly, liver HSL deficiency did not influence liver fat content, suggesting that fatty liver in HSL deficiency is not liver autonomous. Given the importance of adipose tissue in systemic triglyceride metabolism, we created adipose-specific HSL knockout mice and found that adipose HSL deficiency, to a similar extent as systemic HSL deficiency, causes age-dependent fatty liver in mice. Mechanistic study revealed that deficiency of HSL in adipose tissue caused inflammatory macrophage infiltrates, progressive lipodystrophy, abnormal adipokine secretion and systemic insulin resistance. These changes in adipose tissue were associated with a constellation of changes in liver: low levels of fatty acid oxidation, of very low density lipoprotein secretion and of triglyceride hydrolase activity, each favoring the development of hepatic steatosis. In conclusion, HSL-deficient mice revealed a complex interorgan interaction between adipose tissue and liver: the role of HSL in the liver is minimal but adipose tissue deficiency of HSL can cause age-dependent hepatic steatosis. Adipose tissue is a potential target for treating the hepatic steatosis of HSL deficiency.

Fatty liver is a major complication of obesity and of type 2 diabetes mellitus. It carries a high risk of cirrhosis and liver cancer. In fatty liver, triglycerides accumulate to high levels in the cytoplasm of hepatocytes. Triglycerides are degraded by lipolysis, which has been most studied in fat cells where its three steps are catalyzed by different enzymes. The second step, hydrolysis of diglyceride to a monoglyceride, can be mediated by hormone-sensitive lipase (HSL). Patients with genetic deficiency of HSL have fatty liver. In this study, we found that systemic HSL deficient mice developed fatty liver with aging. To study the mechanism of steatosis, we made liver-specific HSL-deficient mice. Surprisingly, these mice had normal liver fat content. We then studied mice with HSL deficiency in adipose tissue. Adipose HSL-deficient mice developed hepatic steatosis to a similar extent as mice with systemic HSL deficiency, showing that adipose HSL deficiency is sufficient to cause fatty liver. Furthermore, like reported HSL-deficient humans, mice with adipose HSL deficiency had systemic insulin resistance, reduced fat mass and inflammation in fat tissue. Each of these is known to promote hepatic steatosis. Livers of adipose HSL-deficient mice showed low levels of hepatic fatty acid (FA) oxidation, of very low density lipoprotein (VLDL) secretion and of triglycerides (TG) hydrolase activity, each of which could contribute to fat accumulation in liver. Tissue-selective genetic alterations may help in identifying and understanding the tissues responsible for complex metabolic phenotypes like fatty liver. Our data suggest that at least in mice, strategies for treatment of fatty liver related to HSL deficiency should concentrate on adipose tissue.

APOC3 Protein Is Not a Predisposing Factor for Fat-induced Nonalcoholic Fatty Liver Disease in Mice

Nonalcoholic fatty liver disease (NAFLD), characterized by excessive fat accumulation in liver, is prevalent in obesity. Genetic factors that link obesity to NAFLD remain obscure. Apolipoprotein C3 (APOC3) is a lipid-binding protein with a pivotal role in triglyceride metabolism. Humans with APOC3 gain-of-function mutations and mice with APOC3 overproduction are associated with hypertriglyceridemia. Nonetheless, it remains controversial whether APOC3 is culpable for diet-induced NAFLD. To address this fundamental issue, we fed APOC3-transgenic and wild-type littermates a high fructose diet or high fat diet, followed by determination of the effect of APOC3 on hepatic lipid metabolism and inflammation and the progression of NAFLD. To gain mechanistic insight into NAFLD, we determined the impact of APOC3 on hepatic triglyceride synthesis and secretion versus fatty acid oxidation. APOC3-transgenic mice were hypertriglyceridemic, culminating in marked elevation of triglycerides, cholesterols, and non-esterified fatty acids in plasma. Despite the prevailing hypertriglyceridemia, APOC3-transgenic mice, relative to wild-type littermates, had similar weight gain and hepatic lipid content without alterations in hepatic expression of key genes involved in triglyceride synthesis and secretion and fatty acid oxidation. APOC3-transgenic and wild-type mice had similar Kupffer cell content without alterations in hepatic expression of pro- and anti-inflammatory cytokines. APOC3 neither exacerbated diet-induced adiposity nor aggravated the degree of steatosis in high fructose or high fat-fed APOC3-transgenic mice. These effects ensued independently of weight gain even after 10-month high fat feeding. We concluded that APOC3, whose dysregulation is liable for hypertriglyceridemia, is not a predisposing factor for linking overnutrition to NAFLD in obesity.

Tribbles-1: a novel regulator of hepatic lipid metabolism in humans

The protein tribbles-1, encoded by the gene TRIB1, is increasingly recognized as a major regulator of multiple cellular and physiological processes in humans. Recent human genetic studies, as well as molecular biological approaches, have implicated this intriguing protein in the aetiology of multiple human diseases, including myeloid leukaemia, Crohn's disease, non-alcoholic fatty liver disease (NAFLD), dyslipidaemia and coronary artery disease (CAD). Genome-wide association studies (GWAS) have repeatedly identified variants at the genomic TRIB1 locus as being significantly associated with multiple plasma lipid traits and cardiovascular disease (CVD) in humans. The involvement of TRIB1 in hepatic lipid metabolism has been validated through viral-mediated hepatic overexpression of the gene in mice; increasing levels of TRIB1 decreased plasma lipids in a dose-dependent manner. Additional studies have implicated TRIB1 in the regulation of hepatic lipogenesis and NAFLD. The exact mechanisms of TRIB1 regulation of both plasma lipids and hepatic lipogenesis remain undetermined, although multiple signalling pathways and transcription factors have been implicated in tribbles-1 function. Recent reports have been aimed at developing TRIB1-based lipid therapeutics. In summary, tribbles-1 is an important modulator of human energy metabolism and metabolic syndromes and worthy of future studies aimed at investigating its potential as a therapeutic target.

Associated Factors for Metabolic Syndrome in the Older Adults with Chronic Virus Hepatitis in the Community

This study was to evaluate the association between metabolic syndrome (MetS) and chronic virus hepatitis elders in the community. Those subjects with positive hepatitis B surface antigen (HBsAg) and/or anti-hepatitis C virus (anti-HCV) screened in the community before were invited to this study and 451 responded. All participants underwent anthropometric measurements, blood tests, ultrasound and fibroscan examinations. The cut-off of liver stiffness measurement-liver cirrhosis (LSM-LC) was 10 kPa for chronic hepatitis B (CHB) patients and 12 kPa for chronic hepatitis C (CHC) patients, respectively. Among 451 responders, 56 were excluded due to negative HBsAg or anti-HCV. Three hundreds and ninety-five subjects included 228 CHB patients, 156 CHC patients and 11 dual hepatitis patients, had a mean age of 62±12.6 years. Fifty-four (23.7%) CHB patients coexisted with MetS whereas 40 (25.6%) CHC patients also had MetS. Those patients with MetS had more LSM-LC cases than those without (20.4% vs 9.8%, p = 0.04 in CHB patients; 28.2% vs 13.5%, p = 0.037 in CHC patients, respectively). In multivariate logistic analysis, detectable viremia was reversely associated with MetS in CHB patients after adjustment for age, gender and body mass index (odds ratio (OR): 0.42; 95% confidence interval (CI): 0.18-0.99; p = 0.047). Regarding CHC patients, higher LSM level was the only factor contributed to MetS (OR: 1.1; 95% CI: 1.02-1.19; p = 0.012). In conclusion, elder CHB patients coexisted with MetS might experience an inactive virus replication but have an advanced liver fibrosis. In elder CHC patients, only higher LSM level was associated with MetS.

Liver carcinogenesis: from naughty chemicals to soothing fat and the surprising role of NRF2

The liver is a key metabolic organ that is essential for production of blood proteins, lipid and sugar metabolism and detoxification of naturally occurring and foreign harmful chemicals. To maintain its mass and many essential functions, the liver possesses remarkable regenerative capacity, but the latter also renders it highly susceptible to carcinogenesis. In fact, liver cancer often develops in the context of chronic liver injury. Currently, primary liver cancer is the second leading cause of cancer-related deaths, and as the rates of other cancers have been declining, the incidence of liver cancer continues to rise with an alarming rate. Although much remains to be accomplished in regards to liver cancer therapy, we have learned a great deal about the molecular etiology of the most common form of primary liver cancer, hepatocellular carcinoma (HCC). Much of this knowledge has been obtained from studies of mouse models, using either toxic chemicals, a combination of fatty foods and endoplasmic reticulum stress or chronic activation of specific metabolic pathways. Surprisingly, NRF2, a transcription factor that was initially thought to protect the liver from oxidative stress, was found to play a key role in promoting HCC pathogenesis.

MicroRNAs in nonalcoholic fatty liver disease: novel biomarkers and prognostic tools during the transition from steatosis to hepatocarcinoma

Nonalcoholic fatty liver disease (NAFLD) is a metabolic-related disorder ranging from steatosis to steatohepatitis, which may progress to cirrhosis and hepatocellular carcinoma (HCC). The influence of NAFLD on HCC development has drawn attention in recent years. HCC is one of the most common malignant tumors and the third highest cause of cancer-related death. HCC is frequently diagnosed late in the disease course, and patient's prognosis is usually poor. Early diagnosis and identification of the correct stage of liver damage during NAFLD progression can contribute to more effective therapeutic interventions, improving patient outcomes. Therefore, scientists are always searching for new sensitive and reliable markers that could be analysed through minimally invasive tests. MicroRNAs are short noncoding RNAs that act as posttranscriptional regulators of gene expression. Several studies identified specific miRNA expression profiles associated to different histological features of NAFLD. Thus, miRNAs are receiving growing attention as useful noninvasive diagnostic markers to follow the progression of NAFLD and to identify novel therapeutic targets. This review focuses on the current knowledge of the miRNAs involved in NAFLD and related HCC development, highlighting their diagnostic and prognostic value for the screening of NAFLD patients.

Obesity-associated nonalcoholic fatty liver disease

Obesity is strongly associated with the prevalence of nonalcoholic fatty liver disease (NAFLD) in adult and pediatric populations. Nutrition, physical activity, and behavioral modifications are critical components of the treatment regimen for all obese patients with NAFLD. Bariatric surgeries that affect or restrict the flow of food through the gastrointestinal tract may improve liver histology in morbidly obese patients with nonalcoholic steatohepatitis (NASH), although randomized clinical trials and quasi-randomized clinical studies are lacking. Early detection of NASH and hepatic fibrosis using noninvasive biochemical and imaging markers that may replace liver biopsy is the current challenge.

Brain metabolic dysfunction at the core of Alzheimer's disease

Growing evidence supports the concept that Alzheimer's disease (AD) is fundamentally a metabolic disease with molecular and biochemical features that correspond with diabetes mellitus and other peripheral insulin resistance disorders. Brain insulin/IGF resistance and its consequences can readily account for most of the structural and functional abnormalities in AD. However, disease pathogenesis is complicated by the fact that AD can occur as a separate disease process, or arise in association with systemic insulin resistance diseases, including diabetes, obesity, and non-alcoholic fatty liver disease. Whether primary or secondary in origin, brain insulin/IGF resistance initiates a cascade of neurodegeneration that is propagated by metabolic dysfunction, increased oxidative and ER stress, neuro-inflammation, impaired cell survival, and dysregulated lipid metabolism. These injurious processes compromise neuronal and glial functions, reduce neurotransmitter homeostasis, and cause toxic oligomeric pTau and (amyloid beta peptide of amyloid beta precursor protein) AβPP-Aβ fibrils and insoluble aggregates (neurofibrillary tangles and plaques) to accumulate in brain. AD progresses due to: (1) activation of a harmful positive feedback loop that progressively worsens the effects of insulin resistance; and (2) the formation of ROS- and RNS-related lipid, protein, and DNA adducts that permanently damage basic cellular and molecular functions. Epidemiologic data suggest that insulin resistance diseases, including AD, are exposure-related in etiology. Furthermore, experimental and lifestyle trend data suggest chronic low-level nitrosamine exposures are responsible. These concepts offer opportunities to discover and implement new treatments and devise preventive measures to conquer the AD and other insulin resistance disease epidemics.

Nonalcoholic fatty liver disease is associated with low HDL cholesterol and coronary angioplasty in patients with type 2 diabetes

Background

There is evidence that nonalcoholic fatty liver disease (NAFLD) is associated with increased cardiovascular risk. In this study we examined factors associated with the presence of NAFLD and the prevalence of macroangiopathy in patients with type 2 diabetes.

Material/Methods

Subjects were 101 consecutive patients with type 2 diabetes: 72 with NAFLD and 29 free of NAFLD. NAFLD was diagnosed by ultrasonography. Serum lipids were measured enzymatically and glycated hemoglobin HbA1c was measured by HPLC.

Results

The mean age of patients was 53.1±10.4 in the NAFLD group and 44.9±10.9 years in patients without NAFLD (p<0.001). The mean duration of diabetes was 10±6.3 years in patients with NAFLD and 15.1±7.8 years in those without NAFLD (p<0.001). Mean values of glycated hemoglobin A1c were similar in both groups. Patients with NAFLD were characterized by a significantly higher prevalence of coronary angioplasty (20.8% vs. 0%, p=0.008). Overweight and obesity were observed in a higher percentage of patients with NAFLD (p<0.001). Patients with NAFLD were characterized by significantly higher values of alanine transaminase (p=0.033), and lower serum concentrations of HDL-cholesterol (p<0.001) and creatinine (p=0.034). Logistic regression analysis (p<0.001) revealed that NAFLD was positively associated with waist circumference above normal (women >80 cm, men >94 cm) (p=0.0083) and alanine transaminase activity (p=0.0164), and negatively with creatinine concentration (p=0.0226). In a second logistic regression model (p<0.001), waist circumference (p<0.007) and total cholesterol (p<0.008) were positive predictors, while HDL-C (p<0.003) was a negative predictor of NAFLD.

Conclusions

The results of the study suggest that NAFLD is associated with visceral obesity and low HDL-cholesterol in patients with type 2 diabetes.

The efficacy and safety of traditional chinese medicine (jiang zhi granule) for nonalcoholic Fatty liver: a multicenter, randomized, placebo-controlled study

Objective. To evaluate the efficacy and safety of Jiang Zhi Granule (JZG), a Chinese herbal formula, in patients with nonalcoholic fatty liver (NAFL). Methods. A multicenter, randomized, double-blind, placebo-controlled, parallel clinical trial was conducted for 24 weeks in 224 patients with NAFL at 6 university-affiliated hospitals. Patients were randomized 1 : 1 to receive JZG and placebo, respectively. Primary outcome was the change of liver to spleen ratio (L/S ratio) over computed tomography (CT). Secondary outcomes included body mass index (BMI), serum triglyceride (TG), and total cholesterol (TC) levels. Results. Of all the 224 eligible patients, 221 patients were analyzed in the full analysis set (FAS), 205 in the per protocol set (PPS), and 3 patients were withdrawn prematurely. For FAS, JZG significantly increased L/S ratio from 0.74 ± 0.21 to 0.99 ± 0.24 compared to that from 0.79 ± 0.18 to 0.85 ± 0.27 in placebo group (P = 0.0011). For PPS, it showed an increase of 0.26 ± 0.23 of L/S ratio in the patients on JZG versus 0.07 ± 0.22 in those on placebo (P = 0.0003). Superiority of JZG over placebo was also observed with greater reduction in BMI (P < 0.05) in both FAS and PPS. No observable difference in decrease of serum TC and TG was recorded (P > 0.05). There were no serious adverse events (AEs) in the study process and safety indices were normal in both groups. Conclusions. The Chinese herbal formula JZG was found to be superior to placebo in increasing L/S ratio and reducing BMI in NAFL patients. It was also well tolerated in patients and might be a safe and effective medicine for NAFL.

Eplerenone ameliorates the phenotypes of metabolic syndrome with NASH in liver-specific SREBP-1c Tg mice fed high-fat and high-fructose diet

Because the renin-angiotensin-aldosterone system has been implicated in the development of insulin resistance and promotion of fibrosis in some tissues, such as the vasculature, we examined the effect of eplerenone, a selective mineralocorticoid receptor (MR) antagonist, on nonalcoholic steatohepatitis (NASH) and metabolic phenotypes in a mouse model reflecting metabolic syndrome in humans. We adopted liver-specific transgenic (Tg) mice overexpressing the active form of sterol response element binding protein-1c (SREBP-1c) fed a high-fat and fructose diet (HFFD) as the animal model in the present study. When wild-type (WT) C57BL/6 and liver-specific SREBP-1c Tg mice grew while being fed HFFD for 12 wk, body weight and epididymal fat weight increased in both groups with an elevation in blood pressure and dyslipidemia. Glucose intolerance and insulin resistance were also observed. Adipose tissue hypertrophy and macrophage infiltration with crown-like structure formation were also noted in mice fed HFFD. Interestingly, the changes noted in both genotypes fed HFFD were significantly ameliorated with eplerenone. HFFD-fed Tg mice exhibited the histological features of NASH in the liver, including macrovesicular steatosis and fibrosis, whereas HFFD-fed WT mice had hepatic steatosis without apparent fibrotic changes. Eplerenone effectively ameliorated these histological abnormalities. Moreover, the direct suppressive effects of eplerenone on lipopolysaccharide-induced TNFα production in the presence and absence of aldosterone were observed in primary-cultured Kupffer cells and bone marrow-derived macrophages. These results indicated that eplerenone prevented the development of NASH and metabolic abnormalities in mice by inhibiting inflammatory responses in both Kupffer cells and macrophages.

Linagliptin alleviates hepatic steatosis and inflammation in a mouse model of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is a primary cause of cirrhosis and hepatocellular carcinoma. Dipeptidyl peptidase (DPP)-4 inhibitors are established therapies for type 2 diabetes and although DPP-4 inhibitors can reduce hepatic steatosis, their impact on local inflammation and fibrosis in NASH remains unknown. Using two different experimental treatment regimens (4- and 2-week treatments) in streptozotocin-treated neonatal mice on a high-fat diet, we show that the DPP-4 inhibitor linagliptin (10 and 30 mg/kg) significantly attenuated the NAS score from 4.9 ± 0.6 to 3.7 ± 0.4 and 3.6 ± 0.3, respectively, in the 4-week study. In the 2-week study, linagliptin 10 mg/kg significantly reduced NAS score from 4.1 ± 0.4 to 2.4 ± 0.4. Telmisartan was used as a positive control in both studies and lowered NAS score to 1.9 ± 0.7 and 1.4 ± 0.3, respectively. Due to streptozotocin treatment, elevated glucose levels were unchanged by either drug treatment. Further, linagliptin 10 mg/kg significantly reduced mRNA levels of SOCS-3 (from 1.68 ± 0.2 to 0.83 ± 0.08), IFN-γ (from 4.0 ± 0.5 to 2.3 ± 0.3), and TNF-α (from 5.7 ± 0.5 to 2.13 ± 0.3). The latter observation was confirmed by immunohistochemistry of TNF-α in liver specimens. In addition, using microautoradiography, we showed that the distribution of radiolabeled linagliptin was heterogeneous with the highest density associated with interlobular bile ducts and portal tracts (acini). In conclusion, these studies confirm that linagliptin has high exposure in hepatic tissue and has both anti-inflammatory and anti-steatotic activity in NASH.

Health benefits of blue-green algae: prevention of cardiovascular disease and nonalcoholic fatty liver disease

Blue-green algae (BGA) are among the most primitive life forms on earth and have been consumed as food or medicine by humans for centuries. BGA contain various bioactive components, such as phycocyanin, carotenoids, γ-linolenic acid, fibers, and plant sterols, which can promote optimal health in humans. Studies have demonstrated that several BGA species or their active components have plasma total cholesterol and triglyceride-lowering properties due to their modulation of intestinal cholesterol absorption and hepatic lipogenic gene expression. BGA can also reduce inflammation by inhibiting the nuclear factor κ B activity, consequently reducing the production of proinflammatory cytokines. Furthermore, BGA inhibit lipid peroxidation and have free radical scavenging activity, which can be beneficial for the protection against oxidative stress. The aforementioned effects of BGA can contribute to the prevention of metabolic and inflammatory diseases. This review provides an overview of the current knowledge of the health-promoting functions of BGA against cardiovascular disease and nonalcoholic fatty liver disease, which are major health threats in the developed countries.

Prospective histopathologic evaluation of lifestyle modification in nonalcoholic fatty liver disease: a randomized trial

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is now recognized as part of the metabolic syndrome, and is specifically related to obesity and insulin resistance. Lifestyle modification is advocated for the treatment of NAFLD, but few studies have evaluated its impact on liver histology. The purpose of this study was to investigate which, if any, specific diet and exercise recommendations are associated with histopathologic changes.

METHODS

A total of 56 participants were randomly assigned to 1 of 4 lifestyle modification subgroups for 6 months: standard care, low-fat diet and moderate exercise, moderate-fat/low-processed-carbohydrate diet and moderate exercise, or moderate exercise only. All subjects had biopsy-proven NAFLD, to include nonalcoholic steatohepatitis (NASH), and received a repeat 6-month biopsy to detect histopathologic changes. Other measures included blood assay of liver enzymes (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase), fasting glucose, serum insulin, lipid panel, body weight, dietary intake, fat mass, and fitness level.

RESULTS

Among the 41 participants who completed the study (88% with NASH), a significant change was found in pre- to post-NAFLD activity score in the group as a whole (p < 0.001) with no difference detected between subgroups (p = 0.31). Our results confirm that lifestyle modification is effective in improving NAFLD and NASH.

CONCLUSIONS

Regardless of intervention group, lifestyle modification improved liver histology, as verified by repeat biopsy, after a 6-month intervention. This study reinforces the importance of lifestyle modification as the primary treatment strategy for patients with NAFLD.

Effects of metabolic syndrome on fibrosis in chronic viral hepatitis

Background/Aims

Metabolic syndrome, comprising diabetes, hypertension, central obesity, and dyslipidemia, is increasingly prevalent worldwide. We aimed to study the relationship between metabolic syndrome and the risk of liver fibrosis in patients with chronic hepatitis B (CHB) and chronic hepatitis C (CHC).

Methods

In total, 954 patients (CHB, 850; CHC, 104 patients) with liver biopsy were included in the retrospective analysis. Extensive clinical and histological data were available. Metabolic syndrome was defined using the International Diabetes Federation definition of metabolic syndrome, 2006 criteria. Histological lesions were evaluated according to the histology activity index system.

Results

Metabolic syndrome was present in 6% of patients and significantly more prevalent in patients with CHC than in patients with CHB (5% vs 13%, p<0.001). Patients with metabolic syndrome were older among patients with CHB and patients with CHC, and, as expected, were mainly overweight or obese. Fibrosis was significantly more severe in patients with metabolic syndrome than in those without, regardless of whether they had CHB and CHC (CHB, 3.3±2.1 vs 2.4±1.3, p=0.025; CHC, 2.6±1.5 vs 1.3±0.7, p=0.006). Liver fibrosis (stages 3 to 4) was independently associated with increased age, higher transaminase level and metabolic syndrome (odds ratio, 2.421; p=0.017).

Conclusions

Metabolic syndrome is associated independently with severe fibrosis in patients with chronic viral hepatitis B and C.

Body mass index is the most useful predictive factor for the onset of nonalcoholic fatty liver disease: a community-based retrospective longitudinal cohort study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) can progress to advanced liver disease and non-liver-related diseases. To prevent NAFLD onset, clinicians must be able to easily identify high-risk NAFLD patients so that intervention can begin at an earlier stage. We sought to identify the predictive factors for NAFLD onset.

METHODS

In a community-based, longitudinal design, the records of 6,403 Japanese subjects were reviewed to identify those meeting the criteria for NAFLD onset. Univariate and multivariate logistic regression analyses were used to identify predictive factors for NAFLD onset. The accuracy of different models was evaluated according to their areas under the receiver operating characteristic curves. Comparative risk analysis was performed using the Kaplan-Meier method.

RESULTS

Multivariate analysis of 400 subjects who met the criteria for the onset of NAFLD during the observation period confirmed that body mass index (BMI) at baseline was the most useful predictive factor for NAFLD onset in both sexes. Cutoff levels of BMI for NAFLD onset were estimated at 23 kg/m2 for men and 22.2 kg/m2 for women. The cumulative onset rate of NAFLD was significantly higher in the high BMI group than in the low BMI group in both sexes (P < 0.001).

CONCLUSION

BMI was confirmed as the most useful predictive factor for NAFLD onset in both sexes; its cutoff levels were similar to those recommended by the World Health Organization for helping to prevent metabolic disease. An accurate BMI cutoff level will enable clinicians to identify subjects at risk for NAFLD onset.

A murine model for non-alcoholic steatohepatitis showing evidence of association between diabetes and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths. In addition to hepatitis viral infections, several cohort studies have shown that diabetes mellitus is a risk factor of HCC, making the incidence alarming high. However, it has not been demonstrated directly how diabetes develops to HCC, because of its difficulty to follow changes of liver histology in diabetic populations. Here, we report that non-alcoholic steatohepatitis (NASH) is pivotal to link diabetes with HCC by establishing a novel, reproducible NASH-HCC model in mice. Neonatal male mice exposed to low-dose streptozotocin (STZ) developed liver steatosis with diabetes 1 week after feeding high-fat diet (HFD). Continuous HFD decreased hepatic fat deposit whilst increased lobular inflammation with foam cell-like macrophages, showing NASH pathology. In parallel with decreased phagocytosis of macrophages, fibroblasts accumulated to form "chicken-wired" fibrosis. All mice developed multiple HCC later. Female mice treated with STZ-HFD and male mice treated with STZ alone showed diabetes but never developed HCC by the absence of NASH-based fibrosis. Thus, the present study provides the evidence in novel mouse model that NASH-based fibrosis is an essential histological process for diabetic populations to accelerate the development of HCC.

Synthesis and biological evaluation of 5-benzylidenepyrimidine-2,4,6(1H,3H,5H)-trione derivatives for the treatment of obesity-related nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), one of chronic liver diseases, seems to be rising as the obesity epidemic continues. In this study, 54 novel (thio)barbituric acid derivatives have been synthesized and evaluated for pharmacological activity. 7h exhibited potent glucose-lowering effects on insulin-resistant HepG2 cells and regulated adiponectin and leptin expression in 3T3-L1 adipocytes. Oral administration of 7h at 25 mg kg(-1) day(-1) for 4 weeks improved the progression of high fat diet-induced NAFLD by reducing the weight of body, liver, and fat, as well as modulating serum levels of fasting glucose, insulin, triglycerides, LDL-c, ALT, adiponectin and hepatic contents of triglycerides, total cholesterol. H&E stainings revealed that 7h blocked fat deposition in liver and the increase of adipocyte number and size in adipose tissues from NAFLD. Furthermore, treatment with 7h alleviated the obese clinical symptoms, recovered serum biomarkers to appropriate ranges, and improved glucose tolerance by OGTT and IGTT in DIO mice.

Studying non-alcoholic fatty liver disease with zebrafish: a confluence of optics, genetics, and physiology

Obesity is a public health crisis. New methods for amelioration of its consequences are required because it is very unlikely that the social and economic factors driving it will be reversed. The pathological accumulation of neutral lipids in the liver (hepatic steatosis) is an obesity-related problem whose molecular underpinnings are unknown and whose effective treatment is lacking. Here I review how zebrafish, a powerful model organism long-used for studying vertebrate developmental programs, is being harnessed to uncover new factors that contribute to normal liver lipid handling. Attention is given to dietary models and individual mutants. I speculate on the possible roles of non-hepatocyte residents of the liver, the adipose tissue, and gut microbiome on the development of hepatic steatosis. The highlighted work and future directions may lead to fresh insights into the pathogenesis and treatment of excess liver lipid states.

"Normal" liver stiffness values differ between men and women: a prospective study for healthy living liver and kidney donors in a native Korean population

BACKGROUND AND AIM

Liver stiffness (LS) measurement can distinguish individuals with potential liver disease (LD) from the general population. However, if LS is sex-sensitive, prevalence of LD may be incorrectly estimated when the same reference LS value is applied irrespective of sex. Here, we evaluated whether normal ranges of LS differ between healthy men and women.

METHODS

LS was measured in a cohort of healthy living liver and kidney donors, none of whom suffered from diabetes mellitus, hypertension, hepatitis B or C virus infection, heart or liver dysfunction, or metabolic syndrome. Patients with abnormal laboratory findings related to potential LD (platelet count < 150 × 10(3) /µL; aspartate aminotransferase > 40 IU/L; alanine aminotransferase [ALT] > 40 IU/L; albumin < 3.3 g/dL; total bilirubin > 1.2 mg/dL; gamma-glutamyl transpeptidase > 54 IU/L; alkaline phosphatase > 115 IU/L) were excluded.

RESULTS

Among 242 patients analyzed, the mean age was 34.1 for men (n = 121) and 40.5 years for women (n = 121) (P < 0.001). Men had a higher mean LS value than women (5.2 ± 1.2 vs 4.8 ± 1.1 kPa/P < 0.001). Multivariate-linear regression analysis identified sex as the only independent factor for LS values (β = 0.361/P = 0.021). Using the 5th-95th percentiles, we determined normal LS ranges of 3.7-7.0 kPa in men and 3.3-6.8 kPa in women. In subgroups with ALT < 30 IU/L (subgroup-1, n = 216) and ALT < 20 IU/L (subgroup-2, n = 163), men had significantly higher LS values than women (5.2 ± 1.3 vs 4.7 ± 1.1 kPa/P = 0.003 and 5.1 ± 1.2 vs 4.7 ± 1.1 kPa/P = 0.030, respectively), demonstrating an independent sex effect (β = 0.483/P = 0.003 and β = 0.389/P = 0.030, respectively).

CONCLUSIONS

An independent sex effect on LS values was confirmed. Thus, sex-specific references should be used for effective screening based on LS measurements.

A monocarboxylate transporter required for hepatocyte secretion of ketone bodies during fasting

To find new genes that influence liver lipid mass, we performed a genetic screen for zebrafish mutants with hepatic steatosis, a pathological accumulation of fat. The red moon (rmn) mutant develops hepatic steatosis as maternally deposited yolk is depleted. Conversely, hepatic steatosis is suppressed in rmn mutants by adequate nutrition. Adult rmn mutants show increased liver neutral lipids and induction of hepatic lipid biosynthetic genes when fasted. Positional cloning of the rmn locus reveals a loss-of-function mutation in slc16a6a (solute carrier family 16a, member 6a), a gene that we show encodes a transporter of the major ketone body β-hydroxybutyrate. Restoring wild-type zebrafish slc16a6a expression or introducing human SLC16A6 in rmn mutant livers rescues the mutant phenotype. Radiotracer analysis confirms that loss of Slc16a6a function causes diversion of liver-trapped ketogenic precursors into triacylglycerol. Underscoring the importance of Slc16a6a to normal fasting physiology, previously fed rmn mutants are more sensitive to death by starvation than are wild-type larvae. Our unbiased, forward genetic approach has found a heretofore unrecognized critical step in fasting energy metabolism: hepatic ketone body transport. Since β-hydroxybutyrate is both a major fuel and a signaling molecule in fasting, the discovery of this transporter provides a new direction for modulating circulating levels of ketone bodies in metabolic diseases.

The controlled attenuation parameter (CAP): a novel tool for the non-invasive evaluation of steatosis using Fibroscan

Steatosis is a reversible and benign condition. However, in a few cases, steatosis is associated with inflammation and hepatocyte changes, and is then defined as steato-hepatitis. Steatosis can also be a co-factor in many chronic liver diseases that can lead to fibrosis and cirrhosis. Although an important parameter, until now, evaluation of steatosis by non-invasive methods has remained challenging. In this paper, we report on the use of a novel non-invasive methodology called a controlled attenuation parameter (CAP). This is based on signals acquired by the Fibroscan, which was developed to specifically assess liver steatosis concomitant to liver stiffness measurements (LSM). CAP's performance from published articles and communications is also reported.

Care of chronic liver disease

Regardless of etiology, chronic liver disease generally involves a process of progressive destruction and regeneration of the liver parenchyma, leading to fibrosis and cirrhosis. At an early stage, most patients are asymptomatic and can easily go undiagnosed and untreated. Primary care physicians can often make the diagnosis but may offer little treatment. Better understanding about treatment is the key for primary care providers to provide better care for this group of patients. This review focuses on the treatment of the most common causes of chronic liver disease, including hepatitis B, hepatitis C, alcoholic cirrhosis, nonalcoholic fatty liver disease, and hemochromatosis.

Genome-wide association study identifies loci influencing concentrations of liver enzymes in plasma

Concentrations of liver enzymes in plasma are widely used as indicators of liver disease. We carried out a genome-wide association study in 61,089 individuals, identifying 42 loci associated with concentrations of liver enzymes in plasma, of which 32 are new associations (P = 10(-8) to P = 10(-190)). We used functional genomic approaches including metabonomic profiling and gene expression analyses to identify probable candidate genes at these regions. We identified 69 candidate genes, including genes involved in biliary transport (ATP8B1 and ABCB11), glucose, carbohydrate and lipid metabolism (FADS1, FADS2, GCKR, JMJD1C, HNF1A, MLXIPL, PNPLA3, PPP1R3B, SLC2A2 and TRIB1), glycoprotein biosynthesis and cell surface glycobiology (ABO, ASGR1, FUT2, GPLD1 and ST3GAL4), inflammation and immunity (CD276, CDH6, GCKR, HNF1A, HPR, ITGA1, RORA and STAT4) and glutathione metabolism (GSTT1, GSTT2 and GGT), as well as several genes of uncertain or unknown function (including ABHD12, EFHD1, EFNA1, EPHA2, MICAL3 and ZNF827). Our results provide new insight into genetic mechanisms and pathways influencing markers of liver function.

Correlation of fatty liver and abdominal fat distribution using a simple fat computed tomography protocol

AIM: To evaluate the relationship between hepatic fat infiltration and abdominal fat volume by using computed tomography (CT).

METHODS: Three hundred and six patients who visited our obesity clinic between November 2007 and April 2008 underwent fat protocol CT scans. The age range of the patients was 19 to 79 years and the mean age was 49 years. The male to female ratio was 116:190. Liver and spleen attenuation measurements were taken with three regions of interests (ROIs) from the liver and two ROIs from the spleen. Hepatic attenuation indices (HAIs) were measured as follows: (1) hepatic parenchymal attenuation (CT_LP); (2) liver to spleen attenuation ratio (LS ratio); and (3) difference between hepatic and splenic attenuation (LS_dif). Abdominal fat volume was measured using a 3 mm slice CT scan starting at the level of the umbilicus and was automatically calculated by a workstation. Abdominal fat was classified into total fat (TF), visceral fat (VF), and subcutaneous fat (SF). We used a bivariate correlation method to assess the relationship between the three HAIs and TF, VF, and SF.

RESULTS: There were significant negative correlations between CT_LP, LS ratio, and LS_dif with TF, VF, and SF, respectively. The CT_LP showed a strong negative correlation with TF and VF (r = -0.415 and -0.434, respectively, P < 0.001). The correlation between CT_LP and SF was less significant (r = -0.313, P < 0.001).

CONCLUSION: Fatty infiltration of the liver was correlated with amount of abdominal fat and VF was more strongly associated with fatty liver than SF.

A biomarker panel for non-alcoholic steatohepatitis (NASH) and NASH-related fibrosis

BACKGROUND

Patients with biopsy-proven NASH and especially those with fibrosis are at risk for progressive liver disease, emphasizing the clinical importance of developing non-invasive biomarkers for NASH and NASH-related fibrosis.

AIM

This study examines the performance of a new biomarker panel for NASH and NASH-related fibrosis with a combination of clinical and laboratory variables.

METHODS

Enrolled patients had biopsy-proven NAFLD. Clinical data, laboratory data, and serum samples were collected at the time of biopsy. Fasting serum was assayed for adiponectin, resistin, glucose, M30, M65, Tissue inhibitor of metalloproteinases-1 (Timp-1), ProCollagen 3 N-terminal peptide (PIIINP), and hyaluronic acid (HA). Regression models predictive of NASH, NASH-related fibrosis, and NASH-related advanced fibrosis were designed and cross-validated.

RESULTS

Of the 79 enrolled NAFLD patients, 40 had biopsy-proven NASH and 39 had non-NASH NAFLD. Clinical and laboratory data were from this cohort were used to develop a NAFLD Diagnostic Panel that includes three models (models for NASH, NASH-related fibrosis, and NASH-related advanced fibrosis). The model for predicting NASH includes diabetes, gender, BMI, triglycerides, M30 (apoptosis), and M65-M30 (necrosis) [AUC: 0.81, 95% CI, 0.70-0.89, 300 p value <9E 301 (-06)]. The NASH-related fibrosis prediction model includes the same predictors [AUC: 0.80, 95% CI 0.68-0.88, 307 p value <0.00014]. Finally, the NASH-related advanced fibrosis model includes type 2 diabetes, serum triglycerides, Timp-1, and AST [AUC: 0.81, 95% CI, 0.70-0.89; p value, 0.000062].

CONCLUSIONS

This NAFLD Diagnostic Panel based on a clinical and laboratory data has good performance characteristics and is easy to use. This biomarker panel could become useful in the management of patients with NAFLD.

Non-alcoholic steatohepatitis (NASH) in patients with polycystic ovarian syndrome (PCOS)

BACKGROUND

Both non-alcoholic steatohepatitis (NASH) and polycystic ovary syndrome (PCOS) are associated with metabolic syndrome (MS) and insulin resistance (IR). Except for a few case reports, there are no systematic assessments of NASH in PCOS patients.

AIM

To determine the prevalence of NASH and independent factors associated with NASH in a cohort of patients with documented PCOS.

METHODS

Patients with established diagnosis of PCOS and matched controls (matched for gender, age, and body mass index (BMI)) were included in the study. Causes of other liver diseases were systematically excluded by clinical and laboratory tests. Excessive alcohol use was defined as alcohol consumption of greater than 10 g/day. All liver biopsies were read by a single pathologist blinded to the clinical data. Histologic NASH was defined as steatosis with lobular inflammation and ballooning degeneration of hepatocytes with or without Mallory-Denk bodies or pericellular fibrosis. Univariate and multivariate analyses with logistic regression were performed to compare PCOS to matched controls.

RESULTS

Sixty-six patients were included in the study (34 PCOS and 32 matched controls). Of PCOS patients, 73% had a liver biopsy while 78% of the matched controls had a liver biopsy. In comparing PCOS patients to the matched controls, clinical (BMI, waist circumference, type 2 diabetes, MS, or its components, any alcohol consumption in the prior year, ethnic background, age, gender, etc.) and laboratory data (aminotransferases, ferritin, glucose, etc.) were not significantly different (p > 0.05). However, PCOS patients tended to have more histologic NASH on their liver biopsies (44.0% vs. 20.8%, p = 0.08). Independent predictors of histologic NASH in PCOS patients were elevated aspartate aminotransferase (AST), high triglycerides and small amounts of alcohol consumption (p = 0.019, 10-fold cross-validated AUC = 0.80, 95% CI = 0.56-0.94). Although about half of PCOS patients did not report any alcohol consumption, 50% did report rare alcohol use. In fact, PCOS patients with histologic NASH tended to report higher alcohol consumption per week than PCOS without NASH (3.80 ± 6.16 vs. 1.11 ± 1.87 g/week, p = 0.1). Nevertheless, these amounts of alcohol consumption were quite minimal.

CONCLUSIONS

Despite similar clinical and laboratory profiles to the matched controls, PCOS patients seem to have more histologic NASH. Although alcohol consumption was rare for both PCOS and controls, even rare alcohol consumption in PCOS patients was independently associated with histologic NASH.

Blockade of class IB phosphoinositide-3 kinase ameliorates obesity-induced inflammation and insulin resistance

Obesity and insulin resistance, the key features of metabolic syndrome, are closely associated with a state of chronic, low-grade inflammation characterized by abnormal macrophage infiltration into adipose tissues. Although it has been reported that chemokines promote leukocyte migration by activating class IB phosphoinositide-3 kinase (PI3Kγ) in inflammatory states, little is known about the role of PI3Kγ in obesity-induced macrophage infiltration into tissues, systemic inflammation, and the development of insulin resistance. In the present study, we used murine models of both diet-induced and genetically induced obesity to examine the role of PI3Kγ in the accumulation of tissue macrophages and the development of obesity-induced insulin resistance. Mice lacking p110γ (Pik3cg(-/-)), the catalytic subunit of PI3Kγ, exhibited improved systemic insulin sensitivity with enhanced insulin signaling in the tissues of obese animals. In adipose tissues and livers of obese Pik3cg(-/-) mice, the numbers of infiltrated proinflammatory macrophages were markedly reduced, leading to suppression of inflammatory reactions in these tissues. Furthermore, bone marrow-specific deletion and pharmacological blockade of PI3Kγ also ameliorated obesity-induced macrophage infiltration and insulin resistance. These data suggest that PI3Kγ plays a crucial role in the development of both obesity-induced inflammation and systemic insulin resistance and that PI3Kγ can be a therapeutic target for type 2 diabetes.

Gastrointestinal system and obesity

Several significant changes occur in the gastrointestinal system with obesity that can effect management in critical illness. This population is at risk for gastroesophageal reflux disease (GERD), abdominal compartment syndrome, nonalcoholic fatty liver disease (NAFLD), and an increased incidence of cholelithiasis. It is important for critical care providers to be aware of these potential complicating factors.

Clinical proteomics for liver disease: a promising approach for discovery of novel biomarkers

Hepatocellular carcinoma (HCC) is the fifth most common cancer and advanced hepatic fibrosis is a major risk factor for HCC. Hepatic fibrosis including liver cirrhosis and HCC are mainly induced by persistent hepatitis B or C virus infection, with approximately 500 million people infected with hepatitis B or C virus worldwide. Furthermore, the number of patients with non-alcoholic fatty liver disease (NAFLD) has recently increased and NAFLD can progress to cirrhosis and HCC. These chronic liver diseases are major causes of morbidity and mortality, and the identification of non-invasive biomarkers is important for early diagnosis. Recent advancements in quantitative and large-scale proteomic methods could be used to optimize the clinical application of biomarkers. Early diagnosis of HCC and assessment of the stage of hepatic fibrosis or NAFLD can also contribute to more effective therapeutic interventions and an improve prognosis. Furthermore, advancements of proteomic techniques contribute not only to the discovery of clinically useful biomarkers, but also in clarifying the molecular mechanisms of disease pathogenesis by using body fluids, such as serum, and tissue samples and cultured cells. In this review, we report recent advances in quantitative proteomics and several findings focused on liver diseases, including HCC, NAFLD, hepatic fibrosis and hepatitis B or C virus infections.

Increased arterial stiffness in nonalcoholic fatty liver disease: the Cardio-GOOSE study

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is a very frequent disease in Western countries. NAFLD shares with metabolic syndrome the same etiologic factors, such as obesity, diabetes, and dyslipidemia, which are also major cardiovascular risk factors. Cardio-GOOSE (Cardio-Gambettola ObservatOry liver Steatosis Estimation) is a population-based cohort study finalized to evaluate the relationship between NAFLD, subclinical vascular damage, and arterial stiffness.

METHODS

The study population consisted of 220 participants (123 women), aged between 30 and 70 years, who participated in the GOOSE study. Arterial stiffness was determined by measuring the carotid-femoral pulse wave velocity (PWV) by means of the PulsePen device. Preclinical atherosclerosis was detected by carotid intima-media thickness (IMT) measurement.

RESULTS

NAFLD was associated with metabolic syndrome in 48% of cases. IMT values were strongly related to metabolic syndrome factors. No significant differences in IMT were found between controls and patients with isolated NAFLD (0.77 +/- 0.15 mm versus 0.76 +/- 0.14 mm). Conversely, in patients with NAFLD associated with metabolic syndrome, IMT values were significantly higher than in patients with NAFLD alone (0.85 +/- 0.16 mm, P < 0.005). PWV values were significantly lower in controls compared to patients with isolated NAFLD (7.40 +/- 1.47 versus 7.98 +/- 1.51 m/s, P < 0.05) as well as patients with both NAFLD and metabolic syndrome (8.29 +/- 2.2 m/s, P < 0.001). The prevalence in NAFLD was increased in patients with the highest PWV values, and persisted after adjustment for factors determining metabolic syndrome (P < 0.05).

CONCLUSIONS

This study has shown a possible independent role of NAFLD in determining arterial stiffness.

Transient elastography in chronic hepatitis B: an Asian perspective

Transient elastography (TE) is a new non-invasive tool for assessing liver stiffness, which is correlated with the histologic stage of liver fibrosis. Many studies have reported a good accuracy of TE in predicting significant fibrosis and an optimal accuracy in predicting cirrhosis. Furthermore, the potential role of TE in screening the general population has also been proven. TE thus helps physicians to decide treatment strategies, predict prognosis, and monitor disease progression in patients with chronic liver disease and to screen the general population to identify high risk patients with potential liver disease. However, most data on the clinical roles of TE have been gathered in European patients with chronic hepatitis C (CHC), because TE was first developed in France. Accordingly, much data on the usefulness of TE in patients with CHC has accumulated. Recently, however, vigorous efforts have been made to apply TE to patients with chronic hepatitis B (CHB), and TE has also proved to have acceptable accuracy in diagnosing liver fibrosis and cirrhosis in these patients. Thus, we focused on TE in the Asian population with CHB in comparison with the European population with CHC and found that the diagnostic performance and cutoff values were different between the 2 populations possibly as a result of several different confounders between Asian and European populations (the etiology of chronic liver disease, histologic features, major fluctuation in alanine aminotransferase levels, and the prevalence of high body mass index and metabolic syndrome). Therefore, further studies tailored to the Asian population with CHB should be performed before the widespread application of TE in Asian populations with CHB.

Library of molecular associations: curating the complex molecular basis of liver diseases

Background

Systems biology approaches offer novel insights into the development of chronic liver diseases. Current genomic databases supporting systems biology analyses are mostly based on microarray data. Although these data often cover genome wide expression, the validity of single microarray experiments remains questionable. However, for systems biology approaches addressing the interactions of molecular networks comprehensive but also highly validated data are necessary.

Results

We have therefore generated the first comprehensive database for published molecular associations in human liver diseases. It is based on PubMed published abstracts and aimed to close the gap between genome wide coverage of low validity from microarray data and individual highly validated data from PubMed. After an initial text mining process, the extracted abstracts were all manually validated to confirm content and potential genetic associations and may therefore be highly trusted. All data were stored in a publicly available database, Library of Molecular Associations http://www.medicalgenomics.org/databases/loma/news, currently holding approximately 1260 confirmed molecular associations for chronic liver diseases such as HCC, CCC, liver fibrosis, NASH/fatty liver disease, AIH, PBC, and PSC. We furthermore transformed these data into a powerful resource for molecular liver research by connecting them to multiple biomedical information resources.

Conclusion

Together, this database is the first available database providing a comprehensive view and analysis options for published molecular associations on multiple liver diseases.

Nitrosamine exposure exacerbates high fat diet-mediated type 2 diabetes mellitus, non-alcoholic steatohepatitis, and neurodegeneration with cognitive impairment

Background

The current epidemics of type 2 diabetes mellitus (T2DM), non-alcoholic steatohepatitis (NASH), and Alzheimer's disease (AD) all represent insulin-resistance diseases. Previous studies linked insulin resistance diseases to high fat diets or exposure to streptozotocin, a nitrosamine-related compound that causes T2DM, NASH, and AD-type neurodegeneration. We hypothesize that low-level exposure to nitrosamines that are widely present in processed foods, amplifies the deleterious effects of high fat intake in promoting T2DM, NASH, and neurodegeneration.

Methods

Long Evans rat pups were treated with N-nitrosodiethylamine (NDEA) by i.p. Injection, and upon weaning, they were fed with high fat (60%; HFD) or low fat (5%; LFD) chow for 6 weeks. Rats were evaluated for cognitive impairment, insulin resistance, and neurodegeneration using behavioral, biochemical, molecular, and histological methods.

Results

NDEA and HFD ± NDEA caused T2DM, NASH, deficits in spatial learning, and neurodegeneration with hepatic and brain insulin and/or IGF resistance, and reductions in tau and choline acetyltransferase levels in the temporal lobe. In addition, pro-ceramide genes, which promote insulin resistance, were increased in livers and brains of rats exposed to NDEA, HFD, or both. In nearly all assays, the adverse effects of HFD+NDEA were worse than either treatment alone.

Conclusions

Environmental and food contaminant exposures to low, sub-mutagenic levels of nitrosamines, together with chronic HFD feeding, function synergistically to promote major insulin resistance diseases including T2DM, NASH, and AD-type neurodegeneration. Steps to minimize human exposure to nitrosamines and consumption of high-fat content foods are needed to quell these costly and devastating epidemics.

Epidemilogical trends strongly suggest exposures as etiologic agents in the pathogenesis of sporadic Alzheimer's disease, diabetes mellitus, and non-alcoholic steatohepatitis

Nitrosamines mediate their mutagenic effects by causing DNA damage, oxidative stress, lipid peroxidation, and pro-inflammatory cytokine activation, which lead to increased cellular degeneration and death. However, the very same pathophysiological processes comprise the "unbuilding" blocks of aging and insulin-resistance diseases including, neurodegeneration, diabetes mellitus (DM), and non-alcoholic steatohepatitis (NASH). Previous studies demonstrated that experimental exposure to streptozotocin, a nitrosamine-related compound, causes NASH, and diabetes mellitus Types 1, 2 and 3 (Alzheimer (AD)-type neurodegeneration). Herein, we review evidence that the upwardly spiraling trends in mortality rates due to DM, AD, and Parkinson's disease typify exposure rather than genetic-based disease models, and parallel the progressive increases in human exposure to nitrates, nitrites, and nitrosamines via processed/preserved foods. We propose that such chronic exposures have critical roles in the pathogenesis of our insulin resistance disease pandemic. Potential solutions include: 1) eliminating the use of nitrites in food; 2) reducing nitrate levels in fertilizer and water used to irrigate crops; and 3) employing safe and effective measures to detoxify food and water prior to human consumption. Future research efforts should focus on refining our ability to detect and monitor human exposures to nitrosamines and assess early evidence of nitrosamine-mediated tissue injury and insulin resistance.

Obesity, metabolic syndrome, and the surgical patient

Contemporary life, with its sedentary lifestyles, fast foods, processed foodstuff, and desk-bound service employment, is beset by an epidemic of overweight and obese individuals. The World Health Organization reported that worldwide a billion adults are overweight and at least 30% of them are obese. Moreover, increasing numbers of children are obese. In the United States, 2 National Health and Nutrition Examination Surveys of adults aged 20 to 74 years showed that the prevalence of obesity increased from 15% in the 1976 to 1980 survey to 34% in the 2003 to 2004 survey. Obesity and the metabolic syndrome are unfortunately becoming increasingly common perioperative issues. The ultimate aim of caring for such patients is to find ways to minimize the untoward effects of surgery in patients who are obese or have metabolic syndrome.